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[ { "abstract": "During the 21st century, the capability of best practice transfer will be a core competency of firms and a source of competitive advantage. This study reviews the practices of semiconductor firms and presents three models for the intrafirm transfer of best practices. These models have important implications for technology and knowledge management. First, replication strategies can apply not only to the service sector but also to manufacturing, including high tech firms. Second, these transfer models validate the contingency theory since various situations induce different transfer models. Third, external benchmarking may not always be the best way to solve problems and maintain competitive advantage. The resource based theory maintains that firms can retain a competitive edge by efficiently and effectively applying practices developed in house.", "author_names": [ "Iuan-yuan Lu", "Chih Jen Mao", "Chun-Hsien Wang" ], "corpus_id": 33978148, "doc_id": "33978148", "n_citations": 10, "n_key_citations": 1, "score": 1, "title": "Intrafirm technology and knowledge transfer: a best practice perspective", "venue": "Int. J. Technol. Manag.", "year": 2010 }, { "abstract": "The evolution of phosphorus (P) management decision support tools (DSTs) and systems (DSS) in support of food and environmental security has been most strongly affected in developed regions by national strategies (i) to optimize levels of plant available P in agricultural soils, and (ii) to mitigate P runoff to water bodies. In the United States, Western Europe, and New Zealand, combinations of regulatory and voluntary strategies, sometimes backed by economic incentives, have often been driven by reactive legislation to protect water bodies. Farmer specific DSSs, either based on modeling of P transfer source and transport mechanisms, or when coupled with farm specific information or local knowledge, have typically guided best practices, education, and implementation, yet applying DSSs in data poor catchments and/or where user adoption is poor hampers the effectiveness of these systems. Recent developments focused on integrated digital mapping of hydrologically sensitive areas and critical source areas, sometimes using real time data and weather forecasting, have rapidly advanced runoff modeling and education. Advances in technology related to monitoring, imaging, sensors, remote sensing, and analytical instrumentation will facilitate the development of DSSs that can predict heterogeneity over wider geographical areas. However, significant challenges remain in developing DSSs that incorporate \"big data\" in a format that is acceptable to users, and that adequately accounts for catchment variability, farming systems, and farmer behavior. Future efforts will undoubtedly focus on improving efficiency and conserving phosphate rock reserves in the face of future scarcity or prohibitive cost. Most importantly, the principles reviewed here are critical for sustainable agriculture.", "author_names": [ "Patrick J Drohan", "Marianne Bechmann", "Anthony R Buda", "Faruk Djodjic", "Donnacha G Doody", "Jon Duncan", "Antti Iho", "P Jordan", "P J Kleinman", "Richard William McDowell", "P -E Mellander", "I A Thomas", "Paul J A Withers" ], "corpus_id": 202081408, "doc_id": "202081408", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "A Global Perspective on Phosphorus Management Decision Support in Agriculture: Lessons Learned and Future Directions.", "venue": "Journal of environmental quality", "year": 2019 }, { "abstract": "In an effort to more rapidly develop their infrastructure, economies and living standards, many newly industrialised countries, such as Thailand, have embarked on a series of international Technology Transfer (TT) initiatives within the construction and other industries. However, these initiatives have not immediately translated into enhanced capabilities and competitiveness within indigenous firms, resulting in a sustained reliance on foreign firms. With few clues as to why TT ventures have not created expected outcomes for the indigenous construction industry, these countries lack direction on how to more rapidly diffuse best practice technology. In an attempt to improve rates of TT in the Thai construction industry, this paper reports on an attempt to appraise international TT performance on five large construction projects. A previously developed framework, developed by the authors, was utilised for this purpose and includes a total of six enabling and outcome perspectives, namely: (1) relationship building; (2) transferor characteristics; (3) transferee characteristics; (4) economic advancement; (5) knowledge advancement; and (6) project performance. A questionnaire survey was utilised to solicit TT performance scores from forty seven (47) Thai construction professionals working on these five projects. Summated TT performance scores are illustrated for the five companies using spider diagrams. Moreover, in depth discussion on the forces driving such scores is provided. Evaluating international TT on construction projects is the first step to assist host construction firms and government agencies to yield greater value from such initiatives.", "author_names": [ "Tanut Waroonkun", "Rodney Anthony Stewart" ], "corpus_id": 8826894, "doc_id": "8826894", "n_citations": 3, "n_key_citations": 1, "score": 0, "title": "Evaluating International Technology Transfer on Thai Construction Projects: A Case Study", "venue": "", "year": 2007 }, { "abstract": "The model of \"Open Innovations\" (OI) can be compared with the \"Triple Helix of University Industry Government Relations\" (TH) as attempts to find surplus value in bringing industrial innovation closer to public R&D. Whereas the firm is central in the model of OI, the TH adds multi centeredness: in addition to firms, universities and (e.g. regional) governments can take leading roles in innovation eco systems. In addition to the (transversal) technology transfer at each moment of time, one can focus on the dynamics in the feedback loops. Under specifiable conditions, feedback loops can be turned into feedforward ones that drive innovation eco systems towards self organization and the auto catalytic generation of new options. The generation of options can be more important than historical realizations \"best practices\" for the longer term viability of knowledge based innovation systems. A system without sufficient options, for example, is locked in. The generation of redundancy the Triple Helix indicator can be used as a measure of unrealized but technologically feasible options given a historical configuration. Different coordination mechanisms (markets, policies, knowledge) provide different perspectives on the same information and thus generate redundancy. Increased redundancy not only stimulates innovation in an eco system by reducing the prevailing uncertainty; it also enhances the synergy in and innovativeness of an innovation system.", "author_names": [ "Loet Leydesdorff", "Inga A Ivanova" ], "corpus_id": 13538083, "doc_id": "13538083", "n_citations": 82, "n_key_citations": 1, "score": 0, "title": "\"Open innovation\" and \"triple helix\" models of innovation: can synergy in innovation systems be measured?", "venue": "ArXiv", "year": 2016 }, { "abstract": "Clinical guidelines enable best medical evidence transfer to where best practice is needed. Although technology is considered the best way to reach this goal, the desired results have not been achieved yet.", "author_names": [ "Juan Manuel Pikatza Atxa", "Ander Iruetaguena", "David Buenestado", "Unai Segundo", "Juan Jose Garcia", "Luis Aldamiz-Echevarria", "Javier Elorz", "Raul Barrena", "Pablo Sanjurjo" ], "corpus_id": 46362824, "doc_id": "46362824", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Towards an Effective Knowledge Translation of Clinical Guidelines and Complementary Information", "venue": "DCAI", "year": 2010 }, { "abstract": "Innovation and Best Practices in Hospitality and Tourism Research contains 71 accepted papers from the Hospitality and Tourism Conference (HTC 2015, Melaka, Malaysia, 2 3 November, 2015) The book presents the \"up and coming\" paradigms and innovative practices within the hospitality and tourism industries, and covers the following topics: Management in Hospitality, Tourism, Foodservice and Gastronomy, Hospitality, Tourism and Foodservice Environment: Trends, New Concepts, and Developments, Education and Industry Linkages, Corporate Social Responsibility and Business Ethics in Hospitality and Tourism Industry, Economic Social Environmental Cultural Impact of Tourism, Global Perspectives on Business, Hospitality and Tourism. Marketing Channels, Issues and Transformations in Hospitality and Tourism Industry, Information and Communication Technologies in Hospitality and Tourism Industry, Marketing Approaches/ Strategies in Hospitality and Tourism Industry, Consumer Behaviour in Hospitality and Tourism Industry, Human Resource Management in Hospitality and Tourism, Health and Wellness Tourism, Gastronomic Tourism, Sports Tourism, Islamic/Halal Tourism and Hospitality Management, Tourism Security and Safety, Tourism Development and Planning, Green Technology and Strategies in Hospitality and Tourism, Food Safety, Quality and Innovations, Research and Knowledge Transfer, International Tourism and Management of Crisis, Infrastructure, Development and Sustainability in Hospitality and Tourism Industry, Trends in Entrepreneurial Activity in Business and Hospitality, Trends in Accommodation, Food and Beverage, Transportation, Leisure and Events, and Hospitality Training and Development. The contributions on diverse topics present new ideas and information on the \"stateof the art\" research into hospitality and tourism. Innovation and Best Practices in Hospitality and Tourism Research will indeed be a useful reference for academics, postgraduate students as well as professionals involved in the fields of hospitality and tourism.", "author_names": [ "Salamiah A Jamal" ], "corpus_id": 167796502, "doc_id": "167796502", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Innovation and best practices in hospitality and tourism research proceedings of the Hospitality Tourism Conference 2015, Melaka, Malaysia, 2 3 November 2015", "venue": "", "year": 2016 }, { "abstract": "The model of \"Open Innovations? (OI) can be compared with the \"Triple Helix of University Industry Government Relations? (TH) as attempts to find surplus value in bringing industrial innovation closer to public R&D. Whereas the firm is central in the model of OI, the TH adds multi centeredness: in addition to firms, universities and (e.g. regional) governments can take leading roles in innovation eco systems. In addition to the (transversal) technology transfer at each moment of time, one can focus on the dynamics in the feedback loops. Under specifiable conditions, feedback loops can be turned into feedforward ones that drive innovation eco systems towards self organization and the auto catalytic generation of new options. The generation of options can be more important than historical realizations \"best practices? for the longer term viability of knowledge based innovation systems. A system without sufficient options, for example, is locked in. The generation of redundancy the Triple Helix indicator can be used as a measure of unrealized but technologically feasible options given a historical configuration. Different coordination mechanisms (markets, policies, knowledge) provide different perspectives on the same information and thus generate redundancy. Increased redundancy not only stimulates innovation in an eco system by reducing the prevailing uncertainty; it also enhances the synergy in and innovativeness of an innovation system.", "author_names": [ "Loet Leydesdorff", "Inga A Ivanova" ], "corpus_id": 197781202, "doc_id": "197781202", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "'Open Innovation' and 'Triple Helix' Models of Innovation: Can Synergy in Innovation Systems Be Measured?", "venue": "", "year": 2016 }, { "abstract": "Given the predominance of the 'psy' sciences in the gambling studies field, more theorizing of the kind that Young (2013) has done is sorely needed. Importantly, Young points to the role of researchers in creating the social construct of 'problem gambler' as part of the larger transfer of risk from governments and industries to individual consumers. However, we question what seems to be his view of prevalence research as a tool of legitimation and nothing more. As we have argued elsewhere (Volberg Wray, 2007) the gambling research arena suffers from at least two fundamental weaknesses; first, the lack of a constructionist perspective, which has led researchers to neglect the symbolic power of the problem gambling construct, and second, the lack of a structural perspective, which has led researchers to neglect the role of historical, economic and political forces in the legalization of gambling. This latter, structural perspective is not fully articulated by Young. To complement his focus on PGPSs, we believe it is essential to 'follow the money' (Safire, 1997) and investigate the social origins and destinations of the wealth that flows into and out of the legalized gambling arena. The dominance of the 'psy' sciences in the evolution of the 'problem gambler' construct has resulted in a vast literature that targets the individual but neglects important macro level dynamics of gambling. However, as Bernhard, Futrell, and Harper (2009) point out, while homogenization and isomorphic trends are evident in gambling spaces worldwide, there are also divergences in how local gambling industries develop, such that efforts to export Western practices have met with resistance. These investigators point to both homogenization and resistance in the global emergence of the 'problem gambling industry' and cite the example of South Korea, where Westernstyle 'best practices' in providing help to problem gamblers were spectacularly unsuccessful and had to be replaced with services that fit more appropriately with how gambling problems are managed in that culture (Bernhard et al. 2009) Prevalence studies are not just tools of domination. As forms of expert knowledge, they have a doubleedge that can cut both ways. Medical sociologists and social movement researchers have repeatedly shown how laypersons repurpose expert knowledge to suit their own ends, subverting and contesting the efforts of industries, institutions, and governments to use that knowledge to legitimate or normalize controversial technologies, policies, or diagnoses (Futrell, 2003) By extension, such 'lay experts' (Prior, 2003) may use PGPSs to help construct their own forms of 'popular epidemiology' (Brown, 1992) that represent the suffering of the categorized and afflicted rather than the economic and political interests of the categorizers. In the present context, a single example will have to suffice. In the ongoing battle over casino development in Philadelphia, community activists in Chinatown successfully opposed plans, backed by both the city and the state, to locate a casino in their neighborhood. Their protest strategy placed great significance on the findings from PGPS research that Asian populations particularly older, Asian males have higher rates of PG and are thus more vulnerable to harms associated with casino gambling (M. Yee, Chinatown Preservation Alliance, personal communication to Wray, May 27, 2009) That prevalence studies are more often used to legitimate and normalize gambling than to oppose it does not minimize the significance of this point, one we did not properly emphasize in our earlier work (Volberg Wray, 2007) We think this repurposing of expert knowledge by laypersons is one way to answer Young's call for a reflexive (re)placement' of prevalence studies. We are encouraged by Young's contribution. But we would plead for a broader perspective that asks whether, and how, non experts use PGPSs to resist or reduce gambling harms in their communities.", "author_names": [ "Rachel A Volberg", "Matt Wray" ], "corpus_id": 144968156, "doc_id": "144968156", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Beyond social control: Prevalence research and the uses of expert knowledge", "venue": "", "year": 2013 }, { "abstract": "The constant and rapid changes in the world over the last decades as the result of social, political and economic determinants have caused changes in the health care of the globalized society with consequent modifications of the epidemiological profile, increase in the complexity of health problems and in the demand of individuals. These factors compel the different disciplines of knowledge, specifically in health, to adapt their care processes, aiming at finding solutions for the real or potential needs of the individual. In this scenario, we emphasize Nursing, a social and humanistic health care practice discipline, which is structured in the science and art of prevention, diagnosis and treatment of human beings with knowledge, skill and care. This premise has mobilized nursing theorists to produce specific knowledge in teaching, research and care, seeking to develop, test and apply care technologies and instruments that guide the choice for better practices which are sensitive to the singularity of each individual and that person's life context and overall well being. To transfer this knowledge into the professional practice, it is critical that the nurses develop strong intellectual abilities as well as technical scientific, ethical, aesthetic, and humanistic skills. Today and into the future the best nurses will demonstrate the ability to investigate, diagnose, set goals and intervene based on evidence, yet without losing the holistic perspective. Critical holistic thinking is most clearly evident in the nursing diagnosis process because \"getting the problem right\" is the first and most important step in solving the problem. The application of strong critical thinking, in conjunction with good clinical data and solid knowledge, is essential if an accurate diagnosis is to be made, a diagnosis which takes all the relevant factors into consideration. Critical thinking is the process of forming a reflective judgment concerning what to believe or what to do in any given context. It is reflective, meaning that it is open to self monitoring and self correction. It applies cognitive skills, including analysis, inference, evaluation, interpretation, and explanation. More than skills alone, strong critical thinking is driven by the consistent internal motivation to apply those skills. An orientation toward truth seeking, inquisitiveness, confidence in reasoning, organization, foresight, and maturity of judgment characterizes strong critical thinkers. Individuals are capable of developing into strong critical thinkers, and so are groups or teams which work together on problems. Holistic Critical Thinking in the Nursing Diagnostic Process", "author_names": [ "Peter A Facione", "Maria da Graca de Oliveira Crossetti", "Fernando Riegel" ], "corpus_id": 4794112, "doc_id": "4794112", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Holistic Critical Thinking in the Nursing Diagnostic Process.", "venue": "Revista gaucha de enfermagem", "year": 2017 }, { "abstract": "Logistics research in the area of performance measurement continues to receive attention from a variety of perspectives. One well received perspective is that of efficiency. Data envelopment analysis is a well studied analytical tool to identify best practicing efficient operating units of the firm. But a theoretical linkage remains absent from the literature. Drawing upon theoretical perspectives of organization search and knowledge transfer, this study identifies conditions in which suitable role models (according to reference set analysis) may be unrealistic and thus warrant refinements. Ironically, it is through the existence of these particular analytical tools that we are able to develop and then test our framework and illustrate the practical implications. Moreover, this study is ideally suited to illustrating how the methodology is widely applicable among the growing number of multi unit multi market (MUMM) firms around the world, particularly given the diffusion of sophisticated performance information gathering technologies widely used in today's information age.", "author_names": [ "Anthony D Ross", "Stewart R Miller", "Mason A Carpenter" ], "corpus_id": 153570879, "doc_id": "153570879", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "When methods and theories collide: Toward a better understanding of improving unit performance in a multimarket firm", "venue": "", "year": 2010 } ]

[ { "abstract": "Wide bandgap oxide semiconductors constitute a unique class of materials that combine properties of electrical conductivity and optical transparency. They are being widely used as key materials in optoelectronic device applications, including flat panel displays, solar cells, OLED, and emerging flexible and transparent electronics. In this article, an up to date review on both the fundamental understanding of materials physics of oxide semiconductors, and recent research progress on design of new materials and high performing thin film transistor (TFT) devices in the context of fundamental understanding is presented. In particular, an in depth overview is first provided on current understanding of the electronic structures, defect and doping chemistry, optical and transport properties of oxide semiconductors, which provide essential guiding principles for new material design and device optimization. With these principles, recent advances in design of p type oxide semiconductors, new approaches for achieving cost effective transparent (flexible) electrodes, and the creation of high mobility 2D electron gas (2DEG) at oxide surfaces and interfaces with a wealth of fascinating physical properties of great potential for novel device design are then reviewed. Finally, recent progress and perspective of oxide TFT based on new oxide semiconductors, 2DEG, and low temperature solution processed oxide semiconductor for flexible electronics will be reviewed.", "author_names": [ "Jueli Shi", "Jiaye Zhang", "Luhan Yang", "Mei Qu", "Dong-chen Qi", "Kelvin H L Zhang" ], "corpus_id": 232762314, "doc_id": "232762314", "n_citations": 5, "n_key_citations": 0, "score": 1, "title": "Wide Bandgap Oxide Semiconductors: from Materials Physics to Optoelectronic Devices.", "venue": "Advanced materials", "year": 2021 }, { "abstract": "II oxides wide bandgap semiconductor, including the beryllium oxide (BeO) magnesium oxide (MgO) zinc oxide (ZnO) have large exciton binding energy (ZnO 60 meV, MgO 80 meV) high optical gain (ZnO 300 cm 1) and wide tunable band gap (3.37 eV ZnO, MgO 7.8 eV, BeO 10.6 eV) which are the advantages of achieving low threshold laser devices in the ultraviolet wavelength. It is also one of the important candidates to replace the traditional gas arc lamp (such as mercury lamp, deuterium lamp, excimer lamp, xenon lamp etc. as the source of deep ultraviolet and even vacuum ultraviolet. Although, during the past decades, the ZnO based pn homojunction devices have made great progress in the near UV electroluminescence, but as the band gap broadens, the acceptor (or donor) ionization energy becomes higher (On the order of hundreds meV) which causing the room temperature equivalent thermal energy (26 meV) cannot make the impurities ionizing effectively. In addition, the self compensation effect in the doping process further weakens the carrier yield. These above drawbacks have become the bottleneck that hinders II oxides wide bandgap semiconductor from achieving ultraviolet laser devices and expanding to shorter wavelengths, and are also a common problem faced by other wide bandgap semiconductor materials. The regulation of the electrical and luminescent properties of materials often depends on the control of critical defect states. The rich point defects and their combination types make the II oxides wide bandgap semiconductors an important platform for studying defect physics. For the identification and characterization of specific point defects, it is expected to discover and further construct shallower defect states, which will provide a basis for the regulation of electrical performance. In this paper, recent research results of II oxides wide bandgap semiconductors will be described from three aspects: high quality epitaxial growth, impurity and point defects, p type doping and ultraviolet electroluminescence. Through the overview of related research works, II oxides wide bandgap semiconductors are clarified as deep ultraviolet light sources materials. Meanwhile, indicates that the key to the regulation of electrical performance in the future lies in the regulation of point defects.", "author_names": [ "Xie Xiu-hua", "Liao Bing-hui", "Zhang Zhen-zhong", "Liu Lei", "Liu Ke-Wei", "Shan Chong-Xin", "Shen De-zhen" ], "corpus_id": 235118407, "doc_id": "235118407", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Point defects: key issues for II oxides wide bandgap semiconductors development", "venue": "", "year": 2019 }, { "abstract": "Energy has emerged to be a global concern as the world confronts the challenges of population growth, climate change, economic recovery, energy affordability. To overcome the energy crisis, people need to work with both hands: use one hand to make a transition from fossil fuels to clean, renewable energy and the other hand to cut down energy consumption by developing energy efficient devices and systems. In this dissertation, I focus my research to tackle these problems using wide bandgap semiconductors, III nitride (GaN and InGaN) and zinc oxide (ZnO) as basic materials due to their unique optoelectronic properties. Material growth III nitride using MOCVD and ZnO using hydrothermal solution synthesis are studied. For renewable energy application, I developed InGaN/GaN MQW photoelectrode for spontaneous photoelectrochemical (PEC) water splitting and hydrogen fuel generation. The InGaN/ GaN MQW structure provides sufficient photovoltage to split water. Using this single photoelectrode, a current density of 0.16 mA*cm 2 and a peak solar to hydrogen conversion efficiency of 0.2% are obtained at zero external bias. Two schemes are studied to improve the photoelectrode efficiency and stability. By adding NiOx oxygen evolution catalyst, the overall solar to hydrogen conversion efficiency is improved to 0.64% at zero bias. The stability of photoelectrode is also much improved and photocurrent reduction of 4.5% in 12 hours is achieved. In order to further boost the performance of the photoelectrode, plasmonic metal nanostructures are created for enhanced light absorption. The conversion efficiency is improved up to 0.93% For energy saving application, I demonstrated a novel lighting technology based on nano materials ZnO nanowires and carbon nanotubes. The novel design, junctionless light emitting device, consists of a carbon nanotube array cathode for electron field emission and a ZnO nanowire array light emitting anode. High energy electrons directly bombard onto nanowires, generate electron hole pairs, which subsequently recombine to emit light. Strong near band edge emission is obtained with a peak at 390 nm. The use of vertical nanowire array as anode offers advantages in increasing the junction area and carrier recombination/photon generation and enhancing the light extraction efficiency. This approach utilizes the unique properties of nanoscale materials and opens an area for efficient lighting technologies in the future", "author_names": [ "Muchuan Yang" ], "corpus_id": 138967199, "doc_id": "138967199", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Wide bandgap semiconductors for energy efficiency and renewable energy applications", "venue": "", "year": 2014 }, { "abstract": "Nitrides feature many interesting properties, such as a wide range of bandgaps suitable for optoelectronic devices including light emitting diodes (LEDs) and piezoelectric response used in microelectromechanical systems (MEMS) Nitrides are also significantly underexplored compared to oxides and other chemistries, with many being thermochemically metastable, sparking interest from a basic science point of view. This paper reports on experimental and computational exploration of the Mg Sb N material system, featuring both metastable materials and interesting semiconducting properties. Using sputter deposition, we discovered a new Mg2SbN3 nitride with a wurtzite derived crystal structure and synthesized the antimonide nitride Mg3SbN with an antiperovskite crystal structure for the first time in thin film form. Theoretical calculations indicate that Mg2SbN3 is metastable and has properties relevant to LEDs and MEMS, whereas Mg3SbN has a large dielectric constant (28\\epsilon_0) and low hole effective masses (0.9m_0) of interest for photovoltaic solar cell absorbers. The experimental solar matched 1.3 eV optical absorption onset of the Mg3SbN antiperovskite agrees with the theoretical prediction (1.3 eV direct, 1.1 eV indirect) and with the measurements of room temperature near bandgap photoluminescence. These results make an important contribution towards understanding semiconductor properties and chemical trends in the Mg Sb N materials system, paving the way to future practical applications of these novel materials.", "author_names": [ "Karen N Heinselman", "Stephan Lany", "John D Perkins", "Kevin R Talley", "Andriy Zakutayev" ], "corpus_id": 166228004, "doc_id": "166228004", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Thin Film Synthesis of Semiconductors in the Mg Sb N Materials System", "venue": "Chemistry of Materials", "year": 2019 }, { "abstract": "b Ga2O3 is an emerging, ultra wide bandgap (energy gap of 4.85 eV) transparent semiconducting oxide (TSO) which attracted recently much scientific and technological attention. Unique properties of that compound combined with its advanced development in growth and characterization place b Ga2O3 in the frontline of future applications in electronics (Schottky barrier diodes, field effect transistors) optoelectronics (solar and visible blind photodetectors, flame detectors, light emitting diodes) and sensing systems (gas sensors, nuclear radiation detectors) A capability of growing large bulk single crystals directly from the melt and epi layers by a diversity of epitaxial techniques, as well as explored material properties and underlying physics, define a solid background for a device fabrication, which, indeed, has been boosted in recent years. This required, however, enormous efforts in different areas of science and technology that constitutes a chain linking together engineering, metrology and theory. The present review includes material preparation (bulk crystals, epi layers, surfaces) an exploration of optical, electrical, thermal and mechanical properties, as well as device design fabrication with resulted functionality suitable for different fields of applications. The review summarizes all of these aspects of b Ga2O3 at the research level that spans from the material preparation through characterization to final devices.", "author_names": [ "Zbigniew Galazka" ], "corpus_id": 104934626, "doc_id": "104934626", "n_citations": 111, "n_key_citations": 2, "score": 0, "title": "b Ga2O3 for wide bandgap electronics and optoelectronics", "venue": "", "year": 2018 }, { "abstract": "Ultraviolet (UV) photodetectors (PDs) as pivotal elements in modern optoelectronic devices, have attracted increasing research interest in recent years because of their wide applications both in civil and military fields such as confidential space communication, flame detection, imaging, and missile warning systems. Gallium oxide is a desirable candidate for deep UV photodetection due to its suitable ultrawide bandgap 4.5 to 4.9 eV) without the necessity of alloying process. It is reported that crystalline gallium oxide has five phases (a, b, g, d and e) and b phase is the most stable. Many kinds of crystalline gallium oxide UV PDs including bulk, thin films, and nanostructures have been demonstrated and summarized in several review articles recently. According to common understanding of semiconductors, properties of crystalline materials with limited defects are usually superior compared with their amorphous counterparts. For example, the performance of solar cells or transistors using crystalline Si is better than amorphous ones because the carrier mobility of crystalline Si is about 200 cm V 1 s which is much higher than the value of amorphous Si 1 cm V 1 s However, things have been changed in 2004, since the first report of high performance flexible thin film transistors (TFTs) based on amorphous InGaZnO (a IGZO) a transparent amorphous oxide semiconductor (TAOS) with electron mobility as high as 10 cm V 1 s From then on, TAOS TFTs as well as the fundamental material science have been extensively investigated and now they are being used in commercial large area flat panel displays. According to previous researches related with a IGZO, Ga element is a necessary stabilizer in the amorphous structure since gallium oxide will not crystallize unless the substrate temperature is higher enough, whereas indium oxide and zinc oxide tend to crystallize readily even at room temperature (RT) It indicates amorphous gallium oxide (a GaOx) could be realized more easily compared with indium oxide and zinc oxide. As a matter of fact, a GaOx has also attracted a great deal of attention due to its wide bandgap and high breakdown field strength. At the earlier stage, a GaOx thin films were mainly used as a dielectric layer or a passivation layer in microelectronic devices and solar cells. In 2017, three groups reported solar blind UV PDs using a GaOx thin films almost simultaneously. It is quite interesting that the performance of UV PD using a GaOx is comparable or even better than its crystalline counterpart. Except for UV PDs, a GaOx materials also have extensive applications in areas of solar cells, phosphors, resistance random access memories (RRAMs) gas sensors, and radiation detectors. These versatile applications together with the fact that scalable a GaOx can be easily prepared on almost any substrates make it appealing for flexible electronics and giant microelectronics. Great attention has been paid to this cost effective material, evidenced by the increased number of publications retrieved with the key word of \"amorphous Ga2O3,\" as shown in Figure 1. To further understand the material properties of a GaOx and construct superior UV PDs, it is necessary to summarize the progresses on a GaOx materials and devices. In this Review, we will Dr. H. Liang, Z. Han, Prof. Z. Mei Songshan Lake Materials Laboratory Dongguan, Guangdong 523808, China E mail: hlliang@iphy.ac.cn; zxmei@iphy.ac.cn Dr. H. Liang, Z. Han, Prof. Z. Mei Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190, China Z. Han School of Physical Sciences University of Chinese Academy of Sciences Beijing 100049, China", "author_names": [ "Huili Liang", "Zuyin Han", "Zengxia Mei" ], "corpus_id": 224998347, "doc_id": "224998347", "n_citations": 2, "n_key_citations": 1, "score": 0, "title": "Recent Progress of Deep Ultraviolet Photodetectors using Amorphous Gallium Oxide Thin Films", "venue": "physica status solidi (a)", "year": 2020 }, { "abstract": "In this article density functional theory (DFT) approach is utilized to study the crystal structure and optoelectronic properties of the double perovskites Ba2MM'O6 (M= Sc, Y, La; M' Nb, Ta) in cubic phase with space group Fm 3m (No. 225) Generalized gradient approximation along with modified Becke Johnson exchange potential is used to investigate the optoelectronic properties of these transition metal based compounds. The calculated electronic band profiles show that all these oxides are wide and direct bandgap semiconductors. The bandgaps of the oxides ranges from 3.8 to 4.7 eV. Optical properties demonstrate many aspects due to their potential applications as dielectric materials and in optoelectronic devices.", "author_names": [ "Shahid Mehmood", "Zahid Ali" ], "corpus_id": 221494221, "doc_id": "221494221", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Optoelectronic properties of the double perovskites Ba2MM'O6 (M= Sc, Y, La; M' Nb, Ta) by modified Becke Johnson potential", "venue": "Other Conferences", "year": 2020 }, { "abstract": "The UV community for the fourth time took part in the International Workshop on Ultraviolet Materials and Devices (IWUMD4) which was organized in September 2019 by the Ioffe Institute, St. Petersburg, Russia. This event, following the successful meetings in Beijing, China (2016) Fukuoka, Japan (2017) Kunming, China (2018) was intended to show new horizons beyond the UV blue LEDs based on wide bandgap III Nitrides. Material science, modeling and technology for the \"UV gap\" (200 300 nm) are at the frontier of applied physics. The studies are aimed at developing devices for such areas as medicine for human safely disinfection and rapid detection of viral threats, communication for noise protected and solar blind UV optical communication, nanotechnology for high resolution photolithography and for many other applications in the field of biology, pharmaceuticals and forensics. The Workshop was attended by 125 scientists from 15 coun tries, including half from Asia and half from Europe and the DOI: 10.1002/pssa.202000378 USA. The Program was very eventful and included 2 plenary talks by Prof. Chris G. Van de Walle (UCSB) and Prof. Michael Kneissl (TU Berlin&FBH) 4 keynotes, and 25 invited papers, as well as 35 oral presentations and 36 poster contributions displayed during two poster sessions. Prior to Workshop, the Tutorials on the basic properties of wide gap semiconductor materials and nanostructures with lectures of outstanding experts in this field were held for one and a half days. The scope of the presentations at the Workshop was quite wide. Besides the fundamental properties of wide gap semiconductor materials and nanostructures, their optical and structural characterization and applications, it highlighted new trends, such as the growth, basic properties and applications of Ga2O3 and physics of BN from bulk to 2D materials. This issue features selected reports from the Workshop participants. Recent results on the manufacture of high quality templates of the nitrides and oxides by using different technological approaches are presented. The fundamental problems of low dimensional heterostructures and the techno logical challenges of various epitaxial growth methods, such as molecular beam epitaxy and metalorganic chemical vapor deposition, are examined in detail to further improve the quan tum efficiency and output power of UV light emitting devices. A study of the optical properties of AlGaN layers and laser diode heterostructures are presented, which elucidate the nature and characteristics of spontaneous and stimulated emis sions in AlGaN laser structures. In addition, the fabrication and radiation of GaN hexagonal microcavities are discussed. A variety of topics reflects the wide range of interests of the Workshop. The Editors would like to thank all the members of the International Advisory and Program Committees for their encouragement and great help during the Workshop organization. We are grateful to the referees for their efforts and time devoted to the paper review process. We owe our best thanks to the official partners and sponsors of the workshop, as well as all participants at the symposium exhibition. Finally, we would like to express our sincere gratitude to Dr. Stefan Hildebrandt and the production team of physica status solidi for their friendly assistance and collaboration in the editorial process. The next 5th International Workshop on Ultraviolet Materials and Devices (IWUMD5) is planned to be held in November 2020 in Jeju, Korea. We wish the organizers a gorgeous and successful meeting.", "author_names": [ "Stefan Ivanov", "Tatiana V Shubina", "Valentin N Jmerik", "Bernard Gil" ], "corpus_id": 225197166, "doc_id": "225197166", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Ultraviolet Materials and Devices", "venue": "", "year": 2020 }, { "abstract": "II VI semiconductors (compounds formed by group IIB metallic elements (Cd, Zn, and Hg) with group VI nonmetallic elements (O, S, Se, and Te) have aroused intense interest in research and development. Because of its prominent optoelectronic properties for applications such as in thin film photovoltaics, nanophotodetectors, and lasers, cadmium sulfide (CdS) has been in the spotlight. Due to its unique properties and applications in nanoscience and nanotechnology as phosphors, sensors, and optoelectronic devices, zinc oxide (ZnO) has drawn the attention as a strategic and safe technological material. Moreover, on account of their unique capability of behaving as both wide bandgap (1.5 3.5 eV) and narrow bandgap (0 1.5 eV) materials, II VI compounds are utilized in applications such as photoconductors, ultrasonic transducers, and Hall effect devices. Mercury telluride (HgTe) has been placed in the foreground due to its very high Hall mobility and mobility ratio. In this chapter, a description of the processing techniques, properties, and applications of CdS, ZnO, and HgTe (and related ternary and quaternary compounds) both as thin films and nanostructured forms, is detailed. Studies on the resulting materials morphologies and optoelectronic properties from previous works by other authors as well as from the authors' investigations mainly focusing on CdS prepared by the chemical bath deposition (CBD) technique, are presented. The chapter is also intended to provide the readers with both seminal and recent bibliographical references on the topics.", "author_names": [ "Bindu Krishnan", "Sadasivan Shaji", "M C Acosta-Enriquez", "E B Acosta-Enriquez", "R Castillo-Ortega", "Ma E Zayas", "S Jesus Castillo", "Ilaria Elena Palama", "E D'Amone", "Martin Ignacio Pech-Canul", "Stefania D'Amone", "Barbara Cortese" ], "corpus_id": 139349928, "doc_id": "139349928", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Group II VI Semiconductors", "venue": "", "year": 2019 }, { "abstract": "Wide bandgap semiconductors such as SiC, GaN and related alloys, BN and related alloys, ZnGeSiN2, ZnO, and others continue to find new applications in solid state lighting, sensors, filters, high power electronics, biological detection, and spintronics. Improved bulk and epitaxial growth, processing, device design, and understanding of the physics of transport in heterostructures are all necessary for realization of these new technologies. The papers in this book span a range of subjects from material growth and characterization to the processing and application of devices in the electronic, as well as the optoelectronic, fields. Topics include: special invited papers; growth, processing and devices; novel applications for wide bandgap semiconductors; oxides, heterostructures and devices; processing and devices and emerging areas.", "author_names": [ "Jen-Inn Chyi", "Stephen J Pearton", "Jung Jae Han", "Albert G Baca", "W H Chang" ], "corpus_id": 107511557, "doc_id": "107511557", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "New applications for wide bandgap semiconductors symposium held April 22 24, 2003, San Francisco, California, U.S.A.", "venue": "", "year": 2003 } ]

[ { "abstract": "In this paper, we have performed an empirical evaluation of several analog trimming methodologies used for Semiconductor Manufacturing Wafer Sort testing. The study shows that a dynamic trimming approach is the best among those evaluated. The other methodologies evaluated in this paper suffer for several weaknesses such as: 1) unwanted yield loss when the actual least significant bit (LSB) equivalent value or weight drifts from the characterized value due to fab process variations, 2) higher test time leading to elevated cost of test and delivery cycle time degradation, and 3) continual need for Test Program modifications to account for fab process shifts. Finally, a review of basic trimming principles will be covered. We will discuss the need for parameter trimming in the semiconductor industry along with common analog trimming algorithms and review actual wafer test data at wafer probe.", "author_names": [ "Rex F Bullag", "Rolando C Ortega", "Sorina B Bullag" ], "corpus_id": 9130899, "doc_id": "9130899", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Adaptive trimming test approach The efficient way on trimming analog trimmed devices at wafer sort", "venue": "36th International Electronics Manufacturing Technology Conference", "year": 2014 }, { "abstract": "Wafer level packages continue to see strong growth driven by mobile phones, portable players, digital cameras and tablets. All these devices use small form factor and low profile packages such as a wafer level chip scale package (WLCSP) as it fits the requirements. Conventional flip chip die with solder bump is growing due to the increasing number of new design packages converting from wire bond and new flip chip interconnects such as copper pillar and micro bump are growing as a result of strong demand in 3D stacked ICs. Both WLCSP and flip chip need to be electrically tested in wafer format at some point in the assembly process, either as a Known Good Die (KGD) in 3D ICs or an end product that goes into the PCB of an electronic gadget. Wafer sort or wafer level testing was once considered as a method to save packaging cost as this process sorts out bad die before it is assembled into a package. However, today wafer sort or wafer level testing is an important process for yield enhancement of flip chip packages and a final test requirement for WLCSPs. The challenge of wafer level testing has grown significantly due to the increasing complexity of the die or packages. The current technology started to see limitations in hardware and tools. This paper investigates the challenges facing wafer level testing as well as examining the solutions available to overcome these challenges, identifying the gaps and additional innovation needed to overcome these challenges. INTRODUCTION For many years, wafer level testing or wafer sort was employed for two reasons. Firstly, it is to sort out bad dies to prevent them from being assembled into the final package and this would save the cost of packaging. Secondly, the purpose of wafer level testing is to provide yield feedback to the wafer fab in time to control the wafer fabrication process [1] These two purposes are still valid today. However, as packaging technology advances, wafer level packages such as flip chip and WLCSP changes the wafer test requirements not only for yield enhancement of the final package, but also full coverage of testing as it takes the final form of the end package. These bumped types of wafers need to be contacting at solder bumps instead of pads during test. It seems relatively easy compared to contacting pads as bumps are larger in size and wider in pitch; however, the real situation is more complex as the challenges of testing these bumped chips are different. Wafer Level Packaging (WLP) refers to the technology of packaging an integrated circuit at wafer level and it takes many forms. There are WLCSP, flip chip dies built into flip chip or 3D packages and all these dies or packages need wafer level testing. PACKAGES REQUIRE WAFER LEVEL TESTING The traditional functions of a semiconductor device package are to provide environmental protection for the die built in it. However, this need of protection becomes less important with the short expected life of the IC and advancement in material used in building the wafer level package. Wafer Level Chip Scale Packaging (WLCSP) as its name \"Chipscale package\" implies, is a wafer level packaged die with grid array bumps at pitches of 0.4mm and above. This bumped integrated circuits package goes directly onto printed circuit boards of end electronic products such as mobile phones which are one of the fastest growing package types in the semiconductor industry. Fabrication and testing of WLCSPs are done at the wafer level. As the manufacturing cost drops with increased wafer size and reduced die size, cost competitiveness becomes a main motivation to replace traditional QFN packages in mobile devices with WLCSPs. WLCSP is not new; it started with small size and low I/O a decade ago till today with high pin counts and larger package size as shown in below figure 1. In the extension of WLCSP, fan out wafer level technology overcomes interconnect density limitations on PCBs and Figure 1: Large WLCSP with I/O above 100 reduces the need for bump interconnects [2] One typical example of fan out technology is embedded wafer level BGA (eWLB) show in below figure 2. Flip chip and wire bond are the two standard processes to connect the die to a substrate. The flip chip device continues to see strong growth with an increasing number of new designs converting from wire bond. The reasons for the conversion can be attributed to the advantages of its thermal and electrical properties, lower cost and ability to support high I/O count with a smaller package relative to the die size; as shown in figure 3 below. The connection area required for flip chip is much smaller than what is required for wire bonding because all the I/Os from the chip are connected through the bottom. [3] Flip chip packaging uses area array solder bump configurations and its typical bump pitch is 150mm. Figure 4 shows examples of final flip chip packages in the form of fcBGA and fcFBGA that are in high volume manufacturing now. As the need for increased I/O signal connections grow; the bump pitch has to decrease. In order to maintain standoff height with decreasing pitch, a solid column type bump has to be employed and this is copper column bump. Flip chip with copper column bump is expected to see greater demand as the need the fine pitch solutions increase. There are two approaches for copper column bumps as shown in figure 5 below: one with a solder cap and the other without. Copper column bump pitch can be as low as 40mm and this makes testing them very difficult. 3D packaging is driven by wireless and consumer products that require package level functional integration in a small footprint, low profile and lower in cost. 3D packages come in many different forms. For some, flip chip dies are used in the package and certainly these dies must be known good die (KGD) to ensure the end package quality. Figure 6 shows an example of a 3D package with flip chip die. Figure 2: Embedded Wafer Level BGA (eWLB) Figure 3: Flip chip connection area compared to wire bond connection area Figure 4: Flip Chip packages Figure 5: Copper column bump. (Top photo shows solder cap version) NEW CHALLENGES IN WAFER LEVEL TESTING The paradigm for wafer level test is changing rapidly. The original intent of final yield enhancement and feedback to the wafer fab for process control for performance wafer sort has expanded. With new package or die types needed to test in wafer level, different challenges have surfaced. Comparing package handling in a test handler where wafers are effectively all the same, it would appear that the handling of wafers would be an easier task. The actual handling, though, is probably more difficult since wafers are extremely fragile and damaging even one wafer is unacceptable due to the large number of valuable dies lost. The handling equipment or prober needs to be extremely precise and intelligent to handle these fragile wafers. Wafer level test handling equipment or probers face significant technical challenges in different markets or wafer types. One of the common issues is the need for high parallelism test. For high parallelism requirements, the prober needs to have accurate alignment capability and very high force test chuck for presenting the wafer to probe card for contacting. There is even a need for full wafer contact of a 300mm wafer with thousands of solder bumps and it becomes a challenge for providing increasing insertion force without damaging the fragile wafer. In wafer handling, different types of wafers need to be processed in the same prober. We see thin wafers at high warpage that need to be tested. These wafers go through back grinding to the required end thickness before wafer testing on the prober. Typically a standard prober can handle up to 350mm thickness. For wafers thinner than 350mm, there is an increased tendency to warp badly and make handling in a prober very difficult. In this case, a special tool or kit will be needed to handle this type of thin wafer. However, any wafer thickness of less than 150mm is still a challenge for the prober to handle. With the new type of wafers such as eWLB gaining popularity, the prober now needs to handle wafers with different surfaces or materials. These eWLB wafers are different from normal silicon wafers as the backside of the wafers are a mold compound and they tend to have a higher warpage level with a similar thickness as silicon wafer as shown in figure 7 The above mentioned challenges need to be overcome with good handling equipment. Probers now need to have capability and/or options as listed below: High force chuck for high parallelism Wafer handling arm and chuck to handle thin and warped wafers Chuck that can handle different material of wafer such as eWLB wafers with molded material at backside of the wafer Intelligence optical alignment for fine pitch bumps High speed wafer changing and indexing As the requirements get more stringent, probers will need to continue improving to meet all the new requirements. The overall end user would need a flexible and cost effective prober to handle different requirements and situations. PROBE CONTACT CHALLENGES As the need for increased I/O signal connections grow, the bump pitch has to decrease and maintain a greater standoff height. A solid column type of bump is created either in solid copper column or with an added solder cap. Fine pitch is always a challenge for probe card geometry and precision. A prober that handles fine pitch wafers needs the precision to achieve an accurate probing. Currently, flip chip die with 150mm pitch is in mass production without Figure 6: Example of 3D package Figure 7: eWLB warpage condition issue. Typically this type of bumped wafer uses a vertical probe card with buckling beam type of contact pins. As the pitch of copper column bump scales below 100mm, this type of vertical probe card design cannot scale down to the required pitch. Advanced probe cards with MEMS technology will be need", "author_names": [ "Lim Kok Hwa", "Andy Chee" ], "corpus_id": 8023258, "doc_id": "8023258", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "\" Wafer Level Testing Challenges for Flip Chip and Wafer Level Packages \"", "venue": "", "year": 2013 }, { "abstract": "In Semiconductor Manufacturing, inline Inspection monitoring by Brightfield and Darkfield scan tool platform is a 2nd line of defence to detect abnormal events to prevent defectivity escape to Wafer Sort or Assembly Test. Early detection and good process tool coverage are essential to the quality of wafers. These have to be balanced with competitive cycle time and cost. There are many newer scan tool, software and manufacturing systems available today that can optimize this sampling monitoring. As a legacy 200mm foundry wafer fab, system upgrade may not be feasible or can be expensive. As a result, an innovative solution had to be developed in order to stay relevant in the semiconductor industry. This paper introduces an inline inspection sampling Artificial Intelligent (AI) methodology to ensure maximum process tool scan coverage without additional CAPEX cost getting more out from the same capacity; getting more coverage with same scan capacity and improve line of defence.", "author_names": [ "Ang Kian Huat", "Jonathan Boon Kwang Yap", "Ning Ning", "Tan Siew Fen", "Shakar Govindasamy Mani", "Myla Terredano" ], "corpus_id": 67875057, "doc_id": "67875057", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Smart Sampling Methodology for Yield Defect Inspection in a 200mm Foundry Wafer Fab", "venue": "2018 International Symposium on Semiconductor Manufacturing (ISSM)", "year": 2018 }, { "abstract": "Abstract This paper discusses two airborne molecular contaminants (AMCs) decontamination and control solutions for Front Opening Unified Pods (FOUPs) namely, inert gas purge and aqueous wet cleaning, and the effect these processes have on HF volatile acid cross contamination of Cu coated wafers stored inside FOUPs of different polymer types, polycarbonate (PC) polycarbonate carbon powder (PCCP) and Entegris Barrier Materials (EBMCNT) The obtained results show that continuous FOUP purge appears to be an effective way to control HF cross contamination, to guarantee an optimum yield thanks to low humidity, and to clean chemically the environment from AMCs. Wet cleaning is an option after a high contaminating process. Wet cleaning removes the acid contamination from within the polymer near the surface, and removal efficiency is dependent on queue time; a higher removal rate is expected with a shorter queue time. The EBMCNT FOUP is the best of the materials tested in terms of HF contamination transfer reduction. Finally, numerical simulation (using a simple membrane model) shows that irreversible contamination results from the accumulation of the residual contamination in the polymer.", "author_names": [ "Paola Gonzalez-Aguirre", "Herve Fontaine", "Sung In Moon", "Carlos Beitia", "Jorgen Lundgren", "Jim Ohlsen" ], "corpus_id": 139221592, "doc_id": "139221592", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "FOUP decontamination solutions to control AMCs in semiconductor fabs: Gas purge or wet cleaning?", "venue": "", "year": 2018 }, { "abstract": "Semiconductor reliability in applications such as automotive is getting increased attention as design rules shrink to include 1Xnm, semiconductor content per vehicle continues to grow, applications become more critical and reliability requirements tighten. Current automotive requirements stipulate less than one defective part per million (DPPM) Approaches to address reliability include improving design, manufacturing and test. Process control in manufacturing is critical for reliability and includes continuous improvement for reducing process tool defectivity, excursion monitoring of process tools and product lines, golden or best performing tool methods [1] measurement system analysis (MSA) methods and screening. Inline defectivity is known to have an impact on both yield and reliability [2] and defects can impact reliability in one of two ways. Killer defects located in areas that are untested can result in so called Zero Kilometer failures. In other cases, the same types of defects that cause yield loss can also cause latent reliability failures the difference being size, location and density. Latent reliability defects become activated after test and can include defect types such as partial bridges, partial opens, and embedded particles. Current reliability engineering relies on outlier detection rules like parametric part average testing (P PAT) [3] or geographic part average testing (G PAT) both of which are derived from end of line screening data, which is based solely on electrical test data [4] Inline Part Average Testing (I PAT(tm) is enabled by multi channel high speed LED scanning inspection technology and offers an opportunity to apply fab data to reliability engineering. Defect inspection results are analyzed with machine learning (ML) to weigh the defectivity and create a die level defectivity metric allowing the statistical identification of die which are a high reliability risk [5, 6] Two case studies are described. The first case is a feasibility study based on historical fab defectivity data and includes a sample of ~250,000 die, with eight inline defect inspections per wafer, including four front end of line (FEOL) and four back end of line (BEOL) on a high sensitivity broadband inspection system [7, 8] Each defect is assigned a weight based on its impact to various \"ground truth\" indicators. The combined impact of all defects in a given die stacked across all inspections is aggregated into a die level metric. Plotting the die level I PAT metrics for all the die as a Pareto chart allows outliers to be identified using accepted statistical methods [9] I PAT metrics can then be correlated to electrical wafer sort (EWS) yield or fallout rate, specific wafer sort bins, EWS parametric test performance and post burn in electrical test. Of key importance is that wafer test was not used to train the I PAT model, and therefore this method is an independent validation of latent reliability. The second case study focuses on production screening feasibility with multi channel high speed LED scanning, and addresses overkill, or the over inking of potentially good die based on inline defectivity, which is a critical challenge that must be overcome for production implementation [10] Using inspection enabled by high speed LED scanning technology, die screening is a critical component of a comprehensive automotive Zero Defect program. Applications include early detection of fab excursions, feedback for continuous improvement of inline defectivity, feedforward to optimize electrical test methods and screening of die containing possible latent reliability defects. The I PAT methodology can be used to enhance standard end of line outlier detection rules such as P PAT [3] which is based solely on parametric testing.", "author_names": [ "John C Robinson", "Kara Sherman", "Dave W Price", "Jay Rathert" ], "corpus_id": 215789934, "doc_id": "215789934", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Inline Part Average Testing (I PAT) for automotive die reliability", "venue": "Advanced Lithography", "year": 2020 }, { "abstract": "Typical usage of test wafers (TW) in semiconductor manufacturing involves testing and development of new processes, equipment qualification, and process monitoring activities. A 300 mm fab can potentially spend millions of dollars each year purchasing test wafers. Over the years, improvements in TW management systems have led to a reduction in cost by enabling better inventory control. However, even with the increased level of automation of 300 mm fabs, the TW management process still leaves much to be automated. In this paper, we describe an automated TW management system and the performance benefits derived from its usage.", "author_names": [ "Anam Faruqi", "Raymond Goss", "Diwas Adhikari", "Thomas Kowtsch" ], "corpus_id": 30708251, "doc_id": "30708251", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Test Wafer Management and Automated Wafer Sorting", "venue": "2008 IEEE/SEMI Advanced Semiconductor Manufacturing Conference", "year": 2008 }, { "abstract": "Wafer Level Reliability (WLR) programs have been active in many semiconductor companies since the mid 1980's. Test structures are designed to accelerate known reliability failure mechanisms (similar to ET structures for parametric testing) Large samples of these test structures are packaged and tested to determine reliability failure rates. These WLR programs typically focus on electromigration (EM) hot carrier, and TDDB testing of packaged parts. National Semiconductor has developed and implemented a WLR program which differs from the traditional approach. Wafer manufacturing personnel need to know which people, equipment, or process variables need to be better controlled to prevent reliability problems in the field. They also need faster feedback. Our WLR program looked at these issues and designed a more practical approach to eliminating fab related reliability problems. Wafers, not packaged parts, are tested in line and at the end of line (before sort test) to provide near real time feedback. We identified our top ten reliability failure mechanisms of concern based on past field failure rates and reliability monitors. WLR test structures and test methods were then designed to measure the effect of wafer fab process variability on reliability risk. Designed experiments were used extensively to correlate fab process monitors, WLR test results, and reliability test results.", "author_names": [ "S Garrard" ], "corpus_id": 109649973, "doc_id": "109649973", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Production implementation of a practical WLR program [wafer level reliability]", "venue": "Proceedings of 1994 IEEE/SEMI Advanced Semiconductor Manufacturing Conference and Workshop (ASMC)", "year": 1994 }, { "abstract": "A semiconductor supply network involves many expensive steps, which have to be executed to serve global markets. The complexity of global capacity planning combined with the large capital expenditures to increase factory capacity makes it important to incorporate optimization methodologies for cost reduction and long term planning. The typical view of a semiconductor supply network consists of layers for wafer fab, sort, assembly, test and demand centers. We present a two stage stochastic integer programming formulation to model a semiconductor supply network. The model makes strategic capacity decisions, (i.e. build factories or outsource) while accounting for the uncertainties in demand for multiple products. We use the model not only to analyze how variability in demand affects the make/buy decisions but also to investigate how the correlation between demands of different products affects these strategic decisions. Finally, we demonstrate the value of incorporating demand uncertainty into a decision making scheme.", "author_names": [ "A P Rastogi", "John W Fowler", "W Matthew Carlyle", "Ozgur M Araz", "Arnold Maltz", "Burak Buke" ], "corpus_id": 58908249, "doc_id": "58908249", "n_citations": 35, "n_key_citations": 0, "score": 0, "title": "Supply network capacity planning for semiconductor manufacturing with uncertain demand and correlation in demand considerations", "venue": "", "year": 2011 }, { "abstract": "Integrated circuit manufacturing has major operations of fabrication, sort, assembly, and test. The dynamic behavior of these operations can be modeled in terms of a highly structured queueing network. A model is presented of the components and interactions of wafer movements, processing equipment, and process steps. The model considers multiple process flows, fab organization and layout, and equipment properties such as batch size, process time, failure, and repair distributions. The model is implemented as a discrete event simulation and has been used in a number of case studies concerning realistic factory situations. This simulation model is general and can be used to study many types of discrete manufacturing.", "author_names": [ "Judith E Dayhoff", "Robert W Atherton" ], "corpus_id": 10877727, "doc_id": "10877727", "n_citations": 17, "n_key_citations": 1, "score": 0, "title": "A Model for Wafer Fabrication Dynamics in Integrated Circuit Manufacturing", "venue": "IEEE Transactions on Systems, Man, and Cybernetics", "year": 1987 }, { "abstract": "Acknowledgments. 1. Running Start. About This Book. Some Words to Know. 2. Semiconductor Family Tree. Semiconductor Family Tree. Simple Analog Components. Advanced Analog Components. A/D and D/A Converters. MEMS. Medium Scale Digital Chips. Highly Integrated Digital Chips. 3. How Chips Are Designed. Old Style Design Process. New Style Design Process. Verifying the Design Works. Using Outside IP. Getting to Tape Out and Film. Current Problems and Future Trends. 4. How Chips Are Made. Clean Rooms and Fabs. Developing Technology: Chips and Photography. Silicon Ingots to Start. Polishing the Wafer Smooth. Building the Layer Cake. Laser Surgery: Etching Away the Transistors. Step and Repeat. Etching Bath. Ready for the Metal Round. Testing Phase. Bringing Out the Diamonds. Sorting the Fast from the Merely Good. Wrap It Up. How Many Nanometers in a Micron? Let's Get Small. 5. Business and Markets. Worldwide Production of Semiconductors. Worldwide Consumption of Semiconductors. Military Electronics. The Business of Making Semiconductors. 6. Essential Guide to Microprocessors. Overview of Microprocessors. Microprocessor History and Evolution. What's a Processor Architecture? Microprocessor Anatomy and Gazetteer. What Do 4 Bit, 8 Bit, 16 Bit, and 32 Bit Mean? Performance, Benchmarks, and Gigahertz. What Is Software? Choosing Microprocessors. Microprocessor Future Trends. 7. Essential Guide to Memory Chips. Overview of Memory Chips. Nonvolatile ROM. Volatile RAM. Memory Interfaces. Future Memories. 8. Essential Guide to Custom and Configurable Chips. Overview of Custom Chips. Field Programmable Chips. Custom ASIC Chips. Dynamically Reconfigurable Chips. Intellectual Property Licensing. Future Outlook for Custom Chips. 9. Theory. Digital and Binary Concepts. Gates and Logic Functions. How Transistors Work. About Electrons and Electronics. Appendix: Standard Bodies and Reference. Standards Bodies and Organizations. Conferences and Trade Shows. Other Resources. Glossary. Index.", "author_names": [ "James L Turley" ], "corpus_id": 106548943, "doc_id": "106548943", "n_citations": 66, "n_key_citations": 5, "score": 0, "title": "The Essential Guide to Semiconductors", "venue": "", "year": 2002 } ]

[ { "abstract": "Although photocatalysis has been studied for many years as an attractive way to resolve energy and environmental problems, its principle still remains unclear. Some confusions and misunderstandings exist in photocatalytic studies. This research aims to elaborate some new thoughts on the fundamental principle of semiconductor photocatalysis. Starting from the basic laws of thermodynamics, we first defined the thermodynamic potential of photocatalysis. A concept, the Gibbs potential landscape, was thus then proposed to describe the kinetics of photocatalysis. Photocatalysis is therefore defined as a light driven chemical reaction that still needs heat activation, in that light and heat play their different roles and interact with each other. Photocatalysis should feature an activation energy functioning with both light and heat. The roles of light and heat are correlative and mutually inhibit at both levels of thermodynamics and kinetics, so it is impossible for an intrinsic light heat synergism to happen. Two criteria were further proposed to determine an intrinsic light heat synergism in photocatalysis. Experiments were also carried out to calculate the thermodynamic potential and can agree well with the theory. Experimental results proved that there is no intrinsic light heat synergism, in accordance with our theoretical prediction. This research clarified some misunderstandings and gained some new insights into the nature of photocatalysis; this is important for the discipline of semiconductor photocatalysis.", "author_names": [ "Baoshun Liu", "Haowan Wu", "Ivan P Parkin" ], "corpus_id": 220070261, "doc_id": "220070261", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "New Insights into the Fundamental Principle of Semiconductor Photocatalysis", "venue": "ACS omega", "year": 2020 }, { "abstract": "Abstract Heterogeneous photocatalysis as a sustainable and promising strategy has been intensively investigated for different applications, including solar fuel production and degradation of environmental pollutants. However, it is still challenging to develop highly active, selective, and durable photocatalysts for practical applications. In this chapter, after introducing a brief history of photocatalysis, we first present a comprehensive review on the thermodynamics and dynamics of photocatalysis, which could help the readers deeply understand the fundamental principles of photocatalytic processes. Then, we systematically summarize the basics for the surface/interface science of photocatalysis, including adsorption, surface redox reactions, and interfacial charge separation. Finally, the design principles, modification strategies, and the characterization and evaluation methods of semiconductor photocatalysts are summarized. By addressing these pertinent and important topics in heterogeneous photocatalysis, this chapter is expected to provide a useful reference for researchers in designing and exploring advanced photocatalytic materials for different applications.", "author_names": [ "Xin Li", "Jiaguo Yu", "Chuanjia Jiang" ], "corpus_id": 216478564, "doc_id": "216478564", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Principle and surface science of photocatalysis", "venue": "", "year": 2020 }, { "abstract": "", "author_names": [ "Bunsho Ohtani" ], "corpus_id": 137002612, "doc_id": "137002612", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Principle of Photocatalysis and Design of Active Photocatalysts", "venue": "", "year": 2013 }, { "abstract": "Abstract In the present paper, the electronic structure and the optical properties of metallic and nonmetallic elements doped ZnO were investigated based on the principle of photocatalysis by first principle density functional theory. Element doping shortens the band gap of ZnO. Due to the p type characteristics, Fe, Cu, B and N doping brings impurity states over the Fermi level of ZnO, resulting in the shortening of the band gap, extending the absorption and utilization of solar light and thus enhancing the photocatalytic properties of ZnO. However, no impurity states appear in the band gap of Cd and S doped ZnO due to the intrinsic doping of Cd and S. Further investigations indicate that different doping atoms can indeed alter the near Fermi level density of states (DOS) of ZnO and their electronic structures via substitution of zinc and oxygen atoms. In addition, the optical properties of ZnO are improved after doped with different atoms by comparing with those of pure ZnO. Due to the difference of their outer shell electrons of the doped atoms, the optical absorption properties of the investigated materials are followed as the following order: Fe /B doped ZnO Cu /N doped ZnO Cd /S doped ZnO pure ZnO.", "author_names": [ "Chang Feng", "Zhuoyuan Chen", "Weibing Li", "Fan Zhang", "Xiang-bo Li", "Likun Xu", "Mingxian Sun" ], "corpus_id": 126429382, "doc_id": "126429382", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "First principle calculation of the electronic structures and optical properties of the metallic and nonmetallic elements doped ZnO on the basis of photocatalysis", "venue": "Physica B: Condensed Matter", "year": 2019 }, { "abstract": "Due to the increase of emerging contaminants in water, how to use new treatment technology to make up for the defects of traditional wastewater treatment method has become one of the research hotspots at present. Intimate coupling of photocatalysis and biodegradation (ICPB) as a novel wastewater treatment method, which combines the advantages of biological treatment and photocatalytic reactions, has shown a great potential as a low cost, environmental friendly and sustainable treatment technology. The system mainly consists of photocatalytic materials, porous carriers and biofilm. The key principle of ICPB is to transform bio recalcitrant pollutants into biodegradable products by photocatalysis on the surface of porous carriers. The biodegradable products were mineralized simultaneously through the biofilm inside the carriers. Because of the protection of the carriers, the microorganism can remain active even under the UV light, the mechanical force of water flow or the attack of free radicals. ICPB breaks the traditional concept that photocatalytic reaction and biodegradation must be separated in different reactors, improves the purification capacity of sewage and saves the cost. This review summarizes the recent advances of ICPB photocatalysts, carriers and biofilm being applied, and focuses on the mechanisms and reactor configurations which is particularly novel. Furthermore, the possible ongoing researches on ICPB are also put forward. This review will provide a valuable insight into the design and application of ICPB in environment and energy field.", "author_names": [ "Mingliang Yu", "Jiajia Wang", "Lin Tang", "Chengyang Feng", "Haoyu Liu", "Hongxing Zhang", "Bo Peng", "Zhaoming Chen", "Qingqing Xie" ], "corpus_id": 212718436, "doc_id": "212718436", "n_citations": 30, "n_key_citations": 0, "score": 0, "title": "Intimate coupling of photocatalysis and biodegradation for wastewater treatment: Mechanisms, recent advances and environmental applications.", "venue": "Water research", "year": 2020 }, { "abstract": "Herein, we report on the structural design principle of small molecule organic semiconductors as metal free, pure organic and visible light active photocatalysts. Two series of electron donor and acceptor type organic semiconductor molecules were synthesized to meet crucial requirements, such as 1) absorption range in the visible region, 2) sufficient photoredox potential, and 3) long lifetime of photogenerated excitons. The photocatalytic activity was demonstrated in the intermolecular C H functionalization of electron rich heteroaromates with malonate derivatives. A mechanistic study of the light induced electron transport between the organic photocatalyst, substrate, and the sacrificial agent are described. With their tunable absorption range and defined energy band structure, the small molecule organic semiconductors could offer a new class of metal free and visible light active photocatalysts for chemical reactions.", "author_names": [ "L Wang", "Wei Huang", "Run Li", "Dominik W Gehrig", "Paul W M Blom", "Katharina Landfester", "Kai A I Zhang" ], "corpus_id": 27925752, "doc_id": "27925752", "n_citations": 53, "n_key_citations": 0, "score": 0, "title": "Structural Design Principle of Small Molecule Organic Semiconductors for Metal Free, Visible Light Promoted Photocatalysis.", "venue": "Angewandte Chemie", "year": 2016 }, { "abstract": "In the recent research on photocatalysis, the conversion of green and sustainable technology has received increasing attention due to its potential to solve energy problem in an eco friendly approach. The present review focuses on highly efficient and low cost photocatalysts and various metal free photocatalytic materials that have been designed and developed in recent years for energy conversion and environmental purification as a result of their unique properties and characteristics. This critical review presents the recent crucial applications and progress in metal free photocatalysis, including Water splitting using few layer C 2N, Renewable energy production using photofuelcells, Water purification using UV light, Deodorizing effect, Air purifying effect, Anti fogging and self cleaning as well as Hazardous waste remediation. The review concludes with suggestions for future research topics. It is hoped that this review will facilitate deep level investigation on the subject and provide new opportunities to develop metal free photocatalytic materials with other important applications in the nearest future.", "author_names": [ "Tawakalitu Ajibola", "L Salami", "Alaba Elizabeth Akin-Johnson", "Nafiu Olatunbosun Ashiru", "Kunle Akinluwade", "E A Arikawe" ], "corpus_id": 202914482, "doc_id": "202914482", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Metal Free Photocatalysis: Principle and Application in Energy Conversion and Purification", "venue": "", "year": 2019 }, { "abstract": "With the increasing consumption of fossil energy, more and more refractory pollutants are released into the environment. Using eco friendly ways to treat the pollutants and gain energy is urgently needed. By using microbial fuel cells (MFCs) contaminant degradation and energy recovery can be achieved simultaneously but limited by the finite kinds of degradation of pollutants and the low power production efficiency. To promote the energy productivity and pollutant degradation ability, some researchers are focused on introducing solar energy into the system. Some semiconductors can absorb solar energy and convert it into electricity. Meanwhile, the typical structure of the photo excited semiconductor can improve the performance of contaminant removal. Another ideal energy convention way is the photosynthesis. Some researchers use aquatic microalgae to harness the solar energy and then release the energy by MFC. In addition to producing oxygen and capturing CO2 and other nutrient, the microalga is a promising combination material. The coupling system of MFC and one of semiconductors or microalgae can be seen as microbial photo electro chemical cell (MPEC) systems. The development background and research advances on MPECs are briefly introduced in this chapter. The existing coupling forms of the technology are classified, and the coupling mechanisms of various forms are explained in detail. Finally, the future development of this coupling technology is prospected.", "author_names": [ "Wang Shusen", "Hafiz Muhammad Adeel Sharif", "Haowen Cheng", "Aijie Wang" ], "corpus_id": 134360952, "doc_id": "134360952", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Bioelectrochemical System Integrated with Photocatalysis: Principle and Prospect in Wastewater Treatment", "venue": "", "year": 2019 }, { "abstract": "Self doping by Ti3+ and introducing oxygen vacancies in TiO2 is an important and effective strategy to extend its optical absorption from the UV into the visible region. In this paper, we report the synthesis of a series of Ti3+ self doped TiO2 nanocrystals via a hydrothermal method using TiCl3 and (NH4)2TiF6 as the source of Ti3+ and Ti4+ respectively. The oxidation of Ti3+ can be inhibited by (NH4)2TiF6 based on Le Chatelier's principle. The samples are characterized by X ray diffraction, UV Vis diffuse reflectance spectroscopy, X ray photoelectron spectroscopy, electron paramagnetic resonance, field emission scanning electron microscopy and transmission electron microcopy, respectively. The results indicate that Ti3+ is localized in the bulk of the as prepared TiO2 nanocrystals, rather than on the surface. In comparison with pristine TiO2, the Ti3+ self doped TiO2 nanocrystals exhibit an enhanced photocatalytic activity of 86.3% towards the photodegradation of methylene blue solution under simulated solar light irradiation and 99% under natural solar irradiation. It is found that the molar ratio of Ti4+/Ti3+ used during the synthesis has significant effects on the photocatalytic activity of Ti3+ self doped TiO2 photocatalysts, since the electronic structures of the resulting Ti3+ self doped TiO2 nanocrystals can be finely tuned by changing the ratios. The significantly enhanced photocatalytic activity should be due to the self doping of Ti3+ in TiO2 nanocrystals, which not only increases the optical absorption in the visible light region, but also helps to spatially separate the photogenerated charge carriers.", "author_names": [ "Maoqin Qiu", "Yuan Tian", "Zhangxian Chen", "Zeheng Yang", "Li Wenming", "Kai Wang", "Lei Wang", "Kun Wang", "Weixin Zhang" ], "corpus_id": 100176375, "doc_id": "100176375", "n_citations": 20, "n_key_citations": 3, "score": 0, "title": "Synthesis of Ti3+ self doped TiO2 nanocrystals based on Le Chatelier's principle and their application in solar light photocatalysis", "venue": "", "year": 2016 }, { "abstract": "Hollow structured polyhedral nanostructures of AgI nanoboxes and cube tetrapod Ag/AgI cages have been fabricated through the controlled reaction of I ions with nanocubes and cube tetrapods of AgCl based on the principle of the Kirkendall effect. The Ag0 nanodomains in the source nanoparticles of AgCl:Ag are preserved in the final hollow Ag/AgI cages during the chemical conversion of AgCl to AgI. The obtained hollow cube tetrapod Ag/AgI nanostructures exhibited enhanced light absorption in the visible region and photocatalytic performance towards hydrogen evolution from water reduction and decomposition of organic pollutants, owing to the contribution of the surface plasmon resonance (SPR) effect of silver nanoparticles (nanodomains) The present versatile route can be generalized to the preparation of other inorganic functional materials with hollow interiors for different applications.", "author_names": [ "Changhua An", "Jizhuang Wang", "Junxue Liu", "Shutao Wang", "Qinhui Zhang" ], "corpus_id": 97476446, "doc_id": "97476446", "n_citations": 34, "n_key_citations": 0, "score": 0, "title": "Plasmonic enhancement of photocatalysis over Ag incorporated AgI hollow nanostructures", "venue": "", "year": 2014 } ]

[ { "abstract": "About the Author. Preface. Acknowledgments. Chapter 1: Electrostatic Discharge. 1.1 Electricity and Electrostatics Discharge. 1.2 Fundamental Concepts of ESD Design. 1.3 Time Constants. 1.4 Capacitance, Resistance and Inductance and ESD. 1.5 Rules of Thumb and ESD. 1.6 Lumped versus Distributed Analysis and ESD. 1.7 ESD Metrics and Figures of Merit. 1.8 Twelve Steps to Building an ESD Strategy. 1.9 Summary and Closing Comments. Problems. References. Chapter 2: Design Synthesis. 2.1 Synthesis and Architecture of a Semiconductor Chip for ESD Protection. 2.2 Electrical and Spatial Connectivity. 2.3 ESD, Latchup, and Noise. 2.4 Interface Circuits and ESD Elements. 2.5 ESD Power Clamps Networks. 2.6 ESD Rail to Rail Devices. 2.7 Guard Rings. 2.8 Pads, Floating Pads, and No Connect Pads. 2.9 Structures Under Bond Pads. 2.10 Summary and Closing Comments. Problems. References. Chapter 3: Electrostatic Discharge (ESD) Design: MOSFET Design. 3.1 Basic ESD Design Concepts. 3.2 ESD MOSFET Design: Channel Width. 3.3 ESD MOSFET Design: Contact. 3.4 ESD MOSFET Design: Metal Distribution. 3.5 ESD MOSFET Design: Silicide Masking. 3.6 ESD MOSFET Design: Series Cascode Configurations. 3.7 ESD MOSFET Design: Multi Finger Design Integration of Coupling and Ballasting Techniques. 3.8 ESD MOSFET Design: Enclosed Drain Design Practice. 3.9 ESD MOSFET Interconnect Ballasting Design. 3.10 ESD MOSFET Design: Source and Drain Segmentation. 3.11 Summary and Closing Comments. Problems. References. Chapter 4: Electrostatic Discharge (ESD) Design: Diode Design. 4.1 ESD Diode Design: ESD Basic. 4.2 ESD Diode Design: Anode. 4.3 ESD Diode Design: Interconnect Wiring. 4.4 ESD Diode Design: Polysilicon Bound Diode Designs. 4.5 ESD Diode Design: n Well Diode Design. 4.6 ESD Diode Design: np/p Substrate Diode Design. 4.7 ESD Diode Design: Diode String. 4.8 ESD Diode Design: Triple Well Diodes. 4.9 ESD Design: BiCMOS ESD Design. 4.10 Summary and Closing Comments. Problems. References. Chapter 5: Silicon on Insulator (SOI) ESD Design. 5.1 SOI ESD Basic Concepts. 5.2 SOI ESD Design: MOSFET with Body Contact (T Shaped Layout) 5.3 SOI ESD Design: SOI Lateral Diode Structure. 5.4 SOI ESD Design: Buried Resistors (BR) Elements. 5.5 SOI ESD Design: SOI Dynamic Threshold MOSFET (DTMOS) 5.6 SOI ESD Design: Dual Gate (DG) MOSFETs. 5.7 SOI ESD Design: FinFET Structure. 5.8 SOI ESD Design: Structures in the Bulk Substrate. 5.9 SOI ESD Design: SOI To Bulk Contact Structures. 5.10 Summary and Closing Comments. Problems. References. Chapter 6: Off Chip Drivers (OCD) and ESD. 6.1 Off Chip Drivers (OCD) 6.2 Off Chip Drivers: Mixed Voltage Interface. 6.3 Off Chip Drivers Self Bias Well OCD Networks. 6.4 Off Chip Drivers: Programmable Impedance (PIMP) OCD Networks. 6.5 Off Chip Drivers: Universal OCDs. 6.6 Off Chip Drivers: Gate Array OCD Design. 6.7 Off Chip Drivers: Gate Modulated Networks. 6.8 Off Chip Driver ESD Design: Integration of Coupling and Ballasting Techniques. 6.9 Off Chip Driver ESD Design: Substrate Modulated Resistor Ballasted MOSFET. 6.10 Summary and Closing Comments. Problems. References. Chapter 7: Receiver Circuits and ESD. 7.1 Receivers and ESD. 7.2 Receivers and ESD. 7.3 Receivers and Receiver Evolution. 7.4 Receiver Circuits with Pseudo Zero VT Half Pass Transmission Gates. 7.5 Receiver Circuits with Zero Transmission Gate. 7.6 Receiver Circuits with Bleed Transistors. 7.7 Receiver Circuits with Test Functions. 7.8 Receiver With Schmitt Trigger Feedback Networks. 7.9 Bipolar Transistor Receivers. 7.10 Summary and Closing Comments. Problems. References. Chapter 8: SOI ESD Circuits and Design Integration. 8.1 SOI ESD Design Integration. 8.2 SOI ESD Design: Diode Design. 8.3 SOI ESD Diode Design: Mixed Voltage Interface (MVI) Environments. 8.4 SOI ESD Networks in SOI CPU with Aluminum (Al) Interconnects. 8.5 SOI ESD Design in Copper (Cu) Interconnects. 8.6 SOI ESD Design with Gate Circuitry. 8.7 SOI and Dynamic Threshold ESD Networks. 8.8 SOI Technology and Miscellaneous ESD Issues 8.9 Summary and Closing Comments. Problems. References. Chapter 9: ESD Power Clamps. 9.1 ESD Power Clamp Design Practices. 9.2 ESD Power Clamps: Diode Based. 9.3 ESD Power Clamps: MOSFET Based. 9.4 ESD Power Clamps: Bipolar Based. 9.5 ESD Power Clamps: Silicon Controlled Rectifier Based. 9.6 Summary and Closing Comments. Problems. References. Index.", "author_names": [ "Steven H Voldman" ], "corpus_id": 106854718, "doc_id": "106854718", "n_citations": 112, "n_key_citations": 10, "score": 1, "title": "ESD: Circuits and Devices", "venue": "", "year": 2005 }, { "abstract": "This work describes an ESD empirical simulation flow for circuits containing snapback based devices. Regular ESD transistors SPICE models were combined with empirical models, based on TLP measurements. Behavioral language VerilogA code has been used to add measured characteristics of the transistor at triggering voltage dependent on simulated gate voltage.", "author_names": [ "Efraim Aharoni", "Avi Parvin", "Yosi Vaserman", "Evan Grund" ], "corpus_id": 42777021, "doc_id": "42777021", "n_citations": 6, "n_key_citations": 1, "score": 0, "title": "Empirical ESD simulation flow for ESD protection circuits based on snapback devices", "venue": "2016 38th Electrical Overstress/Electrostatic Discharge Symposium (EOS/ESD)", "year": 2016 }, { "abstract": "Since large array devices of MOSFETs are huge for driving capabilities, ESD self protections are also required. Then, the large drain contact to poly gate spacing layout rule is usually adopted with large layout areas. In this paper, a new control circuit is implemented for adopting the minimum device layout rule in the LAD. Hence, it results in a very small layout area and ESD self protection capabilities can be established.", "author_names": [ "Hung-Wei Chen", "Shao-Chang Huang", "Mi-Chang Chang", "Jen-Hang Yang", "Tingyou Lin" ], "corpus_id": 45530766, "doc_id": "45530766", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "ESD protection and driving capability switch control circuits for large array NMOSFET driving devices", "venue": "2017 International Conference on Electron Devices and Solid State Circuits (EDSSC)", "year": 2017 }, { "abstract": "This paper presents a detailed study of turn on uniformity under electrostatic discharge events in single finger and multi finger traditional DDSCR devices. Since the structure of the multi finger DDSCR device is not completely symmetrical, the electric field strength of each finger breakdown junction is different, resulting in different impact ionization rates. Therefore, each finger of device cannot be turned on at the same time, and the turned on finger enters the snap back region and pull down the voltage of the device. If the ESD failure voltage Vt2 of the multi finger device is less than the trigger voltage Vt1, then other fingers will not turn on until the device fails, and the ESD current can be only discharged through the partial area. The transmission line pulse (TLP) test results show that the failure currents It2 of the single finger, 2 finger and 4 finger DDSCR devices are 6.22A, 11.83A and 13.33A, respectively, and the 4 finger device cannot be uniformly turned on.", "author_names": [ "Dandan Jia", "Xijun Chen", "Xiangliang Jin" ], "corpus_id": 211056533, "doc_id": "211056533", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Analysis of Turn on Uniformity of Multi finger DDSCR Devices under ESD Stress", "venue": "2019 IEEE 26th International Symposium on Physical and Failure Analysis of Integrated Circuits (IPFA)", "year": 2019 }, { "abstract": "Abstract A novel cascaded complementary dual directional silicon controlled rectifier (CCDSCR) structure has been proposed and implemented in a 0.5 mm 20 V Bipolar/CMOS/DMOS process as an ESD (electrostatic discharge) protection device. The ESD characteristics of the capacitance trigger CCDSCR has been investigated by transmission line pulse (TLP) testing. Compared with the substrate trigger insulated gate bipolar transistor with the enhanced substrate parasitic capacitance, the gate driven trigger insulated gate bipolar transistor with the gate coupling capacitance and the normal dual directional silicon controlled rectifier, the CCDSCR has the highest holding voltage of about 25.4 V and the best current conduction uniformity. In addition, it has the best figure of merit (FOM) with the value of about 0.64 mA/mm 2 The good current conduction uniformity in CCDSCR due to the enhanced substrate parasitic capacitance trigger effect is finally confirmed by Sentaurus simulations.", "author_names": [ "Hailian Liang", "Weidong Nie", "Xiaofeng Gu", "Shurong Dong", "Wai Shing Lau" ], "corpus_id": 206949925, "doc_id": "206949925", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "An investigation on capacitance trigger ESD protection devices for high voltage integrated circuits", "venue": "Microelectron. Reliab.", "year": 2014 }, { "abstract": "A CMOS SCR compact model is developed for circuit simulation of ESD protection circuits. The model is comprised of coupled NPN and PNP transistors. A previously unnoted interaction between these transistors is described, resulting in improved agreement between simulation and measurement. This model addresses fundamental limitations of previous models, allowing for improved simulation accuracy, while limiting the number of parameters. The model parameters are scalable with respect to the layout spacings.", "author_names": [ "Robert Mertens", "Elyse Rosenbaum" ], "corpus_id": 5879972, "doc_id": "5879972", "n_citations": 21, "n_key_citations": 3, "score": 0, "title": "A physics based compact model for SCR devices used in ESD protection circuits", "venue": "2013 IEEE International Reliability Physics Symposium (IRPS)", "year": 2013 }, { "abstract": "Through Silicon Via (TSV) has been utilized in vertically stacking IC dice to implement real system in chip applications. However, threshold voltage and mobility of MOSFETs can be influenced by induced mechanical strain of the TSV, causing degradation or non stability of functional circuits. Therefore, a Keep out Zone (KOZ) is defined, meaning that active devices are forbidden in this area. This paper investigates the impact on ESD protection devices placed inside this KOZ in bulk FinFET process.", "author_names": [ "Shih-Hung Chen", "Steven Thijs", "Dimitri Linten", "Mirko Scholz", "Geert Hellings", "Guido Groeseneken" ], "corpus_id": 40115007, "doc_id": "40115007", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "ESD protection devices placed inside keep out zone (KOZ) of through Silicon Via (TSV) in 3D stacked integrated circuits", "venue": "Electrical Overstress Electrostatic Discharge Symposium Proceedings 2012", "year": 2012 }, { "abstract": "Electrostatic discharge (ESD) is still a challenging reliability issue for integrated circuits (ICs) in advanced CMOS technology. With the development of ICs toward system on chip (SoC) applications, it has been common to integrate multiple separated power domains into a single chip for power management or noise isolation considerations. Besides, the fabricated transistors with thinner gate oxide for high speed operation cause the ICs more sensitive to charged device model (CDM) ESD events, especially under cross domain stresses. The traditional cross domain CDM ESD protection would result in some restrictions on circuit applications or cause some performance degradation. Thus, a new protection design with stacking footer/header metal oxide semiconductor (MOS) structure against cross domain CDM ESD stresses was proposed in this work and verified in 0.18 \\mu \\text{m} CMOS technology. The proposed design got higher ESD robustness under CDM and HBM (human body model) ESD tests. Moreover, the CDM robustness of different stacking MOS protection designs was also investigated in detail.", "author_names": [ "Cheng-Yun Hsueh", "Ming-Dou Ker" ], "corpus_id": 232373913, "doc_id": "232373913", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Stacking MOS Protection Design for Interface Circuits Against Cross Domain CDM ESD Stresses", "venue": "IEEE Transactions on Electron Devices", "year": 2021 }, { "abstract": "In this paper, the total ionizing dose effects on electrostatic discharge (ESD) protection devices are investigated. Irradiation is conducted with 1.5 MeV He+ from a RPEA 4.0 MV Dynamitron accelerator, and the Barth 4002 transmission line pulse (TLP) tester is used for measurements. The ESD devices considered are a P+/NW diode, a Zener diode, gate grounded NMOS (GGNMOS) and lateral silicon controlled rectifiers (LSCR) fabricated in a 0.35 um BCD (Bipolar CMOS DMOS) technology. The pre and post irradiated TLP I V characteristics are analyzed and compared in detail. Significant degradation in ESD protection is observed after exposure of devices to ionizing irradiation.", "author_names": [ "Wei Liang", "Kostas Alexandrou", "Maxim Klebanov", "Chung-Chen Kuo", "Ioannis Kymissis", "Kalpathy B Sundaram", "Juin J Liou" ], "corpus_id": 22963191, "doc_id": "22963191", "n_citations": 4, "n_key_citations": 1, "score": 0, "title": "Characterization of ESD protection devices under total ionizing dose irradiation", "venue": "2017 IEEE 24th International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA)", "year": 2017 }, { "abstract": "Electrostatic discharge (ESD) protection circuits are often designed with detection circuits to trigger clamp devices to bypass ESD currents. In order to fully characterize performance of these protection circuits, a wafer level characterization method is proposed in this work. By separating the detection rail from the supply rail, triggering actions resulted from detection circuits can be clearly captured by the proposed method. Besides, both the component level triggering criteria and system level transient induced latch up (TLU) immunity of ESD protection circuits can be fully characterized by the proposed method. Silicon data based case studies are presented in this work to verify the validity of the proposed method.", "author_names": [ "Yuan Wang", "Guangyi Lu", "Xing Zhang" ], "corpus_id": 43746412, "doc_id": "43746412", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "A wafer level characterization method of ESD protection circuits for both component level and system level applications", "venue": "2016 Asia Pacific International Symposium on Electromagnetic Compatibility (APEMC)", "year": 2016 } ]

[ { "abstract": "Connectivity as the Essential Physics of Disordered Systems Elements of Percolation Theory Characterization of Porous Media Earthquakes, and Fracture and Fault in Patterns in Heterogeneous Rock Single Phase Flow in Reservoir Rock Hydrodynamic Dispersion and Groundwater Flow in Rock Two Phase Flow in Porous Media Transport, Reaction, and Deposition in Evolving Porous Media Fractal Diffusion and Reaction Kinetics Vibrations and Density of States of Disordered Materials Structural, Mechanical, and Rheological Properties of Branched Polymers and Gels Morphological and Transport Properties of Composite Media Hopping Conductivity of Semiconductors Percolation in Biological Systems.", "author_names": [ "Mtabazi G Sahini", "Muhammad Sahimi" ], "corpus_id": 138102708, "doc_id": "138102708", "n_citations": 1100, "n_key_citations": 53, "score": 1, "title": "Applications of percolation theory", "venue": "", "year": 1994 }, { "abstract": "Critical path analysis and percolation theory are known to predict accurately dc and low frequency ac electrical conductivity in strongly heterogeneous solids, and have some applications in statistics. Much of this work is dedicated to review the current state of these theories. Application to heterogeneous porous media has been slower, though the concept of percolation was invented in that context. The definition of the critical path is that path which traverses an infinitely large system, with no breaks, which has the lowest possible value of the largest resistance on the path. This resistance is called the rate limiting, or critical, element, Rc. Mathematical schemes are known for calculating Rc in many cases, but this application is not the focus here. The condition under which critical path analysis and percolation theory are superior to other theories is when heterogeneities are so strong, that transport is largely controlled by a few rate limiting transitions, and the entire potential field governing the transport is influenced by these individual processes. This is the limit of heterogeneous, deterministic transport, characterized by reproducibility (repeatability) This work goes on to show the issues in which progress with this theoretical approach has been slow (in particular, the relationship between a critical rate, or conductance, and the characteristic conductivity) and what progress is being made towards solving them. It describes applications to saturated and unsaturated flows, some of which are new. The state of knowledge regarding application of cluster statistics of percolation theory to find spatial variability and correlations in the hydraulic conductivity is summarized. Relationships between electrical and hydraulic conductivities are explored. Here, as for the relationship between saturated and unsaturated flows, the approach described includes new applications of existing concepts. The specific case of power law distributions of pore sizes, a kind of 'random' fractal soil is discussed (critical path analysis would not be preferred for calculating the hydraulic conductivity of a regular fractal) \" 2001 Elsevier Science Ltd. All rights reserved.", "author_names": [ "Allen G Hunt" ], "corpus_id": 32025812, "doc_id": "32025812", "n_citations": 179, "n_key_citations": 20, "score": 0, "title": "Applications of percolation theory to porous media with distributed local conductances", "venue": "", "year": 2001 }, { "abstract": "There is increasing interest in the use of the percolation paradigm to analyse and predict the progress of disease spreading in spatially structured populations of animals and plants. The wider utility of the approach has been limited, however, by several restrictive assumptions, foremost of which is a strict requirement for simple nearest neighbour transmission, in which the disease history of an individual is influenced only by that of its neighbours. In a recent paper, the percolation paradigm has been generalized to incorporate synergistic interactions in host infectivity and susceptibility, and the impact of these interactions on the invasive dynamics of an epidemic has been demonstrated. In the current paper, we elicit evidence that such synergistic interactions may underlie transmission dynamics in real world systems by first formulating a model for the spread of a ubiquitous parasitic and saprotrophic fungus through replicated populations of nutrient sites and subsequently fitting and testing the model using data from experimental microcosms. Using Bayesian computational methods for model fitting, we demonstrate that synergistic interactions are necessary to explain the dynamics observed in the replicate experiments. The broader implications of this work in identifying disease control strategies that deflect epidemics from invasive to non invasive regimes are discussed.", "author_names": [ "Jonathan J Ludlam", "Gavin J Gibson", "Wilfred Otten", "Christopher A Gilligan" ], "corpus_id": 19217817, "doc_id": "19217817", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Applications of percolation theory to fungal spread with synergy", "venue": "Journal of The Royal Society Interface", "year": 2011 }, { "abstract": "", "author_names": [ "Gary A Talbot" ], "corpus_id": 131226494, "doc_id": "131226494", "n_citations": 255, "n_key_citations": 16, "score": 0, "title": "Applications of Percolation Theory", "venue": "", "year": 1995 }, { "abstract": "The review is a brief description of the state of problems in percolation theory and their numerous applications, which are analyzed on base of interesting papers published in the last 15 20 years. At the submitted papers are studied both the cluster system of the physical body and its impact on the object in general, and adequate mathematical tools for description of critical phenomena too. Of special interest are the data, first, the point of phase transition of certain of percolation system is not really a point, but it is a critical interval, and second, in vicinity of percolation threshold observed many different infinite clusters instead of one infinite cluster that appears in traditional consideration.", "author_names": [ "Alexander Herega" ], "corpus_id": 40576218, "doc_id": "40576218", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Some Applications of the Percolation Theory. Brief Review of the Century Beginning", "venue": "", "year": 2015 }, { "abstract": "During the past two decades, percolation has long served as a basic paradigm for network resilience, community formation and so on in complex systems. While the percolation transition is known as one of the most robust continuous transitions, the percolation transitions occurring in complex systems are often of different types such as discontinuous, hybrid, and infinite order phase transitions. Thus, percolation has received considerable attention in network science community. Here we present a very brief review of percolation theory recently developed, which includes those types of phase transitions, critical phenomena, and finite size scaling theory. Moreover, we discuss potential applications of theoretical results and several open questions including universal behaviors.", "author_names": [ "Deokjae Lee", "Byungnam Kahng", "Y S Cho", "Kwang-Il Goh", "D -S Lee" ], "corpus_id": 119526098, "doc_id": "119526098", "n_citations": 22, "n_key_citations": 1, "score": 0, "title": "Recent Advances of Percolation Theory in Complex Networks", "venue": "", "year": 2018 }, { "abstract": "In the experimental work presented here, fire spread was studied through various laboratory and full scale models containing different types of combustible and noncombustible materials. We have exa.", "author_names": [ "J Nahmias", "Herve Tephany", "Jose A M S Duarte", "Sophie Letaconnoux" ], "corpus_id": 84362847, "doc_id": "84362847", "n_citations": 21, "n_key_citations": 1, "score": 0, "title": "Fire spreading experiments on heterogeneous fuel beds. Applications of percolation theory", "venue": "", "year": 2000 }, { "abstract": "The application of percolation theory concepts to modelling of a single particle char gasification has been summarized. Emphasis has been placed on the interpretation and evaluation of transport and fragmentation properties of the changing pore structure during gasification. The qualitative behavior of the model in both the kinetically and the diffusionally controlled regimes clearly reflect the strong influence of structural properties on gasification. Furthermore, the good agreement between these model predictions and reported experimental observations are encouraging for further use of percolation theory in modelling changing coal structures. 25 references, 7 figures, 2 tables.", "author_names": [ "Sebastian C Reyes", "Klavs F Jensen" ], "corpus_id": 135925056, "doc_id": "135925056", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Applications of percolation theory to the analysis of coal gasification", "venue": "", "year": 1985 }, { "abstract": "Percolation is the simplest fundamental model in statistical mechanics that exhibits phase transitions signaled by the emergence of a giant connected component. Despite its very simple rules, percolation theory has successfully been applied to describe a large variety of natural, technological and social systems. Percolation models serve as important universality classes in critical phenomena characterized by a set of critical exponents which correspond to a rich fractal and scaling structure of their geometric features. In this review we will first outline the basic features of the ordinary model and take a glimpse at a number of selective variations and modifications of the original model. Directed percolation process will be also discussed as a prototype of systems displaying a nonequilibrium phase transition. After a short review on SLE, we will provide an overview on existence of the scaling limit and conformal invariance of the critical percolation. We will also establish a connection with the magnetic models. Recent applications of the percolation theory in natural and artificial landscapes are also reviewed.", "author_names": [ "Abbas Ali Saberi" ], "corpus_id": 119209128, "doc_id": "119209128", "n_citations": 218, "n_key_citations": 2, "score": 0, "title": "Recent advances in percolation theory and its applications", "venue": "", "year": 2015 }, { "abstract": "", "author_names": [ "Tamaz L Chelidze" ], "corpus_id": 129276610, "doc_id": "129276610", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Applications of percolation theory: By M. Sahimi. Taylor Francis, London, 1994, hardcover, 258 pp. PS40.00. (ISBN 0 7484 0075 3)", "venue": "", "year": 1995 } ]

[ { "abstract": "Heterogeneous interfaces that are ubiquitous in optoelectronic devices play a key role in the device performance and have led to the prosperity of today's microelectronics. Interface engineering provides an effective and promising approach to enhancing the device performance of organic field effect transistors (OFETs) and even developing new functions. In fact, researchers from different disciplines have devoted considerable attention to this concept, which has started to evolve from simple improvement of the device performance to sophisticated construction of novel functionalities, indicating great potential for further applications in broad areas ranging from integrated circuits and energy conversion to catalysis and chemical/biological sensors. In this review article, we provide a timely and comprehensive overview of current efficient approaches developed for building various delicate functional interfaces in OFETs, including interfaces within the semiconductor layers, semiconductor/electrode interfaces, semiconductor/dielectric interfaces, and semiconductor/environment interfaces. We also highlight the major contributions and new concepts of integrating molecular functionalities into electrical circuits, which have been neglected in most previous reviews. This review will provide a fundamental understanding of the interplay between the molecular structure, assembly, and emergent functions at the molecular level and consequently offer novel insights into designing a new generation of multifunctional integrated circuits and sensors toward practical applications.", "author_names": [ "Hongliang Chen", "Weining Zhang", "Mingliang Li", "Gen He", "Xuefeng Guo" ], "corpus_id": 211230652, "doc_id": "211230652", "n_citations": 40, "n_key_citations": 0, "score": 1, "title": "Interface Engineering in Organic Field Effect Transistors: Principles, Applications, and Perspectives.", "venue": "Chemical reviews", "year": 2020 }, { "abstract": "", "author_names": [ "Minjun Kim", "Seung Un Ryu", "Sang Ah Park", "Kyoungwon Choi", "Taehyun Kim", "Dasol Chung", "Taiho Park" ], "corpus_id": 202073686, "doc_id": "202073686", "n_citations": 73, "n_key_citations": 1, "score": 0, "title": "Donor Acceptor Conjugated Polymer for High Performance Organic Field Effect Transistors: A Progress Report", "venue": "Advanced Functional Materials", "year": 2019 }, { "abstract": "", "author_names": [ "Matthew Waldrip", "Oana D Jurchescu", "David J Gundlach", "Emily G Bittle" ], "corpus_id": 203938200, "doc_id": "203938200", "n_citations": 61, "n_key_citations": 0, "score": 0, "title": "Contact Resistance in Organic Field Effect Transistors: Conquering the Barrier", "venue": "Advanced Functional Materials", "year": 2019 }, { "abstract": "Solution printed organic single crystalline films hold great potential for achieving low cost manufacturing of large area and flexible electronics. For practical applications, organic field effect transistor arrays must exhibit high performance and small device to device variation. However, scalable fabrication of highly aligned organic crystalline arrays is rather difficult due to the lack of control over the crystallographic orientation, crystal uniformity, and thickness. Here, a facile solution printing method to fabricate centimeter sized highly aligned organic crystalline arrays with a thickness of a few molecular layers is reported. In this study, the solution shearing technique is used to produce large area, organic highly crystalline thin films. Water soluble ink is printed on the hydrophobic surface of organic crystalline films, to selectively protect it, followed by etching. It is shown that the addition of a surfactant dramatically changes the fluid drying dynamics and increases the contact line friction of the aqueous solution to the underlying nonwetting organic crystalline film. As a result, centimeter scale highly aligned organic crystalline arrays are successfully prepared on different substrates. The devices based on organic crystalline arrays show good performance and uniformity. This study demonstrates that solution printing is close to industrial application and also expands its applicability to various printed flexible electronics.", "author_names": [ "Shuming Duan", "Tian-Yu Wang", "Bowen Geng", "Xiong Gao", "Chenguang Li", "Jincheng Zhang", "Yuewen Xi", "Xiaotao Zhang", "Xiaochen Ren", "Wenping Hu" ], "corpus_id": 211101505, "doc_id": "211101505", "n_citations": 29, "n_key_citations": 0, "score": 0, "title": "Solution Processed Centimeter Scale Highly Aligned Organic Crystalline Arrays for High Performance Organic Field Effect Transistors.", "venue": "Advanced materials", "year": 2020 }, { "abstract": "The strong and controllable chemical sensitivity of organic semiconductors (OSCs) and the amplification capability of transistors in circuits make use of OSC based field effect transistors compelling for chemical sensors. Analytes detected and assayed range from few atom gas phase molecules that may have adverse health and security implications to biomacromolecules (proteins, nucleic acids) that may be markers for physiological processes and medical conditions. This review highlights recent progress in organic field effect transistor (OFET) chemical sensors, emphasizing advances from the past 5 years and including aspects of OSC morphology and the role of adjacent dielectrics. Design elements of the OSCs and various formats for the devices are illustrated and evaluated. Challenges associated with the present state of the art and future opportunities are also discussed.", "author_names": [ "Hui Li", "Wei Shi", "Jian Song", "Hyun-June Jang", "Jennifer Dailey", "Junsheng Yu", "Howard E Katz" ], "corpus_id": 53208875, "doc_id": "53208875", "n_citations": 140, "n_key_citations": 0, "score": 0, "title": "Chemical and Biomolecule Sensing with Organic Field Effect Transistors.", "venue": "Chemical reviews", "year": 2019 }, { "abstract": "Over the past 25 years, organic field effect transistors (OFETs) have witnessed impressive improvements in materials performance by 3 4 orders of magnitude, and many of the key materials discoveries have been published in Advanced Materials. This includes some of the most recent demonstrations of organic field effect transistors with performance that clearly exceeds that of benchmark amorphous silicon based devices. In this article, state of the art in OFETs are reviewed in light of requirements for demanding future applications, in particular active matrix addressing for flexible organic light emitting diode (OLED) displays. An overview is provided over both small molecule and conjugated polymer materials for which field effect mobilities exceeding 1 cm2 V 1 s 1 have been reported. Current understanding is also reviewed of their charge transport physics that allows reaching such unexpectedly high mobilities in these weakly van der Waals bonded and structurally comparatively disordered materials with a view towards understanding the potential for further improvement in performance in the future.", "author_names": [ "Henning Sirringhaus" ], "corpus_id": 11738028, "doc_id": "11738028", "n_citations": 1558, "n_key_citations": 11, "score": 0, "title": "25th Anniversary Article: Organic Field Effect Transistors: The Path Beyond Amorphous Silicon", "venue": "Advanced materials", "year": 2014 }, { "abstract": "Printable organic field effect transistors (OFETs) have been investigated for more than 20 years, aiming at various emerging applications including flexible/wearable electronics, displays and sensors. Since many comprehensive review articles for this field have been published, here we will focus on the recent progress of this field and address the following issues critical to the future applications of OFETs. First, downscaling technologies for the printing of OFETs with fine resolution will be reviewed. The approaches for short channels and small overlapping as well as patterning of organic semiconductors are summarized. Second, various approaches for realizing low voltage OFETs will be presented, which are critical to the power consumption of organic devices. Specifically, the operational voltages of OFETs have been successfully decreased to several volts by increasing the gate dielectric capacitance and reducing the sub gap density of states at the channel. This review will provide guidelines for material design and fabrication processes of OFETs with high performance and advanced applications.", "author_names": [ "Wei Tang", "Yukun Huang", "Lei Han", "Ruili Liu", "Yuezeng Su", "Xiaojun Guo", "Feng Yan" ], "corpus_id": 139991358, "doc_id": "139991358", "n_citations": 51, "n_key_citations": 0, "score": 0, "title": "Recent progress in printable organic field effect transistors", "venue": "", "year": 2019 }, { "abstract": "Abstract Crystal orientation is one of the key parameters for organic field effect transistors (OFETs) Here, DPP based material with polymer as additive was carried out to fabricate self assembly organic crystals. By optimizing the blend ratios and concentrations of the solution, well aligned, high quality crystals were successfully achieved. Optical microscope, scanning electron microscope (SEM) and X ray diffraction (XRD) were used to characterize the crystals. OFET devices were made using the crystals grown under the optimal condition. Comparing with the devices made by thin films, mobility fabricated by crystals is two order of magnitude higher. We anticipate our finding will promote the development of the field.", "author_names": [ "Sheng Bi", "Yu Li", "Zhengran He", "Zhongliang Ouyang", "Qinglei Guo", "Chengming Jiang" ], "corpus_id": 105755864, "doc_id": "105755864", "n_citations": 46, "n_key_citations": 0, "score": 0, "title": "Self assembly diketopyrrolopyrrole based materials and polymer blend with enhanced crystal alignment and property for organic field effect transistors", "venue": "Organic Electronics", "year": 2019 }, { "abstract": "Benefiting from the advantages of organic field effect transistors (OFETs) including synthetic versatility of organic molecular design and environmental sensitivity, gas sensors based on OFETs have drawn much attention in recent years. Potential applications focus on the detection of specific gas species such as explosive, toxic gases, or volatile organic compounds (VOCs) that play vital roles in environmental monitoring, industrial manufacturing, smart health care, food security, and national defense. To achieve high sensitivity, selectivity, and ambient stability with rapid response and recovery speed, the regulation and adjustment of the nano/microstructure of the organic semiconductor (OSC) layer has proven to be an effective strategy. Here, the progress of OFET gas sensors with nano/microstructure is selectively presented. Devices based on OSC films one dimensional (1D) single crystal nanowires, nanorods, and nanofibers are introduced. Then, devices based on two dimensional (2D) and ultrathin OSC films, fabricated by methods such as thermal evaporation, dip coating, spin coating, and solution shearing methods are presented, followed by an introduction of porous OFET sensors. Additionally, the applications of nanostructured receptors in OFET sensors are given. Finally, an outlook in view of the current research state is presented and eight further challenges for gas sensors based on OFETs are suggested.", "author_names": [ "Shi-qi Zhang", "Yiwei Zhao", "Xiaowen Du", "Yingli Chu", "Shen Zhang", "Jia Huang" ], "corpus_id": 73451866, "doc_id": "73451866", "n_citations": 41, "n_key_citations": 0, "score": 0, "title": "Gas Sensors Based on Nano/Microstructured Organic Field Effect Transistors.", "venue": "Small", "year": 2019 }, { "abstract": "The emergence of flexible organic electronics that span the fields of physics and biomimetics creates the possibility for increasingly simple and intelligent products for use in everyday life. Organic field effect transistors (OFETs) with their inherent flexibility, light weight, and biocompatibility, have shown great promise in the field of biomimicry. By applying such biomimetic OFETs for the internet of things (IoT) makes it possible to imagine novel products and use cases for the future. Recent advances in flexible OFETs and their applications in biomimetic systems are reviewed. Strategies to achieve flexible OFETs are individually discussed and recent progress in biomimetic sensory systems and nervous systems is reviewed in detail. OFETs are revealed to be one of the best systems for mimicking sensory and nervous systems. Additionally, a brief discussion of information storage based on OFETs is presented. Finally, a personal view of the utilization of biomimetic OFETs in the IoT and future challenges in this research area are provided.", "author_names": [ "Wei Shi", "Yunlong Guo", "Yunqi Liu" ], "corpus_id": 195757507, "doc_id": "195757507", "n_citations": 48, "n_key_citations": 1, "score": 0, "title": "When Flexible Organic Field Effect Transistors Meet Biomimetics: A Prospective View of the Internet of Things.", "venue": "Advanced materials", "year": 2019 } ]

[ { "abstract": "Avalanche photodiodes, which operate above the breakdown voltage in Geiger mode connected with avalanche quenching circuits, can be used to detect single photons and are therefore called singlephoton avalanche diodes SPAD's. Circuit configurations suitable for this operation mode are critically analyzed and their relative merits in photon counting and timing applications are assessed. Simple passive quenching circuits (PQC's) which are useful for SPAD device testing and selection, have fairly limited application. Suitably designed active quenching circuits (AQC's) make it possible to exploit the best performance of SPAD's. Thick silicon SPAD's that operate at high voltages (250 450 V) have photon detection efficiency higher than 50% from 540 to 850 nm wavelength and still ~3% at 1064 nm. Thin silicon SPAD's that operate at low voltages (10 50 V) have 45% efficiency at 500 nm, declining to 10% at 830 nm and to as little as 0.1% at 1064 nm. The time resolution achieved in photon timing is 20 ps FWHM with thin SPAD's; it ranges from 350 to 150 ps FWHM with thick SPAD's. The achieved minimum counting dead time and maximum counting rate are 40 ns and 10 Mcps with thick silicon SPAD's, 10 ns and 40 Mcps with thin SPAD's. Germanium and III V compound semiconductor SPAD's extend the range of photon counting techniques in the near infrared region to at least 1600 nm wavelength.", "author_names": [ "Sergio Cova", "Massimo Ghioni", "Andrea Leonardo Lacaita", "Carlo Samori", "Franco Zappa" ], "corpus_id": 12315693, "doc_id": "12315693", "n_citations": 1015, "n_key_citations": 97, "score": 0, "title": "Avalanche photodiodes and quenching circuits for single photon detection.", "venue": "Applied optics", "year": 1996 }, { "abstract": "Integrated microwave photonics (IMWP) is concerned with applying integrated photonics technology to microwave photonic systems. It is one of the most active and exciting areas of current research and development in microwave photonics (MWP) building upon the impressive foundations of integrated photonics in various systems involving material platforms such as indium phosphide (InP) and silicon nitride (Si3N4) The aim of this article is to explain to the wider microwave engineering community the significance of the new field of IMWP and to describe how it may potentially be applied to improve the performance and capabilities of microwave and millimeter wave (mmWave) systems. Just as the microwave monolithic integrated circuit (MMIC) has revolutionized active microwave circuits, IMWP is poised to open up new applications for microwave engineering that take advantage of the unique functionalities offered by photonics, especially with regard to its large bandwidth.", "author_names": [ "Stavros Iezekiel", "Maurizio Burla", "Jonathan Klamkin", "David A I Marpaung", "Jose Capmany" ], "corpus_id": 38524397, "doc_id": "38524397", "n_citations": 61, "n_key_citations": 5, "score": 0, "title": "RF Engineering Meets Optoelectronics: Progress in Integrated Microwave Photonics", "venue": "IEEE Microwave Magazine", "year": 2015 }, { "abstract": "We report on noise characterization of a midwave infrared (MWIR) InAs/GaSb superlattice (SL) single detector. The SL structure was made of eight InAs monolayers (MLs) and eight GaSb MLs, with a total thickness of 2 mm (440 SL periods) This structure exhibits a cut off wavelength of 4.8 mm at 77 K. Extracted from current voltage characteristics, zero bias resistance area product R0 A above 5x105 O cm2 at 80 K was measured. Noise measurements were also performed under dark conditions. The measurements reveal the absence of 1/f noise above 30 Hz. Moreover, the detector under test remains Schottky noise limited up to a bias voltage of 200 mV typically, which confirms the quality of the MWIR SL pin photodiode.", "author_names": [ "Katarzyna Jaworowicz", "Isabelle Ribet-Mohamed", "C Cervera", "J B Rodriguez", "Philippe Christol" ], "corpus_id": 12183033, "doc_id": "12183033", "n_citations": 18, "n_key_citations": 1, "score": 0, "title": "Noise Characterization of Midwave Infrared InAs/GaSb Superlattice pin Photodiode", "venue": "IEEE Photonics Technology Letters", "year": 2011 }, { "abstract": "A new Optical High Frequency test structure and dedicated test bench have been developed to characterize a Germanium on Silicon photodiode intended to be used as an integrated noise source, a first step to high frequency transistor noise figure on wafer extraction. Continuous wave signals have been measured from these 1550 nm photodiodes, with RF power higher than 20 dBm at 109 GHz.", "author_names": [ "S Oeuvrard", "Jean-Francois Lampin", "Guillaume Ducournau", "Leopold Virot", "Jean-Marc Fedeli", "J M Hartmann", "Francois Danneville", "Yvan Morandini", "Daniel Gloria" ], "corpus_id": 8523454, "doc_id": "8523454", "n_citations": 5, "n_key_citations": 2, "score": 0, "title": "Optical high frequency test structure and test bench definition for on wafer silicon integrated noise source characterization up to 110 GHz based on Germanium on Silicon photodiode", "venue": "2013 IEEE International Conference on Microelectronic Test Structures (ICMTS)", "year": 2013 }, { "abstract": "We present a full characterization of the radiometric performances of a type II InAs/GaSb superlattice pin photodiode operating in the mid wavelength infrared domain. We first focused our attention on quantum efficiency, responsivity and angular response measurements: quantum efficiency reaches 23% at l 2.1 um for 1 um thick structure. Noise under illumination measurements are also reported: noise is limited by the Schottky contribution for reverse bias voltage smaller than 1.2 V. The specific detectivity, estimated for 2p field of view and 333 K background temperature, was determined equal to 2.29 x 10^10 Jones for 0,8 V bias voltage and 77 K operating temperature.", "author_names": [ "E Giard", "Rachid Taalat", "Marie Delmas", "Julia Bella Rodriguez", "Philippe Christol", "Isabelle Ribet-Mohamed" ], "corpus_id": 3349327, "doc_id": "3349327", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Radiometric and noise characteristics of InAs rich T2SL MWIR pin photodiodes", "venue": "", "year": 2014 }, { "abstract": "Solid state light matter interfaces based on crystals doped with rare earth ions have shown great progress in recent years, heading towards quantum technology applications. In this thesis we present three experiments testing the suitability of an atomic frequency comb light matter interface, implemented in an Nd:YSO crystal, for the storage of quantum information. A dedicated source of entangled photons has been developed, and the storage and retrieval of quantum correlations and entanglement been studied. We show the successful transfer of photonic entanglement to the crystal, and the generation of a matter matter entangled state between two crystals. These are two of the main steps in a quantum repeater protocol. We also demonstrate faithful storage and retrieval of quantum information encoded in the polarization of heralded single photons. These experiments prove the strong potential of solid state light matter interfaces based on atomic frequency combs for quantum communication.", "author_names": [ "Christoph Clausen" ], "corpus_id": 115928999, "doc_id": "115928999", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Solid state light matter interfaces on the quantum test bench", "venue": "", "year": 2013 }, { "abstract": "A photonic delay line is used as a frequency discriminator for measurement of the phase noise hence the short term frequency stability of microwave oscillators. The scheme is suitable for electronic and photonic oscillators, including the optoelectronic oscillator, mode lock lasers, and other types of rf and microwave pulsed optical sources. The approach is inherently suitable for a wide range of frequency without reconfiguration, which is important for the measurement of tunable oscillators. It is also insensitive to a moderate frequency drift without the need for phase locking.", "author_names": [ "Enrico Rubiola", "Ertan Salik", "Shouhua Huang", "Nan Yu", "Lute Maleki" ], "corpus_id": 54822488, "doc_id": "54822488", "n_citations": 89, "n_key_citations": 3, "score": 0, "title": "Photonic delay technique for phase noise measurement of microwave oscillators", "venue": "", "year": 2005 }, { "abstract": "The development of a high throughput, accurate, and cost efficient inline optical test system is a key challenge to mass manufacturing of silicon photonics. For our Silicon Photonic technologies, we developed a fully automated wafer level optical test system for both, active and passive optical testing. The measured insertion loss of fiber grating couplers is repeatable within 1.1dB (3s) A unique forward and reverse alternative test method is designed to extract photodetector responsivity.", "author_names": [ "Shuren Hu", "Andy Stricker", "Kate McLean", "Calvin Ma", "Subharup Gupta Roy", "Dean Percy", "John Cartier", "David Clark", "Raymond van Roijen", "Bart Green", "Kevin Dezfulian", "Louis Medina", "John Ferrario", "Dave Riggs", "K J Giewont" ], "corpus_id": 46958685, "doc_id": "46958685", "n_citations": 2, "n_key_citations": 1, "score": 1, "title": "Fully automated in line optical test system: Advanced materials photonics", "venue": "2018 29th Annual SEMI Advanced Semiconductor Manufacturing Conference (ASMC)", "year": 2018 }, { "abstract": "We report on fabricating ErxY2 xSiO5 nanocrystals using ErCl36H2O and YCl36H2O solutions and Si nanowires grown by VSL method. Use of crystalline host allows incorporation of up to 25 at. Er without clustering and loss of optical activity, and use of Y enables continuous mixing of Er and Y for controlling cooperative upconversion. We obtain a cooperative upconversion coefficients of (2.2+ 1.1)x10 cm/s and (5.4+ 2.7)x10 cm/s at an Er concentration of 1.2x10 cm and 2.0x10 cm, respectively. These values are up to 10 times lower at 10 times higher Er concentration than those reported for Er doped silica, and shows that up to 69 dB/cm gain could be achieved for ultra compact optical amplification. Also, we report on the deposition of ErxY2 xSiO5 thin film on Si substrate using ion beam sputter deposition. Rapid thermal annealing at 1100 degC is enough to form crystal phase the film and activate most of Er ions.", "author_names": [ "Fuad E Doany", "Daniel M Kuchta", "Laurent Schares", "Russell A Budd", "Frank R Libsch" ], "corpus_id": 201648690, "doc_id": "201648690", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Photonics Packaging Integration and Interconnects VIII", "venue": "", "year": 2008 }, { "abstract": "High density germanium photodiode arrays are integrated on top of a dummy CMOS 200 mm Silicon wafer. Using a conventional available semiconductor fabrication line, the target specifications are reached with a yield exceeding 99% for several thousands of tested photodiodes with respect to bandwidth, responsivity, and dark current. A very low dark current density in the range of 7 mA/cm2 is obtained. A median bandwidth above 9 GHz is reached with a large 30 mm diameter photodiode.", "author_names": [ "Christophe Kopp", "Alexandre Ferron", "Jean-Michel Hartmann", "Maryse Fournier", "Emmanuel Augendre", "Philippe Grosse", "Jean-Marc Fedeli", "Henk Derks" ], "corpus_id": 43140540, "doc_id": "43140540", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Wafer Level High Speed Germanium Photodiode Array Integration", "venue": "IEEE Journal of Selected Topics in Quantum Electronics", "year": 2011 } ]

[ { "abstract": "The intensity noise of a quantum dot, coherent comb source laser is characterized using time and frequency domain measurements. The time domain measurements yield the average relative intensity noise (RIN) over the measurement bandwidth, and by calculation, the correlation time and power spectral density (frequency resolved RIN) The frequency domain measurements yield the RIN spectrum and, by calculation, the integrated RIN. The short duration (50 \\mu$s) time domain results exhibit a line to line variability in the properties of the intensity noise that is not revealed by the frequency domain measurements. It is shown that the RIN of a comb line can be reduced by over 13 dB using a saturated semiconductor optical amplifier (SOA) The performance of a low complexity, low latency 40 Gb/s intensity modulation, direct detection system using a comb line as a CW source, without and with SOA based noise suppression, is assessed in terms of the bit error ratio.", "author_names": [ "John C Cartledge", "M O'sullivan" ], "corpus_id": 198461634, "doc_id": "198461634", "n_citations": 6, "n_key_citations": 0, "score": 1, "title": "Time and Frequency Domain Characterization of the Relative Intensity Noise of a Quantum Dot Frequency Comb Source Laser", "venue": "IEEE Journal of Selected Topics in Quantum Electronics", "year": 2019 }, { "abstract": "We report a reduction of the relative intensity noise (RIN) in a dual state emitting quantum dot laser subject to the state selective optical feedback on the ground state and excited state. Numerically, we map the evolution of the RIN for variations of the optical feedback phases for both states. We report important differences in the impact of the feedback when applied to the ground or excited state, and observe regimes for which a significant reduction in RIN is achieved. Experimentally, we confirm these results and achieve a 16 dB reduction of the RIN via a careful and independent tuning of the optical feedback phase for each state.", "author_names": [ "Robert Pawlus", "Stefan Breuer", "Martin Virte" ], "corpus_id": 46756635, "doc_id": "46756635", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Relative intensity noise reduction in a dual state quantum dot laser by optical feedback.", "venue": "Optics letters", "year": 2017 }, { "abstract": "We investigate the spectrally resolved relative intensity noise (RIN) of a dual state emitting quantum dot (QD) laser in dependence on the laser biasing conditions. We study the RIN under free running conditions as well as under external optical feedback (OFB) We i!nd an improvement in RIN of the free running laser when ground state (GS) and excited state (ES) emit simultaneously as compared to a single state emission. Furthermore, we i!nd an improvement in RIN under external OFB.", "author_names": [ "Robert Pawlus", "Mariangela Gioannini", "Martin Virte", "Wolfgang Elsasser", "Stefan Breuer" ], "corpus_id": 125017873, "doc_id": "125017873", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Investigations on the relative intensity noise of a two state quantum dot laser", "venue": "SPIE Photonics Europe", "year": 2016 }, { "abstract": "This paper investigates the intensity noise and pulse oscillation characteristics of an InAs/GaAs quantum dot laser epitaxially grown on germanium. We show that the relative intensity noise of the free running laser generally decreases with increasing pump current, and the minimum value reaches down to about $126 dB/Hz. The intensity noise is hardly affected by the optical feedback, unless there is a resonance or pulse oscillation in the noise spectrum. The laser pumped at a high current is more sensitive to the optical feedback. Interestingly, it is found that the free running Ge based quantum dot laser generates self sustained pulse oscillations with one period or two periods upon the pump current, without incorporating saturable absorbers. This behavior is valuable for both self generation of photonic microwaves and for understanding nonlinear dynamics of semiconductor lasers.", "author_names": [ "Yueguang Zhou", "Jianan Duan", "Heming Huang", "Xuyi Zhao", "Chunfang Cao", "Qian Gong", "Frederic Grillot", "Cheng Wang" ], "corpus_id": 174804220, "doc_id": "174804220", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Intensity Noise and Pulse Oscillations of an InAs/GaAs Quantum Dot Laser on Germanium", "venue": "IEEE Journal of Selected Topics in Quantum Electronics", "year": 2019 }, { "abstract": "This paper numerically investigates the relative intensity noise of quantum dot lasers through a rate equation model taking into account both the spontaneous emission and carrier contributions. In particular, results show that the carrier noise originating from the ground and excited states significantly enhances the relative intensity noise of the laser, while that from the carrier reservoir does not. Simulations also point out that a large energy interval between the quantum confined levels is more suitable for low intensity noise operation due to the reduced contribution from the carrier noise in the excited state. Finally, the carrier noise is found to have little impact on the frequency noise, thus being negligible for the investigation of the spectral linewidth. Overall, this paper is useful for designing low noise quantum dot oscillators for high speed communications, optical frequency combs, and radar applications.", "author_names": [ "Jianan Duan", "Xing-guang Wang", "Yueguang Zhou", "Cheng Wang", "Frederic Grillot" ], "corpus_id": 53784018, "doc_id": "53784018", "n_citations": 13, "n_key_citations": 1, "score": 0, "title": "Carrier Noise Enhanced Relative Intensity Noise of Quantum Dot Lasers", "venue": "IEEE Journal of Quantum Electronics", "year": 2018 }, { "abstract": "In this paper, for the first time, we present a semiclassical noise model for InAs/GaAs quantum dot (QD) laser considering two photon modes, i.e. ground and first excited states lasing. This model is based on the five level rate equations. By using this model, the effect of temperature variations on relative intensity noise (RIN) of QD laser is investigated. We find that the RIN significantly degrades when excited state (ES) lasing emerges at high temperature. Furthermore, we investigate the influence of the quantum dot numbers on the RIN properties.", "author_names": [ "Ashkan Horri", "Seyedeh Zahra Mirmoeini", "Rahim Faez" ], "corpus_id": 117178521, "doc_id": "117178521", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Relative intensity noise study in two mode quantum dot laser", "venue": "", "year": 2011 }, { "abstract": "We report the relative intensity noise (RIN) characteristics of an InAs quantum dot (Qdot) laser epitaxially grown on the Ge substrate. It is found that the minimum RIN of the Ge based Qdot laser is around 120 dB/Hz, which is 15 dB higher than that of a native GaAs based Qdot laser with the same layer structure. The higher RIN in the Ge based laser can be attributed to the high density epitaxial defects of threading dislocations and antiphase domain boundaries.", "author_names": [ "Yueguang Zhou", "Cheng Zhou", "Chunfang Cao", "Jiangbing Du", "Qian Gong", "Cheng Wang" ], "corpus_id": 125870410, "doc_id": "125870410", "n_citations": 19, "n_key_citations": 0, "score": 0, "title": "Relative intensity noise of InAs quantum dot lasers epitaxially grown on Ge", "venue": "", "year": 2017 }, { "abstract": "We describe modulation responses and relative intensity noise (RIN) spectra of an InAs/GaAs quantum dot laser operating near 1300 nm. A very large nonlinear gain compression coefficient yields a highly damped modulation response with a maximum 3 dB bandwidth of ~6.5 GHz and flat RIN spectra which reach as low a level as 158/ 160 dB/Hz at frequencies up to 10 GHz.", "author_names": [ "Amir Capua", "L Rozenfeld", "Vissarion Mikhelashvili", "Gadi Eisenstein", "Matthias Kuntz", "Matthias Laemmlin", "Dieter H Bimberg" ], "corpus_id": 29742238, "doc_id": "29742238", "n_citations": 54, "n_key_citations": 3, "score": 0, "title": "Direct correlation between a highly damped modulation response and ultra low relative intensity noise in an InAs/GaAs quantum dot laser.", "venue": "Optics express", "year": 2007 }, { "abstract": "We report, for the first time, a low noise high channel count 20 GHz passively mode locked quantum dot laser grown on CMOS compatible on axis (001) silicon substrate. The laser demonstrates a wide mode locking regime in the O band. A record low timing jitter value of 82.7 fs (4 80 MHz) and a narrow RF 3 dB linewidth of 1.8 kHz are reported. A total of 58 wavelength channels within 3 dB optical bandwidth (80 lines within 10 dB) is also shown. The integrated average relative intensity noise values of the whole spectrum and a single channel are 152 dB/Hz and 133 dB/Hz in the frequency range from 10 MHz to 10 GHz, respectively.", "author_names": [ "Songtao Liu", "Daehwan Jung", "Justin C Norman", "M J Kennedy", "Arthur C Gossard", "John E Bowers" ], "corpus_id": 115979648, "doc_id": "115979648", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Low Noise High Channel Count 20 GHz Passively Mode Locked Quantum Dot Laser Grown on Si", "venue": "2019 Optical Fiber Communications Conference and Exhibition (OFC)", "year": 2019 }, { "abstract": "We report low noise, high performance single transverse mode 1.3 mm InAs/GaAs quantum dot lasers monolithically grown on silicon (Si) using molecular beam epitaxy. The fabricated narrow ridge waveguide Fabry Perot (FP) lasers have achieved a room temperature continuous wave (CW) threshold current of 12.5 mA and high CW temperature tolerance up to 90degC. An ultra low relative intensity noise of less than 150 dB/Hz is measured in the 4 16 GHz range. Using this low noise Si based laser, we then demonstrate 25.6 Gb/s data transmission over 13.5 km SMF 28. These low cost FP laser devices are promising candidates to provide cost effective solutions for use in uncooled Si photonics transmitters in inter/hyper data centers and metropolitan data links.", "author_names": [ "Mengya Liao", "Siming Chen", "Zhixin Liu", "Lalitha Ponnampalam", "Zichuan Zhou", "Jiang Wu", "Mingchu Tang", "Samuel Shutts", "Zizhuo Liu", "Peter M Smowton", "Siyuan Yu", "Alwyn J Seeds", "Huiyun Liu" ], "corpus_id": 52952187, "doc_id": "52952187", "n_citations": 25, "n_key_citations": 0, "score": 0, "title": "Low noise 1.3 mm InAs/GaAs quantum dot laser monolithically grown on silicon", "venue": "", "year": 2018 } ]

[ { "abstract": "We have studied experimentally and theoretically the optical orientation and spin dependent Shockley Read Hall recombination in a semiconductor in a magnetic field at an arbitrary angle a between the field and circularly polarized exciting beam. The experiments are performed at room temperature in GaAs1 xNx alloys where deep paramagnetic centers are responsible for the spin dependent recombination. The observed magnetic field dependences of the circular polarization r(B) and intensity J(B) of photoluminescence can be approximately presented as a superposition of two Lorentzian contours, normal and inverted, with their half widths differing by an order of magnitude. The normal, narrow, Lorentzian contour is associated with depolarization of the transverse (to the field) component of spin polarization of the localized electrons, whereas the inverted, broad, Lorentzian is due to suppression of the hyperfine interaction of the localized electron with the own nucleus of the defect. The ratio between the height of one Lorentzian and depth of the other is governed by the field tilt angle a. In contrast to the hyperfine interaction of a shallow donor bound electron with a large number of nuclei of the crystal lattice, in the optical orientation of the electron nuclear system under study no additional narrow peak appears in the oblique field. This result demonstrates that in the GaAsN alloys the hyperfine interaction of the localized electron with the single nucleus of the paramagnetic center remains strong even at room temperature. For a theoretical description of the experiment, we have extended the theory of spin dependent recombination via deep paramagnetic centers with the nuclear angular momentum I 1/2 developed previously for the particular case of the longitudinal field. The calculated curves r(B) J(B) agree with the approximate description of the experimental dependences as a sum of two Lorentzians, and an additional narrow shifted peak does not appear in the computation as well.", "author_names": [ "E L Ivchenko", "Leonid Bakaleinikov", "Mikhail Mikhailovich Afanasiev", "Vladimir K Kalevich" ], "corpus_id": 119287634, "doc_id": "119287634", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Spin dependent recombination in GaAs1 xNx alloys at oblique magnetic field", "venue": "", "year": 2016 }, { "abstract": "A new series of oxynitrides LaVO3 xNx (0 x 0.9) has been synthesized and their electrical and magnetic properties studied. Contrary to the oxides involving the mixed valence VIII VIV, no semiconductor metal transition is observed and all the compounds remain p type semiconductors.", "author_names": [ "P Antoine", "R Assabaa", "P L'haridon", "Roger G Marchand", "Yves Laurent", "Claude Michel", "Bernard Raveau" ], "corpus_id": 98239889, "doc_id": "98239889", "n_citations": 38, "n_key_citations": 1, "score": 0, "title": "Transport properties of the new perovskite type LaVO3=xNx Oxynitrides", "venue": "", "year": 1989 }, { "abstract": "Magnetophotoluminescence measurements show that the electron effective mass and the exciton radius in hydrogen irradiated GaAs 1 x N x vary continuously as a function of the hydrogen dose until they recover the values ofN free GaAs. First principles calculations account for the experimental findings through the formation of a specific N dihydrogen complex, which leads to the removal of the electron localization caused by N incorporation into GaAs.", "author_names": [ "Antonio Polimeni", "G Baldasarri Hoger von Hogersthal", "Francesco Masia", "Andrea Frova", "M Capizzi", "Simone Sanna", "Vincenzo Fiorentini", "Peter J Klar", "Wolfgang Stolz" ], "corpus_id": 120239786, "doc_id": "120239786", "n_citations": 31, "n_key_citations": 0, "score": 0, "title": "Tunable variation of the electron effective mass and exciton radius in hydrogenated GaAs1 xNx", "venue": "", "year": 2004 }, { "abstract": "The electron effective mass, m* e and exciton radius, r e x c have been derived in GaAs 1 x N x (x 0.2% by magneto photoluminescence measurements. With increasing nitrogen concentration, m* e and r e x c undergo a rapid increase and squeezing, respectively, already for x 0.1% Furthermore, in a hydrogen irradiated GaAs 1 x N x sample, the band gap widening induced by H maps on a profound modification of the conduction band. m* e (r e x c decreases (increases) with increasing H dose, until the GaAs value is obtained. First principle calculations show that the formation of a specific N H 2 dihydrogen complex leads to the removal of the electron localization caused by N incorporation in GaAs.", "author_names": [ "Antonio Polimeni", "Francesco Masia", "Giorgio Baldassarri Hoger von Hogersthal", "Andrea Frova", "M Capizzi", "Simone Sanna", "Vincenzo Fiorentini", "Peter J Klar", "Wolfgang Stolz" ], "corpus_id": 123400583, "doc_id": "123400583", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Tuning of the electron effective mass and exciton wavefunction size in GaAs1 xNx", "venue": "", "year": 2004 }, { "abstract": "The chemical processes of formation and decomposition of narrow gap nitrides InN and GaAs1 xNx under ion bombardment have been investigated by Auger electron spectroscopy. It is shown that, due to chemical instability, a large fraction of InN decomposes with formation of metal clusters under ion bombardment. It is established that bombardment of GaAs with a beam of N2+ and Ar+ ions makes it possible to obtain a chemically homogeneous GaAs1 xNx solid solution with a high nitrogen content (x 0.1) whereas implantation of only N2+ ions leads to the formation of a mixture of GaN, GaAsN, and GaAs phases. It is concluded that secondary ion cascades, induced by heavy ions, stimulate nitridation reaction, homogenize the spatial atomic distribution, and shift the dynamic equilibrium to the formation of a single phase solution.", "author_names": [ "V M Mikushkin", "V V Bryzgalov", "Yu S Gordeev", "Valery Yu Davydov" ], "corpus_id": 123141020, "doc_id": "123141020", "n_citations": 6, "n_key_citations": 1, "score": 0, "title": "Formation and decomposition of nitrides under ion bombardment", "venue": "", "year": 2008 }, { "abstract": "The modification of GaAs with a 2500 eV beam containing N2+ and Ar+ ions is examined with Auger electron spectroscopy. Most implanted nitrogen atoms are found to react with the matrix, substituting arsenic atoms to produce a several nanometer thick layer of the single phase GaAs1 xNx (x=6% solid solution. The GaN phase is absent. Displaced arsenic atoms and nitrogen atoms unreacted with the matrix are present in the layer and on its surface. The former segregate, whereas the latter form molecules.", "author_names": [ "Yu S Gordeev", "V V Bryzgalov", "Boris Makarenko", "V M Mikushkin", "Samuil G Konnikov", "Pavel N Brunkov", "V M Ustinov", "Alexey E Zhukov" ], "corpus_id": 120050116, "doc_id": "120050116", "n_citations": 3, "n_key_citations": 1, "score": 0, "title": "Modification of GaAs by medium energy N2+ ions", "venue": "", "year": 2003 }, { "abstract": "We present a study of the optical properties of double quantum wells of In0.3Ga0.7As1 xNx/GaAs. The nitrogen composition, x, lies between 2 10 3 and 9.5 10 3. Temperature dependence of time integrated photoluminescence (PL) and time resolved PL have been investigated. The temperature dependences of the PL energy and the linewidth are correlated, and they show that the carriers are localised at low temperature. Consistently the energy dependence of decay time across the PL line is analysed in terms of mobility edge. The carrier localisation at low temperature is due to alloy disorder in the wells which induces potential fluctuations. The PL linewidth increases with temperature. This linewidth is also strongly increased by the increase of the N composition. We attribute this behaviour to an enhanced coupling of the carriers with LO phonons. We deduce from these results that N incorporation increases the polar character of the III V compound.", "author_names": [ "Romuald Intartaglia", "T Taliercio", "Pierre Valvin", "Guilhem Almuneau", "Pierre Lefebvre", "Thierry Guillet", "Thierry Bretagnon", "Bernard Gil" ], "corpus_id": 96337800, "doc_id": "96337800", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Longitudinal optical phonon broadening due to nitrogen atom incorporation in InGaAsN/GaAs quantum wells", "venue": "", "year": 2005 }, { "abstract": "Results are given for a study of the TiLa, TiLi, and NKa x ray emission bands in TiC1 xNx compounds (x from 0.038 to 0.930) These spectra served as the basis for a discussion of the structure of the energy bands of TiC TiN solid solutions and the evaluation of the validity of various theoretical models. The possibility of determining the composition of solid carbonitride alloys by analysis of the intensity of the x ray emission bands was examined.", "author_names": [ "Artem V Ezhov", "V M Cherkashenko", "B V Mitrofanov", "Ernst Z Kurmaev" ], "corpus_id": 55417168, "doc_id": "55417168", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Ultrasoft x ray emission spectra of the components in complete titanium nitrides", "venue": "", "year": 1989 }, { "abstract": "Here SnO2/LaFeO3 XNX composite was fabricated using a wet chemical method and was applied to pollutants degradation and gas sensing for the first time. The composite exhibits high performance for photocatalytic degradation of Rhodamine B (RhB) dye and selectivity sensing of various gases. On the basis of the completed experiments, the improved RhB degradation and selective gas sensing performance resulted from the extended optical absorption via N2 incorporated surface states and enhanced charge separation via coupling SnO2. Using the scavengers trapping experiments, the superoxide radical (O2* was investigated as the major scavenger involved in the degradation of RhB over SnO2/LaFeO3 XNX composite. In this paper, the probable reaction steps involved in the RhB dye degradation over SnO2/LaFeO3 XNX composite are proposed. This work will provide reasonable strategies to fabricate LaFeO3 based proficient and stable catalysts for environmental purification. In addition, the result of the selectivity of gas performance is also presented.", "author_names": [ "Xi-tao Yin", "Davoud Dastan", "Fa-yu Wu", "Jianshu Li" ], "corpus_id": 201019098, "doc_id": "201019098", "n_citations": 52, "n_key_citations": 0, "score": 1, "title": "Facile Synthesis of SnO2/LaFeO3 XNX Composite: Photocatalytic Activity and Gas Sensing Performance", "venue": "Nanomaterials", "year": 2019 }, { "abstract": "Graphitic carbon nitrides (CNs) are potential candidate materials for the electro catalytic industry due to their unique physical and chemical properties. However, to date, a full understanding of the electro catalytic properties of CNs is still lacking. Herein, by using density functional theory calculations, we systematically investigate the catalytic performances in the hydrogen evolution reaction (HER) oxygen evolution reaction (OER) N2 reduction reaction (NRR) and CO2 reduction reaction (CO2RR) of monolayer graphitic carbon nitrides (C1 xNx) C3N (x 1/4) C2N (x 1/3) and g C3N4 (x 4/7) We also evaluated the NRR activity of B doped C1 xNx, and the CO2RR activity of Cu and Pd modified C1 xNx. The cohesive energy and ab initio molecular dynamics (AIMD) results show that C3N, C2N, and g C3N4 are stable at room temperature. The C3N C1 site is predicted to deliver the best HER catalytic performance with a reaction Gibbs free energy (DGH* of 0.03 eV (close to the ideal value (0 eV) Among the studied C1 xNx materials, the C3N C2 site is predicted to possess a favorable eOER of 0.82 V for OER. Pure C3N, C2N, and g C3N4 are not suitable for NRR and CO2RR. Due to the strong hybridization between the N 2p orbital and the B 2p orbital, the NRR performances of B doped BN C2N, BN C3N, and BN g C3N4 are greatly enhanced, with corresponding overpotential eNRR of 0.57 V, 0.70 V, and 0.72 V, respectively. The transition metals Cu and Pd can enhance the CO2RR activity of C3N, C2N, and g C3N4. The limiting potentials UL of pure C3N, C2N, and g C3N4 are 0.96 V, 0.86 V, and 2.37 V, respectively, while these values are 0.63 V, 0.68 V, and 0.77 V with Cu or Pd modification. This work provides deep understanding of the catalytic properties of monolayer C1 xNx and guidance for synthesizing higher activity catalysts in the future.", "author_names": [ "Yuwen Cheng", "Yan Song", "Yumin Zhang" ], "corpus_id": 212730993, "doc_id": "212730993", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A systematic investigation of the catalytic performances of monolayer carbon nitride nanosheets C1 xNx.", "venue": "Physical chemistry chemical physics PCCP", "year": 2020 } ]

[ { "abstract": "The electron transport properties of atomically thin semiconductors such as MoS2 have attracted significant recent scrutiny and controversy. In this work, the scattering mechanisms responsible for limiting the mobility of single layer semiconductors are evaluated. The roles of individual scattering rates are tracked as the 2D electron gas density is varied over orders of magnitude at various temperatures. From a comparative study of the individual scattering mechanisms, we conclude that all current reported values of mobilities in atomically thin transition metal dichalcogenide semiconductors are limited by ionized impurity scattering. When the charged impurity densities are reduced, remote optical phonon scattering will determine the ceiling of the highest mobilities attainable in these ultrathin materials at room temperature. The intrinsic mobilities will be accessible only in clean suspended layers, as is also the case for graphene. Based on the study, we identify the best choices for surrounding dielectrics that will help attain the highest mobilities.", "author_names": [ "N Ma", "Debdeep Jena" ], "corpus_id": 2432766, "doc_id": "2432766", "n_citations": 191, "n_key_citations": 9, "score": 1, "title": "Charge Scattering and Mobility in Atomically Thin Semiconductors", "venue": "", "year": 2014 }, { "abstract": "The transition metal dichalcogenides have attracted a lot of attention as a possible stepping stone toward atomically thin and flexible field effect transistors. One key parameter to describe the charge transport is the time between two successive scattering events the transport scattering time. In a recent report, we have shown that it is possible to use density functional theory to obtain the band structure of two dimensional semiconductors in presence of field effect doping. Here, we report a simple method to extract the scattering time from the experimental conductivity and from the knowledge of the band structure. We apply our approach to monolayers and multilayers of MoS$_2$ MoSe$_2$ MoTe$_2$ WS$_2$ and WSe$_2$ in presence of a gate. In WS$_2$ for which accurate measurements of mobility have been published, we find that the scattering time is inversely proportional to the density of states at the Fermi level. Finally, we show that it is possible to identify the critical doping at which different valleys start to be occupied from the doping dependence of the conductivity.", "author_names": [ "Thomas Brumme", "Matteo Calandra", "Francesco Mauri" ], "corpus_id": 119267677, "doc_id": "119267677", "n_citations": 12, "n_key_citations": 1, "score": 0, "title": "Determination of scattering time and of valley occupation in transition metal dichalcogenides doped by field effect", "venue": "", "year": 2016 }, { "abstract": "Incorporation of tetramethylammonium iodide into conjugated D A polymer thin film leads to remarkable enhancement of charge mobility. Organic semiconductors with high charge carrier mobilities are crucial for flexible electronic applications. Apart from designing new conjugated frameworks, different strategies have been explored to increase charge carrier mobilities. We report a new and simple approach to enhancing the charge carrier mobility of DPP thieno[3,2 b]thiophene conjugated polymer by incorporating an ionic additive, tetramethylammonium iodide, without extra treatments into the polymer. The resulting thin films exhibit a very high hole mobility, which is higher by a factor of 24 than that of thin films without the ionic additive under the same conditions. On the basis of spectroscopic grazing incidence wide angle x ray scattering and atomic force microscopy studies as well as theoretical calculations, the remarkable enhancement of charge mobility upon addition of tetramethylammonium iodide is attributed primarily to an inhibition of the torsion of the alkyl side chains by the presence of the ionic species, facilitating a more ordered lamellar packing of the alkyl side chains and interchain p p interactions.", "author_names": [ "Hewei Luo", "Chenmin Yu", "Zitong Liu", "Guanxin Zhang", "Hua Geng", "Yuanping Yi", "Katharina Broch", "Yuanyuan Hu", "Aditya Sadhanala", "Lang Jiang", "Penglin Qi", "Zhengxu Cai", "Henning Sirringhaus", "Deqing Zhang" ], "corpus_id": 18228802, "doc_id": "18228802", "n_citations": 104, "n_key_citations": 0, "score": 0, "title": "Remarkable enhancement of charge carrier mobility of conjugated polymer field effect transistors upon incorporating an ionic additive", "venue": "Science Advances", "year": 2016 }, { "abstract": "Clean interface and low contact resistance are crucial requirements in two dimensional (2D) materials to preserve their intrinsic carrier mobility. However, atomically thin 2D materials are sensitive to undesired Coulomb scatterers such as surface/interface adsorbates, metal to semiconductor Schottky barrier (SB) and ionic charges in the gate oxides, which often limits the understanding of the charge scattering mechanism in 2D electronic systems. Here, we present the effects of hafnium dioxide (HfO2) high k passivation and SB height on the low frequency (LF) noise characteristics of multilayer molybdenum ditelluride (MoTe2) transistors. The passivated HfO2 passivation layer significantly suppresses the surface reaction and enhances dielectric screening effect, resulting in an excess electron n doping, zero hysteresis, and substantial improvement in carrier mobility. After the high k HfO2 passivation, the obtained LF noise data appropriately demonstrates the transition of the Coulomb scattering mechanism from the SB contact to the channel, revealing the significant SB noise contribution to the 1/f noise. The substantial excess LF noise in the subthreshold regime is mainly attributed to the excess metal to MoTe2 SB noise and is fully eliminated at the high drain bias regime. This study provides a clear insight into the origin of electronic signal perturbation in 2D electronic systems.", "author_names": [ "Min-Kyu Joo", "Yoojoo Yun", "Hyunjin Ji", "Dongseok Suh" ], "corpus_id": 53568616, "doc_id": "53568616", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Coulomb scattering mechanism transition in 2D layered MoTe2: effect of high k passivation and Schottky barrier height.", "venue": "Nanotechnology", "year": 2019 }, { "abstract": "Simultaneously achieving higher carriers concentration and mobility is a technical challenge against up scaling the transparent conductive performances of transparent conductive oxides. Utilizing one order higher dense ~1 x 1011 cm 3) plasmas (in comparison to the conventional direct current plasmas) highly c axis oriented Al doped ZnO films have been prepared with precise control over relative composition and chemical states of constituting elements. Tailoring of intrinsic (O vacancies) and extrinsic (ionic Al and zero valent Al) dopants provide simultaneous enhancement in mobility and concentration of charge carriers. Room temperature resistivity as low as 4.89 x 10 4 O cm along the carrier concentration 5.6 x 1020 cm 3 is obtained in 200 nm thick transparent films. Here, the control of atomic Al reduces the charge trapping at grain boundaries and subdues the effects of grain boundary scattering. A mechanism based on the correlation between electron hole interaction and carrier mobility is proposed for degenerately doped wide band gap semiconductors.", "author_names": [ "Manish Kumar", "Long Wen", "Bibhuti Bhusan Sahu", "Jeon Geon Han" ], "corpus_id": 116939160, "doc_id": "116939160", "n_citations": 43, "n_key_citations": 0, "score": 0, "title": "Simultaneous enhancement of carrier mobility and concentration via tailoring of Al chemical states in Al ZnO thin films", "venue": "", "year": 2015 }, { "abstract": "In this work, we have applied the Airy Function Transfer Matrix Method to provide a numerical description of the charge scattering mechanisms taking place at the grain boundaries in polycrystalline, degenerately Al doped ZnO (ZnO:Al) films, one of the most studied Transparent Conductive Oxides (TCOs) By discretizing the potential barrier at the grain boundary into linear segments, an accurate calculation of the electron tunneling probability through the grain boundaries has been obtained. Conversely to analytical models based on the Wentzel Kramers Brillouin (WKB) approximation, our new approach is valid for any doping level. We thus provide a complete model that allows a comprehensive explanation of carrier transport in highly doped semiconductors, for which charge tunneling across grain boundaries cannot be neglected. We have tested our model with ZnO:Al thin films prepared by different physical and chemical deposition techniques, namely, sputtering, atomic layer deposition and atmospheric pressure spatial atomic layer deposition. A linear relationship between the trap density at the grain boundaries and carrier density has been extracted by fitting our model to Hall mobility data for the different samples. Our results provide guidance on how to adapt the deposition conditions to obtain high quality materials, with an optimum ratio between optical and electrical properties as required for specific applications.", "author_names": [ "V Nguyen", "Ulrich Gottlieb", "Anthony Valla", "Delfina Munoz", "Daniel Bellet", "David Munoz-Rojas" ], "corpus_id": 139290915, "doc_id": "139290915", "n_citations": 29, "n_key_citations": 1, "score": 0, "title": "Electron tunneling through grain boundaries in transparent conductive oxides and implications for electrical conductivity: the case of ZnO:Al thin films", "venue": "", "year": 2018 }, { "abstract": "High molecular symmetry is always observed in high performance organic semiconductors. However, whether it is an essential factor for molecular design is unclear. In this work, we designed and synthesized three quinoidal isomers, QBTT o, QBTT i, and QBTT s, with different sulfur orientations and a stable E configuration to investigate the relationship between the structure symmetry and organic thin film transistor performance. We found that QBTT o and QBTT i with high C2h symmetry exhibit electron mobilities of 0.02 and 0.15 cm2 V 1 s 1, respectively, while QBTT s exhibits an unexpectedly high electron mobility of 0.32 cm2 V 1 s 1 with Ion/Ioff ratios of =106. The enhanced electron mobilities from QBTT o and QBTT i to QBTT s can be attributed to the different sulfur orientations, especially, molecular symmetry. The thin film microstructures of three QBTTs were systematically investigated by grazing incidence wide angle X ray scattering, near edge X ray absorption fine structure spectroscopy, atomic force", "author_names": [ "Longbin Ren", "Dafei Yuan", "Eliot Gann", "Yuan Guo", "Lars Thomsen", "Christopher R McNeill", "Chong-an Di", "Yuanping Yi", "Xiaozhang Zhu", "Daoben Zhu" ], "corpus_id": 99688143, "doc_id": "99688143", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "Critical Role of Molecular Symmetry for Charge Transport Properties: A Paradigm Learned from Quinoidal Bithieno[3,4 b]thiophenes", "venue": "", "year": 2017 }, { "abstract": "The design and synthesis of new dye/pigment based semiconductors have made a significant contribution to the development of organic electronics. However, there are few detailed studies on the comparison of isomeric dye/pigment molecules, which play an important role in revealing the molecular structure property device performance relationships. In this study, we, for the first time, compared the thermal stability, optical, electrochemical, molecular assembling and charge transport properties of isomeric angular and linear shaped carbazoledioxazine derivatives, namely Ang CZ and Lin CZ, respectively. While the molecular shapes hardly affect the optical bandgaps and energy levels, they dramatically alter the charge transport characteristics. Accordingly, Lin CZ exhibited a two orders of magnitude higher mobility than Ang CZ, evaluated by thin film transistors (TFTs) Further studies suggested that Lin CZ tends to adopt a denser molecular packing motif and a higher molecular orbital overlapping than Ang CZ which is revealed by grazing incidence wide angle X ray scattering (GIWAXS) atomic force microscopy (AFM) and density functional theory calculations (DFT) More importantly, Lin CZ T, a p extended derivative of Lin CZ, showed a relatively high and stable TFT mobility of over 0.1 cm2 V 1 s 1, which was revealed by using an environmentally benign solvent and a pre aggregation method. Our findings will provide direction for developing more promising molecular semiconductors and organic TFT technology.", "author_names": [ "Yang Wang", "Hiroki Tatsumi", "Rikuo Otsuka", "Takehiko Mori", "Tsuyoshi Michinobu" ], "corpus_id": 139222453, "doc_id": "139222453", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Highly stable, green solvent processable organic thin film transistors: angular vs. linear shaped carbazoledioxazine derivatives", "venue": "", "year": 2018 }, { "abstract": "Thin film transistors based on regioregular poly(3 hexylthiophene) (PHT) and poly(3 decylthiophene) (PDT) and their binary blends were investigated and the blend composition dependence of the charge carrier mobility was determined. The field effect mobility of holes (mh) in a series of 10 binary blends of poly(3 hexylthiophene) (mh 0.02 cm2/(V s) and poly(3 decylthiophene) (mh 8 x 10 5 cm2/(V s) was found to be relatively high (2 x 10 3 cm2/(V s) and constant over a broad composition range (5 80 wt PDT) Above 80% PDT, the hole mobility decreased exponentially with composition. Atomic force microscopy of the homopolymers and blends confirmed the absence of phase separation in the blends. A similar interlayer d spacing that is intermediate between those of the homopolymers is implied by the constant hole mobility in the single phase crystalline blends of 5 80 wt PDT. These results demonstrate that blends of conjugated polymers are alloy semiconductors in which high and tunable charge carrier mob.", "author_names": [ "Amit Babel and", "Samson A Jenekhe" ], "corpus_id": 95636081, "doc_id": "95636081", "n_citations": 67, "n_key_citations": 0, "score": 0, "title": "Field Effect Mobility of Charge Carriers in Blends of Regioregular Poly(3 alkylthiophene)s", "venue": "", "year": 2003 }, { "abstract": "We report structural and electrical transport properties of a family of p stacking soluble organic semiconductors, N,N' dialkyl 3,4,9,10 perylene tetracarboxylic diimides (alkyl pentyl [1] octyl [2] and dodecyl [3] The structures of evaporated polycrystalline films of 1 3 were studied using X ray diffraction and atomic force microscopy. Films of 1 3 pack similarly with the direction of p p overlap in the substrate plane. Organic thin film transistors (OTFTs) based on 1 3 deposited on SiO2 gate dielectric showed linear regime electron mobilities of 0.1, 0.6, and 0.2 cm2/(V s) respectively, corrected for contact resistance. OTFTs of 2 had saturation electron mobilities as high as 1.7 cm2/(V s) with on to off current ratios of 107. Variable temperature measurements were used to examine the charge transport kinetics in the range 80 300 K and revealed (1) thermally activated electron mobilities with activation energies dependent on gate voltage and (2) the presence of well defined isokinetic points, i.e.", "author_names": [ "Reid John Chesterfield", "John C Mckeen", "Christopher R Newman", "Paul C Ewbank", "Demetrio Antonio da Silva Filho", "Jean-Luc Bredas", "Larry L Miller", "and Kent R Mann", "C Daniel Frisbie" ], "corpus_id": 97508590, "doc_id": "97508590", "n_citations": 355, "n_key_citations": 2, "score": 0, "title": "Organic Thin Film Transistors Based on N Alkyl Perylene Diimides: Charge Transport Kinetics as a Function of Gate Voltage and Temperature", "venue": "", "year": 2004 } ]

[ { "abstract": "The quality of human capital is crucial for high tech companies to maintain competitive advantages in knowledge economy era. However, high technology companies suffering from high turnover rates often find it hard to recruit the right talents. In addition to conventional human resource management approaches, there is an urgent need to develop effective personnel selection mechanism to find the talents who are the most suitable to their own organizations. This study aims to fill the gap by developing a data mining framework based on decision tree and association rules to generate useful rules for personnel selection. The results can provide decision rules relating personnel information with work performance and retention. An empirical study was conducted in a semiconductor company to support their hiring decision for indirect labors including engineers and managers with different job functions. The results demonstrated the practical viability of this approach. Moreover, based on discussions among domain experts and data miner, specific recruitment and human resource management strategies were created from the results.", "author_names": [ "Chen-Fu Chien", "Li-Fei Chen" ], "corpus_id": 9172085, "doc_id": "9172085", "n_citations": 376, "n_key_citations": 29, "score": 1, "title": "Data mining to improve personnel selection and enhance human capital: A case study in high technology industry", "venue": "Expert Syst. Appl.", "year": 2008 }, { "abstract": "Data Preparation for Data Mining addresses an issue unfortunately ignored by most authorities on data mining: data preparation. Thanks largely to its perceived difficulty, data preparation has traditionally taken a backseat to the more alluring question of how best to extract meaningful knowledge. But without adequate preparation of your data, the return on the resources invested in mining is certain to be disappointing.Dorian Pyle corrects this imbalance. A twenty five year veteran of what has become the data mining industry, Pyle shares his own successful data preparation methodology, offering both a conceptual overview for managers and complete technical details for IT professionals. Apply his techniques and watch your mining efforts pay off in the form of improved performance, reduced distortion, and more valuable results.On the enclosed CD ROM, you'll find a suite of programs as C source code and compiled into a command line driven toolkit. This code illustrates how the author's techniques can be applied to arrive at an automated preparation solution that works for you. Also included are demonstration versions of three commercial products that help with data preparation, along with sample data with which you can practice and experiment. Offers in depth coverage of an essential but largely ignored subject. Goes far beyond theory, leading you step by step through the author's own data preparation techniques. Provides practical illustrations of the author's methodology using realistic sample data sets. Includes algorithms you can apply directly to your own project, along with instructions for understanding when automation is possible and when greater intervention is required. Explains how to identify and correct data problems that may be present in your application. Prepares miners, helping them head into preparation with a better understanding of data sets and their limitations.", "author_names": [ "Dorian Pyle" ], "corpus_id": 8366862, "doc_id": "8366862", "n_citations": 1535, "n_key_citations": 67, "score": 0, "title": "Data Preparation for Data Mining", "venue": "", "year": 1999 }, { "abstract": "In this paper, the concept of social capital is introduced and illustrated, its forms are described, the social structural conditions under which it arises are examined, and it is used in an analysis of dropouts from high school. Use of the concept of social capital is part of a general theoretical strategy discussed in the paper: taking rational action as a starting point but rejecting the extreme individualistic premises that often accompany it. The conception of social capital as a resource for action is one way of introducing social structure into the rational action paradigm. Three forms of social capital are examined: obligations and expectations, information channels, and social norms. The role of closure in the social structure in facilitating the first and third of these forms of social capital is described. An analysis of the effect of the lack of social capital available to high school sophomores on dropping out of school before graduation is carried out. The effect of social capital within the family and in the community outside the family is examined.", "author_names": [ "James S Coleman" ], "corpus_id": 51859022, "doc_id": "51859022", "n_citations": 30335, "n_key_citations": 2823, "score": 0, "title": "Social Capital in the Creation of Human Capital", "venue": "American Journal of Sociology", "year": 1988 }, { "abstract": "We develop a two country, two sector model of trade where the only difference between the two countries is their distribution of human capital endowments. We show that even if the two countries have identical aggregate human capital endowments the pattern of trade depends on the properties of the two human capital distributions. We also show that the two distributions of endowments also completely determine the effects of trade on income inequality. Then, we prove that there are long term gains from trade if the marginal utility of income is constant or as long as losers from trade are compensated by winners. Finally, we look at a simple majority voting model. It turns out depending on the distribution of human capital, autarky and free trade with and without compensation may be the outcome of majority voting. JEL Code: F1.", "author_names": [ "Spiros P Bougheas", "Raymond Riezman" ], "corpus_id": 53459081, "doc_id": "53459081", "n_citations": 1794, "n_key_citations": 148, "score": 0, "title": "Human Capital", "venue": "Encyclopedia of Social Network Analysis and Mining. 2nd Ed.", "year": 2018 }, { "abstract": "Data mining is a process of extracting knowledge from large databases. Knowledge is appreciated as ultimate power now a days and considered as very important factor for the success of any organization because it has impacted the role of people working in that organization. In last decade, the higher education sector in India has grown radically. Thus HR management has implemented various improvements and it is hard for organizations to retain a motivated and competent workforce. Clever investment in human resource and its effective management has become very necessary today. HRM in higher education sector is further complicated by qualitative and multidimensional definition of \"performance\" of an academician (employee) in this sector. This paper aims to propose a model for predicting employee performance in higher education institutes with the help of classification and prediction techniques of data mining. The objective of model is to facilitate decisions in a challenging and emerging field of HRM in higher education sector.", "author_names": [ "Mugdha Sharma", "Ankit Goyal" ], "corpus_id": 17841343, "doc_id": "17841343", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "An application of data mining to improve personnel performance evaluation in higher education sector in India", "venue": "2015 International Conference on Advances in Computer Engineering and Applications", "year": 2015 }, { "abstract": "In this paper, we analyze empirically the relation between the growth of new technology based firms and the human capital of founders, with the aim of teasing out the \"wealth\" and \"capability\" effects of human capital. For this purpose, we take advantage of a new data set relating to a sample composed of 506 Italian young firms that operate in high tech industries in both manufacturing and services. In accordance with competence based theories, the econometric estimates show that the nature of the education and of the prior work experience of founders exerts a key influence on growth. In fact, founders' years of university education in economic and managerial fields and to a lesser extent in scientific and technical fields positively affect growth while education in other fields does not. Similarly prior work experience in the same industry of the new firm is positively associated with growth while prior work experience in other industries is not. Furthermore, it is the technical work experience of founders as opposed to their commercial work experience that determines growth. The fact that within the founding team there are individuals with prior entrepreneurial experiences also results in superior growth. Lastly, we provide evidence that there are synergistic gains from the combination of the complementary capabilities of founders relating to (i) economic managerial and scientific technical education and (ii) technical and commercial industry specific work experiences. We conclude that the human capital of founders of new technology based firms is not just a proxy for personal wealth.", "author_names": [ "Massimo G Colombo", "Luca Grilli" ], "corpus_id": 54700141, "doc_id": "54700141", "n_citations": 1039, "n_key_citations": 92, "score": 0, "title": "Founders' human capital and the growth of new technology based firms: A competence based view", "venue": "", "year": 2003 }, { "abstract": "Investigates the probability of new firm success or failure based on factors that can be observed at the time of initial startup. Four categories of human and financial capital were considered: (1) general human capital which may reflect the extent to which the entrepreneur has had the opportunity to develop relevant skills and contacts including the entrepreneur's race, gender, education; (2) management know how which reflects management skills and knowledge including the entrepreneur's own skills or skills available through advisors or partners; (3) industry specific know how which reflects specific experience in other businesses; and (4) financial capital which can create a buffer against random shocks and allow the pursuit of more capital intensive strategies. Data were gathered from 1,053 responses from questionnaires sent to owners of firms established within the previous 1 1/2 years. The firms, from a variety of industry sectors and geographical regions in the United States, were tracked over a three year period, during the years 1985 to 1987. Findings show that measures of general human capital impacted both firm survival and growth. One exception to this was gender female owned enterprises were less likely to grow, but just as likely to survive. Amount of initial capital was also shown to influence both survival and growth. However, management know how, number of partners, and having parents who had owned a business had a more limited impact. Significant effects were not found for management level, prior employment in non profit organizations, not having been in the labor force, and the use of professional advisors. It should be possible to predict the future success or failure of new ventures using the four categories of human and financial capital utilized in this study (after dropping the insignificant components of personal characteristics) These measures are readily identifiable at startup, and in some cases potential problems can be identified and remedied. (SFL)", "author_names": [ "Arnold C Cooper", "F Javier Gimeno-Gascon", "Carolyn Y Woo" ], "corpus_id": 167974162, "doc_id": "167974162", "n_citations": 1620, "n_key_citations": 87, "score": 0, "title": "Initial human and financial capital as predictors of new venture performance", "venue": "", "year": 1994 }, { "abstract": "Employing a sample of 180 entrepreneurial high technology ventures based in the United Kingdom, we examine the effects of social capital in key customer relationships on knowledge acquisition and knowledge exploitation. Building on the relational view and on social capital and knowledge based theories, we propose that social capital facilitates external knowledge acquisition in key customer relationships and that such knowledge mediates the relationship between social capital and knowledge exploitation for competitive advantage. Our results indicate that the social interaction and network ties dimensions of social capital are indeed associated with greater knowledge acquisition, but that the relationship quality dimension is negatively associated with knowledge acquisition. Knowledge acquisition is, in turn, positively associated with knowledge exploitation for competitive advantage through new product development, technological distinctiveness, and sales cost efficiency. Further, our results provide evidence that knowledge acquisition plays a mediating role between social capital and knowledge exploitation. Copyright (c) 2001 John Wiley Sons, Ltd.", "author_names": [ "Helena Yli-Renko", "Erkko Autio", "Harry J Sapienza" ], "corpus_id": 168037869, "doc_id": "168037869", "n_citations": 2407, "n_key_citations": 161, "score": 0, "title": "SOCIAL CAPITAL, KNOWLEDGE ACQUISITION, AND KNOWLEDGE EXPLOITATION IN YOUNG TECHNOLOGY BASED FIRMS", "venue": "", "year": 2001 }, { "abstract": "Part 1 Foundations of qualitative case study research: the case study approach to research problems types and uses of case study research in education defining a research problem and selecting a case handling theory and literature reviews in case study research. Part 2 mastering qualitative data collection methods: conducting effective interviews being a careful observer mining data from documents. Part 3 Analyzing and reporting case study data: the components of data analysis using special techniques and computers to analyze qualitative data dealing with validity, reliability, and ethics in case study research writing the case study report.", "author_names": [ "Sharan B Merriam" ], "corpus_id": 60728289, "doc_id": "60728289", "n_citations": 5681, "n_key_citations": 652, "score": 0, "title": "Case Study Research in Education A Qualitative Approach", "venue": "", "year": 1991 }, { "abstract": "THE DESIGN OF QUALITATIVE RESEARCH. 1. What is Qualitative Research? 2. Case Studies as Qualtitative Research. 3. Designing the Study and Selecting a Sample. COLLECTING QUALITATIVE DATA. 4. Conducting Effective Interviews. 5. Being a Careful Observer. 6. Mining Data from Documents. 7. Collecting Data in Case Studies. ANALYZING AND REPORTING QUALITATIVE DATA. 8. Analytic Techniques and Data Management. 9. Levels of Analysis. 10. Dealing with Validity, Reliability and Ethics. 11. Writing Reports and Case Studies.", "author_names": [ "Sharan B Merriam" ], "corpus_id": 60630749, "doc_id": "60630749", "n_citations": 16972, "n_key_citations": 3301, "score": 0, "title": "Qualitative research and case study applications in education", "venue": "", "year": 1998 } ]

[ { "abstract": "This paper proposes a new dc ac converter with a reduced number of semiconductor switches and gate drive and control circuit components. A salient feature of this inverter is its pure sinusoidal line to line voltages with no need for output filter. Also, the proposed inverter improves the voltage utilization factor of the input dc supply compared to the four switch three phase inverter (first best topology in the literature from the number of switches point of view) and standard six switch inverter with sine pulsewidth modulation. The proposed inverter is capable of operating with a wide range of output voltages from zero to the full value of the dc input voltage by appropriately altering the instantaneous duty cycle. A three phase universal inverter with only three power switch has been proposed in this paper for the first time ever, to our knowledge. For the purpose of providing a good compromise between fast transient response and stability, a model predictive controller is proposed. All the design expressions have been derived. A comparison with other dc ac converters is given to show the merits of the proposed converter. Finally, satisfactory circuit operation is confirmed by experimental results from a laboratory prototype.", "author_names": [ "Masoud Farhadi", "Mehdi Abapour" ], "corpus_id": 52161636, "doc_id": "52161636", "n_citations": 18, "n_key_citations": 0, "score": 1, "title": "Three Switch Three Phase Inverter With Improved DC Voltage Utilization", "venue": "IEEE Transactions on Industrial Electronics", "year": 2019 }, { "abstract": "This paper proposes an effective model predictive control (MPC) scheme using a modulated optimal vector (MOV) and finite control options for a three phase inverter with an LC filter. Unlike other MPC methods, the proposed MPC strategy exploits the unconstrained optimal vector (OV) of the continuous control set (CCS) MPC to limit the control options for the unconstrained mode. First, the analytical OV is derived based on a least squares optimization. If the input constraints are not violated, the OV is applied with a space vector modulation (SVM) technique like the CCS MPC. Otherwise, the OV is scaled into the MOV and only three control options are online evaluated to reselect the control input. Experiments are conducted on a three phase inverter test bed with a TI TMS320F28335 digital signal processor to validate the improvements of the proposed method, especially the robust performances and fast responses. The comparative results with the FCS MPC show the superior performances of the proposed scheme with smaller steady state error and lower total harmonic distortion due to the analytical OV with SVM, more robustness to parameter uncertainties due to the disturbance observer, and faster dynamic response due to the online reselection of control inputs.", "author_names": [ "Hoach the Nguyen", "Eun-Kyung Kim", "Ik-Pyo Kim", "Han Ho Choi", "Jin-Woo Jung" ], "corpus_id": 20861625, "doc_id": "20861625", "n_citations": 44, "n_key_citations": 6, "score": 0, "title": "Model Predictive Control with Modulated Optimal Vector for a Three Phase Inverter with an LC Filter", "venue": "IEEE Transactions on Power Electronics", "year": 2018 }, { "abstract": "Adding the auxiliary switches to the conventional H bridge inverter is an effective way to eliminate the leakage current for transformerless PV systems, such as H5, H6, etc. Inspired by the newly developed embedded switch H6 topology, a novel embedded switch inverter (ESI) is proposed in this paper for three phase transformerless PV systems. First, the operation principle and characteristics of the proposed ESI are analyzed. Second, the common mode model of the three phase ESI is established, based on which the main factors that affect the leakage current are discussed. The finding reveals that the switching states with conventional modulation strategy result in high frequency common mode voltage, which is the source of leakage current. In order to solve the problem, a new modulation strategy is presented for ESI to eliminate the high frequency leakage current. Finally, the time domain simulation and the experimental tests are carried out. The results verify the effectiveness of the proposed solution.", "author_names": [ "Xiaoqiang Guo", "Yong Yang", "Tieying Zhu" ], "corpus_id": 27532469, "doc_id": "27532469", "n_citations": 52, "n_key_citations": 1, "score": 0, "title": "ESI: A Novel Three Phase Inverter With Leakage Current Attenuation for Transformerless PV Systems", "venue": "IEEE Transactions on Industrial Electronics", "year": 2018 }, { "abstract": "This letter presents a three phase voltage source inverter (VSI) topology to reduce the common mode (CM) voltage and electromagnetic interference (EMI) of electric motor drives. Instead of using filters, active or passive, or specific pulse width modulated (PWM) techniques to reduce the CM voltage, the proposed topology has inherently less CM voltage generation. With the addition of two switches placed in series on the dc lines, this topology effectively reduces the CM voltage during zero switching states by \"floating\" the inverter from the dc source. This topology can be implemented with any PWM method and does not add any additional complexity to the standard control techniques. The operation and CM reduction capability of the topology is first demonstrated in simulation and then verified with experimental results. A comparison of both common mode voltage and EMI is made to a conventional three phase VSI to demonstrate the effectiveness of the proposed topology.", "author_names": [ "Casey T Morris", "Di Han", "Bulent Sarlioglu" ], "corpus_id": 31701197, "doc_id": "31701197", "n_citations": 93, "n_key_citations": 3, "score": 0, "title": "Reduction of Common Mode Voltage and Conducted EMI Through Three Phase Inverter Topology", "venue": "IEEE Transactions on Power Electronics", "year": 2017 }, { "abstract": "When control schemes based on finite control set model predictive control are experimentally implemented, a large amount of calculations is required, introducing a considerable time delay in the actuation. This delay can deteriorate the performance of the system if not considered in the design of the controller. In this paper, the problem is described, and the solution to this issue is clearly explained using a three phase inverter as an example. Experimental results to validate this solution are shown.", "author_names": [ "Patricio Cortes", "Jose R Rodriguez", "Cesar Bastos da Silva", "Alexis Flores" ], "corpus_id": 206701871, "doc_id": "206701871", "n_citations": 649, "n_key_citations": 11, "score": 0, "title": "Delay Compensation in Model Predictive Current Control of a Three Phase Inverter", "venue": "IEEE Transactions on Industrial Electronics", "year": 2012 }, { "abstract": "High dc voltage utilization is one of the important requirements in a three phase inverter. Under some carrier based pulse width modulations (PWMs) the dc voltage utilization can reach the same maximum as that under the space vector modulation. But the third harmonic component of common mode voltage (CMV) will be increased markedly while using these carrier based PWMs in inverters. To improve the situation, this paper proposes that a midpoint fluctuation carrier (MFC) scheme should be used in the three phase inverter. The MFC is formed by adding a midpoint fluctuation signal on the standard symmetrical triangular carrier. By analyzing the linear modulation region of the midpoint fluctuation signals, a minimum fluctuant signal in the linear modulation region is designed in the paper. Compared with the use of other conventional schemes in the three phase inverter, the use of minimum MFC scheme has higher fundamental amplitude in the output line voltage and smaller magnitude of the third harmonic in the CMV. The feasibility and validity of the MFC are proved by experiment results in a three phase inverter.", "author_names": [ "Jin Huang", "Quanhui Liu", "Xulong Wang", "Kaicheng Li" ], "corpus_id": 27625869, "doc_id": "27625869", "n_citations": 22, "n_key_citations": 1, "score": 0, "title": "A Carrier Based Modulation Scheme to Reduce the Third Harmonic Component of Common Mode Voltage in a Three Phase Inverter Under High DC Voltage Utilization", "venue": "IEEE Transactions on Industrial Electronics", "year": 2018 }, { "abstract": "It is well known that predictive control methods can be affected by the presence of modeling errors. The extent to which finite control set model predictive control (FCS MPC) is influenced by parametric uncertainties is a recurrent concern at the moment of evaluating the viability of this method for power electronics applications. This paper proposes an analytic approach to examine the influence of model parametric uncertainties on the prediction error of FCS MPC for current control in a three phase two level inverter. The analysis shows that the prediction error is not only determined by parametric mismatch but also by the instantaneous values of load current and inverter output voltage. This implies that within each sampling period of the predictive algorithm several conditions of prediction error are generated, as multiple voltage vectors are evaluated. Simulation and experimental results are provided and discussed showing the effects of inaccuracies in the modeling of load resistance and inductance parameters on the performance of FCS MPC. Even though steady state performance is noticeably affected with parameter changes, especially when the load inductance is overestimated by the model, its fast transient step response is less affected by parameter changes.", "author_names": [ "Hector A Young", "Marcelo A Perez", "Jose R Rodriguez" ], "corpus_id": 2116213, "doc_id": "2116213", "n_citations": 116, "n_key_citations": 6, "score": 0, "title": "Analysis of Finite Control Set Model Predictive Current Control With Model Parameter Mismatch in a Three Phase Inverter", "venue": "IEEE Transactions on Industrial Electronics", "year": 2016 }, { "abstract": "Small signal stability is an important concern in three phase inverter based ac power systems. The impedance based approach based on the generalized Nyquist stability criterion (GNC) can analyze the stability related with the medium and high frequency modes of the systems. However, the GNC involves the right half plane (RHP) pole calculation of return ratio transfer function matrices, which cannot be avoided for stability analysis of complicated ac power systems. Therefore, it necessitates the detailed internal control information of the inverters, which is not normally available for commercial inverters. To address this issue, this paper introduces the component connection method (CCM) in the frequency domain for stability analysis in the synchronous d q frame, by proposing a method of deriving the impedance matrix of the connection networks of inverter based ac power systems. Demonstration on a two area system and a microgrid shows that: The CCM enabled approach can avoid the RHP pole calculation of return ratio matrices and enables the stability analysis by using only the impedances of system components, which could be measured without the need for the internal information. A stability analysis method based on d q impedances, the CCM, and the determinant based GNC is also proposed to further simplify the analysis process. Inverter controller parameters can be designed as stability regions in parameter spaces, by repetitively applying the proposed stability analysis method. Simulation and experimental results verify the validity of the proposed stability analysis method and the parameter design approach.", "author_names": [ "Wenchao Cao", "Yiwei Ma", "Liu Yang", "Fei Wang", "Leon M Tolbert" ], "corpus_id": 27273994, "doc_id": "27273994", "n_citations": 54, "n_key_citations": 4, "score": 0, "title": "D Q Impedance Based Stability Analysis and Parameter Design of Three Phase Inverter Based AC Power Systems", "venue": "IEEE Transactions on Industrial Electronics", "year": 2017 }, { "abstract": "This paper presents a speed controller using a fuzzy logic controller (FLC) for indirect field oriented control (IFOC) of induction motor (IM) drives fed by a four switch three phase (FSTP) inverter. In the proposed approach, the IM drive system is fed by an FSTP inverter instead of the traditional six switch three phase (SSTP) inverter for cost effective low power applications. The proposed FLC improves dynamic responses, and it is also designed with reduced computation burden. The complete IFOC scheme incorporating the FLC for IM drives fed by the proposed FSTP inverter is built in MATLAB/Simulink, and it is also experimentally implemented in real time using a DSP DS1103 control board for a prototype 1.1 kW IM. The dynamic performance, robustness, and insensitivity of the proposed FLC with the FSTP inverter fed IM drive is examined and compared to a traditional proportional integral (PI) controller under speed tracking, load disturbances, and parameters variation, particularly at low speeds. It is found that the proposed FLC is more robust than the PI controller under load disturbances, and parameters variation. Moreover, the proposed FSTP IM drive is comparable with a traditional SSTP IM drive, considering its good dynamic performance, cost reduction, and low total harmonic distortion (THD)", "author_names": [ "Mohamed S Zaky", "Mohamed K Metwaly" ], "corpus_id": 19958836, "doc_id": "19958836", "n_citations": 51, "n_key_citations": 1, "score": 0, "title": "A Performance Investigation of a Four Switch Three Phase Inverter Fed IM Drives at Low Speeds Using Fuzzy Logic and PI Controllers", "venue": "IEEE Transactions on Power Electronics", "year": 2017 }, { "abstract": "Three phase inverter based multibus ac power systems could suffer from the harmonic instability issue. The existing impedance based stability analysis method using the Nyquist stability criterion once requires the calculation of right half plane (RHP) poles of impedance ratios, which would result in a heavy computation burden for complicated systems. In order to analyze the harmonic stability of multibus ac systems consisting of both voltage controlled and current controlled inverters without the need for RHP pole calculation, this paper proposes two sequence impedance based harmonic stability analysis methods. Based on the summary of all major connection types including mesh, the proposed Method 1 can analyze the harmonic stability of multibus ac systems by adding the components one by one from nodes in the lowest level to areas in the highest system level, and accordingly, applying the stability criteria multiple times in succession. The proposed Method 2 is a generalized extension of the impedance sum type criterion to be used for the harmonic stability analysis of any multibus ac systems based on Cauchy's theorem. The inverter controller parameters can be designed in the forms of stability regions in the parameter space, by repetitively applying the proposed harmonic stability analysis methods. Experimental results of inverter based multibus ac systems validate the effectiveness of the proposed harmonic stability analysis methods and parameter design approach.", "author_names": [ "Wenchao Cao", "Yiwei Ma", "Fred Wang" ], "corpus_id": 43445701, "doc_id": "43445701", "n_citations": 40, "n_key_citations": 7, "score": 0, "title": "Sequence Impedance Based Harmonic Stability Analysis and Controller Parameter Design of Three Phase Inverter Based Multibus AC Power Systems", "venue": "IEEE Transactions on Power Electronics", "year": 2017 } ]

[ { "abstract": "This paper reports that among known p type oxide semiconductors, tin monoxide (SnO) has a high hole mobility and produces good p type oxide thin film transistors (TFTs) Device quality SnO films were grown epitaxially on (001) yttria stabilized zirconia substrates at 575degC by pulsed laser deposition. These exhibited a Hall mobility of 2.4cm2V 1s 1 at room temperature. Top gated TFTs, using epitaxial SnO channels, exhibited field effect mobilities of 1.3cm2V 1s 1, on/off current ratios of ~102, and threshold voltages of 4.8V.", "author_names": [ "Yoichi Ogo", "Hidenori Hiramatsu", "Kenji Nomura", "Hiroshi Yanagi", "Toshio Kamiya", "Masahiro Hirano", "Hideo Hosono" ], "corpus_id": 120995376, "doc_id": "120995376", "n_citations": 456, "n_key_citations": 3, "score": 1, "title": "p channel thin film transistor using p type oxide semiconductor, SnO", "venue": "", "year": 2008 }, { "abstract": "Initially poorly conducting PbSe nanocrystal solids (quantum dot arrays or superlattices) can be chemically \"activated\" to fabricate n and p channel field effect transistors with electron and hole mobilities of 0.9 and 0.2 square centimeters per volt second, respectively; with current modulations of about 103 to 104; and with current density approaching 3 x 104 amperes per square centimeter. Chemical treatments engineer the interparticle spacing, electronic coupling, and doping while passivating electronic traps. These nanocrystal field effect transistors allow reversible switching between n and p transport, providing options for complementary metal oxide semiconductor circuits and enabling a range of low cost, large area electronic, optoelectronic, thermoelectric, and sensing applications.", "author_names": [ "Dmitri V Talapin", "Christopher B Murray" ], "corpus_id": 19649819, "doc_id": "19649819", "n_citations": 1376, "n_key_citations": 26, "score": 0, "title": "PbSe Nanocrystal Solids for n and p Channel Thin Film Field Effect Transistors", "venue": "Science", "year": 2005 }, { "abstract": "The scaling of complementary metal oxide semiconductor transistors has led to the silicon dioxide layer, used as a gate dielectric, being so thin (1.4?nm) that its leakage current is too large. It is necessary to replace the SiO2 with a physically thicker layer of oxides of higher dielectric constant or 'high K' gate oxides such as hafnium oxide and hafnium silicate. These oxides had not been extensively studied like SiO2, and they were found to have inferior properties compared with SiO2, such as a tendency to crystallize and a high density of electronic defects. Intensive research was needed to develop these oxides as high quality electronic materials. This review covers both scientific and technological issues?the choice of oxides, their deposition, their structural and metallurgical behaviour, atomic diffusion, interface structure and reactions, their electronic structure, bonding, band offsets, electronic defects, charge trapping and conduction mechanisms, mobility degradation and flat band voltage shifts. The oxygen vacancy is the dominant electron trap. It is turning out that the oxides must be implemented in conjunction with metal gate electrodes, the development of which is further behind. Issues about work function control in metal gate electrodes are discussed.", "author_names": [ "John Robertson" ], "corpus_id": 122044323, "doc_id": "122044323", "n_citations": 1386, "n_key_citations": 28, "score": 0, "title": "High dielectric constant gate oxides for metal oxide Si transistors", "venue": "", "year": 2006 }, { "abstract": "Transparent electronic devices formed on flexible substrates are expected to meet emerging technological demands where silicon based electronics cannot provide a solution. Examples of active flexible applications include paper displays and wearable computers. So far, mainly flexible devices based on hydrogenated amorphous silicon (a Si:H) and organic semiconductors have been investigated. However, the performance of these devices has been insufficient for use as transistors in practical computers and current driven organic light emitting diode displays. Fabricating high performance devices is challenging, owing to a trade off between processing temperature and device performance. Here, we propose to solve this problem by using a novel semiconducting material namely, a transparent amorphous oxide semiconductor from the In Ga Zn O system (a IGZO) for the active channel in transparent thin film transistors (TTFTs) The a IGZO is deposited on polyethylene terephthalate at room temperature and exhibits Hall effect mobilities exceeding 10 cm2 V 1 s 1, which is an order of magnitude larger than for hydrogenated amorphous silicon. TTFTs fabricated on polyethylene terephthalate sheets exhibit saturation mobilities of 6 9 cm2 V 1 s 1, and device characteristics are stable during repetitive bending of the TTFT sheet.", "author_names": [ "Kenji Nomura", "Hiromichi Ohta", "Akihiro Takagi", "Toshio Kamiya", "Masahiro Hirano", "Hideo Hosono" ], "corpus_id": 4302869, "doc_id": "4302869", "n_citations": 5272, "n_key_citations": 80, "score": 0, "title": "Room temperature fabrication of transparent flexible thin film transistors using amorphous oxide semiconductors", "venue": "Nature", "year": 2004 }, { "abstract": "The Berkeley short channel IGFET model (BSIM) an accurate and computationally efficient MOS transistor model, and its associated characterization facility for advanced integrated circuit design are described. Both the strong inversion and weak inversion components of the drain current expression are included. In order to speed up the circuit simulation execution time, the dependence of the drain current on the substrate bias has been modeled with a numerical approximation. This approximation also simplifies the transistor terminal charge expressions. The charge model was derived from its drain current counterpart to preserve consistency of device physics. Charge conservation is guaranteed in this model.", "author_names": [ "Bing J Sheu", "Don L Scharfetter", "Ping K Ko", "Min-Chie Jeng" ], "corpus_id": 60947914, "doc_id": "60947914", "n_citations": 557, "n_key_citations": 20, "score": 0, "title": "BSIM: Berkeley short channel IGFET model for MOS transistors", "venue": "", "year": 1987 }, { "abstract": "Graphene has changed from being the exclusive domain of condensed matter physicists to being explored by those in the electron device community. In particular, graphene based transistors have developed rapidly and are now considered an option for post silicon electronics. However, many details about the potential performance of graphene transistors in real applications remain unclear. Here I review the properties of graphene that are relevant to electron devices, discuss the trade offs among these properties and examine their effects on the performance of graphene transistors in both logic and radiofrequency applications. I conclude that the excellent mobility of graphene may not, as is often assumed, be its most compelling feature from a device perspective. Rather, it may be the possibility of making devices with channels that are extremely thin that will allow graphene field effect transistors to be scaled to shorter channel lengths and higher speeds without encountering the adverse short channel effects that restrict the performance of existing devices. Outstanding challenges for graphene transistors include opening a sizeable and well defined bandgap in graphene, making large area graphene transistors that operate in the current saturation regime and fabricating graphene nanoribbons with well defined widths and clean edges.", "author_names": [ "Frank Schwierz" ], "corpus_id": 205446876, "doc_id": "205446876", "n_citations": 2067, "n_key_citations": 46, "score": 0, "title": "Graphene transistors.", "venue": "Nature nanotechnology", "year": 2010 }, { "abstract": "Here we report high performance sub 100 nm channel length graphene transistors fabricated using a self aligned approach. The graphene transistors are fabricated using a highly doped GaN nanowire as the local gate with the source and drain electrodes defined through a self aligned process and the channel length defined by the nanowire size. This fabrication approach allows the preservation of the high carrier mobility in graphene and ensures nearly perfect alignment between source, drain, and gate electrodes. It therefore affords transistor performance not previously possible. Graphene transistors with 45 100 nm channel lengths have been fabricated with the scaled transconductance exceeding 2 mS/mm, comparable to the best performed high electron mobility transistors with similar channel lengths. Analysis of and the device characteristics gives a transit time of 120 220 fs and the projected intrinsic cutoff frequency (f(T) reaching 700 1400 GHz. This study demonstrates the exciting potential of graphene based electronics in terahertz electronics.", "author_names": [ "Lei Liao", "Jingwei Bai", "Rui Cheng", "Yung-chen Lin", "Shanjuan Jiang", "Yongquan Qu", "Yu Huang", "Xiangfeng Duan" ], "corpus_id": 226222, "doc_id": "226222", "n_citations": 163, "n_key_citations": 5, "score": 0, "title": "Sub 100 nm channel length graphene transistors.", "venue": "Nano letters", "year": 2010 }, { "abstract": "Transparent thin film transistors (TTFTs) with an amorphous zinc tin oxide channel layer formed via rf magnetron sputter deposition are demonstrated. Field effect mobilities of 5 15 and 20 50cm2V 1s 1 are obtained for devices post deposition annealed at 300 and 600degC, respectively. TTFTs processed at 300 and 600degC yield devices with turn on voltage of 0 15 and 5 5V, respectively. Under both processing conditions, a drain current on to off ratio greater than 107 is obtained. Zinc tin oxide is one example of a new class of high performance TTFT channel materials involving amorphous oxides composed of heavy metal cations with (n 1)d10ns0 (n4) electronic configurations.", "author_names": [ "Hai Q Chiang", "John F Wager", "Randy Hoffman", "J Y Jeong", "Douglas A Keszler" ], "corpus_id": 15691455, "doc_id": "15691455", "n_citations": 718, "n_key_citations": 14, "score": 0, "title": "High mobility transparent thin film transistors with amorphous zinc tin oxide channel layer", "venue": "", "year": 2005 }, { "abstract": "The effects of bias stress on transistor performance are important when considering nontraditional channel materials for thin film transistors. Applying a gate bias stress to indium gallium zinc oxide transparent thin film transistors was found to induce a parallel threshold voltage shift without changing the field effect mobility or the subthreshold gate voltage swing. The threshold voltage change is logarithmically dependent on the duration of the bias stress implying a charge tunneling mechanism resulting in trapped negative charge screening the applied gate voltage.", "author_names": [ "Arun Suresh", "John F Muth" ], "corpus_id": 121512584, "doc_id": "121512584", "n_citations": 522, "n_key_citations": 6, "score": 0, "title": "Bias stress stability of indium gallium zinc oxide channel based transparent thin film transistors", "venue": "", "year": 2008 }, { "abstract": "Experiments on ultra small metal oxide semiconductor field effect transistors (MOSFETs) less than 100 nm have been widely reported recently. The frequency of carrier scattering events in these ultra small devices is diminished, so that further suppression of carrier scattering may bring these devices close to the regime of ballistic transport. Carrier scattering is suppressed by constructing their channel regions with intrinsic Si and also by low temperature operation. This article proposes the ballistic transport of carriers in MOSFETs, and presents the current voltage characteristics of the ballistic n channel MOSFET. The current is expressed with the elementary parameters without depending on the carrier mobility. It is independent of the channel length and is proportional to the channel width. The current value saturates as the drain voltage is increased and the triode and the pentode operation are specified as in the conventional MOSFET. Similar current voltage characteristics in the ballistic transp.", "author_names": [ "Kenji Natori" ], "corpus_id": 55868736, "doc_id": "55868736", "n_citations": 574, "n_key_citations": 24, "score": 0, "title": "Ballistic metal oxide semiconductor field effect transistor", "venue": "", "year": 1994 } ]

[ { "abstract": "Abstract Reliability of metal interconnects and the integration of inspection and metrology with process tools are advancing rapidly to overcome obstacles in down stream production. A significant drawback associated with metal interconnects which has resulted from the recent trend is the difficulty in obtaining uniform electroplated layer thicknesses across the maximum lateral dimension of the CMOS logic wafer. The prime objective of this paper is, to root cause uniformity troubleshooting by the adoption of integrated diffuser in electrochemical plating (ECP) system optimizations. These are to quantify the best degree of uniformity and high resistivity to enhance an even current distribution on the wafer. The results show that uniformity of the deposited film has been improved significantly with 1.9% i.e. maximum deviation of the deposited film thickness is at about 1.9% of the average film thickness, while standard electroplating processes typically achieves uniformity at best within 5.5% Furthermore, the origin of \"hot spots' that caused poor uniformity was identified and greatly overcome with the improved ECP system comprising an integrated diffuser design and process modifications in real troubleshooting of back end operation line (BEOL) of semiconductor foundry.", "author_names": [ "Yasmin Abdul Wahab", "Anuar Fadzil", "Norhayati Soin", "Sharifah Fatmadiana", "Zaira Zaman Chowdhury", "Nor Aliya Hamizi", "Omid Akbarzadeh Pivehzhani", "Thennarasan Sabapathy", "Y Al-Douri" ], "corpus_id": 139720077, "doc_id": "139720077", "n_citations": 5, "n_key_citations": 0, "score": 1, "title": "Uniformity improvement by integrated electrochemical plating process for CMOS logic technologies", "venue": "Journal of Manufacturing Processes", "year": 2019 }, { "abstract": "The recent improvement of VLSI process technologies enables us to integrate a large number of transistors on one chip, and significantly improves the circuit performance. On the other hand, the methodology of VLSI design becomes more and more complex and some new problems, such as Design For Manufacturability (DFM) have arisen. Due to the very high costs associated with the manufacturability of sub micron integrated circuits, even a modest yield improvement can be extremely significant. In order to achieve the high yield, a standard cell layout synthesis considering the DFM is required since standard cells are the most basic elements of the cell based design methodology as described in Chapter 1. This chapter describes a comprehensive CMOS logic cell layout synthesis technique for yield optimization by minimizing the sensitivity to wiring faults due to spot defects. Spot defect is one of the main sources of electrical failure in VLSI integrated circuits. We modeled the sensitivity to wiring faults on intra cell routings with consideration to the spot defects size distribution and the end effect of critical areas. Critical area is defined as the area in which the center of a spot defect must fall to cause a fault. We comprehensively generate the minimumwidth layouts of CMOS logic cells and the exact optimal layouts are selected from all the possible minimum width layouts by using our model of the sensitivity to wiring faults as a cost metric. Although the critical area used for the sensitivity calculation is extracted from the original layout patterns, the feasibility of the proposed sensitivity model to the practical lithography system is discussed. Moreover, the adequacy of the proposed sensitivity to the other cost metrics such as the cell delay and the total intra cell wire length is demonstrated. The impact of the sensitivity reduction on the yield is also discussed in this chapter.", "author_names": [], "corpus_id": 15746152, "doc_id": "15746152", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Yield Optimal Cell Layout Synthesis for CMOS Logic Cells", "venue": "", "year": 2011 }, { "abstract": "The realization of large area electronics with full integration of 1D thread like devices may open up a new era for ultraflexible and human adaptable electronic systems because of their potential advantages in demonstrating scalable complex circuitry by a simply integrated weaving technology. More importantly, the thread like fiber electronic devices can be achieved using a simple reel to reel process, which is strongly required for low cost and scalable manufacturing technology. Here, high performance reel processed complementary metal oxide semiconductor (CMOS) integrated circuits are reported on 1D fiber substrates by using selectively chemical doped single walled carbon nanotube (SWCNT) transistors. With the introduction of selective n type doping and a nonrelief photochemical patterning process, p and n type SWCNT transistors are successfully implemented on cylindrical fiber substrates under air ambient, enabling high performance and reliable thread like CMOS inverter circuits. In addition, it is noteworthy that the optimized reel coating process can facilitate improvement in the arrangement of SWCNTs, building uniformly well aligned SWCNT channels, and enhancement of the electrical performance of the devices. The p and n type SWCNT transistors exhibit field effect mobility of 4.03 and 2.15 cm2 V 1 s 1 respectively, with relatively narrow distribution. Moreover, the SWCNT CMOS inverter circuits demonstrate a gain of 6.76 and relatively good dynamic operation at a supply voltage of 5.0 V.", "author_names": [ "Jae Sang Heo", "Taehoon Kim", "Seok-Gyu Ban", "Daesik Kim", "Jun Ho Lee", "Jesse S Jur", "Myung-Gil Kim", "Yong-Hoon Kim", "Yongtaek Hong", "Sung Kyu Park" ], "corpus_id": 205280698, "doc_id": "205280698", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "Thread Like CMOS Logic Circuits Enabled by Reel Processed Single Walled Carbon Nanotube Transistors via Selective Doping.", "venue": "Advanced materials", "year": 2017 }, { "abstract": "This paper presents Common Mode Rejection Ratio's (CMRR) measurement results of a multichannel integrated circuit dedicated to the recording neurobiological signals and shows the design method that allows for CMRR improvement in multichannel architectures. A 64 channel Neuro Stimulation Recording chip named NRS64 is processed in CMOS 180nm technology. The measurements are followed by the detailed analysis of effects that may cause a CMRR deterioration. The simulation results of these effects are also presented and discussed. Additionally, the method improving the CMRR is presented that allows to increase both the CMRR and its uniformity from channel to channel. Furthermore, the design of a prototype multichannel integrated circuit is presented where proposed method was applied. The chip was designed in a 180nm CMOS process.", "author_names": [ "Piotr Kmon" ], "corpus_id": 16820142, "doc_id": "16820142", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "CMRR improvement for multichannel integrated recording circuits processed in submicron technologies dedicated to neurobiology experiments", "venue": "2014 Proceedings of the 21st International Conference Mixed Design of Integrated Circuits and Systems (MIXDES)", "year": 2014 }, { "abstract": "IMPROVEMENT OF A PROPAGATION DELAY MODEL FOR CMOS DIGITAL LOGIC CIRCUITS by Rodger Lawrence Stamness Propagation delay models, for CMOS Digital Circuits, provide an initial design solution for Integrated Circuits. Resources, both monetary and manpower, constrain the design process, leading to the need for a more accurate entry point further along in the design cycle. By verifying an existing propagation delay method, and its resulting delay model, calibration for any given process technology can be achieved. Literature reviews and detailed analysis of each step in the model development allow for greater understanding of each contributing parameter, and ultimately, adjustments to the model calibration result in a more accurate analytical model. An existing model was verified and improved upon using TSMC 0.18um and IBM 0.13um SPICE decks, and the resulting improvements can be used to further assist individuals needing a method and model for deriving an initial circuit design solution for integrated circuits.", "author_names": [ "Rodger Lawrence Stamness" ], "corpus_id": 53792304, "doc_id": "53792304", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Improvement of a propagation delay model for CMOS digital logic circuits", "venue": "", "year": 2010 }, { "abstract": "Single photon avalanche diode (SPAD) detector arrays generally suffer from having a low fill factor, in which the photo sensitive area of each pixel is small compared to the overall area of the pixel. This paper describes the integration of different configurations of high efficiency diffractive optical microlens arrays onto a 32 x 32 SPAD array, fabricated using a 0.35 um CMOS technology process. The characterization of SPAD arrays with integrated microlens arrays is reported over the spectral range of 500 900 nm, and a range of f numbers from f/2 to f/22. We report an average concentration factor of 15 measured for the entire SPAD array with integrated microlens array. The integrated SPAD and microlens array demonstrated a very high uniformity in overall efficiency.", "author_names": [ "Giuseppe Intermite", "Aongus Mccarthy", "Ryan E Warburton", "Ximing Ren", "Federica A Villa", "Rudi Lussana", "Andrew J Waddie", "Mohammad R Taghizadeh", "Alberto Tosi", "Franco Zappa", "Gerald S Buller" ], "corpus_id": 27218141, "doc_id": "27218141", "n_citations": 30, "n_key_citations": 0, "score": 0, "title": "Fill factor improvement of Si CMOS single photon avalanche diode detector arrays by integration of diffractive microlens arrays.", "venue": "Optics express", "year": 2015 }, { "abstract": "This paper presents performance evaluation of high k/metal gate (HK/MG) process on an industry standard 45nm low power microprocessor built on bulk substrate. CMOS devices built with HK/MG demonstrate 50% improvement in NFET and 65% improvement in PFET drive current when compared with industry standard 45nm Poly/SiON devices. No additional stress elements were used for this performance gain. The critical path circuits of this low power microprocessor built with HK/MG show dynamic performance gain over 50% at same supply voltage and 36% lower dynamic energy at same performance. Superior SRAM minimum operating voltage characteristics are achieved due to Vt variability reduction from HK/MG. Analog circuit functionality is demonstrated by a fully integrated PLL circuitry without any modification to process.", "author_names": [ "D -G Park", "Kenneth J Stein", "Klaus Schruefer", "Y M Lee", "J -P Han", "Weicong Li", "H X Yin", "Christian Pacha", "N Kim", "M Ostermayr", "Manfred Eller", "S Kim", "K Kim", "S Han", "Klaus von Arnim", "Naim Moumen", "Michael S Hatzistergos", "T J Tang", "Rainer Loesing", "Xianfeng Chen", "Daniel Jaeger", "Haoren Zhuang", "J Chen", "W Yan", "Thomas S Kanarsky", "M Chowdhury", "Jens Haetty", "Dominic Schepis", "Michael P Chudzik", "V -Y Theon", "Srikanth Samavedam", "Vijay Narayanan", "Melanie Sherony", "Richard Lindsay", "An Steegen", "Rama Divakaruni", "Mukesh Khare" ], "corpus_id": 14443311, "doc_id": "14443311", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "High k/metal gate low power bulk technology Performance evaluation of standard CMOS logic circuits, microprocessor critical path replicas, and SRAM for 45nm and beyond", "venue": "2009 International Symposium on VLSI Technology, Systems, and Applications", "year": 2009 }, { "abstract": "We present a fully integrated 7nm CMOS platform featuring a 3rd generation finFET architecture, SAQP for fin formation, and SADP for BEOL metallization. This technology reflects an improvement of 2.8X routed logic density and >40% performance over the 14nm reference technology described in [1 3] A full range of Vts is enabled on chip through a unique multi workfunction process. This enables both excellent low voltage SRAM response and highly scaled memory area simultaneously. The HD 6 T bitcell size is 0.0269um2. This 7nm technology is fully enabled by immersion lithography and advanced optical patterning techniques (like SAQP and SADP) However, the technology platform is also designed to leverage EUV insertion for specific multi patterned (MP) levels for cycle time benefit and manufacturing efficiency. A complete set of foundation and complex IP is available in this advanced CMOS platform to enable both High Performance Compute (HPC) and mobile applications.", "author_names": [ "Shreesh Narasimha", "Basanth Jagannathan", "Atsushi Ogino", "Daniel Jaeger", "Brian Greene", "C D Sheraw", "Kai Zhao", "Bala Haran", "Unoh Kwon", "A K M Mahalingam", "B Kannan", "Bradley Morganfeld", "Jessica Dechene", "Carl Radens", "A Tessier", "A Hassan", "Haritez Narisetty", "I Ahsan", "Massud A Aminpur", "Chul An", "Michael V Aquilino", "A S Arya", "Rod Augur", "N Baliga", "Ratnakar D Bhelkar", "Glenn A Biery", "Alisa Blauberg", "Natalia Borjemscaia", "Andres Bryant", "L Cao", "Vinod Chauhan", "M Chen", "L Cheng", "Jae-Ouk Choo", "Cathryn Christiansen", "T-Y Chu", "B Cohen", "R Coleman", "David Conklin", "Stephen W Crown", "Adam da Silva", "Dan J Dechene", "Garo J Derderian", "Sadanand Deshpande", "G Dilliway", "Keith Donegan", "Manfred Eller", "Y Fan", "Qiang Fang", "A Gassaria", "Robert Gauthier", "S Ghosh", "George G Gifford", "T Gordon", "M Gribelyuk", "G Han", "J -H Han", "Kichon Han", "M Hasan", "Jack M Higman", "J Holt", "L Hu", "L Huang", "C Huang", "T Hung", "Y Jin", "J B Johnson", "S Johnson", "V Joshi", "Manoj Joshi", "Patrick Justison", "Srinivas Kalaga", "T J Kim", "W V Kim", "Rishikesh Krishnan", "Bharat Krishnan", "K Anil", "Mahesh Kumar", "Jung-Woo Lee", "R Lee", "John Lemon", "San Leong Liew", "P Lindo", "M Lingalugari", "M Lipinski", "P Liu", "Jiakai Liu", "Stephen Lucarini", "W Ma", "E Maciejewski", "Sudeep Madisetti", "Arkadiusz Malinowski", "Jash Mehta", "Cai Meng", "Swarupa Mitra", "Christa Montgomery", "Hasan Nayfeh", "Tanya Nigam", "Gregory A Northrop", "K Onishi", "C Ordonio", "Merve Ozbek", "Rohit Pal", "S R Parihar", "Otis Patterson", "Eswar Ramanathan", "I Ramirez", "R Ranjan", "Jeric Sarad", "V Sardesai", "Sangameshwar R Saudari", "Carl Schiller", "B Senapati", "C Serrau", "Nilay D Shah", "Tian Shen", "H Sheng", "Joseph F Shepard", "Y C Shi", "M C Silvestre", "D Singh", "Z M Song", "John R Sporre", "Purushothaman Srinivasan", "Z Sun", "A Sutton", "Ryan Sweeney", "Keith H Tabakman", "M Tan", "Xiang-hui Wang", "E Woodard", "G Xu", "D Xu", "Truong Luan Xuan", "Y Yan", "Jingyue Yang", "Kong Boon Yeap", "M Yu", "A Zainuddin", "Jia Zeng", "K K Zhang", "M Zhao", "Y Zhong", "Rick Carter", "C-H Lin", "Stephan Grunow", "Craig Child", "M Lagus", "R Fox", "E Kaste", "Geogina Gomba", "Srikanth Samavedam", "Paul D Agnello", "Dong Kyun Sohn" ], "corpus_id": 30184585, "doc_id": "30184585", "n_citations": 32, "n_key_citations": 3, "score": 0, "title": "A 7nm CMOS technology platform for mobile and high performance compute application", "venue": "2017 IEEE International Electron Devices Meeting (IEDM)", "year": 2017 }, { "abstract": "Magnetometers based on quantum mechanical processes enable high sensitivity and long term stability without the need for re calibration, but their integration into fieldable devices remains challenging. This article presents a CMOS quantum vector field magnetometer that miniaturizes the conventional quantum sensing platforms using nitrogen vacancy (NV) centers in diamond. By integrating key components for spin control and readout, the chip performs magnetometry through optically detected magnetic resonance (ODMR) through a diamond slab attached to a custom CMOS chip. The ODMR control is highly uniform across the NV centers in the diamond, which is enabled by a CMOS generated ~2.87 GHz magnetic field with 5% inhomogeneity across a large area current driven wire array. The magnetometer chip is 1.5 mm² in size, prototyped in 65 nm bulk CMOS technology, and attached to a 300 <inline formula> <tex math notation=\"LaTeX\"\\times /tex math>/inline formula> 80 <inline formula> <tex math notation=\"LaTeX\"\\mu \\text{m}{2} /tex math>/inline formula> diamond slab. NV fluorescence is measured by CMOS integrated photodetectors. This ON chip measurement is enabled by efficient rejection of the green pump light from the red fluorescence through a CMOS integrated spectral filter based on a combination of spectrally dependent plasmonic losses and diffractive filtering in the CMOS back end of line (BEOL) This filter achieves a measured ~25 dB of green light rejection. We measure a sensitivity of 245 nT/Hz^1/2 marking a 130<inline formula> <tex math notation=\"LaTeX\"\\times /tex math>/inline formula> improvement over a previous CMOS NV sensor prototype, largely thanks to the better spectral filtering and homogeneous microwave generation over larger area.", "author_names": [ "Mohamed I Ibrahim", "Christopher Foy", "Dirk R Englund", "Ruonan Han" ], "corpus_id": 218596092, "doc_id": "218596092", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "High Scalability CMOS Quantum Magnetometer With Spin State Excitation and Detection of Diamond Color Centers", "venue": "IEEE Journal of Solid State Circuits", "year": 2021 }, { "abstract": "Schmitt triggers with standard CMOS logic circuits are described, first. Mathematical models for calculating basic parameters and their limits are presented. Most of the chapter is dedicated to different solutions for CMOS and BiCMOS Schmitt logic circuits in monolithic integrated circuits. Two types of inverters with entirely different topologies are described. Also, solutions for Schmitt triggers with voltage controlled thresholds are described. Beside inverters, NAND and NOR Schmitt logic circuits are analyzed. Basic circuit is inverted Schmitt trigger with three pairs of CMOS transistors. Expansion of the number of inputs is reached in a similar way as in standard CMOS and BiCMOS logic circuits. It is shown that voltage transfer characteristics depend, beside voltage supply and parameters of transistors, on the number of logical circuits' inputs. NAND and NOR Schmitt circuits, in which voltage hysteresis in transfer characteristic is generated only through one input, are also described. Analytic models and SPICE simulations are used for analysis of static and dynamic parameters and conditions for work stability and reliability. Areas of reliability, influence of technology and electrical parameters of transistors and their limits are analyzed. Concerning the field of application, in literature there are different solutions of Schmitt triggers (Zou et al, 2008, Al Sarrawi, 2008, Katyal et al, 2008, Lo et al, 2010) In this chapter, solutions with fundamental applications in digital integrated circuits Schmitt logic circuits are described. The author published most of these solutions (Dokic, 1983, Dokic 1984, Dokic 1996, Dokic, 1988) Today, some of them (Dokic, 1984) are treated as conventional. The term regenerative is used because every change of state is followed by a regenerative process positive feedback. Owning to that, transfer characteristic has shape of a hysteresis, like in Schmitt trigger. That is why the term Schmitt logic circuits is most commonly used. Unlike conventional logic circuits, where the output level is uniformly determined for the input voltage value, for Schmitt logic circuits, in certain extent, it is not uniformly determined. In fact, due to hysteresis, in the area of the input voltages between two logic thresholds, logic state at the output depends, beside the input voltage value, also on the previous state. Due to that Schmitt circuits can be used as filters for low frequency interferences. An example of this kind of application is given in Fig.1. Whenever the value of the input signal passes the value of the threshold voltage Ji Zhang of the standard logic circuit, a change of the logic state at the output appears. Therefore, the changes of the input voltage created by noise are transferred to the output as glitches. The change of the logic state at the output of the Schmitt logic circuit can appear only after the noise amplitude of which is greater than the voltage hysteresis.", "author_names": [ "Branko Dokic" ], "corpus_id": 512393, "doc_id": "512393", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "CMOS and BiCMOS Regenerative Logic Circuits", "venue": "", "year": 2012 } ]

[ { "abstract": "We report on a novel electron paramagnetic resonance (EPR) technique that merges electrically detected magnetic resonance (EDMR) with a conventional semiconductor wafer probing station. This union, which we refer to as wafer level EDMR (WL EDMR) allows EDMR measurements to be performed on an unaltered, fully processed semiconductor wafer. Our measurements replace the conventional EPR microwave cavity or resonator with a very small non resonant near field microwave probe. Bipolar amplification effect, spin dependent charge pumping, and spatially resolved EDMR are demonstrated on various planar 4H silicon carbide metal oxide semiconductor field effect transistor (4H SiC MOSFET) structures. 4H SiC is a wide bandgap semiconductor and the leading polytype for high temperature and high power MOSFET applications. These measurements are made via both \"rapid scan\" frequency swept EDMR and \"slow scan\" frequency swept EDMR. The elimination of the resonance cavity and incorporation with a wafer probing station greatly simplifies the EDMR detection scheme and offers promise for widespread EDMR adoption in semiconductor reliability laboratories.", "author_names": [ "Duane J McCrory", "Mark Anders", "Jason T Ryan", "Pragya R Shrestha", "Kin P Cheung", "Patrick M Lenahan", "Jason P Campbell" ], "corpus_id": 73414583, "doc_id": "73414583", "n_citations": 4, "n_key_citations": 0, "score": 1, "title": "Slow and rapid scan frequency swept electrically detected magnetic resonance of MOSFETs with a non resonant microwave probe within a semiconductor wafer probing station.", "venue": "The Review of scientific instruments", "year": 2019 }, { "abstract": "We present a rotary stage microwave probe station suitable for magnetic films and spintronic devices. Two stages, one for field rotation from parallel to perpendicular to the sample plane (out of plane) and the other intended for field rotation within the sample plane (in plane) have been designed. The sample probes and micro positioners are rotated simultaneously with the stages, which allows the field orientation to cover th from 0( to 90( and ph from 0( to 360( th and ph being the angle between the direction of current flow and field in a out of plane and an in plane rotation, respectively. The operation frequency is up to 40 GHz and the magnetic field up to 1 T. The sample holder vision system and probe assembly are compactly designed for the probes to land on a wafer with diameter up to 3 cm. Using homemade multi pin probes and commercially available high frequency probes, several applications including 4 probe DC measurements, the determination of domain wall velocity, and spin transfer torque ferromagnetic resonance are demonstrated.", "author_names": [ "Shikun He", "Zhaoliang Meng", "Lisen Huang", "Lee Koon Yap", "Tiejun Zhou", "Christos Panagopoulos" ], "corpus_id": 12917517, "doc_id": "12917517", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "A versatile rotary stage high frequency probe station for studying magnetic films and devices.", "venue": "The Review of scientific instruments", "year": 2016 }, { "abstract": "With a growing effort in research and development of an alternative material to bulk Nb for a superconducting radiofrequency (SRF) cavity, it is important to have a cost effective method to benchmark new materials of choice. At Old Dominion University's Center for Accelerator Science, a cryogenic probe station (CPS) will be used to measure the response of superconductor samples under RF fields. The setup consists of a closed cycle refrigerator for cooling a sample wafer to the cryogenic temperature, a superconducting magnet providing a field parallel to the sample, and DC probes in addition to RF probes. The RF probes will extract a quality factor from a sample patterned in a coplanar waveguide resonator structure on a 2in wafer. From the measured quality factor, the surface resistance and the penetration depth as a function of temperature and magnetic field will be calculated. This paper will discuss the design and measurement procedures of the current CPS setup.", "author_names": [ "Junki Makita", "Jean Roger Delayen", "Alexander V Gurevich", "Gianluigi Ciovati" ], "corpus_id": 210884041, "doc_id": "210884041", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "CRYOGENIC PROBE STATION AT OLD DOMINION UNIVERSITY CENTER FOR ACCELERATOR SCIENCE*", "venue": "", "year": 2018 }, { "abstract": "The biaxial magnetic field setup for angular dependent measurements of magnetic thin films and spintronic nanodevices is designed and presented. The setup allows for the application of the in plane magnetic field using a quadrupole electromagnet, controlled by power supply units and integrated with an electromagnet biaxial magnetic field sensor. The setup may be used in a wide range of experiments, where the application of precise in plane magnetic field is needed. In our experiment, the probe station is equipped with a microwave circuitry, which enables angle resolved spin torque measurements. The angular dependences of magnetoresistance and spin diode effect in a multilayer patterned into \\mu \\text{m} scale strips are shown as an operational verification of the experimental setup. We adapted an analytical macrospin model to reproduce both the resistance and spin diode angular dependence measurements.", "author_names": [ "Piotr Rzeszut", "Witold Skowronski", "Slawomir Zietek", "Piotr Ogrodnik", "Tomasz Stobiecki" ], "corpus_id": 49891387, "doc_id": "49891387", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Biaxial Magnetic Field Setup for Angular Dependent Measurements of Magnetic Thin Films and Spintronic Nanodevices", "venue": "IEEE Transactions on Magnetics", "year": 2018 }, { "abstract": "A conduction cooled cryostat has been developed for NbTi superconducting magnet used in a cryogenic probe station. In a cryogenic probe station, a sample stage for transient measurement is located in the bore of a low temperature superconducting (LTS) magnet and thermally connected to the second stage cold head of a cryocooler to cool the sample down to the liquid helium temperature. Two separate structures exist in order to maintain isolation between the LTS magnet and sample stage. The system is cooled by a two stage cryocooler, and the LTS magnet is charged and generates the designed magnetic field. When the magnet is charged and maintains a certain magnetic field, the temperature of sample stage is varied depending on the amount of heating. The thermal linkage between the LTS magnet and second stage cold head as well as the sample stage and second stage cold head is investigated in terms of the stability of LTS magnet, magnetic field, and temperature of sample stage. The mechanical module including the thermal link to control the sample stage is integrated into the system and the results of the performance test are reported.", "author_names": [ "Myung Su Kim", "Seungyung Park", "Yeon Suk Choi" ], "corpus_id": 40224637, "doc_id": "40224637", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Development of Conduction Cooled Cryostat for Superconducting Probe Station", "venue": "IEEE Transactions on Applied Superconductivity", "year": 2017 }, { "abstract": "Permanent magnets are one of the basic components of magnetic passive suspension system using superconductors. Generating magnetic field neodymium magnets are placed along the system's guide. Presented experimental studies were conducted to measure the intensity of the magnetic field, generated by a single neodymium magnet. The Brockhaus Measurements magnetic field gauge BGM 101 was used to build the measuring station. The mechanical part was based on the D4128R110 stepper motor and the ATmega2560 microcontroller, which controlled the Motor Shield module containing L293D. Configuration of proposed measuring station allows to move the gaussmeter probe horizontally, above the magnet. The controllable speed of measurement table enables to obtain accurate and reproducible magnetic field measurements.", "author_names": [ "Edyta Ladyzynska-Kozdras", "Anna Sibilska-Mroziewicz", "Slawomir Czubaj" ], "corpus_id": 117500283, "doc_id": "117500283", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Experimental Measurement of Magnetic Field Generated by Neodymium Magnet", "venue": "", "year": 2017 }, { "abstract": "A state of the art ellipsometer for user operations is being implemented at ELI Beamlines in Prague, Czech Republic. It combines three of the most promising and exotic forms of ellipsometry: VUV, pump probe and magneto optical ellipsometry. This new ellipsometer covers a spectral operational range from the NIR up to the VUV, with high through put between 1 and 40 eV. The ellipsometer also allows measurements of magneto optical spectra with a 1 kHz switchable magnetic field of up to 1.5 T across the sample combining ellipsometry and Kerr spectroscopy measurements in an unprecedented spectral range. This form of generalized ellipsometry enables users to address diagonal and off diagonal components of the dielectric tensor within one measurement. Pump probe measurements enable users to study the dynamic behaviour of the dielectric tensor in order to resolve the time domain phenomena in the femto to 100 ns range.", "author_names": [ "Shirly Espinoza", "G Neuber", "Christopher D Brooks", "Bastian Besner", "Maryam Hashemi", "Michael Rubhausen", "Jakob Andreasson" ], "corpus_id": 136342362, "doc_id": "136342362", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "User oriented end station on VUV pump probe magneto optical ellipsometry at ELI beamlines", "venue": "", "year": 2017 }, { "abstract": "We report on a novel semiconductor reliability technique that incorporates an electrically detected magnetic resonance (EDMR) spectrometer within a conventional semiconductor wafer probing station. EDMR is an ultrasensitive electron paramagnetic resonance technique with the capability to provide detailed physical and chemical information about reliability limiting defects in semiconductor devices. EDMR measurements have generally required a complex apparatus, not typically found in solid state electronics laboratories. The union of a semiconductor probing station with EDMR allows powerful analytical measurements to be performed within individual devices at the wafer level. Our novel approach replaces the standard magnetic resonance microwave cavity or resonator with a small non resonant near field microwave probe. Using this new approach we have demonstrated bipolar amplification effect and spin dependent charge pumping in various SiC based MOSFET structures. Although our studies have been limited to SiC based devices, the approach will be widely applicable to other types of MOSFETs, bipolar junction transistors, and various memory devices. The replacement of the resonance cavity with the very small non resonant microwave probe greatly simplifies the EDMR detection scheme and allows for the incorporation of this powerful tool with a wafer probing station. We believe this scheme offers great promise for widespread utilization of EDMR in semiconductor reliability laboratories.", "author_names": [ "Duane J McCrory", "Mark Anders", "Jason T Ryan", "Pragya R Shrestha", "Kin P Cheung", "Patrick M Lenahan", "Jason P Campbell" ], "corpus_id": 46971171, "doc_id": "46971171", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Wafer Level Electrically Detected Magnetic Resonance: Magnetic Resonance in a Probing Station", "venue": "IEEE Transactions on Device and Materials Reliability", "year": 2018 }, { "abstract": "Simulation studies established that the main (core) crustal and electrojet components of the Earth's magnetic field can be observed with greater resolution or over a longer time base than is presently possible by using the capabilities provided by the space station. Two systems are studied. The first, a large lifetime, magnetic monitor would observe the main field and its time variation. The second, a remotely piloted, magnetic probe would observe the crustal field at low altitude and the electrojet field in situ. The system design and the scientific performance of these systems is assessed. The advantages of the space station are reviewed.", "author_names": [ "William J Webster", "James J Frawley", "Milan Stefanik" ], "corpus_id": 129269525, "doc_id": "129269525", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Observations of the Earth's magnetic field from the Space Station: Measurement at high and extremely low altitude using Space Station controlled free flyers", "venue": "", "year": 1984 }, { "abstract": "We report on a novel semiconductor reliability technique that merges electrically detected magnetic resonance (EDMR) with a conventional semiconductor wafer probing station. This union with a semiconductor probing station allows EDMR measurements to be performed at the wafer level. Our measurements forgo a microwave cavity or resonator for a very small non resonant near field microwave probe [1] Bipolar amplification effect (BAE) [4] and spin dependent charge pumping (SDCP) [5] were demonstrated on various SiC MOSFET structures. These measurements were made via frequency swept EDMR. The elimination of the resonance cavity, and incorporation with a wafer probing station, greatly simplifies the EDMR detection scheme and offers promise for widespread EDMR adoption in semiconductor reliability laboratories.", "author_names": [ "Duane J McCrory", "Mark Anders", "Jason T Ryan", "Pragya R Shrestha", "Jason P Campbell", "Patrick M Lenahan", "Kin P Cheung" ], "corpus_id": 46895686, "doc_id": "46895686", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Wafer level EDMR: Magnetic resonance in a probing station", "venue": "2017 IEEE International Integrated Reliability Workshop (IIRW)", "year": 2017 } ]

[ { "abstract": "", "author_names": [ "Louis E Brus" ], "corpus_id": 96550419, "doc_id": "96550419", "n_citations": 2220, "n_key_citations": 10, "score": 1, "title": "Electronic wave functions in semiconductor clusters: experiment and theory", "venue": "", "year": 1986 }, { "abstract": "", "author_names": [ "Louis E Brus" ], "corpus_id": 197152092, "doc_id": "197152092", "n_citations": 241, "n_key_citations": 15, "score": 0, "title": "Electronic Wave Functions in semiconductor Clusters: Experiment and Theory", "venue": "", "year": 1986 }, { "abstract": "TiO2 is an active semiconductor used in photocatalysis, solar cells devices and energy storage applications. For this reason, recent efforts are aimed to design and modify the properties of this semiconductor. In the present work we calculate theoretically the lowest energy structures of TiO2, and The Density of States (DOS using Molecular Dynamics and DFT respectively. Such geometries were compared with those reported experimentally, and their atomic structures were constructed with planes (1 0 1) of anatase symmetry. The nanoparticles considered were (TiO2)n with n=18, 28, and 38. The aim of this work is to correlate the size dependence of TiO2 nanoparticles with temperature effects on anatasa simmetry. A quenching process was used in order to reproduce the temperature conditions found at experiment. Also, The RDFs (Radial Distribution Function) of these materials were obtained. The DOS were determined using Density Functional Theory (DFT) calculations, it was implemented with FHI AIMS software package [1,2] and Molecular Dynamics using DL POLY[3] and REAXFF software packages [4,5] The DFT calculations were performed using a plane wave basis set, and the generalized gradient approximation (GGA) of Perdew Burke Ernzerhof for the exchange correlation energy [6] The core electrons were described with Projector Augmented Wave (PWA) method. Moreover, relativistic scalars effects (ZORA)[7] and Van Der Waals interactions were considered using Tkatchenko Scheffler methodology[8]", "author_names": [ "Tania G Diaz Rodriguez", "G Gonzalez", "H Santiesteban Juarez", "Mauricio Pacio", "Jesus Muniz" ], "corpus_id": 104422773, "doc_id": "104422773", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Theoretical study of the electronic structure and stability of titanium dioxide clusters (TiO2) n with n 18, 28 and 38", "venue": "", "year": 2018 }, { "abstract": "Sakoharaet al. \"Visible Luminescence and Surface Proper ties of Nanosized ZnO Colloids Prepared by Hydrolyzing Zinc Acetate\" J. Phys. Chem B. vol. 102, No. 50, Dec. 1998, pp. 1016910175. Hilgendorff et al. \"From ZnO Colloids to Nanocrystalline Highly Conductive Films\" J. Electrochem. Soc. vol. 145, No. 10, Oct. 1998, pp. 3632 3637. Spanhel et al. \"Semiconductor Clusters in the Sol Gel Process: Quantized Aggregation, Gelation, and Crystal Growth in Concentrated ZnO Colloids' J. Am. Chem. Soc. 1991 (month unavailable) 113, pp. 2826 2833. Patent Abstracts of Japan, vol. 199, No. 605, corresponding to Jp 08 026823 A (Toshio Tsuchiya) Jan. 30, 1996. J. Phys. Chem. 92 (month unavailable) 1988, Month unknown pp. 482 487, \"Photochemistry and Radiation Chemistry of Colloidal Semiconductors. 23. Electron Stor age on ZnO Particles and Size Quantization\" Markus Haase, Horst Weller and Arnim Henglein. J. Phys. Chem. 90 (month unavailable) 1986, Month unknown pp. 2555 2560, \"Electronic Wave Functions in Semiconductor Clusters: Experiment and Theory\" Louis Brus. Gmelins Handbuch, Vol 32, 8\" ed. Supplementary vol. (month unavailable) 1956, Month unknown pp. 722 773 \"Zinkoxyd\"", "author_names": [ "Markus Haase", "Arnim Henglein", "Gary Matz" ], "corpus_id": 88509073, "doc_id": "88509073", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "ZINC OXDE GELS", "venue": "", "year": 2017 }, { "abstract": "In this paper we report the study of the change in electrical properties of zigzag carbon nanotubes (10, 0) under uniaxial compressive and tensile deformation using Density Functional Theory (DFT) calculation. There is an energy gap of 0.972 eV between occupied and unoccupied region in the optimized structure calculation. We found that the band gap of the semi conducting zigzag (10, 0) CNTs decreases as the strain increases for both compressive and tensile deformation. Different profiles of charge density appear for tensile and compressive deformations. The charge density of compressed state is more localized in the z direction of C C bonds. Meanwhile, charge density of elongated state is localized in the diagonal C C bonds direction. At the large tensile strain, the C C bonds break at the z direction C C bonds. ICOHP analysis shows that the bond strength of CNT drastically decreases under tensile deformation. Keyword: band gap, carbon nanotubes, charge density, density functional theory. INTRODUCTION The development of science and technology has evolved into the era of nanotechnology. Among the many nanostructured materials, carbon nanotubes (CNTs) have attracted considerable attention. Compared to other nanoscale materials, single walled carbon nanotubes (SWCNT) possess particularly outstanding physical and electronic properties. Due to the extremely small size of CNTs, the evaluation of its mechanical properties, such as elastic modulus and tensile/compressive strength presents significant challenges to researchers who work in nanomechanics. Electronic states of single walled carbon nanotubes (SWNCT) such as Density of states (DOS) and band gap, could be correlated with their finite mechanical deformation behavior. The study of this effect is important in view of the ability to manipulate individual nanotubes for many applications. Recently, Obitayo and Liu [1] have been developed carbon nanotubes as strain sensor its I V characteristic behavior due to axial change has been explored. In that work, they conclude that for carbon nanotube based strain sensing applications, the small gap semiconducting single walled carbon nanotubes offer the greatest sensitivity. Even though many research have studied the change of electronics properties of nanotubes under uniaxial deformation [1 3] the theoretical approach in investigating the band gap changes has not been revealed up completely. Because of the nanoscale size of CNTs, the experiments to measure the properties of individual CNT are quite difficult. Therefore, the ab initio calculations have been regarded as a powerful tool to study properties of CNTs. In the present report, we calculate the atomic and electronic structure changes of the CNTs under tensile and compressive deformation by using Density Functional Theory (DFT) calculation. We focused on band gap and bond strength changes due to mechanical uniaxial tensile and compressive deformation. COMPUTATIONAL DETAILS We carried out the first principles calculations on the density functional theory (DFT) level, using the \"Vienna ab initio simulation package\" [4 6] The calculation was performed in QC Cluster at Department of Physics ITB. Generalized gradient approximation (GGA) with the Perdew Burke Ernzerhof (PBE) [7] functional is selected in our calculations. A plane wave basis set was employed within the framework of the projector augmented wave method.[8, 9] K points (1 x 1 x 17 Monkhorst Pack grid) were used in this simulations. One k point in the two perpendicular directions was enough because the distance between the individual tubes was chosen very large (16 A) so that the interaction between them was negligible. We selected zigzag type semiconducting CNTs (10,0) The axial direction (z) of these CNTs was selected as the tensile direction. Before we started the tensile test, the z dimension of the supercells and the initial atomic configuration were completely relaxed. These relaxed z dimensions of the supercells were used as a reference when calculating the applied strains in the following discussion. The electronic properties of zigzag CNT can be obtained by using electronic density of states calculations. The optimized structure data from SCF calculations can be used to reduce calculation time and neglect structural optimization process. Generally, the mesh K point sampling for DOS calculation is higher than that of SCF calculations for calculation's accuracy. To know further the nature of bonding of elongated /compressed CNT, we projected plane waves to local orbital basis functions to extract the crystal orbital Hamilton population COHP) [10] The integration of COHP for all energies up to EF gives integrated COHP (ICOHP) to render a quasiquantitative interpretation [11] of the net bonding characteristics. This ICOHP were calculated by using the program Local Orbital Basis Suite towards Electronic Structure Reconstruction (LOBSTER) [11 13] VOL. 13, NO. 7, APRIL 2018 ISSN 1819 6608 ARPN Journal of Engineering and Applied Sciences (c)2006 2018 Asian Research Publishing Network (ARPN) All rights reserved. www.arpnjournals.com 2391 RESULT AND DISCUSSIONS Change in density of states during deformation From the DFT calculation using VASP software, we got the optimized structure of zigzag CNTs (10, 0) The zigzag edge (10, 0) CNT has two different carboncarbon (C C) bond length, 1.42 A and 1.43 A. The diameter of this optimize structure is 7.89 A. Our optimized CNTs model was then be compressed and elongated in uniaxial direction (z direction) There is an energy gap of 0.972 eV between occupied and unoccupied region, which indicates that the system is semiconducting. This result is in agreement with other first principle calculation studies which have been published [14 16] This result is also supported by experimental and theoretical approach results from other studies. According to the chiral vector information, the pristine zigzag edge (10,0) CNT is semiconducting material [17] This result is also in a good agreement with experimental result by using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) [17, 18] The electronic structures of CNTs with various structures under axial strain are evaluated by DFT calculations. To analyze the band gap dependency on uniaxial deformation, we observe the DOS of the deform structure of zigzag edge CNT (10, 0) The band gap versus strain curves for a zigzag (10, 0) CNTs during the tensile tests are shown in Figure 1. Negative value means that the final deformed structure is shorter than the optimize bulk structure (compressed) Vice versa, the positive value shows that the final deformed structure is longer than the optimize bulk structure (elongated) Previous work on semiconducting CNTs shows the same result with this work. The band gap for the semiconducting zigzag (10, 0) CNTs displays some variation upon deformation, but most of it decreases as the strain increases [16] This calculation result also shows that there is semiconductor metallic transition of the CNTs. The (10,0) zigzag tube has zero band gap like graphene at the strain of 8.3% which means that it possesses metallic electronic properties at this state and returns to the semiconducting state as the strain increases. Since another work suggests that the small gap semiconducting single walled carbon nanotubes offer the greatest sensitivity for the sensor application, we can conclude that CNT (10, 0) can be a good candidate for CNT based strain sensors. Figure 1. The band gap versus strain for semi conducting zigzag (10,0) CNTs. Deformation electron density VOL. 13, NO. 7, APRIL 2018 ISSN 1819 6608 ARPN Journal of Engineering and Applied Sciences (c)2006 2018 Asian Research Publishing Network (ARPN) All rights reserved. www.arpnjournals.com 2392 Figure 2. (a) Focused area for charge density analyzing; Charge density of the (10,0) zigzag CNT under: (b) 2% (c) 10% compressive and (e) 1% (f) 10% tensile strain. Figure 2 shows change in the charge density of the (10,0) zigzag CNT under compressive and tensile strain. We analyze the two dimensional charge density slice of the semiconducting zigzag (10, 0) CNTs focusing on the red circle area shown in the Figure 2(a) Charge density of the CNT before imposed by uniform stretching or compressed of the initial atomic configuration in the z direction is shown in Figure 2(b) Charge density during the compressive deformation is shown in Figure 2(c) and (d) it can be seen that the charge density becomes more localized in the z direction C C bonds and the angle of the hexagonal carbon formation decreases. The amount of localized charge density also increases as the compressive strain increase. The different profile appears during tensile deformation. The charge density, as shown in Figure 2(e) and (f) decreases as the tensile strain increase. The Charge density is localized in the diagonal C C bonds. At large strain, i.e. 7% for tensile and 5% for compression, the C C bonds break at the z direction C C bonds. This indicates that for more than 7% tensile and 5% compressive strain, CNT starts to break and no longer efficient to be used as a sensor. Because when some C C bonds are broken, the CNT is in plastic region, so when it is strained, it will not return to its original shape. For the strain sensor application, CNT should be able to return to its original shape, it means that the CNT should be in the elastic region. From our charge density analysis, the elastic region of CNT (10, 0) might be below 7% tensile and 5% compressive strain. From this figure also we can conclude that the bond strength of the CNT under compressive deformation is higher compared to that of tensile deformation. It is indicated by the higher value of the electron density in compressive deformation compared to tensile deformation at the same strain. To study further about this bond strength, we perform the ICOHP calculation. Bond strength Integratin", "author_names": [ "Irfan Dwi Aditya", "" ], "corpus_id": 189859481, "doc_id": "189859481", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "ELECTRONIC PROPERTIES OF SEMICONDUCTING ZIGZAG 10 0 CARBON NANOTUBES DUE TO UNIAXIAL STRAIN", "venue": "", "year": 2018 }, { "abstract": "Recent theoretical studies on the origin of the pseudogap emerging in underdoped cuprate superconductors are overviewed, based on insights obtained by a cluster extension of the dynamical mean field theory (cDMFT) for the doped two dimensional (2D) Mott insulator. The pseudogap obtained in the cDMFT shows an s wave like full gap structure, distinct from the d wave superconducting gap. The zero temperature electronic structure supports that a non Fermi liquid phase exists and underlies the pseudogap. The non Fermi liquid phase is separated from the larger doped Fermi liquid by topological transitions of the Fermi surface and an emergence of zeros of Green's function. A coexisting evolution of the poles (Fermi surface) and zeros of the Green's function is a unique feature of the pseudogap phase. The spectra well reproduce the arc/pocket formation, together with basic experimental properties of the pseudogap phase in the cuprates. Furthermore, a full gap structure is supported by a comparison with the results of Raman experiments. The overall feature supports the proximity of the Mott insulator and the significance of the quantum criticality of the Mott transition. These numerical results are further favorably interpreted by extending the exciton concept, known in semiconductors, to doped Mott insulators. In this composite fermion (CF) theory, the pseudogap emerges as a gap arising from a hybridization of the quasiparticle (QP) with the CF. The pairing channel opening between a QP and a CF solves the puzzle of the dichotomy between the d wave superconductivity and the precursory insulating gap in the same antinodal region. A mechanism of superconductivity emerges from this pairing.", "author_names": [ "Masatoshi Imada", "Shiro Sakai", "Youhei Yamaji", "Yukitoshi Motome" ], "corpus_id": 122538914, "doc_id": "122538914", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Theory of pseudogap in underdoped cuprates", "venue": "", "year": 2013 }, { "abstract": "A chromophore is a molecule that appears colorful to the human eye in sunlight. The recognized color is related to the wavelength of light, or in face of particle wave dualism, to the energy of photons absorbed by the molecule. Light absorption, also called photo excitation, corresponds to a transition of the molecule from its ground state to an electronically excited state. The energy gained during excitation allows the molecule to undergo manifold chemical and physical processes, giving rise to the presents of a plethora of chromophores in nature and technology. In order to rationalize these light induced processes, the involved electronic ground and excited states of a molecule can be investigated by means of quantum chemical methods. These allow to determine the energy and properties of the molecule in its different electronic states. An important step in the interpretation of the results of such calculations is to determine the character of an excited state, which is directly connected with many properties, such as the interaction with an environment, reaction pathways and deexcitation processes. The aim of this work is to develop new tools for the investigation of excited states, their characters, and quantum chemical methods for their description. The central idea is to rationalize excited states in terms of correlated electron hole quasiparticles, i.e. excitons, a concept from solid state physics. The working hypothesis is to identify the one particle transition density matrix (1TDM) as an effective electron hole (i.e. exciton) wave function. The character of an excited state can in turn be determined from the calculated exciton properties. These properties are computed by evaluating expectation values of the exciton wave function with respect to operators of interest. In practice, several protocols have been developed, which characterize spatial and statistical properties of the electron hole quasiparticle. These excited state descriptors are directly comparable to results from solid state physics as well as from experiments, emphasizing their physical significance. In contrast to standard approaches, deriving excited state characters from exciton properties has some immediate advantages. Different types of excited states such as charge transfer, Rydberg or local, can be directly determined according to a few exciton descriptors. The use of quantitative descriptors is comparably unbiased, since it does not rely on an ambiguous visual interpretation of molecular orbitals (MOs) involved in the electronic transition. Moreover, exciton descriptors allow to investigate excited states that are poorly represented in the MO picture. Since exciton analysis is based on the 1TDM, which is a method independent quantity, the descriptors allow to investigate quantitative differences between the descriptions of excited states at various levels of theory. The presented approach is particularly relevant for molecules featuring excited states with exciton character. A particularly important substance class are large p conjugated organic molecules. Here, delocalized p electrons play a decisive role and require precise description of correlation effects, posing a challenge for quantum chemical methods. The scientific interest in large p conjugated organic molecules is triggered by their special electronic properties, which are applied in organic electronics. In the course of this work, a variety of excited states of extended p conjugated organic molecules is calculated by means of correlated ab initio methods as well as by time dependent density functional theory (TDDFT) and subjected to exciton analysis. In Chapter 3, exciton sizes are investigated for excited states of poly(para phenylene vinylene) (PPV) oligomers and polyacenes. Excited states are found to differ in exciton sizes depending on irreducible representations and multiplicities. In Chapter 4, PPV is thoroughly investigated as a prototypical organic semiconductor to rationalize its exciton properties from a quantum chemical perspective. The emergence of excitonic states is examined for a series of PPV oligomers with different chain length. It is found that exciton formation takes place for oligomers with four or more building blocks. To gain insight into the spectroscopic properties of the PPV polymer, the largest still computationally feasible representative, the octamer (PV)7P is studied intensely. A systematic analysis of forty excited states allows to examine their exciton characters in detail. The investigated excitons are found to have well defined structures that can be rationalized in terms of Frenkel and Wannier exciton models. The results are in good agreement with experimental findings and band structure calculations of PPV. To investigate the effects of exciton formation for a more chemically diverse set of molecules, a variety of aromats as well as heteroaromats are investigated in Chapter 6. It is found that the first excited state of these p systems has a uniform exciton character with an exciton size converging towards 7 A very similar to the trends in PPV. The explicit chemical structures and presence of heteroatoms have surprisingly little influence on this character. Shifting the focus to methodological aspects, Chapter 6 reveals the influence of exchange correlation (xc) functionals on the description of exciton properties in TDDFT. By comparing exciton sizes and electron hole correlation coefficients, it is found that there are major differences in the excited state description for the tested xc functionals. The trends amongst different xc functionals suggest that these deviations are mostly governed by the amount of nonlocal orbital exchange (NLX) in the xc functionals. This finding is of great significance showing that a single parameter can induce a complete change in the electron hole interaction from repelling (anti correlated) to strongly attractive (correlated) A more general investigation of the same effect is presented for Tozer's benchmark set in Chapter 5. This set is composed of a broad selection of molecules featuring different types of excited states and designed to develop diagnostic tools for TDDFT. It is well known that excited states which involve nonlocal electron transitions, such as charge transfer, Rydberg or p p* states of extended p systems, show systematic errors in excitation energy for different types of xc functionals. Here, exciton descriptors reveal that these errors are related to substantial differences in the description of the respective excited states by the xc functionals. Since exciton descriptors are able to identify all problematic cases, they are suggested as diagnostic tools for TDDFT. Ultimately, Chapter 7 focuses on the evaluation of excited state methods. For this purpose, the selection of methods is extended to include also equation of motion coupled cluster singles doubles (EOM CCSD) and a diverse set of applications is investigated. Exciton properties calculated with correlated ab initio methods (ADC(2) ADC(3) and EOM CCSD) as well as TDDFT are compared, revealing strengths and weaknesses of the methods in different applications. The most important outcome of investigating exciton properties is that accuracy in terms of excitation energies is not necessary a measure for the quality of description of the underlying wave function and properties of a system. In fact, the best agreement in terms of exciton properties with respect to high level ab initio data is obtained with an xc functional that is the least accurate in terms of excitation energies for several examples. The presented approach is publically available as open source code package libwfa and integrated in the Q Chem program package.", "author_names": [ "Stefanie A Mewes" ], "corpus_id": 105116300, "doc_id": "105116300", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Exciton analysis tools for quantum chemical investigation of molecular photochemistry", "venue": "", "year": 2018 }, { "abstract": "Abstract We derive a theory of magnetization for the diluted magnetic semiconductor, p type Sn1 xGdxTe including the contributions from Gd3+ local moments, carrier local moment hybridization and lattice diamagnetism as a function of temperature and magnetic field. The local moment contribution Mlocal is a sum of three contributions: Mlocal=Ms+Mp+Mt, where Ms is the dominant single spin contribution, and Mp and Mt are the contributions from clusters of two and three spins, respectively. We have also calculated the contribution due to spin polarized holes for carrier densities of order 1020 cm 3, using a k p model, where p is the momentum operator in the presence of the spin orbit interaction and k is the hole wave vector. This contribution includes the carrier local moment hybridization. We have also included a diamagnetic lattice contribution, which comes from inter band orbital and spin orbit contributions. In this contribution, the symbol k is used for the electronic wave vector. The local moment contribution is dominant and primarily comes from the isolated spins. However, the two and three spin contributions increase with increase in the magnetic impurity concentration. The magnitude of the hole spin polarization is about two orders less than the local moment contribution even at field strength of 25 T. However, the magnetization due to carrier spin density has intrinsic importance due to its role in possible spintronics applications. The lattice diamagnetism shows considerable anisotropy. The total magnetization is calculated from all the three contributions Mlocal, Mc (due to carriers, here holes) and Mdia. We have compared our results with experiment wherever available and the agreement is fairly good.", "author_names": [ "Kalachand Dash", "Gouri S Tripathi" ], "corpus_id": 120145889, "doc_id": "120145889", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Theory of magnetization of p type Sn1 xGdxTe: Contributions from local moments, lattice diamagnetism and carriers", "venue": "", "year": 2012 }, { "abstract": "Fundamental Theory. Density Functional Theory and Local Potential Approximations from Momentum Space Considerations. Aspects of Density Functional Theory. On the Calculation of Potentials from Densities. The Chemical Potential for Interacting Fermions in a Harmonic Potential. Density, Total Energy and Chemical Potential of Atomic Ions and some Molecules. Some Aspects of the Role of Single Particle Density in Chemistry. The Mechanics of and an Equation for the Electronic Charge Density. The Qualitative Theory of the Current Density in Molecules. The Constrained Search Approach, Mappings to External Potentials, and Virial Like Theorems for Electron Density and One Matrix Energy Functional Theories. Self Interaction Correction. Some Approaches to Density Functional Theory. Exchange Correlation Energy Functionals in the Density Functional Formalism. An Approach to Electron Correlation beyond the Local Spin Density Approximation. Pair Correlation Energies and Local Spin Density Functionals. On the Extension of the Statistical Energy Expression to Multi Determinantal Wave Functions. The Weizsacker Term, its Corrections and Virial Partitioning in Density Functional Theory. The Second Order Reduced Density Matrix and the Chemimal Bond. Characteristic Function Approach to Density Matrix Calculations. On the Systematic Assessment of Correlation Effects in Local Density Models. Relativistic Density Functional Theory. A Phase Space Approach to Energy Densities in Position Space. Applications. Application of the Hartree Fock Slater Method in Photoelectron Spectroscopy. SCF X? SW Cluster Molecular Orbital Models of Catalysts, Alloys, Magnetic Materials, and Superconductors. Some Applications of the Density Functional Formalism to Chemisorption. Density Functional Calculations for Atomic Clusters. Cohesive Energy, Spectroscopic, and Magnetic Properties of Small Clusters. Calculations of Hyperfine Interactions in Transition Metal Compounds in the Local Density Approximation. Local Density Approach to Surfaces and Adsorbed Layers. Electron Densities in Solid Compounds. Local Density Approximations for Relativistic Exchange Energies. Relativistic Multiple Scattering X? Calculations. Dirac Scattered Wave Calculations. Theoretical Valence Charge Densities for Graphite, Diamond and LiC6. Dependence of the Self Consistent One Electron Density of Anisotropic Semiconductors on Local Density Approximations. Ray Bragg and Compton Scattering Experiments Used as Tests of the Validity of the Local Density Approximation. Multipole Expansion as an Alternative Representation of Charge Density. Measured Electron Density Distributions in Crystals as a Basis for Band Structure Calculations. Observation of Electron Distributions on Outermost Layers of Solid Surfaces by Penning Ionization Electron Spectroscopy. Observations of Local Electron Distributions in Molecular Orbitals. Accurate Hellmann Feynman Force Method for the Study of the First and Second Derivatives of Potential Energy Hypersurface. The Calculation of Spectroscopic Data by the SCC X? Method. On Correlated One Electron Energies in the HFS and HFG Schemes. On the Atomic Wavefunctions Generated by the Hartree Fock Slater Method X?HF and the Modified Hartree Fock Slater Method ?aHF which Includes Self Interaction Explicitly. Ab Initio Calculations Incorporating Desirable Options for Large Molecules and Solids: a Competitive Completely General Alternative to Local Density Methods for Many Systems.", "author_names": [ "Jens Peder Dahl", "John Scales Avery" ], "corpus_id": 118937456, "doc_id": "118937456", "n_citations": 215, "n_key_citations": 2, "score": 0, "title": "Local Density Approximations in Quantum Chemistry and Solid State Physics", "venue": "", "year": 1984 }, { "abstract": "1. Atoms as Constituents of Matter. 1.1 Introduction. 1.2 Atomic Scale. 1.3 One Electron Atoms and the Hydrogen Atom. 1.4 Central Field Approximation. 1.5 Shell Structure of Atoms and Periodicity of the Elements. 1.6 Stationary States of Atoms I. 1.7 Stationary States of Atoms II. 2. System of Protons and Electrons. 2.1 General Comments. 2.2 Electronic State of a Hydrogen Molecule. 2.3 Systems Made of Hydrogen Molecules. 2.4 Metallic State at High Density. 2.4.1 Electron Electron Interaction. 2.4.2 Interaction Between Protons and Electrons. 2.4.3 Motion of Protons. 2.5 Phase Diagram of the Proton Electron System. 3. Helium. 3.1 Characteristics of Helium. 3.2 Superfluidity. 3.3 Phonons and Rotons. 3.4 Liquid 3He Fermi Liquid. 3.4.1 Basic Ideas of the Fermi Liquid Theory. 3.4.2 The Equilibrium Properties. 4. Super fluid Helium 3. 4.1 Basic Properties. 4.1.1 Thermodynamic Properties. 4.1.2 Transport Phenomena. 4.1.3 Nuclear Magnetic Resonance (NMR) Experiments. 4.2 Spin Triplet P Wave Pairing. 4.2.1 Cooper Pair. 4.2.2 Generalization of the BCS Theory. 4.2.3 Order Parameters of the Spin Triplet P Wave Superfluid. 4.2.4 ABM State and BW State. 4.3 Physical Properties of ABM and BW States. 4.3.1 Energy Gap. 4.3.2 Normal (Super) Fluid Component ?n(?s) 4.3.3 Susceptibility. 4.4 Fermi Liquid Effects. 4.5 Nuclear Spin Dynamics. 4.5.1 Small Oscillations. 4.5.2 Ringing. 4.6 Texture and Superfluidity. 5. Metals. 5.1 Characteristics of Metals. 5.2 Band Theory of Metals. 5.3 Fermi Surface. 5.4 Pseudopotential of Simple Metals. 5.5 Structure of Simple Metals, 5.6 Transition Metals. 5.7 Alloys. 5.8 Superconductivity. 6. Nonmetals. 6.1 Molecular Crystals. 6.2 Ionic Crystals. 6.3 Covalent Crystal. 6.4 Hydrogen Bonded Crystals. 6.5 Electron Theory of Nonmetals (Semiconductors) 6.6 Semimetals. 6.7 Properties of Matter Under High Pressure. 7. Localized Electron Approximation. 7.1 A Simple Model for Tetrahedrally Bonded Semiconductors. 7.2 Bond Orbital Model (BOM) 7.2.1 Effective Charge. 7.2.2 Dielectric Constant. 7.3 Cohesive Energy and Stability of Crystal Structures. 7.4 Relationship Between the BOM and EPM. 8. Magnetism. 8.1 Magnetic Properties of Solids. 8.2 Magnetic Properties of Simple Solids. 8.3 Mechanism of Spin Polarization and the Electronic State in Solids. 8.4 Configurations of Spin Polarization in Magnetic Ordered States. 8.4.1 Magnetic Anisotropy Energy and Crystal Fields. 8.4.2 Magnetic Order in Insulators. 8.4.3 Magnetic Order due to the Double Exchange Interaction. 8.4.4 Magnetic Order in Metals. 8.5 Collective Motion in Ordered States and Phase Transitions. 8.6 Magnetic Properties of Dilute Alloys. 8.7 Applications of Magnetic Measurements for Condensed Matter. 9. Magnetic Properties of Dilute Alloys the Kondo Effect. 9.1 Recent Investigations of the Kondo Effect. 9.2 A Survey of Recent Experiments. 9.3 Yosida Yamada Theory. 9.4 Renormalization Group Approach. 10. Random Systems. 10.1 Periodic and Aperiodic Systems. 10.2 Point Defects. 10.3 Line Imperfections and Dislocations. 10.4 Cradle of Random Systems Melting of Crystals and Order Disorder Phase Transition in Alloys. 10.5 Noncrystalline Solids. 10.6 Liquid Metals and Electronic and Vibrational States of Random Systems. 11. Coherent Potential Approximation (CPA) 11.1 Survey. 11.2 A Few Examples of Experimental Results. 11.2.1 Optical Absorption Spectra in Mixed Ionic Crystals. 11.2.2 Photoemission of Transition Metal Alloys and Noble Metal Alloys. 11.2.3 Magnetic Moments and Electron Specific Heat of Ferromagnetic Alloys. 11.3 Computer Simulations and Exact Solutions. 11.3.1 Results of Computer Experiments. 11.3.2 Exact Results. 11.4 Model Hamiltonian. 11.5 One Particle Green's Function. 11.6 Approximations before CPA. 11.6.1 Rigid Band Model (the Lowest Order Virtual Crystal Model) 11.6.2 Virtual Crystal Model. 11.6.3 Dilute Limit. 11.6.4 The Average t Matrix Approximation (ATA) 11.7 Derivation and the Characteristic Features of the CPA. 11.7.1 Rigid Band Limit. 11.7.2 Virtual Crystal Limit. 11.7.3 Dilute Limit. 11.7.4 Split Band Limit. 11.8 Applications of the CPA. 11.8.1 A One Dimensional AB Alloy. 11.8.2 Phonon Density of States of an Isotopically Disordered Model System. 11.8.3 Density of States of a Three Dimensional Alloy. 11.8.4 Optical Absorption Spectra of Mixed Crystals. 11.8.5 Density of States of Transition and Noble Metal Alloys. 11.8.6 Ferromagnetic Alloys. 11.9 Universality of the CPA. 11.9.1 Cluster Effects (Multi Site Approximations) 11.9.2 Extension to Systems with Off Diagonal Disorder. 11.9.3 Extension to Systems with Both Diagonal and Off Diagonal Disorder. 11.9.4 Extension to Structurally Disordered Systems Composed of Single Species. 11.9.5 Extension to the Multi Band Hamiltonian. 11.9.6 Extension of CPA to the Calculations of Other Physical Quantities. References.", "author_names": [ "Song Yuan Wu Sheng" ], "corpus_id": 12871505, "doc_id": "12871505", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "The Structure and Properties of Matter", "venue": "Nature", "year": 1928 } ]

[ { "abstract": "Abstract The magnetic properties based on the armchair edged graphene nanoribbons (AGNRs) are less studied in currently existing works. Here, the edge modification of AGNR by the transition metal Mn (AGNR Mn) and further functionalized with monohydrogenation (AGNR Mn H) and dihydrogenation (AGNR Mn H2) are considered. Our calculations from first principles method show that they posses three triplet antiferromagnetic (AFM) states, which are all semiconductoring for AGNR Mn and metallic for AGNR Mn H2, but semiconductoring or metallic for AGNR Mn H. Interestingly, at ferromagnetic (FM) state AGNR Mn H and AGNR Mn H2 are a half metal with bandgaps 0.46 and 0.97 eV, respectively. AGNR Mn H2 featuring both the stable magnetic ordering and the highest energy stability are predicted, as well as the calculated Gibbs free energy unveils that these three structures can stably exist in a different chemical potential range in experiment. Also shown is that the perfect spin polarization in a very large bias region and a spin valve effect with a large magnetoresistance can be achieved in a magnetic device based on AGNR Mn H2.", "author_names": [ "Z B Zhu", "D J Wang", "Zhenhua Zhang", "Ming Qiu" ], "corpus_id": 138005686, "doc_id": "138005686", "n_citations": 12, "n_key_citations": 0, "score": 1, "title": "Magnetic structures and magnetic device properties of edge modified armchair edged graphene nanoribbons", "venue": "", "year": 2016 }, { "abstract": "The electronic and magnetic structures of graphene nanoribbons (GNRs) with various edge structures passivated by P atoms are investigated systematically, and compared with H passivation as well. GNRs with the entire reconstructed Klein edge or armchair edge are found to be nonmagnetic regardless of P or H passivation. However, if the edge of GNRs is a mixture of zigzag edge and reconstructed Klein edge, they are nonmagnetic for H passivation but significantly magnetic for P passivation, which could be attributed to the \"charge transfer doping\" effect. And the corresponding magnetic device shows a noticeable negative differential resistance phenomenon and an excellent spin filtering effect under AP configuration, which originate from the special energy band structure. The GNRs with zigzag edge, reconstructed Klein edge, or mixed edge shapes are all metals in the nonmagnetic state regardless of the H or P atoms involved. The relationship between the energy gap and the width in armchair edged GNRs by P passivation with a dimer structure also satisfies the 3p periodicity, but different in detail from the case of H passivation. The calculated edge formation energy indicates that P passivated GNRs are energetically more favorable, suggesting that they can stably exist in the experiment.", "author_names": [ "Z L Yu", "D J Wang", "Z B Zhu", "Z H Zhang" ], "corpus_id": 25331005, "doc_id": "25331005", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Magneto electronic properties of graphene nanoribbons with various edge structures passivated by phosphorus and hydrogen atoms.", "venue": "Physical chemistry chemical physics PCCP", "year": 2015 }, { "abstract": "Abstract The edge state, which is a peculiar magnetic state in zigzag edged graphene nanoribbons (GNRs) originating from an electron electron correlation in an edge localized p state, has promising applications for magnetic and spintronics devices and has attracted much attention of physicists, chemists, and engineers. For deeper understanding the edge state, precise fabrication of edge structures in GNRs has been highly demanded. We focus on [a.b]periacene, which are polycyclic aromatic hydrocarbons (PAHs) that have zigzag and armchair edges on molecular periphery, as a model compound for the understanding and actually prepare and characterize them. This review summarizes our recent studies on the origin of the edge state by investigating [a.b]periacene in terms of the relationship between the molecular structure and spin localizing character.", "author_names": [ "Akihito Konishi", "Yasukazu Hirao", "Hiroyuki Kurata", "Takashi Kubo" ], "corpus_id": 122622250, "doc_id": "122622250", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Investigating the edge state of graphene nanoribbons by a chemical approach: Synthesis and magnetic properties of zigzag edged nanographene molecules", "venue": "", "year": 2013 }, { "abstract": "Abstract The structure dependent electronic properties of suspended graphene nanoribbon (GNR) have still been important issues. However, these properties have been rarely investigated experimentally due to technical difficulties to produce high quality suspended GNRs and the identification of atomic structures. Here, we report the electronic properties of suspended GNRs by in situ transmission electron microscopy observations to simultaneously obtain the structural information while measuring the current voltage (I V) curves. The suspended GNRs could be obtained by convergent electron beam nanosculpting after careful cleaning by current annealing. The I V curves were measured for GNRs with a mixture of both zigzag and armchair edges (MGNR) with widths of 3.7 to 1.9 nm and also zigzag edge GNRs (ZGNR) with widths of 1.7 to 1.2 nm. The I V curves for the ZGNRs were different from those of the MGNRs, as follows. (1) The ZGNRs showed a sharp increase at the threshold voltage in differential conductance voltage curves. (2) The band gaps measured for ZGNRs were smaller than the band gaps calculated using the GW approximation. (3) The threshold voltage increased with the GNR length. These findings support magnetic insulator and nonmagnetic metal nonequilibrium phase transitions as theoretically predicted. Narrow and short ZGNR represents the potential for further nanosized switching devices.", "author_names": [ "Chunmeng Liu", "Jiaqi Zhang", "Manoharan Muruganathan", "Hiroshi Mizuta", "Yoshifumi Oshima", "Xiaobin Zhang" ], "corpus_id": 218937812, "doc_id": "218937812", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Origin of nonlinear current voltage curves for suspended zigzag edge graphene nanoribbons", "venue": "", "year": 2020 }, { "abstract": "Recent outbreaks in bottom up chemical techniques have demonstrated the synthesis of atomically perfect zigzag graphene nanoribbons (ZGNRs) and of their corresponding analogs with phenyl edge functionalization [P. Ruffieux et al. Nature 531, 489 (2016) Since spin polarized currents can be generated at the edges of the ZGNRs, the control of phenyl decoration at the zigzag edges could accurately tune the electronic properties of these carbon based nanoribbons. In the present paper, using first principles calculations and a Landauer Buttiker approach, the electronic and magnetic properties as well as the spin resolved transmissions are investigated in various phenyl edge modified ZGNRs. The understanding of the spin dependent transport properties in relation to the atomic structure opens the way to design devices such as spin valves for future spintronics applications.", "author_names": [ "Leandro Salemi", "Aurelien Lherbier", "Jean-Christophe Charlier" ], "corpus_id": 126636362, "doc_id": "126636362", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Spin dependent properties in zigzag graphene nanoribbons with phenyl edge defects", "venue": "", "year": 2018 }, { "abstract": "Graphene nanoribbons, quasi one dimensional structures of carbon, are fascinating materials. These structures can be constructed as strips of graphene sheet, the two dimentional honeycomb lattice of carbon with sp2 hybridization. Geometrically two main types of slice can be cut from a graphene sheet, with zigzag edge and armchair edge (Niimi05; Kobayashi05) The edge geometry is the key parameter which determines the electronic properties of the nanoribbons. Although the two dimensional graphene is a zero band gap semi metal, electronic structure of nanoribbons depend on their edge geomtery (Saito92; Klein94; Fujita96; Son06a) A simple tight binding model with one orbital per atom predicts that zigzag nanoribbons are metallic. But density functional calculations shows that all graphene nanoribbons are semiconductors at their ground state with band gaps which depend on their width and edge geometry, closing at infinite width, i. e. infinite graphene. Moreover, the electronic structure of graphene nanoribbons can be modified by chemical functionalization, such as functionalization by various atomic sepcies or by functional groups (Maruyama04a; Gunlycke07; Hod07; Gorjizadeh08) A large variety of electronic and magnetic properties, such as semiconducting with a wide range of band gap, metallic, ferromagnetic, antiferromagnetic, half metallic, half semiconducting, can be obtained by chamical modifications of the nanoribbons. Modification of the edge or using an adsorbate or substitution of carbons of the nanoribbon with an appropriate host are different options of functionalizations of these materials. These properties, along with the ballistic electronic transport, and the quantum Hall effect (Novoselov05a; Zhang05) and high carrier mobility (Novoselov05a) cause these quasi 1D materials to be promising candidates for nanoelectronics applications (Novoselov04b; Son06b; Obradovic06; Li08; Hod09; Zhu10) Various junctions can be constructed by connecting nanoribbons of different widths and types with perfect atomic interface, and electronic device can be integrated on them by selective chemical funtionalization on a single nanoribbon sheet (Huang07; Yan07; Gorjizadeh08) In order to achieve their potential for these applications it is essential to have a better understanding of the electronic structure of graphene nanoribbons and have ability to control them. From a practical point of view, when nanoribbons are fabricated", "author_names": [ "Narjes Gorjizadeh", "Yoshiyuki Kawazoe", "Amir A Farajian" ], "corpus_id": 53617150, "doc_id": "53617150", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Electronic and Transport Properties of Defected Graphene Nanoribbons", "venue": "", "year": 2011 }, { "abstract": "We theoretically investigate the spin dependent transport for the system of an armchair edge graphene nanoribbon (AGNR) between two ferromagnetic (FM) leads with arbitrary polarization directions at low temperatures, where a magnetic insulator is deposited on the AGNR to induce an exchange splitting between spin up and down carriers. By using the standard nonequilibrium Green's function (NGF) technique, it is demonstrated that the spin resolved transport property for the system depends sensitively on both the width of AGNR and the polarization strength of FM leads. The tunneling magnetoresistance (TMR) around zero bias voltage possesses a pronounced plateau structure for a system with semiconducting 7 AGNR or metallic 8 AGNR in the absence of exchange splitting, but this plateau structure for the 8 AGNR system is remarkably broader than that for the 7 AGNR one. Interestingly, an increase of the exchange splitting D suppresses the amplitude of the structure for the 7 AGNR system. However, the TMR is much enhanced for the 8 AGNR system under a bias amplitude comparable to the splitting strength. Further, the current induced spin transfer torque (STT) for the 7 AGNR system is systematically larger than that for the 8 AGNR one. The findings here suggest the design of GNR based spintronic devices by using a metallic AGNR, but it is more favorable to fabricate a current controlled magnetic memory element by using a semiconducting AGNR.", "author_names": [ "Benhu Zhou", "Xiongwen Chen", "Benliang Zhou", "Kai Ding", "Guanghui Zhou" ], "corpus_id": 30846849, "doc_id": "30846849", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Spin dependent transport for armchair edge graphene nanoribbons between ferromagnetic leads.", "venue": "Journal of physics. Condensed matter an Institute of Physics journal", "year": 2011 }, { "abstract": "Utilizing first principle calculations, we perform a systematic study on the electronic and magnetic properties of recently proposed graphene like Be3C2 nanostructures. We found that although the Be3C2 nanosheet exhibits a Dirac feature in the nonmagnetic state, an intrinsic antiferromagnetism is preferred and it opens a sizeable band gap of 2.75 eV at the Dirac point. The edge stabilities of Be3C2 nanoribbons (Be3C2NRs) are revealed in detail, and indicate that the armchair and zigzag edges with Be and C terminations are all possibly obtained by careful control of the H and Be chemical potentials. Akin to the Be3C2 nanosheet, these Be3C2NRs are also antiferromagnetic semiconductors regardless of the edge shapes and terminations, whose band gaps are all insensitive to the ribbon width. Peculiar spintronic behaviors can be induced in the zigzag Be3C2NRs by electric fields, which can transform the Be terminated nanoribbons into half metals and turn the C terminated ones into bipolar semiconductors or even spin gapless semiconductors. Similar electronic structures are also present in Be3Si2 and Be3Ge2 nanostructures, which are antiferromagnetic semiconductors with smaller band gaps. The valence and conduction band edges of Be3C2NRs straddle the redox potentials of water, and are suitable for photocatalytic water splitting, while for the Be3Si2 and Be3Ge2 nanostructures, the band edges could form a type II band alignment with the MoS2 nanosheet, for which the combined hetero nanostructures possess a high power conversion efficiency of up to 14 17% for photovoltaic solar cells. Our study demonstrates that beryllium group IV nanostructures exhibit versatile electronic and magnetic properties, which endow them with many potential applications in nano electrics and nano energy devices.", "author_names": [ "Yi Ding", "Yanli Wang" ], "corpus_id": 139981815, "doc_id": "139981815", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Intrinsic Magnetism and Electronic Structure of Graphene like Be3C2 Nanoribbons and Their Si, Ge Analogues: A Computational Study", "venue": "", "year": 2017 }, { "abstract": "We analyze theoretically electronic, magnetic, and thermoelectric properties of narrow carbon polymers. Such nanoribbons, which can be obtained chemically via bottom up approach from the appropriate monomers, may exhibit extremely interesting properties from application point of view if modified with substitution Al/N atoms or functionalized with NOCH3 group. Our investigations, based on ab initio calculations, show that such modification may considerably narrow the bandgap with respect to pristine structures. Also, magnetic moments ordered ferromagnetically can be generated along modified edges, which results in the spin dependent band structure giving rise to remarkable spin effects, giving strongly enhanced spin Seebeck coefficient. These results suggest that modified polymeric graphene nanoribbons would have a great potential for applications in spintronic devices.", "author_names": [ "Krzysztof Zberecki", "R Swirkowicz" ], "corpus_id": 125893188, "doc_id": "125893188", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Thermoelectric phenomena in chemically synthesized graphene nanoribbons with substitution atoms and functional groups", "venue": "", "year": 2016 }, { "abstract": "Effects of magnetic antidots on the transport properties of zigzag edged graphene nanoribbons ZGNRs are investigated by spin polarized first principles calculations combined with a nonequilibrium Green's function technique. Specifically, the effects of antidots or holes with regular shapes rectangular and triangular are studied. It is found that rectangular holes with a zero total spin S0 and triangular holes with a finite spin S0 cause different effects on the equilibrium conductance of ZGNRs. A rectangular hole with zigzag edges parallel to the ribbon edges blocks the transmission of the band edges of both the valence band and the conduction band from both the spin up channel and the spin down channel. Thus a much wider transmission gap than the pristine ZGNRs can be observed. However, a triangular hole with zigzag edges blocks transmission from only one spin channel in either the valence band edge or the conduction band edge. Thus the gap width in the total conductance is not affected in this case. The difference originates from the different energy shift of the valence band and conduction band relative to Fermi energy as a result of two effects: finite size effect and spin splitting from the antidot induced effective internal magnetic field. Graphene nanostructures are supposed to be very important building blocks in future nanoelectronic devices due to their remarkable structural and electronic properties. Among them, graphene nanoribbons GNRs have attracted intensive attention 1 12 and it is found that the properties of GNRs are highly dependent on their sizes and edge shapes. Tightbinding calculations show that armchair edged GNRs AGNRs can be either metallic or semiconducting depending on their widths 8,12 while first principles calculations show that AGNRs are always semiconducting with an energy gap scaling inversely to the GNR width. 8 10 More interestingly, in the zigzag edged GNRs ZGNRs, magnetic ordering is formed due to the unpaired and edge electrons. Two most stable spin configurations have been observed: ferromagnetic FM and antiferromagnetic AF, 13 which mean that the localized edge states on the two sides are FM coupled or AF coupled. Tight binding calculations show that the ZGNRs are always metallic 12 while first principles calculations show that it is metallic only in the FM configuration. There is always an energy gap in the AF configuration. Calculations also show that the most stable configuration is the AF state with the states of different spins in the valence bands and conduction bands localized on different edges while the energy of the states with different spins is degenerate. 5,8 Meanwhile, quantum dots and antidots made by graphene are another kind of graphene nanostructures which initiate great interests. 14 20 The dots are just graphene molecules with finite size in all directions while antidots are holes in graphene with some kinds of dots cut away from it. Just like in ZGNRs, magnetism can also be formed in graphene molecules with zigzag edges. 15 In a graphene molecule with rectangular or hexagonal edges, magnetic moments with the same magnitude and different signs are always formed on the two opposite zigzag edges. Thus the total spin S0 in such systems is exactly zero. However, in a molecule with triangular zigzag edges, exactly the same magnetic moments are observed on all edges. So the total spin S0 is nonzero. Like in ZGNRs, the local magnetism in graphene molecules arises from the spin polarized edge states localized on the zigzag edges. The local magnetism in graphene nanostructures may qualify graphene nanoribbons and molecules with zigzag edges as promising candidates for application in the spintronic devices. Therefore, the study of spin polarized transport through these nanostructures are quite interesting. In this work, we build graphene based devices by combining graphene nanoribbons and antidots with zigzag edges and investigate the electron transport in them. Specifically, we study the effects of graphene antidots or holes on the transport properties of ZGNRs. Two kinds of antidots will be considered: rectangular hole and triangular hole. The model structure is constructed as follows: the scatter", "author_names": [ "Xiaohong Zheng", "Guoren Zhang", "Zhi Zeng", "Victor M Garcia-Suarez", "Colin J Lambert" ], "corpus_id": 122827582, "doc_id": "122827582", "n_citations": 35, "n_key_citations": 0, "score": 0, "title": "Effects of antidots on the transport properties of graphene nanoribbons", "venue": "", "year": 2009 } ]

[ { "abstract": "Harvesting visible light of the solar spectrum by coupled semiconductor based systems is advantageous for photocatalytic as well as photovoltaic applications. One pot synthesis of several CdS/CeO2 nanomaterials has been carried out without using expensive surfactants, capping agents and molecular linkers. Various techniques such as X ray diffraction (XRD) transmission electron microscopy (TEM) X ray photoelectron spectroscopy (XPS) diffuse reflectance UV vis spectroscopy, Raman spectroscopy and BET surface area were used to characterize the samples. XRD and Raman spectroscopic data provided the information about the presence of both CdS and CeO2 phases. TEM proves the proper dispersion and well connectivity between the CdS and CeO2 which may be due to the single step synthesis of the composites. UV vis spectroscopy reveals the absorption in both UV and visible regions due to the presence of both CeO2 and CdS. The visible light activity of the composites have been ascribed by the H2 production from water by using sacrificial reagents, simultaneous removal of phenol and Cr(VI) from aqueous streams. Among the synthesized composites CdS/CeO2 (1:1) has shown superior activity which can be attributed to the optimum sensitization of CeO2 which induces enhanced electron transfer from CdS to CeO2 that decreases the exciton recombination.", "author_names": [ "A Daya Mani", "Swarnava Nandy", "Ch Subrahmanyam" ], "corpus_id": 93435507, "doc_id": "93435507", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Synthesis of CdS/CeO2 nanomaterials for photocatalytic H2 production and simultaneous removal of phenol and Cr(VI)", "venue": "", "year": 2015 }, { "abstract": "Harvesting visible light of the solar spectrum by coupled semiconductor based systems where sensitization of a wide band gap semiconductor with a small band gap semiconductor advantageous for photocatalytic as well as photovoltaic applications. A facile one pot synthesis of several CdS/CeO2 hetero nanostructures has been carried out without using expensive surfactants, capping agents and molecular linkers. Various techniques such as Xray diffraction (XRD) Transmission electron microscopy (TEM) X ray photoelectron spectroscopy (XPS) diffuse reflectance UV Vis spectroscopy, Raman spectroscopy and BET surface area were used to characterize the samples. XRD and Raman spectroscopic data provided the information about the presence of both CdS and CeO2 phases. TEM proves the proper dispersion and well connectivity between the CdS and CeO2 which may be due to the single step synthesis of the composites. XPS gives the information about the presence of elements such as Cd, Ce, O, S, C and N, where the presence of latter two elements can be attributed to the in situ C and N doping during the combustion synthesis. UV visible spectroscopy reveals the absorption in both UV and visible regions due to the presence of both CeO2 and CdS. The visible light activity of the composites have been ascribed by the H2 production from water by using sacrificial reagents, simultaneous removal of phenol and Cr(VI) from aqueous streams. Among the synthesized composites CdS/CeO2 (1:1) has shown superior activity which can be attributed to the optimum sensitization of CeO2 which induces enhanced electron transfer from CdS to CeO2 that decreases the exciton recombination.", "author_names": [ "Swarnava Nandy", "Subrahmanyam Ch" ], "corpus_id": 137951067, "doc_id": "137951067", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Synthesis of CdS/CeO2 hetero nanostructures for Photocatalytic H2 production and simultaneous Removal of phenol and Cr(VI)", "venue": "", "year": 2014 }, { "abstract": "TiO2 nanotube arrays were prepared by electrochemical anodization on pure Ti surfaces.The products were characterized by X ray diffraction,scanning electron microscopy and electrochemical workstation.The results showed that the prepared sample was anatase with a diameter of about 100 nm and a tube length of about 2mm.The maximum photocurrent could be achieved when the bias potential of 0.5 V was applied on the TiO2 nanotube array electrode.The photoelectrocatalytic properties of the TiO2 nanotube array electrode were evaluated by the simultaneous removal of phenol and Cr(VI).The effects of catalytic processes,pH values,and various initial concentrations of Cr(VI) and phenol on the removal efficiency of phenol and Cr(VI) were investigated.The results indicated that in the photoelectrocatalytic mode,phenol and Cr(VI) removal ratios were 86.7% and 96.9%,respectively,while in the photocatalytic mode they were 48.2% and 65.2%,respectively.The removal efficiency by photoelectrocatalysis was higher than that by photocatalysis.The acidic solutions were favorable for the photoelectrocatalytic simultaneous removal of Cr (VI) and phenol,and the optimum pH was 2.In the phenol Cr(VI) co existed system,phenol and Cr(VI) were more efficiently eliminated than in the single phenol or Cr(VI) system.The reduction of Cr(VI) and the oxidation of phenol produced a synergistic effect,which promoted the simultaneous removal of Cr(VI) and phenol.", "author_names": [ "Huang Lang-huan" ], "corpus_id": 100943604, "doc_id": "100943604", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Simultaneous Removal of Phenol and Cr(VI) by TiO_2 Nanotube Array Photoelectrocatalysis", "venue": "", "year": 2011 }, { "abstract": "", "author_names": [ "Houjin Wang", "Xiaojing Wu", "Yaling Wang", "Zibin Jiao", "Sheng Yan", "Lan Huang" ], "corpus_id": 100922213, "doc_id": "100922213", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Simultaneous Removal of Phenol and Cr(VI) by TiO 2 Nanotube Array Photoelectrocatalysis: Simultaneous Removal of Phenol and Cr(VI) by TiO 2 Nanotube Array Photoelectrocatalysis", "venue": "", "year": 2011 }, { "abstract": "A powerful photocatalyst is the key for photocatalytic environmental purification via sunlight harvesting and utilization. In this work, novel boron doped Sn3O4 microspheres constructed from nanoplates were designed and fabricated. Density functional theory (DFT) studies were carried out to investigate the boron doping mechanism, in which DFT predicted that boron doping would enhance the light harvesting capability and the photo response of Sn3O4, which was proved by diffuse reflectance spectra (DRS) and transient photocurrent responses. Attributed to its unique porous structure, and enhanced light harvesting and high carrier utilization capabilities, the boron doped Sn3O4 microsphere exhibited high efficiency for Cr(IV) removal and azo dyestuff degradation. Moreover, an unexpected synergistic effect upon simultaneous removal of phenols (phenol, bisphenol A and p chlorophenol) and Cr(VI) was observed.", "author_names": [ "Changling Yu", "Debin Zeng", "Qizhe Fan", "Kai Yang", "Julan Zeng", "Long Wei", "Junhui Yi", "Hongbing Ji" ], "corpus_id": 213923916, "doc_id": "213923916", "n_citations": 19, "n_key_citations": 0, "score": 0, "title": "The distinct role of boron doping in Sn3O4 microspheres for synergistic removal of phenols and Cr(vi) in simulated wastewater", "venue": "", "year": 2020 }, { "abstract": "Simultaneous phenol and Cr(VI) bioremoval by two different mixed cultures, from petroleum contaminated soil (PS) and boron contaminated wastewater (BW) was investigated in regard to different culture media, pH levels (6 8) initial phenol (25 100 mg/L) and Cr(VI) (15 50 mg/L) concentrations. The optimum medium was found to be mineral salt medium tested, which contained 1% (v/v) molasses (MSM) Optimum pH values were 6 for PS and 8 for BW. All of the phenol present in the samples was mineralized regardless of its concentrations tested, Cr(VI) bioremoval was enhanced by the increase in phenol concentrations, and molasses also exerted a positive effect on Cr(VI) removal, and the yields reached 100% for both pollutants, even at 13.1 mg/L Cr(VI) and 91.1 mg/L phenol concentration in PS samples. In MSM containing PS samples approximate efficiency was 100% for phenol removal; but Cr(VI) removal ratios were 64.9% and 41.7% at 25.8 mg/L and 41.3 mg/L concentrations, respectively. Finally it can be concluded that molasses stimulated Cr(VI) bioremoval at elevated phenolic conditions in the mixed microbial culture, and molasses might be of use for the bioremediation of phenol and Cr(VI) polluted wastewaters.", "author_names": [ "Nur Kocberber Kilic", "Gonul Donmez" ], "corpus_id": 42338213, "doc_id": "42338213", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Dual bioremediation of phenol and Cr(VI) by mixed microbial cultures in the presence of molasses.", "venue": "Water science and technology a journal of the International Association on Water Pollution Research", "year": 2017 }, { "abstract": "Biological treatment of industrial wastewater containing heavy metal and organic pollutant has attracted extensive attention. In this study, Cr(VI) reduction coupled with phenol degradation was investigated by the sulfate reducing bacteria (SRB) sludge with addition of zero valent iron (ZVI) The results showed that the SRB wet sludge (SWS) had a good bioactivity in the reduction of Cr(VI) only when the initial concentration of Cr(VI) was below 60 mg L 1. The addition of ZVI significantly enhanced the bioactivity and reusability of SWS, and the reduction percentage of Cr(VI) achieved 98% after SWS was successively used for seven cycles. SWS coupled with ZVI showed a high activity in phenol degradation, with more than 94% phenol being degraded in each cycle. However, in the simultaneous removal of Cr(VI) and phenol, phenol degradation was inhibited due to the toxicity of Cr(VI) to phenol degrading microbes in SWS. On the other hand, reduction of sulfate and Cr(VI) was not affected by the presence of phenol, with more than 95% of sulfate and Cr(VI) being removed at the end of the 5th cycle. This study enriches our understanding on the applications of the SRB sludge in the removal of organic and inorganic contaminants in wastewater.", "author_names": [ "Xu Han", "Tuo Zhou", "S W Xu", "Yan Zun Li", "Y -F Wang", "Yong Qiu Liu" ], "corpus_id": 100475187, "doc_id": "100475187", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Removal of Cr(VI) and phenol coupled with the reduction of sulfate by sulfate reducing bacteria sludge", "venue": "International Journal of Environmental Science and Technology", "year": 2017 }, { "abstract": "The applicability of bentonite supported nanoscale zero valent iron (B nZVI) as a catalyst to activate persulfate (PS) for the simultaneous removal of Cr(VI) and phenol was systematically investigated in this study. Experimental results demonstrated that phenol degradation was significantly enhanced under acidic condition and with oxygen supply, whereas the Cr(VI) reduction was not obviously declined. The removal efficiencies of Cr(VI) and phenol in B nZVI/PS combined system were 99.8 and 72.3% respectively. Cr(VI) reduction and phenol oxidation was simultaneously achieved in B nZVI/PS combined system, which provided a promising environmental treatment for industrial wastewater containing metal ions and organic compounds. An acidic condition was more favorable to the decomposition of persulfate for the production of sulfate radicals. Radical scavenging tests revealed that the predominant reactive oxygen species for phenol degradation was SO4( neither HO nor O2( A reaction mechanism, which involves the Cr(VI) removal mainly by the reduction of nZVI and the degradation of phenol mainly by the SO4( from the decomposition of persulfate, was proposed. These findings revealed that B nZVI/PS combined system has a potential in the environmental remediation polluted jointly by organic compounds and/or heavy metals.", "author_names": [ "Zenghui Diao", "Xiangrong Xu", "Hui Chen", "Dan Jiang", "Yuxi Yang", "Lingjun Kong", "Yuxin Sun", "Yongxia Hu", "Qin-Wei Hao", "Ling Liu" ], "corpus_id": 43259400, "doc_id": "43259400", "n_citations": 95, "n_key_citations": 0, "score": 1, "title": "Simultaneous removal of Cr(VI) and phenol by persulfate activated with bentonite supported nanoscale zero valent iron: Reactivity and mechanism.", "venue": "Journal of hazardous materials", "year": 2016 }, { "abstract": "In this work, Ag3PO4/PANI/Cr:SrTiO3 photocatalysts were designed to effectively eliminate organic pollutants including Rhodamine B and phenol from high salinity wastewater under visible light. The phase composition, optical properties, and morphology of powders were studied, and the effects of inorganic salts on removal performance of the as prepared particles were also tested. Results showed that the photocatalytic activities of Ag3PO4/PANI/Cr:SrTiO3 composites for Rhodamine B and phenol reached 100% within 10 min and 18 min, respectively. The reaction rate of pure Ag3PO4 was 7 times less than that of the ternary composite with the adding of PANI and Cr:SrTiO3. The activity of Ag3PO4/PANI/Cr:SrTiO3 remained at 92.25% after five cycles, so the photocatalytic and recyclable performance of ternary composite was greatly improved. In addition, when there was SO42 with a content of ranging from 1% to 21% the degradation activity of the ternary catalyst under visible light was not changed for Rhodamine B, which indicated that the ternary catalyst exhibited the excellent sulfate resistance ability. Results from ESR and radical trapping experiments showed that O2 and h+ made an important contribution to visible light photocatalytic activities.", "author_names": [ "Xiaochao Yu", "Yan Lin", "Haiyang Liu", "Chunping Yang", "Yanrong Peng", "Cheng Du", "Shaohua Wu", "Xiaorui Li", "Yuanyuan Zhong" ], "corpus_id": 208142428, "doc_id": "208142428", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Photocatalytic performances of heterojunction catalysts of silver phosphate modified by PANI and Cr doped SrTiO3 for organic pollutant removal from high salinity wastewater.", "venue": "Journal of colloid and interface science", "year": 2019 }, { "abstract": "This study was designed to isolate, identify and characterize micro organisms or mixed cultures capable of simultaneously removing Cr (VI) and phenol in the surrounding area of a tannery localized in Elena, Cordoba, Argentina. In addition, nutritional and physical factors were optimized in order to improve the removal efficiency in a real effluent.", "author_names": [ "Ornella M Ontanon", "Paola S Gonzalez", "Elizabeth Agostini" ], "corpus_id": 24254018, "doc_id": "24254018", "n_citations": 16, "n_key_citations": 1, "score": 0, "title": "Optimization of simultaneous removal of Cr (VI) and phenol by a native bacterial consortium: its use for bioaugmentation of co polluted effluents", "venue": "Journal of applied microbiology", "year": 2015 } ]

[ { "abstract": "Miniaturized and \"smart\" instruments capable of characterizing the mechanical properties of tiny biological tissues are needed for research in biology, physiology, and biomechanics, and can find very important clinical applications for diagnostics and minimally invasive surgery (MIS) We are developing a set of robotic microinstruments designed to augment the performance of surgeons and clinicians during MIS. These microtools are intended to restore (or even enhance) the finger palpation capabilities that the surgeon exploits to characterize tissue hardness and to measure pulsating vessels in traditional surgery, but which are substantially reduced in MIS. This paper describes the main applications and the performance of a prototype miniature robotic instrument consisting of a microfabricated microgripper, instrumented with semiconductor strain gauges as force sensors. The experimental set up used for the in vitro tests reported in this paper consists of the microprobe mounted on a workstation and teleoperated. A haptic interface provides force feedback to the operator. We have demonstrated that the system can discriminate, both qualitatively and quantitatively, tiny skin samples based on their different elastic properties, and \"feel\" microvessels on the basis of pulsating fluid flowing through them.", "author_names": [ "Arianna Menciassi", "Anna Eisinberg", "Maria Chiara Carrozza", "Paolo Dario" ], "corpus_id": 110492098, "doc_id": "110492098", "n_citations": 124, "n_key_citations": 3, "score": 1, "title": "Force sensing microinstrument for measuring tissue properties and pulse in microsurgery", "venue": "", "year": 2003 }, { "abstract": "Minimally invasive surgical robotic systems established the foundation for precise and refined surgery, and the intelligentization of robotic systems is an important direction for future development. Among the methods of intelligentization, microinstrument external force sensing is an open and challenging research area. Force sensing information is used not only to ensure that surgeons apply the appropriate amount of force but also to prevent unintentional tissue damage. Because a microinstrument is a compact and small sized construction, indirect force sensing method instead of the integration of sensors into the microinstrument is used, yielding better biocompatibility, sterilizability and monetary cost savings. This paper focuses on microinstrument tissue contact force sensing, and the microinstrument used is a three degrees of freedom cable driven manipulator. A contact force estimation strategy based on the differences in cable tension is established with consideration of the kinematics, dynamics and friction of the manipulator. A principle prototype of a surgical microinstrument force measurement system is developed, and then zero drift, hysteresis and force loading experiments are studied. Based on the experimental data of the force loading experiments, the relationship between cable tension and contact forces is established by using a bidirectional long short term memory plus multilayer perceptron network. The results show that the L2 cost of the network in the training set converges to 0.006 and that the RMSE of the network in the testing set converges to 0.053, and the network can meet the measurement requirements without overfitting. Therefore, the indirect force estimation method is a viable method of measuring forces of cable driven microinstrument and can be used to integrate force sensing information into surgical robotic systems to improve the operability of surgical robots.", "author_names": [ "Lingtao Yu", "Xiaoyan Yu", "Yongqing Zhang" ], "corpus_id": 211264784, "doc_id": "211264784", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Microinstrument contact force sensing based on cable tension using BLSTM MLP network", "venue": "Intell. Serv. Robotics", "year": 2020 }, { "abstract": "OBJECTIVES This study sought to evaluate the safety and effectiveness of catheter ablation of persistent atrial fibrillation (PsAF) using a porous tip contact force sensing catheter. BACKGROUND Although the safety and effectiveness of catheter ablation of paroxysmal atrial fibrillation are established, there are limited data on outcomes in patients with PsAF. As such, no ablation catheter is currently approved by the Food and Drug Administration for PsAF ablation. METHODS The prospective, multicenter, nonrandomized PRECEPT (Prospective Review of the Safety and Effectiveness of the THERMOCOOL SMARTTOUCH SF Catheter Evaluated for Treating Symptomatic PersistenT AF) study was conducted at 27 sites in the United States and Canada. Enrollment criteria included documented symptomatic PsAF and nonresponse or intolerance to =1 antiarrhythmic drug (Class I or III) An individualized treatment approach was used including pulmonary vein isolation with ablation of additional targets permitted at the investigators' discretion. To optimize treatment outcomes, a 3 month post ablation medication adjustment period followed by a 3 month therapy consolidation period were included. Arrhythmia recurrences were stringently monitored by monthly and symptomatic transtelephonic monitoring, electrocardiography, and Holter monitoring for up to 15 months after ablation. RESULTS Of 381 enrolled participants, 348 had the investigational catheter inserted and underwent ablation. The primary adverse event rate was 4.1% (15 events in 14 participants) Kaplan Meier analyses estimated a primary effectiveness success rate of 61.7% and a clinical success rate of 80.4% at 15 months. CONCLUSIONS The results demonstrate the clinical safety and effectiveness of PsAF ablation using contact force sensing technologies. The primary adverse event was within the expected range and similar to those reported in historical studies of paroxysmal AF ablation. (Prospective Review of the Safety and Effectiveness of the THERMOCOOL SMARTTOUCH SF Catheter Evaluated for Treating Symptomatic PersistenT AF; NCT02817776)", "author_names": [ "Moussa Mansour", "Hugh Calkins", "Jose Osorio", "Scott J Pollak", "Daniel Melby", "Francis E Marchlinski", "Charles A Athill", "Craig Delaughter", "Anshul M Patel", "Philip J Gentlesk", "Brian DeVille", "Laurent Macle", "Kenneth A Ellenbogen", "Srinivas R Dukkipati", "Vivek Y Reddy", "Andrea Natale" ], "corpus_id": 218938615, "doc_id": "218938615", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Persistent Atrial Fibrillation Ablation With Contact Force Sensing Catheter: The Prospective Multicenter PRECEPT Trial.", "venue": "JACC. Clinical electrophysiology", "year": 2020 }, { "abstract": "Traditional gait analysis systems based on 3D motion capture system require large, expensive equipment and specialists to operate the system, presenting time and space constraints. Although various studies have been conducted on developing wearable gait analysis devices, the results were discontinuous, there were limitations in dividing the gait phases, and appropriate responses to changes in physical conditions and walking speed were not demonstrated. To overcome these problems, the present study developed an insole device fitted with force sensing resistors for the measurement of the ground reaction force, and designed a gait analysis technique based on results from a gait experiment conducted on eight healthy male adults. This novel gait analysis algorithm examined the forward and lateral centers of the pressure values generated during gait, ratio of these two values for the division of the gait cycle into eight phases, and identification of the point when the weight support transition between the two feet occurred. The data acquisition system (DAS) comprising the developed insole device and wireless data transceiver, is expected to be applicable for activities of daily living because it can be manufactured as a small, lightweight wearable device, and the proposed gait analysis technique is unaffected by the walking speed and physical conditions of the wearer.", "author_names": [ "Ji Su Park", "Chang Min Lee", "Sang-Mo Koo", "Choong Hyun Kim" ], "corpus_id": 213732620, "doc_id": "213732620", "n_citations": 8, "n_key_citations": 1, "score": 0, "title": "Gait Phase Detection Using Force Sensing Resistors", "venue": "IEEE Sensors Journal", "year": 2020 }, { "abstract": "We theoretically investigate optomechanical force sensing via precooling and quantum noise cancellation in two coupled cavity optomechanical systems. We show that force sensing based on the reduction of noise can be used to dramatically enhance the force sensing and that the precooling process can effectively improve the quantum noise cancellation. Specifically, we examine the effect of optomechanical cooling and noise reduction on the spectral density of the noise of the force measurement; these processes can significantly enhance the performance of optomechanical force sensing, and setting up the system in the resolved sideband regime can lead to an optimization of the cooling processes in a hybrid system. Such a scheme serves as a promising platform for quantum back action evading measurements of the motion and a framework for an optomechanical force sensor.", "author_names": [ "Tesfaye Tadesse Gebremariam", "Ye-Xiong Zeng", "Mojtaba Mazaheri", "Chong Li" ], "corpus_id": 203039971, "doc_id": "203039971", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Enhancing optomechanical force sensing via precooling and quantum noise cancellation", "venue": "Science China Physics, Mechanics Astronomy", "year": 2019 }, { "abstract": "Mechanical forces are fundamental in cardiovascular biology, and deciphering the mechanisms by which they act remains a testing frontier in cardiovascular research. Here, we raise awareness of 2 recently discovered proteins, Piezo1 and Piezo2, which assemble as transmembrane triskelions to combine exquisite force sensing with regulated calcium influx. There is emerging evidence for their importance in endothelial shear stress sensing and secretion, NO generation, vascular tone, angiogenesis, atherosclerosis, vascular permeability and remodeling, blood pressure regulation, insulin sensitivity, exercise performance, and baroreceptor reflex, and there are early suggestions of relevance to cardiac fibroblasts and myocytes. Human genetic analysis points to significance in lymphatic disease, anemia, varicose veins, and potentially heart failure, hypertension, aneurysms, and stroke. These channels appear to be versatile force sensors, used creatively to inform various force sensing situations. We discuss emergent concepts and controversies and suggest that the potential for new important understanding is substantial.", "author_names": [ "David J Beech", "Antreas C Kalli" ], "corpus_id": 202686708, "doc_id": "202686708", "n_citations": 50, "n_key_citations": 0, "score": 0, "title": "Force Sensing by Piezo Channels in Cardiovascular Health and Disease", "venue": "Arteriosclerosis, thrombosis, and vascular biology", "year": 2019 }, { "abstract": "OBJECTIVES To provide a systematic overview of the literature assessing the value of haptic and force feedback in current simulators teaching laparoscopic surgical skills. DATA SOURCES The databases of Pubmed, Cochrane, Embase, Web of Science, and Google Scholar were searched to retrieve relevant studies published until January 31st, 2017. The search included laparoscopic surgery, simulation, and haptic or force feedback and all relevant synonyms. METHODS Duplicates were removed, and titles and abstracts screened. The remaining articles were subsequently screened full text and included in this review if they followed the inclusion criteria. A total of 2 types of feedback have been analyzed and will be discussed separately: haptic and force feedback. RESULTS A total of 4023 articles were found, of which 87 could be used in this review. A descriptive analysis of the data is provided. Results of the added value of haptic interface devices in virtual reality are variable. Haptic feedback is most important for more complex tasks. The interface devices do not require the highest level of fidelity. Haptic feedback leads to a shorter learning curve with a steadier upward trend. Concerning force feedback, force parameters are measured through force sensing systems in the instrument and/or the environment. These parameters, especially in combination with motion parameters, provide box trainers with an objective evaluation of laparoscopic skills. Feedback of force use both real time and postpractice has been shown to improve training. CONCLUSIONS Haptic feedback is added to virtual reality simulators to increase the fidelity and thereby improve training effect. Variable results have been found from adding haptic feedback. It is most important for more complex tasks, but results in only minor improvements for novice surgeons. Force parameters and force feedback in box trainers have been shown to improve training results.", "author_names": [ "Evelien M Overtoom", "Tim Horeman", "Frank Willem Jansen", "Jenny Dankelman", "Henk W R Schreuder" ], "corpus_id": 51929988, "doc_id": "51929988", "n_citations": 30, "n_key_citations": 0, "score": 0, "title": "Haptic Feedback, Force Feedback, and Force Sensing in Simulation Training for Laparoscopy: A Systematic Overview.", "venue": "Journal of surgical education", "year": 2019 }, { "abstract": "Nanometer scale structures with high aspect ratios such as nanowires and nanotubes combine low mechanical dissipation with high resonance frequencies, making them ideal force transducers and scanning probes in applications requiring the highest sensitivity. Such structures promise record force sensitivities combined with ease of use in scanning probe microscopes. A wide variety of possible material compositions and functionalizations is available, allowing for the sensing of various kinds of forces. In addition, nanowires possess quasi degenerate mechanical mode doublets, which allow for sensitive vectorial force and mass detection. These developments have driven researchers to use nanowire cantilevers in various force sensing applications, which include imaging of sample surface topography, detection of optomechanical, electrical, and magnetic forces, and magnetic resonance force microscopy. In this review, we discuss the motivation behind using nanowires as force transducers, explain the methods of force sensing with nanowire cantilevers, and give an overview of the experimental progress so far and future prospects of the field.", "author_names": [ "Floris R Braakman", "Martino Poggio" ], "corpus_id": 88506163, "doc_id": "88506163", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Force sensing with nanowire cantilevers.", "venue": "Nanotechnology", "year": 2019 }, { "abstract": "We investigate quantum squeezing enhanced weak force sensing via a nonlinear optomechanical resonator containing a movable mechanical mirror and an optical parametric amplifier (OPA) Herein, we determined that tuning the OPA parameters can considerably suppress quantum noise and substantially enhance force sensitivity, enabling the device to extensively surpass the standard quantum limit. This indicates that under realistic experimental conditions, we can achieve ultrahigh precision quantum force sensing by harnessing nonlinear optomechanical devices.", "author_names": [ "Wen Zhao", "Sheng-Dian Zhang", "Adam Miranowicz", "Hui Jing" ], "corpus_id": 168170060, "doc_id": "168170060", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Weak force sensing with squeezed optomechanics", "venue": "Science China Physics, Mechanics Astronomy", "year": 2019 }, { "abstract": "Abstract Few technologies exist that can provide quantitative data on forces within the mitral valve apparatus. Marker based strain measurements can be performed, but chordal geometry and restricted optical access are limitations. Foil based strain sensors have been described and work well, but the sensor footprint limits the number of chordae that can be measured. We instead utilized fiber Bragg grating (FBG) sensors optical strain gauges made of 125 mm diameter silica fibers to overcome some limitations of previous methods of measuring chordae tendineae forces. Using FBG sensors, we created a force sensing neochord (FSN) that mimics the natural shape and movement of native chordae. FBG sensors reflect a specific wavelength of light depending on the spatial period of gratings. When force is applied, the gratings move relative to one another, shifting the wavelength of reflected light. This shift is directly proportional to force applied. The FBG sensors were housed in a protective sheath fashioned from a 0.025 in. flat coil, and attached to the chordae using polytetrafluoroethylene suture. The function of the force sensing neochordae was validated in a three dimensional (3D) printed left heart simulator, which demonstrated that FBG sensors provide highly sensitive force measurements of mitral valve chordae at a temporal resolution of 1000 Hz. As ventricular pressures increased, such as in hypertension, chordae forces also increased. Overall, FBG sensors are a viable, durable, and high fidelity sensing technology that can be effectively used to measure mitral valve chordae forces and overcome some limitations of other such technologies.", "author_names": [ "Michael J Paulsen", "Jung Hwa Bae", "Annabel M Imbrie-Moore", "Hanjay Wang", "Camille E Hironaka", "Justin M Farry", "Haley J Lucian", "Akshara D Thakore", "Mark R Cutkosky", "Y Joseph Woo" ], "corpus_id": 195762129, "doc_id": "195762129", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Development and Ex Vivo Validation of Novel Force Sensing Neochordae for Measuring Chordae Tendineae Tension in the Mitral Valve Apparatus Using Optical Fibers With Embedded Bragg Gratings", "venue": "Journal of biomechanical engineering", "year": 2019 } ]

[ { "abstract": "Wide bandgap semiconductors have become the most attractive materials in optoelectronics in the last decade. Their wide bandgap and intrinsic properties have advanced the development of reliable photodetectors to selectively detect short wavelengths (i.e. ultraviolet, UV) in high temperature regions (up to 300degC) The main driver for the development of high temperature UV detection instrumentation is in situ monitoring of hostile environments and processes found within industrial, automotive, aerospace, and energy production systems that emit UV signatures. In this review, a summary of the optical performance (in terms of photocurrent to dark current ratio, responsivity, quantum efficiency, and response time) and uncooled, high temperature characterization of III nitride, SiC, and other wide bandgap semiconductor UV photodetectors is presented.", "author_names": [ "Ruth A Miller", "Hongyun So", "Thomas Heuser", "Debbie G Senesky" ], "corpus_id": 119362092, "doc_id": "119362092", "n_citations": 7, "n_key_citations": 0, "score": 1, "title": "High temperature Ultraviolet Photodetectors: A Review", "venue": "", "year": 2018 }, { "abstract": "In recent years, solar blind ultraviolet (UV) photodetectors have attracted significant attention from researchers in the field of semiconductor devices due to their indispensable properties in the fields of high temperature event monitoring, anti terrorism, security and ad hoc network communication. As an important member of the third generation semiconductors, b Ga2O3 is considered to be one of the most promising candidates for solar blind UV detectors due to its ultra wide band gap ~4.9 eV) economic efficiency, high radiation resistance and excellent chemical and thermal stability. Herein, we provide a comprehensive review on Ga2O3 based solar blind UV photodetectors, with a detailed introduction of the developmental process of material growth methods and device manufacturing in the past decade. We classify the currently reported Ga2O3 based solar blind UV photodetectors (mainly including photoconductive detectors, heterogeneous PN junction detectors and Schottky junction detectors) and summarize their respective superiorities and potentials for improvement. Finally, considering the actual application requirements, we put forward some meaningful suggestions, including energy band engineering and homogeneous epitaxy, for the future development of Ga2O3 material growth and device manufacturing.", "author_names": [ "Jingjing Xu", "Wei Zheng", "Feng Huang" ], "corpus_id": 197629589, "doc_id": "197629589", "n_citations": 89, "n_key_citations": 1, "score": 0, "title": "Gallium oxide solar blind ultraviolet photodetectors: a review", "venue": "", "year": 2019 }, { "abstract": "Ultraviolet (UV) photodetectors have drawn extensive attention owing to their applications in industrial, environmental and even biological fields. Compared to UV enhanced Si photodetectors, a new generation of wide bandgap semiconductors, such as (Al, In) GaN, diamond, and SiC, have the advantages of high responsivity, high thermal stability, robust radiation hardness and high response speed. On the other hand, one dimensional (1D) nanostructure semiconductors with a wide bandgap, such as b Ga2O3, GaN, ZnO, or other metal oxide nanostructures, also show their potential for high efficiency UV photodetection. In some cases such as flame detection, high temperature thermally stable detectors with high performance are required. This article provides a comprehensive review on the state of the art research activities in the UV photodetection field, including not only semiconductor thin films, but also 1D nanostructured materials, which are attracting more and more attention in the detection field. A special focus is given on the thermal stability of the developed devices, which is one of the key characteristics for the real applications.", "author_names": [ "Liwen Sang", "Meiyong Liao", "Masatomo Sumiya" ], "corpus_id": 17101427, "doc_id": "17101427", "n_citations": 475, "n_key_citations": 3, "score": 0, "title": "A Comprehensive Review of Semiconductor Ultraviolet Photodetectors: From Thin Film to One Dimensional Nanostructures", "venue": "Sensors", "year": 2013 }, { "abstract": "The objective of this chapter is to provide a concise review of the growth, characterization and properties of the nanorods and nanowires in two nitrides systems: the group III nitrides (specifically, AlN, GaN, InN and ternary Ga In N) and group IV nitrides (Si3N4 and ternary Si C N) During the last three decades, tremendous efforts have been devoted to the physics, chemistry and synthesis of GaN and related materials. The wurtzite polytypes of AlN, GaN and InN form a nearly continuous alloy system with direct band gaps between 1.9 and 6.2 eV, therefore, suitable for optoelectronic devices that are active at wavelengths ranging from the green well into the ultraviolet. In fact, all primary and mixed colors can be obtained by using nitride emitters as pumps. Progress in III nitride based devices has been made at an astonishing rate in the last decade [1] Besides the applications of III nitrides in light emitting diodes and laser diodes, high speed field effect transistors, ultraviolet photodetectors and high temperature electronic devices have been demonstrated [2 4] Furthermore, GaN is also chemically inert and radiation resistant and has been considered as a stable photocatalyst in photo electrochemical fuel cells [5] while InN/Si tandem cells have been proposed for high efficiency solar cells [6, 7] Of equal importance to just being an active component of the nitride optoelectronic devices, AlN has also attracted extensive interest for applications as electrical packaging material due to its high thermal conductivity and low coefficient of thermal expansion that closely matches that of silicon, and as components in structural composites owing to its excellent mechanical strength and chemical stability [8]", "author_names": [ "Li-Chyong Chen", "Kuei-Hsien Chen", "Chia-Chun Chen" ], "corpus_id": 179021574, "doc_id": "179021574", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Group III and Group IV Nitride Nanorods and Nanowires", "venue": "", "year": 2003 }, { "abstract": "The III V GaN based materials are being comprehensively investigated recently for its potential as ultraviolet photodetectors as well as light emitting devices,high temperature and high power electronic devices.Low resistance ohmic contacts are essential for improving the electrical and optical performance of GaN based devices.Low resistance contacts to p GaN are difficult to fabricate in part due to the low doping and hole ionization.Development of stable ohmic contacts on p GaN continues to be a challenge.By summering and analyzing of related papers published on English periodicals in recent years,this review focuses on the developments in improved p GaN processes and the current state of the art in contact performance.", "author_names": [ "Tang Li-bin" ], "corpus_id": 137724037, "doc_id": "137724037", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Developments of Ohmic Contacts of p Type GaN devices", "venue": "", "year": 2009 }, { "abstract": "We report fully aerosol jet printed ultraviolet photodetectors based on zinc oxide nanocrystal networks having a porous morphology. The developed photodetectors exhibit selective optical photoresponse in the ultraviolet spectrum at wavelengths ranging from 250 nm up to 400 nm. These devices show a high ON/OFF ratio of ~106 and short response times. The characteristic time constants for the rise and fall edges were measured to be ~0.4 and ~1.3 s, respectively. In this work, we propose a direct approach for aerosol jet printing of presynthesized nanocrystals to overcome the limitations of high post annealing temperatures and tedious fabrication methods to obtain high aspect ratio nanostructures. The high performance characteristics of these devices are attributed to Schottky barrier modification under the influence of oxygen, which is enhanced by the porosity of the semiconductor material. The random orientation of the crystals aids the formation of air traps in the network, thereby enhancing the surface ar.", "author_names": [ "Anubha A Gupta", "Shivaram Arunachalam", "Sylvain G Cloutier", "Ricardo Izquierdo" ], "corpus_id": 125120702, "doc_id": "125120702", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Fully aerosol jet printed, high performance nanoporous ZnO ultraviolet photodetectors", "venue": "", "year": 2018 }, { "abstract": "Ultraviolet (UV) photodetectors (PDs) as pivotal elements in modern optoelectronic devices, have attracted increasing research interest in recent years because of their wide applications both in civil and military fields such as confidential space communication, flame detection, imaging, and missile warning systems. Gallium oxide is a desirable candidate for deep UV photodetection due to its suitable ultrawide bandgap 4.5 to 4.9 eV) without the necessity of alloying process. It is reported that crystalline gallium oxide has five phases (a, b, g, d and e) and b phase is the most stable. Many kinds of crystalline gallium oxide UV PDs including bulk, thin films, and nanostructures have been demonstrated and summarized in several review articles recently. According to common understanding of semiconductors, properties of crystalline materials with limited defects are usually superior compared with their amorphous counterparts. For example, the performance of solar cells or transistors using crystalline Si is better than amorphous ones because the carrier mobility of crystalline Si is about 200 cm V 1 s which is much higher than the value of amorphous Si 1 cm V 1 s However, things have been changed in 2004, since the first report of high performance flexible thin film transistors (TFTs) based on amorphous InGaZnO (a IGZO) a transparent amorphous oxide semiconductor (TAOS) with electron mobility as high as 10 cm V 1 s From then on, TAOS TFTs as well as the fundamental material science have been extensively investigated and now they are being used in commercial large area flat panel displays. According to previous researches related with a IGZO, Ga element is a necessary stabilizer in the amorphous structure since gallium oxide will not crystallize unless the substrate temperature is higher enough, whereas indium oxide and zinc oxide tend to crystallize readily even at room temperature (RT) It indicates amorphous gallium oxide (a GaOx) could be realized more easily compared with indium oxide and zinc oxide. As a matter of fact, a GaOx has also attracted a great deal of attention due to its wide bandgap and high breakdown field strength. At the earlier stage, a GaOx thin films were mainly used as a dielectric layer or a passivation layer in microelectronic devices and solar cells. In 2017, three groups reported solar blind UV PDs using a GaOx thin films almost simultaneously. It is quite interesting that the performance of UV PD using a GaOx is comparable or even better than its crystalline counterpart. Except for UV PDs, a GaOx materials also have extensive applications in areas of solar cells, phosphors, resistance random access memories (RRAMs) gas sensors, and radiation detectors. These versatile applications together with the fact that scalable a GaOx can be easily prepared on almost any substrates make it appealing for flexible electronics and giant microelectronics. Great attention has been paid to this cost effective material, evidenced by the increased number of publications retrieved with the key word of \"amorphous Ga2O3,\" as shown in Figure 1. To further understand the material properties of a GaOx and construct superior UV PDs, it is necessary to summarize the progresses on a GaOx materials and devices. In this Review, we will Dr. H. Liang, Z. Han, Prof. Z. Mei Songshan Lake Materials Laboratory Dongguan, Guangdong 523808, China E mail: hlliang@iphy.ac.cn; zxmei@iphy.ac.cn Dr. H. Liang, Z. Han, Prof. Z. Mei Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190, China Z. Han School of Physical Sciences University of Chinese Academy of Sciences Beijing 100049, China", "author_names": [ "Huili Liang", "Zuyin Han", "Zengxia Mei" ], "corpus_id": 224998347, "doc_id": "224998347", "n_citations": 2, "n_key_citations": 1, "score": 0, "title": "Recent Progress of Deep Ultraviolet Photodetectors using Amorphous Gallium Oxide Thin Films", "venue": "physica status solidi (a)", "year": 2020 }, { "abstract": "Quantum dot infrared photodetectors (QDIPs) are positioned to become an important technology in the field of infrared (IR) detection, particularly for high temperature, low cost, high yield detector arrays required for military applications. High operating temperature (150 K) photodetectors reduce the cost of IR imaging systems by enabling cryogenic dewars and Stirling cooling systems to be replaced by thermo electric coolers. QDIPs are well suited for detecting mid IR light at elevated temperatures, an application that could prove to be the next commercial market for quantum dots. While quantum dot epitaxial growth and intraband absorption of IR radiation are well established, quantum dot non uniformity remains as a significant challenge. Nonetheless, state of the art mid IR detection at 150 K has been demonstrated using 70 layer InAs/GaAs QDIPs, and QDIP focal plane arrays are approaching performance comparable to HgCdTe at 77 K. By addressing critical challenges inherent to epitaxial QD material systems (e.g. controlling dopant incorporation) exploring alternative QD systems (e.g. colloidal QDs) and using bandgap engineering to reduce dark current and enhance multi spectral detection (e.g. resonant tunneling QDIPs) the performance and applicability of QDIPs will continue to improve.", "author_names": [ "Adrienne D Stiff-Roberts" ], "corpus_id": 28522357, "doc_id": "28522357", "n_citations": 79, "n_key_citations": 1, "score": 0, "title": "Quantum dot infrared photodetectors: a review", "venue": "", "year": 2009 }, { "abstract": "This work demonstrates the high temperature operation of metal semiconductor metal (MSM) photodetectors (PDs) up to 450 degC using lightly Al doped epitaxial 4H SiC thin films. The responsivity of the PDs under 325 nm illumination is 0.0305 A/W at 20 V bias at room temperature. The photocurrentto dark current ratio of the SiC MSM PDs is as high as 1.3 x 10⁵ at 25 degC and is 0.62 at 450 degC. The rise/fall time of the PDs is increased slightly from 594 ms/684 ms to 684 ms/786 ms as the temperature increases from room temperature to 400 degC. These results support the use of 4H SiC PDs in extremely high temperature applications.", "author_names": [ "Wei-Cheng Lien", "Dung-Sheng Tsai", "Der-Hsien Lien", "Debbie G Senesky", "Hau He", "Albert P Pisano" ], "corpus_id": 6057336, "doc_id": "6057336", "n_citations": 45, "n_key_citations": 1, "score": 0, "title": "4H SiC Metal Semiconductor Metal Ultraviolet Photodetectors in Operation of 450 \\circ}\\hbox{C}", "venue": "IEEE Electron Device Letters", "year": 2012 }, { "abstract": "This work demonstrates the high temperature operation of metal semiconductor metal (MSM) photodetectors (PDs) up to 450 *C using lightly Al doped epitaxial 4H SiC thin films. The responsivity of the PDs under 325 nm illumination is 0.0305 A/W at 20 V bias at room temperature. The photocurrentto dark current ratio of the SiC MSM PDs is as high as 1.3 x 10 at 25 *C and is 0.62 at 450 *C. The rise/fall time of the PDs is increased slightly from 594 ms/684 ms to 684 ms/786 ms as the temperature increases from room temperature to 400 *C. These results support the use of 4H SiC PDs in extremely high temperature applications.", "author_names": [ "Wei-Cheng Lien", "Dung-Sheng Tsai", "Der-Hsien Lien", "Debbie G Senesky", "- Hau He", "Albert P Pisano" ], "corpus_id": 24835875, "doc_id": "24835875", "n_citations": 16, "n_key_citations": 4, "score": 0, "title": "SiC Metal Semiconductor Metal Ultraviolet Photodetectors in Operation of 450 C", "venue": "", "year": 2012 } ]

[ { "abstract": "Two dimensional materials are an emerging class of new materials with a wide range of electrical properties and potential practical applications. Although graphene is the most well studied two dimensional material, single layers of other materials, such as insulating BN (ref. 2) and semiconducting MoS2 (refs 3, 4) or WSe2 (refs 5, 6) are gaining increasing attention as promising gate insulators and channel materials for field effect transistors. Because monolayer MoS2 is a direct bandgap semiconductor due to quantum mechanical confinement, it could be suitable for applications in optoelectronic devices where the direct bandgap would allow a high absorption coefficient and efficient electron hole pair generation under photoexcitation. Here, we demonstrate ultrasensitive monolayer MoS2 phototransistors with improved device mobility and ON current. Our devices show a maximum external photoresponsivity of 880 A W( 1) at a wavelength of 561 nm and a photoresponse in the 400 680 nm range. With recent developments in large scale production techniques such as liquid scale exfoliation and chemical vapour deposition like growth, MoS2 shows important potential for applications in MoS2 based integrated optoelectronic circuits, light sensing, biomedical imaging, video recording and spectroscopy.", "author_names": [ "Oriol Lopez-Sanchez", "Dominik S Lembke", "M Kayci", "Aleksandra Radenovic", "Andras Kis" ], "corpus_id": 5435971, "doc_id": "5435971", "n_citations": 3092, "n_key_citations": 33, "score": 2, "title": "Ultrasensitive photodetectors based on monolayer MoS2.", "venue": "Nature nanotechnology", "year": 2013 }, { "abstract": "We studied the influence of different pre deposition surface treatments and contact materials on the photoresponse decay. We find that different surface cleaning treatments can be used to reduce the decay time. This can be explained by differences in resulting level of hydrophobicity of the functionalized SiO", "author_names": [ "Oriol Lopez-Sanchez", "Dominik S Lembke", "M Kayci", "Aleksandra Radenovic", "Andras Kis" ], "corpus_id": 138219925, "doc_id": "138219925", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Supplementary information for Ultrasensitive photodetectors based on monolayer MoS2", "venue": "", "year": 2013 }, { "abstract": "2D transition metal dichalcogenide (2D TMD) materials and their van der Waals heterostructures (vdWHs) have inspired worldwide efforts in the fields of electronics and optoelectronics. However, photodetectors based on 2D/2D vdWHs suffer from performance limitations due to the weak optical absorption of their atomically thin nature. In this work, taking advantage of an excellent light absorption coefficient, low temperature solution processability, and long charge carrier diffusion length, all inorganic halides perovskite CsPbI3 x Br x quantum dots are integrated with monolayer MoS2 for high performance and low cost photodetectors. A favorable energy band alignment facilitating interfacial photocarrier separation and efficient carrier injection into the MoS2 layer inside the 0D 2D mixed dimensional vdWHs are confirmed by a series of optical characterizations. Owing to the synergistic effect of the photogating mechanism and the modulation of Schottky barriers, the corresponding phototransistor exhibits a high photoresponsivity of 7.7 x 104 A W 1, a specific detectivity of 5.6 x 1011 Jones, and an external quantum efficiency exceeding 107% The demonstration of such 0D 2D mixed dimensional heterostructures proposed here would open up a wide realm of opportunities for designing low cost, flexible transparent, and high performance optoelectronics.", "author_names": [ "Hualin Wu", "Haonan Si", "Zihan Zhang", "Zhuo Kang", "Pingwei Wu", "Lixin Zhou", "Suicai Zhang", "Zheng Zhang", "Qingliang Liao", "Yue Zhang" ], "corpus_id": 56595185, "doc_id": "56595185", "n_citations": 77, "n_key_citations": 2, "score": 0, "title": "All Inorganic Perovskite Quantum Dot Monolayer MoS2 Mixed Dimensional van der Waals Heterostructure for Ultrasensitive Photodetector", "venue": "Advanced science", "year": 2018 }, { "abstract": "Abstract Photodetectors (PD) with high detectivity, high quantum efficiency and fast response are fundamental units to achieve sensors, imagers, and many others functional optoelectronics. Here we demonstrate high performance vertical stacked 2D MoS2/CuPc heterojunction based photodetectors with high sensitivity, high external quantum efficiency and ultrafast response time. The functional p type organic thin film of CuPc was thermally evaporated on n type two dimension (2D) MoS2 monolayer to create an ideal type II heterojunction interface, where ultrafast charge transfer (CT) occur in 16 ps, followed by effective exciton separation and charge collection. As a result, photoresponse time as fast as 436 ms has been obtained for 2D MoS2/CuPc PDs, as well as a profound responsivity of 3.0 x 10 3 A/W and a detectivity of 2.0 x 1010 Jones with a peak external quantum efficiency (EQE) of 483% This work suggests a feasible route to develop ultrasensitive visible light photodetector by 2D materials.", "author_names": [ "Z -H Xu", "L L Tang", "S W Zhang", "J Z Li", "B L Liu", "S C Zhao" ], "corpus_id": 225233763, "doc_id": "225233763", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "2D MoS2/CuPc heterojunction based highly sensitive photodetectors through ultrafast charge transfer", "venue": "", "year": 2020 }, { "abstract": "Two dimensional (2D) materials are a new type of materials under intense study because of their interesting physical properties and wide range of potential applications from nanoelectronics to sensing and photonics. Monolayers of semiconducting transition metal dichalcogenides MoS2 or WSe2 have been proposed as promising channel materials for field effect transistors. Their high mechanical flexibility, stability, and quality coupled with potentially inexpensive production methods offer potential advantages compared to organic and crystalline bulk semiconductors. Due to quantum mechanical confinement, the band gap in monolayer MoS2 is direct in nature, leading to a strong interaction with light that can be exploited for building phototransistors and ultrasensitive photodetectors. Here, we report on the realization of light emitting diodes based on vertical heterojunctions composed of n type monolayer MoS2 and p type silicon. Careful interface engineering allows us to realize diodes showing rectification and light emission from the entire surface of the heterojunction. Electroluminescence spectra show clear signs of direct excitons related to the optical transitions between the conduction and valence bands. Our p n diodes can also operate as solar cells, with typical external quantum efficiency exceeding 4% Our work opens up the way to more sophisticated optoelectronic devices such as lasers and heterostructure solar cells based on hybrids of 2D semiconductors and silicon.", "author_names": [ "Oriol Lopez-Sanchez", "Esther Alarcon Llado", "Volodymyr B Koman", "Anna Fontcuberta i Morral", "Aleksandra Radenovic", "Andras Kis" ], "corpus_id": 9970109, "doc_id": "9970109", "n_citations": 324, "n_key_citations": 5, "score": 0, "title": "Light Generation and Harvesting in a van der Waals Heterostructure", "venue": "ACS nano", "year": 2014 }, { "abstract": "Two dimensional (2D) transition metal dichalcogenides (TMDs) have been receiving tremendous attention because of their outstanding performance as nanoscale devices. Monolayer molybdenum disulfide (MoS2) is a very promising candidate for applications such as field effect transistors, chemical sensors and ultrasensitive photodetectors due to its adjustable direct band gap. It is known that structural defects, which can not be avoided during the fabrication of the material, influence drastically its optical and electronic properties[1,2] Most of the defects are due to a lack of Sulfur atoms (S defect) which have been identified as a primary reason for the observed low performance of MoS2 based photoelectric devices. However, the S defect can also be used in a positive manner, for example, to promote the hydrogen evolution reaction[3] and to vary the properties of the material for the adsorption of molecules[4] by changing the coordination number of Mo atoms.", "author_names": [ "K Wang", "Beate Paulus" ], "corpus_id": 209753466, "doc_id": "209753466", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "First principle investigation of functionalized transition metal dichalcogenides", "venue": "", "year": 2019 }, { "abstract": "Monolayer MoS2, a direct bandgap transition metal dichalcogenide (TMD) has attracted worldwide attention in electronics and optoelectronics. However, the performance of photodetectors based on monolayer MoS2 is restricted to a weak optical absorption, narrow absorption range, and persistent photoconductance. Herein, benefiting from an easy solution process, high light absorption coefficient, and wide absorption range, environment friendly CuInSe2 quantum dots (QDs) are hybridized with monolayer MoS2 for high performance broadband photodetectors. Owing to the favorable type II energy band alignment of MoS2/CuInSe2 QDs, the hybrid photodetector exhibits a broadband photoresponse from the ultraviolet to near infrared region, with an ultrahigh photoresponsivity of 74.8 A/W at 1064 nm, and compared with those of the pristine MoS2 device, the photoresponsivity and specific detectivity in the ultraviolet visible region were enhanced by about 30 and 20 times, respectively. Furthermore, the formed depletion region at the MoS2/CuInSe2 QDs interface can significantly increase the photoresponse speed, and the accumulated holes in the QD side induce a strong photogating effect to improve the photoresponsive characteristics of the hybrid photodetector. Our work opens up opportunities for fabricating high performance monolayer TMD based broadband photodetectors.", "author_names": [ "Tao Shen", "Feng Li", "Zhenyun Zhang", "Lei Xu", "Junjie Qi" ], "corpus_id": 227175101, "doc_id": "227175101", "n_citations": 5, "n_key_citations": 1, "score": 0, "title": "High Performance Broadband Photodetector Based on Monolayer MoS2 Hybridized with Environment Friendly CuInSe2 Quantum Dots.", "venue": "ACS applied materials interfaces", "year": 2020 }, { "abstract": "Field effect transistor (FET) biosensors based on low dimensional materials present the advantages of low cost, high speed, small size, and excellent compatibility with integrated circuits (ICs) In this work, we fabricated highly sensitive FET based DNA biosensors based on chemical vapor deposition (CVD) grown monolayer MoS2 films in batches and explored their application in noninvasive prenatal testing (NIPT) for trisomy 21 syndrome. Specifically, MoS2 was functionalized with gold nanoparticles (Au NPs) of an optimized size and at an ideal density, and then, probe DNAs for the specific capture of target DNAs were immobilized on the nanoparticles. The fabricated FET biosensors are able to reliably detect target DNA fragments (chromosome 21 or 13) with a detection limit below 100 aM, a high response up to 240% and a high specificity, which satisfy the requirement for the screening of Down syndrome. In addition, a real time test was conducted to show that the biosensor clearly responds to the target DNA at concentrations as low as 1 fM. Our approach shows the potential for detecting the over expression of chromosome 21 in the peripheral blood of pregnant women and achieving Down syndrome screening.", "author_names": [ "Jingxia Liu", "Xihua Chen", "Qinqin Wang", "Mengmeng Xiao", "Donglai Zhong", "Wei Sun", "Guangyu Zhang", "Zhiyong Zhang" ], "corpus_id": 73453946, "doc_id": "73453946", "n_citations": 60, "n_key_citations": 0, "score": 0, "title": "Ultrasensitive Monolayer MoS2 Field Effect Transistor Based DNA Sensors for Screening of Down Syndrome.", "venue": "Nano letters", "year": 2019 }, { "abstract": "Abstract Two dimensional layers of metal dichalcogenides have attracted much attention because of their ultrathin thickness and potential applications in electronics and optoelectronics. In this regard, we further explore the optoelectronic properties of monolayer MoS2 synthesized by chemical vapor deposition on sapphire substrate and contacted the Au electrode by lithographie method for applications in photodetectors. The device exhibits broadband photoresponse (UV Vis NIR) a lower subthreshold swing (0.5 V) higher detectivity (1010 Jones) and superior responsivity (0.0084 A/W) We believe that this work provides important scientific insights for photoelectric response properties of emerging atomically layered 2D materials for optoelectronic applications.", "author_names": [ "Yong Heng Zhou", "Heishoku An", "Cheng Gao", "Zhaoqiang Zheng", "Bing Wang" ], "corpus_id": 104752854, "doc_id": "104752854", "n_citations": 19, "n_key_citations": 0, "score": 0, "title": "UV Vis NIR photodetector based on monolayer MoS2", "venue": "Materials Letters", "year": 2019 }, { "abstract": "", "author_names": [ "Louwen Zhang", "Shaoli Shen", "Man Li", "Luying Li", "Jibin Zhang", "Lianwei Fan", "Feng Cheng", "Chen Li", "Mengqin Zhu", "Zhe Kang", "Jun Su", "Tianyou Zhai", "Yihua Gao" ], "corpus_id": 108527609, "doc_id": "108527609", "n_citations": 19, "n_key_citations": 0, "score": 0, "title": "Strategies for Air Stable and Tunable Monolayer MoS 2 Based Hybrid Photodetectors with High Performance by Regulating the Fully Inorganic Trihalide Perovskite Nanocrystals", "venue": "Advanced Optical Materials", "year": 2019 } ]

[ { "abstract": "As metal oxide semiconductor (MOS) based devices and circuits faces glowingly physical barriers down the popularity and some constraints such as limitation of scaling, short channel effect, and hot carrier effect, so innovative technique for the synthesis of circuits in Nano scale have been developed to raise the popularity of computing. These Nano computing techniques have shown good performance in term of speed, area and integration density. This article is devoted to the robust architecture of dual rail checker using the co planar technique in QCA Designer tool. These designs are of concern to modern testing approach. These circuits are also included a modern approach for physical implementation such as Quantum Dot cellular automata. The main concern of this article is on the synthesis of nano computing testing circuit in QCA. The interest of this article is not only synthesis aspects it covers the physical implementation aspect also. Dual rail checker is an inherent module of the testing digital logic circuit. High device density happens to be an important factor in the synthesis of the Dual rail checker. The article proposed a robust architecture of Dual rail checker using QCA Technology, which consumes a less number of quantum cell and latency. To tackle the fault during the computing, we have synthesis a novel dual rail checker design for 4 dot, 2 electron based QCA architecture via co planar technique.", "author_names": [ "D Kiran Kumar", "Vijay Shankar", "K Vittal" ], "corpus_id": 211121041, "doc_id": "211121041", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "A New Robust Design of Dual Rail Checker in QCA Technology, Capable of Testing of Digital Electronics Circuit", "venue": "2019 International Conference on Smart Systems and Inventive Technology (ICSSIT)", "year": 2019 }, { "abstract": "\"In contemporary electronics 80% of a chip may perform digital functions but the 20% of analog functions may take 80% of the development time.\" [1] Aggravating this, the demands on analog design is increasing with rapid technology scaling. Most designs have moved away from analog to digital domains, where possible, however, interacting with the environment will always require analog to digital data conversion. Adding to this problem, the number of sensors used in consumer and industry related products are rapidly increasing. Designers of ADCs are dealing with this problem in several ways, the most important is the migration towards digital designs and time domain techniques. Time to Digital Converters (TDC) are becoming increasingly popular for robust signal processing. Biological neurons make use of spikes, which carry spike timing information and will not be affected by the problems related to technology scaling. Neuromorphic ADCs still remain exotic with few implementations in sub micron technologies Table 2.7. Even among these few designs, the strengths of biological neurons are rarely exploited. From a previous work [2] LUCOS, a high dynamic range image sensor, the efficiency of spike processing has been validated. The ideas from this work can be generalized to make a highly effective sensor signal conditioning system, which carries the promise to be robust to technology scaling. The goal of this work is to create a novel spiking neural ADC as a novel form of a Multi Sensor Signal Conditioning and Conversion system, which Will be able to interface with or be a part of a System on Chip with traditional analog or advanced digital components. Will have a graceful degradation. Will be robust to noise and jitter related problems. Will be able to learn and adapt to static errors and dynamic errors. Will be capable of self repair, self monitoring and self calibration Sensory systems in humans and other animals analyze the environment using several techniques. These techniques have been evolved and perfected to help the animal sur vive. Different animals specialize in different sense organs, however, the peripheral neural network architectures remain similar among various animal species with few ex ceptions. While there are many biological sensing techniques present, most popularly used engineering techniques are based on intensity detection, frequency detection, and edge detection. These techniques are used with traditional analog processing (e.g. colorvi sensors using filters) and with biological techniques (e.g. LUCOS chip [2] The local ization capability of animals has never been fully utilized. One of the most important capabilities for animals, vertebrates or invertebrates, is the capability for localization. The object of localization can be predator, prey, sources of water, or food. Since these are basic necessities for survival, they evolve much faster due to the survival of the fittest. In fact, localization capabilities, even if the sensors are different, have convergently evolved to have same processing methods (coincidence detection) in their peripheral neurons (for e.g. forked tongue of a snake, antennae of a cockroach, acoustic localization in fishes and mammals) This convergent evolution increases the validity of the technique. In this work, localization concepts based on acoustic localization and tropotaxis are investigated and employed for creation of novel ADCs. Unlike intensity and frequency detection, which are not linear (for e.g. eyes saturate in bright light, loose color perception in low light) localization is inherently linear. This is mainly because the accurate localization of predator or prey can be the difference between life and death for an animal. Figure 1 visually explains the ADC concept proposed in this work. This has two parts. (1) Sensor to Spike(time) Conversion (SSC) (2) Spike(time) to Digital Conversion(SDC) Both of the structures have been designed with models of biological neurons. The combination of these two structures is called SSDC. To efficiently implement the proposed concept, a comparison of several biological neural models is made and two models are shortlisted. Various synapse structures are also studied. From this study, Leaky Integrate and Fire neuron (LIF) is chosen since it fulfills all the requirements of the proposed structure. The analog neuron and synapse designs from Indiveri et. al. [3] [4] were taken, and simulations were conducted using cadence and the behavioral equivalence with biological counterpart was checked. The LIF neuron had features, that were not required for the proposed approach. A simple LIF neuron stripped of these features and was designed to be as fast as allowed by the technology. The SDC was designed with the neural building blocks and the delays were designed using buffer chains. This SDC converts incoming Time Interval Code (TIC) to sparse place coding using coincidence detection. Coincidence detection is a property of spiking neurons, which is a time domain equivalent of a Gaussian Kernel. The SDC is designed to have an online reconfigurable Gaussian kernel width, weight, threshold, and refractory period. The advantage of sparse place codes, which contain rank order coding wasvii Figure 1: ADC as a localization problem (right) Jeffress model of sound localization visualized (left) The values t 1 and t 2 indicate the time taken from the source to s1 and s2 respectively. described in our work [5] A time based winner take all circuit with memory was created based on a previous work [6] for reading out of sparse place codes asynchronously. The SSC was also initially designed with the same building blocks. Additionally, a differential synapse was designed for better SSC. The sensor element considered wasviii a Wheatstone full bridge AMR sensor AFF755 from Sensitec GmbH. A reconfigurable version of the synapse was also designed for a more generic sensor interface. The first prototype chip SSDCa was designed with 257 modules of coincidence detectors realizing the SDC and the SSC. Since the spike times are the most important information, the spikes can be treated as digital pulses. This provides the capability for digital communication between analog modules. This creates a lot of freedom for use of digital processing between the discussed analog modules. This advantage is fully exploited in the design of SSDCa. Three SSC modules are multiplexed to the SDC. These SSC modules also provide outputs from the chip simultaneously. A rising edge detecting fixed pulse width generation circuit is used to create pulses that are best suited for efficient performance of the SDC. The delay lines are made reconfigurable to increase robustness and modify the span of the SDC. The readout technique used in the first prototype is a relatively slow but safe shift register. It is used to analyze the characteristics of the core work. This will be replaced by faster alternatives discussed in the work. The area of the chip is 8.5 mm 2 It has a sampling rate from DC to 150 kHz. It has a resolution from 8 bit to 13 bit. It has 28,200 transistors on the chip. It has been designed in 350 nm CMOS technology from ams. The chip has been manufactured and tested with a sampling rate of 10 kHz and a theoretical resolution of 8 bits. However, due to the limitations of our Time Interval Generator, we are able to confirm for only 4 bits of resolution. The key novel contributions of this work are Neuromorphic implementation of AD conversion as a localization problem based on sound localization and tropotaxis concepts found in nature. Coincidence detection with sparse place coding to enhance resolution. Graceful degradation without redundant elements, inherent robustness to noise, which helps in scaling of technologies Amenable to local adaptation and self x features. Conceptual goals have all been fulfilled, with the exception of adaptation. The feasibility for local adaptation has been shown with promising results and further investigation is required for future work. This thesis work acts as a baseline, paving the way for R&D in a new direction. The chip design has used 350 nm ams hitkit as a vehicle to prove the functionality of the core concept. The concept can be easily ported to present aggressively scaled technologies and future technologies.", "author_names": [ "K N Subramanyam", "Aniruddha Chandra" ], "corpus_id": 116785064, "doc_id": "116785064", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Conception and First Implementation of Novel Sensory Signal Conditioning and Digital Conversion Electronics Based on Spiking Neuron Ensembles for Inherently Robust Processing in Aggressively Scaled Integration Technologies", "venue": "", "year": 2017 }, { "abstract": "Quantum dot cellular automata (QCA) is the beginning of novel technology and is capable of an appropriate substitute for orthodox semiconductor transistor technology in the nanoscale extent. A competent adder and subtractor circuit can perform a substantial function in devising arithmetic circuits. The future age of digital techniques will exercise QCA as preferred nanotechnology. The QCA computational procedures will be simplified with an effective full adder and subtractor circuit. The deficiencies of variations and assembly still endure as a setback in QCA based outlines, and being capricious and inclined to error is the limitation of these circuits. In this study, a new full adder and subtractor design using unique 3 input XOR gate with cells redundancy is proposed. This designs can be utilized to form different expedient QCA layouts. The structures are formed in a single layer deprived of cross wiring. Besides, this study is directed to the analysis of the functionality and energy depletion possessions of the outlined full adder and subtractor circuits. For the first time, QCADesigner Energy (QD E) version 2.0.3 tool is utilized to find the overall depleted energy. The attained effects with QCADesigner have verified that the outlined design has enhanced functioning in terms of intricacy, extent, and latency in contrast to the earlier designs. Moreover, the redundant form of full adder and subtractor has uncomplicated and robust arrangement competing typical styles.", "author_names": [ "", "Ali Newaz Bahar" ], "corpus_id": 55672151, "doc_id": "55672151", "n_citations": 18, "n_key_citations": 1, "score": 0, "title": "An Architecture of 2 Dimensional 4 Dot 2 Electron QCA Full Adder and Subtractor with Energy Dissipation Study", "venue": "", "year": 2018 }, { "abstract": "In today's budgetary environment, there is significant interest within the National Aeronautics and Space Administration (NASA) to enable small robotic science missions that can be executed faster and cheaper than previous larger missions. To help achieve this, focus has shifted from using exclusively radiationtolerant or radiation hardened parts to using more commercial off the shelf (COTS) components for NASA small satellite missions that can last at least one year in orbit. However, there are some portions of a spacecraft's avionics, such as the Command and Data Handling (C&DH) subsystem and the Power System Electronics (PSE) that need to have a higher level of reliability that goes beyond what is attainable with currently available COTS parts. While there are a number of COTS components that can withstand a total ionizing dose (TID) of tens or hundreds of kilorads, there is still a great deal of concern about tolerance to and mitigation of single event effects (SEE) The Goddard Modular SmallSat Architecture (GMSA) is an initiative at NASA Goddard Space Flight Center (GSFC) to address these radiation tolerance and reliability issues, while also minimizing development cost and schedule. The goal of GMSA is to develop a highly reliable, modular, flexible, and extensible small satellite implementation approach that can incorporate spacecraft components and subsystems that either developed within NASA or procured from industry. This paper provides details of a new technology development effort that will implement a miniaturized C&DH and PSE within a 6U (10cm x 20cm x 30cm) satellite. This effort has a goal of enabling ambitious science missions using SmallSats that can operate for longer durations in harsher environments than can be achieved with existing SmallSat technologies. The GMSA PSE uses Direct Energy Transfer (DET) topology with the battery connected directly to the bus. The shunt control technique is a linear sequential full shunt which provides a simple solar array interface and can support both 3 axis stabilized and spinner satellites. The PSE includes all the circuits needed to perform telemetry and command functions using an I2C interface with the C&DH. In addition, the PSE has been designed, tested, and verified to meet launcher vehicle safety requirement. The GMSA C&DH functionality is implemented as a SmallSat Common Electronics Board (SCEB) and an Adapter Board. The SCEB can be configured to implement a variety of serial communication interfaces including RS 422, I2C, SPI, and SpaceWire. There are also a number of available general purpose input/output (GPIO) signals. The SCEB includes a reprogrammable FPGA that contains a soft core processor running flight software (FSW) based on NASA GSFC's Core Flight System (cFS) Lastly, the SCEB interfaces with an Adapter Board that contains the analog circuitry that converts temperature, voltage, and current data collected from multiple points within 6U satellite to a digital format that can be processed, stored, and downlinked using the front end communication interface.", "author_names": [ "Hanson Cao Nguyen", "James Fraction" ], "corpus_id": 64589488, "doc_id": "64589488", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Robust, Radiation Tolerant Command and Data Handling and Power System Electronics for SmallSats", "venue": "", "year": 2018 }, { "abstract": "Binary Decision Diagrams (BDDs) play an important role in the synthesis, verification, and testing of VLSI circuits and other applications like security, shape analysis of geometric objects etc. In this work, we have reported a new BDD based approach for the synthesis of dual rail adiabatic MUX circuits, which works much better in low frequency application. For high frequency application the best dual rail logic for BDD based synthesis is Dynamic Cascode Voltage Switch with Pass Gate (DCVSPG) logic, which we have used as library cell and made logic synthesis more optimized in area and power. As technology mapping has become significant in reducing chip area in terms of number of logical block we have also introduced an efficient mapping algorithm which can map single rail logic cells like LEAP (Lean Integration with Pass Transistors) cells from BDD for better optimization in terms of area, power and delay. Testing of such VLSI circuits is another challenge for chip manufacturer. ATPG (Automatic Test Pattern Generator) is ruling this sector for many years. But circuit realized from special type of graph like BDD an alternative to ATPG can be employed to find test vectors for optimum fault coverage. In this work, we consider the open problem of generating in polynomial time, the exact minimum set of test vectors for detecting all single stuck at faults in such a BDD based circuit synthesized with multiplexers. This procedure not only generates the optimal test set in polynomial time, but also obviates the need of employing an ATPG and a fault simulator. We have also reported a simple algorithm for determining the maximum independent set of edges of a BDD that has got direct relation for finding optimal stuck at fault test set in a BDD based circuit. We have also considered how to detect stuck at faults when circuit is ON. For this we have reported a BDD based methodology for designing low power and low area online testing (OLT) device which can efficiently detect all the stuck at faults in smaller cycle time. Next, in this work, we have designed a BDD based asynchronous adder that obviates the need of complex ASIC flow. Also, the design takes much less area and power compared to the design with other standard library cell. We have also shown that a slight modification of such circuit can be made secure from external attack like side channel attack (SCA) For both the designs we have achieved a significant amount of reduction in area and power compared to the contemporary designs. We have successfully taped out these chips using TSMC fabrication unit. Another application of BDD on security has been proposed in the area of internet firewall design. We have implemented a BDD based packet filter firewall which is robust and more efficient than the existing list based packet filter firewall system.", "author_names": [ "Ajit Pal", "Bhargab B Bhattacharya", "Gopal Paul" ], "corpus_id": 63922605, "doc_id": "63922605", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Studies in logic synthesis, testing, and security issues of digital circuits based on binary decision diagrams", "venue": "", "year": 2011 }, { "abstract": "With the scaling of CMOS technology slowly coming to a halt due to quantum mechanics effects progressively eroding its performance as transistor dimensions shrink, new and experimental technologies for digital circuits are being explored and prototyped with increased effort. Design tools for such technologies have been created for these purposes and their development and refinement is now more critical than ever. ToPoliNano, developed by the VLSI group of the Polytechnic University of Turin, is one such tool, dedicated to the design and simulation of digital circuits built with nanomagnetic technologies based on Magnetic QCA. A robust EDA tool by itself with an easy to use GUI, it only missed, with regards to the more established professional software available to circuit designers that work with CMOS technology, the flexibility of a dual GUI/command line offering. The aim of this Master's thesis consisted therefore of expanding the capabilities of ToPoliNano by equipping it with a text based workflow, allowing users to access the program's powerful features by means of text commands and automation scripts. In order to bring the aforementioned text based workflow to life, three software modules have been developed in succession as part of the thesis, each complementing the others: a command line interface (CLI) able to tokenize, parse and interpret a variety of text commands mapped to the functionalities of ToPoliNano (for example: layout generation, layout import/export, circuit simulation, etc. a new general purpose preprocessor capable of processing variables, loops and conditional statements, which unlocks the possibility of writing complex scripts that go beyond a simple list of commands; a console mode (loaded into terminal) referred to as no GUI mode, which directly interfaces the user with the CLI (and, by extension, to ToPoliNano) without the need to load the GUI (which also allows the user to interact with the CLI but via widgets included in the graphical interface) As the final part of the thesis, a comprehensive user manual was written illustrating the purpose of each supported text command, the structure of the command line workflow and the advanced scripting features available to the user, including a collection of example scripts to help the user gain a complete, in depth understanding of the new instruments at their disposal for designing digital circuits.", "author_names": [ "Francesco Russo" ], "corpus_id": 201887894, "doc_id": "201887894", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "CAD Tools for Emerging Nanotechnologies", "venue": "", "year": 2019 }, { "abstract": "Abstract In this paper we will present the design status of the Digital Front End Electronic system (DFEE) that will be used for the EUSO photon detector. The DFEE is able to count the single photoelectrons coming form the detector for a given time period, store the numbers in a memory buffer and read them out after a trigger, using a serial communication line. Because of space, mass and power consumption constraints, the system will be implemented in an ASIC using a deep submicron technology. The actual design follows the original ideas of the system, though adding several new functionalities. A fully functional prototype chip has been submitted for fabrication in fall 2002. Extensive tests will be performed on it both with bench instrumentations and with the real sensor (the multi anode photomultiplier Hamamatsu R7600 M64) expecting significant results by early Summer 2003. Future work is needed to convert the design into a more robust RAD hard technology, suitable for space applications and to include in the final die an additional circuit used to optimize the performances at high photons rates: the Analog Front End Electronics (AFEE) Moreover the base board used to house the multi anode photomultipliers is presented: it is the back bone of the microcell and will be the basic block used to build up the EUSO focal surface.", "author_names": [ "Paolo Musico", "Marco Pallavicini", "Alessandro Petrolini", "Fernando Angulo Pratolongo" ], "corpus_id": 111302585, "doc_id": "111302585", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Digital front end electronics design for the EUSO photon detector", "venue": "", "year": 2003 }, { "abstract": "Quantum Cellular Automata (QCA) has been widely used to digital circuits and systems in recent years. QCA technology is a promising alternative to CMOS technology, which offers a novel electronics paradigm for information processing and communication. It has the attractive features such as faster speed, higher scale integration, smaller size and lower power consumption than transistor technology. Previously, adder designs based on conventional designs were examined for implementation by QCA technology. A briefness cell is used as the basic element, which is a building block to construct gates and wires. In this paper, we propose two kinds of new adder designs based on QCA. One is full adder, and the other is carry look ahead half adder. The simulation results show that the adder designs we proposed are more robust and reliable compared with previous works in the aspects of complexity, area, crossing and delay.", "author_names": [ "Airong Nie", "Ping Fan" ], "corpus_id": 64629705, "doc_id": "64629705", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Novel Adder Design Using Quantum Cellular Automata Implementation", "venue": "", "year": 2017 }, { "abstract": "Continuing increases in both the size and complexity of digital signal processing (DSP) systems places a considerable demand on the design engineer to develop hardware architectures capable of fulfilling the growing functional requirements expected of modem DSP devices. Automated circuit design techniques provide the design engineer with a tool to more effectively generate high performance signal processors capable of meeting demanding specifications. Evolvable hardware (El lW) is a relatively new approach to automated circuit design which utilises advances in reconfigurable hardware technology and the power of modem micro processors to generate circuits based on the principles of natural selection and evolution. This thesis investigates the suitability of software biased and hardware oriented programmable platforms, configured via EHW, and tailored for the automated design of high performance DSP circuits. Performance criteria such as timing, area and circuit robustness are considered. A number of benchmarked DSP circuits were initially considered. It was shown that by using larger functional logic macros as building blocks El lW is more successful at generating circuit solutions than if only gate primitives are used. In addition, the circuits generated are of comparable or better performance than equivalent circuits developed using a standard digital design methodology. Results also indicated that for more complex DSP functions to be generated, EHW platforms must use larger functional blocks, constrained for a specific application. Finite Impulse Response (FIR) filters were identified as the key function of many DSP applications, and the multiplication unit was targeted as the performance critical component. A novel Programmable Arithmetic Logic Unit (PALU) was therefore developed as a functional building block suitable for automated digital filter design using EHW. The PALU replaces coefficient multiplication with a series of bit shifts, additions and subtractions. Two distinct arrays of PALU were developed based on conventional FPGA and PLA re configurable hardware architectures. Results show that a PLA architecture with 2 levels of hierarchical interconnect and column based fixed tap outputs provides a platform most suited to automated filter design using the EHW technique. The PLA was also shown to be be robust to faults covering up to 25% of the array when configured using EHW. Declaration of originality I hereby declare that the research recorded in this thesis and the thesis itself was composed and originated entirely by myself in the Department of Electronics and Electrical Engineering at The University of Edinburgh.", "author_names": [ "Ben I Hounsell" ], "corpus_id": 58031385, "doc_id": "58031385", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Programmable architectures for the automated design of digital FIR filters using evolvable hardware", "venue": "", "year": 2001 }, { "abstract": "The latest phased array radar and communications systems being developed for Actively Electronically Scanned Array (AESA) 5G and Tactical communications are following trends of higher frequency operation and physical densification. With greater numbers of antenna elements, transmit/receive modules, antenna processors, and other analog/hybrid/digital beamforming modules in a single phased array antenna system, additional RF interconnect design considerations emerge. These new designs involve fitting a greater number of RF connectors and cable assemblies that also house more integrated PCBs that support analog, digital, and RF circuits. Reducing the size, weight, cost, and installation complexity of RF interconnects must also be considered. This article aims to educate engineers and industry professionals working with phased array antenna systems for radar and the new design considerations and solutions that help mitigate the challenges associated with building the next generation of phased array radar. Phased Array Radar Trends Phased array antennas, and subsequent radar and communication systems, benefit from the physics of electromagnetics, in that the size of optimized RF structures is inversely proportional to the frequency at which they operate. This means that antennas built for higher frequencies are smaller and otherwise more compact than antennas for lower frequency applications. In the case of multi element antennas, such as phased array antennas, this means that increasing the operating frequency has a dramatic impact on the size, weight, cost, and even power of these systems. There is a caveat, however, in that a variety of losses, such as RF loss and atmospheric attenuation, are also greater at higher frequencies. These additional losses can be compensated for by adding additional antenna elements in phased array radars. Moreover, incorporating active phase and amplitude control enables an operator or algorithm to precisely control the antenna pattern of a phased array antenna. In the case of AESA radars, jammers, and Tactical Communications, this ability is critical in avoiding harm to sensitive receivers, or more effectively controlling beam patterns to target enemy radar or friendly communications. This ability has given rise to a variety of actively controlled antenna techniques that allow for low probability of intercept/low probability of detection (LPI/LPD) Moreover, at higher frequencies, the beam width of an antenna becomes more narrow, enhancing the directivity over a comparable, but lower frequency, multi element antenna. These factors have given rise to the interest in using millimeter wave (mmWave) phased array antennas for radars, jammers, Tactical Communications, and upcoming mmWave 5G communications [1, 2, 3] Though the compact nature of mmWave antennas becomes attractive from a size, weight, power, and cost (SWAP C) perspective, the reduction in overall antenna size, alongside the dramatic Resources and References 1. https:/www.mwrf.com/defense/darpa launches millimeter wave program 2. https:/www.darpa.mil/program/millimeter wave digital arrays 3. https:/www.upi.com/Raytheon tapped by DARPA for high frequency digital communications research/3351541528087/ RF INTERCONNECT FOR THE NEXT GENERATION OF PHASED ARRAY RADAR AND COMMUNICATIONS belfuse.com/cinch increase in antenna elements, means that the associated RF interconnect must also be contained within these reduced size modules. High density RF interconnect, which still meet stringent MIL SPEC ruggedness requirements, are necessary to provide the interconnect between the growing diversity of transmit/receive (TR) modules, Antenna Processing Units (APUs) hybrid beamforming circuitry, and/or analog beamforming components. High quality RF interconnect that meet the SWAP C requirements of these new phased array antenna systems is essential during the prototyping, testing, and production phases, and are also key components of deployed phased array systems. With the intended use cases of mmWave 5G extending to industrial, automotive, and infrastructure applications, it is likely that many of the same ruggedization and reliability requirements used by military/aerospace markets will extend to mmWave 5G. Phased Array Radar Signal Chain A basic phased array antenna consists of RF interconnect, attenuators/amplifiers, phase shifters, and antenna elements. In this basic case, RF interconnect is needed to connect between the transmitter, receiver, circulator/isolator/ switch, attenuators/amplifier, phase shifter, and antenna elements. Another topology (that is becoming increasingly common) is the use of TR modules, which place the transmitter power amplifier (PA) and receiver low noise amplifier (LNA) in a module that is then connected through the same RF path to switches/circulators from the phase shifter to the antenna element. TR modules are used to enable the benefits of integration and modularity, further reducing the overall size of the antenna. This approach tends to require much smaller pitch and higher density RF interconnect than basic phased array antennas, as using larger RF interconnect negates many of the size and weight benefits of mmWave reduced element size. The next level of this integration is to use hybrid, or digital, beamforming phased array antenna topologies that allow for much more compact components, such as System on Chip (SoC) System in package (SiP) integrated RF frontend modules, APU ASICs, and other types of compact assemblies, modules, or ICs. Hybrid and digital beamforming enable much more compact phased array antennas and can employ high speed digital communications instead of RF communications between the modulation circuitry and the RF circuitry. In these cases, even tighter pitch and higher density RF interconnect are needed to provide connections between the high speed communication buses of the modems and the beamforming electronics. Though jammers and some lower frequency radars will require larger sized RF components and interconnect due to the power requirements of such systems, both Tactical Communications and mmWave 5G communications are likely to continue to greater levels of integration and densification. The need for this stems from reducing SWAP C parameters and enabling the deployment of massive numbers of mmWave base stations, which would otherwise be limited if the SWAP C parameters of the communication systems were comparable to radar and jammer systems. The densification of mmWave phased array antenna systems also brings into consideration the sensitivity of such a system to external and internal interference, especially when considering the high speed data lines and multitudes of low power mmWave RF interconnect inevitable in communication systems. Coaxial cable assemblies and interconnect are excellent at providing shielded communications with minimizing insertion loss and attenuation. This concept also applies to highly sophisticated radar, which uses many of the same modulation technologies (spread spectrum) as modern communications. Hence, there is, and will be, a growing need for a wide range of high density RF interconnect technologies, from ruggedized SMA cable assemblies to compact ultra miniature ganged connector modules. RF INTERCONNECT FOR THE NEXT GENERATION OF PHASED ARRAY RADAR AND COMMUNICATIONS Even with greater integration, RF interconnect is still needed for high speed digital signals and output to the antenna elements, though the interconnect will likely need to be denser. RF Interconnect Design Considerations for Phased Array Antenna Though radar, jamming, Tactical Communications, and mmWave 5G communications have very different end goals and deployment scenarios, many of the RF interconnect considerations are the same. The following sections are dedicated to discussing the top design considerations for mmWave phased array antenna systems and include application specific details and examples. Phase Stability and Phase Matched Coaxial Cable Assemblies The benefits of a phased array antenna are derived by the ability to precisely control the phase of the RF signal at the output of the antenna. This is only possible if the phase of the signal is stable and predictable throughout the phased array antenna system signal chain. There are two main RF interconnect considerations in this area. One is the phase stability of signals passing through a coaxial cable, based on environmental factors such as shock, vibration, flexure, warp, temperature, etc. Using \"phase stable\" coaxial cables helps to ensure that environmental influence is minimized. RF INTERCONNECT FOR THE NEXT GENERATION OF PHASED ARRAY RADAR AND COMMUNICATIONS belfuse.com/cinch The other consideration is the phase match between the coaxial cables used. Systematic phase error could be introduced by the coaxial cable production process, leading to even same length coaxial cables exhibiting variances in the phase response. Hence, using phase matched coaxial cables (which are cables ordered to have an incredibly similar phase response) can help to eliminate the concern of phase variances from RF interconnect and enhance predictability and performance of phased array antenna systems. Mechanically Robust Connections Military/aerospace manufacturers are required to use MIL SPEC coaxial cables, connectors, and assemblies, which must meet a minimum standard of ruggedness and reliability. These standards include resilience to damage from shock, vibration, thermal cycles, and environmental agents. Especially with highly sensitive phased array antenna systems operating at mmWave frequencies, mechanical reliability is essential for all mission critical RF communications, radar, and jamming. Even slight mechanical forces, if allowed to affect a phased array antenna system, could reduce overall system performance, produce hard to identify transient failures, or otherwise render the system inoperable. Many of these high r", "author_names": [ "" ], "corpus_id": 218477251, "doc_id": "218477251", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "RF Interconnect for the Next Generation of Phased Array Radar and Communications", "venue": "", "year": 2019 } ]

[ { "abstract": "Neural networks have proven effective for solving many difficult computational problems. Implementing complex neural networks in software is very computationally expensive. To explore the limits of information processing, it will be necessary to implement new hardware platforms with large numbers of neurons, each with a large number of connections to other neurons. Here we propose a hybrid semiconductor superconductor hardware platform for the implementation of neural networks and large scale neuromorphic computing. The platform combines semiconducting few photon light emitting diodes with superconducting nanowire single photon detectors to behave as spiking neurons. These processing units are connected via a network of optical waveguides, and variable weights of connection can be implemented using several approaches. The use of light as a signaling mechanism overcomes fanout and parasitic constraints on electrical signals while simultaneously introducing physical degrees of freedom which can be employed for computation. The use of supercurrents achieves the low power density necessary to scale to systems with enormous entropy. The proposed processing units can operate at speeds of at least $20$ MHz with fully asynchronous activity, light speed limited latency, and power densities on the order of 1 mW/cm$^2$ for neurons with 700 connections operating at full speed at 2 K. The processing units achieve an energy efficiency of \\approx 20$ aJ per synapse event. By leveraging multilayer photonics with deposited waveguides and superconductors with feature sizes 100 nm, this approach could scale to systems with massive interconnectivity and complexity for advanced computing as well as explorations of information processing capacity in systems with an enormous number of information bearing microstates.", "author_names": [ "Jeffrey M Shainline", "Sonia M Buckley", "Richard P Mirin", "Sae Woo Nam" ], "corpus_id": 1518168, "doc_id": "1518168", "n_citations": 99, "n_key_citations": 1, "score": 1, "title": "Superconducting optoelectronic circuits for neuromorphic computing", "venue": "ArXiv", "year": 2016 }, { "abstract": "We have previously proposed a novel hardware platform (SOEN) for neuromorphic computing based on superconducting optoelectronics that presents many of the features necessary for information processing in the brain. Here we discuss the design and training of networks of neurons and synapses based on this technology. We present circuit models for the simplest neurons and synapses that we can use to build networks. We discuss the further abstracted integrate and fire model that we use for evolutionary optimization of small networks of these neurons. We show that we can use the TENNLab evolutionary optimization programming framework to design small networks for logic, control and classification tasks. We plan to use the results as feedback to inform our neuron design.", "author_names": [ "Sonia M Buckley", "Adam Nykoruk McCaughan", "Jeff Chiles", "Richard P Mirin", "Sae Woo Nam", "Jeffrey M Shainline", "Grant Bruer", "James S Plank", "Catherine D Schuman" ], "corpus_id": 53648717, "doc_id": "53648717", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Design of Superconducting Optoelectronic Networks for Neuromorphic Computing", "venue": "2018 IEEE International Conference on Rebooting Computing (ICRC)", "year": 2018 }, { "abstract": "We have previously proposed a novel hardware platform (SOEN) for neuromorphic computing based on superconducting optoelectronics that presents many of the features necessary for information processing in the brain. Here we discuss the design and training of networks of neurons and synapses based on this technology. We present circuit models for the simplest neurons and synapses that we can use to build networks. We discuss the further abstracted integrate and fire model that we use for evolutionary optimization of small networks of these neurons. We show that we can use the TENNLab evolutionary optimization programming framework to design small networks for logic, control and classification tasks. We plan to use the results as feedback to inform our neuron design.", "author_names": [ "Sonia M Buckley", "Adam Nykoruk McCaughan", "Jeff Chiles", "Richard P Mirin", "Sae Woo Nam", "Jeffrey M Shainline", "Grant Bruer", "James S Plank", "Catherine D Schuman" ], "corpus_id": 199019943, "doc_id": "199019943", "n_citations": 2, "n_key_citations": 1, "score": 0, "title": "Design of Superconducting Optoelectronic Networks for Neuromorphic Computing", "venue": "", "year": 2018 }, { "abstract": "We propose a hybrid semiconductor superconductor hardware platform for the implementation of neural networks and large scale neuromorphic computing. The platform combines semiconducting few photon light emitting diodes with superconducting nanowire single photon detectors to behave as spiking neurons.", "author_names": [ "Sonia M Buckley", "Adam Nykoruk McCaughan", "Jeff Chiles", "Richard P Mirin", "Sae Woo Nam", "Jeffrey M Shainline" ], "corpus_id": 32069588, "doc_id": "32069588", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Superconducting optoelectronic platform for neuromorphic computing", "venue": "2017 Conference on Lasers and Electro Optics (CLEO)", "year": 2017 }, { "abstract": "Abstract Optically stimulated synaptic devices are critical to the development of neuromorphic computing with broad bandwidth and efficient interconnect. Although a few interesting materials have been employed to fabricate optically stimulated synaptic devices, the use of silicon (Si) that is the material of choice for very large scale integration circuits in the conventional von Neumann computing has not been explored for optically stimulated synaptic devices. Here we take advantage of one of the most important nanostructures of Si Si nanocrystals (NCs) to make synaptic devices, which can be effectively stimulated by light in the unprecedented broad spectral region from the ultraviolet to near infrared, approaching the wavelength of 2 um. These optically stimulated Si NC based synaptic devices demonstrate a series of important synaptic functionalities, well mimicking biological synapses. The plasticity of Si NC based synaptic devices originates from the dynamic trapping and release of photogenerated carriers at defects such as dangling bonds at the NC surface. The current facile use of Si NCs in broadband optoelectronic synaptic devices with low energy consumption has important implication for the large scale deployment of Si in the emerging neuromorphic computing.", "author_names": [ "Hua Tan", "Zhenyi Ni", "Wenbing Peng", "Sichao Du", "Xiangkai Liu", "Shuangyi Zhao", "Wei Li", "Zhizhen Ye", "Mingsheng Xu", "Yang Xu", "Xiaodong Pi", "Deren Yang" ], "corpus_id": 139366398, "doc_id": "139366398", "n_citations": 68, "n_key_citations": 0, "score": 0, "title": "Broadband optoelectronic synaptic devices based on silicon nanocrystals for neuromorphic computing", "venue": "", "year": 2018 }, { "abstract": "Superconducting circuits based on quantum phase slip junctions (QPSJs) can conduct quantized charge pulses, which naturally resemble action potentials generated by biological neurons. A corresponding synaptic circuit, which works as a weighted connection between two neurons, can also be realized by circuits comprised of QPSJs and magnetic Josephson junctions (MJJs) as a means of charge modulation for quantized charge propagation. In this paper, we present basic neuromorphic computing circuitry components, such as neuron and synaptic circuits, based on superconducting QPSJs and MJJs. Using a SPICE model developed for QPSJs, neuron and synaptic circuits were simulated in WRSPICE to demonstrate possible operation. We provide estimates for QPSJ energy dissipation and operation speed based on calculations using simple models. Some of the challenges for implementation of this technology are also briefly discussed.", "author_names": [ "Ran Cheng", "Uday S Goteti", "Michael C Hamilton" ], "corpus_id": 56170414, "doc_id": "56170414", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Superconducting Neuromorphic Computing Using Quantum Phase Slip Junctions", "venue": "IEEE Transactions on Applied Superconductivity", "year": 2019 }, { "abstract": "Abstract We report an artificial optoelectronic synapse based on a copper phthalocyanine (CuPc) and para sexiphenyl (p 6P) heterojunction structure. This device features stable conductance states and their linear distribution in long term potentiation (LTP) characteristic curve formed by continuous input light pulses. These superior synaptic characteristics originate from the fact that the number of photo holes moving into the CuPc channel and photo electrons being trapped at the p 6P/dielectric interface is constant at every light pulse. A single layer neural network is theoretically formed with these optoelectronic synaptic devices and its feasibility is studied in terms of training/recognition tasks of the Modified National Institute of Standards and Technology digit image patterns. Owing to the excellent LTP characteristic and through the use of a unidirectional update method, its maximum recognition rate is as high as 78% despite the use of a single layer network. This study is expected to provide a foundation for future studies on optoelectronic synaptic devices toward the implementation of complex artificial neural networks.", "author_names": [ "Chuan Qian", "Seyong Oh", "Yongsuk Choi", "Jia Sun", "Han Huang", "Junliang Yang", "Yongli Gao", "Jin-Hong Park", "Jeong Ho Cho" ], "corpus_id": 202949753, "doc_id": "202949753", "n_citations": 29, "n_key_citations": 0, "score": 0, "title": "Solar stimulated optoelectronic synapse based on organic heterojunction with linearly potentiated synaptic weight for neuromorphic computing", "venue": "", "year": 2019 }, { "abstract": "Superconducting optoelectronic hardware has been proposed for large scale neural computing. In this work, we expand upon the circuit and network designs previously introduced. We investigate circuits using superconducting single photon detectors and Josephson junctions to perform signal reception, synaptic weighting, and integration. Designs are presented for synapses and neurons that perform integration of rate coded signals as well as detect coincidence events for temporal coding. A neuron with a single integration loop can receive input from thousands of synaptic connections, and many such loops can be employed for dendritic processing. We show that a synaptic weight can be modified via a superconducting flux storage loop inductively coupled to the current bias of the synapse. Synapses with hundreds of stable states are designed. Spike timing dependent plasticity can be implemented using two photons to strengthen and two photons to weaken the synaptic weight via Hebbian type learning rules. In addition to the synaptic receiver and plasticity circuits, we describe an amplifier chain that converts the current pulse generated when a neuron reaches threshold to a voltage pulse sufficient to produce light from a semiconductor diode. This light is the signal used to communicate between neurons in the network. We analyze the performance of the elements in the amplifier chain to calculate the energy consumption per photon created. The speed of the amplification sequence allows neuronal firing up to at least 20 MHz, independent of connectivity. We consider these neurons in network configurations to investigate near term technological potential and long term physical limitations. By modeling the physical size of superconducting optoelectronic neurons, we calculate the area of these networks. A system with 8100 neurons and 330 430 total synapses will fit on a 1 x 1 cm 2 die. Systems of millions of neurons with hundreds of millions of synapses will fit on a 300 mm wafer. For multiwafer assemblies, communication at light speed enables a neuronal pool the size of a large data center 10 5 m 2) comprised of trillions of neurons with coherent oscillations at 1 MHz.Superconducting optoelectronic hardware has been proposed for large scale neural computing. In this work, we expand upon the circuit and network designs previously introduced. We investigate circuits using superconducting single photon detectors and Josephson junctions to perform signal reception, synaptic weighting, and integration. Designs are presented for synapses and neurons that perform integration of rate coded signals as well as detect coincidence events for temporal coding. A neuron with a single integration loop can receive input from thousands of synaptic connections, and many such loops can be employed for dendritic processing. We show that a synaptic weight can be modified via a superconducting flux storage loop inductively coupled to the current bias of the synapse. Synapses with hundreds of stable states are designed. Spike timing dependent plasticity can be implemented using two photons to strengthen and two photons to weaken the synaptic weight via Hebbian type learning rules. In addition.", "author_names": [ "Jeffrey M Shainline", "Sonia M Buckley", "Adam Nykoruk McCaughan", "Jeff Chiles", "Amir Jafari Salim", "Manuel A Castellanos-Beltran", "Christine A Donnelly", "Michael L Schneider", "Richard P Mirin", "Sae Woo Nam" ], "corpus_id": 199669267, "doc_id": "199669267", "n_citations": 22, "n_key_citations": 3, "score": 0, "title": "Superconducting optoelectronic loop neurons", "venue": "Journal of Applied Physics", "year": 2019 }, { "abstract": "Advanced neuromorphic systems require massive interconnectivity, extreme energy efficiency, and complex signaling mechanisms. Here we propose an integrated optoelectronic platform utilizing superconducting electronics with photonic signaling to enable neuromorphic computing beyond the scale of the human brain.", "author_names": [ "Sonia M Buckley", "Jeff Chiles", "Adam Nykoruk McCaughan", "Richard P Mirin", "Sae Woo Nam", "Jeffrey M Shainline" ], "corpus_id": 38844222, "doc_id": "38844222", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Photonic interconnect with superconducting electronics for large scale neuromorphic computing (Invited paper)", "venue": "2017 IEEE Photonics Society Summer Topical Meeting Series (SUM)", "year": 2017 }, { "abstract": "As one of the most important members of the two dimensional chalcogenide family, molybdenum disulphide (MoS2) has played a fundamental role in the advancement of low dimensional electronic, optoelectronic and piezoelectric designs. Here, we demonstrate a new approach to solid state synaptic transistors using two dimensional MoS2 floating gate memories. By using an extended floating gate architecture which allows the device to be operated at near ideal subthreshold swing of 77 mV/decade over four decades of drain current, we have realised a charge tunneling based synaptic memory with performance comparable to the state of the art in neuromorphic designs. The device successfully demonstrates various features of a biological synapse, including pulsed potentiation and relaxation of channel conductance, as well as spike time dependent plasticity (STDP) Our device returns excellent energy efficiency figures and provides a robust platform based on ultrathin two dimensional nanosheets for future neuromorphic applications.", "author_names": [ "Tathagata Paul", "Tanweer Ahmed", "Krishna Kanhaiya Tiwari", "Chetan Singh Thakur", "Arindam Ghosh" ], "corpus_id": 102351171, "doc_id": "102351171", "n_citations": 28, "n_key_citations": 0, "score": 0, "title": "A high performance MoS2 synaptic device with floating gate engineering for Neuromorphic Computing", "venue": "2D Materials", "year": 2019 } ]

[ { "abstract": "To carry out theoretical analysis of the constant current source of the high stability semiconductor laser, and to perform in depth experiments and research on this basis. It used certain technical means, and the stability and safety of the laser's power supply were tested and studied based on theoretical analysis of the constant current source of the high stability conductor laser. According to the experimental results, it was proved that the development of high stability laser power supply was of great significance to the stability and safety of the laser power supply. In improving the stability and safety of semiconductor laser constant current sources, the application of high stability driving power that meets international standards has significantly improved the stability of output power and extended the use time. Therefore, it has certain value of application and promotion.", "author_names": [ "Libo Wu", "Qinxin Wang", "Shuqing Ma", "Zhen Yin", "Jianping Xu", "Liyan Zhao" ], "corpus_id": 199385146, "doc_id": "199385146", "n_citations": 1, "n_key_citations": 0, "score": 3, "title": "Theoretical Analysis and Experimental Research on Constant Current Source of High Stability Semiconductor Laser", "venue": "", "year": 2018 }, { "abstract": "In order to achieve the goal of constant output light power, the design of high accuracy digital control semiconductor laser constant current source is very important. Semiconductor laser is can be divided into load floating and load grounding two types based on the package. In this paper, a small power grounding type digital control semiconductor laser constant current source is realized by using ARM processor. By using this method, the semiconductor laser can be provided within the range of 0mA 500mA constant current. At same time, some functions such as slow start, temperature control, overcurrent protection are realized. In actual experiment test result show, the design method is stable, reliable and high accuracy.", "author_names": [ "Tonggang Zhao", "Chuanlong Huang" ], "corpus_id": 110948276, "doc_id": "110948276", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "The design and implementation of high accuracy digital control semiconductor laser constant current source", "venue": "Other Conferences", "year": 2013 }, { "abstract": "In order to satisfy high power and high stability requirements of the laser K98SA3F 30.00W R(operating current 12A,ripple coefficient requirement 0.05%,a constant current source circuit was designed.Its output current can realize high efficiency,high precision and high stability by the chip LTC1625,LT1620,MOSFET IRF7811,digital potentiometers AD5231 and a p type filter.The LTC1625 is a current mode synchronous step down switching regulator and the LT1620 is a current sense amplifier.The simulation results given by LTspiceIV show that,when working in constant current mode,the output current can be changed continuously from zero to 20A,the minimum variable stepping current value is 0.061A,the output current ripple coefficient of the circuit can be less than 0.001%.Results indicate the circuit can meet the application requirements of the semiconductor laser diode K98SA3F 30.00W R.", "author_names": [ "Kong Ling-hang" ], "corpus_id": 111792942, "doc_id": "111792942", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Design of constant current source for high power semiconductor laser diode", "venue": "", "year": 2012 }, { "abstract": "The pulse constant current source for the semiconductor laser is designed.The system adopts high power MOSFET and operational amplifier which has high common mode rejection ratio and low temperature drift as hard core.Moreover,the control technology of MCU and high precision D/A chip are combined to set the current and pulse length.In addition,the tunable voltage stabilizer using VICOR modules in series structure and several protecting circuits are also introduced,which is specified as wide tuning range of the voltage,high control precision,good stability,high adaptability to the high low temperature,and so on.", "author_names": [ "Ge Hong-wei" ], "corpus_id": 113893691, "doc_id": "113893691", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Research on High Pulse Constant Current Source for the Semiconductor Laser", "venue": "", "year": 2012 }, { "abstract": "A design of digital controlled constant current source for a high power semiconductor laser diode based on ADuC812 is described. The constant current source used a high power MOSFET as the current control device and a Hall current sensor as the feedback device of the sample current. The over current protection circuit and median filter arithmetic in software are designed to ensure stability and safety of laser diode operation. The practical application indicates that the constant current source is safe and reliable to the laser diode, with the linear control of the output current ranged from 0 to 50 Ampere and the 0.1 ampere precision.", "author_names": [ "Xianming Xiong", "Ying Huang", "Fangrong Hu" ], "corpus_id": 41136134, "doc_id": "41136134", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The design of constant current source of high power Semiconductor laser diode based on ADuC812", "venue": "2007 International Conference on Communications, Circuits and Systems", "year": 2007 }, { "abstract": "To meet the high power and high stability requirements of BWT 915 10W and 915 30W pumped semiconductor laser (with adjustable current from 0 to 12A, current ripple factor less than 2% a dual control and dual output circuit is designed to allow the power supply output current adjustable from 0 to 12A. It is called dual control because power can control manually by an external knob to achieve current continuously adjustable, and also through DSP28035 to achieve current digital regulation. Temperature detection with protection circuits is also designed, and so is highly reflective pulsed light detection with protection circuits. The output state of the DSP is controlled by signals from the control card. They communicate each other through A 25 pin parallel port. By designing schematics, producing PCB and repeated tests, it is indicated that this dual power supply is a small ripple, high stability and efficient, small volume and light weight switching power supply.", "author_names": [ "Xue Huiyun", "Che Yanbo", "Teng Wen", "Ma Yage", "Ge Leijiao" ], "corpus_id": 41778509, "doc_id": "41778509", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design of dual control and dual output constant current source for semi conductor laser diode", "venue": "2013 5th International Conference on Power Electronics Systems and Applications(PESA)", "year": 2013 }, { "abstract": "Design and realization methods of integrated operational amplifier feedback constant current power in semiconductor laser reliability evaluation system are introduced in this paper.This numerical control constant current source with the core of single chip microcomputer can provide exact control for the output current,the control could attain milliampere level.This constant current source uses a high power darlington transistor as the current control device,the value and the range of the output current that can be adjusted are very large.The constant current source has protective and slow start function,so it not only can provide power for semiconductor laser,but also can effectively protect the laser.", "author_names": [ "Ruan Ying" ], "corpus_id": 64373065, "doc_id": "64373065", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design of Constant Current Source in Semiconductor Laser Reliability Evaluation System", "venue": "", "year": 2005 }, { "abstract": "Abstract The semiconductor laser is the important part in the semiconductor laser frequency standard. The quality of light frequency standard depends on line width and stability of laser. Semiconductor laser is very sensitive to environmental changes, such as the temperature, humidity and so on. The driving voltage and circuit and the temperature compensation are significant to laser output stability. The paper put forward a novel method to drive the semiconductor laser based on constant voltage source. The experimental results show that the circuit is simple, reliable, and high precision. After improvement, the driving source of laser can promise parameters: constant current range is from 0 to 250 mA, and the drift of current is less than 10 6 and stability is 10 5 The drift of frequency of laser drive with the circuit is within 10 5 nm.", "author_names": [ "Zhifeng Zhang", "Yusheng Zhai", "S U Zhan", "Yuling Su", "Xinjie Wang", "Yin-Xiao Du" ], "corpus_id": 106511942, "doc_id": "106511942", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "A novel method to drive semiconductor laser for optical frequency standard based on constant voltage source", "venue": "", "year": 2015 }, { "abstract": "Small portable power semiconductor lasers( LD) have features of low voltage driving,safety incentives,high efficiency. It is widely used in terms of long distance communication,laser ranging,and holographic applications. LD stable optical power output and portability require high stability and small size of driving power,while requiring constant current output. Taking the synchronous buck( SR BUCK) topology with efficient controller as the constant current source core,the paper designed the high precision dual channel constant current source driving system with current adjustable. The constant current source used the current loop PI regulator negative feedback system,added voltage disturbance feed forward,compared the output current,adjusted and improved the accuracy of the system.Meanwhile,it completed the mathematical modeling and simulation systems,while testing and evaluating the system.The test results show that the constant current source has the characteristics of high overall efficiency,fast dynamic response time( 10ms),high output capacity( 300 watts) and stability( no overshoot),low ripple factor( 0. 075%,adjustment range( 0 12A),strong anti interference ability and so on.", "author_names": [ "Hu Xiao-qin" ], "corpus_id": 111858777, "doc_id": "111858777", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design of High precision Dual channel Constant Current Driving Source for Laser Diode", "venue": "", "year": 2015 }, { "abstract": "To some degree,the performance of semiconductor lasers is influenced by temperature,in order to improve the stability of their work,this paper designed a temperature control system semiconductor lasers.The system used 0.5 mA constant current source to supply power for Pt100 temperature sensor,four wire measurement method was used to obtain accurate temperature signal.TLC2652 chopper amplifier was applied to design preamplifier.And a differential amplifier circuit was used to subsequently compare and amplify signal.The semiconductor cooler(TEC) was applied to achieve constant temperature control of the system.After the experimental data analysis,we can see that the constant temperature system can effectively work,the maximum deviation of temperature control is 0.02 .By adjusting the corresponding parameters,the temperature thermostat of system can be free to set,so as to use it in different temperature control environments.", "author_names": [ "Ding Guo-chao" ], "corpus_id": 113378284, "doc_id": "113378284", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Research on high precision temperature measurement of constant temperature control system of semiconductor laser", "venue": "", "year": 2012 } ]

[ { "abstract": "Designers typically add design margins to semiconductor memories to compensate for aging. However, the aging impact increases with technology downscaling, leading to the need for higher margins. This results into a negative impact on area, yield, performance, and power consumption. As an alternative, mitigation schemes can be developed to reduce such impact. This paper proposes a mitigation scheme for the memory's sense amplifier (SA) the scheme is based on creating a skew in the relative strengths of the SA's cross coupled inverters during design. The skew is compensated by aging due to unbalanced workloads. As a result, the impact of aging on the SA is reduced. To validate the mitigation scheme, the degradation of the sense amplifier is analyzed for several workloads. The experimental results show that the proposed mitigation scheme reduces the degradation of the sense amplifier's critical figure of merit, the offset voltage, with up to 26%", "author_names": [ "Daniel Kraak", "Mottaqiallah Taouil", "Said Hamdioui", "Pieter Weckx", "Stefan Cosemans", "Francky Catthoor" ], "corpus_id": 219857622, "doc_id": "219857622", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Mitigation of Sense Amplifier Degradation Using Skewed Design", "venue": "2020 Design, Automation Test in Europe Conference Exhibition (DATE)", "year": 2020 }, { "abstract": "To compensate for time zero (due to process variation) and time dependent (due to e.g. Bias Temperature Instability (BTI) variability, designers usually add design margins. Due to technology scaling, these variabilities become worse, leading to the need for bigger design margins. Typically, only worst case scenarios are considered, which will not present the actual workload of the targeted application. Alternatively, mitigation schemes can be used to counteract the variability. This paper presents a run time design for reliability scheme for memory Sense Amplifiers (SAs) SAs are an integral part of any memory system and are very critical for high performance. The proposed scheme mitigates the impact of time dependent variability due to aging by using an on line control circuit to create a balanced workload. The simulation results show that the proposed scheme can reduce the most critical figures of merit, namely the offset voltage shift and the sensing delay of the SA with up to ~40% and ~10% respectively, depending on the stress conditions (temperature, voltage, workload)", "author_names": [ "Daniel Kraak", "Innocent Okwudili Agbo", "Mottaqiallah Taouil", "Said Hamdioui", "Pieter Weckx", "Stefan Cosemans", "Francky Catthoor", "Wim Dehaene" ], "corpus_id": 37393756, "doc_id": "37393756", "n_citations": 14, "n_key_citations": 2, "score": 0, "title": "Mitigation of sense amplifier degradation using input switching", "venue": "Design, Automation Test in Europe Conference Exhibition (DATE) 2017", "year": 2017 }, { "abstract": "Designers typically add design margins to compensate for time zero variability (due to process variation) and time dependent (due to, e.g. bias temperature instability) variability. These variabilities become worse with scaling, which leads to larger design margin requirements. As an alternative, mitigation schemes can be applied to counteract the variability. This paper investigates the impact of aging on the offset voltage of the memory's sense amplifier (SA) For the analysis, the degradation of the SAs in the L1 data and instruction caches of an ARM processor is quantified while using realistic workloads extracted from the SPEC CPU2006 Benchmark suite. Furthermore, the effect of our mitigation scheme, i.e. an online control circuit that balances the SA workload, is analyzed. The simulation results show that the mitigation scheme reduces the offset voltage degradation due to aging with up to 40% for the benchmarks, depending on the stress conditions (temperature, voltage, and workload)", "author_names": [ "Daniel Kraak", "Mottaqiallah Taouil", "Innocent Okwudili Agbo", "Said Hamdioui", "Pieter Weckx", "Stefan Cosemans", "Francky Catthoor" ], "corpus_id": 4915830, "doc_id": "4915830", "n_citations": 13, "n_key_citations": 4, "score": 0, "title": "Impact and Mitigation of Sense Amplifier Aging Degradation Using Realistic Workloads", "venue": "IEEE Transactions on Very Large Scale Integration (VLSI) Systems", "year": 2017 }, { "abstract": "1T1R spin transfer torque (STT) MRAM is a promising candidate for next generation high density embedded non volatile memory [1 2] However, 1T1R STT MRAM suffers from limited sensing margin and high write power. As shown in Fig. 30.2.1(a) sense amplifier design is challenging due to the small difference (only 2x) between the high resistance state (RAP) and the low resistance state (RP) as well as RAP degradation with increasing temperature. Moreover, RP and RAP resistance distributions shift with process variation, requiring a read reference (Vref) that tracks process. To improve the sensing margin, several offset cancellation methods have been reported to reduce sense amplifier mismatch [3] However, these methods use multiple capacitors and hence incur significant area overheads. To address this issue, we propose an offset cancelled sense amplifier that uses only a single capacitor to significantly improve the sensing margin by more than 60% A second design challenge for STT MRAM stems from the high current needed to flip a cell during a write operation. For non volatile memory applications with a 10 year retention time requirement, the write current can be as high as several hundred mA. However, as shown in Fig. 30.2.1(b) the required write time varies with the state change required (0 1 or 1 0) process variation, and temperature. As a result, a fixed write time that ensures successful write for all conditions wastes a significant energy for typical or average conditions. We propose an in situ write self termination method to reduce write energy in most scenarios. The sense amplifier is reconfigured to continuously monitor the write operation and automatically shuts off the write drivers when the state transition is detected, without an area or timing penalty. In addition, dual dummy columns are added in each array to provide read Vref tracking of row wise PVT variation. A 1Mb STT MRAM was fabricated in 28nm technology, and achieves a 2.8ns read access time at 25degC and 3.6ns at 120degC, respectively. With in situ self write termination the write power is reduced by 47% with a 20ns write access time at 25degC and by 60% at 120degC.", "author_names": [ "Qing Dong", "Zhehong Wang", "Jongyup Lim", "Yiqun Zhang", "Yi-Chun Shih", "Y D Chih", "Tsung-Yung Jonathan Chang", "David Blaauw", "Dennis Sylvester" ], "corpus_id": 3856510, "doc_id": "3856510", "n_citations": 48, "n_key_citations": 10, "score": 0, "title": "A 1Mb 28nm STT MRAM with 2.8ns read access time at 1.2V VDD using single cap offset cancelled sense amplifier and in situ self write termination", "venue": "2018 IEEE International Solid State Circuits Conference (ISSCC)", "year": 2018 }, { "abstract": "This paper investigates the reliability tolerant design for ultra thin body (UTB) GeOI 6T SRAM cell and sense amplifiers. For UTB GeOI 6T SRAM cells, using high threshold voltage design significantly mitigates the read and hold static noise margin degradations due to NBTI and PBTI. Due to worse PBTI degradations, as stress (aging) time increases, GeOI current and voltage latch sense amplifiers show larger degradation in word line to sense amplifier enable (SAE) delay <inline formula> <tex math notation=\"LaTeX\"\\text{T}_{\\mathrm{ WS} /tex math>/inline formula> and sense amplifier sensing delay <inline formula> <tex math notation=\"LaTeX\"\\text{T}_{\\mathrm{ SA} /tex math>/inline formula> compared with the SOI counterparts. Using WL to SAE self timed sensing scheme mitigates the BTI induced delay degradation. A new reliability tolerant sense amplifier with speed up design is proposed for the first time to improve the PBTI dominated sensing delay for UTB GeOI sense amplifier.", "author_names": [ "Vita Pi-Ho Hu" ], "corpus_id": 13209460, "doc_id": "13209460", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Reliability Tolerant Design for Ultra Thin Body GeOI 6T SRAM Cell and Sense Amplifier", "venue": "IEEE Journal of the Electron Devices Society", "year": 2017 }, { "abstract": "Today to compete the race of improvements and advancements of technological mysteries are lasting upon innovative ideas and noble thoughts. The consequences of using normal Master Slave Flip flops in ultra high speed circuits are increase in cycle time, blurredness in clock edge skew, higher crosstalk substrate coupling/power consumption/ expensive packaging including cooling systems and limiting performance. An innovative idea of Sense amplifier based Flip flops (SAFF) has been implemented which can be speedup the processes up to optimum rate (i.e. Shannon Rate) with compensated SNR. To save the Time Element, designed prototype model to be operated, with ultra high speed for error detection and performance evaluation. Referred to authors previous paper, Modeling and design optimization of Latch Circuits using Parametric Timing Analysis, the latch circuits were thoroughly analyzed w.r.t. their operating speed and its effect over various parameters was discussed, in tighter timing constraints needs to concentrate on power dissipation and durability of device. Overlooking of setup and hold times spans, pays a heavy cost of compromise in the circuits with various latch ups inducted during design, testing and quality check phase. In sense amplifierflip flop (SAFF) based structures, delay can be fairly minimized between the latest point of data arrival and output transition using hybrid latch flip flop (HLFF) and semidynamic flip flop (SDFF) SAFF based latch models, consists of the sense amplifier in the first stage and the RS latch in the second stage which are being implemented and simulated by using the Cadence Spectre design tool using 45nm technology. It senses the true and complementary differential inputs and produces monotonous transitions from high to low logic or vice versa outputs for S R Latch following the leading clock edge. The S R latch captures each transition and holds the state until the next leading clock edge arrives, due to this feature; the whole structure becomes a self sustaining flip flop device.", "author_names": [ "Akhilesh Tiwari", "Shyam Akashe" ], "corpus_id": 21086514, "doc_id": "21086514", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Modeling and designing of Sense Amplifier based Flip Flop using Cadence tool at 45 nm", "venue": "", "year": 2017 }, { "abstract": "This paper describes the design and implementation of an embedded ROM memory along with its sense amplifier. Several applications in machine learning have fixed data to be stored in a memory, which needs to be read out multiple times. Hence a fast, on chip solution is proposed in this technical paper wherein logic transistors are used to design a read only memory with completely zero added process complexity. Several design constraints of sensing the ROM cell have been elaborated to a great extent. Also, a key advantage in the sense amplifier used is the ability to use all transistors from the same process technology. Further, by always fixing a MOS device in saturation and the other MOS device in cut off region, fast sensing is achieved at the sense amplifier output. The layout designed for the sense amplifier is verified to produce a very minimal deviation from the actual schematic simulations, hence suggesting a considerably well designed layout. The operating frequency of the sense amplifier is determined as 12.5 GHz with full swing resolution.", "author_names": [ "V Balaji", "Ch K S D Ranga", "N Shylashree", "Nuthakki Praveena" ], "corpus_id": 212637272, "doc_id": "212637272", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design of a Delta Threshold Voltage Difference based fully Embedded Read Only Memory along with a Skew Sense Amplifier", "venue": "2019 4th International Conference on Recent Trends on Electronics, Information, Communication Technology (RTEICT)", "year": 2019 }, { "abstract": "Nowadays, typical (memory) designers add design margins to compensate for uncertainties, however, this may be overestimated leading to yield loss, or underestimated leading to reduced reliability designs. Accurate quantification of all uncertainties is therefore critical to provide high quality and optimal designs. These uncertainties are caused by zero time variability (due to process variability) and by run time variability(due to environmental variabilities such as voltage and temperature, or due to temporal variability such as aging) This paper uses an accurate methodology to predict the impact of both zero and run time variability on the offset voltage of sense amplifiers while considering different workloads and PVT variations for a pre defined failure rate. The results show a marginal impact of environmental run time variability on the offset specification when considering zero time variability only, while this becomes significant (up to 2X) when incorporating aging run time variability. The results can be used to quantify whether the required offset voltage is met or not for the targeted lifetime, hence, enable the designer to take appropriate measures for an efficient and optimized design, depending on the targeted application lifetime.", "author_names": [ "Innocent Okwudili Agbo", "Mottaqiallah Taouil", "Said Hamdioui", "Pieter Weckx", "Stefan Cosemans", "Praveen Raghavan", "Francky Catthoor", "Wim Dehaene" ], "corpus_id": 14126432, "doc_id": "14126432", "n_citations": 21, "n_key_citations": 6, "score": 0, "title": "Quantification of Sense Amplifier Offset Voltage Degradation due to Zero and Run Time Variability", "venue": "2016 IEEE Computer Society Annual Symposium on VLSI (ISVLSI)", "year": 2016 }, { "abstract": "The continuous downscaling of CMOS technology causes increased impact of time zero (due to process variation) and time dependent variability (due to e.g. Bias Temperature Instability) This causes major challenges w.r.t. the device reliability, which is critical for industries, such as the automotive one. This paper uses an accurate method to quantify the impact of time zero and time dependent variability on the offset voltage specification of memory Sense Amplifiers. Furthermore, it presents a run time design for reliability scheme to mitigate the impact of time dependent variability on the offset voltage specification. The simulation results show that the mitigation scheme improves the offset voltage specification up to ~40% compared to the standard design after 10 years of aging.", "author_names": [ "Innocent Okwudili Agbo", "Mottaqiallah Taouil", "Said Hamdioui", "Pieter Weckx", "Stefan Cosemans", "Francky Catthoor", "Wim Dehaene" ], "corpus_id": 8769155, "doc_id": "8769155", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "On Mitigating Sense Amplifier Offset Voltage Degradation", "venue": "", "year": 2016 }, { "abstract": "This paper presents a high speed and low energy match line (ML) sensing scheme for ternary content addressable memory (TCAM) The proposed sensing scheme employs selective precharge which performs partial comparison on the TCAM words to eliminate most of the mismatched words from further comparison. Use of positive feedback in the sense amplifiers engaged in this phase speeds up search operation and reduces energy consumption. In the next phase, remaining portions of those words which were matched in the first phase are scanned to find the fully matched words. Lower resistance in the charging path of the sense amplifier in the second phase causes fast match detection. The proposed technique is simulated using 130nm 1.2V CMOS logic. Compared to conventional current race (CR) sensing scheme the proposed scheme shows 26.5% speed enhancement and at least 31% energy reduction at the cost of insignificant area overhead and small voltage margin degradation. Unlike many CR type schemes, no analog control voltage has been used in the proposed scheme.", "author_names": [ "Syed Iftekhar Ali", "M S Islam" ], "corpus_id": 5386015, "doc_id": "5386015", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "An Energy Efficient Design of High Speed Ternary CAM Using Match Line Segmentation and Resistive Feedback in Sense Amplifier", "venue": "J. Comput.", "year": 2012 } ]

[ { "abstract": "We present ab initio quantum mechanical molecular dynamics simulations of the liquid metal amorphous semiconductor transition in Ge. Our simulations are based on (a) finite temperature density functional theory of the one electron states, (b) exact energy minimization and hence calculation of the exact Hellmann Feynman forces after each molecular dynamics step using preconditioned conjugate gradient techniques, (c) accurate nonlocal pseudopotentials, and (d) Nos\\'e dynamics for generating a canonical ensemble. This method gives perfect control of the adiabaticity of the electron ion ensemble and allows us to perform simulations over more than 30 ps. The computer generated ensemble describes the structural, dynamic, and electronic properties of liquid and amorphous Ge in very good agreement with experiment. The simulation allows us to study in detail the changes in the structure property relationship through the metal semiconductor transition. We report a detailed analysis of the local structural properties and their changes induced by an annealing process. The geometrical, bonding, and spectral properties of defects in the disordered tetrahedral network are investigated and compared with experiment.", "author_names": [ "" ], "corpus_id": 37717671, "doc_id": "37717671", "n_citations": 12006, "n_key_citations": 83, "score": 0, "title": "Ab initio molecular dynamics simulation of the liquid metal amorphous semiconductor transition in germanium.", "venue": "Physical review. B, Condensed matter", "year": 1994 }, { "abstract": "From the Publisher: This book describes the extremely powerful technique of molecular dynamics simulation, which involves solving the classical many body problem in contexts relevant to the study of matter at the atomic level. The method allows the prediction of the static and dynamic properties of substances directly from the underlying interactions between the molecules. Because there is no alternative approach capable of handling such a broad range of problems at the required level of detail, molecular dynamics methods have proved themselves indispensable in both pure and applied research.", "author_names": [ "D C Rapaport" ], "corpus_id": 123084540, "doc_id": "123084540", "n_citations": 2812, "n_key_citations": 152, "score": 0, "title": "The Art of Molecular Dynamics Simulation", "venue": "", "year": 1997 }, { "abstract": "A new method for performing molecular dynamics simulations under constant pressure is presented. In the method, which is based on the extended system formalism introduced by Andersen, the deterministic equations of motion for the piston degree of freedom are replaced by a Langevin equation; a suitable choice of collision frequency then eliminates the unphysical 'ringing' of the volume associated with the piston mass. In this way it is similar to the 'weak coupling algorithm' developed by Berendsen and co workers to perform molecular dynamics simulation without piston mass effects. It is shown, however, that the weak coupling algorithm induces artifacts into the simulation which can be quite severe for inhomogeneous systems such as aqueous biopolymers or liquid/liquid interfaces.", "author_names": [ "Scott Feller", "Yuhong Zhang", "Richard W Pastor", "Bernard R Brooks" ], "corpus_id": 120867953, "doc_id": "120867953", "n_citations": 3036, "n_key_citations": 39, "score": 0, "title": "Constant pressure molecular dynamics simulation: The Langevin piston method", "venue": "", "year": 1995 }, { "abstract": "The impact of molecular dynamics (MD) simulations in molecular biology and drug discovery has expanded dramatically in recent years. These simulations capture the behavior of proteins and other biomolecules in full atomic detail and at very fine temporal resolution. Major improvements in simulation speed, accuracy, and accessibility, together with the proliferation of experimental structural data, have increased the appeal of biomolecular simulation to experimentalists a trend particularly noticeable in, although certainly not limited to, neuroscience. Simulations have proven valuable in deciphering functional mechanisms of proteins and other biomolecules, in uncovering the structural basis for disease, and in the design and optimization of small molecules, peptides, and proteins. Here we describe, in practical terms, the types of information MD simulations can provide and the ways in which they typically motivate further experimental work.", "author_names": [ "Scott A Hollingsworth", "Ron O Dror" ], "corpus_id": 52311344, "doc_id": "52311344", "n_citations": 320, "n_key_citations": 3, "score": 1, "title": "Molecular Dynamics Simulation for All", "venue": "Neuron", "year": 2018 }, { "abstract": "Can completely homogeneous nucleation occur? Large scale molecular dynamics simulations performed on a graphics processing unit rich supercomputer can shed light on this long standing issue. Here, a billion atom molecular dynamics simulation of homogeneous nucleation from an undercooled iron melt reveals that some satellite like small grains surrounding previously formed large grains exist in the middle of the nucleation process, which are not distributed uniformly. At the same time, grains with a twin boundary are formed by heterogeneous nucleation from the surface of the previously formed grains. The local heterogeneity in the distribution of grains is caused by the local accumulation of the icosahedral structure in the undercooled melt near the previously formed grains. This insight is mainly attributable to the multi graphics processing unit parallel computation combined with the rapid progress in high performance computational environments.Nucleation is a fundamental physical process, however it is a long standing issue whether completely homogeneous nucleation can occur. Here the authors reveal, via a billion atom molecular dynamics simulation, that local heterogeneity exists during homogeneous nucleation in an undercooled iron melt.", "author_names": [ "Yasushi Shibuta", "Shinji Sakane", "Eisuke Miyoshi", "Shinpei Okita", "Tomohiro Takaki", "Munekazu Ohno" ], "corpus_id": 4619241, "doc_id": "4619241", "n_citations": 135, "n_key_citations": 0, "score": 0, "title": "Heterogeneity in homogeneous nucleation from billion atom molecular dynamics simulation of solidification of pure metal", "venue": "Nature Communications", "year": 2017 }, { "abstract": "We present an extensive molecular dynamics simulation for a bead spring model of a melt of linear polymers. The number of monomers N covers the range from N=5 to N=400. Since the entanglement length Ne is found to be approximately 35, our chains cover the crossover from the nonentangled to the entangled regime. The Rouse model provides an excellent description for short chains N<Ne, while the dynamics of the long chains can be described by the reptation model. By mapping the model chains onto chemical species we give estimates of the times and distances of onset of the slowing down in motion due to reptation. Comparison to neutron spin echo data confirm our mapping procedure, resolving a discrepancy between various experiments. By considering the primitive chain we are able to directly visualize the confinement to a tube. Analyzing the Rouse mode relaxation allows us to exclude the generalized Rouse models, while the original reptation prediction gives a good description of the data.", "author_names": [ "Kurt Kremer", "Gary S Grest" ], "corpus_id": 95585319, "doc_id": "95585319", "n_citations": 2426, "n_key_citations": 61, "score": 0, "title": "Dynamics of entangled linear polymer melts: A molecular dynamics simulation", "venue": "", "year": 1990 }, { "abstract": "molecular dynamics simulation elementary methods is available in our book collection an online access to it is set as public so you can get it instantly. Our digital library spans in multiple locations, allowing you to get the most less latency time to download any of our books like this one. Merely said, the molecular dynamics simulation elementary methods is universally compatible with any devices to read.", "author_names": [ "Matthias Durr" ], "corpus_id": 64289230, "doc_id": "64289230", "n_citations": 107, "n_key_citations": 11, "score": 0, "title": "Molecular Dynamics Simulation Elementary Methods", "venue": "", "year": 2016 }, { "abstract": "Abstract Corrosion inhibition mechanism of two mercapto quinoline Schiff bases, eg. 3 (phenylimino)methyl)quinoline 2 thiol (PMQ) and 3 (5 methylthiazol 2 ylimino)methyl) quinoline 2 thiol (MMQT) on mild steel surface is investigated by quantum chemical calculation and molecular dynamics simulation. Quantum chemical parameters such as EHOMO, ELUMO, energy gap (DE) dipolemoment (u) electronegativity (kh) global hardness (e) and fraction of electron transfers from the inhibitor molecule to the metallic atom surface (DN) have been studied to investigate their relative corrosion inhibition performance. Parameters like local reactive sites of the present molecule have been analyzed through Fukui indices. Moreover, adsorption behavior of the inhibitor molecules on Fe (1 1 0) surface have been analyzed using molecular dynamics simulation. The binding strength of the concerned inhibitor molecules on mild steel surface follows the order MMQT>PMQ, which is in good agreement with the experimentally determined inhibition efficiencies. In view of the above, our approach will be helpful for quick prediction of a potential inhibitor from a lot of similar inhibitors and subsequently in their rational designed synthesis for corrosion inhibition application following a wet chemical synthetic route.", "author_names": [ "Sourav Saha", "Pritam Ghosh", "Abhiram Hens", "Naresh Chandra Murmu", "Priyabrata Banerjee" ], "corpus_id": 98293608, "doc_id": "98293608", "n_citations": 247, "n_key_citations": 0, "score": 0, "title": "Density functional theory and molecular dynamics simulation study on corrosion inhibition performance of mild steel by mercapto quinoline Schiff base corrosion inhibitor", "venue": "", "year": 2015 }, { "abstract": "Molecular dynamics (MD) simulation has enhanced our understanding about ductile regime machining of brittle materials such as silicon and germanium. In particular, MD simulation has helped understand the occurrence of brittle ductile transition due to the high pressure phase transformation (HPPT) which induces Herzfeld Mott transition. In this paper, relevant MD simulation studies in conjunction with experimental studies are reviewed with a focus on (i) the importance of machining variables: undeformed chip thickness, feed rate, depth of cut, geometry of the cutting tool in influencing the state of the deviatoric stresses to cause HPPT in silicon, (ii) the influence of material properties: role of fracture toughness and hardness, crystal structure and anisotropy of the material, and (iii) phenomenological understanding of the wear of diamond cutting tools, which are all non trivial for cost effective manufacturing of silicon. The ongoing developmental work on potential energy functions is reviewed to identify opportunities for overcoming the current limitations of MD simulations. Potential research areas relating to how MD simulation might help improve existing manufacturing technologies are identified which may be of particular interest to early stage researchers.", "author_names": [ "Saurav Goel", "Xichun Luo", "Anupam Agrawal", "Robert L Reuben" ], "corpus_id": 53977354, "doc_id": "53977354", "n_citations": 220, "n_key_citations": 1, "score": 0, "title": "Diamond machining of silicon: A review of advances in molecular dynamics simulation", "venue": "", "year": 2015 }, { "abstract": "", "author_names": [ "Zhigang Li" ], "corpus_id": 127533681, "doc_id": "127533681", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Molecular dynamics simulation", "venue": "", "year": 2018 } ]

[ { "abstract": "This paper studies the defect data analysis method for semiconductor yield enhancement. Given the defect locations on a wafer, the local defects generated from the assignable causes are classified from the global defects generated from the random causes by model based clustering, and the clustering methods can identify the characteristics of local defect clusters. The information obtained from this method can facilitate process control, particularly, root cause analysis. The global defects are modeled by the spatial non homogeneous Poisson process, and the local defects are modeled by the bivariate normal distribution or by the principal curve.", "author_names": [ "Jung Yoon Hwang", "Way Kuo" ], "corpus_id": 45569681, "doc_id": "45569681", "n_citations": 56, "n_key_citations": 4, "score": 1, "title": "Model based clustering for integrated circuit yield enhancement", "venue": "Eur. J. Oper. Res.", "year": 2007 }, { "abstract": "The manufacturing yield challenge of 3 D integrated circuit is one of the key obstacles in the industry adoption of 3 D integration based on through silicon vias (TSVs) The addition of spare TSVs to repair faulty functional TSVs (f TSVs) is an effective method for yield and reliability enhancement, but this approach results in significant hardware cost and delay overhead. Most existing solutions are only suitable for a \"dual uniform\" scenario in which both the placement and the defect probabilities of f TSVs are assumed to be uniform. In this paper, we propose a design technique that is compatible with nonuniform TSV placement and it can repair faulty TSVs based on a realistic clustered defect distribution model. The proposed solution is based on two consecutive stages, which utilize a greedy algorithm and an integer linear programming formulation, respectively. By considering the tradeoff between chip yield, hardware cost, and delay overhead, the proposed technique provides higher yield and reliability under a clustered defect distribution, and with minimum hardware cost and delay overhead, compared to the previous work.", "author_names": [ "Shengcheng Wang", "Krishnendu Chakrabarty", "Mehdi Baradaran Tahoori" ], "corpus_id": 69841948, "doc_id": "69841948", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Defect Clustering Aware Spare TSV Allocation in 3 D ICs for Yield Enhancement", "venue": "IEEE Transactions on Computer Aided Design of Integrated Circuits and Systems", "year": 2019 }, { "abstract": "The manufacturing yield challenge of three dimensional integrated circuit (3D ICs) is one of the key obstacles in the industry adoption of 3D integration based on through silicon vias (TSVs) The addition of spare TSVs to repair faulty functional TSVs is an effective method for yield and reliability enhancement, but this approach results in significant hardware cost and delay overhead. Most existing solutions are only suitable for a \"dual uniform\" scenario in which both the placement and the defect probabilities of functional TSVs are assumed to be uniform. In this paper, we propose a design technique that is compatible with non uniform TSV placement and it can repair faulty TSVs based on a realistic clustered defect distribution model. The proposed solution is based on two consecutive stages, which utilize a greedy algorithm and an integer linear programming formulation, respectively. By considering the trade off between chip yield, hardware cost, and delay overhead, the proposed technique provides higher yield and reliability under a clustered defect distribution, and with minimum hardware cost and delay overhead, compared to the previous work.", "author_names": [ "Shengcheng Wang", "Mehdi Baradaran Tahoori", "Krishnendu Chakrabarty" ], "corpus_id": 244035, "doc_id": "244035", "n_citations": 6, "n_key_citations": 2, "score": 0, "title": "Defect clustering aware spare TSV allocation for 3D ICs", "venue": "2015 IEEE/ACM International Conference on Computer Aided Design (ICCAD)", "year": 2015 }, { "abstract": "Clustered faults that affect the manufacture of integrated circuits are modeled by a simulation approach in which the fault formation is a function of time. In one such approach, the probability of generating a fault in a given subarea of an integrated circuit at any given time is assumed to depend on the number of faults already in that area and on the number of faults in the nearest neighbor adjacent subareas. Although such procedures had been used heuristically, technical considerations show that this stochastic approach actually is analytically justifiable. It is found that the resulting distribution functions, the joint probability distribution function, the distribution function of the sum of dependent random variables, and the correlation between these variables are identical to results obtained with a large area cluster model using compound Poisson statistics. This offers a unique insight into a statistical isomorphism that has been a puzzling issue.", "author_names": [ "Charles H Stapper" ], "corpus_id": 9704836, "doc_id": "9704836", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Statistics associated with spatial fault simulation used for evaluating integrated circuit yield enhancement", "venue": "IEEE Trans. Comput. Aided Des. Integr. Circuits Syst.", "year": 1991 }, { "abstract": "The manufacturing of integrated circuits is not a perfect fault free process. The constant downscaling of integrated circuits requiring higher accuracy each generation also allows the designer to fit more transistors in the same area. From a manufacturing point of view, this downscaling introduces additional possible sources of error, which forces a constant struggle to keep the yield or ratio of successfully manufactured chips high enough to be profitable. The manufacturing success ratio, or yield, is a major component of what determines the time and material cost it takes to manufacture an integrated circuit. To increase yield a common approach is to add redundant or spare parts to the system requiring only enough of them to work. Redundancy has long been a common concept in memories. For random logic blocks, the overhead cost has been too large to be reasonable. But for multi core systems, with several instances of the same logic block, the situation is starting to resemble the case of a memory. The manufacturing yield can be predicted by statistical models. Such models may consist of analytical expressions based on very low level information such as the exact layout features of every transistor and wire of the entire chip. However the addition of a spare core for a multi core cluster is an architectural decision that has to be made in the early stages of the design where low level details are not readily available. The modeling approach taken in this project uses a collection of simplified models previously used for yield calculations for memories. The model results in estimates of the yield before and after the addition of redundant cores. The input parameters to the model are based on gate counts and global routing estimates of an early floor plan together with information about the manufacturing process in the form a fault density. When sources of defects are found and suppressed, the yield ramps up. The yield model presented here also shows the effect the redundancy has on the yield ramp, pushing it towards an earlier volume production date, potentially decreasing the product time to market.", "author_names": [ "Mikael Andersson" ], "corpus_id": 108234988, "doc_id": "108234988", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Integrated Circuit Yield Enhancement Redundant Multi Core DSP Cluster", "venue": "", "year": 2010 }, { "abstract": "This paper proposes a new yield model for integrated circuits using a spatial point process. The defect density variation by location on a wafer is modeled by a spatial nonhomogeneous Poisson process. The intensity function of the yield model describes the defect pattern on wafers. As a result, the model differs from the existing compound Poisson yield models in its capability to describe the spatial defect distribution. Using model based clustering, the defect clusters from assignable causes, which contain the information about the variations of manufacturing processes, can be classified from others. The proposed model considers the defect density variation among wafers and the impact of defect size on the probability of a defect causing the circuit failure. The performance of the new yield model is verified using simulated data and real data. Simulation results show that the new yield model performs better than a compound Poisson yield model.", "author_names": [ "Jung Yoon Hwang", "Way Kuo", "Chunghun Ha" ], "corpus_id": 648217, "doc_id": "648217", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Modeling of Integrated Circuit Yield Using a Spatial Nonhomogeneous Poisson Process", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2011 }, { "abstract": "The integrated yield reliability model for integrated circuits allows one to estimate the yield, following both wafer probe and burn in testing. The model is based on the long observed clustering of defects and the experimentally verified relation between defects causing wafer probe failures, and defects causing infant mortality failures. The 2 parameter negative binomial distribution is used to describe the distribution of defects over a semiconductor wafer. The clustering parameter /spl alpha/ while known to play a key role in accurately determining wafer probe yields, is shown, for the first time, to play a similar role in determining burn in fall out. Numerical results indicate that the number of infant mortality failures predicted by the clustering model can differ appreciably from calculations that ignore clustering. This is particularly apparent when wafer probe yields are low, and clustering is high.", "author_names": [ "Thomas S Barnett", "Adit D Singh", "Victor P Nelson" ], "corpus_id": 8667478, "doc_id": "8667478", "n_citations": 31, "n_key_citations": 4, "score": 0, "title": "Extending integrated circuit yield models to estimate early life reliability", "venue": "IEEE Trans. Reliab.", "year": 2003 }, { "abstract": "This dissertation is focussed on developing new approaches for defect and yield modeling and yield enhancement. The research is inspired by the continuing trend of feature size reduction and chip area increments in integrated circuit (IC) manufacturing. A hierarchical taxonomic system for process defects is constructed. The taxonomic system possesses both predictive and explanatory powers, and is therefore a versatile tool in defect and yield modeling and yield enhancement. In defect modeling, a framework for modeling inter layer and intra layer short circuits and intra layer open circuits due to three dimensional spot defects is proposed. The main feature of this framework is parametrization of open circuits from the viewpoint of conductor's resistance, thereby allowing accurate estimations of defect sensitive regions in ICs. A yield model based on generalized Poisson statistics is developed to offer a natural explanation for the presence of defect clusters on integrated circuit chips and wafers. Also, several measures for empirical evaluation of spatial properties of defect patterns on wafers are proposed. Finally, a Design for Yield methodology at the layout synthesis level in IC design is proposed. The focus is on improving routing solutions in terms of layout critical area reduction against short circuits due to spot defects.", "author_names": [ "Aakash Tyagi" ], "corpus_id": 113516846, "doc_id": "113516846", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A framework for yield modeling and yield enhancement in integrated circuit design and fabrication", "venue": "", "year": 1993 }, { "abstract": "Two models for the effect of area scaling on reliability are derived from two distinct yield models with different assumptions on defect distributions. One is derived from the Poisson yield model assuming a uniform random distribution of defects as in an early model. The other is based on the negative binomial yield model to account for deviation from a uniform random distribution of defects caused by clustering. Experimental data from backend test structures show that the model based on defect clustering explains observed data well while the model assuming a uniform random distribution shows a significant departure from it.", "author_names": [ "Changsoo Hong", "Linda S Milor", "Munkang Choi", "To Ki Lin" ], "corpus_id": 46070758, "doc_id": "46070758", "n_citations": 10, "n_key_citations": 1, "score": 0, "title": "Study of Area Scaling Effect on Integrated Circuit Reliability Based on Yield Models", "venue": "Microelectron. Reliab.", "year": 2005 }, { "abstract": "Accurate yield prediction to evaluate productivity, and to estimate production costs, is a critical issue in the highly competitive semiconductor industry. We propose yield models based on hierarchical Bayesian modeling of clustered spatial defects produced in integrated circuits (IC) manufacturing. We use spatial locations of the IC chips on the wafers as covariates, and develop four models based on Poisson regression, negative binomial (NB) regression, zero inflated Poisson (ZIP) regression, and zero inflated negative binomial (ZINB) regression. Along with the hierarchical Bayesian approaches, spatial variations of defects within one wafer as well as among different wafers are effectively incorporated in the yield models. Wafermap data obtained from an industrial collaborator are used to illustrate the proposed models. The results indicate that the Poisson regression model consistently underestimates the true yield because of extraneous Poisson variation caused by defect clustering. On the contrary, NB regression, ZIP regression, and ZINB regression models provide more reliable yield estimation and prediction in real applications.", "author_names": [ "Tao Yuan", "Saleem Z Ramadan", "Suk Joo Bae" ], "corpus_id": 15580078, "doc_id": "15580078", "n_citations": 24, "n_key_citations": 2, "score": 0, "title": "Yield Prediction for Integrated Circuits Manufacturing Through Hierarchical Bayesian Modeling of Spatial Defects", "venue": "IEEE Transactions on Reliability", "year": 2011 } ]

[ { "abstract": "The 10 kV to 15 kV SiC MOSFET and 15 kV SiC IGBT are state of the art high voltage (HV) devices designed by Cree Inc. These devices are expected to increase the power density of converters and are expected to replace 4.5 kV/6.5 kV Si IGBTs. However, these are not commercially available. On the other hand low voltage (LV) 1.7 kV SiC MOSFET is commercially available, and it is replacing existing 1.7 kV Si IGBT and it can meet immediate need of medium or high voltage (MV or HV) converter applications with series connection of these devices and can replace existing 4.5 kV/6.5 kV Silicon (Si) IGBT. Therefore, 10 kV 15 kV SiC modules and series connected 1.7 kV SiC MOSFET will be competing with each other for MV and HV converter applications. Hence, to explore the capability of low voltage SiC devices for MV or HV applications, a HV switch (10 kV 15 kV) using the series connection of 1.7 kV/300 A SiC MOSFET modules has been investigated. For making HV switch using series connected 1.7 kV SiC MOSFET, a simple RC snubber method has been used for dynamic voltage sharing to offset the turn off delays due to mismatch of device characteristics and gate signals. Experimental switching characterization with different values of RC snubbers has been carried out, and a methodology has been outlined to find the optimal RC snubber which gives minimum voltage sharing difference, snubber losses and total semiconductor losses. In addition, experimental switching characterization of 10 kV 15 kV SiC modules is presented. Furthermore, a performance comparison of HV 10 kV 15 kV SiC modules and HV switch using series connected 1.7 kV SiC MOSFETs is presented in this paper.", "author_names": [ "Kasunaidu Vechalapu", "Subhashish Bhattacharya" ], "corpus_id": 7401760, "doc_id": "7401760", "n_citations": 28, "n_key_citations": 0, "score": 1, "title": "Performance comparison of 10 kV#x2013;15 kV high voltage SiC modules and high voltage switch using series connected 1.7 kV LV SiC MOSFET devices", "venue": "2016 IEEE Energy Conversion Congress and Exposition (ECCE)", "year": 2016 }, { "abstract": "A novel high speed SiC MOSFET driver with a low switch voltage stress is presented in this paper. In the proposed driver, a harmonic component is injected to the conventional class E inverter. Consequently, the class E driver proposed in this paper not only maintains the strong points of the conventional class E inverter, such as simple topology and high frequency high efficiency operation, but also has its own advantage of low switch voltage stress. The proposed class E driver is designed in this paper. Additionally, the PSpice simulation and laboratory experiment are carried out. It can be seen from the PSpice simulation and experimental results that all the switch voltage waveforms satisfy the zero voltage switching (ZVS) and zero derivative switching (ZDS) conditions. Therefore, the proposed class E driver is available in the high frequency and high efficiency applications. Moreover, a quite lower switch voltage stress is obtained in the proposed class E driver. The simulated and experimental results agreed with the theoretical one well. These results mentioned before demonstrated the proposed driver's validity.", "author_names": [ "Xiuqin Wei", "Yuchong Sun", "Hiroo Sekiya" ], "corpus_id": 53079764, "doc_id": "53079764", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "A Novel High Speed SiC MOSFET Driver with a Low Switch Voltage Stress", "venue": "2018 International Power Electronics Conference (IPEC Niigata 2018 ECCE Asia)", "year": 2018 }, { "abstract": "", "author_names": [ "Vechalapu Kasunaidu", "Bhattacharya Subhashish" ], "corpus_id": 117273198, "doc_id": "117273198", "n_citations": 11, "n_key_citations": 1, "score": 0, "title": "Performance comparison of 10 kV#x2013;15 kV high voltage SiC modules and high voltage switch using series connected 1.7 kV LV SiC MOSFET devices", "venue": "", "year": 2016 }, { "abstract": "Hybrid switch (HyS) consisting of the paralleled silicon carbide (SiC) metal oxide semiconductor field effect transistors (MOSFETs) and silicon (Si) insulated gate bipolar transistors (IGBTs) is proposed for high switching frequency and high efficiency at a reasonable cost. In this paper, a compact HyS three phase full bridge power module, rated at 1200 V/200 A, was fabricated in house and fully tested for the first time. To minimize HyS power loss, the turn on gate signals are applied to the Si IGBTs and the SiC MOSFETs simultaneously while a prior turn off period exists between the turn off gate signals of the Si IGBTs and the SiC MOSFETs. The prior turn off period is selected through the double pulse test. Based on the HyS power module, a 30 kW three phase voltage source inverter was developed.", "author_names": [ "Lei Li", "Puqi Ning", "Xuhui Wen", "Qiongxuan Ge", "Yaohua Li" ], "corpus_id": 169031825, "doc_id": "169031825", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "A 30kW Three Phase Voltage Source Inverter Based on The Si IGBT/SiC MOSFET Hybrid Switch", "venue": "2019 IEEE Applied Power Electronics Conference and Exposition (APEC)", "year": 2019 }, { "abstract": "The efficiency and power density of inverter can be significantly enhanced by employing wide band gap semiconductor devices Soft switched technology as well as magnetic integration technology. In this paper, first, a magnetically integrated soft switching inverter topology based on SiC MOSFET is proposed, and the zero voltage turn off loss of SiC MOSFET is researched emphatically. Then the influence of parasitic capacitance of SiC MOSFET on the realization of zero voltage switch and the method of extracting equivalent parasitic capacitance are accordingly discussed in detail. The dynamic loss model of inductor magnetic integration is constructed. The SiC MOSFET zero voltage switching condition is optimized, the voltage and current stress formulas of the device are also corrected, and more efficient circuit design parameters are obtained. Finally, the correctness and feasibility of the theoretical analysis are proved by the experimental prototype.", "author_names": [ "Lei Wang", "Donglai Zhang", "Jinpei Duan", "Jiannong Li" ], "corpus_id": 49537871, "doc_id": "49537871", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design of SiC MOSFET high power density soft switching inverter using integrated magnetic technique", "venue": "2018 13th IEEE Conference on Industrial Electronics and Applications (ICIEA)", "year": 2018 }, { "abstract": "SiC MOSFETs have demonstrated continued performance improvement and maturation in the areas of Gate oxide stability and reliability over the past years. While necessary, this alone is not sufficient to achieve reliable high voltage operation. In this paper, the design constraints impacting high voltage reliability and their impact on SiC MOSFET performance at useful operating conditions are discussed. Experimental results are demonstrated with industry benchmark, reliable operation of up to Tj=200degC with 1.2kV/25mOhm SiC MOSFETs and Tj=175degC, 1.7kV/450A all SiC MOSFET Dual Switch modules. Avalanche ruggedness of the high performance devices is also demonstrated with single pulse energy densities of 9 15J/cm2 recorded with Drain currents as high as ID= 90A for 0.2cm2 die.", "author_names": [ "Peter Almern Losee", "Alexander Viktorovich Bolotnikov", "L Yu", "Greg Dunne", "David Richard Esler", "Jeffrey Erlbaum", "Brian Lynn Rowden", "Arun Virupaksha Gowda", "Adam F Halverson", "Reza Ghandi", "Peter M Sandvik", "Ljubisa Dragoljub Stevanovic", "R Hristov" ], "corpus_id": 42686707, "doc_id": "42686707", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "SiC MOSFET design considerations for reliable high voltage operation", "venue": "2017 IEEE International Reliability Physics Symposium (IRPS)", "year": 2017 }, { "abstract": "High voltage SiC MOSFET modules are revolutionizing modern high power electronics owing to their high blocking voltage, low conduction resistance, and fast switching frequency. A 10 kV, 240 A SiC MOSFET module has recently become a candidate to build medium voltage converters. The MOSFET module comprises three independent submodules that can be configured as three phase legs, or one half bridge by paralleling. To maximize its performance, this paper presents a smart gate driver design for this particular semiconductor device. The design concentrates on a high current booster stage and a high bandwidth PCB embedded Rogowski switch current sensors for the paralleled submodules. The PCB layout has satisfied high voltage clearance and creepage standards. Finally, the booster current sharing and RSCS performance have been experimentally validated.", "author_names": [ "J Wang", "Slavko Mocevic", "Yue Xu", "Christina Dimarino", "Rolando Burgos", "Dushan Boroyevich" ], "corpus_id": 54456414, "doc_id": "54456414", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "A High Speed Gate Driver with PCB Embedded Rogowski Switch Current Sensor for a 10 kV, 240 A, SiC MOSFET Module", "venue": "2018 IEEE Energy Conversion Congress and Exposition (ECCE)", "year": 2018 }, { "abstract": "The medium voltage (MV) high speed drives are required for traction, wind energy, marine, aerospace, oil, and gas compressors applications. The MV converter must be able to switch at higher switching frequencies 5 kHz) to generate higher fundamental frequency AC input voltages for the motor 500 Hz) and thereby achieving high speed at the motor output 15000 rpm) This paper presents the series connection of 1.7 kV SiC MOSFET devices to enable simple two level MV converter for high speed drive and grid connected applications. Experimental switching characterization of a phase leg (one pole of a three phase converter) with the series connection of four devices per arm (or eight per leg) has been presented. It also presents the experimental results of a DC AC half bridge inverter with four devices in series per arm at 3kV dc bus, at different fundamental frequencies. It also includes the experimental endurance test results of phase leg (pole) in a DC DC converter at 100 kW, 3kV dc bus. Furthermore, it also presents the performance evaluation of a 3 phase voltage source inverter (VSI) efficiency using four series connected devices for 3.6 kV dc bus, 2.1 kV AC(L L) 720 kW output power and its comparison with single 6.5 kV Si IGBT.", "author_names": [ "Kasunaidu Vechalapu", "Samir Hazra", "Utkarsh Raheja", "Abhay Negi", "Subhashish Bhattacharya" ], "corpus_id": 34945276, "doc_id": "34945276", "n_citations": 18, "n_key_citations": 2, "score": 0, "title": "High speed medium voltage (MV) drive applications enabled by series connection of 1.7 kV SiC MOSFET devices", "venue": "2017 IEEE Energy Conversion Congress and Exposition (ECCE)", "year": 2017 }, { "abstract": "High voltage wide bandgap semiconductor devices such as the 15 kV SiC mosfet have attracted great attention because of their potential applications in high voltage and high frequency power converters. However, these devices are not commercially available at the moment, and their high cost due to expensive material growth and fabrication may limit their widespread adoption in the future. In this paper, a 15 kV 40 A SiC three terminal power switch, the Future Renewable Electric Energy Delivery and Management (FREEDM) supercascode, is reported for the first time, which is based on a series connection of 1.2 kV SiC power devices. Compared with the monolithic 15 kV SiC mosfet, the FREEDM supercascode demonstrates obvious advantages in cost and thermal conductivity. The design and voltage balancing mechanism of the FREEDM supercascode are introduced, and the performance including the voltage balancing, conduction characteristics over a wide range of temperatures, and dynamic switching performance, is analyzed. The FREEDM supercascode's low cost and excellent thermal dissipation capability will facilitate early applications of SiC in very high voltage and high frequency power converters.", "author_names": [ "Xiaoqing Song", "Alex Q Huang", "Soumik Sen", "Liqi Zhang", "Pengkun Liu", "Xijun Ni" ], "corpus_id": 28860230, "doc_id": "28860230", "n_citations": 22, "n_key_citations": 3, "score": 0, "title": "15 kV/40 A FREEDM Supercascode: A Cost Effective SiC High Voltage and High Frequency Power Switch", "venue": "IEEE Transactions on Industry Applications", "year": 2017 }, { "abstract": "The traditional wireless power transfer circuit uses the full bridge or half bridge inverter, which has complex circuit and control and low reliability. To solve these problems, a single switch LC resonant circuit is proposed, which is simple in structure and can realize zero voltage switching (ZVS) without the problem of shoot through. The circuit parameters and working process are modeled and analyzed. However, due to the influence of resonance, the common Si devices can not meet the demand because of the high blocking voltage of the switch. For this purpose, the circuit characteristics of SiC based devices are studied, and the differences of driving and temperature characteristics between SiC MOSFET and Si MOSFET are compared. Finally, a single switch wireless power transfer (WPT) platform based on SiC MOSFET is built, which proves that SiC devices have great advantages in the field of WPT.", "author_names": [ "Houji Li", "Chunfang Wang", "Yunrui Liu", "Rui Yue" ], "corpus_id": 208206338, "doc_id": "208206338", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Research on Single Switch Wireless Power Transfer System Based on SiC MOSFET", "venue": "IEEE Access", "year": 2019 } ]

[ { "abstract": "Abstract In this paper, one dimensional photonic crystal distributed feedback structures were chosen for simulating the photonic modes. The corresponding photonic bands were calculated by using a numerical method for solving the master equation, while the reflectivity spectra of the structures were simulated by using a rigorous coupled wave analysis method. By observing the variation of the photonic band diagram and the reflectivity spectrum versus different geometrical parameters, the variation of the photonic bands was detailedly studied. We observed two kinds of photonic modes: (i) the one related to the vertical structures, and (ii) the other related to the horizontal periodic structures. The detailed analysis of the optical modes was illustrated by proposing T E n X m B Z for indexing all transverse electric modes. An active layer coated on the distributed feedback structures plays an essential role in having radiative non leaky photonic modes. The coupling between these modes, giving to anti crossing, was also identified both by simulation and by modelling. This study can pave a way for further modelling optical modes in distributed feedback structures, and for selecting a suitable one dimensional photonic crystal for optoelectronic applications with a specific active semiconductor layer.", "author_names": [ "Ngoc Duc Le", "Thuat Nguyen-Tran" ], "corpus_id": 213875872, "doc_id": "213875872", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Simulation of coupling optical modes in 1D photonic crystals for optoelectronic applications", "venue": "", "year": 2020 }, { "abstract": "We present a detailed temperature and frequency dependence of the optical conductivity measured on clean high quality single crystals of URu2Si2 of ac and ab plane surfaces. Our data demonstrate the itinerant character of the narrow 5f bands, becoming progressively coherent as the temperature is lowered below a crossover temperature T*~75 K. T* is higher than in previous reports as a result of a different sample preparation, which minimizes residual strain. We furthermore present the density response (energy loss) function of this compound, and determine the energies of the heavy fermion plasmons with a and c axis polarization. Our observation of a suppression of optical conductivity below 50 meV along both the a and c axes, along with a heavy fermion plasmon at 18 meV, points toward the emergence of a band of coherent charge carriers crossing the Fermi energy and the emergence of a hybridization gap on part of the Fermi surface. The evolution towards coherent itinerant states is accelerated below the hidden order temperature THO=17.5 K. In the hidden order phase the low frequency optical conductivity shows a single gap at ~6.5 meV, which closes at THO.", "author_names": [ "Nimrod Bachar", "D A Stricker", "S R Muleady", "K Wang", "John A Mydosh", "Yun Kai Huang", "Dirk van der Marel" ], "corpus_id": 53314599, "doc_id": "53314599", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Detailed optical spectroscopy of hybridization gap and hidden order transition in high quality URu 2 Si 2 single crystals", "venue": "", "year": 2016 }, { "abstract": "Bulk undoped ZnS materials exhibit relatively bright yet diverse luminescence behavior, which has, in recent years, been attributed to intrinsic defects. However, the luminescence also resembles that of doped materials, implying a role of impurities. Luminescence features have also been attributed to oxygen impurities causing defect clusters or energy band anti crossing. Thus, this study couples optical and electrical techniques, such as band edge transmission, photoluminescence (PL) PL excitation, radioluminescence, thermoluminescence, optical deep level transient spectroscopy, and photoinduced current transient spectroscopy, to explore the identity of defect levels. ZnS materials studied are commercial single crystals made by physical vapor transport, high pressure Bridgman, and powder processing. These undoped bulk ZnS exhibit luminescence behavior similar to that of reported doped ZnS powders (10 4 to 10 2 mol. doping for luminescent materials) Dopants (such as Al, Cl, Cu, and Ag) are also commonly found impurities in ZnS; hence, it is reasonable to believe they have a role in the luminescence of nominally undoped ZnS. By comparing the variation in optical and electrical properties between samples to the processing method and the rich literature on intentionally doped ZnS, this study shows a possible dominant contribution of impurities and impurity containing defects on the luminescence of bulk \"undoped\" ZnS. Hence, there is no need to resort to complex mechanisms to explain the luminescence, but rather the metal and halide impurities and their defect complexes determine the main characteristics of luminescence in this wide bandgap semiconductor.Bulk undoped ZnS materials exhibit relatively bright yet diverse luminescence behavior, which has, in recent years, been attributed to intrinsic defects. However, the luminescence also resembles that of doped materials, implying a role of impurities. Luminescence features have also been attributed to oxygen impurities causing defect clusters or energy band anti crossing. Thus, this study couples optical and electrical techniques, such as band edge transmission, photoluminescence (PL) PL excitation, radioluminescence, thermoluminescence, optical deep level transient spectroscopy, and photoinduced current transient spectroscopy, to explore the identity of defect levels. ZnS materials studied are commercial single crystals made by physical vapor transport, high pressure Bridgman, and powder processing. These undoped bulk ZnS exhibit luminescence behavior similar to that of reported doped ZnS powders (10 4 to 10 2 mol. doping for luminescent materials) Dopants (such as Al, Cl, Cu, and Ag) are also commonl.", "author_names": [ "Muad Saleh", "Kelvin G Lynn", "Luiz G Jacobsohn", "John S McCloy" ], "corpus_id": 126572368, "doc_id": "126572368", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Luminescence of undoped commercial ZnS crystals: A critical review and new evidence on the role of impurities using photoluminescence and electrical transient spectroscopy", "venue": "Journal of Applied Physics", "year": 2019 }, { "abstract": "We theoretically demonstrate that tunable exceptional points (EPs) can be realized by using graphene embedded one dimensional (1D) photonic crystals with optical pumping in the terahertz (THz) frequency range. By tuning the Fermi level of graphene sheet, the energy band are altered significantly and the EP appears. In particular, multiple EPs at different frequencies can be selectively produced via subtly adjusting the band structure. Furthermore, topological features of these EPs, such as crossing and anti crossing of the real and imaginary parts of the eigenvalues, have been analyzed in detail. We expect that tunable EPs can provide an instructive method to design active optical devices based on photoexcited graphene sheets in the THz frequency range.", "author_names": [ "Shanshan Chen", "Weixuan Zhang", "Bing Yang", "Tong Wu", "Xiangdong Zhang" ], "corpus_id": 93001713, "doc_id": "93001713", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Tailoring exceptional points with one dimensional graphene embedded photonic crystals", "venue": "Scientific Reports", "year": 2019 }, { "abstract": "A two dimensional (2D) material, the holey 2D C2N (h2D C2N) crystal, has recently been synthesized. Here, we investigate the strain effects on the properties of this material by first principles calculations. We show that the material is quite soft with a small stiffness constant and can sustain large strains =12% It remains a direct gap semiconductor under strain, and the bandgap size can be tuned in a wide range as large as 1 eV. Interestingly, for biaxial strain, a band crossing effect occurs at the valence band maximum close to a 8% strain, leading to a dramatic increase of the hole effective mass. Strong optical absorption can be achieved by strain tuning with absorption coefficient ~106 cm 1 covering a wide spectrum. Our findings suggest the great potential of strain engineered h2D C2N in electronic and optoelectronic device applications.", "author_names": [ "Shan Guan", "Yingchun Cheng", "Chang Liu", "Junfeng Han", "Yunhao Lu", "Shengyuan A Yang", "Yugui Yao" ], "corpus_id": 123274062, "doc_id": "123274062", "n_citations": 94, "n_key_citations": 0, "score": 0, "title": "Effects of strain on electronic and optic properties of holey two dimensional C2N crystals", "venue": "", "year": 2015 }, { "abstract": "The CPGE spectrum and optical conductivity in RhSi are measured and discussed, comparing to theoretical predictions. Weyl semimetals are crystals in which electron bands cross at isolated points in momentum space. Associated with each crossing point (or Weyl node) is a topological invariant known as the Berry monopole charge. The circular photogalvanic effect (CPGE) whereby circular polarized light generates a helicity dependent photocurrent, is a notable example of a macroscopic property that emerges directly from the topology of the Weyl semimetal band structure. Recently, it was predicted that the amplitude of the CPGE associated with optical transitions near a Weyl node is proportional to its monopole charge. In chiral Weyl systems, nodes of opposite charge are nondegenerate, opening a window of wavelengths where the CPGE resulting from uncompensated Berry charge can emerge. Here, we report measurements of CPGE in the chiral Weyl semimetal RhSi, revealing a CPGE response in an energy window that closes at 0.65 eV, in agreement with the predictions of density functional theory.", "author_names": [ "Dylan Rees", "Kaustuv Manna", "Baozhu Lu", "Takahiro Morimoto", "Horst Borrmann", "Claudia Felser", "J E Moore", "Darius H Torchinsky", "Joseph Orenstein" ], "corpus_id": 220601224, "doc_id": "220601224", "n_citations": 45, "n_key_citations": 1, "score": 0, "title": "Helicity dependent photocurrents in the chiral Weyl semimetal RhSi", "venue": "Science Advances", "year": 2020 }, { "abstract": "Topological semimetals feature protected nodal band degeneracies characterized by a topological invariant known as the Chern number. The magnitude and sign of this invariant determine many of the exotic properties of such semimetals, including the number of topologically protected surface Fermi arcs, the number of chiral landau levels in the presence of a magnetic field, or the direction and strength of topological photocurrents in optical experiments. While formally the Chern number C can take any integer value, any nodal crossing with linear dispersion is expected to have at most |C|=4, realized in fourfold and sixfold nodes in spin orbit coupled, non symmorphic chiral crystals. Despite multiple recent photoemission studies of predicted material candidates, this maximal Chern number, measured by counting the number of Fermi arcs, has not yet been observed experimentally. Using angle resolved photoelectron spectroscopy and ab initio calculations, here we show that the chiral topological semimetal candidate PdGa displays the required multifold nodes, which are connected by long surface Fermi arcs. Due to large spin orbit coupling and the high crystallinity of our sample surfaces, we are for the first time able to resolve 4 independent Fermi arcs, proving experimentally that the observed multifold nodes which are a generic feature of many chiral metals display the maximal Chern number magnitude of 4. Furthermore, by comparing two crystals with mirrored crystal structure, we observe a reversal of the Fermi arc velocities, which demonstrates that the sign of the Chern numbers is tied to the handedness of the sample, which establishes an important control parameter for future experiments probing topological responses in chiral topological semimetals.", "author_names": [ "Niels B M Schroter", "Samuel Stolz", "Kaustuv Manna", "Fernando de Juan", "Maia G Vergniory", "Jonas A Krieger1", "Ding Pei", "Pavel Dudin", "Timur K Kim", "Cephise Cacho", "Barry Bradlyn", "Horst Borrmann", "Marcus Peter Schmidt", "Roland Widmer", "Vladimir N Strokov", "Claudia Felser" ], "corpus_id": 198147905, "doc_id": "198147905", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Observation and manipulation of maximal Chern numbers in the chiral topological semimetal PdGa", "venue": "", "year": 2019 }, { "abstract": "Optical phonon effects on the magnon resonance (FMR and AFMR) are shown to be negligible in ferromagnetic insulators and most antiferromagnets in present day laboratory fields (H 2 x 105 G) In these fields the magnon frequency lies lower than the optical phonon frequency so that the coupling is to a polarization mode which is mainly photon like. However, at the band edge, the wavelength dependence of the magnon and optical phonon dispersion may allow crossing in low fields. Also, in metamagnetic systems where the anisotropy field is much larger than the exchange field, the resonance in the paramagnetic phase may occur in a frequency range such that the polarization mode will contain a relative large fraction of optical phonons. The theory developed in this paper can also be applied to optical phonon spin resonance in paramagnetic salts. This type of resonance should occur in attainable magnetic fields for materials with large g factors. Die Wirkung optischer Phononen auf die Magnonresonanz (FMR und AFMR) in ferromagnetischen Isolatoren und in den meisten antiferromagnetischen Stoffen ist bei Feldern von H 2 x 105 G zu vernachlassigen. In diesen Feldern ist die Magnonfrequenz niedriger als die optische Phononenfrequenz, so das ihre Kopplung eine Polarisation ergibt, die hauptsachlich der durch Photonen verursachten ahnlich ist. An der Bandkante konnen sich jedoch in niedrigen Feldern die Wellenlangenabhangigkeit der Magnonen und optischen Phononendispersion kreuzen. Auch in metamagnetischen Systemen, bei denen das Anisotropiefeld sehr viel groser ist als das Austauschfeld, kann die Resonanz in der paramagnetischen Phase in einem solchen Frequenzbereich auftreten, das die Polarisation einen relativ grosen Anteil optischer Phononen enthalt. Die in dieser Arbeit entwickelte Theorie kann ebenfalls auf die optische Phonon Spin Resonanz in paramagnetischen Salzen angewandt werden. Dieser Resonanztyp sollte bei erreichbaren Feldern for Stoffe mit grosen g Faktoren auftreten.", "author_names": [ "T N Casselmann", "Harold N Spector" ], "corpus_id": 95017916, "doc_id": "95017916", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Interaction of Optical Phonons with Spin Waves in Ionic Crystals", "venue": "", "year": 1967 }, { "abstract": "Photonic crystals or photonic band gap materials are materials with modulated refraction index in the wavelength range. In the optical domain, the index modulation must be in the micrometric or sub micrometric range. The structures that we had fabricated are constituted by nanometric cylindrical air holes in thin films of arsenic sulphide chalcogenide (As2S3) and silicon. We obtained these two dimensional structures by a holographic technique that we developed in two steps using an argon ion laser. We also fabricated waveguides, couplers, or Y junctions incorporated into a two dimensional photonic crystal by combining the techniques of photolithography and holography. The functionality of these optical devices was also demonstrated at the wavelength of 1.55 mum. We also simulated the optical properties of these materials in order to understand how a homogenate medium can be profoundly modified when we structure periodically refraction index in the range of the wavelengths crossing it. Band diagrams were calculated for different structures, materials, refractive indices, dimensions, and polarizations. The method of Finite Difference Time Domain (FDTD) was also used to simulate the behavior of the 90deg waveguides, couplers, Y junctions, and a Mach Zehnder interferometer incorporated into a two dimensional structure of cylindrical air holes of AS2S3 or silicon. We particularly demonstrated the functionality of these optical components when operating at telecommunication wavelength at 1.55 mum.", "author_names": [ "Ismail Aboudihab", "Elmaati Ech-chamikh", "Abdelkader Outzourhit" ], "corpus_id": 23559848, "doc_id": "23559848", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Photonic crystal nanomaterials with arsenic sulphide chalcogenide and silicon for optical telecommunications", "venue": "2008 2nd ICTON Mediterranean Winter", "year": 2008 }, { "abstract": "Two dimensional photonic crystals have been fabricated by x ray lithography and reactive ion etching on an air/GaAs/AlGaAs asymmetric waveguide. The shape of the lattice unit cell has been varied by exploiting x ray diffraction effects and nonlinear response of resists during the development process. Rings with or without a central pillar have been fabricated with a resolution down to 50 nm. Lithographic details are described to show the accuracy of this fabrication technique. Optical characterization has been performed showing the presence of a well defined photonic band structure as well as band anti crossing. The results are discussed and compared with theoretical calculations of the photonic band dispersion. Structures with high dielectric fraction are shown to yield photonic modes with small line widths and low propagation losses. The reliability and the precise control of the fabricated sample structures make this lithographic method useful for a full investigation of optical properties on the dependence of the lattice unit cell shape.", "author_names": [ "Filippo Romanato", "Luca Businaro", "Enzo Di Fabrizio", "Adriana Passaseo", "Massimo de Vittorio", "Roberto Cingolani", "Maddalena Patrini", "Matteo Galli", "Daniele Bajoni", "Lucio Claudio Andreani", "Fabrizio Giacometti", "Massimo Gentili", "D Peyrade", "Yong Zhi Chen" ], "corpus_id": 56238550, "doc_id": "56238550", "n_citations": 19, "n_key_citations": 0, "score": 0, "title": "Fabrication by means of x ray lithography of two dimensional GaAs/AlGaAs photonic crystals with an unconventional unit cell", "venue": "", "year": 2002 } ]

[ { "abstract": "Rare earth oxides are usually widegap insulators like Y2O3 with closed shell trivalent rare earth ions. In this study, solid phase rock salt structure yttrium monoxide, YO, with unusual valence of Y2+ (4d1) was synthesized in a form of epitaxial thin film by pulsed laser deposition method. YO has been recognized as gaseous phase in previous studies. In contrast with Y2O3, YO was dark brown colored and narrow gap semiconductor. The tunable electrical conductivity ranging from 10 1 to 103 O 1 cm 1 was attributed to the presence of oxygen vacancies serving as electron donor. Weak antilocalization behavior observed in magnetoresistance indicated significant role of spin orbit coupling as a manifestation of 4d electron carrier.", "author_names": [ "Kenichi Kaminaga", "Ryosuke Sei", "Kouichi Hayashi", "Naohisa Happo", "Hiroo Tajiri", "Daichi Oka", "Tomoteru Fukumura", "Tetsuya Hasegawa" ], "corpus_id": 100487814, "doc_id": "100487814", "n_citations": 14, "n_key_citations": 1, "score": 1, "title": "A divalent rare earth oxide semiconductor: Yttrium monoxide", "venue": "", "year": 2016 }, { "abstract": "The recombination properties of silicon passivated with double layer dielectric films of yttrium oxide and dysprosium oxide have been investigated. The values of effective lifetime and surface recombination velocity of the nonequilibrium charge carriers on the interface of the rare earth elements/silicon oxide have been defined.", "author_names": [ "V A Rozhkov", "M A Rodionov", "A V Pashin", "A M Guryanov" ], "corpus_id": 36744628, "doc_id": "36744628", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Passivation of the silicon semiconductor devices and microwave frequency attachments with the double layer dielectric films from yttrium oxide and dysprosium oxide", "venue": "2004 14th International Crimean Conference \"Microwave and Telecommunication Technology\" (IEEE Cat. No.04EX843)", "year": 2004 }, { "abstract": "This paper reports an investigation of the electrophysical properties of metal dielectric semiconductor varicaps with an yttrium oxide dielectric, prepared by resistive vacuum evaporation of the rare earth metal with subsequent thermal oxidation of the film in air at 500 550 degC. It is found that the electrical conductivity of the samples follows the Poole Frenkel law. High frequency capacitance voltage characteristics are used to determine the specific capacitance of the dielectric, C0=0.027 0.03 mF/cm2, the slope of the capacitance voltage characteristic, dC/dV=35 40 pF/V, the fixed charge in the dielectric, Qf=(1.7 2.7)x10 8 C/cm2, and the density of surface states at the flat band potential, Nss=(1 2)x1011 cm 2*eV 1. The capacitance tuning range factor for the metal dielectric semiconductor varicaps is 2.5 3. These structures are shown to be applicable as metal dielectric semiconductor varicaps with a low control voltage and a high quality factor.", "author_names": [ "V A Rozhkov", "A Yu Trusova" ], "corpus_id": 120222525, "doc_id": "120222525", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Silicon metal dielectric semiconductor varicaps with an yttrium oxide dielectric", "venue": "", "year": 1997 }, { "abstract": "Synchrotron radiation photoemission studies show that thin Yb overlayers (0.3 4.1) monolayers) enhance the oxidation of GaAs(110) surfaces. The magnitude of the promotion effect varies as a function of Yb coverage. The oxidation reaction products involve several nonequivalent oxidation states of As and Ga. The specific catalytic activity of the pure divalent Yb overlayers in promoting GaAs oxidation appears lower than that of Sm overlayers containing both Sm2+ and Sm3+ species. The spectroscopic signature of the oxidation reaction products, instead, is compellingly similar for the two rare earth promoters. We propose that the oxidation promotion mechanism is related, in both cases, to the decomposition of metal/semiconductor interface reaction products upon exposure to oxygen, and that the rare earth atomic valence has only a limited influence on the promotion mechanism.", "author_names": [ "S Chang", "Pecoraro Raymond Philip", "A Wall", "X Yu", "Alfonso Franciosi" ], "corpus_id": 95343223, "doc_id": "95343223", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Rare earth promoters of semiconductor oxidation: The case of GaAs(110)/Yb", "venue": "", "year": 1990 }, { "abstract": "Waste electrical and electronic equipment (WEEE) has increased in recent decades due to the continuous advancement of technology in the modern world. These residues have various metals that are found in concentrations that make their recovery profitable. A group of metals of interest are the rare earths such as europium and yttrium, as well as semiconductors such as indium. Yttrium was recovered from cathode ray tubes that were manually dismantled. The resulted powder was leached with HNO3, and then the solution was submitted to solvent extraction with di (2 ethylhexyl) phosphoric acid (DEHPA) using n heptane as a diluent. For re extraction, HNO3 was used again, and yttrium was precipitated by adding four times the stoichiometric amount of oxalic acid, reaching 68% yttrium purity. Indium was recovered from the liquid crystal display (LCD) screens for which the pulverized material was leached with H2SO4. Then, the indium sulfate was subjected to solvent extraction using DEHPA as an extractant, and diesel as a diluent. The re extraction was carried out again with H2SO4, and the obtained acid solution was evaporated until the indium precipitated, reaching a recovery of 95% The investigations that were carried out show that it is feasible to recover these metals in the form of oxides or phosphates with high commercial value.", "author_names": [ "Ernesto de la Torre", "Estefania Vargas", "Cesar A Ron", "Sebastian Gamez" ], "corpus_id": 139677410, "doc_id": "139677410", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Europium, Yttrium, and Indium Recovery from Electronic Wastes", "venue": "", "year": 2018 }, { "abstract": "Solar energy represents an abundant (1000 W*m 2) and seemingly cheap source of energy. One way to tap it is to transform light into electricity with photovoltaic devices. Single junction solar cells presently reach 32% conversion yield under 1 sun illumination while multijunction devices irradiated by concentrated light can reach 44% One major problem encountered when trying to increase the conversion efficiency lies in the spectral mismatch between the absorption spectrum of the semiconductor and the solar emission spectrum. As a remedy, wavelength converting materials are being developed and because solar cells perform best in a relatively narrow spectral range which depends on their bandgap energy, lanthanide luminescent divalent and trivalent ions are particularly well suited for this purpose. In addition non luminescent ions feature special crystallographic and conduction properties which make them invaluable in lattice matched multijunction devices. In this chapter, the performances of rare earth ions in downconverting, downshifting, and upconverting materials embedded into the architecture of luminescent solar concentrators, silicon solar cells, semiconductor photovoltaic devices, and dye sensitized solar cells (DSSCs) is comprehensively and critically reviewed. Other contributions, e.g. as scattering layers and as modifiers of the bandgap of titanium oxide in DSSCs, or to the powering of in vivo nanorobots are likewise described. Finally a general assessment is made and improvements on the order of +5 absolute% in conversion yield are predicted provided fully optimized materials can be tailored.", "author_names": [ "Jean-Claude G Bunzli", "Anne-Sophie Chauvin" ], "corpus_id": 93617332, "doc_id": "93617332", "n_citations": 70, "n_key_citations": 0, "score": 0, "title": "Lanthanides in Solar Energy Conversion", "venue": "", "year": 2014 }, { "abstract": "Title of Document: EFFECTS OF COMPLEXATION WITH THE SIDEROPHORE DESFERRIOXAMINE B ON TRANSITION METAL REMOVAL FROM SEAWATER Emily A. Christenson, Master of Science, 2013 Directed By: Associate Professor, Johan Schijf, Marine Environmental and Estuarine Science Complexation of transition metals with strong organic ligands of unknown structure and origin plays an important role in their behavior and distributions in seawater. I present here a series of stability constants for complexes of several transition metals with the trihydroxamate siderophore desferrioxamine B (DFOB) representative of a class of small organic ligands that are exceptionally selective for Fe(III) and found in open ocean surface waters at low picomolar concentrations. Stability constants for DFOB complexes with divalent metals are similar to conditional constants that have been measured in seawater for highly metal specific, but unidentified organic ligands. Titration data indicate that free Hg forms a very stable complex with DFOB, however the more toxic methylmercury cation does not. A revised scavenging model for yttrium and the rare earth elements suggests that their removal from seawater is dominated by sorption onto Mn oxides, yet not significantly influenced by biogenic silica or calcite. EFFECTS OF COMPLEXATION WITH THE SIDEROPHORE DESFERRIOXAMINE B ON TRANSITION METAL REMOVAL FROM SEAWATER", "author_names": [ "Emily A Christenson" ], "corpus_id": 92115410, "doc_id": "92115410", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "EFFECTS OF COMPLEXATION WITH THE SIDEROPHORE DESFERRIOXAMINE B ON TRANSITION METAL REMOVAL FROM SEAWATER", "venue": "", "year": 2013 }, { "abstract": "The crystal structure parameters of solid solutions YBaCuFe1 3 xCoxO5 (0 x 1) were determined, and their thermal stability, thermal expansion, conductance, thermoelectromotive force, dielectric properties, and magnetic sensibility were studied. At present, layered perovskite like oxides A`A\"B2O5.5+d (A` is Y or rare earth element; A\" is alkaline earth element; B is 3d metal) attract appreciable interest. One of such compounds is yttrium barium ferrocuprate YBaCuFeO5 d, which was described for the first time in [1] The compound YBaCuFeO5 has a tetragonal unit cell with the parameters a 0.3867 and c 0.7656 nm (space group P4mm, z 1) [2] though, according to [3] this compound belongs to space group P4/mmm. At room temperature, YBaCuFeO5 is antiferromagnetic (Neel temperature TN is 4403475 K) its magnetic structure changes at 1903240 K [335] (a commensurate 6 incommensurate phase transition) The compound YBaCuFeO5 is a p type semiconductor [6] and shows anomalies of dielectric properties near 460 and 560 K [7] The effect of iron replacement by nickel on the structure and properties of YBaCuFe13x NixO5 solid solutions was examined in [6] Solid solutions YBaCu13xCoxFeO5 +d, YBaCu13xFexFeO5 d, and YBaCuFe1 3 xCoxFeO5 d were obtained in [8] and their thermal stability in various gaseous media was examined in [9] Here we report data on the crystal structure, thermal expansion, and electrophysical and magnetic properties of solid solutions YBaCuFe1 3 xCoxO5.", "author_names": [ "Ekaterina A Chizhova", "A I Klyndyuk", "Leonid Bashkirov", "Gennady Petrov", "K I Yanushkevich" ], "corpus_id": 92186597, "doc_id": "92186597", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Structure and Properties of Solid Solutions in the System YBaCuFeO 5 YBaCuCoO 5", "venue": "", "year": 2005 }, { "abstract": "We report about the optical reflectivity of TmSeand of the metallic phase of SmS in the photon energy range between 0.03 eV and 12 eV. From the differentially measured lattice constants of both semiconducting and metallic SmS and from the plasma frequency, we deduce an intermediate Sm valence of 2.85 2.9 in the high pressure phase. 'Also in TmSe, we conclude from the plasma frequency the existence of about one delocalized electron per Tm ion. In the last few years, the discussion about mixed valence compounds opened a very interesting field of solid state physics [I] Although the concept of variable valence is well known in chemistry, it has extraordinary consequences in connection with Rare Earth (RE) elements and compounds and their physical properties. As is well known, many of the RE ions appear not only in the trivalent oxidation state, but also in the'divalent or tetravalent one, and the occupation number of the 4if shell changes concomitantly. In some compounds, the RE ions appear a priori in different valencies and the different valent ions can be situated on equivalent or inequivalent lattice sites. In the first case. the excess 4 f electrons of the lower valent cation move through the cation sublattice by means of a temperature activated hopping (Sm,S4, Eu,S, [2 41, at least above the charge ordering transition 5 and any cation experiences a fluctuating valence, whereas in the latter case the different valencies are static and regularly distributed (Eu,04, [6] But in this paper, we are dealing with a third group of mixed valence compounds, where every cation has a hybridized configuration in the form 4 fn 4 fn (5 d 6 s) It depends now only upon the hybridization energy relative to the energy differences between the various excited states involved in an experiment, whether one speaks of an intermediate valence [I] Assuming a typical hybridization energy of to lo eV e. g. a MBssbauer measurement (eV) shows an isomer shift corresponding to an intermediate valence, while photoemission (XPSor UPS) measurements (10 eV) detect a coexistence of two electronic configurations with integer number of 4 f electrons. One of the most important problems is to determine the degree of valence mixing. In principle, different methods seem to be appropriate, but every one has its own problems. For example, XPS and UPS compare the intensities of the typical 4 f multiplets in the energy distribution of emitted photoelectrons, while the Mossbauer effect and the method of the chemical shift of corelevels [7] measure spectral shifts. In the latter two procedures, a simple interpolation between the frequencies of non fluctuating ionic compounds yields the degree of mixing but covalency effects are rather difficult to estimate. An other easy way is the comparison of the measured lattice constant with the limiting values expected for pure valencies. This is based on the fact, that the ionic radii of different valent RE ions change up to 10 The validity is restricted by both principal and practical dificulties. First of all, a linear interpolation seems not to be suitable, because the potential energy distribution in general is not the same for different valent ions, moreover, the lattice constant is similarly influenced also by stoichiometry. In consequence of all these special pecularities it is desirable to have a further instrument at one's disposal to determine the degree of valence mixing. The hybridization between 4 fn and 4 fn (5 d 6 s) is equivalent to a partial delocalization of an electron, or in the language of the energy band theory, a change of the effective mass m* of the electron. The light electrons now are able to build up a common collective plasma oscillation, its frequency being given by the electron density and m* This coherent movement only arises, if the plasmon energy is larger than the hybridization energy. Thus, a measurable plasma resonance yields an Article published online by EDP Sciences and available at http:/dx.doi.org/10.1051/jphyscol:1976446 C4 268 B. BATLOGG, A. SCHLEGEL AND P. WACHTER upper limit for the hybridization energy together with the effective mass and the density of electrons. The effective optical mass can be determined for instance with cyclotron resonance measurements. SmS is at normal conditions a semiconductor with a narrow energy gap (0.1 eV) between the occupied and localized 4 f6 states and the 5 d conduction band. It crystallizes in the rock salt structure and Sm is divalent. Rising pressure increases the crystal field splitting of the 5 d conduction band, keeping the center of gravity constant [8] and an isostructural first order phase transition with typical hysteresis occurs [9, 101. The metallic high pressure phase has been the subject of many investigations and from lattice constant, specific heat [ll] susceptibility [I21 and Mossbauer isomer shift [13] an intermediate valence has been deduced. We obtain the golden, metallic phase by polishing black semiconducting crystals. Chemical analysis yields stoichiometry with a precision of 0.5 and a comparison of the room temperature electrical conductivity (37 R cm l) with systematic investigations of the el. conductivity as function of chemical composition [14] confirms the good quality of the samples used. The first experiment we have performed on such a black crystal with a 'golden surface, was a X ray Bragg reflection. Surprizingly, we found two sets of reflexes with equal line width and we computed lattice constants of 5.97 A and 5.68 A, corresponding doubtlessly to the semiconducting and the metallic phase. Moreover, this important result shows, that the surface is single crystalline and it supports our measurements as being representative for single crystals under hydrostatic pressure. This experiment has the additional advantage of every differential method and is free of calibration problems. Now we are able to estimate the degree of valence mixing using the new lattice constant of 5.68 A. In absence of a better way, also we interpolate linearly between the expected value of the Sm3'S and the known one of Sm2'S and obtain an intermediate valence of 2.85 for Sm. However, in a recent work on SmS films it is reported about the existence of SmS films with every lattice constant between 5.62 and 5.97 A [15] As mentioned above, the plasma resonance of the light electrons gives information about the degree of valence mixing. We have measured the reflectivity of the metallic phase of SmS in the photon energy range between 0.03 eV and 12 eV, and in function of temperature (4.2 K to 300 K) The spectrum in figure 1 behaves normal as known from Gdand La chalcogenides [I51 with interband transitions above 3 eV and plasma oscillation below 3 eV. On cooling to 4.2 K, the reflectivity edge, producing the golden colour, remains at the same energy and becomes only somewhat steeper as expected. In contrast, the reflectivity edge in chemically collapsed Sm, ,Yo ,S shifts toward lower energies with decreasing temperature [17] and this is the first decesive hint that chemical alloying is not equivalent to external mechanical FIG. 1. Optical reflectivity of metallic SmS at 300 K (full line) and at 4.2 K (dotted line) pressure alone. By means of a Kramers Kronig analysis, we derived the complex dielectric function 0 ie2(w) The real part increases from very large negative values at low energy and crosses the real axis at 2.45 eV. The positive slope of E, and a maximum in the energy loss function E E 8; at this energy (Fig. 2) indicate a longitudinal excitation mode, the coupled plasmon mode. The interaction between the free electrons is slightly screened by the presence of interband transitions and the unperturbed resonance will be shifted to higher energy. 0 2 4 6 Photon Energy (eV) FIG. 2. Energy loss function of metallic SmS and of TmSe. DEGREE OF VALENCE MIXING IN THE METALLIC PHASE OF SmS AND IN TmSe C4 269 With a procedure described elsewhere [18] we decompose 8, into contributions from bound 8' and free carriers 8: NOW, the intersection point of ef with the real axis at 4.6 eV gives the energy of the unperturbed plasma frequency o, of the conduction electrons. Because o, the density of carriers N and the effective mass m\" are connected by we can immediately derive the number of light electrons per cation. Many other similarities in the electronic structure encourage us, to assume the same light effective mass in GdS (m* 1.3 m) 1161, because it is the same band with nearly the same degree of filling. Using the relation above, we obtain 0.9 electrons with m* 1.3 m per Sm and an intermediate valence of 2.9. The agreement with the value deduced from the differentially measured lattice constant is satisfactory. The intermediate valence of Sm in pure SmS, determinated on single crystalline samples with stoichiometric composition therefore is doubtless higher (2.85 2.9) than in chemically collapsed systems (2.7) Also the isomer shift measurements by Coey et al. [13] on high pressure SmS and on Smo.77Yo,,S clearly show a difference in the spectra and confirm, that chemical doping is not equivalent to external pressure", "author_names": [ "Bertram J Batlogg", "A Schlegel", "Peter Wachter" ], "corpus_id": 44148555, "doc_id": "44148555", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "DEGREE OF VALENCE MIXING IN THE METALLIC PHASE OF SmS AND IN TmSe", "venue": "", "year": 1976 }, { "abstract": "In this study, we demonstrate that introducing of less electronegative R elements (R La or Pr) into the Bi O charge reservoir layer of BiCuSeO enhances the chemical bond ionicity and leads to an increase of both, the charge carrier concentration and the effective mass. Although the charge carrier mobility decreases upon Bi3+ to R3+ substitution, the electronic transport properties are significantly improved in a broad temperature range from 100 K to 800 K. In particular, the electrical resistivity decreases by two times, while the Seebeck coefficient drops from 323 mV K 1 to 238 mV K 1 at 800 K. Thus, a power factor of nearly 3 mW cm 1 K 2 is achieved for Bi0.92La0.08CuSeO sample at 800 K. Meanwhile, a noticeable decrease of the lattice thermal conductivity is observed for the doped samples, which can be attributed to the enhanced point defect scattering mostly originated from atomic mass fluctuations between R and Bi. Ultimately, a maximum zT value of nearly 0.34 at 800 K is obtained for the Bi0.92La0.08CuSeO sample, which is ~30% higher than that of pristine BiCuSeO. Introduction The oxyselenides family MCuSeO, where M trivalent cation such as Bi or rare earth elements, was reported for the first time in 1993 by Boris A. Popovkin group.1,2 The related compounds (so called 1111 phases) crystallize in the tetragonal layered ZrCuSiAs structure type with P4/nmm space group and two formula units per cell. The crystal structure is composed of alternately stacked along the c axis insulating (M2O2) layers with ionic bonds and conducting (Cu2Se2) layers with covalent bonds, as shown in Fig. 1a.1,3,4 Generally, the RCuSeO (R rare earth) are wide gap p type semiconductors (Eg ~3 eV) with the valence band maximum (VBM) and the conduction band minimum (CBM) at the G point of the Brillouin zone.5 8 In both cases, RCuSeO and BiCuSeO, the VBM is composed of the hybridized Cu 3d and Se 4p orbitals.9 BiCuSeO is also p type semiconductor, but with a narrow bandgap of about 0.8 eV. Such evolution in the band structure originates from the presence of Bi 6p orbitals at the bottom of the conduction band.5,10,11 To date, BiCuSeO oxyselenides have attracted considerable attention and were intensively studied as promising Pb free families of thermoelectric materials owing to their intrinsically low thermal conductivity and relatively high Seebeck coefficient. The remarkable thermoelectric performance was reported for Ba doped BiCuSeO with the dimensionless figure of merit zT value ~1.4 at 923 K.12,13 Here zT is defined as zT S2 s T k 1, where S, s, T and k are the Seebeck coefficient, electrical conductivity, absolute temperature, and total thermal conductivity, respectively.14,15 The charge carrier concentration in BiCuSeO can be increased using partial substitution of Bi3+ by divalent or monovalent ions inducing extra holes. However, the intrinsically low charge carrier mobility, which is usually below ~20 cm2 V 1 s 1 for pristine BiCuSeO, is deteriorated to less than 2 cm2 V 1 s 1 by heavy doping with alkali or alkaline earth elements, which greatly hampers the further possible electrical transport properties improvement.9 Thus, another strategy, such as band structure engineering along with tuning of chemical bonding is utilized to decouple the trade off between the charge carrier concentration and their mobility.16 19 The charge carries in BiCuSeO are predominantly scattered by acoustic phonons and thus their mobility is closely related to the effective mass and the carrierphonon coupling.20,21 At the same time, the effective mass, m* is largely determined by the ionicity (covalence) of the corresponding chemical bond. Since the electronegativity reflects the tendency of an atom to attract an electron density, the increase in bond ionicity will decrease the overlapping of the shared electron densities leading to increased effective mass. Furthermore, partial substitution of Bi by less electronegative atoms can lead to more electrons being released into the system, which may contribute to the enhanced charge carrier concentration. Besides, the Cu vacancies play an essential role in the BiCuSeO electrical transport and are believed to be the origin of the p type conduction in the nominally undoped BiCuSeO.9,10,22 Indeed, it was reported that the copper vacancies seem to be thermodynamically favored due to their low formation energy23 26 relative to other types of intrinsic defects, which results in unintentional doping of nominally undoped MCuSeO based compounds due to the presence of a faint amount of copper vacancies5,11,27 according to Kroger Vink notation:28 X 0 Cu Cu surface Cu Cu V h (1) Thus, the charge carrier concentration and the related electrical conductivity values strongly depend on the precise chemical composition, especially on the presence a National University of Science and Technology MISIS, 119049 Moscow, Russia b Ioffe Institute, 194021 St. Petersburg, Russia E mail: novitskiy@misis.ru c The University of New South Wales, 2052 Sydney, Australia d Sobolev Institute of Geology and Mineralogy, 630090 Novosibirsk, Russia e L.N. Gumilyov Eurasian National University, 010000 Nur Sultan, Kazakhstan Present address: Lulea University of Technology, 97187 Lulea, Sweden Electronic Supplementary Information (ESI) available PREPRINT Novitskii et al. April 21, 2021 2 of vacancies, and can vary from ~0.1 O 1 cm 1 to more than 1 O 1 cm 1 at room temperature and exhibit degenerate as well as nondegenerate behavior with temperature.10,11,23,27,29 32 Here we demonstrate experimentally that the carrier concentration and effective mass can be noticeably increased by doping with less electronegative rare earth elements (La or Pr) at the Bi site in (Bi2O2) layers. Consequently, a maximum zT of ~0.34 at 800 K can be achieved for the Bi0.92La0.08CuSeO sample, ~30% enhancement as compared with that of the pristine sample. The experimental study was combined with ab initio density functional theory (DFT) calculations in order to clarify the effect of band structure evolution with doping on transport properties. Experimental details The starting chemicals for the synthesis of Bi1 xRxCuSeO (R La or Pr, x 0 0.08) were the fine commercial powders of Bi2O3 (99.5% Reachem) La2O3 (99.99% Rare Metallic) Pr2O3 (99.99% Shin Etsu Chemical) and Bi 99.95% Component Reaktiv) Se (99.90% Reachem) Cu 99.5% Rushim) The powders were weighed, according to the stoichiometric ratio, and then ball milled (BM) in an argon atmosphere at 400 rpm for 8 hours (planetary micro mill Pulverisette 7 premium line, Fritsch, Germany) The obtained mixture was coldpressed into pellets and sealed in an evacuated to 10 3 Torr silica tubes. The tubes were heated to 573 K with the rate of 5 K min 1 and held for 8 hours, then cooled to room temperature. The resulting specimens were crushed, ground, and ball milled again in argon at 400 rpm for 4 hours, cold pressed, and resealed in another evacuated quartz tubes. The samples were annealed at 973 K for 12 hours. The pellets were ball milled one more time in argon at 300 rpm for 8 hours. For ball milling processing, the zirconium oxide vials with a volume of 45 ml and balls with a diameter of 5 mm were used. In order to obtain bulk samples, the powders were densified by spark plasma sintering (Labox 650, Sinter Land, Japan) at 973 K for 5 minutes under uniaxial pressure of 50 MPa. The cylindrical specimens of 12.7 mm in diameter and 10 mm high were annealed at 973 K for 6 hours in an argon atmosphere. For comparative analysis, one pristine BiCuSeO sample was prepared without using the ball milling during powder preparation, with hand grinding instead. More details on the experimental procedure can be found in the electronic supporting information file (ESI) The synthesized samples were characterized by a range of techniques, including X ray fluorescence (XRF) powder X ray diffraction (XRD) scanning electron microscopy (SEM) energy dispersive X ray spectroscopy (EDS) Brunauere Emmette Teller (BET) surface area analysis, and various physical measurements, such as the electrical and thermal conductivities, Seebeck coefficient and Hall constant measurements. The effective average particle size of the synthesized powders was calculated as D 6d 1 A 1 (where d is the density) from the low temperature adsorption isotherm measurements of the specific surface area, A, using a Nova 1200e analyzer (Quantachrome Instruments, USA) The XRF spectra were taken with a ZSK Primus II spectrometer (Rigaku, Japan) X ray diffraction data were collected over the angular range 20 2th (deg) 80, on a Miniflex 600 2 diffractometer (Rigaku, Japan) using CoKa radiation (l 1.7903 A) at room temperature. Rietveld refinement was performed using PDXL software (Rigaku, Japan) SEM and EDS were performed using Vega 3SB scanning electron microscope (Tescan, Czech Republic) in conjunction with an EDS detector (x act, Oxford Instruments, UK) Temperature dependencies of the electrical resistivity and the Seebeck coefficient were simultaneously measured with high resolution (temperature increment ~1 K) by the standard 4 probe and differential methods, respectively, under He atmosphere using a homemade system.33 The uncertainty of the Seebeck coefficient and the electrical resistivity measurements is 5% 0.5 mV/K and 2% respectively. Thermal conductivity, k, was determined from thermal Figure 1. (a) Crystal structure of the BiCuSeO and (b) XRD patterns of the Bi1 xRxCuSeO (R La or Pr, x 0 0.08) +Pristine BiCuSeO sample prepared without ball milling. PREPRINT Novitskii et al. April 21, 2021 3 diffusivity measurements using relationship k kh*Cp*d, where kh is the thermal diffusivity coefficient, Cp is the specific heat capacity. The relative bulk density was measured by the Archimedes method. Temperature dependencies of the thermal diffusivity were measured by the laser flash diffusivity metho", "author_names": [ "Andrei Novitskii", "Illia Serhiienko", "Sergey Novikov", "Ye Zh Ashim", "Mark V Zheleznyi", "Kirill Kuskov", "Daria Pankratova", "P P Konstantinov", "Andrei Voronin", "Oleg A Tretiakov", "Talgat M Inerbaev", "A Burkov", "Vladimir V Khovaylo" ], "corpus_id": 233324425, "doc_id": "233324425", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Tailoring the transport properties of BiCuSeO oxyselenides by increasing bond ionicity", "venue": "", "year": 2021 } ]

[ { "abstract": "Condition monitoring (CM) has already been proven to be a cost effective means of enhancing reliability and improving customer service in power equipment, such as transformers and rotating electrical machinery. CM for power semiconductor devices in power electronic converters is at a more embryonic stage; however, as progress is made in understanding semiconductor device failure modes, appropriate sensor technologies, and signal processing techniques, this situation will rapidly improve. This technical review is carried out with the aim of describing the current state of the art in CM research for power electronics. Reliability models for power electronics, including dominant failure mechanisms of devices are described first. This is followed by a description of recently proposed CM techniques. The benefits and limitations of these techniques are then discussed. It is intended that this review will provide the basis for future developments in power electronics CM.", "author_names": [ "Shaoyong Yang", "Dawei Xiang", "Angus T Bryant", "Philip A Mawby", "Li Ran", "Peter J Tavner" ], "corpus_id": 22420542, "doc_id": "22420542", "n_citations": 713, "n_key_citations": 30, "score": 1, "title": "Condition Monitoring for Device Reliability in Power Electronic Converters: A Review", "venue": "IEEE Transactions on Power Electronics", "year": 2010 }, { "abstract": "In terms of power supplies and power conversion, power electronics based converters have their own advantages. Proper condition monitoring for power electronic converter has become necessary which is now in incipient stage. This paper includes different kinds of failure modes associated with power electronics at the converter as well as device level and recent Condition Monitoring (CM) techniques to detect those faults at the earliest stage. Proper reliability improvement has to be performed on power electronic systems so that they could be more resistive to different aspects such as safety, cost and availability. Power semiconducting devices are considered to be the most sensitive part of the power electronic systems and the main causes of stresses on these devices could be initiated due to the atmospheric conditions as well as short duration heavy loads, which should be considered during power electronic system design and normal operation as the consequences of these can't be felt at the initial stage which demands conservative converter design.", "author_names": [ "Sai Srinivas Manohar", "Animesh Sahoo", "Aravinth Subramaniam", "Sanjib Kumar Panda" ], "corpus_id": 39821365, "doc_id": "39821365", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Condition monitoring of power electronic converters in power plants A review", "venue": "2017 20th International Conference on Electrical Machines and Systems (ICEMS)", "year": 2017 }, { "abstract": "The investigation shows that power semiconductor devices are the most fragile components of power electronic systems.Improving the reliability of power devices is the basis of a reliable power electronic system, and in recent years, many studies have focused on power device reliability.This paper describes the current state of the art in reliability research for power semiconductor devices, mainly includes failure mechanisms,condition monitoring, lifetime evaluation and active thermal control.Among them,condition monitoring technology are classified and summarized by the failure mechanism and the change rules of characteristic quantities; The method of lifetime estimation isillustrated from the practical point of view;Methods of active thermal control are classified and summarized from the two ideas of reducing loss and loss compensation which are refined by the principle of realization. At last, this paper draws the existing problems and challenges of power devices reliability studies.", "author_names": [ "Bo Wang", "Jie Cai", "Xiong Du", "Luowei Zhou" ], "corpus_id": 54667815, "doc_id": "54667815", "n_citations": 37, "n_key_citations": 0, "score": 0, "title": "Review of power semiconductor device reliability for power converters", "venue": "", "year": 2017 }, { "abstract": "Condition and health monitoring (C&HM) is an effective means of improving the availability and controlling the life time cost of power electronic components, converters and systems. Many solutions have been developed, but their adoption in industrial applications is still scarce. This paper intends to the reasons for this by favouring Industrially motivated research. Advanced C&HM techniques that open new possibilities for industrialisation are reviewed. Their potential, limitations and implementation are outlined and critically assessed with the goal of benefiting both industry applications and research. A significant part of the paper is dedicated to C&HM for power devices and modules, responding to the general perception that they are the least reliable with topics such as prognostics based qualification for power electronics to predict the future reliability of the products and remaining useful lifetime methods. In situ methods for estimation of junction temperature and use of temperature sensitive electrical parameters are summarised within the framework of C&HM. The C&HM of other notoriously unreliable components, such as capacitors and batteries are also addressed.", "author_names": [ "Stefan V Mollov", "Frede Blaabjerg" ], "corpus_id": 116595687, "doc_id": "116595687", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Condition and Health Monitoring in Power Electronics", "venue": "", "year": 2018 }, { "abstract": "The urgency for an increased capacity boost bounded by enhanced reliability and sustainability through operating cost reduction has become the major objective of electric utilities worldwide. Power electronics have contributed to this goal for decades by providing additional flexibility and controllability to the power systems. Among power electronic based assets, high voltage dc (HVdc) transmission systems and flexible ac transmission systems (FACTS) controllers have played a substantial role on sustainable grid infrastructure. Recent advancements in power semiconductor devices, in particular in voltage source converter based technology, have facilitated the widespread application of HVdc systems and FACTS devices in transmission networks. Converters with larger power ratings and higher number of switches have been increasingly deployed for bulk power transfer and large scale renewable integration increasing the need of managing power converter assets optimally and in an efficient way. To this end, this paper reviews the state of the art of asset management strategies in the power industry and indicates the research challenges associated with the management of high power converter assets. Emphasis is made on the following aspects: condition monitoring, maintenance policies, and ageing and failure mechanisms. Within this context, the use of a physics of failure based assessment for the life cycle management of power converter assets is introduced and discussed.", "author_names": [ "Tibin Joseph", "Carlos Ernesto Ugalde-Loo", "Jun Liang", "Paul F Coventry" ], "corpus_id": 4998771, "doc_id": "4998771", "n_citations": 22, "n_key_citations": 1, "score": 0, "title": "Asset Management Strategies for Power Electronic Converters in Transmission Networks: Application to Hvdc and FACTS Devices", "venue": "IEEE Access", "year": 2018 }, { "abstract": "With the extensive use of power converters in modern hybrid vehicles, rises the need for efficient methods of condition monitoring and fault diagnosis to ensure the reliability of the automotive electrical power system. This paper is a technical review that studies power electronic devices and converters used in hybrid electric vehicles with a description of possible faults and a highlight on the recent progress of condition monitoring and fault diagnosis methods used in electric drive systems.", "author_names": [ "H Al-Sheikh", "Ouadie Bennouna", "Ghaleb Hoblos", "Nazih Moubayed" ], "corpus_id": 5728516, "doc_id": "5728516", "n_citations": 15, "n_key_citations": 1, "score": 0, "title": "Study on power converters used in hybrid vehicles with monitoring and diagnostics techniques", "venue": "MELECON 2014 2014 17th IEEE Mediterranean Electrotechnical Conference", "year": 2014 }, { "abstract": "Defense applications require quality electrical power in the form of three phase/single phase AC, 50 Hz/400 Hz and regulated DC power in general in the form of 5/12/24/28/48 V. To full fill these requirements, power conversion systems in the form of UPS, PCS, SMPS are required to be developed. Also various applications require different servo drives for controlled and desired speed torque applications. Hence it is important to have efficient, compact, and reliable power conversion units with high power density to supply a wide range of loads for Military systems. More and more efforts are required for better power electronic systems in terms of reliability to ensure high availability, long life, sufficient robustness, low maintenance for such applications. Wideband gap devices such as Silicon Carbide (SiC) and Gallium Nitride (GaN) devices in power electronic converters can be used to reduce the device losses in futuristic defense applications. This paper presents the over view, need and requirement, customization and design aspects of power converter systems for defense applications. Some of the case studies on recent developments of such variants of power conditioning systems are also presented in this paper.", "author_names": [ "Kirti Rathod", "Arbind Kumar", "Geeta Waghulde", "Pradeep Kurulkar" ], "corpus_id": 3888063, "doc_id": "3888063", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Power supply systems for defence applications a review part: II power conditioner system", "venue": "2017 National Power Electronics Conference (NPEC)", "year": 2017 }, { "abstract": "Condition monitoring is needed in power electronic systems as a cost effective means of improving reliability. Packaging related solder fatigue has been identified as one of the main root causes of power electronic module failures. This paper presents a method to monitor solder fatigue inside a module by identifying the increase of internal thermal resistance due to that solder fatigue, taking account of the masking effect of the variable operating point. It is assumed that the total loss in the module increases as junction temperature rises, causing an increase in case above ambient temperature rise, which can be measured. A dynamic thermal model of the heat sink is utilized to estimate the power loss from temperature measurements, while a device power loss model is developed to estimate the internal thermal resistance by considering the converter electrical loading. Experiment and simulation are used to demonstrate the concept and verify the method.", "author_names": [ "Dawei Xiang", "Li Ran", "Peter J Tavner", "Angus T Bryant", "Shaoyong Yang", "Phil Mawby" ], "corpus_id": 13878797, "doc_id": "13878797", "n_citations": 122, "n_key_citations": 6, "score": 0, "title": "Monitoring Solder Fatigue in a Power Module Using Case Above Ambient Temperature Rise", "venue": "IEEE Transactions on Industry Applications", "year": 2011 }, { "abstract": "Reliability of power electronic systems is a major concern for application engineers in the automotive and power system sectors. Power electronic modules are one of the main sources of failure in wind energy conversion systems. Power electronic converters used in wind turbine electric drivetrains, railway traction, more electric aircrafts, marine propulsion and grid connected systems like FACTS/HVDC require reliable power devices and modules. Wide bandgap semiconductors like SiC have demonstrated enlarged electrothermal Safe Operating Areas compared with silicon devices. However, the reliability of SiC power modules and packages has been identified as an area of potential weakness. Traditional packaging systems have been developed for Si hence the different thermomechanical properties of SiC cause different stresses in the packaging thereby potentially causing reduced reliability. This paper identifies some of the key areas for the development of reliable power electronic systems using SiC. The focus is on condition monitoring, packaging system innovation and thermo mechanical stress analysis as a function of the mechanical properties of Si and SiC. Power cycling experiments and finite element models have been used to support the analysis.", "author_names": [ "J Ortiz Gonzalez", "Li Ran", "A M Soli", "Zarina Davletzhanova", "Olayiwola Alatise", "Philip A Mawby", "Borong Hu", "Zheng Zeng", "Hai Ren", "Li Hui", "Shengyou Xu" ], "corpus_id": 5507330, "doc_id": "5507330", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Enabling high reliability power modules: A multidisciplinary task", "venue": "2016 International Symposium on 3D Power Electronics Integration and Manufacturing (3D PEIM)", "year": 2016 }, { "abstract": "Condition monitoring is desired by power electronic system designers as a cost effective means of improving reliability. This paper presents a method to monitor solder fatigue inside a power module by identifying internal thermal resistance increases due to solder fatigue, taking account of the masking effects of a variable operating condition. It is assumed that the total power loss increases as junction temperature rises, causing an increase in the case temperature above ambient, which can be measured. A dynamic thermal model of the heat sink is established, to estimate power loss by measurement, while a device power loss model is developed to estimate internal thermal resistance by further considering the converter electrical loading. Experiment and simulation using validated models are used to characterise the proposed method and verify the concept.", "author_names": [ "Dawei Xiang", "Li Ran", "Peter J Tavner", "Shaoyong Yang", "Angus T Bryant", "Philip A Mawby" ], "corpus_id": 42005265, "doc_id": "42005265", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Monitoring solder fatigue in a power module using the rise of case above ambient temperature", "venue": "2010 IEEE Energy Conversion Congress and Exposition", "year": 2010 } ]

[ { "abstract": "CONJUGATED polymers are organic semiconductors, the semiconducting behaviour being associated with the p molecular orbitals delocalized along the polymer chain. Their main advantage over non polymeric organic semiconductors is the possibility of processing the polymer to form useful and robust structures. The response of the system to electronic excitation is nonlinear the injection of an electron and a hole on the conjugated chain can lead to a self localized excited state which can then decay radiatively, suggesting the possibility of using these materials in electroluminescent devices. We demonstrate here that poly(p phenylene vinylene) prepared by way of a solution processable precursor, can be used as the active element in a large area light emitting diode. The combination of good structural properties of this polymer, its ease of fabrication, and light emission in the green yellow part of the spectrum with reasonably high efficiency, suggest that the polymer can be used for the development of large area light emitting displays.", "author_names": [ "Jeremy H Burroughes", "Donal D C Bradley", "A Robinson Brown", "R N Marks", "K Mackay", "Richard H Friend", "P L Burns", "Andrew B Holmes" ], "corpus_id": 43158308, "doc_id": "43158308", "n_citations": 7621, "n_key_citations": 18, "score": 1, "title": "Light emitting diodes based on conjugated polymers", "venue": "Nature", "year": 1990 }, { "abstract": "Nature 347, 539 541 (1990) IN the published version of this paper the name of one of the authors was incorrectly cited as P. L. Burns rather than P. L. Burn. His address is the University Chemical Laboratory, Cambridge, rather than the University Chemistry Laboratory as stated. GUIDE TO AUTHORS Please follow these guidelines so thatyoui be handled expeditiously.", "author_names": [ "Jeremy H Burroughes", "Donal D C Bradley", "A Robinson Brown", "R N Marks", "K Mackay", "Richard H Friend", "Paul L Burn", "Andrew B Holmes" ], "corpus_id": 4370680, "doc_id": "4370680", "n_citations": 1965, "n_key_citations": 12, "score": 0, "title": "Light emitting diodes based on conjugated polymers", "venue": "Nature", "year": 1990 }, { "abstract": "Wide range low voltage continuous color tuning is achieved in multilayer light emitting diodes based exclusively on the commonly used high efficiency electroluminescent conjugated polymers. There are three layers for red, green, and blue emission, and one extra layer for electron blocking. The color of the emitted photon depends on the position of the electron hole recombination. Due to the stronger field dependence of the electron mobility relative to the hole mobility, the recombination zone is pushed away from the cathode and concentrated in different emissive layers as the voltage increases.", "author_names": [ "C C Huang", "Hsin-Fei Meng", "G K Ho", "Chiou-Feng Chen", "Chian-Shu Hsu", "Jian-Ming Huang", "Sheng-Fu Horng", "Boyu Chen", "L C Chen" ], "corpus_id": 122695013, "doc_id": "122695013", "n_citations": 57, "n_key_citations": 0, "score": 0, "title": "Color tunable multilayer light emitting diodes based on conjugated polymers", "venue": "", "year": 2004 }, { "abstract": "A series of random conjugated copolymers PFCFS1 20 with 2,5 diphenyl 3,4 bis(3 fluorophenyl) silole (fluorinated TPS) chemically doped in 2,7 fluorene 2,7 carbazole main chain were successfully synthesized and characterized. Polymers PFCFS1 20 with fluorinated TPS contents from 1 to 20 possess high weight average molecular weights between 63.5 and 114.1 kg mol 1. The absorption spectra of THF solutions and films of PFCFS1 20 are very similar, showing peaks around 385 nm and optical band gaps around 2.87 eV. Almost no red shifts of the absorption peaks from a solution to a solid state film for the four copolymers indicate that their interchain interactions are extremely weak. PFCFS1 20 solutions show blue emissions with very limited intrachain excitation energy transfers. The films of PFCFS1 20 also display blue emissions with main peaks at 449 nm for PFCFS1 and 475 nm for PFCFS20, suggesting that the fluorinated TPS may comprise more twisted phenyl peripherals. Two types of electroluminescence (EL) devices with configurations of ITO/PEDOT:PSS/PFCFS/CsF/Al and ITO/PEDOT:PSS/PFCFS/TPBI/CsF/Al were investigated. It was found that PFCFS1 20 in the two types of EL devices could show blue to sky blue emissions. Among PFCFS1 20, for EL devices without TPBI layer, PFCFS5 possesses the best device performances with maximum luminous efficiency (LEmax) of 1.46 cd A 1 and maximum external quantum efficiency (EQEmax) of 0.93 The insertion of TPBI as the electron transport layer remarkably improves the EL performances. Also PFCFS5 displays the best LEmax of 4.59 cd A 1 and EQEmax of 3.21 The latter one is among the best efficiency so far reported for silole containing polymers. Our results suggest that the fluorinated TPS is an efficient chromophore for constructions of blue emissive conjugated polymers.", "author_names": [ "Lianjie Zhang", "Zhulin Liu", "Xiaofei Zhang", "Junwu Chen", "Yong Cao" ], "corpus_id": 94409120, "doc_id": "94409120", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Efficient Blue Light Emitting Diodes Based on Conjugated Polymers with Fluorinated Silole Chemically Doped in Fluorene Carbazole Main Chain", "venue": "Journal of Inorganic and Organometallic Polymers and Materials", "year": 2014 }, { "abstract": "", "author_names": [ "Paul L Burn", "Andrew B Holmes", "Arno Kraft", "A Robinson Brown", "Donal D C Bradley", "Richard H Friend" ], "corpus_id": 94487490, "doc_id": "94487490", "n_citations": 60, "n_key_citations": 0, "score": 0, "title": "Light Emitting Diodes Based on Conjugated Polymers: Control of Colour and Efficiency", "venue": "", "year": 1992 }, { "abstract": "", "author_names": [ "Changyun Jiang", "Wei Yang", "Junbiao Peng", "Steven Shuyong Xiao", "Yong Cao" ], "corpus_id": 97562167, "doc_id": "97562167", "n_citations": 193, "n_key_citations": 0, "score": 0, "title": "High Efficiency, Saturated Red Phosphorescent Polymer Light Emitting Diodes Based on Conjugated and Non Conjugated Polymers Doped with an Ir Complex", "venue": "", "year": 2004 }, { "abstract": "Abstract A series of blue light emitting conjugated polymers based on electron donating trifluoren 2 ylamine and electron deficient dibenzothiophene S,S dioxide were synthesized via typical Suzuki coupling reactions. Their thermal, photophysical and electrochemical properties were fully studied. Owing to the excellent thermal stability, film forming ability as well as the favorable energy levels of the polymers, highly efficient non doped single layer blue devices by using these polymers as an emitting layer (EML) were achieved. Among them, the device based on PSFOFN1 showed the highest maximum current efficiency (CEmax) of 1.99 cd/A. Moreover, the device presented small efficiency roll off with current efficiency (CE) of 1.97 cd/A at high brightness up to 100 cd/m2. In addition, the Commission Internationale de L'Eclairage (CIE) coordinates of all the devices are very close to the deep blue region. Our findings suggest the potential applications of the polymers in full color flat panel displays and organic lighting.", "author_names": [ "Hua Ye", "Baofeng Zhao", "Dongyun Li", "Dongcheng Chen", "Gaozhan Xie", "Shi-Jian Su", "Wei Yang", "Yong Cao" ], "corpus_id": 92861145, "doc_id": "92861145", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Highly efficient non doped single layer blue organic light emitting diodes based on light emitting conjugated polymers containing trifluoren 2 ylamine and dibenzothiophene S,S dioxide", "venue": "", "year": 2015 }, { "abstract": "Since the first attempt that was made to obtain direct circularly polarized (CP) light from OLEDs by Meijer et al. in 1997, considerable efforts have been devoted to the development of circularly polarized organic light emitting diodes (CP OLEDs) particularly in the recent years. Circularly polarized electroluminescence (CPEL) based on OLEDs has attracted increasing interest for its efficient ability to generate CP light directly and wide potential applications in 3D displays, optical data storage, and optical spintronics. In this review, we systematically summarize the recent progress in chiral emitter based OLEDs with CPEL properties including CPEL based on chiral conjugated polymers, CPEL based on chiral metal complexes, and CPEL based on chiral simple organic molecules, especially chiral thermally activated delayed fluorescence (TADF) molecules. We believe that this review will provide a promising perspective of chiral emitter based OLEDs with CPEL properties for a broad range of scientists in different disciplinary areas and attract a growing number of researchers to this fast growing research field.", "author_names": [ "Da-Wei Zhang", "Meng Li", "Chuan-Feng Chen" ], "corpus_id": 210946673, "doc_id": "210946673", "n_citations": 81, "n_key_citations": 0, "score": 0, "title": "Recent advances in circularly polarized electroluminescence based on organic light emitting diodes.", "venue": "Chemical Society reviews", "year": 2020 }, { "abstract": "White light emitting diodes (LEDs) were fabricated using GaN based 380 nm UV LEDs precoated with the composite of blue emitting polymer (poly[(9,9 dihexylfluorenyl 2,7 diyl) alt co (2 methoxy 5 {2 ethylhexyloxy) 1 ,4 phenylene) yellow green emitting polymer (poly[(9,9 dioctylfluorenyl 2,7 diyl) co (1,4 benzo {2,1',3} thiadiazole) and 605 nm red emitting quantum dots (QDs) CdSe cores were obtained by solvothermal route using CdO, Se precursors and ZnS shells were synthesized by using diethylzinc, and hexamethyldisilathiane precursors. The optical properties of CdSe/ZnS QDs were characterized by UV visible and photoluminescence (PL) spectra. The structural data and composition of the QDs were transmission electron microscopy (TEM) and EDX technique. The quantum yield and size of the QDs were 58.7% and about 6.7 nm, respectively. Three band white light was generated by hybridizing blue (430 nm) green (535 nm) and red (605 nm) emission. The color rendering index (CRI) of the device was extremely improved by introducing the QDs. The CIE 1931 chromaticity coordinate, color temperature, and CRI of a white LED at 20 mA were (0.379, 0.368) 3969 K, and 90, respectively.", "author_names": [ "Hyunchul Jung", "Wonkeun Chung", "Chang Hun Lee", "Sung Hyun Kim" ], "corpus_id": 21410340, "doc_id": "21410340", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Fabrication of white light emitting diodes based on UV light emitting diodes with conjugated polymers (CdSe/ZnS) quantum dots as hybrid phosphors.", "venue": "Journal of nanoscience and nanotechnology", "year": 2012 }, { "abstract": "Abstract We report the use of green and blue fluorene conjugated polymers doped with hole transport materials consisting of triarylamine copolymers to fabricate bright and efficient blue and green single layer light emitting diodes (LEDs) These blends show enhanced quantum and power efficiency, much higher brightness and current densities and lower turn on and operating voltages compared with undoped devices. Optimised blue emission devices exhibited a maximum brightness of 1550 cd/m 2 a maximum external electroluminescence quantum efficiency of 0.9 cd/A or 0.4% and a maximum power efficiency of 0.3 lm/W. Optimised green emission devices showed a maximum brightness of 7400 cd/m 2 a maximum external electroluminescence quantum yield of 0.9% or 2.75 cd/A and a maximum power efficiency of 0.64 lm/W at high brightness.", "author_names": [ "Leonidas C Palilis", "David G Lidzey", "Michael Redecker", "Donal D C Bradley", "Michael Inbasekaran", "Edmund P Woo", "Weishi Wu" ], "corpus_id": 95307487, "doc_id": "95307487", "n_citations": 25, "n_key_citations": 0, "score": 0, "title": "Bright and efficient blue and green light emitting diodes based on conjugated polymer blends", "venue": "", "year": 2000 } ]

[ { "abstract": "The RC based power rail ESD clamp circuit with the n channel metal oxide semiconductor (NMOS) transistor drawn in the layout style of big field effect transistor (BigFET) has been utilized to effectively enhance the ESD robustness of CMOS ICs. In this work, a new ESD transient detection circuit without using the capacitor has been proposed and verified in a 65 nm 1.2 V CMOS process. The layout area of the new ESD transient detection circuit can be greatly reduced by more than 54% as compared to the traditional RC based ESD transient detection circuit realized with capacitor. From the experimental results, the new proposed ESD transient detection circuit with adjustable holding voltage can achieve long enough turn on duration under the ESD stress condition, as well as better immunity against mistrigger and transient induced latch on event under the fast power on and transient noise conditions.", "author_names": [ "Chih-Ting Yeh", "Ming-Dou Ker" ], "corpus_id": 18653638, "doc_id": "18653638", "n_citations": 35, "n_key_citations": 6, "score": 1, "title": "Capacitor Less Design of Power Rail ESD Clamp Circuit With Adjustable Holding Voltage for On Chip ESD Protection", "venue": "IEEE Journal of Solid State Circuits", "year": 2010 }, { "abstract": "This paper discusses concurrent design and analysis of the first 8.5 kV electrostatic discharge (ESD) protected single pole ten throw (SP10T) transmit/receive (T/R) switch for quad band (0.85/0.9/1.8/1.9 GHz) GSM and multiple band WCDMA smartphones. Implemented in a 0.18 mm SOI CMOS, this SP10T employs a series shunt topology for the time division duplex (TDD) transmitting (Tx) and receiving (Rx) and frequency division duplex (FDD) transmitting/receiving (TRx) branches to handle the high GSM transmitter power. The measured P0.1 dB, insertion loss and Tx Rx isolation in the lower/upper bands are 36.4/34.2 dBm, 0.48/0.81 dB and 43/40 dB, respectively, comparable to commercial products with no/little ESD protection in high cost SOS and GaAs technologies. Feed forward capacitor (FFC) and AC floating bias techniques are used to further improve the linearity. An ESD switch co design technique is developed that enables simultaneous whole chip design optimization for both ESD protection and SP10T circuits.", "author_names": [ "X Shawn Wang", "Xiao-fan Wang", "Fei Lu", "Chen Zhang", "Zongyu Dong", "Lisha Wang", "Rui Ma", "Zitao Shi", "Albert Z Wang", "M Frank Chang", "Dawn Wang", "Alvin J Joseph", "C Patrick Yue" ], "corpus_id": 30871699, "doc_id": "30871699", "n_citations": 44, "n_key_citations": 3, "score": 0, "title": "Concurrent Design Analysis of High Linearity SP10T Switch With 8.5 kV ESD Protection", "venue": "IEEE Journal of Solid State Circuits", "year": 2014 }, { "abstract": "This paper presents two 60 GHz low noise amplifiers (LNAs) with different electrostatic (ESD) protection schemes, including the diode based and LC based configurations. By codesigning ESD network and input matching, both LNAs are optimized for minimum noise figure (NF) while maintaining a similar gain. Compared with the conventional double diode approach, the proposed LC based design uses a high current capability spiral inductor and a high breakdown voltage metal oxide metal capacitor as effective bidirectional ESD protection, showing much improved ESD protection level and NF under reduced power consumption. The test results demonstrate an over 8 kV human body model ESD level and an over 13 A very fast transmission line pulse current level for charge device model ESD protection. The measured NF and power gain are 5.3 dB and 17.5 dB, respectively, at 58 GHz, under a power consumption of only 18 mW. To the best of our knowledge, the LC based ESD protected LNA demonstrates a highest ESD protection level with a lowest NF, compared with prior arts operating at similar frequencies.", "author_names": [ "Ming-Hsien Tsai", "Shawn S H Hsu", "Fu-Lung Hsueh", "Chewnpu Jou", "Tzu-Jin Yeh" ], "corpus_id": 16430900, "doc_id": "16430900", "n_citations": 20, "n_key_citations": 1, "score": 0, "title": "Design of 60 GHz Low Noise Amplifiers With Low NF and Robust ESD Protection in 65 nm CMOS", "venue": "IEEE Transactions on Microwave Theory and Techniques", "year": 2013 }, { "abstract": "ESD protection structure for vertical NPN transistor in a 5 V 0.6 mm BiCMOS process was designed.A modified self triggered ESD protection structure with P+/N well diode was proposed to solve the problem of high triggering voltage in traditional self triggered ESD structure for vertical NPN device.Parasitic collector base capacitance and PN junction capacitance were used as capacitor coupler.Test results indicated that triggering voltage of the protection structure could be effectively reduced,and its protection level exceeded 4 kV human body model.", "author_names": [ "Gu Xiaofeng" ], "corpus_id": 112036495, "doc_id": "112036495", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design and Analysis of ESD Protection Structure for Vertical NPN Transistors", "venue": "", "year": 2012 }, { "abstract": "By the electrostatic discharge (ESD)/matching co design methodology, a wideband low noise amplifier (LNA) using a grounded spiral inductor in conjunction with a MOM capacitor for ESD protection and wideband matching is demonstrated in a 65 nm CMOS. The shunt inductor provides an effective bidirectional ESD protection to the ground and the series capacitor greatly enhances the breakdown level in the current discharge path. The measurement results demonstrate an over 8 kV human body model ESD protection level with almost no RF characteristic degradation after ESD zapping. Under a power consumption of 5.6 mW, the ESD protected LNA presents a flat NF and power gain of 3.3 3.9 dB and 16.6 17.9 dB, respectively, in the frequency range of 18.5 24.5 GHz, and a 3 dB bandwidth of 17.5 26 GHz is achieved.", "author_names": [ "Ming-Hsien Tsai", "Shawn S H Hsu", "Fu-Lung Hsueh", "Chewnpu Jou", "Tzu-Jin Yeh" ], "corpus_id": 30098410, "doc_id": "30098410", "n_citations": 26, "n_key_citations": 1, "score": 0, "title": "A 17.5 26 GHz Low Noise Amplifier With Over 8 kV ESD Protection in 65 nm CMOS", "venue": "IEEE Microwave and Wireless Components Letters", "year": 2012 }, { "abstract": "This paper presents an ESD protected V band (f0 at 58 GHz) low noise amplifier (LNA) in 65 nm CMOS. Instead of using the conventional diode based RF ESD design, a high current capability spiral inductor and a high breakdown MOM capacitor are employed as effective bi directional ESD protection network, and also as part of the input matching by the co design approach. The measured results demonstrate an over 8 kV HBM ESD protection level with a NF of 5.3 dB and a power gain of 17.5 dB at 58 GHz, under a power consumption of 18 mW. To our best knowledge, this LNA presents a highest ESD protection level and a lowest NF, compared with prior arts in a similar frequency range.", "author_names": [ "Ming-Hsien Tsai", "Shawn S H Hsu", "Tzu-Jin Yeh", "Chewnpu Jou", "Fu-Lung Hsueh" ], "corpus_id": 12787151, "doc_id": "12787151", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "A V band low noise amplifier with 5.3 dB NF and over 8 kV ESD protection in 65 nm RF CMOS", "venue": "2012 IEEE/MTT S International Microwave Symposium Digest", "year": 2012 }, { "abstract": "Capacitor couple technique used to lower snapback trigger voltage and to ensure uniform ESD current distribution in deep submicron CMOS on chip ESD protection circuit is proposed. The coupling capacitor is realized by a poly layer right under the wire bonding metal pad without increasing extra layout area to the pad. A timing original design model has been derived to calculate the capacitor couple efficiency of this proposed ESD protection circuit. Using this capacitor couple ESD protection circuit, the thinner gate oxide of CMOS devices in deep submicron low voltage CMOS ASIC can be effectively protected.", "author_names": [ "Ming-Dou Ker", "Chung-Yu Wu", "Tao Cheng", "Hun-Hsien Chang" ], "corpus_id": 29790686, "doc_id": "29790686", "n_citations": 62, "n_key_citations": 1, "score": 0, "title": "Capacitor couple ESD protection circuit for deep submicron low voltage CMOS ASIC", "venue": "IEEE Trans. Very Large Scale Integr. Syst.", "year": 1996 }, { "abstract": "A novel NMOS Electrostatic Discharge (ESD) clamp circuit is proposed for a 0.35 mm Bipolar CMOS DMOS (BCD) process. The proposed ESD clamp has a non snapback characteristic because of gate coupled effect. This proposed ESD clamp circuit is developed without additional components made possible by replacing a capacitor with an isolated parasitic capacitor. The result of the proposed ESD clamp circuit is measured by 100 ns Transmission Line Pulse (TLP) system. From the measurement, it was observed that the proposed ESD clamp has approximately 40% lower triggering voltage compared to the conventional gate grounded NMOS ESD clamp. This is achieved without degradation of the other ESD design key parameter. The proposed ESD clamp also has high robustness characteristics compared to the conventional RC triggered NMOS ESD clamp circuit.", "author_names": [ "Jae-Young Park", "Dae-Woo Kim", "Young-Sang Son", "Jong-Kyu Song", "Chang-Soo Jang", "Won-Young Jung" ], "corpus_id": 1259426, "doc_id": "1259426", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Non snapback ESD Protection Clamp Circuit Using Isolated Parasitic Capacitance in a 0.35 um Bipolar CMOS DMOS Process", "venue": "IEICE Trans. Electron.", "year": 2011 }, { "abstract": "A design model is proposed to exactly simulate operating principles of gate coupling NMOS (GCNMOS) ESD protection circuit under ESD stress. Using this model, adequate coupling capacitor C/sub n/ and coupling resistor R/sub n/ can be calculated to improve the efficiency of GCNMOS ESD protection circuit.", "author_names": [ "Wang Yuan", "Jia Song", "Chen Zhongjian", "Zhang Gang-gang", "Ji Lijiu" ], "corpus_id": 26518396, "doc_id": "26518396", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "A design model of gate coupling NMOS ESD protection circuit", "venue": "Proceedings. 7th International Conference on Solid State and Integrated Circuits Technology, 2004.", "year": 2004 }, { "abstract": "The RF junction varactors are employed as electro static discharge (ESD) protection devices and co designed with 60 GHz low noise amplifier (LNA) fabricated in a 65 nm CMOS technology. The junction varactor acts as an ESD diode to bypass ESD current during ESD zapping, and also utilized as a capacitor to be a part of input matching network of the LNA in normal RF operation. By transmission line pulse (TLP) measurement, the ESD protection capabilities of RF junction varactors are characterized with different device parameters. The experimental results demonstrate excellent second breakdown currents (It2) and high ratios of the ESD levels to parasitic capacitances (VESD/CESD) With ESD/matching co design methodology, the ESD protected LNA demonstrates a second breakdown current It2 of 1.4 A, corresponding to a 2 kV human body model (HBM) ESD protection level with a noise figure (NF) of 6.6 dB and a peak gain of 16.5 dB at 60 GHz under a power consumption of only 28 mW.", "author_names": [ "Ming-Hsien Tsai", "Sing-Kai Huang", "Shawn S H Hsu" ], "corpus_id": 28124563, "doc_id": "28124563", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Electro Static Discharge Protection Design for V Band Low Noise Amplifier Using Radio Frequency Junction Varactor (Special Issue Solid State Devices and Materials)", "venue": "", "year": 2013 } ]

[ { "abstract": "Summary Recently, non fullerene n type organic semiconductors have attracted significant attention as acceptors in organic photovoltaics (OPVs) due to their great potential to realize high power conversion efficiencies. The rational design of the central fused ring unit of these acceptor molecules is crucial to maximize device performance. Here, we report a new class of non fullerene acceptor, Y6, that employs a ladder type electron deficient core based central fused ring (dithienothiophen[3.2 b] pyrrolobenzothiadiazole) with a benzothiadiazole (BT) core to fine tune its absorption and electron affinity. OPVs made from Y6 in conventional and inverted architectures each exhibited a high efficiency of 15.7% measured in two separate labs. Inverted device structures were certified at Enli Tech Laboratory demonstrated an efficiency of 14.9% We further observed that the Y6 based devices maintain a high efficiency of 13.6% with an active layer thickness of 300 nm. The electron deficient core based fused ring reported in this work opens a new door in the molecular design of high performance acceptors for OPVs.", "author_names": [ "Jun Yuan", "Yunqiang Zhang", "Liuyang Zhou", "Guichuan Zhang", "Hin-Lap Yip", "Tsz-Ki Lau", "Xinhui Lu", "Can Zhu", "Hongjian Peng", "Paul A Johnson", "Mario Leclerc", "Yong Cao", "Jacek Ulanski", "Yongfang Li", "Yingping Zou" ], "corpus_id": 139354200, "doc_id": "139354200", "n_citations": 1788, "n_key_citations": 1, "score": 1, "title": "Single Junction Organic Solar Cell with over 15% Efficiency Using Fused Ring Acceptor with Electron Deficient Core", "venue": "Joule", "year": 2019 }, { "abstract": "phenylenevinylene)s L4. Fluorene Based Conjugated Polymers L4.1. Fluorene Based Copolymers ContainingElectron Rich MoietiesM4.2. Fluorene Based Copolymers ContainingElectron Deficient MoietiesN4.3. Fluorene Based Copolymers ContainingPhosphorescent ComplexesQ5. Carbazole Based Conjugated Polymers R5.1. Poly(2,7 carbazole) Based Polymers R5.2. Indolo[3,2", "author_names": [ "Yen-Ju Cheng", "Sheng-Hsiung Yang", "Chain-Shu Hsu" ], "corpus_id": 30888023, "doc_id": "30888023", "n_citations": 3276, "n_key_citations": 18, "score": 0, "title": "Synthesis of conjugated polymers for organic solar cell applications.", "venue": "Chemical reviews", "year": 2009 }, { "abstract": "Besides broadening of the absorption spectrum, modulating molecular energy levels, and other well studied properties, a stronger intramolecular electron push pull effect also affords other advantages in nonfullerene acceptors. A strong push pull effect improves the dipole moment of the wings in IT 4F over IT M and results in a lower miscibility than IT M when blended with PBDB TF. This feature leads to higher domain purity in the PBDB TF:IT 4F blend and makes a contribution to the better photovoltaic performance. Moreover, the strong push pull effect also decreases the vibrational relaxation, which makes IT 4F more promising than IT M in reducing the energetic loss of organic solar cells. Above all, a power conversion efficiency of 13.7% is recorded in PBDB TF:IT 4F based devices.", "author_names": [ "Wanning Li", "Long Ye", "Sunsun Li", "Huifeng Yao", "Harald W Ade", "Jianhui Hou" ], "corpus_id": 3847310, "doc_id": "3847310", "n_citations": 260, "n_key_citations": 1, "score": 0, "title": "A High Efficiency Organic Solar Cell Enabled by the Strong Intramolecular Electron Push Pull Effect of the Nonfullerene Acceptor.", "venue": "Advanced materials", "year": 2018 }, { "abstract": "Fast and efficient charge separation is essential to achieve high power conversion efficiency in organic solar cells (OSCs) In state of the art OSCs, this is usually achieved by a significant driv", "author_names": [ "Jiajun Liu", "Shangshang Chen", "Deping Qian", "Bhoj Gautam", "Guofang Yang", "Jingbo Zhao", "Jonas Bergqvist", "Fengling Zhang", "Wei Ma", "Harald W Ade", "Olle Inganas", "Kenan Gundogdu", "Feng Gao", "He Yan" ], "corpus_id": 99838388, "doc_id": "99838388", "n_citations": 770, "n_key_citations": 3, "score": 0, "title": "Fast charge separation in a non fullerene organic solar cell with a small driving force", "venue": "", "year": 2016 }, { "abstract": "Fabricating organic solar cells (OSCs) with a tandem structure has been considered an effective method to overcome the limited light absorption spectra of organic photovoltaic materials. Currently, the most efficient tandem OSCs are fabricated by adopting fullerene derivatives as acceptors. In this work, we designed a new non fullerene acceptor with an optical band gap (Egopt) of 1.68 eV for the front subcells and optimized the phase separation morphology of a fullerene free active layer with an Egopt of 1.36 eV to fabricate the rear subcell. The two subcells show a low energy loss and high external quantum efficiency, and their photoresponse spectra are complementary. In addition, an interconnection layer (ICL) composed of ZnO and a pH neutral self doped conductive polymer, PCP Na, with high light transmittance in the near IR range was developed. From the highly optimized subcells and ICL, solution processed fullerene free tandem OSCs with an average power conversion efficiency (PCE) greater than 13% were obtained.", "author_names": [ "Yong Cui", "Huifeng Yao", "Bowei Gao", "Yunpeng Qin", "Shaoqing Zhang", "Bei Yang", "Chang He", "Bowei Xu", "Jianhui Hou" ], "corpus_id": 326352, "doc_id": "326352", "n_citations": 350, "n_key_citations": 3, "score": 0, "title": "Fine Tuned Photoactive and Interconnection Layers for Achieving over 13% Efficiency in a Fullerene Free Tandem Organic Solar Cell.", "venue": "Journal of the American Chemical Society", "year": 2017 }, { "abstract": "Bulk heterojunction organic solar cells (OSCs) have received considerable attention with significant progress recently and offer a promising outlook for portable energy resources and building integrated photovoltaics in the future. Now, it is urgent to promote the research of OSCs toward their commercialization. For the commercial application of OSCs, it is of great importance to develop high performance, high stability, and low cost photovoltaic materials. In this review, a comprehensive overview of the fundamental requirements of photoactive layer materials and interface layer materials toward commercialization is provided, mainly focusing on high performance, green manufacturing, simplifying device fabrication processes, stability, and cost issues. Furthermore, the perspectives and opportunities for this emerging field of materials science and engineering are also discussed.", "author_names": [ "Rongming Xue", "Jingwen Zhang", "Yaowen Li", "Yongfang Li" ], "corpus_id": 51975017, "doc_id": "51975017", "n_citations": 121, "n_key_citations": 0, "score": 0, "title": "Organic Solar Cell Materials toward Commercialization.", "venue": "Small", "year": 2018 }, { "abstract": "Ternary organic solar cells (OSCs) have attracted much research attention in the past few years, as ternary organic blends can broaden the absorption range of OSCs without the use of complicated tandem cell structures. Despite their broadened absorption range, the light harvesting capability of ternary OSCs is still limited because most ternary OSCs use thin active layers of about 100 nm in thickness, which is not sufficient to absorb all photons in their spectral range and may also cause problems for future roll to roll mass production that requires thick active layers. In this paper, we report a highly efficient ternary OSC (11.40% obtained by incorporating a nematic liquid crystalline small molecule (named benzodithiophene terthiophene rhodanine (BTR) into a state of the art PTB7 Th:PC71BM binary system. The addition of BTR into PTB7 Th:PC71BM was found to improve the morphology of the blend film with decreased p p stacking distance, enlarged coherence length, and enhanced domain purity. This resulted in more efficient charge separation, faster charge transport, and less bimolecular recombination, which, when combined, led to better device performance even with thick active layers. Our results show that the introduction of highly crystalline small molecule donors into ternary OSCs is an effective means to enhance the charge transport and thus increase the active layer thickness of ternary OSCs to make them more suitable for roll to roll production than previous thinner devices.", "author_names": [ "Guichuan Zhang", "Kai Zhang", "Qingwu Yin", "Xiao-Fang Jiang", "Zaiyu Wang", "Jingming Xin", "Wei Ma", "He Yan", "Fei Huang", "Yong Cao" ], "corpus_id": 207173219, "doc_id": "207173219", "n_citations": 305, "n_key_citations": 1, "score": 0, "title": "High Performance Ternary Organic Solar Cell Enabled by a Thick Active Layer Containing a Liquid Crystalline Small Molecule Donor.", "venue": "Journal of the American Chemical Society", "year": 2017 }, { "abstract": "Fullerene free organic solar cells show over 11% power conversion efficiency, processed by low toxic solvents. The applied donor and acceptor in the bulk heterojunction exhibit almost the same highest occupied molecular orbital level, yet exhibit very efficient charge creation.", "author_names": [ "Zhong Zheng", "Omar M Awartani", "Bhoj Gautam", "Delong Liu", "Yunpeng Qin", "Wanning Li", "A Bataller", "Kenan Gundogdu", "Harald W Ade", "Jianhui Hou" ], "corpus_id": 31804136, "doc_id": "31804136", "n_citations": 257, "n_key_citations": 0, "score": 0, "title": "Efficient Charge Transfer and Fine Tuned Energy Level Alignment in a THF Processed Fullerene Free Organic Solar Cell with 11.3% Efficiency.", "venue": "Advanced materials", "year": 2017 }, { "abstract": "A comparison of the efficiency, stability, and photophysics of organic solar cells employing poly[(5,6 difluoro 2,1,3 benzothiadiazol 4,7 diyl) alt (3,3' di(2 octyldodecyl) 2,2';5',2';5',2' quaterthiophen 5,5' diyl) (PffBT4T 2OD) as a donor polymer blended with either the nonfullerene acceptor EH IDTBR or the fullerene derivative, [6,6] phenyl C71 butyric acid methyl ester (PC71 BM) as electron acceptors is reported. Inverted PffBT4T 2OD:EH IDTBR blend solar cell fabricated without any processing additive achieves power conversion efficiencies (PCEs) of 9.5 0.2% The devices exhibit a high open circuit voltage of 1.08 0.01 V, attributed to the high lowest unoccupied molecular orbital (LUMO) level of EH IDTBR. Photoluminescence quenching and transient absorption data are employed to elucidate the ultrafast kinetics and efficiencies of charge separation in both blends, with PffBT4T 2OD exciton diffusion kinetics within polymer domains, and geminate recombination losses following exciton separation being identified as key factors determining the efficiency of photocurrent generation. Remarkably, while encapsulated PffBT4T 2OD:PC71 BM solar cells show significant efficiency loss under simulated solar irradiation \"burn in\" degradation) due to the trap assisted recombination through increased photoinduced trap states, PffBT4T 2OD:EH IDTBR solar cell shows negligible burn in efficiency loss. Furthermore, PffBT4T 2OD:EH IDTBR solar cells are found to be substantially more stable under 85 degC thermal stress than PffBT4T 2OD:PC71 BM devices.", "author_names": [ "Hyojung Cha", "Jiaying Wu", "Andrew Wadsworth", "Jade Nagitta", "Saurav Limbu", "Sebastian Pont", "Zhe Li", "Justin R Searle", "Mark F Wyatt", "Derya Baran", "Ji-seon Kim", "Iain McCulloch", "James R Durrant" ], "corpus_id": 205279854, "doc_id": "205279854", "n_citations": 117, "n_key_citations": 0, "score": 0, "title": "An Efficient, \"Burn in\" Free Organic Solar Cell Employing a Nonfullerene Electron Acceptor.", "venue": "Advanced materials", "year": 2017 }, { "abstract": "Abstract Carbazole based molecules are more important in organic solar cell (OSC) applications, because carbazole derivatives have more thermal stability, high hole transporting property, more electron rich (p type) material, higher photoconductivity, and better chemical stability. This review deals with bulk heterojunction organic solar cell (BHJ OSC) devices, structures, working principle, device characterization, perovskite type solar cell, and studies of the photovoltaic performance of carbazole based derivatives such as 2,7 carbazole, indolo[3,2 b ]carbazole containing donors (D) coupled with various acceptors (A) namely benzothiadiazole, thiazolothiazole, diketopyrrolopyrrole, and quinoxaline that are reported during the last decade and also dye sensitized solar cell (DSSC) performance of carbazole derivatives. We will briefly outline the relationship between the structure and power conversion efficiencies (PCEs)", "author_names": [ "Govindasamy Sathiyan", "E K T Sivakumar", "Ramasamy Ganesamoorthy", "Rangasamy Thangamuthu", "Pachagoundar Sakthivel" ], "corpus_id": 98194361, "doc_id": "98194361", "n_citations": 134, "n_key_citations": 0, "score": 0, "title": "Review of carbazole based conjugated molecules for highly efficient organic solar cell application", "venue": "", "year": 2016 } ]

[ { "abstract": "Low dimensional ferroelectrics are highly desired for applications and full of exotic physics. Here a functionalized MXene Hf2CF2 monolayer is theoretically studied, which manifests a nonpolar to polar transition upon moderate biaxial compressive strain. Accompanying this structural transition, a metal semiconductor transition occurs. The in plane shift of unilateral fluorine layer leads to a polarization pointing out of plane. Such ferroelectricity is unconventional, similar to the recentlyproposed interlayer sliding ferroelectricity but not identical. Due to its specific hexapetalous potential energy profile, the possible ferroelectric switching paths and domain walls are nontrivial, which are mediated via the metallic paraelectric state. In this sense, the metallic walls can be manipulated by reshaping the ferroelectric domains.", "author_names": [ "Ziwen Wang", "Ning Ding", "Churen Gui", "Ming An", "Shuai Dong" ], "corpus_id": 235795582, "doc_id": "235795582", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Ferroelectricity in strained Hf2CF2 monolayer", "venue": "Physical Review Materials", "year": 2021 }, { "abstract": "Van der Waals (vdW) materials have greatly expanded our design space of heterostructures by allowing individual layers to be stacked at non equilibrium configurations, for example via control of the twist angle. Such heterostructures not only combine characteristics of the individual building blocks, but can also exhibit emergent physical properties absent in the parent compounds through interlayer interactions. Here we report on a new family of emergent, nanometer thick, semiconductor 2D ferroelectrics, where the individual constituents are well studied non ferroelectric monolayer transition metal dichalcogenides (TMDs) namely WSe2, MoSe2, WS2, and MoS2. By stacking two identical monolayer TMDs in parallel, we obtain electrically switchable rhombohedral stacking configurations, with out of plane polarization that is flipped by in plane sliding motion. Fabricating nearly parallel stacked bilayers enables the visualization of moir\\'e ferroelectric domains as well as electric field induced domain wall motion with piezoelectric force microscopy (PFM) Furthermore, by using a nearby graphene electronic sensor in a ferroelectric field transistor geometry, we quantify the ferroelectric built in interlayer potential, in good agreement with first principles calculations. The novel semiconducting ferroelectric properties of these four new TMDs opens up the possibility of studying the interplay between ferroelectricity and their rich electric and optical properties.", "author_names": [ "Xirui Wang", "Kenji Yasuda", "James C Hone", "Pablo Jarillo-Herrero" ], "corpus_id": 237142429, "doc_id": "237142429", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Interfacial ferroelectricity in rhombohedral stacked bilayer transition metal dichalcogenides", "venue": "", "year": 2021 }, { "abstract": "According to the model of sliding ferroelectricity we proposed in 2017, a type of vertical polarization switchable via interlayer sliding may exist in a series of two dimensional van der Waals bilayers and multilayers. Such intriguing ferroelectricity has been recently experimentally confirmed in BN and WTe2 bilayer/multilayer systems. However, they are respectively insulators and metals with weak polarizations. Here, we search for a combination of high mobility semiconductors and ferroelectricity with relatively high polarizations, and we note that MoSi2N4 monolayer has been recently fabricated to centimeter scale based on MoN2 monolayer (Science 2020, 369, 670) We show first principles evidence of strong interlayer sliding ferroelectricity in high mobility semiconducting MoA2N4 (A Si or Ge) bilayers and multilayers. They possess tunable bandgaps within the desirable range for nanoelectronics, with the current highest polarizations in sliding ferroelectrics known to date due to strong interlayer van der Waals interactions. Such a successful combination of these properties may render the long sought and efficient computing in memory possible. Their high polarizations induce strong Moire potential and unique band alignments for exciton trapping in twisted MoA2N4 bilayer. The varying charge distribution of different stacking in MoN2/MoSi2N4 hetero bilayer also gives rise to a high alternating voltage when used as a nanogenerator, suggesting promising potential for energy harvesting.", "author_names": [ "Tingting Zhong", "Zhuhua Zhang", "Jinhua Gao", "Menghao Wu" ], "corpus_id": 236597197, "doc_id": "236597197", "n_citations": 1, "n_key_citations": 1, "score": 0, "title": "Sliding ferroelectricity in two dimensional MoA2N4 (A Si or Ge) bilayers: high polarizations and Moire potentials", "venue": "", "year": 2021 }, { "abstract": "Enriching the functionality of ferroelectric materials with visible light sensitivity and multiaxial switching capability would open up new opportunities for their applications in advanced information storage with diverse signal manipulation functions. We report experimental observations of robust intralayer ferroelectricity in two dimensional (2D) van der Waals layered a In2Se3 ultrathin flakes at room temperature. Distinct from other 2D and conventional ferroelectrics, In2Se3 exhibits intrinsically intercorrelated out of plane and in plane polarization, where the reversal of the out of plane polarization by a vertical electric field also induces the rotation of the in plane polarization. On the basis of the in plane switchable diode effect and the narrow bandgap ~1.3 eV) of ferroelectric In2Se3, a prototypical nonvolatile memory device, which can be manipulated both by electric field and visible light illumination, is demonstrated for advancing data storage technologies.", "author_names": [ "Chaojie Cui", "Weijin Hu", "Xingxu Yan", "Christopher Addiego", "Wenpei Gao", "Yaoling Wang", "Zhe Wang", "Linze Li", "Yingchun Cheng", "Peng Li", "Xixiang Zhang", "Husam N Alshareef", "Tom Wu", "Wenguang Zhu", "Xiaoqing Pan", "Lain-Jong Li" ], "corpus_id": 206745952, "doc_id": "206745952", "n_citations": 200, "n_key_citations": 2, "score": 0, "title": "Intercorrelated In Plane and Out of Plane Ferroelectricity in Ultrathin Two Dimensional Layered Semiconductor In2Se3.", "venue": "Nano letters", "year": 2018 }, { "abstract": "Ultrathin ferroelectric materials could potentially enable low power logic and nonvolatile memories 1 2 As ferroelectric materials are made thinner, however, the ferroelectricity is usually suppressed. Size effects in ferroelectrics have been thoroughly investigated in perovskite oxides the archetypal ferroelectric system 3 Perovskites, however, have so far proved unsuitable for thickness scaling and integration with modern semiconductor processes 4 Here we report ferroelectricity in ultrathin doped hafnium oxide (HfO 2 a fluorite structure oxide grown by atomic layer deposition on silicon. We demonstrate the persistence of inversion symmetry breaking and spontaneous, switchable polarization down to a thickness of one nanometre. Our results indicate not only the absence of a ferroelectric critical thickness but also enhanced polar distortions as film thickness is reduced, unlike in perovskite ferroelectrics. This approach to enhancing ferroelectricity in ultrathin layers could provide a route towards polarization driven memories and ferroelectric based advanced transistors. This work shifts the search for the fundamental limits of ferroelectricity to simpler transition metal oxide systems that is, from perovskite derived complex oxides to fluorite structure binary oxides in which 'reverse' size effects counterintuitively stabilize polar symmetry in the ultrathin regime. Enhanced switchable ferroelectric polarization is achieved in doped hafnium oxide films grown directly onto silicon using low temperature atomic layer deposition, even at thicknesses of just one nanometre.", "author_names": [ "Suraj S Cheema", "Dae Woong Kwon", "Nirmaan Shanker", "Roberto dos Reis", "Shang-Lin Hsu", "Jun Xiao", "Haigang Zhang", "Ryan Wagner", "Adhiraj Datar", "M McCarter", "Claudy Rayan Serrao", "Ajay K Yadav", "Golnaz Karbasian", "Cheng-Hsiang Hsu", "Ava J Tan", "Li-Chen Wang", "Vishal P Thakare", "Xiang Zhang", "Apurva Mehta", "Evguenia A Karapetrova", "Rajesh Vilas Chopdekar", "Padraic Shafer", "Elke Arenholz", "Chenming Calvin Hu", "Roger Proksch", "Ramamoorthy Ramesh", "Jim Ciston", "Sayeef S Salahuddin" ], "corpus_id": 216076611, "doc_id": "216076611", "n_citations": 110, "n_key_citations": 4, "score": 0, "title": "Enhanced ferroelectricity in ultrathin films grown directly on silicon", "venue": "Nature", "year": 2020 }, { "abstract": "The effect of annealing temperature on the ferroelectricity of HfAlOx with Al concentration of 4.5% is physically and electrically investigated by metal ferroelectric insulator semiconductor (MFIS) platform. HfAlOx with 600 degC annealing is confirmed to possess ferroelectricity by the formation of non centrosymmetry orthorhombic III phase, clockwise capacitance voltage hysteresis, significant polarization electric field hysteresis curve, and in depth analysis of current component as compared with non ferroelectric HfO2. Compared to commonly discussed MFM devices from which thermal annealing of 800 degC is required to induce ferroelectricity, the relatively lower thermal budget to form ferroelectric HfAlOx in MFIS devices can be attributed to the compressive thermal stress caused by the difference in thermal expansion between the Si substrate and HfAlOx during thermal annealing, and it is the stress that helps lower the annealing temperature to crystallize HfAlOx in the orthorhombic phase. In addition, MFIS devices with 600 degC annealed HfAlOx hold the prospect of becoming a promising candidate for memory applications by demonstrating a memory window of 0.6 V with 3 V operation voltage which is comparable with or superior to those with conventional ferroelectric films. Furthermore, the process to from ferroelectric HfAlOx based devices can be fully integrated into incumbent mass production fabs, empowering next generation memory technology.", "author_names": [ "Kuen-Yi Chen", "Ka-Lip Chu", "Pin-Hsuan Chen", "Yung-Hsien Wu" ], "corpus_id": 99481060, "doc_id": "99481060", "n_citations": 12, "n_key_citations": 1, "score": 0, "title": "Ferroelectricity of low thermal budget HfAlOx for devices with metal ferroelectric insulator semiconductor structure", "venue": "", "year": 2016 }, { "abstract": "Using a combination of Landau theoretical analysis and first principles calculations, we establish a spontaneous symmetry breaking of the metallic state of the 1T monolayer of MoS2 that opens up a band gap and leads to an unexpected yet robust ferroelectricity with ordering of electric dipoles perpendicular to its plane. Central to the properties of this thinnest known ferroelectric is a strong coupling of conducting states with valley phonons that induce an effective electric field. The current in a semiconducting 1T MoS2 channel can, thus, be controlled independently by changing its ferroelectric dipolar structure with a gate field, opening up a possibility of a class of nanoscale dipolectronic devices. Our analysis applies equally well to MoSe2, WS2, and WSe2, giving tunability in design of such devices based on two dimensional chalcogenides.", "author_names": [ "Sharmila N Shirodkar", "Umesh V Waghmare" ], "corpus_id": 34188597, "doc_id": "34188597", "n_citations": 200, "n_key_citations": 6, "score": 0, "title": "Emergence of ferroelectricity at a metal semiconductor transition in a 1T monolayer of MoS2.", "venue": "Physical review letters", "year": 2014 }, { "abstract": "Ferroelectric semiconductors, combining semiconduction, spontaneous polarization, and photo induced excitation, show great promise to enhance the performance of solar cells, pressure sensors, and photodetectors. Particularly, organic inorganic lead halide perovskite ferroelectrics have been explored for their prominent carrier transport properties and instinct structural tunability. Whereas, high concentration of toxic Pb is the potential stumbling block for their further application. Here, we present a lead free hybrid perovskite semiconductor, (C4H9NH3)2(NH3CH3)2Sn3Br10 (1) which exhibits a large spontaneous polarization of 11.76 mC cm 2 at room temperature. Significantly, 1 presents a spontaneous polar ordering transition as the better known perovskite ferroelectrics and exhibits ferroelectric phase transition behaviors. To our best known, 1 is the first example of Sn based hybrid perovskite semiconductor featuring ferroelec tric performances. Machanism studies reveal that such ferroelectricity can be attributable to the synergistic effects of ordering of organic cations and stereochemically active lone pair electrons induced distortion of inorganic octahe dra. This work provides an effective way to explore \"green\" ferroelectric semiconductors with potentially enhanced energy conversion efficiency.", "author_names": [ "Lina Li", "Xitao Liu", "Chao He", "Sasa Wang", "Chengmin Ji", "Xinyuan Zhang", "Zhihua Sun", "Sangen Zhao", "Maochun Hong", "Junhua Luo" ], "corpus_id": 210042358, "doc_id": "210042358", "n_citations": 25, "n_key_citations": 0, "score": 0, "title": "A Potential Sn Based Hybrid Perovskite Ferroelectric Semiconductor.", "venue": "Journal of the American Chemical Society", "year": 2020 }, { "abstract": "Abstract Emerging 2D electronic materials have shown great potential for regulating and controlling optoelectronic processes. A 2D ferroelectric semiconductor coupled with the piezo phototronic effect may bring unprecedented functional characteristics. Here, a heterojunction photodetector made of p Si/V doped ferroelectric ZnO 2D nanosheets (FESZ PD) is fabricated, and the ferroelectricity enhanced piezo phototronic effect on the photoresponse behavior of the FESZ PD is carefully investigated. By introducing the ferroelectricity and the piezo phototronic effect, improved current rectification performance is achieved and the photoresponse performance of the heterojunction is enhanced in a broad spectral range. The applied voltage bias during measurement naturally causes ferroelectric spontaneous polarizations to align, resulting in a change in band structure near the interface and the local piezo phototronic effect. The modulated energy band promotes the generation, separation, and transportation efficiency of photogenerated carriers greatly. Compared with the Si/ZnO 2D nanosheets photodetector without ferroelectricity under strain free conditions, the photoresponsivity R of the FESZ PD increases by 2.4 times when applying a 0.20%0 compressive strain at +1 V forward bias. These results confirm the feasibility of coupling the ferroelectricity with the piezo phototronic effect in 2D ferroelectric materials to enhance the photoresponse behavior, which provides a good way to enable the development of high performance electronic and optoelectronic devices.", "author_names": [ "Yejing Dai", "Changsheng Wu", "Zhiyi Wu", "Zhihao Zhao", "Li De Li", "Yang Lu", "Zhong Lin Wang" ], "corpus_id": 197620556, "doc_id": "197620556", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Ferroelectricity Enhanced Piezo Phototronic Effect in 2D V Doped ZnO Nanosheets", "venue": "Advanced science", "year": 2019 }, { "abstract": "The various structures of ferroelectric tunnel junctions (FTJs) are widely studied. Among them, metal ferroelectric semiconductor (MFS) FTJs show great tunneling electroresistance (TER) ratio by forming a depletion region. However, the poor ferroelectricity of hafnia on semiconductor electrodes degrades the TER ratio. This study employed high pressure annealing with forming gas to improve the ferroelectric properties of MFS FTJs. We achieved a high 2P_r value <inline formula> <tex math notation=\"LaTeX\"$47.54~\\mu \\text{c} /tex math>/inline formula>/cm<inline formula> <tex math notation=\"LaTeX\"{2} /tex math>/inline formula> and large TER ratio (22) in MFS FTJ for a 6 nm thick hafnia layer annealed at high pressure (200 atm) with forming gas. This work helps improve the quality of interface between a semiconductor and ferroelectric layer to increase the ferroelectricity of MFS stack devices.", "author_names": [ "Junghyeon Hwang", "Youngin Goh", "Sanghun Jeon" ], "corpus_id": 220834974, "doc_id": "220834974", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Effect of Forming Gas High Pressure Annealing on Metal Ferroelectric Semiconductor Hafnia Ferroelectric Tunnel Junction", "venue": "IEEE Electron Device Letters", "year": 2020 } ]

[ { "abstract": "Shrinking process windows for advanced processing of complex devices, sub 14nm, require advanced topography control. Within wafer topography variations impact the uniformity of subsequent layers and can affect yield. Process tools can generally control global uniformity across wafer, but are not well equipped to fine tune the local (reticle to reticle) topography. Advanced new process tools such as the Gas Cluster Ion Beam (GCIB) offer a promising path for improving topography within wafer and from wafer to wafer [1, 2] GCIB uses a highly localized focus beam controlled by location specific processing (LSP) algorithms to achieve the needed planarization corrections. In order to be effective, the LSP algorithms require wafer specific knowledge on the incoming topography distribution. The beam dwells in different locations on the wafer for different amounts of time in order to vary the amount of material removed. Therefore, the performance of local planarization tools depends on the availability and quality of the metrology data. Integrated scatterometry based metrology (IM) is the workhorse metrology enabler for inline APC (Advanced Process Control) and monitoring solutions for the Chemical Mechanical Planarization (CMP) and Reactive Ion Etching (RIE) processes. While maintaining equivalent performance to their standalone (SA) scatterometry siblings, IMs are typically mounted on the GCIB tool and dedicated to provide pre and post process measurements for wafers processed on the tool. They enable real time per wafer adjustments to within lot process knobs due to their proximity to the process.", "author_names": [ "Taher Kagalwala", "Ravi K Dasaka", "Michael V Aquilino", "Laertis Economikos", "Aron J Cepler", "Charles Kang", "Naren Yellai" ], "corpus_id": 28988580, "doc_id": "28988580", "n_citations": 5, "n_key_citations": 0, "score": 1, "title": "Integrated metrology's role in Gas Cluster Ion Beam etch", "venue": "2015 26th Annual SEMI Advanced Semiconductor Manufacturing Conference (ASMC)", "year": 2015 }, { "abstract": "Argon Gas Cluster Ion Beam (GCIB) sources have become very popular in XPS and SIMS in recent years, due to the minimal chemical damage they introduce in the depth profiling of polymer and other organic materials. These GCIB sources are therefore particularly useful for depth profiling polymer and organic materials, but also (though more slowly) the surfaces of inorganic materials such as semiconductors, due to the lower roughness expected in cluster ion sputtering compared to that introduced by monatomic ions. We have examined experimentally a set of five compound semiconductors, cadmium telluride (CdTe) gallium arsenide (GaAs) gallium phosphide (GaP) indium arsenide (InAs) and zinc selenide (ZnSe) and a high k dielectric material, hafnium oxide (HfO) in their response to argon cluster profiling. An experimentally determined HfO etch rate of 0.025 nm/min (3.95 x 10 2 amu/atom in ion) for 6 keV Ar gas clusters is used in the depth scale conversion for the profiles of the semiconductor materials. The a.", "author_names": [ "Anders J Barlow", "Jose F Portoles", "Peter J Cumpson" ], "corpus_id": 95609733, "doc_id": "95609733", "n_citations": 23, "n_key_citations": 0, "score": 0, "title": "Observed damage during Argon gas cluster depth profiles of compound semiconductors", "venue": "", "year": 2014 }, { "abstract": "We use optical, thermal, and electrical simulation to evaluate the effects of using varying amounts of undercut etch on wavelength scale and subwavelength metal clad semiconductor nanolasers (MCSELs) We find that as MCSEL diameter decreases, the optical performance becomes more sensitive to slight amounts of sidewall tilt. A modest amount of undercut (25% dramatically improves the optical performance, reducing modal threshold gain to 100 cm 1 or less for lasers with core radius of 225, 550, or 775 nm, even in the presence of significant sidewall tilt (20deg gain sidewall or 8deg pedestal sidewall tilt) Finally, we examine the effects of the increased undercut on nanolaser thermal performance and find that the increased resistive heating is insignificant near threshold, even for subwavelength nanolasers.", "author_names": [ "Janelle C Shane", "Qing Gu", "Alan Potterton", "Yeshaiahu Fainman" ], "corpus_id": 28571226, "doc_id": "28571226", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Effect of Undercut Etch on Performance and Fabrication Robustness of Metal Clad Semiconductor Nanolasers", "venue": "IEEE Journal of Quantum Electronics", "year": 2015 }, { "abstract": "We show that Au nanoparticles spontaneously move across the (001) surface of InP, InAs, and GaP when heated in the presence of water vapor. As they move, the particles etch crystallographically aligned grooves into the surface. We show that this process is a negative analogue of the vapor liquid solid (VLS) growth of semiconductor nanowires: the semiconductor dissolves into the catalyst and reacts with water vapor at the catalyst surface to create volatile oxides, depleting the dissolved cations and anions and thus sustaining the dissolution process. This VLS etching process provides a new tool for directed assembly of structures with sublithographic dimensions, as small as a few nanometers in diameter. Au particles above 100 nm in size do not exhibit this process but remain stationary, with oxide accumulating around the particles.", "author_names": [ "Babak Nikoobakht", "Andrew A Herzing", "Shin Muramoto", "Jerry Tersoff" ], "corpus_id": 206730281, "doc_id": "206730281", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Vapor Liquid Solid Etch of Semiconductor Surface Channels by Running Gold Nanodroplets.", "venue": "Nano letters", "year": 2015 }, { "abstract": "Abstract Reflectance anisotropy spectroscopy (RAS) can be used to monitor (reactive) ion etching (RIE) of semiconductor samples. We present results on the influence of the Cl2 content of the plasma gas on the RAS spectra during reactive ion etching. In a first step GaAs samples have been used and the RAS spectra are compared to results of secondary ion mass spectrometry (SIMS) on sample surfaces and depth profiles. In a second step a III V semiconductor multilayer system has been investigated using the time evolution of the average reflected intensity as an indication for the etch rate. In both cases usually even a high amount of Cl2 does not disturb the surface sensitivity of the RAS signal.", "author_names": [ "Lars Barzen", "Annika Kleinschmidt", "Johannes Strassner", "Christoph Doering", "Henning Fouckhardt", "W Bock", "Michael Wahl", "Michael Kopnarski" ], "corpus_id": 93187834, "doc_id": "93187834", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Influence of plasma composition on reflectance anisotropy spectra for in situ III V semiconductor dry etch monitoring", "venue": "", "year": 2015 }, { "abstract": "A Bayesian network (BN) based fault diagnosis framework for semiconductor etching equipment is presented. Suggested framework contains data preprocessing, data synchronization, time series modeling, and BN inference, and the established BNs show the cause and effect relationship in the equipment module level. Statistically significant state variable identification (SVID) data of etch equipment are preselected using principal component analysis (PCA) and derivative dynamic time warping (DDTW) is employed for data synchronization. Elman's recurrent neural networks (ERNNs) for individual SVID parameters are constructed, and the predicted errors of ERNNs are then used for assigning prior conditional probability in BN inference of the fault diagnosis. For the demonstration of the proposed methodology, 300 mm etch equipment model is reconstructed in subsystem levels, and several fault diagnosis scenarios are considered. BNs for the equipment fault diagnosis consists of three layers of nodes, such as root cause (RC) module (M) and data parameter (DP) and the constructed BN illustrates how the observed fault is related with possible root causes. Four out of five different types of fault scenarios are successfully diagnosed with the proposed inference methodology.", "author_names": [ "Javeria Muhammad Nawaz", "Muhammad Zeeshan Arshad", "Sang Jeen Hong" ], "corpus_id": 62611203, "doc_id": "62611203", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Fault Diagnosis in Semiconductor Etch Equipment Using Bayesian Networks", "venue": "", "year": 2014 }, { "abstract": "A method of fault detection and classification (FDC) for semiconductor manufacturing equipment e diagnostics using equipment data is presented. Detecting faulty processes, identifying any anomaly at their onsets, and rapidly classifying the root cause of the fault are crucial for maximizing equipment utilization in current semiconductor manufacturing; however, tool data acquired from production equipment contains much information that is often challenging to analyze due to its sheer volume and complexity. In this paper, modular neural network (MNN) modeling is presented as a method for fault detection modeling in plasma etching. Based on the result from the MNN modeling, a tool data set is grouped according to its related subsystems, and FDC is performed using Dempster Shafer (D S) theory to address the uncertainty associated with fault diagnosis. Subsystem level fault detections, such as radio frequency (RF) power source module, RF power bias module, gas delivery module, and process chamber module, are presented by combining related parameters, and successful fault detection is achieved. The evidential reasoning of RF probe is also beneficial for the detection of chamber leak simulation, and the classification of fault is made by further investigating voltage signal of RF probe. Successful fault detection in subsystem level with zero missed alarms was demonstrated using D S theory of evidential reasoning, and the classification for finding root cause of the fault is presented in the chamber leak fault simulation. We realized that successful FDC can be accomplished by combining various related information and by incorporating engineering expert knowledge.", "author_names": [ "Sang Jeen Hong", "Woo Yup Lim", "Taesu Cheong", "Gary S May" ], "corpus_id": 113021, "doc_id": "113021", "n_citations": 43, "n_key_citations": 2, "score": 0, "title": "Fault Detection and Classification in Plasma Etch Equipment for Semiconductor Manufacturing $e$ Diagnostics", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2012 }, { "abstract": "This article addresses a challenging resource constrained flow shop scheduling problem from automated wet etch stations (AWSs) in wafer fabrication of semiconductor manufacturing facilities by means of a constraint programming (CP) methodology. Wet etching in wafer fabrication is a difficult process considering the material handling limitations and mixed intermediate policies. The proposed integrated approach consists of both a CP model and an efficient search strategy in order to handle the different features of the process. The domain specific search strategy significantly improves the computational performance, a key aspect given the high combinatorial complexity of the problem. The search strategy objective is to avoid losing time due to early bad choices in the exploration and to produce good quality solutions with low computational effort. The applicability of the proposed integrated CP methodology is successfully tested with several examples taken from the literature, featuring a different number o.", "author_names": [ "Luis Zeballos", "Pedro M Castro", "Carlos A Mendez" ], "corpus_id": 101177540, "doc_id": "101177540", "n_citations": 32, "n_key_citations": 1, "score": 0, "title": "Integrated Constraint Programming Scheduling Approach for Automated Wet Etch Stations in Semiconductor Manufacturing", "venue": "", "year": 2011 }, { "abstract": "Abstract This work addresses the short term scheduling of one of the most critical stages in the semiconductor industry, the automated wet etch station (AWS) An efficient MILP based computer aided tool is developed in order to achieve a proper synchronization between the activities of sequential chemical and water baths and limited automated wafer's lot transfer devices. The major goal is to find the optimal integrated schedule that maximizes the whole process productivity without generating wafer contamination. Several examples are successfully solved to illustrate the capabilities of the proposed method.", "author_names": [ "Adrian M Aguirre", "Carlos A Mendez", "Pedro M Castro" ], "corpus_id": 14728417, "doc_id": "14728417", "n_citations": 24, "n_key_citations": 4, "score": 0, "title": "A novel optimization method to automated wet etch station scheduling in semiconductor manufacturing systems", "venue": "Comput. Chem. Eng.", "year": 2011 }, { "abstract": "The objective of this paper is to develop a wafer by wafer fault detection model for a semiconductor etch tool operating in a worksite situation in which the tool parameter traces are correlated and drift slowly from an initial recipe setting. Process drift is a common occurrence in many processes because of the aging of tool components. The proposed fault detection model compares the entire trace structures of the tool parameters with reference templates by using an improved DTW (dynamic time warping) algorithm, and it performs a T 2 based multivariate analysis with the structure similarity scores created by the improved DTW. In addition, to adapt to the process drift, a recursive T 2 update procedure with an optimal correction factor is incorporated in the model. The optimal correction factor is derived using the Kalman filtering technique. Experiments using the data collected from a worksite reactive ion etching process demonstrate that the performance of the proposed fault detection model is very encouraging.", "author_names": [ "Jong Myoung Ko", "Chang Ouk Kim" ], "corpus_id": 109407921, "doc_id": "109407921", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "A multivariate parameter trace analysis for online fault detection in a semiconductor etch tool", "venue": "", "year": 2012 } ]

[ { "abstract": "The strain relaxation process in wafer bonded semiconductor heterostructures is numerically investigated, in contrast to those formed by epitaxial growth. A kinetic model of strain relaxation in semiconductor layers is re established for highly lattice mismatched heterostructures. Numerical simulations are then performed by using the model to analyze the time evolution of the strain, the strain rate, and the misfit dislocation density. The calculation results present a slow strain relaxation behavior in the lattice mismatched heterostructures wafer bonded at lower temperatures than those for epitaxial growth, to suppress the thermodynamically preferred dislocation generation by sustaining the material system at a metastable state. The time constant of strain relaxation in a typical range of wafer bonding temperatures, normalized by the melting temperature, of 0.2 0.4 is found to be 3 x 105 2 x 1021 s for a lattice mismatch of 0.04. This relaxation time contrasts with 14 s for the case of heteroepitaxy at a typical normalized temperature of 0.6, thus evidencing the nonequilibrium crystalline stability in wafer bonding.", "author_names": [ "Katsuaki Tanabe" ], "corpus_id": 234853845, "doc_id": "234853845", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Strain relaxation in semiconductor wafer bonding", "venue": "", "year": 2021 }, { "abstract": "Changes in the strain relaxation of semiconductor films due to growth on a thin epitaxial template bonded via a borosilicate glass to a mechanical handle wafer have been observed. Akinetic analysis of the mechanical decoupling between the film/template heterostructure and the handle wafer is developed in order to estimate and evaluate the contribution of glass viscous deformation to the observed strain relaxation. The thickness and elastic constants of the template and film, the thickness and viscosity of the bonding media, and the lateral dimension of the bonded structure are included in this model. Based on this model, the viscous flow of the glass is unlikely to have played a role in previous observations of changes in film strain relaxation due to growth on glass bonded substrates. The calculations are used in conjunction with simple expressions for the temperature and composition dependence of borosilicate glass viscosity to result in design guidelines for substrate structures and annealing schedules in which the viscous flow of a borosilicate glass will contribute to the strain relaxation of a lattice mismatched film.", "author_names": [ "Peter D Moran", "Thomas F Kuech" ], "corpus_id": 94642071, "doc_id": "94642071", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Kinetics of strain relaxation in semiconductor films grown on borosilicate glass bonded substrates", "venue": "", "year": 2001 }, { "abstract": "Elastically strain relaxed GaAs/In0.08Ga0.92As/GaAs heterostructures on GaAs(001) substrates were fabricated. Pseudomorphic heterostructures grown by MOCVD were patterned using conventional photolithography and a sacrificial AlAs layer was removed by selective etching. As etching proceeds and the GaAs/InGaAs/GaAs structure is released from the substrate, elastic strain relaxation occurs and the strain relaxed structures are weakly bonded in place to the substrate. The bond between the strain relaxed structure and the substrate was then strengthened by annealing under conditions similar to those used for whole wafer bonding of GaAs. The strain, composition and thickness of the layers were determined using high resolution X ray diffraction and the sample surface quality was examined using atomic force microscopy. The degree of strain relaxation of the InGaAs layer is determined by the relative thickness of the GaAs and InGaAs layers in agreement with a force balance model. The increase in the in plane lattice parameter of the bonded GaAs/In0.08Ga0.92As/GaAs structures as compared to GaAs is 0.25 0.44%", "author_names": [ "D Lloyd Owen" ], "corpus_id": 137565062, "doc_id": "137565062", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "IN PLACE BONDING OF III V SEMICONDUCTOR HETEROSTRUCTURES", "venue": "", "year": 2009 }, { "abstract": "We have recently found a novel and significant application for the wafer bonding technology. We demonstrated that by bonding an ultra thin layer of semiconductor to a bulk crystal with a rotational angle along their surface normal, this new structure can achieve interesting behaviors as a compliant substrate. When heteroepitaxial layers are grown on such twist bonded substrates, the bonded thin layer is plastically deformed to relax the strain before threading dislocations are nucleated in the heteroepitaxial layer. This is a new and energetically more favorable way for lattice strain relaxation and is unique to the twist bonded structure. We found that this concept can be applied to many semiconductors such as GaAs and Si to form compliant substrates where heteroepitaxy of exceedingly large lattice mismatch (e.g. 15% can be grown without defects. This implies that twist bonded compliant substrates may, to a large extent, function as a universal substrate for growth of high quality materials of nearly any lattice constant.", "author_names": [ "Z H Zhu", "Felix Ejeckam", "Zhenjun Zhang", "Jing-wei Zhang", "Yi Qian", "Yu-hwa Lo" ], "corpus_id": 123040476, "doc_id": "123040476", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Wafer bonding and its application on compliant universal (CU) substrates", "venue": "Conference Proceedings. LEOS '97. 10th Annual Meeting IEEE Lasers and Electro Optics Society 1997 Annual Meeting", "year": 1997 }, { "abstract": "Abstract This chapter deals with the monolithic integration of InGaAs semiconductor on (001) oriented Si substrate. This starts with a brief introduction to III V semiconductor epitaxy, the effect of strain, and the relaxation mechanisms. An overview of the different structural defects' families is also included in the section. In a second part, the two most popular III V growth techniques that are molecular beam epitaxy and metal organic vapor phase epitaxy are compared. The main challenge in the heterogeneous integration of InGaAs on Si resides in the material mismatch between both semiconductors that results in the high density generation of crystalline defects. In this chapter, several options such as strain relaxed buffers, wafer bonding, epitaxial lateral growth, and selective area growth have been considered to reduce the defect density in III V compounds on Si, which will be reviewed. Finally, a rich literature completes the chapter.", "author_names": [ "C Merckling" ], "corpus_id": 139953661, "doc_id": "139953661", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Monolithic Integration of InGaAs on Si(001) Substrate for Logic Devices", "venue": "", "year": 2018 }, { "abstract": "The fabrication of ultrathin strained silicon directly on insulator is demonstrated and the thermal stability of these films is investigated. Ultrathin ~13 nm) strained silicon on insulator layers were fabricated by epitaxial growth of strained silicon on relaxed SiGe, wafer bonding, and an etch back technique employing two etch stop layers for improved across wafer thickness uniformity. Using 325 nm Raman spectroscopy, no strain relaxation is observed following rapid thermal annealing of these layers to temperatures as high as 950 degC. The thermal stability of these films is promising for the future fabrication of enhanced performance strained Si ultrathin body and double gate metal oxide semiconductor field effect transistors.", "author_names": [ "T S Drake", "Cait Ni Chleirigh", "Minjoo Lawrence Lee", "Arthur J Pitera", "Eugene A Fitzgerald", "Dimitri A Antoniadis", "Dalaver Hussain Anjum", "Jie-ping Li", "Robert Hull", "N Klymko", "Judy L Hoyt" ], "corpus_id": 119935734, "doc_id": "119935734", "n_citations": 40, "n_key_citations": 0, "score": 0, "title": "Effect of rapid thermal annealing on strain in ultrathin strained silicon on insulator layers", "venue": "", "year": 2003 }, { "abstract": "In this letter, the relaxation of strained rectangular islands on compliant substrates is used to achieve semiconductor thin films with either uniaxial stress or uniaxial strain in the plane of the film over an area of tens of microns. The work is demonstrated using silicon and silicon germanium alloy single crystal thin films, with uniaxial strain values approaching 1% The biaxially strained SiGe or SiGe/Si films on borophosphorosilicate glass (BPSG) were fabricated by a wafer bonding and layer transfer process. When the viscosity of BPSG drops at high temperatures for short times, films patterned in a rectangular shape can move laterally to relieve stress only in one in plane direction. Thus one can tailor the strain from biaxial to uniaxial in the thin films.", "author_names": [ "Haizhou Yin", "Rebecca L Peterson", "Karl D Hobart", "Sean R Shieh", "Thomas S Duffy", "James C Sturm" ], "corpus_id": 120301076, "doc_id": "120301076", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Tunable uniaxial vs biaxial in plane strain using compliant substrates", "venue": "", "year": 2005 }, { "abstract": "InGaSb on insulator (InGaSb OI) and InAs/InGaAs/InAs on insulator (InAs/InGaAs OI) structures have been realized on Si by a direct wafer bonding (DWB) technology using atomic layer deposition Al2O3. While strain introduced in InGaSb channel layers grown on InAs can enhance the hole mobility of the Sb based channel layers, a difficult issue of fabricating InGaSb OI wafers is to obtain a smooth InGaSb surface, which is mandatory for wafer bonding. In this study, the surface of a 20 nm thick In0.185Ga0.815Sb channel grown on an InAs (100) substrate and an InAs (2.5 nm)/In0.185Ga0.815Sb (20 nm)/InAs (2.5 nm) channel with a 20 nm thick GaSb buffer layer grown on an InAs (100) substrate by metal organic chemical vapor deposition have a root mean square of the surface roughness as low as 0.16 and 0.22 nm, respectively, over a scan area of 10 x 10 mm2, which are smooth enough to employ the wafer bonding. As a result, the fabrication of the InGaSb OI wafers by the DWB and the operation of InGaSb OI p channel metal oxide semiconductor field effect transistors (p MOSFETs) by using the DWB wafers are demonstrated. Also, the performance of InGaSb OI p MOSFETs is found to be improved by inserting ultrathin InAs layers between InGaSb and insulating buried oxide layers. An InGaSb OI and an InAs/InGaAs OI p MOSFET under the accumulation mode operation exhibit a peak mobility of ~161 and ~273 cm2/V s, respectively. The channel hole mobility of the InGaSb OI p MOSFET is higher than that of the GaSb on insulator (GaSb OI) p MOSFET and can exceed that of Si p MOSFETs.InGaSb on insulator (InGaSb OI) and InAs/InGaAs/InAs on insulator (InAs/InGaAs OI) structures have been realized on Si by a direct wafer bonding (DWB) technology using atomic layer deposition Al2O3. While strain introduced in InGaSb channel layers grown on InAs can enhance the hole mobility of the Sb based channel layers, a difficult issue of fabricating InGaSb OI wafers is to obtain a smooth InGaSb surface, which is mandatory for wafer bonding. In this study, the surface of a 20 nm thick In0.185Ga0.815Sb channel grown on an InAs (100) substrate and an InAs (2.5 nm)/In0.185Ga0.815Sb (20 nm)/InAs (2.5 nm) channel with a 20 nm thick GaSb buffer layer grown on an InAs (100) substrate by metal organic chemical vapor deposition have a root mean square of the surface roughness as low as 0.16 and 0.22 nm, respectively, over a scan area of 10 x 10 mm2, which are smooth enough to employ the wafer bonding. As a result, the fabrication of the InGaSb OI wafers by the DWB and the operation of InGaSb OI p channel metal.", "author_names": [ "Masafumi Yokoyama", "Haruki Yokoyama", "Mitsuru Takenaka", "Shinichi Takagi" ], "corpus_id": 126716240, "doc_id": "126716240", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "InGaSb on insulator p channel metal oxide semiconductor field effect transistors on Si fabricated by direct wafer bonding", "venue": "Journal of Applied Physics", "year": 2019 }, { "abstract": "Here the novel direct heteroepitaxial growth method of a 3D heteroepitaxial system is demonstrated on a 3D substrate, CdTe (111)/Al2 O3 (0001) which forms a spontaneous vdW like bond at the interface, instead of the two 3D crystals being strongly bound. Despite a large lattice mismatch, the thin films are single crystals and maintain high quality due the compliance of the interface which accommodates strain. This weak bonding interface is accomplished by the self assembly of a pseudomorphic chalcogenide layer on the sapphire surface during growth. Since the vdW like interface forms spontaneously in situ during growth, it is easily scalable to large wafer sizes, without the need to layer transfer 2D materials onto the growth substrate for remote epitaxy. Further, the weak adhesion of the films on the substrates allow for epitaxial film transfer to a variety of other substrates, leaving the original growth substrate for future reuse. This type of 3D/3D vdW like interface is exploitable as a compliant interlayer for additional epitaxy, and may even be observable directly in other material systems grown on complex oxides, allowing for the production of large area high quality freestanding and layer transferred epitaxial devices for material systems not currently possible by conventional processing techniques.", "author_names": [ "Stephen M Jovanovic", "Hesham M El-Sherif", "Nabil Bassim", "John Stephen Preston" ], "corpus_id": 224811299, "doc_id": "224811299", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Spontaneous Relaxation of Heteroepitaxial of Thin Films by van der Waals Like Bonding on Te Terminated Sapphire Substrates.", "venue": "Small", "year": 2020 }, { "abstract": "Different methods to introduce strain in thin silicon device layers are presented. Uniaxial strain is introduced in CMOS devices by process induced stressors allowing the local generation of tensile or compressive strain in the channel region of MOSFETs. Biaxial strain is introduced by growing thin silicon layer on SiGe buffer and transferring it to an oxidized silicon substrates. The latter forms strained silicon on insulator (SSOI) wafer characterized by tensile strain only. Future CMOS device technologies require the combination of the global strain of SSOI substrates with local stressors to increase the device performance.", "author_names": [ "Manfred Reiche", "O Moutanabbir", "Cameliu Himcinschi", "Silke H Christiansen", "Winfried Erfurth", "Ullrich Gosele", "Siegfried Mantl", "Dan Buca", "Q T Zhao", "Roger Loo", "Danh Nguyen", "F Muster", "Matthias Petzold" ], "corpus_id": 110776807, "doc_id": "110776807", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Strained Silicon on Wafer Level by Waferbonding: Materials Processing, Strain Measurements and Strain Relaxation", "venue": "", "year": 2008 } ]

[ { "abstract": "Photoreduction of CO2 to valuable fuels with semiconductor photocatalysts is a good solution to the problems of global warming and energy crisis. Creation of hybrid nanomaterials with hierarchical and/or heterojunction structures is beneficial to develop efficient photocatalysts for CO2 reduction. Herein we present a convenient method to obtain a hybrid photocatalyst consisting of MnS and In2S3 nanosheets with assembled hierarchical structures through using Mn2+ loaded MIL 68(In) submicro rods as templates. Owing to the dispersive Mn2+ and In3+ ions in templates, numerous small p n heterojunctions of MnS/In2S3 could be simultaneously produced in each hierarchical particle. The p type MnS and n type In2S3 with an original type II band alignment can create a stronger built in electric field after the formation of p n heterojunctions, which is favorable for charge separation and migration to catalyst surface. The prepared MnS/In2S3 heterojunctions show an 4 fold higher photocatalytic activity toward CO2 reduction than pristine MnS and In2S3. The MnS/In2S3 hierarchical structures were well characterized and their working mechanism was explored. This work demonstrates a facile strategy to create efficient hybrid photocatalysts with both hierarchical structures and p n heterojunctions for photocatalytic applications.", "author_names": [ "Jun Tan", "Mengshi Yu", "Zhenzhi Cai", "Xiaodan Lou", "Jun Wang", "Zhengquan Li" ], "corpus_id": 231584266, "doc_id": "231584266", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "MOF derived synthesis of MnS/In2S3p n heterojunctions with hierarchical structures for efficient photocatalytic CO2 reduction.", "venue": "Journal of colloid and interface science", "year": 2020 }, { "abstract": "Abstract The conversion of CO2 into clean energy by exploiting porous hollow structure photocatalysts with superior activity is of worldwide interest. In this work, ZnO/NiO porous hollow spheres with sheet like subunits were obtained by calcination of the Ni Zn bimetallic organic frameworks (MOFs) The prepared ZnO/NiO composites exhibited enhanced photocatalytic activity for CO2 recondition, and the highest CH3OH evolution rate was observed for sample ZN 30, which was about 3 times than that of pure ZnO. It is believed that the heterogeneous n type ZnO and p type NiO produced from the decomposition of heterothallic Zn Ni MOFs are homogeneously mixed together, resulting in the formation of many p n heterojunctions which could be benefit to the charge separation. Furthermore, such porous hollow structure could increase the specific surface area, CO2 uptake capacity as well as the light absorption property. Thus, the composite photocatalyst exhibited excellent photocatalytic CO2 reduction performance. This work provides a new insight to finely design and fabricate novel heterogeneous composite with hollow structure in photocatalysis by using multi metallic organic frameworks as the precursors.", "author_names": [ "Shiqiang Chen", "Jiaguo Yu", "Jun Zhang" ], "corpus_id": 139968055, "doc_id": "139968055", "n_citations": 47, "n_key_citations": 0, "score": 0, "title": "Enhanced photocatalytic CO2 reduction activity of MOF derived ZnO/NiO porous hollow spheres", "venue": "", "year": 2018 }, { "abstract": "Abstract Improving the visible light response and efficient separation of electron hole pairs play vital roles in commonly used TiO2 photocatalyst for VOCs degradation. Herein, N doped mesoporous carbon encapsulated anatase rutile phase junction TiO2 (TiO2@C N(x) was successfully synthesized via the pyrolysis of a representative amine functionalized Ti based MOF, NH2 MIL 125, under the atmosphere of Ar and subsequent CO2 treatment. Our synthesis stragety was based on the rational regulation of the formation of TiO2 phase junction and the decomposition of amorphous carbon onto the TiO2@C N (without subsequent CO2 process) using CO2 as both anatase rutile phase transformation promoter and mild oxidant. Compared with TiO2@C N, TiO2@C N(x) nanocomposites with subsequent CO2 process exhibit significantly improved photocatalytic activity as well as mineralization efficiencies. For example, the mineralization efficiency reached 51.9% at 62.4% of styrene degradation within 240 min of visible light irradiation by using the optimal TiO2@C N(30) nanocomposites as compared with only 19.7% mineralization efficiency at 31.0% of styrene degradation under the same conditions of TiO2@C N. Furthermore, the primary radicals involved in degradation of VOCs was identified by electron paramagnetic resonance spectroscopy, and the possible degradation intermediates were also monitored by means of proton transfer reaction time of flight mass spectrometry (PTR ToF MS) Finally, the radicals involved degradation reaction mechanism was also tentatively proposed.", "author_names": [ "Jiangyao Chen", "Meicheng Wen", "Guiying Li", "Taicheng An" ], "corpus_id": 108526524, "doc_id": "108526524", "n_citations": 53, "n_key_citations": 0, "score": 0, "title": "Highly efficient visible light driven photocatalytic degradation of VOCs by CO2 assisted synthesized mesoporous carbon confined mixed phase TiO2 nanocomposites derived from MOFs", "venue": "Applied Catalysis B: Environmental", "year": 2019 }, { "abstract": "As the main component of syngas, reducing CO2 to CO with high selectivity through photocatalysis could provide a sustainable way to alleviate energy shortage issues. Developing a photocatalytic system with low cost and high performance that is environmentally friendly is the ultimate goal towards CO2 photoreduction. Herein, an efficient and economic three component heterojunction photocatalyst is designed and fabricated for converting CO2 to CO in the absence of organic sacrificial agents. The heterojunction is made of Cu2 x S nanotubes coated with a carbon layer (C Cu2 x S) and g C3 N4 By using the classical MOF material HKUST 1 as a precursor, hollow tubular like metal sulfides (C Cu2 x S) with carbon coating were synthesized and further loaded on g C3 N4 forming a three component heterojunction C Cu2 x S@g C3 N4 The carbon coat in C Cu2 x S@g C3 N4 acts as an electron reservoir, which facilitates electron hole pair separation. The optimized C Cu2 x S@g C3 N4 acted as a photocatalyst in CO2 reduction with a high reactivity of 1062.6 mmol g 1 and selectivity of 97 Compared with bare g C3 N4 (158.4 mmol g 1 and C Cu2 x S, the reactivity is nearly 7 and 23 fold enhanced and this CO generation rate is higher than most of the reported Cu2 S or g C3 N4 composites under similar conditions. The prominent activity may result from enhanced light adsorption and effective charge separation. This work might open up an alternative method for the design and fabrication of high performance and low cost photocatalysts for efficiently and durably converting CO2 to CO with high selectivity.", "author_names": [ "Cheng-Ying Hu", "Jie Zhou", "Chun-Yi Sun", "Meng Chen", "Xinlong Wang", "Zhongmin Su" ], "corpus_id": 53027421, "doc_id": "53027421", "n_citations": 30, "n_key_citations": 0, "score": 0, "title": "HKUST 1 Derived Hollow C Cu2 x S Nanotube/g C3 N4 Composites for Visible Light CO2 Photoreduction with H2 O Vapor.", "venue": "Chemistry", "year": 2019 }, { "abstract": "A new microporous robust zirconium metal organic framework (Zr MOF) NNU 28, has been synthesized and employed as a visible light photocatalyst for carbon dioxide (CO2) reduction to produce formate. NNU 28 is constructed by using a visible light responsive organic ligand derived from an anthracene group. Studies reveal that the as prepared Zr MOF shows desirable characteristics including excellent chemical and thermal stability, high CO2 uptake, broad band visible light absorption and efficient photoinduced charge generation. Remarkably, NNU 28 is highly efficient for visible light driven CO2 reduction with a formate formation rate of 183.3 mmol h 1 mmolMOF 1, which is among the highest performances of Zr MOFs. Both photocatalytic experiments and electron paramagnetic resonance (EPR) studies reveal that both the inorganic building unit Zr6 oxo cluster and the anthracene based ligand contribute to the highly efficient photocatalysis of CO2 reduction. The dual photocatalytic routes are demonstrated here to be more efficient for visible light driven CO2 photoreduction than that typically relying on a ligand to metal charge transfer process, illustrating a new strategy to design and synthesize novel visible light photocatalysts for CO2 reduction with high efficiency.", "author_names": [ "Dashu Chen", "Hongzhu Xing", "Chungang Wang", "Zhongmin Su" ], "corpus_id": 102023864, "doc_id": "102023864", "n_citations": 120, "n_key_citations": 0, "score": 0, "title": "Highly efficient visible light driven CO2 reduction to formate by a new anthracene based zirconium MOF via dual catalytic routes", "venue": "", "year": 2016 }, { "abstract": "Titania exhibits unique photophysical and chemical properties and can be used for potential applications in the field of photocatalysis. The control of TiO2 in terms of phase, shape, morphology, and especially nanoscale synthesis of TiO2 particles still remains a challenge. Ti containing metal organic frameworks (MOFs) such as MIL 125, can be used as sacrificial precursors to obtain TiO2 materials with diverse phase compositions, morphologies, sizes, and surface areas. MIL 125 is composed of Ti/O clusters as the secondary building units (SBUs) bridged by 1,4 benzenedicarboxylate (bdc) In this study, preformed and surfactant stabilized gold nanoparticles (GNPs) were deposited onto the surface of amino functionalized NH2 MIL 125 during solvothermal synthesis. Targeted gold/titania nanocomposites, GNP/TiO2, were fabricated through the pyrolysis of GNP/NH2 MIL 125 nanocrystals. The modification of TiO2 with GNPs significantly increased the photocatalytic activity of the MOF derived TiO2 material for the re.", "author_names": [ "Kira Khaletskaya", "Anna Pougin", "Raghavender Medishetty", "Christoph Rosler", "Christian Wiktor", "Jennifer Strunk", "Roland A Fischer" ], "corpus_id": 100354588, "doc_id": "100354588", "n_citations": 90, "n_key_citations": 1, "score": 0, "title": "Fabrication of Gold/Titania Photocatalyst for CO2 Reduction Based on Pyrolytic Conversion of the Metal Organic Framework NH2 MIL 125(Ti) Loaded with Gold Nanoparticles", "venue": "", "year": 2015 }, { "abstract": "In this contribution we propose an alternative catalytic system based on MOF derivatives and small pore zeolites for the selective conversion of CO2 into light olefins, using the lowest metal loadings and highest GHSV reported in literature. The catalyst synthesis involves deriving In Zr oxides from MOFs containing these metals in their structure, i. e. (Zr)UiO 67 bipy In, via direct calcination in the presence of the zeolite, avoiding co precipitation, washing and mixing steps. This effectively creates a truly bifunctional In Zr zeolite catalyst, opposed to physical mixtures of two catalysts using different precursors. The good dispersion and low loadings of the MOF derived In Zr oxide supplemented with the strong acidity of chabazite type zeolites allows to couple the activation of CO2 with C C coupling, obtaining space time yields of 0.1 mol of CO2 converted to light olefins per gram of In per hour at 375 degC, under the GHSV conditions employed.", "author_names": [ "Nuria Martin", "Ander Portillo", "Ainara Ateka", "Francisco G Cirujano", "Lide Oar-Arteta", "Andres Tomas Aguayo", "Michiel Dusselier" ], "corpus_id": 225411440, "doc_id": "225411440", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "MOF derived/zeolite hybrid catalyst for the production of light olefins from CO2", "venue": "", "year": 2020 }, { "abstract": "Abstract Recent research in catalyst development for CO2 methanation has been focussing on the design of nanostructures with high porosity and better redox properties. Herein, nanostructured Ce0.8Zr0.2O2 mixed oxide support was prepared by a metal organic framework (MOF) template approach and its properties were well compared with a similar catalyst prepared by a conventional coprecipitation (CP) method. The MOF template approach resulted in the production of a nanoporous Ce0.8Zr0.2O2 support with improved redox properties compared to the coprecipitated Ce0.8Zr0.2O2. The prepared support was then decorated with Co3O4 nanoparticles and tested in CO2 methanation reaction. At 320 degC, 1.5 MPa and GHSV 15,000 mL g 1 h 1, the Co/Ce0.8Zr0.2O2 catalyst prepared by MOF template method achieved far better CO2 conversion (81.2% and improved CH4 selectivity (99% than the catalyst prepared by CP method (48.7% CO2 conversion and 97% CH4 selectivity) The long time presence of the MOF derived Co/Ce0.8Zr0.2O2 catalyst on the stream proved its resistance towards sintering, which may be ascribed to the fine dispersion of Co3O4 nanoparticles as well as their excellent integration in the network of nanoporous Ce0.8Zr0.2O2.", "author_names": [ "Deshetti Jampaiah", "Devaiah Damma", "Anastasios Chalkidis", "Perala Venkataswamy", "Suresh Kumar Bhargava", "Benjaram M Reddy" ], "corpus_id": 219490297, "doc_id": "219490297", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "MOF derived ceria zirconia supported Co3O4 catalysts with enhanced activity in CO2 methanation", "venue": "", "year": 2020 }, { "abstract": "Nanostructured N doped TiO2 photocatalyst has been prepared via a new approach from Ti based MOF[NH2 MIL 125(Ti) precursor. The success of N doping enhances light absorption and narrows the bandgap. Moreover, the as prepared nanostructure is constructed with tiny nanoparticles and resembles a pie like morphology inherited from the MOF, which accelerates electron transfer. Hence, as a photocatalyst for the degradation of methylene blue(MB) under visible light irradiation, the N doped TiO2(N TiO2) nanostructure shows higher photocatalytic activity with a reaction rate constant of 0.018 min 1 than that of the TiO2 P25 and TiO2 under the visible light.", "author_names": [ "Yilei He", "Xiang Zhang", "Yanze Wei", "Xiaoyu Chen", "Zumin Wang", "Ranbo Yu" ], "corpus_id": 218670804, "doc_id": "218670804", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Ti MOF Derived N Doped TiO2 Nanostructure as Visible light driven Photocatalyst", "venue": "Chemical Research in Chinese Universities", "year": 2020 }, { "abstract": "Copper based metal organic frameworks (MOFs) and their derivatives have been attempted to drive CO2 electroreduction, whereas they still suffered from obvious drawbacks like poor selectivity and durability. Here, Cu_btc (btc benzene 1,3,5 tricarboxylate) derived Cu2O/Cu anchored in nitrogen doped porous carbon framework (Cu2O/Cu@NC) was prepared for CO2 electroreduction. The Cu2O/Cu@NC 800 (carbonizing Cu_btc at 800 degC) produced formate and ethanol concurrently with overpotential as low as ~380 mV. However, it exhibited higher selectivity towards formate against ethanol, with the maximum formate faradaic efficiencies 70.5 at 0.68 V versus reversible hydrogen electrode (RHE) which was 1.79 and 1.84 times higher than that of Cu2O/Cu@NC 700 and Cu2O/Cu@NC 900. This superior performance maintained stable over 30 h. The enhancement in activity and selectivity was attributed to (i) higher Cu content and well dispersed Cu2O/Cu nanoparticles inside carbon frameworks which provided abundant active reaction sites, and (ii) higher content of N doped into the Cu2O/Cu lattice to possibly facilitated *OCHO generation. These findings provided a convenient strategy to enhance the activity and selectivity of catalysts for efficient CO2 electroreduction.", "author_names": [ "Da Li", "Tongtong Liu", "Zhengyu Yan", "Liang Zhen", "Jia Xiang Liu", "Jing Wu", "Yujie Feng" ], "corpus_id": 210862822, "doc_id": "210862822", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "MOF derived Cu2O/Cu nanospheres anchored in nitrogen doped hollow porous carbon framework for increasing the selectivity and activity of electrochemical CO2 to formate conversion.", "venue": "ACS applied materials interfaces", "year": 2020 } ]

[ { "abstract": "This work examines the metal ferroelectric insulator semiconductor (MFIS) negative capacitance FinFET (NC FinFET) based VLSI subsystem level logic circuits. With the aid of a short channel NC FinFET compact model, we confirm the functionality and determine the standby power/switching energy/delay performance of logic circuits (5 stage inverter and 4 bit Manchester carry chain (MCC) adder) employing 14nm ULP NC FinFETs versus FinFETs. We show that the inverse $V_{ds} dependency of threshold voltage (V_{T} also known as the negative DIBL, of NCFET is not only acceptable but also beneficial for the speed performance of both the static and pass transistor logic (PTL) circuits, especially for the PTL at low $V_{DD}", "author_names": [ "Wei-Xiang You", "Pin Su", "Chenming Calvin Hu" ], "corpus_id": 61809533, "doc_id": "61809533", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Evaluation of NC FinFET Based Subsystem Level Logic Circuits Using SPICE Simulation", "venue": "2018 IEEE SOI 3D Subthreshold Microelectronics Technology Unified Conference (S3S)", "year": 2018 }, { "abstract": "SRAM plays an integral role in the power, performance, and area of a mobile system on a chip. To achieve low power and high density, extreme ultraviolet (EUV) technology is adopted for the 7nm FinFET technology [3 4] Conventional ArF immersion with a single exposure for an extreme high resolution patterning shows the limitation of lithographic patterning. Therefore, multi patterning lithographic technique is applied to support a high resolution lithography. However, this also includes process variations due to using multi pattering masks. Alternatively, EUV offers competitive scaling with a single mask with the benefit of smaller wavelength, which provides smaller process variation with less additional pattering. Figure 11.2.1 shows a 7nm EUV FinFET 6T high density (HD) SRAM bitcell with an area of 0.026msi2. The pull up, pass gate, and pull down ratios are 1:1:1 for high density and low power applications. Another benefit of EUV technology also features a bi directional metal layer with a scaled pitch that provides an extra degree of freedom for signal and power routing. Figure 11.2.2 highlights EUV benefits in accordance with bi directional metals. A uni directional metal layer requires different metal layer to connect two nets, and have no choice but to support the limited via between two perpendicular metal lines with the limited metal width. A wider metal allows placement of more vias between the metal lines, but it does not demonstrate optimum Power, Performance, and Area (PPA) with redundant parasitic capacitance. However, EUV provides bi directional metal lines, where the different layers of metal are coherent in the same direction. Therefore, more vias can be placed to reduce the IR drop with smaller parasitic capacitance and resistance. Figure 11.2.2 illustrates the delay impact versus stacked via distance in a standard cell array. It shows that the timing penalty is directly proportional to the stacked via distance in a uni directional metal routing.", "author_names": [ "Taejoong Song", "Jonghoon Jung", "Woojin Rim", "Hoonki Kim", "Yongho Kim", "Changnam Park", "Jeongho Do", "Sunghyun Park", "Sungwee Cho", "Hyuntaek Jung", "Bongjae Kwon", "Hyun-Su Choi", "Jaeseung Choi", "Jong Shik Yoon" ], "corpus_id": 3854996, "doc_id": "3854996", "n_citations": 19, "n_key_citations": 3, "score": 0, "title": "A 7nm FinFET SRAM using EUV lithography with dual write driver assist circuitry for low voltage applications", "venue": "2018 IEEE International Solid State Circuits Conference (ISSCC)", "year": 2018 }, { "abstract": "A 16nm configurable pass gate bit cell register file allows a direct comparison of NFET versus PFET pass gate bit cells for early technology evaluation. The configurable pass gate enables either a transmission gate (TG) an NFET pass gate, or a PFET pass gate. From silicon test chip measurement, the register file with PFET pass gate bit cells achieves a 33% minimum supply voltage (VMIN) reduction in a 16nm FinFET technology and a 40% VMIN reduction in an enhanced 16nm FinFET technology as compared to a register file with NFET pass gate bit cells. Test chip measurements highlight the superior benefits of the PFET drive current relative to the NFET drive current at low voltages. The VMIN improvement with a PFET pass gate bit cell represents a paradigm shift from traditional CMOS circuit design practices.", "author_names": [ "Jihoon Jeong", "Francois Atallah", "Hoan Nguyen", "Josh Puckett", "Keith A Bowman", "David Hansquine" ], "corpus_id": 12003539, "doc_id": "12003539", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "A 16nm configurable pass gate bit cell register file for quantifying the VMIN advantage of PFET versus NFET pass gate bit cells", "venue": "2015 IEEE Custom Integrated Circuits Conference (CICC)", "year": 2015 }, { "abstract": "BACKGROUND AND PURPOSE Subclinical hepatic encephalopathy (SHE) is frequently reported on single photon emission computed tomography (SPECT) but is rarely described with magnetic resonance (MR) techniques. This study aimed to investigate hemodynamic changes in brain basal ganglia in patients with SHE using dynamic susceptibility contrast (DSC) enhanced MR perfusion imaging. METHODS Twelve patients with SHE and ten age and education matched volunteers agreed to undergo MR examination. The scanning protocol included conventional anatomical images and DSC enhanced perfusion MR imaging. Using MGH perfusion software, parameter maps of cerebral blood flow (CBF) cerebral blood volume (CBV) and mean transit time (MTT) were created. The bilateral caudate nucleus head, globus pallidus, putamen and thalamus were selected as regions of interest (ROI) with ipsilateral white matter of the frontal lobe used as reference. Ratios (ROI versus ipsilateral white matter in frontal lobe) for CBF, CBV and MTT in the patient group were compared with those in the control group. RESULTS The CBF ratios for every ROI were higher in SHE patients versus the controls. Statistically, significant increases were detected in the left globus pallidus, putamen and thalamus (P<0.05) For MTT, the reduction in values reached statistical significance in the right head of the caudate nucleus and bilateral thalamus (P<0.05) CBV values were not significantly different compared with those of the control group (P>0.05) CONCLUSION Increased CBF and decreased MTT values in the basal ganglia and thalamus were identified in patients with SHE. The CBF increase was compatible with the idea that the CBF is redistributed from cortical areas to the basal ganglia structures.", "author_names": [ "Tao Li", "Xin Li", "Weihua Zhou", "Xiaoming Cui", "Lin Ma" ], "corpus_id": 8609225, "doc_id": "8609225", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Dynamic susceptibility contrast enhanced first pass perfusion MR imaging in patients with subclinical hepatic encephalopathy.", "venue": "Journal of neuroradiology. Journal de neuroradiologie", "year": 2012 }, { "abstract": "Abstract Purpose Despite their availability and simplicity of use, Electronic Portal Imaging Devices (EPIDs) have not yet replaced detector arrays for patient specific QA in 3D. The purpose of this study is to perform a large scale dosimetric evaluation of transit and non transit EPID dosimetry against absolute dose measurements in 3D. Methods After evaluating basic dosimetric characteristics of the EPID and two detector arrays (Octavius 1500 and Octavius 1000SRS) 3D dose distributions for 68 VMAT arcs, and 10 IMRT plans were reconstructed within the same phantom geometry using transit EPID dosimetry, non transit EPID dosimetry, and the Octavius 4D system. The reconstructed 3D dose distributions were directly compared by g analysis (2L2 2% local/2 mm and 3G2 3% global/2 mm, 50% isodose) and by the percentage difference in median dose to the high dose volume %HDVD 50) Results Regarding dose rate dependency, dose linearity, and field size dependence, the agreement between EPID dosimetry and the two detector arrays was found to be within 1.0% In the 2L2 g comparison with Octavius 4D dose distributions, the average g pass rate value was 92.2 5.2%(1SD) and 94.1 4.3%(1SD) for transit and non transit EPID dosimetry, respectively. 3G2 g pass rate values were higher than 95% in 150/156 cases. %HDVD 50 values were within 2% in 134/156 cases and within 3% in 155/156 cases. With regard to the clinical classification of alerts, 97.5% of the treatments were equally classified by EPID dosimetry and Octavius 4D. Conclusion Transit and non transit EPID dosimetry are equivalent in dosimetric terms to conventional detector arrays for patient specific QA. Non transit 3D EPID dosimetry can be readily used for pre treatment patient specific QA of IMRT and VMAT, eliminating the need of phantom positioning.", "author_names": [ "Igor Olaciregui-Ruiz", "Begona Vivas-Maiques", "Jochem Kaas", "Thijs Perik", "Frits Wittkamper", "Ben J Mijnheer", "Anton Mans" ], "corpus_id": 153312095, "doc_id": "153312095", "n_citations": 10, "n_key_citations": 1, "score": 0, "title": "Transit and non transit 3D EPID dosimetry versus detector arrays for patient specific QA", "venue": "Journal of applied clinical medical physics", "year": 2019 }, { "abstract": "It has been recently claimed that KOIs 268.01, 303.01, 1888.01, 1925.01, 2728.01 3320.01 are exomoon candidates, based on an analysis of their transit timing. Here, we perform an independent investigation, which is framed in terms of three questions: 1) Are there significant excess TTVs? 2) Is there a significant periodic TTV? 3) Is there evidence for a non zero moon mass? We applied rigorous statistical methods to these questions alongside a re analysis of the Kepler photometry and find that none of the KOIs satisfy these three tests. Specifically, KOIs 268.01 3220.01 pass none of the tests and KOIs 303.01, 1888.01 1925.01 pass a single test each. Only KOI 2728.01 satisfies two, but fails the cross validation test for predictions. Further, detailed photodynamical modeling reveals that KOI 2728.01 favours a negative radius moon (as does KOI 268.01) We also note that we find a significant photoeccentric for KOI 1925.01 indicating an eccentric orbit of e>(0.62+ 0.06) For comparison, we applied the same tests to Kepler 1625b, which reveals that 1) and 3) are passed, but 2) cannot be checked with the cross validation method used here, due to the limited number of available epochs. In conclusion, we find no compelling evidence for exomoons amongst the six KOIs. Despite this, we're able to derive exomoon mass upper limits versus semi major axis, with KOI 3220.01 leading to particularly impressive constraints of Ms/Mp 0.4% [2 sigma] at a similar relative semi major to that of the Earth Moon.", "author_names": [ "David Kipping" ], "corpus_id": 225253170, "doc_id": "225253170", "n_citations": 2, "n_key_citations": 1, "score": 0, "title": "An Independent Analysis of the Six Recently Claimed Exomoon Candidates", "venue": "", "year": 2020 }, { "abstract": "Objective:To evaluate computed tomography (CT) perfusion using first pass methods for lung nodule characterization. Methods:Fifty seven patients with 51 malignant and 6 benign nodules underwent first pass, dynamic contrast enhanced CT (50 mL, 3 5 mL/s. Kinetic analysis tools were CT Perfusion 3 (GEMS, Milwaukee, WI) a distributed parameter model approach, yielding blood volume (BV; mL/100 g) blood flow (BF; mL/min/100 g) mean transit time (1/s) and permeability surface area (mL/min/100 g) and an in house Patlak style analysis yielding fractional BV (mL/100 g) and an estimate of extraction (Kps, mL/100 g/min) Results:CT Perfusion 3 parameters in malignant and benign nodules were: mean transit time 10.1 0.9 1/s versus 11.1 3.1 1/s (ns) permeability surface 23.3 9.1 mL/min/100 g versus 19.6 10.3 mL/min/100 g (ns) BF 111.3 8.7 mL/min/100 g versus 39.1+ 5.7 mL/min/100 g (P 0.001) BV 9.3+ 0.7 mL/100 g versus 4.1 1.1 mL/100 g (P 0.002) Patlak parameters were: Kps 13.3 1.2 mL/100 g/min versus 3.9 0.8 mL/100 g/min (P 0.001) BV 8.4 0.8 mL/100 g versus 3.6 1.3 mL/100 g (P 0.01) The two kinetic methods show good agreement for BV estimation (Bland Altman plot) The limits of agreement (bias 2 standard deviation of bias) were 1.2 5.3 mL/100 g. Conclusion:CT Perfusion using first pass modeling appears feasible for lung nodule characterization. Given the short acquisition duration used, weaknesses of the modeling methods are exposed. Nonetheless, microvascular characterization in terms of BF, BV, or Kps appears useful in distinguishing malignant from benign nodules.", "author_names": [ "Igor Sitartchouk", "Heidi C Roberts", "Andre Pereira", "Hamid Bayanati", "Tom Waddell", "Timothy P L Roberts" ], "corpus_id": 22803079, "doc_id": "22803079", "n_citations": 48, "n_key_citations": 1, "score": 0, "title": "Computed Tomography Perfusion Using First Pass Methods for Lung Nodule Characterization", "venue": "Investigative radiology", "year": 2008 }, { "abstract": "OBJECTIVE To differentiate adrenal adenoma from metastasis in patients using perfusion computed tomography (PCT) imaging. METHODS Thirty two patients with adrenal masses underwent first pass PCT imaging. Of these patients, twenty one were diagnosed with adrenal adenoma, and the others with metastases. Perfusion maps of blood volume (BV) blood flow (BF) mean transit time (MTT) and permeability surface area production (PS) were generated with an Advantage Windows workstation using the CT perfusion 3.0 software (General Electric Medical Systems, Milwaukee, WI) Histopathologic sections immunostained for CD34 were quantitatively evaluated for microvessel density (MVD) RESULTS The perfusion parameters such as BV, BF and PS were statistically significant different between the two groups, with adenomas showing higher mean BV (12.18 versus 3.86) BF (97.51 versus 45.99) and PS (21.73 versus 10.93) compared with metastases (p<0.05) For BV, a cutoff point of 7.30 was found to have a sensitivity of 95.2% and a specificity of 100% to differentiate between adenoma and metastasis. The sensitivity and specificity were 81.0 and 80.0% respectively, for BF with a cutoff point of 71.96; and 85.7 and 86.7% respectively, for PS with a cutoff point of 12.70 to differentiate adenoma and metastasis. A comparison of MVD counts from adenomas with those from metastases showed a significant difference (p<0.05) However, no significant differences were observed in the four perfusion parameters and MVD between lipid rich and lipid poor adenomas. CONCLUSION PCT may be useful for evaluating the neovascularization of adrenal masses and differentiating adenoma from metastasis on the basis of PCT parameters. Adenomas show higher BV, BF and PS compared with metastases. According our data, the optimal threshold BV is 7.30, resulting in a sensitivity of 95.2% and a specificity of 100% for the differentiation of adenoma from metastasis. Adrenal adenomas have similar hemodynamic profiles, which are apparently independent of the lipid content of an adenoma.", "author_names": [ "Zhong-wei Qiao", "Chunchao Xia", "Yan-bo Zhu", "Wei-ping Shi", "Fei Miao" ], "corpus_id": 19408309, "doc_id": "19408309", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "First pass perfusion computed tomography: initial experience in differentiating adrenal adenoma from metastasis.", "venue": "European journal of radiology", "year": 2010 }, { "abstract": "BackgroundDue to the different properties of the contrast agents, the lung perfusion maps as measured by 99mTc labeled macroaggregated albumin perfusion scintigraphy (PS) are not uncommonly discrepant from those measured by dynamic contrast enhanced MRI (DCE MRI) using indicator dilution analysis in complex pulmonary circulation. Since PS offers the pre capillary perfusion of the first pass transit, we hypothesized that an inflow weighted perfusion model of DCE MRI could simulate the result by PS.Methods22 patients underwent DCE MRI at 1.5T and also PS. Relative perfusion contributed by the left lung was calculated by PS (PSL% by DCE MRI using conventional indicator dilution theory for pulmonary blood volume (PBVL% and pulmonary blood flow (PBFL% and using our proposed inflow weighted pulmonary blood volume (PBViwL% For PBViwL% the optimal upper bound of the inflow weighted integration range was determined by correlation coefficient analysis.ResultsThe time to peak of the normal lung parenchyma was the optimal upper bound in the inflow weighted perfusion model. Using PSL% as a reference, PBVL% showed error of 49.24% to 40.37% (intraclass correlation coefficient RI 0.55) and PBFL% had error of 34.87% to 27.76% (RI 0.80) With the inflow weighted model, PBViwL% had much less error of 12.28% to 11.20% (RI 0.98) from PSL%.ConclusionsThe inflow weighted DCE MRI provides relative perfusion maps similar to that by PS. The discrepancy between conventional indicator dilution and inflow weighted analysis represents a mixed flow component in which pathological flow such as shunting or collaterals might have participated.", "author_names": [ "Yi-Ru Lin", "Shang-Yueh Tsai", "Teng-Yi Huang", "Hsiao-Wen Chung", "Yi-Luan Huang", "Fu-Zong Wu", "Chu-Chuan Lin", "N J Peng", "Ming-Ting Wu" ], "corpus_id": 11766370, "doc_id": "11766370", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Inflow weighted pulmonary perfusion: comparison between dynamic contrast enhanced MRI versus perfusion scintigraphy in complex pulmonary circulation", "venue": "Journal of Cardiovascular Magnetic Resonance", "year": 2013 }, { "abstract": "ABSTRACT Bees often forage in habitats with cluttered vegetation and unpredictable winds. Navigating obstacles in wind presents a challenge that may be exacerbated by wind induced motions of vegetation. Although wind blown vegetation is common in natural habitats, we know little about how the strategies of bees for flying through clutter are affected by obstacle motion and wind. We filmed honeybees Apis mellifera flying through obstacles in a flight tunnel with still air, headwinds or tailwinds. We tested how their ground speeds and centering behavior (trajectory relative to the midline between obstacles) changed when obstacles were moving versus stationary, and how their approach strategies affected flight outcome (successful transit versus collision) We found that obstacle motion affects ground speed: bees flew slower when approaching moving versus stationary obstacles in still air but tended to fly faster when approaching moving obstacles in headwinds or tailwinds. Bees in still air reduced their chances of colliding with obstacles (whether moving or stationary) by reducing ground speed, whereas flight outcomes in wind were not associated with ground speed, but rather with improvement in centering behavior during the approach. We hypothesize that in challenging flight situations (e.g. navigating moving obstacles in wind) bees may speed up to reduce the number of wing collisions that occur if they pass too close to an obstacle. Our results show that wind and obstacle motion can interact to affect flight strategies in unexpected ways, suggesting that wind blown vegetation may have important effects on foraging behaviors and flight performance of bees in natural habitats. Summary: To approach moving obstacles, honeybees reduce speeds in still air but increase speeds in wind. To transit obstacles, bees reduce speeds in still air but alter flight paths in wind.", "author_names": [ "Nicholas P Burnett", "Marc A Badger", "Stacey A Combes" ], "corpus_id": 219948791, "doc_id": "219948791", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Wind and obstacle motion affect honeybee flight strategies in cluttered environments", "venue": "Journal of Experimental Biology", "year": 2020 } ]

[ { "abstract": "The ability to incorporate a dopant element into silicon nanocrystals (NC) and quantum dots (QD) is one of the key technical challenges for the use of these materials in a number of optoelectronic applications. Unlike doping of traditional bulk semiconductor materials, the location of the doping element can be either within the crystal lattice (c doping) on the surface (s doping) or within the surrounding matrix (m doping) A review of the various synthetic strategies for doping silicon NCs and QDs is presented, concentrating on the efficacy of the synthetic routes, both in situ and post synthesis, with regard to the structural location of the dopant and the doping level. Methods that have been applied to the characterization of doped NCs and QDs are summarized with regard to the information that is obtained, in particular to provide researchers with a guide to the suitable techniques for determining dopant concentration and location, as well as electronic and photonic effectiveness of the dopant.", "author_names": [ "Brittany L Oliva-Chatelain", "Thomas M Ticich", "Andrew R Barron" ], "corpus_id": 10446912, "doc_id": "10446912", "n_citations": 46, "n_key_citations": 1, "score": 1, "title": "Doping silicon nanocrystals and quantum dots.", "venue": "Nanoscale", "year": 2016 }, { "abstract": "Abstract As the most fundamental material for microelectronics, silicon (Si) has bourgeoned in the past more than half a century. However, given the indirect bandgap of Si, the use of Si in optoelectronics is relatively limited due to its mediocre optical absorption and rather poor optical emission. During many years of efforts for extending the use of Si in optoelectronics Si nanocrystals (NCs) that are one type of the most important Si nanostructures have attracted significant attention owing to their remarkable electronic and optical properties. Si NCs are actually crystalline Si nanoparticles, which may be called Si quantum dots if their size is smaller than ~10 nm. With the manipulation of the size, surface and doping of Si NCs great tunability for the light emission from Si NCs with the quantum yield of more than 60% has been realized. Based on the efficient light emission from Si NCs high performance Si NC light emitting devices have been demonstrated. In the meantime, the efficient light emission from Si NCs has also been utilized for synaptic simulations in neuromorphic computing and down shifting in photovoltaics. Broadband optical absorption ranging from the ultraviolet to mid infrared has been recently obtained for Si NCs mainly by taking advantage of doping. This has enabled the use of Si NCs in novel solar cells, photodetectors and optoelectronic synaptic devices. The continuous improvement of the electronic and optical properties of Si NCs has made Si NCs unfading Si materials for optoelectronics, contributing to the development of Si based optoelectronic integration.", "author_names": [ "Zhenyi Ni", "Shu Zhou", "Shuangyi Zhao", "Wenbing Peng", "Deren Yang", "Xiaodong Pi" ], "corpus_id": 199178216, "doc_id": "199178216", "n_citations": 31, "n_key_citations": 0, "score": 0, "title": "Silicon nanocrystals: unfading silicon materials for optoelectronics", "venue": "Materials Science and Engineering: R: Reports", "year": 2019 }, { "abstract": "Silicon nanocrystals, also known as silicon quantum dots, are regarded as green alternatives to traditional quantum dots composed of heavy metal elements. While it is well known that the semiconductor properties of these materials can be tuned by doping with p/n type dopants (i.e. boron and phosphorus) there is a lack of systematic understanding of their potential environmental impact if released into the ecosystem. Here, we demonstrate that introduction of dopants, especially phosphorus, cause doped silicon nanocrystals to produce reactive oxygen species, resulting in significant toxicity to a model microorganism, Shewanella oneidensis MR 1. In addition, the interaction between bacteria cells and silicon nanocrystals was investigated using dark field microscopy and bio TEM. Interestingly, boron doped silicon nanocrystals tended to attach to the cell surface while this phenomenon was not observed for undoped or phosphorus doped silicon nanocrystals.", "author_names": [ "Bo Zhi", "Sadhana Mishra", "Natalie V Hudson-Smith", "Uwe R Kortshagen", "Christy L Haynes" ], "corpus_id": 106386338, "doc_id": "106386338", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Toxicity Evaluation of Boron and Phosphorus Doped Silicon Nanocrystals toward Shewanella oneidensis MR 1", "venue": "", "year": 2018 }, { "abstract": "Doping with donor and acceptor impurities is an effective way to control light emission originated from quantum size effect in Si nanocrystals. Combined measurements of photoluminescence intensity and kinetics give valuable information on mechanisms of the doping influence. Phosphorus, boron, and nitrogen were introduced by ion implantation into Si+ implanted thermal SiO2 films either before or after synthesis of Si nanocrystals performed at Si excess of about 10 at. and annealing temperatures of 1000 and 1100 degrees C. After the implantation of the impurity ions the samples were finally annealed at 1000 degrees C. It is found that, independently of ion kind, the ion irradiation (the first stage of the doping process) completely quenches the photoluminescence related to Si nanocrystals (peak at around 750 nm) and modifies visible luminescence of oxygen deficient centers in the oxide matrix. The doping with phosphorus increases significantly intensity of the 750 nm photoluminescence excited by a pulse 337 nm laser for the annealing temperature of 1000 degrees C, while introduction of boron and nitrogen atoms reduces this emission for all the regimes used. In general, the effective lifetimes (ranging from 4 to 40 micros) of the 750 nm photoluminescence correlate with the photoluminescence intensity. Several factors such as radiation damage, influence of impurities on the nanocrystals formation, carrier impurity interaction are discussed. The photoluminescence decay is dominated by the non radiative processes due to formation or passivation of dangling bonds, whereas the intensity of photoluminescence (for excitation pulses much shorter than the photoluminescence decay) is mainly determined by the radiative lifetime. The influence of phosphorus doping on radiative recombination in Si quantum dots is analyzed theoretically.", "author_names": [ "Alexey N Mikhaylov", "David Tetelbaum", "Vladimir A Burdov", "Oleg N Gorshkov", "A I Belov", "D A Kambarov", "Vladimir Alekseevich Belyakov", "V K Vasiliev", "Anatoly Kovalev", "D M Gaponova" ], "corpus_id": 8336566, "doc_id": "8336566", "n_citations": 17, "n_key_citations": 1, "score": 0, "title": "Effect of ion doping with donor and acceptor impurities on intensity and lifetime of photoluminescence from SiO2 films with silicon quantum dots.", "venue": "Journal of nanoscience and nanotechnology", "year": 2008 }, { "abstract": "Experimental results on photoluminescence spectra and kinetics obtained in the studies of SiO2 oxide layers nanostructured by ion implantation of silicon with subsequent doping and annealing are systematized. It is shown that phosporus doping by ion implantation leads to a severalfold increase in the intensity and decay time of nonstationary photoluminescence at l 750 nm because of an increase in the probability of radiative recombination at Si doped quantum dots and of passivation of dangling bonds at the nanocrystal matrix interfaces.", "author_names": [ "A I Belov", "Vladimir Alekseevich Belyakov", "Vladimir A Burdov", "A N Mikhailov", "David Tetelbaum" ], "corpus_id": 98708730, "doc_id": "98708730", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Phosphorus doping as an efficient way to modify the radiative interband recombination in silicon nanocrystals", "venue": "", "year": 2009 }, { "abstract": "Doping of Si nanocrystals is an important topic in the emerging field of Si nanocrystals based all Si tandem solar cells. Boron doped Si nanocrystals embedded in a silicon dioxide matrix were realized by a co sputtering process, followed by high temperature annealing. The x ray photoelectron spectroscopy B 1s signal attributable to Si B (187 eV) and/or B B (188 eV) indicates that the boron may exist inside Si nanocrystals. A higher probability of effective boron doping was suggested for Si rich oxide films with a low oxygen content, Then, structural and optical properties were characterized with a focus on the effects of the boron content on Si quantum dots. The results show that as the boron content increases, the nanocrystal size is slightly reduced and the Si crystallization is suppressed. The photoluminescence intensity of the films is decreased as the boron content increases. This is due to boron induced defects and/or Auger processes induced by effective doping. These results can provide optimal conditions for future Si quantum dot based solar cells.", "author_names": [ "Xiaojing Hao", "Eun-Chel Cho", "Chris Flynn", "Y S Shen", "Gavin Conibeer", "M a Green" ], "corpus_id": 39343997, "doc_id": "39343997", "n_citations": 72, "n_key_citations": 1, "score": 0, "title": "Effects of boron doping on the structural and optical properties of silicon nanocrystals in a silicon dioxide matrix.", "venue": "Nanotechnology", "year": 2008 }, { "abstract": "Silicon nanocrystal quantum dots in a dielectric matrix form a material with higher band gap than silicon, but still compatible with silicon technology. So far, devices using silicon nanocrystals have been realized either on silicon wafers, or using in situ doping in the superlattice deposition which may hinder the nanocrystal formation. In this paper, a vertical PIN device is presented which allows to investigated the electrical and photovoltaic properties of nanocrystal quantum dot layers. The device structure circumvents any influence of a substrate wafer or dopants and provides full flexibility in the material choice of both, i.e. electron and hole, contacts. Furthermore, not high temperature stable contact materials can be applied. Devices have been realized using SiC/Si nanocrystal multilayers as the i region and doped a SixC1 x:H layers as electron and hole contacts. First devices show open circuit voltage of up to 400mV.", "author_names": [ "Philipp Loper", "A Witzky", "Andreas Hartel", "Sebastian Gutsch", "Daniel Hiller", "Jan Christoph Goldschmidt", "Stefan Janz", "Stefan W Glunz", "Margit Zacharias" ], "corpus_id": 119368453, "doc_id": "119368453", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Photovoltaic properties of silicon nanocrystals in silicon carbide", "venue": "OPTO", "year": 2012 }, { "abstract": "While the literature for the doping of silicon quantum dots (QDs) and nanocrystals (NCs) is extensive, reports of doping their germanium analogs are sparse. We report a range of attempts to dope Ge QDs both during and post synthesis. The QDs have been characterized by TEM, XPS, and I/V measurements of SiO 2 coated QD thin films in test cells using doped Si substrates. The solution synthesis of Ge QDs by the reduction of GeCl 4 with LiAlH 4 results in Ge QDs with a low level of chlorine atoms on the surface; however, during the H 2 PtCl 6 catalyzed alkylation of the surface with allylamine, to enable water solubility of the Ge QDs, chlorine functionalization of the surface occurs resulting in p type doping of the QD. A similar location of the dopant is proposed for phosphorus when incorporated by the addition of PCl 3 during QD synthesis; however, the electronic doping effect is greater. The detected dopants are all present on the surface of the QD s type) suggesting a self purification process is operative. Attempts to incorporate boron or gallium during synthesis were unsuccessful.", "author_names": [ "Brittany L Oliva-Chatelain", "Andrew R Barron" ], "corpus_id": 54619620, "doc_id": "54619620", "n_citations": 5, "n_key_citations": 1, "score": 0, "title": "Experiments towards size and dopant control of germanium quantum dots for solar applications", "venue": "", "year": 2015 }, { "abstract": "The analysis of original works devoted to preparation and investigation of nanocrystalline silicon (nc Si) films containing Si quantum dots (QDs) that exhibit photoluminescence (PL) within the range 1.4 3.2 eV at room temperature is presented. Thin films were prepared by pulse laser deposition (PLD) Offered by authors doping these nc Si films with gold in the growing process provided passivation of Si dangling bonds (DB) and some increase in the forbidden gap width of a barrier layer. Demonstrated are possibilities to explain and control stationary and kinetic characteristics of visible PL in the framework of the quantum dimensional model as well as radiative exciton annihilation with taking into account Si nanocrystals (NCs) size distribution pronounced in PL features.", "author_names": [ "E B Kaganovich", "Sergey V Svechnikov", "E G Manoilov", "I M Kizyak" ], "corpus_id": 98503385, "doc_id": "98503385", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Formation of photoluminescent properties inherent to silicon quantum dots", "venue": "", "year": 2006 }, { "abstract": "The question about the mechanisms of the photoluminescence enhancement of the system of silicon nanocrystals embedded into silica matrix at phosphorus doping is described. Both the experimental and theoretical arguments are presented.", "author_names": [ "David Tetelbaum", "Vladimir A Burdov", "Alexey N Mikhaylov", "Sergei A Trushin" ], "corpus_id": 98041047, "doc_id": "98041047", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "About the phosphorus sensitization of silicon quantum dots in SiO2 photoluminescence", "venue": "Saratov Fall Meeting", "year": 2003 } ]

[ { "abstract": "The field of terahertz integrated technology has undergone significant development in the past ten years. This has included work on different substrate technologies such as III V semiconductors and silicon, work on field effect transistor devices and heterojunction bipolar devices, and work on both fully electronic and hybrid electronic photonic systems. While approaches in electronic and photonics can often seem distinct, techniques have blended in the terahertz frequency range and many emerging systems can be classified as photonics inspired or hybrid. Here, we review the development of terahertz integrated electronic and hybrid electronic photonic systems, examining, in particular, advances that deliver important functionalities for applications in communication, sensing and imaging. Many of the advances in integrated systems have emerged, not from improvements in single devices, but rather from new architectures that are multifunctional and reconfigurable and break the trade offs of classical approaches to electronic system design. We thus focus on these approaches to capture the diversity of techniques and methodologies in the field.This Review Article examines the development of terahertz integrated electronic and hybrid electronic photonic systems, considering, in particular, advances that deliver important functionalities for applications in communication, sensing and imaging.", "author_names": [ "Kaushik Sengupta", "Tadao Nagatsuma", "Daniel M Mittleman" ], "corpus_id": 86387206, "doc_id": "86387206", "n_citations": 172, "n_key_citations": 6, "score": 1, "title": "Terahertz integrated electronic and hybrid electronic photonic systems", "venue": "", "year": 2018 }, { "abstract": "Graphene is in many respects a nanomaterial with unique properties. Here I discuss the electronic structure, transport and optical properties of graphene, and how these are utilized in exploratory electronic and optoelectronic devices. Some suggestions for needed advances are made.", "author_names": [ "Phaedon Avouris" ], "corpus_id": 5269721, "doc_id": "5269721", "n_citations": 1137, "n_key_citations": 14, "score": 0, "title": "Graphene: electronic and photonic properties and devices.", "venue": "Nano letters", "year": 2010 }, { "abstract": "This article reviews the basic theoretical aspects of graphene, a one atom thick allotrope of carbon, with unusual two dimensional Dirac like electronic excitations. The Dirac electrons can be controlled by application of external electric and magnetic fields, or by altering sample geometry and/or topology. The Dirac electrons behave in unusual ways in tunneling, confinement, and the integer quantum Hall effect. The electronic properties of graphene stacks are discussed and vary with stacking order and number of layers. Edge (surface) states in graphene depend on the edge termination (zigzag or armchair) and affect the physical properties of nanoribbons. Different types of disorder modify the Dirac equation leading to unusual spectroscopic and transport properties. The effects of electron electron and electron phonon interactions in single layer and multilayer graphene are also presented.", "author_names": [ "Antonio H Castro Neto", "Francisco Guinea", "Nuno M R Peres", "Kostya S Novoselov", "Andre K Geim" ], "corpus_id": 5650871, "doc_id": "5650871", "n_citations": 16332, "n_key_citations": 331, "score": 0, "title": "The electronic properties of graphene", "venue": "", "year": 2009 }, { "abstract": "Recent research and development has been incredibly successful at advancing the capabilities for vacuum electronic device (VED) sources of powerful terahertz (THz) and near THz coherent radiation, both CW or average and pulsed. Currently, the VED source portfolio covers over 12 orders of magnitude in power (mW to GW) and two orders of magnitude in frequency (from 0.1 to 10 THz) Further advances are still possible and anticipated. They will be enabled by improved understanding of fundamental beam wave interactions, electromagnetic mode competition and mode control, along with research and development of new materials, fabrication methods, cathodes, electron beam alignment and focusing, magnet technologies, THz metrology and advanced, broadband output radiation coupling techniques.", "author_names": [ "John H Booske", "Richard Dobbs", "Colin D Joye", "Carol Kory", "G R Broderick Neil", "Gun-Sik Park", "Jaehun Park", "Richard J Temkin" ], "corpus_id": 30141170, "doc_id": "30141170", "n_citations": 628, "n_key_citations": 12, "score": 0, "title": "Vacuum Electronic High Power Terahertz Sources", "venue": "IEEE Transactions on Terahertz Science and Technology", "year": 2011 }, { "abstract": "Semiconductor devices have become indispensable for generating electromagnetic radiation in everyday applications. Visible and infrared diode lasers are at the core of information technology, and at the other end of the spectrum, microwave and radio frequency emitters enable wireless communications. But the terahertz region (1 10 THz; 1 THz 1012 Hz) between these ranges has remained largely underdeveloped, despite the identification of various possible applications for example, chemical detection, astronomy and medical imaging. Progress in this area has been hampered by the lack of compact, low consumption, solid state terahertz sources. Here we report a monolithic terahertz injection laser that is based on interminiband transitions in the conduction band of a semiconductor (GaAs/AlGaAs) heterostructure. The prototype demonstrated emits a single mode at 4.4 THz, and already shows high output powers of more than 2 mW with low threshold current densities of about a few hundred A cm 2 up to 50 K. These results are very promising for extending the present laser concept to continuous wave and high temperature operation, which would lead to implementation in practical photonic systems.", "author_names": [ "Rudeger Kohler", "Alessandro Tredicucci", "Fabio Beltram", "Harvey E Beere", "Edmund H Linfield", "A Giles Davies", "David A Ritchie", "Rita Claudia Iotti", "Fausto Rossi" ], "corpus_id": 4422664, "doc_id": "4422664", "n_citations": 2221, "n_key_citations": 46, "score": 0, "title": "Terahertz semiconductor heterostructure laser", "venue": "Nature", "year": 2002 }, { "abstract": "Ultrathin epitaxial graphite was grown on single crystal silicon carbide by vacuum graphitization. The material can be patterned using standard nanolithography methods. The transport properties, which are closely related to those of carbon nanotubes, are dominated by the single epitaxial graphene layer at the silicon carbide interface and reveal the Dirac nature of the charge carriers. Patterned structures show quantum confinement of electrons and phase coherence lengths beyond 1 micrometer at 4 kelvin, with mobilities exceeding 2.5 square meters per volt second. All graphene electronically coherent devices and device architectures are envisaged.", "author_names": [ "Claire Berger", "Zhi-min Song", "Xuebin Li", "Xiaosong Wu", "Nate Brown", "Cecile Naud", "Didier Mayou", "Tianbo Li", "Joanna Hass", "Alexei Marchenkov", "Edward H Conrad", "Phillip N First", "Walt A de Heer" ], "corpus_id": 12039124, "doc_id": "12039124", "n_citations": 4573, "n_key_citations": 47, "score": 0, "title": "Electronic Confinement and Coherence in Patterned Epitaxial Graphene", "venue": "Science", "year": 2006 }, { "abstract": "Terahertz spectroscopy systems use far\\|infrared radiation to extract molecular spectral information in an otherwise inaccessible portion of the electromagnetic spectrum. Materials research is an essential component of modern terahertz systems; novel, higher\\|power terahertz sources rely heavily on new materials such as quantum cascade structures. At the same time, terahertz spectroscopy and imaging provide a powerful tool for the characterization of a broad range of materials, including semiconductors and biomolecules.", "author_names": [ "Zhang Xi" ], "corpus_id": 124311782, "doc_id": "124311782", "n_citations": 569, "n_key_citations": 17, "score": 0, "title": "Materials for terahertz science and technology", "venue": "", "year": 2003 }, { "abstract": "We present what is to our knowledge the first imaging system based on optoelectronic terahertz time domain spectroscopy. Terahertz time domain waveforms are downconverted from the terahertz to the kilohertz frequency range, and the waveform for each pixel is frequency analyzed in real time with a digital signal processor to extract compositional information at that point. We demonstrate applications to package inspection and chemical content mapping in biological objects.", "author_names": [ "B B Hu", "Martin C Nuss" ], "corpus_id": 11593500, "doc_id": "11593500", "n_citations": 1439, "n_key_citations": 20, "score": 0, "title": "Imaging with terahertz waves.", "venue": "Optics letters", "year": 1995 }, { "abstract": "This revised second edition on the \"Quantum Theory of the Optical and Electronic Properties of Semiconductors\" presents the basic elements needed to understand and engage in research in semiconductor physics. In this revised second edition misprints are corrected and some new and more detailed material is added. In order to treat the valence band structure of semiconductors, an introduction to the k.p. theory and the related description in terms of the Luttinger Hamiltonian is included. An introductory chapter on mesoscopic semiconductor structures discussing the modifications of the envelope function approximation caused by the spatial quantum confinement is also included. Many results are developed in parallel first for bulk material, and then for quasi two dimensional quantum wells, and for quasi one dimensional quantum wires. Semiconductor quantum dots are treated in a separate chapter. The discussion of time dependent and coherent phenomena in semiconductors has been considerably extended by including a section dealing with the theoretical description of photon echoes in semiconductors. A new chapter on magneto absorption has been added, in which magneto excitons and magneto plasmas in two dimensional systems are discussed. The chapter on electron kinetics due to the interaction with longitudinal optical phonons has been extended. The material is presented in sufficient detail for graduate students and researchers who have a general background in quantum mechanics, and is aimed at solid state physicists, engineers, materials and optical scientists.", "author_names": [ "Hartmut Haug", "Stephan W Koch" ], "corpus_id": 121331645, "doc_id": "121331645", "n_citations": 2439, "n_key_citations": 170, "score": 0, "title": "Quantum Theory of the Optical and Electronic Properties of Semiconductors", "venue": "", "year": 1990 }, { "abstract": "The richness of optical and electronic properties of graphene attracts enormous interest. Graphene has high mobility and optical transparency, in addition to flexibility, robustness and environmental stability. So far, the main focus has been on fundamental physics and electronic devices. However, we believe its true potential lies in photonics and optoelectronics, where the combination of its unique optical and electronic properties can be fully exploited, even in the absence of a bandgap, and the linear dispersion of the Dirac electrons enables ultrawideband tunability. The rise of graphene in photonics and optoelectronics is shown by several recent results, ranging from solar cells and light emitting devices to touch screens, photodetectors and ultrafast lasers. Here we review the state of the art in this emerging field.", "author_names": [ "Francesco Bonaccorso", "Z Sun", "Tawfique Hasan", "Andrea C Ferrari" ], "corpus_id": 15426689, "doc_id": "15426689", "n_citations": 5812, "n_key_citations": 70, "score": 0, "title": "Graphene photonics and optoelectronics", "venue": "", "year": 2010 } ]

[ { "abstract": "Abstract Herein, Bi2Fe4O9 nanoplates (BFO NPs) with controllable thickness are successfully synthesized via a facile hydrothermal method with varied content of sodium dodecyl benzene sulfonate (SDBS) The thickness along the [001] direction of the BFO NPs can be controlled by varying the SDBS content, and the decreased thickness plays multiple roles in improving the photocatalytic water oxidation performance: (1) increasing the distortion and asymmetries of the FeO4 tetrahedral and FeO6 octahedral units, and enhancing the built in electric field in the BFO NPs accordingly, to facilitate the efficient separation of photogenerated electron hole pairs; (2) reducing the migration distance of holes to the surface of the both oxygen and bismuth enriched {001} facets; (3) promoting the exposure of {001} facets of the BFO NPs which facilitates hole accumulation and provides more active sites to accelerate surface oxidation reaction. As a result, the as prepared BFO 2 sample with optimized thickness exhibits the best photocatalytic water oxidation performance under visible light irradiation, achieving the O2 evolution rate of 461.08 umol g 1 h 1, about 7.87 times higher than BFO NPs prepared without using SDBS. The built in electric field for BFO and its role in photocatalytic water oxidation process are reported for the first time. This work provides new insights into improving intrinsic activity of individual semiconductor photocatalyst by morphology and structure modulation and charge behavior regulation.", "author_names": [ "Huan-huan Liu", "Lipei Li", "Changfa Guo", "Jiqiang Ning", "Yijun Zhong", "Yong Hu" ], "corpus_id": 213285079, "doc_id": "213285079", "n_citations": 38, "n_key_citations": 0, "score": 0, "title": "Thickness dependent carrier separation in Bi2Fe4O9 nanoplates with enhanced photocatalytic water oxidation", "venue": "", "year": 2020 }, { "abstract": "Abstract Graphitic carbon nitride (g C3N4) with fluorine (F) doping was synthesized by a hydrothermal technique, and F doped g C3N4/Bi2Fe4O9 composites were synthesized by electrostatic self assembly technique. The crystal structures were studied by X ray diffraction, the morphology was determined by transmission electron microscope images, and the F doping was verified by energy dispersive X ray analysis, Fourier transform infrared spectroscopy, and X ray photoelectron spectroscopy. The N2 adsorption/desorption results showed that introducing Bi2Fe4O9 nanoparticles into F doped g C3N4 reduced the specific surface area and volume of the pores. This could be attributed to the Bi2Fe4O9 nanoparticles partially blocking the pores of F doped g C3N4. The photocatalytic performance of F doped g C3N4/Bi2Fe4O9 composites was studied by oxidizing NO under visible irradiation. The photocatalytic performance indicated that the presence of Bi2Fe4O9 increased the photocatalytic activity of F doped g C3N4 by up to ~100% The increased photocatalytic performance could be ascribed to a decreased combination rate of the charge carriers. Moreover, scavenger testing study showed that the reactive species, including h+ O2, and *O2 played important roles in the photocatalytic reactions.", "author_names": [ "Huazhong Liu", "Xiaolan Wang", "Han Xu", "Chunxia Luo" ], "corpus_id": 219061893, "doc_id": "219061893", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Facile synthesis of F doped g C3N4/Bi2Fe4O9 heterostructure with Z scheme for enhanced photocatalytic performance in NO oxidation", "venue": "", "year": 2020 }, { "abstract": "Pure phase Bi2Fe4O9 microstructures have been successfully synthesized via a facile hydrothermal method without using any organic surfactants. It was found that the synthesis of micro cubes and micro plates of Bi2Fe4O9 can be controlled by adjusting the NaOH concentration from 6 M to 12 M, at 200 degC for 12 h, with an optimized Bi/Fe molar ratio of 2:1. With the increase of NaOH concentration, the morphology of the products developed from micro cubes with a lateral size of 1.5 mm to micro plates with a lateral size of 1 mm and a curved outline. Moreover, the as synthesized Bi2Fe4O9 micro cubes and micro plates were evaluated for the photocatalytic degradation of methylene blue (MB) under visible light irradiation. A 90% degradation of MB with a time of 120 min has been achieved by using Bi2Fe4O9 micro plates, where the first order k constant was determined to be 0.01883 min 1. In addition, these micro plates exhibit a typical ferromagnetic property at room temperature, offering an opportunity for efficient utilization and recycling via possible magnetic assisted separation of organic pollutants for photocatalytic degradation.", "author_names": [ "Si Min Yin", "Wen Qian Li", "Runrun Cheng", "Y F Yuan", "S Y Guo", "Zhaohui Ren" ], "corpus_id": 226286424, "doc_id": "226286424", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Hydrothermal Synthesis, Photocatalytic and Magnetic Properties of Pure Phase Bi2Fe4O9 Microstructures", "venue": "Journal of Electronic Materials", "year": 2020 }, { "abstract": "A magnetic Bi2Fe4O9/Bi2MoO6 heterojunction was synthesized by a facile one pot solvothermal method, and the photodegradation performance was evaluated by degrading methylene blue (MB) and tetracycline hydrochloride (TC) Compared with pure Bi2MoO6 composite, the Bi2Fe4O9/Bi2MoO6 heterojunction with 10% Bi2Fe4O9 had much higher catalytic performance, which can degrade MB and TC completely within 150 and 180 min. The characterization results show that a p n heterojunction formed between Bi2Fe4O9 and Bi2MoO6. Combining with trapping experiments, a direct Z scheme mechanism was proposed to effectively separate photodegradable electron hole pairs at the Bi2Fe4O9/Bi2MoO6 heterojunction interface. Moreover, the obtained catalysts can be recovered easily from liquid system via the external magnet field due to the sufficient magnetism. After five recycles, no significant decrease on the degradation efficiency of MB and TC can be found show that BiFeMo 2 has excellent chemical stability in the application of organic pollutants degradation under visible light irradiation. Thus, the prepared Bi2Fe4O9/Bi2MoO6 catalyst has the advantages of high visible light catalytic activity, excellent chemical stability and magnetic separation, and has broad application prospects in environmental purification. A novel magnetic recoverable Bi2Fe4O9/Bi2MoO6 catalyst was facilely prepared. BiFeMo 2 sample showed a higher activities for MB and TC photodegradation under visible light irradiation due to formation of a p n heterojunction with high quality interface between Bi2Fe4O9 (220) and Bi2MoO6 (131) which can improve charge transfer effectively follow the Z scheme mechanism.", "author_names": [ "Huiming Zhang", "He Bian", "Haixia Zhang", "Bin Xu", "Caihong Wang", "Lijuan Zhang", "Dazhi Li", "Fengxiang Wang" ], "corpus_id": 211266262, "doc_id": "211266262", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Magnetic Separable Bi2Fe4O9/Bi2MoO6 Heterojunctions in Z Scheme with Enhanced Visible Light Photocatalytic Activity for Organic Pollutant Degradation", "venue": "Catalysis Letters", "year": 2020 }, { "abstract": "An efficient binary Bi2Fe4O9/Bi2WO6 Z scheme heterojunction was fabricated through a facile hydrothermal route. The obtained Bi2Fe4O9/Bi2WO6 displays high catalytic activity for rhodamine B (RhB) photodegradation, and 100% of RhB was photodegraded by Bi2Fe4O9 (7%/Bi2WO6 within 90 min, which is much better than that by pure Bi2Fe4O9 and Bi2WO6. The effective photoinduced carrier separation, the broadened photoabsorption range, high oxidation capacity of hole, and the high reduction power of electron are in charge of the elevated catalytic activity because of the formed Z scheme system. In addition, the effects such as pollutant concentration, pH, inorganic anions, and water sources exerted on photocatalytic performance were also investigated, and the results suggest that Bi2Fe4O9/Bi2WO6 still possesses a high photocatalytic performance. The free radical trapping experiments and electron spin resonance spin trapping technology disclose that hole (h+ hydroxy radical *OH) and superoxide radical *O2 are cardinal active radicals in the catalytic system. In terms of the above experimental analysis, a possible photodegradation mechanism of the as fabricated photocatalyst is thoroughly elucidated. In addition, the possible RhB photodegradation pathway is also raised in the light of the analysis of liquid chromatography mass/mass spectrometry. In addition, Bi2Fe4O9/Bi2WO6 composite does not display dramatic reduction of the catalytic performance after five recycles. Thus, this study reveals that the as obtained Bi2Fe4O9/Bi2WO6 catalyst has a great prospect for the environmental purification.", "author_names": [ "Bisheng Li", "Cui Lai", "Guangming Zeng", "Lei Qin", "Huan Yi", "Danlian Huang", "Chengyun Zhou", "Xigui Liu", "Min Cheng", "Piao Xu", "Chen Zhang", "Fanglong Huang", "Shiyu Liu" ], "corpus_id": 206485667, "doc_id": "206485667", "n_citations": 234, "n_key_citations": 0, "score": 0, "title": "Facile Hydrothermal Synthesis of Z Scheme Bi2Fe4O9/Bi2WO6 Heterojunction Photocatalyst with Enhanced Visible Light Photocatalytic Activity.", "venue": "ACS applied materials interfaces", "year": 2018 }, { "abstract": "Pure Bi25FeO40, Bi2Fe4O9, and different weight ratios of Bi25FeO40/Bi2Fe4O9 composite photocatalysts have been synthesized via a hydrothermal process combined with a mixing calcination method and evaluated as visible light responsive catalyst for the degradation of Rhodamine B (RhB) All the as prepared samples have been characterized by a range of techniques including X ray diffraction (XRD) Fourier transform infrared spectra (FT IR) UV vis absorption spectra (DSR) Field Emission Scanning Electron Microscope (FE SEM) Transmission electron microscope (TEM) and High resolution TEM (HRTEM) The XRD, FT IR, TEM and HRTEM results confirm that the composite only consists of Bi25FeO40 and Bi2Fe4O9. In the Bi25FeO40/Bi2Fe4O9 composites, closely contacted interfaces have been observed. Compared with the single phase Bi25FeO40 and Bi2Fe4O9, Bi25FeO40/Bi2Fe4O9 composites exhibit enhanced visible light responsive photocatalytic activities. The photocatalytic efficiency of optimized Bi25FeO40/Bi2Fe4O9 composite with Bi2Fe4O9 weight ratio of 30% is about 8.8 and 6.2 times higher than that of pure Bi25FeO40 and Bi2Fe4O9, respectively. On the basis of electronic energy band structure analysis, the active species trapping experiments and the electrochemical impedance spectrum (EIS) performance, a heterojunction type charge transfer mechanism interpreting the enhanced photocatalytic activities of the composite are proposed and discussed. In addition, the effects of different Bi25FeO40/Bi2Fe4O9 weight ratios and their geometry architecture on photocatalytic activities are also thoroughly discussed.", "author_names": [ "Geming Wang", "Da Cheng", "Tiancheng He", "Yiyu Hu", "Quanrong Deng", "Yangwu Mao", "Shenggao Wang" ], "corpus_id": 155950305, "doc_id": "155950305", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Enhanced visible light responsive photocatalytic activity of Bi25FeO40/Bi2Fe4O9 composites and mechanism investigation", "venue": "Journal of Materials Science: Materials in Electronics", "year": 2019 }, { "abstract": "Polycrystalline Bi2Fe4O9 nanoparticles were successfully prepared by a hydrothermal assisted sol gel method. X ray diffraction (XRD) data, Fourier transform infrared (FTIR) spectra, and Raman spectra reveal that Bi2Fe4O9 nanoparticles has orthorhombic mullite structure without other impurities such as Bi2O3, Fe3O4, BiFeO3, Fe2O3. Scanning electron microscopy (SEM) shows that the synthesized polycrystalline Bi2Fe4O9 particles have regular spherical shape and the average particle size of 50 nm. Optical properties of the Bi2Fe4O9 nanoparticles were studied by UV Vis absorption spectroscopy, and the bandgap energy (Eg) value is found to be 1.75 eV. Magnetic characterization shows that the Bi2Fe4O9 nanoparticles exhibit a paramagnetic behavior at 300 K and undergo an antiferromagnetic transition at 190 K. Ferroelectric hysteresis loops with rounded corners at room temperature at 50 Hz are observed for the Bi2Fe4O9 nanoparticles due to the large electrical leakage. Photocatalytic experiments indicate that the Bi2Fe4O9 nanoparticles exhibit excellent photocatalytic activity and stability in degradation of methylene blue (MB) and methyl red (MR) dyes under visible light irradiation.", "author_names": [ "Fu Ma", "Hongjian Zhao" ], "corpus_id": 202745448, "doc_id": "202745448", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Optical, Magnetic, Ferroelectric Properties and Photocatalytic Activity of Bi2Fe4O9 Nanoparticles through a Hydrothermal Assisted Sol Gel Method", "venue": "Russian Journal of Physical Chemistry A", "year": 2019 }, { "abstract": "Polycrystalline Bi2Fe4O9 nanoparticles were successfully prepared by a hydrothermal assisted sol gel method. X ray diffraction (XRD) data, Fourier transform infrared (FTIR) spectra, and Raman spectra reveal that Bi2Fe4O9 nanoparticles has orthorhombic mullite structure without other impurities such as Bi2O3, Fe3O4, BiFeO3, Fe2O3. Scanning electron microscopy (SEM) shows that the synthesized polycrystalline Bi2Fe4O9 particles have regular spherical shape and the average particle size of 50 nm. Optical properties of the Bi2Fe4O9 nanoparticles were studied by UV Vis absorption spectroscopy, and the bandgap energy (Eg) value is found to be 1.75 eV. Magnetic characterization shows that the Bi2Fe4O9 nanoparticles exhibit a paramagnetic behavior at 300 K and undergo an antiferromagnetic transition at 190 K. Ferroelectric hysteresis loops with rounded corners at room temperature at 50 Hz are observed for the Bi2Fe4O9 nanoparticles due to the large electrical leakage. Photocatalytic experiments indicate that the Bi2Fe4O9 nanoparticles exhibit excellent photocatalytic activity and stability in degradation of methylene blue (MB) and methyl red (MR) dyes under visible light irradiation.", "author_names": [ "" ], "corpus_id": 202749262, "doc_id": "202749262", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Optical, Magnetic, Ferroelectric Properties and Photocatalytic Activity of Bi2Fe4O9 Nanoparticles through a Hydrothermal Assisted Sol Gel Method", "venue": "Russian Journal of Physical Chemistry A", "year": 2019 }, { "abstract": "In this work, ternary all solid state Z scheme g C3N4/carbon nanotubes/Bi2Fe4O9 (g C3N4/CNT/BFO) composites with enhanced photocatalytic activity were prepared by a hydrothermal method. The morphology observation shows that ternary heterojunctions are formed in the g C3N4/CNT/BFO composites. The photocatalytic activity of the samples for the degradation of acid orange 7 was investigated under simulated sunlight irradiation. It was found that the ternary composites exhibit remarkable enhanced photocatalytic activity when compared with bare BFO and g C3N4/BFO composites. The effect of the CNT content on the photocatalytic performance of the ternary composites was investigated. The photocatalytic mechanism of g C3N4/CNT/BFO was proposed according to the photoelectrochemical measurement, photoluminescence, active species trapping experiment and energy band potential analysis. The results reveal that the introduction of CNT as an excellent solid electron mediator into the ternary composites can effectively accelerate the electron migration between BFO and g C3N4. This charge transfer process results in highly efficient separation of photogenerated charges, thus leading to greatly enhanced photocatalytic activity of g C3N4/CNT/BFO composites. Furthermore, the g C3N4/CNT/BFO composites also exhibit highly efficient photo Fenton like catalysis property.", "author_names": [ "Lijing Di", "Hua Yang", "Tao Xian", "Xiujuan Chen" ], "corpus_id": 53712541, "doc_id": "53712541", "n_citations": 53, "n_key_citations": 0, "score": 0, "title": "Construction of Z Scheme g C3N4/CNT/Bi2Fe4O9 Composites with Improved Simulated Sunlight Photocatalytic Activity for the Dye Degradation", "venue": "Micromachines", "year": 2018 }, { "abstract": "Abstract A series of Bi 2 Fe 4 O 9 /g C 3 N 4 composite photocatalysts are prepared via a facile mixing calcination method. The crystal structures of composites are investigated by X ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT IR) The Field Emission Scanning Electron Microscope (FE SEM) in combination with Energy Dispersive X ray Spectroscopy (EDS) mapping analysis and Transmission Electron Microcopy (TEM) images illustrate the uniform distribution of constituent elements and clear interface between Bi 2 Fe 4 O 9 and g C 3 N 4 component. The visible light driven photocatalytic rates of Rhodamine B over Bi 2 Fe 4 O 9 /g C 3 N 4 composites increase and then decrease with the increase of g C 3 N 4 content. The effects of Bi 2 Fe 4 O 9 /g C 3 N 4 weight ratios on photocatalytic performance are thoroughly discussed. Meanwhile, the active species trapping experiments and the electrochemical impedance spectra as well as the electronic energy band structure estimation analysis demonstrate that the photocatalytic mechanism for Bi 2 Fe 4 O 9 /g C 3 N 4 composites is ascribed to the Z scheme. In addition, the recyclability and stability experiments of the composite are also studied.", "author_names": [ "Geming Wang", "Shutong Liu", "Tiancheng He", "Xuan Liu", "Quanrong Deng", "Yangwu Mao", "Shenggao Wang" ], "corpus_id": 104163068, "doc_id": "104163068", "n_citations": 26, "n_key_citations": 1, "score": 0, "title": "Enhanced visible light driven photocatalytic activities of Bi2Fe4O9/g C3N4 composite photocatalysts", "venue": "", "year": 2018 } ]

[ { "abstract": "A low voltage low power CMOS reference current source is designed by biasing MOSFETs in the sub threshold region. This current source operates with the battery of 0.8V produces stable reference current of 20nA. The circuit has been designed using 180nm CMOS technology of Semiconductor Laboratory of ISRO India simulated using \"Analog design Environment\" of Cadence. This reference current source provides a current sensitivity of 0.65 percent per volt with power supply voltage, a variation in reference current is just 0.001 percent with a variation of the load from 1 ohm to 1 Mega Ohm, temperature sensitivity of reference current is 0.032 percent per deg C consumes just 232nW. This reference current source is quite suitable for biomedical applications implantable devices where low voltage and low power stable reference current source is the primary requirement.", "author_names": [ "Chetali Yadav", "Sunita Prasad" ], "corpus_id": 46829316, "doc_id": "46829316", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "20nA sub threshold biased CMOS reference current source", "venue": "2017 International Conference on Information, Communication, Instrumentation and Control (ICICIC)", "year": 2017 }, { "abstract": "This paper presents the design and application of a CMOS sub 1V voltage reference using a 2 transistor Self Cascode MOSFET (SCM) structure able to get low power consumption, temperature compensation, and small area. An efficient design procedure applied to this simple topology relying on NMOS transistors with different threshold voltages allows attaining large immunity against bias current and supply voltage variations. The two transistors can operate in weak, moderate, or strong inversion making the design flexible in terms of area and power consumption. Implemented in a 0.18mm standard CMOS technology, the circuit provides a 400mV voltage reference with a variation of 0.18% from 20degC to 75degC (or less than 15ppm/degC) operates from 3.6V down to 800mV while biased with a 5nA resistor less PTAT current source that varies 30% over PVT, and consumes less than 20nA with an area of 0.01mm2. The same concept was used to create a temperature compensated voltage drop with regard to a monitored power supply voltage but using a 2 PMOS SCM structure with transistors of different threshold voltages. These two circuits were adopted as part of a Power Management (PM) system for RFID tag applications. The PM includes a LDO voltage regulator and a low voltage detector that require both the voltage reference and the low voltage monitor. The LDO regulated output voltage and the trip point of the voltage detector vary 5.5% and 3.3% respectively, over temperature, without trimming.", "author_names": [ "Alfredo Olmos", "Fabricio Jorge Antunes Ferreira", "Fernando da Rocha Paixao Cortes", "Fernando Chavez" ], "corpus_id": 40242234, "doc_id": "40242234", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A 2 Transistor Sub 1 V Low Power Temperature Compensated CMOS Voltage Reference Design and Application", "venue": "", "year": 2015 }, { "abstract": "This paper presents the design of a CMOS sub 1V voltage reference using a 2 transistor Self Cascode MOSFET structure able to get low power consumption, temperature compensation, and small area. An efficient design procedure applied to this simple topology relying on NMOS transistors with different threshold voltages allows attaining large immunity against bias current and supply voltage variations. Besides that, the two transistors can operate in weak, moderate, or strong inversion making the design flexible in terms of area and power consumption. Implemented in a 0.18 mm standard CMOS technology, the circuit provides a 400mV voltage reference with a variation of 0.18% from 20degC to 75degC (or less than 15ppm/degC) operates from 3.6V down to 800mV while biased with a 5nA resistor less PTAT current source that varies 30% over PVT, and consumes less than 20nA. The complete circuit including the current source and the 2 transistor Self Cascode MOSFET occupies an area of 0.01mm2.", "author_names": [ "Alfredo Olmos", "Juan Pablo Martinez Brito", "Fabricio Jorge Antunes Ferreira", "Fernando Chavez", "Marcelo Lubaszewski" ], "corpus_id": 3806, "doc_id": "3806", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "A 2 transistor sub 1V low power temperature compensated CMOS voltage reference", "venue": "2014 27th Symposium on Integrated Circuits and Systems Design (SBCCI)", "year": 2014 }, { "abstract": "Because of the universal adoption of global biasing technique for IC design,the stability of biased circuit has important influence on the performance of the whole circuit.One kind of bias current reference based on VT and working in its subthreshold domain,which is able to meet the requirement of less working current and low power consumption is analyzed in this paper.At the same time,the bias current reference is extremely unsensitive to current change.The output current shifts within 9%0 while the power voltage changes from 0.7 V to 5 V.The entire circuit is simulated with Cadence Spectre,and the result shows low power consumption and high PSRR.", "author_names": [ "Chang Chang-yuan" ], "corpus_id": 112139731, "doc_id": "112139731", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design and Analysis of a Sub threshold Operation CMOS Reference Current Source", "venue": "", "year": 2007 }, { "abstract": "A nano watt bandgap voltage reference (BGR) is presented. To provide a low voltage and low power BGR, the circuit has been biased in the sub threshold region; thereby, drawing a few nano amperes current from the source, has been achieved. In order to reduce die area and also power consumption, instead of resistor, transistor is used. To generate PTAT voltage, self cascode composite structure is used for the transistors. The results from post layout simulation using 0.18 mm standard CMOS technology show that the proposed BGR circuit generates a reference voltage of 625 mV, obtaining temperature coefficient of 13 ppm/ degC in the temperature range of 25 degC to 110 degC. The simulated power supply rejection ratio is 42 dB. Fully designed with MOS transistors, the circuit draws 18 nA from a 0.9 V supply. The active area of the proposed BGR is 0.00067 mm 2", "author_names": [ "Iman Fakharyan", "Mehdi Ehsanian", "Hadi Hayati" ], "corpus_id": 201905495, "doc_id": "201905495", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "A 0.9 V supply, 16.2 nW, fully MOSFET resistorless bandgap reference using sub threshold operation", "venue": "Analog Integrated Circuits and Signal Processing", "year": 2019 }, { "abstract": "This paper presents an original low voltage CMOS, bipolar transistor free, sub threshold voltage reference capable of operating with sub 1V supply voltages. Novel aspects of the proposed solution are (i) use of a bandgap core with a single MOSFET to avoid threshold voltage error terms and (ii) adoption of an high gain, low offset inverter like amplifier in the bandgap feedback loop. Relatively high output current sourcing capabilities are obtained by means of an output source follower stage based on native MOSFETs. The circuit potentiality is demonstrated by means of electrical simulations performed on a prototype designed with a standard 0.18um CMOS process. A reference voltage of 0.483 V, with a maximum variation of 4mV in a temperature range of 20/80degC, has been obtained with a supply voltage of 0.7 V. The maximum output current is 200mA with a quiescient current consumpion of only 9.8mA.", "author_names": [ "Andrea Ria", "Alessandro Catania", "Mattia Cicalini", "Lorenzo Benvenuti", "Massimo Piotto", "Paolo Bruschi" ], "corpus_id": 199490255, "doc_id": "199490255", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A Sub 1V CMOS Switched Capacitor Voltage Reference with high output current capability", "venue": "2019 15th Conference on Ph.D Research in Microelectronics and Electronics (PRIME)", "year": 2019 }, { "abstract": "This paper proposes a low voltage CMOS Nano power current reference circuit and presents its performance with circuit simulation in 180nm UMC CMOS technology. The proposed circuit consists of start up, Bias voltage, currentsource sub circuits with most of the MOSFETs operating in sub threshold region. Simulation results shows that the circuit generates a stable reference current of 4 nA in supply voltage range 1 V1.8 V with line sensitivity of .The temperature coefficient of the current was at 1.8 V in the range of The power dissipation was 380 NW at 1.8 V Supply. The proposed circuit would be suitable for use in sub threshold operated power aware large scale integration.", "author_names": [ "Dinesh Kushwaha", "D K Mishra" ], "corpus_id": 6272971, "doc_id": "6272971", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Nano Power Current Reference Circuit consisting of Sub threshold CMOS Circuits", "venue": "", "year": 2017 }, { "abstract": "In this work a new topology for a self biased current reference, based on an asymmetric bulk modified MOS (ABM) composite transistor is presented. Two current references based in this technique were designed: a 13.5nA current reference in a $1.5\\mu \\mathrm{m} CMOS technology, and a 100nA current reference in a $0.18\\mu \\mathrm{m} CMOS technology. The latter was designed to minimize the temperature dependence of the output current; the result was less than 5% from 0degC to 100degC, which is a very good result in comparison to other reported similar current references.", "author_names": [ "Diego Costa", "Matias R Miguez", "Joel Gak", "Fabian Torres", "Alfredo Arnaud" ], "corpus_id": 214691671, "doc_id": "214691671", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Self biased Current Source, using an Asymmetric Bulk modified MOS Composite Transistor", "venue": "2020 Argentine Conference on Electronics (CAE)", "year": 2020 }, { "abstract": "Abstract The sub threshold circuit design is regarded as a promising technique to provide considerable power reduction for ultra low power applications under tight energy constraints. This paper presents Power Gating Sub Threshold Source Coupled Logic (PG STSCL) which employs the fine grain power gating at the gate level. It introduces isolation and retention circuits to ensure reliable propagation of data along a pipeline of power gated circuits, called a micro pipeline. While the conventional STSCL circuits can considerably cut down the active power consumption, they have the drawback of continuous static current flow. To overcome this drawback, the proposed architecture shuts off the static current by utilizing the fine grain power gating technique. We have designed a 32 bit adder based on the proposed PG STSCL gates in a 65 nm CMOS technology. The adder was simulated and compared to reference adders using standard CMOS gates, and conventional STSCL gates. Simulations demonstrated that the proposed gates provide a power reduction of 89.56% and 99.78% when compared to the standard CMOS and STSCL gates, respectively.", "author_names": [ "Hossam Hassan", "Sameh A Ibrahim", "Hyungwon Kim" ], "corpus_id": 4632948, "doc_id": "4632948", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Power Gating Sub Threshold Source Coupled Logic (PG STSCL) circuits for ultra low power applications", "venue": "Microelectron. J.", "year": 2018 }, { "abstract": "The invention belongs to the technical field of simulation integrated circuits, and discloses a low power consumption sub threshold type CMOS band gap reference voltage circuit. The circuit comprises a start circuit, a reference current source generation circuit, a voltage division circuit and a reference voltage output circuit. The start circuit is used for enabling a reference voltage source to get rid of a zero degeneracy point and to work under specific work voltage. The reference current source generation circuit is used for generating current to provide bias for a rear end circuit, and MOS transistors in the rear end circuit all work in a sub threshold region. The voltage division circuit is used for enabling an output circuit to reach required technical indexes and generating a negative temperature coefficient. The reference voltage output circuit is used for generating voltage with a positive temperature coefficient and making the output voltage Vref have the zero temperature characteristic. The low power consumption sub threshold type CMOS band gap reference voltage circuit has the advantages of being low in work voltage, low in power consumption and low in temperature coefficient.", "author_names": [ "" ], "corpus_id": 115931754, "doc_id": "115931754", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Low power consumption sub threshold type CMOS band gap reference voltage circuit", "venue": "", "year": 2015 } ]

[ { "abstract": "Metal halide perovskite semiconductors possess excellent optoelectronic properties, allowing them to reach high solar cell performances. They have tunable bandgaps and can be rapidly and cheaply deposited from low cost precursors, making them ideal candidate materials for tandem solar cells, either by using perovskites as the wide bandgap top cell paired with low bandgap silicon or copper indium diselenide bottom cells or by using both wide and small bandgap perovskite semiconductors to make all perovskite tandem solar cells. This Review highlights the unique potential of perovskite tandem solar cells to reach solar to electricity conversion efficiencies far above those of single junction solar cells at low costs. We discuss the recent developments in perovskite based tandem fabrication, and detail directions for future research to take this technology beyond the proof of concept stage.Perovskites, with their wide bandgap range, are good partners for both commercial and novel photovoltaic technologies in multijunction solar cells. Here, McGehee and co workers review recent material and device developments and highlight future challenges and opportunities for perovskite based tandems.", "author_names": [ "T Leijtens", "Kevin A Bush", "Rohit Prasanna", "Michael D McGehee" ], "corpus_id": 139426002, "doc_id": "139426002", "n_citations": 299, "n_key_citations": 0, "score": 1, "title": "Opportunities and challenges for tandem solar cells using metal halide perovskite semiconductors", "venue": "", "year": 2018 }, { "abstract": "Summary Organic inorganic halide perovskites are promising semiconductors to mate with silicon in tandem photovoltaic cells due to their solution processability and tunable complementary bandgaps. Herein, we show that a combination of two additives, MACl and MAH2PO2, in the perovskite precursor can significantly improve the grain morphology of wide bandgap (1.64 1.70 eV) perovskite films, resulting in solar cells with increased photocurrent while reducing the open circuit voltage deficit to 0.49 0.51 V. The addition of MACl enlarges the grain size, while MAH2PO2 reduces non radiative recombination through passivation of the perovskite grain boundaries, with good synergy of functions from MACl and MAH2PO2. Matching the photocurrent between the two sub cells in a perovskite/silicon monolithic tandem solar cell by using a bandgap of 1.64 eV for the top cell results in a high tandem Voc of 1.80 V and improved power conversion efficiency of 25.4%", "author_names": [ "Bo Chen", "Zhengshan J Yu", "Kong Liu", "Xiaopeng Zheng", "Ye Liu", "Jianwei Shi", "Derrek Spronk", "Peter N Rudd", "Zachary C Holman", "Jinsong Huang" ], "corpus_id": 106297141, "doc_id": "106297141", "n_citations": 155, "n_key_citations": 0, "score": 0, "title": "Grain Engineering for Perovskite/Silicon Monolithic Tandem Solar Cells with Efficiency of 25.4%", "venue": "", "year": 2019 }, { "abstract": "Abstract Multi junction tandem design has been proven to be an effective means to further improve the efficiency of solar cells. However, its share in the photovoltaics market at present is tiny, since the most efficient tandem device comprises III V semiconductors, which entail the use of expensive fabrication processes. The advent of perovskite solar cells, which have revitalized the PV field with their unprecedented pace of development, promises to address this bottleneck. Perovskite materials could not only serve as the top subcell absorber for commercial solar cells including Si and copper indium gallium selenide, but could work efficiently as bottom subcells owing to highly tuneable bandgaps which extend down to the range of ~1.2 to 1.5 eV. The highest efficiency perovskite tandem to date was achieved by pairing a perovskite top cell with a Si bottom cell in a four terminal configuration, yielding 26.4% This review gives an overview of recent progress on the main tandem structures, and describes the detailed design improvements that have resulted in new record efficiencies. Ultimately, commercialization of these tandem solar cells relies on the scalability of perovskite technology. We, therefore, highlight the development of large scale tandems and approaches to produce perovskite modules. We also point out the critical aspects that will require further effort and provide guidelines for future developments. The potential obstacles that will hamper the commercialization of perovskite tandems, if not adequately addressed, namely device stability and toxicity, are then critically examined. Finally, the substantial opportunities that perovskite materials open up for other solar devices with a tandem configuration are mentioned, which are attracting increasing attention.", "author_names": [ "Heping Shen", "The Duong", "Yiliang Wu", "Jun Peng", "Daniel A Jacobs", "Nandi Wu", "Klaus J Weber", "Thomas P White", "Kylie R Catchpole" ], "corpus_id": 139975138, "doc_id": "139975138", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Metal halide perovskite: a game changer for photovoltaics and solar devices via a tandem design", "venue": "", "year": 2018 }, { "abstract": "The past decade has witnessed the growing interest in metal halide perovskites as driven by their promising applications in diverse fields. The low intrinsic stability of the early developed organic versions has however hampered their widespread applications. Very recently, all inorganic perovskite nanocrystals have emerged as a new class of materials that hold great promise for the practical applications in solar cells, photodetectors, light emitting diodes, and lasers, among others. In this Outlook, we first discuss the recent developments in the preparation, properties, and applications of all inorganic metal halide perovskite nanocrystals, with a particular focus on CsPbX3, and then provide our view of current challenges and future directions in this emerging area. Our goal is to introduce the current status of this type of new materials to researchers from different areas and motivate them to explore all the potentials.", "author_names": [ "Qiao Zhang", "Yadong Yin" ], "corpus_id": 49567985, "doc_id": "49567985", "n_citations": 163, "n_key_citations": 2, "score": 0, "title": "All Inorganic Metal Halide Perovskite Nanocrystals: Opportunities and Challenges", "venue": "ACS central science", "year": 2018 }, { "abstract": "Metal halide perovskites have recently emerged as promising photovoltaic materials for application in solar cells with high power conversion efficiencies exceeding 23 In the years since such high efficiencies have been attained, investigations have mainly focused on the state of the art 3 D Pb based halide perovskite materials. However, the high toxicity of Pb and intrinsic instability of the pristine perovskite materials have become great obstacles to their industrial application and commercialization. To address these serious issues, it is imperative to explore low toxicity metal halide perovskites or their derivatives to substitute Pb based materials for better future development. Currently, Bi based halide perovskite like materials are attracting increased interest as environmentally friendly alternatives for photovoltaic applications. This Concept highlights recent advances of Bi based halide perovskite like materials in terms of understanding and modifying their fundamental properties and related device performance, with a focus on current challenges, opportunities for future development, and diversification of device applications.", "author_names": [ "Long-Jiang Zhang", "Kai Wang", "Bo Zou" ], "corpus_id": 59338706, "doc_id": "59338706", "n_citations": 36, "n_key_citations": 0, "score": 0, "title": "Bismuth Halide Perovskite Like Materials: Current Opportunities and Challenges.", "venue": "ChemSusChem", "year": 2019 }, { "abstract": "Metal halide perovskites have recently attracted enormous attention for photovoltaic applications due to their superior optical and electrical properties. Lead (Pb) halide perovskites stand out among this material series, with a power conversion efficiency (PCE) over 25% According to the Shockley Queisser (SQ) limit, lead halide perovskites typically exhibit bandgaps that are not within the optimal range for single junction solar cells. Partial or complete replacement of lead with tin (Sn) is gaining increasing research interest, due to the promise of further narrowing the bandgaps. This enables ideal solar utilization for single junction solar cells as well as the construction of all perovskite tandem solar cells. In addition, the usage of Sn provides a path to the fabrication of lead free or Pb reduced perovskite solar cells (PSCs) Recent progress in addressing the challenges of fabricating efficient Sn halide and mixed lead tin (Pb Sn) halide PSCs is summarized herein. Mixed Pb Sn halide perovskites hold promise not only for higher efficiency and more stable single junction solar cells but also for efficient all perovskite monolithic tandem solar cells.", "author_names": [ "Shuai Gu", "Renxing Lin", "Qiaolei Han", "Yuan Gao", "Hairen Tan", "Jia Zhu" ], "corpus_id": 211099814, "doc_id": "211099814", "n_citations": 49, "n_key_citations": 1, "score": 0, "title": "Tin and Mixed Lead Tin Halide Perovskite Solar Cells: Progress and their Application in Tandem Solar Cells.", "venue": "Advanced materials", "year": 2020 }, { "abstract": "Abstract In several photovoltaic (PV) technologies, the presence of electronic defects within the semiconductor band gap limit the efficiency, reproducibility, as well as lifetime. Metal halide perovskites (MHPs) have drawn great attention because of their excellent photovoltaic properties that can be achieved even without a very strict film growth control processing. Much has been done theoretically in describing the different point defects in MHPs. Herein, we discuss the experimental challenges in thoroughly characterizing the defects in MHPs such as, experimental assignment of the type of defects, defects densities, and the energy positions within the band gap induced by these defects. The second topic of this Review is passivation strategies. Based on a literature survey, the different types of defects that are important to consider and need to be minimized are examined. A complete fundamental understanding of defect nature in MHPs is needed to further improve their optoelectronic functionalities.", "author_names": [ "Luis K Ono", "Shengzhong Frank Liu", "Yabing Qi" ], "corpus_id": 199055804, "doc_id": "199055804", "n_citations": 85, "n_key_citations": 0, "score": 0, "title": "Reducing Detrimental Defects for High Performance Metal Halide Perovskite Solar Cells", "venue": "Angewandte Chemie", "year": 2019 }, { "abstract": "The electronic and material properties of graphene have been explored in a number of electronic and optoelectronic devices including organic and metal halide perovskite solar cells have been explored. At present, graphene based technology is considered to have many potential applications. Moreover, graphene related materials offer graphene like characteristics and the tunability of chemical, electrical and physical properties through doping and functionalization. Metal halide perovskite solar cells form the most advanced photovoltaic technology, showing an exponential increase in their certified power conversion efficiency. The most pronounced challenge is the stability of these devices, which has limited their practical applications and commercialization. The synergy between the properties of metal halide perovskite semiconductors and GRMs has recently been revealed and has contributed towards the realization of highly efficient perovskite solar cells with impressive operational stability. In this work, we review the progress made in the specific field of graphene based metal halide perovskite solar cells since 2013. The impact of exploitation of graphene and GRMs on this photovoltaic technology is multi fold, since it has resulted in the development of high quality perovskite crystals for the fabrication of more stable and flexible devices exhibiting high performance.", "author_names": [ "Costantinos Petridis", "George Kakavelakis", "Emmanuel Kymakis" ], "corpus_id": 103591918, "doc_id": "103591918", "n_citations": 39, "n_key_citations": 0, "score": 0, "title": "Renaissance of graphene related materials in photovoltaics due to the emergence of metal halide perovskite solar cells", "venue": "", "year": 2018 }, { "abstract": "DOI: 10.1002/aenm.201803135 For a two terminal monolithic tandem solar cell, the open circuit voltage (VOC) is the sum of the VOCs of the wide bandgap and low bandgap subcells while the shortcircuit current density (JSC) is limited by the lower JSC of the subcells. Therefore, achieving high VOCs for both subcells while maintaining a sufficiently high JSC for current matching is critical for realizing high efficiency two terminal tandem solar cells. For all perovskite tandem solar cells, the commonly used wide bandgap (wide Eg) subcell (1.7 1.9 eV) is based on FA1 xCsxPb(I1 yBry)3 perovskite absorbers (0 x, y 1) (FA formamidinium, Cs cesium, I iodide, Br bromide) whereas the low bandgap (low Eg) (1.1 1.3 eV) subcell is based on tin (Sn) lead (Pb) halide perovskite absorbers.[12 15] While wide Eg PSCs have achieved remarkable improvement in performance via composition tuning/engineering, annealing engineering, and interface engineering,[16 19] the performances of low Eg PSCs reported in the literature are still not satisfactory. Significant efforts have been made to improve the performance of low Eg PSCs.[6,11,20 27] Kanatzidis and coworkers have first reported the bowing effect in mixed Sn Pb perovskites, revealing the opportunity of bandgap tuning via compositional engineering.[20] McGehee and co workers have studied the effect of lattice contraction and octahedral tilting on bandgap tuning in low Eg mixed Sn Pb perovskites.[21] Hayase and co workers have introduced an n type \"spike structure\" interface to improve the charge flow at the interface of the absorber and electron transport layer (ETL)[28] Our group has boosted the efficiency to a certified value of 17% for relatively thick low Eg (1.25 eV) PSCs, beneficial for all perovskite tandem solar cells.[6,23,24,29] Recently, Jen and coworkers have incorporated 20% Br into low Eg MASn0.5Pb0.5I3 (MA methylammonium) perovskite to obtain an optimal bandgap (1.35 eV) for single junction PSC applications, and a VOC of 0.9 V was obtained.[26] However, the relatively large Eg limits its potential for applications as the low Eg bottom subcells for tandem devices.[13] So far, many reported lowEg mixed Sn Pb PSCs show relatively large VOC deficits (Eg/q VOC, where q is the unit charge) and/or low fill factors The unsatisfactory performance of low bandgap mixed tin (Sn) lead (Pb) halide perovskite subcells has been one of the major obstacles hindering the progress of the power conversion efficiencies (PCEs) of all perovskite tandem solar cells. By analyzing dark current density and distribution, it is identified that charge recombination at grain boundaries is a key factor limiting the performance of low bandgap mixed Sn Pb halide perovskite subcells. It is further found that bromine (Br) incorporation can effectively passivate grain boundaries and lower the dark current density by two three orders of magnitude. By optimizing the Br concentration, low bandgap (1.272 eV) mixed Sn Pb halide perovskite solar cells are fabricated with open circuit voltage deficits as low as 0.384 V and fill factors as high as 75% The bestperforming device demonstrates a PCE of >19% The results suggest an important direction for improving the performance of low bandgap mixed Sn Pb halide perovskite solar cells.", "author_names": [ "Chongwen Li", "Zhaoning Song", "Dewei Zhao", "Chuanxiao Xiao", "Biwas Subedi", "Niraj Shrestha", "Maxwell M Junda", "Changlei Wang", "Chunsheng Jiang", "Mowafak M Al-Jassim", "Randy J Ellingson", "Nikolas J Podraza", "Kai Zhu", "Yanfa Yan" ], "corpus_id": 104388121, "doc_id": "104388121", "n_citations": 118, "n_key_citations": 0, "score": 0, "title": "Reducing Saturation Current Density to Realize High Efficiency Low Bandgap Mixed Tin Lead Halide Perovskite Solar Cells", "venue": "", "year": 2019 }, { "abstract": "Today's photovoltaics market is dominated by single junction solar cells with a crystalline silicon (c Si) absorber. Higher efficiencies can be achieved in tandem junction devices, with a thin top cell converting the high energy part of the solar spectrum in a wide bandgap absorber, and a bottom c Si cell converting the low energy part of the spectrum [1] Alternatively, lower manufacturing costs can be achieved for polycrystalline solar cells based on direct bandgap absorbers such as Cu(In,Ga)Se2. In both cases, the research focus lies on the development of cost effective, high efficiency thin film (TF) solar cells with polycrystalline absorbers, including CdTe, Cu(In,Ga)Se2, III/V semiconductors and metal halide perovskites such as the archetypical methyl ammonium lead iodide (MAPI)", "author_names": [ "Michael E Stuckelberger", "Tara Nietzold", "Bradley M West", "Trumann Walker", "Christina Ossig", "Maik Kahnt", "Felix Wittwer", "Jixia Deng", "Jorg M Maser", "B Lai", "Zhonghou Cai", "Volker Rose", "Andrew Ulvestad", "Martin V Holt", "Stephan O Hruszkewycz", "James J Dynes", "Justin Wang", "Damien Salomon", "Remi Tucoulou", "X Huang", "H Yan", "Evgeny Nazaretski", "Yong S Chu", "Christian G Schroer", "Mariana I Bertoni" ], "corpus_id": 52042873, "doc_id": "52042873", "n_citations": 5, "n_key_citations": 1, "score": 0, "title": "Challenges and Opportunities with Highly Brilliant X ray Sources for multi Modal in Situ and Operando Characterization of Solar Cells", "venue": "Microscopy and Microanalysis", "year": 2018 } ]

[ { "abstract": "Nonmagnetic Rashba systems with broken inversion symmetry are expected to exhibit nonreciprocal charge transport, a new paradigm of unidirectional magnetoresistance in the absence of ferromagnetic layer. So far, most work on nonreciprocal transport has been solely limited to cryogenic temperatures, which is a major obstacle for exploiting the room temperature two terminal devices based on such a nonreciprocal response. Here, we report a nonreciprocal charge transport behavior up to room temperature in semiconductor a GeTe with coexisting the surface and bulk Rashba states. The combination of the band structure measurements and theoretical calculations strongly suggest that the nonreciprocal response is ascribed to the giant bulk Rashba spin splitting rather than the surface Rashba states. Remarkably, we find that the magnitude of the nonreciprocal response shows an unexpected non monotonical dependence on temperature. The extended theoretical model based on the second order spin orbit coupled magnetotransport enables us to establish the correlation between the nonlinear magnetoresistance and the spin textures in the Rashba system. Our findings offer significant fundamental insight into the physics underlying the nonreciprocity and may pave a route for future rectification devices. Most work on nonreciprocal transport is limited to cryogenic temperatures due to the low Rashba spin splitting energy. Here, the authors report a nonreciprocal charge transport behavior up to room temperature in semiconductor a GeTe with coexisting the surface and bulk Rashba states.", "author_names": [ "Yunguo Li", "Yang Li", "Peng Li", "Bin Fang", "Xu Yang", "Yan Wen", "Dongxing Zheng", "Chenhui Zhang", "Xin He", "Aurelien Manchon", "Zhaohua Cheng", "Xi-xiang Zhang" ], "corpus_id": 231687325, "doc_id": "231687325", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Nonreciprocal charge transport up to room temperature in bulk Rashba semiconductor a GeTe", "venue": "Nature communications", "year": 2021 }, { "abstract": "Nonreciprocal charge transport phenomena are studied theoretically for two dimensional noncentrosymmetric superconductors under an external magnetic field $B$ Rashba superconductors, surface superconductivity on the surface of three dimensional topological insulators, and transition metal dichalcogenides such as \\mathrm{MoS}}_{2} are representative systems, and the current voltage $I\\ensuremath{ }V$ characteristics, i.e. $V=V(I) for each of them is analyzed. $V(I) can be expanded with respect to the current $I$ as $V(I)\\ensuremath{\\sum}}_{j=1,\\ensuremath{\\infty}{a}_{j}(B,T){I}{j} and the (B,T) dependence of {a}_{j} depends on the mechanism of the charge transport. Our analysis is based on the time dependent Ginzburg Landau theory, which contains up to third order terms in the momentum of the order parameter. Above the mean field superconducting transition temperature {T}_{0} the fluctuation of the superconducting order parameter gives the additional conductivity, i.e. paraconductivity. With the extension of paraconductivity to the nonlinear response, we obtain the nonreciprocal charge transport. On the other hand, below {T}_{0} the vortices determine the Kosterlitz Thouless transition and also the resistivity. The nonreciprocal resistivity is analyzed from the dynamics of vortices in this temperature region. Based on these results, we propose the experiments to identify the mechanism of the nonreciprocal transport with the realistic estimates for the order of magnitude of the coefficients {a}_{j}(B,T) for each case.", "author_names": [ "Shintaro Hoshino", "Ryohei Wakatsuki", "Keita Hamamoto", "Naoto Nagaosa" ], "corpus_id": 119441333, "doc_id": "119441333", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Nonreciprocal charge transport in two dimensional noncentrosymmetric superconductors", "venue": "", "year": 2018 }, { "abstract": "The proximity of a transition metal dichalcogenide (TMD) to graphene imprints a rich spin texture in graphene and complements its high quality charge/spin transport by inducing spin orbit coupling (SOC) Rashba and valley Zeeman SOCs are the origin of charge to spin conversion mechanisms such as the Rashba Edelstein effect (REE) and spin Hall effect (SHE) In this work, we experimentally demonstrate for the first time charge to spin conversion due to the REE in a monolayer WS2 graphene van der Waals heterostructure. We measure the current induced spin polarization up to room temperature and control it by a gate electric field. Our observation of the REE and the inverse of the effect (IREE) is accompanied by the SHE, which we discriminate by symmetry resolved spin precession under oblique magnetic fields. These measurements also allow for the quantification of the efficiencies of charge to spin conversion by each of the two effects. These findings are a clear indication of induced Rashba and valley Zeeman SOC in graphene that lead to the generation of spin accumulation and spin current without using ferromagnetic electrodes. These realizations have considerable significance for spintronic applications, providing accessible routes toward all electrical spin generation and manipulation in two dimensional materials.", "author_names": [ "Talieh S Ghiasi", "Alexey A Kaverzin", "Patrick J Blah", "Bart van Wees" ], "corpus_id": 146120557, "doc_id": "146120557", "n_citations": 60, "n_key_citations": 0, "score": 0, "title": "Charge to Spin Conversion by the Rashba Edelstein Effect in Two Dimensional van der Waals Heterostructures up to Room Temperature", "venue": "Nano letters", "year": 2019 }, { "abstract": "Abstract The quantum interference effect in the charge transport through single phenyl molecules received intensive interests from theory but remained as an experimental challenge. In this paper, we investigated the charge transport through single molecule benzene dithiol (BDT) junction with different connectivities using mechanically controllable break junction (MCBJ) technique. By further improving the mechanical stability and the electronic measuring component of the MCBJ set up, we obtained the conductance histograms of BDT molecules (BDTs) from the statistical analysis of conductance distance traces without data selection. By tuning the connectivity, the conductance of BDTs is determined to be 10 1.2 G0, 10 2.2 G0 and 10 1.0 G0 for para, meta, and ortho connectivity, following the trend that ortho BDT para BDT meta BDT. Furthermore, the displacements of the junctions followed the trend that para meta ortho, suggesting the charge transport through the molecules via the gold thiol bond. The different trends between conductance and displacement for different connectivities suggests the presence of destructive quantum interference effect on meta BDT, which provides the experimental evidence for the quantum interference effect through single phenyl molecular junctions.", "author_names": [ "Guogang Yang", "Hao Wu", "Junying Wei", "Jueting Zheng", "Zhao-Bin Chen", "Junyang Liu", "Jia Shi", "Yang Yang", "Wenjing Hong" ], "corpus_id": 104264220, "doc_id": "104264220", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Quantum interference effect in the charge transport through single molecule benzene dithiol junction at room temperature: An experimental investigation", "venue": "", "year": 2018 }, { "abstract": "The proximity of a transition metal dichalcogenide (TMD) to graphene imprints a rich spin texture in graphene and complements its high quality charge/spin transport by inducing spin orbit coupling (SOC) Rashba and valley Zeeman SOCs are the origin of charge to spin conversion mechanisms such as Rashba Edelstein effect (REE) and spin Hall effect (SHE) In this work, we experimentally demonstrate for the first time charge to spin conversion due to the REE in a monolayer WS2 graphene van der Waals heterostructure. We measure the current induced spin polarization up to room temperature and control it by a gate electric field. Our observation of the REE and inverse of the effect (IREE) is accompanied by the SHE which we discriminate by symmetry resolved spin precession under oblique magnetic fields. These measurements also allow for quantification of the efficiencies of charge to spin conversion by each of the two effects. These findings are a clear indication of induced Rashba and valley Zeeman SOC in graphene that lead to generation of spin accumulation and spin current without using ferromagnetic electrodes. These realizations have considerable significance for spintronic applications, providing accessible routes towards all electrical spin generation and manipulation in two dimensional materials.", "author_names": [ "Talieh S Ghiasi", "Alexey A Kaverzin", "Patrick J Blah", "Bart Jan van Wees" ], "corpus_id": 203034150, "doc_id": "203034150", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Charge to Spin Conversion by the Rashba Edelstein Effect in 2D van der Waals Heterostructures up to Room Temperature", "venue": "", "year": 2019 }, { "abstract": "Understanding charge transport in DNA molecules is a long standing problem of fundamental importance across disciplines 1 2 It is also of great technological interest due to DNA's ability to form versatile and complex programmable structures. Charge transport in DNA based junctions has been reported using a wide variety of set ups 2 4 but experiments so far have yielded seemingly contradictory results that range from insulating 5 8 or semiconducting 9 10 to metallic like behaviour 11 As a result, the intrinsic charge transport mechanism in molecular junction set ups is not well understood, which is mainly due to the lack of techniques to form reproducible and stable contacts with individual long DNA molecules. Here we report charge transport measurements through single 30 nm long double stranded DNA (dsDNA) molecules with an experimental set up that enables us to address individual molecules repeatedly and to measure the current voltage characteristics from 5 K up to room temperature. Strikingly, we observed very high currents of tens of nanoamperes, which flowed through both homogeneous and non homogeneous base pair sequences. The currents are fairly temperature independent in the range 5 60 K and show a power law decrease with temperature above 60 K, which is reminiscent of charge transport in organic crystals. Moreover, we show that the presence of even a single discontinuity 'nick' in both strands that compose the dsDNA leads to complete suppression of the current, which suggests that the backbones mediate the long distance conduction in dsDNA, contrary to the common wisdom in DNA electronics 2 4 Measurements of electrical conductance in double stranded DNA suggest that the backbones mediate the long distance conduction in dsDNA, contrary to the common wisdom in DNA electronics.", "author_names": [ "Roman Zhuravel", "Haichao Huang", "Georgia Polycarpou", "Savvas Polydorides", "Phani Motamarri", "Liat Katrivas", "Dvir Rotem", "Joseph Sperling", "Linda A Zotti", "Alexander Kotlyar", "Juan Carlos Cuevas", "Vikram Gavini", "Spiros S Skourtis", "Danny Porath" ], "corpus_id": 221146905, "doc_id": "221146905", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Backbone charge transport in double stranded DNA", "venue": "Nature Nanotechnology", "year": 2020 }, { "abstract": "Hybrid nanocomposites (HNCs) of polypyrrole (PPy) and CuS were synthesized by an in situ chemical polymerization method. The HNCs were prepared by varying the CuS nanoparticles weight percentage (10 40% in PPy matrix. The XRD and FESEM characterization indicated the uniform distribution of CuS nanoparticles in PPy matrix. The XRD pattern revealed the presence of hexagonal CuS peaks overlapped with amorphous PPy pattern. Williamson Hall method was employed to estimate intrinsic strain in HNCs. FTIR spectrum revealed the shifting of 1025 cm 1 peak toward higher wavenumber, indicating insertion of CuS nanoparticles in PPy. The room temperature electrical conductivity of PPy is found to be increased from 1.15 x 10 1 to 3.70 S/cm as the content of CuS nanoparticles increases up to 40 wt% in HNCs. To explore the charge transport mechanism in HNCs,the conductivity was measured in the temperature range of 300 15 K. The measured conductivity data was analyzed with the help of Arrhenius model and 3d Mott's variable range hopping (VRH) model in the temperature range of 35 300 K. The approximate values of Mott's parameters at 300 K such as the density of states at Fermi level, average hopping distance and average hopping energy of HNCs were estimated as 4x10 24 cm 3 eV 1 1.7 A and 10 meV respectively.", "author_names": [ "Narinder Singh", "Manish Taunk" ], "corpus_id": 221673790, "doc_id": "221673790", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "In Situ Chemical Synthesis, Microstructural, Morphological and Charge Transport Studies of Polypyrrole CuS Hybrid Nanocomposites", "venue": "Journal of Inorganic and Organometallic Polymers and Materials", "year": 2020 }, { "abstract": "Poly(3,4 ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is an important opto electronic material, and its room temperature electrical conductivity can be prominently enhanced by chemical treatment; it is technologically significant to investigate its temperature and magnetic field dependent charge transport characteristics. Here, we analyzed the low temperature charge transport properties of pristine and acid treated PEDOT:PSS thin films by studying the variation in resistance as a function of temperature and magnetic field (T 300 to 4.2 K, H up to 5 T) The acid treated sample exhibited much improved charge transport behavior at low T, with a resistivity ratio [r(4.2 K)/r(300 K) of ~5.7 x 102, which is three orders of magnitude smaller than that of the pristine sample. Nevertheless, both pristine and acid treated samples followed hopping conduction, obeying R T exp T 1 2 and R T exp T 1 3, respectively, in the low T regime. Furthermore, positive magnetoresistance of ~16% (at 4.2 K and 5 T) was displayed by acid treated samples that could be due to the wave function shrinkage phenomenon.", "author_names": [ "Meenu Sharma", "Krishna Prasad Maity", "Sonam Rani", "V D Prasad", "I Sameera", "Ravi Bhatia" ], "corpus_id": 228942435, "doc_id": "228942435", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Temperature dependent charge transport of acid treated poly(3,4 ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin films", "venue": "", "year": 2020 }, { "abstract": "Abstract Sb2S3 thin film solar cells have recently gained attention due to their low cost, low toxicity, and simple fabrication. However, there is still plenty of room to improve their performance. It is known that efficient carrier transport is essential for high performance Sb2S3 solar cells, which, unfortunately, is difficult to characterize by conventional testing methods. Therefore, the carrier transport process in Sb2S3 solar cells was studied here using a theoretical simulation. The results show that high solar performances can be achieved with a wide parameter window for selecting the electron transport layer as well as the hole transport layer, viz. with a conduction band minimum of the electron transport layer 4.4 eV VBM 6.4 eV) Here the interfacial potential barrier become negligible and as a consequence electrons and holes cross at ease, which guarantee the good device performance. Indeed, a Sb2S3 solar cell with a high power conversion efficiency (PCE) can be obtained by ensuring that the carrier transport and collection are unimpeded in the device, i.e. the Sb2S3 based single junction solar cells shows high efficiency of 19.53% Furthermore, we found that optimized Sb2S3 solar cells are particularly suitable for use as the top cell of tandem structure solar cells. Thus, a Sb2S3/Sb2Se3 double junction solar cell structure was proposed. With a 0.5 mm thick Sb2S3 absorber, double junction solar cells could achieve a theoretical efficiency as high as 26.64% Our results based on the rotational design of bandgap alignment provide a general guide rule for selecting the optimal electron transport layer as well as the hole transport layer to boost the power conversion efficiency for Sb2S3 solar cells up to its theoretical limit.", "author_names": [ "Yu Cao", "Xinyun Zhu", "Jiahao Jiang", "Chaoying Liu", "Jing Zhou", "Jian Ni", "Jianjun Zhang", "Jinbo Pang" ], "corpus_id": 209712253, "doc_id": "209712253", "n_citations": 42, "n_key_citations": 0, "score": 0, "title": "Rotational design of charge carrier transport layers for optimal antimony trisulfide solar cells and its integration in tandem devices", "venue": "", "year": 2020 }, { "abstract": "Fullerene based materials are widely used as acceptor and electron transport layer materials in organic and planar perovskite solar cells. Modeling of electronic properties such as band alignment and charge transport for these applications is typically done using optimized geometries. Here, we estimate the effects of nuclear motions on band structure and electron and hole transport in two prototypical fullerenes, C60 and C70. We model the dynamics in solid fullerenes using Density Functional Tight Binding and we use the Density Functional Theory based Projection of Monomer Orbitals on Dimer Orbitals (DIPRO) approach to estimate effects on charge transfer integral in the Marcus approximation. We show that room temperature molecular dynamics cause a shift and spread of frontier orbital energies on the order of 0.1 eV which leads to an increase by more than a factor of two in the Marcus exponent, and can cause a decrease by up to orders of magnitude in the overlap integral, leading in most cases to an overall decrease in the charge transport rate.", "author_names": [ "Saeid Arabnejad", "Amrita Pal", "Koichi Yamashita", "Sergei Manzhos" ], "corpus_id": 59307764, "doc_id": "59307764", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Effect of Nuclear Motion on Charge Transport in Fullerenes: A Combined Density Functional Tight Binding Density Functional Theory Investigation", "venue": "Front. Energy Res.", "year": 2019 } ]

[ { "abstract": "1. Electromagnetic Theory 2. The Propagation of Rays and Beams 3. Propagation of Optical Beams in Fibers 4. Optical Resonators 5. Interaction of Radiation and Atomic Systems 6. Theory of Laser Oscillation and its Control in the Continuous and Pulsed Regimes 7. Some Specific Laser Systems 8. Second Harmonic Generation and Parametric oscillation 9. Electronic Modulation of Laser Beams 10. Noise in Optical Detection and Generation 11. Detection of Optical Radiation 12. Interaction of Light and Sound 13. Propagation of Coupling Modes in Optical Dielectric Waveguides Periodic Waveguides 14. Holography and Optical Data Storage 15. Semiconductor Lasers Theory and Applications 16. Advanced Semiconductor Lasers: Quantum Well Lasers, Distributed Feedback Lasers, Vertical Cavity Surface Emitting Lasers 17. Phase Conjugate Optics Theory and Applications 18. Two Beam Coupling and Phase Conjugation in Photorefractive Media 19. Optical Solitons 20. A Classical Treatment of Quantum Optics Appendices A. The Kramers Kroning relations B. The Electrooptic Effect in Cubic 43m Crystals C. Noise in Traveling Wave Lasers Amplifiers D. Transformation of a coherent", "author_names": [ "Amnon Yariv" ], "corpus_id": 117741762, "doc_id": "117741762", "n_citations": 1037, "n_key_citations": 67, "score": 1, "title": "Optical electronics in modern communications", "venue": "", "year": 1997 }, { "abstract": "Thank you for reading optical electronics in modern communications. As you may know, people have look hundreds times for their favorite novels like this optical electronics in modern communications, but end up in malicious downloads. Rather than reading a good book with a cup of coffee in the afternoon, instead they cope with some harmful virus inside their desktop computer. optical electronics in modern communications is available in our book collection an online access to it is set as public so you can get it instantly. Our books collection hosts in multiple locations, allowing you to get the most less latency time to download any of our books like this one. Merely said, the optical electronics in modern communications is universally compatible with any devices to read.", "author_names": [ "Birgit Wirtz" ], "corpus_id": 63776510, "doc_id": "63776510", "n_citations": 52, "n_key_citations": 2, "score": 0, "title": "Optical Electronics In Modern Communications", "venue": "", "year": 2016 }, { "abstract": "1. Electromagnetic Fields and Waves 2. Rays and Optical Beams 3. Dielectric Waveguides and Optical Fibers 4. Optical Resonators 5. Interaction of Radiation and Atomic Systems 6. Theory of Laser Oscillation and Some Specific Laser Systems 7. Chromatic Dispersion and Polarization Mode Dispersion in Fibers 8. Nonlinear Optics 9. Electro Optics and AO modulators 10. Noise in Optical Detection and Generation 11. Detection of Optical Radiation 12. Periodic Structures 13. Waveguide Coupling 14. Nonlinear Optical Effects in Fibers 15. Semiconductor Lasers 16. Advanced Semiconductor Lasers 17. Optical Amplifiers 18. Classical Treatment of Quantum Optics, Quantum Noise, and Squeezing A. WAVE EQUATION IN CYLINDRICAL COORDINATES AND BESSEL FUNCTIONS B. EXACT SOLUTIONS OF THE STEP INDEX CIRCULAR WAVEGUIDE C. KRAMERS KRONIG RELATIONS D. TRANSFORMATION OF A COHERENT ELECTROMAGNETIC FIELD BY A THIN LENS E. FERMI LEVEL AND ITS TEMPERATURE DEPENDENCE F. ELECTRO OPTIC EFFECT IN CUBIC 43M CRYSTALS G. CONVERSION FOR POWER UNITS AND ATTENUATION UNITS", "author_names": [ "Amnon Yariv", "Pochi Albert Yeh" ], "corpus_id": 107100857, "doc_id": "107100857", "n_citations": 906, "n_key_citations": 70, "score": 0, "title": "Photonics optical electronics in modern communications", "venue": "", "year": 2006 }, { "abstract": "Thank you for reading Photonics Optical Electronics In Modern Communications The Oxford Series In Electrical And Computer Engineering. Maybe you have knowledge that, people have look hundreds times for their chosen readings like this Photonics Optical Electronics In Modern Communications The Oxford Series In Electrical And Computer Engineering, but end up in harmful downloads. Rather than reading a good book with a cup of coffee in the afternoon, instead they juggled with some malicious bugs inside their computer.", "author_names": [ "Amnon Yariv", "Pochi Albert Yeh" ], "corpus_id": 108537744, "doc_id": "108537744", "n_citations": 210, "n_key_citations": 12, "score": 0, "title": "Photonics: Optical Electronics in Modern Communications (The Oxford Series in Electrical and Computer Engineering)", "venue": "", "year": 1997 }, { "abstract": "", "author_names": [ "Amnon Yariv" ], "corpus_id": 30949075, "doc_id": "30949075", "n_citations": 15, "n_key_citations": 3, "score": 0, "title": "Optical Electronics in Modern Communications Fifth Edition", "venue": "", "year": 2012 }, { "abstract": "Photonics, Plasmonics and Information OpticsInformation PhotonicsIntroduction to Information OpticsNeuromorphic PhotonicsMonolithic Nanoscale Photonics Electronics Integration in Silicon and Other Group IV ElementsOptical Fiber Communication Systems with MATLAB and Simulink ModelsCambridge Illustrated Handbook of Optoelectronics and PhotonicsAdvanced Digital Optical Communications, Second EditionPhotonic DevicesPhotonics and Fiber OpticsSilicon Photonics for Telecommunications and BiomedicineRF Photonic Technology in Optical Fiber LinksPhotonics, 6/EdHigh Speed and Lower Power TechnologiesPhotonics and Fiber OpticsWearable Electronics and PhotonicsSilicon PhotonicsLaser Diodes and Their Applications to Communications and Information ProcessingSilicon PhotonicsUndersea Fiber Communication SystemsPhotonicsOptical Fiber CommunicationsNoises in Optical Communications and Photonic SystemsSolutions Manual for Optical Electronics in Modern CommunicationsIntroduction to Fiber Optic CommunicationsInstructor's Solutions Manual for Photonics: Optical Electronics in Modern Communications, Sixth EditionAdvanced Optical Communication Systems and NetworksOptical Fiber Telecommunications VIIRaman Amplification in Fiber Optical Communication SystemsGraphene Photonics, Optoelectronics, and PlasmonicsOptical Fiber Communications SystemsQuantum ElectronicsApplied PhotonicsAn Introduction to Theory and Applications of Quantum MechanicsAdvances in Optical CommunicationOptics and PhotonicsNanoscale Photonics and OptoelectronicsNonlinear PhotonicsPhotonics and Electronics with GermaniumSilicon Photonics", "author_names": [], "corpus_id": 235272744, "doc_id": "235272744", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Photonics Optical Electronics Communications", "venue": "", "year": 2021 }, { "abstract": "Lightwave communications is a necessity for the information age. Optical links provide enormous bandwidth, and the optical fiber is the only medium that can meet the modern society's needs for transporting massive amounts of data over long distances. Applications range from global high capacity networks, which constitute the backbone of the internet, to the massively parallel interconnects that provide data connectivity inside datacenters and supercomputers. Optical communications is a diverse and rapidly changing field, where experts in photonics, communications, electronics, and signal processing work side by side to meet the ever increasing demands for higher capacity, lower cost, and lower energy consumption, while adapting the system design to novel services and technologies. Due to the interdisciplinary nature of this rich research field, Journal of Optics has invited 16 researchers, each a world leading expert in their respective subfields, to contribute a section to this invited review article, summarizing their views on state of the art and future developments in optical communications.", "author_names": [ "Erik Agrell", "Magnus Karlsson", "Andrew R Chraplyvy", "David John Richardson", "Peter M Krummrich", "Peter J Winzer", "Kim Roberts", "Johannes Karl Fischer", "Seb J Savory", "Benjamin J Eggleton", "Marco Secondini", "Frank R Kschischang", "Andrew Lord", "Josep Prat", "Ioannis Tomkos", "John E Bowers", "Sudharsanan Srinivasan", "Maite Brandt-Pearce", "Nicolas Gisin" ], "corpus_id": 45739081, "doc_id": "45739081", "n_citations": 328, "n_key_citations": 22, "score": 0, "title": "Roadmap on Optical Communications", "venue": "", "year": 2016 }, { "abstract": "Using plasmonics, photonics, and electronics, a nonvolatile memory cell operated both electrically and optically is demonstrated. Modern day computers rely on electrical signaling for the processing and storage of data, which is bandwidth limited and power hungry. This fact has long been realized in the communications field, where optical signaling is the norm. However, exploiting optical signaling in computing will require new on chip devices that work seamlessly in both electrical and optical domains, without the need for repeated electrical to optical conversion. Phase change devices can, in principle, provide such dual electrical optical operation, but assimilating both functionalities into a single device has so far proved elusive owing to conflicting requirements of size limited electrical switching and diffraction limited optical response. Here, we combine plasmonics, photonics, and electronics to deliver an integrated phase change memory cell that can be electrically or optically switched between binary or multilevel states. Crucially, this device can also be simultaneously read out both optically and electrically, offering a new strategy for merging computing and communications technologies.", "author_names": [ "Nikolaos Farmakidis", "Nathan Youngblood", "Xuan Li", "James Tan", "Jacob L Swett", "Zengguang Cheng", "C David Wright", "Wolfram H P Pernice", "Harish Bhaskaran" ], "corpus_id": 54075436, "doc_id": "54075436", "n_citations": 50, "n_key_citations": 1, "score": 0, "title": "Plasmonic nanogap enhanced phase change devices with dual electrical optical functionality", "venue": "Science Advances", "year": 2019 }, { "abstract": "POLAR CODES FOR OPTICAL COMMUNICATIONS Tufail Ahmad M.S. in Electrical and Electronics Engineering Advisor: Erdal Arikan May 2016 Optical communication systems have become the backbone of long distance communication networks due to their ability to transport data at high rates. A typical modern optical communication system should be capable to achieve data rates of 100 Gb/s or beyond. At such a high data rate, it is not feasible to retransmit the corrupted data. For reliable communication at improved power efficiency, communication systems use forward error correction (FEC) schemes. FEC schemes should have low latency to provide high throughput and good error performance to achieve an output bit error rate (BER) of 10 15 or lower in optical channels. Moreover, implementation schemes of these FEC codes should be simple, as telecommunications equipments in optical access networks can only accommodate restricted hardware complexity. In this contribution, we study existing ITU T G.975.1 recommended FEC schemes and recently proposed state of the art FEC codes for optical networks. Next, we analyze polar codes, a recently proposed class of error correcting codes with advantageous properties in terms of error performance, structure, latency and design method. Throughout our analysis we assume that optical channels can be modeled as additive white Gaussian noise (AWGN) channels. We investigate whether polar codes can compete with the above mentioned FEC schemes in the arena of optical communications. We conclude that polar codes outdo all G.975.1 recommended FEC codes in terms of error performance with the same overhead and relatively shorter block lengths. We also highlight some of the issues/aspects which need to be addressed to enhance the error performance of polar codes at finite block lengths so that they can catch up with (or surpass) recently proposed third generation FEC codes. Most of the proposed FEC codes for next generation optical networks are based on LDPC and turbo codes. Unfortunately, these codes have error floors at very iii", "author_names": [ "Tufail Ahmad" ], "corpus_id": 116423770, "doc_id": "116423770", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Polar codes for optical communications", "venue": "", "year": 2016 }, { "abstract": "Abstract Optical communications is the linchpin of modern communications delivering vast majority of the online traffic worldwide at the terabit per second rate. However, an exponential growth of this traffic requires proper increase in transmission rate, which, in turn, puts more pressure on finding new technological solutions to meet these demands. A possible direction of this search is application of plasmonics. Plasmonics has the potential to combine the best properties of both electronic and photonic worlds leading to the development of new units of optical systems in nanoscale footprints. Application of plasmonics in optical communications would lead to integration of plasmonic circuitry with digital electronics, which in turn would open new opportunities in research applications and lay the foundation for the next generation digital technology. This paper is the attempt to make one more step in this direction. Specifically, we propose the structure for plasmonic field modulation and demodulation under two conditions: (1) The work is done for narrow band coupling conditions and (2) graphene is used as an intermediate layer between the conductor and the cover to increase the coupling efficiency at the 1550 nm wavelength. The results include a unique description of the plasmonic coupling and resonance peak for the proposed structure and analysis of the enhancement in modulation performance caused by the insertion of the graphene layer in the plasmonic structure. The possible applications of the proposed structure are also considered.", "author_names": [ "Vitaly Sukharenko", "Roger Dorsinville", "Djafar K Mynbaev" ], "corpus_id": 104440738, "doc_id": "104440738", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Plasmonic modulation and demodulation structure for the future optical WDM devices in communication system", "venue": "Solid State Electronics", "year": 2019 } ]

[ { "abstract": "Diffraction limited 1.4 W pulsed output power is demonstrated from a two dimensional 144 element surface emitting laser array placed in an external Talbot cavity. Phase locking of the array is achieved with a parallel phase sensing and control system based on phase contrast imaging used in combination with a liquid crystal array in the laser cavity. Diffraction limited cw operation is also demonstrated.", "author_names": [ "Steve Sanders", "Robert G Waarts", "Derek W Nam", "David Welch", "Donald R Scifres", "John C Ehlert", "W J Cassarly", "J Michael Finlan", "Kevin M Flood" ], "corpus_id": 122123979, "doc_id": "122123979", "n_citations": 22, "n_key_citations": 0, "score": 2, "title": "High power coherent two dimensional semiconductor laser array", "venue": "", "year": 1994 }, { "abstract": "The design, fabrication, and testing of a two dimensional array of 900 laser diode power amplifiers injected by a single semiconductor master oscillator is discussed. This array extends the results of the 200 emitter array reported on last year. The array consists of a stack of ten 100 emitter linear arrays. Nine of the 100 emitter arrays were successfully stacked and injected by a semiconductor master oscillator laser by way of a 1 to 10 semiconductor ridge waveguide splitter and amplifier array. The tenth 100 emitter array was included in the stack but the fiber optic used to connect it to the 1 to 10 splitter broke before final strain relief was added. The 900 amplifiers produced approximately 36 W of coherent power in the near field. Poor fill optics allowed only 15.6 W to be delivered to the far field of which 5.5 W were phase aligned into a narrow beam in one axis and into 5 major spots in the other axis. Improved optics and higher power emitters are the next steps in moving this array architecture to high power and brightness.", "author_names": [ "Joseph L Levy", "Kun Roh" ], "corpus_id": 109269669, "doc_id": "109269669", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Coherent array of 900 semiconductor laser amplifiers", "venue": "Photonics West", "year": 1995 }, { "abstract": "Abstract Some of the most significant and challenging goals in the advancement of surface emitting semiconductor lasers include realizing high brightness sources. A promising method for increasing the optical power is to combine or optical couple the light output of multiple lasers into a single coherent beam. There have been a variety of methods used to achieve optical coupling in two dimensional vertical cavity surface emitting lasers (VCSELs) which include injection locking, evanescent coupling, diffractive coupling, and anti guiding or leaky mode laser coupling. This chapter will focus on the physical principles of these different coupling mechanisms and how they are incorporated into two dimensional VCSEL arrays. First, a review of beam combining methods and the metrics used to quantify their performance is presented. The advantages of coherent beam combining over incoherent beam combining is shown as well as the necessity of optical coupling for establishing coherence across a laser array. The general discussion of the optical coupling physics for each method will be supplemented by specific examples of two dimensional VCSEL array coupling.", "author_names": [ "Dominic Francis Siriani", "Kent D Choquette" ], "corpus_id": 91832032, "doc_id": "91832032", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Coherent Coupling of Vertical Cavity Surface Emitting Laser Arrays", "venue": "", "year": 2012 }, { "abstract": "Electronically controlled optical beam steering is sensitive and reliable. It is significant for phased laser radar applications. We reported the experimental characterization of three element coherent vertical cavity surface emitting laser arrays and demonstrated two dimensional electronical beam steering. 2 D far field patterns, near field patterns, and the spectra of the beam under different current conditions were measured. It is demonstrated that beam steering is continuous and predicted. Above 17.9% of the total power of the array is concentrated in the central lobe, showing high coupling efficiency. Up to a 3.26deg shift angle from normal is demonstrated. The beam steering mechanism of frequency detuning between the three cavities was analyzed via both theory and experiment.", "author_names": [ "Meng Xun", "Yun Sun", "Jing-tao Zhou", "Chen Sen Xu", "Yiyang Xie", "Haixia Wang", "Qiang Kan", "Zhi Jin", "Xinyu Liu", "Dexin Wu" ], "corpus_id": 197627182, "doc_id": "197627182", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Two dimensional beam steering analysis in a phase coupled vertical cavity surface emitting laser array", "venue": "OSA Continuum", "year": 2019 }, { "abstract": "Mechanical free, high power, high beam quality two dimensional (2D) beam scanning lasers are in high demand for various applications including sensing systems for smart mobility, object recognition systems, and adaptive illuminations. Here, we propose and demonstrate the concept of dually modulated photonic crystals to realize such lasers, wherein the positions and sizes of the photonic crystal lattice points are modulated simultaneously. We show using nano antenna theory that this photonic nanostructure is essential to realize 2D beam scanning lasers with high output power and high beam quality. We also fabricate an on chip, circuit driven array of dually modulated photonic crystal lasers with a 10 x 10 matrix configuration having 100 resolvable points. Our device enables the scanning of laser beams over a wide range of 2D directions in sequence and in parallel, and can be flexibly designed to meet application specific demands. Beam scanning lasers are required for systems for smart mobility, object recognition, and adaptive illuminations. The authors demonstrate dually modulated photonic crystals, wherein the positions and sizes of the photonic crystal lattice points are modulated simultaneously, to achieve mechanical free, 2D beam scanning.", "author_names": [ "Ryoichi Sakata", "Kenji Ishizaki", "Menaka de Zoysa", "Shin Fukuhara", "Takuya Inoue", "Yoshinori Tanaka", "Kintaro Iwata", "Ranko Hatsuda", "Masahiro Yoshida", "John Gelleta", "Susumu Noda" ], "corpus_id": 220612456, "doc_id": "220612456", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Dually modulated photonic crystals enabling high power high beam quality two dimensional beam scanning lasers", "venue": "Nature Communications", "year": 2020 }, { "abstract": "A smile suppressed high power InGaN laser array has been developed for a high beam quality material processing light source. The smile effect becomes apparent especially in InGaN laser array with large chip curvature due to lattice mismatch of epitaxial growth layers. To reduce the smile, periodic grooves are introduced to the epitaxial layers for removing the origin of strain. It also enables a two dimensional strain management of remaining epitaxial layers. This technology improves the chip curvature within micron range, i.e. as small as 0.3 mm in a 9 mm width InGaN laser array. We have successfully realized reducing the smile to 0.4 mm without degrading the laser light output characteristics.", "author_names": [ "Shinichiro Nozaki", "Masao Kawaguchi", "Takahiro Nibu", "Hiroyuki Hagino", "Atsunori Mochida", "Takashi Kano", "S Takigawa", "Takuma Katayama", "Tsuyoshi Tanaka", "Kouji Oomori" ], "corpus_id": 215790170, "doc_id": "215790170", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A high power InGaN laser array with built in smile suppression structure", "venue": "LASE", "year": 2020 }, { "abstract": "We demonstrate coherent beam combination of two dimensional high power fiber amplifier array using stochastic parallel gradient descent (SPGD) algorithm. Four polarization maintained fiber amplifiers are tiled side by side into a 2x2 laser array with a fill factor of 54% in the near field. Phase control on the fiber amplifiers are performed by running SPGD algorithm on a digital dignal processor with updating rate of 50 000 Hz/channel. Coherent beam combination of the four fiber amplifiers with a total output power of 60.1 W using SPGD algorithm is demonstrated. Beam quality of the combined beam is computed to be BQ<1.4.", "author_names": [ "Pu Zhou", "Zejin Liu", "Xiaolin Wang", "Yanxing Ma", "Haotong Ma", "Xiaojun Xu" ], "corpus_id": 120449159, "doc_id": "120449159", "n_citations": 55, "n_key_citations": 0, "score": 0, "title": "Coherent beam combination of two dimensional high power fiber amplifier array using stochastic parallel gradient descent algorithm", "venue": "", "year": 2009 }, { "abstract": "We have fabricated and operated large two dimensional (2D) arrays of phase locked surface emitting semiconductor lasers. The arrays were fabricated by reactive ion beam etching of epitaxial Fabry Perot resonators comprising GaAs/AlGaAs quantum wells surrounded by AlAs AlGaAs quarter wave mirrors. Different arrays corresponding to different pixel size (2 5 mm) and spacing (1 2 mm) were produced to investigate evanescent coupling between pixels. The arrays were photopumped so that the array size could be conveniently varied from 1x1, 2x2, up to 20x20. Except for the 1x1 which emits a circular pattern, all arrays exhibit a well defined four lobed far field pattern in agreement with our theoretical analysis of the optical modes which predicts domination by the 2D out of phase eigenmode. As a consequence this pattern can be understood with simple Fraunhofer diffraction theory. The angular spread of the lobes, determined by the periodicity of the array elements, is 10deg for the array with element size/spacing.", "author_names": [ "Paul L Gourley", "Mial E Warren", "G Ronald Hadley", "Gregory A Vawter", "Thomas M Brennan", "Burrell E Hammons" ], "corpus_id": 122518998, "doc_id": "122518998", "n_citations": 77, "n_key_citations": 1, "score": 0, "title": "Coherent beams from high efficiency two dimensional surface emitting semiconductor laser arrays", "venue": "", "year": 1991 }, { "abstract": "Summary form only given. The coherent output from semiconductor laser sources can be increased by coherently combining the light from an array of many individual lasers in an external Talbot cavity configuration. As the number of elements increases, the mode discrimination required for strong coherence can be maintained by using two dimensional laser arrays. Here we present results on the phase locking of a 2 dimensional 12/spl times/12 surface emitting gain array in an external Talbot cavity.<ETX>", "author_names": [ "Steve Sanders", "Robert G Waarts", "Derek W Nam", "Dave Welch", "John C Ehlert", "William James Cassarly", "J Michael Finlan", "Kevin M Flood" ], "corpus_id": 120624699, "doc_id": "120624699", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Phase locking of a two dimensional semiconductor laser array in an external Talbot cavity", "venue": "Proceedings of LEOS '93", "year": 1993 }, { "abstract": "We demonstrate the phase locking of a 12 X 12 two dimensional surface emitting laser array to generate 1.4 W of output power in diffraction limited far field. A phase contrast imaging system is used to measure array element phases and apply corrections to an intracavity liquid crystal array.", "author_names": [ "Steve Sanders", "Robert G Waarts", "Derek W Nam", "Dave Welch", "John C Ehlert", "William James Cassarly", "J Michael Finlan", "Kevin M Flood" ], "corpus_id": 109521230, "doc_id": "109521230", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Phase locking of a two dimensional semiconductor laser array in an external Talbot cavity", "venue": "Photonics West Lasers and Applications in Science and Engineering", "year": 1994 } ]

[ { "abstract": "In this study, the electronic properties of pristine and Li doped BN flakes have been studied by first principle density functional theory and the B3LYP/6 31G(d,p) level. Accordingly, for pristine flakes, stability increases as the size increases. For doped flakes, the adsorption energy also increases as the size increases. And, for the $N H$ bond adsorption, we have the maximum stability. The distance of the adsorbed Li atom from the BN surface decreases as the adsorption place becomes farther from the symmetry point of the BN flake. For pristine BN the bond lengths do not change as the size increases, and the changes of the bond lengths of doped BN are in order of 0.01 $A$ About the gap, for pristine BN, the gap increases as the size decreases. Furthermore, for doped structures, a little spin is transferred to the doped BN layer and some states are spin polarized. A large value of the HOMO LUMO gap for pristine and spin down current leads to this point that we have a wide gap insulator for pristine BN and spin down states. While, for spin up electrons, the gap amounts are between 2 and 2.9 eV posses that we have a semiconductor. Additionally, in doped cases, by the increase of the \\alpha$ gap, the \\beta$ gap of the spin up states decreases. Frontier molecular orbitals have also been studied to discuss the ground and excited states. The trends seen in the DOS spectrum and charge distribution are also observed in the present work for pristine and Li doped BNs. Moreover, the doped BNs posses non zero dipole moments due to the asymmetry in the charge distribution. Finally, we have suggested an application for the BN as a protecting layer for a Lithium ion battery. Besides, its photoluminescence properties for optoelectronic applications have been discussed.", "author_names": [ "Narjes Kheirabadi", "Azizollah Shafiekhani" ], "corpus_id": 219558963, "doc_id": "219558963", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Intercalation of boron nitride quantum dots with Lithium: boron nitride as a protecting layer for a Lithium ion battery and a spin dependent photon emission device", "venue": "", "year": 2020 }, { "abstract": "Solid state electrolytes (SSEs) are expected to improve not only the safety but also the energy density of lithium ion batteries, especially referring to the application of most promising Li metal", "author_names": [ "Zhenyu J Zhang", "Antonio Gonzalez", "Kwang-Leong Choy" ], "corpus_id": 204107561, "doc_id": "204107561", "n_citations": 4, "n_key_citations": 0, "score": 1, "title": "Boron Nitride Enhanced Garnet Type (Li6.25Al0.25La3Zr2O12) Ceramic Electrolyte for an All Solid State Lithium Ion Battery", "venue": "ACS Applied Energy Materials", "year": 2019 }, { "abstract": "Owing to their extraordinary thermal, mechanical, optical, and electrical properties, boron nitride nanotubes (BNNTs) have been attracting considerable attention in various scientific fields, making it more promising as a nanomaterial compared to other nanotubes. Recent studies reported that BNNTs exhibit better properties than carbon nanotubes, which have been extensively investigated for most environment energy applications. Irrespective of its chirality, BNNT is a constant wide bandgap insulator, exhibiting thermal oxidation resistance, piezoelectric properties, high hydrogen adsorption, ultraviolet luminescence, cytocompatibility, and stability. These unique properties of BNNT render it an exceptional material for separation applications, e.g. membranes. Recent studies reported that water filtration, gas separation, sensing, and battery separator membranes can considerably benefit from these properties. That is, flux, rejection, anti fouling, sensing, structural, thermal, electrical, and optical properties of membranes can be enhanced by the contribution of BNNTs. Thus far, a majority of studies have focused on molecular simulation. Hence, the requirement of an extensive review has emerged. In this perspective article, advanced properties of BNNTs are analyzed, followed by a discussion on the advantages of these properties for membrane science with an overview of the current literature. We hope to provide insights into BNNT materials and accelerate research for environment energy applications.", "author_names": [ "Numan Yanar", "Eunmok Yang", "Hosik Park", "Moon Son", "Heechul Choi" ], "corpus_id": 229324035, "doc_id": "229324035", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Boron Nitride Nanotube (BNNT) Membranes for Energy and Environmental Applications", "venue": "Membranes", "year": 2020 }, { "abstract": "There is an increasing demand for fast charging and high capacity lithium ion batteries. However, conventional Li ion battery chemistries cannot meet the stringent requirements of these demands due to the poor performance of graphite anodes, especially on safety during fast charging. Finding the right anode material that can replace conventional graphite while providing high capacity is very challenging. Today, lithium titanium oxide (LTO) is considered one of the most attractive anode materials that can provide the desired ultra fast charging ability >10C) with high safety. However, it has many serious drawbacks when compared to the existing graphite anodes, including poor intrinsic conductivity, narrow electrochemical window, etc. Extensive research has been done to overcome these problems, especially in developing new LTO composite materials with reduced graphene oxide. However, even these methods have rapid capacity fading at high current densities, >5C, due to increased internal resistance and polarization losses. Here, we demonstrate an effective way to improve LTO composite materials by developing unique nanoengineered three dimensional frameworks with hexagonal boron nitride (h BN) addition. Li ion cells with h BN incorporation exhibit excellent performance and operational stability, especially at fast and ultra fast charging rates, >10C.", "author_names": [ "Onur Ergen" ], "corpus_id": 219114951, "doc_id": "219114951", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Hexagonal boron nitride incorporation to achieve high performance Li4Ti5O12 electrodes", "venue": "", "year": 2020 }, { "abstract": "Abstract Solid state polymer electrolyte is a promising candidate for the next generation of all solid state lithium ion batteries due to its advantages of light weight, high stability to electrodes, non flammable, sufficient mechanical strength to prevent lithium dendrite growth, and low cost. Here, through a facile and cost effective route, two dimensional boron nitride (BN) is applied as an efficient additive in a polymer/salt hybrid electrolyte, which brings about high ionic conductivity, improved mechanical strength and intimate interfacial contact between the electrolyte and electrodes. A 1% BN addition into polymer/salt hybrid electrolyte membrane exhibits a high conductivity of 1.82 x 10 3 S/cm at room temperature. Indentation test shows the BN modified hybrid electrolyte possesses an enhanced hardness (4.99 MPa) and Young's modulus (0.133 GPa) The 1% BN modified hybrid electrolyte is demonstrated to effectively suppress the lithium dendrite growth during repeated striping and plating of lithium. As a result, the battery of lithium metal anode paired with LiFePO4 cathode and using the as fabricated 1% BN enhanced polymer/salt hybrid electrolyte exhibits improved cycling performance with high Coulombic efficiency (over 98%", "author_names": [ "Zhenyu J Zhang", "Ruiz Gonzalez Antonio", "Kwang-Leong Choy" ], "corpus_id": 198355519, "doc_id": "198355519", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Boron nitride enhanced polymer/salt hybrid electrolytes for all solid state lithium ion batteries", "venue": "Journal of Power Sources", "year": 2019 }, { "abstract": "A high surface area, highly crystalline boron nitride aerogel synthesized with nonhazardous reactants has been loaded with crystalline platinum nanoparticles to form a novel nanomaterial that exhibits many advantages for use in a catalytic gas sensing application. The platinum nanoparticle loaded boron nitride aerogel integrated onto a microheater platform allows for calorimetric propane detection. The boron nitride aerogel exhibits thermal stability up to 900 degC and supports disperse platinum nanoparticles, with no sintering observed after 24 h of high temperature testing. The high thermal conductivity and low density of the boron nitride aerogel result in an order of magnitude faster response and recovery times <2 s) than reported on alumina support and allow for 10% duty cycling of the microheater with no loss in sensitivity. The resulting 1.5 mW sensor power consumption is two orders of magnitude less than commercially available catalytic gas sensors and unlocks the potential for wireless, battery powered catalytic gas sensing.", "author_names": [ "Anna Harley-Trochimczyk", "Thang Pham", "Jiyoung Chang", "Ernest Chen", "Marcus Andre Worsley", "Alex Zettl", "William Mickelson", "Roya Maboudian" ], "corpus_id": 55345433, "doc_id": "55345433", "n_citations": 51, "n_key_citations": 2, "score": 0, "title": "Platinum Nanoparticle Loading of Boron Nitride Aerogel and Its Use as a Novel Material for Low Power Catalytic Gas Sensing", "venue": "", "year": 2016 }, { "abstract": "One of the low dimensional Boron Nitride (BN) forms, namely, cubic BN (c BN) nanodots (NDs) offers a variety of novel opportunities in battery, biology, deep ultraviolet light emitting diodes, sensors, filters, and other optoelectronic applications. To date, the attempts towards producing c BN NDs were mainly performed under extreme high temperature/high pressure conditions and resulted in c BN NDs with micrometer sizes, mixture of different BN phases, and containing process related impurities/contaminants. To enhance device performance for those applications by taking advantage of size effect, pure, sub 100 nm c BN NDs are necessary. In this paper, we report self assembled growth of c BN NDs on cobalt and nickel substrates by plasma assisted molecular beam epitaxy. It is found that the nucleation, formation, and morphological properties of c BN NDs can be closely correlated with the nature of substrate including catalysis effect, lattice mismatch induced strain, and roughness, and growth conditions, in particular, growth time and growth temperature. The mean lateral size of c BN NDs on cobalt scales from 175 nm to 77 nm with the growth time. The growth mechanism of c BN NDs on metal substrates is concluded to be Volmer Weber (VW) mode. A simplified two dimensional numerical modeling shows that the elastic strain energy plays a key role in determining the total formation energy of c BN NDs on metals.", "author_names": [ "Alireza Khanaki", "Zhongguang Xu", "Hao Tian", "Renjing Zheng", "Zheng Zuo", "Jian-Guo Zheng", "Jianlin Liu" ], "corpus_id": 1377124, "doc_id": "1377124", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Self assembled Cubic Boron Nitride Nanodots", "venue": "Scientific Reports", "year": 2017 }, { "abstract": "Abstract Polymer electrolytes composed of an acrylonitrile and polyethylene glycol methacrylate copolymer poly(AN co PEGMA) with addition of NaClO4 are studied by impedance spectroscopy, differential scanning calorimetry (DSC) fourier transform infrared (FTIR) X ray diffraction (XRD) scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) Hexagonal boron nitride (hBN) particles are having increasing interest owing to mechanical properties, thermal stability, chemical stability and good lubrication property. In this study, hBN was used as an inorganic filler. FTIR spectroscopy was used to examine the interactions between the host polymer and both NaClO4 salt and nano hBN particles. The thermal properties of the composites were studied using TGA and DSC tests. TGA results showed that all the composites membranes were thermally stable till 300degC with one step degradation. Surface morphology of the films was examined with SEM which also reveals the homogeneous dispersion of nano hBN in the polymer matrix. Ionic conductivity was studied with impedance spectroscopy, the results showed that the ionic conductivity increases with increasing PEGMA ratio. ANcoPEGMA 11 20Na (EO:Na ratio=20) sample showed maximum ion conductivity of approximately 3.6x10 4 S cm 1 at 100degC. This is because ANcoPEGMA 11 20Na has highest percentage of PEGMA and highest number of Na+ ion per EO groups.", "author_names": [ "Abubakar Hamisu", "Sevim Unugur Celik" ], "corpus_id": 102659728, "doc_id": "102659728", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Poly(AN co PEGMA)/hBN/NaClO4 composite electrolytes for sodium ion battery", "venue": "", "year": 2017 }, { "abstract": "The reliability and safety of lithium ion batteries can be affected by overheating issues. Phase change materials like paraffin due to their large heat capacities are among the best solutions for the thermal management of batteries. In this investigation, multiscale modelling techniques were developed to explore the efficiency in the thermal management of rechargeable batteries through employing the paraffin composite structures. A combined atomistic continuum multiscale modelling was conducted to evaluate the thermal conductivity of paraffin reinforced with graphene or hexagonal boron nitride nanosheet additives. In addition, heat generation during a battery service was simulated using the Newman's electrochemical model. Finally, three dimensional heat transfer models were constructed to investigate the effectiveness of various paraffin composite structures in the thermal management of a battery system. Interestingly, it was found that the thermal conductivity of paraffin nanocomposites can be enhanced by several times but that does not yield significant improvement in the batteries thermal management over the pure paraffin. The acquired findings can be useful not only for the modelling of nanocomposites but more importantly for the improvement of phase change materials design to enhance the thermal management of rechargeable batteries and other electronic devices.", "author_names": [ "Bohayra Mortazavi", "Hongliu Yang", "Farzad Mohebbi", "Gianaurelio Cuniberti", "Timon Rabczuk" ], "corpus_id": 113784774, "doc_id": "113784774", "n_citations": 95, "n_key_citations": 3, "score": 0, "title": "Graphene or h BN paraffin composite structures for the thermal management of Li ion batteries: A multiscale investigation", "venue": "", "year": 2017 }, { "abstract": "Li metal anodes have attracted considerable research interest due to their low redox potential 3.04 V vs standard hydrogen electrode) and high theoretical gravimetric capacity of 3861 mAh/g. Battery technologies using Li metal anodes have shown much higher energy density than current Li ion batteries (LIBs) such as Li O2 and Li S systems. However, issues related to dendritic Li formation and low Coulombic efficiency have prevented the use of Li metal anode technology in many practical applications. In this paper, a thermally conductive separator coated with boron nitride (BN) nanosheets has been developed to improve the stability of the Li metal anodes. It is found that using the BN coated separator in a conventional organic carbonate based electrolyte results in the Coulombic efficiency stabilizing at 92% over 100 cycles at a current rate of 0.5 mA/cm(2) and 88% at 1.0 mA/cm(2) The improved Coulombic efficiency and reliability of the Li metal anodes is due to the more homogeneous thermal distribution resulting from the thermally conductive BN coating and to the smaller surface area of initial Li deposition.", "author_names": [ "Wei Luo", "Lihui Zhou", "Kun Fu", "Zhi Yang", "Jiayu Wan", "Michael Manno", "Yonggang Yao", "Hongli Zhu", "Bao Yang", "Liangbing Hu" ], "corpus_id": 206727636, "doc_id": "206727636", "n_citations": 213, "n_key_citations": 1, "score": 0, "title": "A Thermally Conductive Separator for Stable Li Metal Anodes.", "venue": "Nano letters", "year": 2015 } ]

[ { "abstract": "A method includes providing a semiconductor substrate having first and second regions that are doped with first and second dopants respectively. The first and second dopants are of opposite types. The method further includes epitaxially growing a first semiconductor layer that is doped with a third dopant. The first and third dopants are of opposite types. The method further includes depositing a dielectric hard mask (HM) layer over the first semiconductor layer; patterning the dielectric HM layer to have an opening over the first region; extending the opening towards the semiconductor substrate; and epitaxially growing a second semiconductor layer in the opening. The second semiconductor layer is doped with a fourth dopant. The first and fourth dopants are of a same type. The method further includes removing the dielectric HM layer; and performing a first CMP process to planarize both the first and second semiconductor layers.", "author_names": [ "Quentin A Pankhurst", "James Connolly", "S K Jones", "Jon Dobson" ], "corpus_id": 51768859, "doc_id": "51768859", "n_citations": 4471, "n_key_citations": 83, "score": 1, "title": "TOPICAL REVIEW: Applications of magnetic nanoparticles in biomedicine", "venue": "", "year": 2003 }, { "abstract": "OBJECTIVE It has been well established that schizophrenic patients have neurocognitive deficits, but it is not known how these deficits influence the daily lives of patients. The goal of this review was to determine which, if any, neurocognitive deficits restrict the functioning of schizophrenic patients in the outside world. METHOD The author reviewed studies that have evaluated neurocognitive measures as predictors and correlates of functional outcome for schizophrenic patients. The review included 1) studies that have prospectively evaluated specific aspects of neurocognition and community (e.g. social and vocational) functioning (six studies) 2) all known studies of neurocognitive correlates of social problem solving (five studies) and 3) all known studies of neurocognitive correlates and predictors of psychosocial skill acquisition (six studies) RESULTS Despite wide variation among studies in the selection of neurocognitive measures, some consistencies emerged. The most consistent finding was that verbal memory was associated with all types of functional outcome. Vigilance was related to social problem solving and skill acquisition. Card sorting predicted community functioning but not social problem solving. Negative symptoms were associated with social problem solving but not skill acquisition. Notably, psychotic symptoms were not significantly associated with outcome measures in any of the studies reviewed. CONCLUSIONS Verbal memory and vigilance appear to be necessary for adequate functional outcome. Deficiencies in these areas may prevent patients from attaining optimal adaptation and hence act as \"neurocognitive rate limiting factors.\" On the basis of this review of the literature, a series of hypotheses are offered for follow up studies.", "author_names": [ "M F Green" ], "corpus_id": 21248715, "doc_id": "21248715", "n_citations": 3336, "n_key_citations": 139, "score": 0, "title": "What are the functional consequences of neurocognitive deficits in schizophrenia?", "venue": "The American journal of psychiatry", "year": 1996 }, { "abstract": "Direct fabrication of large micropatterned single crystals. p1205 21 Feb 2003. (news) Academy plucks best biophysicists from a sea of mediocrity. p994 14 Feb 2003.", "author_names": [ "Aaas News", "Eric Lu", "Minmin Zhou", "Rong Mocsai", "Attila Myers", "E Huang", "B Jackson", "Davide Ferrari", "V Tybulewicz", "Victor Lowell", "Clifford A Lepore", "J Koretzky", "Gary Kahn", "Mark L", "Frederic Achard", "Hugh Douglas Eva", "Ernst-Detlef See Also Schulze", "Jairaj K Acharya", "Usha Acharya", "Shetal Patel", "E Koundakjian", "Kunio Nagashima", "Xianlin Han", "Daniel L Adams", "Jonathan C And Horton", "", "Melissa D Adams", "Mitch McVey", "Jeff Sekelsky", "John W Adamson", "Gerd G Kochendoerfer", "A W Adeleke", "A See Kamdem-Toham", "Alan Aderem", "C Picard", "Gerald H Haug", "Girish S Agarwal", "Marlan O Scully", "Hugo Aguilaniu", "Lena Gustafsson", "Michel Rigoulet", "Thomas Nystrom", "Ferhaan Ahmad", "Joachim P Schmitt", "Misako Aida", "Salai C Ammal", "Joanna Aizenberg", "David A Muller", "John L Grazul", "Don R Hamann", "James W Ajioka", "C J Su", "Aravind B Akella", "M S Alam", "F Gao", "Ahmet Alatas", "Harald Sinn", "Titus V Albu", "Peter S Zuev", "Maher Al-Dayeh", "Joseph R Dwyer", "Abdulaziz Al-ghonaium", "Sami Al-Hajjar", "Sulaiman Al-Jumaah", "Andrei Allakhverdov", "V A Pokrovsky", "Andrew P See Brown", "James H Allen", "James H Gillooly" ], "corpus_id": 15642412, "doc_id": "15642412", "n_citations": 70612, "n_key_citations": 5625, "score": 0, "title": "\"A and B\"", "venue": "Sophonisba Breckinridge", "year": 2019 }, { "abstract": "1. Introduction. 2. Power Semiconductor Diodes and Circuits. 3. Diode Rectifiers. 4. Power Transistors. 5. DC DC Converters. 6. Pulse width Modulated Inverters. 7. Thyristors. 8. Resonant Pulse Inverters. 9. Multilevel Inverters. 10. Controlled Rectifiers. 11. AC Voltage Controllers. 12. Static Switches. 13. Flexible AC Transmission Systems. 14. Power Supplies. 15. DC Drives. 16. AC Drives. 17. Gate Drive Circuits. 18. Protection of Devices and Circuits. Appendices: Three phase Circuits, Magnetic Circuits, Switching Functions of Converters, DC Transient Analysis, Fourier Analysis, Thyristor Commutation Techniques, Data Sheets.", "author_names": [ "M H Rashid" ], "corpus_id": 108968918, "doc_id": "108968918", "n_citations": 2288, "n_key_citations": 114, "score": 0, "title": "Power Electronics: Circuits, Devices and Applications", "venue": "", "year": 1993 }, { "abstract": "Electrochemical energy conversion devices are pervasive in our daily lives. Batteries, fuel cells and supercapacitors belong to the same family of energy conversion devices. They are all based on the fundamentals of electrochemical thermodynamics and kinetics. All three are needed to service the wide energy requirements of various devices and systems. Neither batteries, fuel cells nor electrochemical capacitors, by themselves, can serve all applications.", "author_names": [ "Martin Winter", "Ralph J Brodd" ], "corpus_id": 3091080, "doc_id": "3091080", "n_citations": 5298, "n_key_citations": 57, "score": 0, "title": "What are batteries, fuel cells, and supercapacitors?", "venue": "Chemical reviews", "year": 2004 }, { "abstract": "The idea of reserve against brain damage stems from the repeated observation that there does not appear to be a direct relationship between the degree of brain pathology or brain damage and the clinical manifestation of that damage. This paper attempts to develop a coherent theoretical account of reserve. One convenient subdivision of reserve models revolves around whether they envision reserve as a passive process, such as in brain reserve or threshold, or see the brain as actively attempting to cope with or compensate for pathology, as in cognitive reserve. Cognitive reserve may be based on more efficient utilization of brain networks or of enhanced ability to recruit alternate brain networks as needed. A distinction is suggested between reserve, the ability to optimize or maximize normal performance, and compensation, an attempt to maximize performance in the face of brain damage by using brain structures or networks not engaged when the brain is not damaged. Epidemiologic and imaging data that help to develop and support the concept of reserve are presented. (JINS, 2002, 8, 448 460.", "author_names": [ "Yaakov Stern" ], "corpus_id": 9902333, "doc_id": "9902333", "n_citations": 2779, "n_key_citations": 222, "score": 0, "title": "What is cognitive reserve? Theory and research application of the reserve concept", "venue": "Journal of the International Neuropsychological Society", "year": 2002 }, { "abstract": "This paper describes a technique that exploits the statistical delay variations of wires and transistors across ICs to build a secret key unique to each IC. To explore its feasibility, we fabricated a candidate circuit to generate a response based on its delay characteristics. We show that there exists enough delay variation across ICs implementing, the proposed circuit to identify individual ICs. Further. the circuit, functions reliably over a practical range of environmental variation such as temperature and voltage.", "author_names": [ "J W Lee", "Daihyun Lim", "Blaise Gassend", "G Edward Suh", "Marten van Dijk", "Srinivas Devadas" ], "corpus_id": 617735, "doc_id": "617735", "n_citations": 691, "n_key_citations": 75, "score": 0, "title": "A technique to build a secret key in integrated circuits for identification and authentication applications", "venue": "2004 Symposium on VLSI Circuits. Digest of Technical Papers (IEEE Cat. No.04CH37525)", "year": 2004 }, { "abstract": "Columns, Connections, and Correlations What is the nature of interactions between neurons in neural circuits? The prevalent hypothesis suggests that dense local connectivity causes nearby cortical neurons to receive substantial amounts of common input, which in turn leads to strong correlations between them. Now two studies challenge this view, which impacts our fundamental understanding of coding in the cortex. Ecker et al. (p. 584) investigated the statistics of correlated firing in pairs of neurons from area V1 of awake macaque monkeys. In contrast to previous studies, correlations turned out to be very low, irrespective of the stimulus being shown to the animals, the distances of the recording sites, and the similarity of the neuron's receptive fields or response properties. In an accompanying modeling and recording paper, Renart et al. (p. 587) demonstrate how it is possible to have zero noise correlation, even among cells with common input. A general theoretical description of correlations in highly connected recurrent neuronal circuits. Correlated spiking is often observed in cortical circuits, but its functional role is controversial. It is believed that correlations are a consequence of shared inputs between nearby neurons and could severely constrain information decoding. Here we show theoretically that recurrent neural networks can generate an asynchronous state characterized by arbitrarily low mean spiking correlations despite substantial amounts of shared input. In this state, spontaneous fluctuations in the activity of excitatory and inhibitory populations accurately track each other, generating negative correlations in synaptic currents which cancel the effect of shared input. Near zero mean correlations were seen experimentally in recordings from rodent neocortex in vivo. Our results suggest a reexamination of the sources underlying observed correlations and their functional consequences for information processing.", "author_names": [ "Alfonso Renart", "Jaime de la Rocha", "Peter Bartho", "Liad Hollender", "Nestor Parga", "Alex D Reyes", "Kenneth D Harris" ], "corpus_id": 5614557, "doc_id": "5614557", "n_citations": 925, "n_key_citations": 103, "score": 0, "title": "The Asynchronous State in Cortical Circuits", "venue": "Science", "year": 2010 }, { "abstract": "Transcranial magnetic stimulation (TMS) is commonly used to activate or inactivate specific cortical areas in a noninvasive manner. Because of technical constraints, the precise effects of TMS on cortical circuits are difficult to assess experimentally. Here, this issue is investigated by constructing a detailed model of a portion of the thalamocortical system and examining the effects of the simulated delivery of a TMS pulse. The model, which incorporates a large number of physiological and anatomical constraints, includes 33,000 spiking neurons arranged in a 3 layered motor cortex and over 5 million intra and interlayer synaptic connections. The model was validated by reproducing several results from the experimental literature. These include the frequency, timing, dose response, and pharmacological modulation of epidurally recorded responses to TMS (the so called I waves) as well as paired pulse response curves consistent with data from several experimental studies. The modeled responses to simulated TMS pulses in different experimental paradigms provide a detailed, self consistent account of the neural and synaptic activities evoked by TMS within prototypical cortical circuits.", "author_names": [ "Steve K Esser", "Sean L Hill", "Giulio Tononi" ], "corpus_id": 16246166, "doc_id": "16246166", "n_citations": 132, "n_key_citations": 9, "score": 0, "title": "Modeling the effects of transcranial magnetic stimulation on cortical circuits.", "venue": "Journal of neurophysiology", "year": 2005 }, { "abstract": "Partial table of contents: Overview of Power Semiconductor Switches. Computer Simulation of Power Electronic Converters and Systems. GENERIC POWER ELECTRONIC CIRCUITS. dc dc Switch Mode Converters. Resonant Converters: Zero Voltage and/or Zero Current Switchings. POWER SUPPLY APPLICATIONS. Power Conditioners and Uninterruptible Power Supplies. MOTOR DRIVE APPLICATIONS. dc Motor Drives. Induction Motor Drives. Synchronous Motor Drives. OTHER APPLICATIONS. Residential and Industrial Applications. Optimizing the Utility Interface with Power Electronic Systems. SEMICONDUCTOR DEVICES. Basic Semiconductor Physics. Power Diodes. Power MOSFETs. Thyristors. Emerging Devices and Circuits. PRACTICAL CONVERTER DESIGN CONSIDERATIONS. Snubber Circuits. Gate and Base Drive Circuits. Design of Magnetic Components. Index.", "author_names": [ "Ned Mohan", "T M Undeland", "William P Robbins" ], "corpus_id": 109363530, "doc_id": "109363530", "n_citations": 5582, "n_key_citations": 245, "score": 0, "title": "Power Electronics: Converters, Applications and Design", "venue": "", "year": 1989 } ]

[ { "abstract": "Trench formation and corner rounding are the key processes to demonstrate high voltage trench based vertical GaN devices. In this work, we developed a damage free corner rounding technology combining Tetramethylammonium hydroxide wet etching and piranha clean. By optimizing the inductively coupled plasma dry etching conditions and applying the rounding technology, two main trench shapes were demonstrated: flat bottom rounded trench and tapered bottom rounded trench. TCAD simulations were then performed to investigate the impact of trench shapes and round corners on device blocking capability. GaN trench metal insulator semiconductor barrier Schottky rectifiers with different trench shapes were fabricated and characterized. A breakdown voltage over 500 V was obtained in the device with flat bottom rounded trenches, compared to 350 V in the device with tapered bottom rounded trenches and 150 V in the device with non rounded trenches. Both experimental and simulation results support the use of rounded flat b.", "author_names": [ "Yuhao Zhang", "Min-Chul Sun", "Zhihong Liu", "Daniel Piedra", "Jie Hu", "Xiang Yang Gao", "Tomas Palacios" ], "corpus_id": 92994982, "doc_id": "92994982", "n_citations": 46, "n_key_citations": 1, "score": 0, "title": "Trench formation and corner rounding in vertical GaN power devices", "venue": "", "year": 2017 }, { "abstract": "(54) TOPCORNER ROUNDING FOR SHALLOW 5,203,957 4/1993 Yoo et al. 156/643 TRENCH ISOLATION 5,654.232 8/1997 Gardner 438/661 5,837,615 11/1998 Rostoker 438/711 (75) Inventors: Hsien Kuang Chiu, Taoyuan; 5,874,317 2/1999 Stolmeijer 437/67 Fang Cheng Chen; Hun Jan Tao, both 5,915,195 6/1999 Fulford, Jr. et al. 438/254 of Hsin Chu, all of (TW) 6,074,954 6/2000 Lill et al. 438/710 6,143,666 11/2000 Lin et al. 438/725 (73) Assignee: Taiwan Semiconductor Manufacturing Company, Hsin Chu cited by examiner (TW)", "author_names": [ "Hun-Jan Tao" ], "corpus_id": 209504308, "doc_id": "209504308", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "TOP CORNER ROUNDING FOR SHALLOW TRENCH ISOLATION FIELD OF THE INVENTION", "venue": "", "year": 2017 }, { "abstract": "In this work, a novel method for shallow trench isolation (STI) top corner rounding (TCR) is presented. Different from conventional methods, such as liner oxidation or STI anneal, STI top corner with a curvature diameter of about 35 nm is achieved by STI etch process. And the mechanism of its benefit for chip's leakage and SRAM performance is studied. It's found that the big corner can reduce about 9% chip leakage and also improve SRAM performance. This can expand device window and improve product's yield stability.", "author_names": [ "Lin Gu" ], "corpus_id": 195831720, "doc_id": "195831720", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "A Novel Method for STI Top Corner Rounding by Etch Process to Improve Leakage and SRAM Performance", "venue": "2019 China Semiconductor Technology International Conference (CSTIC)", "year": 2019 }, { "abstract": "We have investigated the rounding of micron sized trenches fabricated on Si(001) substrates during annealing in hydrogen ambient in a temperature range of 1000 to 1100 degC, especially the effect of hydrogen pressure on the rate of rounding. Observing the profiles of the trenches annealed under hydrogen pressures from 10 up to 760 Torr by scanning electron microscopy, we have found that the rate of corner rounding decreases with increasing hydrogen pressure. It was also found that these rates of corner rounding are smaller than that during annealing in atmospheric argon ambient. This result suggests that adsorbed hydrogen suppresses the surface self diffusion, by which the corner rounding occurs. We present the contour map of corner curvature in the process parameter space of hydrogen pressure versus annealing temperature for an annealing time of 3 min.", "author_names": [ "Hitoshi Kuribayashi", "Ryosuke Shimizu", "Koichi Sudoh", "Hiroshi Iwasaki" ], "corpus_id": 96138472, "doc_id": "96138472", "n_citations": 19, "n_key_citations": 1, "score": 0, "title": "Hydrogen pressure dependence of trench corner rounding during hydrogen annealing", "venue": "", "year": 2004 }, { "abstract": "A new STI (Shallow Trench Isolation) corner rounding technique with MSTS (Micro Structure Transformation of Silicon) which utilizes Si migration phenomenon with hydrogen ambient annealing is proposed and applied to 0.15 /spl mu/m CMOS technology. Highly controlled corner rounding radius is achieved without high temperature oxidation process. Thus it is free from defect generation and undesirable impurity diffusion in the Si substrate. Subthreshold current due to parasitic corner transistors of the STI structure is effectively suppressed and the reverse narrow channel effect is controlled down to 0.2 /spl mu/m channel width.", "author_names": [ "S Matsuda", "Tatsuhiro Sato", "Hisao Yoshimura", "Yoshiyuki Takegawa", "A Sudo", "Ichiro Mizushima", "Yoshitaka Tsunashima", "Yoshiaki Toyoshima" ], "corpus_id": 25238138, "doc_id": "25238138", "n_citations": 32, "n_key_citations": 2, "score": 0, "title": "Novel corner rounding process for shallow trench isolation utilizing MSTS (Micro Structure Transformation of Silicon)", "venue": "International Electron Devices Meeting 1998. Technical Digest (Cat. No.98CH36217)", "year": 1998 }, { "abstract": "In this work, we first establish the relationship between corner leakage and corner rounding through device simulation. Then, we demonstrate a novel method to produce corner rounding, using a post CMP, high temperature re oxidation process (HTR STI) A semi empirical model correlating rounding with re oxidation and nitride mask thickness is derived from mechanical studies. Finally, we show the electrical properties of devices with HTR STI for the 0.18 /spl mu/m technology.", "author_names": [ "C -P Chang", "Chien-Shing Pai", "Frieder H Baumann", "C -T Liu", "Conor S Rafferty", "Mark R Pinto", "E J Lloyd", "M K Bude", "Fred P Klemens", "John F Miner", "Kin P Cheung", "Jennifer I Colonell", "Warren Y Lai", "Hem M Vaidya", "Steven James Hillenius", "R C Liu", "James T Clemens" ], "corpus_id": 45401355, "doc_id": "45401355", "n_citations": 28, "n_key_citations": 1, "score": 0, "title": "A highly manufacturable corner rounding solution for 0.18 /spl mu/m shallow trench isolation", "venue": "International Electron Devices Meeting. IEDM Technical Digest", "year": 1997 }, { "abstract": "The shape transformation mechanism of micron size silicon trenches during high temperature annealing (ges1000degC) in hydrogen ambient was studied, focusing on the effect of hydrogen pressure on the trench corner curvature. Results demonstrated the effectiveness of this hydrogen annealing process on the reliability of gate SiO2 films; after hydrogen annealing at 1030degC for 1 min, the leakage current through trench gate SiO2 as a function of applied voltage to the poly Si gate was suppressed by over 2 orders of magnitude. The time dependent dielectric breakdown (TDDB) characteristics of the trench gate SiO2 under a constant applied stress current of 50mA/cm was significantly improved by hydrogen annealing in the initial stage <100sec) of dielectric breakdown", "author_names": [ "Ryosuke Shimizu", "Hitoshi Kuribayashi", "Reiko Hiruta", "Koichi Sudoh", "Hiroshi Iwasaki" ], "corpus_id": 25519088, "doc_id": "25519088", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Mech1anism and Control Technology of Trench Corner Rounding by Hydrogen Annealing for Highly Reliable Trench MOSFET", "venue": "2006 IEEE International Symposium on Power Semiconductor Devices and IC's", "year": 2006 }, { "abstract": "A method of forming a rounded corner in a trench isolation is provided to prevent deterioration of an electric characteristic by forming a uniform rounded corner, regardless of pattern density. A pad oxide layer(22) and a pad nitride layer(24) are formed on a semiconductor substrate(20) A photoresist is formed on the pad nitride, and then is selectively etched to form a trench photoresist pattern. The pad oxide layer and the pad nitride layer are etched by using the trench photoresist pattern as an etch stop layer to expose the substrate corresponding to the trench photoresist pattern. A buffer oxide layer is formed on the exposed substrate, and the substrate is implanted with nitrogen ion to form a nitrogen ion implanted layer. The nitrogen ion implanted layer is diffused towards a side and bottom surface of the substrate to form a nitride layer. After the buffer oxide layer and the nitride layer are removed, the substrate is etched to form a trench(25) having a rounded corner.", "author_names": [ "" ], "corpus_id": 117565947, "doc_id": "117565947", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Method for forming corner rounding in trench isolation", "venue": "", "year": 2006 }, { "abstract": "A new trench corner rounding technique has been developed by using pull back and hydrogen annealing process. This technique provides highly controllable trench corner rounding by micro structure transformation of silicon at the corner of the trench, leading to uniform gate oxide, higher breakdown voltage, and lower leakage current.", "author_names": [ "Sang-Gi Kim", "Jongdae Kim", "Jin Gun Koo", "Kee Soo Nam", "Kyoung Ik Cho" ], "corpus_id": 110811116, "doc_id": "110811116", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Trench corner rounding technology using hydrogen annealing for highly reliable trench DMOSFETs", "venue": "12th International Symposium on Power Semiconductor Devices ICs. Proceedings (Cat. No.00CH37094)", "year": 2000 }, { "abstract": "Shallow Trench Isolation (STI) technology is important for realizing high speed and high packing density complementary metal oxide semiconductor very large scale integrated (CMOS VLSI) technologies. To obtain top corner rounding in STI, a new process was evaluated. This technique utilizes Si soft etching by O2+CF4 plasma following pad oxide shift in dilute hydrofluorine (HF) solution after STI formation, which effectively suppresses subthreshold slope (hump) for n and p channel devices even when 4 V of substrate bias is applied. This technique also does not cause top corner rounding (TCR) imbalance between narrow and wide spaces caused by the conventional sidewall generation technique in pad nitride etching. This new STI formation method markedly improves STI top corner rounding. As a result, it has been found that this technique is very effective for sub 0.18 um STI formation.", "author_names": [ "Seong-Yeol Mun", "Kyeong Cheol Shin", "Ki chae Yoon", "Jong Seok Kwak", "Hyukhyun Ryu", "Yang Hee Jeong" ], "corpus_id": 120977877, "doc_id": "120977877", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Shallow Trench Isolation Top Corner Rounding Using Si Soft Etching Following Diluted Hydrofluorine Solution", "venue": "", "year": 2004 } ]

[ { "abstract": "We demonstrate a far field nano photoluminescence setup based on the combination of a hemispherical solid immersion lens (SIL) with a confocal microscope. The spatial resolution is confirmed to be 0.4 times the wavelength in vacuum in terms of half width at half maximum. The collection efficiency is found to be about five times higher than the same microscope without SIL, which is consistent with our theoretical analysis. We investigate in detail the influence of an air gap between the SIL and the sample surface on the system performance, and prove both experimentally and theoretically the tolerance of this far field system to an air gap of several micrometers. These features make the present setup an ideal system for spatially resolved spectroscopy of semiconductor nanostructures. In particular, we show two examples of such applications in which the present setup is clearly suitable: Studies of excitonic transport in quantum wells and spectroscopy of single quantum dots with emphasis on polarization depe.", "author_names": [ "Sebastian Moehl", "Hui Zhao", "B Dal Don", "Sven Wachter", "Heinz Kalt" ], "corpus_id": 119367740, "doc_id": "119367740", "n_citations": 46, "n_key_citations": 0, "score": 1, "title": "Solid immersion lens enhanced nano photoluminescence: Principle and applications", "venue": "", "year": 2003 }, { "abstract": "We investigate the in plane transport of excitons in quantum wells by nano photoluminescence. The experimental method is based on a confocal microscope with an enhanced resolution given by the introduction of a solid immersion lens. In combination with pulsed laser excitation and streak camera detection, we have access to transport phenomena on a timescale faster than the time of scattering with acoustic phonons and a length scale of the light wavelength. We use ZnSe based quantum wells as a model system since hot excitons with well defined excess energy can be formed assisted by the emission of optical phonons. This results e.g. in a periodic quenching of the excitonic transport length as function of excitation excess energy which, in comparison, is not found in GaAs quantum wells. Monte Carlo simulations of the nonlinear expansion of the luminescence spot observed as a function of time reveal the difference between the spatial profiles of the luminescence and the exciton density. The latter shows an oscillatory behaviour in time due to the dominant backscattering, when the first acoustic phonon is emitted. From this oscillation we can determine simultaneously the coherence time and length of the excitonic transport in ZnSe quantum wells. (c) 2004 WILEY VCH Verlag GmbH Co. KGaA, Weinheim)", "author_names": [ "B Dal Don", "Hui Zhao", "Gregor Schwartz", "Thomas Unkelbach", "Heinz Kalt" ], "corpus_id": 122765476, "doc_id": "122765476", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Coherence length and time of excitons in ZnSe quantum wells", "venue": "", "year": 2004 }, { "abstract": "We report investigations on excitonic transport in ZnSe quantum wells using far field nano photoluminescence enhanced by a solid immersion lens. The 250 nm spatial resolution and 5 ps temporal resolution allow the access to non classical transport regimes. From zero phonon line spectroscopy we deduce the spatial distribution of the PL intensity under different cw excitation condition and its temporal evolution after a pulsed excitation, respectively. The periodic quenching of the transport length as function of excitation excess energy and the nonlinear expansion of the PL spot observed in time resolved experiments reveal the dominance of hot exciton effects. The experimental data are well modelled by a Monte Carlo simulation. Spatially resolved phonon sideband spectroscopy is used to observe directly the coherent transport and the energy relaxation of hot excitons during transport. The coherence length is measured to be 300 400 nm at low temperatures and the excitons are found to remain hot during transport on a length scale of several micrometers.", "author_names": [ "Hui Zhao", "B Dal Don", "Sebastian Moehl", "Heinz Kalt" ], "corpus_id": 121759269, "doc_id": "121759269", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Non classical excitonic transport in quantum wells", "venue": "", "year": 2003 }, { "abstract": "We have discussed the resolution of submicron photoluminescence (PL) imaging using a solid immersion lens (SIL) which collects an evanescent light field. We apply the SIL microscope to measure PL image of a strip line patterned GaAs quantum well structure at low temperature. An improved resolution beyond diffraction limit and high collection efficiency of PL are realized.", "author_names": [ "Motoyoshi Baba", "Masahiro Yoshita", "Takeaki Sasaki", "Hidefumi Akiyama" ], "corpus_id": 123052038, "doc_id": "123052038", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Application of Solid Immersion Lens to Submicron Resolution Imaging of Nano Scale Quantum Wells", "venue": "", "year": 1999 }, { "abstract": "Summary form only given. The solid immersion lens (SIL) is an aberration free solid lens of high refractive index material with a truncated sphere shape. Combining the SIL with a standard optical microscope, PL imaging with high spatial resolution and high collection efficiency was demonstrated. In this work we applied the SIL to microscopic photoluminescence (micro PL) spectroscopy and imaging to characterize local electronic properties and real space carrier migration of sub /spl mu/m scale in facet growth GaAs quantum well (QW) structures.", "author_names": [ "Masahiro Yoshita", "Motoyoshi Baba", "Hidefumi Akiyama" ], "corpus_id": 114937758, "doc_id": "114937758", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Solid immersion photoluminescence imaging and spectroscopy with high spatial resolution on GaAs nano", "venue": "", "year": 1999 }, { "abstract": "By solid immersion photoluminescence imaging and spectroscopy, the spatial distribution of electronic states and carrier distribution and flow in GaAs facet growth nano structures and [110] quantum wells can been revealed with high spatial resolution of sub /spl mu/m scale.", "author_names": [ "Masahiro Yoshita", "Hidefumi Akiyama" ], "corpus_id": 35713844, "doc_id": "35713844", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Solid immersion photoluminescence microscopy of novel GaAs nano structures", "venue": "Technical Digest. CLEO/Pacific Rim 2001. 4th Pacific Rim Conference on Lasers and Electro Optics (Cat. No.01TH8557)", "year": 2001 }, { "abstract": "Bright single photon sources are an essential ingredient for quantum technology applications. Solid state single photon emitters are particularly suitable for the integration in on chip devices [1] However, they suffer from poor extraction efficiencies due to the high refractive index contrast between the bulk semiconductor and air, resulting in a small fraction of the emitted light being collected in free space. Several approaches to increase the extraction of light from semiconductor emitters have been implemented, including optical cavities (such as micro pillars, nanowires, and gratings) and solid immersion lenses [2] Here we report on a different approach that makes use of metallic nano rings that act as local lenses that focus the laser excitation and increase the intensity of the collected light. Such an effect is validated by finite difference time domain simulations, that we use to optimise the ring dimensions. The position of the emitters is measured with respect to alignment markers with accuracies of ~25 nm, via a photoluminescence imaging technique [3] (see Fig. 1a) Rings of inner diameter of ~440 nm are deposited on the sample surface (Fig. 1b) by means of electron beam lithography, Cr/Au deposition and chemical lift off, and centred in correspondence to single epitaxial InAs/GaAs quantum dots (QDs) The emission intensity collected from the same QD before and after ring deposition is shown in Fig 1c: the ring allows enhancements of up to a factor 25 in the intensity of single QD emission lines [4] Such ring device is scalable, simple to fabricate and broadband, compatible with any substrate and emitter, including room temperature light sources such as colloidal QDs, defect centres in diamond and in two dimensional materials.", "author_names": [ "Oliver Joe Trojak", "Luca Sapienza", "Jin Dong Song" ], "corpus_id": 26773835, "doc_id": "26773835", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Broadband emission enhancement of the extraction of light from solid state emitters by metallic nano rings", "venue": "", "year": 2017 }, { "abstract": "We report on the enhancement of the collection efficiency from epitaxial InAs/GaAs quantum dots through the deposition of metallic rings centered around single emitters, located with a nanometer scale accurate photoluminescence imaging technique. Increases of up to x17 in the brightness of the single photon emission are measured, due to an excitation and collection lensing effect. Furthermore, we demonstrate efficient confinement of visible light in disordered photonic crystal waveguides, reaching quality factors of ~10000, exceeding values previously reported in two dimensional photonic crystals. Bright single photon sources are required for various quantum information technology applications. However, the photon extraction efficiency from solid state emitters can be severely limited by the high refractive index mismatch between semiconductors (like GaAs) and air, resulting in most of the emitted light being trapped within the high index material. Several approaches have been implemented in order to increase the extraction efficiency, including photonic nanowires, micropillars and circular gratings. Solid immersion lenses, deposited on the materials surface or 3D printed via in situ lithography, have also been used to focus the excitation and the emitted light, thus increasing the emitted photon flux. We report on two different approaches that we follow to control the light matter interaction on a chip, based on broadband metallic rings and high quality light confinement in disordered photonic crystal waveguides. By implementing a photoluminescence imaging technique, we position single InAs/GaAs quantum dots grown by molecular beam epitaxy with accuracies of ~20 nm. We then deposit, by means of electron beam lithography followed by a lift off, metallic gold rings with inner diameter of ~440 nm, centered around single emitters (see Fig.1a) A confocal photoluminescence set up is used to excite selected single quantum dots with a continuous wave laser and the intensity of the single photon emission is measured on a charge coupled device (CCD) before and after the rings are deposited. (a) (b) Fig.1: (a) Scanning electron microscope image of a gold ring deposited on a GaAs chip containing InAs quantum dots. (b) Photoluminescence spectra measured from a single quantum dot, before (red) and after (blue) metallic ring deposition (temperature T 10K, laser excitation wavelength 780 nm) We measure enhancements of the emission intensity as high as ~17 (see Fig.1b) due to a lensing effect on the laser excitation light and on the emitted light. Compared to optical cavities, our ring devices are intrinsically broadband, since they do not rely on a high quality factor photonic cavity, and can therefore be implemented with any kind of solid state emitter. The performances of the rings, obtained with a much easier fabrication technique compared to in situ lithography, also surpass those of 3D printed solid immersion lenses by almost an order of magnitude. Given the dimensions in play, such metallic rings could also be fabricated using lower resolution techniques such as photolithography and nano imprinting, thus improving scalability. A variety of solid state emitters like colloidal quantum dots, defect centers in diamond and in two dimensional materials act as single photon sources operating in the visible range of wavelengths. Being able to control the spontaneous emission dynamics and efficiently confine the emitted light in high quality optical cavities is of paramount importance for the implementation of visible emitters in quantum photonic devices. However, the quality factors of visible light confinement on a chip so far reported in highly engineered photonic crystal cavities lie between a few hundreds and a few thousands: the enhancement of the light matter interaction achievable is therefore limited compared to devices operating at longer wavelengths. By using disorder as a resource, we demonstrate an improvement in the quality of light confinement on a chip of up to an order of magnitude, in optical cavities operating in the Anderson localized regime (see Fig.2) We report quality factors reaching values of ~10000 in disordered photonic crystal waveguides operating in the visible range of wavelengths on a silicon nitride platform. This is a significant improvement with respect to the state of the art and proves the potential of disorder induced confinement of visible light for on chip photonics. Fig.2: Photoluminescence spectrum of an Anderson localized cavity (symbols) and its Lorentzian fit (dashed line) showing a quality factor Q 9300+ 800 (temperature T 300K, laser excitation wavelength 473 nm) REFERENCES 1. Claudon, J. et al. \"A highly efficient single photon source based on a quantum dot in a photonic nanowire,\" Nature Photonics, Vol. 4, 174 177, 2010. 2. Somaschi, N. et al. \"Near optimal single photon sources in the solid state\" Nature Photonics, Vol. 10, 340 345, 2016. 3. Davanco, M. et al. \"A circular dielectric grating for vertical extraction of single quantum dot emission\" Applied Physics Letters, Vol. 99, 041102, 2011. 4. Serrels, K.A. et al. \"Solid immersion lens applications for nanophotonic devices\" Journal of Nanophotonics, Vol. 2, 021854, 2008. 5. Sartison, M. et al. \"Combining in situ lithography with 3D printed solid immersion lenses for single quantum dot spectroscopy\" Scientific Reports, Vol. 7, 39916, 2017. 6. Sapienza, L. et al. \"Nanoscale optical positioning of single quantum dots for bright and pure single photon emission\" Nature Communications, Vol. 7, 7833, 2015. 7. Crane, T. O.J. Trojak, L. Sapienza, \"Anderson localization of visible light\" https:/arxiv.org/abs/1605.08614v2, 2016.", "author_names": [ "Oliver Joe Trojak", "Tom Crane", "Jin Dong Song", "Luca Sapienza" ], "corpus_id": 146311020, "doc_id": "146311020", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Nano rings for improved extraction of single photons and disorder induced efficient visible light confinement on a chip", "venue": "", "year": 2017 }, { "abstract": "CaB2O4 powders and ceramics were prepared by the conventional solid state reaction. In vitro hydroxyapatite (HA) mineralization was investigated by soaking the samples in simulated body fluid (SBF) for various time periods. X ray diffraction and structural refinements, scanning electron microscopy and X ray energy dispersive spectra measurements were applied to investigate apatite formation before and after immersion in SBF. HA can easily form flower like nanostructures with nano needles even when soaked in SBF for several hours. The in vitro bioactivity of CaB2O4 was attributed to easy formation of B OH groups in the CaB2O4 structure when soaked in SBF solutions. In the process of mineralization, the luminescence evolution of Eu3+ ions, a well known structural probe, was detected by photoluminescence spectra and photoluminescence decay curves. This suggested that the process of mineralization can be monitored by the luminescence intensity of Eu3+ ions in the mineralization products. The current study will open up a new and simple in vivo avenue for in situ monitoring of hydroxyapatite conversion using a fiber luminescence spectrometer.", "author_names": [ "Shuyun Qi", "Yanlin Huang", "Yadong Li", "Peiqing Cai", "Sun Il Kim", "Hyo Jin Seo" ], "corpus_id": 135606854, "doc_id": "135606854", "n_citations": 23, "n_key_citations": 0, "score": 0, "title": "Probe spectrum measurements of Eu3+ ions as a relevant tool for monitoring in vitro hydroxyapatite formation in a new borate biomaterial.", "venue": "Journal of materials chemistry. B", "year": 2014 }, { "abstract": "In this thesis I present my research on nano scale light control using several novel approaches. I have demonstrated a planar metal nano structure with cylindrical symmetry that is designed to create a super oscillation of electromagnetic waves to focus light down to sizes smaller than the Abbe diffraction limit. For the first time this super oscillatory lens was experimentally used for imaging of nano structures. A pair of 0.3 lambda diameter nano holes with 0.16 lambda edge to edge separation were resolved. I have demonstrated a novel type of super oscillatory lens which produces a continuous distribution of sub wavelength light localisations extending over several wavelengths along the optical axis. This 'optical needle' is also characterised by a large field of view. I have experimentally demonstrated a optical needle lens with 7um depth of focus and 16% narrower than a diffraction limited focal spot. I have characterised the point spread function of the above mentioned super oscillatory lenses, i.e. their ability to accurately image a point source. The images of the point source generated by these super oscillatory lenses are at least 24% smaller than that produced by an ideal glass lens restrained by the Abbe diffraction limit. I have experimentally verified the imaging characteristics of the optical needle lens and demonstrated its ability to detect the off axis placement of a point like source. I have developed the nano fabrication processes for manufacturing the super oscillatory lenses on thin films of metals (Au, Al, Ti) using gallium focused ion beam milling technology. The focusing characteristics of the fabricated structures showed very good agreement with computational predictions. I have computationally shown that objects placed within the field of viewfocfocus of the optical needle lens can be imaged with super resolution quality. This is a significant improvement over the sub wavelength step scanning imaging technique reported in this thesis for the other kind of super oscillatory lens. For example, a super oscillatory lens can resolve a 'random' cluster of 0.15 lambda diameter nano holes with the smallest edge to edge separation of 0.28 lambda. I have experimentally demonstrated the first prototype of a solid immersion superoscillatory lens that promises to achieve a 50 nm hotspot with 405 nm illumination for applications in heat assisted magnetic recording technology. I have demonstrated for the first time a planar diffraction grating for visible light designed by arranging meta molecules to produce a periodic phase ramp. I have also demonstrated the first ever metamaterial based planar lens array that produced a 2D array of sub wavelength foci. Finally, I have provided the first experimental evidence that photoluminescence of gold can be substantially enhanced by patterning the film with designed 2D nano structured array (or, metamaterials) When resonant two photon excitation is used the metamaterial enhances the photoluminescence by more than 76 times. I have also observed that the photoluminescence emission peaks are linked to the frequencies of absorption resonances in the metamaterials.", "author_names": [ "Tapashree Roy" ], "corpus_id": 136872029, "doc_id": "136872029", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Control and localisation of light with engineered nano structures", "venue": "", "year": 2014 } ]

[ { "abstract": "In recent years, semiconductor photocatalytic process has shown a great potential as a low cost, environmental friendly and sustainable treatment technology to align with the \"zero\" waste scheme in the water/wastewater industry. The ability of this advanced oxidation technology has been widely demonstrated to remove persistent organic compounds and microorganisms in water. At present, the main technical barriers that impede its commercialisation remained on the post recovery of the catalyst particles after water treatment. This paper reviews the recent R&D progresses of engineered photocatalysts, photoreactor systems, and the process optimizations and modellings of the photooxidation processes for water treatment. A number of potential and commercial photocatalytic reactor configurations are discussed, in particular the photocatalytic membrane reactors. The effects of key photoreactor operation parameters and water quality on the photo process performances in terms of the mineralization and disinfection are assessed. For the first time, we describe how to utilize a multi variables optimization approach to determine the optimum operation parameters so as to enhance process performance and photooxidation efficiency. Both photomineralization and photo disinfection kinetics and their modellings associated with the photocatalytic water treatment process are detailed. A brief discussion on the life cycle assessment for retrofitting the photocatalytic technology as an alternative waste treatment process is presented. This paper will deliver a scientific and technical overview and useful information to scientists and engineers who work in this field.", "author_names": [ "Meng Nan Chong", "Bo Jin", "Christopher W K Chow", "Christopher P Saint" ], "corpus_id": 11490118, "doc_id": "11490118", "n_citations": 3562, "n_key_citations": 105, "score": 1, "title": "Recent developments in photocatalytic water treatment technology: a review.", "venue": "Water research", "year": 2010 }, { "abstract": "Visible light responsive photocatalytic technology holds great potential in water treatment to enhance purification efficiency, as well as to augment water supply through the safe usage of unconventional water sources. This review summarizes the recent progress in the design and fabrication of visible light responsive photocatalysts via various synthetic strategies, including the modification of traditional photocatalysts by doping, dye sensitization, or by forming a heterostructure, coupled with p conjugated architecture, as well as the great efforts made within the exploration of novel visible light responsive photocatalysts. Background information on the fundamentals of heterogeneous photocatalysis, the pathways of visible light responsive photocatalysis, and the unique features of visible light responsive photocatalysts are presented. The photocatalytic properties of the resulting visible light responsive photocatalysts are also covered in relation to the water treatment, i.e. regarding the photocatalytic degradation of organic compounds and inorganic pollutants, as well as photocatalytic disinfection. Finally, this review concludes with a summary and perspectives on the current challenges faced and new directions in this emerging area of research.", "author_names": [ "Shuying Dong", "Jing-lan Feng", "Maohong Fan", "Yunqing Pi", "Limin Hu", "Xiao Han", "Menglin Liu", "Jingyu Sun", "Jianhui Sun" ], "corpus_id": 94857280, "doc_id": "94857280", "n_citations": 579, "n_key_citations": 1, "score": 0, "title": "Recent developments in heterogeneous photocatalytic water treatment using visible light responsive photocatalysts: a review", "venue": "", "year": 2015 }, { "abstract": "The presence of both organic and inorganic pollutants in water due to industrial, agricultural, and domestic activities has led to the global need for the development of new, improved, and advanced but effective technologies to effectively address the challenges of water quality. It is therefore necessary to develop a technology which would completely remove contaminants from contaminated waters. TiO2 (titania) nanocatalysts have a proven potential to treat \"difficult to remove\" contaminants and thus are expected to play an important role in the remediation of environmental and pollution challenges. Titania nanoparticles are intended to be both supplementary and complementary to the present water treatment technologies through the destruction or transformation of hazardous chemical wastes to innocuous end products, that is, CO2 and H2O. This paper therefore explores and summarizes recent efforts in the area of titania nanoparticle synthesis, modifications, and application of titania nanoparticles for water treatment purposes.", "author_names": [ "Mphilisi M Mahlambi", "Catherine Jane Ngila", "Bhekie B Mamba" ], "corpus_id": 54670538, "doc_id": "54670538", "n_citations": 135, "n_key_citations": 0, "score": 0, "title": "Recent developments in environmental photocatalytic degradation of organic pollutants: the case of titanium dioxide nanoparticles a review", "venue": "", "year": 2015 }, { "abstract": "Geosmin and 2 methylisoborneol (MIB) are two taste and odour causing compounds commonly encountered in drinking water. The analytical identification and quantification of these important taste and odour compounds is required since they affect the organoleptic properties of drinking water and therefore the consumer perception and acceptability of drinking water. This thesis provides an up to date summary of analytical techniques for their identification and quantification. Furthermore, recent developments in the elimination of these target compounds are overviewed; conventional treatment methods such as coagulation, sedimentation, filtration and chlorination are ineffective and alternative successful methods are being sought. There is potential for new elimination technology to be implemented into water treatment facilities due to consumer demand. TiO2 thin films were produced from a magnetron sputtering technique, along with N TiO2, Mo TiO2 and Er TiO2. All The films were characterised in terms of structure and composition using Scanning electron microscopy (SEM) Raman spectroscopy, X ray diffraction (XRD) ultraviolet visible spectroscopy (UV Vis) X ray photoelectron spectroscopy (XPS) energy dispersive X ray spectroscopy (EDX) and surface profilometry. Nitrogen doped titania (N TiO2) photocatalytic thin films were prepared by reactive magnetron sputter deposition. Nitrogen doping was achieved by the introduction of nitrogen gas as an additional reactive gas during sputtering. There was a distinctive shift of the absorption band in the N TiO2 to longer visible regions of the electromagnetic spectrum. The photocatalytic performance was evaluated by mineralisation of geosmin and MIB. XPS revealed that 1% nitrogen doping resulted in reduction of the band gap energy, enabling 80% degradation of geosmin and MIB under visible light irradiation in 150 minutes. Titanium dioxide nanoparticles and titanium dioxide nanoparticles doped with nitrogen were produced via a sol gel method for direct comparison with the thin films to break down the T&Os, unfortunately many issues arise with using nanoparticles in drinking water treatment as the nanoparticles can leach into the water. A series of erbia doped titania (Er TiO2) thin films photocatalysts were also deposited by powder magnetron sputtering method, this material has never been produced before. Erbia powder precursor ranging from 5 to 12.5 were used to dope the titania films. The amount of erbia present in the TiO2 thin film was determined using inductively coupled plasma mass spectrophotometry (ICP MS) Raman spectroscopy showed that the films were not crystalline and the broad peak positions obtained corresponded to a mixture of anatase and brookite crystalline forms. XPS analysis revealed that erbium was present in the form of an oxide. The experiments demonstrated that geosmin and 2 MIB in aqueous solutions was successfully degraded under visible light 450 nm) using Er TiO2. The results demonstrate successful degradation of geosmin and MIB. These results show the feasibility of utilising the magnetron sputtering technique to grow films for industrial applications in new solar powered elimination technology for implementation in water treatment facilities.", "author_names": [ "H Casey" ], "corpus_id": 103469779, "doc_id": "103469779", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Visible light induced photocatalytic decomposition of odorant compounds in drinking water", "venue": "", "year": 2017 }, { "abstract": "The technology of photocatalytic oxidation in protecting the environment has been one of the focuses in the world.The recent developments of TiO2 photocatalyst in the field of polluted water treatment are reviewed systematically in this paper.Immobilization technology of TiO2 photocatalyst and new type photocatalytic reactor are also summarized.", "author_names": [ "Liu Qingju" ], "corpus_id": 204278645, "doc_id": "204278645", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Development of TiO_2 Photocatalyst in Polluted Water Treatment", "venue": "", "year": 2007 }, { "abstract": "Abstract TiO2 based photocatalysis has become a viable technology in various application fields such as (waste)water purification, photovoltaics/artificial photosynthesis, environmentally friendly organic synthesis and remediation of air pollution. Because of the increasing impact of bad air quality worldwide, this review focuses on the use and optimization of TiO2 based photocatalysts for gas phase applications. Over the past years various specific aspects of TiO2 photocatalysis have been reviewed individually. The intent of this review is to offer a broad tutorial on (recent) trends in TiO2 photocatalyst modification for the intensification of photocatalytic air treatment. After briefly introducing the fundamentals of photocatalysis, TiO2 photocatalyst modification is discussed both on a morphological and an electronic level from the perspective of gas phase applications. The main focus is laid on recent developments, but also possible opportunities to the field. This review is intended as a solid introduction for researchers new to the field, as well as a summarizing update for established investigators.", "author_names": [ "Sammy W Verbruggen" ], "corpus_id": 94409911, "doc_id": "94409911", "n_citations": 171, "n_key_citations": 2, "score": 0, "title": "TiO2 photocatalysis for the degradation of pollutants in gas phase: From morphological design to plasmonic enhancement", "venue": "", "year": 2015 }, { "abstract": "Abstract Heterogeneous photocatalysis is a versatile, low cost, and environmentally benign treatment technology for a host of pollutants. This chapter considers recent developments in the research and application of heterogeneous photocatalysis for (1) water treatment, (2) air depollution, (3) hydrogen production, (4) hydrocarbon generation, (5) transformation of specific compounds, and (6) applications in construction, as well as in (7) photodynamic therapy. It also deals with photoelectrocatalysts for solar energy conversion and coupling of heterogeneous photocatalysis with other Advanced Oxidation Processes (AOPs) Techniques in photocatalyst powder immobilization and the main factors that affect the photocatalytic process are also described. Finally, a reactor design for photocatalytic application is proposed and prospects for all processes are discussed with the goal of overcoming challenges and stimulating further research into this promising field. Different types of photoreactors are described in relation to their applications.", "author_names": [ "Beata Bajorowicz", "Marek P Kobylanski", "Anna Malankowska", "Pawel Mazierski", "Joanna Nadolna", "Aleksandra Pieczynska", "Adriana Zaleska-Medynska" ], "corpus_id": 103886060, "doc_id": "103886060", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Application of metal oxide based photocatalysis", "venue": "", "year": 2018 }, { "abstract": "A light source and a semiconducting material comprise a powerful duo that may offer several photocatalytic applications for environmental remediation; in recent years, photocatalytic disinfection based on sunlight has gained considerable attention as an efficient and sustainable technology to control the population of various microorganisms in several aqueous matrices. This chapter highlights recent developments in the field both from an engineering and a microbiological point of view. Advances in photocatalytic materials include the modification of all time classic titania to perform better in the visible part of the electromagnetic spectrum, as well as synthesize novel catalysts such as silver phosphate or robust Fenton like materials. Measuring disinfection efficiency correctly is critical in designing proper treatment systems. Disinfection kinetics are affected by several factors including reactor configuration, the water matrix, possible synergy with other oxidation processes, the selection of the test microorganism, and, most importantly, the way the population of microorganisms is measured; the latter is crucial since disinfection efficiency can easily be overestimated. All these, alongside the mechanisms of microbial structure destruction upon photocatalytic illumination and the perspectives and constraints of process scale up, are dealt with in this chapter.", "author_names": [ "Danae Venieri", "Dionissios Mantzavinos" ], "corpus_id": 132038453, "doc_id": "132038453", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Disinfection of Waters/Wastewaters by Solar Photocatalysis", "venue": "", "year": 2017 }, { "abstract": "Nano sized TiO2 photocatalytic water splitting technology has great potential for low cost, environmentally friendly solar hydrogen production to support the future hydrogen economy. Presently, the solar to hydrogen energy conversion efficiency is too low for the technology to be economically sound. The main barriers are the rapid recombination of photo generated electron/hole pairs as well as backward reaction and the poor activation of TiO2 by visible light. In response to these deficiencies, many investigators have been conducting research with an emphasis on effective remediation methods. Some investigators studied the effects of addition of sacrificial reagents and carbonate salts to prohibit rapid recombination of electron/hole pairs and backward reactions. Other research focused on the enhancement of photocatalysis by modification of TiO2 by means of metal loading, metal ion doping, dye sensitization, composite semiconductor, anion doping and metal ion implantation. This paper aims to review the up to date development of the above mentioned technologies applied to TiO2 photocatalytic hydrogen production. Based on the studies reported in the literature, metal ion implantation and dye sensitization are very effective methods to extend the activating spectrum to the visible range. Therefore, they play an important role in the development of efficient photocatalytic hydrogen production.", "author_names": [ "Meng Ni", "Michael K H Leung", "Dennis Yiu Cheong Leung", "K Sumathy" ], "corpus_id": 93782298, "doc_id": "93782298", "n_citations": 3240, "n_key_citations": 24, "score": 0, "title": "A review and recent developments in photocatalytic water splitting using TiO2 for hydrogen production", "venue": "", "year": 2007 }, { "abstract": "", "author_names": [ "S Pandey", "Kotesh Kumar Mandari", "Joonwoo Kim", "Misook Kang", "Elvis Fosso-Kankeu" ], "corpus_id": 219435882, "doc_id": "219435882", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Recent Advancement in Visible Light Responsive Photocatalysts in Heterogeneous Photocatalytic Water Treatment Technology", "venue": "", "year": 2020 } ]

[ { "abstract": "Terahertz time domain spectroscopy is used to probe the electromagnetic properties of metamaterials, which are dynamically photoexcited, using synchronized femtosecond near infrared laser pulses. Blueshift tunability of the electric dipole metamaterial's resonance, as well as a broadband phase tunability reaching ~p/4, are demonstrated. Numerical simulations show the observations are due to changes in the complex index of the photoexcited semiconductor substrate.", "author_names": [ "J-M Manceau", "Nian-Hai Shen", "Maria Kafesaki", "Costas M Soukoulis", "Stylianos Tzortzakis" ], "corpus_id": 54763084, "doc_id": "54763084", "n_citations": 67, "n_key_citations": 2, "score": 0, "title": "Dynamic response of metamaterials in the terahertz regime: Blueshift tunability and broadband phase modulation", "venue": "", "year": 2010 }, { "abstract": "A deployment scale array of locally resonant membrane type acoustic metamaterials (MAMs) is fabricated. The acoustic performance of the array is measured in a transmission loss chamber, and a complex interaction between the individual cell and the array length scales is shown to exist. Transmission behavior of both the membrane and the array are independently studied using analytical models, and a method for estimating transmission loss through the structure that combines vibroacoustic predictions from both length scales is presented and shown to agree with measurements. Degradation of transmission loss performance often associated with scaling individual MAM cells into arrays is explained using analytical tools and verified using laser vibrometry. A novel design for hierarchical locally resonant acoustic metamaterials is introduced, and experimental and analytical data confirm this approach offers an effective strategy for minimizing or eliminating the efficiency losses associated with scaling MAM structures. [DOI: 10.1115/1.4045789]", "author_names": [ "William Thomas Edwards", "Chia-Ming Chang", "Geoffrey P McKnight", "Adam E Sorensen", "Steven R Nutt" ], "corpus_id": 212906197, "doc_id": "212906197", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Transmission Loss and Dynamic Response of Hierarchical Membrane Type Acoustic Metamaterials", "venue": "", "year": 2020 }, { "abstract": "Membrane type acoustic metamaterials were fabricated, characterized, and analyzed to understand their acoustic response. Thin plates which obey the acoustic mass law have low transmission loss (TL) at low frequencies. Acoustic metamaterials with negative dynamic mass density have been shown to demonstrate a significant (5x) increase in TL over mass law predictions for a narrow band (100 Hz) at low frequencies (100 1000 Hz) The peak TL frequency can be tuned to specific values by varying the membrane and mass properties. In this work, TL magnitude as a function of frequency was measured for variations in the mass magnitude and membrane tension using an impedance tube setup. The dynamic properties of membranes constructed from different materials were measured and compared to the results of coupled field acoustic structural finite element analysis modeling to understand the role of tension and element quality factor. To better comprehend the mechanism(s) responsible for the TL peak, a laser vibrometer was", "author_names": [ "Christina J Naify", "Chia-Ming Chang", "Geoffrey P McKnight", "Steven R Nutt" ], "corpus_id": 121459567, "doc_id": "121459567", "n_citations": 150, "n_key_citations": 0, "score": 0, "title": "Transmission loss and dynamic response of membrane type locally resonant acoustic metamaterials", "venue": "", "year": 2010 }, { "abstract": "This paper presents full scale modeling and nonlinear dynamic analysis of sandwich plates with auxetic 3D lattice core, which is further designed to possess three functionally graded (FG) configurations through the plate thickness direction for the first time. The effective Poisson's ratio (EPR) and fundamental frequencies of auxetic 3D lattice metamaterials are analyzed and verified by static and vibration tests using specimens fabricated by 3D printing. Considering the large deflection nonlinearity of sandwich plates and the accompanying changes in effective properties of lattice microstructures, full scale FE modeling and nonlinear dynamic thermal mechanical analysis are performed, with material properties assumed to be temperature dependent. Numerical results revealed that the auxetic core can significantly reduce the dynamic deflections, in comparison with its counterpart with positive EPR. Furthermore, FG configurations have distinct effects on the natural frequencies and dynamic deflection time curves of sandwich plates, along with EPR deflection curves in the large deflection region.", "author_names": [ "Chong Li", "Hui-shen Shen", "Hai Wang" ], "corpus_id": 219736121, "doc_id": "219736121", "n_citations": 13, "n_key_citations": 0, "score": 1, "title": "Nonlinear dynamic response of sandwich plates with functionally graded auxetic 3D lattice core", "venue": "", "year": 2020 }, { "abstract": "The amplitude dependent dynamic response in acoustic metamaterials having nonlinear local oscillator microstructures is studied using numerical simulations on representative discrete mass spring models. Both cubically nonlinear hardening and softening local oscillator cases are considered. Single frequency, bi frequency, and wave packet excitations at low and high amplitude levels were used to interrogate the models. The propagation and attenuation characteristics of harmonic waves in a tunable frequency range is found to correspond to the amplitude and nonlinearity dependent shifts in the local resonance bandgap for such nonlinear acoustic metamaterials. A predominant shift in the propagated wave spectrum towards lower frequencies is observed. Moreover, the feasibility of amplitude and frequency dependent selective filtering of composite signals consisting of individual frequency components which fall within propagating or attenuating regimes is demonstrated. Further enrichment of these wave manipulation mechanisms in acoustic metamaterials using different combinations of nonlinear microstructures presents device implications for acoustic filters and waveguides.", "author_names": [ "James M Manimala", "C T Sun" ], "corpus_id": 11948593, "doc_id": "11948593", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "Numerical investigation of amplitude dependent dynamic response in acoustic metamaterials with nonlinear oscillators.", "venue": "The Journal of the Acoustical Society of America", "year": 2016 }, { "abstract": "Architected materials have facilitated a significant breakthrough in the control of the mechanical behavior of structures. Most notably, metamaterials with unprecedented properties can be easily designed in large scales, exhibiting high strength, tunability of their properties, resilience or versatility to large deformations, and auxetic behavior. In addition, 4D printed structures can modify their shape depending on the working environment. Due to their chemical composition, these structures can modify their mechanical and electrochemical properties based on external stimuli. This mechanism has substantial implications on the mechanical response of the material, furnishing stiffening of the structure or malleability on demand. Furthermore, designing structures that are also adaptive to actuation has given rise to the design of flexible 3D printed mechanisms. Flexible structures can be utilized for engineering applications requiring large but recoverable deformations, continuous motion, and high precision. A characteristic category of structures encompassing these properties are soft robotics. Soft robotic mechanisms are composed of rubber materials that can be electrically actuated to sustain nonlinear deformations. Combining these designs with much stronger fiber components leads to the design of artificial muscles, imitating animal motion and having a significantly higher strength than simple soft robot systems. Nevertheless, metamaterials also exhibit remarkable properties that are not observed in conventional systems. A characteristic example is the transport of mechanical signals with the proclivity to a specific direction. This has been accomplished through the design of nonreciprocal mechanical metamaterials. In regular materials, the transmission of any physical quantity, such as mechanical signals or mechanical waves, is identical, regardless of geometrical or material asymmetries and defects between any two points in space. However, nonreciprocal metamaterials can alter this behavior, giving directionality to the transport of these mechanical quantities. This is the paragon of the next generation mechanical signal transport, isolation, and energy storage. In addition, the combination of the architected design with the macroscopic dynamic loading conditions can provide the formation of distinct elastic vector solitons. These coupled waves can have significantly different formations depending on the direction of the wave, controlling not only the direction of the signal, but also its shape. The inexorable advances in 3D printing technology have enabled the fabrication of these structures. Techniques such as fused deposition modeling (FDM) Z. Vangelatos, Z. Zhang, Prof. G. X. Gu, Prof. C. P. Grigoropoulos Department of Mechanical Engineering University of California, Berkeley Berkeley, CA 94720, USA E mail: zacharias_vangelatos@berkeley.edu; zz_zhang@berkeley.edu; ggu@berkeley.edu; cgrigoro@berkeley.edu Z. Vangelatos, Prof. C. P. Grigoropoulos Department of Mechanical Engineering Laser Thermal Laboratory University of California, Berkeley Berkeley, CA 94720, USA Z. Zhang, Prof. G. X. Gu Gu Research Group Department of Mechanical Engineering University of California, Berkeley Berkeley, CA 94720, USA", "author_names": [ "Zacharias Vangelatos", "Zhizhou Zhang", "Grace X Gu", "Costas P Grigoropoulos" ], "corpus_id": 216277082, "doc_id": "216277082", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Tailoring the Dynamic Actuation of 3D Printed Mechanical Metamaterials through Inherent and Extrinsic Instabilities", "venue": "", "year": 2020 }, { "abstract": "Simulation data are presented for identifying and analysing the dynamic properties of the rainbow metamaterials as presented in the articles \"Rainbow metamaterials for broadband multi frequency vibration attenuation: numerical analysis and experimental validation\" (Meng et al. 2019 [1] and \"Optimal design of rainbow elastic metamaterials\" (Meng et al. 2019 [2] In this data article, the frequency response functions and mode shapes of the rainbow metamaterials are numerically calculated by Finite Element models set up in Ansys Mechanical APDL. Harmonic analysis was performed to figure out the receptance function values of the rainbow metamaterials within the frequency regime 0 500 Hz. Modal analysis was applied to estimate the mode shapes, which could be used to explain the critical peaks and dips in the receptance function curve. Source files of Finite Element models are provided in the data. The Finite Element simulation is not only an effective alternative way to estimate the dynamic properties of the rainbow metamaterials, the mode shape analysis, which is unlikely to be achieved with the analytical model, provides direct insights into the underlying vibration mechanism of the rainbow metamaterials.", "author_names": [ "Han Meng", "Dimitrios Chronopoulos", "Adriano Todorovic Fabro" ], "corpus_id": 209445472, "doc_id": "209445472", "n_citations": 7, "n_key_citations": 0, "score": 1, "title": "Numerical simulation data for the dynamic properties of rainbow metamaterials", "venue": "Data in brief", "year": 2020 }, { "abstract": "Microstructured materials, namely metamaterials, are one of the most relevant topics of the recent period due to their interdisciplinary nature. Driven by their wide range of applications, we provide an overview of a class of elastic solids which embed dynamic microstructures capable of trapping energy when subject to dynamic loads. Based on the recently developed modeling approaches, we show several applications related to wave cloaking, filtering and also multi structured surfaces, often referred to as meta surfaces. These culminate in the analysis of a practical example, based on a real life recent seismic event induced by a hydrofracture exploration. The latter shows the viability of the vibration analysis in the assessment of the seismic response, and also the role of meta surfaces as localisers of vibrations, e.g. suggesting non periodic earthquake tolerant design strategies of housing estates.", "author_names": [ "Ariadna Yakovleva", "Igor Borisovich Movchan", "Diego Misseroni", "Nicola Maria Pugno", "Alexander B Movchan" ], "corpus_id": 232210653, "doc_id": "232210653", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Multi Physics of Dynamic Elastic Metamaterials and Earthquake Systems", "venue": "Frontiers in Materials", "year": 2020 }, { "abstract": "Perfect state transfer of the bus topological system enables the sharing of information or excitation between nodes. Herein we report groundbreaking research on the transfer of the graphene bridged bus topological network structure to an electromagnetic metamaterial setting, named \"bus topological network metamaterials (TNMMs)\" Correspondingly, the electromagnetic response imprints onto the topological excitation. We find that the bus TNMMs display a perfect modulation of the terahertz response. The blue shift of resonance frequency could increase to as large as 1075 GHz. The modulation sensitivity of the bus TNMMs reaches 1027 GHz/Fermi level unit (FLU) Meanwhile, with the enhancement of modulation, the line shape of the reflection keeps underformed. Parabola, ExpDec1, and Asymptotic models are used to estimate the modulation of the resonance frequency. Besides, the bus TNMMs system provides a fascinating platform for dynamic cloaking. By governing the Fermi level of graphene, the bus TNMMs can decide whether it is cloaking or not in a bandwidth of 500 GHz. Also, the bus TNMMs exhibit the immense potential for dynamically detecting the vibrational fingerprinting of an analyte. These results give a far reaching outlook for steering dynamically the terahertz response with the bus TNMMs. Therefore, we believe that the discovery of bus TNMMs will revolutionize our understanding of the modulation of the electromagnetic response.", "author_names": [ "Xin Yan", "Zhang Zhang", "Ju Gao", "Lanju Liang", "Maosheng Yang", "Xinyuan Guo", "Jianqiang Li", "Yuanpi Li", "Dequan Wei", "Mingle Wang", "Xujuan Wang", "Mingji Zong", "Yunxia Ye", "Xiaoxian Song", "Haiting Zhang", "Jianquan Yao" ], "corpus_id": 220978878, "doc_id": "220978878", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Graphene bridged topological network metamaterials with perfect modulation applied to dynamic cloaking and meta sensing.", "venue": "Optics express", "year": 2020 }, { "abstract": "Abstract The responses of Miura ori patterned metamaterials to in plane dynamic compression are studied for several scenarios, namely: compression of uniform density metamaterials at a constant velocity and impulsive loading modelled as an impact with initial velocity, and a mass impact of a metamaterial with graded density. Analytical models of the dynamic strength enhancement, impact velocity attenuation and energy absorption are proposed for materials with uniform initial density and materials with positive density gradient. Attention is paid to the influence of the material topology governed by the initial dihedral angle g0 on the dynamic response of origami based stationary blocks with equal densities. The propagation of disturbances velocity and nominal strains along the samples is analysed and it is shown that the localisation is more pronounced for small values of g0. Different from other open cell materials (e.g. foam and honeycomb) the propagation speed of the yield stress, which corresponds to the quasi static strength, is not related to the elastic properties of the metamaterial in the form of precursor elastic wave as it is governed by the inertial properties of the cells due to the local structural softening. Therefore, the in plane dynamic compression of Miura ori patterned metamaterials cannot be directly interpreted by means of the shock wave theory commonly used for cellular materials with different topologies. Nonetheless it is shown that, similarly to other cellular materials, the Miura ori patterned metamaterials exhibit increased energy absorption capacity when increasing the loading rate. However, the dynamic energy absorption capacity of the analysed metamaterials in not uniquely defined by their relative density and is strongly dependent on their topology. The analytical models are verified by numerical simulations.", "author_names": [ "Dora Karagiozova", "Jianjun Zhang", "Guoxing Lu", "Zhong You" ], "corpus_id": 139274839, "doc_id": "139274839", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "Dynamic in plane compression of Miura ori patterned metamaterials", "venue": "International Journal of Impact Engineering", "year": 2019 } ]

[ { "abstract": "Recent advances in plasma immersion ion implantation PIII are progressing at a rapid pace. PIII was originally envisioned as a conformal ion implantation technology for the surface modification of materials. PIII also offers the advantages of high dose rates, even at low energy, and single wafer implants over large areas. Such advantages are becoming very important for semiconductor manufacturing, particularly for 300 mm wafers and flat panel displays. Applications of PIII in microelectronics introduce new considerations. Conformal implantation is not required, and is unwanted in most semiconductor processes, except for trench doping type applications. In various implant applications, there are often radically different requirements of plasma physics and chemistry. For example, the formation of shallow junctions requires extremely low energy implantation, and a precise implant range may not be necessary or ideal. In this application, PIII becomes the concept of plasma doping, where a wafer under either a DC or pulse bias is directly exposed to the plasma. On the other hand, hydrogen PIII for layer transfer requires extremely precise implant ranges, straggles and sample temperature, but the exact dose may not be critical. In this paper, two important application areas that have attracted much attention and research in the past 2 years, hydrogen PIII and the fabrication of low k materials, are reviewed. Q 2001 Elsevier Science B.V. All rights reserved.", "author_names": [ "Paul K Chu", "Chung Chan" ], "corpus_id": 138080842, "doc_id": "138080842", "n_citations": 26, "n_key_citations": 0, "score": 1, "title": "Applications of plasma immersion ion implantation in microelectronics a brief review", "venue": "", "year": 2001 }, { "abstract": "Abstract Plasma immersion ion implantation and deposition (PIII&D) has been used extensively in microelectronics and metallurgical engineering and its future in biomedical engineering and nanotechnology is even brighter with many novel and burgeoning applications. In this invited review, recent work conducted in the Plasma Laboratory at City University of Hong Kong is described. Advances in direct current plasma immersion ion implantation, especially non contact printing and implantation into 3 dimensional components, are discussed. Examples of new applications include fabrication and biological properties of plasma modified titanium based materials and control of the surface degradation rate and other properties of biodegradable polymeric and metallic materials.", "author_names": [ "Paul K Chu" ], "corpus_id": 55677988, "doc_id": "55677988", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Progress in direct current plasma immersion ion implantation and recent applications of plasma immersion ion implantation and deposition", "venue": "", "year": 2013 }, { "abstract": "Abstract In the paper, plasma immersion ion implantation (PIII) has been put forward to texture and dope the silicon for solar cells. The influence of PIII parameters on the surface structure has been investigated. The various surface structure of the silicon can be obtained by PIII texturing. Compared with acid texturing solar cells, the average conversion efficiency of PIII texturing solar cells has been improved by 0.7% absolute gain. The characteristics of PN junction formed by PIII doping have been investigated. The conversion efficiency of the solar cell can reach as high as 14.84% using PIII doping.", "author_names": [ "Bang-wu Liu" ], "corpus_id": 110612387, "doc_id": "110612387", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "The Applications of Plasma Immersion Ion Implantation to Crystalline Silicon Solar Cells", "venue": "", "year": 2013 }, { "abstract": "", "author_names": [ "" ], "corpus_id": 139047306, "doc_id": "139047306", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The Applications of Plasma Immersion Ion Implantation to Crystalline Silicon Solar Cells", "venue": "", "year": 2013 }, { "abstract": "Plasma immersion ion implantation is a new ion implantation technique for surface modification of materials.The principle and advantages of PIII were analyzed and discussed systematically.Untreated materials were placed directly in a plasma source chamber.It kept in conventional beam ion implantation(CBII) specialty,circumvents the line of sight restriction of conventional beam ion implantation,overcomes the retained did problem and made implantation devices simple and inexpensive.Its applications in surface modification of metallic materials,semiconductor materials and polymer materials were reviewed,the direction of its applications and development were indicated.", "author_names": [ "Chen Hui-min" ], "corpus_id": 137851346, "doc_id": "137851346", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Application and Development of Plasma Immersion Ion Implantation in the Material Surface Modification", "venue": "", "year": 2008 }, { "abstract": "Abstract Surface processing of tools and other industrial components was carried out by Plasma Immersion Ion Implantation (PIII) for the improvement of their tribological properties and consequently to reach their prolonged lifetime. Tools made of different types of steels, mainly for the production of rivets, had their lifetime extended for up to 70 times, reducing cost and improving productivity in a mass producing line. Metallic samples used in components for prosthesis (CrNiMo) showed improvements in hardness of up to 250% after nitrogen PIII while non conducting polymer used also for prosthesis component (UHMWPE) was hardened significantly due to the formation of a DLC layer in the treated surface. Tungsten carbide tools were also nitrogen PIII processed which resulted in some improvement in their lifetime but more importantly in excellent surface finishing of the produced Ti parts for dental implants. Steel samples made from H13 alloy showed successful PIII implantation profile (up to depths of 18 mm) and improved hardness of a factor of two was obtained. These results for H13 steel point toward successful applications in molds and other industrial components.", "author_names": [ "Mario Ueda", "Luiz Angelo Berni", "Rito Mijarez Castro" ], "corpus_id": 136958266, "doc_id": "136958266", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "Application of plasma immersion ion implantation for improved performance of tools and industrial components", "venue": "", "year": 2005 }, { "abstract": "Thin film was synthesized on GB/T 1438 high speed steel substrates by Plasma Immersion Ion Implantation and Deposition(PIIID).After PIIID treatments,the as deposited samples were evaluated by SEM analysis,the microhardness and lifetime tests.The results show that the microhardness of deposited sample is over 2 000HV and the lifetime of drills prolong nearly 5 times.", "author_names": [ "Huang Rui-fen" ], "corpus_id": 138320848, "doc_id": "138320848", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Application of plasma immersion ion implantation and deposition in cutting tool", "venue": "", "year": 2010 }, { "abstract": "By means of X ray photoelectron spectroscopy (XPS) and differential scanning calorimetry (DSC) this study set out to investigate the application of plasma immersion ion implantation (PIII) for the surface modification of ProTaper NiTi rotary instruments. This study was undertaken because the PIII method was perceived to have the potential of developing into a standard surface modification technique that improves clinical quality and outcome. Specimens received nitrogen ion or nitrogen plus argon ion implantation. XPS analyses with and without argon ion etching were obtained for all specimens. In addition, DSC analysis was performed to investigate the phase transformation behavior of the bulk material. Results indicated that the surfaces of NiTi instruments were successfully modified by nitrogen PIII, whereby a light golden TiN layer was yielded. Moreover, the PIII technique did not alter the superelastic character of NiTi instruments because it was carried out at near room temperature. We thus concluded that nitrogen PIII is a promising surface modification technique to improve the surface characteristics of NiTi rotary instruments.", "author_names": [ "Uei-Ming Li", "Masahiro Iijima", "Kazuhiko Endo", "William A Brantley", "Satish B Alapati", "Chun-Pin Lin" ], "corpus_id": 8321916, "doc_id": "8321916", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Application of plasma immersion ion implantation for surface modification of nickel titanium rotary instruments.", "venue": "Dental materials journal", "year": 2007 }, { "abstract": "Abstract In this study, an effective seeding technology, plasma immersion ion implantation of palladium (PIII Pd) was proposed to achieve defect free gap filling for copper electroplating (Cu ECP) It was found that a threshold dosage ~5.2x10 18 m 2 of PIII Pd was required to drive Cu ECP and the dependence of Pd dosage on the implantation time was quasi linear. The thickness of electroplated copper films increased as the Pd dosage increased. Too high a Pd dosage caused a rough copper film with high resistivity >10 mO cm) while too low a Pd dosage resulted in an insufficient nucleation site for Cu ECP, leading to poor film adhesion. In addition, a higher substrate bias of PIII was suggested to enhance the gap filling capability of Cu ECP and the Cu(111) formation of electroplated copper films.", "author_names": [ "S Y Chiu", "Ying-Lang Wang", "Shih-Chieh Chang", "Ming Shiann Feng" ], "corpus_id": 54918648, "doc_id": "54918648", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Application of plasma immersion ion implantation on seeding copper electroplating for multilevel interconnection", "venue": "", "year": 2005 }, { "abstract": "Due to its mechanical properties and low density, the Ti 6Al 4V titanium al loy is used in hip prostheses. But the tribological behavior of Ti 6Al 4V sliding against ultra high molecular weight polyethylene involves wear degradations. The wear behavior of (Ti 6Al 4V/UHMWPE) couple can be improved by ion implantation of nitrogen. After a characterization study to find the optimal parameters for classic ion implantation, this study presents an analysis of wear behavior in comparison with chemical composition, microhardness and adhesion work for a new implantation technique, plasma immersion ion implantation.", "author_names": [ "Agnes Fabre", "Laurent Barrallier", "F Torregrosa", "Laurent Roux" ], "corpus_id": 59271255, "doc_id": "59271255", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Ion Beam Implantation and Plasma Immersion Ion Implantation. Application on Nitrided Ti 6Al 4V Titanium Alloy", "venue": "", "year": 1997 } ]

[ { "abstract": "We have performed density functional calculations using a range of local and semi local as well as hybrid density functional approximations of the structure and elastic constants of 18 semiconductors and insulators. We find that most of the approximations have a very small error in the lattice constants, of the order of 1% while the errors in the elastic constants and bulk modulus are much larger, at about 10% or better. When comparing experimental and theoretical lattice constants and bulk modulus we have included zero point phonon effects. These effects make the experimental reference lattice constants 0.019 A smaller on average while making the bulk modulus 4.3 GPa stiffer on average. According to our study, the overall best performing density functional approximations for determining the structure and elastic properties are the PBEsol functional, the two hybrid density functionals PBE0 and HSE (Heyd, Scuseria, and Ernzerhof) as well as the AM05 functional.", "author_names": [ "Mikael Rasander", "Michelle A Moram" ], "corpus_id": 12073910, "doc_id": "12073910", "n_citations": 41, "n_key_citations": 1, "score": 1, "title": "On the accuracy of commonly used density functional approximations in determining the elastic constants of insulators and semiconductors.", "venue": "The Journal of chemical physics", "year": 2015 }, { "abstract": "BACKGROUND Improved patient comfort and optimal glycemic control have led to the widespread use of insulin pens, particularly in Europe. Most of the former studies on the dose accuracy of insulin pens included only a small number of doses and pens. In extension to our previous large scale study testing the dosing accuracy following a randomized dosing sequence with each pen, the present study was more directed toward the dose accuracy for one specific dose dispensed repeatedly with the same pen. This is the first study providing detailed comparative data on the accuracy of repeated dose delivery with prefilled disposable insulin pens at low, middle, and high doses, dispensed over the entire pen volume. MATERIALS AND METHODS In total, 15 previously unused insulin pens from two lots of each pen type (SoloSTAR((r) [sanofi aventis, Paris, France] FlexPen((r) [Novo Nordisk A/S, Bagsvaerd, Denmark] Next Generation FlexPen [Novo Nordisk] and KwikPen(tm) [Eli Lilly, Indianapolis, IN] were used to deliver 5 unit (low) 30 unit (middle) and 60 unit (high) doses, respectively, dispensed four times from each pen in a nonrandomized manner. Actual doses were determined gravimetrically taking the density of the respective insulin into account and were evaluated according to the guidelines (DIN EN ISO 11608 1:2000) of the International Organization for Standardization (ISO) RESULTS All tested insulin pens met the requirements for accuracy with none of the single values being outside the defined range of the ISO recommendations (1+ 1 units, 30+ 1.5 units, and 60+ 3 units, respectively) CONCLUSION The present study demonstrated a consistent and accurate dose delivery at all dosage levels for all tested insulin pens, with no clinically relevant differences among the products.", "author_names": [ "Meike Krzywon", "Thomas van der Burg", "Uwe Fuhr", "Manfred Schubert-Zsilavecz", "Mona Abdel-Tawab" ], "corpus_id": 25948019, "doc_id": "25948019", "n_citations": 25, "n_key_citations": 0, "score": 0, "title": "Study on the dosing accuracy of commonly used disposable insulin pens.", "venue": "Diabetes technology therapeutics", "year": 2012 }, { "abstract": "Abstract Objective: The present study aimed to assess the dosing accuracy of commonly used disposable insulin pens including SoloStar (SR) FlexPen (FP) Next Generation FlexPen (NGFP) and KwikPen (KP) It is the first comparative study covering the whole dosing range from 1 U to 60 U. It also covers the accuracy of SR at 80 U. SoloStar (SR) is a registered trademark of sanofi aventis. FlexPen (FP) and Next Generation FlexPen (NGFP) are registered trademarks of Novo Nordisk A/S. KwikPen (KP) is a registered trademark of Eli Lilly. Research design and method: A total of sixty insulin pens from two lots of each pen type were used. From each pen 1 U, 10 U, 30 U, 40 U, 60 U and 80 U were dispensed in random order. The 80 U dose was only evaluated for the SR as the other insulin pens do not deliver this dose in one injection. The actual doses were determined gravimetrically taking density of the different insulin preparations into account. The evaluation of dose accuracy was based on the regulations of the International Organization for Standardization (DIN EN ISO 11608 1:2000) Results: All tested insulin pens met the requirements for accuracy with none of the single values at all dose levels being outside the defined range of the ISO recommendations (1 1 U, 10 1 U, 30 1.5 U, 40 2 U, 60 3 U and 80 4 U) For the investigated dosage levels the absolute average deviation of all insulin pens ranged between 0.09 and 0.81 U. Conclusion: The present study demonstrates an excellent dosing accuracy for all tested insulin pens, with no clinically relevant differences between the products.", "author_names": [ "Meike Krzywon", "Mona Abdel-Tawab", "Thomas van der Burg", "Uwe Fuhr", "Manfred Schubert-Zsilavecz" ], "corpus_id": 206964955, "doc_id": "206964955", "n_citations": 17, "n_key_citations": 2, "score": 0, "title": "Dosing accuracy of commonly used disposable insulin pens", "venue": "Current medical research and opinion", "year": 2010 }, { "abstract": "Importance Accurate long term breast cancer risk assessment for women attending routine screening could help reduce the disease burden and intervention associated harms by personalizing screening recommendations and preventive interventions. Objective To report the accuracy of risk assessment for breast cancer during a period of 19 years. Design, Setting, and Participants This cohort study of the Kaiser Permanente Washington breast imaging registry included women without previous breast cancer, aged 40 to 73 years, who attended screening from January 1, 1996, through December 31, 2013. Follow up was completed on December 31, 2014, and data were analyzed from March 2, 2016, through November 13, 2017. Exposures Risk factors from a questionnaire and breast density from the Breast Imaging and Reporting Data System at entry; primary risk was assessed using the Tyrer Cuzick model. Main Outcomes and Measures Incidence of invasive breast cancer was estimated with and without breast density. Follow up began 6 months after the entry mammogram and extended to the earliest diagnosis of invasive breast cancer, censoring at 75 years of age, 2014, diagnosis of ductal carcinoma in situ, death, or health plan disenrollment. Observed divided by expected (O/E) numbers of cancer cases were compared using exact Poisson 95% CIs. Hazard ratios for the top decile of 10 year risk relative to the middle 80% of the study population were estimated. Constancy of relative risk calibration during follow up was tested using a time dependent proportional hazards effect. Results In this cohort study of 132 139 women (median age at entry, 50 years; interquartile range, 44 58 years) 2699 invasive breast cancers were subsequently diagnosed after a median 5.2 years of follow up (interquartile range, 2.4 11.1 years; maximum follow up, 19 years; annual incidence rate [IR] per 1000 women, 2.9) Observed number of cancer diagnoses was close to the expected number (O/E for the Tyrer Cuzick model, 1.02 [95% CI, 0.98 1.06] O/E for the Tyrer Cuzick model with density, 0.98 [95% CI, 0.94 1.02] The Tyrer Cuzick model estimated 2554 women (1.9% to be at high risk (10 year risk of =8% of whom 147 subsequently developed invasive breast cancer (O/E, 0.79; 95% CI, 0.67 0.93; IR per 1000 women, 8.7) The Tyrer Cuzick model with density estimated more women to be at high risk (4645 [3.5% 273 cancers [10.1% O/E, 0.78; 95% CI, 0.69 0.88; IR per 1000 women, 9.2) The hazard ratio for the highest risk decile compared with the middle 80% was 2.22 (95% CI, 2.02 2.45) for the Tyrer Cuzick model and 2.55 (95% CI, 2.33 2.80) for the Tyrer Cuzick model with density. Little evidence was found for a decrease in relative risk calibration throughout follow up for the Tyrer Cuzick model (age adjusted slope, 0.003; 95% CI, 0.018 to 0.012) or the Tyrer Cuzick model with density (age adjusted slope, 0.008; 95% CI, 0.020 to 0.004) Conclusions and Relevance Breast cancer risk assessment combining classic risk factors with mammographic density may provide useful data for 10 years or more and could be used to guide long term, systematic, risk adapted screening and prevention strategies.", "author_names": [ "Adam R Brentnall", "Jack M Cuzick", "Diana S M Buist", "Erin J Aiello Bowles" ], "corpus_id": 4616368, "doc_id": "4616368", "n_citations": 88, "n_key_citations": 2, "score": 0, "title": "Long term Accuracy of Breast Cancer Risk Assessment Combining Classic Risk Factors and Breast Density", "venue": "JAMA oncology", "year": 2018 }, { "abstract": "We perform extensive benchmark comparisons of surface hopping dynamics with numerically exact calculations for the spin boson model over a wide range of energetic and coupling parameters as well as temperature. We find that deviations from golden rule scaling in the Marcus regime are generally small and depend sensitively on the energetic bias between electronic states. Fewest switches surface hopping (FSSH) is found to be surprisingly accurate over a large swath of parameter space. The inclusion of decoherence corrections via the augmented FSSH algorithm improves the accuracy of dynamical behavior compared to exact simulations, but the effects are generally not dramatic, at least for the case of an environment modeled with the commonly used Debye spectral density.", "author_names": [ "Hsing-Ta Chen", "David R Reichman" ], "corpus_id": 20773711, "doc_id": "20773711", "n_citations": 28, "n_key_citations": 0, "score": 0, "title": "On the accuracy of surface hopping dynamics in condensed phase non adiabatic problems.", "venue": "The Journal of chemical physics", "year": 2016 }, { "abstract": "Abstract Background An accurate model to stratify breast cancer risk is required to move from a one size fits all screening paradigm to more personalised risk based screening strategies. Most risk models have limited accuracy and have been calibrated for white women. Considering the rapid increase in breast cancer incidence in China, in this study we aimed to develop a breast cancer model for Chinese women. Methods We recruited women from Fudan University Shanghai Cancer Centre. Information about their height, weight, body mass index, age at menarche, age at first delivery, age at menopause, menopause status, parity history, number of children, breastfeeding history, personal history of breast cancer, family history of breast cancer, and degree of consanguinity was obtained. Mammograms were acquired from all recruited women. We used AutoDensity software to segment the mammographic dense area. To ensure that the breast density had not been affected by presence of the lesion, we measured the mammographic breast density of patients with cancer from the cancer free breast contralateral to the biopsy proven cancer. The breast area, dense area, percentage density, and demographic variables were input into an ensemble of 50 decision trees, the results of which we combined using a hybrid sampling and boosting algorithm (RUSBoost) The variables were also fed into the logistic and stepwise logistic regression models, which are two commonly used linear models. Leave one out cross validation was used to assess the performance of the models and the receiver operating characteristics (ROC) curves were generated for each model. Findings In total, 1079 women (85 women with biopsy proven breast cancer and 994 women without breast cancer) were recruited. The classifier had an area under ROC curve (AUC) of 0*86 (95% CI 0*82 0*89) for classifying the cases as normal or high risk. It outperformed the accuracy of traditionally employed logistic and stepwise logistic regression models, which resulted in AUC values of 0*739 (0*67 0*81) and 0*757 (0*69 0*81) respectively. Interpretation When compared with linear models, use of a machine learning approach, which models data non linearity, could lead to improvement in the accuracy of a breast cancer risk stratification model. Such a model can be used to recommend intensified surveillance for women at a high risk of future breast cancer. Funding None.", "author_names": [ "Ziba Gandomkar", "Tong Li", "Zhi-Ming Shao", "L Tang", "Qin Xiao", "Yajia Gu", "Gen-Hong Di", "Claudia R Mello-Thoms", "Patrick C Brennan" ], "corpus_id": 204775794, "doc_id": "204775794", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A machine learning approach for stratifying breast cancer risk in Chinese women on the basis of epidemiological factors and mammographic density", "venue": "The Lancet", "year": 2019 }, { "abstract": "Significance Numerous empirical studies in population genetics have used a summary statistic called the sample frequency spectrum (SFS) which summarizes the information in a sample of DNA sequences. Despite their popularity, the accuracy of inference methods based on the SFS is difficult to characterize theoretically, and it is currently unknown how the estimation accuracy improves as more sites in the genome are used. Here, we establish information theoretic limits on the accuracy of all estimators that use the SFS to infer population size histories. We study the rate of convergence to the true answer as the amount of data increases, and obtain the surprising result that it is exponentially worse than known convergence rates for many classical estimation problems in statistics. The sample frequency spectrum (SFS) of DNA sequences from a collection of individuals is a summary statistic that is commonly used for parametric inference in population genetics. Despite the popularity of SFS based inference methods, little is currently known about the information theoretic limit on the estimation accuracy as a function of sample size. Here, we show that using the SFS to estimate the size history of a population has a minimax error of at least O(1/log s) where s is the number of independent segregating sites used in the analysis. This rate is exponentially worse than known convergence rates for many classical estimation problems in statistics. Another surprising aspect of our theoretical bound is that it does not depend on the dimension of the SFS, which is related to the number of sampled individuals. This means that, for a fixed number s of segregating sites considered, using more individuals does not help to reduce the minimax error bound. Our result pertains to populations that have experienced a bottleneck, and we argue that it can be expected to apply to many populations in nature.", "author_names": [ "Jonathan Terhorst", "Yun S Song" ], "corpus_id": 8506138, "doc_id": "8506138", "n_citations": 72, "n_key_citations": 1, "score": 0, "title": "Fundamental limits on the accuracy of demographic inference based on the sample frequency spectrum", "venue": "Proceedings of the National Academy of Sciences", "year": 2015 }, { "abstract": "Integral equation theories provide an efficient route for computing the solvation free energy (SFE) of molecular systems in water. The accuracy of those theories is usually tested against small molecules via comparison of SFE with reference data. However, tests against larger molecules in the nanometer regime are scarce in literature despite recent applications to such systems. Here, we thus study the accuracy and validity of a commonly used integral equation theory, namely, a three dimensional reference interaction site model (3D RISM) by considering the following problems: (1) solvation of a small to large Lennard Jones particle, (2) binding of planar hydrophobic systems with varying size and hydrophobicity, and (3) self assembly of amphiphilic molecules into a nanocapsule. The energy representation method is also utilized for comparison. The results show that the 3D RISM method works successfully for small molecules, while the accuracy degrades systematically with system size and hydrophobicity. The size dependent error in SFE does not cancel adequately between two solute configurations, resulting in a substantial error in the free energy difference. It is also shown that the free energy profiles for hydrophobic association exhibit a fictitious high energy barrier, suggesting that care must be taken for studying such systems. The numerical difficulties observed above are discussed based on the relation between hypernetted chain approximation, classical density functional theory with quadratic expansion, and the size dependent error arising from the cavity region of the system.", "author_names": [ "Takatoshi Fujita", "Takeshi Yamamoto" ], "corpus_id": 25953287, "doc_id": "25953287", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Assessing the accuracy of integral equation theories for nano sized hydrophobic solutes in water.", "venue": "The Journal of chemical physics", "year": 2017 }, { "abstract": "We have investigated the suitability of Time Dependent Density Functional Theory (TD DFT) to describe vertical low energy excitations in naked and hydrated titanium dioxide nanoparticles. Specifically, we compared TD DFT results obtained using different exchange correlation (XC) potentials with those calculated using Equation of Motion Coupled Cluster (EOM CC) quantum chemistry methods. We demonstrate that TD DFT calculations with commonly used XC potentials (e.g. B3LYP) and EOM CC methods give qualitatively similar results for most TiO2 nanoparticles investigated. More importantly, however, we also show that, for a significant subset of structures, TD DFT gives qualitatively different results depending upon the XC potential used and that only TD CAM B3LYP and TD BHLYP calculations yield results that are consistent with those obtained using EOM CC theory. Moreover, we demonstrate that the discrepancies for such structures originate from a particular combination of defects that give rise to charge transfer excitations, which are poorly described by XC potentials that do not contain sufficient Hartree Fock like exchange. Finally, we consider that such defects are readily healed in the presence of ubiquitously present water and that, as a result, the description of vertical low energy excitations for hydrated TiO2 nanoparticles is nonproblematic.", "author_names": [ "Enrico Berardo", "Han-Shi Hu", "Stephen Andrew Shevlin", "Scott M Woodley", "Karol Kowalski", "Martijn A Zwijnenburg" ], "corpus_id": 21446106, "doc_id": "21446106", "n_citations": 52, "n_key_citations": 0, "score": 0, "title": "Modeling Excited States in TiO2 Nanoparticles: On the Accuracy of a TD DFT Based Description", "venue": "Journal of chemical theory and computation", "year": 2014 }, { "abstract": "Meteorological drought indices are commonly calculated using data from weather stations and then interpolated to create a map of moisture conditions. These maps are used to communicate drought information to decision makers and the general public. This study analyzes five of the factors (drought index, interpolation method, seasonality, climate region, and station density) that influence the accuracy of these maps. This study compared the Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI) using data from the Cooperative Observer Network (COOP) and United States Historical Climatology Network (USHCN) The accuracy of the drought maps varied significantly over time and space. The most significant factor affecting the accuracy of the meteorological drought maps was seasonality. Errors were higher in regions (e.g. southeastern U.S. and months (e.g. summer) dominated by convective precipitation. The choice of interpolation method also had an influence. We found that Ordinary Kriging (OK) performed better than Inverse Distance Weighting (IDW) in all cases and therefore it was recommended for interpolating drought indices. Not surprisingly, maps that were created using more stations (COOP) were more accurate. The normalized errors of SPI and SPEI were very similar and so the choice of drought index had little impact on the accuracy of the drought maps.", "author_names": [ "Shanshui Yuan", "Steven M Quiring", "S Patil" ], "corpus_id": 61837186, "doc_id": "61837186", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Spatial and temporal variations in the accuracy of meteorological drought indices", "venue": "CIG 2016", "year": 2016 } ]

[ { "abstract": "The photoconductive decay is analysed by identifying the traps which interact with the excess free carrier density in the initial part of the decay. The analysis may account for the experimental observation that decay times for amorphous semiconductors are much shorter than expected from the traditional analysis, in which the decay time is calculated from the trapped carrier density in the band tail or the position of the quasi Fermi energy. The overestimate of the role of those states which contain trapped carriers but to which free carrier trapping occurs on a longer time scale than recombination is assessed. Our considerations are supported by the numerical solution of the time dependent rate equations.", "author_names": [ "Rudolf Bruggemann" ], "corpus_id": 95574970, "doc_id": "95574970", "n_citations": 10, "n_key_citations": 0, "score": 1, "title": "Analysis of the photoconductive decay from a trapping perspective", "venue": "", "year": 1997 }, { "abstract": "The present work studies the space charge accumulation and decay in the degassed cross linked polyethylene (XLPE) by detrapping mechanism and quantum chemical method. Experimentally, significant positive charge packets were observed at room temperature (300 K) Negative charges accumulated strikingly under high temperatures but with a fast decay during depolarization. The estimated bipolar carrier mobility and electron/hole trap depth that derived from the charge decay characteristics indicated that a shallow trap distribution (0.84 0.9 eV) dominates the space charge behavior. Additionally, a high temperature >60 degC) benefits to evaluate the deep traps (0.9 1 eV) Quantum chemical analysis using density functional theory (DFT) demonstrated that both the localized states for shallow electron and hole traps exist in the electronic structure of the XLPE structures. The former is derived from the physical disorder and crosslinks. The latter is ascribed to the hopping interaction between the chain terminal and the other orientated chains. The calculation results about the charge trapping characteristics agree with the experiments. Furthermore, the role of charge injection at the electrode/dielectric interface is also discussed.", "author_names": [ "Welwang Wang", "Tatsuo Takada", "Yasuhiro Tanaka", "Shengtao Li" ], "corpus_id": 12148541, "doc_id": "12148541", "n_citations": 17, "n_key_citations": 2, "score": 0, "title": "Trap controlled charge decay and quantum chemical analysis of charge transfer and trapping in XLPE", "venue": "IEEE Transactions on Dielectrics and Electrical Insulation", "year": 2017 }, { "abstract": "Abstract Starting from the multiple trapping rate equations that define the non equilibrium concentrations of electrons and holes in extended states, the experiment of photocurrent decay from the steady state is examined. A system of non linear coupled differential equations is solved to get the temporal evolution of the occupation functions and the carrier concentrations after cessation of the illumination. Different expressions proposed in the literature to evaluate the carrier lifetimes from the photocurrent decay data are critically examined. Measurements performed on a series of hydrogenated amorphous silicon samples deposited at different substrate temperatures are reproduced by the simulations. It is found that the response time determined from the photocurrent initial rate of decay provides an excellent estimation of the free lifetime of the majority carrier, provided the decay is recorded from sufficiently short times. It is also found that the common recombination lifetime can also be estimated from the photocurrent decay data.", "author_names": [ "Javier Schmidt", "D M Goldie" ], "corpus_id": 214497742, "doc_id": "214497742", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Photocurrent decay from the steady state in thin film hydrogenated amorphous silicon: Numerical simulation analysis of experimental results", "venue": "", "year": 2020 }, { "abstract": "The photoconductive decay (PCD) method of carrier lifetime measurement is discussed with emphasis on experimental and analytical work done at NBS. The relationship between photoconductive decay time Tpgn, bulk decay time x and lifetime is described briefly and the PCD method is summarized. The determination of x from x and the influence of higher modes of recombination are discussed. Experimental data, supported by theoretical considerations, are presented to demonstrate the dependence of xpqq on excess carrier density, the type of light source, specimen homogeneity, filter thickness, and temperature. The dependences of xp^rj on excess carrier density and temperature are consequences of the statistics of the recombination process. Measurements made with chopped light excitation are shown to be less in error due to higher modes of recombination than are measurements made with pulsed light excitation. The presence of inhomogeneities is verified in two crystals. Use of a filter is also shown to reduce the influence of higher modes. An unexpected reduction in x with increasing filter thickness is shown to be caused by an inhomogeneity Other experimental conditions are discussed as they affect the measurement of XpQj) It is shown that the light turnoff must be sufficiently fast and the series resistance sufficiently large that they do not interfere with the measurement. Equations are developed whereby the specimen current and illumination pattern can be chosen such that carrier sweep out at the ends of the specimen and ohmic heating are avoided. The end contacts must be sufficiently ohmic that excessive contact resistance does not interfere with the measurement. Trapping is defined and the means for identifying it are discussed briefly. The PCD method is inappropriate for determining minority carrier lifetime when trapping is present or under other circumstances when the hole and electron lifetimes are unequal.", "author_names": [ "Richard L Mattis" ], "corpus_id": 139916646, "doc_id": "139916646", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Carrier Lifetime Measurement by the Photoconductive Decay Method", "venue": "", "year": 2017 }, { "abstract": "Maternal genes play an important role in the early embryonic development of the silkworm. Early embryonic development without new transcription depends on maternal components stored in the egg during oocyte maturation. The maternal to zygotic transition (MZT) is a tightly regulated process that includes maternal mRNAs elimination and zygotic transcription initiation. This process has been extensively studied within model species. Each model organism has a unique pattern of maternal transcriptional clearance classes in MZT. In this study, we identified 66 maternal genes through bioinformatics analysis and expression analysis in the eggs of silkworm virgin moths (Bombyx mori) All 66 maternal genes were expressed in vitellogenesis in day eight female pupae. During MZT, the degradation of maternal gene mRNAs could be divided into three clusters. We found that eight maternal genes of cluster 1 remained stable from 0 to 3.0 h, 17 maternal genes of cluster 2 were significantly decayed from 0.5 to 1.0 h and 41 maternal genes of cluster 3 were significantly decayed after 1.5 h. Therefore, the initial time point of degradation of cluster 2 was earlier than that of cluster 3. The maternal gene mRNAs decay of clusters 2 and 3 is first initiated by maternal degradation activity. Our study expands upon the identification of silkworm maternal genes and provides a perspective for further research of the embryo development in Bombyx mori.", "author_names": [ "Meirong Zhang", "Pingzhen Xu", "Huilin Pang", "Tao Chen", "Guozheng Zhang" ], "corpus_id": 207961849, "doc_id": "207961849", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Expression Analysis of mRNA Decay of Maternal Genes during Bombyx mori Maternal to Zygotic Transition", "venue": "International journal of molecular sciences", "year": 2019 }, { "abstract": "A discussion of recombination and trapping kinetics is presented from the point of view of application to the analysis of transient photoconductive decay measurements in semiconductors. The transient solution is reviewed for the case of recombination in a single level, and the limiting approximations are presented for the case of n type material. The role of minority carrier trapping in transient measurements is discussed, along with the effect of recombination in the trapping center. It is found that trapping effects can be treated as a special case in the recombination equations. Separation of the recombination and trapping effects in various temperature ranges is discussed.", "author_names": [ "Ben G Streetman" ], "corpus_id": 122968934, "doc_id": "122968934", "n_citations": 28, "n_key_citations": 0, "score": 0, "title": "Carrier Recombination and Trapping Effects in Transient Photoconductive Decay Measurements", "venue": "", "year": 1966 }, { "abstract": "There has been keen interest for years in the research of all solid state transmittance type electrochromic (EC) devices due to their various applications especially in 'smart windows' A step forward has been taken in the successful preparation of full multilayered devices with enlarged optical contrast and fast switching response. However, limited durability remains a severe issue. Upon cycling, EC devices suffer from decline of charge capacity as well as optical modulation while the detailed degradation mechanisms remain poorly understood. Here, we demonstrate unambiguous ion trapping evidence to interpret the charge density decay of the EC device induced using various voltammetric cycling protocols, namely long term cycling and accelerated cycling. Pronounced comparable ion trapping occurs in cathodically colored WO3 films whatever the cycling procedure is, suggesting the existence of the trapping 'saturation' phenomenon. From second ion mass spectroscopy analysis, the 7Li+/184W+ ratio in the degraded WO3 films is more than 100 while it is almost zero in the as prepared films. In contrast, for anodically colored NiO, a larger number of trapped cations is determined in the long term cycled films than in the accelerated ones. In combination with X ray photoelectron spectroscopy, variable bonding energies indicate that the ions are trapped at different types of sites, depending on the cycling procedure, and they can reside in the structural channels or break the network chains to form new chemical bondings, thus resulting in a significant color difference. In addition, a clear upward trend in the trapped Li concentration along with depth is observed. All our findings provide a deep insight into the degradation phenomenon taking place in electrochromic films as well as in full devices and offer valuable information for the understanding of micro mechanisms.", "author_names": [ "Dongmei Dong", "Wenwen Wang", "Aline Rougier", "Antoine Barnabe", "Guobo Dong", "Fan Zhang", "Xungang Diao" ], "corpus_id": 139515540, "doc_id": "139515540", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Lithium trapping as a degradation mechanism of the electrochromic properties of all solid state WO3//NiO devices", "venue": "", "year": 2018 }, { "abstract": "We use photoconductivity time, optical absorption, and electron quantum efficiency measurements under in situ reactant CO2 H2 atmospheres to determine the role of surface trap states during photoreduction of CO2 to CO using In2O3 xOH y nanorods of varied annealing times. Photocurrent decay trends show an asymmetric energy distribution of surface barrier potentials with increased asymmetry from vacuum to CO2 H2. Urbach analysis shows crystalline disorder parameters of 0.35 0.40 under vacuum and 0.45 0.6 under CO2 H2. Quantum efficiency spectra show that under H2 CO2 average tail state energies are similar to those under vacuum but with increased densities of photoconductive gap states. Photoelectro paramagnetic resonance measurements show the creation of new paramagnetic centers. Overall, enhanced activity is associated with a lower maximum barrier potential of 0.39 eV than that of 0.41 eV, lower average trap energies of 2.58 eV compared to 2.69 eV, with higher disorder due to increased surface state densities. These techniques pave the way for facile in situ probing of gas phase photocatalysts, providing simple macrolevel understanding of adsorbed reactants on surface band bending, thus correlating to catalytic efficacy.", "author_names": [ "Joel Y Y Loh", "Nazir P Kherani" ], "corpus_id": 58651681, "doc_id": "58651681", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "In Situ Electronic Probing of Photoconductive Trap States for the Catalytic Reduction of CO2 by In2O3 xOH y Nanorods.", "venue": "The journal of physical chemistry letters", "year": 2019 }, { "abstract": "The greater the separation in time between 2 events, A followed by B, the less likely they are to become associated. The dominant explanation of this temporal contiguity effect has been trace decay: During the interval between A and B, the trace left by A becomes too weak by the time B occurs for an association to be formed between them. Pavlov adopted this idea in the context of classical conditioning and Hull used it to account for the deleterious effect of delaying reinforcement on the acquisition of instrumental responses. By 1960 various studies supported the conclusion that animals could not learn to associate 2 events separated by more than around 45 s. Research on human skill acquisition with delayed feedback and later studies using causal or predictive judgment tasks indicated that explicit cognitive processing is generally involved when humans associate events separated by more than a few seconds. The discovery of long delay taste aversion learning prompted Revusky's (1971) alternative analysis of contiguity effects in terms of interference: The greater the separation between A and B, the more likely that extraneous events compete for association with A and B. Although the analysis of overshadowing provided by associative learning theories provides a context for this account, none of these theories provide a satisfactory account of evidence on temporal contiguity from a wide range of animal studies. Alternative timing theories are arguably also unsatisfactory.", "author_names": [ "Robert A Boakes", "Daniel S J Costa" ], "corpus_id": 21767138, "doc_id": "21767138", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Temporal contiguity in associative learning: Interference and decay from an historical perspective.", "venue": "Journal of experimental psychology. Animal learning and cognition", "year": 2014 }, { "abstract": "MRST co2lab is a collection of open source computational tools for modeling large scale and long time migration of CO2 in conductive aquifers, combining ideas from basin modeling, computational geometry, hydrology, and reservoir simulation. Herein, we employ the methods of MRST co2lab to study long term CO2 storage on the scale of hundreds of megatonnes. We consider public data sets of two aquifers from the Norwegian North Sea and use geometrical methods for identifying structural traps, percolation type methods for identifying potential spill paths, and vertical equilibrium methods for efficient simulation of structural, residual, and solubility trapping in a thousand year perspective. In particular, we investigate how data resolution affects estimates of storage capacity and discuss workflows for identifying good injection sites and optimizing injection strategies. HighlightsOutline open source tools for estimating CO2 storage potential in saline aquifers.Study how data resolution impacts estimates of structural trapping capacity.Develop plausible injection plans for storing gigatonnes of CO2.Examples: Johansen and Utsira from the CO2 Storage Atlas of the Norwegian North Sea.", "author_names": [ "Halvor Moll Nilsen", "Knut-Andreas Lie", "Odd Andersen" ], "corpus_id": 17717212, "doc_id": "17717212", "n_citations": 34, "n_key_citations": 1, "score": 0, "title": "Analysis of CO2 trapping capacities and long term migration for geological formations in the Norwegian North Sea using MRST co2lab", "venue": "Comput. Geosci.", "year": 2015 } ]

[ { "abstract": "We demonstrate and characterize polarization division multiplexed (PDM) DWDM data transmission for the first time in a range of systems incorporating a net gain polarization insensitive fiber optical parametric amplifier (PI FOPA) for loss compensation. The PI FOPA comprises a modified diversity loop architecture to achieve 15dB net gain, and up to 2.3THz ~18nm) bandwidth. Three representative systems are characterized using a 100Gb/s PDM QPSK signal in conjunction with emulated DWDM neighbouring channels: (a) a 4x75km in line fiber transmission system incorporating multiple EDFAs and a single PI FOPA (b) N cascaded PI FOPA amplification stages in an unlevelled Nx25km recirculating loop arrangement, with no EDFAs used within the loop signal path, and (c) M cascaded PI FOPA amplification stages as part of an Mx75.6km gain flattened recirculating loop system with the FOPA compensating for the transmission fiber loss, and EDFA compensation for loop switching and levelling loss. For the 4x75km in line system (a) we transmit 45x50GHz spaced signals 'equivalent' data rate of 4.5Tb/s) with average OSNR penalty of 1.3dB over the band at 10 BER. For the unlevelled 'FOPA only' 25.2km cascaded system (b) we report a maximum of eight recirculations for all 10x100GHz spaced signals, and five recirculations for 20x50GHz spaced signals. For the 75.6km levelled system (c) we achieve eight recirculations for all 20x50GHz signals resulting in a total transmission distance of 604.8km. (c) 2017 Optical Society of America OCIS codes: (060.2320) Fiber optics amplifiers and oscillators; (060.2330) Fiber optics communications; (190.4410) Nonlinear optics, parametric processes. References and links 1. M. Islam, \"Raman amplifiers for telecommunications,\" IEEE J. Sel. Topics Quantum Electron. 8(3) 548 559 (2002) 2. C. Headley and G. P. Agrawal, Raman amplification in fiber optical communication systems (Academic, 2005) 3. R. Kashyap, \"The fiber fuse from a curious effect to a critical issue: A 25th year retrospective,\" Opt. express 21(5) 6422 6441 (2013) 4. M. J. O' Mahony, \"Semiconductor laser optical amplifiers for use in future fiber systems,\" IEEE J. Lightw. Technol. 6(4) 531 544 (1988) 5. M. F. C. Stephens, D. Nesset, R. V. Penty, I. H. White, and M. J. Fice, \"Wavelength conversion at 40 Gbit/s via four wave mixing in semiconductor optical amplifier with integrated pump laser,\" Electronics Letters 35(5) 420421, (1999) 6. Z. Li, A. M. Heidt, J. M. O. Daniel, Y. Jung, S. U. Alam, and D. J. Richardson, \"Thulium doped fiber amplifier for optical communications at 2 mm,\" Opt. Express 21(8) 9289 9297 (2013) 7. N. Simakov, Z. Li, Y. Jung, J. M. O. Daniel, P. Barua, P. C. Shardlow, S. Liang, J. K. Sahu, A. Hemming, W. A. Clarkson, S. U. Alam, and D. J. Richardson, \"High gain holmium doped fibre amplifier,\" Opt. Express 24(13) 13946 13956 (2016) 8. F. Poletti, N. V. Wheeler, M. N. Petrovich, N. K. Baddela, E. Numkam Fokoua, J. R. Hayes, D. R. Gray, Z. Li, R. Slavik, and D. J. Richardson, \"Towards high capacity fibre optic communications at the speed of light in vacuum,\" Nat. Photonics 7(4) 279 284 (2013) 9. V. Gordienko, M. F. C. Stephens, A. E. El Taher, and N. J. Doran, \"Ultra flat wideband single pump Ramanenhanced parametric amplification,\" Opt. Express 25(5) 4810 4818 (2017) 10. Z. Tong, C. Lundstrom, P. A. Andrekson, M. Karlsson, and A. Bogris, \"Ultralow noise, broadband phasesensitive optical amplifiers, and their applications,\" IEEE IEEE J. Sel. Topics Quantum Electron. 18(2) 10161032 (2012) 11. M. F. C. Stephens, M. Tan, I.D. Phillips, S. Sygletos, P. Harper, and N.J. Doran, \"1.14 Tb/s DP QPSK WDM polarization diverse optical phase conjugation,\" Opt. Express 22(10) 11840 11848 (2014) 12. A. D Ellis, M. Tan, M. A. Iqbal, M. A. Z. Al Khateeb, V. Gordienko, G. S. Mondaca, S. Fabbri, M. F. C. Stephens, M. E. McCarthy, A. Perentos, I. D. Phillips, D. Lavery, G. Liga, R. Maher, P. Harper, N. Doran, S. K. Turitsyn, S. Sygletos, and P. Bayvel, \"4 Tb/s transmission reach enhancement using 10x 400 Gb/s superchannels and polarization insensitive dual band optical phase conjugation,\" IEEE J. Lightw. Technol. 34(8) 1717 1723 (2016) 13. S. Takasaka, and R. Sugizaki, \"Polarization Insensitive Fiber Optical Parametric Amplifier Using a SBS Suppressed Diversity Loop,\" in Optical Fiber Communication Conference (Optical Society of America, 2016) paper M3D.4. 14. M. F. C. Stephens, V. Gordienko, and N.J. Doran, \"20 dB net gain polarization insensitive fiber optical parametric amplifier with> 2 THz bandwidth,\" Opt. Express 25(9) 10597 10609 (2017) 15. L. Gruner Nielsen, D. Jakobsen, S. Herstrom, B. Palsdottir, S. Dasgupta, D. Richardson, C. Lundstrom, S. Olsson, and P. Andrekson, \"Brillouin Suppressed Highly Nonlinear Fibers,\" in European Conference on Optical Communication (ECOC 2012) paper We.1.F.1. 16. M. F. C. Stephens, I. D. Phillips, P. Rosa, P. Harper, and N. J. Doran, \"Improved WDM performance of a fiber optical parametric amplifier using Raman assisted pumping,\" Opt. Express 23(2) 902 911 (2015) 17. A. Redyuk, M. F. C. Stephens, and N. J. Doran, \"Suppression of WDM four wave mixing crosstalk in fibre optic parametric amplifier using Raman assisted pumping,\" Opt. Express 23(21) 27240 27249 (2015) 18. J. D. Marconi, M. C. Fugihara, F. A. Callegari, and H. L. Fragnito, \"In line one pump parametric amplifier with independent polarization gain: a field trial demonstration,\" Microwave and Optical Tech. Lett. 55(5) 1104 1107 (2013) 19. Z. Lali Dastjerdi, O. Ozolins, Y. An, V. Cristofori, F. Da Ros, N. Kang, H. Hu, H. C. H. Mulvad, K. Rottwitt, M. Galili, and C. Peucheret, \"Demonstration of cascaded in line single pump fiber optical parametric amplifiers in recirculating loop transmission,\" in European Conference on Optical Communication (ECOC 2012) paper Mo.2.C.5. 20. N. El Dahdah, D. S. Govan, M. Jamshidifar, N. J. Doran, and M. E. Marhic, \"Fiber Optical Parametric Amplifier Performance in a 1 Tb/s DWDM Communication System\" IEEE IEEE J. Sel. Topics Quantum Electron. 18(2) 950 957 (2012) 21. D. Elson, G. Saavedra, K. Shi, D. Semrau, L. Galdino, R. Killey, B. Thomsen, and P. Bayvel, \"Investigation of bandwidth loading in optical fibre transmission using amplified spontaneous emission noise,\" Opt. Express 25(16) 19529 19537 (2017) 22. M. McCarthy, N. Mac Suibhne, S. T. Le, P. Harper, and A. D. Ellis, \"High spectral efficiency transmission emulation for non linear transmission performance estimation for high order modulation formats,\" in European Conference on Optical Communication (ECOC 2014) paper P.5.7. 23. J. Hansryd, P. A. Andrekson, M. Westlund, J. Li, and P. O. Hedekvist, \"Fiber based optical parametric amplifiers and their applications,\" IEEE J. Sel. Top. Quantum Electron. 8(3) 506 520 (2002) 24. M. F. C. Stephens, A. Redyuk, S, Sygletos, I. D. Phillips, P. Harper, K. J. Blow, and N. J. Doran, \"The Impact of Pump Phase Modulation and Filtering on WDM Signals in a Fiber Optical Parametric Amplifier,\" in Optical Fiber Communication Conference (Optical Society of America, 2016) paper W2A.43. 25. J. M. Chavez Boggio, A. Guimaraes, F. A. Callegari, J. D. Marconi, and H. L. Fragnito, \"Q penalties due to pump phase modulation and pump RIN in fiber optic parametric amplifiers with non uniform dispersion,\" Opt. Commun. 249(4) 451 472 (2005) 26. A. Mussot, A. Durecu Legrand, E. Lantz, C. Simonneau, D. Bayart, H. Maillotte, and T. Sylvestre, \"Impact of pump phase modulation on the gain of fiber optical parametric amplifier,\" IEEE Photon. Technol. Lett. 16(5) 1289 1291 (2004) 27. J. M. Chavez Boggio, J. D. Marconi, and H. L. Fragnito, \"Experimental and numerical investigation of the SBSthreshold increase in an optical fiber by applying strain distributions,\" J. Lightw. Technol. 23(11) 3808 3814 (2005) 28. Z. Lali Dastjerdi, T. Lund Hansen, N. Kang, K. Rottwitt, M. Galili, and C. Peucheret, \"High frequency RIN transfer in fiber optic parametric amplifiers,\" in Conference on Lasers and Electro Optics Europe (CLEOEurope 2011) paper CI2.5. 29. F. Zhang, Y. Luo, Y.Wang, L. Li, L. Zhu, Z. Chen, and C. Wu, \"Experimental Comparison of Different BER Estimation Methods for Coherent Optical QPSK Transmission Systems,\" IEEE Photon. Technol. Lett. 23(18) 1343 1345 (2011)", "author_names": [ "Steiner Mfc", "", "G V", "H P", "Dowie Nj" ], "corpus_id": 67811590, "doc_id": "67811590", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "In line and cascaded DWDM transmission using a 15 dB net gain polarization insensitive fiber optical parametric amplifier", "venue": "", "year": 2017 }, { "abstract": "Optical fibres have been developed as an ideal medium for the delivery of optical pulses ever since their inception (Kao Hockham, 1966) Much of that development has been focused on the transmission of low energy pulses for communication purposes and thus fibres have been optimised for singlemode guidance with minimum propagation losses only limited by the intrinsic material absorption of silica glass of about 0.2dB/km in the near infrared part of the spectrum (Miya et al. 1979) The corresponding increase in accessible transmission length simultaneously started the interest in nonlinear fibre optics, for example with early work on the stimulated Raman effect (Stolen et al. 1972) and on optical solitons (Hasegawa Tappert, 1973) Since the advent of fibre amplifiers (Mears et al. 1987) available fibre coupled laser powers have been increasing dramatically and, in particular, fibre lasers now exceed kW levels in continuous wave (cw) operation (Jeong et al. 2004) and MW peak powers for pulses (Galvanauskas et al. 2007) in all fibre systems. These developments are pushing the limits of current fibre technology, demanding fibres with larger mode areas and higher damage threshold. However, it is increasingly difficult to meet these requirements with fibres supporting one single optical mode and therefore often multiple modes are guided. Non fibre based laser systems are capable of delivering even larger peak powers, for example commercial Ti:sapphire fs lasers now reach the GW regime. Such extreme powers cannot be transmitted in conventional glass fibres at all without destroying them (Gaeta, 2000) but there is a range of applications for such pulses coupled into hollow core capillaries, such as pulse compression (Sartania et al. 1997) and high harmonic generation (Rundquist et al. 1998) For typical experimental parameters, these capillaries act as optical waveguides for a large number of spatial modes and modal interactions contribute significantly to the system dynamics. In order to design ever more efficient fibre lasers, to optimise pulse delivery and to control nonlinear applications in the high power regime, a thorough understanding of pulse propagation and nonlinear interactions in multimode fibres and waveguides is required. The conventional tools for modelling and investigating such systems are based on beam propagation methods (Okamoto, 2006) However, these are numerically expensive and provide little insight into the dependence of fundamental nonlinear processes on specific fibre properties, e.g. on transverse mode functions, dispersion and nonlinear mode coupling. For such an interpretation a multimode equivalent of the nonlinear Schrodinger equation, the standard and highly accurate method for describing singlemode nonlinear pulse propagation (Agrawal, 2001; Blow Wood, 1989) is desirable. In this chapter, we discuss the basics of such a multimode generalised nonlinear Schrodinger equation (Poletti Horak, 2008) its simplification to experimentally relevant situations and a few select applications. We start by introducing and discussing the theoretical framework for fibres with chi(3) nonlinearity in Sec. 2. The following sections are devoted to multimode nonlinear applications, presented in the order of increasing laser peak powers. A sample application in the multi kW regime is supercontinuum generation, discussed in Sec. 3. Here we demonstrate how fibre mode symmetries and launching conditions affect intermodal power transfer and spectral broadening. For peak powers in the MW regime, self focusing effects become significant and lead to strong mode coupling. The spatio temporal evolution of pulses in this limit is the topic of Sec. 4. Finally, at GW peak power levels, optical pulses can only be delivered by propagation in gases. Still, intensities become so high that nonlinear effects related to ionisation must be taken into account. An extension of the multimode theory to include these extreme high power effects is presented in Sec. 5 and the significance of mode interaction is demonstrated by numerical examples pertaining to a recent experiment. Finally, we end this chapter with conclusions in Sec. 6", "author_names": [ "Peter Horak", "Francesco Poletti" ], "corpus_id": 56419837, "doc_id": "56419837", "n_citations": 27, "n_key_citations": 4, "score": 0, "title": "Multimode Nonlinear Fibre Optics: Theory and Applications", "venue": "", "year": 2012 }, { "abstract": "Metal based additive manufacturing enables the production of even complex shaped parts that cannot be produced with conventional processes (e.g. milling) Taking advantage of the geometrical freedom in part production, an increasing number of industrial applications nowadays resort to these techniques. Hence, the additive manufacturing technology has currently passed the threshold from prototyping to mass production. This requires short processing times which are potentially reached by the adoption of multiple lasers with increasing output power. Typically, single mode lasers are used to reach customer demands, e.g. surface smoothness. An optical setup of fibre beam delivery, collimation, focusing, and beam deflection is utilized to allow laser scan velocities of up to 1000 mm/s. For future applications of laser powers in the range of several kilowatts a critical level of absorbed power in these optical elements is likely to occur. The resulting thermally induced focal shift can lead to an undesirable beam defocussing and the corresponding increase of beam diameter will then lead to a loss of intensity in the powder bed interaction zone. To encounter this challenge for a future utilization of even higher laser powers, measures can be taken to reduce thermally induced focal shift. One possible approach comprises the insertion of additional optical glasses which compensate the focal shift by means of a converse thermal behaviour, i.e. negative refraction index gradient. Related to this topic, the measurement of absorption in optical components and the power dependent focal position are presented within this work. Laboratory measurements are complemented by the application of the corresponding results on an appropriate manufacturing system configuration. The investigations demonstrate that the desired reduction of thermally induced focal shift can be reached.", "author_names": [ "" ], "corpus_id": 199523158, "doc_id": "199523158", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Lasers in Manufacturing Conference 2015 Reliable Beam Positioning for Metal based Additive Manufacturing by Means of Focal Shift Reduction", "venue": "", "year": 2015 }, { "abstract": "Organisms are under strong selection to respond adaptively to environmental stress, even when different stresses occur simultaneously or in rapid succession, as they often do in natural environments. However, at a molecular level, stress responses are often studied in isolation and under controlled growth conditions. This leaves us with an ever finer picture of single stress responses but little understanding of how additional stressors modify those responses. Without companion studies of more complex systems of interacting stresses, we do not know how phenotypes are shaped under natural conditions. Based on whole organism studies in largely agricultural settings, we do know that stresses interact profoundly to shape phenotypes. We also have examples of cross talk among signalling pathways associated with specific abiotic and biotic stress responses which hint at the existence of mechanisms that may integrate global plant stress responses. To move plant stress biology forward in transformative ways, we need greater collaboration among plant biologists studying different stresses in order to address the complexity of plant stress responses under natural conditions. In 2015, the University of Missouri Interdisciplinary Plant Group (IPG) organized its annual symposium around the topic of Plants Between a Rock and a Hard Place: The Interface between Plant Abiotic and Biotic Stress Responses. A primary goal of the meeting was to promote and enhance multi stress collaboration within the plant stress biology community by bringing together world renowned experts in different aspects of plant stress biology who have already begun to study the interactions between different stresses. In this special issue of the Journal of Experimental Botany, we present some of the topics and research that were covered at the symposium. Foyer et al. (2016) set the stage with a detailed look at how an abiotic stress can shape a plant's response to attack by phloem feeding aphids. They present a strong case to challenge the oft held notion that abiotic stress events result in an increased susceptibility to biotic stress factors. The complex signalling pathways that direct plant responses to abiotic and biotic stressors overlap in many ways that lead to cross tolerance phenomena. The plant's response to aphid infestation involves interactions between hormone, redox, nitric oxide, kinase, and calcium signalling pathways that mirror aspects of the plant's response to abiotic factors. The preponderance of evidence suggests that abiotic stressors do not predispose a plant to aphid attack and, in fact, may provide some measure of protection and that this may hold true for other abiotic biotic stressor interactions. Viruses depend on vectors such as plant associated insects to move from plant to plant. To spread throughout an infected plant successfully and to facilitate vector transmission to another, viruses must manipulate the cellular processes of the host with a very limited set of proteins encoded in their small genomes. Studying these proteins from viruses and other plant associated pathogens can provide novel insights into the processes involved in abiotic and biotic stress responses. Schoelz et al. (2016) provide an intriguing overview of the multifunctional P6 protein of Cauliflower Mosaic Virus, a novel function of which is to direct large protein assemblies devoted to virus replication into plasmodesmata for cell to cell movement. In contrast to viruses, most microbial pathogens of plants do not enter the host cytoplasm. A first line of defence, therefore, occurs at the plant plasma membrane where receptors detect conserved non self molecules collectively called microbe or pathogen associated molecular patterns (M/PAMPs) to initiate a broad defence response termed PAMP triggered immunity (PTI) (Macho and Zipfel, 2014) While PAMPs and the corresponding plant receptors have been identified for a variety of microbial pathogens, a notable exception has been PAMPs derived from plant parasitic nematodes. The review by Holbein et al. (2016) provides a fascinating update on progress in identifying elements of plant PTI responses to nematodes, thus broadening the arsenal for breeding resistance into crop plants. Biotic and abiotic stressors often elicit systemic responses which depend on signalling from local sites of exposure to other areas of the plant. At the cellular or tissue level, the possible interplay between the various signalling pathways can be complex, especially when two or more stressors are combined as is often the case in the field. Huber and Bauerle (2016) describe the hydraulic, chemical, and electrical components that are part of the long distance communication array of all plants. They provide a comprehensive assessment of what is known about how they operate and interact to co ordinate a systemic response in the plant. The authors highlight the large gaps in knowledge that need to be addressed and make clear that combinations of stressors often elicit novel responses that differ from responses to single stressors. Plant responses to abiotic and biotic stressors can lead to changes that appear to be 'memorized' and influence the stress tolerance of the next generation. The review by Bilichak and Kovalchuk (2016) explores possible epigenetic mechanisms associated with this phenomenon, highlighting the evidence that certain stress induced epigenetic factors escape full scale reprogramming of the epigenome during gametogenesis. The authors speculate that a better understanding of these epigenetic factors would enable the engineering of epigenetic modifications to cross stress tolerance for crop improvement strategies in plant breeding. The symposium was also an opportunity to showcase new and focused unpublished data. The research paper by MacQueen and Bergelson (2016) focuses on plant innate immunity to microbial pathogens. They show that abiotic factors such as temperature and humidity, which are known to influence pathogen aggressiveness, impact expression levels of plant resistance genes. These resistance genes provide a second line of defence against microbial pathogens, but their continued high expression reduces plant fitness. Therefore, modulation of resistance gene expression levels by abiotic factors probably reflects an adaptive advantage by balancing plant defence readiness and fitness in the absence of pathogens. Finally, the research paper by Zhang et al. (2016) identifies an intriguing connection between the auxin and jasmonic acid (JA) signalling pathways via hormone metabolism. Even though auxin and JA regulate quite distinct developmental and stress response pathways, it was found that some of the indole 3 acetic acid (IAA) hydrolases (IAH) also metabolize JA isoleucine, a bioactive derivative of JA. Manipulation of IAH expression levels led to surprising perturbations of these hormone signalling modules, highlighting the degree to which these two signalling pathways are interconnected via metabolic cross talk. Worldwide, humans rely on plants for food, fibre, and fuel, and face the daunting task of growing food for nine billion people by 2050 while reducing the carbon, fertilizer, and water footprint of agriculture. In addition, the consensus prediction is that global climate change will destabilize plant growth conditions in terms of higher CO2 levels and increased risks of severe fluctuations in temperature and precipitation (Schroeder et al. 2013) These adverse abiotic conditions will most likely favour the spread of plant pathogens and pests into new geographic areas. Such a scenario increases the need to develop abiotic stress and pathogen and pest resistant crop plants at a speed that cannot be met by breeding alone (Dangl et al. 2013) The combination of abiotic and biotic stresses not only threatens agriculture but also plants in natural environments that fulfil important ecosystem services. Addressing these major challenges will require an interdisciplinary and concerted approach. We hope that our readers will find, as we did, that the reviews and research articles in this special issue provide a useful and stimulating contribution towards addressing these challenges. We are grateful to the sponsors of our symposium, in particular the National Science Foundation, the USDA National Institute of Food and Agriculture, and the Journal of Experimental Botany for their support.", "author_names": [ "Walter Gassmann", "Heidi M Appel", "Melvin J Oliver" ], "corpus_id": 46050657, "doc_id": "46050657", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "The interface between abiotic and biotic stress responses", "venue": "Journal of experimental botany", "year": 2016 }, { "abstract": "The measured bending field of the CERN Proton Synchrotron (PS) is received in real time by the longitudinal beam control system and converted into the revolution frequency used as set point for beam phase and radial loops. With the renovation of the bending field measurement system the transmission technique is changed from a differential sequence of pulses, the so called B train, to a stream of Ethernet frames based on the White Rabbit protocol. The packets contain field, its derivative and auxiliary information. A new frequency program for the conversion of the bending field into the revolution frequency, depending also on parameters like radius of the accelerator and the particle type, has been developed. Instead of storing large conversion tables from field to frequency for fixed parameters, the frequencies are directly calculated in programmable logic (FPGA) In order to reduce development time and keep flexibility, the conversion is processed in real time in the FPGA using Xilinx floating point primitives mapped by a higher level tool Simulink System Generator. Commissioning with beam of the new frequency program in the PS is progressing.", "author_names": [ "Damien Perrelet", "Ylenia Brischetto", "Heiko Damerau", "Daniel Oberson", "Magnus Sundal", "A Villanueva" ], "corpus_id": 114633238, "doc_id": "114633238", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "White Rabbit Based Revolution Frequency Program for the Longitudinal Beam Control of the CERN PS", "venue": "", "year": 2015 }, { "abstract": "This book provides an excellent introduction to the topic of smart structures and materials. It is easy to read, being only 200 pages long. It begins with a layman's view of the topic, placing smart structures in terms of simple concepts before moving on to a step by step approach to the specifics. The style of the book is meant to be at the awareness level more than the detailed analysis level and the author achieves this successfully. The use of comparative tables in almost every chapter is particularly good for quickly disseminating information. All the important topics are covered, albeit somewhat briefly in some sections. The eight chapters span aspects such as materials, sensing and actuation and signal processing. Several case studies are included and the book concludes by contemplating where the future may be with regard to smart structures and materials. The most detailed chapter of the book deals with the author's principal research field, namely sensing technologies and optical fibres. It is somewhat unfortunate that this is the only chapter which offers a good list of references; this is the only real weakness of the book. Overall, this is a worthwhile purchase for undergraduates, researchers and industrialists who want to be exposed to the important developing area of smart materials and structures and who want an easy text to read on the subject. The author has done a splendid job of producing a book that should stimulate further interest in a technology which is clearly part of the future.", "author_names": [ "Geoffrey R Tomlinson" ], "corpus_id": 122278266, "doc_id": "122278266", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Smart Structures and Materials", "venue": "", "year": 1996 }, { "abstract": "The detailed knowledge of the temporal behaviour of astrophysical objects is one of the main sources of information about physical processes occurring in several classes of objects. In this PhD thesis we investigated two different astrophysical topics, both of them linked to timing. We present the scientific analysis of the data collected from the Crab pulsar by means of the novel optical extremely fast photon counters Aqueye and Iqueye, that have the best temporal resolution ever achieved in the optical domain (hundreds of picoseconds) Aqueye (Barbieri et al. 2008, 2009) was designed to be mounted at the Copernico telescope in Asiago. Iqueye (Naletto et al. 2009, 2010) is an improvedversion for the NTT telescope. Here we also discuss some ideas on modelling the millisecond variability observed in the X ray flux from Low Mass X ray Binaries with either a neutron star or a black hole. The timing analysis of the optical emission from the Crab pulsar requires to time tag with extreme precision the photons as collected by an inertial observer. Therefore we must refer the time of arrival of photons (TOAs) to a reference frame that approximates an inertial frame to the level of precision needed. One usually refers TOAs to a reference system located at the solar system barycenter. Tempo2 (Hobbs et al. 2006, Edwards et al. 2006) is a software meant to model with extreme precision (up to 1 ns) TOAs as collected by an inertial observer. After baricentering TOAs a numerical code making use of a standard template was used to determine the phase of the mean peak of the Crab pulsar profile. By studying the phase behaviour it is possible to extract information about both the rotational period of the fast rotating neutron star and its derivatives. Moreover, the analysis of the phase residuals left out after subtracting the standard pulsar timing model may reveal interesting features of the pulsar and its surroundings. With the anlysis of the residuals one can also check for possible discrepancies on the modelling. If some systematic residuals show up, then it is interesting to investigate the physical origin. Just to quote a few noticeable examples, we mention the discovery of the first extrasolar planetary system around the pulsar PSR B1257+12, obtained from the analysis of pulsar phase residuals (Wolszczan Frail 1992; Wolszczan 1994; Konacki Wolszczan 2003) Other foundamental results deal with tests of General Relativity theory (Helfand et al. 1980; Kramer et al. 2006) Moreover, pulsar timing is now being planned as a tool to reveal gravitational wave (Stappers et al. 2006; Manchester 2010) The analysis of the optical phase residuals of the Crab pulsar we performed has revealed poor corrections in the Roemer delay due to the Tempo2 configuration files. After correcting for them we can conclude that the rotational periods of the Crab pulsar measured by Aqueye/Iqueye agree with those quoted in the Jodrell Bank radio archive up to a few picoseconds. The TOAs from a photon counter usually are affected by noise that obeys the Poisson statistics. We noticed possible discrepancies between the radio and optical rotational periods larger than the estimated Poissonian error, but a more extensive analysis of the pulsar timing noise and related errors is needed before any definitive conclusion can be drawn. We were able to measure the spin down of the neutron star already over a baseline of a few days. Discrepancies with that reported in the Jodrell Bank radio archive are underlined. By comparing the time of arrival of the optical peak at the solar system barycenter with that quoted in the Jodrell Bank radio ephemerides archive we find a radio optical delay in agreement with that reported in the literature (Shearer et al. 2003; Oosterbroek et al. 2008) that is, an optical peak leading the radio one by about 120 microsec. We also noticed same radio optical phase drift with time, which may be related to the radio optical rotational period discrepancies mentioned above. A further investigation on the possible origin of these discrepancies led to the preliminary conclusion that the signal from the Crab pulsar may be affected by an extra noise component, known as timing noise, not suitable described by the Poissonian statistics. Non Poissonian noise in the signal from neutron stars has been reported by other authors (Boynton et al. 1972; Lyne et al. 1993; Scott et al. 2003; Hobbs et al. 2006b; Patruno et al. 2009) but using integration times of months or years. Further observations to confirm the existence of non Poissonian noise in the Crab pulsar are needed. In this PhD thesis we also present some ideas on the origin of the millisecond X ray timing variability in the X ray flux from Low Mass X ray Binaries (LMXBs) with either a black hole or a neutron star (e.g. van der Klis et al. 2004) These quasi periodic oscillations (QPOs) at frequencies up to 1200 Hz, were discovered by means of the X ray photon counters on board of the Rossi X ray Timing Explorer satellite (RXTE; Bradt et al. 1993) Millisecond time scales are typical for matter orbiting close to the compact object. Therefore, timing studies of these sources could provide a way to investigate the motion of matter in a strongly curved space time, thus probing General Relativity in the strong field limit. We describe some ideas on fitting relativistic frequencies in the Kerr metric to observed QPO frequencies in LMXBs. Using a grid of masses and specific angular momenta for the neutron star we show that numerical fits have a low kh2/dof for masses of the neutron star above 2 M. Such masses are bigger than the canonical value 1.4M measured in double radio pulsars. However, in accreting bynary systems a mass of the neutron star larger than the canonical value has been measured (Casares et al. 2006, 2010) We note that precise measurements of neutron star masses by means of millisecond QPOs are uncertain because of the yet poorly understood phenomenology. If high frequency QPOs in the X ray flux of LMXBs are produced by orbiting blobs of matter close to the compact object then a full consistent modelling should also account for the interaction of the shape of the blob with the curved geometry of the space time. In collaboration with the Department of Mathematics and Physics of the University of Ljubljana we ran simulations of light curves and power spectra produced by clumps of free particles orbiting a Schwarzschild black hole, that are deformed by tidal interaction. The numerical code was developed by (Cadez et al. 2008, Kostic et al. 2009) The numerical simulations reproduce the high frequency part of the power spectrum observed in the black hole LMXB XTE J1550 564 (Germana et al. 2009)", "author_names": [ "Claudio Germana" ], "corpus_id": 123878504, "doc_id": "123878504", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Timing studies of compact objects", "venue": "", "year": 2011 }, { "abstract": "Digital Signal Transmission: C. C. BISSELL and D. A. CHAPMAN (Cambridge University Press, 1992,321 pp. PS15.95, $34.95paperback, PS45, $79.95hardback) The subject of digital transmission is large and complex and a thorough treatment of the topic requires considerable detailed discussion and involves significant mathematical theory. However most students at undergraduate level require an easily readable text with the mathematical content kept to the bare essentials. This book is aimed at second and third year undergraduate students and practising engineers that require updating in modern techniques. The mathematical theory has been kept to a minimum and the standard mathematical results are presented in appendices. A large portion of the text has been derived from the authors' contributions to the Open University course on Digital Telecommunications and perhaps as a consequence the text is written in a style which makes it very suitable for self study. The book only considers a limited number of topics in depth and places the emphasis on the engineering aspects of digital transmission and interpretation of mathematical models. The chapters are grouped into three parts. Part I considers models and discusses continuous and discrete time signals and systems as well as random signals and noise. Part 2 describes processes and explains details of the pulses that are used for digital transmission, and it also discusses line codes and channel codes, including scrambling, block codes and convolution coding. The final part of the book is devoted to digital transmission over the public switched telephone network. The topics considered in this part are relevant analogue and digital signal sources, coding techniques, digital transmission hierarchies and the features of an optical fibre link. I found this an interesting and useful book which has been written with the undergraduate student very much in mind. It is very appropriate for use in universities as a student text for the typical telecommunication undergraduate course. ROBERT J. SIMPSON, Professor of Electronic Engineering, University of CentralLancashire", "author_names": [ "Robert J Simpson" ], "corpus_id": 117124757, "doc_id": "117124757", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Book Review: Digital Signal Transmission", "venue": "", "year": 1993 }, { "abstract": "Digital Signal Transmission: C. C. BISSELL and D. A. CHAPMAN (Cambridge University Press, 1992,321 pp. PS15.95, $34.95paperback, PS45, $79.95hardback) The subject of digital transmission is large and complex and a thorough treatment of the topic requires considerable detailed discussion and involves significant mathematical theory. However most students at undergraduate level require an easily readable text with the mathematical content kept to the bare essentials. This book is aimed at second and third year undergraduate students and practising engineers that require updating in modern techniques. The mathematical theory has been kept to a minimum and the standard mathematical results are presented in appendices. A large portion of the text has been derived from the authors' contributions to the Open University course on Digital Telecommunications and perhaps as a consequence the text is written in a style which makes it very suitable for self study. The book only considers a limited number of topics in depth and places the emphasis on the engineering aspects of digital transmission and interpretation of mathematical models. The chapters are grouped into three parts. Part I considers models and discusses continuous and discrete time signals and systems as well as random signals and noise. Part 2 describes processes and explains details of the pulses that are used for digital transmission, and it also discusses line codes and channel codes, including scrambling, block codes and convolution coding. The final part of the book is devoted to digital transmission over the public switched telephone network. The topics considered in this part are relevant analogue and digital signal sources, coding techniques, digital transmission hierarchies and the features of an optical fibre link. I found this an interesting and useful book which has been written with the undergraduate student very much in mind. It is very appropriate for use in universities as a student text for the typical telecommunication undergraduate course. ROBERT J. SIMPSON, Professor of Electronic Engineering, University of CentralLancashire", "author_names": [ "Malcolm S Woolfson" ], "corpus_id": 115920465, "doc_id": "115920465", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Book Review: Modern Electronic Communication", "venue": "", "year": 1993 }, { "abstract": "Digital Signal Transmission: C. C. BISSELL and D. A. CHAPMAN (Cambridge University Press, 1992,321 pp. PS15.95, $34.95paperback, PS45, $79.95hardback) The subject of digital transmission is large and complex and a thorough treatment of the topic requires considerable detailed discussion and involves significant mathematical theory. However most students at undergraduate level require an easily readable text with the mathematical content kept to the bare essentials. This book is aimed at second and third year undergraduate students and practising engineers that require updating in modern techniques. The mathematical theory has been kept to a minimum and the standard mathematical results are presented in appendices. A large portion of the text has been derived from the authors' contributions to the Open University course on Digital Telecommunications and perhaps as a consequence the text is written in a style which makes it very suitable for self study. The book only considers a limited number of topics in depth and places the emphasis on the engineering aspects of digital transmission and interpretation of mathematical models. The chapters are grouped into three parts. Part I considers models and discusses continuous and discrete time signals and systems as well as random signals and noise. Part 2 describes processes and explains details of the pulses that are used for digital transmission, and it also discusses line codes and channel codes, including scrambling, block codes and convolution coding. The final part of the book is devoted to digital transmission over the public switched telephone network. The topics considered in this part are relevant analogue and digital signal sources, coding techniques, digital transmission hierarchies and the features of an optical fibre link. I found this an interesting and useful book which has been written with the undergraduate student very much in mind. It is very appropriate for use in universities as a student text for the typical telecommunication undergraduate course. ROBERT J. SIMPSON, Professor of Electronic Engineering, University of CentralLancashire", "author_names": [ "Trevor M Benson" ], "corpus_id": 116606836, "doc_id": "116606836", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Book Review: Fiber Optic Communication Systems", "venue": "", "year": 1993 } ]

[ { "abstract": "Abstract Automated visual inspection is an image processing technique for quality control and production line automation. This paper reviews various optical inspection approaches in the semiconductor industry and categorize the previous literatures by the inspection algorithm and inspected products. The vision based algorithms that had been adopted in the visual inspection systems include projection methods, filtering based approaches, learning based approaches, and hybrid methods. To discuss about the practical applications, the semiconductor industry covers the manufacturing and production of wafer, thin film transistor liquid crystal displays, and light emitting diodes. To improve the yield rate and reduce manufacturing costs, the inspection devices are widely installed in the design, layout, fabrication, assembly, and testing processes of production lines. To achieve a high robustness and computational efficiency of automated visual inspection, interdisciplinary knowledge between precision manufacturing and advanced image processing techniques is required in the novel system design. This paper reviews multiple defect types of various inspected products which can be referenced for further implementations and improvements.", "author_names": [ "Szu-Hao Huang", "Ying-Cheng Pan" ], "corpus_id": 32383127, "doc_id": "32383127", "n_citations": 154, "n_key_citations": 4, "score": 1, "title": "Automated visual inspection in the semiconductor industry: A survey", "venue": "Comput. Ind.", "year": 2015 }, { "abstract": "The effective decision of continuous increase of technological level and the economic efficiency of semiconductor manufacturing demands the adequate statistical models describing distribution of defects and yield. In the paper, motivated by semiconductor manufacturing, we study a problem of data association of condition of technological process.This work presents a yield analysis method using basic operating defect information to statistically define essential original causes of yield loss in semiconductor manufacturing. Using simple statistics on yield loss percent, this method provides the process list on influence of yield loss. This tool is also applied to selection of the most effective inspection tool. Complete understanding of the inspection equipment is not required for its statement. Analysis by sizes and types of defects provides decision and elimination of defects.The paper aspires to offer the model of yield loss percent distributions in semiconductor manufacturing based on estimations of operator technologists directly in the IC manufacturing. A wide range of alternative modeling approaches has been carried out up to now. Also the large variety of criteria and tests has been used to estimate of the forecast accuracy on various volume of dataset. Results offer a robust comparative tools if we have a full source of the information for process. The described method could be especially useful tool for the persons making decision. Besides, models allow to receive valuable forecasts for turning points when various improvements implemented into technological process. It allows to predict somewhat result of process and to catch a trend. This model may be extended for the yield forecasting using a similar approach.", "author_names": [ "Oleg V Stukach", "Raushan Zh Aimagambetova" ], "corpus_id": 201068780, "doc_id": "201068780", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Model of the Yield Loss Factors Based on Survey Analysis for the Integrated Circuits Manufacturing", "venue": "2019 International Seminar on Electron Devices Design and Production (SED)", "year": 2019 }, { "abstract": "The present invention provides a method of manufacturing a semiconductor device inspection apparatus, the inspection system, inspection methods, and inspection of the semiconductor device is completed, the inspection apparatus of the semiconductor device to the output signal of the semiconductor inspection apparatus, comprising: monitor means, that performs signal detection on the monitor line; a plurality of test circuits that are connected to the monitor line. Each test circuit includes: a support member of the semiconductor device, which semiconductor device can be provided, having a signal terminal and a signal input from the semiconductor device provided; a first resistor which is connected between the signal terminal and the monitor circuit; selector terminals; a first diode, which is the terminal side of the selector serves as a cathode is connected between the signal terminal and the selector terminal.", "author_names": [ "" ], "corpus_id": 108362182, "doc_id": "108362182", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The method of producing a semiconductor device testing apparatus, the test system, test method, and a semiconductor device of the completion of the survey", "venue": "", "year": 2012 }, { "abstract": "In many industrial, medical and scientific image processing applications, various feature and pattern recognition techniques are used to match specific features in an image with a known template. Despite the capabilities of these techniques, some applications require simultaneous analysis of multiple, complex, and irregular features within an image as in semiconductor wafer inspection. In wafer inspection discovered defects are often complex and irregular and demand more human like inspection techniques to recognize irregularities. By incorporating neural network techniques such image processing systems with much number of images can be trained until the system eventually learns to recognize irregularities. The aim of this project is to develop aframework of a machine learning system that can produce caption to accurately describe images. Such a system finds application in semiconductor industry, biomedical field where microscopy for identifying different cell types and analysis of tumour growth etc. Also such systems help visually impaired people in understanding pictures. They can be used for providing alternate text for images in parts of the world where mobile connections are slow and making it easier for everyone to search on Google for images are also possible.", "author_names": [ "Gnana Sheela" ], "corpus_id": 212474832, "doc_id": "212474832", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Survey on Feature Extraction of Images for Appropriate Caption Generation", "venue": "", "year": 2016 }, { "abstract": "Optically Pumped Semiconductor Lasers OPSLs have been introduced in 2001. Their unique features such as power scalability and wavelength flexibility, their excellent beam parameters, power stability and reliability opened this pioneering technology access to a wide range of applications such as flow cytometry, confocal microscopy, sequencing, medical diagnosis and therapy, semiconductor inspection, graphic arts, forensic, metrology. This talk will introduce the OPSL principles and compare them with ion, diode and standard solid state lasers. It will revue the first 10 years of this exciting technology, its current state and trends. In particular currently accessible wavelengths and power ranges, frequency doubling, ultra narrow linewidth possibilities will be discussed. A survey of key applications will be given.", "author_names": [ "Christian Kannengiesser", "Vasiliy G Ostroumov", "Volker Pfeufer", "Wolf Seelert", "Christoph Simon", "Rudiger von Elm", "Andreas Zuck" ], "corpus_id": 122294290, "doc_id": "122294290", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Ten years optically pumped semiconductor lasers: review, state of the art, and future developments", "venue": "LASE", "year": 2010 }, { "abstract": "This paper presents some of the techniques used to introduce simulation of semiconductor fabrication processes to undergraduate electrical engineering students at the American University of Sharjah. Students use Silvaco Athena process simulator and Atlas device simulator to perform experiments on semiconductor fabrication processes. Simulation results are compared with the theoretically expected results. As semiconductor process simulation tools can respond to user initiated actions in real time, breaking the process at any point of time permits the visual inspection of the intermediate and final results. Therefore, these tools are found to be effective in the learning process. A survey is conducted at the end of each semester to assess the ability of the students to perform semiconductor process simulation. Experience indicates that there is considerable increase in the confidence level of the students in terms of their understanding of semiconductor processes and devices.", "author_names": [ "M Narayanan", "Hasan Al-Nashash" ], "corpus_id": 15295408, "doc_id": "15295408", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Introducing undergraduate students to simulation of semiconductor doping techniques", "venue": "Comput. Electr. Eng.", "year": 2009 }, { "abstract": "A cross sectional survey of semiconductor factories was conducted to identify the ergonomic risk factors in the work processes, the prevalence of body pain among workers, and the relationship between body pain and work processes. A total of 906 women semiconductor workers took part in the study. In wafer preparation and polishing, a combination of lifting weights and prolonged standing might have led to high pain prevalences in the low back (35.0% wafer preparation, 41.7% wafer polishing) and lower limbs (90.0% wafer preparation, 66.7% wafer polishing) Semiconductor front of line workers, who mostly walked around to operate machines in clean rooms, had the lowest prevalences of body pain. Semiconductor assembly middle of line workers, especially the molding workers, who did frequent lifting, had high pain prevalences in the neck/shoulders (54.8% and upper back (43.5 In the semiconductor assembly end of line work section, chip inspection workers who were exposed to prolonged sitting without back support had high prevalences of neck/shoulder (62.2% and upper back pain (50.0% while chip testing workers who had to climb steps to load units had a high prevalence of lower limb pain (68.0% Workers in the assembly of electronic components, carrying out repetitive tasks with hands and fingers, and standing in awkward postures had high pain prevalences in the neck/shoulders (61.5% arms (38.5% and hands/wrists (30.8%", "author_names": [ "Heng Leng Chee", "Krishna Gopal Rampal", "Abherhame Chandrasakaran" ], "corpus_id": 834943, "doc_id": "834943", "n_citations": 27, "n_key_citations": 6, "score": 0, "title": "Ergonomic risk factors of work processes in the semiconductor industry in Peninsular Malaysia.", "venue": "Industrial health", "year": 2004 }, { "abstract": "In todays Semiconductor Manufacturing Industry it is becoming more difficult to utilize the human operator as the visual process control vehicle so as to cost effectively achieve statistical process defect goals. Machine vision continues to make inroads cost effectively improving manufacturing visual inspection requirements driving and sustaining desired process control capabilities. This paper will attempt to survey the attributes of automatic visual process monitoring within the Motorola Semiconductor Assembly Manufacturing environment. Such factors as defect control objectives inspection requirements vision engine platform application engineering and long term application maintenance all of which contribute to the costeffectiveness of the automatic visual inspection task.", "author_names": [ "Christopher J LeBeau" ], "corpus_id": 109728061, "doc_id": "109728061", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Machine vision platform requirements for successful implementation and support in the semiconductor assembly manufacturing environment", "venue": "Other Conferences", "year": 1991 }, { "abstract": "Abstract A study was undertaken to determine the feasibility of obtaining high reliability devices for long term space missions and military applications by imposing and monitoring additional process quality controls and screening procedures on standard commercial production lines. A survey of more than a dozen semiconductor manufacturers indicated that the following reliability areas are not adequately controlled: metallization, wire bonding, loose conductive particles and ceramic packages sealed by low melting point glasses. Wide variations were found in the manner in which the bond strength test is carried out. Methods were studied to institute SEM inspection and a more rigorous bond strength test on the production lines, coupled with wafer and bonder traceability. This report surveys reliability problems caused by defects in semiconductor devices and their control.", "author_names": [ "Alan G Stanley" ], "corpus_id": 108249620, "doc_id": "108249620", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Procurement of Reliable Semiconductor Devices for Military Space Applications", "venue": "", "year": 1972 }, { "abstract": "To be productive and profitable in a modern semiconductor fabrication environment, large amounts of manufacturing data must be collected, analyzed, and maintained. This data is increasingly being used to design new processes, control and maintain tools, and to provide the information needed for rapid yield learning and prediction. Towards this end, a significant level of investment has been made over the past decade to bring to maturity viable technologies for Automatic Defect Classification (ADC) as a means of automating the recognition and analysis of defect imagery captured during in line inspection and off line review. ADC has been developed to provide automation of the tedious manual inspection processes associated with defect review. Although significant advances have been achieved in the capabilities of ADC systems today, concerns continue to persist regarding effective integration, maintenance, and usability of commercial ADC technologies. During the summer of 2001, the Oak Ridge National Laboratory and International SEMATECH performed an industry survey of eight major semiconductor device manufacturers to address the issues of ADC integration, usability, and maintenance for the various in line inspection and review applications available today. The purpose of the survey was to determine and prioritize those issues that inhibit the effective adoption, integration, and application of ADC technology in today's fabrication environment. In this paper, we will review the various ADC technologies available to the semiconductor industry today and discus the result of the survey.", "author_names": [ "Kenneth W Tobin", "Fred Lakhani", "Thomas P Karnowski" ], "corpus_id": 109651152, "doc_id": "109651152", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Industry survey of automatic defect classification technologies, methods, and performance", "venue": "SPIE Advanced Lithography", "year": 2002 } ]

[ { "abstract": "Preface.Acknowledgements.Glossary of Abbreviations.Glossary of Symbols.1. An Introduction to Optical Communication Systems.2. Principles of Distributed Feedback Semiconductor Laser Diodes: Coupled Wave Theory.3. Structural Impacts on the Solutions of Coupled Wave Equations: An Overview.4. Transfer Matrix Modelling in DFB Semiconductor Lasers.5. Threshold Analysis and Optimization of Various DFB LDs Using the Transfer Matrix Method.6. Above Threshold Characteristics of DFB Laser Diodes: A TMM Approach.7. Above Threshold Analysis of Various DFB Lase r Structures Using the TMM.8. Circuit and Transmission Line Laser Modelling (TLLM) Techniques.9. Analysis of DFB Laser Diode Characteristics Based on the Transmission Line Modelling (TLLM).10. Wavelength Tunable Optical Filters Based on DFB Laser Structures.11. Other Wavelenght Tunable Optical Filters Based on the DFB Laser Structure.12. Conclusion, Summary and Suggestions.Index.", "author_names": [ "Hooshang Ghafouri-Shiraz" ], "corpus_id": 106760141, "doc_id": "106760141", "n_citations": 143, "n_key_citations": 11, "score": 1, "title": "Distributed feedback laser diodes and optical tunable filters", "venue": "", "year": 2003 }, { "abstract": "A photonic wavelength division switching system using semiconductor tunable wavelength filters is proposed. A switching system using wavelength switches and multistage switching networks is discussed. A crucial point in developing this switching system is to achieve a large number of wavelength division channels. The potential of 100 wavelength division channels in such switching systems is estimated, based on InP optical integrated circuits. A wavelength network synchronization which permits the network to utilize such a large number of wavelength division channels without wavelength misalignment and drift is proposed. An eight channel wavelength division switching experiment, using phase shift controlled distributed feedback laser diodes as tunable wavelength filters, is reported.", "author_names": [ "Shuji Suzuki", "Makoto Nishio", "Takahiro Numai", "Masahiko Fujiwara", "Masaki Itoh", "S Murata", "Naoki Shimosaka" ], "corpus_id": 111007700, "doc_id": "111007700", "n_citations": 34, "n_key_citations": 2, "score": 0, "title": "A photonic wavelength division switching system using tunable laser diode filters", "venue": "", "year": 1990 }, { "abstract": "A photonic wavelength division switching system using semiconductor tunable wavelength filters is proposed. Wavelength switches and multistage switching networks are used. The potential of 100 wavelength division channel achievement in switching systems is estimated, based on InP optical integrated circuits. A wavelength network synchronization method is proposed, which will enable the network to utilize such a large number of wavelength division channels without wavelength misalignment and drift. An eight channel wavelength division switching experiment, using phase shift controlled distributed feedback laser diodes as tunable wavelength filters, is reported.<ETX>", "author_names": [ "Shuji Suzuki", "Makoto Nishio", "Takahiro Numai", "Masahiko Fujiwara", "Masaki Itoh", "S Murata", "Naoki Shimosaka" ], "corpus_id": 60491639, "doc_id": "60491639", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "A photonic wavelength division switching system using tunable laser diode filters", "venue": "IEEE International Conference on Communications, World Prosperity Through Communications,", "year": 1989 }, { "abstract": "OTHER PUBLICATIONS Broeke et al. \"Monolithical integration of semiconductor optical amplifiers and passive mode filters fro low facet reflectivity\" 2001 IEEE/LEOS Symposium Benelux Chapter. Dec. 3, 2001. S. D. DeMars, A. Schoenfelder, V. Wong, and R. J. Lang, \"Optical Properties of Angled Grating Distributed Feedback Lasers.\" IEEE 16th ISLC Conference Digest, 1998, pp. 57 58. V. N. Gulgazov, H. Zhao, D. Nam, J. S. Major, and T. L. Koch \"Tunable high power AlGaAs distributed Bragg reflector Laser diodes\" Electron. Lett. 1997, 33, (1) pp. 58 59. (Continued) Primary Examiner Armando Rodriguez (74) Attorney, Agent, or Firm Allen, Dyer, Doppelt, Milbrath Gilchrist, P.A.", "author_names": [ "John S Major", "S O'brien", "V Gulgazov", "Dave Welch", "Robert J Lang", "Victor V Rossin", "Erik P Zucker", "Matthew G Peters", "Matthew Everett", "Bruno D Acklin" ], "corpus_id": 150367614, "doc_id": "150367614", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "SINGLE SPATAL MODE OUTPUT MULT MODE INTERFERENCE LASER DODE WITH EXTERNAL CAVITY", "venue": "", "year": 2017 }, { "abstract": "Over the past 20 years, research into Gallium Nitride (GaN) has evolved from LED lighting to Laser Diodes (LDs) with applications ranging from quantum to medical and into communications. Previously, off the shelf GaN LDs have been reported with a view on free space and underwater communications. However, there are applications where the ability to select a single emitted wavelength is highly desirable, namely in atomic clocks or in filtered free space communications systems. To accomplish this, Distributed Feedback (DFB) geometries are utilised. Due to the complexity of overgrowth steps for buried gratings in III Nitride material systems, GaN DFBs have a grating etched into the sidewall to ensure single mode operation, with wavelengths ranging from 405nm to 435nm achieved. The main motivation in developing these devices is for the cooling of strontium ions (Sr+ in atomic clock applications, but their feasibility for optical communications have also been investigated. Data transmission rates exceeding 1 Gbit/s have been observed in unfiltered systems, and work is currently ongoing to examine their viability for filtered communications. Ultimately, transmission through Wavelength Division Multiplexing (WDM) or Orthogonal Frequency Division Multiplexing (OFDM) is desired, to ensure that data is communicated more coherently and efficiently. We present results on the characterisation of GaN DFBs, and demonstrate their capability for use in filtered optical communications systems.", "author_names": [ "Steffan Gwyn", "Scott Watson", "Shaun Viola", "Giovanni Giuliano", "Thomas J Slight", "Szymon Stanczyk", "Szymon Grzanka", "Amit Yadav", "Kevin E Docherty", "Edik U Rafailov", "Piotr Perlin", "Stephen P Najda", "Mike Leszczynski", "Anthony E Kelly" ], "corpus_id": 208346062, "doc_id": "208346062", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "GaN based distributed feedback laser diodes for optical communications", "venue": "Fourth International Conference on Applications of Optics and Photonics", "year": 2019 }, { "abstract": "In this paper, the amplified spontaneous emission (ASE) intensity of a distributed feedback laser diode (DFB LD) amplified by a semiconductor optical amplifier (SOA) is calculated, and the signal to spontaneous emission ratio (SSER) is investigated assuming a wavelength tunable laser. Based on a formulization appropriate for an active layer under a low excitation, the theoretical limit of the SSER of the SOA is obtained, and the SSER including the ASEs from both the DFB LD and the SOA is numerically calculated. The side mode suppression ratio (SMSR) taking the spectral distribution into consideration is also calculated by expanding the same method.", "author_names": [ "Kazuaki Kiyota" ], "corpus_id": 220314962, "doc_id": "220314962", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Theoretical Calculation of Amplified Spontaneous Emission in a Distributed Feedback Laser Diode Assisted by a Semiconductor Optical Amplifier", "venue": "IEEE Journal of Quantum Electronics", "year": 2020 }, { "abstract": "A novel widely tunable single passband microwave photonic filter (MPF) is proposed and experimentally demonstrated, which is based on a carrier suppressed double sidebands (CS DSB) optical signal injected into an distributed feedback (DFB) laser. A polarization modulator (PolM) and a polarization beam splitter (PBS) are exploited to generate the CS DSB optical signal. When the CS DSB optical signal is injected into the DFB laser, due to the frequency selective gain feature of optical injected DFB laser, one sideband of the CS DSB optical signal is selected and amplified. Beating the amplified sideband with the optical carrier, the gain spectrum of the DFB laser is mapped to the frequency response of the MPF. The MPF can be tuned by adjusting the wavelength of the DFB laser. Experiment results show that the MPF can be tuned from 0 to 40 GHz by changing the working temperature of the DFB laser.", "author_names": [ "Yuandong Li", "Jiling Zheng", "Peng Xiang", "Huatao Zhu", "Zhou Hua", "Tao Pu", "Zhouming Feng", "Meng Hu", "Yuan Liu" ], "corpus_id": 181431211, "doc_id": "181431211", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Single passband microwave photonic filter with widely tuning range based on optical injected distributed feedback semiconductor laser", "venue": "Optical Review", "year": 2019 }, { "abstract": "We investigate integrated mode locked laser diodes with distributed Bragg reflectors fabricated in the JePPIX Oclaro indium phosphide photonics platform. The optical and radio frequency (RF) characteristics of passively mode locked lasers with and without monolithically integrated feedback cavities were measured and compared. The RF linewidth of the mode locked laser could be reduced by integrating an optical feedback cavity of a particular length and a tunable magnitude of feedback. A maximum linewidth reduction factor of 1.9 was observed near the onset of mode locking, but increasing the laser optical power tended to lead to unstable operation. Increasing the drive current of the design without feedback also reduced the RF linewidth. A reduction factor of 7.6 was observed.", "author_names": [ "Torrey Thiessen", "Joyce K S Poon" ], "corpus_id": 11396809, "doc_id": "11396809", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "20 GHz Mode Locked Laser Diodes With Integrated Optical Feedback Cavities in a Generic Monolithic InP Photonics Platform", "venue": "IEEE Photonics Journal", "year": 2017 }, { "abstract": "This paper demonstrates the interrogation of a fiber Bragg grating with a flat topped reflection spectrum centred on 1649.55 nm using only a single mode tunable 1651.93 nm semiconductor laser and a fiber ring resonator. The Bragg shift is accurately measured with the fiber optic ring resonator that has a free spectral range (FSR) of 0.1008 GHz and a broadband photo detector. Laser wavelength modulation and harmonic detection are used to transform the gentle edges of the flat topped FBG spectrum into prominent leading and trailing peaks, either of which can be used to accurately measure spectral shifts of the FBG reflection spectrum with a resolution of 0.9 pm. A Raspberry Pi based low cost embedded processor is used to measure the temperature induced spectral shifts over the range 30degC 80degC. The shift was linear with a temperature sensitivity of 12.8 pm/degC. This technique does not use an optical spectrum analyzer at any stage of its design or operation. The laser does not need to be pre characterized either. This technique can be readily extended to all types of tunable diode lasers and is ideally suited for compact field instruments.", "author_names": [ "Anirban Roy", "Arup Lal Chakraborty", "Chandan Kumar Jha" ], "corpus_id": 28068257, "doc_id": "28068257", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Fiber Bragg grating interrogation using a wavelength modulated 1651 nm tunable distributed feedback laser and a fiber ring resonator for wearable biomedical sensors", "venue": "2017 25th Optical Fiber Sensors Conference (OFS)", "year": 2017 }, { "abstract": "We report on the modeling, growth, processing, characterization and integration in a gas detection setup of side wall corrugated distributed feed back antimonide diode lasers emitting at 2.28 and 2.67 mm. The laser structures were grown by molecular beam epitaxy on GaSb substrate. Ridge lasers were fabricated from the grown wafers according to the following process: a second order Bragg grating was defined on the sides of the ridges by interferometric lithography, optical lithography and etched in a Cl based inductively coupled plasma reactor. The devices exhibit a power reaching 40 mW, a side mode suppression ratio better than 28 dB and a tuning range of 3 nm at room temperature. One of these devices was successfully integrated in a tunable diode laser absorption spectroscopy setup, thus demonstrating that they are suitable for gas analysis.", "author_names": [ "Quentin Gaimard", "Alexandre Larrue", "Meriam Triki", "Brice Adelin", "Tong Nguyen-ba", "Yves Rouillard", "Olivier Gauthier-Lafaye", "R Teissier", "Aurore Vicet" ], "corpus_id": 98758619, "doc_id": "98758619", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "2.2 2.7 mm side wall corrugated index coupled distributed feedback GaSb based laser diodes", "venue": "", "year": 2015 } ]

[ { "abstract": "Overall solar energy conversion efficiencies of at least 0.8 percent, somewhat greater than those previously reported, have been obtained in the photocatalytic production of hydrogen using TiO/sub 2/ semiconductor electrodes prepared by heat treatment of titanium metal foils. A shift in the threshold frequency for hydrogen evolution toward energies slightly lower than the 3.02 eV bandgap of TiO/sub 2/ was observed for some of these electrodes. This result supports the possibility of utilizing a greater portion of the solar spectrum, thereby increasing overall conversion efficiency even further. A tentative explanation of this shift involves the presence of mixed phases of the titanium oxygen system (Magneli phases) in the semiconducting film.", "author_names": [ "John F Houlihan", "David P Madacsi", "E J Jun Walsh", "L N Mulay" ], "corpus_id": 95419113, "doc_id": "95419113", "n_citations": 53, "n_key_citations": 0, "score": 1, "title": "Improved solar energy conversion efficiencies for the photocatalytic production of hydrogen via TiO2 semiconductor electrodes", "venue": "", "year": 1976 }, { "abstract": "Abstract Hydrogen (H2) production via photocatalytic water splitting is one of the most promising technologies for clean solar energy conversion to emerge in recent decades. The achievement of energy production from water splitting would mean that we could use water as a fuel for future energy need. Among the various photocatalytic materials, titanium dioxide (TiO2) is the dominant and most widely studied because of its exceptional physico chemical characteristics. Surface decoration of metal/non metal on TiO2 nanoparticles is an outstanding technique to revamp its electronic properties and enrich the H2 production efficiency. Metal dopants play a vital role in separation of electron hole pairs on the TiO2 surface during UV/visible/simulated solar light irradiation. In this paper, the basic principles, photocatalytic reactor design, kinetics, key findings, and the mechanism of metal doped TiO2 are comprehensively reviewed. We found that Langmuir Hinshelwood kinetic model is commonly employed by the researchers to demonstrate the rate of H2 production. Copper (Cu) gold (Au) and platinum (Pt) are the most widely studied dopants for TiO2, owing to their superior work function. The metal dopants can amplify the H2 production efficiency of TiO2 through Schottky barrier formation, surface plasmon resonance (SPR) generation of gap states by interaction with TiO2 VB states. The recent advances and important consequences of 2D materials, perovskites, and other novel photocatalysts for H2 generation have also been reviewed.", "author_names": [ "Vignesh Kumaravel", "Snehamol Mathew", "John BartlettJ Bartlett", "Suresh C Pillai" ], "corpus_id": 104392726, "doc_id": "104392726", "n_citations": 284, "n_key_citations": 2, "score": 0, "title": "Photocatalytic hydrogen production using metal doped TiO2: A review of recent advances", "venue": "Applied Catalysis B: Environmental", "year": 2019 }, { "abstract": "Photocatalysis is a promising methodology for hydrogen production. It involves the use of an unlimited source of energy, sunlight, and a semiconductor material to split the water with zero carbon emissions. This Master's thesis reports high efficiencies in terms of hydrogen production via water splitting using 2.0v/v% ethanol as scavenger, platinum and palladium as noble metals on TiO2 photocatalysts at three metal loadings (1.0, 2.5 and 5.0wt% Both near UV and visible light were used in the studies developed. These photocatalysts were synthetized using a sol gel method whose morphological properties were enhanced due to the presence of soft template precursors. Experiments were carried out in the Photo CREC Water reactor II. This novel unit offers symmetrical irradiation allowing precise irradiation measurements for macroscopic energy balances. In all cases hydrogen production followed a zero order reaction. Optimal quantum efficiencies were achieved under near UV light, reaching a significant 30.8% The doped TiO2 photocatalysts were also studied under visible light obtaining a valuable 1.2% of quantum efficiency. In order to achieve this, the prepared semiconductors were photoreduced and activated with near UV light.", "author_names": [ "Bianca Rusinque" ], "corpus_id": 105572699, "doc_id": "105572699", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Hydrogen Production by Photocatalytic Water Splitting Under Near UV and Visible Light Using Doped Pt and Pd TiO2", "venue": "", "year": 2018 }, { "abstract": "Abstract Here we report a versatile strategy based on the use of BaO as an electron promoter to boost the photocatalytic activity of TiO2 based, Pd supported photocatalysts for hydrogen production from water splitting. Pd BaO nanoparticles were deposited on the TiO2 surface by simple chemical reduction method using NaBH4 as reductant. The as synthesized Pd BaO/TiO2 photocatalysts showed a remarkably high performance in hydrogen production, approximately 29.6 mmol g 1h 1 using an ethanol water mixture (5% ethanol and 95% water) which is two times higher than Pd/TiO2 photocatalyst, where the latter is already regarded as the most active metal based TiO2 photocatalysts for H2 production. This high hydrogen production efficiency was attributed to the inherent high catalytic activity of palladium nanoparticles and electronic promotional effect of BaO. The Ba (in the form of BaO) greatly enhanced the electron transfer from the semiconductor conduction band to Pd centers by raising the Fermi level of TiO2 during photo irradiation. Most importantly, Pd is present exclusively in zero oxidation state, which is ideal for proton reduction in the as prepared photocatalysts due to close proximity of highly electropositive BaO. The structural morphologies and mechanistic aspects of the Pd BaO/TiO2 photocatalysts are addressed by using UV Vis/DRS, XRD, TEM, and XPS characterization techniques.", "author_names": [ "Ejaz Hussain", "Imran Majeed", "Muhammad Amtiaz Nadeem", "Azhar Iqbal", "Yuxiang Chen", "Mohammad Choucair", "Rongchao Jin", "Muhammad Arif Nadeem" ], "corpus_id": 106204048, "doc_id": "106204048", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Remarkable effect of BaO on photocatalytic H2 evolution from water splitting via TiO2 (P25) supported palladium nanoparticles", "venue": "Journal of Environmental Chemical Engineering", "year": 2019 }, { "abstract": "AbstractPhotocatalytic water splitting using particulate semiconductor materials has been studied as a simple means of hydrogen production. However, there are still many obstacles to the development of complete, practical and renewable solar hydrogen production processes. This review discusses particulate photocatalyst systems intended for large scale solar hydrogen production via water splitting, focusing on their current status and potential impact. The cost and efficiency targets for solar to fuel conversion on a practical scale are also reviewed, based on the maximum allowable cost of solar hydrogen production systems, which has been estimated to be US$102 m 2, at most. Particulate photocatalyst material design principles are discussed, using efficient oxide photocatalysts as examples. Approaches to constructing photocatalytic reactors extensible to large areas are also introduced. Finally, challenges related to the development of efficient and inexpensive photocatalyst systems and potentially useful analytical methods are outlined.Photocatalytic water splitting with particulate semiconductors represents a promising strategy for the generation of hydrogen as a solar fuel. This review covers recent advances in the development of reaction systems and photocatalysts towards the scale up of this technology, emphasizing at the same time the challenges to overcome.", "author_names": [ "Takashi Hisatomi", "Kazunari Domen" ], "corpus_id": 139539126, "doc_id": "139539126", "n_citations": 325, "n_key_citations": 0, "score": 0, "title": "Reaction systems for solar hydrogen production via water splitting with particulate semiconductor photocatalysts", "venue": "Nature Catalysis", "year": 2019 }, { "abstract": "The production of cleaner fuels from renewable and safer energy resources are highly demanding to mitigate energy crises and global warming. In this study, the use of cleaner photo technology for selective and enhanced CO2 reduction to fuels over nickel (Ni) modified titanium dioxide (TiO2) dispersed in structured montmorillonite (MMT) nanoclay for photocatalytic CO2 hydrogen conversion via reverse water gas shift (RWGS) reaction has been investigated. The catalyst samples, prepared by a single step sol gel method, were characterised by XRD, FTIR, FESEM and UV visible spectroscopy. XRD results revealed reduced in TiO2 crystallite size with Ni and MMT loading and produced anatase phase of TiO2. MMT is found efficient for the enhanced dispersion of TiO2 while Ni promoted efficient charges separation with hindered recombination rate over the structured MMT/TiO2 nanocomposite. The photoactivity of Ni/TiO2 MMT composite for CO2 reduction was conducted in a continuous flow photoreactor using hydrogen as the reducing agent. The main products detected were CO and CH4 with appreciable amounts of C2H4, C2H6 and C3H6 hydrocarbons. The maximum yield of CO produced as the main product over 3 wt% Ni 10 wt% MMT/TiO2 catalyst was 9,429umole/g cat, 209 fold higher than the amount of CO detected over the pure TiO2. Evidently, Ni promoted TiO2 photocatalytic activity, while MMT is favourable for improved dispersion of Ni/TiO2 catalyst. The dynamic and selective CO evolution was evidently due to efficient light distribution, enlarged active surface area and efficient charges separation with their hindered recombination rate by Ni and MMT. The stability of Ni/TiO2 dispersed over MMT sustained over the irradiation time. With the use of green nanocomposite catalyst, CO2 can be efficiently converted to cleaner fuels with all sustainable systems.", "author_names": [ "Tahir Beenish", "Tahir Muhammad", "Nor Aishah Saidina Amin" ], "corpus_id": 55689848, "doc_id": "55689848", "n_citations": 5, "n_key_citations": 1, "score": 0, "title": "Photocatalytic co2 hydrogen conversion via rwgsr over ni/tio2 nanocatalyst dispersed in layered mmt nanoclay", "venue": "", "year": 2018 }, { "abstract": "The production of carbon nanotubes (CNTs) is usually carried out either via catalytic decomposition of methane or by recrystallization of bio char species obtained by pyrolysis of solid wastes. Both techniques are generally executed at high temperatures and consume long time. Thus, these two methodologies are not considered to be economically feasible. This research work reports a facile and cost effective new route for the generation of CNTs via photocatalytic conversion of water to hydrogen. Specifically, water splitting photochemical reaction using a metal organic framework (Cr MIL 101) and TiO2 nanoparticles was demonstrated. The coupling of the aforementioned semiconductors, as novel matrices, to improve the photocatalytic reactivity toward hydrogen production in the presence of methanol, as a hole scavenger, under visible light was performed. The results revealed the high yield evolution of H2 showing a maximum purity of 99.3% with the in situ formation of carbon nanotubes over the surface of the Cr MIL 101/TiO2 binary system that was obtained by sonication. The use of this binary photocatalyst, however, as a physical mix could produce nano carbon species while simultaneously producing hydrogen rich syngas. The production of H2 gas that was simultaneously stored was noted when Cr MIL 101 was used individually as a photocatalyst. These data provide new advances in the field of water splitting by introducing promising candidate materials for the production of pure hydrogen as a clean fuel.", "author_names": [ "Rasha S Mohamed", "Amal A Al Kahlawy", "Ahmed M A El Naggar", "Heba M Gobara" ], "corpus_id": 213560127, "doc_id": "213560127", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Innovative approach for the production of carbon nanotubes (CNTs) and carbon nanosheets through highly efficient photocatalytic water splitting into hydrogen using metal organic framework (MOF) nano TiO2 matrices as novel catalysts", "venue": "", "year": 2020 }, { "abstract": "Abstract The photocatalytic hydrogen evolution on inorganic semiconductors has been studied for several decades. However, the conversion efficiency of solar energy is still poor caused by the recombination of photo generated electron hole pairs. Semiconductors metal organic frameworks (MOFs) hybrid photocatalysts are being regarded as promising candidates due to large surface area and porosity. Here we reported the coordinative integration of a composite material with efficient capacity of H2 evolution driven by solar light, namely TiO2@ZIF 8, made up of titanium dioxide hollow nanospheres (TiO2 HNPs) externally decorated with zeolitic imidazolate framework 8 (ZIF 8) via a facile sonochemical route. The resulting composite demonstrates the high dispersion of ZIF 8 on the surface of TiO2 HNPs and this kind of close connection makes for an efficient photocatalyst through the synergistic effect. Up to 50.89% of apparent quantum efficiency (AQE) the hybrid double shell HNPs exhibits 3.5 times higher H2 evolution rate (HER) than the bare TiO2 HNPs under solar light and shows good stability and recyclability. It is further proposed by photoluminescence spectra and optoelectronic measurement that the remarkably enhanced photocatalytic activity of TiO2@ZIF 8 is not only attributed to the efficient charge separation with electron injection from ZIF 8 to TiO2 HNPs, but also more active reaction sites provided by cavity structure of ZIF 8. Overall, this work exemplifies that surface engineering of semiconductors with MOFs is a great strategy to achieve advanced photocatalytic performance for solar energy conversion.", "author_names": [ "Ming Yang Zhang", "Qigao Shang", "Yuqi Wan", "Qingrong Cheng", "Guiying Liao", "Zhi-quan Pan" ], "corpus_id": 105751206, "doc_id": "105751206", "n_citations": 100, "n_key_citations": 1, "score": 0, "title": "Self template synthesis of double shell TiO2@ZIF 8 hollow nanospheres via sonocrystallization with enhanced photocatalytic activities in hydrogen generation", "venue": "Applied Catalysis B: Environmental", "year": 2019 }, { "abstract": "Solar to chemical energy conversion is a challenging photochemical reaction for renewable energy storage. In recent decades, photocatalytic H2 evolution has been studied extensively. TiO2 is a well established semiconductor in the field of photocatalytic H2 production; however, its low efficiency for solar energy utilization, and high photocarrier recombination rate, restrict its photocatalytic efficiency. Here, a series of K intercalated g C3N4 modified TiO2 nanobelts (TCN Kx) with different dosages of K atoms were fabricated using a hydrothermal method followed by a calcination process. XRD, TEM and XPS tests indicate that a tight interfacial connection is formed between K g C3N4 and the TiO2 nanobelts. DFT calculations indicated that K dopants prefer to be at the interlayer sites of g C3N4, suggesting increased charge transfer efficiency. The H2 production efficiency of the TCN Kx composite materials from water splitting under visible light irradiation was clearly improved. Steady fluorescence spectroscopy and photocurrent measurements confirmed that the improvement in photocatalytic H2 production activity was due to the superior charge separation and electron transfer efficiency of TCN Kx composite materials.", "author_names": [ "Jian Ma", "Wei Zhou", "Xin Tan", "Tao Yu" ], "corpus_id": 3807319, "doc_id": "3807319", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Potassium ions intercalated into g C3N4 modified TiO2 nanobelts for the enhancement of photocatalytic hydrogen evolution activity under visible light irradiation.", "venue": "Nanotechnology", "year": 2018 }, { "abstract": "Increasing CO2 anthropogenic concentration in the atmosphere is surpassing sustainable levels and unambiguously jeopardising the global climate. The main share of CO2 emissions corresponds to the production of energy, currently 17 TW per year. By analysing historical trends on population growth and energy consumption, it is expected that the global energy demand will reach 30 TW by 2050, which in turn will aggravate the stress on the environment. In order to alleviate adverse climate change related consequences, it was agreed to reduce global CO2 emissions. This could be achieved by shifting the current energy system towards a carbon free energy vector, hydrogen. Hydrogen can be obtained from the hydrolysis of water using surplus electricity generated from renewables, without contributing to CO2 emissions. The main drawback to switching from a carbon to a hydrogen based energy system is that H2 is a gas and current technology has evolved around liquid fuels. In order to circumvent this energy transition, hydrogen can be further transformed to liquid fuels via its reaction with CO2. In a polymer electrolyte membrane (PEM) electrolyser, water is oxidised at the anode to oxygen and protons, protons migrate through the membrane to the cathode where they recombine with electrons to form hydrogen. Due to the slow kinetics and multiple reaction steps on the anode compared to the cathode, the oxidation of water to oxygen (or oxygen evolution reaction, OER) is responsible for high overpotentials. Additionally, the anode needs to be made of iridium based catalysts, and because of its low natural abundance, it is essential to develop materials with an efficient Ir usage and to optimise its catalytic activity and stability. This research is divided in two defined themes. The first (chapter 3 to chapter 6) focuses on the optimisation of IrO2 catalysts for the oxygen evolution reaction, necessary half reaction in a PEM water electrolyser for the production of hydrogen. The second (chapter 7) comprises of the optimisation of PdZn catalysts supported on TiO2 for the further transformation of H2, by its reaction with CO2, to solar fuels. In chapters 3 and 4, the effect of the base on the hydrothermal synthesis of unsupported and supported amorphous iridium oxo hydroxides is studied. The hydrothermal synthesis was chosen because it allowed the synthesis of amorphous IrOx materials without the need for heat treatment at high temperature, thus minimising the possible crystallisation and the concomitant decrease in activity towards OER. It was observed that the base plays an important role in tailoring the morphology, surface area and surface hydroxide concentration of IrOx catalysts, and thus it has a direct effect on the catalytic activity and stability. Specifically, the use of Li2CO3 as a base led to a catalyst with porous morphology, higher surface area and higher hydroxide concentration, which this translated to an improved activity and stability towards OER compared to the state of the art catalyst IrO2*2H2O (Premion, Alfa Aesar) In both chapters, heat treatment was proven to hinder the catalytic activity towards OER, presumably as a result of higher crystallinity, the loss of Ir(III) sites and the decrease in hydroxide concentration. In chapter 5, two different IrO2 crystalline structures (rutile and hollandite) were synthesised, characterised and compared as OER catalysts. In accordance with the literature, the transformation of amorphous iridium oxo hydroxide, containing Ir(III)/Ir(IV) sites, to crystalline rutile IrO2, made only of Ir(IV) sites, led to a decrease in catalytic activity and stability. However, the presence of Li2CO3 in the amorphous IrOx catalyst led to the formation of hollandite IrO2 instead of rutile IrO2, with lithium as the host cation within the hollandite channels. Apart from the difference in crystallinity, characterisation on hollandite IrO2 indicates that it was closer in nature to amorphous IrOx than to rutile IrO2. The presence of Ir(III) and Ir(IV) was confirmed by XPS, shorter Ir Ir bond distances and longer Ir O, compared to rutile IrO2, were observed by EXAFS, and comparable OER activity to IrO2 Li2CO3 was detected by LSV. Additionally, the conversion of amorphous IrO2 Li2CO3 to hollandite IrO2 led to improved stability under OER reaction conditions. In order to use iridium more efficiently and to reduce the iridium loading on the electrode, in chapter 6 IrO2 was diluted with a more abundant and economic metal oxide, nickel or copper oxide. Catalysts with a homogeneous metal distribution and with a core shell distribution, concentrating iridium at the surface and the non noble metal oxide at the core, were prepared following a modification of the hydrothermal synthesis method. The synthesis of mixed oxide catalysts with a homogeneous metal distribution led to a decrease in the catalytic activity and the stability of the catalyst, which was proven to be an ineffective synthetic route for considerably decreasing the iridium loading on the electrode. The observed decline in the catalytic performance was attributed to the dissolution of the non noble metal oxide in contact with the reaction media. However, through a core shell distribution, IrOx was concentrated on the surface of the catalyst, whilst the non noble metal remained protected against dissolution inside the nanoparticle core. Following the core shell synthetic approach, the iridium loading on the electrode was successfully halved without impairing the catalytic activity or stability, compared to pure IrO2 Li2CO3. The second part discussed in chapter 7, studied the optimisation of PdZn/TiO2 catalysts prepared by chemical vapour impregnation (CVI) for the CO2 hydrogenation (pre reduction at 400 degC, 1 h, reaction at 250 degC, 20 bar, 30 ml*min 1, 60 H2, 20 CO2, 20 N2) to methanol, as a stable alternative to copper catalysts. The first section of the chapter focused on the Pd to Zn molar ratio in the material, maintaining the palladium loading at 5 wt. Increasing the Pd:Zn molar ratio from (1:1) to (1:5) led to a greater formation of PdZn alloy, which improved CO2 conversion, but without considerably affecting methanol selectivity. The further addition of zinc, as observed for the catalyst with a Pd:Zn molar ratio of (1:10) led to a decrease in the CO2 conversion. This was presumably caused by zinc blocking active sites when in large excess. The atomic proportion of zinc in the PdZn alloy can vary from 40 at. to 60 at. Hence it could be hypothesised that increasing the pre reduction temperature could lead to a higher proportion of zinc within the alloy, which in turn can improve methanol selectivity. In general, increasing the pre reduction temperature from 400 degC to 650 degC led to an increase in the methanol productivity because of improved methanol selectivity, although lower CO2 conversion was observed as a result of particle sintering. However, more interestingly, the CH4 selectivity decreased by one order of magnitude after increasing the pre reduction treatment from 400 degC to 650 degC, simultaneously with the transformation of ZnO and TiO2 to rhombohedral ZnTiO3. This lead to the hypothesis that the PdZn TiO2 interphase is responsible for methane production. To prove this hypothesis, PdZn/ZnTiO3 and Pd/ZnTiO3 catalysts were prepared by CVI, after pre reduction at 400 degC. PdZn alloy formation was confirmed by XRD on both systems, indicating that Zn in the ZnTiO3 phase can migrate out of the lattice to form PdZn. Thus, the PdZn TiO2 interface was generated in Pd/ZnTiO3 but not in PdZn/ZnTiO3. When tested for CO2 hydrogenation to methanol, the formation of methane on the former catalyst and its absence on the latter corroborated the formulated hypothesis that PdZn TiO2 acts as the active site for CH4 formation.", "author_names": [ "Jonathan Ruiz Esquius" ], "corpus_id": 203510756, "doc_id": "203510756", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Catalysis to produce solar fuels from the production of hydrogen via water splitting, to hydrogen conversion to methanol by its reaction with CO2", "venue": "", "year": 2019 } ]

[ { "abstract": "In the quest for higher performance, the dimensions of field effect transistors (FETs) continue to decrease. However, the reduction in size of FETs comprising 3D semiconductors is limited by the rate at which heat, generated from static power, is dissipated. The increase in static power and the leakage of current between the source and drain electrodes that causes this increase, are referred to as short channel effects. In FETs with channels made from 2D semiconductors, leakage current is almost eliminated because all electrons are confined in atomically thin channels and, hence, are uniformly influenced by the gate voltage. In this Review, we provide a mathematical framework to evaluate the performance of FETs and describe the challenges for improving the performances of short channel FETs in relation to the properties of 2D materials, including graphene, transition metal dichalcogenides, phosphorene and silicene. We also describe tunnelling FETs that possess extremely low power switching behaviour and explain how they can be realized using heterostructures of 2D semiconductors. Field effect transistors (FETs) with semiconducting channels made from 2D materials are known to have fewer problems with short channel effects than devices comprising 3D semiconductors. In this Review, a mathematical framework to evaluate the performance of FETs is outlined with a focus on the properties of 2D materials, such as graphene, transition metal dichalcogenides, phosphorene and silicene.", "author_names": [ "Manish Chhowalla", "Debdeep Jena", "Hua Zhang" ], "corpus_id": 10265339, "doc_id": "10265339", "n_citations": 559, "n_key_citations": 6, "score": 1, "title": "Two dimensional semiconductors for transistors", "venue": "", "year": 2016 }, { "abstract": "As the dimensions of the semiconducting channels in field effect transistors decrease, the contact resistance of the metal semiconductor interface at the source and drain electrodes increases, dominating the performance of devices1 3. Two dimensional (2D) transition metal dichalcogenides such as molybdenum disulfide (MoS2) have been demonstrated to be excellent semiconductors for ultrathin field effect transistors4,5. However, unusually high contact resistance has been observed across the interface between the metal and the 2D transition metal dichalcogenide3,5 9. Recent studies have shown that van der Waals contacts formed by transferred graphene10,11 and metals12 on few layered transition metal dichalcogenides produce good contact properties. However, van der Waals contacts between a three dimensional metal and a monolayer 2D transition metal dichalcogenide have yet to be demonstrated. Here we report the realization of ultraclean van der Waals contacts between 10 nanometre thick indium metal capped with 100 nanometre thick gold electrodes and monolayer MoS2. Using scanning transmission electron microscopy imaging, we show that the indium and gold layers form a solid solution after annealing at 200 degrees Celsius and that the interface between the gold capped indium and the MoS2 is atomically sharp with no detectable chemical interaction between the metal and the 2D transition metal dichalcogenide, suggesting van der Waals type bonding between the gold capped indium and monolayer MoS2. The contact resistance of the indium/gold electrodes is 3,000 300 ohm micrometres for monolayer MoS2 and 800 200 ohm micrometres for few layered MoS2. These values are among the lowest observed for three dimensional metal electrodes evaporated onto MoS2, enabling high performance field effect transistors with a mobility of 167 20 square centimetres per volt per second. We also demonstrate a low contact resistance of 220 50 ohm micrometres on ultrathin niobium disulfide (NbS2) and near ideal band offsets, indicative of defect free interfaces, in tungsten disulfide (WS2) and tungsten diselenide (WSe2) contacted with indium alloy. Our work provides a simple method of making ultraclean van der Waals contacts using standard laboratory technology on monolayer 2D semiconductors.Ultraclean van der Waals bonds between gold capped indium and a monolayer of the two dimensional transition metal dichalcogenide molybdenum disulfide show desirably low contact resistance at the interface, enabling high performance field effect transistors.", "author_names": [ "Yan Alexander Wang", "Jong Chan Kim", "Ryan J Wu", "Jenny Martinez", "Xiuju Song", "Jieun Yang", "Fang Zhao", "Andre Mkhoyan", "Hu Young Jeong", "Manish Chhowalla" ], "corpus_id": 85527929, "doc_id": "85527929", "n_citations": 190, "n_key_citations": 0, "score": 0, "title": "Van der Waals contacts between three dimensional metals and two dimensional semiconductors", "venue": "Nature", "year": 2019 }, { "abstract": "Quinoidal oligothiophenes (QOT) as classical n type semiconductors, have been well known for a long time but with non optimal semiconducting properties. We report here the design and selective synthesis of new two dimensional (2D) p expanded quinoidal terthiophenes, 2DQTTs, with proximal (2DQTT i) and distal (2DQTT o) regiochemistry for high performance n channel organic thin film transistors (n OTFTs) featuring high electron mobility, solution processability, and ambient stability. The elegant combination of thieno[3,4 b]thiophene [TT, donor (D) and 5 alkyl 4H thieno[3,4 c]pyrrole 4,6(5H) dione [TPD, acceptor (A) units with relatively large p surface endows these 2DQTTs with distinctive 2D structural characteristics and flat configuration stabilized by weak intramolecular S O/S weak interactions. Furthermore, the A D A D A electronic structure maintains an adequately low LUMO energy level. These 2DQTTs are shown to exhibit outstanding semiconducting properties with electron mobilities of up to 3.0 cm(2) V( 1) s( 1) and on/off ratios of up to 10(6) (2DQTT o) in ambient and solution processed OTFTs. Investigations on thin film morphology reveal that the microstructure of 2DQTTs is highly dependent on the orientation of the fused thiophene subunits, leading to differences in electron mobilities of 1 order of magnitude. X ray diffraction studies in particular reveal increased crystallinity, crystalline coherence, and orientational order in 2DQTT o compared to 2DQTT i, which accounts for the superior electron transport property of 2DQTT o.", "author_names": [ "Cheng Zhang", "Yaping Zang", "Eliot Gann", "Christopher R McNeill", "Xiaozhang Zhu", "Chong-an Di", "Daoben Zhu" ], "corpus_id": 207116026, "doc_id": "207116026", "n_citations": 108, "n_key_citations": 0, "score": 0, "title": "Two dimensional p expanded quinoidal terthiophenes terminated with dicyanomethylenes as n type semiconductors for high performance organic thin film transistors.", "venue": "Journal of the American Chemical Society", "year": 2014 }, { "abstract": "Atomically thin transition metal dichalcogenides (TMDs) are of interest for next generation electronics and optoelectronics. Here, we demonstrate device ready synthetic tungsten diselenide (WSe2) via metal organic chemical vapor deposition and provide key insights into the phenomena that control the properties of large area, epitaxial TMDs. When epitaxy is achieved, the sapphire surface reconstructs, leading to strong 2D/3D (i.e. TMD/substrate) interactions that impact carrier transport. Furthermore, we demonstrate that substrate step edges are a major source of carrier doping and scattering. Even with 2D/3D coupling, transistors utilizing transfer free epitaxial WSe2/sapphire exhibit ambipolar behavior with excellent on/off ratios ~107) high current density (1 10 mA*mm 1) and good field effect transistor mobility ~30 cm2*V 1*s 1) at room temperature. This work establishes that realization of electronic grade epitaxial TMDs must consider the impact of the TMD precursors, substrate, and the 2D/3D interface as leading factors in electronic performance.", "author_names": [ "Yu-Chuan Lin", "B Jariwala", "Brian M Bersch", "Ke Xu", "Yifan Nie", "Baoming Wang", "Sarah M Eichfeld", "Xiaotian Zhang", "Tanushree H Choudhury", "Yi Pan", "Rafik Addou", "Christopher M Smyth", "Jun Li", "Kehao Zhang", "M Aman Haque", "Stefan Folsch", "Randall M Feenstra", "Robert M Wallace", "Kyeongjae Cho", "Susan K Fullerton-Shirey", "Joan M Redwing", "Joshua A Robinson" ], "corpus_id": 3658613, "doc_id": "3658613", "n_citations": 102, "n_key_citations": 2, "score": 0, "title": "Realizing Large Scale, Electronic Grade Two Dimensional Semiconductors.", "venue": "ACS nano", "year": 2018 }, { "abstract": "Atomically thin two dimensional semiconductors feature silicon like band gaps and native high k metal oxides. The success of silicon as a dominant semiconductor technology has been enabled by its moderate band gap (1.1 eV) permitting low voltage operation at reduced leakage current, and the existence of SiO2 as a high quality \"native\" insulator. In contrast, other mainstream semiconductors lack stable oxides and must rely on deposited insulators, presenting numerous compatibility challenges. We demonstrate that layered two dimensional (2D) semiconductors HfSe2 and ZrSe2 have band gaps of 0.9 to 1.2 eV (bulk to monolayer) and technologically desirable \"high k\" native dielectrics HfO2 and ZrO2, respectively. We use spectroscopic and computational studies to elucidate their electronic band structure and then fabricate air stable transistors down to three layer thickness with careful processing and dielectric encapsulation. Electronic measurements reveal promising performance (on/off ratio 106; on current, ~30 mA/mm) with native oxides reducing the effects of interfacial traps. These are the first 2D materials to demonstrate technologically relevant properties of silicon, in addition to unique compatibility with high k dielectrics, and scaling benefits from their atomically thin nature.", "author_names": [ "Michal J Mleczko", "Chaofan Zhang", "Hye Ryoung Lee", "Hsueh-Hui Kuo", "Blanka Magyari-Kope", "Robert G Moore", "Zhi-Xun Shen", "Ian R Fisher", "Yoshio Nishi", "Eric Pop" ], "corpus_id": 1061372, "doc_id": "1061372", "n_citations": 98, "n_key_citations": 0, "score": 0, "title": "HfSe2 and ZrSe2: Two dimensional semiconductors with native high k oxides", "venue": "Science Advances", "year": 2017 }, { "abstract": "Two dimensional semiconductors could be used to fabricate ultimately scaled field effect transistors and more than Moore nanoelectronic devices. However, these targets cannot be reached without appropriate gate insulators that are scalable to the nanometre range. Typically used oxides such as SiO2, Al2O3 and HfO2 are, however, amorphous when scaled, and 2D hexagonal boron nitride exhibits excessive gate leakage currents. Here, we show that epitaxial calcium fluoride (CaF2) which can form a quasi van der Waals interface with 2D semiconductors, can serve as an ultrathin gate insulator for 2D devices. We fabricate scalable bilayer MoS2 field effect transistors with a crystalline CaF2 insulator of ~2 nm thickness, which corresponds to an equivalent oxide thickness of less than 1 nm. Our devices exhibit low leakage currents and competitive device performance characteristics, including subthreshold swings down to 90 mV dec 1, on/off current ratios up to 107 and a small hysteresis.High performance MoS2 transistors can be created using 2 nm thick CaF2 as a gate insulator, which forms a quasi van der Waals interface with the 2D semiconductor.", "author_names": [ "Yu Yu Illarionov", "Alexander G Banshchikov", "Dmitry K Polyushkin", "Stefan Wachter", "Theresia Knobloch", "Mischa Thesberg", "Lukas Mennel", "Matthias Paur", "Michael Stoger-Pollach", "Andreas Steiger-Thirsfeld", "Mikhail I Vexler", "Michael Waltl", "Nikolai S Sokolov", "T Mueller", "Tibor Grasser" ], "corpus_id": 189929639, "doc_id": "189929639", "n_citations": 48, "n_key_citations": 0, "score": 0, "title": "Ultrathin calcium fluoride insulators for two dimensional field effect transistors", "venue": "Nature Electronics", "year": 2019 }, { "abstract": "Two dimensional semiconductors have a number of valuable properties that could be used to create novel electronic devices. However, creating 2D devices with good contacts and stable performance has proved challenging. Here we show that transferred via contacts, made from metal embedded in insulating hexagonal boron nitride and dry transferred onto 2D semiconductors, can be used to create high quality 2D transistors. The approach prevents damage induced by direct metallization and allows full glovebox processing, providing a clean, stable and damage free platform for 2D device fabrication. Using the approach, we create field effect transistors (FETs) from bilayer p type tungsten diselenide (WSe2) that exhibit high hole mobility and low contact resistance. The fabricated devices also exhibit high current and stability for over two months of measurements. Furthermore, the low contact resistance and clean channel allow us to create a nearly ideal top gated p FET with a subthreshold swing of 64 mV per decade at 290 K.Bilayer WSe2 field effect transistors with near ideal device characteristics can be created using transferred via contacts made from metal embedded hexagonal boron nitride.", "author_names": [ "Younghun Jung", "Min Sup Choi", "Ankur Nipane", "Abhinandan Borah", "Bumho Kim", "Amirali Zangiabadi", "Takashi Taniguchi", "Kenji Watanabe", "Won Jong Yoo", "James C Hone", "James T Teherani" ], "corpus_id": 182892564, "doc_id": "182892564", "n_citations": 49, "n_key_citations": 0, "score": 0, "title": "Transferred via contacts as a platform for ideal two dimensional transistors", "venue": "Nature Electronics", "year": 2019 }, { "abstract": "Two dimensional (2D) layered materials hold great promise for various future electronic and optoelectronic devices that traditional semiconductors cannot afford. 2D pnictogen, group VA atomic sheet (including phosphorene, arsenene, antimonene, and bismuthene) is believed to be a competitive candidate for next generation logic devices. This is due to their intriguing physical and chemical properties, such as tunable midrange bandgap and controllable stability. Since the first black phosphorus field effect transistor (FET) demo in 2014, there has been abundant exciting research advancement on the fundamental properties, preparation methods, and related electronic applications of 2D pnictogen. Herein, we review the recent progress in both material and device aspects of 2D pnictogen FETs. This includes a brief survey on the crystal structure, electronic properties and synthesis, or growth experiments. With more device orientation, this review emphasizes experimental fabrication, performance enhancing approaches, and configuration engineering of 2D pnictogen FETs. At the end, this review outlines current challenges and prospects for 2D pnictogen FETs as a potential platform for novel nanoelectronics.", "author_names": [ "Wenhan Zhou", "Jiayi Chen", "Pengxiang Bai", "Shiying Guo", "Shengli Zhang", "Xiufeng Song", "Lijuan Tao", "Haibo Zeng" ], "corpus_id": 208162944, "doc_id": "208162944", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Two Dimensional Pnictogen for Field Effect Transistors", "venue": "Research", "year": 2019 }, { "abstract": "Layered two dimensional semiconductors have attracted tremendous attention owing to their demonstrated excellent transistor switching characteristics with a large ratio of on state to off state current, Ion/Ioff. However, the depletion mode nature of the transistors sets a limit on the thickness of the layered semiconductor films primarily determined by a given Ion/Ioff as an acceptable specification. Identifying the optimum thickness range is of significance for material synthesis and device fabrication. Here, we systematically investigate the thickness dependent switching behavior of transistors with a wide thickness range of multilayer MoS2 films. A difference in Ion/Ioff by several orders of magnitude is observed when the film thickness, t, approaches a critical depletion width. The decrease in Ion/Ioff is exponential for t between 20 nm and 100 nm, by a factor of 10 for each additional 10 nm. For t larger than 100 nm, Ion/Ioff approaches unity. Simulation using technical computer aided tools established for silicon technology faithfully reproduces the experimentally determined scaling behavior of Ion/Ioff with t. This excellent agreement confirms that multilayer MoS2 films can be approximated as a homogeneous semiconductor with high surface conductivity that tends to deteriorate Ion/Ioff. Our findings are helpful in guiding material synthesis and designing advanced field effect transistors based on the layered semiconductors.", "author_names": [ "Youwei Zhang", "Hui Li", "Haomin Wang", "H Xie", "Ran Liu", "Shi-Li Zhang", "Zhi-Jun Qiu" ], "corpus_id": 1261049, "doc_id": "1261049", "n_citations": 32, "n_key_citations": 1, "score": 0, "title": "Thickness Considerations of Two Dimensional Layered Semiconductors for Transistor Applications", "venue": "Scientific reports", "year": 2016 }, { "abstract": "Two dimensional semiconductors (2DSCs) have attracted considerable attention as atomically thin channel materials for field effect transistors. Each layer in 2DSCs consists of a single or few atom thick, covalently bonded lattice, in which all carriers are confined in their atomically thin channel with superior gate controllability and greatly suppressed OFF state current, in contrast to typical bulk semiconductors plagued by short channel effects and heat generation from static power. Additionally, 2DSCs are free of surface dangling bonds that plague traditional semiconductors, and hence exhibit excellent electronic properties at the limit of single atom thickness. Therefore, 2DSCs can offer significant potential for the ultimate transistor scaling to single atomic body thickness. Earlier studies of graphene transistors have been limited by the zero bandgap and low ON OFF ratio of graphene, and transition metal dichalcogenide (TMDC) devices are typically plagued by insufficient carrier mobility. To this end, considerable efforts have been devoted towards searching for new 2DSCs with optimum electronic properties. Within a relatively short period of time, a large number of 2DSCs have been demonstrated to exhibit unprecedented characteristics or unique functionalities. Here we review the recent efforts and progress in exploring novel 2DSCs beyond graphene and TMDCs for ultra thin body transistors, discussing the merits, limits and prospects of each material.", "author_names": [ "Yuan Liu", "Xidong Duan", "Yu Huang", "Xiangfeng Duan" ], "corpus_id": 51921760, "doc_id": "51921760", "n_citations": 135, "n_key_citations": 0, "score": 0, "title": "Two dimensional transistors beyond graphene and TMDCs.", "venue": "Chemical Society reviews", "year": 2018 } ]

[ { "abstract": "For plasma etching process, developing efficient real time fault detection systems is an active research area of semiconductor manufacturing, especially the systems using Optical Emission Spectroscopy(OES) data. Besides, as a typical multiphase process, it is promising to apply multiphase methods in the OES fault detection system. However, the process drifts existing in the system will lead to severe drifts in time direction and cause model mismatch issue when applying the multiphase methods. To cope with these problems, a real time fault detection system for multiphase plasma etching using OES, two step division and change stage alignment method is proposed in this paper. By capturing changes in process, a two step division method divides the process into stationary phases and transition phases. To better overcome the drift problem, change stage in transition phase is further aligned before MPCA modeling and online monitoring. Case studies have shown that the proposed system is more reliable and sensitive comparing to the reference model and can better overcome the model mismatch problem.", "author_names": [ "Jiayang Ren", "Dong Ni" ], "corpus_id": 211206467, "doc_id": "211206467", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Real time Fault Detection System for Multiphase Plasma Etching Process using OES, Two Step Division and Change Stage Alignment Method", "venue": "2019 Chinese Automation Congress (CAC)", "year": 2019 }, { "abstract": "As the technology node shrinks and shifts towards complex architectures, accurate control of automated semiconductor manufacturing processes, particularly plasma etching, is crucial in yield, cost, and semiconductor performance. However, current endpoint detection (EPD) methods relying on the experience of skilled engineers result in process variations and even errors. This paper proposes an enhanced optimal EPD in the plasma etching process based on a convolutional neural network (CNN) The proposed approach performs feature extraction on the spectral data obtained by optical emission spectroscopy (OES) and successfully predicts optimal EPD time. For the purpose of comparison, the support vector machine (SVM) classifier and the Adaboost Ensemble classifier are also investigated; the CNN based model demonstrates better performance than the two models.", "author_names": [ "Bobae Kim", "Sungbin Im", "Geonwook Yoo" ], "corpus_id": 234435334, "doc_id": "234435334", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Performance Evaluation of CNN Based End Point Detection Using In Situ Plasma Etching Data", "venue": "", "year": 2020 }, { "abstract": "In this study, the Gaussian mixture model (GMM) was modified and implemented to determine the real time endpoint of SiO2 plasma etching using optical emission spectrum analysis. Optical emission spectroscopy (OES) signals were collected from the SiO2 plasma etching processes, and the modified GMM was applied to SiO2 etching with relative areas of 8.0, 4.0, and 1.0 Consequently, the sensitivity of OES signals was improved by ~5.5 times, and the sensitivity factor of the modified GMM was increased by approximately two times, compared with those of the modified K means cluster analysis (another clustering technique) In addition, 60 peaks related to the reactants were selected out of 6144 signals to improve the sensitivity of the modified GMM with full spectrum wavelengths. The modified GMM analysis using the 60 reactant related peaks exhibited a higher sensitivity ~1.4 times) than that with 6144 full spectrum OES signals. Thus, the modified GMM can be a suitable and effective clustering technique for etching endpoint detection.", "author_names": [ "Sangin Lee", "Haegyu Jang", "Yongjae Kim", "Sun Jung Kim", "Heeyeop Chae" ], "corpus_id": 214450188, "doc_id": "214450188", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Sensitivity Enhancement of SiO2 Plasma Etching Endpoint Detection Using Modified Gaussian Mixture Model", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2020 }, { "abstract": "The semiconductor industry has played a crucial role in societal development over the past several decades. Plasma etching is a key processing step employed in Integrated Circuit (IC) fabrication. In order to improve product yield, Optical Emission Spectroscopy (OES) is widely used to monitor the etching process. OES generates high dimensional data, which has a large information capacity but also has significant information redundancy. Based on plasma OES characteristics, two novel data analysis methods are proposed in this thesis: the Internal Information Redundancy Reduction (IIRR) method for dimension and redundancy reduction and Similarity Ratio Analysis (SRA) for fault detection. By identifying peak wavelength emissions and the correlative relationships between them, IIRR outputs a subset of the original variables. Data dimensionality is reduced significantly by IIRR with minimal information loss. The SRA method is intended for early stage faultdetection in plasma etching processes using real time OES data as input. The SRA method can help to realise a highly precise control system by detecting abnormal etch rate faults in real time during an etching process, so less energy and materials will be wasted by faulty processing. Generally, previous research on OES measurements of plasma etching has largely focused on particular target applications and has used methods that rely on transforming the original data into an abstract variable space. In contrast, our approach operates directly in the original variable space allowing a more direct and easier interpretation of the dimension reduced data.", "author_names": [ "Jie Yang" ], "corpus_id": 203944515, "doc_id": "203944515", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Multivariable OES data analysis for semiconductor plasma etching process", "venue": "", "year": 2014 }, { "abstract": "Abstract This work presents a redeposition free process to etch silicon by CF4 plasma in a modified microwave oven reactor operated in a medium vacuum process regime (25 to 1 x 10 3 Torr) that only uses a mechanical pump which is introduced at a lower cost compared to the ICP etching system. In order to achieve the capability of the etching process provided by this system, experimental trials were conducted by varying the microwave power in the range of 360 1200 W, gas flow rate 30 90 mL/min and bias voltage at the substrate holder 100 V to 300 V. Plasma species present in the discharge were also monitored by optical emission spectroscopy (OES) for a better understanding of the mechanism of the etching process. The etched sidewalls were observed by scanning electron microscope (SEM) the etched roughness was measured by atomic force microscope (AFM) and the etched depths were measured by a stylus profiling technique.", "author_names": [ "Chupong Pakpum", "Dheerawan Boonyawan" ], "corpus_id": 219909979, "doc_id": "219909979", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Redeposition free of silicon etching by CF4 microwave plasma in a medium vacuum process regime", "venue": "", "year": 2020 }, { "abstract": "Fault detection was carried out in a etcher of capacitive coupled plasma with OES (Optical Emission Spectroscopy) and impedance by VI probe that are widely used for process control and monitoring at semiconductor industry. The experiment was operated at conventional Ar and Fluorocarbon plasma with variable change such as pressure and addition of N2 and O2 to assume atmospheric leak, RF power and pressure that are highly possible to impact wafer yield during wafer process, in order to observe OES and VI Probe signals. The sensitivity change on OES and Impedance by VI probe was analyzed by statistical method including PCA to determine healthy of process. The main goal of this study is to find feasibility and limitation of OES and Impedances for fault detection by shift of plasma characteristics and to enhance capability of fault detection using PCA.", "author_names": [ "Sanghyuk Choi", "Haegyu Jang", "Heeyeop Chae" ], "corpus_id": 112814933, "doc_id": "112814933", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Fault Detection of Plasma Etching Processes with OES and Impedance at CCP Etcher", "venue": "", "year": 2012 }, { "abstract": "Optical Emission Spectra (OES) is a widely used signal in plasm etching. In this paper, an OES structural feature based fault detection method is proposed. Firstly, a template of normal OES curves is extracted via non negative matrix factorization. Then singular points of the curves are detected by local matching based on the template. The magnitude and occurrence time of these singular points form a structural feature vector, which is a quantitative and simplified description of the curve's shape. Lastly, one class SVM is introduced for generate a fault detection model based on structural feature vectors from normal OES curves. Experiments on an industrial benchmark dataset show that the proposed method is effective.", "author_names": [ "Lihui Zhao", "Huangang Wang", "Wenli Xu" ], "corpus_id": 16101433, "doc_id": "16101433", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "OES structural feature based fault detection method for plasma etching", "venue": "2012 International Conference on Systems and Informatics (ICSAI2012)", "year": 2012 }, { "abstract": "Abstract Surface texturing of a carbon based thin film is the critical technology in the development of functional surface for many kinds of sensors. This study explored the possibilities of processing the carbon film's surface by means of plasma etching to produce micro pillars. Circular dots with a diameter of 25 mm, 50 mm, and 100 mm were printed on a thick carbon film. A high density oxygen plasma was generated by a combination of RF and DC power in a vacuum chamber. The high density plasma was applied onto the surface of a diamond like carbon film. The printed pattern serves as a mask like in the lithography technique. The oxidation reaction was expected on the exposed surface, i.e. the area surrounded the dots. The results show the oxidation effectively removed the carbon on the unmasked area producing 3D circular patterns. The plasma processing, which was carried out for 2 h, was monitored and diagnosed using optical emission spectroscopy (OES) The oxidation was controlled by atomic oxygen which was the dominant species observed in the plasma. The removal (etching) rate was 9 mm/h with 91% 98% and 99% pattern accuracy related to the larger diameter studied in this work. Observations using a Raman spectroscopy confirmed that the printed mask effectively protects the DLC from the etching process and other indirect processes.", "author_names": [ "J D H Dionysius Santjojo", "W Sukma Fitriani", "", "P Setyawan Sakti" ], "corpus_id": 234178399, "doc_id": "234178399", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Fabrication of Micro Pillar by plasma etching texturing of Carbon Based thin film", "venue": "", "year": 2021 }, { "abstract": "In this study, we evaluate the defects and charges caused by the ultraviolet (UV)/vacuum ultraviolet (VUV) irradiation in the high k/metal gate stack structure, especially in HfO2 layer and at Si/HfO2 interface. First, we measured the photons irradiating to the surface in the neutral beam etching (NBE) system and in the conventional inductively coupled plasma (ICP) system through optical emission spectroscopy (OES) respectively. By using this method, we evaluate the ability of reducing UV/VUV irradiation damage in the NBE system. As a result, photon intensity detected in the ICP system shows larger magnitude as compared to the NBE system, which indicates the UV/VUV irradiation is more severe in the ICP system. Moreover, in order to understand the twisting of electrical characteristics caused by UV/VUV irradiation, we set the prefabricated metal oxide semiconductor (MOS) capacitors in both systems to absorb the irradiation of UV/VUV photons respectively. The electrical characteristics of the etched MOS capacitors and its related plasma induced damage model are discussed. The result of the devices exposed in the ICP system reveals a greater electrical characteristics shift compared to the devices in NBE such as the interface trap density (Dit) in case of NBE is 3.55621x1012 cm 2eV 1 and in case of ICP is higher i.e. 4.19961x1012 cm 2eV 1.", "author_names": [ "Si-Qi Zeng", "K C Chuang", "Ashish Kumar", "Wen-Hsi Lee" ], "corpus_id": 231770852, "doc_id": "231770852", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Influence of Plasma Ultraviolet/Vacuum Ultraviolet Irradiation Damage on Silicon Metal Oxide Semiconductor Capacitor During Etching.", "venue": "Journal of nanoscience and nanotechnology", "year": 2021 }, { "abstract": "Abstract Theendpointdetection(EPD)isthemostimportanttechniqueinplasmaetchingprocess.Inplasmaetchingprocess,theOpticalEmissionSpectroscopy(OES)isusuallyusedtoanalyzeplasmareaction.AndPlasmaImpedanceMonitoring(PIM)systemisusedtomeasurethevoltage,current,power,andloadimpedanceofthesuppliedRFpowerduringplasmaprocess.Inthispaper,anewdecisionmakingalgorithmisproposedtoimprovetheperformanceofEPDinSiOxsinglelayerplasmaetching.Toenhancetheaccuracyoftheendpointdetection,bothOESdataandPIMdataareutilizedandanewlyproposeddecisionmakingalgorithmisapplied.Theproposedmethodsuccessfullydetectedendpointofsiliconoxideplasmaetching. yo yag peulrajeumasiggaggongjeongeseosiggagjongryojeomgeomculeunjungyohanyosoida.OpticalEmissionSpectroscopy(OES)neunpeulrajeumabaneungeulbunseoghaneundesayonghanda.geurigoPlasmaImpedanceMonitoring(PIM)eunpeulrajeumagongjeongjungeRFpowereyihanvoltage,current,power,impedancereulbunseoghaneundesayonghanda.bonnonmuneseoneunsaerojeanhaneunyisagyeoljeongalgorijeumeuliyonghayeosinglelayersanhwamagpeulrajeumasiggageseosiggagjongryojeomgeomculyiseongneungeulhyangsangsikineungeoseuljeanhanda.siggagjongryojeomgeomculyijeonghwagdoreulnopigiwihaeOESdeiteowaPIMdeiteodeuleulyisagyeoljeongalgorijeumemodujeogyonghayeosayonghanda.jeandoenbangbeobeunSiOxpeulrajeumasiggageseosiggagjongryojeomeuljeonghwaghagegeomculhanda.Keywords:EndpointDetection(EPD),DecisionMakingAlgorithm,OpticalEmissionSpectroscopy(OES),PlasmaImpedanceMonitoring(PIM),HiddenMarkovModel(HMM)ISSN: 1226 7244 (Print)ISSN: 2288 243X (Online)nonmunbeonho 16 01 02", "author_names": [ "Ho-Taek Noh", "Young-Kook Park", "Seung-Soo Han" ], "corpus_id": 112144840, "doc_id": "112144840", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Real Time Endpoint Detection in Plasma Etching Using Decision Making Algorithm", "venue": "", "year": 2016 } ]

[ { "abstract": "Steadily decreasing prices and improved performance of semiconductor devices have raised expectations towards the development and large scale application of motor mounted static converters. In view of this, the design of a rectifier inverter type of frequency changer which requires very small reactive components is considered. Accordingly, rectifier and inverter PWM schemes which generate the minimum possible harmonic distortion are first discussed. By using a suitable analysis method, `optimum' design data are obtained for every major system component. Resulting reactive component values are shown to be considerably smaller than the ones required by typical rectifier inverter structures. Predicted key results are verified by computer simulation.", "author_names": [ "Phoivas D Ziogas", "Young-Goo Kang", "Victor R Stefanovic" ], "corpus_id": 16435560, "doc_id": "16435560", "n_citations": 25, "n_key_citations": 0, "score": 0, "title": "Optimum System Design of a Three Phase Rectifier Inverter Type of Frequency Changer", "venue": "IEEE Transactions on Industry Applications", "year": 1985 }, { "abstract": "A new three phase rectifier/converter with low harmonic input currents and minimal DC voltage ripple is described. The device achieves continuous input line currents by injecting a triangular third harmonic current, derived from the DC link current, into the neutral point of a delta star transformer at the supply. It uses a conventional six pulse phase controlled converter, with an additional bridge of four devices in the DC link. The additional bridge also cancels much of the DC voltage ripple, allowing a much smaller DC link inductance to be used. A prototype 10 kW system, suitable for such applications as DC motor drives, load commutated inverters, exciters for AC generators, and low power DC links is described. Experimental results obtained from this system are compared with ideal theoretical predictions.", "author_names": [ "John T Boys", "Brian Mitchell" ], "corpus_id": 110911102, "doc_id": "110911102", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Current forced neutral injection in a three phase rectifier/converter", "venue": "", "year": 1999 }, { "abstract": "PURPOSE: To suppress fluctuation in the rotating force and torque of a motor by regulating the magnitude of a Hall effect rectification signal thereby controlling the square sum of constant of all polyphase rectification signals. CONSTITUTION: A field sensor 14 generates an output voltage proportional to the field strength and a current being fed to a sensor and connected with a square sum correction means 16 and a polyphase motor coil 12. The square sum correction means 16 receives rectification signals from the field sensor 14 and generates the square sum thereof. Subsequently, the square sum correction means 16 generates a correction signal which is delivered to the field sensor 14. Purpose of the correction signal is to sustain the square sum of signals from the field sensor 14 constantly at a predetermined value. The correct signal from the field sensor 14 is modulated by a motor control signal 18 in order to drive a motor. Fluctuation in the rotating force and torque of the motor is suppressed significantly by a corrected rectification signal from the field sensor 14. COPYRIGHT: (C)1994,JPO", "author_names": [ "Daniel N Galburt", "garubato danieru" ], "corpus_id": 125147132, "doc_id": "125147132", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Electric motor having reduced fluctuation of rotating force, three phase electric motor with sinusoidal rectifier, control method for three phase brushless electric motor having sinusoidal rectification signal, and control method for three phase brushless electric motor", "venue": "", "year": 1993 }, { "abstract": "", "author_names": [ "M Sakui", "Akio Yanase", "Hiroshi Fujita" ], "corpus_id": 110970057, "doc_id": "110970057", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A method for calculating the characteristics of secondary excited induction motor with a three phase bridge rectifier in the rotor circuit", "venue": "", "year": 1988 }, { "abstract": "", "author_names": [ "Masaaki Sakui", "Akio Yanase", "Hiroshi Fujita", "Mitsuo Shioya" ], "corpus_id": 111927297, "doc_id": "111927297", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Method for Calculating Characteristics of Secondary Excited Induction Motor with a Three Phase Bridge Rectifier in the Rotor Circuit", "venue": "", "year": 1988 }, { "abstract": "", "author_names": [ "William Shepherd", "L N Hulley", "Darwin T W Liang" ], "corpus_id": 108534091, "doc_id": "108534091", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Power electronics and motor control: Three phase naturally commutated bridge circuit as a rectifier or inverter", "venue": "", "year": 1996 }, { "abstract": "The advent of the silicon controlled rectifier has permitted the design of a practical cycloconverter source of 3 phase electrical power which can be continuously controlled in frequency, from dc to approximately one half the input power frequency, as required to control the speed of a 3 phase induction motor. The correspondence between the applied stator frequency, the resulting magnetic flux phase rotation, and the mechanical rotor rotation in a 3 phase induction motor is analyzed as a function of slip. A closed loop feedback system is described for controlling the slip between the rotor and rotating magnetic flux and for optimizing the slip frequency over the full reversible speed range of the motor. The stepless control of angular position, velocity and acceleration, and torque in both the driving and braking modes of operation is discussed.", "author_names": [ "Walter Slabiak", "Louis J Lawson" ], "corpus_id": 109794289, "doc_id": "109794289", "n_citations": 31, "n_key_citations": 2, "score": 0, "title": "Precise Control of a Three Phase Squirrel Cage Induction Motor Using a Practical Cycloconverter", "venue": "", "year": 1966 }, { "abstract": "A single phase to three phase converter for a low cost AC motor drive is proposed. The converter employs only six switches and incorporates a front end half bridge active rectifier structure that provides the DC link with an active input current shaping feature, which results in sinusoidal input current at close to unity power factor. The front end rectifier in the converter permits bidirectional power flow and provides for excellent regulation against fluctuations in source voltage, facilitating regenerative braking of the AC motor drive. A control strategy that maintains a near unity power factor over the full operating range and is easy to implement is described. Suitable design guides for the selection of filter components are presented. Simulation and experimental results that verify the developed theoretical models are also presented.<ETX>", "author_names": [ "Prasad N Enjeti", "Ashek Rahman" ], "corpus_id": 17631874, "doc_id": "17631874", "n_citations": 275, "n_key_citations": 8, "score": 1, "title": "A new single phase to three phase converter with active input current shaping for low cost AC motor drives", "venue": "Conference Record of the 1990 IEEE Industry Applications Society Annual Meeting", "year": 1990 }, { "abstract": "Modeling and control of a three phase PWM boost rectifier is presented. A current controller in rotating coordinates assures unity input power factor and fast output voltage regulation. Sensitivity of stability margins to different loads is analyzed. Two typical loads, a DC DC power converter and an inverter supplying an AC motor, are considered. Linear and nonlinear current controllers in the direct axis are compared. With the nonlinear controller, which employs load current feedforward, the rectifier sensitivity to load variations is greatly reduced and a single optimal output voltage compensator can be designed for all load conditions. Small signal output impedance is significantly improved, and faster transient response is obtained. The results are illustrated with simulations of a practical 10 kW rectifier.<ETX>", "author_names": [ "Silva Hiti", "Dushan Boroyevich" ], "corpus_id": 108876177, "doc_id": "108876177", "n_citations": 67, "n_key_citations": 4, "score": 0, "title": "Control of front end three phase boost rectifier", "venue": "Proceedings of 1994 IEEE Applied Power Electronics Conference and Exposition ASPEC'94", "year": 1994 }, { "abstract": "A low cost four quadrant single phase to three phase converter for AC drives is described. The technique uses a single phase reversible rectifier operating at unity power factor to produce a balanced DC supply at a controlled high voltage using two IGBT power transistors. Four additional IGBT power switches operate on this high voltage to produce two pulse width modulated (PWM) waveforms using a novel space vector modulation (SVM) strategy. A three phase motor load is then connected to the centre of the DC supply, and the two PWM voltages, to give a four quadrant reversing AC drive. The unique feature of this system is the modulation strategy, which achieves higher motor voltages than any previous published method while achieving excellent harmonic suppression at high efficiency in motor sizes restricted to the rating of the single phase supply (typically 2 kW)<ETX>", "author_names": [ "Grant Anthony Covic", "G L Peters", "John T Boys" ], "corpus_id": 109889071, "doc_id": "109889071", "n_citations": 66, "n_key_citations": 3, "score": 0, "title": "An improved single phase to three phase converter for low cost AC motor drives", "venue": "Proceedings of 1995 International Conference on Power Electronics and Drive Systems. PEDS 95", "year": 1995 } ]

[ { "abstract": "High frequency link (HFL) power conversion systems (PCSs) are attracting more and more attentions in academia and industry for high power density, reduced weight, and low noise without compromising efficiency, cost, and reliability. In HFL PCSs, dual active bridge (DAB) isolated bidirectional dc dc converter (IBDC) serves as the core circuit. This paper gives an overview of DAB IBDC for HFL PCSs. First, the research necessity and development history are introduced. Second, the research subjects about basic characterization, control strategy, soft switching solution and variant, as well as hardware design and optimization are reviewed and analyzed. On this basis, several typical application schemes of DAB IBDC for HPL PCSs are presented in a worldwide scope. Finally, design recommendations and future trends are presented. As the core circuit of HFL PCSs, DAB IBDC has wide prospects. The large scale practical application of DAB IBDC for HFL PCSs is expected with the recent advances in solid state semiconductors, magnetic and capacitive materials, and microelectronic technologies.", "author_names": [ "Biao Zhao", "Qiang Song", "Wenhua Liu", "Yandong Sun" ], "corpus_id": 39713522, "doc_id": "39713522", "n_citations": 794, "n_key_citations": 48, "score": 1, "title": "Overview of Dual Active Bridge Isolated Bidirectional DC DC Converter for High Frequency Link Power Conversion System", "venue": "IEEE Transactions on Power Electronics", "year": 2014 }, { "abstract": "Renewable energy generations have been attracting sustained attentions in academic and industry. Current fed isolated bidirectional dc/dc converters (CF IBDCs) are widely adopted in low voltage high current applications such as solar photovoltaic fuel cell with energy storage. This paper gives an overview and a comprehensive comparative evaluation of CF IBDCs. The active clamped, dual half bridge, L L type dual active bridge, resonant type, naturally clamped, and other type topologies of CF IBDCs are investigated, analyzed, and compared regarding their circuit topological structures, operation characteristics, modulation methods, and soft switching technologies. In addition, component cost models and loss models of converters are deduced and presented. On this basis, quantitative and comprehensive performance comparison of seven typical CF IBDC topologies selected from each type is conducted in terms of costs, losses, weight, volume, and power density for the given system specifications and design constraints. Finally, the application range of different CF IBDCs and future trend are presented to encourage further development.", "author_names": [ "Xuewei Pan", "Hongqi Li", "Yitao Liu", "Tianyang Zhao", "Chenchen Ju", "Akshay Kumar Rathore" ], "corpus_id": 201243786, "doc_id": "201243786", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "An Overview and Comprehensive Comparative Evaluation of Current Fed Isolated Bidirectional DC/DC Converter", "venue": "IEEE Transactions on Power Electronics", "year": 2020 }, { "abstract": "A novel bidirectional dc dc converter based on the quasi Z source (qZS) topology is presented in this paper. During battery discharge, it operates as the conventional qZS full bridge converter with a synchronous voltage doubler rectifier. During battery charging, it operates as the half bridge converter with a synchronous full bridge rectifier and LC filter. A relay is used for reconfiguration between those two modes. The operation principle is explained, and design guidelines are provided. A prototype with a nominal power of 300 W is used for verification of steady state regulation characteristics and efficiency measurements in the input voltage range compatible with an eight cell LiFePO4 battery. Closed loop control system for the converter application in dc microgrids is presented and tested in two control scenarios: dc bus signaling and direct reference defined by a master controller through a communication channel.", "author_names": [ "Andrii Chub", "Dmitri Vinnikov", "Roman Kosenko", "Elizaveta Liivik", "Ilya Galkin" ], "corpus_id": 115518223, "doc_id": "115518223", "n_citations": 24, "n_key_citations": 0, "score": 0, "title": "Bidirectional DC DC Converter for Modular Residential Battery Energy Storage Systems", "venue": "IEEE Transactions on Industrial Electronics", "year": 2020 }, { "abstract": "The triple phase shift (TPS) modulation scheme, which provides three control freedoms, is of great importance for the optimized operation of a dual active bridge (DAB) isolated bidirectional dc/dc converter. First of all, this paper introduces an accurate, universal model to describe the analytic expressions of the DAB converter under TPS control. Based on this, six operating modes of the DAB converter are further discussed. Afterwards, the concept of global optimal condition (GOC) equations is proposed to derive the closed form of analytic expressions of an optimal modulation scheme that makes the DAB converter operate with minimized root mean square (rms) current during whole power range with different operating modes. According to the GOC equations, the physical explanation of the proposed modulation scheme is further given in details, and the complex interaction among the control variables, the transferred power, and rms current is revealed. The real time optimization process of the proposed method is also specified. Finally, the proposed methods are applied to a laboratory prototype. The experimental results confirm the theoretical analysis and practical feasibility of the proposed strategies.", "author_names": [ "Anping Tong", "Lijun Hang", "Guojie Li", "Xiuchen Jiang", "Shenyu Gao" ], "corpus_id": 3410362, "doc_id": "3410362", "n_citations": 108, "n_key_citations": 14, "score": 0, "title": "Modeling and Analysis of a Dual Active Bridge Isolated Bidirectional DC/DC Converter to Minimize RMS Current With Whole Operating Range", "venue": "IEEE Transactions on Power Electronics", "year": 2018 }, { "abstract": "This paper presents a comprehensive analysis of the current stress optimization and soft switching operation of the isolated bidirectional dual active bridge (DAB) dc dc converter with the unified triple phase shift (UTPS) control. On this basis, the current stress optimized modulation scheme is proposed for DAB, which leads to the minimum current stress with the required transmission power and voltage conversion ratio in the whole load range. Moreover, the full soft switching operation is achieved for the converter simultaneously. Distinct from the previous modulation schemes, the proposed optimized modulation scheme is deduced from a unified analysis of TPS where all effective switching modes are investigated. A novel algorithm based on the Karush Kuhn Tucker (KKT) conditions is originally proposed to derive closed form solutions for the global optimal control parameters. This paper also presents a typical closed loop control strategy for DAB with TPS control and detailed descriptions about the closed loop operation. A laboratory prototype is applied, and the experimental results validate that the current stress optimization and efficiency improvement are realized by applying the optimized modulation scheme. The experimental results also verify the effectiveness of the closed loop control strategy for DAB with TPS control.", "author_names": [ "Jun Huang", "Yue Wang", "Zhuoqiang Li", "Wanjun Lei" ], "corpus_id": 40598350, "doc_id": "40598350", "n_citations": 155, "n_key_citations": 13, "score": 0, "title": "Unified Triple Phase Shift Control to Minimize Current Stress and Achieve Full Soft Switching of Isolated Bidirectional DC DC Converter", "venue": "IEEE Transactions on Industrial Electronics", "year": 2016 }, { "abstract": "In this paper, a hybrid switched capacitor/switched quasi Z source bidirectional dc dc converter is proposed for electric vehicles (EVs) with hybrid energy sources, which has a wide voltage gain range in the bidirectional energy flows. Compared with the traditional quasi Z source bidirectional dc dc converter, the proposed converter only changes the position of the main power switch and employs a switched capacitor cell at the output of the high voltage side. Therefore, the advantages of the wide voltage gain range and the lower voltage stresses across the power switches can be achieved. The operating principle, the voltage and current stresses across the power switches, and the comparisons with other converters are analyzed in detail. Furthermore, the parameter design of the main components, the dynamic modeling analysis, and the voltage control scheme are also presented. Finally, the experimental results obtained from a 400 W prototype validate the characteristics and the theoretical analysis of the proposed converter.", "author_names": [ "Yun Zhang", "Qiangqiang Liu", "Yongping Gao", "Jing Li", "Mark Sumner" ], "corpus_id": 54451053, "doc_id": "54451053", "n_citations": 28, "n_key_citations": 2, "score": 0, "title": "Hybrid Switched Capacitor/Switched Quasi Z Source Bidirectional DC DC Converter With a Wide Voltage Gain Range for Hybrid Energy Sources EVs", "venue": "IEEE Transactions on Industrial Electronics", "year": 2019 }, { "abstract": "A novel bidirectional dc dc converter having high voltage gain capability with high efficiency is proposed in this paper for interfacing storage in a range of applications. The proposed converter steps up (boost) the voltage in one direction while stepping it down (buck) in the other direction of operation. An attractive feature of the proposed converter is the symmetry of its operating modes. It also has inherent soft switching capability during turn on of the switches, enabling high switching frequency operation. This, coupled with the fact that the proposed converter uses only one coupled inductor for both boost and buck modes, leads to a compact system. A clamped capacitor network is used to recover the leakage energy. Circuit description, design, and loss calculations for both buck and boost modes are explained. The bidirectional converter is designed for a voltage gain of 10 and (1/10) in the boost and buck modes, respectively. A 500 W laboratory prototype of the proposed converter has been developed and tested under rated conditions. Even for a large voltage gain of 10, a peak efficiency in excess of 94% is achieved, which is not possible with conventional converters. All the results of this work are included.", "author_names": [ "Shreelakshmi M P", "Moumita Das", "Vivek Agarwal" ], "corpus_id": 59601855, "doc_id": "59601855", "n_citations": 25, "n_key_citations": 0, "score": 0, "title": "Design and Development of a Novel High Voltage Gain, High Efficiency Bidirectional DC DC Converter for Storage Interface", "venue": "IEEE Transactions on Industrial Electronics", "year": 2019 }, { "abstract": "This paper points out a phenomenon of power backflow in traditional phase shift (TPS) control of isolated bidirectional full bridge DC DC converter (IBDC) and analyzes the effects which backflow power act on power circulating flow and current stress. On this basis, the paper proposes a novel extended phase shift (EPS) control of IBDC for power distribution in microgrid. Compared with TPS control, EPS control not only expands regulating range of transmission power and enhances regulating flexibility, but also reduces current stress and improves the system efficiency. The operation principle of EPS control and the operation modes of IBDC are analyzed in the paper. By establishing mathematical models of transmission power, backflow power, and current stress, the paper comparatively analyzes control performances of TPS and EPS control. At last, experimental results verify the excellent performance of EPS control and correctness of the theoretical analysis.", "author_names": [ "Biao Zhao", "Qingguang Yu", "Weixin Sun" ], "corpus_id": 32126948, "doc_id": "32126948", "n_citations": 409, "n_key_citations": 22, "score": 0, "title": "Extended Phase Shift Control of Isolated Bidirectional DC DC Converter for Power Distribution in Microgrid", "venue": "IEEE Transactions on Power Electronics", "year": 2012 }, { "abstract": "This paper presents a novel 400 to 12 V isolated bidirectional dc dc converter based on a phase shift controlled modified dual active bridge power stage. The proposed converter consists of a half bridge and center tap with active clamp circuit, which has promising performance for low voltage high current applications. 650 V gallium nitride high electron mobility transistors are used on the high voltage side to avoid issues encountered using Si superjunction MOSFETs in phase shift controlled bidirectional power conversions. The operation principle and power transfer characteristic are obtained based on a time domain analysis of the inductor current. Design methodology and criteria and converter's efficiency analysis are discussed. Both the analysis and experiments verify that the proposed converter is capable of achieving low power loss and high power density in soft switching and hard switching modes. Experimental results are presented for a 1 kW, 400 V to 12 V dc dc prototype converter operating at 100 kHz switching frequency. A power density of 30 W/in3 and a peak efficiency of 98.3% in a wide input/output voltage range are achieved.", "author_names": [ "Fei Xue", "Ruiyang Yu", "Alex Q Huang" ], "corpus_id": 8338570, "doc_id": "8338570", "n_citations": 102, "n_key_citations": 3, "score": 0, "title": "A 98.3% Efficient GaN Isolated Bidirectional DC DC Converter for DC Microgrid Energy Storage System Applications", "venue": "IEEE Transactions on Industrial Electronics", "year": 2017 }, { "abstract": "A new transformerless bidirectional buck boost converter is proposed in this paper. The proposed converter has a simple circuit structure, low component count, low voltage stress on the power transistors, and a wide voltage gain range. This makes it applicable in the energy storage charge/discharge systems, such as electric vehicles (EV) microgrids and nanogrids with energy storage units, and uninterruptible power supplies. In addition, synchronous rectification between the complementary transistors is employed to improve the converter efficiency. A comprehensive analysis of the steady state operation, small signal model, component parameters design, and efficiency analysis of the proposed converter operating in a continuous conduction mode is given. Finally, a 1.6 kW scaled down prototype was built using Silicon Carbide MOSFETS to validate the effectiveness and feasibility of the proposed converter.", "author_names": [ "Nour Elsayad", "Hadi Moradisizkoohi", "Osama A Mohammed" ], "corpus_id": 115800953, "doc_id": "115800953", "n_citations": 28, "n_key_citations": 3, "score": 0, "title": "Design and Implementation of a New Transformerless Bidirectional DC DC Converter With Wide Conversion Ratios", "venue": "IEEE Transactions on Industrial Electronics", "year": 2019 } ]

[ { "abstract": "The latest three dimensional imaging results from Voxtel teamed with the University are Dayton are presented using Voxtel's VOX3D(tm) series flash lidar camera. This camera uses the VOX3D series flash lidar sensor which integrates a 128x128 InGaAs p i n detector array with a custom, multi mode, low noise, complementary metal oxide semiconductor readout integrated circuit. In this paper, results are presented of: short range 10 m) three dimensional lidar imaging performed at University of Dayton with a fast, low power eye safe laser (20 mJ per pulse, 10 kHz) in high bandwidth, windowed region of interest mode; and longer range (30 150 m) outdoor lidar tests performed at Voxtel with two different eye safe lasers (300 mJ and 3 mJ per pulse, 10 Hz) in full frame low bandwidth mode. The VOX3D camera achieves a single shot timing precision of 23.2 cm and 10.7 cm in high bandwidth and low bandwidth modes respectively, with the timing precision in high bandwidth mode being limited by camera electronics. The VOX3D camera has a maximum range of 51 m and 159 m with 300 mJ and 3 mJ lasers in full frame low bandwidth mode, respectively.", "author_names": [ "Cullen Philip Bradley", "Andrew D Reinhardt", "Paul F McManamon", "Vinit H Dhulla" ], "corpus_id": 155630959, "doc_id": "155630959", "n_citations": 5, "n_key_citations": 1, "score": 1, "title": "3D imaging with 128x128 eye safe InGaAs p i n lidar camera", "venue": "Defense Commercial Sensing", "year": 2019 }, { "abstract": "Silicon single photon avalanche diodes (Si SPADs) fabricated with standard CMOS technology and providing the advantages of low noise, low cost, and compatibility with additional circuits are promising candidates for single photon detection fields. The guard ring is a key component of SPADs, which prevents premature edge breakdown and improves the electric field distribution to the intended multiplication region. The choice of proper physical dimensions, especially the active radius (AR) and the size of the guard ring, is important for the better performance of Si SPADs. In this paper, a Si SPAD with a deep virtual guard ring fabricated through deep well diffusion is proposed and the effect of the physical variation of the AR and guard ring width on the device characteristics is investigated. In addition, the effect of physical variation on the device characteristics is analyzed and explained by means of technology computer aided design (TCAD) simulations.", "author_names": [ "Dongseok Shin", "Byungchoul Park", "Youngcheol Chae", "Ilgu Yun" ], "corpus_id": 164440368, "doc_id": "164440368", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "The Effect of a Deep Virtual Guard Ring on the Device Characteristics of Silicon Single Photon Avalanche Diodes", "venue": "IEEE Transactions on Electron Devices", "year": 2019 }, { "abstract": "Initial results of electrical and optical characterization of Voxtel's first generation 256 x 256 dual mode silicon singlephoton avalanche diode (SPAD) image sensor are presented. The SPAD image sensor is a dual mode device capable of sequential passive single photon counting (2D) and active single photon lidar (3D) range imaging at greater than 250 frames per second, full frame. The sensor was developed in 180 nm complementary metal oxide semiconductor imagesensor technology with a pixel pitch of 30 mm and fill factor of 9% and it achieves room temperature per pixel dark count rate of less than 55 Hz (0.63 Hz/mm2) peak photon detection probability of 29% (at 480 nm) and timing jitter of 268 ps full width at half maximum at the optimal operating point. Preliminary imaging results in 2D and 3D mode are presented.", "author_names": [ "Vinit H Dhulla", "Sapna S Mukherjee", "Adam O Lee", "Nanditha M Dissanayake", "Booshik Ryu", "C Myers" ], "corpus_id": 181524089, "doc_id": "181524089", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "256 x 256 dual mode CMOS SPAD image sensor", "venue": "Defense Commercial Sensing", "year": 2019 }, { "abstract": "", "author_names": [], "corpus_id": 131764044, "doc_id": "131764044", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "DARPA developing software reconfigurable Passive and Active LIDAR imaging sensors from ultraviolet UV through very long wave infrared VLWIR", "venue": "", "year": 2019 }, { "abstract": "Over the past 20 years, we have developed arrays of custom fabricated silicon and InP Geiger mode avalanche photodiode arrays, CMOS readout circuits to digitally count or time stamp single photon detection events, and techniques to integrate these two components to make back illuminated solid state image sensors for lidar, optical communications, and passive imaging. Starting with 4 x 4 arrays, we have recently demonstrated 256 x 256 arrays, and are working to scale to megapixel class imagers. In this paper, we review this progress and discuss key technical challenges to scaling to large format.", "author_names": [ "Brian Aull", "Erik Kurt Duerr", "Jonathan P Frechette", "K A Mcintosh", "Daniel R Schuette", "Richard D Younger" ], "corpus_id": 31094740, "doc_id": "31094740", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "Large Format Geiger Mode Avalanche Photodiode Arrays and Readout Circuits", "venue": "IEEE Journal of Selected Topics in Quantum Electronics", "year": 2018 }, { "abstract": "Abstract. An analysis is presented of the error introduced into estimates of avalanche photodiode (APD) laser rangefinder performance by assuming Gaussian distribution of the APD multiplication gain. The amplitude of current pulses emitted by an APD obeys the McIntyre distribution, the tails of which diverge from the Gaussian distribution having the same mean and variance. Because extinction of false alarms requires setting a discrimination threshold far into the tail of an analog photoreceiver's output distribution, the threshold level required to achieve a specified false alarm rate (FAR) using an APD based photoreceiver is often not accurately predicted by the standard FAR model of Rice. Characteristics of APD based photoreceivers are calculated using the McIntyre distribution and are compared with characteristics calculated using the Gaussian approximation.", "author_names": [ "Andrew S Huntington", "George M Williams", "Adam O Lee" ], "corpus_id": 55286120, "doc_id": "55286120", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Modeling false alarm rate and related characteristics of laser ranging and LIDAR avalanche photodiode photoreceivers", "venue": "", "year": 2018 }, { "abstract": "A partial calibration technique for a 128 x 128 pin diode 3D flash LIDAR camera is presented. This paper presents dark non uniformity correction (NUC) of a 3D flash LIDAR camera using dark frame subtraction. Dark frames are taken near threshold for intensity return to generate simultaneous trigger on a flash LIDAR camera, with trigger ramp set to zero for both range and intensity returns. Frames are cropped to a region of interest (ROI) and concatenated ideal dark intensity and dark range return into dark frames, processed into calibration files with nearest neighbor correction in dark intensity frames to correct out slowly varying, high intensity temporal noise when operating near threshold. Results and validation of applied NUC on 3D flash LIDAR camera are presented. We characterize a 3D flash LIDAR camera with PIN diode architecture including range walk, gain characterization in both intensity and range domains. Characterization of 3D flash LIDAR imager was performed using a fiber laser operating at 1550 nm, 20 mJ energy per pulse, TTL triggering, a pulse generator to generate time delay necessary for triggering the laser from the camera ARM signal, and an attenuator for fine control of the output signal. Time delay is relative to the range domain, whereas output signal is relative to the intensity domain.", "author_names": [ "Andrew D Reinhardt", "D Miller", "Adam O Lee", "Cullen Philip Bradley", "Paul F McManamon" ], "corpus_id": 125508392, "doc_id": "125508392", "n_citations": 4, "n_key_citations": 1, "score": 0, "title": "Dark non uniformity correction and characterization of a 3D flash lidar camera", "venue": "Defense Security", "year": 2018 }, { "abstract": "Optical communication is becoming more prevalent in orbit due to the need for increased data throughput. Nanosatellites, which are satellites that typically weigh less than 10 kg, are also becoming more common due to lower launch costs that enable the rapid testing of technology in a space environment. Nanosatellites are cheaper to launch than their larger counterparts and may be a viable option for communicating beyond Earth's orbit, but have strict Size, Weight, and Power (SWaP) requirements. The Miniature Optical Communication Transceiver (MOCT) is a compact optical transceiver designed to provide modest data rates to SWaP constrained platforms, like nanosatellites. This paper will cover the optical amplifier characterization and simulated performance of the MOCT amplifier design that produces 1 kW peak power pulses and closes three optical links which include Low Earth Orbit (LEO) to Earth, LEO to LEO, and Moon to Earth. Additionally, a benchtop version of the amplifier design was constructed and was able to produce amplified pulses with 1.37 W peak power, including a 35.7% transmit optics loss, at a pump power of 500 mW. Finally, the modulator, seed laser, amplifier, receiver, and time to digital converter were all used together to measure the Bit Error Ratio (BER) which was 0.00257 for a received optical peak power of 176 nW.", "author_names": [ "Nathan S Barnwell", "Tyler Ritz", "Samantha Parry", "Myles Clark", "Paul C Serra", "John W Conklin" ], "corpus_id": 59347336, "doc_id": "59347336", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "The Miniature Optical Communication Transceiver A Compact, Power Efficient Lasercom System for Deep Space Nanosatellites", "venue": "", "year": 2018 }, { "abstract": "The effective range of a laser rangefinder (LRF) depends on the sensitivity of its photoreceiver and the strength of optical signal returns as a function of target range. Parameters affecting signal return strength are reviewed, including laser pulse energy, atmospheric conditions, and the size, orientation, and surface properties of the target.", "author_names": [ "George M Williams", "Andrew S Huntington" ], "corpus_id": 201054154, "doc_id": "201054154", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Laser Rangefinder Effective Range", "venue": "", "year": 2018 }, { "abstract": "Deep convection at mid latitudes can directly inject water vapor into the upper troposphere/lower stratosphere (UTLS) Increased water vapor creates a photochemical environment that can activate inorganic chlorine (HCl) which then catalytically destroys ozone, increasing health and environment risk [1] The Laser Crosslink Atmospheric Sounder (LCAS) is a prototype toward a low Earth orbiting (LEO) constellation to concurrently measure both UTLS water vapor and temperature at high vertical resolution, improving temporal and spatial coverage. The two part approach uses both beam pointing and intensity. First, precision pointing measures atmospheric refraction and can be used to obtain temperature profiles [2] Second, intensity on the continuum and near absorption features of the spectrum can measure water vapor concentration. This work presents demonstration using near infrared laser crosslinks wavelengths in ITU S (1460 nm to 1530 nm) and ITU C (1530 nm to 1565 nm) bands for measurement of water vapor, where commercial components already exist for applications like coarse wavelength division multiplexing (CWDM) over terrestrial optical fiber. We use MODTRAN to assess the measurability of varying concentrations of water vapor in the UTLS in these bands. We find that 1550 nm is a suitable continuum reference wavelength, and that 1504 and 1509 nm have detectable changes in transmissivity with increases in water vapor.", "author_names": [ "Cadence Payne", "Angela Crews", "Kerri L Cahoy", "Daniel James Cziczo", "John W Conklin", "Michael Hart", "Gottfried Kirchengaast", "Nicolas Fraunhofer" ], "corpus_id": 55378194, "doc_id": "55378194", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Laser Crosslink Atmospheric Sounder to Investigate the Effects of Deep Convection on Ozone", "venue": "", "year": 2018 } ]

[ { "abstract": "We have fabricated organic thin film transistors, inverters, and ring oscillators on glass and on flexible polyethylene naphthalate, using the small molecule hydrocarbon pentacene as the semiconductor and solution processed polyvinylphenol as the gate dielectric. Depending on the choice of substrate, the transistors have a carrier mobility between 0.3 and 0.7 cm2/V s, an on/off current ratio between 105 and 106, and a subthreshold swing between 0.9 and 1.6 V/decade. To account for the positive switch on voltage of the transistors, circuits were designed to operate with integrated level shifting. Depending on the type of substrate, ring oscillators have a signal propagation delay as low as 15 ms per stage.", "author_names": [ "Hagen Klauk", "Marcus Halik", "Ute Zschieschang", "Florian Eder", "Gunter Schmid", "Christine Dehm" ], "corpus_id": 109208406, "doc_id": "109208406", "n_citations": 308, "n_key_citations": 0, "score": 1, "title": "Pentacene organic transistors and ring oscillators on glass and on flexible polymeric substrates", "venue": "", "year": 2003 }, { "abstract": "The phototransistor properties of pentacene organic transistors with a poly(methyl methacrylate) dielectric layer have been investigated. It was found that as the intensity of incident light increased, drain current gradually increased and threshold voltage shifted by degrees towards the positive direction, because of the higher number of more photons provided by incident light with a high intensity leading to a higher carrier density in the channel. Moreover, the prepared organic transistors showed a photocurrent response opposite to the absorption spectrum of pentacene. The photoresponse time of the pentacene transistor was determined to be shorter than 0.03 s.", "author_names": [ "Yan Hu", "Guifang Dong", "Liduo Wang", "Yong Qiu" ], "corpus_id": 119741662, "doc_id": "119741662", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Phototransistor Properties of Pentacene Organic Transistors with Poly(methyl methacrylate) Dielectric Layer", "venue": "", "year": 2006 }, { "abstract": "Blending organic semiconductors with insulating polymers has been known to be an effective way to overcome the disadvantages of single component organic semiconductors for high performance organic field effect transistors (OFETs) We show that when a solution processable organic semiconductor (6,13 bis(triisopropylsilylethynyl)pentacene, TIPS pentacene) is blended with an insulating polymer (PS) morphological and structural characteristics of the blend films could be significantly influenced by the processing conditions like the spin coating time. Although vertical phase separated structures (TIPS pentacene top/PS bottom) were formed on the substrate regardless of the spin coating time, the spin time governed the growth mode of the TIPS pentacene molecules that phase separated and crystallized on the insulating polymer. Excess residual solvent in samples spun for a short duration induces a convective flow in the drying droplet, thereby leading to one dimensional (1D) growth mode of TIPS pentacene crystals. In contrast, after an appropriate spin coating time, an optimum amount of the residual solvent in the film led to two dimensional (2D) growth mode of TIPS pentacene crystals. The 2D spherulites of TIPS pentacene are extremely advantageous for improving the field effect mobility of FETs compared to needle like 1D structures, because of the high surface coverage of crystals with a unique continuous film structure. In addition, the porous structure observed in the 2D crystalline film allows gas molecules to easily penetrate into the channel region, thereby improving the gas sensing properties.", "author_names": [ "Jung Hun Lee", "Yena Seo", "Yeong Don Park", "John E Anthony", "Donghoon Kwak", "Jung Ah Lim", "Sung Lim Ko", "Ho Won Jang", "Kilwon Cho", "Wi Hyoung Lee" ], "corpus_id": 58004917, "doc_id": "58004917", "n_citations": 49, "n_key_citations": 1, "score": 0, "title": "Effect of Crystallization Modes in TIPS pentacene/Insulating Polymer Blends on the Gas Sensing Properties of Organic Field Effect Transistors", "venue": "Scientific Reports", "year": 2019 }, { "abstract": "N Heterocyclic carbenes (NHCs) which react with the surface of Au electrodes, have been successfully applied in pentacene transistors. With the application of NHCs, the charge carrier mobility of pentacene transistors increased by five times, while the contact resistance at the pentacene Au interface was reduced by 85 Even after annealing the NHC Au electrodes at 200 degC for 2 h before pentacene deposition, the charge carrier mobility of the pentacene transistors did not decrease. The distinguished performance makes NHCs as excellent alternatives to thiols as metal modifiers for the application in organic field effect transistors (OFETs)", "author_names": [ "Aifeng Lv", "M Freitag", "Kathryn M Chepiga", "Andreas H Schafer", "Frank Glorius", "Lifeng Chi" ], "corpus_id": 3366327, "doc_id": "3366327", "n_citations": 33, "n_key_citations": 0, "score": 0, "title": "N Heterocyclic Carbene Treated Gold Surfaces in Pentacene Organic Field Effect Transistors: Improved Stability and Contact at the Interface.", "venue": "Angewandte Chemie", "year": 2018 }, { "abstract": "Abstract Flexible organic field effect transistors with high electrical stability upon bending are demonstrated on indium tin oxide coated polyethylene terephthalate substrates with TIPS Pentacene semiconductor crystals formed by drop casting on a hybrid gate dielectric consisting hafnium dioxide grown by atomic layer deposition and spin coated poly(4 vinylphenol) Fabricated devices exhibited excellent p channel characteristics with field effect mobility up to 0.12 cm2/Vs with high current on/off ratio >104 and low threshold voltage of 0.2 V. Device performance was slightly affected by mechanical strain applied by bending for 5 min with radius varying from 12.5 mm to as low as 5.0 mm; and a high stability in performance was demonstrated upon applying constant tensile strain for more than 48 h at bending radius of 5.0 mm. It was found that strain induced changes in the device performance primarily occur due to increase in dielectric surface roughness; and the semiconductor dielectric interface uniformity is influenced more with magnitude of strain rather than its duration.", "author_names": [ "Vivek Raghuwanshi", "Deepak Bharti", "Shree Prakash Tiwari" ], "corpus_id": 100623589, "doc_id": "100623589", "n_citations": 38, "n_key_citations": 1, "score": 0, "title": "Flexible organic field effect transistors with TIPS Pentacene crystals exhibiting high electrical stability upon bending", "venue": "", "year": 2016 }, { "abstract": "Abstract 6,13 bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) from simple drop casting typically forms crystals with random orientation and poor areal coverage, which leads to device to device performance variation of organic thin film transistors (OTFTs) Previously, a temperature gradient technique was developed to address these problems. However, this approach simultaneously introduced thermal cracks due to the thermally induced stress during crystallization. These thermal cracks accounted for a reduction of charge transport, thereby impacting the device performance of TIPS pentacene based OTFTs. In this work, an insulating polymer, poly(a methyl styrene) (PaMS) was blended with TIPS pentacene to relieve the thermal stress and effectively prevent the generation of thermal cracks. The results demonstrate that the incorporation of PaMS polymer combined with the temperature gradient technique improves both the hole mobility and performance consistency of TIPS pentacene based OTFTs.", "author_names": [ "Kyeiwaa Asare-Yeboah", "Sheng Bi", "Zhengran He", "Dawen Li" ], "corpus_id": 28186748, "doc_id": "28186748", "n_citations": 36, "n_key_citations": 1, "score": 0, "title": "Temperature gradient controlled crystal growth from TIPS pentacene poly(a methyl styrene) blends for improving performance of organic thin film transistors", "venue": "", "year": 2016 }, { "abstract": "Abstract Flexible organic field effect transistors (OFETs) with TIPS pentacene: polystyrene (PS) blend are demonstrated to exhibit enhanced mobility and significantly improved electrical stability compared to neat TIPS pentacene on poly(4 vinylphenol) (PVP) dielectric (bi layer OFETs) along with high mechanical stability. Due to merit of high quality dielectric semiconductor interface, pristine TIPS pentacene: PS blend OFETs exhibited maximum mobility of 0.93 cm2 V 1 s 1 with average of 0.44( 0.25) cm2 V 1 s 1 compared to 0.14( 0.10) cm2 V 1 s 1 for bi layer OFETs with high current on off ratios on the order 105 for both. Both types of devices exhibited high electrical stability upon bending with increasing magnitude of strain or its duration up to 5 days. However, significant differences in electrical stability of devices were observed upon applying constant bias stress for 40 min to 1 h. Pristine blend devices exhibited outstanding electrical stability with very low drain current decay of", "author_names": [ "Vivek Raghuwanshi", "Deepak Bharti", "Ishan Varun", "Ajay Kumar Mahato", "Shree Prakash Tiwari" ], "corpus_id": 102182146, "doc_id": "102182146", "n_citations": 30, "n_key_citations": 1, "score": 0, "title": "Performance enhancement in mechanically stable flexible organic field effect transistors with TIPS pentacene:polymer blend", "venue": "", "year": 2016 }, { "abstract": "Pentacene based organic thin film transistors (OTFTs) were fabricated on several types of flexible substrate: commercial photo paper, ultra smooth specialty paper and ultra thin (100 mM) flexible glass. The transistors were fabricated entirely through dry step processing. The transconductance and field effect mobility of OTFTs on photo paper reached values of ~0.52 mS m( 1) and 0.1 cm(2) V 1) s( 1) respectively. Preliminary results on the lifetime of OTFTs on photo paper yielded stable transconductance and mobility values over a period of more than 250 h. The comparable characteristics of OTFTs fabricated on widely available, low cost paper and high quality expensive liquid crystal display glass indicate the potential importance of cellulose based electronic devices.", "author_names": [ "Adam T Zocco", "Han You", "Joshua A Hagen", "Andrew J Steckl" ], "corpus_id": 3841416, "doc_id": "3841416", "n_citations": 47, "n_key_citations": 0, "score": 0, "title": "Pentacene organic thin film transistors on flexible paper and glass substrates.", "venue": "Nanotechnology", "year": 2014 }, { "abstract": "In this work, we report for the first time the use of a nonconjugated semicrystalline polymer as a film forming agent to control the crystallization and tune the charge transport of solution processed, small molecule organic semiconductors. When 6,13 bis (triisopropylsilylethynyl) pentacene (TIPS pentacene) was demonstrated as a representative material to blend with polyethylene oxide (PEO) polymer, it crystallized into uniformly aligned needles with reduced random orientation, enhanced long range order and elevated areal coverage. Specifically, an ultra low misorientation angle of 7.9deg 3.5deg was obtained with 10% PEO additive, beneficial for charge transport in the TIPS pentacene/PEO hybrid film. Bottom gate, top contact organic thin film transistors (OTFTs) based on TIPS pentacene/PEO mixture were found to show a field effect mobility up to 2.5 x 10 2 cm 2 /Vs. This work may be universally applied to other organic semiconductors to regulate their crystal formation, enhance film forming and improve device performance of OTFTs. It contributes to the utilization of flexible substrates for future generation high performance organic electronics.", "author_names": [ "Zhengran He", "Ziyang Zhang", "Sheng Bi", "Kyeiwaa Asare-Yeboah", "Jihua Chen" ], "corpus_id": 211539072, "doc_id": "211539072", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Ultra low misorientation angle in small molecule semiconductor/polyethylene oxide blends for organic thin film transistors", "venue": "Journal of Polymer Research", "year": 2020 }, { "abstract": "Flexible ammonia (NH3) gas sensors based on solution processable organic thin film transistors (OTFTs) are fabricated using a TIPS pentacene active layer/PMMA dielectric layer on glass and plastic substrates. These OTFT sensors exhibit outstanding NH3 gas response and recovery characteristics under multiple exposure/evacuation cycles at controlled NH3 concentrations.", "author_names": [ "Xinge Yu", "Nanjia Zhou", "Shijiao Han", "Hui Li Lin", "Donald B Buchholz", "Junsheng Yu", "R P H Chang", "Tobin J Marks", "Antonio F Facchetti" ], "corpus_id": 96361586, "doc_id": "96361586", "n_citations": 97, "n_key_citations": 0, "score": 0, "title": "Flexible spray coated TIPS pentacene organic thin film transistors as ammonia gas sensors", "venue": "", "year": 2013 } ]

[ { "abstract": "Abstract The metal oxide semiconductor field effect transistor (MOSFET) is scaling to a \"tunneling epoch\" in which multiple leakage current induced by different tunneling effects exist. The complementary Si based tunneling transistors are presented in this paper. The working principle of this device is investigated in detail. It is found that the band to band tunneling current is be controlled by the gate to source voltage. Due to the reverse biased p i n diode structure, an ultra low leakage current is achieved. The sub threshold swing of TFET is not limited by kt/q, which is the physical limit of the MOSFET. Using the CMOS compatible processes, the complementary TFETs (CTFET) are fabricated on one wafer. From a circuit point of view, the compatibility between TFET and MOSFET enables the transfer of CMOS circuits to CTFET circuits.", "author_names": [ "Pengfei Wang", "K Hilsenbeck", "Thomas Nirschl", "M Oswald", "Christoph Stepper", "M Weis", "Doris Schmitt-Landsiedel", "Walter Hansch" ], "corpus_id": 98651558, "doc_id": "98651558", "n_citations": 358, "n_key_citations": 8, "score": 1, "title": "Complementary tunneling transistor for low power application", "venue": "", "year": 2004 }, { "abstract": "One of the major roadblocks to further scaling of complementary metal oxide semiconductor (CMOS) devices is power consumption. Reduction of power consumption requires low operation voltage, which requires low threshold voltage. In order to decrease the threshold voltage without excessive increase of OFF current, reduction of the subthreshold swing is essential. To reduce the subthreshold swing, various carrier injection mechanisms other than thermal carrier injection have been proposed. Currently, interband tunneling is the most promising mechanism and the device that utilizes such a mechanism is a tunneling field effect transistor (TFET) After the introduction to the fundamentals of TFETs, various approaches to increase the drain current of Si TFETs by device structure engineering are described. The last section focuses on bandgap engineering to enhance the drain current of TFETs.", "author_names": [ "Byung-Gook Park" ], "corpus_id": 109042598, "doc_id": "109042598", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Tunneling Field Effect Transistors for Ultra Low Power Application", "venue": "", "year": 2016 }, { "abstract": "The continuous down scaling of transistors has been the key to the successful development of current information technology. However, with Moore's law reaching its limits, the development of alternative transistor architectures is urgently needed 1 Transistors require a switching voltage of at least 60 mV for each tenfold increase in current, that is, a subthreshold swing (SS) of 60 mV per decade (dec) Alternative tunnel field effect transistors (TFETs) are widely studied to achieve a sub thermionic SS and high I 60 (the current where SS becomes 60 mV dec 1 2 Heterojunction (HJ) TFETs show promise for delivering a high I 60 but experimental results do not meet theoretical expectations due to interface problems in the HJs constructed from different materials. Here, we report a natural HJ TFET with spatially varying layer thickness in black phosphorus without interface problems. We have achieved record low average SS values over 4 5 dec of current (SS ave_4dec ~22.9 mV dec 1 and SS ave_5dec ~26.0 mV dec 1 with record high I 60 I 60 0.65 1 mA mm 1 paving the way for application in low power switches. Tunnel field effect transistors with spatially varying layer thickness in black phosphorus enable high performance with a record low subthreshold swing.", "author_names": [ "Seungho Kim", "Gyuho Myeong", "Wongil Shin", "Hongsik Lim", "Boram Kim", "Taehyeok Jin", "Sungjin Chang", "Kenji Watanabe", "Takashi Taniguchi", "Sungjae Cho" ], "corpus_id": 210839043, "doc_id": "210839043", "n_citations": 45, "n_key_citations": 0, "score": 0, "title": "Thickness controlled black phosphorus tunnel field effect transistor for low power switches", "venue": "Nature Nanotechnology", "year": 2020 }, { "abstract": "Conventional field effect transistors (FETs) have long been considered a fundamental electronic component for a diverse range of devices. However, nanoelectronic circuits based on FETs are not energy efficient because they require a large supply voltage for switching applications. To reduce the supply voltage in standard FETs, which is hampered by the 60 mV/decade limit established by the subthreshold swing (SS) a new class of FETs have been designed, tunnel FETs (TFETs) A TFET utilizes charge carrier transportation in device channels using quantum mechanical based band to band tunneling despite of conventional thermal injection. The TFETs fabricated with thin semiconducting film or nanowires can attain a 100 fold power drop compared to complementary metal oxide semiconductor (CMOS) transistors. As a result, the use of TFETs and CMOS technology together could ameliorate integrated circuits for low power devices. The discovery of two dimensional (2D) materials with a diverse range of electronic properties has also opened new gateways for condensed matter physics, nanotechnology, and material science, thus potentially improving TFET based devices in terms of device design and performance. In this review, state of art TFET devices exhibiting different semiconducting channels and geometries are comprehensively reviewed followed by a brief discussion of the challenges that remain for the development of high performance devices. Lastly, future prospects are presented for the improvement of device design and the working efficiency of TFETs.", "author_names": [ "Ghazanfar Nazir", "Adeela Rehman", "Soo-Jin Park" ], "corpus_id": 221619378, "doc_id": "221619378", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Energy efficient tunneling field effect transistors for low power device applications: challenges and opportunities.", "venue": "ACS applied materials interfaces", "year": 2020 }, { "abstract": "In order to decrease the threshold voltage while maintaining the OFF current low, reduction of the subthreshold swing is essential in field effect transistors(FETs) To reduce the subthreshold swing below 60 mV/decade, inter band tunneling can be used for injection of carriers and the device that utilizes such a mechanism is tunneling field effect transistor (TFET) Silicon(Si) TFETs, which are favored due to their compatibility with currently dominant complementary metal oxide semiconductor(CMOS) technology, suffer from low ON current because of the relatively large bandgap of Si. The ON current of Si TFETs can be increased by field and area enhancement in a cylindrical nanowire channel. Numerical analysis has confirmed that the cylindrical channel structure shows significantly higher tunneling rate and wider tunneling area than the double gate structure. Si TFETs with a hemicylindrical nanowire channel are fabricated and characterized, and the effectiveness of nanowire channel approach is demonstrated.", "author_names": [ "Byung-Gook Park", "Min-Chul Sun", "Sang Wan Kim" ], "corpus_id": 112728495, "doc_id": "112728495", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Silicon Tunneling Field Effect Transistors with a Hemicylindrical Nanowire Channel for Ultra Low Power Application", "venue": "", "year": 2014 }, { "abstract": "The present research letter is dedicated to a detailed analysis of a double gate tunnel field effect transistor (DG TFET) The DG TFET provides improved on current (ION) than a conventional TFET via bandto band (B2B) tunneling. However, DG TFET is disadvantageous for low power applications because of increased off current (IOFF) due to the large ambipolar current (Iamb) In this research work, a Si/GaAs/ GaAs heterostructure DG TFET is considered as research base for investigation of device performance. The electrical parameters of the DG TFET device have been improved in comparison to the homostructure. The transfer (I V) characteristics, capacitance voltage (C V) characteristic of homo structure Si/ Si/Si and hetero structure Si/GaAs/GaAs, DG TFET both structures is analysed comparatively. The C V characteristics of DG TFET have obtained using operating frequency of 1 MHz. The ambipolar current Iamb is suppressed by 5 x 108 order of magnitude in proposed Si/GaAs/GaAs hetero DG TFET as compared to Si/Si/Si homo DG TFET up to the applied drain voltage very low equal to VDS 0.5 V without affecting onstate performance. The simulation result shows a very good ION/IOFF ratio (10 13) and low subthreshold slope, SS ~36.52 mV/dec) The various electrical characteristics of homo and hetero DGTFET such as on current (ION) off current (IOFF) time delay (id) transconductance (gm) and power delay product (PDP) have been improve in Si/GaAs/GaAs heterostructure DG TFET and compared with Si/Si/ Si homo DG TFET. The advantageous results obtained for the proposed design show its usability in the field of digital and analog applications.", "author_names": [ "N Guenifi", "Rahi Sb", "Mohamed Amine Larbi" ], "corpus_id": 221296070, "doc_id": "221296070", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Suppression of Ambipolar Current and Analysis of RF Performance in Double Gate Tunneling Field Effect Transistors for Low Power Applications", "venue": "", "year": 2020 }, { "abstract": "Junctionless transistors (JLT) are a promising alternative to address the stringent junction requirements in conventional transistors. However, JLTs are plagued by high OFF state leakage current attributed to the band to band tunneling at the channel drain interface. This leakage current is often referred to as gate induced drain leakage (GIDL) In this paper, we propose an effective technique to suppress GIDL in JLTs. We use the charge plasma concept to realize an electrostatically doped drain (EDD) separated from the channel by an intermediate intrinsic region. Therefore, the proposed EDD JLT is an n+ n+ i n+ structure that widens the tunnel barrier at the gate drain interface in the OFF state (VGS 0 V, VDS 1 V) and offers significant reduction in leakage current. We compare, using 2D TCAD device simulations, the EDD JLT with the conventional JLT in terms of various digital and analog performance metrics. We observe that EDD JLTs of gate length 20 nm offer a significant reduction in IOFF 4 orders) while substantially improving ION/IOFF ratio 4 orders) as compared to conventional JLTs. To study the scalability of the proposed technique, the device thickness and gate length were scaled down to 5 nm. We observe that even for scaled down structure, EDD JLTs retain their performance benefit. We observe that the analog performance metrics such as intrinsic gain (GmRo) transconductance generation factor (Gm/ID) output conductance (GD) channel length modulation, and drain induced barrier lowering of EDD JLTs are also significantly improved as compared to conventional JLTs.", "author_names": [ "Mohd Adil Raushan", "Naushad Alam", "M J Siddiqui" ], "corpus_id": 146093468, "doc_id": "146093468", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Electrostatically doped drain junctionless transistor for low power applications", "venue": "Journal of Computational Electronics", "year": 2019 }, { "abstract": "In this work, we design and analyze complementary metal oxide semiconductor (CMOS) compatible III V compound electron hole bilayer (EHB) tunneling field effect transistors (TFETs) by using two dimensional (2D) technology computer aided design (TCAD) simulations. A recently proposed EHB TFET exploits a bias induced band to band tunneling (BTBT) across the electron hole bilayer by an electric field from the top and bottom gates. This is in contrast to conventional planar p( p( n TFETs, which utilize BTBT across the source to channel junction. We applied III V compound semiconductor materials to the EHB TFETs in order to enhance the current drivability and switching performance. Devices based on various compound semiconductor materials have been designed and analyzed in terms of their primary DC characteristics. In addition, the operational principles were validated by close examination of the electron concentrations and energy band diagrams under various operation conditions. The simulation results of the optimally designed In0.533Ga0.47As EHB TFET show outstanding performance, with an on state current (Ion) of 249.5 mA/mm, subthreshold swing (S) of 11.4 mV/dec, and threshold voltage (Vth) of 50 mV at VDS 0.5 V. Based on the DC optimized InGaAs EHB TFET, the CMOS inverter circuit was simulated in views of static and dynamic behaviors of the p channel device with exchanges between top and bottom gates or between source and drain electrodes maintaining the device structure.", "author_names": [ "Sung Yoon Kim", "Jae Hwa Seo", "Young Jun Yoon", "Ho-young Lee", "Seong Min Lee", "Seongjae Cho", "In Man Kang" ], "corpus_id": 25257825, "doc_id": "25257825", "n_citations": 3, "n_key_citations": 1, "score": 0, "title": "Design and Analysis of CMOS Compatible III V Compound Electron Hole Bilayer Tunneling Field Effect Transistor for Ultra Low Power Applications.", "venue": "Journal of nanoscience and nanotechnology", "year": 2015 }, { "abstract": "A novel vertical channel face tunneling field effect transistor (VC TFET) using Ge/SiGe material is proposed in this paper. The proposed device structure enhances the on state drive current without increasing the device footprint and also provides lower off state leakage current, steeper sub threshold slope and higher $I_{on}/I_{off} current ratio compared to the other TFETs. The design of SiGe material in the drain region suppresses the leakage current, and the channel region with small bandgap Ge enhances the tunneling current. Additionally, the complementary vertical channel TFET is also used to demonstrate the SRAM circuit performance for low power application. Novel SRAM topologies are proposed to eliminate the read disturb and enhance the RSNM/WSNM of SRAM.", "author_names": [ "Akancha Gupta", "Chen Kuo Chiang", "W Y Yang", "E R Hsieh", "S Chung" ], "corpus_id": 221913681, "doc_id": "221913681", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Design of Low Voltage Vertical Channel Face tunneling TFET Using Ge/SiGe Materials and Its SRAM Circuit Performance", "venue": "2020 International Symposium on VLSI Technology, Systems and Applications (VLSI TSA)", "year": 2020 }, { "abstract": "The two dimensional (2D) vertical van der Waals (vdW) stacked homojunction is an advantageous configuration for fast low power tunneling field effect transistors (TFETs) We simulate the device performance of the sub 10 nm vertical SnSe homojunction TFETs with ab initio quantum transport calculations. The vertically stacked device configuration has an effect of decreasing leakage current when compared with its planar counterpart due to the interrupted carrier transport path by the broken connection. A subthreshold swing over four decades (SSave_4 dec) of 44.2 45.8 mV dec 1 and a drain current at SS 60 mV dec 1 (I60) of 5 7 mA mm 1 are obtained for the optimal vertical SnSe homojunction TFET with Lg 10 nm at a supply voltage of 0.5 0.74 V. In terms of the device's main figures of merit (i.e. on state current, intrinsic delay time, and power delay product) the vertical SnSe TFETs and NCTFETs outperform the 2022 and 2028 targets of the International Technology Roadmap for Semiconductors requirements for low power application (2013 version) respectively.", "author_names": [ "Huanqiao Li", "Jiakun Liang", "Peipei Xu", "Jingyao Luo", "Fengbin Liu" ], "corpus_id": 225881224, "doc_id": "225881224", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Vertically stacked SnSe homojunctions and negative capacitance for fast low power tunneling transistors", "venue": "", "year": 2020 } ]

[ { "abstract": "In this paper, the interaction between chip and package is investigated. A series of experiments are conducted to investigate the effect of the package type on occurrence of passivation cracks in IC structures. Virtual prototyping is used to generate more accurate and efficient stress design rules for IC backend structures, in combination with packaging processes and geometry. The addressed failure mode of passivation cracks is found to depend on the package type or family: for exposed pad packages this failure mode is easier to occur. It is demonstrated that for successful development of IC backend structures and processes, it is essential to take into account the influence of the package in the earlier phase of IC backend development. The so called integral design rules, accounting for all the major loading sources and history of the complete product creation process has to be used for the development of new generation semiconductors devices.", "author_names": [ "Willem D van Driel", "Dao-Guo Yang", "G Q Zhang" ], "corpus_id": 38750478, "doc_id": "38750478", "n_citations": 6, "n_key_citations": 0, "score": 1, "title": "On chip package stress interaction", "venue": "Microelectron. Reliab.", "year": 2008 }, { "abstract": "In this paper, CPI (chip package interaction) reliability of WLP (wafer level package) was investigated. PBO (Polybenzoxazole) based RDL (redistribution layer) structure was the primary focus. Firstly, the stress distribution for PBO structures was studied by simulation. Secondly, two types of the chip with different PBO structures completed the accelerating experiments. Based on our investigation, the results of CPI reliability tests are coincident with the simulation data. It can be applied to the early prediction for the risk level of CPI reliability. Additionally, failure mechanisms were figured out for different PBO structures. Design A has the potential risk to suffer corrosion damage owing to exposed SR (seal ring) and CAS (crack stop) Design B has a four times failure rate in THT (Temperature and Humidity Test) which related to hotspots around SR. These results suggest that protecting SR and relieving hotspots effect will effectively enhance CPI reliability performance of WLP.", "author_names": [ "Chong Qin", "Ying Li", "Haiyang Mao" ], "corpus_id": 221568051, "doc_id": "221568051", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Effect of Different PBO Based RDL Structures on Chip Package Interaction Reliability of Wafer Level Package", "venue": "IEEE Transactions on Device and Materials Reliability", "year": 2020 }, { "abstract": "Microelectronic components used in automotive applications have to meet very strict reliability requirements. In addition to the mechanical or thermomechanical stresses resulting from manufacturing and application conditions, also chemical processes have to be considered if the systems are exposed to harsh environmental conditions. In these cases, mechanical stresses do not only determine the risk of deformation induced failure and cracking but can also affect the diffusion kinetics of any chemical species, e.g. humidity and corrosive compounds. This paper addresses chip package interaction effects that determine the probability of chip damage by corrosion. The effects of mechanical stress resulting from both the package and from additional external loading on humidity diffusion kinetics, and finally on the resulting failure probability were investigated using finite element analysis (FEA) The simulation results were compared to the experimentally determined failure risk. Further the derived numerical results showed a distinct correlation with the experimentally detected failure risks provoked by different accelerated reliability tests. To validate the correlation between stress supported diffusion and the occurrence of corrosive failures, a specific dedicated experimental test setup was created. The results showed a very good correlation of corrosive failure modes in the active die structures to the mechanical stresses at the critical regions determined from the accompanying FEA package simulation. In addition, scanning electron microscope investigations revealed that the corrosive chip damage started at locations that were also in accordance with the simulation results.", "author_names": [ "G Lorenz", "Michel Simon-Najasek", "A Lindner" ], "corpus_id": 7001437, "doc_id": "7001437", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "The Combined Effect of Mechanical Package Stress and Humidity on Chip Corrosion Probability", "venue": "2017 IEEE 67th Electronic Components and Technology Conference (ECTC)", "year": 2017 }, { "abstract": "Novel approach for assessment of the effect of temperature and chip package interaction (CPI) induced stress on performance and reliability of ICs with 2.5D/3D architectures is presented. A developed physics based model and a multiphysics EDA tool prototype analyze thermal, and thermomechanical problems during package assembly and chip operation. The tool employs effective anisotropic thermalmechanical properties methodology that accurately represents non uniformity within a die or a layer, and significantly boosts computational performance by avoiding complex geometries. An implemented link between layout analysis tools and the multiphysics thermal mechanical tool enables to perform reliability check within the design flow. The developed stress simulation flow takes into account multiscale stress variations from a package macro scale to an interconnect segment and transistor nano scale. The obtained across chip temperature and stress fields are used for calculating the variations in transistors electrical characteristics, and for analysis of potential cracking locations in the interconnect layers.", "author_names": [ "Valeriy Sukharev", "Armen Kteyan", "Jun-Ho Choy" ], "corpus_id": 215739511, "doc_id": "215739511", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "An Accurate Assessment of Chip Package Interaction is a Key Factor for Designing Resilient 3D IC Systems", "venue": "2019 International 3D Systems Integration Conference (3DIC)", "year": 2019 }, { "abstract": "Abstract Distinct temperature and process dependent deformation behaviors under packaging temperature cycles are characterized for various packaging materials. Substrate and underfill deformations are described using Maxwell viscoelasticity model. Solder bump deformation is represented by incremental plasticity model. Anisotropic deformation in silicon and orthotropic deformation in substrate are also considered. The material deformation effects on stress evolutions during fabrication and under chip package interaction (CPI) are analyzed for a large package structure. Complex geometries spread over a large range of length scales are simulated using multi level and multiscale sequential submodeling technique. Global package simulations show that substrate orthotropy has a significant impact on the package warpage during the assembly process. Sequential package assembly simulations are performed to examine the residual stresses at package, bump and interconnect scales. The results show that the package mate.", "author_names": [ "Aditya P Karmarkar", "Xiaopeng Xu", "Karim Gamal El-Sayed" ], "corpus_id": 139472589, "doc_id": "139472589", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Temperature and Process Dependent Material Characterization and Multiscale Stress Evolution Analysis for Performance and Reliability Management under Chip Package Interaction", "venue": "", "year": 2017 }, { "abstract": "To enable higher computing power in a single chip, there is demand for increasing die size for high performance applications in advanced nodes. Due to the weak mechanical properties of the low k and ultra low k (ULK) dielectrics in advanced technology nodes, the backend of line (BEOL) stacks are more prone to thermal mechanical failures, resulting in increased semiconductor assembly processes and reliability challenges. This is further exacerbated by the transition of lead (Pb) based solders to Pb free solders (higher melting temperatures) as well as the transition to copper pillar bump (less malleable deformable) These changes bring more package stress which can potentially be transferred to the BEOL stack, increasing chip package interaction (CPI) failure risks. With the increased distance to neutral point (DNP) in large dies, the package to die stress also increases significantly. Therefore, CPI risks in large die applications in advanced nodes are especially challenging. This paper discusses in detail the different CPI reliability challenges of large dies with size up to 25mm x 25mm in flip chip ball grid array (fcBGA) packages in an advanced CMOS technology node. One of the key findings from this study is the impact of kerf width (crack stop to crack stop distance) on CPI performance. While it is well known that narrow kerfs are more subject to dicing damage risks, it is less recognized that wide kerf poses unique CPI challenges. Both narrow and wide kerf were assessed in this work. It is observed that narrow and wide kerf can drive different failure mechanisms. A wide kerf is especially challenging for CPI due to increased energy release rate of cracks if present. By understanding the physics and mechanics of failures, key CPI sensitive parameters can be defined to ensure products are robust to successfully meet various industry standard CPI stress qualification.", "author_names": [ "Zhuo-Jie Wu", "Charles Carey", "Samantha Donavan", "Doug Hunt", "Patrick Justison", "Theo Anemikos", "John Cincotta", "Hugues C Gagnon", "Oswaldo Chacon", "Robert Martel", "Thomas A Wassick" ], "corpus_id": 51969926, "doc_id": "51969926", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Chip Package Interaction Challenges for Large Die Applications", "venue": "2018 IEEE 68th Electronic Components and Technology Conference (ECTC)", "year": 2018 }, { "abstract": "Chip package interaction (CPI) is a key area for achieving robust copper bump interconnection in flip chip packages. Polyimide (PI) has been widely used in electronic package products to provide structural support to protect electronic devices from excessive stress. Passivation crack and LK/ELK delamination are two polyimide related failures in flip chip packages and pose significant challenges to achieving robust CPI design. A 3D finite element model was developed to evaluate the stress impact with the role of polyimide. For the passivation crack, a failure metric, radial passivation stress has been proposed to understand the passivation crack risk. The simulation shows that the in plane radial stress of passivation layer is well correlated with the test results. The location of passivation crack matches the peak radial stress location within the passivation layer. The simulation compared the in plane radial stress between package with and without PI and found the in plane radial stress of passivation of packages with PI was significantly reduced compared with packages without PI layer. The simulation demonstrates PI can provide structural protection against tensile in plane radial stress caused by thermal cooling after chip mass reflow. For ELK delamination, the ELK peel stress is correlated with experimental data. The simulation shows PI opening (PIO) has a big impact on the ELK peel stress. It has been found PIO plays a different role in ELK peel stress due to in plane shear deformation and out of plane thermal expansion. When stress is induced due to in plane shear deformation, smaller PIO and stiffer PI can provide better stress buffer on ELK layers. Larger PIO and stiffer PI can help to reduce the ELK peel stress induced by out of plane deformation. This study presents two failure stress metrics from fracture mechanics perspective and further understand the role of PI in flip chip Cu pillar packages.", "author_names": [ "Weiqi Wang", "Dingyou Zhang", "YangYang Sun", "David F Rae", "Lily Zhao", "Jiantao Zheng", "Mark Andre Schwarz", "Milind Shah", "Ahmer Syed" ], "corpus_id": 51981779, "doc_id": "51981779", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Study of Polyimide in Chip Package Interaction for Flip Chip Cu Pillar Packages", "venue": "2018 IEEE 68th Electronic Components and Technology Conference (ECTC)", "year": 2018 }, { "abstract": "In order to address the Chip Package Interaction (CPI) risks associated with advanced silicon packaging, GLOBALFOUNDRIES has developed Finite Element (FE) models to simulate the mechanical stress in the Backend of Line (BEoL) and Far Back End of Line (FBEoL) during the flip chip assembly process and multiple reflow (MR) cycling test. This paper discusses the complexity involved in the CPI mechanical performance and use of various modeling methods to assess and mitigate the CPI failure risk. The paper also highlights the quantitative package model validation against experimental data based on newly developed Cohesive Zone Material (CZM) modeling methodology.", "author_names": [ "Kashi Vishwanath Machani", "Frank Kuechenmeister", "Dirk Breuer", "Jens Paul" ], "corpus_id": 220939730, "doc_id": "220939730", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Chip Package Interaction (CPI) Stress Modeling", "venue": "2020 21st International Conference on Thermal, Mechanical and Multi Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)", "year": 2020 }, { "abstract": "Abstract This paper describes major contributing factors to the CPI risk and reveals the mitigation strategy successfully applied jointly by GLOBALFOUNDRIES as the silicon supplier and Qualcomm Technologies, Inc. as the customer responsible for packaging. This strategy involves thermo mechanical modelling, data collection on wafer level using shear test to assess the BEoL stability, Cu Pillar process development and optimization. The qualification of these process changes had been completed and implemented in volume production. The paper also discusses mechanical wafer level and thermo mechanical package modeling approaches. A model has been applied to determine the critical factors on BEoL stress/strain during the flip chip assembly reflow process. These factors include for instance the Cu Pillar bump geometry and stack up. The results of the modelling work were used to set up experiments to further mitigate CPI related failure modes in BEoL on the package level. GLOBALFOUNDRIES and Qualcomm Technologie.", "author_names": [ "Frank Kuechenmeister", "Dirk Breuer", "Holm Geisler", "Bjoern Boehme", "Kashi Vishwanath Machani", "Michael Hecker", "Sven Kosgalwies", "Jae Kyu Cho", "Dongming He", "Xuefeng Zhang", "Lily Zhao" ], "corpus_id": 86579177, "doc_id": "86579177", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Chip Package Interaction: Understanding of Contributing Factors in Back End of Line (BEoL) Silicon, Cu Pillar Design and Applied Process Improvements", "venue": "", "year": 2018 }, { "abstract": "In this work CPI induced mechanical stress for 3D stacks and 3D interposer packages is studied. The stress built during package assembly has been obtained using finite element modeling (FEM) For the package layout and materials properties chosen for this work, the results shown that the stresses induced during the processing of a 3D stacks and 3D interposer configuration are similar when they are assembled in a Flip Chip Ball Grid Array (fcBGA) package. Furthermore, the interconnection between the different silicon dies assured with the use of mbumps were analyzed with different interconnect densities and configurations. Results shown that stress induced around the mbumps increases by increasing the mbump pitch. Different molding configurations for the fcBGA packages were investigated, including high power (exposed die) and low power (embedded dies) packages. The results showed that exposed die packages present lower out of plane deformation due to a reduction of the epoxy mold compound (EMC) thickness. It is very important to accurately calculate the residual stresses that each processing steps of the assembly induced on the die. Mass reflow and thermo compression bonding process assembly have been investigated. Results showed that solder joint reflow is the bottleneck for mass reflow process assembly, high stress in this step indicate that failures can occur. In this work we showed that low CTE laminate is a good alternative to reduce until 60% stress at flip chip reflow step.", "author_names": [ "Melina Lofrano", "Mario Gonzalez", "Wei Tong Guo", "Geert Van der Plas" ], "corpus_id": 17002157, "doc_id": "17002157", "n_citations": 7, "n_key_citations": 1, "score": 0, "title": "Chip package interaction: A stress analysis on 3D IC's packages", "venue": "2015 16th International Conference on Thermal, Mechanical and Multi Physics Simulation and Experiments in Microelectronics and Microsystems", "year": 2015 } ]

[ { "abstract": "The most important impact of power electronics on our society in the last 50 years has been the elimination of the 60 Hz ac power delivery system for consumer electronic products. Central to this achievement is the use of silicon (Si) power devices and pulsewidth modulation (PWM) techniques in delivering regulated ac and dc powers to low voltage (LV) loads such as light emitting diodes and computers. These solid state power electronic converters have provided our society numerous benefits, including high quality power and substantial energy savings. They also form the core technology for integrating renewable energies such as wind and solar into our power grid. Figure 1 shows a typical power delivery architecture commonly found in computer supplies and data centers. The incoming universal ac grid power is converted by a power factor correction circuit to 400 V dc before it is stepped down to a lower voltage dc intermediate bus, such as 12 V, and then it powers the digital loads at voltages as low as 1 V by a point of load converter. Si power metal oxide semiconductor field effective transistor (MOSFET) transistors from 20 V to 700 V are almost exclusively used in this application with switching frequencies from tens of kilohertz to one megahertz. Emerging devices based on gallium nitride (GaN) heterojunction field effect transistors reduce the switching and conduction losses when compared with Si power MOSFETs and are, therefore, poised to compete in these applications, driven by the need for higher energy efficiency and higher power density.", "author_names": [ "Alex Q Huang" ], "corpus_id": 20478534, "doc_id": "20478534", "n_citations": 125, "n_key_citations": 4, "score": 1, "title": "Medium Voltage Solid State Transformer: Technology for a Smarter and Resilient Grid", "venue": "IEEE Industrial Electronics Magazine", "year": 2016 }, { "abstract": "As an eventual replacement of the century old line frequency transformer (LFT) the Solid State Transformer (SST) has been investigated intensively in the past decade due to its ability to offer many smart functionalities such as voltage regulation and power flow control in the distribution power grid. For the medium voltage and high voltage SSTs, the availability and cost of high voltage power devices are the major limitations. One possible solution is to use modular SST architecture in an Input Series Output Parallel (ISOP) configuration to reach high input voltage and high power capacity. However, modular SST introduces additional challenges in control due to the need for many voltage and current sensors, multiple control loops to achieve cell to cell level voltage and power balancing. To address these problems, this paper introduces a novel modular SST solution utilizing single stage AC AC resonant converter as the modular cell with distributed open loop control. The proposed modular SST is therefore capable of reaching medium and high voltages easily with simple and robust control. The proposed architecture eliminates the DC DC stage hence the associated bulky DC link capacitors. Higher power density can therefore be achieved. 10 kW modular LLC converter prototype is developed based on 1.2kV SiC MOSFETs. Peak AC AC efficiency up to 97.3% is achieved and demonstrated. Voltage and power balancing among modular cells are analyzed against cell to cell variations, including resonant frequency, switching frequency and losses. Simulation results show that the proposed modular SST has no performance degradation even considering those variations in a practical system. An ISOP architecture using two LLC converters is also demonstrated with preliminary experimental results, showing that with LLC converters working close to resonant frequency, the input voltage balancing can be achieved.", "author_names": [ "Xin Zhao", "Yang Lei", "Haoming Wang", "Xiangjun Quan", "Alex Q Huang" ], "corpus_id": 208632142, "doc_id": "208632142", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Design of A Medium Voltage Solid State Transformer based on Modular AC AC Resonant Converter and an Input Series Output Parallel Architecture", "venue": "2019 IEEE Energy Conversion Congress and Exposition (ECCE)", "year": 2019 }, { "abstract": "Due to much higher achievable blocking voltage and faster switching speed, power devices based on wide bandgap (WBG) silicon carbide (SiC) material are ideal for medium voltage (MV) power electronics applications. For example, a 15 kV SiC MOSFET allows a simple and efficient two level converter configuration for a 7.2 kV solid state transformer (SST) for smart grid applications. Compared with multilevel input series and output parallel (ISOP) solution, this approach offers higher efficiency and reliability, reduced system weight and cost by operating at medium to high switching frequency. However, the main concern is how to precisely implement this device in different MV applications, achieving highest switching frequency while maintaining good thermal performance. This paper reviews the characteristics of 15 kV SiC MOSFET and offers a comprehensive guideline of implementing this device in practical MV power conversion scenarios such as AC DC, DC DC and AC AC in terms of topology selection, loss optimization and thermal management.", "author_names": [ "Alex Q Huang", "Qianlai Zhu", "Li Wang", "Liqi Zhang" ], "corpus_id": 56403837, "doc_id": "56403837", "n_citations": 76, "n_key_citations": 2, "score": 0, "title": "15 kV SiC MOSFET: An enabling technology for medium voltage solid state transformers", "venue": "", "year": 2017 }, { "abstract": "Solid state transformers (SSTs) are evolved as an emerging technology which offer several key features in integrating different grids, storage devices, and renewable energy sources, etc. In this paper, a 10 kV SiC MOSFET enabled Mobile Utility Support Equipment based SST (MUSE SST) is presented for integrating a medium voltage (MV) AC grid (4.16 kV L L, 60 Hz) and a low voltage (LV) AC grid (480 V L L, 60 Hz) The MUSE SST consist of three power conversion stages: MV side active front end converter (AFEC: MV) dual active bridge (DAB) and LV side active front end converter (AFEC: LV) In order to protect MUSE SST from various abnormal operating conditions, different protection schemes are discussed. Dedicated gate drivers incorporating device short circuit protection are implemented for both the MV and the LV SiC MOSFETs. It is observed that the MV short circuit faults are found to be severe and resulting in very high inrush currents from the MV grid which can lead to the impairment of entire SST system. A bi directional switch in parallel with a high impedance resistor (BSPHR) circuit based protection scheme is presented to limit the grid currents during MV dc link short circuit conditions. The BSPHR scheme and efficacy of gate drivers are validated through simulations and experimental results, respectively. The avalanche ruggedness of 10kV, SiC MOSFETs is established experimentally using a single shot unclamped inductive switching (UIS) test and the critical avalanche energy for the MOSFET failure is obtained.", "author_names": [ "Venkat N Jakka", "Sayan Acharya", "Anup Anurag", "Yos Prabowo", "Ashish Kumar", "Sanket Parashar", "Subhashish Bhattacharya" ], "corpus_id": 57364064, "doc_id": "57364064", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Protection Design Considerations of a 10 kV SiC MOSFET Enabled Mobile Utilities Support Equipment Based Solid State Transformer (MUSE SST)", "venue": "IECON 2018 44th Annual Conference of the IEEE Industrial Electronics Society", "year": 2018 }, { "abstract": "The solid state transformer (SST) is a promising technology in the future smart grid. Compared to the line frequency transformer, the SST has more control flexibilities and the plug and play ability, which allow it to interconnect a hybrid ac dc multiterminal grid for reliable and flexible power distribution. The dc bus voltage stability of an SST enabled hybrid ac dc multiterminal grid is a critical issue due to the dynamic interactions of power converters, which has been investigated in this article. The output impedance modeling method of the dual active bridge (DAB) dc/dc converters considering both the control schemes and bidirectional power flow effect is proposed. Depending on the control strategy and power flow direction, the DAB converters have three different output impedance characteristics at the low frequency range, which are capacitive, inductive, and resistive. It is found that the dynamic interaction between the inductive impedance and the capacitive impedance of DAB converters could cause instability issues when the system damping ratio is low. A hardware in the loop based impedance measurement testbed is used to extract the DAB converters' output impedance, which validates the theoretical derivation. The real time simulation results are also provided to demonstrate the dc bus voltage instability.", "author_names": [ "Qing Ye", "Ran Mo", "Haoyu Li" ], "corpus_id": 203118677, "doc_id": "203118677", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Impedance Modeling and DC Bus Voltage Stability Assessment of a Solid State Transformer Enabled Hybrid AC DC Grid Considering Bidirectional Power Flow", "venue": "IEEE Transactions on Industrial Electronics", "year": 2020 }, { "abstract": "Solid State Transformers (SST) are attracting considerable attention due to their great application potential in future smart grids. It is an essential technology capable of promoting the modernization of the electric power distribution system and it is considered a key element for interfacing future microgrid systems to medium voltage utility grids, allowing plug and play integration with multiple renewable energy sources, storage devices and DC power systems. Its main advantages in relation to conventional transformers are substantial reduction of volume and weight, fault isolation capability, voltage regulation, harmonic filtering, reactive power compensation and power factor correction. A three stage modular cascaded topology has been considered as an adequate candidate for the SST implementation, consisting of multiple power modules with input series and output parallel connection. The modular structure presents many advantages, e.g. redundancy, flexibility, lower current harmonic content and voltage stress on the power switches, however component tolerances and mismatches between modules can lead to DC link voltage imbalance and unequal power sharing that can damage the solid state transformer. This paper proposes a decentralized strategy based on adaptive droop control capable of promoting voltage and power balance among modules of a modular cascaded SST, without relying on a communication network. The behavior of the proposed strategy is assessed through a MATLAB/Simulink simulation model of an 100 kVA SST and shows that power and voltage balance are attained through inner power distribution of the SST modules, being transparent to elements connected to the transformer input and output ports. Besides that, real time simulation results are presented to validate the proposed control strategies. The performance of embedded algorithms is evaluated by the implementation of the SST in a real time simulation hardware, using a Digital Signal Processor (DSP) and high level programming.", "author_names": [ "W A Rodrigues", "Thiago Ribeiro Oliveira", "Lenin Martins Ferreira Morais", "Arthur Hermano Rezende Rosa" ], "corpus_id": 117389667, "doc_id": "117389667", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Voltage and Power Balance Strategy without Communication for a Modular Solid State Transformer Based on Adaptive Droop Control", "venue": "", "year": 2018 }, { "abstract": "In today circumstances, due to the rapid development of smart grid network the occurrence of fault become high. The levels of fault current in many places have often exceeded the withstand capacity of existing power system equipment. As a result, security, stability and reliability of power system will be negatively affected. Thus, limiting the fault current of the power system to a safe level can greatly reduce the risk of failure to the power system equipment due to high fault current flowing through the system. Because of that, there is no surprise to fault current limiting technology has become a hot spot of fault protection research since this technology can limit the fault current to a low level. In power system design view, limiting the fault current to a low level can reduce the design capacity of some electrical equipment in the power system. This will lead to the reduction to the investment cost for high capacity circuit breakers and construction of new transmission line. Consequently, from both technical and economical points of view, fault current limiting technology for reducing short circuit current is needed.", "author_names": [], "corpus_id": 209441804, "doc_id": "209441804", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Solid State Fault Current Limiters (SSFCL) in Medium Voltage Systems", "venue": "", "year": 2019 }, { "abstract": "The rapid evolution of power electronic solutions in all around the globe brings a common problem, which is the adoption of nonlinear loads. This fact carries out a strong impact over the quality of power systems and consequently on energy efficiency, since nonlinear loads act as sources of harmonic currents that flow to other loads or even sources, causing non optimal performance in their operation. Nowadays, conventional transformers are limited to just manage (increase or decrease) voltage level, but they are not able to deal with power quality events, such as harmonics, sag, swell, among others. Hence, there is a need to incorporate a versatile smart device to deal with the challenges previously described for a smart grid environment. This chapter introduces a solid state transformer (SST) with topology of multilevel cascade H bridge converter as a solution. SST is an emerging technology that has the advantages of low volume, low weight, fault isolation, and other management features. Within its fundamental operation, this chapter presents a detailed description of a SST system comprising communication and control, highlighting their main advantages in comparison with conventional transformer such as mitigation of waveform harmonic distortion, allowance of integration of distributed generation, and bi directional power flow.", "author_names": [ "Fernando Vaca-Urbano", "Manuel S Alvarez-Alvarado", "Angel A Recalde", "Felix Moncayo-Rea" ], "corpus_id": 140051346, "doc_id": "140051346", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Solid State Transformer for Energy Efficiency Enhancement", "venue": "", "year": 2019 }, { "abstract": "Large scale grid connected photovoltaic energy generation systems are progressing remarkably benefiting from the latest developments in solid state semiconductors technology. In such systems, the photovoltaic arrays can be connected directly to the medium voltage grid without employing a bulky line frequency transformer to step up the voltage. Nano crystalline cores with a small size and a high permeability operating at medium or high frequency can be installed in the power conversion stage. Hence, the necessary isolation as well as voltage boosting features can be provided. However, only a few power converters allow this type of isolation. This paper proposes a new modular converter structure suitable for medium voltage grid connected systems with high frequency isolation. The output voltages of the series connected modules are added in order to provide the necessary voltage boosting. Four different power converter topologies with small input capacitors can be used as submodules for the presented medium voltage configuration having different advantages and drawbacks. These different topologies are analyzed in terms of power losses, footprint, and functionality. To validate the mathematical analysis and the computer simulations, a scaled down 5 kVA three phase, 1 kV prototype is built and tested with four modules for each phase.", "author_names": [ "Ahmed Darwish", "Mohamed A Elgenedy" ], "corpus_id": 53710152, "doc_id": "53710152", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Current Source Modular Medium Voltage Grid Connected System With High Frequency Isolation for Photovoltaic Applications", "venue": "IEEE Transactions on Energy Conversion", "year": 2019 }, { "abstract": "The solid state transformer (SST) was conceived as a replacement for the conventional power transformer, with both lower volume and weight. The smart transformer (ST) is an SST that provides ancillary services to the distribution and transmission grids to optimize their performance. Hence, the focus shifts from hardware advantages to functionalities. One of the most desired functionalities is the dc connectivity to enable a hybrid distribution system. For this reason, the ST architecture shall be composed of at least two power stages. The standard design procedure for this kind of system is to design each power stage for the maximum load. However, this design approach might limit additional services, like the reactive power compensation on the medium voltage (MV) side, and it does not consider the load regulation capability of the ST on the low voltage (LV) side. If the SST is tailored to the services that it shall provide, different stages will have different designs, so that the ST is no longer a mere application of the SST but an entirely new subject.", "author_names": [ "Levy Ferreira Costa", "Giovanni De Carne", "Giampaolo Buticchi", "Marco Liserre" ], "corpus_id": 27604499, "doc_id": "27604499", "n_citations": 118, "n_key_citations": 6, "score": 0, "title": "The Smart Transformer: A solid state transformer tailored to provide ancillary services to the distribution grid", "venue": "IEEE Power Electronics Magazine", "year": 2017 } ]

[ { "abstract": "Heralded entangling quantum gates are an essential element for the implementation of large scale optical quantum computation. Yet, the experimental demonstration of genuine heralded entangling gates with free flying output photons in linear optical system, was hindered by the intrinsically probabilistic source and double pair emission in parametric down conversion. Here, by using an on demand single photon source based on a semiconductor quantum dot embedded in a micropillar cavity, we demonstrate a heralded controlled NOT (CNOT) operation between two single photons for the first time. To characterize the performance of the CNOT gate, we estimate its average quantum gate fidelity of (87.8+ 1.2) As an application, we generated event ready Bell states with a fidelity of (83.4+ 2.4) Our results are an important step towards the development of photon photon quantum logic gates.", "author_names": [ "Jin-Peng Li", "Xuemei Gu", "Jian Qin", "Dian Wu", "Xiang You", "Hui Wang", "Christian Schneider", "Sven Hofling", "Yongheng Huo", "Chao-Yang Lu", "Nai-Le Liu", "Li Li", "Jian-Wei Pan" ], "corpus_id": 225094250, "doc_id": "225094250", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Heralded Nondestructive Quantum Entangling Gate with Single Photon Sources.", "venue": "Physical review letters", "year": 2021 }, { "abstract": "We theoretically and experimentally investigate the conditions necessary to realize highly indistinguishable single photon sources using parametric down conversion. The visibilities of Hong Ou Mandel (HOM) interference between photons in different fluorescence pairs were measured and a visibility of 95.8 2% was observed using a 0.7 mm long beta barium borate crystal and 2 nm bandpass filters, after compensating for the reflectivity of the beam splitter. A theoretical model of HOM interference visibilities is proposed that considers non uniform down conversion process inside the nonlinear crystal. It well explains the experimental results. (c) 2012 Optical Society of America OCIS codes: (270.5585) Quantum information and processing; (270.5290) Photon statistics. References and links 1. C. H. Bennett and G. Brassard, \"Quantum cryptography: public key distribution and coin tossing,\" Proceedings of IEEE International Conference on Computers Systems and Signal Processing 175 179 (1984) 2. M. A. Nielsen and I. L. Chuang, Quantum Computation and Quantum Information, (Cambridge University Press, Cambridge, England, 2000) 3. V. Giovannetti, S. Lloyd, and L. Maccone, \"Quantum enhanced measurements: beating the standard quantum limit,\" Science 306, 1330 1336 (2004) 4. E. Knill, R. Laflamme, and G. J. Milburn, \"A scheme for efficient quantum computation with linear optics,\" Nature (London) 409, 46 52 (2001) 5. C. K. Hong, Z. Y. Ou, and L. Mandel, \"Measurement of subpicosecond time intervals between two photons by interference,\" Phys. Rev. Lett. 59, 2044 2046 (1987) 6. T. C. Ralph, N. K. Langford, T. B. Bell, and A. G. White, \"Linear optical controlled NOT gate in the coincidence basis,\" Phys. Rev. A 65, 062324 (2002) 7. H. F. Hofmann and S. Takeuchi, \"Quantum phase gate for photonic qubits using only beam splitters and postselection,\" Phys. Rev. A 66, 024308 (2002) 8. J. L. O'Brien, G. J. Pryde, A. G. White, T. C. Ralph, and D. Branning, \"Demonstration of an all optical quantum controlled NOT gate,\" Nature (London) 426, 264 267 (2003) 9. N. K. Langford, T. J. Weinhold, R. Prevedel, K. J. Resch, A. Gilchrist, J. L. O'Brien, G. J. Pryde, and A. G. White, \"Demonstration of a simple entangling optical gate and its use in Bell state analysis,\" Phys. Rev. Lett. 95, 210504 (2005) 10. N. Kiesel, C. Schmid, U. Weber, R. Ursin, and H. Weinfurter, \"Linear optics controlled phase gate made simple,\" Phys. Rev. Lett. 95, 210505 (2005) 11. R. Okamoto, H. F. Hofmann, S. Takeuchi, and K. Sasaki, \"Demonstration of an optical quantum controlled NOT gate without path interference,\" Phys. Rev. Lett. 95, 210506 (2005) 12. R. Okamoto, J. L. O'Brien, H. F. Hoffman, T. Nagata, K. Sasaki, and S. Takeuchi, \"An entanglement filter,\" Science 323, 483 485 (2009) 13. B. P. Lanyon, M. Barbieri, M. P. Almeida, T. Jennewein, T. C. Ralph, K. J. Resch, G. J. Pryde, J. L. O'Brien, A. Gilchrist, and A. G. White, \"Simplifying quantum logic using higher dimensional Hilbert spaces,\" Nat. Phys. 5, 134 140 (2009) #167018 $15.00 USD Received 18 Apr 2012; revised 25 May 2012; accepted 29 May 2012; published 22 Jun 2012 (C) 2012 OSA 2 July 2012 Vol. 20, No. 14 OPTICS EXPRESS 15275 14. R. Okamoto, J. L. O'Brien, H. F. Hofmann, and S. Takeuchi, \"Realization of a Knill Laflamme Milburn C NOT gate a photonic quantum circuit combining effective optical nonlinearities,\" Proc. Natl. Acad. Sci. USA 108, 10067 10071 (2011) 15. H. Lee, P. Kok, and J. P. Dowling, \"A quantum Rosetta stone for interferometry,\" J. Mod. Opt. 49, 2325 2338 (2002) 16. T. Nagata, R. Okamoto, J. L. O'Brien, K. Sasaki, and S. Takeuchi, \"Beating the standard quantum limit with four entangled photons,\" Science 316, 726 729 (2007) 17. N. Boto, P. Kok, D. S. Abrams, S. L. Braunstein, C. P. Williams, and J. P. Dowling, \"Quantum interferometric optical lithography: exploiting entanglement to beat the diffraction limit,\" Phys. Rev. Lett. 85, 2733 2736 (2000) 18. Y. Kawabe, H. Fujiwara, R. Okamoto, K. Sasaki, and S. Takeuchi, \"Quantum interference fringes beating the diffraction limit,\" Opt. Express 15, 14244 14250 (2007) 19. T. Nagata, R. Okamoto, H. F. Hofmann, and S. Takeuchi, \"Analysis of experimental error sources in a linearoptics quantum gate,\" New J. Phys. 12, 043053 (2010) 20. T. Jennewein, R. Ursin, M. Aspelmeyer, and A. Zeilinger, \"Performing high quality multi photon experiments with parametric down conversion,\" J. Phys. B 42, 114008 (2009) 21. P. R. Tapster and J. G. Rarity, \"Photon statistics of pulsed parametric light,\" J. Mod. Opt. 45, 595 604 (1998) 22. H. R. Zhang and R. P. Wang, \"Theory of fourfold interference with photon pairs from spatially separated sources,\" Phys. Rev. A 75, 053804 (2007) 23. M. Barbieri, \"Effects of frequency correlation in linear optical entangling gates operated with independent photons,\" Phys. Rev. A 76, 043825 (2007) 24. R. Kaltenbaek, R. Prevedel, M. Aspelmeyer, and A. Zeilinger, \"High fidelity entanglement swapping with fully independent sources,\" Phys. Rev. A 79, 040302(R) (2009) 25. M. Zukowski, A. Zeilinger, and H. Weinfurter, \"Entangling independent pulsed photon sources,\" Ann. N.Y. Acad. Sci. 755, 91 102 (1995) 26. R. Kaltenbaek, B. Blauensteiner, M. Zukowski, M. Aspelmeyer, and A. Zeilinger, \"Experimental interference of independent photons,\" Phys. Rev. Lett. 96, 240502 (2006) 27. R. Kaltenbaek, 2008 PhD Thesis. 28. S. M. Saltiel, K. Koynov, B. Agate, and W. Sibbett, \"Second harmonic generation with focused beams under conditions of large group velocity mismatch,\" J. Opt. Soc. Am. B 21, 591 598 (2004) 29. Y. Kawabe, H. Fujiwara, S. Takeuchi, and K. Sasaki, \"Investigation of the spatial propagation properties of type I parametric fluorescence by use of tuning curve filtering method,\" Jpn. J. Appl. Phys. 46, 5802 5808 (2007)", "author_names": [ "Masato Tanida", "Ryo Okamoto", "Shigeki Takeuchi" ], "corpus_id": 25213912, "doc_id": "25213912", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Instructions for use Title Highly indistinguishable heralded single photon sources using parametric down conversion", "venue": "", "year": 2018 }, { "abstract": "Light states composed of multiple entangled photons such as cluster states are essential for developing and scaling up quantum computing networks. Photonic cluster states can be obtained from single photon sources and entangling gates, but so far this has only been done with probabilistic sources constrained to intrinsically low efficiencies, and an increasing hardware overhead. Here, we report the resource efficient generation of polarization encoded, individually addressable photons in linear cluster states occupying a single spatial mode. We employ a single entangling gate in a fiber loop configuration to sequentially entangle an ever growing stream of photons originating from the currently most efficient single photon source technology a semiconductor quantum dot. With this apparatus, we demonstrate the generation of linear cluster states up to four photons in a single mode fiber. The reported architecture can be programmed for linear cluster states of any number of photons, that are required for photonic one way quantum computing schemes. Generating photonic cluster states using a single non heralded source and a single entangling gate would optimise scalability and reduce resource overhead. Here, the authors generate up to 4 photon cluster states using a quantum dot coupled to a fibre loop, with a fourfold generation rate of 10 Hz.", "author_names": [ "D Istrati", "Y Pilnyak", "J C Loredo", "C Anton", "Niccolo Somaschi", "P Hilaire", "Helene Ollivier", "Martin Esmann", "Lior Cohen", "L I Vidro", "Clement Millet", "Aristide Lemaitre", "Isabelle Sagnes", "A Harouri", "Loic Lanco", "Pascale Senellart", "H S Eisenberg" ], "corpus_id": 234926552, "doc_id": "234926552", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Sequential Generation of Linear Cluster States from a Single Photon Emitter", "venue": "", "year": 2020 }, { "abstract": "Lithium niobate photonic circuits have the salutary property of permitting the generation, transmission, and processing of photons to be accommodated on a single chip. Compact photonic circuits such as these, with multiple components integrated on a single chip, are crucial for efficiently implementing quantum information processing schemes. We present a set of basic transformations that are useful for manipulating modal qubits in Ti:LiNbO3 photonic quantum circuits. These include the mode analyzer, a device that separates the even and odd components of a state into two separate spatial paths; the mode rotator, which rotates the state by an angle in mode space; and modal Pauli spin operators that effect related operations. We also describe the design of a deterministic, two qubit, single photon, CNOT gate, a key element in certain sets of universal quantum logic gates. It is implemented as a Ti:LiNbO3 photonic quantum circuit in which the polarization and mode number of a single photon serve as the control and target qubits, respectively. It is shown that the effects of dispersion in the CNOT circuit can be mitigated by augmenting it with an additional path. The performance of all of these components are confirmed by numerical simulations. The implementation of these transformations relies on selective and controllable power coupling among singleand two mode waveguides, as well as the polarization sensitivity of the Pockels coefficients in LiNbO3. (c) 2010 Optical Society of America OCIS codes: (270.5585) Quantum information and processing; (230.7380) Waveguides, channeled; (130.3730) Lithium niobate. References and links 1. M. F. Saleh, B. E. A. Saleh, and M. C. Teich, \"Modal, spectral, and polarization entanglement in guided wave parametric down conversion,\" Phys. Rev. A 79, 053 842 (2009) 2. M. F. Saleh, G. Di Giuseppe, B. E. A. Saleh, and M. C. Teich, \"Photonic circuits for generating modal, spectral, and polarization entanglement,\" IEEE Photon. J. 2, 736 752 (2010) 3. M. Fiorentino, S. M. Spillane, R. G. Beausoleil, T. D. Roberts, P. Battle, and M. W. Munro, \"Spontaneous parametric down conversion in periodically poled KTP waveguides and bulk crystals,\" Opt. Express 15, 7479 7488 (2007) #131866 $15.00 USD Received 19 Jul 2010; revised 3 Sep 2010; accepted 3 Sep 2010; published 10 Sep 2010 (C) 2010 OSA 13 September 2010 Vol. 18, No. 19 OPTICS EXPRESS 20475 4. M. Avenhaus, M. V. Chekhova, L. A. Krivitsky, G. Leuchs, and C. Silberhorn, \"Experimental verification of high spectral entanglement for pulsed waveguided spontaneous parametric down conversion,\" Phys. Rev. A 79, 043 836 (2009) 5. P. J. Mosley, A. Christ, A. Eckstein, and C. Silberhorn, \"Direct measurement of the spatial spectral structure of waveguided parametric down conversion,\" Phys. Rev. Lett. 103, 233 901 (2009) 6. T. Zhong, F. N. Wong, T. D. Roberts, and P. Battle, \"High performance photon pair source based on a fiber coupled periodically poled KTiOPO4 waveguide,\" Opt. Express 17, 12 019 12 030 (2009) 7. J. Chen, A. J. Pearlman, A. Ling, J. Fan, and A. Migdall, \"A versatile waveguide source of photon pairs for chip scale quantum information processing,\" Opt. Express 17, 6 727 6 740 (2009) 8. A. Politi, M. J. Cryan, J. G. Rarity, S. Yu, and J. L. O'Brien, \"Silica on silicon waveguide quantum circuits,\" Science 320, 646 649 (2008) 9. J. C. F. Matthews, A. Politi, A. Stefanov, and J. L. O'Brien, \"Manipulation of multiphoton entanglement in waveguide quantum circuits,\" Nature Photon. 3, 346 350 (2009) 10. C. H. Bennett and P. W. Shor, \"Quantum information theory,\" IEEE Trans. Inform. Theory 44, 2724 2742 (1998) 11. M. A. Nielsen and I. L. Chuang, Quantum Computation and Quantum Information (Cambridge University Press, Cambridge, UK, 2000) 12. J. L. O'Brien, A. Furusawa, and J. Vuckovic, \"Photonic quantum technologies,\" Nature Photon. 3, 687 695 (2009) 13. A. Politi, J. C. F. Matthews, M. G. Thompson, and J. L. O'Brien, \"Integrated quantum photonics,\" IEEE J. Sel. Topics Quantum Electron. 15, 1673 1684 (2009) 14. G. Cincotti, \"Prospects on planar quantum computing,\" J. Lightwave Technol. 27, 5755 5766 (2009) 15. T. D. Ladd, F. Jelezko, R. Laflamme, Y. Nakamura, C. Monroe, and J. L. O'Brien, \"Quantum computers,\" Nature 464, 45 53 (2010) 16. H. Nishihara, M. Haruna, and T. Suhara, Optical Integrated Circuits (McGraw Hill, New York, 1989) 17. B. E. A. Saleh and M. C. Teich, Fundamentals of Photonics, 2nd ed. (Wiley, Hoboken, NJ, 2007) 18. A. C. Busacca, C. L. Sones, R. W. Eason, and S. Mailis, \"First order quasi phase matched blue light generation in surface poled Ti:indiffused lithium niobate waveguides,\" Appl. Phys. Lett. 84, 4430 4432 (2004) 19. Y. L. Lee, C. Jung, Y. C. Noh, M. Park, C. Byeon, D. K. Ko, and J. Lee, \"Channel selective wavelength conversion and tuning in periodically poled Ti:LiNbO3 waveguides,\" Opt. Express 12, 2649 2655 (2004) 20. S. Tanzilli, H. De Riedmatten, W. Tittel, H. Zbinden, P. Baldi, M. De Micheli, D. B. Ostrowsky, and N. Gisin, \"Highly efficient photon pair source using periodically poled lithium niobate waveguide,\" Electron. Lett. 37, 26 28 (2001) 21. H. Guillet de Chatellus, A. V. Sergienko, B. E. A. Saleh, M. C. Teich, and G. Di Giuseppe, \"Non collinear and non degenerate polarization entangled photon generation via concurrent type I parametric downconversion in PPLN,\" Opt. Express 14, 10 060 10 072 (2006) 22. R. C. Alferness and R. V. Schmidt, \"Tunable optical waveguide directional coupler filter,\" Appl. Phys. Lett. 33, 161 163 (1978) 23. R. C. Alferness, \"Efficient waveguide electro optic TE TM mode converter/wavelength filter,\" Appl. Phys. Lett. 36, 513 515 (1980) 24. J. Hukriede, D. Runde, and D. Kip, \"Fabrication and application of holographic Bragg gratings in lithium niobate channel waveguides,\" J. Phys. D: Appl. Phys. 36, R1 R16 (2003) 25. D. Runde, S. Brunken, S. Breuer, and D. Kip, \"Integrated optical add/drop multiplexer for DWDM in lithium niobate,\" Appl. Phys. B: Lasers Opt. 88, 83 88 (2007) 26. D. Runde, S. Breuer, and D. Kip, \"Mode selective coupler for wavelength multiplexing using LiNbO3:Ti optical waveguides,\" Cent. Eur. J. Phys. 6, 588 592 (2008) 27. R. V. Schmidt and H. Kogelnik, \"Electro optically switched coupler with stepped Db reversal using Ti diffused LiNbO3 waveguides,\" Appl. Phys. Lett. 28, 503 506 (1976) 28. H. Kogelnik and R. V. Schmidt, \"Switched directional couplers with alternating Db \" IEEE J. Quantum Electron. QE 12, 396 401 (1976) 29. D. P. DiVincenzo, \"Two bit gates are universal for quantum computation,\" Phys. Rev. A 51, 1015 1022 (1995) 30. E. Knill, R. Laflamme, and G. J. Milburn, \"A scheme for efficient quantum computation with linear optics,\" Nature 409, 46 52 (2001) 31. M. Fiorentino and F. N. C. Wong, \"Deterministic controlled NOT gate for single photon two qubit quantum logic,\" Phys. Rev. Lett. 93, 070 502 (2004) 32. N. Gisin, S. Pironio, and N. Sangouard, \"Proposal for implementing device independent quantum key distribution based on a heralded qubit amplifier,\" Phys. Rev. Lett. 105, 070 501 (2010) 33. S. Glancy, H. M. Vasconcelos, and T. C. Ralph, \"Transmission of optical coherent state qubits,\" Phys. Rev. A 70, 022 317 (2004) 34. D. H. Jundt, \"Temperature dependent Sellmeier equation for the index of refraction, ne, in congruent lithium niobate,\" Opt. Lett. 22, 1553 1555 (1997) 35. K. K. Wong, ed. Properties of Lithium Niobate (Institution of Electrical Engineers, Stevenage, U.K. 2002) 36. M. D. Feit, J. A. Fleck, Jr. and L. McCaughan, \"Comparison of calculated and measured performance of diffused #131866 $15.00 USD Received 19 Jul 2010; revised 3 Sep 2010; accepted 3 Sep 2010; published 10 Sep 2010 (C) 2010 OSA 13 September 2010 Vol. 18, No. 19 OPTICS EXPRESS 20476 channel waveguide couplers,\" J. Opt. Soc. Am. 73, 1296 1304 (1983) 37. S. K. Korotky and R. C. Alferness, \"Ti:LiNbO3 integrated optic technology,\" in Integrated Optical Circuits and Components: Design and Applications, L. D. Hutcheson, ed. (Marcel Dekker, New York, 1987) 38. G. B. Hocker and W. K. Burns, \"Mode dispersion in diffused channel waveguides by the effective index method,\" Appl. Opt. 16, 113 118 (1977) 39. C. H. Bennett and G. Brassard, \"Quantum cryptography: Public key distribution and coin tossing,\" in Proceedings of the International Conference on Computers, Systems Signal Processing, pp. 175 179 (Institute of Electrical and Electronics Engineers, Bangalore, India, 1984) 40. A. F. Abouraddy, T. Yarnall, B. E. A. Saleh, and M. C. Teich, \"Violation of Bell's inequality with continuous spatial variables,\" Phys. Rev. A 75, 052 114 (2007) 41. T. Yarnall, A. F. Abouraddy, B. E. A. Saleh, and M. C. Teich, \"Synthesis and analysis of entangled photonic qubits in spatial parity space,\" Phys. Rev. Lett. 99, 250 502 (2007) 42. T. Yarnall, A. F. Abouraddy, B. E. A. Saleh, and M. C. Teich, \"Experimental violation of Bell's inequality in spatial parity space,\" Phys. Rev. Lett. 99, 170 408 (2007) 43. B. E. A. Saleh and M. C. Teich, \"Sub Poisson light generation by selective deletion from cascaded atomic emissions,\" Optics Commun. 52, 429 432 (1985) 44. N. Gisin, G. Ribordy, W. Tittel, and H. Zbinden, \"Quantum Cryptography,\" Rev. Mod. Phys. 74, 145 195 (2002) 45. A. F. Abouraddy, B. E. A. Saleh, A. V. Sergienko, and M. C. Teich, \"Degree of entanglement for two qubits,\" Phys. Rev. A 64, 050 101 (2001) 46. P. J. Mosley, J. S. Lundeen, B. J. Smith, P. Wasylczyk, A. B. U'Ren, C. Silberhorn, and I. A. Walmsley, \"Heralded generation of ultrafast single photons in pure quantum states,\" Phys. Rev. Lett. 100, 133 601 (2008) 47. Z. H. Levine, J. Fan, J. Chen, A. Ling, and A. Migdall, \"Heralded, pure state single photon source based on a Potassium Titanyl Phosphate waveguide,\" Opt. Express 18, 3708 3718 (2010) 48. W. P. Grice, A. B. U'Ren, and I. A. Walmsley, \"Eliminating frequency and space time correlations in multiphoton states,\" Phys. Rev. A 64, 063 815 (200", "author_names": [ "Mohammed F Saleh", "Giovanni Di Giuseppe", "Bahaa E A Saleh", "Malvin Carl Teich" ], "corpus_id": 201687072, "doc_id": "201687072", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Modal and polarization qubits in Ti LiNbO 3 photonic circuits for a universal quantum logic gate 1 1 2010", "venue": "", "year": 2019 }, { "abstract": "The desire to understand the interaction between light and matter has stimulated centuries of research, leading to technological achievements that have shaped our world. One contemporary frontier of research into light matter interaction considers regimes where quantum effects dominate. By understanding and manipulating these quantum effects, a vast array of new quantum enhanced technologies become accessible. In this thesis, I explore and analyze fundamental components and processes for quantum optical devices with a focus on solid state quantum systems. This includes indistinguishable single photon sources, deterministic sources of entangled photonic states, photon heralded entanglement generation between remote quantum systems, and deterministic optically mediated entangling gates between local quantum systems. For this analysis, I make heavy use of an analytic quantum trajectories approach applied to a general Markovian master equation of an optically active quantum system, which I introduce as a photon number decomposition. This approach allows for many realistic system imperfections, such as emitter pure dephasing, spin decoherence, and measurement imperfections, to be taken into account in a straightforward and comprehensive way.", "author_names": [ "Stephen C Wein" ], "corpus_id": 234680966, "doc_id": "234680966", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Modelling Markovian light matter interactions for quantum optical devices in the solid state", "venue": "", "year": 2021 }, { "abstract": "We experimentally demonstrate a source of nearly pure single photons in arbitrary temporal shapes heralded from a parametric down conversion (PDC) source at telecom wavelengths. The technology is enabled by the tailored dispersion of in house fabricated waveguides with shaped pump pulses to directly generate the PDC photons in on demand temporal shapes. We generate PDC photons in Hermite Gauss and frequency binned modes and confirm a minimum purity of 0.81, even for complex temporal shapes. (c) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement OCIS codes: (270.0270) Quantum optics; (320.7110) Ultrafast nonlinear optics; (320.5540) Pulse shaping. References and links 1. A. N Boto, P. Kok, D. S. Abrams, S. L. Braunstein, C. P. Williams, and J. P. Dowling, \"Quantum interferometric optical lithography: exploiting entanglement to beat the diffraction limit,\" Phys. Rev. Lett. 85(13) 2733 (2000) 2. N. Treps, U. Andersen, B. Buchler, P. K. Lam, A. Maitre, H. A. Bachor, and C. Fabr, \"Surpassing the standard quantum limit for optical imaging using nonclassical multimode light,\" Phys. Rev. Lett. 88(20) 203601 (2002) 3. N. C. Menicucci, S. T. Flammia, and O. Pfister, \"One way quantum computing in the optical frequency comb,\" Phys. Rev. Lett. 101(13) 130501 (2008) 4. S. Rahimi Keshari, T. C. Ralph, and C. M Caves, \"Sufficient conditions for efficient classical simulation of quantum optics,\" Phys. Rev. X 6(2) 021039 (2016) 5. T. Jennewein, C. Simon, G. Weihs, H. Weinfurter, and A. Zeilinger, \"Quantum cryptography with entangled photons,\" Phys. Rev. Lett. 84(20) 4729 4732 (2000) 6. J. Nunn, L.J. Wright, C. Soller, L. Zhang, I.A. Walmsley, and B.J. Smith, \"Large alphabet time frequency entangled quantum key distribution by means of time to frequency conversion,\" Opt. Express 21(13) 15959 15973 (2013) 7. T. Zhong, H. Zhou, R. D Horansky, C. Lee, V. B. Verma, A. E. Lita, A. Restelli, J. C. Bienfang, R. P. Mirin, T. Gerrits, S. W. Nam, F. Marsili, M. D. Shaw, Z. Zhang, L. Wang, D. Englund, G. W. Wornell, J. H. Shapiro, and F. N. C. Wong, \"Photon efficient quantum key distribution using time energy entanglement with high dimensional encoding,\" New J. Phys. 17(2) 022002 (2015) 8. P. J Mosley, J. Lundeen, B. Smith, P. Wasylczyk, A. B. U'Ren, C. Silberhorn, and I. A. Walmsley, \"Heralded generation of ultrafast single photons in pure quantum states,\" Phys. Rev. Lett. 100(13) 133601 (2008) 9. D. Kielpinski, J. F. Corney, and H. M. Wiseman, \"Quantum optical waveform conversion,\" Phys. Rev. Lett. 106, 130501 (2011) 10. B. Brecht, D. V. Reddy, C. Silberhorn, and M. G. Raymer, \"Photon temporal modes: a complete framework for quantum information science,\" Phys. Rev. X 5(4) 041017 (2015) 11. F. Kaneda, B. G. Christensen, J. Ju. Wong, H. S. Park, K. T. McCusker, and P. G. Kwiat, \"Time multiplexed heralded single photon source,\" Optica 2(12) 1010 1013 (2015) 12. R. J. A. Francis Jones, R. A. Hoggarth, and P. J. Mosley, \"All fiber multiplexed source of high purity single photons,\" Optica 3(11) 1270 1273 (2016) 13. W. P. Grice, A. B. U'Ren, and I. A. Walmsley, \"Eliminating frequency and space time correlations in multiphoton states,\" Phys. Rev. A 64(6) 063815 (2001) 14. Z. D. Walton, M. C. Booth, A. V. Sergienko, B. E. Saleh, and M. C. Teich, \"Controllable frequency entanglement via auto phase matched spontaneous parametric down conversion,\" Phys. Rev. A 67(5) 053810 (2003) 15. O. Kuzucu, M. Fiorentino, M. Albota, F. N. C.Wong, and F. Kartner, \"Two photon coincident frequency entanglement via extended phase matching,\" Phys. Rev. Lett. 94(8) 083601 (2005) 16. P. G. Evans, R. S. Bennink, W. P. Grice, T. S. Humble, and J Schaake, \"Bright source of spectrally uncorrelated polarization entangled photons with nearly single mode emission,\" Phys. Rev. Lett. 105(25) 253601 (2010) Vol. 26, No. 3 5 Feb 2018 OPTICS EXPRESS 2764 #314082 Journal (c) 2018 https:/doi.org/10.1364/OE.26.002764 Received 22 Nov 2017; revised 15 Jan 2018; accepted 19 Jan 2018; published 25 Jan 2018 17. A. Eckstein, A. S. Christ, P. J. Mosley, and C. Silberhor, \"Highly efficient single pass source of pulsed single mode twin beams of light,\" Phys. Rev. Lett. 106(1) 013603 (2011) 18. R. B. Jin, R. Shimizu, K. Wakui, H. Benichi, and M. Sasaki, \"Widely tunable single photon source with high purity at telecom wavelength,\" Opt. Express 21(9) 10659 10666 (2013) 19. G. Harder, V. Ansari, B. Brecht, T. Dirmeier, C. Marquardt, and C. Silberhorn, \"An optimized photon pair source for quantum circuits,\" Opt. Express 21(12) 13975 13985 (2013) 20. F. Kaneda, K. Garay Palmett, A. B. U'Ren, and P. G. Kwiat, \"Heralded single photon source utilizing highly nondegenerate, spectrally factorable spontaneous parametric downconversion,\" Opt. Express 24(10) 10733 10747 (2016) 21. J. B. Spring, P. L. Mennea, B. J. Metcalf, P. C. Humphreys, J. C. Gates, H. L. Rogers, C. Soller, B. J. Smith, W. S. Kolthammer, P. G. R. Smith, and I. A. Walmsley, \"Chip based array of near identical, pure, heralded single photon sources,\" Optica 4(1) 90 96 (2017) 22. M. Bellini, F. Marin, S. Viciani, A. Zavatta, and F. T. Arecchi, \"Nonlocal pulse shaping with entangled photon pairs,\" Phys. Rev. Lett. 90(4) 043602 (2003) 23. A. Pe'Er, B. Dayan, A. A. Friesem, and Y. Silberberg, \"Temporal shaping of entangled photons,\" Phys. Rev. Lett. 94(7) 073601 (2005) 24. S. Y. Baek, O. Kwon, and Y. H. Kim, \"Temporal shaping of a heralded single photon wave packet,\" Phys. Rev. A 77(1) 013829 (2008) 25. J. M. Lukens, A. Dezfooliyan, C. Langrock, M. M. Fejer, D. E. Leaird, and A. M. Weiner, \"Orthogonal spectral coding of entangled photons,\" Phys. Rev. Lett. 112(13) 133602 (2014) 26. C. Bernhard, B. Bessire, T. Feurer, and A. Stefanov, \"Shaping frequency entangled qudits,\" Phys. Rev. A 88(3) 032322 (2013) 27. A. B. U'Ren, K. Banaszek, and I. A. Walmsley, \"Photon engineering for quantum information processing,\" Quantum Inf. Comput. 3, 480 (2003) 28. E. Meyer Scott, N. Montaut, J. Tiedau, L.Sansoni, H. Herrmann, T. J. Bartley, and C. Silberhorn, \"Limits on the heralding efficiencies and spectral purities of spectrally filtered single photons from photon pair sources,\" Phys. Rev. A 95(6) 061803 (2017) 29. A. Acin, N. Brunner, N. Gisin, S. Massar, S. Pironio, and V. Scarani, \"Device independent security of quantum cryptography against collective attacks,\" Phys. Rev. Lett. 98(23) 230501 (2007) 30. M. Lucamarini, G. Vallone, I. Gianani, P. Mataloni, and G. Di Giuseppe. \"Device independent entanglement based Bennett 1992 protocol,\" Phys. Rev. A 86(3) 032325 (2012) 31. Michael Varnava, Daniel E Browne, and Terry Rudolph, \"How good must single photon sources and detectors be for efficient linear optical quantum computation?\" Phys. Rev. Lett. 100(6) 060502 (2008) 32. Y. X. Gong, X. B. Zou, T. C. Ralph, S. N. Zhu, and G. C. Guo, \"Linear optical quantum computation with imperfect entangled photon pair sources and inefficient non photon number resolving detectors,\" Phys. Rev. A 81(5) 052303 (2010) 33. Th. Jennewein, M. Barbieri, and A. G. White, \"Single photon device requirements for operating linear optics quantum computing outside the post selection basis,\" J. Mod. Opt. 58(3 4) 276 287 (2011) 34. J. M. Donohue, M. Mastrovich, and K. J. Resch, \"Spectrally engineering photonic entanglement with a time lens,\" Phys. Rev. Lett. 117(24) 243602 (2016) 35. N. Matsuda, \"Deterministic reshaping of single photon spectra using cross phase modulation,\" Sci. Adv. 2(3) e1501223 (2016) 36. M. Allgaier, V. Ansari, L. Sansoni, C. Eigner, V. Quiring, R. Ricken, G. Harder, B. Brecht, and C. Silberhorn, \"Highly efficient frequency conversion with bandwidth compression of quantum light,\" Nat. Commun. 8, 14288 (2017) 37. V. Averchenko, D. Sych, G. Schunk, U. Vogl, C. Marquardt, and G. Leuchs, \"Temporal shaping of single photons enabled by entanglement,\" Phys. Rev. A 96(4) 043822 (2017) 38. K. A. G. Fisher, D. G. England, J. P. W. MacLean, P. J. Bustard, K. J. Resch, and B. J. Sussman, \"Frequency and bandwidth conversion of single photons in a room temperature diamond quantum memory,\" Nat. Commun. 7, 11200 (2016) 39. M. Karpinski, Mi. Jachura, L. J Wright, and B. J Smith, \"Bandwidth manipulation of quantum light by an electro optic time lens,\" Nat. Photonics 11,53 57 (2017) 40. P. T. Callahan, K.Safak, P. Battle, T. D. Roberts, and F. X. Kartner, \"Fiber coupled balanced optical cross correlator using PPKTP waveguides,\" Opt. Express 22(8) 9749 9758 (2014) 41. C. K. Law, I. A. Walmsley, and J. H. Eberly, \"Continuous frequency entanglement: effective finite hilbert space and entropy control,\" Phys. Rev. Lett. 84(23) 5304 5307 (2000) 42. J. H. Eberly, \"Schmidt analysis of pure state entanglement,\" Laser Phys. 16(6) 921 926 (2006) 43. A. Christ, K. Laiho, A. Eckstein, K. N. Cassemiro, and C. Silberhorn, \"Probing multimode squeezing with correlation functions,\" New J. Phys. 13(3) 033027 (2011) 44. W. Mauerer, M. Avenhaus, W. Helwig, and C. Silberhorn, \"How colors influence numbers: Photon statistics of parametric down conversion,\" Phys. Rev. A 80(5) 053815 (2009) 45. A. B. U'Ren, C. Silberhorn, K. Banaszek, I. A. Walmsley, R. K. Erdmann, W. P. Grice, and M. G. Raymer, \"Generation of pure state single photon wavepackets by conditional preparation based on spontaneous parametric downconversion,\" Laser Phys. 15(1) 146 161 (2005) Vol. 26, No. 3 5 Feb 2018 OPTICS EXPRESS 2765", "author_names": [ "A Balagopal V", "", "R E", "S M", "Dilip Yadav M", "P L", "G I", "M J", "M L", "Baskaran M", "Sunil C" ], "corpus_id": 7062207, "doc_id": "7062207", "n_citations": 15, "n_key_citations": 1, "score": 0, "title": "Heralded generation of high purity ultrashort single photons in programmable temporal shapes", "venue": "", "year": 2018 }, { "abstract": "Nonclassical states of light are an essential resource for many emerging quantum technologies and applications ranging from information processing, encrypted communications, and networking to sensing, metrology, and imaging. Nonlinear optical processes in solid state materials are widely used for generating quantum light, including single photons, entangled photon pairs, and quadrature squeezed states. Recent advances in nonlinear photonics have enabled the functionality of benchtop nonlinear instruments to be scaled down to a single chip without sacrificing efficiency or degrading the key performance metrics. The dramatic improvement in the size, weight, power, cost, and stability enabled by photonic integrated circuits has been essential for enabling the chip scale generation, manipulation, and detection of quantum light at a steadily increasing degree of complexity and scale. Within the last decade, the authors have seen the progression from few component photonic circuits operating on two photons to arrays of 18 identical heralded single photon sources and reconfigurable devices operating with more than 650 components for multidimensional entanglement and arbitrary two photon quantum gates. In this review, the authors summarize the history and recent key technological developments of chip scale nonlinear quantum light generation based on integrated nonlinear photonics, recent advances in heterogeneous integrated methods, and approaches for system level integration and demonstrated applications.", "author_names": [ "Galan Moody", "Lin Chang", "Trevor J Steiner", "John E Bowers" ], "corpus_id": 225145200, "doc_id": "225145200", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Chip scale nonlinear photonics for quantum light generation", "venue": "", "year": 2020 }, { "abstract": "Integrated quantum photonics has so far been constrained to two on chip generated photons. We present the first device to wield four photon entanglement, generating both the star and line graph states. Further, we measure record levels of on chip quantum interference. Finally, we bound the leading sources of error, combining a detailed model of the device with Bayesian parameter estimation, paving the way to scalability. Quantum computers promise a paradigm shift in humanity's capability to process information. Meanwhile, measurement based quantum computing based on graph states provides the prevailing architecture for largescale quantum computation [1] Silicon quantum photonics is a high performance, scalable quantum technology platform, boasting circuits of unparalleled scale [2] and simultaneous indistinguishable photon pairs [3] Here, we generate both kinds of four photon graph state using a silicon chip. Four on chip sources of spontaneous four wave mixing generate two Bell pairs in four dual rail qubits. The Bell pairs are then entangled using a two qubit gate, programmably generating either star and line type graph states a first in optics. Then, reconfigurable local operations rotate the state into any of the other four qubit graph states and implement measurement projectors. The photons are subsequently detected off chip by superconducting nanowire single photon detectors. Fig. 1a shows a schematic of the device. Fig. 1: a) Overview of the experiment. Star and line graph states are shown with their locally equivalent states and fidelities. b) A fringe demonstrating record on chip HOM interference. c) Bayesian parameter estimates of on chip photon indistinguishability. Our star and line graph states have fidelities of 0.78+ 0.01 and 0.68+ 0.02 respectively. Further, our on chip Hong Ou Mandel (HOM) interference visibility, VHOM 0.80 0.01, is state of the art, verifying our photons' purity (see Fig. 1b) We also bound the device's dominant sources of error by Bayesian parameter estimation (e.g. Fig. 1c) Our device breaks the multiphoton barrier for integrated quantum photonics, and demonstrates programmable entanglement generation, expediting progress towards quantum computing with photons. [1] R. Raussendorf, Measurement based quantum computation with cluster states, International Journal of Quantum Information 7, 1053 1203 (2009) [2] J. Wang et al. Multidimensional quantum entanglement with large scale integrated optics, Science, eaar7053, (2018) [3] I.I. Faruque et al. On chip quantum interference with heralded photons from two independent micro ring resonator sources in silicon photonics, Optics express, 26, 20379 20395 (2018) CEWQO 2019", "author_names": [ "Jeremy C Adcock", "Caterina Vigliar", "Raffaele Santagati", "Joshua W Silverstone", "Mark G Thompson" ], "corpus_id": 189956826, "doc_id": "189956826", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Reconfigurable four photon graph states on a silicon chip", "venue": "", "year": 2019 }, { "abstract": "Many existing schemes for linear optical quantum computing (LOQC) depend on multiplexing (MUX) which uses dynamic routing to enable near deterministic gates and sources to be constructed using heralded, probabilistic primitives. MUXing accounts for the overwhelming majority of active switching demands in current LOQC architectures. In this manuscript we introduce relative multiplexing (RMUX) a general purpose optimisation which can dramatically reduce the active switching requirements for MUX in LOQC, and thereby reduce hardware complexity and energy consumption, as well as relaxing demands on performance for various photonic components. We discuss the application of RMUX to the generation of entangled states from probabilistic single photon sources, and argue that an order of magnitude improvement in the rate of generation of Bell states can be achieved. In addition, we apply RMUX to the proposal for percolation of a 3D cluster state by Gimeno Segovia et al (2015 Phys. Rev. Lett. 115 020502) and we find that RMUX allows an 2.4x increase in loss tolerance for this architecture.", "author_names": [ "Mercedes Gimeno-Segovia", "Hugo Cable", "Gabriel Joe Mendoza", "Peter J Shadbolt", "Joshua W Silverstone", "Jacques Carolan", "Mark G Thompson", "Jeremy Lloyd O'Brien", "Terry Rudolph" ], "corpus_id": 44834128, "doc_id": "44834128", "n_citations": 23, "n_key_citations": 0, "score": 0, "title": "Relative multiplexing for minimising switching in linear optical quantum computing", "venue": "", "year": 2017 }, { "abstract": "Abstract Quantum information science offers inherently more powerful methods for communication, computation, and precision measurement that take advantage of quantum superposition and entanglement. In recent years, theoretical and experimental advances in quantum computing and simulation with photons have spurred great interest in developing large photonic entangled states that challenge today's classical computers. As experiments have increased in complexity, there has been an increasing need to transition bulk optics experiments to integrated photonics platforms to control more spatial modes with higher fidelity and phase stability. The silicon on insulator (SOI) nanophotonics platform offers new possibilities for quantum optics, including the integration of bright, nonclassical light sources, based on the large third order nonlinearity (kh(3) of silicon, alongside quantum state manipulation circuits with thousands of optical elements, all on a single phase stable chip. How large do these photonic systems need to be? Recent theoretical work on Boson Sampling suggests that even the problem of sampling from e30 identical photons, having passed through an interferometer of hundreds of modes, becomes challenging for classical computers. While experiments of this size are still challenging, the SOI platform has the required component density to enable low loss and programmable interferometers for manipulating hundreds of spatial modes. Here, we discuss the SOI nanophotonics platform for quantum photonic circuits with hundreds to thousands of optical elements and the associated challenges. We compare SOI to competing technologies in terms of requirements for quantum optical systems. We review recent results on large scale quantum state evolution circuits and strategies for realizing high fidelity heralded gates with imperfect, practical systems. Next, we review recent results on silicon photonics based photon pair sources and device architectures, and we discuss a path towards large scale source integration. Finally, we review monolithic integration strategies for single photon detectors and their essential role in on chip feed forward operations.", "author_names": [ "Nicholas Christopher Harris", "Darius Bunandar", "Mihir Pant", "Gregory R Steinbrecher", "Jacob Mower", "Mihika Prabhu", "Tom Baehr-Jones", "Michael Hochberg", "D Englund" ], "corpus_id": 51821976, "doc_id": "51821976", "n_citations": 81, "n_key_citations": 3, "score": 0, "title": "Large scale quantum photonic circuits in silicon", "venue": "", "year": 2016 } ]

[ { "abstract": "Single crystalline thin films of complex oxides show a rich variety of functional properties such as ferroelectricity, piezoelectricity, ferro and antiferromagnetism and so on that have the potential for completely new electronic applications. Direct synthesis of such oxides on silicon remains challenging because of the fundamental crystal chemistry and mechanical incompatibility of dissimilar interfaces. Here we report integration of thin (down to one unit cell) single crystalline, complex oxide films onto silicon substrates, by epitaxial transfer at room temperature. In a field effect transistor using a transferred lead zirconate titanate layer as the gate insulator, we demonstrate direct reversible control of the semiconductor channel charge with polarization state. These results represent the realization of long pursued but yet to be demonstrated single crystal functional oxides on demand on silicon.", "author_names": [ "Saidur Rahman Bakaul", "Claudy Rayan Serrao", "Michelle J Lee", "Chun Wing Yeung", "A Sarker", "Shang-Lin Hsu", "Ajay K Yadav", "Liv R Dedon", "Long You", "Asif Islam Khan", "James David Clarkson", "Chenming Calvin Hu", "Ramamoorthy Ramesh", "Sayeef S Salahuddin" ], "corpus_id": 2857051, "doc_id": "2857051", "n_citations": 77, "n_key_citations": 0, "score": 1, "title": "Single crystal functional oxides on silicon", "venue": "Nature communications", "year": 2016 }, { "abstract": "Abstract In this work the functional behavior of the new Ni 51.2 Ti 23.4 Hf 25.4 high temperature shape memory alloy is investigated along three crystal orientations in compression and compared with the polycrystal behavior. Transformation temperatures were measured following specific aging treatments with the aim to optimize the shape memory and pseudoelastic behaviors. Two aging treatments were then selected in order to fulfill the optimum pseudoelastic behavior (500degC/4 h) and the maximum transformation temperatures (550degC/10 h) without compromising the alloy functionality. High temperature X ray diffraction was utilized to determine the crystal orientations in the austenite phase for the single crystal specimens. The martensite structure was found to be the B19 orthorhombic, in contrast with monoclinic structure for lower Hf contents. Digital image correlation was successively used during isobaric strain temperature experiments on the single crystal and polycrystal specimens. Large strain heterogeneities were found for the single crystals which pair with X ray diffraction data that show un transformed austenite below the martensite finish temperature. This reveals the heterogeneity of the austenite to martensite transformation for the present NiTiHf alloy which explains the divergence between the theoretical and experimental transformation strains. In addition, using digital image correlation it is possible to capture the local strain fields associated with fully transformed specimen regions. The transformation strains calculated locally are in close agreement with the theoretical transformation strains calculated with lattice deformation theory for the cubic austenite to the orthorhombic martensite phase transformation.", "author_names": [ "Luca Patriarca", "Huseyin Sehitoglu", "Elena Panchenko", "Yuriy I Chumlyakov" ], "corpus_id": 139001507, "doc_id": "139001507", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "High temperature functional behavior of single crystal Ni51.2Ti23.4Hf25.4 shape memory alloy", "venue": "", "year": 2016 }, { "abstract": "Developing an understanding of structure activity relationships and reaction mechanisms of catalytic processes is critical to the successful design of highly efficient catalysts. As a fundamental reaction in fuel cells, elucidation of the oxygen reduction reaction (ORR) mechanism at Pt(hkl) surfaces has remained a significant challenge for researchers. Here, we employ in situ electrochemical surface enhanced Raman spectroscopy (SERS) and density functional theory (DFT) calculation techniques to examine the ORR process at Pt(hkl) surfaces. Direct spectroscopic evidence for ORR intermediates indicates that, under acidic conditions, the pathway of ORR at Pt(111) occurs through the formation of HO2* whereas at Pt(110) and Pt(100) it occurs via the generation of OH* However, we propose that the pathway of the ORR under alkaline conditions at Pt(hkl) surfaces mainly occurs through the formation of O2 Notably, these results demonstrate that the SERS technique offers an effective and reliable way for real time investigation of catalytic processes at atomically flat surfaces not normally amenable to study with Raman spectroscopy.The oxygen reduction reaction, catalysed by platinum, is a crucial process in the operation of fuel cells, but the mechanistic pathways through which it occurs remain a matter for debate. Here, the authors use in situ Raman spectroscopy to identify key intermediates for this reaction at different atomically flat platinum surfaces, shedding light on the mechanism.", "author_names": [ "Jin-chao Dong", "Xia-Guang Zhang", "Valentin Briega-Martos", "Xi Jin", "Ji Yang", "Shu Chen", "Zhi-Lin Yang", "De-Yin Wu", "Juan M Feliu", "Christopher T Williams", "Zhongqun Tian", "Jian-feng Li" ], "corpus_id": 139240086, "doc_id": "139240086", "n_citations": 171, "n_key_citations": 0, "score": 0, "title": "In situ Raman spectroscopic evidence for oxygen reduction reaction intermediates at platinum single crystal surfaces", "venue": "", "year": 2019 }, { "abstract": "Design of active and stable Pt based nanoscale electrocatalysts for the oxygen reduction reaction (ORR) will be the key to improving the efficiency of fuel cells that are needed to deliver reliable, affordable and environmentally friendly energy. Here, by exploring the ORR on Pt single crystals, cubo octahedral (polyhedral) Pt NPs with different sizes (ranging from 2 to 7 nm) and 7 8 nm Pt NPs with different shapes (cubo octahedral vs. cube vs. octahedral) we presented a surface science approach capable of rationalizing, and ultimately understanding, fundamental relationships between stability of Pt NPs and activity of the ORR in acidic media. By exploring the potential induced dissolution/re deposition of Pt between 0.05 and 1.3 V, we found that concomitant variations in morphology of Pt(111) and Pt(100) lead to narrowing differences in activity between Pt single crystal surfaces. We also found that regardless of an initial size or shape, NPs are metastable and easily evolve to thermodynamically equilibrated shape and size with very similar activity for the ORR. We concluded that while initially clearly observed, the particle size and shape effects diminish as the particles age to the point that it may appear that the ORR depends neither on the particle size nor particle shape.", "author_names": [ "Dongguo Li", "Chao Wang", "Dusan Strmcnik", "Dusan V Tripkovic", "Xiaolian Sun", "Yijin Kang", "Miaofang Chi", "Joshua D Snyder", "Dennis van der Vliet", "Yifen Tsai", "Vojislav R Stamenkovic", "Shouheng Sun", "Nenad M Markovic" ], "corpus_id": 95606551, "doc_id": "95606551", "n_citations": 142, "n_key_citations": 0, "score": 0, "title": "Functional links between Pt single crystal morphology and nanoparticles with different size and shape: the oxygen reduction reaction case", "venue": "", "year": 2014 }, { "abstract": "We report on the anisotropic optical properties of single crystal tin monosulfide (SnS) The components ea, eb, and ec of the pseudodielectric function tensor <e> <e1> i<e2> spectra are taken from 0.73 to 6.45 eV by spectroscopic ellipsometry. The measured <e> spectra are in a good agreement with the results of the calculated dielectric response from hybrid density functional theory. The <e> spectra show the direct band gap onset and a total of eight above band gap optical structures that are associated with the interband transition critical points (CPs) We obtain accurate CP energies by fitting analytic CP expressions to second energy derivatives of the <e> data. Their probable electronic origins and implications for photovoltaic applications are discussed.", "author_names": [ "Rona E Banai", "Lee A Burton", "Sukgeun Choi", "Florian Hofherr", "Tina Sorgenfrei", "Aron Walsh", "Bobby To", "A Croll", "Jeffrey Brownson" ], "corpus_id": 95679571, "doc_id": "95679571", "n_citations": 49, "n_key_citations": 2, "score": 0, "title": "Ellipsometric characterization and density functional theory analysis of anisotropic optical properties of single crystal a SnS", "venue": "", "year": 2014 }, { "abstract": "Single crystal to single crystal (SCSC) transformations represent some of the most fascinating phenomena in chemistry. They are not only intriguing from a basic science point of view but also provide a means to modify or tune the properties of the materials via the postsynthetic introduction of suitable guest molecules or organic functional groups into their structures. Here, we describe UCY 2, a new flexible Nd(3+ metal organic framework (MOF) which exhibits a unique capability to undergo a plethora of SCSC transformations with some of them being very uncommon. These structural alterations involve the replacement of coordinating solvent molecules of UCY 2 by terminally ligating solvents and organic ligands with multiple functional groups including OH, SH, NH and NH(2) or their combinations, chelating ligands, anions, and two different organic compounds. The SCSC coordinating solvent exchange is thus demonstrated as a powerful method for the functionalization of MOFs.", "author_names": [ "Manolis J Manos", "Eleni J Kyprianidou", "Giannis S Papaefstathiou", "Anastasios J Tasiopoulos" ], "corpus_id": 24416938, "doc_id": "24416938", "n_citations": 42, "n_key_citations": 0, "score": 0, "title": "Insertion of functional groups into a Nd3+ metal organic framework via single crystal to single crystal coordinating solvent exchange.", "venue": "Inorganic chemistry", "year": 2012 }, { "abstract": "Luminescence alterations in solid state materials upon external stimulations have attracted much attention due to their potential for the development of highly functional devices or sensors. We have previously reported the first examples of mechano induced single crystal to single crystal (SCSC) phase transitions of gold(I) isocyanide complexes under concomitant emission color changes. However, the reverse phase transitions of the crystals obtained after mechanical stimulation have not yet been achieved. Herein, a reversible change of the luminescence based on two SCSC phase transitions via mechanical cutting and solvent vapor adsorption is described. Crystallization of a gold(I) complex that bears CF3 and biaryl moieties from CH2Cl2/MeOH afforded a green emitting single crystal packed in a polar space group (Pna21) The green emitting single crystals included MeOH molecules. Upon cutting the crystal under MeOH vapor at 22 degC, the green emitting single crystal spontaneously changed into a centrosymmetric orange emitting single crystal (P1) under concomitant release of MeOH. Remarkably, the initial green emitting crystal could be recovered from the orange emitting crystal by a solvent induced SCSC transition under saturated MeOH vapor. The combination of two different types of SCSC phase transitions enables the reversible structural and photoluminescent alternations.", "author_names": [ "Mingoo Jin", "Toshiki Sumitani", "Hiroyasu Sato", "Tomohiro Seki", "Hajime Ito" ], "corpus_id": 207188528, "doc_id": "207188528", "n_citations": 69, "n_key_citations": 0, "score": 0, "title": "Mechanical Stimulation Triggered and Solvent Vapor Induced Reverse Single Crystal to Single Crystal Phase Transitions with Alterations of the Luminescence Color.", "venue": "Journal of the American Chemical Society", "year": 2018 }, { "abstract": "Abstract Good quality single crystals of 2 amino 4,6 dimethylpyrimidine 4 nitrophenol (AMP4N) were successfully grown by slow evaporation solution technique (SEST) at room temperature using methanol as solvent. The grown crystal was subjected to single crystal XRD (SXRD) and its structure was solved by the direct method using SHELXS program and refined using SHELXL program. The Hirshfeld surfaces analysis was carried out to define theoretically electron density boundary surfaces between the molecules in a grown crystal, which are useful to analyze and view the intermolecular interactions. The powder XRD (PXRD) was carried out to identify the crystalline planes and its strain was also calculated by the Williamson Hall equation. 13C and 1H NMR were recorded to interpret the environment of the molecular structure of the AMP4N crystal. Functional groups of AMP4N crystal were confirmed by Fourier transform infrared (FTIR) spectral analysis. The optical quality of the grown crystal was analyzed by UV Vis NIR spectral analysis. The grown crystal has good optical transparency in the range 410 1100 nm. The thermal behaviour of the crystal has been investigated by thermogravimetric and differential thermal analysis (TG DTA) Chemical etching study was carried out and the etch pit density (EPD) was calculated. The laser damage threshold (LDT) was measured under single shot mode using an Nd: YAG laser at 532 nm. The third order nonlinear optical properties such as refractive index (n2) absorption coefficient (b) and susceptibility (kh(3) were studied using the Z scan technique at 532 nm with a continuous wave (CW) solid state laser.", "author_names": [ "P Karuppasamy", "T Kamalesh", "K Anitha", "Shaik Abdul Kalam", "Muthu Senthil Pandian", "P Ramasamy", "Sunil Verma", "S Venugopal Rao" ], "corpus_id": 51944071, "doc_id": "51944071", "n_citations": 28, "n_key_citations": 0, "score": 0, "title": "Synthesis, crystal growth, structure and characterization of a novel third order nonlinear optical organic single crystal: 2 Amino 4,6 Dimethyl Pyrimidine 4 nitrophenol", "venue": "", "year": 2018 }, { "abstract": "Summary Metal organic frameworks (MOFs) have intriguing and tunable photophysical properties owing to predesignable structures from well defined metal and/or organic chromophores. We propose a one pot two step assembly strategy for engineering dual functional coordination interspace where two kinds of organic linkers are segregated in predefined positions. This design endows the three dimensional coordination framework with unidirectional deformation character, leading to an orientation dependent and pressure responsive photoluminescence color change. For the first time, unique piezofluorochromic anisotropism is achieved and can be accumulated stepwise and visualized by a metal organic framework single crystal, providing a basic model for application in stimuli responsive photoluminescence sensing, barcoding, signal switching, harvesting, and magnifying micro devices.", "author_names": [ "Cheng-Xia Chen", "Zhangwen Wei", "Ya-Nan Fan", "Peiyang Su", "Yeye Ai", "Qian-Feng Qiu", "Kai Wu", "Shaoyun Yin", "Mei Pan", "Chengyong Su" ], "corpus_id": 139201458, "doc_id": "139201458", "n_citations": 35, "n_key_citations": 0, "score": 0, "title": "Visualization of Anisotropic and Stepwise Piezofluorochromism in an MOF Single Crystal", "venue": "", "year": 2018 }, { "abstract": "The design and synthesis of functional materials with desired properties is the ultimate goal for chemical pursuers. Single crystal to single crystal (SCSC) transformations are an important component of solid state reactions. These transformations not only create new materials but also provide an opportunity to explore the process of forming a chemical bond, which is conducive to making function oriented crystal synthesis a reality. In this review, we provide a broad overview of SCSC transformations that take place in polymers or metal organic frameworks, and classify them into several groups based on their various inducing stimuli, such as UV light, loss/uptake of solvent vapor, temperature change, mechanical force and their synergic impact. Unlike other reviews, the SCSC transformations discussed in this paper are confined to transformations via an absolutely liquid free mode (both the reactant and product are in the solid phase) while those involving liquids, in which the transformation occurs in a recrystallization manner, are strictly excluded. These dynamic processes all involve the breakage and formation of covalent or non covalent bonds, accompanied by drastic structural rearrangement in the crystalline phase. Changes in the physical properties of these complexes resulting from SCSC transformations are also illustrated. Thanks to the regular characteristics of crystal structures before and after the reactions, the transformation processes may provide deep insights into the rational design of crystalline materials.", "author_names": [ "Wenwen He", "Shun-li Li", "Ya-Qian Lan" ], "corpus_id": 13716082, "doc_id": "13716082", "n_citations": 24, "n_key_citations": 0, "score": 0, "title": "Liquid free single crystal to single crystal transformations in coordination polymers", "venue": "", "year": 2018 } ]

[ { "abstract": "Abstract We report results of design and optimization of high average output power picosecond and nanosecond laser operating at 1342 nm wavelength. Developed for selective micromachining, this DPSS laser is comprised of master oscillator, regenerative amplifier and output pulse control module. Passively mode locked by means of semiconductor saturable absorber mirror and pumped with 808 nm wavelength Nd:YVO 4 master oscillator emits 12.5 ps pulses at repetition rate of 55 MHz with average output power of ~100 mW. The four pass confocal delay line forms a longest part of the oscillator cavity in order to suppress thermo mechanical misalignment. Picked from the train seed pulses were injected to the cavity of regenerative amplifier based on composite Nd:YVO 4 crystal with diffusion bonded segments of multiple Nd doping concentration end pumped at 880 nm wavelength. Laser produces pulses of ~13 ps duration at 300 kHz repetition rate with average output power of 11 W and nearly diffraction limited beam quality of M 2 ~1.03. Attained high peak power ~2.8 MW facilitates conversion to the 2nd, 3rd and 6th harmonics at 671 nm, 447 nm and 224 nm wavelengths with 80% 50% and 15% efficiency respectively. Without seeding the regenerative amplifier transforms to electro optically cavity dumped Q switched laser providing 10 ns output pulses at high repetition rates with beam propagation factor of M 2 ~1.06.", "author_names": [ "Aleksej M Rodin", "M Ya Grishin", "Andrejus Michailovas" ], "corpus_id": 116932065, "doc_id": "116932065", "n_citations": 14, "n_key_citations": 0, "score": 1, "title": "Picosecond laser with 11 W output power at 1342 nm based on composite multiple doping level Nd:YVO4 crystal", "venue": "", "year": 2016 }, { "abstract": "We report recent progress on GaN on diamond high electron mobility transistors (HEMTs) fabricated using a low temperature device transfer process. The devices were first fabricated on a GaN on SiC epitaxial wafer and were subsequently separated from the SiC and bonded onto a high thermal conductivity diamond substrate at low temperature. The resulting $12 \\times 50~\\mu \\text{m} GaN on diamond HEMTs demonstrated the state of the art electrical characteristics, including a maximum drain current density of 1.2 A/mm and a peak transconductance of 390 mS/mm. CW load pull measurements at 10 GHz yielded an RF output power density of 11 W/mm with 51% associated power added efficiency. Device measurements show that the GaN on diamond devices maintained slightly lower channel temperatures than their GaN on SiC counterparts while delivering 3.6 times higher RF power within the same active area. These results demonstrate that the GaN device transfer process is capable of preserving intrinsic GaN on SiC transistor electrical performance while taking advantage of the excellent thermal properties of diamond substrates.", "author_names": [ "Pane Chane Chao", "Kenneth K Chu", "Carlton T Creamer", "Jose A Diaz", "Thomas Yurovchak", "Michael S Shur", "Raymond L Kallaher", "Craig D McGray", "G D Via", "J D Blevins" ], "corpus_id": 12736950, "doc_id": "12736950", "n_citations": 47, "n_key_citations": 4, "score": 0, "title": "Low Temperature Bonded GaN on Diamond HEMTs With 11 W/mm Output Power at 10 GHz", "venue": "IEEE Transactions on Electron Devices", "year": 2015 }, { "abstract": "A wirelessly powered 11 mW transceiver for implantable sensors has been designed and demonstrated through 35 mm of porcine heart tissue. The prototype occupies 1 mm x 1 mm in 65nm CMOS with an external receive antenna. The IC consists of a rectifier, regulator, demodulator, modulator, controller, and sensor interface. The forward link transfers power and data on a 1.32 GHz carrier using low depth ASK modulation that minimizes impact on power delivery and achieves from 4 to 20 Mbps with 0.3 pJ/bit at 4 Mbps. The backscattering link modulates the antenna impedance with a configurable load for operation in diverse biological environments and achieves 2 Mbps at 0.7 pJ/bit. The device supports TDMA, allowing for simultaneous operation of multiple sensors.", "author_names": [ "Anatoly Yakovlev", "Ji Hoon Jang", "Daniel Pivonka" ], "corpus_id": 7364505, "doc_id": "7364505", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "A 11mW Sub pJ/bit reconfigurable transceiver for mm sized wireless implants", "venue": "Proceedings of the IEEE 2013 Custom Integrated Circuits Conference", "year": 2013 }, { "abstract": "We present a narrow linewidth continuous laser source with over 11 W output power at 780 nm, based on single pass frequency doubling of an amplified 1560 nm fibre laser with 36% efficiency. This source offers a combination of high power, simplicity, mode quality and stability. Without any active stabilization, the linewidth is measured to be below 10 kHz. The fibre seed is tunable over 60 GHz, which allows access to the D2 transitions in 87Rb and 85Rb, providing a viable high power source for laser cooling as well as for large momentum transfer beamsplitters in atom interferometry. Sources of this type will pave the way for a new generation of high flux, high duty cycle degenerate quantum gas experiments.", "author_names": [ "Sharmila S Sane", "Shayne Bennetts", "John E Debs", "Carlos C N Kuhn", "Gordon D McDonald", "Paul A Altin", "John D Close", "Nicholas P Robins" ], "corpus_id": 207321659, "doc_id": "207321659", "n_citations": 68, "n_key_citations": 0, "score": 0, "title": "11 W narrow linewidth laser source at 780 nm for laser cooling and manipulation of Rubidium.", "venue": "Optics express", "year": 2012 }, { "abstract": "A wirelessly powered 11 mW transceiver for implantable sensors has been designed and demonstrated through 35 mm of porcine heart tissue. The prototype occupies 1 mm x 1 mm in 65nm CMOS with an external receive antenna. The IC consists of a rectifier, regulator, demodulator, modulator, controller, and sensor interface. The forward link transfers power and data on a 1.32 GHz carrier using low depth ASK modulation that minimizes impact on power delivery and achieves from 4 to 20 Mbps with 0.3 pJ/bit at 4 Mbps. The backscattering link modulates the antenna impedance with a configurable load for operation in diverse biological environments and achieves 2 Mbps at 0.7 pJ/bit. The device supports TDMA, allowing for simultaneous operation of multiple sensors.", "author_names": [ "Anatoly Yakovlev", "Ji Hoon Jang", "Daniel Pivonka", "Ada S Y Poon" ], "corpus_id": 32102417, "doc_id": "32102417", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "A 11mW Sub pJ/bit reconfigurable transceiver for mm sized wireless implants", "venue": "CICC", "year": 2013 }, { "abstract": "We report on a high power polycrystalline Er:YAG ceramic laser in band pumped by a cladding pumped Er, Yb fiber laser wavelength locked at 1532 nm with a volume Bragg grating. Using 1.0 at Er3+ doped ceramic as the gain medium and an output coupler of 10% transmission, the laser had a threshold pump power of ~1.5 W and generated 11 W of continuous wave output at 1645 nm for 23.3 W of incident pump power at 1532 nm, corresponding to a slope efficiency with respect to incident pump power of 51%", "author_names": [ "X F Yang", "Deyuan Shen", "Tingjie Zhao", "Hao Chen", "Jianmin Zhou", "Jianguo Li", "Huamin Kou", "Yu-bai Pan" ], "corpus_id": 120402278, "doc_id": "120402278", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "In band pumped Er:YAG ceramic laser with 11 W of output power at 1645 nm", "venue": "", "year": 2011 }, { "abstract": "This paper presents the highest average power passively Q switched Nd:vanadate laser, to the best of our knowledge. A maximum average output power greater than 11 W was demonstrated using a Nd:YVO4 bounce geometry laser operating at 1064 nm in TEM00 mode, with a spatially stigmatic design. Pulse energies greater than 58 uJ and peak powers in excess of 1.9 kW were obtained; the maximum repetition rate recorded was 190 kHz, close to the upper limit achievable with Cr4+:YAG saturable absorbers.", "author_names": [ "Gabrielle M Thomas", "Michael J Damzen" ], "corpus_id": 42628216, "doc_id": "42628216", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Passively Q switched Nd:YVO4 laser with greater than 11 W average power.", "venue": "Optics express", "year": 2011 }, { "abstract": "A fully integrated humidity sensor for a smart RFID sensor platform has been realized in 0.16mm standard CMOS technology. It consists of a top metal finger structure capacitor covered with a humidity sensitive layer, combined with a micro power flexible sensor interface based on a second order incremental delta sigma converter. The interface can be easily reconfigured to compensate for process variation of the sensing element. In a measurement time of 10.2 ms, the interface performs a 13 bits capacitance to digital conversion while consuming only 5.85 mA from 1.8 V supply. In combination with the co integrated sensor capacitor, it thus provides a humidity to digital conversion with a resolution of 0.1% RH in the range of 20% to 90% RH at only 107 nJ per measurement. This represents a significant improvement in energy efficiency compared to existing capacitive sensor interfaces with comparable performance.", "author_names": [ "Zhichao Tan", "Roel Daamen", "Aurelie Humbert", "Kamran Souri", "Youngcheol Chae", "Youri Ponomarev", "Michiel A P Pertijs" ], "corpus_id": 2016967, "doc_id": "2016967", "n_citations": 35, "n_key_citations": 3, "score": 0, "title": "A 1.8V 11mW CMOS smart humidity sensor for RFID sensing applications", "venue": "IEEE Asian Solid State Circuits Conference 2011", "year": 2011 }, { "abstract": "We report power scaling experiments of a GaInNAs/GaAs based semiconductor disk laser operating at ~1180 nm. Using a single gain chip cooled to mount temperature of ~10 degC we obtained 11 W of output power. For efficient thermal management we used a water cooled microchannel mount and an intracavity diamond heat spreader. Laser performance was studied using different spot sizes of the pump beam on the gain chip and different output couplers. Intracavity frequency doubling experiments led to generation of ~6.2 W of laser radiation at ~590 nm, a wavelength relevant for the development of sodium laser guide stars.", "author_names": [ "Ville-Markus Korpijarvi", "Tomi Leinonen", "Janne Puustinen", "Antti Harkonen", "Mircea D Guina" ], "corpus_id": 7140476, "doc_id": "7140476", "n_citations": 39, "n_key_citations": 0, "score": 0, "title": "11 W single gain chip dilute nitride disk laser emitting around 1180 nm.", "venue": "Optics express", "year": 2010 }, { "abstract": "High power operation of a cladding pumped Tm doped broadband superfluorescent fiber source in the two micron wavelength regime is described. Predominately single ended operation was achieved using a simple all fiber geometry without the use of a high reflectivity mirror or fiber Bragg gratings. The source produced >11 W of single ended amplified spontaneous emission output spanning the wavelength range from approximately 1930 nm to 1988 nm for a launched diode pump power of approximately 40 W at approximately 790 nm, corresponding to a slope efficiency of 38% with respect to launched pump power. The wavelength spectrum of the superfluorescent source spanned the range from approximately 1650 to 2100 nm with a bandwidth (FWHM) of 100 nm for output power levels of 20 mW.", "author_names": [ "Deyuan Shen", "Lee Pearson", "P Wang", "Jayanta Kumar Sahu", "W Andrew Clarkson" ], "corpus_id": 22220794, "doc_id": "22220794", "n_citations": 42, "n_key_citations": 1, "score": 0, "title": "Broadband Tm doped superfluorescent fiber source with 11 W single ended output power.", "venue": "Optics express", "year": 2008 } ]

[ { "abstract": "Predictive Maintenance (PdM) offers one possibility to improve productivity in semiconductor manufacturing. Current research on PdM mainly focuses on its technical implementation. By applying discrete event simulation, we provide results how maintenance strategies influence operational performance, and how PdM contributes to an overall improvement of productivity in wafer fabrication.", "author_names": [ "K -H G Bae", "B Feng", "Sin-Bom Kim", "Sanja Lazarova-Molnar", "Z Zheng", "T Roeder", "Renee M Thiesing" ], "corpus_id": 230119796, "doc_id": "230119796", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "USING DISCRETE EVENT SIMULATION FOR POTENTIAL ANALYSIS OF PREDICTIVE MAINTENANCE IN SEMICONDUCTOR MANUFACTURING", "venue": "", "year": 2020 }, { "abstract": "The accuracy of data mining based predictive maintenance often relies on extensive process and machine knowledge to enable appropriate feature selection and data preprocessing. Measurement data obtained may be asynchronous and result in inaccurate features, affecting the accuracy of maintenance prediction. To overcome this drawback, this paper introduces an approach to automatically select a feature subset through a genetic algorithm. The full feature set is created based on different sliding windows characterizing different time shifts on adopted statistical metrics of the measurement data. The fitness function of the genetic algorithm is then developed based on the preliminary fitting of a hidden Markov model (HMM) on the selected subset of features and assumed machines' condition in the training data. Ultimately the fittest subset of features is used to enable HMM based predictive maintenance. The proposed approach is evaluated using data from semi conductor wafer production equipment, recorded over a period of one year.", "author_names": [ "Jakob Kinghorst", "Omid Geramifard", "Ming Luo", "Hian-Leng Chan", "Khoo Yong", "Jens Folmer", "Minjie Zou", "Birgit Vogel-Heuser" ], "corpus_id": 35215142, "doc_id": "35215142", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Hidden Markov model based predictive maintenance in semiconductor manufacturing: A genetic algorithm approach", "venue": "2017 13th IEEE Conference on Automation Science and Engineering (CASE)", "year": 2017 }, { "abstract": "In order to occupy a competitive position in semiconductor industry the most important challenges a fabrication plant has to face are the reduction of manufacturing costs and the increase of production yield. Predictive maintenance is one possible way to address these challenges. In this paper we present an implementation of a universally applicable methodology based on the theory of regression trees and Random Forests to predict tool maintenance operations. We exemplarily show the application of the method by constructing a model for predictive maintenance of an ion implantation tool. To fit the problem adequately and to allow a descriptive interpretation we introduce the remaining time until next maintenance as a response variable. By using R and adequately analyzing data acquired during wafer processing a Random Forest model is constructed. We can show that under typical production conditions the model is able to predict a recurring maintenance operation sufficiently accurate. This example shows that better planning of maintenance operations allows for an increase in productivity and a reduction of downtime costs.", "author_names": [ "Peter Scheibelhofer", "Dietmar Gleispach", "Guenther Hayderer", "Ernst Stadlober" ], "corpus_id": 41940118, "doc_id": "41940118", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "A Methodology for Predictive Maintenance in Semiconductor Manufacturing", "venue": "", "year": 2016 }, { "abstract": "Over the past two years the Predictive Maintenance (PdM) capability in semiconductor manufacturing has migrated from Proof of Concept (PoC) and univariate Fault Detection (FD) extrapolation mechanisms to fab wide solutions that are (1) robust to typical process and equipment disturbances, (2) extensible so as to provide solution approaches that are portable across instances of a tool type and across tool types, and (3) maintainable so as to provide solutions that are useful for long periods of time. A number of advancements have facilitated this advancement including solutions for porting modeling components across process and equipment types, mechanisms for incorporating process and equipment knowledge into models, mechanisms for determining model context (e.g. recipe) dependency, methods for model optimization to fab financials, and methods for rejecting run time disturbances in PdM modeling. As a result of these and other innovations, the landscape of PdM in semiconductor manufacturing has rapidly advanced to the point that, from a technical perspective, solutions are now available for fab wide PdM realization.", "author_names": [ "Jimmy Iskandar", "James R Moyne", "K Subrahmanyam", "Parris C M Hawkins", "Michael Armacost" ], "corpus_id": 24080473, "doc_id": "24080473", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Predictive Maintenance in semiconductor manufacturing", "venue": "2015 26th Annual SEMI Advanced Semiconductor Manufacturing Conference (ASMC)", "year": 2015 }, { "abstract": "", "author_names": [ "Jimmy Iskandar", "James R Moyne", "K Subrahmanyam", "Parris C M Hawkins", "Michael Armacost" ], "corpus_id": 112917230, "doc_id": "112917230", "n_citations": 7, "n_key_citations": 2, "score": 0, "title": "Predictive Maintenance in Semiconductor Manufacturing Moving to Fab Wide Solutions", "venue": "", "year": 2015 }, { "abstract": "Predictive Maintenance methods are aimed to obtain reliable estimates of the remaining life cycle of an equipment from time series of suitable process parameters, named \"health factors\" typically exhibiting a monotone evolution associated with the equipment wear. The present study was motivated by the predictive maintenance of a dry etching equipment within a semiconductor manufacturing process. The optimal prediction of the health factor, represented by the cooling helium flow, must cope with noisy measurements of the health factor (possibly masking its monotonicity) and non uniform sampling times. The problem is formulated as a stochastic filtering problem in which a stochastic process has to be optimally predicted based on noisy and irregularly sampled observations. In particular, a hidden Gamma process model is proposed in order to capture all the features of the health factor, namely its nonnegativity and nonnegativity of its derivative. Since this filtering problem is not amenable to a closed form solution, a numerical Monte Carlo approach based on particle filtering is developed. Additionally, an adaptive parameter identification procedure is proposed to achieve the best trade off between promptness and noise insensitivity.", "author_names": [ "Andrea Schirru", "Simone Pampuri", "Giuseppe De Nicolao" ], "corpus_id": 11079109, "doc_id": "11079109", "n_citations": 23, "n_key_citations": 2, "score": 0, "title": "Particle filtering of hidden Gamma processes for robust Predictive Maintenance in semiconductor manufacturing", "venue": "2010 IEEE International Conference on Automation Science and Engineering", "year": 2010 }, { "abstract": "The present paper is motivated by the application of Predictive Maintenance (PM) techniques in the semiconductor manufacturing environment: such techniques are able, using process data, to make reliable predictions of residual equipment lifetime. The employment of PM yields positive fallouts on the productive process in form of unscheduled downtime reduction, increased spare parts availability and improved overall production quality. One of the main challenges in PM modeling regards the data driven assessment of relevant process variables when insufficient expert knowledge is available. In this paper, survival models theory is employed jointly with l1 penalization techniques: this allows to obtain sparse models able to select the meaningful process variables and simultaneously predict the remaining lifetime of an equipment. Additionally, frailty modeling techniques are employed to concurrently handle several productive equipments of the same type, exploiting their similarities to increase prediction accuracy. The proposed methodology is validated, illustrating promising results, by means of a semiconductor manufacturing dataset.", "author_names": [ "Simone Pampuri", "Andrea Schirru", "Cristina De Luca", "Giuseppe De Nicolao" ], "corpus_id": 13134101, "doc_id": "13134101", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Proportional hazard model with l1 Penalization applied to Predictive Maintenance in semiconductor manufacturing", "venue": "2011 IEEE International Conference on Automation Science and Engineering", "year": 2011 }, { "abstract": "In this paper, the predictive maintenance(PdM) technology was applied to the semiconductor manufacturing equipment and the DBSCAN algorithm parameters were optimized. The data obtained from the semiconductor equipment was obtained using acceleration sensors and was used to determine the conditions of the equipment. To simulate the malfunction condition of the equipment, the virtual error data was artificially generated. The DBSCAN clustering algorithm is applied to both acceleration sensor data and virtual error data to trace the moving of the center point of each cluster. By tracing the center points, the appropriate time for equipment maintenance can be determined. Also, the parameters of the DBSCAN algorithm were optimized using one way factorial design to improve to determine the exact time of maintenance.", "author_names": [ "Heesu Yoon", "Seung-Soo Han" ], "corpus_id": 210992856, "doc_id": "210992856", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Clustering Parameter Optimization of Predictive Maintenance Algorithm for Semiconductor Equipment Using One way Factorial Design", "venue": "2019 19th International Conference on Control, Automation and Systems (ICCAS)", "year": 2019 }, { "abstract": "The goal of this work was to implement a wireless RFID based Sensor Network in the UHF frequency region inside a semiconductor cleaning machine to supplement existing sensors in order to simplify usability and reduce production costs. The sensors are chosen in a way to extract useful information about the status of the semiconductor production machine to invoke specific system maintenance, thereby reducing maintenance times and costs. The great challenges are to obtain passive UHF receiver tags and sensors that reliably have to be detected among hundreds of other sensors in an electromagnetically complex and chemically harsh environment using innovative packaging and novel integration technologies.", "author_names": [ "Thomas Moldaschl", "Ales Travnik", "A Frank", "Jochen Bardong", "Heinz Cramer", "Herbert Kastberger", "Matthias Weitlaner", "Michael Jerne", "Alexey Nazarov", "Christina Hirschl" ], "corpus_id": 215865215, "doc_id": "215865215", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "RFID based Wireless Sensor Network for Semiconductor Manufacturing Equipment to enable Predictive Maintenance", "venue": "", "year": 2019 }, { "abstract": "Semiconductor equipment is closely related to production yield and should be periodically inspected to maintain the performance. However, traditional equipment maintenance methods have difficulty responding to sudden failures and economic losses due to unpredicted situation. Recently, predictive maintenance technologies have been actively studied, with many advantages, such as the ability to predict the right time of equipment maintenance in advance to ensure system stability and maximize return on capital. Economic gains and increased equipment stability are particularly important in the semiconductor industry. In this paper, we developed a predictive maintenance technique for wafer transport robots. A technology was developed to predict the failure of the robot by tracing the median values of clusters of the frequency data, which were acquired using acceleration sensors attached on the handler of the robot. By applying this system to the wafer transport robot, the simulation results showed that the time of repair can be predicted in real time.", "author_names": [ "Hyeong-Gyun Kim", "Heesu Yoon", "Ji Hyun Yoo", "Hyun-il Yoon", "Seung-Soo Han" ], "corpus_id": 146118998, "doc_id": "146118998", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Development of Predictive Maintenance Technology for Wafer Transfer Robot using Clustering Algorithm", "venue": "2019 International Conference on Electronics, Information, and Communication (ICEIC)", "year": 2019 } ]

[ { "abstract": "We observed a 32 fold increase in the spontaneous emission rate of InGaN/GaN quantum well (QW) at 440 nm by employing surface plasmons (SPs) probed by time resolved photoluminescence spectroscopy. We explore this remarkable enhancement of the emission rates and intensities resulting from the efficient energy transfer from electron hole pair recombination in the QW to electron vibrations of SPs at the metal coated surface of the semiconductor heterostructure. This QW SP coupling is expected to lead to a new class of super bright and high speed light emitting diodes (LEDs) that offer realistic alternatives to conventional fluorescent tubes.", "author_names": [ "Koichi Okamoto", "Isamu Niki", "Axel Scherer", "Yukio Narukawa", "Takashi Mukai", "Yoichi Kawakami" ], "corpus_id": 122961840, "doc_id": "122961840", "n_citations": 322, "n_key_citations": 5, "score": 1, "title": "Surface plasmon enhanced spontaneous emission rate of InGaN/GaN quantum wells probed by time resolved photoluminescence spectroscopy", "venue": "", "year": 2005 }, { "abstract": "Since 1993, InGaN light emitting diodes (LEDs) have been improved and commercialized1,2, but these devices have not fulfilled their original promise as solid state replacements for light bulbs as their light emission efficiencies have been limited2. Here we describe a method to enhance this efficiency through the energy transfer between quantum wells (QWs) and surface plasmons (SPs) SPs can increase the density of states and the spontaneous emission rate in the semiconductor3,4,5,6,7,8,9, and lead to the enhancement of light emission by SP QW coupling10,11. Large enhancements of the internal quantum efficiencies (eint) were measured when silver or aluminium layers were deposited 10 nm above an InGaN light emitting layer, whereas no such enhancements were obtained from gold coated samples. Our results indicate that the use of SPs would lead to a new class of very bright LEDs, and highly efficient solid state light sources.", "author_names": [ "Koichi Okamoto", "Isamu Niki", "Alexander Shvartser", "Yukio Narukawa", "Takashi Mukai", "Axel Scherer" ], "corpus_id": 15031578, "doc_id": "15031578", "n_citations": 1254, "n_key_citations": 15, "score": 0, "title": "Surface plasmon enhanced light emitters based on InGaN quantum wells", "venue": "Nature materials", "year": 2004 }, { "abstract": "Optical properties of InGaN/GaN multi quantum well (MQW) structures with a nanolayer of Ag/SiO2 nanoparticle (NP) on top were studied. Modeling and optical absorption (OA) measurements prove that the NPs form localized surface plasmons (LSP) structure with a broad OA band peaked near 440 460 nm and the fringe electric field extending down to about 10 nm into the GaN layer. The presence of this NP LSP electrical field increases the photoluminescence (PL) intensity of the MQW structure by about 70% and markedly decreases the time resolved PL (TRPL) relaxation time due to the strong coupling of MQW emission to the LSP mode.", "author_names": [ "Lee Woon Jang", "Dae-Woo Jeon", "Trilochan Sahoo", "Dong-Seob Jo", "Jin-Woo Ju", "Seungjai Lee", "Jong Hyeob Baek", "Jin-Kyu Yang", "Jung-Hoon Song", "A Y Polyakov", "Inhwan Dennis Lee" ], "corpus_id": 16515042, "doc_id": "16515042", "n_citations": 34, "n_key_citations": 1, "score": 0, "title": "Localized surface plasmon enhanced quantum efficiency of InGaN/GaN quantum wells by Ag/SiO2 nanoparticles.", "venue": "Optics express", "year": 2012 }, { "abstract": "Group III nitrides are efficient light emitters. The modification of internal optoelectronic properties of these materials due to strain, external or internal electric field are an area of interest. Insertion of metal nanoparticles (MNPs) (Ag, Au etc) inside the V shaped inverted hexagonal pits (IHP) of InGaN/GaN quantum wells (QWs) offers the potential of improving the light emission efficiencies. We have observed redshift and blueshift due to the Au MNPs and Ag MNPs respectively. This shift could be due to the electric field created by the MNPs through electrostatic image charge. We have studied the ultrafast carrier dynamics of carriers in hybrid InGaN/GaN QWs. The change in quantum confinement stark effect due to MNPs plays an important role for slow and fast carrier dynamics. We have also observed the image charge effect on the ultrafast differential transmission measurement due to the MNPs. We have studied the non linear absorption spectroscopy of these materials. The QWs behave as a discharging of a nanocapacitor for the screening of the piezoelectric field due to the photo excited carriers. We have separated out screening and excitonic bleaching components from the main differential absorption spectra of InGaN/GaN QWs.", "author_names": [ "Meg Mahat" ], "corpus_id": 134423105, "doc_id": "134423105", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Ultrafast Spectroscopy of Hybrid Ingan/gan Quantum Wells", "venue": "", "year": 2012 }, { "abstract": "The coupling between localized surface plasmons (LSPs) within silver nanostructures and excitons in a silicon rich silicon nitride (SiNx) matrix has been demonstrated via the Purcell effect. A simple model is employed for the estimation of the Purcell factor as well as the average position of excitons within a luminescence matrix. The estimated average position of the excitons is located at approximately 40 nm beneath the top surface of the SiNx films. The approaches for further improving the optoelectrical properties of the luminescence matrix are anticipated based on the model we adopted. The optimization of the thickness of the luminescence matrix as well as the size and shape of metal nanostructures may be the alternative approaches. Besides, the application of multilayers with the luminescence matrix inserted between barrier layers (we defined it as confined structures here) may be also an available choice. Our work may provide a deep comprehension on the coupling between LSPs and excitons, which is not limited to a certain luminescence material but with unconfined structures.", "author_names": [ "Feng Wang", "Dongsheng Li", "Deren Yang", "Duan-lin Que" ], "corpus_id": 14476806, "doc_id": "14476806", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "The coupling between localized surface plasmons and excitons via Purcell effect", "venue": "Nanoscale Research Letters", "year": 2012 }, { "abstract": "Surface plasmonics from metal nanoparticles have been demonstrated as an effective way of improving the performance of low efficiency light emitters. However, reducing the inherent losses of the metal nanoparticles remains a challenge. Here we study the enhancement properties by Ag nanoparticles for InGaN/GaN quantum well structures. By using a thin SiN dielectric layer between Ag and GaN we manage to modify and improve surface plasmon coupling effects, and we attribute this to the improved scattering of the nanoparticles at the quantum well emission wavelength. The results are interpreted using numerical simulations, where absorption and scattering cross sections are studied for different sized particles on GaN and GaN/SiN substrates.", "author_names": [ "Ahmed Fadil", "Daisuke Iida", "Yuntian Chen", "Jun Ma", "Yiyu Ou", "Paul Michael Petersen", "Haiyan Ou" ], "corpus_id": 14750346, "doc_id": "14750346", "n_citations": 31, "n_key_citations": 1, "score": 0, "title": "Surface plasmon coupling dynamics in InGaN/GaN quantum well structures and radiative efficiency improvement", "venue": "Scientific reports", "year": 2014 }, { "abstract": "We obtained very bright light emission from CdSe quantum dots (QDs) by using surface plasmon coupling. Both the photoluminescence intensities and decay rates are dramatically increased when QDs are located on evaporated gold films.", "author_names": [ "Koichi Okamoto", "S Vyawahare", "Axel Scherer" ], "corpus_id": 7659939, "doc_id": "7659939", "n_citations": 142, "n_key_citations": 2, "score": 0, "title": "Surface plasmon enhanced light emission from CdSe quantum dot nanocrystals", "venue": "2006 Conference on Lasers and Electro Optics and 2006 Quantum Electronics and Laser Science Conference", "year": 2006 }, { "abstract": "Insulating spacer layers of MgO were used to identify the enhancement mechanisms of the ZnO band edge and visible luminescence in ZnO MgO Ag and ZnO MgO Au multilayers. Purcell enhancement of the ZnO band edge emission by both Ag and Au surface plasmon polaritons is confirmed by demonstrating that the exponential decay of this emission as a function of increasing MgO thickness is consistent with the Ag and Au SPP evanescent decay lengths. Local surface plasmons excited in Ag and Au nanoparticles and rough films are also shown to enhance the ZnO visible donor acceptor pair photoluminescence by dipole dipole scattering, again with an appropriate dependence on the thickness of the MgO spacer layer. We also confirm that both Ag and Au nanoparticles enhance the ZnO band edge emission by charge transfer when the MgO spacer layer is absent.", "author_names": [ "Benjamin J Lawrie", "Richard F Haglund", "Richard Mu" ], "corpus_id": 11318666, "doc_id": "11318666", "n_citations": 85, "n_key_citations": 2, "score": 0, "title": "Enhancement of ZnO photoluminescence by localized and propagating surface plasmons.", "venue": "Optics express", "year": 2009 }, { "abstract": "The authors demonstrate the metallic structure dependent surface plasmon (SP) coupling behaviors with a blue emitting InGaN/GaN quantum well (QW) which is 10nm away from the metallic structures. The SP QW coupling behaviors in the areas of semiconductor surface coated with silver thin film and silver nanoparticles are compared. It is found that both the suppression of photoluminescence (PL) intensity and the reduction of time resolved PL (TRPL) decay time strongly depend on the metallic morphology. A phenomenological model of carrier relaxation in the SP QW coupling process is built to fit the TRPL decay profiles for calibrating the reasonable decay time constants of carrier and SP.", "author_names": [ "Cheng-Yen Chen", "Dong-Ming Yeh", "Yen-Cheng Lu", "Chih-Chung Yang" ], "corpus_id": 120272831, "doc_id": "120272831", "n_citations": 44, "n_key_citations": 0, "score": 0, "title": "Dependence of resonant coupling between surface plasmons and an InGaN quantum well on metallic structure", "venue": "", "year": 2006 }, { "abstract": "By measuring external quantum efficiency and differential carrier lifetimes of blue and green GaN based light emitting diodes depending on injection current, efficiency droop effect is proposed to be related to both carrier leakage and Auger recombination.", "author_names": [ "Xiao Meng", "Lai Wang", "Jiadong Yu", "Zhi-biao Hao", "Yi Luo" ], "corpus_id": 112340621, "doc_id": "112340621", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Differential Carrier Lifetime Analysis on GaN Based LED's Quantum Efficiency", "venue": "2014 Asia Communications and Photonics Conference (ACP)", "year": 2014 } ]

[ { "abstract": "AbstractNature uses organic molecules for light harvesting and photosynthesis, but most man made water splitting catalysts are inorganic semiconductors. Organic photocatalysts, while attractive because of their synthetic tunability, tend to have low quantum efficiencies for water splitting. Here we present a crystalline covalent organic framework (COF) based on a benzo bis(benzothiophene sulfone) moiety that shows a much higher activity for photochemical hydrogen evolution than its amorphous or semicrystalline counterparts. The COF is stable under long term visible irradiation and shows steady photochemical hydrogen evolution with a sacrificial electron donor for at least 50 hours. We attribute the high quantum efficiency of fused sulfone COF to its crystallinity, its strong visible light absorption, and its wettable, hydrophilic 3.2 nm mesopores. These pores allow the framework to be dye sensitized, leading to a further 61% enhancement in the hydrogen evolution rate up to 16.3 mmol g 1 h 1. The COF also retained its photocatalytic activity when cast as a thin film onto a support.The inherent synthetic tuneability of organic materials makes them attractive in photocatalysis, but they tend to have low quantum efficiencies for water splitting. A crystalline covalent organic framework featuring a benzo bis(benzothiophene sulfone) moiety has now been shown to exhibit high activity for photochemical hydrogen evolution from water.", "author_names": [ "Xiao-yan Wang", "Linjiang Chen", "Samantha Yu-Ling Chong", "Marc A Little", "Yongzhen Wu", "Weihong Zhu", "Rob Clowes", "Yong Yan", "Martijn A Zwijnenburg", "Reiner Sebastian Sprick", "Andrew I Cooper" ], "corpus_id": 205563500, "doc_id": "205563500", "n_citations": 328, "n_key_citations": 1, "score": 1, "title": "Sulfone containing covalent organic frameworks for photocatalytic hydrogen evolution from water", "venue": "Nature Chemistry", "year": 2018 }, { "abstract": "A benzodifuran based donor acceptor covalent organic framework was synthesized and employed for efficient simulated sunlight driven photocatalytic hydrogen evolution from water, which exhibited a superior and steady hydrogen evolution rate of 1390 mmol g 1 h 1 and an outstanding apparent quantum yield (AQY) of 7.8% was obtained at 420 nm.", "author_names": [ "Fu-Cheng Zhu", "Qian-Qian Lin", "Jing-lan Kan", "Ke-Hui Xie", "Sha Li", "Yan Geng", "Yu-Bin Dong" ], "corpus_id": 233741989, "doc_id": "233741989", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Rational design of benzodifuran functionalized donor acceptor covalent organic frameworks for photocatalytic hydrogen evolution from water.", "venue": "Chemical communications", "year": 2021 }, { "abstract": "Visible light driven hydrogen (H2) production from water is a promising strategy to convert and store solar energy as chemical energy. Covalent organic frameworks (COFs) are front runners among different classes of organic photocatalysts. Photocatalytic activity of COFs depends on numerous factors such as electronic band gap, crystallinity, surface area, exci ton migration, stability of transient species, charge separation and transport, etc. However, it is challenging to fine tune all these factors simultaneously to enhance the photocatalytic activity. Hence, in this report, an effort has been made to understand the interplay of these factors and identify the key factors for efficient photocatalytic H2 production through structure property activity relationship. Careful molecular engineering allowed us to optimize all the above plausible factors impacting on the overall catalytic activities of a series of isoreticular COFs. The present study determines three prime factors: light absorption, charge carrier generation, and their transport, which influence the photocatalytic H2 production of COFs in much greater extent than the other factors.", "author_names": [ "Samrat Ghosh", "Akinobu Nakada", "Maximilian A Springer", "Takahiro Kawaguchi", "Katsuaki Suzuki", "Hironori Kaji", "Igor A Baburin", "Agnieszka Beata Kuc", "Thomas Heine", "Hajime Suzuki", "Ryu Abe", "Shu Seki" ], "corpus_id": 218468625, "doc_id": "218468625", "n_citations": 29, "n_key_citations": 0, "score": 0, "title": "Identification of Prime Factors to Maximize the Photocatalytic Hydrogen Evolution of Covalent Organic Frameworks.", "venue": "Journal of the American Chemical Society", "year": 2020 }, { "abstract": "Electron transfer is the rate limiting step in photocatalytic water splitting. Viologen and its derivatives are able to act as electron transfer mediators (ETMs) to facilitate the rapid electron transfer from photosensitizers to active sites. Nevertheless, the electron transfer ability often suffers from the formation of stable dipole structure through the coupling between cationic radical containing viologen derived ETMs, by which the electron transfer process becomes restricted. Herein, cyclic diquats, a kind of viologen derived ETM, are integrated into a 2,2' bipyridine based covalent organic framework (COF) through a post quaternization reaction. The content and distribution of embedded diquat ETMs are elaborately controlled, leading to the favorable site isolated arrangement. The resulting materials integrate the photosensitizing units and ETMs into one system, exhibiting the enhanced hydrogen evolution rate (34600 mmol h 1 g 1 and sustained performances when compared to a single module COF and a COF/ETM mixture. The integration strategy applied in a 2D COF platform promotes the consecutive electron transfer in photochemical processes through the multi component cooperation.", "author_names": [ "Zhen Mi", "Ting Zhou", "Weijun Weng", "Junjuda Unruangsri", "Ke Hu", "Wuli Yang", "Changchun Wang", "Kai A I Zhang", "Jia Guo" ], "corpus_id": 231689240, "doc_id": "231689240", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Covalent Organic Frameworks Enabling Site Isolation of Viologen Derived Electron Transfer Mediators for Stable Photocatalytic Hydrogen Evolution.", "venue": "Angewandte Chemie", "year": 2021 }, { "abstract": "Abstract A facile and effective impregnation combined with photo deposition approach was adopted to deposit cadmium sulfide (CdS) nanoparticles on CTF 1, a covalent triazine based frameworks (CTFs) In this system, CTF 1 not only acted as supporter but also served as photocatalyst and electron donor. The performance of the obtained CdS deposited CTF 1 (CdS CTF 1) nanocomposite was evaluated by H2 evolution reaction under visible light irradiation. As a result, CdS CTF 1 exhibited high H2 production from water, far surpassing the CdS/CTF 1 nanocomposite, in which CdS was deposited via solvothermal method. The high activity of CdS CTF 1 was attributed to the confined CdS nanoparticles with small size, leading to expose more active sites. In addition, time resolved spectroscopy indicated that the superior performance of CdS CTF 1 also can be ascribed to the fast electron transfer rate and injection efficiency (KET 0.18 x 109 s 1, einj 39.38% between CdS and CTF 1 layers, which are 3.83 times faster and 4.84 times higher than that of CdS/CTF 1 nanocomposite. This work represents the first example on using covalent organic frameworks (COFs) as a support and electron donor for fabricating novel CdS COF nanocomposite system and its potential application in solar energy transformations.", "author_names": [ "Dengke Wang", "Hui Zeng", "Xin Xiong", "Mei-Feng Wu", "Mei Ling Xia", "Maoliang Xie", "Jianping Zou", "Shenglian Luo" ], "corpus_id": 208732314, "doc_id": "208732314", "n_citations": 42, "n_key_citations": 0, "score": 0, "title": "Highly efficient charge transfer in CdS covalent organic framework nanocomposites for stable photocatalytic hydrogen evolution under visible light", "venue": "", "year": 2020 }, { "abstract": "Covalent organic frameworks have recently gained increasing attention in photocatalytic hydrogen generation from water. However, their structure property activity relationship, which should be beneficial for the structural design, is still far away explored. Herein, we report the designed synthesis of four isostructural porphyrinic two dimensional covalent organic frameworks (MPor DETH COF, M H2, Co, Ni, Zn) and their photocatalytic activity in hydrogen generation. Our results clearly show that all four covalent organic frameworks adopt AA stacking structures, with high crystallinity and large surface area. Interestingly, the incorporation of different transition metals into the porphyrin rings can rationally tune the photocatalytic hydrogen evolution rate of corresponding covalent organic frameworks, with the order of CoPor DETH COF H2Por DETH COF NiPor DETH COF ZnPor DETH COF. Based on the detailed experiments and calculations, this tunable performance can be mainly explained by their tailored charge carrier dynamics via molecular engineering. This study not only represents a simple and effective way for efficient tuning of the photocatalytic hydrogen evolution activities of covalent organic frameworks at molecular level, but also provides valuable insight on the structure design of covalent organic frameworks for better photocatalysis.", "author_names": [ "Rufan Chen", "Yuan Ma", "Arindam Mal", "Xiaoya Gao", "Lei Gao", "Lijie Qiao", "Xu-Bing Li", "Li-Zhu Wu", "Cheng Wang" ], "corpus_id": 232091450, "doc_id": "232091450", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Rational design of isostructural 2D porphyrin based covalent organic frameworks for tunable photocatalytic hydrogen evolution", "venue": "Nature communications", "year": 2021 }, { "abstract": "Efficient polymer photocatalysts that mimic natural photosynthesis to generate H2 through the visible light promoted splitting of water are ideal systems for the conversion of solar energy into usable fuel with high energy density and in an environmentally friendly manner. In this article, we review recent reports on donor acceptor based p conjugated polymers as photocatalysts, including conjugated linear polymers, microporous polymers, triazine frameworks, covalent organic frameworks, polymer dots, and other related organic polymers, which show superior photocatalytic activity and robust stability under visible light irradiation, for hydrogen production. Moreover, their syntheses and material design strategies, photophysical properties, proposed mechanisms, and applications are systematically summarized. Finally, recent research on and challenges related to organic polymer photocatalysts are discussed. This minireview will help readers to more easily understand the recent advances in and future direction of this field.", "author_names": [ "Jayachandran Jayakumar", "Ho-Hsiu Chou" ], "corpus_id": 213516898, "doc_id": "213516898", "n_citations": 47, "n_key_citations": 0, "score": 0, "title": "Recent Advances in Visible Light Driven Hydrogen Evolution from Water using Polymer Photocatalysts", "venue": "", "year": 2020 }, { "abstract": "Covalent triazine based frameworks (CTFs) are a subclass of conjugated microporous polymers (CMPs) that can be used as organic photocatalysts for photocatalytic hydrogen evolution from water. Seven materials with varied spacer units from phenylene to quarterphenylene were synthesized, either by trifluoromethanesulfonic acid (TfOH) catalysis from nitriles or by Suzuki Miyaura polycondensation. The photocatalytic performance under visible light of all materials was systematically studied in the presence of a hole scavenger, showing that both synthesis routes produce CTFs with similar hydrogen evolution rates (HER) but different optical properties. The highest hydrogen evolution rate in the cyclotrimerized series was found for CTF 2 with an apparent quantum yield of 1.6% at 420 nm in a mixture of water and triethanolamine with a platinum co catalyst. Based on (TD )DFT calculations, the highest performance was expected for CTF 1 and this discrepancy is explained by a trade off between increased light absorption and decreased thermodynamic driving force.", "author_names": [ "Christian B Meier", "Reiner Sebastian Sprick", "Adriano Monti", "Pierre Guiglion", "Jet-Sing M Lee", "Martijn A Zwijnenburg", "Andrew I Cooper" ], "corpus_id": 99741573, "doc_id": "99741573", "n_citations": 86, "n_key_citations": 2, "score": 0, "title": "Structure property relationships for covalent triazine based frameworks: The effect of spacer length on photocatalytic hydrogen evolution from water", "venue": "", "year": 2017 }, { "abstract": "Solar hydrogen (H2) evolution from water utilizing covalent organic frameworks (COFs) as heterogeneous photosensitizers has gathered significant momentum by virtue of the COFs' predictive structural design, long range ordering, tunable porosity, and excellent light harvesting ability. However, most photocatalytic systems involve rare and expensive platinum as the co catalyst for water reduction, which appears to be the bottleneck in the development of economical and environmentally benign solar H2 production systems. Herein, we report a simple, efficient, and low cost all in one photocatalytic H2 evolution system composed of a thiazolo[5,4 d]thiazole linked COF (TpDTz) as the photoabsorber and an earth abundant, noble metal free nickel thiolate hexameric cluster co catalyst assembled in situ in water, together with triethanolamine (TEoA) as the sacrificial electron donor. The high crystallinity, porosity, photochemical stability, and light absorption ability of the TpDTz COF enables excellent long term H2 production over 70 h with a maximum rate of 941 mmol h 1 g 1, turnover number TONNi 103, and total projected TONNi 443 until complete catalyst depletion. The high H2 evolution rate and TON, coupled with long term photocatalytic operation of this hybrid system in water, surpass those of many previously known organic dyes, carbon nitride, and COF sensitized photocatalytic H2O reduction systems. Furthermore, we gather unique insights into the reaction mechanism, enabled by a specifically designed continuous flow system for non invasive, direct H2 production rate monitoring, providing higher accuracy in quantification compared to the existing batch measurement methods. Overall, the results presented here open the door toward the rational design of robust and efficient earth abundant COF molecular co catalyst hybrid systems for sustainable solar H2 production in water.", "author_names": [ "Bishnu P Biswal", "Hugo A Vignolo-Gonzalez", "Tanmay Banerjee", "Lars Grunenberg", "Gokcen Savasci", "Kerstin Gottschling", "Jurgen Nuss", "Christian Ochsenfeld", "Bettina V Lotsch" ], "corpus_id": 195772549, "doc_id": "195772549", "n_citations": 88, "n_key_citations": 0, "score": 0, "title": "Sustained Solar H2 Evolution from a Thiazolo[5,4 d]thiazole Bridged Covalent Organic Framework and Nickel Thiolate Cluster in Water", "venue": "Journal of the American Chemical Society", "year": 2019 }, { "abstract": "The development of robust synthetic routes to stable covalent organic frameworks (COFs) is important to broaden the range of applications for these materials. We report here a simple and efficient three component assembly reaction between readily available aldehydes, amines and elemental sulfur via a C H functionalization and oxidative annulation under transition metal free conditions. Five thiazole linked COFs (TZ COFs) were synthesized using this method. These materials showed high levels of crystallinity, high specific surface areas, and excellent physicochemical stability. The photocatalytic applications of TZ COFs were investigated and TZ COF 4 gave high sacrificial hydrogen evolution rates from water (up to 4296 mmol h 1 g 1 under visible light irradiation) coupled with high stability and recyclability, with sustained hydrogen evolution for 50 hrs.", "author_names": [ "Kewei Wang", "Zhifang Jia", "Yang Bai", "Xue Lian Wang", "Sophie Hodgkiss", "Linjiang Chen", "Samantha Yu-Ling Chong", "Xiao-yan Wang", "Hao-Lin Yang", "Yongjie Xu", "Feng Feng", "John W Ward", "Andrew I Cooper" ], "corpus_id": 219174290, "doc_id": "219174290", "n_citations": 28, "n_key_citations": 0, "score": 0, "title": "Synthesis of Stable Thiazole Linked Covalent Organic Frameworks via a Multicomponent Reaction.", "venue": "Journal of the American Chemical Society", "year": 2020 } ]

[ { "abstract": "As efficiency is one of the bottlenecks of device simulation, we propose to employ deep neural networks to generate two dimensional electrostatic potential profiles for efficiency. Supervising with previously obtained simulation results for various BJT devices, we train deep neural networks to generate an electrostatic potential profile as an initial guess for a non equilibrium condition with estimating carrier densities by the frozen field simulation. With the generated potential profiles, we significantly reduce the number of Newton iterations without loss of accuracy.", "author_names": [ "Seung-Cheol Han", "Jonghyun Choi", "Sung-Min Hong" ], "corpus_id": 226267566, "doc_id": "226267566", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Electrostatic Potential Profile Generator for Two Dimensional Semiconductor Devices", "venue": "2020 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD)", "year": 2020 }, { "abstract": "Numerical iterative methods of solution of the one dimensional basic two carrier transport equations describing the behavior of semiconductor junctions under both steady state and transient conditions are presented. The methods are of a very general character: none of the conventional assumptions and restrictions are introduced, and freedom is available in the choice of the doping profile, generation recombination law, mobility dependencies, injection level. and boundary conditions applied solely at the external contacts. For a specified arbitrary input signal of either current or voltage (as a function of time) the solution yields terminal properties and all the quantities of interest in the interior of the device, such as carrier densities, electric field, electrostatic potential, particle and displacement currents, as functions of position (and time) The work is divided into two parts. In Part I a numerical method of solution of the steady state problem, already available in the literature, is improved and extended, and is applied to a two contact and a three contact device. The analytical formulation of the original method is shown to be unsuitable for generating a sound numerical algorithm sufficiently accurate and valid for high reverse bias conditions. Difficulties and limitations are exposed and overcome by an improved formulation extended to any bias condition. As a simple application of the improved formulation, \"exact\" and first order theory results for an idealized N P structure are presented and compared. The poorness of some of the basic assumptions of the conventional first order theory is exposed, in spite of a satisfactory agreement between the exact and first order results of the terminal properties for particular bias conditions. Results for an N P N transistor are also reported and the inadequacy of the one dimensional model discussed. The time dependent analysis of the problem is presented in Part II. The fundamental equations are rearranged to an equivalent set of three non linear partial differential equations more suitable for numerical methods. A highly non uniform two dimensional mesh, subject to maintenance of constant truncation errors in both spatial and time domains of certain pointwise operations, is chosen for the discretization of the problem, in view of the variation of most quantities over extreme ranges within short regions. Consequently an implicit discretization scheme is selected for the second order partial differential equations of the parabolic type in order to avoid restrictions on the mesh size, without endangering numerical stability. An iterative procedure is necessary at each instant of time to cope with the several non linearities of the problem and to achieve consistency between the internal distributions and the generating equations. This procedure is easily generalized to incorporate equations pertinent to networks of passive elements and ideal generators connected to the semiconductor device. Results for a particular single junction structure under typical time dependent excitations of external current and terminal voltage, and for an N P diode interacting with an external resistor under switching conditions. are reported and discussed in detail. Considerable attention is focused on the numerical analysis of the steady state and transient problems in order to achieve a numerical algorithm sufficiently sound and efficient to cope with the several difficulties of the problem, such as the small differences between nearly equal numbers, the variation of most quantities over extremely wide ranges in short regions, and the stability conditions related to the discretization of partial differential equations of the parabolic type.", "author_names": [ "A De Mari" ], "corpus_id": 118123146, "doc_id": "118123146", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Accurate Numerical Steady State and Transient One Dimensional Solutions of Semiconductor Devices", "venue": "", "year": 1968 }, { "abstract": "Exact solution of two dimensional (2D) Poisson's equation for fully depleted double gate silicon on insulator metal oxide semiconductor field effect transistor is derived using three zone Green's function solution technique. Framework consists of consideration of source drain junction curvature. 2D potential profile obtained forms the basis for estimation of threshold voltage. Temperature dependence of front surface potential distribution, back surface potential distribution and front gate threshold voltage are modeled using temperature sensitive parameters. Applying newly developed model, surface potential and threshold voltage sensitivities to gate oxide thickness have been comprehensively investigated. Device simulation is performed using ATLAS 2D (SILVACO, 4701 Patrick Henry Drive, Bldg. Santa Clara, CA 95054 USA) device simulator, and the results obtained are compared with the proposed 2D model. The model results are found to be in good agreement with the simulated data. Copyright (c) 2013 John Wiley Sons, Ltd.", "author_names": [ "Rajiv Sharma", "Sujata Pandey", "Shail Bala Jain" ], "corpus_id": 108688364, "doc_id": "108688364", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Green's function approach for modeling of electrostatic effects in nanoscale fully depleted double gate silicon on insulator metal oxide semiconductor field effect transistors", "venue": "", "year": 2014 }, { "abstract": "A two dimensional mathematical model is developed to predict the internal behavior of power transistors operating under steady state conditions. This model includes the internal self heating effects in power transistors and is applicable to predict the transistor behavior under high current and high voltage operating conditions. The complete set of partial differential equations governing the bipolar semiconductor device behavior under nonisothermal conditions is solved by numerical techniques without assuming internal junctions and other conventional approximations. Input parameters for this model are the dimension of the device, doping profile, mobility expressions, generation recombination model, and the boundary conditions for external contacts. Computer results of the analysis of a typical power transistor design are presented for specified operating conditions. The current density, electrostatic potential, carrier charge density, and temperature distribution plots within the transistor structure illustrate the combined effect of the electrothermal interaction, base conductivity modulation, current crowding, base pushout, space charge layer widening, and current spreading phenomena in power transistors.", "author_names": [ "Santosh P Gaur", "D H Navon" ], "corpus_id": 19895087, "doc_id": "19895087", "n_citations": 93, "n_key_citations": 1, "score": 0, "title": "Two dimensional carrier flow in a transistor structure under nonisothermal conditions", "venue": "IEEE Transactions on Electron Devices", "year": 1976 }, { "abstract": "Summary form only given, as follows. A two dimensional mathematical model is developed to predict the internal behavior of power transistors operating under steady state conditions. This model includes the internal self heating effects in power transistors and is applicable to predict the transistor behavior under high current and high voltage operating conditions. The complete set of partial differential equations governing the bipolar semiconductor device behavior under non isothermal conditions is solved by numerical techniques without assuming internal junctions and other conventional approximations. No restrictions are made on the choice of the doping profile, mobility dependence, boundary conditions for external contacts, generation recombination model and the injection level. Computed results of the analysis of a typical power transistor design are presented for various operating conditions. The current density, electrostatic potential, carrier charge density and temperature distribution plots within the transistor structure illustrate the combined effect of the electro thermal interaction, base conductivity modulation, current crowding, base push out, space charge layer widening and current spreading phenomena in power transistors.", "author_names": [ "Santosh P Gaur", "D H Navon" ], "corpus_id": 115108478, "doc_id": "115108478", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Two dimensional carrier flow in a transistor structure under non isothermal conditions", "venue": "", "year": 1974 }, { "abstract": "A two dimensional numerical solution of electrostatic potential and electric field profiles are presented for lightly doped nano scale Double Gate Metal Oxide Semiconductor Field Effect Transistor (DG MOSFET) We have developed quasi static (QS) model for evaluating bulk and inversion charges based on symmetric linearization model. We have also shown the non quasi static (NQS) effect on the charge due to a time varying gate voltage. It is seen that various symmetries of DG MOSFET characteristics with respect to source/drain interchange is maintained in quasi static as well as non quasi static version of the symmetrically linearized model. The variation of the threshold voltage with the varying width of the device is evaluated and presented. The results have been compared and contrasted with reported analytical model for QS condition for the purpose of verification of the model. The variation of threshold voltage along the width of the device is also predicted. This numerical model can be extended to analyze the transport phenomenon in sub 30 nm channel length DG MOSFETs.", "author_names": [ "Deepanjan Datta", "A Ananda Prasad Sarab", "Sudeb Dasgupta" ], "corpus_id": 42820760, "doc_id": "42820760", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Two dimensional numerical modeling of lightly doped nano scale double gate MOSFET", "venue": "Microelectron. J.", "year": 2006 }, { "abstract": "The control of coherent electrons is becoming relevant in emerging devices as (semi )ballistic transport is observed within nanometer semiconductor structures at room temperature. The evolution of a wave packet representing an electron in a semiconductor can be manipulated using specially shaped potential profiles with convex or concave features, similar to refractive lenses used in optics. Such electrostatic lenses offer the possibility, for instance, to concentrate a single wave packet which has been invoked by a laser pulse, or split it up into several wave packets. Moreover, the shape of the potential profile can be dynamically changed by an externally applied potential, depending on the desired behaviour. The evolution of a wave packet under the influence of a two dimensional potential the electrostatic lens is investigated by computing the physical densities using the Wigner function. The latter is obtained by using the signed particle Wigner Monte Carlo method.", "author_names": [ "Paul Ellinghaus", "Mihail Nedjalkov", "Siegfried Selberherr" ], "corpus_id": 15434535, "doc_id": "15434535", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "The Influence of Electrostatic Lenses on Wave Packet Dynamics", "venue": "LSSC", "year": 2015 }, { "abstract": "The measurement of potentials associated with dopant atoms in semiconductors at nanometer spatial resolution using off axis electron holography is known to be affected by the presence of the surfaces of thin specimens. In particular, the potential across a p n junction is often found to be lower than would be expected from predicted properties of bulk devices. Here we present simulations of two dimensional potential profiles within a thin p n junction. We find that the potential across the p n junction is always smaller, when projected through the specimen, than would be expected from the properties of the bulk material. Crucially, the step in potential across the junction is independent of the value of the potential on the surface of the specimen for high dopant concentrations >10 17 cm 3 The simulations are compared with experimental data. Although they can account for some of the reduction in the observed potential, they do not fully explain the experimental results.", "author_names": [ "Philippa K Somodi", "Rafal E Dunin-Borkowski", "A C Twitchett", "Crispin H W Barnes", "Paul A Midgley" ], "corpus_id": 98117931, "doc_id": "98117931", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Simulations of the electrostatic potential in a thin silicon specimen containing a p n junction", "venue": "", "year": 2004 }, { "abstract": "We study the unitary propagation of a two particle one dimensional Schrodinger equation by means of the Split Step Fourier method, to study the coherent evolution of a spatially indirect exciton (IX) in semiconductor heterostructures. The mutual Coulomb interaction of the electron hole pair and the electrostatic potentials generated by external gates and acting on the two particles separately are taken into account exactly in the two particle dynamics. As relevant examples, step/downhill and barrier/well potential profiles are considered. The space and time dependent evolutions during the scattering event as well as the asymptotic time behavior are analyzed. For typical parameters of GaAs based devices, the transmission or reflection of the pair turns out to be a complex two particle process, due to comparable and competing Coulomb, electrostatic, and kinetic energy scales. Depending on the intensity and anisotropy of the scattering potentials, the quantum evolution may result in excitation of the IX internal degrees of freedom, dissociation of the pair, or transmission in small periodic IX wavepackets due to dwelling of one particle in the barrier region. We discuss the occurrence of each process in the full parameter space of the scattering potentials and the relevance of our results for current excitronic technologies.", "author_names": [ "Federico Grasselli", "Andrea Bertoni", "Guido Goldoni" ], "corpus_id": 30955393, "doc_id": "30955393", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Space and time dependent quantum dynamics of spatially indirect excitons in semiconductor heterostructures.", "venue": "The Journal of chemical physics", "year": 2015 }, { "abstract": "Electron holography (EH) based on transmission electron microscope (TEM) is widely recognized as a powerful interferometric technique to image and quantify electric and magnetic fields for a variety of physical and chemical applications [1] Off axis EH has been successfully applied for accurate quantitative two dimensional (2D) mapping of intrinsic electrostatic potentials arising from material dependent mean inner potentials or semiconductor s dopant profiles, where the target objects are in the stationary state and isolated from external electric bias [2] But for measuring exotic properties of an electrically biased material or an operando device, a global electric field has to be inevitably involved, which is typically nonuniform and also nonlinear to applied voltages. In these scenarios, reference background approximation was often used but sometimes tended to cause nonnegligible artifacts. Thus, it is critical to develop a new strategy to overcome these drawbacks and achieve more accurate measurements.", "author_names": [ "Kaizhou He", "John Cumings" ], "corpus_id": 4277565, "doc_id": "4277565", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A New Design for Measuring Potentials in Operando Nanoelectronic Devices by Electron Holography", "venue": "", "year": 2014 } ]

[ { "abstract": "Silicon crystallized in the usual cubic (diamond) lattice structure has dominated the electronics industry for more than half a century. However, cubic silicon (Si) germanium (Ge) and SiGe alloys are all indirect bandgap semiconductors that cannot emit light efficiently. The goal 1 of achieving efficient light emission from group IV materials in silicon technology has been elusive for decades 2 6 Here we demonstrate efficient light emission from direct bandgap hexagonal Ge and SiGe alloys. We measure a sub nanosecond, temperature insensitive radiative recombination lifetime and observe an emission yield similar to that of direct bandgap group III V semiconductors. Moreover, we demonstrate that, by controlling the composition of the hexagonal SiGe alloy, the emission wavelength can be continuously tuned over a broad range, while preserving the direct bandgap. Our experimental findings are in excellent quantitative agreement with ab initio theory. Hexagonal SiGe embodies an ideal material system in which to combine electronic and optoelectronic functionalities on a single chip, opening the way towards integrated device concepts and information processing technologies. A hexagonal (rather than cubic) alloy of silicon and germanium that has a direct (rather than indirect) bandgap emits light efficiently across a range of wavelengths, enabling electronic and optoelectronic functionalities to be combined on a single chip.", "author_names": [ "Elham M T Fadaly", "Alain Dijkstra", "Jens Rene Suckert", "Dorian Ziss", "Marvin A J van Tilburg", "Chenyang Mao", "Yizhen Ren", "Victor T van Lange", "Ksenia Korzun", "Sebastian Kolling", "Marcel A Verheijen", "David Busse", "Claudia Rodl", "Jurgen Furthmuller", "Friedhelm Bechstedt", "J Stangl", "Jonathan J Finley", "Silvana Botti", "Jos E M Haverkort", "Erik P A M Bakkers" ], "corpus_id": 207870211, "doc_id": "207870211", "n_citations": 79, "n_key_citations": 1, "score": 2, "title": "Direct bandgap emission from hexagonal Ge and SiGe alloys", "venue": "Nature", "year": 2020 }, { "abstract": "Novel group IV nanostructures were fabricated and the optical properties of such nanostructures were investigated for monolithic integration of optically active materials with silicon. The SnxGe1 x alloy system was studied due to the previous demonstration of an indirect to direct energy bandgap transition for strain relieved SnxGe1 x films on Si(001) In addition, quantum confined structures of Sn were fabricated and the optical properties were investigated. Due to the small electron effective mass of a Sn, quantum confinement effects are expected at relatively large radii. Coherently strained, epitaxial SnxGe1 x films on Ge(001) substrates were synthesized with film thickness exceeding 100 nm for the first time. The demonstration of dislocation free SnxGe1 x films is a step toward the fabrication of silicon based integrated infrared optoelectronic devices. The optical properties of coherently strained SnxGe1 x/Ge(001) alloys were investigated both theoretically and experimentally. Deformation potential theory calculations were performed to predict the effect of coherency strain on the extrema points of the conduction band and the valence band. The energy bandgap of SnxGe1 x/Ge(001) alloys was measured via Fourier transform infrared spectroscopy. Coherency strain did not change the SnxGe1 x energy bandgap when the strain axis was along [001] but deformation potential theory predicted the absence of an indirect to direct energy bandgap transition when the strain axis was along [111] In addition to being the only group IV alloy exhibiting a direct energy bandgap, when grown beyond a critical thickness, SnxGe1 x/Ge(001) exhibits an interesting phenomenon during MBE growth. Sn segregates via surface diffusion to the crest of a surface undulation during growth and forms ordered Sn enriched SnxGe1 x rods oriented along [001] The SnxGe1 x alloy system was used as a model system to gain insight to the physical mechanisms governing self assembly and ordering during molecular beam epitaxy. Sn nanowires were fabricated in anodic alumina templates with lengths exceeding 1 mm and diameters on the order of 40 nm. Anodic alumina templates can be fabricated non lithographically with ordered domains of hexagonally packed pores greater than 1 mm and pore densities on the order of 1011 cm 2. The achievement of single crystal Sn nanowires fabricated using pressure injection in porous alumina templates was demonstrated. The fabrication of a Sn quantum dots embedded in Ge was achieved by annealing 1 mm thick SnxGe1 x films at 750degC. The measured diameter of the quantum dots was 32 nm and a 10% size variation was observed. Quantum size effects were observed in a Sn quantum dots. Optical transmittance measurements yield a value of 0.45 eV for the direct energy bandgap as a result of quantum confinement. A high degree of tunability of the bandgap energy with the quantum dot radius is expected for a Sn. Thus quantum confined structures of a Sn are promising for optoelectronic device applications.", "author_names": [ "Regina Ragan" ], "corpus_id": 135541931, "doc_id": "135541931", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Direct Energy Bandgap Group IV Alloys and Nanostructures", "venue": "", "year": 2002 }, { "abstract": "In this paper we investigate the influence of n type doping in Ge light emitting diodes on Si substrates on the room temperature emission spectrum. The layer structures are grown with a special low temperature molecular beam epitaxy process resulting in a slight tensile strain of 0.13% The Ge LED's show a dominant direct bandgap emission with shrinking bandgap at the G point in dependence of n type doping level. The emission shift (38 meV at 1020cm 3) is mainly assigned to bandgap narrowing at high doping. The electroluminescence intensity increases with doping concentrations up to 3x1019cm 3 and decreases sharply at higher doping levels. The integrated direct gap emission intensity increases superlinear with electrical current density. Power exponents vary from about 2 at low doping densities up to 3.6 at 1020cm 3 doping density.", "author_names": [ "Michael Oehme", "Martin Gollhofer", "Daniel Widmann", "Marc Schmid", "Mathias Kaschel", "Erich Kasper", "Jorg Schulze" ], "corpus_id": 2712907, "doc_id": "2712907", "n_citations": 65, "n_key_citations": 2, "score": 0, "title": "Direct bandgap narrowing in Ge LED's on Si substrates.", "venue": "Optics express", "year": 2013 }, { "abstract": "Recent advances in the synthetic growth of nanowires have given access to crystal phases that in bulk are only observed under extreme pressure conditions. Here, we use first principles methods based on density functional theory and many body perturbation theory to show that a suitable mixing of hexagonal Si and hexagonal Ge yields a direct bandgap with an optically permitted transition. Comparison of the calculated radiative lifetimes with typical values of nonradiative recombination mechanisms indicates that optical emission will be the dominant recombination mechanism. These findings pave the way to the development of silicon based optoelectronic devices, thus far hindered by the poor light emission efficiency of cubic Si.", "author_names": [ "Xavier Cartoixa", "Maurizia Palummo", "Hakon Ikaros T Hauge", "Erik P A M Bakkers", "Riccardo Rurali" ], "corpus_id": 206741070, "doc_id": "206741070", "n_citations": 39, "n_key_citations": 1, "score": 0, "title": "Optical Emission in Hexagonal SiGe Nanowires.", "venue": "Nano letters", "year": 2017 }, { "abstract": "We present a comprehensive, up to date compilation of band parameters for the technologically important III V zinc blende and wurtzite compound semiconductors: GaAs, GaSb, GaP, GaN, AlAs, AlSb, AlP, AlN, InAs, InSb, InP, and InN, along with their ternary and quaternary alloys. Based on a review of the existing literature, complete and consistent parameter sets are given for all materials. Emphasizing the quantities required for band structure calculations, we tabulate the direct and indirect energy gaps, spin orbit, and crystal field splittings, alloy bowing parameters, effective masses for electrons, heavy, light, and split off holes, Luttinger parameters, interband momentum matrix elements, and deformation potentials, including temperature and alloy composition dependences where available. Heterostructure band offsets are also given, on an absolute scale that allows any material to be aligned relative to any other.", "author_names": [ "Igor Vurgaftman", "Jerry R Meyer", "L R Ram-Mohan" ], "corpus_id": 121056857, "doc_id": "121056857", "n_citations": 5522, "n_key_citations": 105, "score": 0, "title": "Band parameters for III V compound semiconductors and their alloys", "venue": "", "year": 2001 }, { "abstract": "Contributors. Preface. Gallium Nitride (GaN) (V. Bougrov, et al. Aluminum Nitride (AIN) (Y. Goldberg) Indium Nitride (InN) (A. Zubrilov) Boron Nitride (BN) (S. Rumyantsev, et al. Silicon Carbide (SiC) (Y. Goldberg, et al. Silicon Germanium (Si 1 xGe x) (F. Schaffler) Appendix 1: Basic Physical Constants. Appendix 2: Periodic Table of the Elements. Appendix 3: Rectangular Coordinates for Hexagonal Crystal. Appendix 4: The First Brillouin Zone for Wurtzite Crystal. Appendix 5: Zinc Blende Structure. Appendix 6: The First Brillouin Zone for Zinc Blende Crystal. Additional References.", "author_names": [ "M E Levinshtein", "Sergey Rumyantsev", "Michael S Shur" ], "corpus_id": 136897631, "doc_id": "136897631", "n_citations": 1416, "n_key_citations": 52, "score": 0, "title": "Properties of advanced semiconductor materials GaN, AlN, InN, BN, SiC, SiGe", "venue": "", "year": 2001 }, { "abstract": "Silicon, germanium, and related alloys, which provide the leading materials platform of electronics, are extremely inefficient light emitters because of the indirect nature of their fundamental energy bandgap. This basic materials property has so far hindered the development of group IV photonic active devices, including diode lasers, thereby significantly limiting our ability to integrate electronic and photonic functionalities at the chip level. Here we show that Ge nanomembranes (i.e. single crystal sheets no more than a few tens of nanometers thick) can be used to overcome this materials limitation. Theoretical studies have predicted that tensile strain in Ge lowers the direct energy bandgap relative to the indirect one. We demonstrate that mechanically stressed nanomembranes allow for the introduction of sufficient biaxial tensile strain to transform Ge into a direct bandgap material with strongly enhanced light emission efficiency, capable of supporting population inversion as required for providing optical gain.", "author_names": [ "Jose R Sanchez-Perez", "Cicek Boztug", "Feng Chen", "Faisal F Sudradjat", "Deborah M Paskiewicz", "R B Jacobson", "Max G Lagally", "Roberto Paiella" ], "corpus_id": 25311288, "doc_id": "25311288", "n_citations": 193, "n_key_citations": 3, "score": 0, "title": "Direct bandgap light emitting germanium in tensilely strained nanomembranes", "venue": "Proceedings of the National Academy of Sciences", "year": 2011 }, { "abstract": "Semiconductor alloy nanowires with spatially graded compositions (and bandgaps) provide a new material platform for many new multifunctional optoelectronic devices, such as broadly tunable lasers, multispectral photodetectors, broad band light emitting diodes (LEDs) and high efficiency solar cells. In this review, we will summarize the recent progress on composition graded semiconductor alloy nanowires with bandgaps graded in a wide range. Depending on different growth methods and material systems, two typical nanowire composition grading approaches will be presented in detail, including composition graded alloy nanowires along a single substrate and those along single nanowires. Furthermore, selected examples of applications of these composition graded semiconductor nanowires will be presented and discussed, including tunable nanolasers, multi terminal on nanowire photodetectors, full spectrum solar cells, and white light LEDs. Finally, we will make some concluding remarks with future perspectives including opportunities and challenges in this research area.", "author_names": [ "Xiujuan Zhuang", "Cun-Zheng Ning", "Anlian Pan" ], "corpus_id": 205242437, "doc_id": "205242437", "n_citations": 86, "n_key_citations": 0, "score": 0, "title": "Composition and bandgap graded semiconductor alloy nanowires.", "venue": "Advanced materials", "year": 2012 }, { "abstract": "Abstract This paper presents simple but accurate closed form equations for Band Gap Narrowing (BGN) for n and p type, Si, Ge, GaAs and GexSi1 x alloys and strained layers. The equations are derived by identifying the four components of BGN: exchange energy shift of the majority band edge, correlation energy shift of the minority band edge and impurity interaction shifts of the two band edges. In the simple parabolic band approximation, the BGN is determined by the effective masses of the carriers and the relative permittivity of the semiconductor. For real semiconductors, known corrections due to anisotropy of the bands, due to multi valleys in a band and due to interactions between sub bands are used. The values of BGN for n Si, n Ge and n and p GaAs calculated using this simple formulation agree closely with the theoretical values calculated by other authors using advanced but complex many body methods and the Random Phase Approximation for screening effects. For p Si and p Ge ours appear to be the first calculations taking all interactions into account. Experimental values of BGN for all semiconductors except for p Ge for which no data could be found, are also in very good agreement with our theory. The Fermi level for n and p Si and p GaAs is determined using the published luminescence data. In heavily doped p type semiconductors, the values are found to be considerably smaller than those calculated using the known values of the effective density of states. The values of apparent BGN for n and p Si and p GaAs calculated using experimentally determined Fermi levels are in remarkably good agreement with the experimental values derived from device measurements. All results are presented in a form which lends itself to numerical computer simulation studies.", "author_names": [ "S C Jain", "David J Roulston" ], "corpus_id": 94170758, "doc_id": "94170758", "n_citations": 353, "n_key_citations": 9, "score": 0, "title": "A simple expression for band gap narrowing (BGN) in heavily doped Si, Ge, GaAs and GexSi1 x strained layers", "venue": "", "year": 1991 }, { "abstract": "In recent years, quantum dots have been successfully grown by self assembling processes. For optoelectronic device applications, the quantum dot structures have advantages such as reduced phonon scattering, longer carrier lifetime, and lower detector noise due to low dimensional confinement effect. Comparing to traditional optoelectronic III V and other materials, self assembled Ge quantum dots grown on Si substrates have a potential to be monolithically integrated with advanced Si based technology. In this paper, we describe the growth of self assembled, guided Ge quantum dots, and Ge quantum dot superlattices on Si. For dot growth, issues such as growth conditions and their effects on the dot morphology are reviewed. Then vertical correlation and dot morphology evolution are addressed in relation to the critical thickness of Ge quantum dot superlattices. In addition, we also discuss the quantum dot p i p photodetectors (QDIPs) and n i n photodetectors for mid infrared applications, and the quantum dot p i n photodetectors for 1.3 1.55 mum for communications applications. The wavelength of SiGe p i p QDIP can be tuned by the size as grown by various patterning methods. Photoresponse is demonstrated for an n i n structure in both the mid infrared and far infrared wavelength ranges. The p i n diodes exhibit low dark current and high quantum efficiency. The characteristics of fabricated light emitting diode (LED) devices are also discussed, and room temperature electroluminescence is observed for Ge quantum dot LED. The results indicate that Ge dot materials are potentially applicable for mid infrared (8 12 mum) detectors as well as fiber optic (1.3 1.55 mum) communications.", "author_names": [ "Kang L Wang", "Dongho Cha", "Jianlin Liu", "Christopher Chen" ], "corpus_id": 1526128, "doc_id": "1526128", "n_citations": 136, "n_key_citations": 0, "score": 0, "title": "Ge/Si Self Assembled Quantum Dots and Their Optoelectronic Device Applications", "venue": "Proceedings of the IEEE", "year": 2007 } ]

[ { "abstract": "Abstract: This chapter deals with high performance complementary metal oxide semiconductor (CMOS) image sensors. It starts with a reminder of the basic principles and sensor parameters for the detection of charged particles and photons, in particular high energy photons. It is then followed by two sections, the first one on charged particles and the second on the detection of X rays. In each section, first the main applications are introduced, then the history and state of art of CMOS image sensors in the field are presented. As in many of the applications, large area sensors are needed, some notes on the stitching process are also included. The chapter is concluded with a brief review of future trends as well as some suggestions for further reading.", "author_names": [ "Renato Turchetta" ], "corpus_id": 108225440, "doc_id": "108225440", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Complementary metal oxide semiconductor (CMOS) sensors for high performance scientific imaging", "venue": "", "year": 2014 }, { "abstract": "comprehensive database of thesis abstracts (Ph.D. Masters and MFA) on topics at the intersections between art, science and technology. This Englishlanguage database is hosted by Pomona College (Claremont, CA) In addition to being published in the database, a selection of abstracts chosen by a peer review panel for their special relevance will be published annually in Leonardo journal and on the Leonardo OnLine website. The deadline for receipt of abstracts for review by the LABS peer review panel is 30 June each year. Abstract rankings are announced in the autumn. Authors of abstracts most highly ranked by the panel are invited to submit an article for publication consideration in Leonardo. The aim of LABS is not to duplicate existing thesis databases but rather to give visibility to interdisciplinary work, which is often hard to retrieve from existing databases. The LABS Peer Review Panel for 2014 2015 consists of Yiannis Colakides, Tom Leeser, Emmanuel Mahe, Soraya Murray, Timothy Murray, Andrea Polli, Martin Reiser, Charissa N. Terranova and Iannis Zannos. To submit a thesis abstract or browse ones currently published in the English language database, visit: <http:/leonardolabs.pomona.edu>", "author_names": [ "Silvia Casini" ], "corpus_id": 57562176, "doc_id": "57562176", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "The Aesthetics of Magnetic Resonance Imaging (MRI) Setting MRI in Motion from the Scientific Laboratory to an Art Exhibition", "venue": "Leonardo", "year": 2015 }, { "abstract": "Abstract. Time resolved visualization of fast processes using high speed digital video cameras has been widely used in most fields of scientific research for over a decade. In many applications, high speed imaging is used not only to record the time history of a phenomenon but also to quantify it, hence requiring dependable equipment. Important aspects of two dimensional imaging instrumentation used to qualitatively or quantitatively assess fast moving scenes include sensitivity, linearity, as well as signal to noise ratio (SNR) Under certain circumstances, the weaknesses of commercially available high speed cameras, i.e. sensitivity, linearity, image lag, etc. render the experiment complicated and uncertain. Our study evaluated two advanced CMOS based, continuous recording, high speed cameras available at the moment of writing. Various parameters, potentially important toward accurate time resolved measurements and photonic quantification, have been measured under controlled conditions on the bench, using scientific instrumentation. Testing procedures to measure sensitivity, linearity, SNR, shutter accuracy, and image lag are proposed and detailed. The results of the tests, comparing the two high speed cameras under study, are also presented and discussed. Results show that, with careful implementation and understanding of their performance and limitations, these high speed cameras are reasonable alternatives to scientific CCD cameras, while also delivering time resolved imaging data.", "author_names": [ "Julien Manin", "Scott A Skeen", "Lyle M Pickett" ], "corpus_id": 128120998, "doc_id": "128120998", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Performance comparison of state of the art high speed video cameras for scientific applications", "venue": "", "year": 2018 }, { "abstract": "Abstract Nano graphene (Gr) particles are of abundant methodical and scientific interest as having the astonishing prospective to usage as the sensors element in the miniaturized and biomedical sensor device. The nano Gr particles have been appeared on the life science and health platform due to their interesting material performance like; excellent biocompatibility, conductivity, super para magnetism, thermal, chemical, mechanical and metallurgical properties to use as a sensor component. In recent years, Gr as nanoparticles has acquired powerful technological and scientific attention and having potential applications like; for fabrication of super capacitors, batteries, solar or fuel cells, miniaturized and biomedical sensors. Gr is one of the most influential nano composites with endowment of use in the sensing mechanism like; bio sensing, bio imaging and diagnostic of diseases due to stimulating material behavior like; biocompatibility, cell growing properties, excellent surface behavior thermally and chemically etc. The present discussion explores the state of art review and prospective of the Gr in the miniaturized and biomedical sensors. The sensing mechanism for each of the sensors has been discussed for betters understanding of the functionality and prospective of the Gr in the sensors.", "author_names": [ "Ranvijay Kumar", "Rupinder Singh", "David Hui", "Luciano Feo", "Fernando Fraternali" ], "corpus_id": 139729469, "doc_id": "139729469", "n_citations": 95, "n_key_citations": 0, "score": 0, "title": "Graphene as biomedical sensing element: State of art review and potential engineering applications", "venue": "", "year": 2018 }, { "abstract": "Abstract Recent developments in seismic acquisition systems and seismic data visualization have contributed to improve the imaging of seismic geomorphologies over a broad range of topics. This study focuses on a new high resolution P Cable 3D seismic cube located in the Hoop area in the SW Barents Sea. The scientific motivations of the study are (1) to document glacial landforms on a meter scale, (2) to study the link of these landforms with the subsurface, and (3) to understand ice stream dynamics by detailed interpretation of main horizons, including the seabed, intra glacial horizons, and Upper Regional Unconformity (URU) The horizons are assessed using the concept of seismic geomorphology, and compared with interpretations derived from conventional 3D seismic and state of the art multibeam echosounder technologies to discuss the benefits and limitations of the different geophysical technologies. A well defined intra glacial seismic reflection is imaged in the eastern part of the P Cable cube. This reflection has an overall NE trending ridge shaped morphology, which is up to 50 m high and 5 10 km wide, and interpreted as a shear margin moraine. The top of the moraine displays well defined iceberg ploughmarks and clear slope failure events along its eastern flank. The seabed geomorphology, which has been directly shaped by glacial processes related to multiple phases of ice streaming, appears to be influenced by the buried shear margin moraine. Mega scale glacial lineations (MSGLs) indicative of fast flowing ice streams characterize the seabed west of the moraine. Infilled MSGLs and different sets of iceberg ploughmarks with large berms dominate the seabed geomorphology above the moraine. The seabed east of the moraine, characterized by a smooth morphology and few pockmarks, is inferred to reflect more slowly moving ice. Not resolved by other geophysical techniques, seismic attribute maps of P Cable 3D allowed the identification of smaller ploughmarks and corrugated ridges related to paleo tides. Eroded by the larger iceberg ploughmarks, these small ploughmarks are suggested to be linked to an earlier rapid disintegration of the Barents Sea Ice Stream. The new high resolution 3D seismic data have led to the development of a revised ice stream model of the Barents Sea, linking the glacial deposits to different ice stream events.", "author_names": [ "Benjamin Bellwald", "Sverre Planke", "Emilia D Piasecka", "Michael Alex Matar", "K Andreassen" ], "corpus_id": 135029478, "doc_id": "135029478", "n_citations": 16, "n_key_citations": 1, "score": 0, "title": "Ice stream dynamics of the SW Barents Sea revealed by high resolution 3D seismic imaging of glacial deposits in the Hoop area", "venue": "", "year": 2018 }, { "abstract": "Abstract Oral mucosal diseases are common health problems that reduce overall wellbeing and increase the risk for several systemic diseases. Due to the limitations of present diagnostics, new non invasive methods are needed for reliable, affordable, real time screening and follow up of oral mucosal lesions. Bioimpedance spectroscopy, spectral camera imaging and other optical methods are promising novel techniques to detect abnormal changes in oral mucosa. In this review, the current status of bioimpedance spectroscopy and autofluorescence utilising spectral camera techniques in the assessment of oral mucosal health is critically evaluated. Scientific publications related to bioimpedance spectroscopy were surveyed using PubMed and Scopus databases. Search was done using a combination of terms \"oral mucosa\" \"oral cancer\" \"squamous cell cancer\" \"tissue\" \"electrical impedance measurement\" and \"bioimpedance spectroscopy\" Publications related to spectral cameras were searched from PubMed with a focus on autofluorescence utilising spectral camera techniques. Search was done using terms \"autofluorescence\" \"oral disease\" and \"VELscope\" publication date restricted from 2008 to date. In this review, we also discuss the future trends and strategies such as combining different methods, e.g. spectral cameras and bioimpedance spectroscopy that could represent a unique multimodality in vivo tool for providing complementary information on the health status of the oral mucosa.", "author_names": [ "Shekh Emran", "Miia Hurskainen", "Laura Tomppo", "Reijo Lappalainen", "Arja M Kullaa", "Sami Myllymaa" ], "corpus_id": 208498112, "doc_id": "208498112", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Bioimpedance spectroscopy and spectral camera techniques in detection of oral mucosal diseases: a narrative review of the state of the art", "venue": "Journal of medical engineering technology", "year": 2019 }, { "abstract": "Author(s) Gamache, Raymond Advisor(s) Jung, Michael E Abstract: This dissertation describes how modern organic chemistry can be used to improve and advance the field of molecular imaging, particularly in the realm of positron emission tomography (PET) imaging. Organic chemistry is an interdisciplinary art that is featured in many scientific disciplines to advance problem solving capabilities. Herein, I report how chemical methods developed in our laboratory have expanded the scope of available labeling technologies for molecular imaging applications. Additionally, we designed a bifunctional chemical linker to produce a dual modality (optical/PET) imaging tracer and investigated its physicochemical properties in vivo. Chapter One reviews the procedures developed in organic chemistry that have been of particular importance to PET and fluorescence imaging. The topics covered in detail are fluorine 18 chemical methodologies, bioorthogonal chemistry, and multi functional chemical linkers used in antibody imaging systems.Chapter Two describes the development of a regiospecific copper mediated oxidative fluorination methodology that is compatible with aryl stannanes. This methodology tolerates nucleophilic functionalities, uses a recyclable fluorine source and proceeds under mild conditions (60 oC, 3.2h) In addition to nucleophilic groups, the procedure allows for the fluorination of heteroaryl rings and bioactive molecules, such as estrone.Chapter Three demonstrates the creation of an ambiphilic cyclopentadiene that can be used as a bioorthogonal reagent. The diene undergoes fast reaction rates with multiple dienophiles already being used in bioorthogonal applications. Practical applications of this new bioorthogonal ligation are highlighted via fluorescence labeling of a commercial neuropeptide.Chapter Four discloses the synthesis of a series of multi modal imaging linkers used in the molecular imaging of prostate specific cell antigen (PSCA) expressing tumors. These linkers were conjugated to engineered antibody fragments that target PSCA and allow for dual PET and optical imaging. The PET imaging portion allows for whole body PET scans to obtain tumor localization and metastasis information while the optical portion facilitates intra operative removal of tumor tissue through fluorescence guided surgery.", "author_names": [ "Raymond F Gamache" ], "corpus_id": 228557556, "doc_id": "228557556", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Organic Chemistry Methods Towards the Development of Molecular Imaging Tracers", "venue": "", "year": 2018 }, { "abstract": "Abstract With the increased availability of very high resolution satellite imagery, terrain based imaging and participatory sensing, inexpensive platforms, and advanced information and communication technologies, the application of imagery is now ubiquitous, playing an important role in many aspects of life and work today. As a leading organisation in this field, the International Society for Photogrammetry and Remote Sensing (ISPRS) has been devoted to effectively and efficiently obtaining and utilising information from imagery since its foundation in the year 1910. This paper examines the significant challenges currently facing ISPRS and its communities, such as providing high quality information, enabling advanced geospatial computing, and supporting collaborative problem solving. The state of the art in ISPRS related research and development is reviewed and the trends and topics for future work are identified. By providing an overarching scientific vision and research agenda, we hope to call on and mobilise all ISPRS scientists, practitioners and other stakeholders to continue improving our understanding and capacity on information from imagery and to deliver advanced geospatial knowledge that enables humankind to better deal with the challenges ahead, posed for example by global change, ubiquitous sensing, and a demand for real time information generation.", "author_names": [ "Jun Chen", "Ian J Dowman", "Songnian Li", "Zhilin Li", "Marguerite Madden", "Jon P Mills", "Nicolas Paparoditis", "Franz Rottensteiner", "Monika Sester", "Charles K Toth", "John C Trinder", "Christian Heipke" ], "corpus_id": 59437051, "doc_id": "59437051", "n_citations": 73, "n_key_citations": 3, "score": 0, "title": "Information from imagery: ISPRS scientific vision and research agenda", "venue": "", "year": 2016 }, { "abstract": "Abstract Developments in digital methods of rock art study in Western Europe have considerably diversified and enriched this field of research in the last 25 years. This is especially the case for microanalyses of artistic materials (datings, pigment characterization, etc. and also for the study of the images themselves, their topography, their positioning and their contexts. 3D analyses, software with colorimetric filters, and macro microscopic imaging represent examples of promising new tools for the study of rock art. The object of this article is to show some of these tools' applications in the context of decorated caves through specific cases taken from the study of several caves in France: Blanchard (Indre) Les Gorges (Jura) Rouffignac and especially Les Bernoux (Dordogne) The contributions of several applied techniques highlight the importance of their use in combination. This includes first of all photography, and multiple scientific applications of digital photographs such as photogrammetry, macrophotography and decorrelation stretch (colorimetric treatment) This article provides a synthesis of different results, in order to show the potential of these methods, especially for their use in combination. We emphasize in particular the contribution of decorrelation stretch, used to enhance the reading of color and pigments.", "author_names": [ "Eric Robert", "Stephane Petrognani", "Emilie Lesvignes" ], "corpus_id": 131845291, "doc_id": "131845291", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Applications of digital photography in the study of Paleolithic cave art", "venue": "", "year": 2016 }, { "abstract": "Abstract Scientific analysis of panel paintings could provide key information to art historians and conservators about the composition and condition of the constituent layers. Knowledge of the structure, stratigraphy, and condition of the subsurface layers of these objects is highly relevant to conservation measures, when stability problems such as delamination or internal cracking are considered. Terahertz time domain imaging (THz TDI) in reflection geometry is capable of highlighting interfaces between layers in a stratigraphic buildup, and thus makes structural information available in the form of subsurface 3D images and stratigraphic images (B scans) The technique is contactless and non invasive, and has been successfully applied to investigation of panel paintings. Regarding gilded panel paintings, the extremely high reflectivity of metals at submillimeter wavelengths generally precludes the transmission of electromagnetic waves through metallic films. Therefore, imaging of subsurface features below gilded finishes may be regarded as Very challenging. A small but non negligible direct transmission through metal films occurs if the film thickness is of the order of the skin depth of the metal in the terahertz range, due to the skin effect. The thickness of gold leaf, a fraction of a micrometer, matches the skin depth of gold in the terahertz frequency range covered by THz TDI devices. We therefore investigated and imaged subsurface features of panel paintings through gilded finishes with THz TDI. Subsurface layers of three gilded panel paintings (two contemporary tempera panel replicas and one fourteenth century icon) have been successfully imaged behind gold finishes with THz TDI.", "author_names": [ "Corinna Ludovica Koch Dandolo", "Antonino Cosentino", "Peter Uhd Jepsen" ], "corpus_id": 55215890, "doc_id": "55215890", "n_citations": 15, "n_key_citations": 2, "score": 0, "title": "Inspection of panel paintings beneath gilded finishes using terahertz time domain imaging", "venue": "", "year": 2015 } ]

[ { "abstract": "Abstract Cu2O is widely investigated in field of lithium ion battery and electric ignition semiconductor ceramic material. By considering the higher thermal stability, Cu2O is first designed as cathode for thermal battery in this paper. The discharging behavior of Cu2O with average diameter of 0.3 mm at 500 degC presents excellent specific capacity above 260 mAh*g 1 under the current density of 0.2 A cm 2 with cut off voltage of 1.73 V, which is much better than the commercial thermal battery cathodes such as FeS2 and CoS2. By analyzing the Li/Cu2O cells electrochemical behavior and characters at different discharge stages, the possible discharge reactions of Cu2O at high temperatures can be divided into three steps: 1) 3Cu2O Li LiCu3O3 3Cu; 2) LiCu3O3 2Li 3LiCuO; 3) LiCuO Li Li2O Cu, respectively. With the increase of Cu2O grain size, the reaction time of first step is prolonged, and the specific capacity reduces from 260 mAh*g 1 to 191 mAh*g 1. This work provides a beginning for further study of Cu2O as a promising cathode material for thermal battery with high specific capacity and excellent thermal stability.", "author_names": [ "Zeshunji Luo", "Licai Fu", "Jiajun Zhu", "Wulin Yang", "De-yi Li", "Ling-ping Zhou" ], "corpus_id": 214022723, "doc_id": "214022723", "n_citations": 15, "n_key_citations": 1, "score": 1, "title": "Cu2O as a promising cathode with high specific capacity for thermal battery", "venue": "", "year": 2020 }, { "abstract": "Abstract Air humidity assisted sorption thermal battery has attracted increasing interests throughout the world for its strong ability to capture atmospheric moisture and the related heating effects. However, the controllable stable output temperature is still unrealized, which hinders the application potential. Here we discover the phenomenon of \"reaction wave\" happening in the sorption reactor for the first time and accordingly build a \"reaction wave\" model which sheds light on the mechanism for receiving stable output and provides design criterion for obtaining stable output. To further increase the storage density of sorption thermal battery, we put forward a design strategy of \"dual reactor\" and establish a 1.3 kWh proof of concept prototype, which is able to warm up air from 20 degC to 38.1 degC for 5.51 h, and obtain a storage density of 240 kWh/m3 higher than that of previous publications. Therefore, \"Reaction wave\" model is expected to guide sorbent selection and reactor design.", "author_names": [ "Yannan Zhang", "Haohui Dong", "Ruzhu Wang", "Penghui Feng" ], "corpus_id": 214340594, "doc_id": "214340594", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Air humidity assisted sorption thermal battery governed by reaction wave model", "venue": "", "year": 2020 }, { "abstract": "Metal hydrides have demonstrated ideal physical properties to be the next generation of thermal batteries for solar thermal power plants. Previous studies have demonstrated that they already operate at the required operational temperature and offer greater energy densities than existing technology. Thermal batteries using metal hydrides need to store hydrogen gas released during charging, and so far, practical demonstrations have employed volumetric storage of gas. This practical study utilises a low temperature metal hydride, titanium manganese hydride (TiMn1.5Hx) to store hydrogen gas, whilst magnesium iron hydride (Mg2FeH6) is used as a high temperature thermal battery. The coupled system is able to achieve consistent energy storage and release cycles. With titanium manganese hydride operating at ambient temperature (20 degC) Mg2FeH6 has to operate between ~350 degC and ~500 degC to counteract the pressure hysteresis displayed by TiMn1.5 between hydrogen uptake and release. The results attest the high susceptibility of both materials to thermal issues, such as a requirement for large temperature offsets, in order for the battery to achieve full cycling capacity. An energy density of 1488 kJ kg 1 was experimentally attained for 40 g of Mg2FeH6 with a maximum operating temperature around 520 degC.", "author_names": [ "Lucas Poupin", "Terry D Humphries", "Mark Paskevicius", "Craig E Buckley" ], "corpus_id": 210244322, "doc_id": "210244322", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "An experimental high temperature thermal battery coupled to a low temperature metal hydride for solar thermal energy storage", "venue": "", "year": 2020 }, { "abstract": "Abstract We perform heat transfer analysis of a thermal battery module for a high power and large capacity thermal battery system based on a detailed thermal model as well as an effective thermal model. Firstly, the transient thermal behavior of a small scale thermal battery module consisting of 13 stacks of unit cells is investigated by the detailed thermal model that considers every components. We show that the net effect of Joule heating (exothermic) and chemical reaction heat (endothermic) occurring in the unit cell result in different degree of cooling down the thermal battery depending on the operating condition. It is also found that anisotropic heat conduction due to the stacked geometry of the unit cell causes temperature non uniformity within the thermal battery module. Secondly, we also develop an effective thermal model based on the properly averaged thermophysical properties of constituent materials of unit cells as well as the homogenized heat sources. The effective thermal model is validated by comparing it with the detailed thermal model for the small scale thermal battery module consisting of 13 stacks of unit cells, and it is further extended to the large scale thermal battery module consisting of 54 stacks of unit cells.", "author_names": [ "Mun Goung Jeong", "Jang-Hyeon Cho", "Bong Jae Lee" ], "corpus_id": 133169829, "doc_id": "133169829", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Heat transfer analysis of a high power and large capacity thermal battery and investigation of effective thermal model", "venue": "Journal of Power Sources", "year": 2019 }, { "abstract": "Abstract This study aims to analyze the thermal performance of the passive thermal management system (TMS) of the 18,650 lithium ion battery with application of phase change materials (PCM) To improve performance of TMS, nanoparticles, fins and porous metal foam are used beside the PCM, and their effects on the system performance are compared. The local thermal non equilibrium (LTNE) model and non Darcy law are considered to simulate the nano PCM melting inside the porous media. Numerical results are validated through previously published experimental data and results are presented for two, 4.6 W and 9.2 W, heat generation rates. Sole effects of adding nanoparticles to the PCM, utilizing different numbers of fins, and application of the metal foam on the system performance are scrutinized. Results indicated that the porous PCM composition performs more efficiently than the nano PCM and the fin PCM ones. In addition, DTavg, battery parameter is introduced and its variations are analyzed to judge about the effect of each technique to reduce the battery mean temperature. Using the porous PCM led to 4 6 K reduction in the battery mean temperature with respect to the pure PCM. Moreover, for the porous PCM composition a delay is observed in the PCM melting initiation time that can adversely affect the performance of battery TMS.", "author_names": [ "Mohammad Mahdi Heyhat", "S M Ali Mousavi", "Majid Siavashi" ], "corpus_id": 213821396, "doc_id": "213821396", "n_citations": 58, "n_key_citations": 0, "score": 0, "title": "Battery thermal management with thermal energy storage composites of PCM, metal foam, fin and nanoparticle", "venue": "", "year": 2020 }, { "abstract": "Since thermal energy generated by air conditionings (ACs) can be stored in the buildings providing the potential of shifting electricity consumption between different time periods, ACs are considered as an important demand response (DR) resource and attract extensive attentions. In order to achieve the compatibility of the inverter ACs with the current dispatch models, this paper attempts to model an inverter AC system as a thermal battery (TB) The comparisons between the TB and the lithium ion battery are given. In order to protect the end users' privacy and relieve the computational burden of the centralized control, a hierarchical control framework is designed and an aggregated TB model is proposed to handle the heterogeneity of the inverter ACs. A finite horizon optimization model is used to compare the operating performances of the aggregated TBs and the lithium ion batteries. Simulation results demonstrate that the aggregated TB model works well with the power dispatch model developed for the lithium ion batteries. In other words, with the TB modeling of ACs, lithium ion batteries can be replaced in current dispatch models providing service for the grid.", "author_names": [ "Meng Song", "Ciwei Gao", "Huaguang Yan", "Jianlin Yang" ], "corpus_id": 53046070, "doc_id": "53046070", "n_citations": 70, "n_key_citations": 9, "score": 0, "title": "Thermal Battery Modeling of Inverter Air Conditioning for Demand Response", "venue": "IEEE Transactions on Smart Grid", "year": 2018 }, { "abstract": "Abstract To satisfy the hot water demand of any building, a suitable thermal storage device must be added to a Photovoltaic thermal system (PVT) to address the time lag between the supply and demand of thermal energy. In this study, a nanofluid cooled photovoltaic/thermal system retrofitted with a phase change material (PCM) based thermal battery is designed to meet a portion of the electrical and thermal demands of a residential building for the climate of Dhahran, Saudi Arabia. Daily and yearly performance evaluation of the system is analytically performed through Engineering Equation Solver (EES) software and compared with the performances of a nanofluid cooled PVT system without thermal storage and an uncooled PV system together with an economic assessment of the proposed system. A comparison of systems with and without thermal storage shows that the introduction of a PCM thermal battery has made it possible to meet some of the building's thermal load but at the cost of reduction in the system's electrical and thermal outputs. The proposed system, however, shows an 11.7% improvement in its electrical performance over an uncooled PV system. The addition of thermal storage has made it possible to cover up to 27.3% of the residential thermal load along with 77% of the residential electrical load.", "author_names": [ "Muhammad O Lari", "Ahmet Z Sahin" ], "corpus_id": 116414371, "doc_id": "116414371", "n_citations": 32, "n_key_citations": 0, "score": 0, "title": "Effect of retrofitting a silver/water nanofluid based photovoltaic/thermal (PV/T) system with a PCM thermal battery for residential applications", "venue": "", "year": 2018 }, { "abstract": "Abstract Three different kinds of hierarchical MoS2 microspheres are successfully synthesized by a simple hydrothermal route, and their morphology, thermal stability and electrochemical performance in thermal battery are characterized. The flower like porous MoS2 microsphere with good crystallinity consists of MoS2 nano sheets with thickness of about 10 nm. Its evolution process is proposed, and includes three stages: a nucleus growth process following the principle of Ostwald ripening, MoS2 nano sheets growth and self assembly. The dependence of the macroscopic electrochemical properties on the microscopic structure and morphology is discussed. Since the MoS2 with flower like porous microsphere structure presents less weight loss, higher decomposition temperature, outstanding thermal stability and excellent compatibility with electrolyte, it performs longer discharge time and larger capacity when used as the cathode in the thermal battery, compared to MoS2 with other structures, FeS2 or CoS2. The possible discharge mechanism of MoS2 is proposed, and it can be divided into three steps, which are the generation of intercalation compounds containing lithium ions (LiXMoS2) desulfurization generating low valent intercalation compound and reduction from low valent intercalation compound to Mo, respectively.", "author_names": [ "Zheng Xiaodi", "Yan-li Zhu", "Yalun Sun", "Qing-jie Jiao" ], "corpus_id": 103896180, "doc_id": "103896180", "n_citations": 28, "n_key_citations": 0, "score": 0, "title": "Hydrothermal synthesis of MoS2 with different morphology and its performance in thermal battery", "venue": "", "year": 2018 }, { "abstract": "Nanocrystallization is widely used to improve the discharge performances of LIBs. While its lower thermal stability limits the operating time, especially for the thermal battery system, which discharges at high temperatures (usually 500 550 degC) In this paper, NiS2 particles were coated with amorphous carbon. Then they accumulated into submicron particles and were connected/fixed by a carbon network. The initial decomposition temperature of nano NiS2 increased from 400 degC to 590 degC after this hierarchical carbon modification. The hierarchical carbon modified nano NiS2 cathode revealed excellent discharge performances in thermal batteries at high temperatures. Specifically with 0.1 A cm 2 at 500 degC, the specific capacity and energy reach 610 mA h g 1 and 1082 W h kg 1, respectively, at a cut off voltage of 1.4 V. The specific energy retains about 503 W h kg 1 even at 700 degC. The multiple protective effects of hierarchical carbon modification not only effectively improve the conductivity and thermal stability, but also inhibit the dissolution and shuttling of products. So, hierarchical carbon modification makes nano NiS2 more suitable for high specific energy and long operating life thermal batteries.", "author_names": [ "Chuanyu Jin", "Licai Fu", "Jiajun Zhu", "Wulin Yang", "De-yi Li", "Ling-ping Zhou" ], "corpus_id": 102879516, "doc_id": "102879516", "n_citations": 19, "n_key_citations": 0, "score": 0, "title": "A hierarchical carbon modified nano NiS2 cathode with high thermal stability for a high energy thermal battery", "venue": "", "year": 2018 }, { "abstract": "Abstract The design of effective thermal batteries with phase change materials (PCM) relies on the addition of materials with high thermal conductivity and specific surface area to increase the rate of thermal charging and discharging. This paper is a comparative study between two such enhancement materials, namely aluminum and graphite foams, saturated with phase change material. The rate of heat charging was measured for samples exposed to a constant heat flux boundary condition. The impact of aluminum foam was investigated as a function of PCM viscosity, heat flux magnitude, and aluminum pore density. The influence of graphite foam was considered by varying the heat flux magnitude and graphite bulk density. By using a standard experimental configuration, thermal charging enhancement of the foams was compared based on four metrics: composite latent heat, thermal conductivity, time to end of melt, and junction temperature between the heater and the sample. To relate all metrics, two dimensionless parameters were defined to compare diffusive transport and energy storage to junction temperature. It was shown that the thermal charging enhancement of graphite foams is superior to that of aluminum foams based on these performance metrics due to high thermal conductivity, low density, and small pore size.", "author_names": [ "Anne Mallow", "Omar A Abdelaziz", "Samuel Graham" ], "corpus_id": 125831110, "doc_id": "125831110", "n_citations": 29, "n_key_citations": 0, "score": 0, "title": "Thermal charging performance of enhanced phase change material composites for thermal battery design", "venue": "", "year": 2018 } ]

[ { "abstract": "While the semiconductor industry has provided us with powerful systems for personal supercomputing, how to efficiently harness the computing power of these systems still remains a major unsolved problem. This challenge must be approached by simultaneously solving the synchronization problem and the parallel programmability problem. This paper reviews the synchronization issues in modern parallel computer architectures, surveys the state of the art approaches used to alleviate these problems, and proposes our Request Store Forward (RSF) model of synchronization. This model splits the atomic synchronization operations into two phases, thus freeing the processing elements from polling operations. Finally, we show how we could learn from nature and improve the overall system performance by closely coupling peripheral computing units and functional units.", "author_names": [ "Shaoshan Liu", "Jean-Luc Gaudiot" ], "corpus_id": 39601897, "doc_id": "39601897", "n_citations": 16, "n_key_citations": 2, "score": 1, "title": "Synchronization Mechanisms on Modern Multi core Architectures", "venue": "Asia Pacific Computer Systems Architecture Conference", "year": 2007 }, { "abstract": "The goal of this paper is to review some of the several approaches that have been proposed in recent years to address the synchronization problems in both multiprocessor and the multi core processor. Here also propose some synchronization model to address the challenges faced by synchronization mechanisms on modern parallel computing architectures. Shared memory multiprocessors are frequently used as compute servers with multiple parallel applications executing at the same time. In such environments, the efficiency of a parallel application can be significantly affected by the operating system scheduling policy. In this paper, we use detailed simulation studies to evaluate the performance of several different scheduling strategies, these include regular priority scheduling, co scheduling or gang scheduling, process control with processor partitioning, handoff scheduling, and affinity based scheduling. We also explore tradeoffs between the use of busy waiting and blocking synchronization primitives and their interactions with the scheduling strategies.", "author_names": [ "M Rahman" ], "corpus_id": 8134329, "doc_id": "8134329", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Process synchronization in multiprocessor and multi core processor", "venue": "2012 International Conference on Informatics, Electronics Vision (ICIEV)", "year": 2012 }, { "abstract": "The use of efficient synchronization mechanisms is crucial for implementing fine grained parallel programs on modern shared cache multi core architectures. In this paper we study this problem by considering Single Producer/Single Consumer (SPSC) coordination using unbounded queues. A novel unbounded SPSC algorithm capable of reducing the row synchronization latency and speeding up Producer Consumer coordination is presented. The algorithm has been extensively tested on a shared cache multi core platform and a sketch proof of correctness is presented. The queues proposed have been used as basic building blocks to implement the FastFlow parallel framework, which has been demonstrated to offer very good performance for fine grain parallel applications.", "author_names": [ "Marco Aldinucci", "Marco Danelutto", "Peter Kilpatrick", "Massimiliano Meneghin", "Massimo Torquati" ], "corpus_id": 30105454, "doc_id": "30105454", "n_citations": 60, "n_key_citations": 5, "score": 0, "title": "An Efficient Unbounded Lock Free Queue for Multi core Systems", "venue": "Euro Par", "year": 2012 }, { "abstract": "The use of efficient synchronization mechanisms is crucial for implementing fine grained parallel programs on modern shared cache multi core architectures. In this paper we study this problem by considering Single Producer/Single Consumer (SPSC) coordination using unbounded queues. A novel unbounded SPSC algorithm capable of reducing the row synchronization latency and speeding up Producer Consumer coordination is presented. The algorithm has been proven correctand extensively tested on a shared cache multi core platform. The queues proposed have been used as basic building blocks to implement the FastFlow parallel framework, which has been demonstrated to offer very good performance for fine grain parallel applications.", "author_names": [ "Marco Aldinucci", "Marco Danelutto", "Peter Kilpatrick", "Massimiliano Meneghin", "Massimo Torquati" ], "corpus_id": 18727614, "doc_id": "18727614", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "An Efficient Synchronisation Mechanism for Multi Core Systems", "venue": "", "year": 2012 }, { "abstract": "Although Ant Colony Systems (ACS) have gained much attention in last two decades but slow execution and convergence speed are still two challenges for these metaheuristic algorithms. Many parallel implementations have been proposed for faster execution. However, most of available implementations use coarse grained synchronization mechanisms that are not efficient and scalable. In this work, we have taken a fine grained (ant level) approach that is more efficient and scalable. We have used traveling salesman problem as a test case and have presented a parallel finegrained implementation for shared memory multi core systems. Our experimental results show that our proposed parallel implementation can achieve considerably higher speedup values on modern multicore processors. General Terms Optimization, Parallel Processing.", "author_names": [ "Ali Hadian", "Saeed Shahrivari", "Behrouz Minaei-Bidgoli" ], "corpus_id": 12449474, "doc_id": "12449474", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Fine grained Parallel Ant Colony System for Shared Memory Architectures", "venue": "", "year": 2012 }, { "abstract": "Whether to use multiple threads in one process (MPI+X) or multiple processes (pure MPI) has long been an important question in HPC. Techniques like in situ analysis and visualization further complicate matters, as it may be very difficult to couple the different components in a way that would allow them to run in the same process. Combined with the growing interest in task based programming models, which often rely on fine grained tasks and synchronization, a question arises: Is it possible to run two tightly coupled task based applications in two separate processes efficiently or do they have to be combined into one application? Through a range of experiments on the latest Intel Xeon Scalable (Skylake) and AMD EPYC (Zen) many core architectures, we have compared performance of fine grained synchronization and data exchange between threads in the same process and threads in two different processes. Our experiments show that although there may be a small price to pay for having two processes, it is still possible to achieve very good performance. The key factors are utilizing shared memory, selecting the right thread affinity, and carefully selecting the way the processes are synchronized.", "author_names": [ "Jiri Dokulil", "Siegfried Benkner" ], "corpus_id": 184482687, "doc_id": "184482687", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Exploring the Performance of Fine Grained Synchronization and Data Exchange Across Process Boundaries on Modern Multi core Architectures", "venue": "ICCS", "year": 2019 }, { "abstract": "In this paper, we propose a new approach for the predictability and optimality of the inter core communication and execution of tasks allocated on different cores of multicore architectures. Our approach is based on the execution of synchronous programs written in the ForeC programming language on deterministic architectures called PREcision Timed. The originality of the work resides in the time triggered model of computation and communication that allows for a very precise control over the thread execution. Synchronization is done via configurable Time Division Multiple Access (TDMA) arbitrations where the optimal size and offset of the time slots are computed to reduce the inter core synchronization costs. We implemented a robotic application and simulated it using MORSE, a robotic simulation environment. Results show that the model we propose guarantees time predictable inter core communication, the absence of concurrent accesses (without relying on hardware mechanisms) and allows for optimized execution throughput.", "author_names": [ "Nicolas Hili", "Alain Girault", "Eric Jenn" ], "corpus_id": 204701443, "doc_id": "204701443", "n_citations": 1, "n_key_citations": 1, "score": 0, "title": "Worst Case Reaction Time Optimization on Deterministic Multi Core Architectures with Synchronous Languages", "venue": "2019 IEEE 25th International Conference on Embedded and Real Time Computing Systems and Applications (RTCSA)", "year": 2019 }, { "abstract": "Ever since mass market processors transitioned from single core to multi core architectures, software could no longer rely on an increase in sequential performance for an increase in software performance. Now, developing high performance software on multi core architectures requires to exploit the apparent parallelism. Concurrent programming is the main tool for developing such software, but programmers struggle to create correct and scalable concurrent systems. It is argued in this thesis Communicating Sequential Processes (CSP) is a great model for creating correct and expressive concurrent systems. Further, it is argued combining the parallel nature of CSP with a dynamic multithreaded runtime system sets the foundation for creating high performant and scalable software for multicore architectures. This thesis details the development of ProXC+ a CSP influenced concurrency library for modern C+ which is built around dynamic multithreading. Dynamic multithreading is implemented as a collection of lightweight processes cooperatively scheduled on multiple schedulers. The runtime system follows the hybrid threading model, where processes are implemented as user threads, and each runtime scheduler runs on its own kernel thread. Runtime schedulers employ randomized work stealing for load balancing ready processes to idle schedulers. A detailed design and implementation of ProXC+ is presented, with focus on dynamic multithreading. New and existing algorithms are described, mostly for how process management, inter process communication and synchronization is administered by the runtime schedulers. A series of benchmarks with various degrees of parallelism is performed. ProXC+ yields promising performance results, however some issues with the work stealing algorithm are highlighted and discussed. ProXC+ is concluded as a successful project, providing expressive and correct abstractions for creating concurrent programs and is able to exploit the parallelism in multi core architectures. Some potential candidates for future work is outlined, including implementing support for networking. The ProXC+ library is publicly released as an open source project with an MIT license, available free of charge on GitHub.", "author_names": [ "Edvard Severin Pettersen" ], "corpus_id": 67203148, "doc_id": "67203148", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "ProXC+ A CSP inspired Concurrency Library for Modern C+ with Dynamic Multithreading for Multi Core Architectures", "venue": "", "year": 2017 }, { "abstract": "Abstract Modern processors contain several specific hardware modules and multiple cores to ensure performance for a wide range of applications. In this context, FPGAs are frequently used as the implementation platform, since they offer architecture customization and fast time to market. However, many of them may not have the needed resources to implement all the necessary features, because of costs or complexity of the system to be implemented. When some needed functionalities do not fit in the target, they must be mapped into the much slower software domain. In this work, we exploit the fact these designs usually underuse their available BRAMs and propose a low cost hardware based function reuse mechanism for FPGAs, recovering some of the performance lost from the software part of applications that could not be implemented in hardware logic, with minimal impact on LUT usage. This is achieved by saving the inputs and outputs of the most frequently executed functions in a BRAM based reuse table, so the next function executions with the same arguments can be skipped. This mechanism supports both precise and approximate modes and is evaluated with a 4 issue VLIW processor implemented in HDL, also considering a multi core environment. Precise reuse, in single and multi core scenarios, is assessed by running applications that use a software library to emulate floating point operations. Approximate reuse is evaluated over a single core image processing application that tolerates a certain level of error. Our scheme achieves 1.39 x geomean speedup in the precise single core, while the multi core case demonstrates application improvements from 1.25 x to 1.9 x when we start sharing the reuse table. In the approximate scenario, we achieve 1.52 x speedup with less than 10% error.", "author_names": [ "Pedro Henrique Exenberger Becker", "Anderson Luiz Sartor", "Marcelo Brandalero", "A C S Beck" ], "corpus_id": 53280917, "doc_id": "53280917", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "BRAM based function reuse for multi core architectures in FPGAs", "venue": "Microprocess. Microsystems", "year": 2018 }, { "abstract": "Modern high performance server systems are typically built as several multi core chips put together in a single system. Each chip is connected to its local memory via an integrated memory controller (IMC) behaving as a node and hence the single machine behaving as non uniform memory architecture (NUMA) Various user level run time systems adapt work stealing load balancing technique in multi core processors. The work stealing run times have to be aware of the topology of the processor on which they are running. Work stealing run times on multi core processors typically rely on lock based synchronization to guarantee the coherency of shared mutable state. Synchronization constructs such as mutex locks, condition variables, and barriers are extensively used in implementation of these user level work stealing run times. The locality of these lock variables in multi socket NUMA processors has considerable impact on the performance of these run time systems. This paper studies the effect of locality of these synchronization constructs and proposes NUMA awareness to them. The proposed methodology is implemented using a source to source translator of OpenMP run time, evaluated using OpenMP microbenchmark programs.", "author_names": [ "B Vikranth", "Rajeev Wankar", "C Raghavendra Rao" ], "corpus_id": 65999258, "doc_id": "65999258", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Affinity Aware Synchronization in Work Stealing Run Times for NUMA Multi core Processors", "venue": "", "year": 2019 } ]

[ { "abstract": "Photonic crystals (PhCs) are optical materials which can affect the propagation of light in multiple ways. In recent years PhCs contributed to major technological developments in the field of semiconductor lasers, light emitting diodes and photovoltaic applications. In our case we are investigating the capabilities of photonic crystal slabs with the aim to improve the performance of heavy inorganic scintillators. To study the combination of scintillators and PhCs we use a Monte Carlo program to simulate the light propagation inside a scintillator and a rigorous coupled wave analysis (RCWA) framework to analyse the optical PhC properties. The simulations show light output improvements of a wide range of scintillating materials due to light scattering effects of the PhC slabs. First samples have been produced on top of 1.2 x 2.6 x 5 mm LSO (cerium doped Lutetium Oxyorthosilicate, Lu2SiO5:Ce3+ scintillators using electron beam lithography and reactive ion etching (RIE) Our samples show a 30 60% light output improvement when compared to unstructured reference crystals which is in close accordance with our simulation results. In addition, a theoretical investigation of the restrictions of the current PhC sample is given which concludes with prospects for improved future designs.", "author_names": [ "Arno Knapitsch", "Etiennette Auffray", "Christian Wolfgang Fabjan", "Jean Louis Leclercq", "Xavier Letartre", "Radoslaw Mazurczyk", "Paul Lecoq" ], "corpus_id": 7366122, "doc_id": "7366122", "n_citations": 26, "n_key_citations": 0, "score": 1, "title": "Effects of Photonic Crystals on the Light Output of Heavy Inorganic Scintillators", "venue": "IEEE Transactions on Nuclear Science", "year": 2013 }, { "abstract": "UV and /spl gamma/ ray excited luminescence and nuclear spectroscopy were used to study the relationship between the scintillation mechanisms of LSO and the spectroscopic characteristics obtained with PMT and APD readouts at room temperature. No correlation was found between scintillation decay time and light output. Like other investigators, we observed the existence of two distinct luminescence centers, Ce1 and Ce2, that mainly give rise to short (420 nm) and long (440 nm) emission wavelengths. Our measurements showed that different LSO crystals excited by /spl gamma/ rays have emission spectra with largely different shapes and maxima depending on the relative population and luminescence efficiency of these centers. It was also found that the poor energy resolution of LSO and YSO scintillators is well correlated with the coexistence of the two competing luminescence mechanisms. The prevalence of either Ce1 or Ce2 luminescence tends to reduce the variance of light emission and, thus, to improve energy resolution. Inversely, the coexistence of the two centers increases variance and degrades energy resolution.", "author_names": [ "A Saoudi", "Catherine M Pepin", "Daniel Houde", "Roger Lecomte" ], "corpus_id": 109737129, "doc_id": "109737129", "n_citations": 28, "n_key_citations": 4, "score": 0, "title": "Scintillation light emission studies of LSO scintillators", "venue": "1998 IEEE Nuclear Science Symposium Conference Record. 1998 IEEE Nuclear Science Symposium and Medical Imaging Conference (Cat. No.98CH36255)", "year": 1998 }, { "abstract": "In order to improve image quality in Positron Emission Tomography (PET) different routes are being pursued such as fast timing resolution for time of flight PET, higher spatial resolution by the use of smaller scintillator pixels and the use of depth of interaction information. The detection of the depth of interaction (DOI) of a gamma ray within a detector, deploying pulse shape discrimination (PSD) has been used to increase sensitivity and spatial resolution, especially at the edge of the field of view (FOV) The DOI information is used to reduce the parallax error; thus improving spatial resolution. Commonly, different scintillator materials with different decay times and light output and other differentiating factors, such as density, emission spectra, etc. are used for DOI detectors. We present a multilayer phoswich detector comprised of LSO with different decay times in the range from 30 ns to 47 ns. The difference in decay times is achieved by co doping LSO:Ce with Ca, resulting in short decay times of ~30 ns. The use of a cut light guide allows the use of regular Photomultiplier tubes, giving the opportunity of a potential DOI detector replacement for current detectors. We were able to identify each pixel in the different detector layers and thus, to determine the depth of the photon interaction and achieve a timing resolution of 345 ps.", "author_names": [ "Florian Bauer", "Mehmet Aykac", "Lars I Eriksson", "Matthias J Schmand" ], "corpus_id": 23583369, "doc_id": "23583369", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Depth of Interaction With a 3 Dimensional Checkerboard Arrangement LSO LSO Block", "venue": "IEEE Transactions on Nuclear Science", "year": 2010 }, { "abstract": "To improve the spatial resolution and uniformity in modern high resolution brain PET systems over the entire field of view (FOV) it is necessary to archive the depth of interaction (DOI) information and correct for spatial resolution degradation. In this work the authors present the performance results of a high resolution LSO/GSO phoswich block detector with DOI capability. This detector design will be used in the new CTI High Resolution Research Tomograph, ECAT HRRT. The two crystal layer (19/spl times/19/spl times/7.5 mm/sup 3/ and a light guide are stacked on each other and mounted on a (2/spl times/2) PMT set, so that the corners of the phoswich are positioned over the PMT centers. The crystal phoswich is cut into a 8/spl times/8 matrix of discrete crystals. The separation of the LSO and the GSO layer by pulse shape discrimination allows discrete DOI information to be obtained. The high light output and the light guide design results in an accurate identification of the 128 single crystals per block. Flood source measurements document a very good homogeneity of events, energy centroid stability and energy resolution (14 20% FWHM) per single crystal. An intrinsic resolution of /spl sim/1.3 mm and the DOI feasibility is extracted by coincidence measurements with a single GSO crystal.", "author_names": [ "Matthias J Schmand", "Lars A Eriksson", "Michael E Casey", "Mark S Andreaco", "Charles L Melcher", "Klaus Wienhard", "Gerd Flugge", "Ronald Nutt" ], "corpus_id": 78194215, "doc_id": "78194215", "n_citations": 73, "n_key_citations": 5, "score": 0, "title": "Performance results of a new DOI detector block for a high resolution PET LSO research tomograph HRRT", "venue": "1997 IEEE Nuclear Science Symposium Conference Record", "year": 1997 }, { "abstract": "To improve the spatial resolution and uniformity in modern high resolution brain PET systems over the entire field of view (FOV) it is necessary to archive the depth of interaction (DOI) information and correct for spatial resolution degradation. In this work the authors present the performance results of a high resolution LSO/GSO phoswich block detector with DOI capability. This detector design will be used in the new CTI High Resolution Research Tomograph, ECAT HRRT. The two crystal layer (19/spl times/19/spl times/7.5 mm/sup 3/ and a light guide are stacked on each other and mounted on a (2/spl times/2) PMT set, so that the corners of the phoswich are positioned over the PMT centers. The crystal phoswich is cut into a 8/spl times/8 matrix of discrete crystals. The separation of the LSO and the GSO layer by pulse shape discrimination allows discrete DOI information to be obtained. The high light output and the light guide design results in an accurate identification of the 128 single crystals per block. Flood source measurements document a very good homogeneity of events, energy centroid stability and energy resolution (14 20% FWHM) per single crystal. An intrinsic resolution of /spl sim/1.3 mm and the DOI feasibility is extracted by coincidence measurements with a single GSO crystal.", "author_names": [ "Matthias J Schmand", "Lars A Eriksson", "Michael E Casey", "Mark S Andreaco", "Charles L Melcher", "Klaus Wienhard", "Gerd Flugge", "Ronald Nutt" ], "corpus_id": 198472054, "doc_id": "198472054", "n_citations": 99, "n_key_citations": 3, "score": 0, "title": "Performance results of a new DOI detector block for a high resolution PET LSO research tomograph HRRT", "venue": "", "year": 1997 }, { "abstract": "Superlattice InAs/GaSb light emitting diodes with peak emission wavelength of 8.6 mm and output power approaching 190 mW at 77 K from a 120 x 120 mm2 mesa are demonstrated. Output power in excess of 600 m.W was demonstrated from a 520 x 520 mm mesa at 1 A drive current and 50% duty cycle. Devices were grown by molecular beam epitaxy on lightly n doped GaSb substrates and employed a 16 stage cascaded active region configuration to improve current efficiency and increase optical output. Emitting regions were coupled by semi metallic tunnel junctions consisting of a p GaSb layer and a thickness graded InAs/GaSb superlattice stack.", "author_names": [ "Edwin John Koerperick", "Dennis T Norton", "Jonathon T Olesberg", "B V Olson", "John P Prineas", "Thomas F Boggess" ], "corpus_id": 22816890, "doc_id": "22816890", "n_citations": 29, "n_key_citations": 2, "score": 0, "title": "Cascaded Superlattice InAs/GaSb Light Emitting Diodes for Operation in the Long Wave Infrared", "venue": "IEEE Journal of Quantum Electronics", "year": 2011 }, { "abstract": "Novel approach to improve the light extraction efficiency of InGaN quantum wells light emitting diodes (LEDs) using SiO2 microspheres was presented, leading to ~232% increase of the LEDs output power.", "author_names": [ "Yik-Khoon Ee", "Pisist Kumnorkaew", "Ronald A Arif", "James F Gilchrist", "Nelson Tansu" ], "corpus_id": 42536425, "doc_id": "42536425", "n_citations": 41, "n_key_citations": 7, "score": 0, "title": "Enhancement of Light Extraction Efficiency of InGaN Quantum Wells LEDs Using SiO2 Microspheres", "venue": "2007 Conference on Lasers and Electro Optics (CLEO)", "year": 2007 }, { "abstract": "As time of flight PET (TOF PET) gains popularity in clinical diagnostic, the coincidence timing resolution of PET systems becomes more crucial. The most common scintillators for commercial TOF PET systems are Lu based ones such as LSO or LYSO for their high light output, high density and fast decay time. Recently, LGSO with 0.025% Ce (LGSO fast) was developed which has faster decay time than LGSO with Ce concentration of 0.1 mol% (LGSO standard) Using the LGSO fast in conjunction with silicon photomultiplier (Si PM) may improve the timing performance for the development of TOF PET systems. Consequently, we tested the basic performance of LGSO fast and coupled them with Si PMs to measure the coincidence timing resolution using a high bandwidth digital oscilloscope. The performance was also evaluated for LGSO standard and other Lu based scintillators such as lutetium fine silicate (LFS) and two types of LYSOs from other manufacturers. The light output was largest for one of the LYSO from one manufacture and smallest for the LYSO from other manufacture. Decay time was fastest for LGSO fast (33.8 ns) and slowest for one of the LYSO (39.9 ns) Coincidence timing resolution for 2.9 mm long Lu based scintillators, LGSO fast was the best (156.5 ps) and one of the LYSO showed the worst (235.1 ps) For the 20 mm long scintillators, coincidence timing resolution was also best for LGSO fast (273.2 ps) and worst for one of the LYSO (481.8 ps) We conclude that LGSO fast combined with Si PM showed best timing performance among measured Lu based scintillators. Also within the same Lu based scintillators such as LYSOs, we found that the performance differences were sometimes significant and quality control of the Lu based scintillator is essential to achieve good performance in PET systems.", "author_names": [ "Seiichi Yamamoto", "Satoshi Okumura", "Natsuki Kato", "J Y Yeom" ], "corpus_id": 123799163, "doc_id": "123799163", "n_citations": 13, "n_key_citations": 1, "score": 0, "title": "Timing measurements of lutetium based scintillators combined with silicon photomultipliers for TOF PET system", "venue": "", "year": 2015 }, { "abstract": "1 Introduction 12 The CAPTAIN Detector 42.1 Cryostats 52.2 Cryogenics 62.3 Electronics 72.4 TPC 72.4.1 CAPTAIN TPC 72.4.2 Prototype TPC 92.5 Photon Detection System 92.6 Laser Calibration System 102.7 Special Run Modes 112.7.1 Tests of Doping Liquid Argon to Improve Light Output 113 Neutrons 123.1 Physics Importance 123.2 High intensity neutron running 143.3 Low intensity neutron running 153.3.1 Low energy neutron run 153.3.2 High energy neutron run 153.4 Run Plans 164 Neutrinos 174.1 Running at NuMI 174.1.1 On axis running in NuMI 174.1.2 O axis running in NuMI 204.2 Running at the SNS 204.3 Stopped Pion Source at the BNB 234.4 Other Neutrino Possibilities 245 Conclusions 251", "author_names": [ "The Captain Collaboration H Berns", "Hongsheng Chen", "David B Cline", "J R Danielson", "Z Djurcic", "Stephen R Elliott", "Gerald T Garvey", "Victor M Gehman", "Christopher Grant", "Elena Guardincerri", "Richard W Kadel", "Thomas Kutter", "D Lee", "Kwang-ryeol Lee", "Q P Liu", "W C Louis", "Christopher Michael Mauger", "C Mcgrew", "Robert McTaggart", "J Medina", "William J Metcalf", "Geoffrey B Mills", "Jacqueline Mirabal-Martinez", "Stuart Lee Mufson", "Emilija Pantic", "O Prokofiev Mufson", "Veljko Radeka", "J Ramsey", "Keith Rielage", "Himansu Sahoo", "Constantine Sinnis", "Michael Burghard Smy", "Walter Sondheim", "Ion Alexandru Stancu", "Robert C Svoboda", "Matthew Szydagis", "C Taylor", "A Teymourian", "Craig E Thorn", "Craig E Tull", "Martin Tzanov", "Rick van de Water", "H G Wang", "Chiaki Yanagisawa", "A Yarritu", "C Zhang" ], "corpus_id": 119268094, "doc_id": "119268094", "n_citations": 27, "n_key_citations": 2, "score": 0, "title": "The CAPTAIN Detector and Physics Program", "venue": "", "year": 2013 }, { "abstract": "Relevant information in positron emission tomography is currently being obtained mostly by analog signal processing methods. New digital PET scanner architectures are now becoming available, which offer greater flexibility and easier reconfiguration capability as compared to previous PET designs. Moreover, new strategies can be devised to extract more information with better accuracy from the digitized detector signals. Trained artificial neural networks (ANN) have been investigated to improve coincidence timing resolution with different types of Avalanche PhotoDiode (APD) based detectors. The signal at the output of a charge sensitive preamplifier was digitized with an off the shelf, free running 100 MHz, 8 bit analog to digital converter and time discrimination was performed with ANNs implemented in field programmable gate array (FPGA) Results show that ANNs can be particularly efficient with slow and low light output scintillators, such as BGO, but less so with faster luminous crystals, such as LSO. In reference to a fast PMT plastic detector, a time resolution of 6.5 ns was achieved with a BGO APD detector. With LSO, the ANN was found to be competitive with other digital techniques developed in previous works. ANNs implemented in FPGAs provide a fast and flexible circuit that can be easily reconfigured to accommodate various detectors under different signal/noise conditions.", "author_names": [ "Jean-Daniel Leroux", "D Rouleau", "Catherine M Pepin", "J -B Michaud", "Jules Cadorette", "Rejean Fontaine", "Roger Lecomte" ], "corpus_id": 25591540, "doc_id": "25591540", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Time Discrimination Techniques Using Artificial Neural Networks for Positron Emission Tomography", "venue": "IEEE Transactions on Nuclear Science", "year": 2009 } ]

[ { "abstract": "Our work aims to monitor wheat crop using a variety based approach by taking into consideration four different phenological stages of wheat crop development. In addition to highlighting the contribution of Red Edge vegetation indices in mapping wheat dry matter and nitrogen content dynamics, as well as using Random Forest regressor in the estimation of wheat yield, dry matter and nitrogen uptake relying on UAV (Unmanned Aerial Vehicle) multispectral imagery. The study was conducted on an experimental platform with 12 wheat varieties located in Sidi Slimane (Morocco) Several flight missions were conducted using eBee UAV with MultiSpec4C camera according to phenological growth stages of wheat. The proposed methodology is subdivided into two approaches, the first aims to find the most suitable vegetation index for wheat's biophysical parameters estimation and the second to establish a global model regardless of the varieties to estimate the biophysical parameters of wheat: Dry matter and nitrogen uptake. The two approaches were conducted according to six main steps: (1) UAV flight missions and in situ data acquisition during four phenological stages of wheat development, (2) Processing of UAV multispectral images which enabled us to elaborate the vegetation indices maps (RTVI, MTVI2, NDVI, NDRE, GNDVI, GNDRE, SR RE et SR NIR) (3) Automatic extraction of plots by Object based image analysis approach and creating a spatial database combining the spectral information and wheat's biophysical parameters, (4) Monitoring wheat growth by generating dry biomass and wheat's nitrogen uptake model using exponential, polynomial and linear regression for each variety this step resumes the varietal approach, (5) Engendering a global model employing both linear regression and Random Forest technique, (6) Wheat yield estimation. The proposed method has allowed to predict from 1 up to 21% difference between actual and estimated yield when using both RTVI index and Random Forest technique as well as mapping wheat's dry biomass and nitrogen uptake along with the nitrogen nutrition index (NNI) and therefore facilitate a careful monitoring of the health and the growth of wheat crop. Nevertheless, some wheat varieties have shown a significant difference in yield between 2.6 and 3.3 t/ha.", "author_names": [ "Ghizlane Astaoui", "Jamal Eddine Dadaiss", "Imane Sebari", "Samir Benmansour", "Ettarid Mohamed" ], "corpus_id": 234032612, "doc_id": "234032612", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Mapping Wheat Dry Matter and Nitrogen Content Dynamics and Estimation of Wheat Yield Using UAV Multispectral Imagery Machine Learning and a Variety Based Approach: Case Study of Morocco", "venue": "", "year": 2021 }, { "abstract": "As the semiconductor manufacturing design rules have been continually shrinking, the requirement in linewidth uniformity, linewidth roughness, line edge roughness, and overlay has been rising to stringent levels [1] In a FinFET process, the fins are made with 193 nm immersion lithography together with the Self Aligned Quadruple Patterning (SAQP) techniques. The linewidth uniformity, line edge roughness (LER) and linewidth roughness (LWR) are critical limiting factors in the process of SAQP as LER does not scale down with the dimensions of the devices. Three times the root mean square (3s) is the most common LER characterization parameter. In this paper, we have conducted a SAQP process study on a typical film stack based on a 5 nm logic process flow. We will make the SAQP patterns with domestically made etching machine and Atomic Layer Deposition (ALD) tools and will characterize all etch steps within the mandrel 1 and spacer 1 of SAQP process in terms of variations. We will benchmark the measured data against required targets in linewidth uniformity and line edge/width roughness. Moreover, we will present and analyze the result of our study.", "author_names": [ "Bowen Wang", "Yushu Yang", "Yibo Wang", "Yuning Zhu", "Yongjian Luo", "Qiang Wu", "Weihao Lin", "Zhunhua Liu", "Yanli Li", "Qingqing Wu", "Shoumian Chen", "Yuheng Zhang" ], "corpus_id": 229373257, "doc_id": "229373257", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Analysis of Linewidth Uniformity and Line Edge/Width Roughness in a 5 nm Logic SAQP Process", "venue": "2020 China Semiconductor Technology International Conference (CSTIC)", "year": 2020 }, { "abstract": "The utility model discloses a cleaning machine platform of a semiconductor packaging product, comprising a control panel, a cleaning operation area and a drying area, wherein the control panel is positioned at the upper part of the front surface of the machine platform and is used for realizing control of the cleaning process; the cleaning operation area is positioned in the middle of the front surface of the machine platform, is shaped like a hollow groove, and comprises more than one cleaning groove; the cleaning machine platform is provided with ultrasonic generating devices corresponding to all the cleaning grooves so as to clean the semiconductor packaging product in the cleaning groove by utilizing ultrasonic wave; the drying area is used for drying the cleaned product. The cleaning process comprises the steps of ultrasonic chemical cleaning, ultrasonic washing and drying. After cleaning, the adhesive residue on the semiconductor packaging product can be basically removed completely, so that the performance of the product is greatly improved, and simultaneously, the function test of a subsequent product is convenient.", "author_names": [ "" ], "corpus_id": 139605531, "doc_id": "139605531", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Cleaning machine platform of semiconductor packaging product", "venue": "", "year": 2010 }, { "abstract": "Based upon an existing or to be produced multi layered Semiconductor insulator Semiconductor carrier layer wafer (SOI Substrate) irregularity of the etching conditions between the center and the edge region occurring during dry etching can be counteracted by a number of alternative Steps, in particular, an additional layer construction compensating for the etching irregularity So that in any event an approxi mately homogeneous etching removal takes place over the entire area of the wafer to be etched.", "author_names": [ "Werner H Stemer", "Gregory L Mayback" ], "corpus_id": 143425926, "doc_id": "143425926", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "METHOD OF PRODUCING LARGE AREA MEMBRANE MASKS BY DRY ETCHING BACKGROUND OF THE INVENTION Field of the Invention", "venue": "", "year": 2017 }, { "abstract": "Wide gap II VI semiconductors have come of age with reports last year of blue lasing action in electrically driven devices. An ability to create nanostructures in II VI materials is improtant both to fabricate structures for physical examination and to make integrated optical devices likely to be required to match this new blue light source. In this paper we report the fabrication process required to fabricate nanostructures with dimensions down to 25nm in a variety of wide gap II VI materials using electron beam lithography and reactive ion etching in CH4/H2. The impact of fabrication steps upon the crystal quality, lattice vibrations and band edge emission has been studied studied by XPS, Raman scattering and low temperature luminescence. No signs of serious fabrication related damage is found using these techniques thus opening the doors for a whole range of novel semiconductor nanostructures", "author_names": [ "Clivia M Sotomayor Torres", "A P Smart", "Majeed A Foad", "Chris D W Wilkinson" ], "corpus_id": 136717237, "doc_id": "136717237", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Fabrication and spectroscopy of dry etched wide gap II VI semiconductor naonostructures", "venue": "", "year": 1992 }, { "abstract": "This paper presents a novel organic embedded trace damascene redistribution layer (RDL) process for panel scale 2.5 D interposers and high density fan out package (HDFO) substrates. A minimum feature size of 1.5 <inline formula> <tex math notation=\"LaTeX\"\\mu \\text{m} /tex math>/inline formula> line and space using ultrathin polymer dielectrics on glass, silicon, and as well as on organic laminate was demonstrated. This is the first demonstration of a complete set of materials and processes that can be applied to large glass or organic panels, to bridge the interconnect gap between current semiadditive process (SAP) RDL and wafer back end of line (BEOL) RDL. The ultra fine pitch multilayer RDL structures demonstrated in this paper achieve an optimum balance of high IO density, high electrical performance, and low process costs. IO density in terms of IOs per mm per layer, as defined by Intel, refers to the number of traces routed per millimeter of die edge on one RDL layer of an interposer or package substrate. The current SAP technology can achieve an IO density of about 40 IOs/mm/layer on 510 mm <inline formula> <tex math notation=\"LaTeX\"\\times 510$ /tex math>/inline formula> mm organic laminate panels. The challenges of fabricating copper metal traces below 5 <inline formula> <tex math notation=\"LaTeX\"\\mu \\text{m} /tex math>/inline formula> width and 5 <inline formula> <tex math notation=\"LaTeX\"\\mu \\text{m} /tex math>/inline formula> space using conventional SAP are discussed. On the other hand, wafer based BEOL damascene RDL technology can scale to IO densities of greater than 200 IOs/mm/layer, but at relatively higher costs on 300 mm diameter round wafers. An additional challenge for silicon interposers is low die to die interconnect data rate of single copper trace due to the high resistance of BEOL RDL structure. A combination of larger cross sectional area with high aspect ratio (AR) is preferred for low resistance, high bandwidth escape routing traces. In this paper, the materials and process flow of embedded trace damascene RDL technology featuring trenches of 1.5 <inline formula> <tex math notation=\"LaTeX\"\\mu \\text{m} /tex math>/inline formula> width and 1.5 <inline formula> <tex math notation=\"LaTeX\"\\mu \\text{m} /tex math>/inline formula> space with AR of 2 4 will be described. A new 5 <inline formula> <tex math notation=\"LaTeX\"\\mu \\text{m} /tex math>/inline formula> thick dry film photosensitive polymer dielectric IF4605 was used for the trench layer as well as the via layer. A large panel scalable Surface Planar DFS8910 tool was used to achieve a highly planar metal polymer RDL surface, at potentially lower costs than chemical mechanical polishing that has been used in prior work. The processes discussed in this paper will enable routing of fine copper traces on panel based interposers and HDFOs at higher throughput and potentially lower costs than BEOL processes. A two metal layer, 20 <inline formula> <tex math notation=\"LaTeX\"\\mu \\text{m} /tex math>/inline formula> IO pitch silicon like RDL test vehicle was fabricated with 2.5 <inline formula> <tex math notation=\"LaTeX\"\\mu \\text{m} /tex math>/inline formula> wide and 2.5 <inline formula> <tex math notation=\"LaTeX\"\\mu \\text{m} /tex math>/inline formula> space embedded traces and integrated with 2 <inline formula> <tex math notation=\"LaTeX\"\\mu \\text{m} /tex math>/inline formula> diameter microvias using IF4605 on glass. There was no pad in the integration. This pad less structure can be used for achieving theoretically maximum interconnect density. The process flow emulates the salient features of damascene processes used for BEOL RDL on semiconductor wafers, but simplifies them using dry film polymer materials and panel processes. Hence, it is referred to as organic embedded trace damascene or simplified as an organic damascene process (ODP) in this paper. The novel ODP interconnect addresses the current limitations of both SAP and BEOL processes. The key highlights of this new ODP technology are: 1) IO densities of 200 IO/mm/layer or more; 2) via to via pitch of <inline formula> <tex math notation=\"LaTeX\"$20~\\mu \\text{m} /tex math>/inline formula> or less; 3) high AR of routing traces in the range of 2 4; 4) precise RDL linewidth control; 5) double sided process with glass core; and 6) reduced number of process steps and panel scalability leading to lower fabrication costs.", "author_names": [ "Fuhan Liu", "Chandrasekharan Nair", "A Kubo", "Tomoyuki Ando", "Frank L Wei", "Venky Sundaram", "Rao R Tummala" ], "corpus_id": 13711449, "doc_id": "13711449", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Organic Damascene Process for 1.5 \\mu$ m Panel Scale Redistribution Layer Technology Using 5 \\mu$ m Thick Dry Film Photosensitive Dielectrics", "venue": "IEEE Transactions on Components, Packaging and Manufacturing Technology", "year": 2018 }, { "abstract": "This original study investigates the damages of WC 6Co uncoated carbide tools during dry turning of AISI 1045 steel at mean and high speeds. The different wear micromechanisms are explained on the basis of different microstructural observations and analyses made by different techniques: (i) optical microscopy (OM) at macro scale, (ii) scanning electron microscopy (SEM) with back scattered electron imaging (BSE) at micro scale, (iii) energy dispersive spectroscopy (EDS) X ray mapping with wavelength dispersive spectroscopy (WDS) for the chemical analyses and (iv) temperature evolution during machining. We noted that at conventional cutting speed Vc 250 m/min, normal cutting tool wear types (adhesion, abrasion and built up edge) are clearly observed. However, for cutting speed Vc 250 m/min a severe wear is observed because the behavior of the WC 6Co grade completely changes due to a severe thermomechanical loading. Through all SEM micrographs, it is observed that this severe wear consists of several steps as: excessive deformation of WC 6Co bulk material and binder phase (Co) deformation and intragranular microcracking of WC, WC grain fragmentation and production of WC fragments in the tool/chip contact. Thus, the WC fragments accumulated at the tool/chip interface cause abrasion phenomena and pullout WC from tool surface. WC fragments contribute also to the microcutting and microploughing of chips, which lead to form a transferred layer at the tool rake face. Finally, based on the observations of the different wear micromechanisms, a scenario of WC 6Co damages is proposed through to a phenomenological model", "author_names": [ "Tchadja Kagnaya", "Christine Boher", "Laurence Lambert", "Myriam Lazard", "Thierry Cutard" ], "corpus_id": 137346243, "doc_id": "137346243", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "Microstructural analysis of wear micromechanisms of WC 6Co cutting tools during high speed dry machining", "venue": "", "year": 2014 }, { "abstract": "Single crystal silicon carbide (SiC) is a new semiconductor material that has a great potential to be widely used. However, SiC is a kind of difficult to machine material due to its extreme hardness and brittleness. The present study investigated the machinability of single crystal SiC using dry laser and three different water laser co machining processes. The results indicate that using the hybrid laser waterjet micro machining to micro groove single crystal SiC can derive the clean and straight edges and thermal damage free grooves.", "author_names": [ "Shaochuan Feng", "Chuanzhen Huang", "Jun Wang", "Hong Zhu", "Peng Yao", "Liang De Wang" ], "corpus_id": 138386140, "doc_id": "138386140", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "A Comparison among Dry Laser Ablation and Some Different Water Laser Co Machining Processes of Single Crystal Silicon Carbide", "venue": "", "year": 2016 }, { "abstract": "The invention provides a method for manufacturing a gap wall of a semiconductor device. The method at least comprises the steps of forming a gate structure on a substrate; successively forming a first oxide layer and a second oxide layer on the surface of the gate structure; performing dry method on the second oxide layer until the second oxide layer becomes a film; and performing wet method etching on the residual second oxide layer and the first oxide layer, thereby reserving the second oxide layer and the first oxide layer on two sidewalls of the gate structure, and exposing the first oxide layer. The method for manufacturing the gap wall of the semiconductor device has functions of realizing relatively uniform thickness of the first oxide layer which residues on the top surface and the edge of the gate structure, effectively ensuring electrical performance and operation speed of the semiconductor device, and improving yield of the semiconductor device.", "author_names": [ "" ], "corpus_id": 146711965, "doc_id": "146711965", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Method for manufacturing gap wall of semiconductor device", "venue": "", "year": 2014 }, { "abstract": "Next generation semiconductor devices and evolving opportunities in nanoelectronics present new challenges for fabrication technology. These include patterning and structure generation to define the smallest features, the deposition of metals, metal oxides, and other functional layers within challenging topographies, and development of the associated integration steps necessary to create working devices. Implementation of emergent technical solutions, however, is also subject to economic realities that require high volume process tools, reliability, and low cost per device layer. Changes in semiconductor process technology have to date largely been driven by the continued downscaling of device features to increase transistor density. Leading edge microprocessors are currently in production at the 45 nm device node. Device dimensions approaching 22 nm will be realized withinin the next several years. As manufacturing moves to smaller and smaller features, it is necessary to re evaluate process technology and decide if evolutions in current methods are sufficient or if technical and/or economic considerations will mandate change. Semiconductor fabrication relies on a combination of gas (or vapor) based techniques and liquid phase processing. Each has its advantages. Gas phase techniques allow for dry processing, complete wetting of surfaces, and the absence of surface tension, which in turn allows facile transport of reagents into confined geometries. Vapor phase transport of reagents and processing aids, however, are subject to species volatility constraints. Liquid phase processes have the advantage of species transport in solution, but the presence of the liquid phase can give rise to contamination issues, sluggish mass transport, and difficulties such as pattern collapse for the smallest device features. The latter arises from surface tension and associated capillary forces. These limitations are especially relevant for processing and fabrication at the nanoscale.", "author_names": [ "Alvin Horatio Romang", "James J Watkins" ], "corpus_id": 7887018, "doc_id": "7887018", "n_citations": 81, "n_key_citations": 0, "score": 0, "title": "Supercritical fluids for the fabrication of semiconductor devices: emerging or missed opportunities?", "venue": "Chemical reviews", "year": 2010 } ]

[ { "abstract": "As electronic devices are evolving to more diversified and specifically function oriented applications, silicon based semiconductors have shown their limitation to unprecedented functionality requirements such as high power, high frequency, and high temperature operation. Growing utilization of IV IV compounds (e.g. SiGe, SiC) III V compounds (e.g. GaAs, GaN) as well as hetero epitaxial structures with Si has become an inevitable trend. Due to cost and size of SiC and GaN wafers, epitaxial deposition on Si is utilized. However, this requires an efficient pre epitaxial wet cleaning of the Si wafer yielding the lowest defects possible. In this study, different HF last processes were tested yielding that an in situ process with dilute chemicals gives the best results.", "author_names": [ "Darian Waugh", "Gim S Chen", "Jennifer Boecker", "Ismail I Kashkoush" ], "corpus_id": 212636454, "doc_id": "212636454", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Application of In situ Pre epi Clean Process for Next Generation Semiconductor Devices", "venue": "2019 16th China International Forum on Solid State Lighting 2019 International Forum on Wide Bandgap Semiconductors China (SSLChina: IFWS)", "year": 2019 }, { "abstract": "Epitaxial deposition of strained Si and SiGe to improve electron and hole mobility and Vt shift is becoming more and more part of the standard CMOS processing [1,2] One of the most important restrictions imposed on advanced CMOS processing is that on thermal budget. For epitaxial growth processes this thermal budget is quite high. The main contribution comes however not from the growth itself, but from the in situ H2 bake necessary to remove any oxide traces left prior to epi. Without any pre epi etch, removal of the native oxide requires at least a bake for several minutes at 900 C or higher. When combined with a wet clean which removes the native oxide and passivates the surface (usually H or Cl) this temperature can be reduced to the range of 850 750 C, although this is always at the cost of a remaining C and O peak at the epi substrate interface.", "author_names": [ "Ken-ichi Sano", "Frederik E Leys", "G Dilliway", "Roger Loo", "Paul W Mertens", "Jim Snow", "Akira Izumi", "Atsuro Eitoku" ], "corpus_id": 137455405, "doc_id": "137455405", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Challenges of Single Wafer Wet Cleaning for Low Temperature Pre Epitaxial Treatment of SiGe", "venue": "", "year": 2007 }, { "abstract": "Locally strained Si technology using embedded SiGe has been used to improve pMOSFET device performance through hole mobility enhancement. Embedded SiGe is achieved by selectively growing epitaxial SiGe film in recessed Si pMOSFET source and drain areas. Prior to selective SiGe epi growth, a thin layer of Si seed was employed to help nucleate following low temperature selective SiGe epitaxial film in recessed source and drain areas. In combination with pre epi wet clean and low temperature chemical bake, use of Si seed resulted in improved SiGe film morphology and micro loading effect, and further improved device performance.", "author_names": [ "Po-Lun Cheng", "Chin I Liao", "Chin Cheng Chien", "C L Yang", "S F Ting", "Li-Shian Jeng", "Cheng Tung Huang", "Osbert Cheng", "S F Tzou", "Wensyang Hsu" ], "corpus_id": 73532764, "doc_id": "73532764", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Effectiveness of Si thin buffer layer for selective SiGe epitaxial growth in recessed source and drain for pMOS", "venue": "", "year": 2008 }, { "abstract": "A thin layer (15A) of Si seed was employed to help nucleate low temperature selective SiGe epitaxial film in recessed source and drain. In combination with pre epi wet clean and low temperature chemical bake, use of Si seed resulted in improved SiGe film morphology and micro loading effect, and further improved dislocation on the lateral recess interface. Introduction Locally strained Si technology using embedded SiGe has demonstrated improved pMOSFET device performance through hole mobility enhancement [1 3] Widely used, embedded SiGe is achieved by selectively growing epitaxial SiGe film in recessed Si source and drain in the pMOSFET area. Typical process steps for recessed source and drain SiGe flow is described elsewhere [2] Prior to selective SiGe epi growth, multiple implants and dry etch of source and drain result in surface damage and chemical residues. Surface quality and cleanliness of the etched Si surfaces have great impact on the morphology and SiGe film quality. Typically, wet clean (in diluted HF) or high temperature bake 800 degC) is used as a preepi step to remove surface C and O. Previous study [4] indicated improvement of SiGe film morphology by multiple cycles of wet clean in ozonated DI/SC1/DHF. For most harsh surfaces with severe damage casued by implant and dry etch, use of Si seed layer is employed to nucleate uniform SiGe film with good quality and to minimize micro loading effect. Experiments and Results Prior to SiGe deposition, device wafers were cleaned in ozonated DI, SC1, and dipped in diluted HF (DHF) Wafers were introduced to the reaction chamber for low temperature bake followed by selective deposition of Si seed and SiGe film in recessed source and drain areas in the pMOS area. Control wafer was process with similar pre epi wet clean, bake, and deposition without the seed layer. Wafers with severe surface damage did not yield SiGe film growth of good morphology without the seed layer. However, wafers with surface damage resulted in difference in SiGe film morphology with or without the Si seed as shown in Figure 1 and Figure 2. Improved surface morphology is observed as clear faceting and dislocation free around the lateral recess interface in the case with the Si seed. Also, the surface roughness can be healed well in the different density area of wafer by Si seed, further improve micro loading with the similar incubation time. Micro loading between isolated area and dense area was improved 92% once Si seed layer was applied. Besides, Si seed implement not only decrease micro loading effect but also without SiGe quality degradation. Micro loading was defined as (maximum thickness minimum thickness)/minimum thickness in the same die. (a) (b) Figure 1. Comparison of morphology of selective grown SiGe film (a) with and (b) without Si seed.", "author_names": [ "Po-Lun Cheng", "Chin I Liao", "Houxiao Wu", "Yi Cheng Chen", "Chin Cheng Chien", "Chan Lon Yang", "S F Tzou", "Jinsong Tang", "Yonah Cho", "Errol Antonio C Sanchez", "Vincent C Chang", "T Fu", "Wensyang Hsu" ], "corpus_id": 112939845, "doc_id": "112939845", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Effectiveness of Si Seed for Selective SiGe Epitaxial Deposition in Recessed Source and Drain for Locally Strained pMOS Application", "venue": "", "year": 2006 }, { "abstract": "Abstract Motivated by the need to grow fast high quality virtual substrates (VS) for strained Si SiGe channels or for Ge/GaAs applications, Unaxis Semiconductors has developed low energy plasma processes (LEPP) which are running on a new LEPP 300 cluster tool. The system combines the utilisation of plasma for pre epi clean and for epitaxial growth in a production system. It consists of two new processes both applicable for 300 mm wafers: the LEPC (low energy plasma cleaning) process, a dry low temperature (unkeyable??150 degC) process for wafer cleaning before epitaxial growth (pre epi clean) and the LEPECVD (low energy plasma enhanced CVD) a deposition process which allows deposition rates in the range between 0.01 nm/s and several nm /s at 550degC.", "author_names": [ "Jurgen Ramm" ], "corpus_id": 110276660, "doc_id": "110276660", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Low energy plasma processing (LEPP) for SiGe applications", "venue": "", "year": 2002 }, { "abstract": "", "author_names": [ "Kurt Wostyn", "Dirk Rondas", "Roger Loo", "Sathish Kumar Dhayalan", "Andriy Hikavyy", "Wim Elskens", "Alex Vyncke", "Paul W Mertens", "Frank Holsteyns", "Stefan De Gendt", "Toru Masaoka", "Yukifumi Yoshida", "Gerhard Bast", "Gavin Simpson" ], "corpus_id": 138405832, "doc_id": "138405832", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Enabling GeH4 HCl in situ pre epi clean: impact of water quality on HF last process performance", "venue": "", "year": 2015 }, { "abstract": "", "author_names": [ "V Machkaoutsan", "Keith Doran Weeks", "Matthias Bauer", "J W Maes", "John Tolle", "Shawn G Thomas", "A Alian", "Andriy Hikavyy", "Roger Loo" ], "corpus_id": 138534287, "doc_id": "138534287", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "High Efficiency Low Temperature Pre epi Clean Method for Advanced Group IV epi Processing", "venue": "", "year": 2013 }, { "abstract": "Further improving complementary metal oxide semiconductor (CMOS) performance beyond the 15 nm generation likely requires the use of high mobility materials like Ge for pMOS devices. However, Ge pMOS devices made in relaxed Ge do not outperform current state of the art uni axially strained Si pMOS devices. This explains the current interest in compressively strained Ge like bi axially strained Ge grown on top of SiGe Strain Relaxed Buffers. From a device integration point of view, the surface smoothness of the strained Ge layer is an important parameter which has so far not widely been reported in literature, in contrast to other parameters like the material quality (crystallinity) and the threading dislocation density. In this paper we report the post CMP and pre epi cleans which are required to obtain contamination free SiGe surfaces to enable defect free strained Ge growth without reoccurrence of the surface roughening. We will demonstrate the epitaxial growth of fully strained 20 nm thick Ge epitaxially grown on top of SiGe Strain Relaxed Buffers with 85% Ge with a surface roughness as low as 1.6 A (as measured on areas of 10x10 um2)", "author_names": [ "Roger Loo", "Laurent Souriau", "Patrick Ong", "Karine Kenis", "Jens Rip" ], "corpus_id": 137379184, "doc_id": "137379184", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Optimized Post CMP and Pre Epi Cleans to Enable Smooth and High Quality Epitaxial Strained Ge Growth on SiGe Strain Relaxed Buffers", "venue": "", "year": 2012 }, { "abstract": "", "author_names": [ "Mireia Bargallo Gonzalez", "Nicole K Thomas", "Eddy Simoen", "Peter Verheyen", "Andriy Hikavyy", "Frederik E Leys", "Yasutoshi Okuno", "Bertrand Vissouvanadin Soubaretty", "Benny van Daele", "Luc Geenen", "Roger Loo", "Cor Claeys", "V Machkaoutsan", "Pierre Tomasini", "Shawn G Thomas", "Jiong Ping Lu", "J W Weijtmans", "R Wise" ], "corpus_id": 135528195, "doc_id": "135528195", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Analysis of the Pre epi Bake Conditions on the Defect Creation in Recessed SiGe S/D Junctions", "venue": "", "year": 2007 }, { "abstract": "Several device concepts have been further evaluated after the successful implementation of epitaxial Si, SiGe and/or Si:C layers. Most of the next device generations will put limitations on the thermal budget of the deposition processes without making concessions on the epitaxial layer quality. In this work we address the impact of ex situ wet chemical cleans and in situ pre epi bake steps, which are required to obtain oxide free Si surfaces for epitaxial growth. The combination of defect measurements, Secondary Ion Mass Spectroscopy, photoluminescence, lifetime measurements, and electrical diode characterization gives a very complete overview of the performance of low temperature pre epi cleaning methods. Contamination at the epi/substrate interface cannot be avoided if the pre epi bake temperature is too low. This interface contamination is traceable by the photoluminescence and lifetime measurements. It may affect device characteristics by enhanced leakage currents and eventually by yield issues due to SiGe layer relaxation or other defect generation. A comparison of state of the art 200 mm and 300 mm process equipment indicates that for the same thermal budgets the lowest contamination levels are obtained for the 300 mm equipments.", "author_names": [ "Roger Loo", "Andriy Hikavyy", "Frederik E Leys", "Masayuki Wada", "Ken-ichi Sano", "Brecht De Vos", "Antoine Pacco", "Mireia Bargallo Gonzalez", "Eddy Simoen", "Peter Verheyen", "W Vanherle", "Matty Caymax" ], "corpus_id": 137538711, "doc_id": "137538711", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "Low Temperature Pre Epi Treatment: Critical Parameters to Control Interface Contamination", "venue": "", "year": 2008 } ]

[ { "abstract": "It is estimated that 884 million people lack access to improved water supplies. Many more are forced to rely on supplies that are microbiologically unsafe, resulting in a higher risk of waterborne diseases, including typhoid, hepatitis, polio, and cholera. Due to poor sanitation and lack of clean drinking water, there are around 4 billion cases of diarrhea each year resulting in 2.2 million deaths, most of these are children under five. While conventional interventions to improve water supplies are effective, there is increasing interest in household based interventions to produce safe drinking water at an affordable cost for developing regions. Solar disinfection (SODIS) is a simple and low cost technique used to disinfect drinking water, where water is placed in transparent containers and exposed to sunlight for 6 hours. There are a number of parameters which affect the efficacy of SODIS, including the solar irradiance, the quality of the water, and the nature of the contamination. One approach to SODIS enhancement is the use of semiconductor photocatalysis to produce highly reactive species that can destroy organic pollutants and inactivate water pathogens. This paper presents a critical review concerning semiconductor photocatalysis as a potential enhancement technology for solar disinfection of water.", "author_names": [ "John Anthony Byrne", "Pilar Fernandez-Ibanez", "Patrick Stuart Morris Dunlop", "Dheaya Alrousan", "Jeremy William John Hamilton" ], "corpus_id": 54494030, "doc_id": "54494030", "n_citations": 191, "n_key_citations": 5, "score": 1, "title": "Photocatalytic Enhancement for Solar Disinfection of Water: A Review", "venue": "", "year": 2011 }, { "abstract": "", "author_names": [ "Anvith Deeconda" ], "corpus_id": 139540637, "doc_id": "139540637", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The Effect Of Different Photocatalytic Semiconductors On The Enhancement Of PET Solar Disinfection Of E. coli contaminated Water Sources", "venue": "", "year": 2015 }, { "abstract": ".v Chapter 1: Introduction. 1 Chapter 2: Synthesis and Characterization of MoS2 TiO2 Complex..6 Synthesis..6 Characterization..8 XRD results..8 UV Vis results..15 Fourier transform infrared spectroscopy (FTIR) results..18 SEM results..22 Chapter 3: Testing the Effectiveness of MoS2 TiO2 in Water Disinfection..30 Background..30 Experimental setup..30 Preparation of nanomaterial inserts..32 Preparation of E. coli broth suspension..33 Preparation of agar plates with medium..33 Culturing of E. coli..34 Colony count through serial dilution..37 Experimental procedure: testing disinfection properties of the nanomaterials..38 Results and Discussion..40 Experiment 1: Pure TiO2 disinfection properties..40 Experiment 2: 1.5% MoS2 98.5% TiO2 disinfection properties..41 Experiment 3: 5% MoS2 95% TiO2 disinfection properties..42 Experiment 4: 10% MoS2 90% TiO2 disinfection properties..44 Experiment 5: No insert disinfection properties..45 Discussion..47 Chapter 4: Conclusions. 50 Chapter 5: References Cited. 51 Appendix A..55", "author_names": [ "Timothy McColgan" ], "corpus_id": 139441805, "doc_id": "139441805", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "MoS2 Doped TiO2 Nanomaterial and the Enhancement of Photocatalytic Properties for Solar Disinfection", "venue": "", "year": 2018 }, { "abstract": "Abstract Interest has grown in the modification of titanium dioxide with graphene to improve the photocatalytic behaviour. In this work, titanium dioxide reduced graphene oxide (TiO2 RGO) composites were synthesised by the photocatalytic reduction of exfoliated graphene oxide (GO) by TiO2 (Evonik P25) under UV irradiation in the presence of methanol as a hole acceptor. The composite materials were characterised using high resolution transmission electron microscopy (HRTEM) X ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Raman and XPS analysis provided evidence that GO was converted to RGO by photocatalytic reduction. The TiO2 RGO composites were compared to TiO2 in suspension reactors for the disinfection of water contaminated with Escherichia coli and Fusarium solani spores under real sunlight. Very rapid water disinfection was observed with both E. coli and F. solani spores. An enhancement in the rate of inactivation of E. coli was observed with the TiO2 RGO composite compared to P25 alone. The rate of inactivation of F. solani spores was similar for both the TiO2 RGO and P25. When the major part of the solar UVA was cut off (l 380 nm) using a methacrylate screen, there was a marked increase in the time required for inactivation of E. coli with P25 but no change in the inactivation rate for the TiO2 RGO. There is evidence of singlet oxygen production with visible light excitation of the TiO2 RGO composites which would lead to E. coli inactivation.", "author_names": [ "Pilar Fernandez-Ibanez", "Maria Inmaculada Polo-Lopez", "Sixto Malato", "Shikha Wadhwa", "Jeremy William John Hamilton", "P S M Dunlop", "Raechelle A D'Sa", "Erin Magee", "Kevin E O'Shea", "Dionysios D Dionysiou", "John Anthony Byrne" ], "corpus_id": 93592459, "doc_id": "93592459", "n_citations": 114, "n_key_citations": 0, "score": 0, "title": "Solar photocatalytic disinfection of water using titanium dioxide graphene composites", "venue": "", "year": 2015 }, { "abstract": "The solar water disinfection method (SODIS) was modified by the addition of a photocatalytic layer of titania on the interior surface of polyethylene terephthalate (PET) and acrylic bottles. Titania was solvent deposited on the interior of commercially available PET bottles, as well as bottles that were constructed from acrylic. Uncoated and titania coated acrylic bottles removed 3,000,000 5,000,000 colony forming units per milliliter of K12 E. coli from 670 mL of contaminated water in 40 min of solar irradiance. After five hours of sunlight exposure, the concentration of 10 ppm methyl orange (a representative organic water contaminant) was reduced by 61% using the titania coated acrylic bottles. The concentration of 87 ppb microcystin LR (a representative algal toxin) was reduced by 70% after 7 hours of sunlight exposure in the titania coated acrylic bottles. Acrylic is an effective alternative to PET for use in the SODIS method due to its greater UV transparency. The addition of titania to PET and acrylic bottles confers the ability to remove chemical contaminants in addition to inactivating microbiological contaminants.", "author_names": [ "Jonathan M Carey", "T M Perez", "E G Arsiaga", "Lucas Loetscher", "Joel E Boyd" ], "corpus_id": 36327728, "doc_id": "36327728", "n_citations": 10, "n_key_citations": 2, "score": 0, "title": "The photocatalytic enhancement of acrylic and PET solar water disinfection (SODIS) bottles.", "venue": "Water science and technology a journal of the International Association on Water Pollution Research", "year": 2011 }, { "abstract": "Abstract This study presents a simple method of titanium dioxide modification by carbon. Monosaccharide (fructose) was used as the carbon source. The pressure modification using fructose caused enhancement of antibacterial efficiency. It was found that prepared photocatalysts were capable of total Escherichia coli and Staphylococcus epidermidis inactivation under the UV A and artificial solar light, which was attributed to the changes of the surface characteristics, i.e. zeta potential. The best results were observed for the TiO2 F 1% 100 photocatalyst, containing 0.51 wt% of carbon with less negative zeta potential 18.08 mV) The two stage photocatalytic mechanism of bacteria destruction by OH radicals was found. Obtained data suggest that fructose modified photocatalysts may be useful in the development of alternative water disinfectants.", "author_names": [ "Paulina Rokicka-Konieczna", "Agata Markowska-Szczupak", "Ewelina Kusiak-Nejman", "Antoni W Morawski" ], "corpus_id": 145885057, "doc_id": "145885057", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Photocatalytic water disinfection under the artificial solar light by fructose modified TiO2", "venue": "Chemical Engineering Journal", "year": 2019 }, { "abstract": "Abstract It is estimated that 780 million people lack access to improved water supplies and many more are forced to rely on sources that are microbiologically unsafe. While piped in water supplies are the ultimate goal for the provision of water in developing countries, low cost point of use disinfection treatments could help to significantly reduce the incidence of water borne disease. Solar disinfection of water (SODIS) is a simple method of treating water where the UV and thermal energy of the sun act to inactivate pathogenic microorganisms in water; however, the recommended protocol is 6 h under direct sunlight, the efficiency depends on environmental factors, and some pathogens are more resistant to solar disinfection. The use of compound parabolic collectors (CPC) and immobilised titanium dioxide for photocatalysis were investigated as enhancement technologies for solar disinfection. The reactors consisted of borosilicate glass tubes (1.5 m in length) as either single tubes of diameter 50 mm or two concentric tubes (inner tube of diameter 32 mm) with and without CPC. For solar photocatalytic disinfection (SPC DIS) the inside wall of the 50 mm tube was dip coated with TiO 2 (TiO 2 Evonik P25 and/or the outside wall of the 32 mm tube. SPC DIS and SODIS were tested under flow conditions using different reactor configurations under real sun conditions. E. coli was used as the model microorganism for the disinfection studies in 0.9% saline solution and the total volume in each experiment was 7 L. It was found that the use of CPCs improved the SODIS and SPC DIS efficiency. The disinfection kinetics were observed to follow a log linear with shoulder and/or tailing model. The kinetic parameters were determined using the UVA dose as the independent variable and the configurations were compared for E. coli inactivation efficiency based on the log of the residual concentration (Log N res and the first order rate constant k Three reactor configurations showed a residual bacterial count below the detection limit and they were compared based upon the first order rate constant. The concentric tube arrangement (a tube within a tube) with CPC was the most effective configuration. The following order was found for k where coated refers to TiO 2 coating and the equals sign indicates no significant difference; uncoated external coated internal double coated tube uncoated double tube. It is known that E. coli is inactivated by SODIS and it may be a 'soft' target for comparing the effectiveness of SODIS vs SPC DIS. Nevertheless, photocatalysis presents advantages in terms of the non recovery of inactivated organisms and the inactivation of SODIS resistance organisms.", "author_names": [ "Dheaya Alrousan", "Maria Inmaculada Polo-Lopez", "P S M Dunlop", "Pilar Fernandez-Ibanez", "John Anthony Byrne" ], "corpus_id": 94402191, "doc_id": "94402191", "n_citations": 72, "n_key_citations": 3, "score": 0, "title": "Solar photocatalytic disinfection of water with immobilised titanium dioxide in re circulating flow CPC reactors", "venue": "", "year": 2012 }, { "abstract": "Solar water disinfection (SODIS) is an effective, simple, household level, point of use technology suitable for application in developing countries. Contaminated water is placed in a plastic container (typically a 2L PET bottle) and exposed to sunlight for at least 6 hours. Laboratory and field trials have demonstrated SODIS to effective against a wide range of waterborne pathogens with health impact assessments demonstrating significant benefits from consumption of SODIS treated water. Photocatalytic (PC) enhancement of the SODIS process could provide larger volumes of safe drinking water and reduce the sunlight exposure time. Pilot scale, modular PC SODIS reactors were designed and constructed from low cost materials and tested, under real sunlight the south of Spain, for their efficiency to disinfect water containing ~1 x10 6 Escherichia coil cells/mL. The inclusion of an immobilised nanostructured titanium dioxide coating within 1.25 L static batch and 7 L re circulating reactors accelerated the rate of disinfection with 6 log kill observed in 3 hours. Complete disinfection was not observed in re circulating SODIS reactors. Photocatalytic enhancement was observed during full sun and cloudy weather conditions.", "author_names": [ "P S M Dunlop", "Dheaya Alrousan", "Maria Inmaculada Polo-Lopez", "Pilar Fernandez-Ibanez", "John Anthony Byrne" ], "corpus_id": 55453139, "doc_id": "55453139", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Photocatalytic enhancement of solar water disinfection for application in developing regions", "venue": "", "year": 2009 }, { "abstract": "Abstract The enhancement of current technologies used to treat polluted water is one of the most important challenges in water research. The application of physico chemical treatments could reduce the load of chemical and biological pollutants present in WW reducing the pressure over water requirements, allowing the reclaim of the treated water. Advanced Oxidation Processes (AOPs) and, in particular, photocatalysis using titanium dioxide (TiO 2 have shown a great potential for chemicals removal as well as for pathogens reduction in water. Moreover, the use of solar Compound Parabolic Collectors (CPC) reactors has been also shown to be very effective for water treatment purpose by solar photocatalysis. Nevertheless, the effects of some key parameters in photocatalytic disinfection have not been already investigated at pilot scale in solar reactors; like dissolved oxygen concentration, water temperature, water matrix composition and the type of microorganism. The roles of these parameters in photocatalytic processes are individually known for chemicals degradation, but their relative significance in water photocatalytic disinfection has been never studied at pilot scale. The aim of this work was to investigate the influence of these parameters on the disinfection efficiency using a solar 60 L CPC reactor with suspended TiO 2 (100 mg/L) The following variables were experimentally evaluated: injection of air in the reactor (160 L/h) different controlled temperatures (15, 25, 35 and 45 degC) two very different models of water pathogen, Escherichia coli (model of fecal water contamination) and Fusarium solani spores (a highly phytopathogenic fungus) and the chemical composition of the water comparing urban WW effluents (UWWE) and simulated urban WW effluent (SUWWE) The increase of water temperature (from 15 to 45 degC) had a benefit on the disinfection rate for both pathogens in all the experimental conditions evaluated. The air injection led to an important enhancement on the inactivation efficiency, which was stronger for F. solani spores, the most resistant microorganisms to TiO 2 photocatalysis. The composition of the water matrix significantly affected the efficiency of the photocatalytic treatment, showing a better inactivation rate in SUWWE than for UWWE.", "author_names": [ "Irene Garcia-Fernandez", "I Fernandez-Calderero", "Maria Inmaculada Polo-Lopez", "Pilar Fernandez-Ibanez" ], "corpus_id": 95536620, "doc_id": "95536620", "n_citations": 60, "n_key_citations": 0, "score": 0, "title": "Disinfection of urban effluents using solar TiO2 photocatalysis: A study of significance of dissolved oxygen, temperature, type of microorganism and water matrix", "venue": "", "year": 2015 }, { "abstract": "The objective of this work was to assess the effectiveness of using near UV light to disinfect water supplies for potential applications in developing countries. A pilot scale photoreactor comprised of non tracking compound parabolic collectors installed at Plataforma Solar de Almeria was examined and a comparison of disinfection efficiency using E. coli K 12 was carried out with a reactor configuration of 3 and 1 m2 illuminated area. Tests were also carried out using suspensions of titanium dioxide (TiO2) at concentrations ranging from 0 to 9 mg/l. The removal of E. coli K 12 from initial concentrations of 1 x 105 CFU/ml to below the limit of detection was achieved both with and without the use of TiO2. Levels of inactivation in 35 l of inoculated water of up to 4 log removal were achieved in under 30 min. The addition of TiO2 created an enhancement to the process only at the 3 mg/l dose. However, the results have also suggested the possibility that another disinfection mechanism, possibly governed by the frequency of intermittent UV light exposure, was regulating the overall inactivation kinetics of the trials.", "author_names": [ "O A McLoughlin", "Pilar Fernandez Ibanez", "Wolfgang Gernjak", "Sixto Malato Rodriguez", "Laurence W Gill" ], "corpus_id": 119755309, "doc_id": "119755309", "n_citations": 65, "n_key_citations": 3, "score": 0, "title": "Photocatalytic disinfection of water using low cost compound parabolic collectors", "venue": "", "year": 2004 } ]

[ { "abstract": "The invention provides a manufacturing method of an MOSFET (Metal Oxide Semiconductor Field Effect Transistor) device, which is characterized by comprising the steps of forming a mask layer on a substrate; carrying out etching on the substrate by taking the mask layer as a mark, and simultaneously forming a first groove and a second groove; forming a first filling layer in the first groove, and forming a shielding layer on the first filling layer; carrying out etching on the second groove by taking the shielding layer and the mask layer as a mask so as to enable the depth of the second groove to increase to preset depth and form a third groove; and forming a second filling layer in the third groove. According to the manufacturing method of the MOSFET device, the first groove and the second groove are formed simultaneously, then etching is only carried out on the second groove so as to form the third groove, and thus a deep groove and a shallow groove are formed, so that influences imposed on the MOSFET device by photoetching alignment deviation can be avoided when the deep groove and the shallow groove are formed, the manufacturing process of the MOSFET device is optimized, the procedures are simplified, and the cost is reduced.", "author_names": [ "" ], "corpus_id": 140860552, "doc_id": "140860552", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Manufacturing method of MOSFET (Metal Oxide Semiconductor Field Effect Transistor) device", "venue": "", "year": 2015 }, { "abstract": "The invention relates to a method for preparing a SiC MOSFET (Metal Oxide Semiconductor Field Effect Transistor) grid oxide layer and belongs to the field of a SiC MOSFET device. The method comprises the following steps: generating a SiO2 grid oxide layer on a SiC epitaxial layer; annealing the grid oxide layer in a C12 environment at a temperature ranging from 500 1000 DEG C, preferably 700 800 DEG C; introducing mixed gas of C12 and inert gas at a preferable rate of 0.5 2 slm, wherein the annealing pressure is 100 1000mbar, and the retention time is 30 180 min. According to the method, C12 is used for annealing a SiO2 grid medium layer, so that oxygen vacancy tapped charges in the grid medium SiO2 layer can be removed, and the critical breakdown electric field and the voltage endurance capability of the SiO2 grid medium layer in the SiC MOSFET device can be improved.", "author_names": [ "" ], "corpus_id": 117435408, "doc_id": "117435408", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Method for preparing SiC MOSFET (Metal Oxide Semiconductor Field Effect Transistor) grid oxide layer", "venue": "", "year": 2015 }, { "abstract": "The invention relates to the technical field of communication, in particular to an MOSFET (metal oxide semiconductor field effect transistor) bridge circuit. The MOSFET bridge circuit comprises a potential extraction circuit, an MOS (metal oxide semiconductor) tube drive circuit, a first PMOS (P channel metal oxide semiconductor) tube, a second PMOS tube, a first NMOS (N channel metal oxide semiconductor) tube and a second NMOS tube, wherein the potential extraction circuit is connected with the MOS tube drive circuit; the MOS tube drive circuit is respectively connected with the first PMOS tube, the second PMOS tube, the first NMOS tube and the second NMOS tube. The MOSFET bridge circuit provided by the invention is simple in structure; large scale mass production is easy to achieve; power consumption can be lowered; the calorific value can be reduced.", "author_names": [ "" ], "corpus_id": 140965360, "doc_id": "140965360", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "MOSFET (metal oxide semiconductor field effect transistor) bridge circuit", "venue": "", "year": 2015 }, { "abstract": "The invention provides an MOSFET (Metal Oxide Semiconductor Field Effect Transistor) provided with a GeSn source and drain and a forming method thereof. The forming method comprises the following steps: providing a substrate of which the top is provided with a Ge layer; forming a gate stack or a fake gate on the substrate; forming openings of a source area and a drain area in both sides of the gate stack or the fake gate, and exposing the Ge layer out of the openings; injecting atoms, molecules, ions or plasmas containing Sn elements into the surface layer of the Ge layer, and forming a GeSn layer in the openings. By adopting the forming method of the MOSFET, a field effect transistor provided with the GeSn source and drain can be formed. Since the thicknesses of the GeSn source and drain are small, and the crystal quality is good, the transistor has high electric performance. Moreover, the method has the advantages of easiness, practicability and low cost.", "author_names": [ "" ], "corpus_id": 116754022, "doc_id": "116754022", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "MOSFET (Metal Oxide Semiconductor Field Effect Transistor) provided with GeSn source and drain and forming method thereof", "venue": "", "year": 2014 }, { "abstract": "The invention discloses a novel trench type MOSFET (metal oxide semiconductor field effect transistor) device and a manufacturing method thereof. A concave interface is formed between a body area and a semiconductor substrate, so that the part under source metal contact, of the body area is thinner than other parts of the body area. The most concave position E of the concave interface is positioned under the source metal contact so as to lead a reversed electric field to be gathered at the most concave position. A heavily doped region positioned under the source metal contact also can be formed in the body area so as to reduce the resistance. When the MOSFET is shut off, a reverse current is generated, flows through the heavily doped region from the most concave position and reaches the source metal contact, so that the influence of an equivalent parasitic transistor B on the shutoff of the MOSFET is reduced and the lower voltage drop is generated. In the novel trench type MOSFET device disclosed by the invention, the parasitic transistor is effectively controlled, and the UIS performance of the trench type MOSFET is improved.", "author_names": [ "" ], "corpus_id": 146459680, "doc_id": "146459680", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Trench type MOSFET (metal oxide semiconductor field effect transistor) device", "venue": "", "year": 2011 }, { "abstract": "The invention provides a manufacturing method of an MOSFET (metal oxide semiconductor field effect transistor) The manufacturing method is characterized in that a sacrificial side wall of amorphous carbon is removed by adopting oxygen or carbon dioxide plasma oxidation method to form a side wall hole; and the dielectric constant of the side wall hole is 1 and is only one seventh of a silicon nitride side wall, so that the capacitance between the grid and a contact plug of a source drain region can be obviously reduced, and the speed and the switching power consumption performance of a short grid length MOSFET device can be effectively improved. The manufacturing method provided by the invention has the advantages that the process is simple, the cost is saved, the formed side wall cavity can exist permanently, and the service life of the device can be prolonged.", "author_names": [ "" ], "corpus_id": 116605960, "doc_id": "116605960", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Manufacturing method of MOSFET (metal oxide semiconductor field effect transistor)", "venue": "", "year": 2011 }, { "abstract": "The invention discloses a semiconductor device comprising a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) device, and methods of manufacturing a MOSFET device. The MOSFET device comprises: a drain of a first doping type; a body of a second doping type, wherein the body is between the drain and a source; a gate above the body, wherein the source is at one side of the gate and the drain is at another side of the gate; and a recessed Field Oxide (recessed FOX) structure, wherein the recessed FOX structure is between the gate and a drift region vertically and wherein the recessed FOX structure is configured to make the drift region into a U shape. The structure increases the puncture voltage of the MOSFET, increases the electric density and has low cost.", "author_names": [ "" ], "corpus_id": 140339237, "doc_id": "140339237", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Semiconductor device comprising MOSFET (Metal Oxide Semiconductor Field Effect Transistor) device and methods of manufacturing MOSFET device", "venue": "", "year": 2012 }, { "abstract": "Disclosed is a high voltage MOSFET (metal oxide semiconductor field effect transistor) driving circuit which comprises a first high voltage switching circuit PMOSFET (positive metal oxide semiconductor field effect transistor) and a secondary high voltage switching circuit NMOSFET (negative metal oxide semiconductor field effect transistor) of a driving switch component and also comprises a first level displacement circuit, a secondary level displacement circuit, a first voltage distributing circuit, a secondary voltage distributing circuit, a first grid controlling circuit and a secondary grid controlling circuit; on main channels of the high voltage PMOSFET and the high voltage NMOSFET of the driving switch component, a voltage regulator diode is used for replacing an audion in the traditional high voltage MOSFET driving circuit, so that the static power consumption of the whole circuit is greatly reduced; and the voltage is directly distributed by a resistor, so as to ensure that the grid source interelectrode voltage between the high voltage PMOSFET and the high voltage NMOSFET of the driving switch component does not exceed the highest value of the grid source interelectrode voltage, therefore, the limit of the highest grid source interelectrode voltage is guaranteed, and the load regulation of the whole circuit can be effectively reduced.", "author_names": [ "" ], "corpus_id": 141159714, "doc_id": "141159714", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "High voltage MOSFET (metal oxide semiconductor field effect transistor) driving circuit", "venue": "", "year": 2010 }, { "abstract": "The invention discloses a method for producing a power MOSFET (metal oxide semiconductor field effect transistor) which comprises the following steps: respectively forming a drain region, a source region and a grid electrode of the power MOSFET; forming a grid contact hole of the grid electrode; and according to the depth of the grid contact hole, dividing the grid contact hole into at least two sections along the direction perpendicular to the drain region, and respectively etching each section so as to form the grid contact hole. The method provided by the invention has the advantage that the operation is simple; and through adjusting the proportional relationship between a first etching length and a second etching length, the balance between the power consumption and the etching effect is realized, which not only saves the energy sources and improves the production efficiency, but also improves yield and the reliability of and gate oxide.", "author_names": [ "" ], "corpus_id": 140529214, "doc_id": "140529214", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Method for producing power MOSFET (metal oxide semiconductor field effect transistor)", "venue": "", "year": 2010 }, { "abstract": "OBJECTIVES The objective of this study was to compare the performance of metal oxide semiconductor field effect transistor (MOSFET) technology dosemeters with thermoluminescent dosemeters (TLDs) (TLD 100; Thermo Fisher Scientific, Waltham, MA) in the maxillofacial area. METHODS Organ and effective dose measurements were performed using 40 TLD and 20 MOSFET dosemeters that were alternately placed in 20 different locations in 1 anthropomorphic RANDO((r) head phantom (the Phantom Laboratory, Salem, NY) The phantom was exposed to four different CBCT default maxillofacial protocols using small (4 x 5 cm) to full face (20 x 17 cm) fields of view (FOVs) RESULTS The TLD effective doses ranged between 7.0 and 158.0 uSv and the MOSFET doses between 6.1 and 175.0 uSv. The MOSFET and TLD effective doses acquired using four different (FOV) protocols were as follows: face maxillofacial (FOV 20 x 17 cm) (MOSFET, 83.4 uSv; TLD, 87.6 uSv; 5% teeth, upper jaw (FOV, 8.5 x 5.0 cm) (MOSFET, 6.1 uSv; TLD, 7.0 uSv; 14% tooth, mandible and left molar (FOV, 4 x 5 cm) (MOSFET, 10.3 uSv; TLD, 12.3 uSv; 16% and teeth, both jaws (FOV, 10 x 10 cm) (MOSFET, 175 uSv; TLD, 158 uSv; +11% The largest variation in organ and effective dose was recorded in the small FOV protocols. CONCLUSIONS Taking into account the uncertainties of both measurement methods and the results of the statistical analysis, the effective doses acquired using MOSFET dosemeters were found to be in good agreement with those obtained using TLD dosemeters. The MOSFET dosemeters constitute a feasible alternative for TLDs for the effective dose assessment of CBCT devices in the maxillofacial region.", "author_names": [ "Juha Koivisto", "Dirk Schulze", "Jan Wolff", "Dennis Rottke" ], "corpus_id": 34125416, "doc_id": "34125416", "n_citations": 19, "n_key_citations": 1, "score": 0, "title": "Effective dose assessment in the maxillofacial region using thermoluminescent (TLD) and metal oxide semiconductor field effect transistor (MOSFET) dosemeters: a comparative study.", "venue": "Dento maxillo facial radiology", "year": 2014 } ]

[ { "abstract": "This paper examines the potential impact of artificial intelligence (A.I. on economic growth. We model A.I. as the latest form of automation, a broader process dating back more than 200 years. Electricity, internal combustion engines, and semiconductors facilitated automation in the last century, but A.I. now seems poised to automate many tasks once thought to be out of reach, from driving cars to making medical recommendations and beyond. How will this affect economic growth and the division of income between labor and capital? What about the potential emergence of \"singularities\" and \"superintelligence,\" concepts that animate many discussions in the machine intelligence community? How will the linkages between A.I. and growth be mediated by firm level considerations, including organization and market structure? The goal throughout is to refine a set of critical questions about A.I. and economic growth and to contribute to shaping an agenda for the field. One theme that emerges is based on Baumol's \"cost disease\" insight: growth may be constrained not by what we are good at but rather by what is essential and yet hard to improve.", "author_names": [ "Philippe Aghion", "Benjamin F Jones", "Charles I Jones" ], "corpus_id": 26299957, "doc_id": "26299957", "n_citations": 146, "n_key_citations": 12, "score": 2, "title": "Artificial Intelligence and Economic Growth", "venue": "", "year": 2017 }, { "abstract": "Artificial Intelligence (AI) is performing an increasingly significant role in everyday life as it has the potential to increase the efficiency of productivity and boost the economy. While the technology world is advancing, the mortality rate and the fertility rate of people are declining. These demographic trends have urged many countries to pay a concern to the apparent problems associated with the aging society like the shrinking proportion of the working age population, which in turn can bring about the decline in productivity and the national economic slow down. Hence, we aim to investigate the relationship among investment in AI, Aging society, and Economic growth in three advanced countries, namely China, Japan, and the U.S. using the Copula based simultaneous equations model. The results obtained from the model can conform to our hypothesis only in the case of China and Japan. However, the result of the U.S. is deviated from the hypothesis but challenging.", "author_names": [ "Kantika Khanthawithoon", "Paravee Maneejuk", "Woraphon Yamaka" ], "corpus_id": 224858921, "doc_id": "224858921", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Analyzing the Relationship Among Aging Society, Investment in Artificial Intelligence and Economic Growth", "venue": "", "year": 2020 }, { "abstract": "This paper describes the use of five machine learning methods for predicting economic growth based on a countryaEUR(tm)s attributes and presents a comparison of their prediction accuracy. The methods used are four neural network (NN) methods with different activation functions, and eXtreme Gradient Boosting (XGBoost) Their performance is compared in terms of their ability to predict the economic growth rate using three measures (prediction accuracy rate, area under the curve (AUC) value, and F score) The results obtained can be summarized as follows: 1) XGBoost outperforms the NNs in terms of prediction accuracy and F score for original data; 2) data standardization enhances the reliability of NNs, improving their prediction accuracy, AUC value, and F score; 3) XGBoost has smaller standard deviation of prediction accuracy rate than that of NNs; and 4) \"Political institution\" \"Investment and its composition\" \"Colonial history\" and \"Trade\" are important factors for cross country economic growth.", "author_names": [ "Shigeyuki Hamori", "Takahiro Kume" ], "corpus_id": 217065814, "doc_id": "217065814", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Artificial Intelligence And Economic Growth", "venue": "", "year": 2018 }, { "abstract": "", "author_names": [ "Patrick Francois" ], "corpus_id": 196004780, "doc_id": "196004780", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Comment on \"Artificial Intelligence and Economic Growth\"", "venue": "", "year": 2018 }, { "abstract": "", "author_names": [ "Michael McAleer" ], "corpus_id": 210172221, "doc_id": "210172221", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Artificial Intelligence and Economic Growth*", "venue": "", "year": 2018 }, { "abstract": "The economic impact of Articial Intelligence (AI) is studied using a (semi) endogenous growth model with two novel features. First, the task approach from labor economics is reformulated and integrated into a growth model. Second, the standard representative household assumption is rejected, so that aggregate demand restrictions can be introduced. With these novel features it is shown that (i) AI automation can decrease the share of labor income no matter the size of the elasticity of substitution between AI and labor, and (ii) when this elasticity is high, AI will unambiguously reduce aggregate demand and slow down GDP growth, even in the face of the positive technology shock that AI entails. If the elasticity of substitution is low, then GDP, productivity and wage growth may however still slow down, because the economy will then fail to benefit from the supply side driven capacity expansion potential that AI can deliver. The model can thus explain why advanced countries tend to experience, despite much AI hype, the simultaneous existence of rather high employment with stagnating wages, productivity, and GDP.", "author_names": [ "Thomas Gries", "Wim Naude" ], "corpus_id": 221817016, "doc_id": "221817016", "n_citations": 5, "n_key_citations": 1, "score": 0, "title": "Artificial Intelligence, Income Distribution and Economic Growth", "venue": "", "year": 2020 }, { "abstract": "The economic impact of Artificial Intelligence (AI) is studied using a (semi) endogenous growth model with two novel features. First, the task approach from labor economics is reformulated and integrated into a growth model. Second, the standard representative household assumption is rejected, so that aggregate demand restrictions can be introduced. With these novel features it is shown that (i) AI automation can decrease the share of labor income no matter the size of the elasticity of substitution between AI and labor, and (ii) when this elasticity is high, AI will unambiguously reduce aggregate demand and slow down GDP growth, even in the face of the positive technology shock that AI entails. If the elasticity of substitution is low, then GDP, productivity and wage growth may however still slow down, because the economy will then fail to benefit from the supply side driven capacity expansion potential that AI can deliver. The model can thus explain why advanced countries tend to experience, despite much AI hype, the simultaneous existence of rather high employment with stagnating wages, productivity, and GDP.", "author_names": [ "Wim Naude" ], "corpus_id": 221368215, "doc_id": "221368215", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "www.econstor.eu Artificial Intelligence, Income Distribution and Economic Growth", "venue": "", "year": 2020 }, { "abstract": "This study presents a new hybrid algorithm for forecasting economic growth using indicators of knowledge based economy (KBE) The algorithm consists of three steps, namely preprocessing, processing, and postprocessing. Preprocessing consists of principal component analysis and reproduction algorithm, which are used to decrease the number of variables and increase the volume of data. Economic growth is predicted during processing using multilayer perceptron (MLP) adaptive neuro fuzzy inferences system, and gene expression programming (GEP) The variables are added separately to the process. The best model is selected during the postprocessing step to forecast economic growth. GEP model is used to forecast unique indicators. The last step involves substitution of forecasted indicators in the best model. In this study, the KBE indicators of Iran from 1993 to 2013 are predicted in the processing step. The MLP model is used, which includes four indicators, namely technological foundation, structure of trained manpower, export and trademark, and employee. Indicators are also forecasted using the GEP model between 2013 and 2020. The results are used to estimate economic growth between forecasting periods. A self organizing map is used to recognize relationships between variables. The results show the efficiency of the algorithm in multivariate forecasting.", "author_names": [ "Mohsen Ahmadi", "Saeid Jafarzadeh-Ghoushchi", "Rahim Taghizadeh", "Abbas Sharifi" ], "corpus_id": 199491627, "doc_id": "199491627", "n_citations": 21, "n_key_citations": 1, "score": 0, "title": "Presentation of a new hybrid approach for forecasting economic growth using artificial intelligence approaches", "venue": "Neural Computing and Applications", "year": 2019 }, { "abstract": "With the Chinese government s attention to the artificial intelligence industry, the Chinese government has invested a lot in it recently. Of course,", "author_names": [ "Yu gang He" ], "corpus_id": 213968811, "doc_id": "213968811", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The Effect of Artificial Intelligence on Economic Growth: Evidence from Cross Province Panel Data", "venue": "", "year": 2019 }, { "abstract": "", "author_names": [ "Yu gang He" ], "corpus_id": 203989994, "doc_id": "203989994", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "The Importance of Artificial Intelligence to Economic Growth", "venue": "Korean Artificial Intelligence", "year": 2019 } ]

[ { "abstract": "A camera unit is mountable on rear of motorcycle. The camera unit includes a single chip image sensor, such as a colour complementary metal oxide semiconductor image sensor, and includes an attaching unit that is structured to allow the camera unit to be attached to an existing structure of the motorcycle. The camera unit further includes a transmit unit to allow transmission of a signal representative of captured images and a receive unit to receive control signals to control parameters associated with the camera unit, thereby allowing the remote unit to control parameters of the camera unit, such as exposure, gain, white balance, colour saturation, brightness. The camera unit can be of a small size and weight, and can be completely integrated on a single chip, thereby minimizing intrusiveness to the helmet wearer. The vehicle alert system project focuses on cooperative alert services based on timely and reliable communication under the challenging circumstances pertaining to a highly mobile vehicular network. Keywords Single Chip Image Sensor, White Balance, Helmet Wearer, Colour Saturation. I.INTRODUCTION \"Many researches and invention are carried out for the improvement in the bike technology which is known as smart bike concept or superbike concept.\" This project is based on super bike concept in which we are going to improve the driving assistance using rear camera and ultrasonic sensors. This concept is derived from four parking system. Using this concept, we can eliminate side mirrors of the motorcycle, this causes improvement in aerodynamic shape of the motorcycle and increases the performance of motorcycle.The rear view camera is a new robust and smart video driver assistance for automotive applications. This camera system able to transmit the video signal within a distance around 20 meters wirelessly and reliable. It is an embedded system based on a very low latency video encoder and designed to be extremely fast, cheap in production, reliable and safe against attacks and interference. The total signal delay is less than 40 meters. Coding time is around 10meters. Technological advancement has led the advancement and prevalence of wireless sensor networks in many of man's activities. The WSN consist of numerous low costing sensor nodes that are organized to establish an ad hoc network via wireless communication module that is equipped on the nodes. The sensor nodes are equipped with different sensors. This rear parking sensor system is designed to assist the driver by providing an alert when the vehicle is travelling toward a nearby object. Never rely solely on this product to ensure the area is clear of children and obstructions. This product is not intended to replace existing safety procedures, but rather to add an additional safety tool for your vehicle. Vehicle Alert System is a project concerning the areas of cooperating embedded systems, vehicular ad hoc networks, wireless sensor networks and wireless digital communication. A communication system, wireless or wired, has some sort of communication stack containing rules on how the actual communication should take place. These rules are encapsulated in protocols and can be organized into different layers stacked above each other.In the sewer inspection system under development and testing this system is mounted in the rear portion on vehicle which will move inside the fully or semi filled sewer pipeline. The system will compute the distance of obstacle or blockage store it and also communicate the distance or location of the obstacle or blockage to the control station above ground.", "author_names": [ "Karande Nita", "Tambe Kirti", "Bhalerao Omkar", "Hredeya Mishra" ], "corpus_id": 214754940, "doc_id": "214754940", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Two Wheeler Guidance System Utilizing Ultrasonic Sensor, Rear View Camera and Accident Alert System", "venue": "", "year": 2019 }, { "abstract": "Spatial disorientation continues to be one of the most costly problems in military aviation, as measured by both life and equipment loss. The unique Helmet Mounted Display (HMD) centric interface within 5 generation aircraft has the potential to increase tactical capability when compared to previous similar role aircraft. This study investigated the addition of off axis ownship attitude information within the HMD field of view when the operator looks away from the virtual Head Up Display (vHUD) In some 5 generation aircraft, traditional HUD symbology is presented via the HMD as there is no aircraft fixed combiner. In some instances, the only attitude information included via the HMD is part of the vHUD symbology and is only available when the operator looks forward. For this study, a comparison was performed between a baseline representative symbology design and two other interfaces which included variations of offboresight attitude information symbology. Air to ground tactical tasks of varying complexity were performed in live flight by evaluation pilots seated in the rear cockpit of an L 29 aircraft while donning a 5 generation representative HMD system. In addition to the HMD symbology, the visual scene presented was a virtual depiction of a mountainous terrain area. The real outside world was occluded by an opaque hood affixed to the canopy glass. Qualified pilots (n 10) participated in the study and each flew three approximately one hour flights. Data collection included quantitative performance, physiological response, and subjective feedback, and preliminary results are presented here.", "author_names": [ "Thomas Schnell", "Christopher Patrick Reichlen", "Christoph Reuter", "Eric E Geiselman", "J Knox", "Henry Williams" ], "corpus_id": 117386213, "doc_id": "117386213", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A Comparison of Helmet Mounted Display Symbologies During Live Flight Operational Tasks", "venue": "", "year": 2017 }, { "abstract": "In order to meet the demands of Helmet Mounted Display (HMD) with large field of view, high image quality and colorful display, a modified optical system for HMD is proposed. The system, with a miniature color LCD as the image source, adopts a hybrid refractive/diffractive singlet in place of the doublet. The chromatic aberration and wavefront aberration of the optical system can be eliminated with negative dispersion coefficient and power of arbitrary phase modulation of the binary element, respectively. The image source forms an intermediate image near the beam splitter to enlarge the field of view; the exit pupil forms an intermediate image between the front and rear elements of the relay optics to reduce the diameter of the optical system and enlarges the diameter of the exit pupil. The spherical combiner projects the collimated beam from beam splitter into human eyes, which eliminates eyestrain caused by repeatedly observing video images and external images with different focal lengths. The vertical axis chromatic aberration of the system is less than 42mm in visible light band and its field of view enlarges to 40deg (horizontal)x30deg(vertical) Its resolution has approached the minimal resolving capability of human eye. In addition, the aperture is less than 46mm and weight is reduced by 47% than that of the existing perspective HMD.", "author_names": [ "Lu Zhen-wu" ], "corpus_id": 123284717, "doc_id": "123284717", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design of the optical system for a see through refractive/diffractive hybrid helmet mounted display", "venue": "", "year": 2005 }, { "abstract": "Road accidents frequently happen nowadays. The majority of the fatality accident involves motorcyclist and most of them encounter in head injuries. Lack of peripheral vision is one of the factors that affect the road accident or crashes. Although there are helmets with rear view mirrors that currently exist in the market provides good improvement on road accident, but limited usage of the helmet for motorcycle user due to the high price of the helmet. The price of the helmet are not affordable for poor motorcyclist. Thus, a low cost helmet with rear vision features made in sustainability element is proposed in this project. Market analysis is first carried out to gain the voice of target customer before the concept generated. Followed by numerous quality tools and strategic selecting tools like HOQ, AHP method, CES software, SolidWorks and others are used for giving a successful portfolio for further development of the product. HOQ method is adopted to determine the prioritized engineering target to be met by the new helmet; AHP method is used to select the best concept which generated via hand sketching; SolidWorks applied for 3D drawing and analysis of the new helmet. FEA analysis is applied to testing the workable and safety of the design. While Drop test analysis is used to analyze the impact of the rear view helmet after collision happen. Furthermore, prototyping is carried out by using the FDM machine, Up Plus 3D printer for visualizing and testing purpose. Last but not least, the testing of the periscope concept in the rear view mechanism is tested by laser pen. The prototype is worked as intended, i.e. the user can see the back view while using this periscope attachment device.", "author_names": [ "Ai Xin Ng" ], "corpus_id": 116356012, "doc_id": "116356012", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design And Development Of Broader Viewing Angle Device For Motorcyclist To Improve Safety", "venue": "", "year": 2016 }, { "abstract": "FIELD: personal use articles. SUBSTANCE: invention relates to devices for protection of human head and deals with a helmet with a projection system. The helmet contains a controller, a video camera, a data receiving/transmitting unit, a speech recognition unit, a unit for determination of the helmet spatial position and an optical system. The optical system includes an image generator based on a scanning laser module, a scanner lens, a unit for exit pupil diameter magnification, a projection optical system and the helmet transparent shield (visor) through which one simultaneously observes the surrounding situation and views graphical information being transmitted. The projection optical system consists of a nonaxisymmetric component, a flat mirror and an axisymmetric lens. The projection optical system is designed so that to enable receipt of control commands and information from the speech recognition unit and the unit for determination of the helmet spatial position. The data receiving/transmitting unit is designed so that to enable data exchange via wireless networks. EFFECT: improvement of image quality and simplification of control of the helmet systems. 4 cl, 2 dwg", "author_names": [ "Andrei Borisovich Artishchev", "Mikhail Abramovich Gan", "Aleksandr Alekseevich Starkov", "Sergei Anatol'evich Larionov" ], "corpus_id": 64738721, "doc_id": "64738721", "n_citations": 1, "n_key_citations": 1, "score": 0, "title": "Helmet with projection system", "venue": "", "year": 2012 }, { "abstract": "Spatial and temporal data derived from eye movements, compiled while the human eye observes geospatial imagery, retain meaningful and usable information. When human perceives the stereo effect, the virtual three dimensional (3D) model resulting from eye brain interaction is generated in the mind. If the eye movements are recorded while the virtual model is observed, it is possible to reconstruct a 3D geometrical model almost identical to the one generated in the human brain. Information obtained from eye movements can be utilized in many ways for remote sensing applications such as geospatial image analysis and interpretation. There are various eyetracking systems available on the market; however, none of them is designed to work with stereoscopic imagery. We explore different approaches and designs of the most suitable and non intrusive scheme for stereoscopic image viewing in the eye tracking systems to observe and analyze 3D visual models. The design of the proposed system is based on the optical separation method, which provides visually comfortable environment for perception of stereoscopic imagery. A proof of concept solution is based on multiple mirror lens assembly that provides a significant reduction of geometrical constrains in eye frame capturing. Two projected solutions: for wide angle of viewing and helmet integrated eye tracker are also discussed here.", "author_names": [ "Aleksandr V Sergeyev", "Eugene Levin", "Michael C Roggemann", "Gennady Gienko" ], "corpus_id": 120316397, "doc_id": "120316397", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design of the stereoscopic eye tracking system for quantitative remote sensing applications", "venue": "Optical Engineering Applications", "year": 2008 }, { "abstract": "A novel simulator display system is described. The display consists of a full field of view rear screen projection display and a narrow field of view high resolution helmet mounted display (HMD) The HMD is worn by the pilot within the projection display. The virtual image of the HMD is thus superimposed upon the real image of the projection display. This hybrid approach to building a wide field of view display takes advantage of the beneficial aspects of both projection displays and HMDs. The result is a low cost total field of view display with high resolution. Several system design problems arise in the integration of the HMDwith the projection display. These issues are discussed, and include: the design of an HMD eyepiece with minimal obtrusiveness, visual blending of the HMD imagery with the projected imagery, and timing and perspective issues relating to the computer generated imagery presented by both the HMD and the projection display.", "author_names": [ "George R Kelly", "Martin Shenker", "Paul E Weissman" ], "corpus_id": 120527685, "doc_id": "120527685", "n_citations": 7, "n_key_citations": 0, "score": 1, "title": "Helmet mounted area of interest", "venue": "Defense, Security, and Sensing", "year": 1992 }, { "abstract": "The optical design, fabrication and performance of a solid Schmidt prism used for relaying an optical signal or image to the eye while simultaneously providing the viewer with the capability to see through to the outside world is described. It can be either of solid glass or plastic construction like a prism, or made of separate components. The novel aspect of this approach over previous designs is folding the system between the image and the Schmidt mirror as opposed to folding it at the image itself. This allows for a more compact design. The solid glass approach extends the apparent field of view to the viewer through refraction at the glass to air interface. If the spherical reflector of the Schmidt is rendered opaque, the viewer will only see the information provided by the optical stimulus. If partially reflective, the viewer can augment real world scenes with computerized symbology superimposed in the visual field. The stimulus may be either a high resolution CRT or a flat panel liquid crystal display (LCD)<ETX>", "author_names": [ "Paul K Manhart", "R Malcolm", "John G Frazee" ], "corpus_id": 30288581, "doc_id": "30288581", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "\"Augeye\" a compact, solid Schmidt optical relay for helmet mounted displays", "venue": "Proceedings of IEEE Virtual Reality Annual International Symposium", "year": 1993 }, { "abstract": "A low cost helmet mounted stereoscopic color viewing system designed for field testing teleoperator tasks is described. A stereo camera pair was mounted on a helmet to allow testing of a helmet mounted display with real time video input. The display consisted of a pair of LCD color monitors viewed through a modified Wheatstone mirror system. The components were arranged on a stable platform that was attached to a hard plastic helmet. The helmet weight (9.5 pounds) was supported by a modified backpack. This backpack also contained support electronics and batteries. Design, construction, and evaluation tests of this viewing system are discussed.", "author_names": [ "Robert E Cole", "Curtis S Ikehara", "John O Merritt" ], "corpus_id": 110282054, "doc_id": "110282054", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Low cost helmet mounted camera/display system for field testing teleoperator tasks", "venue": "Electronic Imaging", "year": 1992 }, { "abstract": "The goal of the cathode ray tube (CRT) helmet mounted display (HMD) project was development and demonstration of a low cost monochrome display incorporating see through optics. The HMD was also to be integrable with a variety of image generation systems and suitable for use with low cost cockpit trainers and night vision goggles (NVG) training applications. A final goal for the HMD was to provide a full field of regard (FOR) using a head tracker system. The resultant HMD design included two 1 inch CRTs used with a simple optical design of beam splitters and spherical mirrors. The design provides for approximately 50% transmission and reflectance capabilities for observing the 30 degree(s) vertical X 40 degree(s) horizontal biocular instantaneous field of view visual image from a graphic image generator system. This design provides for a theoretical maximum of 10.8% of the CRT image source intensity arriving at the eye. Initial tests of image intensity at the eye for an average out the window scene have yielded 12 to 13 Foot Lamberts with the capability of providing approximately 130 Foot Lamberts. Invoking a software 'own ship' mask to 'blackout' the visual image, the user can monitor 'in cockpit' instrumentation utilizing the see through characteristics of the optics. The CRTs are operated at a TV line rate with a modulation transfer function (MTF) of approximately 65% The small beam spot size and the high MTF provide for an enhanced image display. The display electronics are designed to provide a monochrome video picture based on an RS170 video input.", "author_names": [ "Roger Leinenwever", "Leonard G Best", "Bryce J Ericksen" ], "corpus_id": 123524384, "doc_id": "123524384", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Low cost monochrome CRT helmet display", "venue": "Defense, Security, and Sensing", "year": 1992 } ]

[ { "abstract": "This paper provides design and development details of the generation of bipolar High Voltage (HV) square wave pulses for the excitation of low frequency ultrasonic transducers. Such a circuit is required for the purpose of ultrasonic inspection of components, particularly where high energy is required to insonify the attenuative medium, such as concrete. A HV 350 V) square wave pulse has been generated by an ultrafast complementary Metal Oxide Semiconductor Field Effect Transistor (MOSFET) pair, which is driven by high speed MOSFET drivers. The generated bipolar square wave pulse has been utilized to energize a 108 kHz ultrasonic transducer to operate in the pulse echo mode for the evaluation of a concrete test block. The receiver amplifier filters the received low amplitude echo signals, which are reflected back from a discontinuity, and amplifies further for signal to noise ratio enhancement. The pulser board designed has been tested and evaluated for its functionality to measure ultrasonic velocity in the highly attenuative concrete medium up to a depth of 1 m. The measured value of acoustic velocity was compared with the value obtained from the commercially available ultrasonic pulse velocity instrument, and the values obtained are within 5%", "author_names": [ "Harshit Jain", "Eaglekumar G Tarpara", "Vikram Patankar" ], "corpus_id": 222168144, "doc_id": "222168144", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Design and development of ultrasonic bipolar square wave pulser for non destructive testing of concrete structures.", "venue": "The Review of scientific instruments", "year": 2020 }, { "abstract": "The health state of concrete is deteriorating during its service. Nonlinear ultrasonic detection based on the amplitude of the fundamental and the second harmonic is considered to be a powerful tool for the discovery of the microcrack in concrete. However, the research on processing the nonlinear ultrasonic signal is still insufficient. In order to highlight the real frequency domain components in the nonlinear ultrasonic signal, wavelet and ensemble empirical mode decomposition (EEMD) were joined to denoise the numerical and measured signal. The optimal wavelet base and the decomposition level were determined by the signal to noise ratios (SNRs) Then, the wavelet threshold denoising signal was decomposed by EEMD, omitting the high frequency components and ultimately achieving the desired denoising effect. The denoising result of the test signals demonstrates that this method is effective in denoising the details of the ultrasonic signal and improving the reliability and adaptability of the nonlinear ultrasonic testing. In this experiment, the concrete with the microcrack was tested by linear and nonlinear ultrasonic methods. Based on the variation regularity of the nonlinear ultrasonic coefficient and velocity we can conclude that the nonlinear ultrasonic parameter is more sensitive to the microcrack in concrete than the traditional wave velocity The nonlinear ultrasonic testing can be an important supplement to the current nondestructive testing technique of the concrete.", "author_names": [ "Zhichao Nie", "Kui-Fang Wang", "Mingjie Zhao" ], "corpus_id": 55326647, "doc_id": "55326647", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Application of Wavelet and EEMD Joint Denoising in Nonlinear Ultrasonic Testing of Concrete", "venue": "", "year": 2018 }, { "abstract": "Based on the urban shantytown renovation project in Hongguang Town, Helan County, Ningxia, in Northwest China, the influence of fly ash and silica fume admixture on the mechanical properties of Self compacting Concrete (SCC) was tested and analyzed in this work. The experimental tests including compressive strength, splitting strength, triaxial strength and an ultrasonic nondestructive test. Furthermore, the Back Propagation (BP) neural network algorithms were established. The results show that there is an obvious difference between the development law of compressive strength of SCC and that of ordinary concrete. The splitting pressure ratio of SCC is 1/10 to 1/8, while that of ordinary concrete is 1/13 to 1/10. Moreover, the peak strain, peak stress and initial stiffness of SCC increase with the increase of the confining pressure when compressed from three directions. In addition, the ultrasonic amplitude of SCC can reflect the changing laws of its compressive strength. As a conclusion, the addition of fly ash and silica fume increases the splitting pressure ratio of SCC. More importantly, the compressive strength formula for SCC with silica fume and a low content of fly ash is proposed, and the model equation between the amplitude and compressive strength is given. This study provides a reference for the mixture ratio of fly ash and silica fume in the application of SCC.", "author_names": [ "Hongbo Li", "Hao Yue Sun", "Juncang Tian", "Qiuning Yang", "Qingqing Wan" ], "corpus_id": 195401946, "doc_id": "195401946", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Mechanical and Ultrasonic Testing of Self Compacting Concrete", "venue": "Energies", "year": 2019 }, { "abstract": "Ultrasonic testing analysis is a crucial scientific component during the process and interpretation of the ultrasonic detection signal. Focusing on the ultrasonic testing characteristics, the time invariant spectral analysis method cannot meet the processing requirements of the detection signal fully. Thus, S transform, the time varying analysis method, was introduced into the ultrasonic testing data processing of the concrete structure. The acoustic wave phase velocity was derived based on the spectrum analysis, and the S transform time frequency analysis method was established. Finally, based on the method of concrete experimental data set, studies show that the frequency energy spectrum with S transform can realize flexible and effective identification of defects in the concrete structure. Definitely, this analysis method can significantly improve the resolution and practicality of ultrasonic testing.", "author_names": [ "Juncai Xu", "Hai Wei" ], "corpus_id": 209986207, "doc_id": "209986207", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Ultrasonic Testing Analysis of Concrete Structure Based on S Transform", "venue": "Shock and Vibration", "year": 2019 }, { "abstract": "&NA; The use of nonlinear acoustic techniques in solids consists in measuring wave distortion arising from compliant features such as cracks, soft intergrain bonds and dislocations. As such, they provide very powerful nondestructive tools to monitor the onset of damage within materials. In particular, a recent technique called dynamic acousto elasticity testing (DAET) gives unprecedented details on the nonlinear elastic response of materials (classical and non classical nonlinear features including hysteresis, transient elastic softening and slow relaxation) Here, we provide a comprehensive set of linear and nonlinear acoustic responses on two prismatic concrete specimens; one intact and one pre compressed to about 70% of its ultimate strength. The two linear techniques used are Ultrasonic Pulse Velocity (UPV) and Resonance Ultrasound Spectroscopy (RUS) while the nonlinear ones include DAET (fast and slow dynamics) as well as Nonlinear Resonance Ultrasound Spectroscopy (NRUS) In addition, the DAET results correspond to a configuration where the (incoherent) coda portion of the ultrasonic record is used to probe the samples, as opposed to a (coherent) first arrival wave in standard DAET tests. We find that the two visually identical specimens are indistinguishable based on parameters measured by linear techniques (UPV and RUS) On the contrary, the extracted nonlinear parameters from NRUS and DAET are consistent and orders of magnitude greater for the damaged specimen than those for the intact one. This compiled set of linear and nonlinear ultrasonic testing data including the most advanced technique (DAET) provides a benchmark comparison for their use in the field of material characterization. HighlightsThe results from a suite of linear and nonlinear ultrasonic techniques are compared.Dynamic Acousto Elastic Testing (DAET) with a coda wave probe is presented.The retrieved non log(t) recovery at early times provides complementary information.", "author_names": [ "Parisa Shokouhi", "Jacques Riviere", "Colton R Lake", "Pierre-Yves Le Bas", "Timothy Ulrich" ], "corpus_id": 34913630, "doc_id": "34913630", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Dynamic acousto elastic testing of concrete with a coda wave probe: comparison with standard linear and nonlinear ultrasonic techniques", "venue": "Ultrasonics", "year": 2017 }, { "abstract": "This paper discusses the possibility of studying composite materials by non destructive laser ultrasonic testing technique. Concrete samples and carbon epoxy composites were examined, defects located and elastic wave velocities measured. The internal structure of the samples was visualized in 2D images.", "author_names": [ "Alexander Kravcov", "Pavel Svoboda", "Adam Konvalinka", "Elena Cherepetskaya", "Alexsander A Karabutov", "Dmitry Vladimirovich Morozov", "I A Shibaev" ], "corpus_id": 138635620, "doc_id": "138635620", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Laser Ultrasonic Testing of the Structure and Properties of Concrete and Carbon Fiber Reinforced Plastics", "venue": "", "year": 2016 }, { "abstract": "Abstract The ultrasonic fatigue testing method has been further developed to perform cyclic compression tests with concrete. Cylindrical specimens vibrate in resonance at a frequency of approximately 20 kHz with superimposed compressive static loads. The high testing frequency allows time saving investigations in the very high cycle fatigue regime. Fatigue tests were carried out on \"Concrete 1\" (compressive strength fc 80 MPa) and \"Concrete 2\" (fc 107 MPa) under purely compressive loading conditions. Experiments at maximum compressive stresses of 0.44 fc (Concrete 1) and 0.38 fc (Concrete 2) delivered specimen failures above 109 cycles, indicating that no fatigue limit exists for concrete below one billion load cycles. Resonance frequency, power required to resonate the specimen and second order harmonics of the vibration are used to monitor fatigue damage in situ. Specimens were scanned by X ray computed tomography prior to and after testing. Fatigue cracks were produced by ultrasonic cycling in the very high cycle fatigue regime at interfaces of grains as well as in cement. The possibilities as well as limitations of ultrasonic fatigue testing of concrete are discussed.", "author_names": [ "Ulrike Karr", "Reinhard Schuller", "Michael Fitzka", "Andreas Denk", "Alfred Strauss", "Herwig Mayer" ], "corpus_id": 136288760, "doc_id": "136288760", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Very high cycle fatigue testing of concrete using ultrasonic cycling", "venue": "", "year": 2017 }, { "abstract": "This paper presents the results of preliminary laboratory testing of early age concrete properties using disposable, embedded ultrasonic sensors. These tests were carried out during the development of a field system for monitoring the early age physical properties in concrete and shotcrete. The design is particularly suitable for applications in Fibre Reinforced Shotcrete (FRS) commonly used for ground support in underground mine tunnels in Australia, where the determination of early age properties is critical for establishing safe re entry times. The embedded system used in these experiments comprises a pair of piezoelectric transducers mounted to an open frame, which is designed to hold them within the concrete at a fixed offset separation. The probe is implanted at the time of placement, and connected via wire leads to an external control system. The implanted transducers are configured to excite longitudinal (P) waves, at a nominal resonance frequency of 40 kHz, and P wave transmission is detectable soon after the initial set time. The data presented herein includes evolution of early age P wave velocity. This data is compared to conventional unconfined compressive strength (UCS) and dynamic (low strain) elastic modulus, as specified in ASTM C215, for equivalent batches and curing conditions. The embedded P wave measurement is functionally equivalent to the conventional dynamic modulus testing procedure, and these results may be further used to infer UCS during the early stages of hydration. The ability to perform in situ, real time, nondestructive testing offers significant advantages to the safe and efficient use of FRS in underground mining applications.", "author_names": [ "Alexander Gibson", "Daniela Ciancio" ], "corpus_id": 138404824, "doc_id": "138404824", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Early Age Ultrasonic Testing of Concrete and Shotcrete using Embedded Sensors", "venue": "", "year": 2013 }, { "abstract": "", "author_names": [ "Jason Maximino C Ongpeng", "Andres Oreta", "Sohichi Hirose" ], "corpus_id": 116643949, "doc_id": "116643949", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Characterization of Damage Using Ultrasonic Testing on Different Types of Concrete", "venue": "", "year": 2018 }, { "abstract": "Synopsis Ultrasonic testing of a reinforced concrete member by means of the Pundit apparatus is affected by the steel bars embedded in the concrete. An investigation of the effects of the reinforcement has been made, using the bar diameter and the concrete strength as the variables. It is found that the steel bar appears to act compositely with the surrounding concrete in transmitting ultrasonic pulses. The effective pulse velocity is somewhat between the pulse velocities in the two separate media, and varies with the diameter of the bar and the pulse velocity in the concrete. An empirical formula for the effective pulse velocity is proposed. On the basis of this formula and further theoretical consideration, the zone of steel influence is defined. A correction factor is derived whereby the measured pulse velocity in a concrete steel medium is adjusted to give the pulse velocity in the plain concrete.", "author_names": [ "H W Chung" ], "corpus_id": 108513167, "doc_id": "108513167", "n_citations": 26, "n_key_citations": 2, "score": 0, "title": "Effects of embedded steel bars upon ultrasonic testing of concrete", "venue": "", "year": 1978 } ]

[ { "abstract": "We report on a device to electronically stabilize the optical injection lock of a semiconductor diode laser. Our technique uses as discriminator the peak height of the laser's transmission signal on a scanning Fabry Perot cavity and feeds back to the diode current, thereby maintaining maximum optical power in the injected mode. A two component feedback algorithm provides constant optimization of the injection lock, keeping it robust to slow thermal drifts and allowing fast recovery from sudden failures such as temporary occlusion of the injection beam. We demonstrate the successful performance of our stabilization method in a diode laser setup at 399 nm used for laser cooling of Yb atoms. The device eases the requirements on passive stabilization and can benefit any diode laser injection lock application, particularly those where several such locks are employed.", "author_names": [ "Brendan Saxberg", "Benjamin Plotkin-Swing", "Subhadeep Gupta" ], "corpus_id": 44501745, "doc_id": "44501745", "n_citations": 9, "n_key_citations": 1, "score": 1, "title": "Active stabilization of a diode laser injection lock.", "venue": "The Review of scientific instruments", "year": 2016 }, { "abstract": "A gain switched, single frequency titanium sapphire laser for atmospheric humidity measurements using the differential absorption lidar technique operating in the 820 nm wavelength region is described. The laser is pumped by a frequency doubled, flashlamp pumped Nd:YAG laser at a repetition rate of 50 Hz and injection seeded by two external cavity diode lasers. The system yields pulses with an energy of 15 mJ and high spectral purity. We describe a novel active injection locking technique that avoids the problems of established methods like dither lock or ramp and fire. Furthermore, our method opens the possibility to switch between two wavelengths for alternating shots, in contrast to most established techniques that only allow operation at one wavelength.", "author_names": [ "Klaus Ertel", "Holger Linne", "Jens Bosenberg" ], "corpus_id": 43504393, "doc_id": "43504393", "n_citations": 35, "n_key_citations": 0, "score": 0, "title": "Injection seeded pulsed Ti:sapphire laser with novel stabilization scheme and capability of dual wavelength operation.", "venue": "Applied optics", "year": 2005 }, { "abstract": "Due to circumstances beyond the presenter's control, and audio recording was not possible for this presentation.", "author_names": [ "Vasily V Spirin", "Jose Luis Bueno Escobedo", "Krassimir Panajotov", "Patrice Megret", "Dmitry A Korobko", "Igor Zolotovskii", "Andrei A Fotiadi" ], "corpus_id": 216382359, "doc_id": "216382359", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Active stabilization of the DFB laser injection locked to an external fiber optic ring resonator", "venue": "Photonics Europe", "year": 2020 }, { "abstract": "Based on an analysis of differences between the experimentally measured temperature dependence of the current voltage characteristic (I V curve) of a laser diode bar (LDB) with AlGaAs/GaAs heterostructure and the dependence obtained in accordance with the well known model of light emitting diodes, assumptions were made about the sources of these differences. The agreement between the experimental and modeled dependences is significantly improved by taking into consideration the change in the resistance of LDB layers caused by temperature change. It is shown that when the injection current is known, the measured voltage drop across the LDB can be used to estimate the temperature of the diode active region in order to implement thermal stabilization for solid state laser pumping systems based on high power laser diodes.", "author_names": [ "A N Aparnikov", "E V Buryi", "N E Orlov" ], "corpus_id": 213701016, "doc_id": "213701016", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Temperature Dependence Model of the Laser Diode Bar Current Voltage Characteristic", "venue": "Optoelectronics, Instrumentation and Data Processing", "year": 2019 }, { "abstract": "Self injection locking to an external fiber cavity is an efficient technique enabling drastic linewidth narrowing and self stabilization of semiconductor lasers. The main drawback of this technique is its high sensitivity to fluctuations of the configuration parameters and surroundings. In the proposed laser configuration, to the best our knowledge, for the first time the self injection locking mechanism is used in conjunction with a simple active optoelectronic feedback, ensuring stable mode hopping free laser operation in a single longitudinal mode. Locking to 4 m length fiber resonator causes a drastic narrowing of the DFB laser linewidth down to 2.8 kHz and a reduction of the laser phase noise by three orders of magnitude. We have explored key features of the laser dynamics with and without active feedback, revealing stability and tunability of the laser linewidth as an additional benefit of the proposed technique.", "author_names": [ "Vasily V Spirin", "Jose Luis Bueno Escobedo", "Dmitry A Korobko", "Patrice Megret", "Andrei A Fotiadi" ], "corpus_id": 211725725, "doc_id": "211725725", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Stabilizing DFB laser injection locked to an external fiber optic ring resonator.", "venue": "Optics express", "year": 2020 }, { "abstract": "Self injection locking to an external fiber cavity is an efficient technique enabling drastic linewidth narrowing and self stabilization of semiconductor lasers. The main drawback of this technique is its high sensitivity to fluctuations of the configuration parameters and surroundings. In the proposed laser configuration, to the best our knowledge, for the first time the self injection locking mechanism is used in conjunction with a simple active optoelectronic feedback, ensuring stable mode hopping free laser operation in a single longitudinal mode. Locking to 4 m length fiber resonator causes a drastic narrowing of the DFB laser linewidth down to 2.8 kHz and a reduction of the laser phase noise by three orders of magnitude. We have explored key features of the laser dynamics with and without active feedback, revealing stability and tunability of the laser linewidth as an additional benefit of the proposed technique. (c) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement", "author_names": [ "", "S V", "B L" ], "corpus_id": 212699905, "doc_id": "212699905", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Stabilizing DFB laser injection locked to an external fiber optic ring resonator", "venue": "", "year": 2020 }, { "abstract": "We have demonstrated wavelength stabilization in an 821 nm AlGaAs three section tunable distributed Bragg reflector (DBR) semiconductor laser diode (LD) that consists of active, phase controlled, and DBR regions. We injected two separate, complementary currents into the active and the phase controlled regions in the DBR LD to suppress wavelength shift. This modulation method was applied to the LD fundamental wave in a second harmonic generation (SHG) laser, and the oscillating wavelength was maintained within the phase matching acceptance range of the SHG device during modulation. A peak blue violet light power of 62 mW was obtained for the ideal modulation waveform.", "author_names": [ "Yasuo Kitaoka", "Ken'ichi Kasazumi", "Akihiro Morikawa", "T Yokoyama", "Tomoya Sugita", "Kiminori Mizuuchi", "K Yamamoto", "Toru Takayama", "S Takigawa", "Masaaki Yuri" ], "corpus_id": 45433406, "doc_id": "45433406", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Wavelength stabilization of a distributed Bragg reflector laser diode by use of complementary current injection.", "venue": "Optics letters", "year": 2003 }, { "abstract": "We report the active frequency stabilization of a diode pumped microchip Nd:YAG laser using a frequency modulation sideband locking technique. The novel aspect of this scheme is that the piezo mounted output coupler acts as both the frequency modulator and the frequency correcting element. When the laser is locked to a reference cavity of 300 MHz free spectral range and 5 MHz linewidth, the laser frequency stability is found to be 88 kHz relative to the cavity.", "author_names": [ "Feng Zhou", "Allister I Ferguson" ], "corpus_id": 33937059, "doc_id": "33937059", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Frequency stabilization of a diode laser pumped microchip Nd:YAG laser at 1.3 microm.", "venue": "Optics letters", "year": 1991 }, { "abstract": "We implemented an optical frequency standard based on noise immune cavity enhanced optical heterodyne molecular spectroscopy (NICE OHMS) at 1.39 mm. The emission frequency of an extended cavity diode laser was actively stabilized against the center of the 4(4,1) 4(4,0) transition of the H(2)(18)O n1+n3 band, under optical saturation conditions. The nonlinear regime of laser gas interaction was reached by using an optical cavity with a finesse of about 8700. By filling it with an 18O enriched water sample at a pressure of a few Pa, the Lamb dip could be observed with a full width at half maximum of about 2 MHz. Absolute frequency stabilization was obtained by locking the cavity resonance to the center of the sub Doppler signal, which was provided by the NICE OHMS technique under the dispersion regime of operation. An Allan deviation analysis demonstrated a relative frequency stability of ~5x10( 13) for an integration time of 1 s. For longer integration times, the flicker frequency noise floor set the stability at the level of 4x10( 14)", "author_names": [ "Hemanth Dinesan", "Eugenio Fasci", "Antonio Castrillo", "Livio Gianfrani" ], "corpus_id": 43709746, "doc_id": "43709746", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "Absolute frequency stabilization of an extended cavity diode laser by means of noise immune cavity enhanced optical heterodyne molecular spectroscopy.", "venue": "Optics letters", "year": 2014 }, { "abstract": "Self injection locking, an efficient method to improve the spectral performance of semiconductor lasers without active stabilization, has already demonstrated its high potential for operation with single longitude mode fiber lasers urgently demanded by new applications in optical metrology and spectroscopy, coherent optical communications, distributed fiber sensing. The laser operation stability remains to be a crucial issue for such laser applications. Here, we present a theoretical framework for modeling of semiconductor laser coupled to an external fiber optic ring resonator. The developed approach has shown good qualitative agreement with theoretical predictions and experimental results for particular configuration of a self injection locked DFB laser delivering narrow band radiation and particular employed in Brillouin fiber laser configurations. The model is capable of describing the main features of the experimentally measured laser outputs such as laser line narrowing, spectral shape of generated radiation, mode hoping instabilities and makes possible exploring the key physical mechanisms responsible for the laser operation stability.", "author_names": [ "Dmitry A Korobko", "Igor O Zolotovsky", "Krassimir Panajotov", "Vasily V Spirin", "Andrei A Fotiadi" ], "corpus_id": 139354741, "doc_id": "139354741", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Modeling of a semiconductor laser coupled to an external fiberoptic ring resonator", "venue": "Photonics Europe", "year": 2018 } ]

[ { "abstract": "The development of artificially structured electromagnetic materials, termed metamaterials, has led to the realization of phenomena that cannot be obtained with natural materials. This is especially important for the technologically relevant terahertz (1 THz 1012 Hz) frequency regime; many materials inherently do not respond to THz radiation, and the tools that are necessary to construct devices operating within this range sources, lenses, switches, modulators and detectors largely do not exist. Considerable efforts are underway to fill this 'THz gap' in view of the useful potential applications of THz radiation. Moderate progress has been made in THz generation and detection; THz quantum cascade lasers are a recent example. However, techniques to control and manipulate THz waves are lagging behind. Here we demonstrate an active metamaterial device capable of efficient real time control and manipulation of THz radiation. The device consists of an array of gold electric resonator elements (the metamaterial) fabricated on a semiconductor substrate. The metamaterial array and substrate together effectively form a Schottky diode, which enables modulation of THz transmission by 50 per cent, an order of magnitude improvement over existing devices.", "author_names": [ "Hou-Tong Chen", "Willie J Padilla", "Joshua M O Zide", "Arthur C Gossard", "Antoinette J Taylor", "Richard D Averitt" ], "corpus_id": 2515680, "doc_id": "2515680", "n_citations": 949, "n_key_citations": 16, "score": 1, "title": "Active terahertz metamaterial devices", "venue": "Nature", "year": 2006 }, { "abstract": "A wide variety of optical phenomena rely on the near field manipulation and confinement of electromagnetic field in subwavelength metallic and dielectric resonators with applications ranging from the design of micro and nano scale photonic devices to super lenses and ultrasensitive sensors. In this invited paper, we present a discussion on controlling the metamaterial properties by active and passive manipulation of near field coupling in an array of split ring resonators. We show that near field coupling between the meta atoms could lead to resonance tuning, mode splitting, and ultrafast switching in passive and active resonators. The near field coupling schemes discussed here demonstrate the application possibilities of such structures towards the design of active switches, amplitude modulators, frequency agile behaviors, and slow light devices, particularly for the terahertz frequency regime, which still suffers from the shortage of practical devices required to bridge the so called \"THz gap\"", "author_names": [ "Dibakar Roy Chowdhury", "Abul Kalam Azad", "Weili Zhang", "Ranjan Singh" ], "corpus_id": 10972371, "doc_id": "10972371", "n_citations": 30, "n_key_citations": 0, "score": 0, "title": "Near Field Coupling in Passive and Active Terahertz Metamaterial Devices", "venue": "IEEE Transactions on Terahertz Science and Technology", "year": 2013 }, { "abstract": "We demonstrate THz metamaterials exhibiting either amplitude control, via carrier injection or depletion in the active semiconductor substrate or frequency control, via photoexcitation of carriers into active semiconducting materials incorporated into the sub wavelength metamaterial structure.", "author_names": [ "Hou-Tong Chen", "John F O'Hara", "Abul Kalam Azad", "David Shrekenhamer", "Willie J Padilla", "Joshua M O Zide", "Arthur C Gossard", "Richard D Averitt", "Antoinette J Taylor" ], "corpus_id": 221004683, "doc_id": "221004683", "n_citations": 202, "n_key_citations": 1, "score": 0, "title": "Active Terahertz Metamaterial Devices", "venue": "", "year": 2008 }, { "abstract": "In the above named work [ibid, vol. 3, no. 6, pp. 783 790, Nov. 2013] the mention of a funding agency was inadvertently omitted in the Acknowledgment. The omitted text in the Acknowledgement section [1, p. 788] is provided here.", "author_names": [ "Dibakar Roy Chowdhury", "Abul Kalam Azad", "Wensheng Zhang", "Rajdeep Singh" ], "corpus_id": 122656090, "doc_id": "122656090", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Corrections to \"Near field coupling in passive and active teraHertz metamaterial devices\"", "venue": "", "year": 2014 }, { "abstract": "", "author_names": [ "Hou-Tong Chen" ], "corpus_id": 137285972, "doc_id": "137285972", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Active Terahertz metamaterial devices", "venue": "", "year": 2010 }, { "abstract": "", "author_names": [ "Xiaoguang Zhao" ], "corpus_id": 114326201, "doc_id": "114326201", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Active metamaterial devices at terahertz frequencies", "venue": "", "year": 2016 }, { "abstract": "Abstract Arbitrarily controlling the reflection/transmission/absorption state of electromagnetic waves, especially their dynamical manipulation, is on high demand due to the growing development of practical optical devices and application systems. In this work, we present a scheme to dynamically manipulating terahertz wave reflection/transmission/absorption using the active metamaterial composed of a layer of metallic structural and two graphene sandwich structures as well as polymer spacers. By adjusting the Fermi level of graphene, this tunable metamaterial can achieve electronically reconfigurable terahertz reflection, transmission and absorption in a highly efficient manner. Furthermore, it also enables continuous dynamical modulation between any two among the three states. The presented metamaterial is a promising candidate for exploring active terahertz devices for dynamically controlling the state of light matter interactions and have potential applications in optoelectronic devices, wireless communication and frequency selective surface.", "author_names": [ "Yin Sheng Zhang", "Yijun Feng", "Junming Zhao" ], "corpus_id": 225029615, "doc_id": "225029615", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Graphene enabled active metamaterial for dynamical manipulation of terahertz reflection/transmission/absorption", "venue": "", "year": 2020 }, { "abstract": "Within the last years there has been a tremendous thrust into research and technology in the THz spectral region (broadly defined as 0.1 10 THz) mainly driven by the unique potential where this radiation finds applications in, such as imaging, spectroscopy and communication. In all these fields a fast, integrated and versatile platform for modulating light is required. Metamaterial/graphene devices fulfill all these requirements as their subwavelength nature lends itself naturally to strong light matter interaction, and therefore highly efficient and miniaturized devices. Graphene's unique properties, e.g. the large carrier concentration modulation, provide a large degree of compatibility with several architectures which can be exploited in a range of modulation or detection schemes. Finally, metamaterial/graphene devices realize a fast, versatile platform, which can be easily scaled to other frequencies, and adapted into amplitude, frequency, polarization and phase modulators, as well as integrated detectors, for the next generation of wireless communication.", "author_names": [ "Riccardo Degl'Innocenti", "Stephen J Kindness", "Nikita W Almond", "Wladislaw Michailow", "Philipp Braeuninger-Weimer", "Stephan Hofmann", "Harvey E Beere", "David A Ritchie" ], "corpus_id": 201067775, "doc_id": "201067775", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Metamaterial/graphene active terahertz modulators", "venue": "2019 IEEE MTT S International Wireless Symposium (IWS)", "year": 2019 }, { "abstract": "of \"Active Metamaterial and Waveguide Devices with Applications in Terahertz Communications\" by Nicholas J. Karl, Ph.D. Brown University, May 2018 This work was motivated by the need to demonstrate new capabilities in the terahertz frequency range for modulation, multiplexing and beam steering. Which is driven by the demand for wireless communication networks to operate at terahertz frequencies within the coming decade. A promising candidate to address these challenges is the active terahertz metasurface. This photonic component is based on a metamaterial that is tunable through the application of an external voltage bias. The metasurface is an array of metamaterial elements in a two dimensional grid, patterned on a semiconductor substrate. I present analytic and experimental evidence that these metasurface devices have good performance characteristics as diffractive modulators, which can reach up to 20 dB modulation depth at kilohertz switching speeds. I illustrate that the diffracted radiation has larger bandwidth than the amplitude resonance data predicts, which indicates that a combined amplitude phase modulation leads to broadband operation. To understand this behavior I characterize the metasurface using terahertz ellipsometry. The characterization of the active response of an electrically tunable metamaterial is an open problem worth studying. Having a good understanding of this behavior will help guide active metamaterial device design. I present experimental data and an ellipsometric model involving finiteelement method simulations. I find a relation between the voltage applied to the metamaterial and the epilayer conductivity, a useful result that can be used in device design. Finally I use this result to design a phase modulator device. In addition to metamaterials, I study a parallel plate waveguide based leaky wave antenna, which demonstrates multiplexing capability in the terahertz frequency range. Taking advantage of a phase matching condition in the dispersive TE1 waveguide mode, the leaky wave antenna can multiplex frequencies together, and demultiplex a broadband beam. I provide experimental and numerical evidence showing how the device functions, and demonstrate multiplexing and demultiplexing behavior. I show how this device has a large parameter space, describe a possible design scenario, and develop a strategy for multiplexing 6 channels of 20 GHz bandwidth each. Devices that exhibit these kinds of functionality will play a large role in the architecture of future terahertz wireless networks. Active Metamaterial and Waveguide Devices with Applications in Terahertz Communications By Nicholas Jason Karl A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the School of Engineering at Brown University Providence, Rhode Island May 2018 (c) 2018 by Nicholas J. Karl", "author_names": [ "Nicholas Karl" ], "corpus_id": 139579033, "doc_id": "139579033", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Active Metamaterial and Waveguide Devices with Applications in Terahertz Communications", "venue": "", "year": 2018 }, { "abstract": "Active control of terahertz waves is critical to the development of terahertz devices. Two dimensional materials with excellent optical properties provide more choices for opto electrical devices due to the advancement in their preparation technology. We proposed a hybrid structure of a metamaterial/monolayer MoS2/Si and investigated its optical properties in the terahertz range. The plasmon induced transparency (PIT) effect was observed in the transmission spectra, resulting from the near field coupling of two bright modes. According to the simulated results, this phenomenon confirmed its dependency on the length of the cutwire and the distance between DSSRs. Furthermore, an external optical field supported by a 1064 nm laser could exert a switch effect on the sample. The resonances of the PIT metamaterial disappeared when the optical power was further increased, as the excited carriers in the MoS2/Si substrate blocked the coupling effect. In addition, the experimental results indicated that the PIT metamaterial enhanced the interaction of infrared light with the monolayer MoS2/Si substrate.", "author_names": [ "Jie Ji", "Siyan Zhou", "Weijun Wang", "Furi Ling", "Jianquan Yao" ], "corpus_id": 140266815, "doc_id": "140266815", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Active control of terahertz plasmon induced transparency in the hybrid metamaterial/monolayer MoS2/Si structure.", "venue": "Nanoscale", "year": 2019 } ]

[ { "abstract": "We experimentally explore and demonstrate the potential of a birefringent fiber loop (BFL) to compensate for the pattern effects (PE) induced in a reflective semiconductor optical amplifier (RSOA) which is driven by optical data whose intensity, temporal and spectral characteristics heavily stress the RSOA. By properly tailoring the BFL comb like profile and adjusting the relative offset between the BFL maximum transmission and carrier signal position, the BFL improves the RSOA pattern dependent performance even though the input pulses' modulation bandwidth exceeds the 3 dB cut off frequency of the RSOA optical response. The extensive set of obtained experimental results confirms the BFL capability to enhance the RSOA operation even under strong saturation, since the BFL acts in a beneficial manner on the amplified pulses by reducing their overshoot to an acceptable level, restoring their spectral position, reshaping their eye diagram and increasing their input power dynamic range. These notable improvements, combined with the construction from off the shelf components, straightforward implementation, simplicity of operation and flexibly tunable transmission characteristics, render the BFL an attractive solution for efficiently combating the RSOA PE and resolving its undesirable complications.", "author_names": [ "Kyriakos E Zoiros", "Dimitrios Kastritsis", "Thierry Rampone", "Ammar Sharaiha" ], "corpus_id": 225511819, "doc_id": "225511819", "n_citations": 2, "n_key_citations": 1, "score": 1, "title": "Reflective semiconductor optical amplifier pattern effect compensation with birefringent fiber loop", "venue": "", "year": 2020 }, { "abstract": "All optical two's complement generator for four bit binary numbers and single bit comparator is proposed and analysed using reflective semiconductor optical amplifier (RSOA) We use Soliton bits to implement the device and therefore, find application in long distance communication systems. The performance is analysed in terms of input output bit patterns, quality factor, pseudo eye diagram, relative eye opening and amplified spontaneous emission characteristics.", "author_names": [ "K Mukherjee", "Kajal Maji", "Ashif Raja" ], "corpus_id": 219500224, "doc_id": "219500224", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "All optical four bit two's complement generator and single bit comparator using reflective semiconductor optical amplifier", "venue": "", "year": 2020 }, { "abstract": "Reflective semiconductor optical amplifiers (RSOAs) are versatile gain media that find applications in passive optical networks. Due to their double pass characteristics, they show better gain compared with ordinary semiconductor optical amplifiers, resulting in better switching performance. In this work, the RSOA based gain dynamics is utilized to design and analyze a parity checker and generator using soliton pulses. The results of MATLAB simulations at a rate of 200 Gbps show the practical feasibility of such gates. The effect of the amplified spontaneous emission noise on the performance of the logic gate is also investigated.", "author_names": [ "Kajal Maji", "K Mukherjee", "Ashif Raja", "Jitendra Nath Roy" ], "corpus_id": 213220487, "doc_id": "213220487", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Numerical simulations of an all optical parity generator and checker utilizing a reflective semiconductor optical amplifier at 200 Gbps", "venue": "", "year": 2020 }, { "abstract": "In this chapter, we have analyzed and described all optical soliton based logic AND gate using refractive semiconductor optical amplifier (RSOA) We have used control signal and data signal as a soliton pulse. Input and output operations are also shown. We have found output extinction ratio, contrast ratio, relative eye opening, and quality factor and how they vary with control pulse energy for the optimization of the performance.", "author_names": [ "Kajal Maji", "K Mukherjee", "A Raja" ], "corpus_id": 213608540, "doc_id": "213608540", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Performance of All Optical Logic Soliton Based AND Gate Using Reflective Semiconductor Optical Amplifier (RSOA)", "venue": "", "year": 2019 }, { "abstract": "A new time domain wideband numerical model for simulation of quantum dot reflective semiconductor optical amplifier (QD RSOA) steady state and dynamic behavior, is described. The model is used to investigate 1 ps full width at half maximum input Gaussian pulse amplification and also modulation cancellation. A large modulation cancellation dynamic range of about 35 dB, is predicted for high input powers, which is not attainable in bulk and QW RSOAs. The model can be applied to traveling wave and reflective QD SOAs. The combination of the unique features of quantum dots and a reflective structure can be used to realize a colorless modulator for wavelength division multiplexed passive optical networks (WDM PONs)", "author_names": [ "Khalil Safari Anzabi", "Amir Habibzadeh-Sharif", "Michael J Connelly", "Ali Rostami" ], "corpus_id": 209985489, "doc_id": "209985489", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Wideband Steady State and Pulse Propagation Modeling of a Reflective Quantum Dot Semiconductor Optical Amplifier", "venue": "Journal of Lightwave Technology", "year": 2020 }, { "abstract": "The feasibility of employing a birefringent fiber loop to enhance the performance of a directly modulated reflective semiconductor optical amplifier is experimentally demonstrated for the first time. The birefringent fiber loop acts as an optical filter of opposite slope than that of the reflective semiconductor optical amplifier electro optical response and counteracts the finite reflective semiconductor optical amplifier modulation bandwidth of only 0.89 GHz. By proper adjustment of its detuning, the birefringent fiber loop tailors the spectral components that physically manifest due to the reflective semiconductor optical amplifier dynamic perturbation subject to direct modulation in the saturated gain regime, and suppresses the pattern dependent distortions in the time domain. In this manner, the birefringent fiber loop manages to significantly improve the quality characteristics of the encoded signal at higher data rates than those enabled by the reflective semiconductor optical amplifier limited modulation capability. Owing to the birefringent fiber loop, the reflective semiconductor optical amplifier modulation range is extended to 4 Gb/s at the raw bit error rate of 1.0x10 9, and to 11 Gb/s at the forward error correction limit of 3.8x10 3. These results, which are unique against the evaluation criterion adopted in the first case, and the modulation speed achieved with post filtering schemes in the second, highlight the beneficial role that the birefringent fiber loop can play in supporting reflective semiconductor optical amplifier operation for intensity amplification and modulation purposes.", "author_names": [ "Zoe V Rizou", "Kyriakos E Zoiros", "Thierry Rampone", "Ammar Sharaiha" ], "corpus_id": 225520468, "doc_id": "225520468", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Reflective Semiconductor Optical Amplifier Direct Modulation Capability Enhancement Using Birefringent Fiber Loop", "venue": "", "year": 2020 }, { "abstract": "All Optical Two's complement generator for four bit binary numbers is proposed and analyzed using reflective semiconductor optical amplifier (RSOA) We use Soliton bits to implement the device and therefore, find application in long distance communication systems. The performance is analyzed in terms of input output bit patterns, quality factor, pseudo eye diagram, relative eye opening and amplified spontaneous emission.", "author_names": [ "K Mukherjee", "Kajal Maji", "Ashif Raja" ], "corpus_id": 199441353, "doc_id": "199441353", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Design and performance analysis of all optical Soliton based 4 bit two's complement generator using Reflective Semiconductor Optical Amplifier", "venue": "2019 Devices for Integrated Circuit (DevIC)", "year": 2019 }, { "abstract": "A dilute waveguide reflective semiconductor optical amplifier for alignment tolerant hybrid silicon photonics integration was demonstrated with emitting wavelength of $1.55\\ \\mu \\mathrm{m} Far field divergence angle at fast diverge axis was 11.8deg compares to conventional waveguide of 28.2deg. The dilute waveguide demonstrated 45% alignment tolerance improvement with mode size of $84\\ \\mu \\mathrm{m}{2}", "author_names": [ "Bowen Song", "Youning Luo", "Sergio Pinna", "Yuan Liu", "Jonathan Klamkin" ], "corpus_id": 201812296, "doc_id": "201812296", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Dilute Waveguide Reflective Semiconductor Optical Amplifier for 3D Hybrid Silicon Photonics Integration", "venue": "2019 Compound Semiconductor Week (CSW)", "year": 2019 }, { "abstract": "We demonstrate the feasibility of using a single microring resonator (MRR) as optical notch filter for enabling the direct modulation of a reflective semiconductor optical amplifier (RSOA) at more than tripled data rate than possible with the RSOA alone. We conduct a thorough simulation analysis to investigate and assess the impact of critical operating parameters on defined performance metrics, and we specify how the former must be selected so that the latter can become acceptable. By using an MRR of appropriate radius and detuning, the RSOA modulation bandwidth, which we explicitly quantify, can be extended to overcome the RSOA pattern dependent performance limitations. Thus, the MRR makes the RSOA encoded signal exhibit improved characteristics that can be exploited in practical RSOA direct modulation applications.", "author_names": [ "Zoe V Rizou", "Kyriakos E Zoiros" ], "corpus_id": 3330020, "doc_id": "3330020", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Theoretical Analysis of Directly Modulated Reflective Semiconductor Optical Amplifier Performance Enhancement by Microring Resonator Based Notch Filtering", "venue": "", "year": 2018 }, { "abstract": "", "author_names": [ "Kajal Maji", "K Mukherjee", "Mrinal Kanti Mandal" ], "corpus_id": 229413515, "doc_id": "229413515", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Simulative Performance Analysis of All Optical Universal Logic TAND Gate Using Reflective Semiconductor Optical Amplifier (RSOA)", "venue": "", "year": 2020 } ]

[ { "abstract": "Abstract CdS, as semiconductor catalyst, has attracted much attention in photocatalytic production of hydrogen for the wide range utilization of visible light. Usually, noble metal deposited as a co catalyst on CdS surface is required to achieve high photocatalytic activity. Thus, replacing noble metal via cheap and easy synthesis co catalyst would be of great value for developing cost effective photocatalyst. In this work, noble metal free defective Mo15S19 combined with CdS diethylenetriamine (DETA) hybrid makes efficient separation of photoinduced carriers, and more importantly, reduced overpotential for hydrogen evolution reaction, thereby improved catalytic hydrogen evolution performance of designed composite. In particular, 3%Mo15S19/CdS DETA systems exhibited a high rate of hydrogen production, reaching 3.61 mmol g 1 h 1, which is similar with 3%Pt/CdS DETA and 9.5 and 2.19 times as high as that of CdS nanoparticles (NPs) and CdS DETA, respectively. At the same time, photocorrosion resistance of 3%Mo15S19/CdS DETA systems was dramatically improved. According to DFT theoretical calculations, it was found that the enhanced photocatalytic performance and anticorrosion are mainly due to efficient transfer of photoexcited electrons from CdS DETA to Mo15S19.", "author_names": [ "Zhen Li", "Yang Yang", "Kai Dai", "Jinfeng Zhang", "Luhua Lu" ], "corpus_id": 105835770, "doc_id": "105835770", "n_citations": 31, "n_key_citations": 0, "score": 0, "title": "Construction of defective Mo15S19/CdS diethylenetriamine heterosctructure photocatalyst for highly active and stable noble metal free photocatalytic hydrogen production", "venue": "Applied Surface Science", "year": 2019 }, { "abstract": "Construction industry is of critical significance to the development of Australia regarding economic and social aspect, contributing one of the largest portions to Australia's GDP and providing residential building, infrastructure and functional facilities to the operation of the cities as well as job opportunities to the country. Construction disputes are common trait of this industry causing detrimental consequences to the construction projects leading to financial loss and delays in construction projects. Although there is a considerable amount of research and knowledge contributing to the study of dispute causation, legal disputes remain prevailing and hinder the process of construction, especially from the cost perspective. In order to improve our understanding of the causation factors underlying the legal disputes this research was conducted by examining the details of recent legal cases in NSW. Our objective was to determine the extent of the impact of insufficient work front instruction including missing specifications on occurrence of defective construction work. As a result, this research discusses that poor workmanship as a major causation factor is a direct derivative of vague job description. The observation that patent defects readily identifiable by inspection were a common source of dispute supports our hypothesis that ambiguity of the task provides tradespersons the opportunity to deliver a sub standard job. Professional ethics and technical skills of the tradies have been discussed to have a moderating effect. Clear and precise specifications are inevitable if disputes are to be reduced.", "author_names": [ "Zhaorong Wu", "Payam Rahnamayie Zekavat", "Sungkon Moon", "Liyaning Tang", "Sherif Mostafa" ], "corpus_id": 213302910, "doc_id": "213302910", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Investigating the root cause of legal disputes over defective construction", "venue": "", "year": 2019 }, { "abstract": "Purpose: Poor project knowledge and inadequate experience are frequently linked to construction time cost overruns. This paper aims to expound on the criticality of project knowledge and experience in the successful delivery of projects in the construction industry. Design/methodology/approach: Following a detailed literature review, a quantitative positivist approach with a questionnaire survey involving industry professionals is used to appraise the 30 prevalent causes of time cost overruns according to frequency, effectiveness and importance indices. The data are then subjected to Spearman's rank correlation tests and exploratory factor analysis. Findings: Using the importance index, which assimilates both frequency and effectiveness indices, the criticality of knowledge and experience in the overall context is seen as fundamental for addressing the contractor's faulty planning and scheduling, construction mistakes and defective work, site management and supervision, delayed/slow decision making, incomplete drawings and design documents and change/variation orders. Spearman's rank correlation tests indicate a good consensus of perceptions among the key parties involved. Next, an exploratory factor analysis uncovers six underlying knowledge based factors affecting construction performance, relating to inaccurate resource estimates, design changes, resource shortages, lack of experience, incompetence and mistakes and defects. Originality/value: The study draws out the repercussions of the hitherto limited research into the deficiencies in knowledge and experience in undertaking construction projects to enhance performance using knowledge management functions.", "author_names": [ "Jeffrey B H Yap", "Ban Leong Lim", "Martin Skitmore", "Jason Gray" ], "corpus_id": 234054526, "doc_id": "234054526", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Criticality of project knowledge and experience in the delivery of construction projects", "venue": "", "year": 2021 }, { "abstract": "Abstract Since the end of the twentieth century, discussion on dwelling rehabilitation versus its demolition and new construction has been steadily increasing in intensity, which is especially due to the necessity for the regeneration of urban centres. However, rehabilitation is not always considered the most economical solution, and demolition and new construction may constitute a better option. In the present work, a multi family building in Seville, Spain, is used as a case study. After having suffered damage from a construction failure, it is assessed for its complete rehabilitation. Defective maintenance has worsened the bad condition of the building. A model is proposed, from the project budget perspective, that allows the environmental (Ecological Footprint indicator) and the economic (project's bill of quantities) assessment of the recovery of the dwelling. In the case study, the rehabilitation Ecological Footprint and the project cost are 0.06 gha/m 2 of floor area (457.22 EUR/m 2 and 0.14 gha/m 2 (576.33 EUR/m 2 for a new building on the same plot, respectively. It can be deduced that, even with a severely damaged building, the repair and retrofit work incurs a lower economic and environmental impact than that of the total replacement with a new construction.", "author_names": [ "Ma Desiree Alba-Rodriguez", "A Martinez-Rocamora", "Patricia Gonzalez-Vallejo", "Antonio Ferreira-Sanchez", "Madelyn Marrero" ], "corpus_id": 134613751, "doc_id": "134613751", "n_citations": 50, "n_key_citations": 0, "score": 0, "title": "Building rehabilitation versus demolition and new construction: Economic and environmental assessment", "venue": "", "year": 2017 }, { "abstract": "In this short paper, we compare well known rule/tree classifiers in software defect prediction with the CTC decision tree classifier designed to deal with class imbalanced. It is well known that most software defect prediction datasets are highly imbalance (non defective instances outnumber defective ones) In this work, we focused only on tree/rule classifiers as these are capable of explaining the decision, i.e. describing the metrics and thresholds that make a module error prone. Furthermore, rules/decision trees provide the advantage that they are easily understood and applied by project managers and quality assurance personnel. The CTC algorithm was designed to cope with class imbalance and noisy datasets instead of using preprocessing techniques (oversampling or undersampling) ensembles or cost weights of misclassification. The experimental work was carried out using the NASA datasets and results showed that induced CTC decision trees performed better or similar to the rest of the rule/tree classifiers.", "author_names": [ "Igor Ibarguren", "Jesus M Perez", "Javier Muguerza", "Daniel Rodriguez", "Rachel Harrison" ], "corpus_id": 4114035, "doc_id": "4114035", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "The Consolidated Tree Construction algorithm in imbalanced defect prediction datasets", "venue": "2017 IEEE Congress on Evolutionary Computation (CEC)", "year": 2017 }, { "abstract": "The residential construction industry is an important contributor to the Australian economy; the industry employs a very large component of the national workforce, and yet the industry is plagued by defective work and poor quality. Previous research has revealed that defects and rework are endemic in the residential sector. In an attempt to quantify the degree of defects being experienced in new residential construction this paper provides an analysis of defects that were recorded by a government owned housing insurance organization, the Housing Guarantee Fund. This research represents one of the most comprehensive research studies of building defects undertaken to date in Australia. The data used were not based on a sample like previous studies but instead represent all new houses constructed in Victoria, Australia between 1982 and 1997. An analysis of the data revealed that one house in eight reported defects, and that the cost of rectification was 4% of the construction contract value. The paper discusses the nature of the most important defects and investigates the impact of contractor type and building type.", "author_names": [ "Anthony Mills", "Peter E D Love", "Patricia J Williams" ], "corpus_id": 109642072, "doc_id": "109642072", "n_citations": 141, "n_key_citations": 15, "score": 1, "title": "Defect Costs in Residential Construction", "venue": "", "year": 2009 }, { "abstract": "Concrete is most utilized construction materials, it is having many advantages, some are low cost, long service life (when properly mixed, placed and cured) ease of construction and high compressive strength. In present time the civilization depends upon the available ranges of concrete or reinforced concrete (RC) structures, ranging from domestic structures to heavy structures. However, numerous concrete structures suffer important degradations and damages due to environmental exposure or extraordinary overload or have insufficient strength because of defective construction, increased service load requirements, or updated codes, fiber reinforced polymer (FRP) composites strengthening becoming nowadays a commonly accepted and widespread technique. The research includes static analysis of beam under glass fiber composite plate with PCC and RCC to optimize material and cost of beam with designed strength. In present research work the response of plain concrete beam, reinforced concrete beam and reinforced concrete beam with GFRP plate is analysed with finite element analysis sotware. ABAQUS software is used to perform analysis of beam. The results and outcomes of analysis concluded that the reinforced concrete beam with GFRP plate gives better results than any other case taken under consideration.", "author_names": [ "P K Joshi", "Komal Bedi" ], "corpus_id": 213274397, "doc_id": "213274397", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Static Finite Element Analysis of Gfrc Simply Supported Beam", "venue": "", "year": 2019 }, { "abstract": "The techniques of strengthening reinforced concrete beams have been widely used in civil engineering. RC beams often need strengthening due to defective construction, having higher loads than those foreseen in the initial design of the structure, or as a result of material deterioration or accidental damage. The need for strengthening concrete structures has become a crucial problem all over the world. Rehabilitation of structures results in less construction waste materials, reserve natural resources, reduces the negative effects of the environment, saves time and cost, etc. The structural behavior of reinforced concrete beams strengthened by addition of steel plates or steel angles has been investigated in the undertaken research. The main aim of this research is to demonstrate the best method of the investigated strengthening techniques. The experimental work comprised of 18 RC beams divided into three groups; the first group consists of 6 normal RC beams, the second group contains 6 RC beams strengthened by addition of steel plates and the third group contains 6 RC beams strengthened by addition of steel angles. Keywords: Steel Plate, Steel Angle, RC Beam, Concrete", "author_names": [ "Ali I Tayeh", "Sari W Abusharar" ], "corpus_id": 55904049, "doc_id": "55904049", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Comparative Study on the Strengthening of RC Beams with Steel Plates and Steel Angles", "venue": "", "year": 2018 }, { "abstract": "In the last decades, developing and sustaining large complex engineering systems have become more challenging (de Graaf, Voordijk, van den Heuvel, 2016) To facilitate contracting firms in the Dutch construction industry in their ability to deliver these more complex projects, innovative procurement methods based on integrated contracts, using Uniform Administrative Conditions for Integrated Contracts (UAV ic) such as Design Build or Design Build Maintain, are used by large clients in the Dutch construction Industry (de Graaf, Vormer, Boes, 2017; Makkinga, de Graaf, Voordijk, 2018) The transfer of responsibility from clients to contracting firms for the project design creates the demand for contracting firms to control and review the quality of their own work. Design decisions and commitments have a great impact on project life cycle cost and defective design is a major cause of contract claims and change orders during construction (Andi Minato, 2003) de Graaf et al. (2016) and de Graaf, Vormer, et al. (2017) argue for a transition to the SE way of working in the Dutch construction industry. Reef Infra, a mid sized Dutch contracting firm, finds it challenging to increase standardization, independency, and overall performance regarding their SE process and finds it also challenging to collect performance information to SE related tasks. SE is a relative new way of working, which leads to a lot of insecurity (within the organization) struggle and discussion between Reef Infra and their clients and between Reef Infra and their subcontractors. Reef Infra is looking for opportunities to measure their SE performance to find or identify opportunities for improvement. Measuring their SE performance enables them to target underperforming SE tasks. Alongside their wish to improve their SE application, Reef Infra also finds it challenging to collect performance information, specifically regarding SE tasks and how to relate this to common project success categories in terms of budget, schedule and quality. When they are able to quantify this relation, Reef Infra can prove that their control over the SE process contributes to common project success categories and that they can use that information for BVP tenders. To identify solutions for these challenges a research project is conducted. The project is performed to answer the following research question: How can a Civil Engineering Contracting Firm measure their Systems Engineering performance and how do these metrics relate to project success indicators budget, schedule and quality? In this research project, a measurement tool is developed and applied to measure SE performance and project success in terms of budget, schedule and quality. The goal of the research is to assist Reef Infra in their improvement of their SE process by measuring their SE application in projects under UAC ic. In addition, how SE contributes to achieving project success indicators budget, schedule and quality, which are commonly used as BVP objectives, is also explored. The goal within the research is to advice Reef Infra how they can measure their SE application to improve their SE process and to relate the extent of SE application to project success indicators budget, schedule and quality. A case study research design is applied to develop and apply the measurement tool. Multiple cases were selected according to the one phase screening approach of Yin (2014) There were two main sources of evidence to fill the measurement tool. First, an extensive document analysis was performed to provide initial results. Afterwards, unstructured interviews were conducted to fill gaps in the results and validate findings. A case study protocol was developed to ensure that within case results are mutually comparable in the cross case analysis. Based on the results of the research, the relation between the extent of SE application and project success cannot be determined. Too little data points were gathered. Looking at the graphs (Figure 8, Figure 9 and Figure 10) there is no optimum in the extent of SE application in relation to project performance. It is unclear if a higher or lower extent of SE application could prevent such events from happening. The findings of Honour (2013) and Beasley and O'Neil (2016) cannot be confirmed, because no clear relation cannot be established. Moreover, in the cases many other characteristics or events seem to affect the project success. To eliminate bias of such characteristics on the relation between the extent of SE application and project success, more assessments of projects using the measurement tool have to be conducted. The results do however confirm that the extent of SE application is different in each project. Although, all projects score an average SE score within a range of approximately 10% because the maximum score was 66% and the lowest score was 56% The results suggest that SE elements are in some projects not applied while in other projects the same SE elements were applied quite substantially. This means Reef Infra does not apply a comprehensive and standardized SE method in their civil engineering projects. There are multiple reasons for the extent of SE application. First, unclear and out of date SE procedures affect the extent of SE application. Second, the level of SE skill and knowledge affected the extent of SE application. Third, Reef Infra is highly dependent on the client for the extent of SE application. Establishing clear SE procedures, enhancing SE skill and knowledge and reducing client dependency could enable the contractor to properly assess the extent of SE necessary to realize project success. A contingency approach to SE in construction projects can prevent over and underinvestment. Relating SE performance to project success, enables proper recognition of how much SE activity is enough. This aspect must be further explored to establish clear methods for recognition. The approach to SE must be corresponding with the characteristics of the project, otherwise SE does not provide value in the project. Although, the measurement tool developed in the research emphasizes the extent of SE process applied at the project level it does provide the contracting firm with the necessary information to target underperforming SE tasks. Overall, to ensure that the contractor is capable of approach SE as a flexible process and not to overemphasize on SE tools, it is important the contractor must establish clear SE procedures, enhance SE skill and knowledge and reduce client dependency. To conclude, based on the qualitative case study research findings, the SE process framework is applicable to assess the extent of SE application at a civil engineering contracting firm. The output of the measurement tool provide contractors with vital information to improve their SE process. Moreover, three specific factors affecting the extent of SE application are derived from the results. Based on the results no clear relation could be established between the extent of SE application and project success in terms of budget, schedule and quality. However, the findings do suggest when more projects are assessed using the measurement tool a relation can be established and the bias effect of other characteristics and events that also affect project success can be eliminated. Therefore, Reef Infra benefits from further applying the measurement tool to assess the extent of SE application in their projects.", "author_names": [ "Ebel Berghuis" ], "corpus_id": 169074948, "doc_id": "169074948", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Measuring systems engineering and project success an evaluation of systems engineering practices and project duccess in a Dutch civil engineering contracting firm", "venue": "", "year": 2018 }, { "abstract": "In promoting the new rural cooperative medical system in our country,we face a series of problems such as,low participation; defective management system; high cost in collecting fund,unreasonable compensation standard,limited compensation ability; difficulty in supervision; defects in legislation and policy; lack of reasonable human resource system,and so forth. For the future,we need to normalize and improve it from the following aspects:strengthening the construction of managerial institutions and improving the management abilities; expanding channels for collecting fund,establishing long term effectiveness mechanism; improving the relation with the outside and forming positive interaction; establishing the rural urban integrated medical security system and management system as soon as possible; enhancing the medical supervision and improving the management efficiency; accelerating the work of legislation,ensuring the stability of policies on the new rural medical security system; reinforcing the human resource construction,emphasizing the cultivation of professionals for hospitals in townships,etc.", "author_names": [ "Chen Liu-qin" ], "corpus_id": 156230831, "doc_id": "156230831", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The New Rural Cooperative Medical System of Our Country:Characteristics,Problems and Countermeasures", "venue": "", "year": 2009 } ]

[ { "abstract": "Over the past years, to achieve better sensing performance, hafnium dioxide (HfO2) has been studied as an ion sensitive layer. In this work, thin layers of hafnium dioxide (HfO2) were used as pH sensitive membranes and were deposited by atomic layer deposition (ALD) process onto an electrolytic insulating semiconductor structure Al/Si/SiO2/HfO2 for the realization of a pH sensor. The thicknesses of the layer of the HfO2 studied in this work was 15, 19.5 and 39.9 nm. HfO2 thickness was controlled by ALD during the fabrication process. The sensitivity toward H+ was clearly higher when compared to other interfering ions such as potassium K+ lithium Li+ and sodium Na+ ions. Mott Schottky and electrochemical impedance spectroscopy (EIS) analyses were used to characterise and to investigate the pH sensitivity. This was recorded by Mott Schottky at 54.5, 51.1 and 49.2 mV/pH and by EIS at 5.86 p[H 1] 10.63 p[H 1] 12.72 p[H 1] for 15, 19.5 and 30 nm thickness of HfO2 ions sensitive layer, respectively. The developed pH sensor was highly sensitive and selective for H+ ions for the three thicknesses, 15, 19.5 and 39.9 nm, of HfO2 sensitive layer when compared to the other previously mentioned interferences. However, the pH sensor performances were better with 15 nm HfO2 thickness for the Mott Schottky technique, whilst for EIS analyses, the pH sensors were more sensitive at 39.9 nm HfO2 thickness.", "author_names": [ "Zina Fredj", "Abdoullatif Baraket", "Mounir Ben Ali", "Nadia Zine", "M Zabala", "Joan R Bausells", "Abdelhamid Elaissari", "Nsikak U Benson", "Nicole Jaffrezic-Renault", "Abdelhamid Errachid" ], "corpus_id": 234250127, "doc_id": "234250127", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Capacitance Electrochemical pH Sensor Based on Different Hafnium Dioxide (HfO2) Thicknesses", "venue": "", "year": 2021 }, { "abstract": "A simple optical pH sensor based on immobilization, Dioscorea alata L. anthocyanin methanol extract, onto a pectin chitosan polyelectrolyte complex (pectin chitosan PEC) has been successfully fabricated. The optical pH sensor was manufactured as a membrane made of pectin chitosan PEC and the extracted anthocyanin. This sensor has the highest sensitivity of anthocyanin content at 0.025 mg/L in phosphate buffer and 0.0375 mg/L in citrate buffer. It also has good reproducibility with a relative standard deviation %RSD) of 7.7% and gives a stable response at time values greater than 5 min from exposure in a buffer solution, and the sensor can be utilized within five days from its synthesis. This optical pH sensor has been employed to determine saliva pH of people of different ages and showed no significant difference when compared to a potentiometric method.", "author_names": [ "Eka Safitri", "Hani Humaira", "Murniana Murniana", "Nazaruddin Nazaruddin", "Muhammad Iqhrammullah", "Nor Diyana Md Sani", "Chakavak Esmaeili", "Susilawati Susilawati", "Muhammad Mahathir", "Salsabilla Latansa Nazaruddin" ], "corpus_id": 233397161, "doc_id": "233397161", "n_citations": 3, "n_key_citations": 1, "score": 0, "title": "Optical pH Sensor Based on Immobilization Anthocyanin from Dioscorea alata L. onto Polyelectrolyte Complex Pectin Chitosan Membrane for a Determination Method of Salivary pH", "venue": "Polymers", "year": 2021 }, { "abstract": "The sensitivity of conventional ion sensitive field effect transistors is limited to the Nernst limit (59.14 mV/pH) In this study, we developed a pH sensor platform based on a coplanar gate AlGaN/GaN metal oxide semiconductor (MOS) high electron mobility transistor (HEMT) using the resistive coupling effect to overcome the Nernst limit. For resistive coupling, a coplanar gate comprising a control gate (CG) and a sensing gate (SG) was designed. We investigated the amplification of the pH sensitivity with the change in the magnitude of a resistance connected in series to each CG and SG via Silvaco TCAD simulations. In addition, a disposable extended gate was applied as a cost effective sensor platform that helped prevent damages due to direct exposure of the AlGaN/GaN MOS HEMT to chemical solutions. The pH sensor based on the coplanar gate AlGaN/GaN MOS HEMT exhibited a pH sensitivity considerably higher than the Nernst limit, dependent on the ratio of the series resistance connected to the CG and SG, as well as excellent reliability and stability with non ideal behavior. The pH sensor developed in this study is expected to be readily integrated with wide transmission bandwidth, high temperature, and high power electronics as a highly sensitive biosensor platform.", "author_names": [ "Seong-Kun Cho", "Won-Ju Cho" ], "corpus_id": 233964338, "doc_id": "233964338", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "High Sensitivity pH Sensor Based on Coplanar Gate AlGaN/GaN Metal Oxide Semiconductor High Electron Mobility Transistor", "venue": "", "year": 2021 }, { "abstract": "Development of a new pH sensor system, which is simple to prepare, sensitive, selective and workable with low volume, is demanding research in biomedical and environmental studies. In the literature, organic molecules like methylene blue, toluidine blue, hydroquinone, catechol, anthraquinone and polyaniline based redox probes have been widely used for this purpose. In general, these redox probes have easily interfered with common biochemicals such as dopamine, ascorbic acid, NADH, H2O2, cysteine, hydrazine, and some transition metal ions, etc. and in turn to marked potential and current drifts (pH false positive response) In this work, a highly redox active, stable and interference free redox polymer based on poly(4 chloroaniline) (PANI(4 Cl) modified graphitized mesoporous carbon (GMC) designated as GMC@PANI(4 Cl) has been prepared using 4 chloroaniline as a monomer in pH 7 phosphate buffer solution. The new redox polymer system showed a distinct redox peak at Eo' 0.15 V vs Ag/AgCl with a stable voltammetric response. Transmission electron microscope analysis of the redox polymer composite had shown adhesion of black polymeric solid due to polyaniline like the molecular system as a surface layer on the GMC material. The constructed calibration plot was linear in the pH window 2 11 with a slope and regression values 58 mV pH 1 and 0.9997, respectively. The GMC@PANI(4 Cl) modified electrode showed a sensitive and selective pH monitoring without any interference from the common biochemicals as listed above. As a practical application, pH sensing of commercial pH solutions, undiluted urine and saliva samples were demonstrated. Also, a three in one screen printed carbon modified GMC@PANI(4 Cl) was explored for pH monitoring of a bacterial (E.coli) growth, which showed a comparable response with the conventional pH electrode. A poly(4 chloroaniline) modified graphitized mesoporous carbon electrode has been prepared for an efficient redox active system for voltage current drifts and electrocatalytic response free differential pulse voltammetric pH sensor applications. A poly(4 chloroaniline) modified graphitized mesoporous carbon electrode has been prepared for an efficient redox active system for voltage current drifts and electrocatalytic response free differential pulse voltammetric pH sensor applications.", "author_names": [ "Sairaman Saikrithika", "Annamalai Senthil Kumar" ], "corpus_id": 233465787, "doc_id": "233465787", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A selective voltammetric pH sensor using graphitized mesoporous carbon/polyaniline hybrid system", "venue": "Journal of Chemical Sciences", "year": 2021 }, { "abstract": "A temperature self calibrated potential of hydrogen (pH) sensor based on the single mode fiber tapered dual core photonic crystal fiber single mode fiber (SMF TDCPCF SMF) structure cascaded with a fiber Bragg grating (FBG) is proposed and demonstrated. The TDCPCF structure formed Mach Zehnder interferometer (MZI) is modified with a coating of graphene oxide/polyvinyl alcohol (GO/PVA) hybrid hydrogel to realize the measurement of pH, and the uncoated FBG is used to calibrate temperature. In our experiment, the sensitivity coefficient of 0.69 nm/pH with R2=0.99 and the hysteresis loss of less than 0.007 are achieved within the pH range from pH 4.00 to pH 9.85. The measured response time from pH 7.00 to pH 4.00, 6.00 and 9.85 are no higher than 10s. Moreover, the resonant wavelengths of MZI and FBG also exhibit good linear relationship with the temperature sensitivity coefficient of 0.15 nm/degC (R2=0.99) and 0.09 nm/degC (R2=0.97) respectively. It is demonstrated successfully that the proposed sensor has broad application prospects in the field of environmental monitoring, biological sensing and chemical analysis, due to the good performance of the temperature self calibrated pH monitoring, repeatability, linearity, response time and reversibility.", "author_names": [ "Ran Yan", "Guofeng Sang", "Bin Yin", "Songhua Wu", "Muguang Wang", "Benran Hou", "Ming-Cian Gao", "Rong Chen", "Han Yu" ], "corpus_id": 233608632, "doc_id": "233608632", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Temperature self calibrated pH sensor based on GO/PVA coated MZI cascading FBG.", "venue": "Optics express", "year": 2021 }, { "abstract": "Development of a biocompatible pH sensor is of importance in biomedical applications, particularly for in vivo measurement, providing necessary information for clinical diagnosis and treatment such as chronic wounds and foetal acidosis. Traditional pH indicator based optical sensors have problems of dye leaching and photobleaching that restrict their uses in long term monitoring. In this work, a dye free fibre optic pH sensor is proposed consisting of a U shape multimode optical fibre coated with a hybrid organic inorganic composite film. The film is formed by cross linking ethyl cellulose with a silica matrix at an optimised ethyl cellulose/silica molar ratio of 0.0065 via weakly interacted hydrogen bonding. This bonding is affected by hydrogen concentration (i.e. pH) in a solution resulting in a morphological change of the polymer aggregation presented in the silica matrix leading to refractive index change of the film. The developed sensor shows a reversible response to pH from 4.5 to 12.5 and exhibits linear correlation between transmitted light power and pH with a limit of agreement (LoA) between the sensor and a commercial probe of 0.2 pH. For a clinically important range of pH values between 6 and 8 the LoA is 0.1 pH. The sensor has low cross sensitivity to temperature as the maximum interpreted pH change attributed to the power change is 0.12 pH when the temperature changes from 21 degC to 39 degC. To demonstrate biomedical relevance, the sensor is used to monitor pH of human serum. An in house cytotoxicity assay is conducted with mouse fibroblast cell revealing that the film is not cytotoxic.", "author_names": [ "Zijuan Tang", "David Gomez", "Chenyang He", "Serhiy Korposh", "Stephen P Morgan", "Ricardo Correia", "Barrie R Hayes-Gill", "Kerry Setchfield", "Liangliang Liu" ], "corpus_id": 229266520, "doc_id": "229266520", "n_citations": 1, "n_key_citations": 1, "score": 0, "title": "A U Shape Fibre Optic pH Sensor Based on Hydrogen Bonding of Ethyl Cellulose With a Sol Gel Matrix", "venue": "Journal of Lightwave Technology", "year": 2021 }, { "abstract": "Abstract Fluorescence intensity of carbon nanomaterials (CNMs) synthesized with ethanolamine hardly changed with pH value. Doping Zinc into CNMs improved optical properties of CNMs. On the one hand, the fluorescence quantum yield of CNMs increased, on the other hand, the fluorescence intensity of Zn doped CNMs decreased with pH value. Coupling Zn doped CNMs with ZnCdS quantum dots (QDs) as a dual emission system, the blue fluorescence intensity of CNMs (I450) decreased while the orange fluorescence intensity of QDs (I580) enhanced with pH value increasing. The ratio (I450/I580) varied linearly with pH value in the range of 1 9 and correlation coefficient (R2) was 0.991. Furthermore, using the system as a ratiometric fluorescence pH sensor to determine ascorbic acid, a good linear relationship (R2 0.998) was found when the concentration of ascorbic acid ranged from 0 1600 mM and limit of detection (LOD) was as low as 0.082 mM.", "author_names": [ "Yinyin Chen", "Xianxiang Wang" ], "corpus_id": 236285375, "doc_id": "236285375", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "New properties of carbon nanomaterials through zinc doping and application as a ratiometric fluorescence pH sensor", "venue": "", "year": 2021 }, { "abstract": "This paper describes a pH sensor for soil monitoring that is composed of fully biodegradable materials in the soil. Our biodegradable pH sensor is composed of only two key elements: One is a magnesium electromagnetic antenna that dissolves in water, and the other is a protection layer of hydroxyapatite that decomposes in response to pH. This sensor works as an electromagnetic split ring resonator (metamaterial) that reflects electromagnetic waves with specific frequency in GHz band, enabling in wireless remote sensing without any electric circuits or batteries. We demonstrated wireless pH detection of soil for aiming to realize an environmentally friendly monitoring sensor that does not require collection after installation.", "author_names": [ "Katsutoshi Hori", "Ayaka Inami", "Tetsuo Kan", "Hiroaki Onoe" ], "corpus_id": 236940014, "doc_id": "236940014", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Split Ring Shaped Biodegradable pH Sensor for Wireless and Battery Free Monitoring of Agricultural Fields", "venue": "2021 21st International Conference on Solid State Sensors, Actuators and Microsystems (Transducers)", "year": 2021 }, { "abstract": "This paper presents an analytical model of AlGaN/GaN MOS HEMT based pH sensor for the first time to determine pH of different electrolyte solutions. Gouy chapman stern model has been used to calculate the surface charge density. The results obtained using analytical model have been verified and show good agreement with the simulated results. Cavity length, thickness of AlGaN barrier layer and Al composition have been optimized to improve the sensitivity of the device. It has been observed that the drain current and threshold voltage decreases with increase in pH of the electrolytic solutions. Proposed AlGaN/GaN MOS HEMT sensor demonstrate a quick response to the pH changes. The maximum drain on sensitivity of the device is 132mA/mm pH. Surface potential and threshold voltage sensitivity of 0.95mV/pH and 950mV/pH respectively have been obtained which is much higher than the Nernstian limit(59.2mV/pH)", "author_names": [ "Praveen Pal", "Yogesh Pratap", "Mridula Gupta", "Sneha Kabra" ], "corpus_id": 234192832, "doc_id": "234192832", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Analytical Modeling and Simulation of AlGaN/GaN MOS HEMT for High Sensitive pH Sensor", "venue": "IEEE Sensors Journal", "year": 2021 }, { "abstract": "To improve the stability and sensitivity of pH sensors based on AlGaN/GaN high electron mobility transistors (HEMTs) we proposed a modified sensing structure by integrating a reference HEMT device. This structural pH sensor exhibits a typical Nernstian behavior with a sensitivity of 54.38 mV/pH, which is higher than the value of 49.43mV/pH derived from the AlGaN/GaN HEMT based sensor without integrating the reference HEMTs device. Furthermore, the stability of the new structural sensor is enhanced by approximately 19.2% in comparison with that of its traditional counterpart. The improved performances are analyzed using an electrical double layer model together with an equivalent circuit model, and we find that the new sensor structure has a larger capacitor and exhibits a better rectification effect, hence decreasing the electrical noise and enhancing the stability of the testing signal. Meanwhile, the new sensor structure displays a smaller equivalent resistance and results in a larger available output current, hence exhibiting a higher sensitivity.", "author_names": [ "Zi Li Xie", "Yanli Liu", "Jianming Lei", "Hui Guo", "Quan Dai", "Jeong-Gil Kim", "Seung-Hyeon Kang", "C -H Won", "Jung-Hee Lee", "Dunjun Chen", "Rong Zhang", "Youdou Zheng" ], "corpus_id": 232316317, "doc_id": "232316317", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Enhanced Stability and Sensitivity of AlGaN/GaN HEMTs pH Sensor by Reference Device", "venue": "IEEE Sensors Journal", "year": 2021 } ]

[ { "abstract": "Abstract In industrial catalysis, the sintering of supported nanoparticles (NPs) is often associated with the loss of catalyst activity and thus with periodic plant downtime and economic burdens. Yet, sintering mechanisms are at play also during the synthesis of the catalyst itself. They can, in fact, determine the size distribution of the NPs, and thus the activity and the stability of the catalyst. Here, we examine the role of nanoparticle sintering in a technique borrowed from the semiconductor industry that promises to reconcile atomic scale precision with scalability: atomic layer deposition. By modeling the cyclic influx of single atoms in concomitance with NP sintering via either dynamic coalescence or Ostwald ripening, we establish the \"signature\" of different growth regimes: the size distribution. In contrast, we show that integral quantities such as the mean diameter, the number of NPs per unit area, and the material loading are poor indicators of the underlying growth mechanism. In particular, a constant number of NPs cannot be interpreted as a sign of no sintering. Finally, we argue that NP sintering, if properly understood, can open up new avenues for the control over the size distribution of NPs, and thus over their catalytic activity and stability.", "author_names": [ "Fabio Grillo", "Jacob A Moulijn", "Michiel T Kreutzer", "J Ruud van Ommen" ], "corpus_id": 104273521, "doc_id": "104273521", "n_citations": 26, "n_key_citations": 1, "score": 1, "title": "Nanoparticle sintering in atomic layer deposition of supported catalysts: Kinetic modeling of the size distribution", "venue": "", "year": 2018 }, { "abstract": "Calorimetric measurements of metal adsorption energies directly provide the energies of metal atoms in supported metal nanoparticles. As the metal coverage increases, the particles grow, revealing the dependence of this energy on particle size, which is found to be much stronger than predicted with the usual Gibbs Thompson relation. It is shown that this knowledge is crucial to accurately model long term sintering rates of metal nanoparticles in catalysts.", "author_names": [ "Charles T Campbell", "Stephen C Parker", "David E Starr" ], "corpus_id": 45008806, "doc_id": "45008806", "n_citations": 749, "n_key_citations": 4, "score": 0, "title": "The Effect of Size Dependent Nanoparticle Energetics on Catalyst Sintering", "venue": "Science", "year": 2002 }, { "abstract": "This dissertation examines growth of platinum nanoparticles from vapor deposition on SrTiO 3 using a characterization approach that combines imaging techniques and X ray methods. The primary suite of characterization probes includes atomic force microscopy (AFM) grazing incidence small angle X ray scattering (GISAXS) X ray fluorescence (XRF) scanning electron microscopy (SEM) and X ray absorption spectroscopy (XAS) The vapor deposition techniques include physical vapor deposition (PVD) by evaporation and atomic layer deposition (ALD) For the PVD platinum study, AFM/XRF showed ~10 nm nanoparticles separated by an average of 100 nm. The combination of AFM, GISAXS, and XRF indicated that the nanoparticles observed with AFM were actually comprised of closely spaced, smaller nanoparticles. These conclusions were supported by high resolution SEM. The unusual behavior of platinum nanoparticles to aggregate without coalescence or sintering was observed previously by other researchers using transmissision electron microscopy (TEM) Platinum nanoparticle growth was also investigated on SrTiO 3 (001) single crystals using ALD to nucleate nanoparticles that subsequently grew and coalesced into granular films as the ALD progresses. The expected growth rate for the early stages of ALD showed a twofold increase which was attributed to the platinum deposition occurring faster on the bare substrate. Once the nanoparticles had coalesced into a film, steady state ALD growth proceeded. The formation of nanoparticles was attributed to the atomic diffusion of platinum atoms on iv the surface in addition to direct growth from the ALD precursor gases. The platinum ALD nanoparticles were also studied on SrTiO 3 nanocube powders. The SrTiO 3 nanocubes average 60 nm on a side and the cube faces have a {001} orientation. The ALD proceeded in a similar fashion as on the single crystal substrates where the deposition rate was twice as fast as the steady state growth rate. The Pt nanoparticle size increased linearly starting at ~0.7 nm for 1 ALD cycle to ~3 nm for 5 ALD cycles. The platinum chemical state was also investigated using X ray absorption spectroscopy. Platinum nanoparticles ~1 nm or smaller tended to be oxidized. For larger nanoparticles, the platinum state systematically approached that of bulk platinum metal as the size (number of ALD cycles) increased. The platinum loading was exceptionally low, 10 3 mg cm 2. v ACKNOWLEDGEMENT The counsel to \" do something difficult for my posterity \" was once given to me. This work would not have been possible without the help from many collaborators, friends, and loved ones. I will", "author_names": [ "Steven T Christensen" ], "corpus_id": 102104371, "doc_id": "102104371", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Nanoscale investigation of platinum nanoparticles on SrTiO3 grown via physical vapor deposition and atomic layer deposition", "venue": "", "year": 2008 }, { "abstract": "This paper discusses the mechanisms of surface area loss of supported platinum (Pt) electrocatalysts in low temperature fuel cells. It is argued that submonolayer dissolution of Pt nanoparticles governs the surface area loss at high voltages by increasing the loss of Pt from carbon and coarsening of Pt nanoparticles on carbon.", "author_names": [ "Yang Shao-Horn", "Wenchao Sheng", "Shen Chen", "Paulo J T Ferreira", "Edward F Holby", "D Morgan" ], "corpus_id": 39013998, "doc_id": "39013998", "n_citations": 708, "n_key_citations": 10, "score": 0, "title": "Instability of Supported Platinum Nanoparticles in Low Temperature Fuel Cells", "venue": "", "year": 2007 }, { "abstract": "We review here our studies of the reactivity and sintering kinetics of model catalysts consisting of gold nanoparticles dispersed on TiO2(110) First, the nucleation and growth of vapor deposited gold on this surface was experimentally examined using x ray photoelectron spectroscopy and low energy ion scattering. Gold initially grows as two dimensional islands up to a critical coverage, thcr, after which 3D gold nanoparticles grow. The results at different temperatures are fitted well with a kinetic model, which includes various energetic parameters for Au adatom migration. Oxygen was dosed onto the resulting gold nanoparticles using a hot filament technique. The desorption energy of Oa was examined using temperature programmed desorption (TPD) The Oa is bonded ~40% more strongly to smaller (thinner) Au islands. Gaseous CO reacts rapidly with this Oa to make CO2, probably via adsorbed CO. The reactivity of Oa with CO increases with increasing particle size, as expected based on Bronsted relations. Propene adsorption leads to TPD peaks for three different molecularly adsorbed states on Au/TiO2(110) corresponding to propene adsorbed on gold islands, to Ti sites on the substrate, and to the perimeter of gold islands, with adsorption energies of 40, 52 and 73 kJ/mol, respectively. Thermal sintering of the gold nanoparticles was explored using temperature programmed low energy ion scattering. These sintering rates for a range of Au loadings at temperatures from 200 to 700 K were well fitted by a theoretical model which takes into consideration the dramatic effect of particle size on metal chemical potential using a modified bond additivity model. When extrapolated to simulate isothermal sintering at 700 K for 1 year, the resulting particle size distribution becomes very narrow. These results question claims that the shape of particle size distributions reveal their sintering mechanisms. They also suggest why the growth of colloidal nanoparticles in liquid solutions can result in very narrow particle size distributions.", "author_names": [ "Stephen C Parker", "Charles T Campbell" ], "corpus_id": 53646786, "doc_id": "53646786", "n_citations": 70, "n_key_citations": 1, "score": 0, "title": "Reactivity and sintering kinetics of Au/TiO2(110) model catalysts: particle size effects", "venue": "", "year": 2007 }, { "abstract": "A kinetic model for the sintering of metal particles on oxide or other support surfaces is derived and applied to simulate experimental measurements of the sintering of a model gold catalyst: gold nanoparticles supported on \\mathrm{TiO}}_{2}(110) It follows the pioneering work of Wynblatt and Gjostein (WG) Progress in Solid State Chemistry (1975, p. 21) but removes several important assumptions that create dramatic errors in sintering rates for particles smaller than $6\\phantom{\\rule{0.3em}{0ex}\\mathrm{nm} in diameter, including (1) use of the Gibbs Thomson relation assuming that the surface free energy of metal particles is independent of size, and (2) neglect of all but the first order terms in a Taylor series expansion. Recent microcalorimetry measurements have shown these assumptions to be untrue in that metal particles smaller than $6\\phantom{\\rule{0.3em}{0ex}\\mathrm{nm} have much higher surface free energies than large particles. A modified bond additivity model more accurately estimates particle energy versus size. This estimate was incorporated into the kinetic model of WG and applied to simulate the sintering of Au particles on \\mathrm{TiO}}_{2}(110) as measured by temperature programmed low energy ion scattering. Our model reproduces well the broad temperature range over which sintering typically occurs in such experiments. This is analogous to accurate modeling of long term sintering kinetics of metal nanoparticles under the isothermal conditions of real catalysis. These results also highlight problems with classical methods for determining the sintering mechanism based solely upon the shape of the sintered particle size distribution.", "author_names": [ "Stephen C Parker", "Charles T Campbell" ], "corpus_id": 96177543, "doc_id": "96177543", "n_citations": 118, "n_key_citations": 0, "score": 0, "title": "Kinetic model for sintering of supported metal particles with improved size dependent energetics and applications to Au on TiO 2 110", "venue": "", "year": 2007 }, { "abstract": "Recently, small particles have been shown to exhibit a melting temperature which depends on the particle size. The various possible experimental methods have been compared and measurements of the melting points of small gold particles have been made using a scanning electron diffraction technique. This method was applied to particles having diameters down to 20 \\AA{ Consideration of the size distribution over an entire sample makes it necessary to carry out a careful analysis of the experimental results in order to deduce the melting temperature of particles having a well defined diameter. The experimental results are quantitatively in good agreement with two phenomenological models. The first model describes the equilibrium condition for a system formed by a solid particle, a liquid particle having the same mass, and their saturating vapor phase. The second model assumes the preexistence of a liquid layer surrounding the solid particle and describes the equilibrium of such a system in the presence of the vapor phase. In order to permit a better comparison between both models, a new expression for the thermodynamic equilibrium condition has been derived in the present work. In the case of the first model, the agreement was obtained using only the physical constants of massive gold. In applying the second model, however, one is compelled to assume the existence of a liquid layer having a thickness of about 6 \\AA{", "author_names": [ "Philippe A Buffat", "J P Borel" ], "corpus_id": 122735625, "doc_id": "122735625", "n_citations": 2693, "n_key_citations": 23, "score": 0, "title": "Size effect on the melting temperature of gold particles", "venue": "", "year": 1976 }, { "abstract": "Exciting new opportunities are emerging in the field of catalysis based on nanotechnology approaches. A new understanding and mastery of catalysis could have broad societal impacts, since about 80% of the processes in the chemical industry depend on catalysts to work efficiently. Efforts in surface science have led to the discovery of new heterogeneous catalysts, however, until recently the only way to develop new or improved catalysts was by empirical testing in trial and error experiments. This time consuming and costly procedure is now rapidly being replaced by rational design methods that utilize fundamental knowledge of catalysts at the nanoscale. The advent of nanoscience and nanotechnology is providing the ability to create controlled structures and geometries to investigate and optimize a broad range of catalytic processes. As a result, researchers are obtaining fundamental insight into key features that influence the activity, selectivity, and lifetime of nanocatalysts. This review article examines several new findings as well as current challenges in the field of nanoparticle based catalysis, including the role played by the particle structure and morphology (size and shape) its chemical composition and oxidation state, and the effect of the cluster support.", "author_names": [ "Beatriz Roldan Cuenya" ], "corpus_id": 31006712, "doc_id": "31006712", "n_citations": 806, "n_key_citations": 6, "score": 0, "title": "Synthesis and catalytic properties of metal nanoparticles: Size, shape, support, composition, and oxidation state effects", "venue": "", "year": 2010 }, { "abstract": "Abstract Chemical Vapour Deposition (CVD) of films and coatings involve the chemical reactions of gaseous reactants on or near the vicinity of a heated substrate surface. This atomistic deposition method can provide highly pure materials with structural control at atomic or nanometer scale level. Moreover, it can produce single layer, multilayer, composite, nanostructured, and functionally graded coating materials with well controlled dimension and unique structure at low processing temperatures. Furthermore, the unique feature of CVD over other deposition techniques such as the non line of sight deposition capability has allowed the coating of complex shape engineering components and the fabrication of nano devices, carbon carbon (C C) composites, ceramic matrix composite (CMCs) free standing shape components. The versatility of CVD had led to rapid growth and it has become one of the main processing methods for the deposition of thin films and coatings for a wide range of applications, including semiconductors (e.g. Si, Ge, Si 1 x Ge x III V, II VI) for microelectronics, optoelectronics, energy conversion devices; dielectrics (e.g. SiO 2 AlN, Si 3 N 4 for microelectronics; refractory ceramic materials (e.g. SiC, TiN, TiB 2 Al 2 O 3 BN, MoSi 2 ZrO 2 used for hard coatings, protection against corrosion, oxidation or as diffusion barriers; metallic films (e.g. W, Mo, Al, Au, Cu, Pt) for microelectronics and for protective coatings; fibre production (e.g. B and SiC monofilament fibres) and fibre coating. This contribution aims to provide a brief overview of CVD of films and coatings. The fundamental aspects of CVD including process principle, deposition mechanism, reaction chemistry, thermodynamics, kinetics and transport phenomena will be presented. In addition, the practical aspects of CVD such as the CVD system and apparatus used, CVD process parameters, process control techniques, range of films synthesized, characterisation and co relationships of structures and properties will be presented. The advantages and limitations of CVD will be discussed, and its applications will be briefly reviewed. The article will also review the development of CVD technologies based on different heating methods, and the type of precursor used which has led to different variants of CVD methods including thermally activated CVD, plasma enhanced CVD, photo assisted CVD, atomic layer epitaxy process, metalorganic assisted CVD. There are also variants such as fluidised bed CVD developed for coating powders; electrochemical vapour deposition for depositing dense films onto porous substrates; chemical vapour infiltration for the fabrication of C C composites and CMCs through the deposition and densification of ceramic layers onto porous fibre preforms. The emerging cost effective CVD based techniques such as electrostatic aerosol assisted CVD and flame assisted CVD will be highlighted. The scientific and technological significance of these different variants of CVD will be discussed and compared with other vapour processing techniques such as Physical Vapour Deposition.", "author_names": [ "Kwang-Leong Choy" ], "corpus_id": 138473142, "doc_id": "138473142", "n_citations": 1218, "n_key_citations": 42, "score": 0, "title": "Chemical vapour deposition of coatings", "venue": "", "year": 2003 }, { "abstract": "The terraces, edges, and facets of nanoparticles are all active sites for heterogeneous catalysis. These different active sites may cause the formation of various products during the catalytic reaction. Here we report that the step sites of Pd nanoparticles (NPs) can be covered precisely by the atomic layer deposition (ALD) method, whereas the terrace sites remain as active component for the hydrogenation of furfural. Increasing the thickness of the ALD generated overcoats restricts the adsorption of furfural onto the step sites of Pd NPs and increases the selectivity to furan. Furan selectivities and furfural conversions are linearly correlated for samples with or without an overcoating, though the slopes differ. The ALD technique can tune the selectivity of furfural hydrogenation over Pd NPs and has improved our understanding of the reaction mechanism. The above conclusions are further supported by density functional theory (DFT) calculations.", "author_names": [ "Hongbo Zhang", "Xiang-Kui Gu", "Christian P Canlas", "A Jeremy Kropf", "Payoli Aich", "Jeffrey P Greeley", "Jeffrey W Elam", "Randall J Meyers", "James A Dumesic", "Peter C Stair", "Christopher L Marshall" ], "corpus_id": 5119863, "doc_id": "5119863", "n_citations": 58, "n_key_citations": 0, "score": 0, "title": "Atomic layer deposition overcoating: tuning catalyst selectivity for biomass conversion.", "venue": "Angewandte Chemie", "year": 2014 } ]

[ { "abstract": "", "author_names": [ "M Mitchell Waldrop" ], "corpus_id": 4464555, "doc_id": "4464555", "n_citations": 1000, "n_key_citations": 20, "score": 1, "title": "The chips are down for Moore's law", "venue": "Nature", "year": 2016 }, { "abstract": "vii Table of", "author_names": [ "John Kowalski" ], "corpus_id": 107265561, "doc_id": "107265561", "n_citations": 3, "n_key_citations": 1, "score": 0, "title": "Industry Location Shift through Technological Change A Study of the US Semiconductor Industry (1947 1987)", "venue": "", "year": 2012 }, { "abstract": "Electrifying in its simplicity like all great breakthroughs COMPETITIVE STRATEGY captures the complexity of industry competition in five underlying forces. Author Michael Porter introduces one of the most powerful competitive tools yet developed: his three generic strategies lowest cost, differentiation, and focus which bring structure to the task of strategic positioning. He shows how competitive advantage can be defined in terms of relative cost and relative prices, thus linking it directly to profitability, and presents a whole new perspective on how profit is created and divided. More than a million managers in both large and small companies, investment analysts, consultants, students, and scholars throughout the world have internalised Porter's ideas and applied them to assess industries, understand competitors and choose competitive positions. COMPETITIVE STRATEGY has filled a void in management thinking. It provides an enduring foundation and grounding point on which all subsequent work can be built. Porter's rich frameworks and deep insights comprise a sophisticated view of competition unsurpassed in the last quarter century.", "author_names": [ "Michael E Porter" ], "corpus_id": 108873179, "doc_id": "108873179", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Competitive strategy techniques for analyzing industries and competitors with a new introduction", "venue": "", "year": 1980 }, { "abstract": "", "author_names": [ "Ronald Bailey" ], "corpus_id": 150907126, "doc_id": "150907126", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Scrutinizing Industry Funded Science: The Crusade Against Conflicts of Interest", "venue": "", "year": 2008 }, { "abstract": "This Article offers a systematic examination of trade law's responses to the emergence of China as a major player in world trade. As an intricate set of rules written largely prior to the advent of the China era, trade law had to readjust to the powerful newcomer in ways that eventually changed trade law itself. This Article investigates these changes in four major areas of trade law: antidumping, countervailing duties, safeguards, and managed trade. In almost all of those areas, trade law witnessed a protectionist shift against Chinese products at the expense of sound, consistent principles. But, at the same time, trade law has corrected some of the most egregious protectionist policies on China. These adaptations on the part of trade law tell a story of how an organic legal system evolves in response to changing external circumstances. This Article concludes that at least as an initial assessment, trade law has been rather successful in accommodating China in the new world trade order and has preserved the structural stability of the world trade system without deviating too far from its core principles.", "author_names": [ "Wentong Zheng" ], "corpus_id": 157670435, "doc_id": "157670435", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Trade Law's Responses to the Rise of China", "venue": "", "year": 2016 }, { "abstract": "Reports in 1982 of polymers ablated and etched by excimer laser radiation mark the founding of laser microfabrication as a technology that in the intervening period has matured into a manufacturing process used by a diverse range of industries. This paper reviews the historical developments of laser microfabrication, highlights some of its current important industrial applications and takes a forward look at possible developments of the technology.", "author_names": [ "Malcolm C Gower" ], "corpus_id": 120788883, "doc_id": "120788883", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Laser microfabrication in industry perspectives from the past, present and future", "venue": "SPIE LASE", "year": 2008 }, { "abstract": "Over the last two decades 'nanotechnology' a term applied to both scientific research and disparate new and emerging technologies, has become an important focus of science policy and controversy. Its emergence has been marked by hyperbolic expectations of breakthroughs and general prominence of representations of the future (e.g. speculative visions) The purpose of this study was to assess the evolving trajectory and dynamics of nanotechnology in Australia, with a focus on these future oriented aspects and the promising of new technological options. Additional aims were to investigate the associated social shaping, i.e. taking place 'upstream' and disputes about nanotechnology development. An interdisciplinary approach was used drawing primarily on literature from science and technology studies (STS) on relevant socio technical dynamics (such as the role of expectations in and about science and technology) and 'science and society' as well as environmental politics and innovation studies. Relevant data was primarily gained through anonymous interviews with 30 'opinion leaders' from relevant sectors (i.e. research community, industry and research commercialisation, public sector, and civil society) This data was combined with publicly available information on nanotechnology activities and investment. This research shows in contrast to most reports and analysis that a significant weakening of nanotechnology expectations and decline in commercialisation activity has emerged. Expectations and assessments of nanotechnology by proponents and opponents also sharply diverge in relation to its potential roles in addressing environmental problems, such as climate change, and other sustainability issues. In this way, responses to nanotechnology have in part been shaped by environmental discourses, which influence the framing of these problems and associated desired solutions by engaged actors and consideration of technological risks. Also identified are pressures that led to overpromising which contributed to problematic socio political dynamics hindering efforts to realise these promises. The identified trajectory and dynamics: support STS research theorising the governance of technology by expectations (a 'de facto' form, i.e. extending beyond formal policy/regulatory interventions) is consistent with recent STS research that has identified the increasing importance of broader 'innovation governance' aimed at more purposeful, sociallyagreed technological choices and innovation trajectories; and, indicates how, and in part why, the Federal Government's 'responsible development' of nanotechnology objectives have not been achieved to date. The identified drivers of controversy are also likely to lead to future disputes in additional emerging areas of science and technology (e.g. synthetic biology)", "author_names": [ "Stephen Mcgrail" ], "corpus_id": 114947101, "doc_id": "114947101", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Promising, contesting and abandoning nanotechnology: dynamics of unrealised promises, expectations, and engagement with nanotechnology in the Australian context", "venue": "", "year": 2011 }, { "abstract": "On different levels and with different strategic importance, business managers face technology decisions every day. These decisions concern not only which technologies to use, but also which ones n", "author_names": [ "Jens Hultman" ], "corpus_id": 166559892, "doc_id": "166559892", "n_citations": 23, "n_key_citations": 1, "score": 0, "title": "Rethinking adoption Information and communications technology interaction processes within the Swedish automobile industry", "venue": "", "year": 2007 }, { "abstract": "The future of integrated electronics is the future of electronics itself. The advantages of integration will bring about a proliferation of electronics, pushing this science into many new areas. Integrated circuits will lead to such wonders as home computers or at least terminals connected to a central computer automatic controls for automobiles, and personal portable communications equipment. The electronic wristwatch needs only a display to be feasible today. But the biggest potential lies in the production of large systems. In telephone communications, integrated circuits in digital filters will separate channels on multiplex equipment. Integrated circuits will also switch telephone circuits and perform data processing. Computers will be more powerful, and will be organized in completely different ways. For example, memories built of integrated electronics may be distributed throughout the machine instead of being concentrated in a central unit. In addition, the improved reliability made possible by integrated circuits will allow the construction of larger processing units. Machines similar to those in existence today will be built at lower costs and with faster turnaround.", "author_names": [ "Gordon E Moore" ], "corpus_id": 6519532, "doc_id": "6519532", "n_citations": 10411, "n_key_citations": 444, "score": 0, "title": "Cramming More Components Onto Integrated Circuits", "venue": "Proceedings of the IEEE", "year": 1998 }, { "abstract": "Japan U.S. Educational Commission (Fulbright Commission) Cornell East Asia Program German Academic Exchange Service", "author_names": [ "Aaron Stephen Moore" ], "corpus_id": 161109635, "doc_id": "161109635", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "The Technological Imaginary of Imperial Japan, 1931 1945", "venue": "", "year": 2006 } ]

[ { "abstract": "The electronic and optical properties and the recent progress in applications of 2D semiconductor transition metal dichalcogenides with emphasis on strong excitonic effects, and spin and valley dependent properties are reviewed.", "author_names": [ "Kin Fai Mak", "Jie Shan" ], "corpus_id": 124091327, "doc_id": "124091327", "n_citations": 1769, "n_key_citations": 14, "score": 1, "title": "Photonics and optoelectronics of 2D semiconductor transition metal dichalcogenides", "venue": "", "year": 2016 }, { "abstract": "Two dimensional transition metal dichalcogenides (2D TMDs) have attracted attention for applications in electronics and photonics, as well as for the wealth of new scientific phenomena that arise at low dimensionality. Recently, the ability to grow 2D TMDs by chemical vapor deposition has opened the path to large area devices, but also to the synthesis of semiconductor alloys with tunable bandgaps. In this presentation, I will discuss our recent experimental work in exploring the optoelectronic properties of 2D MoS_2(1 x)Se_2x alloys spanning the compositional range. In particular, we report the observation of a new regime of operation where the photocurrent depends superlinearly on light intensity. We use spatially resolved photocurrent measurements on devices consisting of CVD grown monolayers to show the photoconductive nature of the photoresponse, with the photocurrent dominated by recombination and field induced carrier separation in the channel. Time dependent photoconductivity measurements show the presence of persistent photoconductivity for the S rich alloys, while photocurrent measurements at fixed wavelength for devices of different alloy compositions show a systematic decrease of the responsivity with increasing Se content associated with increased linearity of the current voltage characteristics. A model based on the presence of different types of recombination centers is presented to explain the origin of the superlinear dependence on light intensity, which emerges when the non equilibrium occupancy of initially empty fast recombination centers becomes comparable to that of slow recombination centers.", "author_names": [ "Francois Leonard" ], "corpus_id": 124615784, "doc_id": "124615784", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Optoelectronics in two dimensional semiconductor alloys (Presentation Recording)", "venue": "SPIE NanoScience Engineering", "year": 2015 }, { "abstract": "Monolayer two dimensional transition metal dichalcogenides (2D TMDCs) have gained immense attention for their desirable transport properties and direct bandgap that have led to a plethora of studies on modern nanoelectronic and optoelectronic applications. These properties are known to occur exclusively in TMDCs when thinned down to one or few monolayers. However reduced dimensionality poses a significant challenge for photonics and optoelectronics applications due to poor light absorption and emission dictated by the volume of semiconductor material. Plasmonic nanostructures have been widely studied for enhancing light matter interactions in wide variety of material systems resulting in increased emission and absorption properties. 2D Materials provide the ultimate lower limit in terms of material thickness, therefore investigation of plasmon/2D Material hybrid material systems with a specific aim to enhance light matter interactions is essential for practical optoelectronic applications. In this talk, I will discuss increased photoluminescence emission from MoS2 using both periodic plasmonic nanodisc arrays as well as a single plasmonic optical antenna. I will also describe a method for understanding and identifying the contributions of excitation and emission field enhancements to the overall photoluminescence enhancement using a tapered gold antenna. Additionally, I will describe a systematic study in which we have demonstrated increased light absorption in a monolayer WS2 film.", "author_names": [ "Koray Aydin" ], "corpus_id": 139181528, "doc_id": "139181528", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Plasmonics meet 2D materials: enhanced light matter interactions in the flatland (Conference Presentation)", "venue": "", "year": 2018 }, { "abstract": "Monolayer two dimensional transition metal dichalcogenides (2D TMDCs) have gained immense attention for their desirable transport properties and direct bandgap that have led to a plethora of studies on modern nanoelectronic and optoelectronic applications. These properties are known to occur exclusively in TMDCs when thinned down to one or few monolayers. However reduced dimensionality poses a significant challenge for photonics and optoelectronics applications due to poor light absorption and emission dictated by the volume of semiconductor material. Plasmonic nanostructures have been widely studied for enhancing light matter interactions in wide variety of material systems resulting in increased emission and absorption properties. 2D Materials provide the ultimate lower limit in terms of material thickness, therefore investigation of plasmon/2D Material hybrid material systems with a specific aim to enhance light matter interactions is essential for practical optoelectronic applications. In this talk, I will discuss increased photoluminescence emission from MoS2 using both periodic plasmonic nanodisc arrays as well as a single plasmonic optical antenna. Additionally, I will describe a systematic study in which we have demonstrated increased light absorption in a monolayer WS2 film.", "author_names": [ "Koray Aydin" ], "corpus_id": 139964467, "doc_id": "139964467", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Efficient light emission and absorption in monolayer 2D semiconductors using plasmonic nanostructures (Conference Presentation)", "venue": "", "year": 2018 }, { "abstract": "Abstract Two dimensional (2D) van der Waals (vdW) nanosheet semiconductors have recently attracted much attention from researchers because of their potentials as active device materials toward future nano electronics and optoelectronics. This review focuses on the performance and applications of state of the art vdW 2D material devices which use transition metal dichalcogenides, graphene, hexagonal boron nitride (h BN) and black phosphorous: field effect transistors (FETs) complementary metal oxide semiconductor (CMOS) inverters, Schottky diode, and PN diode. High mobility in FETs, electrical switching dynamics in CMOS inverter, photovoltaic switching for dynamic energy harvesting in PN diode, and high current driving FETs for organic light emitting diode pixel switching are demonstrated, however, remaining important issues for future electronics and photonics applications are also introduced. As a final contribution of this review, the ultimate orientations for future applications of 2D devices are forecasted and suggested, which are toward ubiquitous electronics to be a part of internet of things as integrated with existing semiconductor devices.", "author_names": [ "Kyunghee Choi", "Young Tack Lee", "Seongil Im" ], "corpus_id": 138103917, "doc_id": "138103917", "n_citations": 61, "n_key_citations": 0, "score": 0, "title": "Two dimensional van der Waals nanosheet devices for future electronics and photonics", "venue": "", "year": 2016 }, { "abstract": "Monolayer two dimensional transition metal dichalcogenides (2D TMDCs) have gained immense attention for their desirable transport properties and direct bandgap that have led to a plethora of studies on modern nanoelectronic and optoelectronic applications. These properties are known to occur exclusively in TMDCs when thinned down to one or few monolayers. However reduced dimensionality poses a significant challenge for photonics and optoelectronics applications due to poor light absorption and emission dictated by the volume of semiconductor material. Plasmonic nanostructures have been widely studied for enhancing light matter interactions in wide variety of material systems resulting in increased emission and absorption properties. 2D Materials provide the ultimate lower limit in terms of material thickness, therefore investigation of plasmon/2D Material hybrid material systems with a specific aim to enhance light matter interactions is essential for practical optoelectronic applications. In this talk, I will discuss increased photoluminescence emission from MoS2 using both periodic plasmonic nanodisc arrays as well as a single plasmonic optical antenna. I will also describe a method for understanding and identifying the contributions of excitation and emission field enhancements to the overall photoluminescence enhancement using a tapered gold antenna. Additionally, I will describe a systematic study in which we have demonstrated increased light absorption in a monolayer WS2 film.", "author_names": [ "Koray Aydin", "Nobuhiko Palo Alto Kobayashi", "A Alec Talin", "Albert V Davydov", "M Saif Islam" ], "corpus_id": 103463533, "doc_id": "103463533", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Plasmon enhanced photon emission and absorption in monolayer, two dimensional semiconductors (Conference Presentation)", "venue": "", "year": 2017 }, { "abstract": "In the growing list of 2D semiconductors as potential successors to silicon in future devices, metal halide perovskites have recently joined the family. Unlike other conversional 2D covalent semiconductors such as graphene, transition metal dichalcogenides, black phosphorus, etc. 2D perovskites are ionic materials, affording many distinct properties of their own, including high photoluminescence quantum efficiency, balanced large exciton binding energy and oscillator strength, and long carrier diffusion length. These unique properties make 2D perovskites potential candidates for optoelectronic and photonic devices such as solar cells, light emitting diodes, photodetectors, nanolasers, waveguides, modulators, and so on, which represent a relatively new but exciting and rapidly expanding area of research. In this Review, the recent advances in emerging 2D metal halide perovskites and their applications in the fields of optoelectronics and photonics are summarized and insights into the future direction of these fields are offered.", "author_names": [ "Xiang Qi", "Yupeng Zhang", "Qingdong Ou", "Son Tung Ha", "C -W Qiu", "Han Zhang", "Yi-Bing Cheng", "Qihua Xiong", "Qiaoliang Bao" ], "corpus_id": 49482257, "doc_id": "49482257", "n_citations": 113, "n_key_citations": 0, "score": 0, "title": "Photonics and Optoelectronics of 2D Metal Halide Perovskites.", "venue": "Small", "year": 2018 }, { "abstract": "Abstract The rediscovery of graphene in the recent past has propelled the rapid development of exfoliation and other thin layer processing techniques, leading to a renewed interest in transition metal dichalcogenides (TMDs) and black phosphorus (BP) in recent years. Since then, TMDs and BP have been extensively studied due to their superior electronic, photonic, and mechanical properties. Like graphene, both TMDs and BP are layered materials with strong in plane bonding and weak out of plane interactions enabling exfoliation into two dimensional (2D) layers of single unit cell thickness. However, the unique intrinsic anisotropic characteristics of BP and sizable bandgaps found in TMDs can be utilized for designing new functional devices, filling the gaps leftover by graphene. This chapter introduces the recent advances made in BP and TMD based electronic and optoelectronics devices. It begins with an overview of their crystal structures and material properties, followed by their methods of synthesis before branching into different applications in electronics and optoelectronics. The section on electronics devices summarizes the recent developments in TMD and BP based electronics, which includes the effect of metal contact, anisotropy, and gate dielectric on field effect transistors based on two dimensional materials (2DMs) new advances in hybrid and monolithic 2D complementary logic circuits, the growth in the demonstration of TMD and BP based memory devices; and lastly, the progress made in 2D printed electronics used in different types of chemical sensors. The current development in TMD and BP based optoelectronics devices is, however, sectioned into two parts. The first part covers optical modulators, semiconductor lasers, and some printed optoelectronics, while the second part reports on photodetectors based on TMD and BP. Device fabrication and techniques used in improving the responsivity, robustness, and response speed of the photodetector are discussed in these two sections as well as the methods that can be used to extend the wavelength detection limit of BP. Finally, the prospects of 2DMs in meeting the International Roadmap for Devices and Systems for the year 2020 and beyond are discussed.", "author_names": [ "Wee Chong Tan", "Xin Chun Huang", "Li Huang", "Lin Wang", "Xuewei Feng", "Li Chen", "Kah-Wee Ang" ], "corpus_id": 214116124, "doc_id": "214116124", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Recent advances in black phosphorus and transition metal dichalcogenide based electronic and optoelectronics devices", "venue": "", "year": 2020 }, { "abstract": "Two dimensional (2D) semiconductors, particularly the direct gap monolayer transition metal dichalcogenides (TMDs) are currently being developed for various atomically thin optoelectronic devices. However, practical applications are hindered by their low quantum efficiencies in light emissions and absorptions. While photonic cavities and metallic plasmonic structures can significantly enhance the light matter interactions in TMDs, the narrow spectral resonance and the local hot spots considerably limit the applications when broadband and large area are required. Here, we demonstrate that a properly designed distributed Bragg reflector (DBR) can be an ideal platform for light coupling enhancement in 2D TMDs. The main idea is based on engineering the amplitude and phase of optical reflection from the DBR to produce optimal substrate induced interference. We show that the photoluminescence, Raman, and second harmonic generation signals of monolayer WSe2 can be enhanced by a factor of 26, 34, and 58, respectively. The proposed DBR substrates pave the way for developing a range of 2D optoelectronic devices for broadband and large area applications.", "author_names": [ "Yen-Chun Chen", "Han Yeh", "Chien-Ju Lee", "Wen-Hao Chang" ], "corpus_id": 13786282, "doc_id": "13786282", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Distributed Bragg Reflectors as Broadband and Large Area Platforms for Light Coupling Enhancement in 2D Transition Metal Dichalcogenides.", "venue": "ACS applied materials interfaces", "year": 2018 }, { "abstract": "It is critically important to characterize the band alignment in semiconductor heterojunctions (HJs) because it controls the electronic and optical properties. However, the well known Anderson's model usually fails to predict the band alignment in bulk HJ systems due to the presence of charge transfer at the interfacial bonding. Atomically thin 2D transition metal dichalcogenide materials have attracted much attention recently since the ultrathin HJs and devices can be easily built and they are promising for future electronics. The vertical HJs based on 2D materials can be constructed via van der Waals stacking regardless of the lattice mismatch between two materials. Despite the defect free characteristics of the junction interface, experimental evidence is still lacking on whether the simple Anderson rule can predict the band alignment of HJs. Here, the validity of Anderson's model is verified for the 2D heterojunction systems and the success of Anderson's model is attributed to the absence of dangling bonds (i.e. interface dipoles) at the van der Waal interface. The results from the work set a foundation allowing the use of powerful Anderson's rule to determine the band alignments of 2D HJs, which is beneficial to future electronic, photonic, and optoelectronic devices.", "author_names": [ "Ming-Hui Chiu", "Wei-Hsuan Tseng", "Hao-Ling Tang", "Yung-Huang Chang", "Chang Hsiao Chen", "Wei-Ting Hsu", "Wen-Hao Chang", "Chih-I Wu", "Lain-Jong Li" ], "corpus_id": 138589020, "doc_id": "138589020", "n_citations": 51, "n_key_citations": 0, "score": 0, "title": "Band Alignment of 2D Transition Metal Dichalcogenide Heterojunctions", "venue": "", "year": 2017 } ]

[ { "abstract": "Wide bandgap semiconductors show superior material properties enabling potential power device operation at higher temperatures, voltages, and switching speeds than current Si technology. As a result, a new generation of power devices is being developed for power converter applications in which traditional Si power devices show limited operation. The use of these new power semiconductor devices will allow both an important improvement in the performance of existing power converters and the development of new power converters, accounting for an increase in the efficiency of the electric energy transformations and a more rational use of the electric energy. At present, SiC and GaN are the more promising semiconductor materials for these new power devices as a consequence of their outstanding properties, commercial availability of starting material, and maturity of their technological processes. This paper presents a review of recent progresses in the development of SiC and GaN based power semiconductor devices together with an overall view of the state of the art of this new device generation.", "author_names": [ "Jose Millan", "Philippe Godignon", "Xavier Perpina", "Amador Perez-Tomas", "Jose Rebollo" ], "corpus_id": 23719999, "doc_id": "23719999", "n_citations": 1075, "n_key_citations": 33, "score": 1, "title": "A Survey of Wide Bandgap Power Semiconductor Devices", "venue": "IEEE Transactions on Power Electronics", "year": 2014 }, { "abstract": "Wide bandgap (WBG) power semiconductor devices have become increasingly popular due to their superior characteristics compared to their Si counterparts. However, their fast switching speed and the ability to operate at high frequencies brought new challenges, among which the electromagnetic interference (EMI) is one of the major concerns. Many works investigated the structures of WBG power devices and their switching performance. In some cases, the conductive or radiated EMI was measured. However, the EMI related topics, including their influence on noise sources, noise propagation paths, EMI reduction techniques, and EMC reliability issues, have not yet been systematically summarized for WBG devices. In this article, the literature on EMI research in power electronics systems with WBG devices is reviewed. Characteristics of WBG devices as EMI noise sources are reviewed. EMI propagation paths, near field coupling, and radiated EMI are surveyed. EMI reduction techniques are categorized and reviewed. Specifically, the EMI related reliability issues are discussed, and solutions and guidelines are presented.", "author_names": [ "Boyi Zhang", "Shuo Wang" ], "corpus_id": 210279101, "doc_id": "210279101", "n_citations": 28, "n_key_citations": 2, "score": 0, "title": "A Survey of EMI Research in Power Electronics Systems With Wide Bandgap Semiconductor Devices", "venue": "IEEE Journal of Emerging and Selected Topics in Power Electronics", "year": 2020 }, { "abstract": "High frequency power converters enabled by wide bandgap (WBG) and silicon semiconductor devices offer distinct advantages in power density and dynamic performance. However, switching oscillations are commonly observed in these circuits with undesirable consequences. This paper reviews the impacts, root causes, and mitigation techniques of switching oscillations through literature survey, modeling analysis, and experimental investigation. We categorize the following root causes for oscillations during switching transients: 1) damped oscillation triggered by high di/dt and/or dv/dt coupled with parasitic elements; 2) undamped oscillation of WBG devices as part of a negative resistance oscillator; and 3) semiconductor device physical mechanisms such as the negative capacitance phenomenon due to conductivity modulation in insulated gate bipolar transistors or impact ionization in MOSFETs, the plasma extraction transit time effect in bipolar power devices, and the reverse conduction property of GaN HEMTs. Furthermore, this paper discusses various circuit techniques to suppress switching oscillations, and techniques of extracting parasitic inductances of power devices.", "author_names": [ "Tianjiao Liu", "Thomas T Y Wong", "Z John Shen" ], "corpus_id": 126982112, "doc_id": "126982112", "n_citations": 21, "n_key_citations": 2, "score": 0, "title": "A Survey on Switching Oscillations in Power Converters", "venue": "IEEE Journal of Emerging and Selected Topics in Power Electronics", "year": 2020 }, { "abstract": "The design considerations for power converters operating at room or at ultra low temperatures are the same in terms of power density, reliability, and efficiency. In order to design power converters at cryogenic temperatures, the passive and active components should be carefully selected. Understanding the behavior of the components at cryogenic temperatures leads to power converter systems that have many superior advantages such as high power density (reduced size and volume) higher efficiency (reduced system losses) and even increased system reliability. This paper reviews the status of the recent research on the cryogenic temperature behavior of Si semiconductor devices, wide bandgap semiconductor devices, passive components, and power converter topologies.", "author_names": [ "Haider Mhiesan", "Md Maksudul Hossain", "Arman Ur Rashid", "Yuqi Wei", "Alan Mantooth" ], "corpus_id": 221280089, "doc_id": "221280089", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Survey of Cryogenic Power Electronics for Hybrid Electric Aircraft Applications", "venue": "2020 IEEE Aerospace Conference", "year": 2020 }, { "abstract": "Since the introduction of wide bandgap (WBG) power semiconductor devices, high power density (PD) inverter design has become an increasingly popular topic in modern research literature. The 2014 2015 Little Box Challenge (LBC) cosponsored by Google and the IEEE sparked even more interest in this area because WBG based designs aspired to achieve upward of 215 W/in³ power densities. This article reviews several key topics of importance that are related to realizing such high PD gallium nitride (GaN) WBG based inverter designs. More specifically, this article includes a comprehensive survey of technologies employed by participating LBC finalists in their efforts to achieve new levels of PD in 400 Vdc to single phase 240 Vac conversion applications while maintaining tight specifications on dc ripple, ac ripple, and aggressive requirements on efficiency. Both singlephase dc to ac conversion and the related active energy buffer circuit topologies used by all LBC finalists are documented and compared. Additionally, a graphical trend line and figure of merit (FOM) are developed that compare PD vis vis efficiency of all proposed solutions. These are used to gain insight into how particular designs were able to achieve relatively higher PD levels and to illustrate how the GaN based design from the University of Illinois at Urbana Champaign (UIUC) was able to achieve the highest density power conversion in this competition. Furthermore, enhanced auxiliary devices and techniques used in the CE+T and Virginia Tech (VT) designs are discussed as well.", "author_names": [ "Clint W Halsted", "Madhav D Manjrekar" ], "corpus_id": 56597613, "doc_id": "56597613", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "A Critique of Little Box Challenge Inverter Designs: Breaking from Traditional Design Tradeoffs", "venue": "IEEE Power Electronics Magazine", "year": 2018 }, { "abstract": "Galvanic isolation between the grid and energy storage unit is typically required for bidirectional power distribution systems. Due to the recent advancement in wide bandgap semiconductor devices, it has become feasible to achieve the galvanic isolation using bidirectional isolated DC/DC converters instead of line frequency transformers. A survey of the latest generation SiC MOSFET is performed. The devices were compared against each other based on their key parameters. It was determined that under the given specifications, the most suitable devices are X3M0016120K 1.2 kV 16 mO and C3M0010090K 900 V 10 mO SiC MOSFETs from Wolfspeed. Two of the most commonly utilized bidirectional isolated DC/DC converter topologies, dual active bridge and CLLC resonant converter are introduced. The operating principle of these converter topologies are explained. A comparative analysis between the two converter topologies, focusing on total device loss, has been performed. It was found that the CLLC converter has lower total device loss compared to the dual active bridge converter under the given specifications. Loss analysis for the isolation transformer in the CLLC resonant converter was also performed at different switching frequencies. It was determined that the total converter loss was lowest at a switching frequency of 250 kHz A prototype for the CLLC resonant converter switching at 250 kHz was then designed and built. Bidirectional power delivery for the converter was verified for power levels up to 25 kW. The converter waveforms and efficiency data were captured at different power levels. Under forward mode operation, a peak efficiency of 98.3% at 15 kW was recorded, along with a full load efficiency value of 98.1% at 25 kW. Under reverse mode operation, a peak efficiency of 98.8% was measured at 17.8 kW. The full load efficiency at 25 kW under reverse mode operation is 98.5% Evaluation and Design of a SiC Based Bidirectional Isolated DC/DC Converter Alex Chu General Audience Abstract Electrical isolation between the grid and energy storage unit is typically required for bidirectional power distribution systems. Traditionally, this isolation is achieved via line frequency transformers, which tend to be bulky and heavy. This imposes a limit on the overall system power density, which is a crucial performance metric for bidirectional power distribution systems. Alternatively, the required electrical isolation can be implemented through bidirectional power converters. As a result, the overall system power density can be drastically improved. However, the losses incurred by the semiconductor devices in such converters could significantly reduce the overall system efficiency, which is another important performance metric. Due to the recent advancement in semiconductor devices, it has become feasible to design the required bidirectional power converters with high efficiency and high power density. A survey of the latest generation semiconductor devices is performed. A 25 kW converter prototype was designed and built using the selected semiconductor devices. Experimental testing was conducted for the converter prototype and efficiency values exceeding 98% were captured across the entire load range. The converter prototype has a power density of 78 W/in.", "author_names": [ "Alex Chu" ], "corpus_id": 115511778, "doc_id": "115511778", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Evaluation and Design of a SiC Based Bidirectional Isolated DC/DC Converter", "venue": "", "year": 2018 }, { "abstract": "At the heart of modern power electronics converters are power semiconductor switching devices. The emergence of wide bandgap (WBG) semiconductor devices, including silicon carbide and gallium nitride, promises power electronics converters with higher efficiency, smaller size, lighter weight, and lower cost than converters using the established siliconbased devices. However, WBG devices pose new challenges for converter design and require more careful characterization, in particular due to their fast switching speed and more stringent need for protection. Characterization of Wide Bandgap Power Semiconductor Devices presents comprehensive methods with examples for the characterization of this important class of power devices. After an introduction, the book covers pulsed static characterization; junction capacitance characterization; fundamentals of dynamic characterization; gate drive for dynamic characterization; layout design and parasitic management; protection design for double pulse test; measurement and data processing for dynamic characterization; cross talk consideration; impact of three phase system; and topology considerations.", "author_names": [ "Fei Wang", "Zheyu Zhang", "Edward A Jones" ], "corpus_id": 139454903, "doc_id": "139454903", "n_citations": 18, "n_key_citations": 3, "score": 0, "title": "Characterization of Wide Bandgap Power Semiconductor Devices", "venue": "", "year": 2018 }, { "abstract": "The emergence of wide bandgap semiconductors has led to development of new generation semiconductor switches that are highly efficient and scalable. To exploit the advantages of GaNFETs in power converters, in terms of reduction in the size of heat sinks and filters, a thorough understanding of the thermal behavior of the device is essential. This paper aims to establish a thermal model for wideband gap semiconductor GaNFETs commercially available, which will enable power electronic designers to obtain the thermal characteristics of the device more effectively. The model parameters is obtained from the manufacturer's data sheet by adopting an exponential curve fitting technique and the thermal model is validated using PSPICE simulations. The model was developed based on the parametric equivalence that exists between the thermal and electrical components, such that it responds for transient thermal stresses. A suitable power profile has been generated to evaluate the GaNFET model under different power dissipation scenarios. The results were compared with a Silicon MOSFETs to further highlight the advantages of the GaN devices. The proposed modeling approach can be extended for other GaN devices and can provide a platform for the thermal study and heat sink optimization.", "author_names": [ "Shri Ram", "Anupa A Vijayakumari" ], "corpus_id": 116344498, "doc_id": "116344498", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Thermal modeling of wide bandgap semiconductor devices for high frequency power converters", "venue": "", "year": 2018 }, { "abstract": "Photovoltaic (PV) energy conversion systems require fast switching power devices that are highly efficient with low semiconductor loss under harsh environmental conditions. Silicon (Si) semiconductor devices are nearing their practical limits in meeting the ever increasing requirements of power converters. However, wide bandgap (WBG) semiconductor devices made from silicon carbide (SiC) are exceeding these limits. SiC power devices enable more efficient and higher performance power converters. This paper presents a non isolated dc dc boost converter based on SiC power devices optimized for use in PV systems. The performance of two otherwise identical converters is compared, one with a new SiC MOSFET/SiC Schottky diode, and one with a conventional Si MOSFET/Si diode. A comparison of switching characteristics and energy loss of each semiconductor device is performed at different switch currents. Converter total loss and overall efficiency are evaluated at different switching frequencies, input voltages, and output power levels. The results indicate that the SiC MOSFET/SiC Schottky diode in the converter is more efficient, performs better, and has reduced power loss compared to the Si MOSFET/Si diode.", "author_names": [ "Saleh S Alharbi", "Ali M S Al-bayati", "Salah S Alharbi", "Mohammad A Matin" ], "corpus_id": 4707429, "doc_id": "4707429", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Performance evaluation of a DC DC boost converter with wide bandgap power devices", "venue": "2017 IEEE Conference on Technologies for Sustainability (SusTech)", "year": 2017 }, { "abstract": "This paper presents a high performance dc dc flyback converter design based on wide bandgap (WBG) semiconductor devices for photovoltaic (PV) applications. Two different power devices, a gallium nitride (GaN) transistor and a silicon (Si) MOSFET, are implemented individually in the flyback converter to examine their impact on converter performance. The total power loss of the converter with different power devices is analyzed for various switching frequencies. Converter efficiency is evaluated at different switching frequencies, input voltages, and output power levels. The results reveal that the converter with the GaN transistor has lower total power loss and better efficiency compared to the converter with the conventional Si MOSFET.", "author_names": [ "Salah S Alharbi", "Saleh S Alharbi", "Ali M S Al-bayati", "Mohammad A Matin" ], "corpus_id": 115341370, "doc_id": "115341370", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design and performance study of a DC DC flyback converter based on wide bandgap power devices for photovoltaic applications", "venue": "Optical Engineering Applications", "year": 2017 } ]

[ { "abstract": "Author(s) Guo, Xinjie Advisor(s) Strukov, Dmitri Abstract: Nervous systems inspired neurocomputing has shown its great advantage in object detection, speech recognition and a lot of other machine learning technology driven applications from speed and power efficiency. Among handful neurocomputing implementation approaches, analog nanoelectronic circuits are very appealing because they may far overcome digital circuits of the same functionality in circuit density, speed and energy efficiency. Device density is one of the most essential metrics for designing large scale neural networks, allowing for high connectivity between neurons. Thanks to the high density nature of traditional memory applications, building artificial neural networks with hybrid complementary metal oxide semiconductor (CMOS)/memory devices would enable the high parallelism as well as achieve the performance advantages.Synapses, the most numerous elements of neural networks, are efficiently implemented by memory devices. This application, however, imposes a number of requirements, such as the continuous change of the memory resistance state, creating the need for novel engineering approaches. Here we report such engineering approaches for advancedcommercial 180 nm ESF1 and 55 nm ESF3 NOR flash memory, facilitating fabrication and successful test of high performance analog vector by matrix multiplication which is the key operation performed at signal propagation through any neuromorphic network. Furthermore, we discuss the recent progress toward neuromorphic computing implementations based on nonvolatile floating gate devices, in particular the experimental results for a prototype 28x28 binary input, 10 output, 3 layer neuromorphic network based on arrays of highly optimized embedded nonvolatile floating gate cells. The fabricated neuromorphic network's active components, including 101,780 floating gate cells, have a total area below 1 mm2. The network has shown a 94.7% classification fidelity on the common MNIST benchmark, close to the 96.2% obtained in simulation. The classification of one pattern takes sub 1 ms time and sub 20 nJ energy both numbers much better than for the best reported digital implementations of the same task. Estimates show that a straightforward optimization of the hardware, and its transfer to the already available 55 nm technology may increase this advantage to more than 100X in speed and 10000X in energy efficiency.As pure analog circuits cannot address the noise accumulation problem, a practical solution would also require inclusion of analog to digital and digital to analog stages for signal restoration. High energy efficient and compact data converters are therefore expected to play an important role in future computing platforms. We perform an experimental demonstration of 6 bit digital to analog (DAC) and 4 bit analog to digital conversion (ADC) operations implemented with a hybrid circuit consisting of Pt/TiO2 x /Pt resistive switching devices (also known as ReRAMs or memristors) and a CMOS operational amplifier (opamp) In particular, ADC is implemented with a Hopfield neural network circuit.", "author_names": [ "Xinjie Guo" ], "corpus_id": 67423264, "doc_id": "67423264", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Mixed Signal Neurocomputing Based on Floating gate Memories", "venue": "", "year": 2017 }, { "abstract": "Potential advantages of analog and mixed signal nanoelectronic circuits, based on floating gate devices with adjustable conductance, for neuromorphic computing had been realized long time ago. However, practical realizations of this approach suffered from using rudimentary floating gate cells of relatively large area. Here, we report a prototype <inline formula> <tex math notation=\"LaTeX\"$28\\times28$ /tex math>/inline formula> binary input, ten output, three layer neuromorphic network based on arrays of highly optimized embedded nonvolatile floating gate cells, redesigned from a commercial 180 nm nor flash memory. All active blocks of the circuit, including 101 780 floating gate cells, have a total area below 1 mm² The network has shown a 94.7% classification fidelity on the common Modified National Institute of Standards and Technology benchmark, close to the 96.2% obtained in simulation. The classification of one pattern takes a sub 1 <inline formula> <tex math notation=\"LaTeX\"\\mu \\text{s} /tex math>/inline formula> time and a sub 20 nJ energy both numbers much better than in the best reported digital implementations of the same task. Estimates show that a straightforward optimization of the hardware and its transfer to the already available 55 nm technology may increase this advantage to more than <inline formula> <tex math notation=\"LaTeX\"$10^{2}\\times /tex math>/inline formula> in speed and <inline formula> <tex math notation=\"LaTeX\"$10^{4}\\times /tex math>/inline formula> in energy efficiency.", "author_names": [ "Farnood Merrikh-Bayat", "Xinjie Guo", "Michael Klachko", "Mirko Prezioso", "Konstantin K Likharev", "Dmitri B Strukov" ], "corpus_id": 51610337, "doc_id": "51610337", "n_citations": 64, "n_key_citations": 1, "score": 0, "title": "High Performance Mixed Signal Neurocomputing With Nanoscale Floating Gate Memory Cell Arrays", "venue": "IEEE Transactions on Neural Networks and Learning Systems", "year": 2018 }, { "abstract": "We have designed, fabricated, and successfully tested a prototype mixed signal, 28x28 binary input, 10 output, 3 layer neuromorphic network \"MLP perceptron\" It is based on embedded nonvolatile floating gate cell arrays redesigned from a commercial 180 nm NOR flash memory. The arrays allow precise ~1% individual tuning of all memory cells, having long term analog level retention and low noise. Each array performs a very fast and energy efficient analog vector by matrix multiplication, which is the bottleneck for signal propagation in most neuromorphic networks. All functional components of the prototype circuit, including 2 synaptic arrays with 101,780 floating gate synaptic cells, 74 analog neurons, and the peripheral circuitry for weight adjustment and I/O operations, have a total area below 1 mm^2. Its testing on the common MNIST benchmark set (at this stage, with a relatively low weight import precision) has shown a classification fidelity of 94.65% close to the 96.2% obtained in simulation. The classification of one pattern takes less than 1 us time and ~20 nJ energy both numbers much better than for digital implementations of the same task. Estimates show that this performance may be further improved using a better neuron design and a more advanced memory technology, leading to a >10^2 advantage in speed and a >10^4 advantage in energy efficiency over the state of the art purely digital (GPU and custom) circuits, at classification of large, complex patterns.", "author_names": [ "Farnood Merrikh-Bayat", "Xinjie Guo", "Michael Klachko", "Mirko Prezioso", "Konstantin K Likharev", "Dmitri B Strukov" ], "corpus_id": 13385056, "doc_id": "13385056", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Sub 1 us, Sub 20 nJ Pattern Classification in a Mixed Signal Circuit Based on Embedded 180 nm Floating Gate Memory Cell Arrays", "venue": "ArXiv", "year": 2016 }, { "abstract": "We present the field programmable array of analog and digital devices (FPAADD) as a novel implementation of a field programmable mixed signal array (FPMA) The FPAADD is a hybrid combination of a field programmable analog array (FPAA) and a field programmable gate array (FPGA) Unlike other FPMAs where the FPGA and FPAA portions are kept separate, this architecture closely integrates the two in a fine grained interleaved array. Instead of using hard coded data converters, the FPAADD synthesizes data converters out of its reconfigurable fabric. The analog and digital portions share a common global interconnect. Floating gate (FG) transistors are used as the switch and memory elements of the chip, providing better switch performance and power over traditional static random access memory based approaches. The precise programmability of the FG switches also allows for computation to take place in the interconnect. These key differences make the FPAADD much more general purpose than previous FPMA architectures. The FPAADD consists of 27 x 8 array of 108 digital and 108 analog tiles and peripheral circuitry on 5 x 5 mm2 die fabricated in a 0.35 mm CMOS process, and contains more than 130 000 FG transistors.", "author_names": [ "Richard B Wunderlich", "Farhan Adil", "Paul E Hasler" ], "corpus_id": 8788832, "doc_id": "8788832", "n_citations": 35, "n_key_citations": 7, "score": 0, "title": "Floating Gate Based Field Programmable Mixed Signal Array", "venue": "IEEE Transactions on Very Large Scale Integration (VLSI) Systems", "year": 2013 }, { "abstract": "The key operation in stochastic neural networks, which have become the state of the art approach for solving problems in machine learning, information theory, and statistics, is a stochastic dot product. While there have been many demonstrations of dot product circuits and, separately, of stochastic neurons, the efficient hardware implementation combining both functionalities is still missing. Here we report compact, fast, energy efficient, and scalable stochastic dot product circuits based on either passively integrated metal oxide memristors or embedded floating gate memories. The circuit's high performance is due to mixed signal implementation, while the efficient stochastic operation is achieved by utilizing circuit's noise, intrinsic and/or extrinsic to the memory cell array. The dynamic scaling of weights, enabled by analog memory devices, allows for efficient realization of different annealing approaches to improve functionality. The proposed approach is experimentally verified for two representative applications, namely by implementing neural network for solving a four node graph partitioning problem, and a Boltzmann machine with 10 input and 8 hidden neurons. Providing efficient and scalable specialized hardware for stochastic neural networks remains a challenge. Here, the authors propose a fast, energy efficient and scalable stochastic dot product circuit that may use either of two types of memory devices metal oxide memristors and floating gate memories.", "author_names": [ "M R Mahmoodi", "Mirko Prezioso", "Dmitri B Strukov" ], "corpus_id": 207941805, "doc_id": "207941805", "n_citations": 28, "n_key_citations": 0, "score": 0, "title": "Versatile stochastic dot product circuits based on nonvolatile memories for high performance neurocomputing and neurooptimization", "venue": "Nature Communications", "year": 2019 }, { "abstract": "We have designed, fabricated, and tested a prototype mixed signal, 28x28 binary input, 10 ouput, 3 layer neuromorphic network based on embedded nonvolatile floating gate cell arrays redesigned from a commercial 180 nm NOR flash memory. Each array performs a very fast and energy efficient analog vector by matrix multiplication, which is the bottleneck for signal propagation in neuromorphic networks. All functional components of the prototype circuit, including 2 synaptic arrays with 101,780 floating gate synaptic cells, 74 analog neurons, and the peripheral circuitry for weight adjustment and I/O operations, have a total area below 1 mm2. Its testing on the MNIST benchmark set has shown a classification fidelity of 94.65% close to the 96.2% obtained in simulation. The classification of one pattern takes <1 ms time and ~20 nJ energy both numbers >103x better than those of the 28 nm IBM TrueNorth digital chip for the same task at a similar fidelity. Estimates show that this performance may be further improved using a better neuron design and a more advanced memory technology, leading to a >102x advantage in speed and a >104x advantage in energy efficiency over the state of the art purely digital circuits for classification of large, complex patterns. Experimental results for the chip to chip statistics, long term drift, and temperature sensitivity show no evident showstoppers on the way toward practical deep neuromorphic networks with unprecedented performance.", "author_names": [ "X Guo", "F Merrikh Bayat", "Mojtaba Bavandpour", "Michael Klachko", "M R Mahmoodi", "Mirko Prezioso", "Konstantin K Likharev", "Dmitri B Strukov" ], "corpus_id": 46098516, "doc_id": "46098516", "n_citations": 102, "n_key_citations": 9, "score": 0, "title": "Fast, energy efficient, robust, and reproducible mixed signal neuromorphic classifier based on embedded NOR flash memory technology", "venue": "2017 IEEE International Electron Devices Meeting (IEDM)", "year": 2017 }, { "abstract": "This work presents a mixed signal physical compu tation electronics for monitoring three vital signs; namely heart rate, blood pressure, and blood oxygen saturation; from electrocardiography, arterial blood pressure, and photoplethysmography signals in real time. The computational circuits are implemented on a reconfigurable and programmable signal processing platform, namely field programmable analog array (FPAA) The design leverages the core enabling technology of FPAA, namely floating gate CMOS devices, and an on chip low power microcontroller to achieve energy efficiency while not compromising accuracy. The custom physical computation electronics operating in CMOS subthreshold region, performs low level (i.e. physiologically relevant feature extraction) and high level (i.e. detecting arrhythmia) signal processing in an energy efficient manner. The on chip microcontroller is used (1) in the programming mode for controlling the charge storage at the analog memory elements to introduce patient dependency into the system and (2) in the run mode to quantify the vital signs. The system has been validated against digital computation results from MATLAB using datasets collected from three healthy subjects and datasets from the MIT/BIH open source database. Based on all recordings in the MIT/BIH database, ECG R peak detection sensitivity is 94.2% The processor detects arrhythmia in three MIT/BIH recordings with an average sensitivity of 96.2% The cardiac processor achieves an average percentage mean error bounded by 3.75% 6.27% and 7.3% for R R duration, systolic blood pressure, and oxygen saturation level calculations; respectively. The power consumption of the ECG, blood pressure and photo plethysmography processing circuitry are 126 nW, 251 nW and 1.44 mW respectively in a 350 nm process. Overall, the cardiac processor consumes 1.82 mW.", "author_names": [ "Sahil S Shah", "Hakan Toreyin", "Cihan Berk Gungor", "Jennifer Olson Hasler" ], "corpus_id": 204968049, "doc_id": "204968049", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "A Real Time Vital Sign Monitoring in the Physical Domain on a Mixed Signal Reconfigurable Platform", "venue": "IEEE Transactions on Biomedical Circuits and Systems", "year": 2019 }, { "abstract": "We have built a 48 tap, mixed signal adaptive FIR filter with 8 bit digital input and an analog output with 10 bits of resolution. The filter stores its tap weights in nonvolatile analog memory cells using synapse transistors, and adapts using the least mean square (LMS) algorithm. We run the input through a digital tapped delay line, multiply the digital words with the analog tap weights using mixed signal multipliers, and adapt the tap coefficients using pulse based feedback. The accuracy of the weight updates exceeds 13 bits. The total die area is 2.6 mm/sup 2/ in a 0.35 /spl mu/m CMOS process. The filter delivers a performance of 19.2 GOPS at 200 MHz, and consumes 20 mW providing a 6 mA differential output current.", "author_names": [ "Miguel Figueroa", "Seth Bridges", "David Hsu", "Chris Diorio" ], "corpus_id": 13225746, "doc_id": "13225746", "n_citations": 22, "n_key_citations": 1, "score": 0, "title": "A 19.2 GOPS mixed signal filter with floating gate adaptation", "venue": "IEEE Journal of Solid State Circuits", "year": 2004 }, { "abstract": "Recently, availability of big data and enormous processing power along with maturing of the applied algorithms, especially for deep learning, have led to a breakthrough in the performance of machine learning algorithms for various applications such as image classification, speech recognition, natural language processing, and so on. The rapidly growing range of machine learning applications, especially in IoT/mobile devices (smart phones, self driving cars, virtual reality gadgets, medical devices, etc. call for a specialized efficient neural processing platform. Of that, there is much more demand for fast, low precision neural inference accelerators than for higher precision systems for network training. Though custom designed digital accelerators significantly outperform their conventional counterparts, their performance is limited due to inherent separation of storage and computing elements and their large footprint. Analog domain in memory computing using nonvolatile memory (NVM) devices appears to be a promising bio inspired solution to break the performance barrier of today's neural accelerators. Small footprint of the storage cells, and their ability to operate as multiplier and accumulators enable compact, fast, and energy efficient implementation of vector by matrix multipliers (VMMs) as the core processing element in the neural accelerators. In this work, we develop several compact, energy efficient time domain VMM approaches based on various NVM devices such as 1T1R resistive cells, 2D NOR floating gate devices, and 3D NAND flash memories. In these approaches, the computation is solely performed via charge transfer while no static power is consumed in the peripheral circuitry. Moreover, the digital nature of the peripheral circuitry in these approaches significantly relaxes the technology node scaling limitation which is a serious challenge for analog domain computing circuits. One of the key advantages of our time domain approach is its full compatibility with complex and compact structure of the commercial 3D NAND memory block enabling the implementation of ultra compact mixed signal neural operators based on this NVM platform. In the second phase of this work, we propose \"aCortex\" an extremely energy efficient, fast, compact, and versatile neuromorphic processor architecture suitable for acceleration of a wide range of neural network inference models. The most important feature of our processor is a configurable mixed signal computing array of vector by matrix multiplier (VMM) blocks utilizing embedded NVM arrays for storing weight matrices. In this architecture, power hungry analog peripheral circuitry for data integration and conversion is shared among a very large array of VMM blocks enabling efficient instant analog/time domain VMM operation for different neural layer types with a wide range of layer specifications. This approach also maximizes the processor's area efficiency through sharing the area hungry high voltage programming switching circuitry as well as the analog peripheries among a large 2D array of NVM blocks. Such compact implementation further boosts the energy efficiency via lowering the digital data transfer cost. Other unique features of aCortex include configurable chain of buffers and data buses, a simple and efficient Instruction Set Architecture (ISA) and its corresponding multi agent controller, and a customized refresh free embedded DRAM memory. Using aCortex estimator, we perform rigorous system level analysis targeting various NVM devices (1T1R ReRAM, and 2D NOR/3D NAND flash) as well as different computing approaches (current/time mode) and propose a roadmap for the future efforts in this domain.", "author_names": [ "Mohammad Bavandpour" ], "corpus_id": 229605946, "doc_id": "229605946", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Toward Efficient Mixed Signal Neural Processors Using Non Volatile Memory Devices", "venue": "", "year": 2020 }, { "abstract": "Test of Integrated Circuits (ICs) is a topic that has been growing in importance in the last decades. Nowadays, about 50% of the total IC cost is related to test. In the past few years, the improvements of microelectronic technology gave the tool to include Analog and Digital structures sharing a unique IC substrate, in what went by the name of Mixed Signal (M S) ICs. The continuous variability of analogue signals and the lack of widely accepted fault models in this domain make analogue and M S Test more demanding and harder than Digital Testing. The analog part of an M S IC uses to take up little IC area but its test is still one of the challenges for microelectronic designers and researchers. On the other hand, Automatic Test Equipments (ATEs) require higher bandwidths than the circuit being tested and demand high speed sampling techniques. In addition, the signal processing is performed off line and requires extensive resources in Analog ATE time and memory, while been reduced the accessibility to some internal parts of the chip. Alternative solutions have been proposed to diminish the AATE cost. Usually the solution comes by moving the test procedure (total or partial) inside the chip. Build In Test (BIT) is a method that weaves most of these problems into a satisfying solution. In this thesis, a BIT approach is proposed, theoretically studied and validated with simulation and experimental results. The proposal is intended to detect parametric and structural faults in the Circuit Under Test (CUT) From the first electronic devices on, Lissajous curves have been used in electronics to test and tune filters and other resources. In this project, human eye has been substituted by an electronic element able to detect changes in the shape of the orthogonal composition of two electronic signals. The proposal is based on an X Y zoning Monitor that uses the CUT's input/Output signals in order to generate a Lissajous composition. The BIT output generates a digital signature which can be internally processed by other embedded structures of the M S circuit or be externally connected to a digital ATE. The thesis includes theoretical studies to model and look for the best configuration of the Analog X Y zoning Monitor. Based on this theory, a first experimental prototype based on programmable analog devices has been developed. Results showed the viability of the method. However, BIT also means minimum IC area, influence of the test on the CUT and other IC related aspects, which need silicon validation. Then, a full custom IC was designed, based on Floating Gate (FG) and Quasi Floating Gate (QFG) transistors, exhaustively simulated and fabricated in a standard CMOS process. Extensive experiments demonstrate that FG and QFG implementations worked as expected, according the extracted simulation results and offer a good compromise area performance. For the CUT&BIT demonstrator cells, Montecarlo simulations have been done to evaluate how process variations affect the CUT&BIT behavior and establish the possible escapes and yield losses. Experimental results, on samples after IC fabrication, show the viability of the integrated Monitor and the X Y zoning approach.", "author_names": [ "Ricard Sanahuja Moliner" ], "corpus_id": 215869200, "doc_id": "215869200", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "On chip monitor for mixed signal testing based on x y zoning", "venue": "", "year": 2006 } ]

[ { "abstract": "We present an analysis of carrier dynamics of the single photon detection process, i.e. from Geiger mode pulse generation to its quenching, in a single photon avalanche diode (SPAD) The device is modeled by a parallel circuit of a SPAD and a capacitance representing both space charge accumulation inside the SPAD and parasitic components. The carrier dynamics inside the SPAD is described by time dependent bipolar coupled continuity equations (BCE) Numerical solutions of BCE show that the entire process completes within a few hundreds of picoseconds. More importantly, we find that the total amount of charges stored on the series capacitance gives rise to a voltage swing of the internal bias of SPAD twice of the excess bias voltage with respect to the breakdown voltage. This, in turn, gives a design methodology to control precisely generated charges and enables one to use SPADs as conventional photodiodes (PDs) in a four transistor pixel of a complementary metal oxide semiconductor (CMOS) image sensor (CIS) with short exposure time and without carrier overflow. Such operation is demonstrated by experiments with a 6 um size 400 x 400 pixels SPAD based CIS designed with this methodology.", "author_names": [ "Akito Inoue", "Toru Okino", "Shinzo Koyama", "Yutaka Hirose" ], "corpus_id": 218983859, "doc_id": "218983859", "n_citations": 3, "n_key_citations": 2, "score": 0, "title": "Modeling and Analysis of Capacitive Relaxation Quenching in a Single Photon Avalanche Diode (SPAD) Applied to a CMOS Image Sensor", "venue": "Sensors", "year": 2020 }, { "abstract": "Exploring the nonlinear photonics of emerging promising two dimensional (2D) materials like MXenes will boost the development of broad band optoelectronic and photonic applications. In this paper, the broad band nonlinear optical response and the excited carrier dynamics of an emerging MXenes, Nb2C, are systematically investigated for the wavelength range of visible to near infrared band. The obtained nonlinear optical response shows a wavelength and excitation intensity dependence. The imaginary part of the third order nonlinear optical susceptibility Imkh(3) and figure of merit (FOM) were found to be 1.4x10 10 esu and 7.5x10 12 esu cm, respectively. The interesting nonlinear absorption response inversion properties (e.g. a shift from saturable absorption to two photon absorption) of Nb2C nanosheets in the near infrared promise possible important applications in nonlinear photonics, such as optical switch. We also demonstrate that the wavelength dependent relaxation times consist of two different relaxation components, i.e. time constants, where one is hundreds of femtoseconds and the other several picoseconds. Our results indicate promising potential in near infrared nanophotonic applications of 2D Nb2C and offer a promising candidate for 2D material based nanophotonic devices and beyond.", "author_names": [ "Yiduo Wang", "Yingwei Wang", "Kun Qi", "Tianyu Xue" ], "corpus_id": 220669770, "doc_id": "220669770", "n_citations": 18, "n_key_citations": 1, "score": 1, "title": "Niobium Carbide Mxenes with Broadband Nonlinear Optic Response and Ultrafast Carrier Dynamics.", "venue": "ACS nano", "year": 2020 }, { "abstract": "Time and angle resolved photoemission spectroscopy (tr ARPES) constitutes a powerful tool to inspect the dynamics and thermalization of hot carriers. The identification of the processes that drive the dynamics, however, is challenging even for the simplest systems owing to the coexistence of several relaxation mechanisms. Here, we devise a Green's function formalism for predicting the tr ARPES spectral function and establish the origin of carrier thermalization entirely from first principles. The predictive power of this approach is demonstrated by an excellent agreement with experiments for graphene over time scales ranging from a few tens of femtoseconds up to several picoseconds. Our work provides compelling evidence of a non equilibrium dynamics dominated by the establishment of a hot phonon regime.", "author_names": [ "Fabio Caruso", "Dino Novko", "Claudia Draxl" ], "corpus_id": 202577628, "doc_id": "202577628", "n_citations": 10, "n_key_citations": 1, "score": 1, "title": "Photoemission signatures of nonequilibrium carrier dynamics from first principles", "venue": "", "year": 2020 }, { "abstract": "Abstract Pump fluence and probe wavelength dependent ultrafast carrier dynamics and optical nonlinear absorption in black phosphorus nanosheets are investigated by transient absorption spectroscopy and open aperture Z scan techniques. The decay time becomes longer with larger wavelengths under pump wavelengths of both 400 nm and 800 nm excitation. For 800 nm excitation, pump fluence dependent lifetime shows complex behaviors, which might be due to the competition between the linear absorption and two photon absorption. For 400 nm excitation, an additional decaying channel is observed at a larger pump fluence, which is explained by an effective subband structure. In open aperture Z scan measurements, strong saturation absorption is observed in the visible region over a broad band from 450 nm to 700 nm. The saturation intensity shows an increasing trend with increase in the wavelength. Also, the saturation intensities under different pulse widths and solvents are discussed in detail. Our results show that black phosphorus nanosheets have great potential in future ultrathin optoelectronic devices.", "author_names": [ "Wenzhi Wu", "Yongjian Zhou", "Jianglong Wang", "Yabin Shao", "Degui Kong", "Yachen Gao", "Yaguo Wang" ], "corpus_id": 216237089, "doc_id": "216237089", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "The pump fluence and wavelength dependent ultrafast carrier dynamics and optical nonlinear absorption in black phosphorus nanosheets", "venue": "", "year": 2020 }, { "abstract": "This chapter presents a review of the current results on the carrier dynamics in activated and self activated scintillators, which are obtained by using time resolved photoluminescence spectroscopy and differential optical absorption techniques with time resolution in picosecond and subpicosecond domains. The optical techniques ensuring a high time resolution are introduced. The formation of the luminescence response to a short pulse excitation is in a special focus. The importance of carrier trapping, peculiarities of the trapping in mixed garnet and orthosilicate type scintillators, and the influence of codoping on excitation transfer are discussed in more detail.", "author_names": [ "Mikhail Korzhik", "Gintautas Tamulaitis", "Andrey N Vasil'ev" ], "corpus_id": 216292088, "doc_id": "216292088", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Free Carrier Dynamics in Scintillation Materials", "venue": "", "year": 2020 }, { "abstract": "We present experimental results on measurement of free carrier dynamics in p type silicon crystal in high electric fields of THz pulses in the MV/cm range. Carrier recombination dynamics in p type silicon is analyzed through time resolved pump probe experiments in which THz pulse is used as a pump, and a femtosecond optical pulse is used as a probe.", "author_names": [ "O V Chefonov", "Andrey V Ovchinnikov", "Mikhail B Agranat" ], "corpus_id": 227128741, "doc_id": "227128741", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Free carrier dynamics in p doped silicon induced by an intense terahertz field", "venue": "Other Conferences", "year": 2020 }, { "abstract": "The influence of doping on the ultrafast carrier dynamics in InSb has been studied by time resolved terahertz spectroscopy with photogenerated carrier densities from 1.5x1018 to 9.5x1019cm 3 at 800 nm. The photoinduced absorption and carrier recovery process show doping type dependence. The carrier recovery time of intrinsic InSb is greater than that of p doped InSb but less than that of n doped InSb at low carrier densities. At high carrier densities, compared with intrinsic InSb, the doped InSb is more prone to transient Auger recombination, which indicates that the appearance of the fast decay process depends on the carrier densities. The photoinduced absorption of terahertz probe pulse of n doped InSb is significantly less than that of p doped and intrinsic InSb; however, that of p doped InSb is close to that of intrinsic InSb, which demonstrates that the high concentration of electrons can accelerate the efficiency of transient Auger recombination. Our analysis provides assistance to the design, manufacture, and improvement of photovoltaic detectors.", "author_names": [ "Gaofang Li", "Xiaobo Nie", "Wei Zhou", "Wenjie Zhang", "Hao Yang Cui", "Nenghong Xia", "Zhiming Huang", "Jun-hao Chu", "Guohong Ma" ], "corpus_id": 228926165, "doc_id": "228926165", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Influence of doping for InSb on ultrafast carrier dynamics measured by time resolved terahertz spectroscopy.", "venue": "Applied optics", "year": 2020 }, { "abstract": "A theoretical study on the coupled electron nuclear dynamics of HD+ molecular ions under ultrashort, intense laser pulses is performed by employing a well established quasi classical model. The influence of the laser carrier envelope phase on various channel (H D+ D H+ and H+ D+ probabilities is investigated at different laser field intensities. The carrier envelope phase is found to govern the dissociation (H D+ and D H+ and Coulomb explosion (H+ D+ channel probabilities. The kinetic energy release distributions of the fragments are also found to be sensitive to the carrier envelope phase of the laser pulse. Our results are in agreement with the previously reported quantum dynamics studies and experiments.", "author_names": [ "Gaurav Pandey", "Diptesh Dey", "Ashwani Kumar Tiwari" ], "corpus_id": 226972993, "doc_id": "226972993", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Controlling the Ultrafast Dynamics of HD+ by the Carrier Envelope Phases of an Ultrashort Laser Pulse: A Quasi Classical Dynamics Study.", "venue": "The journal of physical chemistry. A", "year": 2020 }, { "abstract": "The electronic response of surface deposited nanoparticles to a few cycle near infrared pump pulse is traced by attosecond XUV transient absorption spectroscopy.", "author_names": [ "Florian Lackner", "Julia Anthea Gessner", "Florian Siegrist", "Alexander Schiffmann", "Roman Messner", "Maximilian Lasserus", "Martin Schnedlitz", "Benjamin W Toulson", "Daniel Knez", "Ferdinand Hofer", "Oliver Gessner", "Wolfgang E Ernst", "Martin Schultze" ], "corpus_id": 234523025, "doc_id": "234523025", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Attosecond Spectroscopy of Ultrafast Carrier Dynamics in Nanoparticles", "venue": "", "year": 2020 }, { "abstract": "A type II InAs/AlAs\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin} 69pt} \\begin{document}$_{0.16}\\end{document}0.16Sb\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin} 69pt} \\begin{document}$_{0.84}\\end{document}0.84 multiple quantum well sample is investigated for the photoexcited carrier dynamics as a function of excitation photon energy and lattice temperature. Time resolved measurements are performed using a near infrared pump pulse, with photon energies near to and above the band gap, probed with a terahertz probe pulse. The transient terahertz absorption is characterized by a multi rise, multi decay function that captures long lived decay times and a metastable state for an excess photon energy of \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin} 69pt} \\begin{document}>100$\\end{document}>100 meV. For sufficient excess photon energy, excitation of the metastable state is followed by a transition to the long lived states. Excitation dependence of the long lived states map onto a nearly direct band gap \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin} 69pt} \\begin{document}$E{_g}\\end{document}Eg) density of states with an Urbach tail below \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin} 69pt} \\begin{document}$E{_g}\\end{document}Eg. As temperature increases, the long lived decay times increase \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin} 69pt} \\begin{document}<E{_g}\\end{document}<Eg, due to the increased phonon interaction of the unintentional defect states, and by phonon stabilization of the hot carriers \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin} 69pt} \\begin{document}>E{_g}\\end{document}>Eg. Additionally, Auger (and/or trap assisted Auger) scattering above the onset of the plateau may also contribute to longer hot carrier lifetimes. Meanwhile, the initial decay component shows strong dependence on excitation energy and temperature, reflecting the complicated initial transfer of energy between valence band and defect states, indicating methods to further prolong hot carriers for technological applications.", "author_names": [ "Herath P Piyathilaka", "Rishmali Sooriyagoda", "Hamidreza Esmaielpour", "Vincent R Whiteside", "Tetsuya D Mishima", "Michael B Santos", "Ian R Sellers", "A D Bristow" ], "corpus_id": 232134864, "doc_id": "232134864", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Hot carrier dynamics in InAs/AlAsSb multiple quantum wells", "venue": "Scientific reports", "year": 2021 } ]