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sitloboi2012
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semiconductor_scirepeval_v1

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defect phone glass
[ { "abstract": "Defect detection based on machine vision and machine learning techniques has drawn much attention in recent years. Deep learning is very suitable for such segmentation and detection tasks and has become a promising research area. Surface quality inspection is essentially important in the manufacturing of mobile phone back glass (MPBG) Different types of defects are produced because of the imperfection of the manufacturing technique. Unlike general transparent glass, screen printing glass has totally different reflection and scattering characteristics, which means the traditional dark field imaging system is not suitable for this task. Meanwhile, the imaging system requires high resolution since the minimum defect size can be 0.005 mm2. According to the imaging characteristics of screen printing glass, this paper proposes a coaxial bright field (CBF) imaging system and low angle bright field (LABF) imaging system, and 8K line scan complementary metal oxide semiconductor(CMOS) cameras are utilized to capture images with the resolution size of 16,000*8092. The CBF system is applied for the weak scratch and discoloration defects while the LABF system is applied for the dent defect. A symmetric convolutional neural network composed of encoder and decoder structures is proposed based on U net, which produces a semantic segmentation with the same size as the original input image. More than 10,000 original images were captured, and more than 30,000 defective and non defective images were manually annotated in the glass surface defect dataset (GSDD) Verified by the experiments, the results showed that the average precision reaches more than 91% and the average recall rate reaches more than 95% The method is very suitable for the surface defect inspection of screen printing mobile phone back glass.", "author_names": [ "Jia-Bin Jiang", "Pin Cao", "Zichen Lu", "Weimin Lou", "Yongying Yang" ], "corpus_id": 219776934, "doc_id": "219776934", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Surface Defect Detection for Mobile Phone Back Glass Based on Symmetric Convolutional Neural Network Deep Learning", "venue": "", "year": 2020 }, { "abstract": "In this paper, we propose an unsupervised background reconstruction method to detect defects on surfaces with unevenly distributed textures. An improved deep convolutional autoencoder is utilized to reconstruct the textured background of the original image as a defect free reference. Specifically, a weighted loss function based on structural similarity (SSIM) is utilized to adapt to the unevenly distributed texture background and improve the reconstruction accuracy. Furthermore, combined with the reconstructed defect free reference, a novel difference analysis method based on the discrete cosine transform (DCT) is given to accurately segment the defect regions from the original image. A series of experiments for the defect detection on mobile phone cover glass (MPCG) are conducted. The processing time for an image of 512 x 512 pixels is only 20 ms, which satisfies the requirement of online detection. The experimental results verify the effectiveness of the proposed method.", "author_names": [ "Chengkan Lv", "Zheng-Tao Zhang", "Fei Shen", "Feifei Zhang", "Hu Su" ], "corpus_id": 210232808, "doc_id": "210232808", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "A Fast Surface Defect Detection Method Based on Background Reconstruction", "venue": "International Journal of Precision Engineering and Manufacturing", "year": 2019 }, { "abstract": "Recently, researchers have been studying methods to introduce deep learning into automated optical inspection (AOI) systems to reduce labor costs. However, the integration of deep learning in the industry may encounter major challenges such as sample imbalance (defective products that only account for a small proportion) Therefore, in this study, an anomaly detection neural network, dual auto encoder generative adversarial network (DAGAN) was developed to solve the problem of sample imbalance. With skip connection and dual auto encoder architecture, the proposed method exhibited excellent image reconstruction ability and training stability. Three datasets, namely public industrial detection training set, MVTec AD, with mobile phone screen glass and wood defect detection datasets, were used to verify the inspection ability of DAGAN. In addition, training with a limited amount of data was proposed to verify its detection ability. The results demonstrated that the areas under the curve (AUCs) of DAGAN were better than previous generative adversarial network based anomaly detection models in 13 out of 17 categories in these datasets, especially in categories with high variability or noise. The maximum AUC improvement was 0.250 (toothbrush) Moreover, the proposed method exhibited better detection ability than the U Net auto encoder, which indicates the function of discriminator in this application. Furthermore, the proposed method had a high level of AUCs when using only a small amount of training data. DAGAN can significantly reduce the time and cost of collecting and labeling data when it is applied to industrial detection.", "author_names": [ "Tang Tang", "Wei-Han Kuo", "Jauh-Hsiang Lan", "Chien-Fang Ding", "Hakiem Hsu", "Hong-Tsu Young" ], "corpus_id": 219726774, "doc_id": "219726774", "n_citations": 11, "n_key_citations": 0, "score": 1, "title": "Anomaly Detection Neural Network with Dual Auto Encoders GAN and Its Industrial Inspection Applications", "venue": "Sensors", "year": 2020 }, { "abstract": "Abstract Ultra thin curved (2.5D, 3D) glass is widely used in the most recently developed smartphones, and the market demand for it is steadily increasing. The high precision ultra thin glass molding process (UTGMP) is very important in the fabrication of high quality 2.5D/3D ultra thin glass for smartphones; however, the UTGMP, with its high energy consumption and low pass rate, is not considered to be environment friendly. Therefore, in this study, the sustainability of the molding process for 3D ultra thin glass was comprehensively investigated. First, the ultra thin 3D glass molding process is described, including a discussion of the glass molding apparatus, and the principle of glass thermos formation is explained. Secondly, a thermo mechanical coupling model is proposed to study the effects of loading heat and pressure on the distributions of temperature and internal stress of ultra thin glass. The results demonstrate that significant amounts of stress were concentrated at the edges, and in holes and slots. A series of experiments were conducted to reveal the respective effect of various UTGMP parameters on the energy consumption, pass rate, and carbon emission level of the process. Consequently, the percentage of the main effect of loading temperature on energy consumption was found to be 23.65% whereas that of the duration of applied pressure on the pass rate was determined to be 52.48% The optimal process parameter combinations were determined by analyzing the above mentioned research results and subsequently implementing them in a hybrid intelligent optimization algorithm that utilizes quantum behaved particle swarm optimization (QPSO) and a back propagation neural network (BPNN) The algorithm revealed that energy consumption and carbon emissions can be respectively decreased by 3.39% and 3.45% at a relatively high pass rate (i.e. over 70% Eventually, the suggested combinations for the UTGMP will be able to achieve at least 60% 76% of the pass rate, as well as consume no more than 0.756 kW h/pcs to meet sustainable manufacturing requirements. Thus, this study contributes to the effective application of a high precision glass molding process for the sustainable manufacturing of ultra thin curved glass.", "author_names": [ "Zhen Bin Zhang", "Wuyi Ming", "Yi Zhang", "Ling Yin", "Tao Xue", "Zhijun Chen", "Dunming Liao", "Guojun Zhang" ], "corpus_id": 213469658, "doc_id": "213469658", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Analyzing sustainable performance on high precision molding process of 3D ultra thin glass for smart phone", "venue": "", "year": 2020 }, { "abstract": "Glass bottles must be thoroughly inspected before they are used for packaging. However, the vision inspection of bottle bottoms for defects remains a challenging task in quality control due to inaccurate localization, the difficulty in detecting defects in the texture region, and the intrinsically nonuniform brightness across the central panel. To overcome these problems, we propose a surface defect detection framework, which is composed of three main parts. First, a new localization method named entropy rate superpixel circle detection (ERSCD) which combines least squares circle detection and entropy rate superpixel (ERS) with an improved randomized circle detection, is proposed to accurately obtain the region of interest (ROI) of the bottle bottom. Then, according to the structure property, the ROI is divided into two measurement regions: central panel region and annular texture region. For the former, a defect detection method named frequency tuned anisotropic diffusion super pixel segmentation (FTADSP) that integrates frequency tuned salient region detection (FT) anisotropic diffusion, and an improved superpixel segmentation is proposed to precisely detect the regions and boundaries of defects. For the latter, a defect detection strategy called wavelet transform multiscale filtering (WTMF) based on a wavelet transform and a multiscale filtering algorithm is proposed to reduce the influence of texture and to improve the robustness to localization error. The proposed framework is tested on four data sets obtained by our designed vision system. The experimental results demonstrate that our framework achieves the best performance compared with many traditional methods.", "author_names": [ "Xianen Zhou", "Yaonan Wang", "Qing Zhu", "Jianxu Mao", "Changyan Xiao", "Xiao Lu", "Huixia Zhang" ], "corpus_id": 201890408, "doc_id": "201890408", "n_citations": 18, "n_key_citations": 0, "score": 1, "title": "A Surface Defect Detection Framework for Glass Bottle Bottom Using Visual Attention Model and Wavelet Transform", "venue": "IEEE Transactions on Industrial Informatics", "year": 2020 }, { "abstract": "Most of previous works studied the bioactivity of tertiary soda lime borate as in vitro method, but, there have been no previous studies investigated the in vivo compatibility of such glass. This work was mainly aimed at in vivo assessment of bone formation of tertiary soda lime borate bioactive glass doped with Sr. the glass composition was based on 60 B 2 O 3 20 Na 2 O (20 x CaO x SrO (wt% where, x 0 and 10 wt% (samples encoded B0 and BS, respectively) The in vivo test was conducted in femoral bone defect of Sprague Dawley adult male rats after 3 and 6 weeks post surgery using the histological analyses and bone formation markers (alkaline phosphatase (ALP) and osteocalcin (OCN) Moreover, the possible systemic toxicity was studied using different biochemical analyses (alanine transaminase, aspartate transaminase, urea and creatinine) The result of bone markers showed that serum OCN level increased in rat implanted with sample B0 than that observed in sample BS at 3 and 6 weeks post implantation, while this finding was reversed in ALP activity. In vivo bioactivity test showed that implantation of all borate glasses did not demonstrate local or general complications in all rats, and they exhibited nearly complete bone mineralization. However, BS glass was formed more new bone than B0 one in long implantation time. In conclusion, the synthesized bioactive borate glasses were safe materials, and introducing of Sr in the glass was enhanced formation of new bone throughout long time of implantation. Accordingly, this glass can be used as a potential substitute for bone regenerative materials and a hosting for strontium ions delivery.", "author_names": [ "Zainab M Al-Rashidy", "Areg E Omar", "Tamer H Abd El-Aziz", "Mohammad M Farag" ], "corpus_id": 218528037, "doc_id": "218528037", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "In vivo bioactivity assessment of strontium containing soda lime borate glass implanted in femoral defect of rat", "venue": "Journal of Inorganic and Organometallic Polymers and Materials", "year": 2020 }, { "abstract": "Abstract Currently, the shear pre tension coupling behavior and evolution of various mesoscopic defects for the biaxial non crimp fabric (NCF) are not revealed. Here, this work systematically conducted the picture frame shear with applied pre tension and hemisphere forming for the 45deg and 0/90deg glass NCF. In the picture frame shearing, it is identified that the effective shear response of the biaxial NCF in the positive shear mode should be characterized in the cycle 1 due to the irreversible destruction of the NCF architecture. Besides, the applying pre tension is originally demonstrated to be capable of effectively suppressing the wrinkle defect and delaying the triggering shear angle of the wrinkle. Moreover, for the 45deg NCF, the stitching thread suffers tension in positive shear mode, and the wrinkle is the main defect. In the negative shear mode, due to the non pure shearing at high shear angle and compression of stitching thread, the mesoscopic defects, including bending and unit cell buckling of the stitching thread, are generated. In the hemisphere forming, it is revealed that the shear deformation is certainly arose in the tensile region of the 45deg NCF due to the asymmetrical yarn shrink. The same fabric wrinkle and mesoscopic stitching thread defects are also originally identified, demonstrating the hemisphere forming is highly correlated to the large shear deformation. The results here provide a basic reference to suppress the defects in the performing process of the biaxial NCF.", "author_names": [ "Ming Mei", "Yujia He", "Xujing Yang", "Kai Wei", "Zhaoliang Qu", "Daining Fang" ], "corpus_id": 216502804, "doc_id": "216502804", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Shear deformation characteristics and defect evolution of the biaxial 45deg and 0/90deg glass non crimp fabrics", "venue": "", "year": 2020 }, { "abstract": "The use of bone scaffolds to replace injured or diseased bone has many advantages over the currently used autologous and allogeneic options in clinical practice. This systematic review evaluates the current evidence for non cellular scaffolds containing bioactive glass on osteogenesis and angiogenesis in animal bone defect models. Studies that reported results of osteogenesis via micro CT and results of angiogenesis via Microfil perfusion or immunohistochemistry were included in the review. A literature search of PubMed, EMBASE and Scopus was carried out in November 2019 from which nine studies met the inclusion and exclusion criteria. Despite the significant heterogeneity in the composition of the scaffolds used in each study, it could be concluded that scaffolds containing bioactive glass improve bone regeneration in these models, both by osteogenic and angiogenic measures. Incorporation of additional elements into the glass network, using additives, and using biochemical factors generally had a beneficial effect. Comparing the different compositions of non cellular bioactive glass containing scaffolds is however difficult due to the heterogeneity in bioactive glass compositions, fabrication methods and biochemical additives used.", "author_names": [ "Chanuka D S Ranmuthu", "Charindu K I Ranmuthu", "Disha Singhania" ], "corpus_id": 218616617, "doc_id": "218616617", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Evaluating the Effect of Non cellular Bioactive Glass Containing Scaffolds on Osteogenesis and Angiogenesis in in vivo Animal Bone Defect Models", "venue": "Frontiers in Bioengineering and Biotechnology", "year": 2020 }, { "abstract": "Abstract Demands for display panels and relevant technologies are rapidly increasing with the recent advances in smart mobile devices. Many manufacturers have begun slowly investing in fully automated inspection systems that enable consistent and objective inspections. Carrying out such undertaking aims to satisfy high user requirements concerning quality while coping with high volumes. Cover glass is one of the important items for inspection because users directly interact with it. Despite the extensive use of typical machine vision based solutions in this field, many manufacturers continue relying on human based judgment because of a deficient understanding of defects or poor confidence in algorithms. To overcome these problems, this study proposes a deep learning neural network (DLNN) based defect inspection system. The DLNN has advantages over traditional computer vision or human based inspection in terms of flexibility and performance. We introduce a weighted multi DLNN inspection system capable of efficiently utilizing multi channel measurement data, with a detection rate of up to 99% and a false pass rate below 1%", "author_names": [ "Jisu Park", "Hamza Riaz", "Hyunchul Kim", "Jungsuk Kim" ], "corpus_id": 213469045, "doc_id": "213469045", "n_citations": 5, "n_key_citations": 0, "score": 1, "title": "Advanced cover glass defect detection and classification based on multi DNN model", "venue": "", "year": 2020 }, { "abstract": "Abstract The effect of cerium content on phase evolution, dielectric properties and defect mechanism has been investigated in (Ba,Sr)TiO3 glass ceramics. Cerium mainly acts as an isovalent dopant in the B site of ABO3 perovskite structure at low content (1 mol% and then cerium substitution gradually occurs in the A site with increasing cerium content. A compensation mechanism related to variation in oxygen vacancy concentration has been identified. When cerium content increased to 2 mol% the maximum values of dielectric constant and energy storage density were simultaneously achieved. The impedance spectra revealed the highest conductivity. It was due to the increase in the concentration of charge carriers accompanied by the decrease in the activation energy of oxygen vacancy migration. With a further addition of cerium to 3 mol% the opposite trend was observed. The result is related to the presence of more cation vacancies, which, in turn, limits the diffusion rate of oxygen vacancy.", "author_names": [ "Zhangyuan Zhao", "Xuewei Liang", "Tianyuan Zhang", "Kangjia Hu", "Shenhou Li", "Yue-fei Zhang" ], "corpus_id": 210804231, "doc_id": "210804231", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Effects of cerium doping on dielectric properties and defect mechanism of barium strontium titanate glass ceramics", "venue": "", "year": 2020 } ]
amorphous polycrystalline solar panel spectral response
[ { "abstract": "Quantum dot solar cells are based on the concept of harvesting different parts of the solar light spectrum with a single, cheap semiconductor by simply changing the size of the nanoparticles. Of th.", "author_names": [ "Jacopo Parravicini", "Francesco Di Trapani", "Michael D Nelson", "Zachary T Rex", "Ryan Beiter", "Tiziano Catelani", "Maurizio Acciarri", "Alessandro Podesta", "Cristina Lenardi", "Simona Binetti", "Marcel Di Vece" ], "corpus_id": 214065245, "doc_id": "214065245", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Quantum Confinement in the Spectral Response of n Doped Germanium Quantum Dots Embedded in an Amorphous Si Layer for Quantum Dot Based Solar Cells", "venue": "", "year": 2020 }, { "abstract": "Spectral response and diffusion length characteristics of the various MIS cells developed at Rutgers and previously reported in the literature have been investigated. The cells, designated according to the type of Si substrate used, appear in the following descending order based on the above studies: (1) Monsanto single crystal Si with a peak quantum efficiency (QE) of 87.4% and a diffusion length (Ln) of 70 mm, (2) Wacker polycrystalline Si, peak QE=82.8% Ln=60 mm, (3) IBM ribbon Si, (4) epitaxial Si, (5) Mobil Tyco EFG ribbon Si, and (6) amorphous Si (Plasma Physics Corp. Theoretical plots of quantum efficiency and short circuit current density are shown to be in reasonable agreement with experimental results. The enhanced ultraviolet response of the MIS cell compared to that of a commercial N/P junction cell is demonstrated even though the latter device has a peak QE of almost 100% and an Ln value of 184 mm. The spectral studies lend support to the conclusions derived from the previously measured el.", "author_names": [ "Sandwip K Dey", "William A Anderson", "Alan E Delahoy", "Christophe Cartier" ], "corpus_id": 121749374, "doc_id": "121749374", "n_citations": 9, "n_key_citations": 0, "score": 1, "title": "Spectral response and diffusion length studies of amorphous, polycrystalline, ribbon, epitaxial, and single crystal silicon MIS solar cells", "venue": "", "year": 1979 }, { "abstract": "Reactive ion etching technology was combined with passivated emitter rear cell technology to reduce the reflectance and transmittance of incident light and improve the spectral response of polycrystalline silicon solar cell. Preconditioning with acid solution can induce the formation of worm like structures on the front surface, which could bring about the reduction of reflectance and enhancement of spectral response in the visible range. Optimization of the capping layer thickness on the rear side can enhance the internal reflection, which will decrease the transmittance and promote the spectral response in long wavelength range.", "author_names": [ "Shude Zhang", "Hongqiang Qian", "Jiaqi Peng", "Qingzhu Wei", "Zhichun Ni" ], "corpus_id": 54444337, "doc_id": "54444337", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Spectral Response Optimization of Polycrystalline Black Silicon Solar Cell by Reactive Ion Etching Combined with PERC Technology", "venue": "2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC 34th EU PVSEC)", "year": 2018 }, { "abstract": "The heterojunction silicon solar cells displaying two different open circuit voltages and having S shape light current density voltage characteristics are analyzed by observing change in quantum efficiency (QE) with voltage and light bias conditions. With forward bias voltage close to (and beyond) the S shape region, the QE is reduced uniformly in all the regions, due to dominance of barrier over junction field for collection of holes. Under white light bias along with the voltage biasing close to the S shape characteristics, an improvement of QE is observed due to saturation of defects at the interface and enhancement of photoconductivity of the amorphous Si layers. The cell with small open circuit voltage showed considerable improvement in QE from interfacial region (e.g. in the short and long wavelength region) while response in the bulk region (intermediate wavelength region) remains flat.", "author_names": [ "Sapna Mudgal", "Son Pal Singh", "Vamsi Krishna Komarala" ], "corpus_id": 54214415, "doc_id": "54214415", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Interfacial spectral response under voltage and light bias to analyse low voltage in amorphous crystalline silicon heterojunction solar cell with S shape characteristics", "venue": "2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC 34th EU PVSEC)", "year": 2018 }, { "abstract": "Spectral response and diffusion length characteristics of the various MIS cells developed at Rutgers and previously reported in the literature have been investigated. The cells, designated according to the type of Si substrate used, appear in the following descending order based on the above studies: (1) Monsanto single crystal Si with a peak quantum efficiency (Q.E. of 87.4% and a diffusion length (Ln) of 70 um, (2) Wacker polycrystalline Si, peak Q.E. 82.8% Ln= 60 um, (3) IBM ribbon Si, (4) Epitaxial Si, (5) Mobil Tyco EFG ribbon Si and (6) amorphous Si. The Q.E. of the Monsanto Si base line cell is shown to be adequately explained in terms of the wavelength dependence of the collection efficiency and the transmittance of the barrier metal. Good agreement is also shown between theoretical and experimental plots of short circuit current density (Jsc) versus Ln. The Wacker cell shows best short wavelength response of all the cells studied including a commercial p n cell having a peak Q.E. of 100% and Ln= 184 um.", "author_names": [ "Sandwip K Dey", "William A Anderson", "Alan E Delahoy", "Christophe Cartier" ], "corpus_id": 22229, "doc_id": "22229", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Relating photovoltaic output and spectral response of amorphous, polycrystalline, ribbon, epitaxial and single crystal MIS solar cells", "venue": "1978 International Electron Devices Meeting", "year": 1978 }, { "abstract": "The seasonal variations of solar photovoltaic cells photocurrent under cloudless conditions are analyzed. This analysis is done by using models of the absorption of solar radiation in the atmosphere and the spectral response of various types of solar cells. The problems of determining the atmospheric model parameters for calculating seasonal variations in absorption are indicated. A simple model that describes the effects of degradation and regeneration of photosensitive material is proposed to describe peculiarities of seasonal variations in the photocurrent of amorphous silicon cells.", "author_names": [ "A L Bozhenko", "Yuri Y Dymytrov", "Vladimir I Kubov", "R M Kubova" ], "corpus_id": 218563902, "doc_id": "218563902", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "The Photovoltaic Cells Spectral Response and Photocurrent Seasonal Variations", "venue": "2020 IEEE 40th International Conference on Electronics and Nanotechnology (ELNANO)", "year": 2020 }, { "abstract": "Abstract In this paper, high temperature solar blind photodetectors were fabricated based on polycrystalline Ga2O3 (poly Ga2O3) film which was prepared by annealing amorphous Ga2O3 (a Ga2O3) film in oxygen atmosphere. The effects of annealing temperature on the properties of the material and the performances of the corresponding Metal semiconductor metal photodetector were investigated. The main factors affecting device performance are attributed to the oxygen vacancy defect concentration in Ga2O3 and the effective Schottky barrier height and width between gold and Ga2O3. We found that the detector based on 650 degC annealed poly Ga2O3 showed the best solar blind detection photoelectric performance and good thermal stability. More interestingly, the device has fast response recovery speed (0.16 s) low dark current =0.1 nA) and high photo to dark current ratio =97) at 200 degC high temperature operation. These performances are even better than the reported high temperature photodetectors based on high quality crystal Ga2O3 thin film or Ga2O3 bulk. Besides, our method that avoid direct high temperature growth of poly Ga2O3 and may be beneficial to its commercial large area production and further cost reduction.", "author_names": [ "Hai-tao Zhou", "Lujia Cong", "Jiangang Ma", "Ming-Zhu Chen", "Dongyu Song", "Hong-bin Wang", "Peng Li", "Bingsheng Li", "Haiyang Xu", "Yi-chun Liu" ], "corpus_id": 225154731, "doc_id": "225154731", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "High performance high temperature solar blind photodetector based on polycrystalline Ga2O3 film", "venue": "", "year": 2020 }, { "abstract": "Abstract An important requirement for a very fast spectral response measurement system is the simultaneous illumination of the solar cell at multiple well defined wavelengths. Nowadays this can be done by means of light emitting diodes (LEDs) available for a multitude of wavelengths. For the purpose to measure the spectral response (SR) of amorphous silicon solar cells a detailed characterization of LEDs emitting in the wavelength range from 300 nm to 800 nm was performed. In the here developed equipment the LED illumination is modulated in the frequency range from 100 Hz to 200 Hz and the current generated by each LED is analyzed by a Fast Fourier Transform (FFT) to determine the current component corresponding to each wavelength. The equipment provides a signal to noise ratio of 2 4 orders of magnitude for individual wavelengths resulting in a precise measurement of the SR over the whole wavelength range. The difference of the short circuit current determined from the SR is less than 1% in comparison to a conventional system with monochromator.", "author_names": [ "J A Rodriguez", "Montserrat Fortes", "Cesar Alberte", "Michael Vetter", "Jordi S Andreu" ], "corpus_id": 97471514, "doc_id": "97471514", "n_citations": 16, "n_key_citations": 1, "score": 0, "title": "Development of a very fast spectral response measurement system for analysis of hydrogenated amorphous silicon solar cells and modules", "venue": "", "year": 2013 }, { "abstract": "Solar blind photodetectors are critically important for civil and military applications. Several of these applications, such as space exploration and nuclear energy infrastructure, demand the use of a photodetector under extreme environments. In this paper, we have studied the radiation hardness and device performance of amorphous and polycrystalline gallium oxide thin films against heavy ion (Ag7+ irradiation with a high energy of 100 MeV. Gallium oxide thin films show great tenacity against massive and highly energetic ions. The amorphous and polycrystalline phases undergo structural and morphological changes that initially induce degradation in the device performance. Nano pore like structures are formed in the amorphous film, while the polycrystalline film shows the destruction of large crystallites. The responsivity of the photodetector device reduces fourfold in the amorphous phase; however, a sixfold reduction in the performance is observed in the polycrystalline phase of the gallium oxide photodetector. The degradation is attributed to the annealing of pre existing optical defects that are otherwise responsible for the huge photoconductive gain in the detector and confirmed by photoluminescence studies. The effect of self annealing at room temperature and annealing at moderate temperature is investigated to recover the irradiated photodetector devices. Partial recovery in the polycrystalline based photodetector and two orders of magnitude enhanced responsivity and an almost twice faster response time compared to the control photodetectors in the amorphous phase are observed. This work investigates the effect of heavy and energetic ions on the performance of gallium oxide based solar blind photodetector and provides the guideline to use high energy irradiation as a tool for defect engineering.", "author_names": [ "Damanpreet Kaur", "Pargam Vashishtha", "Saif A Khan", "Pawan Kumar Kulriya", "Govind Gupta", "Mukesh Kumar" ], "corpus_id": 225493587, "doc_id": "225493587", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Phase dependent radiation hardness and performance analysis of amorphous and polycrystalline Ga2O3 solar blind photodetector against swift heavy ion irradiation", "venue": "", "year": 2020 }, { "abstract": "Abstract We employed the low temperature hydrogenated amorphous silicon nitride (a SiN x :H) prepared by plasma enhanced chemical vapor deposition as a refractive index n matching layers in a silicon based thin film solar cell between glass n 1.5) and the transparent conducting oxide n 2) By varying the stoichiometry, refractive index and thickness of the a SiN x :H layers, we enhanced the spectral response and efficiency of the hydrogenated amorphous silicon thin film solar cells. The refractive index of a SiN x :H was reduced from 2.32 to 1.78. Optimizing the a SiN x :H thickness to 80 nm increased the J SC from 8.3 to 9.8 mA/cm 2 and the corresponding cell efficiency increased from 4.5 to 5.3% as compared to the cell without the a SiN x :H index matching layer on planar substrate. The a SiN x :H layers with graded refractive indices were effective for enhancing the cell performance.", "author_names": [ "Ching-Yi Hsu", "Y P Lin", "Hung-Jung Hsu", "Chin-Chung Tsai" ], "corpus_id": 56156245, "doc_id": "56156245", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Enhanced spectral response by silicon nitride index matching layer in amorphous silicon thin film solar cells", "venue": "", "year": 2012 } ]
WAFER classification
[ { "abstract": "Silicon wafer is the most crucial material in the semiconductor manufacturing industry. Owing to limited resources, the reclamation of monitor and dummy wafers for reuse can dramatically lower the cost, and become a competitive edge in this industry. However, defects such as void, scratches, particles, and contamination are found on the surfaces of the reclaimed wafers. Most of the reclaimed wafers with the asymmetric distribution of the defects, known as the \"good (G)\" reclaimed wafers, can be re polished if their defects are not irreversible and if their thicknesses are sufficient for re polishing. Currently, the \"no good (NG)\" reclaimed wafers must be first screened by experienced human inspectors to determine their re usability through defect mapping. This screening task is tedious, time consuming, and unreliable. This study presents a deep learning based reclaimed wafers defect classification approach. Three neural networks, multilayer perceptron (MLP) convolutional neural network (CNN) and Residual Network (ResNet) are adopted and compared for classification. These networks analyze the pattern of defect mapping and determine not only the reclaimed wafers are suitable for re polishing but also where the defect categories belong. The open source TensorFlow library was used to train the MLP, CNN, and ResNet networks using collected wafer images as input data. Based on the experimental results, we found that the system applying CNN networks with a proper design of kernels and structures gave fast and superior performance in identifying defective wafers owing to its deep learning capability, and the ResNet averagely exhibited excellent accuracy, while the large scale MLP networks also acquired good results with proper network structures.", "author_names": [ "Po-Chou Shih", "Chun-Chin Hsu", "F C Tien" ], "corpus_id": 219071734, "doc_id": "219071734", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Automatic Reclaimed Wafer Classification Using Deep Learning Neural Networks", "venue": "Symmetry", "year": 2020 }, { "abstract": "", "author_names": [ "Hyun-Jin Kim", "Kwan-Young Bak", "Jae-Kyung Shin", "Ja-Yong Koo" ], "corpus_id": 216168421, "doc_id": "216168421", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Functional Logistic Regression based on Constant Splines for Wafer Classification", "venue": "", "year": 2020 }, { "abstract": "A wafer bin map (WBM) which is the result of an electrical die sorting test, provides information on which bins failed what tests, and plays an important role in finding defective wafer patterns in semiconductor manufacturing. Current wafer inspection based on WBM has two problems: good/bad WBM classification is performed by engineers and the bin code coloring scheme does not reflect the relationship between bin codes. To solve these problems, we propose a neural network based bin coloring method called Bin2Vec to make similar bin codes are represented by similar colors. We also build a convolutional neural network based WBM classification model to reduce the variations in the decisions made by engineers with different expertise by learning the company wide historical WBM classification results. Based on a real dataset with a total of 27,701 WBMs, our WBM classification model significantly outperformed benchmarked machine learning models. In addition, the visualization results of the proposed Bin2Vec method makes it easier to discover meaningful WBM patterns compared with the random RGB coloring scheme. We expect the proposed framework to improve both efficiencies by automating the bad wafer classification process and effectiveness by assigning similar bin codes and their corresponding colors on the WBM.", "author_names": [ "Junhong Kim", "Hyungseok Kim", "Jaesun Park", "Kyounghyun Mo", "Pilsung Kang" ], "corpus_id": 116259654, "doc_id": "116259654", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Bin2Vec: A Better Wafer Bin Map Coloring Scheme for Comprehensible Visualization and Effective Bad Wafer Classification", "venue": "Applied Sciences", "year": 2019 }, { "abstract": "In the semiconductor manufacturing process, it is important to identify wafers on which faults have occurred or will occur to avoid unnecessary and costly further processing and physical inspections. This issue can be addressed by formulating the faulty wafer detection problem as a predictive modeling task, in which the process parameters/measurements and subsequent inspection results concerning the faults comprise the input and output variables at the wafer level, respectively. To achieve improved predictive performance, this paper presents a joint modeling method that incorporates classification and regression tasks into a single prediction model. Given the output variables in both binary and continuous forms, the prediction model simultaneously considers both the classification and regression tasks to complement each other, where each task predicts the binary and continuous output variables, respectively. The outputs from these two tasks are combined to predict whether a wafer is faulty. The entire model is implemented as a neural network, and is trained by optimizing a single objective function. The effectiveness of the model is demonstrated with a case study using real world data from a semiconductor manufacturer.", "author_names": [ "Seokho Kang" ], "corpus_id": 115997705, "doc_id": "115997705", "n_citations": 11, "n_key_citations": 1, "score": 0, "title": "Joint modeling of classification and regression for improving faulty wafer detection in semiconductor manufacturing", "venue": "J. Intell. Manuf.", "year": 2020 }, { "abstract": "Wafer map analysis provides critical information for quality control and yield improvement tasks in semiconductor manufacturing. In particular, wafer patterns of gross failing areas (GFA) are important clues to identify the causes of relevant failures during the manufacturing process. In this work, a semi supervised classification framework is proposed for wafer map analysis, and its application to wafer bin maps with GFA patterns classification is demonstrated. The Ladder network and the semi supervised variational autoencoder are adopted to classify wafer bin maps in comparison with a standard convolutional neural network (CNN) model on two real world datasets. The results have illustrated that two semi supervised models are consistently and substantially better than the CNN model across various training data percentages by effective utilization of the unlabeled data. Active learning and pseudo labeling are also utilized to accelerate the learning curve.", "author_names": [ "Yuting Kong", "Dong Ni" ], "corpus_id": 211055625, "doc_id": "211055625", "n_citations": 9, "n_key_citations": 1, "score": 1, "title": "A Semi Supervised and Incremental Modeling Framework for Wafer Map Classification", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2020 }, { "abstract": "Defect clusters on the wafer map can provide important clue to identify the process failures so that it is important to accurately classify the defect patterns into corresponding pattern types. In this research, we present an image based wafer map defect pattern classification method. The presented method consists of two main steps: without any specific preprocessing, high level features are extracted from convolutional neural network and then the extracted features are fed to combination of error correcting output codes and support vector machines for wafer map defect pattern classification. To the best of our knowledge, no prior work has applied the presented method for wafer map defect pattern classification. Experimental results tested on 20,000 wafer maps show the superiority of presented method and the overall classification accuracy is up to 98.43%", "author_names": [ "Cheng Hao Jin", "Hyun-Jin Kim", "Yongjun Piao", "Meijing Li", "Minghao Piao" ], "corpus_id": 213671935, "doc_id": "213671935", "n_citations": 9, "n_key_citations": 1, "score": 0, "title": "Wafer map defect pattern classification based on convolutional neural network features and error correcting output codes", "venue": "J. Intell. Manuf.", "year": 2020 }, { "abstract": "An automatic defect classification (ADC) system identifies and classifies wafer surface defects using scanning electron microscope images. By classifying defects, manufacturers can determine whether the wafer can be repaired and proceed to the next fabrication step. Current ADC systems have high defect detection performance. However, the classification power is poor. In most work sites, defect classification is performed manually using the naked eye, which is unreliable. This paper proposes an ADC method based on deep learning that automatically classifies various types of wafer surface damage. In contrast to conventional ADC methods, which apply a series of image recognition and machine learning techniques to find features for defect classification, the proposed model adopts a single convolutional neural network (CNN) model that can extract effective features for defect classification without using additional feature extraction algorithms. Moreover, the proposed method can identify defect classes not seen during training by comparing the CNN features of the unseen classes with those of the trained classes. Experiments with real datasets verified that the proposed ADC method achieves high defect classification performance.", "author_names": [ "Sejune Cheon", "Hankang Lee", "Chang Ouk Kim", "Seok Hyung Lee" ], "corpus_id": 116334837, "doc_id": "116334837", "n_citations": 52, "n_key_citations": 1, "score": 0, "title": "Convolutional Neural Network for Wafer Surface Defect Classification and the Detection of Unknown Defect Class", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2019 }, { "abstract": "Increasing yield is a primary concern to integrated circuit manufacturing companies as it dictates the readiness of a new process for high volume manufacturing. In order to expedite the process of discovering yield issues, companies have started looking for ways to perform early prediction for such issues. This paper suggests the use of the support vector machines (SVMs) for early wafer classification. The choice of SVM is motivated by the model's ability to effectively classify multivariate, multimodal, and inseparable data points. This model uses multidimensional hyperplanes to separate and classify wafers into low yield and high yield classes. This paper includes a proposal for how the classification model can be applied for yield classification and how it can be adaptively updated in a manufacturing environment. We show how the values for the SVM parameters can be selected for best yield classification. Furthermore, performance evaluation is conducted on real manufacturing data, comparing the proposed SVM classifier to state of the art. Results show that in all cases, SVM consistently outperforms other methods with and without adaptive model updates. The experiments also show that all classifiers' performances depend on yield thresholds. It is also shown that the classification model can be built and executed using a reduced set without compromising its accuracy.", "author_names": [ "R Baly", "Hazem Hajj" ], "corpus_id": 35786120, "doc_id": "35786120", "n_citations": 64, "n_key_citations": 5, "score": 0, "title": "Wafer Classification Using Support Vector Machines", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2012 }, { "abstract": "In the semiconductor industry, the testing section has always played an important role. The testing section often requires engineers to judge the defect, which wastes a lot of time and cost. The accurate classification can provide useful information for engineers through neural networks. In this paper, we present a method for wafer map data augmentation and defect classification. Data augmentation is based on CNN encoder decoder and the classification is based on depthwise separable convolutions. There are two datasets used, one is open dataset WM 811K and the other is built with a Taiwan company. We train two models with mobilenetV1 and V2 for the different datasets. The light weight deep convolution can reduce model parameters and calculations, which is very efficient for the testing house with large production volumes. On two different data sets, our proposed method can reduce the number of parameters by 30% and 95% and reduce the amount of calculation by 75% and 25% respectively. The test accuracy of the first dataset is 93.95% The second dataset test accuracy is 87.04% After the data augmentation, accuracy is increased to 97.01% and 95.09% respectively.", "author_names": [ "Tsung-Han Tsai", "Yu-Chen Lee" ], "corpus_id": 226293968, "doc_id": "226293968", "n_citations": 6, "n_key_citations": 1, "score": 1, "title": "A Light Weight Neural Network for Wafer Map Classification Based on Data Augmentation", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2020 }, { "abstract": "Wafer maps provide important information for engineers for detecting root causes of failure in a semiconductor manufacturing process. Thus, there has been active research into the automation of wafer map pattern classification. With recent advances in deep learning, a convolutional neural network (CNN) has yielded state of the art performance in wafer map pattern classification. Because a large amount of labeled training data is required, experienced engineers need to annotate large quantities of wafer maps manually which is costly. To construct a well performing CNN model with a lower labeling cost, we propose a cost effective wafer map pattern classification system based on the active learning of a CNN. In the system, a CNN model is constructed based on four main steps: uncertainty estimation, query wafer selection, query wafer labeling, and model update. By repetitively performing these steps, the performance of the CNN model is gradually and effectively increased. We compared several methods for uncertainty estimation and query wafer selection in our system. We demonstrated the effectiveness of the proposed system through experiments using real world data from a semiconductor manufacturer.", "author_names": [ "Jaewoong Shim", "Seokho Kang", "Sungzoon Cho" ], "corpus_id": 214281189, "doc_id": "214281189", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Active Learning of Convolutional Neural Network for Cost Effective Wafer Map Pattern Classification", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2020 } ]
applied physics letters ,104,21917(2014)
[ { "abstract": "Chuan Liu, Yong Xu, Gerard Ghibaudo, Xubing Lu, Takeo Minari, and Yong Young Noh Citation: Applied Physics Letters 104, 079902 (2014) doi: 10.1063/1.4866287 View online: http:/dx.doi.org/10.1063/1.4866287 View Table of Contents: http:/scitation.aip.org/content/aip/journal/apl/104/7?ver=pdfcov Published by the AIP Publishing Articles you may be interested in Evaluating injection and transport properties of organic field effect transistors by the convergence point intransfer length method Appl. Phys. Lett. 104, 013301 (2014) 10.1063/1.4860958 Erratum: \"Influence of dielectric dependent interfacial widths on device performance in top gate P(NDI2OD T2)field effect transistors\" [Appl. Phys. Lett.101, 093308 (2012) Appl. Phys. Lett. 101, 179901 (2012) 10.1063/1.4762831 Erratum: \"Poly(3 hexylthiophene) crystalline nanoribbon network for organic field effect transistors\" [Appl. Phys.Lett.96, 243304 (2010) Appl. Phys. Lett. 97, 189902 (2010) 10.1063/1.3512957 Comment on \"Depletion width measurement in an organic Schottky contact using a metal semiconductor field effect transistor\" [Appl. Phys. Lett.91, 083513 (2007) Appl. Phys. Lett. 97, 096101 (2010) 10.1063/1.3475395 Erratum: \"Electronic transport characteristics of electrolyte gated conducting polyaniline nanowire field effecttransistors\" [Appl. Phys. Lett.95, 013113 (2009) Appl. Phys. Lett. 95, 079901 (2009) 10.1063/1.3213393", "author_names": [ "Chuan Liu", "Yong Xu", "Gerard Ghibaudo", "Xubing Lu", "Takeo Minari", "Yong-Young Noh" ], "corpus_id": 121484367, "doc_id": "121484367", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Erratum: \"Evaluating injection and transport properties of organic field effect transistors by the convergence point in transfer length method\" [Appl. Phys. Lett. 104, 013301 (2014)", "venue": "", "year": 2014 }, { "abstract": "Enhanced flexoelectricity in perovskite ceramics and single crystals has been reported before. In this letter, 3 3 ceramic ceramic Ba0.6Sr0.4TiO3/Ni0.8Zn0.2Fe2O4 composite with a colossal permittivity was employed in the conventional pure bending experiment in order to examine the transverse flexoelectric response. The measured flexoelectric coefficient at 30 Hz is 128 mC/m and varies to 16 mC/m with the frequency increasing from 30 Hz to 120 Hz, mainly due to the inverse correlation between the permittivity and the frequency. This result reveals the permittivity dependence of flexoelectric coefficient in the frequency dispersion materials, suggesting that the giant permittivity composites can be good flexoelectric materials. Disciplines Engineering Physical Sciences and Mathematics Publication Details Shu, L. Huang, W. Kwon, S. Ryung. Wang, Z. Li, F. Wei, X. Zhang, S. Lanagan, M. Yao, X. Jiang, X. (2014) Converse flexoelectric coefficient f(1212) in bulk Ba0.67Sr0.33TiO3. Applied Physics Letters, 104 (23) 232902 1 232902 6. Authors Longlong Shu, Wenbin Huang, Seol Ryung Kwon, Zhao Wang, Fei Li, Xiaoyong Wei, Shujun Zhang, Michael T. Lanagan, Xi Yao, and Xiaoning Jiang This journal article is available at Research Online: http:/ro.uow.edu.au/aiimpapers/3070 Converse flexoelectric coefficient f1212 in bulk Ba0.67Sr0.33TiO3 Longlong Shu, Wenbin Huang, Seol Ryung Kwon, Zhao Wang, Fei Li, Xiaoyong Wei, Shujun Zhang, Michael Lanagan, Xi Yao, and Xiaoning Jiang Citation: Appl. Phys. Lett. 104, 232902 (2014) doi: 10.1063/1.4882060 View online: https:/doi.org/10.1063/1.4882060 View Table of", "author_names": [ "Longlong Shu", "Wenbin Huang", "Seol ryung Kwon", "Zu-Jun Wang", "Fei Li", "Xiaoyong Wei", "Shujun Zhang", "Michael T Lanagan", "Xi Yao", "Xiaoning Jiang" ], "corpus_id": 54707747, "doc_id": "54707747", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Converse flexoelectric coefficient f 1212 in bulk Ba 0 67 Sr 0 33 TiO 3", "venue": "", "year": 2014 }, { "abstract": "A thin film based Erbium doped Tellurium Oxide (TeO2) waveguide amplifier producing gain from 1500nm to 1640nm when pumped at 980nm is demonstrated. At measured internal gains exceeding 14dB lasing due to end facet reflection set in producing the first tellurite waveguide laser. High gains were observed despite significant upconversion, whose impact appears to be mitigated to some extent by residual OH contamination. The device displayed no photosensitive effects from either the high pumping intensities used or the intracavity intensity at 1550nm. (c)2014 Optical Society of America OCIS codes: (130.3120) Integrated optics devices; (140.3210) Laser amplifier; (160.4670) Optical materials; (230.7370) Waveguides. References and links 1. S. Berneschi, G. Nunzi Conti, G.C. Righini, \"Planar waveguide ampflifiers,\" Ceramist: Jnl Korean Ceram. Soc. 10, 75 85 (2007) 2. G.N. van den Hoven, R.J.I.M. Koper, A. Polman, C. van Dam, J.W.M. van Uffelen, M.K. Smit, \"Net optical gain at 1.53 mm in Er doped Al2O3 waveguides on silicon,\" Applied Physics Letters 68, 1886 1888 (1996) 3. J.E. Roman, M. Hempstead, C. Ye, S. Nouh, P. Camy, P. Laborde, C. Lerminiaux, \"1.7 mm excited state absorption measurement in erbium doped glasses,\" Appl. Phys. Lett. 67, 470 472 (1995) 4. Y.C. Yan, A.J. Faber, H. de Waal, P.G. Kik, A. Polman, \"Erbium doped phosphate glass waveguide on silicon with 4.1 dB/cm gain at 1.535 m,\" Applied Physics Letters 71, 2922 2922 (1997) 5. G. Della Valle, A. Festa, G. Sorbello, K. Ennser, C. Cassagnetes, D. Barbier, S. Taccheo, \"Single mode and high power waveguide lasers fabricated by ion exchange,\" Opt. Express 16, 12334 12341 (2008) 6. G. Della Valle, R. Osellame, G. Galzerano, N. Chiodo, G. Cerullo, P. Laporta, O. Svelto, U. Morgner, A.G. Rozhin, V. Scardaci, A.C. Ferrari, \"Passive mode locking by carbon nanotubes in a femtosecond laser written waveguide laser,\" Applied Physics Letters 89 (2006) 7. G. Della Valle, S. Taccheo, P. Laporta, G. Sorbello, E. Cianci, V. Foglietti, \"Compact high gain Erbiumytterbium doped waveguide amplifier fabricated by Ag Na ion exchange,\" Electronics Letters 42, 632 633 (2006) 8. R. Osellame, G. Della Valle, N. Chiodo, S. Taccheo, P. Laporta, O. Svelto, G. Cerullo, \"Lasing in femtosecond laser written optical waveguides,\" Applied Physics A: Materials Science Processing 93, 17 26 (2008) 9. R.A.H. El Mallawany, Tellurite glasses handbook: physical properties and data (CRC Press, US, 2002) 10. C.E. Chryssou, F. Di Pasquale, C.W. Pitt, \"Er doped channel optical waveguide amplifiers for WDM systems: A comparison of tellurite, alumina and Al/P silicate materials,\" IEEE Journal on Selected Topics in Quantum Electronics 6, 114 121 (2000) 11. S. Dai, C. Yu, G. Zhou, J. Zhang, G. Wang, L. Hu, \"Concentration quenching in Erbium doped tellurite glasses,\" Journal of Luminescence 117, 39 45 (2006) 12. A. Mori, \"Tellurite based fibers and their applications to optical communication networks,\" Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi/Journal of the Ceramic Society of Japan 116, 1040 1051 (2008) 13. S. Shen, A. Jha, X. Liu, M. Naftaly, K. Bindra, H.J. Bookey, A.K. Kar, \"Tellurite glasses for broadband amplifiers and integrated optics,\" J Am Ceram Soc 85, 1391 1395 (2002) 14. T.T. Fernandez, G. Della Valle, R. Osellame, G. Jose, N. Chiodo, A. Jha, P. Laporta, \"Active waveguides written by femtosecond laser irradiation in an Erbium doped phospho tellurite glass,\" Optics Express 16, 15198", "author_names": [ "Khu Vu", "Sajjad Farahani", "Steve J Madden" ], "corpus_id": 40417287, "doc_id": "40417287", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "980 nm pumped Erbium Doped Tellurium Oxide Planar Rib Waveguide Laser and Amplifier with Gain in S C and", "venue": "", "year": 2014 }, { "abstract": "Zai Guang Dian Dui Kang Ying Yong Zhong ,2.7 mmHe 4.3 mmBo Duan De Shuang Zhong Hong Wai Ji Guang Shou Dao Te Bie Guan Zhu Qi Jin Yi You De Ji Zhu Tu Jing Du Zhi Neng Fen Bie Chan Sheng Qi Zhong Yi Ge Bo Duan De Ji Guang ,Qie Chan Sheng Fang Fa Dan Yi Zhuan Huan Xiao Lu Shou Dao Yi Ding Xian Zhi Xin Jin Yan Jiu Biao Ming ,Ru Guo Cai Yong Te Ding Bo Chang 1.658 mmDe Ji Guang Zuo Wei Beng Pu Guang Yuan ,Tong Guo Fei Xian Xing Can Liang Guo Cheng ,Ke Yi Tong Shi Huo De 2.7 mm, 4.3 mmLiang Ge You Yong Bo Duan De Ji Guang Shu Chu Shuang Zhong Hong Wai Ji Guang Fang An De Nan Dian He Guan Jian Zai Yu 1.658 mmZhe Ge Te Ding Bo Chang Shi Qian Suo Wei You De Bu Neng You Xi Tu Chi Zi Zhi Jie Fu She Chan Sheng Ling Yi Ge Te Shu Bo Duan Ji Guang Ying Yong De Lei Si Li Zheng Wei :Zai Da Qi Tuan Liu Zi Gua Ying Guang Xue Bo Qian Xiao Zheng Xi Tong Zhong ,Na Dao Xing De Xin Biao Guang Yuan Suo Xu De 589.1591 nmZhai Dai Huang Guang Ji Guang (Dui Ying Na Yuan Zi D2Pu Xian )Ye Shi Yi Ge Chang Gui Fang Fa Bu Neng Zhi Jie Chan Sheng De Te Ding Bo Chang Yin Ci ,Yan Jiu Jie Jue Chan Sheng Ge Lei Te Ding Bo Chang Ji Guang De Ji Zhu Tu Jing He Fang Fa ,Shi Shi Fen Bi Yao He You Yi Yi De Zuo Wei Dian Xing Shi Li ,Ben Lun Wen Jiang Zhu Yao Zhen Dui 1.6 mmBo Duan De Xu Qiu ,Kai Zhan Xi Tong De Li Lun He Shi Yan Yan Jiu Zai Li Lun Yan Jiu Ji Chu Shang ,Ti Chu Bing You Hua She Ji Liao Yi Tiao Ju You Pu Gua Yi Yi De Ji Lian Xing Ji Zhu Lu Xian Zhai Xian Kuan 1.5 mm Er:YbGong Xian Guang Xian Ji Guang Beng Pu 1.6 mmBo Duan La Man Guang Xian Ji Guang Qi ;Zai Shi Yan Shang Cheng Gong Shi Xian Liao Fu Gai 1.5, 1.6 mmBo Duan De Zhai Dai Ke Diao Xie Ji Bo Chang Suo Ding Ji Guang Shu Chu Huo De Fa Ming Zhuan Li Shou Quan Tong Guo Gai Bian Zeng Yi Guang Xian Chang Du ,Bing Yun Yong Ti Bu La Ge Guang Zha (VBG)Bo Chang Diao Xie ,Shou Ci Zai Er:YbGong Xian Guang Xian Ji Guang Qi Zhong Huo De Liao Tong Shi Fu Gai C bandHe L bandDe Ke Diao Xie Ji Guang Shu Chu ;Yun Yong Shuang VBGGuang Pu Zhai Hua Ji Zhu ,Huo De Liao Tong Lei Ji Zhu Zui Zhai Xian Kuan Xiao Yu ~38 pmHe 19.4 WGong Lu De Ji Guang Shu Chu Zai Yi Zhai Dai 1545 nm Er:YbGong Xian Guang Xian Ji Guang Beng Pu Jian Bian Zhe She Lu Duo Mo Tong Xin Guang Xian He Te Shu She Ji De Shuang Bao Ceng La Man Guang Xian ,Ying Yong VBGYu Bo Chang Diao Xie Bo Chang Suo Ding Ji Guang Pu Zhai Hua ,Shi Xian Liao 1.6 mmBo Duan 10.5 WGong Lu Tong Lei Ji Zhu Zui Zhai Xian Kuan 0.1 nmDe Ji Guang Shu Chu He Zui Da 37 nmDe Diao Xie Fan Wei ;Chan Shu Liao La Man Guang Xian Zhong SRSDe Guang Shu Jing Hua Zuo Yong ,Huo De Jin Yan She Ji Xian De StokesJi Guang Shu Chu Lun Wen Qu De Yi Xi Lie Chuang Xin Cheng Guo ,Fa Biao Liao Duo Pian Lun Wen Bao Gao ,Bao Gua SCILun Wen 5Pian EILun Wen 1Pian Xue Zhu Hui Yi Bao Gao 2Pian ,Yi Ji Shou Quan Fa Ming Zhuan Li Yi Xiang Lun Wen De Zhu Yao Nei Rong He Chuang Xin Dian You Yi 1.5 mmBo Duan Er:YbGong Xian Guang Xian Ji Guang Qi 1. Li Yong VBGZuo Wei Bo Chang Xuan Ze Yuan Jian ,Cai Yong Liang Duan Bu Tong Chang Du (7 m, 17 m)De Er:YbGong Xian Zeng Yi Guang Xian ,Fen Bie Shi Xian Liao Gong Zuo Bo Chang Tong Shi Fu Gai C band He L bandDe Kuan Diao Xie Ji Guang Shu Chu Gai Gong Zuo Fa Biao Zai Qi Kan IEEE Photonics Technology Letters 25(15) 1488 (2013)Shang 2. Shou Ci Jiang Shuang VBGGuang Pu Zhai Hua Ji Zhu Ying Yong Yu Er:YbGong Xian Guang Xian Ji Guang Qi Zhong ,Huo De Liao Zhong Xin Bo Chang Wei 1545.3 nm, Xian Kuan Xiao Yu ~38 pm, Gong Lu Wei 19.4 WDe Ji Guang Shu Chu Zai Jin Yi Bu De Shi Yan Zhong ,Jiang Shuang VBGYi Bing Lian Pai Lie De Fang Shi Ying Yong Dao Er:YbGong Xian Guang Xian Ji Guang Qi Zhong ,Shi Xian Liao Shuang Bo Chang Du Li De Lian Xu Ke Diao Xie Shu Chu ,Shuang Bo Chang Jian Ju Cong 0.3 nmDao 29.2 nm,Dang Bo Chang Jian Ju Wei 0.3 nmShi ,Huo De Liao Zui Da Gong Lu 17.9 WShu Chu ,Xie Xiao Lu Da 28.6% Liang Xiang Gong Zuo Fen Bie Fa Zai Zai Qi Kan IEEE Journal of Quantum Electronics 50(2) 88 (2014) Applied Physics Express 7(3) 032702 (2014)Shang 3. Jie He Guang Xian Ji Guang Qi You Liang De San Re Neng Li Yu Ti Kuai Zeng Yi Jie Zhi Neng Liang Cun Chu Rong Liang Da De You Dian ,Shou Ci Jiang Kuan Diao Xie Er:YbGong Xian Guang Xian Ji Guang Zuo Wei Tm:YAGTao Ci Ji Guang Qi Beng Pu Yuan ,Huo De Liao Zhong Xin Bo Chang Wei 2013.2 nm, Zui Da Gong Lu Wei 3.9 WDe Ji Guang Shu Chu Gai Gong Zuo Fa Biao Zai Qi Kan Applied Physics Express 6(3) 092107 (2013)Shang Er 1.6 mmBo Duan La Man Guang Xian Ji Guang Qi 1. Dui Yu Jian Bian Zhe She Lu Duo Mo Guang Xian De La Man Guang Xian Ji Guang Qi ,Zai Beng Pu Guang Xian Xing Xi Shou Jin Si Tiao Jian Xia ,Li Yong Lang Bo Han Shu (Lambert function)Tui Dao Chu Liao Miao Shu Duo Mo Guang Xian Zhong Shou Ji La Man San She (SRS)Guo Cheng De Bo Dong Fang Cheng De Jie Xi Jie ,Bing Jiang Qi Ying Yong Dao Shi Ji De La Man Guang Xian Ji Guang Qi She Ji He Can Shu You Hua Zhong ,Qu De Liao Jiao Hao De Xiao Guo 2. Jiang Bo Chang Suo Ding De 1545 nm Er:YbGong Xian Guang Xian Ji Guang Qi Zuo Wei Beng Pu Yuan ,Zai Ji Yu Pu Tong Jian Bian Zhe She Lu Duo Mo Tong Xin Guang Xian He Te Shu She Ji De Shuang Bao Ceng La Man Guang Xian De La Man Guang Xian Ji Guang Qi Zhong Fen Bie Shi Xian Liao Jin Yan She Ji Xian De 1.658 mm StokesJi Guang Shu Chu Chan Shu Liao Jian Bian Zhe She Lu Duo Mo Guang Xian Zhong SRSDe Guang Shu Ji Jing Zuo Yong ,Fen Xi Liao Jie Yue Xing Zhe She Lu Duo Mo Guang Xian Zhong Bu Cun Zai Gai Guang Shu Jing Hua Zuo Yong De Yuan Yin 3. Zai Ji Yu Jian Bian Zhe She Lu Guang Xian De La Man Guang Xian Ji Guang Qi Zhong ,Zi You Yun Zhuan Zhuang Tai Xia Huo De Liao Zui Gao Gong Lu Wei 12.3 WDe Ji Guang Shu Chu ,Li Yong VBGBo Chang Suo Ding Hou ,Shu Chu Ji Guang Xian Kuan Jin Wei ~0.1 nm,Zhe Shi Mu Qian Suo Bao Dao De Wa Liang Ji La Man Guang Xian Ji Guang Qi Zhong Suo Huo De De Zui Zhai Xian Kuan ;Bo Chang Diao Xie Yun Zhuan Shi Huo De Liao Cong 1638.5 nmDao 1675.1 nmGong 37 nmDe Diao Xie Fan Wei ,Zhe Ye Shi La Man Guang Xian Ji Guang Qi Xiang Dang Gong Lu Shu Chu Xia Zui Kuan De Bo Chang Diao Xie Fan Wei Geng Kuan De Bo Chang Diao Xie Fan Wei Ke Wang Tong Guo Gai Bian Beng Pu Yuan De Gong Zuo Bo Chang Shi Xian Gai Gong Zuo Fa Biao Zai Qi Kan Optics Express 22(6) 6605 (2014)Shang ,Qie Gai Ke Diao Xie La Man Guang Xian Ji Guang Qi Yi Huo Fa Ming Zhuan Li Shou Quan (Shou Quan Hao :CN 102761048) 4. Dui Bao Ceng Beng Pu De La Man Guang Xian Ji Guang Qi Jin Xing Liao Chu Bu De Shi Yan Tan Suo Yan Jiu Chan Shu Liao Shuang Bao Ceng La Man Guang Xian Can Shu She Ji De Ji Ben Zhun Ze He Shuang Bao Ceng La Man Guang Xian Zhong De SRSHe Mo Shi Ji Fa Guo Cheng ,Bing Zui Zhong Zhi Cheng Shuang Bao Ceng La Man Guang Xian Zai Zi You Yun Zhuan He VBGBo Chang Suo Ding De Bao Ceng Beng Pu La Man Guang Xian Ji Guang Qi Zhong Fen Bie Shi Xian Liao Gong Lu Wei 13.2 W, 10.4 W De 1.658 mm StokesJi Guang Shu Chu Dui Bao Ceng Beng Pu La Man Guang Xian Ji Guang Qi De Jin Yi Bu Gong Lu Ding Biao Fang Da Gei Chu Liao Fen Xi He Tao Lun", "author_names": [ "" ], "corpus_id": 126307833, "doc_id": "126307833", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Zhai Xian Kuan Er:YbGong Xian Guang Xian Ji Guang Beng Pu 1.6 mmBo Duan La Man Guang Xian Ji Guang Qi Yan Jiu", "venue": "", "year": 2014 }, { "abstract": "This editorial contains an overview of the contents of the current issue of the Photonics Letters of Poland, devoted mainly to optical metrology. A series of 14 papers deals with both technology as well as pure and applied physics. The scientific topic of the Photonic Letters of Poland, vol. 6(4)/2014 pertains measurements and characterization of photonic structures and systems as well as optical waveguides and nanolayers. The common denominator of all articles qualified for publication is widely understood, highly specialized optical metrology. The current issue of PLP presents investigations carried out in selected Polish scientific and research centers. The group from the Institute of Electron Technology in Warsaw has presented very recent results of investigations into quantum cascade lasers highly technologically advanced systems. A paper of the group from West Pomeranian University of Technology in Szczecin is devoted to analyses and investigations of quantum wells structures The authors from the Department of Optoelectronics at the Silesian University of Technology (SUT) in Gliwice present in several papers analyses, studies and researches concerning integrated optics structures including: interference, multimode interference, structures and systems of differential interferometry. The group from this Department also shows researches of topography and morphology of graphene and graphene oxide with respect to their application in optical and electrical sensors. The current issue contains also the work, in which the results of investigations are presented into optical fibers in terms of their application in optical telecommunications carried out by the Group from the Faculty of Electronics at the Wroclaw University of Technology. Birefringence measurements of polymer photonic crystal fibers infiltrated with liquid crystals by using the effect of light depolarization are presented by the authors from the Faculty of Physics at the Warsaw University of Technology. E mail: Tadeusz.Pustelny@polsl.pl In the paper entitled \"A low temperature operated NO2 gas POF sensor based on conducting graft polymer\" from the Department of Optoelectronics at SUT in Gliwice novel results are presented of investigations concerning a high sensitive gas sensor based on a polymer optical fiber. Polymer optical fibers are also the topic of the paper elaborated by a group of the Optical Fiber Technology Laboratory at the University of Lublin. The Group has examined the impact of electromagnetic radiation of high energy on mechanical and optical properties of polymeric materials for their application in the production of optical fibers. A group from the Gdansk University of Technology has presented the possibility of using polarization sensitive optical coherence tomography in the inspection of ceramic materials. A group from the Department of Metrology and Optoelectronics at the Poznan University of Technology presents a new approach to objective evaluation of human visual acuity. Another group from the Faculty of Physics at the Warsaw University of Technology shows the results of their studies on the influence of pitch and birefringence on solitons propagation at the disclination lines in a wedgeshaped planarly oriented sample of the chiral nematic liquid crystal. A very interesting subject concerning the application of a multi camera 3D Digital Image Correlation (DIC) system with the procedure of spatial data stitching is presented by the group from the Faculty of Mechatronics at the Warsaw University of Technology. The system diversifies single DIC setup capabilities used for displacement and strain measurements of big and complex structures such as industrial installations. It should be recognized that the papers contained in the volume 6(4)/2014 are interesting, and the investigations presented in the articles will be continued. Highly Specialized Optical Metrology", "author_names": [ "Tadeusz Pustelny" ], "corpus_id": 116631336, "doc_id": "116631336", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Highly Specialized Optical Metrology", "venue": "", "year": 2014 }, { "abstract": "http:/dx.doi.org/10.1016/j.patrec.2014.06.004 0167 8655/ 2014 Published by Elsevier B.V. This Special Edition in Celebration of Maria Petrou, was conceived shortly after she died in October 2012 and was in response to friends and colleagues who wanted to remember both her personal warmth and exceptional scientific achievements. The idea was to have a variety of contributions including novel scientific articles, reviews of topics close to Maria's areas of interest, and personal recollections from friends and colleagues. The call for papers was issued in May 2013 and resulted in 27 submissions. Of these about 8 were of a non technical nature and have been edited together to form the 'Homage to Maria Petrou' which is a compendium of recollections of various interactions with Maria, spanning her whole career. The remaining articles were of a technical nature, and have been peer reviewed according to the usual process followed in Pattern Recognition Letters. This peer review has produced 9 revised papers, which are also included in the Special Edition. These papers are authored by former students, colleagues and followers of Maria's work. All cite her contributions to the field and place themselves in the context of her work. Several of the articles list Maria as a posthumous co author. The technical contributions as follows: The paper 'Progress in the restoration of image sequences are degraded by atmospheric turbulence' by Ronen Gal, Nahum Kiryati and Nir Sochen reflects Maria's long standing interest in remote sensing, and explains how atmospheric degradation can be overcome in motion sequences. This interest in remote sensing was one of her earliest in the field of image analysis, and grew out of her first post in the area as a postdoc in the Department of Geography at Reading University. This lead her to work extensively on the problem of mixed pixels, and this interest is reflected in the paper 'Subpixel temporal spectral imaging' authored by former student Olga Duran and posthumously by Maria herself. Finally under the heading of remote sensing, a second posthumous paper 'A rule based classification methodology to handle uncertainty in habitat mapping employing evidential reasoning and fuzzy logic' authored by Zisis Petrou et al. describes how her work in AI and pattern recognition can be brought to bear on image interpretation problems in remote sensing. Maria always described herself as having a soft spot for geometry, and ascribed this to sharing her nationality with Pythagoras. The paper 'Rotation invariant co occurrence features based on digital circles and discrete Fourier transform' by Antonio Fernandez and Francesco Bianconi builds on this interest together with her long standing fascination with the Hough transform to present a new shape characterisation technique. Maria enjoyed teaching and preparing innovative teaching material. She also thought a great deal about how people learn and how you should best help them to learn. Many of her ideas here influenced the development of the tower of knowledge which is described in 'Tower of Knowledge for Scene Interpretation: A Survey' by Mai Xu and Zulin Wang. After first moving to Surrey, Maria developed an interest in the renormalisation group approach to image processing. This was a natural direction for her not only since the method draws on ideas from physics, but also that the original work in this area was performed by fellow Greek, Basilis Gidas. In the paper 'Fast pose invariant face recognition using super coupled multiresolution Markov Random Fields on a GPU' by Shervin Rahimzadeh Arashloo and Josef Kittler, the renormalisation group approach is applied to face recognition and efficiently implemented on a GPU. In her first post in computer vision at Reading University, Maria worked on an Alvey project with David Hogg, and was fascinated by his then pioneering work on modelling walking people. The paper 'Identification of people walking along curved trajectories' by Yumi Iwashita, Koichi Ogawara and Ryo Kurazume, captures this long standing interest, as does the paper 'Human Activity Recognition From 3D Data: A Review' by Lu Xia and Jake Aggarwal, which shows how far this field has moved over the past 25 years. As a physicist by training, Maria was instinctively drawn to problems involving light, and this influenced her recent work on photometric stereo. The papers 'Error analysis of photometric stereo with colour lights' by Martin Klaudiny and Adrian Hilton and 'Cast Shadows estimation and synthesis using the Walsh Transform' by Vasileios Argyriou, Ferdinand Redelinghuys and Maria herself, both address this research interest, with new insights into photometric stereo and how it can be employed in the real world. In addition to the scientific papers and the compendium of recollections, this special edition also contains accounts of her work at the University of Surrey and CERTH in Thessaloniki, together with a reprint of her obituary which appeared in the Guardian. We thank the authors of the technical papers and the personal recollections for providing us with the material for this celebration of Maria's life. We also thank Gabriella Sanniti di Baja for encouraging us to embark on editing it, and for her patience when the project ran slowly. We are also very grateful to the staff at Elsevier, especially Journal Manager Janet Amali Joseph who helped us bring the special edition into being. This is of course just one of several tributes to Maria. There will be a workshop in the Autumn of 2014 at CERTH to celebrate her scientific achievements. The IAPR, of which Maria served as both Newsletter Editor and Treasurer, among other posts, plans to remember Maria through a named biennial award to a female scientist. At the time of going to press, details of the award are still being discussed, but should be finalised in time for approval at the IAPR Governing Board Meeting in Stockholm, and an announcement during ICPR.", "author_names": [ "Edwin R Hancock", "Josef Kittler" ], "corpus_id": 45223232, "doc_id": "45223232", "n_citations": 3, "n_key_citations": 0, "score": 2, "title": "Celebrating the life and work of Maria Petrou", "venue": "Pattern Recognit. Lett.", "year": 2014 }, { "abstract": "El objetivo de esta tesis es contribuir al desarrollo de circuitos complejos en chips fotonicos de silicio. Para ello, se centra en dos retos principales: Por un lado, trata de elucidar la dinamica temporal de los efectos no lineales en silicio, especialmente la interaccion de los portadores libres con los pulsos opticos en el dominio del tiempo. Por otro lado, la tesis pretende contribuir a la miniaturizacion de los circuitos fotonicos mediante la integracion de guias fotonicas con guias plasmonicas.Entre los resultados mas destacables de esta tesis se encuentra la observacion, por primera vez, de compresion de pulsos de picosegundos mediante el efecto soliton (Nature Communications 5, 3160, 2014) Hasta la fecha no habia sido posible esta demostracion debido a la fuerte presencia de absorcion de dos fotones y portadores libres en longitudes de onda de comunicaciones. Este hito ha sido posible gracias al uso de una guia cristal fotonico con luz lenta y su dispersion especialmente disenada. En esta misma linea de investigacion se ha logrado tambien el descubrimiento de nuevos efectos no lineales en el dominio del tiempo relacionados con la presencia de los portadores libres en la guia. Incluso mas importante es la propuesta de usar la dispersion de la guia como mecanismo de control para los efectos generados por los portadores libres, resolviendo el problema mas grave de la optica no lineal en silicio.Otro resultado destacable es la demostracion numerica de acoplamiento eficiente entre guias de cristal fotonico y lineas de transmision plasmonicas en el infrarrojo medio, que presenta gran potencial en la miniaturizacion de circuitos en esta region del espectro (Applied Physics Letters 104, 011105 2014).Esperamos que los resultados presentados en esta tesis conlleven un avance en fotonica de silicio, posibilitando mayor funcionalidad y miniaturizacion de circuitos fotonicos en una plataforma compatible con las capacidades de fabricacion de silicio.", "author_names": [ "Andrea Blanco Redondo" ], "corpus_id": 127553625, "doc_id": "127553625", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Linear and nonlinear devices in silicon photonic waveguides", "venue": "", "year": 2014 }, { "abstract": "We report on the experimental observation of coherent phonon boundary scattering in micro scale phononic crystals (PnCs) at room temperature. We show that the neglecting coherent boundary scattering leads to gross overestimation of the measured thermal conductivities of the PnC samples. We introduce a hybrid model that accounts for partial coherent and partial incoherent phonon boundary scattering. Excellent agreement with the experiment is achieved. Almost all physical processes produce heat as a byproduct making thermoelectric (TE) systems very attractive for energy scavenging applications. Energy conversion in TE devices is based on the so called Peltier effect 1 Here the temperature gradient resulting from expelled heat is used to force electronic transport resulting in an electric current. As such, heat transported via phonons represents a leakage mechanism and serves to reduce the efficiency of TE systems. Indeed the inability to suppress or eliminate the relative phonon contribution to thermal transport as compared to the electronic one has hindered the development of efficient TE devices. Recently, it has been proposed that coherent boundary scattering in micro scale phononic crystals (PnCs) may hold the key to solving this problem by scattering phonons with minimal influence on electrons 2 4 PnCs are artificial structures with a periodic variation in mechanical impedance brought about by the introduction of holes or plugs of one material into a homogenous matrix of another 5 8 This periodic variation results in rich phonon dispersion with unusual behaviors 9 In this communication, we focus on micro scale PnCs formed by the introduction of air holes in a Si matrix with minimum feature sizes 100nm. As a phonon population traverses such a lattice, it can undergo two types of scattering processes: simple incoherent scattering as a result of encountering a boundary; and coherent Bragg like 7 scattering due to the periodic topology of the artificial lattice of air holes. In the first type, it is assumed that the phonons will retain no phase information after each scattering event. This implies that the phonon dispersion remains unaltered due to the introduction of the air holes. In the second type, on the other hand, it is assumed that the phase is preserved throughout several scattering events thus enabling coherent interference to occur. Consequently, this would imply a modified phonon dispersion that is sensitive to the topology of the PnC air hole lattice. Practically, this can have profound implications because: while incoherent boundary scattering depends only on the shape, size, and separation of the holes; coherent boundary scattering additionally depends on the symmetry and topology by which these holes are distributed. Thus, the existence of coherent scattering would allow one to further reduce the thermal conductivity of the underlying material without the need for additional boundaries (e.g. more air holes) by simply altering the PnC topology. The claim of coherent phonon scattering in micro scale Si/Air PnCs at room temperature has generated widespread controversy in the literature given the relatively small wavelength characteristic of the phonon population dominating the thermal transport 3,10 14 Experimentally however, the thermal conductivity (k) of PnC samples have consistently been measured to be significantly lower than that of an unpatterned film 2,4,11,13,14 In fact far lower than what would be expected due to the combination of material removal and simple incoherent boundary scattering 2,4,13 thereby suggesting that another k reduction mechanism, possibly coherent scattering, must be taking place. The The 2nd Intenational Conference on Phononics and Thermal Energy Science (PTES2014) Shanghai, China, May 26 May 31, 2014 controversy was heightened by the discovery that ~50% of k in Si is carried by phonons with mean free paths (MFPs) from 100nm up to 1mm15, which was recently verified experimentally 16 Since it is logical to assume that a phonon remains coherent over its MFP, we suggest here that the MFP, rather than wavelength, should be used when judging whether or not coherent scattering events can take place. In which case, a large enough fraction of the phonon population could travel sufficient distances to experience the PnC lattice periodicity and thus undergo coherent scattering. We report on the experimental observation of coherent phonon boundary scattering in micro scale phononic crystals (PnCs) at room temperature. We investigate the existence of coherent phonon boundary scattering resulting from the periodic topology of the PnCs and its influence on the thermal in silicon. To delaminate incoherent from coherent boundary scattering, PnCs with a fixed minimum feature size, differing only in the unit cell topologies, were fabricated. A suspended island platform was used to measure the thermal conductivity. We show that the neglecting coherent boundary scattering leads to gross overestimation of the measured thermal conductivities of the PnC samples. We introduce a hybrid model that accounts for partial coherent and partial incoherent phonon boundary scattering. Excellent agreement with the experiment is achieved emphasizing the influence of coherent zone folding in PnCs. Our results yield conclusive evidence that significant room temperature coherent phonon boundary scattering does indeed take place. References 1 Slack, G. A. CRC Handbook of Thermoelectrics. (CRC Press, 1995) Hopkins, P. E. et al. Reduction in the Thermal Conductivity of Single Crystalline Silicon by Phononic Crystal Patterning. Nano Lett 11, 107 112, doi:Doi 10.1021/Nl102918q (2011) 3 Reinke, C. M. et al. Thermal conductivity prediction of nanoscale phononic crystal slabs using a hybrid lattice dynamics continuum mechanics technique. AIP Advances 1, 041403 041414 (2011) 4 Yu, J. K. Mitrovic, S. Tham, D. Varghese, J. Heath, J. R. Reduction of thermal conductivity in phononic nanomesh structures. Nature Nanotechnology, 5, 718 721, (2010) 5 Reinke, C. M. Su, M. F. Olsson, R. H. El Kady, I. Realization of optimal bandgaps in solid solid, solid air, and hybrid solid air solid phononic crystal slabs. Appl Phys Lett 98, doi:Artn 061912 Doi 10.1063/1.3543848 (2011) 6 Su, M. F. Olsson, R. H. Leseman, Z. C. El Kady, I. Realization of a phononic crystal operating at gigahertz frequencies. Appl Phys Lett 96, 053111 (053113 pp. doi:10.1063/1.3280376 (2010) 7 Olsson, R. H. III et al. in IEEE International Ultrasonics Symposium. 1150 1153. 8 El Kady, I. Olsson, R. H. III Fleming, J. G. Phononic band gap crystals for radio frequency communications. Appl Phys Lett 92, 233504 233501 233503, doi:10.1063/1.2938863 (2008) 9 Kushwaha, M. S. Halevi, P. Dobrzynski, L. Djafari Rouhani, B. Acoustic band structure of periodic elastic composites. Physical Review Letters 71, 2022 2025 (1993) 10 Hao, Q. Chen, G. Jeng, M. S. Frequency dependent Monte Carlo simulations of phonon transport in two dimensional porous silicon with aligned pores. Journal of Applied Physics 106, 114321 114310 (2009) 11 Tang, J. et al. Holey Silicon as an Efficient Thermoelectric Material. Nano Lett 10, 4279 4283, doi:10.1021/nl102931z (2010) 12 Jain, A. Yu, Y. J. McGaughey, A. J. H. Phonon transport in periodic silicon nanoporous films with feature sizes greater than 100 nm. Physical Review B 87, 195301 (2013) 13 Bongsang, K. et al. in Micro Electro Mechanical Systems (MEMS) 2012 IEEE 25th International Conference on 176 179 (2012) 14 El Kady, I. et al. Phonon Manipulation with Phononic Crystals. (Sandia National Laboratories, 2012) 15 Esfarjani, K. Chen, G. Stokes, H. T. Heat transport in silicon from first principles calculations. Physical Review B 84, 085204 (2011)", "author_names": [ "Ihab El-Kady", "Charles M Reinke", "Seyedhamidreza Alaie", "Drew F Goettler", "Mehmet F Su", "Zayd C Leseman" ], "corpus_id": 123791915, "doc_id": "123791915", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Thermal Transport in Micro Scale Phononic Crystals: Observation of Coherent Phonon Scattering at Room Temperature.", "venue": "", "year": 2014 }, { "abstract": "El principal objetivo de esta Tesis Doctoral es el estudio analitico y numerico de dispositivos multipuerta, MuG del ingles Multiple Gate, y compuestos semiconductores III V, como alternativas tecnologicas para continuar el proceso de escalado del transistor MOSFET mas alla del nodo tecnologico de 22nm [delAlamo2011] Con este objetivo, se han implementado simuladores electrostaticos y de transporte capaces de resolver las ecuaciones de Schrodinger, Poisson y Boltzmann en un gas de electrones unidimensional. El simulador electrostatico esta basado en la aproximacion de masa efectiva no parabolica [Jin2007] siendo capaz de tratar con geometrias, materiales y orientaciones arbitrarias para obtener las distribuciones de carga y potencial en la seccion transversal bidimensional de la estructura MuG [Marin2012] El simulador de transporte linealiza la ecuacion de transporte unidimensional de Boltzmann, usando la aproximacion de tiempo de relajacion del momento, MRT del ingles Momentum Relaxation Time, [Esseni2011] resolviendo el sistema resultante de manera implicta. Ademas incluye modelos novedosos de dispersion debida a rugosidad superficial [Stanojevic2013,Jin2013] cargas coulombianas [Ning1972,Gamiz1994,Gamiz2002] fonones bulk [Kotlyar2004,Jin2007, Ashcroft1976,Tienda2012] fonones opticos polares [OReagan2010,Wang1993,Leburton1992] y desorden por aleacion [Bastard1988,Pham2007] Adicionalmente, se ha desarrollado un modelo completamente analitico que describe el comportamiento electrostatico de nanohilos [Marin2012b] NW del ingles nanowire. Es, hasta donde alcanza nuestro conocimiento, la descripcion analitica mas completa de la distribucion de la carga y el potencial en NWs cilindricos fabricados con materiales III V presentada en la literatura hasta la fecha. El modelo proporciona expresiones analiticas para calcular la energia de las subbandas y las funciones de onda del valle Gamma, teniendo en cuenta la penetracion de la funcion de onda en el aislante y la discontinuidad en la masa efectiva en la interfaz entre el aislante y el semiconductor, asi como estadistica de Fermi Dirac, confinamiento bidimensional de los portadores y la no parabolicidad de la banda de conduccion. Tambien permite incluir un perfil arbitrario de estados en la interfaz. Haciendo uso de las aproximaciones numerica y analitica, se realizan varios estudios relevantes de caracter electrostatico y del transporte en Trigates y NWs. Estas dos estructuras son especialmente siginificativas puesto que constituyen las arquitecturas MuG mas consolidadas. Los Trigate introducen pocos cambios respecto al proceso de fabricacion planar tradicional, al mismo tiempo que incrementan el control electrosatico del canal [Radosavljevic2010,Colinge2004] Los NWs son la evolucion ultima de las arquitecturas MuG, proporcionando la mayor supresion de los efectos de canal corto [delAlamo2011] De esta manera, usando el enfoque analitico se estudia la influencia del tamano del dispositivo y el tipo de material en la carga en inversion, la corriente de drenador, la capacidad de puerta y la tension umbral en nanohilos III V [Marin2013,Marin2014] Para completar el estudio analitico, los simuladores numericos desarrollados se han utilizado para comprender el papel del valle L en las propiedades electrostaticas y de transporte, concluyendo que tiene un influencia no despreciable a medida que el tamano del dispositivo se reduce. El enfoque numerico se usa tambien para comparar el comportamiento de estructuras Trigate de Si y materiales III V. El impacto de la anchura del Trigate y de la puerta trasera es analizada, mostrando que: a) el incremento de la movilidad observado para Trigates III V se degrada cuando la anchura se reduce y b) el control de la puerta trasera sobre la tension umbral afecta directamente a la movilidad [Ruiz2013,Ruiz2013] Finalmente, la rugosidad superficial se revela como el principal mecanismo de dispersion limitador de la movilidad para la gran mayoria de tamanos y materiales a alto campo, siendo su comportamiento a bajo campo mas complicado y muy dependiente del tamano y material empleados. Referencias [Ashcroft1976] N.W. Ashcroft and N.D. Mermin. Solid state physics. Saunders College, 1976. [Bastard1988] G. Bastard. Wave mechanics applied to semiconductor heterostructures. Monographies de physique. Les Editions de Physique, 1988. [Colinge2004] J. P. Colinge. Multiple gate SOI MOSFETs. Solid State Electronics, 48:897,Jun 2004. [delAlamo2011] J.A. del Alamo. Nanometre scale electronics with III V compound semiconductors. Nature, 479:317, Nov 2011. [Esseni2011] D. Esseni, P. Palestri, and L. Selmi. Nanoscale MOS Transistors: Semi classical Transport And Applications. Cambridge University Press, New York. USA, 2011. [Gamiz1994] F. Gamiz, J. A. Lopez Villanueva, J. A. Jimenez Tejada, I. Melchor, and A. Palma. A comprehensive model for coulomb scattering in inversion layers. Journal of Applied Physics, 75:924, 1994. [Gamiz2002] F. Gamiz, F. Jimenez Molinos, J. B. Roldan, and P. Cartujo Cassinello. Coulomb scattering model for ultrathin silicon on insulator inversion layers. Applied Physics Letters, 80:3835, 2002. [Jin2007] S. Jin, M. V. Fischetti, and T. Tang. Modeling of electron mobility in gated silicon nanowires at room temperature: Surface roughness scattering, dielectric screening, and band nonparabolicity. Journal of Applied Physics, 102:083715, Oct 2006. [Jin2013] S. Jin, S. M. Hong, W. Choi, K. H. Lee, and Y. Park. Coupled drift diffusion (DD) and multi subband boltzmann transport equation (MSBTE) solver for 3D multi gate transistors. In Simulation of Semiconductor Processes and Devices (SISPAD) 2013 International Conference on, page 348, Sept 2013. [Kotlyar2004] R. Kotlyar, B. Obradovic, P. Matagne, M. Stettler, and M. D. Giles. Assessment of room temperature phonon limited mobility in gated silicon nanowires. Applied Physics Letters, 84:5270, 2004. [Leburton1992] J. P. Leburton. Optic phonon limited transport and anomalous carrier cooling in quantum wire structures. Physical Review B, 45:11022, 1992. [Marin2012] E. G. Marin, F. G. Ruiz, A. Godoy, I. M. Tienda Luna, and F. G amiz. Effect of interfacial states on the technological variability of Trigate MOSFETs. In Silicon Nanoelectronics Workshop (SNW) 2012 IEEE, 2012. [Marin2012] E. G. Marin, F. G. Ruiz, I. M. Tienda Luna, A. Godoy, P. Sanchez Moreno, and F. Gamiz. Analytic potential and charge model for III V Surrounding Gate MOSFETs. Journal of Applied Physics, 112:084512, Oct 2012. [Marin2013] E.G. Marin, F.J.G. Ruiz, I.M. Tienda Luna, A. Godoy, and F. Gamiz. Analytical gate capacitance modeling of III V nanowire transistors. IEEE Transactions on Electron Devices, 60(5):1590, May 2013. [Marin2014] E.G. Marin, F.G. Ruiz, I.M. Tienda Luna, A. Godoy, and F. Gamiz. Analytical model for the threshold voltage of III V nanowire transistors including quantum effects. Solid State Electronics, 92:28, Feb 2014. [Ning1972] T. H. Ning and C. T. Sah. Theory of scattering of electrons in a nondegenerate semiconductor surface inversion layer by surface oxide charges. Physical Review B, 6:4605, 1972. [OReagan2010] T. P. OReagan, M. V. Fischetti, B. Soree, S. Jin, W. Magnus, and M. Meuris. Calculation of the electron mobility in III V inversion layers with high dielectrics. Journal of Applied Physics, 108:103705, 2010. [Pham2007] A. T. Pham, C. Jungemann, and B. Meinerzhagen. Physics based modeling of hole inversion layer mobility in strained SiGe on insulator. IEEE Transactions on Electron Devices, 54:2174, 2007. [Radosavljevic2010] M. Radosavljevic, G. Dewey, J. M. Fastenau, J. Kavalieros, R. Kotlyar, B. Chu Kung, et al. Non planar, multi gate InGaAs quantum well field effect transistors with high k gate dielectric and ultra scaled gate to drain/gate to source separation for low power logic applications. In Electron Devices Meeting (IEDM) 2010 IEEE International, page 126, Dec 2010. [Ruiz2013] F. G. Ruiz, E. G. Marin, I. M. Tienda Luna, A. Godoy, C.Martinez Blanque, and F. Gamiz. Influence of the back gate bias on the electron mobility of a trigate MOSFETs. In Simulation of Semiconductor Processes and Devices (SISPAD) 2013 International Conference on, page 304, 2013. [Ruiz2012] F. G. Ruiz, E. G. Marin, I. M. Tienda Luna, A. Godoy, C.Martinez Blanque, and F. G ?miz. Back gate biasing influence on the electron mobility and the a threshold voltage of ultra thin box Multigate MOSFET. In Silicon Nanoelectronics Workshop (SNW) 2013 IEEE, 2012. [Stanojevic2013] Z. Stanojevic and H. Kosina. Surface roughness scattering in non planar channels: The role of band anisotropy. In Simulation of Semiconductor Processes and Devices (SISPAD) 2013 International Conference on, page 352, Sept 2013. [Tienda210] I. M. Tienda Luna, F. G. Ruiz, A. Godoy, E. G. Marin. and F. G amiz. Dependence of the phonon limited mobility in arbitrarily oriented si nanowires. In Computational Electronics (IWCE) 2010 15th International Workshop on, 2012. [Wang1993] T. Wang and T.W. Chen T. H. Hsieh. Quantum confinement effects on low dimensional electron mobility. Journal of Applied Physics, 74:426, 1993.", "author_names": [ "Nestor Ricardo Gonzalez Marin" ], "corpus_id": 125801873, "doc_id": "125801873", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Modeling and simulation of semiconductor nanowires for future technology nodes", "venue": "", "year": 2014 }, { "abstract": "In recent years, gallium phosphide based nanostructures, particularly indium gallium arsenide quantum dots (QD) embedded in gallium phosphide, have attracted interest of a growing number of research groups worldwide. InxGa1 xAs/GaP QDs are a possible solution for two current issues of the semiconductor industry: Monolithic integration of photonic devices based on III V semiconductors with silicon based electronics, and realization of a fast and non volatile electronic memory. The present thesis lays the groundwork for technological applications of InxGa1 xAs/ GaP QDs. The fabrication of InxGa1 xAs/GaP QDs by metalorganic vapour phase epitaxy and control of their structural properties like size and areal density via parameters of the epitaxial process are being developed. The structure of the QDs can be linked directly to their optical and electronic properties. Thus, the QDs can be tailored to fit a specific application. The electronic structure of InxGa1 xAs/GaP heterostructures generally is indirect in reciprocal and/or direct space due to high material strain. For the first time, the present work demonstrates a way to reduce this material strain and to fabricate InxGa1 xAs/GaP QDs with high efficient optical recombination channels, which is crucial for photonic devices. Besides technological applications, InxGa1 xAs/GaP QDs thereby present an ideal system to study fundamental interaction processes of QDs with surrounding material in dependence upon their electronic structure. First detailed analysis of the electronic structure of InxGa1 xAs/GaP QDs by means of optical and capacitance spectroscopy is presented. The theoretically predicted electronic structure of InxGa1 xAs/GaP QDs at the threshold between indirect and direct optical recombinations is confirmed. An evaluation of the technological potential of InxGa1 xAs/GaP QDs for electronic memories yields a storage time at room temperature three orders of magnitude larger compared to InxGa1 xAs/GaAs QDs. A non volatile memory can be realized by systematic further development of the GaP based material system. Teile dieser Arbeit wurden bereits veroffentlicht: G. Stracke, E. M. Sala, S. Selve, T. Niermann, A. Schliwa, A. Strittmatter und D. Bimberg, Indirect and direct optical transitions in In0.5Ga0.5As/GaP quantum dots Applied Physics Letters 104 (12) 123107 (2014) C. Prohl, A. Lenz, D. Roy, J. Schuppang, G. Stracke, A. Strittmatter, U. W. Pohl, D. Bimberg, H. Eisele und M. Dahne, Spatial structure of In0.25Ga0.75As/GaAs/GaP quantum dots on the atomic scale, Applied Physics Letters 102 (12) 123102 (2013) G. Stracke, A. Glacki, T. Nowozin, L. Bonato, S. Rodt, C. Prohl, A. Lenz, H. Eisele, A. Schliwa, A. Strittmatter, U. W. Pohl und D. Bimberg, Growth of In0.25Ga0.75As quantum dots on GaP utilizing a GaAs interlayer Applied Physics Letters 101 (22) 223110 (2012)", "author_names": [ "Gernot Stracke" ], "corpus_id": 183399118, "doc_id": "183399118", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Wachstum und Charakterisierung von InGaAs Quantenpunkten auf GaP Substraten", "venue": "", "year": 2014 } ]
n type organic semiconductor
[ { "abstract": "During the past decade, it has been shown that light matter strong coupling of materials can lead to modified and often improved properties which has stimulated considerable interest. While charge transport can be enhanced in n type organic semiconductors by coupling the electronic transition and thereby splitting the conduction band into polaritonic states, it is not clear whether the same process can also influence carrier transport in the valence band of p type semiconductors. Here we demonstrate that it is indeed possible to enhance both the conductivity and photoconductivity of a p type semiconductor rr P3HT that is ultrastrongly coupled to plasmonic modes. It is due to the hybrid light matter character of the virtual polaritonic excitations affecting the linear response of the material. Furthermore, in addition to being enhanced, the photoconductivity of rr P3HT shows a modified spectral response due to the formation of the hybrid polaritonic states. This illustrates the potential of engineering the vacuum electromagnetic environment to improve the optoelectronic properties of organic materials.", "author_names": [ "Kalaivanan Nagarajan", "Jino George", "Anoop Thomas", "Eloise Devaux", "Thibault Chervy", "S Azzini", "Kripa Joseph", "Abdelaziz Jouaiti", "Mir Wais Hosseini", "Anilesh Kumar", "Cyriaque Genet", "Nicola Bartolo", "Cristiano Ciuti", "Thomas W Ebbesen" ], "corpus_id": 221163496, "doc_id": "221163496", "n_citations": 15, "n_key_citations": 0, "score": 2, "title": "Conductivity and Photoconductivity of a p Type Organic Semiconductor under Ultrastrong Coupling.", "venue": "ACS nano", "year": 2020 }, { "abstract": "Abstract A p type organic thin film transistor (OTFT) was fabricated based on an axially substituted phthalocyanine (titanium phthalocyanine dichloride: TiCl2Pc) Molecular energies and atomic charge distributions of a series of axially substituted metal phthalocyanines were studied using measurements of their electrochemical properties and X ray photoemission spectroscopy, respectively. Based on these measurements, the relationship between the charge carrier transport types of the phthalocyanines in OTFTs and their substituted groups (metal and axial ligands) are discussed. The axially substituted electron withdrawing groups can effectively lower the LUMO energy and increase the charge separation, contributing to the realization of n type behavior, e.g. in SnCl2Pc. The electronegativity of the metal also affects the LUMO energies and charge distributions, such that TiCl2Pc is a p type semiconductor.", "author_names": [ "Chang Wook Song", "Ye Li", "Chen Gao", "Hao Zhang", "Ya-hui Chuai", "De Song" ], "corpus_id": 216213658, "doc_id": "216213658", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "An OTFT based on titanium phthalocyanine dichloride: A new p type organic semiconductor", "venue": "", "year": 2020 }, { "abstract": "A novel photoactive semiconductor (named as IDTOT 4F) with an A p D p A type configuration is synthesized. It contains an electron donating fused ring (D) as the core flanked with two p spacers and is end capped with two electron withdrawing units (A) The intramolecular charge transfer effect endows IDTOT 4F with strong and broad light absorption and a relatively narrow band gap (1.46 eV) Thin film optoelectrical devices based on IDTOT 4F exhibit both n type and p type switching behaviors. Besides, the p channel device shows significantly photoresponsive performance with the maximum P (photo/dark current ratio) R (photoresponsivity) and D* (detectivity) values of around 60, 0.07 AW 1, and 2.5 x 1010 Jones, respectively. Further, IDTOT 4F based optoelectrical devices exhibit good optical memory characteristics with a time constant t 1 of 4.6 h, indicating its applicability to nonvolatile optical memory devices. The results provide new insights into the photoresponsive behavior of fused ring semiconductors and pave the way for the design of nonvolatile optical memory devices.", "author_names": [ "Shiyu Feng", "Donghuan Dai", "Yao Lin", "Shuonan Chen", "Xiaosong Wu", "Weiguo Huang" ], "corpus_id": 221804992, "doc_id": "221804992", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "An A p D p A Type Organic Semiconductor Based Optoelectrical Device With Photo Response and Optical Memory Behaviors", "venue": "Frontiers in Materials", "year": 2020 }, { "abstract": "We have investigated the characteristics of bottom gate and top contact type field effect transistors fabricated with polycrystalline thin films of a liquid crystalline organic semiconductor, 2 decyl 7 phenyl benzothienobenzothiophene (Ph BTBT 10) with a p type dopant, tetrafluoro tetracyano quinodimethane (F4 TCNQ) We found that the contact resistance between the semiconductor and electrode was reduced from 3.0 kO cm to 1.2 kO cm by contact doping with F4 TCNQ, and to 0.9 kOcm by subsequent thermal annealing of the films, in which the F4 TCNQ dopant diffused from the surface to the interior of the Ph BTBT 10 thin film. In addition, we found that contact doped and thermally annealed devices showed higher mobility and smaller threshold voltage in short channel devices compared to pristine devices. We conclude that thermal diffusion of dopants to improve FET performance is an important technique.", "author_names": [ "Shun Takamaru", "Jun-ichi Hanna", "Hiroaki Iino" ], "corpus_id": 233815177, "doc_id": "233815177", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Use of doping to achieve low contact resistance in bottom gate top contact type organic transistor with liquid crystalline organic semiconductor, Ph BTBT 10", "venue": "", "year": 2021 }, { "abstract": "Bias stress instability has been a challenging problem and a roadblock for developing stable p type organic field effect transistors (OFETs) This device instability is hypothesized as due to electron correlated charge carrier trapping, neutralization and recombination at semiconductor/dielectric interfaces and in semiconductor channels. Here in this paper a strategy is demonstrated to improve the bias stress stability by constructing multi layered drain electrode with energy level modification layers (ELMLs) Several organic small molecules with high LUMO energy levels are experimented as ELMLs. The energy level offset between the Fermi level of the drain electrode and the LUMOs of the ELMLs are shown to construct interfacial barrier, which suppresses electron injection from the drain electrode into the channel leading to significantly improved bias stress stability of OFETs. The mechanism of the ELMLs on the bias stress stability is studied by quantitative modeling analysis of charge carrier dynamics. Of all injection models evaluated, it is found that Fowler Nordheim tunneling describes best the observed experimental data. Both theory and experimental data show that, by using the ELMLs with higher LUMO levels, the electron injection can be suppressed effectively and the bias stress stability of p type OFETs can thereby be improved significantly.", "author_names": [ "Zhenxin Yang", "Chunhua Guo", "Changsheng Shi", "Deng-Ke Wang", "Tao Zhang", "Qiang Zhu", "Zhenghong Lu" ], "corpus_id": 221347995, "doc_id": "221347995", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Improving Bias Stress Stability of p Type Organic Field Effect Transistors by Constructing Electron Injection Barrier at the Drain Electrode/Semiconductor Interfaces.", "venue": "ACS applied materials interfaces", "year": 2020 }, { "abstract": "Photosynthetic biohybrid systems have emerged as a promising platform for solar to chemical conversion by integrating excellent light harvesting ability of semiconductors with the synthetic capability of biological cells. How to enhance the utilization of solar energy, hole/electron separation efficiency and the electron transfer between the semiconductor and biological cells is crucial to develop high performance photosynthesis platforms. In this work, we developed an organic semiconductor bacteria biohybrid photosynthetic system, which could efficiently realize CO 2 reduction to produce acetic acid through non photosynthetic bacteria Moorella thermoacetica As the photosensitizers, both cationic electron transporting n type) perylene diimide derivative (PDI) and hole transporting p type) poly(fluorene co phenylene) (PFP) were coated on the bacteria surface to form p n heterojunction (PFP/PDI) layer, affording higher hole/electron separation efficiency. The p conjugated semiconductors possess excellent light harvesting ability and biocompatibility, and more importantly, the cationic side chains of organic semiconductors could intercalate into cell membrane, ensuring the efficient electron transfer to bacteria. As a result, Moorella thermoacetica can harvest photoexcited electrons from the PFP/PDI heterojunction, which can drive the Wood Ljungdahl pathway to synthesize acetic acid from CO 2 under illumination. The efficiency of this organic biohybrid is 1.6% which is comparable to those of reported inorganic biohybrid systems. This work opens a new avenue to explore bioenergy application of organic semiconductors, and also provides a convenient biomanufacturing approach to design organic semiconductor bacteria biohybrids for efficient solar to chemical conversion.", "author_names": [ "Panpan Gai", "Ruilian Qi", "Libing Liu", "Fengting Lv", "Shu Wang" ], "corpus_id": 211136633, "doc_id": "211136633", "n_citations": 19, "n_key_citations": 0, "score": 0, "title": "Solar Powered Organic Semiconductor Bacteria Biohybrids for CO2 Reduction into Acetic Acid.", "venue": "Angewandte Chemie", "year": 2020 }, { "abstract": "We report the synthesis of 1,4 dicarbonyl compounds and substituted alkenes (Mizoroki Heck type coupling) starting from secondary and tertiary alkyl halides and vinyl acetate or styrene derivatives using visible light photocatalysis. The protocol uses mesoporous graphitic carbon nitride (mpg CN) as a heterogeneous organic semiconductor photocatalyst and Ni(II) salts as Lewis acid catalysts. Detailed post characterization of the heterogeneous material has been carried out to support the proposed catalytic cycle. Apart from high functional group tolerance, mild reaction conditions, scalability as well as easy recovery and reuse of the mpg CN photocatalyst provide a practical solution to these widespread transformations in terms of sustainability and efficiency and this methodology is recommended for applications in academic and industrial synthesis.", "author_names": [ "Jagadish Khamrai", "Saikat Das", "Aleksandr Savateev", "Markus Antonietti", "Burkhard Konig" ], "corpus_id": 233834834, "doc_id": "233834834", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Mizoroki Heck type reactions and synthesis of 1,4 dicarbonyl compounds by heterogeneous organic semiconductor photocatalysis", "venue": "", "year": 2021 }, { "abstract": "Organic semiconductors (OSCs) materials are currently under intense investigation because of their potential applications such as organic field effect transistors, organic photovoltaic devices, and organic light emitting diodes. Inspired by the selenization strategy can promote anisotropic charge carrier migration, and selenium containing compounds have been proved to be promising materials as OSCs both for hole and electron transfer. Herein, we now explore the anisotropic transport properties of the series of selenium containing compounds. For the compound containing SeSe bond, the SeSe bond will break when attaching an electron, thus those compounds cannot act as n type OSCs. About the different isomer compounds with conjugated structure, the charge transfer will be affected by the stacking of the conjugated structures. The analysis of chemical structure and charge transfer property indicates that Se containing materials are promising high performance OSCs and might be used as p type, n type, or ambipolar OSCs. Furthermore, the symmetry of the selenium containing OSCs will affect the type of OSCs. In addition, there is no direct relationship between the R groups with their performance, whether it or not as p type OSCs or n types. This work demonstrates the relationship between the optoelectronic function and structure of selenium containing OSCs materials and hence paves the way to design and improve optoelectronic function of OSCs materials.", "author_names": [ "Daoyuan Zheng", "Yurong Guo", "Mingxing Zhang", "Xia Feng", "Lina Zhu", "Lijuan Qiu", "Xiaoning Jin", "Guangjiu Zhao" ], "corpus_id": 210149642, "doc_id": "210149642", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Anisotropic charge carrier transport of optoelectronic functional selenium containing organic semiconductor materials", "venue": "J. Comput. Chem.", "year": 2020 }, { "abstract": "A kind of continuous flexible paper substrate thin film transistors (TFTs) of the ratio of a controllable length to width nickel (Ni) two dimensionally connected metal organic frameworks, Ni TCNQ (TCNQ 7, 7, 8, 8 tetracyanoquinodimethane) has been prepared skillfully by using all ink jet printing Ni(NO3)2*6H2O and the TCNQ hydrothermal interface in situ reaction method. The structure analysis of Ni TCNQ on copper electrodes was revealed by combining transmission electron microscope and powder x ray diffraction techniques, indicating that it has a lamellar and porous structure. The morphology and structure of the transistor channel are stacked up by nanosheets of 2D lattice of [Ni(C12H4N4)2]n, which is further verified by scanning electron microscope, FT IR, and x ray photoelectron spectroscopy. I V characteristics show that electrical behaviors of the p type junctionless TFT are fabricated at room temperature.", "author_names": [ "Zhi-Pei Jiang", "Caihong Li", "Hezhuang Liu", "Jihua Zou", "Zhaoquan Xu", "Jiang Wu", "Zhiming M Wang" ], "corpus_id": 225330900, "doc_id": "225330900", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Signature of p type semiconductor features in paper based back gate metal organic framework thin film transistors", "venue": "", "year": 2020 }, { "abstract": "Abstract The isolation of graphene on an insulating substrate has provided new opportunities for the fabrication of electronic devices with radically new geometries and structures. The use of single layer graphene as an electrode has enabled the development of novel electronic device architectures that exploit the unique atomically thin structure of the material, which also includes a low density of states at its charge neutrality point. In this work, we present the first example of a vertical Schottky junction photodiode based on the graphene organic semiconductor metal heterostructure. The n type N,N' dioctyl 3,4,9,10 perylenedicarboximide (PTCDI C8) organic semiconductor was thermally deposited onto chemical vapor deposition (CVD) grown single layer graphene. The tunable Schottky injection barrier permitted tuning of the diode rectification ratio by more than two orders of magnitude upon application of gate biases, which increased the photocurrent but suppressed the dark current of the photodiodes. Tuning of the photovoltaic properties of the devices was also confirmed, indicating that the device architecture based on the work function tunability of graphene could provide a versatile strategy for enhancing the performance of organic photodiodes.", "author_names": [ "Young-jin Choi", "Hwi Je Woo", "Seongchan Kim", "Jia Sun", "Moon-Sung Kang", "Young Jae Song", "Jeong Ho Cho" ], "corpus_id": 219920622, "doc_id": "219920622", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Schottky junction photodiode based on graphene organic semiconductor heterostructure", "venue": "", "year": 2020 } ]
Perovskite light-emitting diode, Low starting voltage
[ { "abstract": "Hybrid perovskite semiconductors represent a promising platform for color tunable light emitting diodes (LEDs) and lasers; however, the behavior of these materials under the intense electrical excitation required for electrically pumped lasing remains unexplored. Here, we investigate methylammonium lead iodide based perovskite LEDs under short pulsed drive at current densities up to 620 A cm 2. At low current density (J 10 A cm 2) we find that the external quantum efficiency (EQE) depends strongly on the time averaged history of the pulse train and show that this curiosity is associated with slow ion movement that changes the internal field distribution and trap density in the device. The impact of ions is less pronounced in the high current density regime (J 10 A cm 2) where EQE roll off is dominated by a combination of Joule heating and charge imbalance yet shows no evidence of Auger loss, suggesting that operation at kA cm 2 current densities relevant for a laser diode should be within reach.Hybrid perovskite semiconductors are promising for wavelength tunable laser diodes but their behavior under intense electrical excitation remains unexplored. Kim et al. investigate perovskite light emitting diodes at current densities nearing 1 kA cm 2 and suggest that a laser diode is within reach.", "author_names": [ "Hoyeon Kim", "Lianfeng Zhao", "Jared Scott Price", "Alex J Grede", "Kwang Chul Roh", "Alyssa N Brigeman", "Mike Lopez", "Barry P Rand", "Noel C Giebink" ], "corpus_id": 53713589, "doc_id": "53713589", "n_citations": 72, "n_key_citations": 2, "score": 1, "title": "Hybrid perovskite light emitting diodes under intense electrical excitation", "venue": "Nature Communications", "year": 2018 }, { "abstract": "Lead halide perovskite quantum dots (LHP QDs) exhibit great potential in the backlighting display of light emitting diode applications. Light emitting backlighting with high brightness, low cost, a.", "author_names": [ "Xicheng Wang", "Zhen Bao", "Yu-Chun Chang", "Ru-Shi Liu" ], "corpus_id": 225116686, "doc_id": "225116686", "n_citations": 17, "n_key_citations": 0, "score": 1, "title": "Perovskite Quantum Dots for Application in High Color Gamut Backlighting Display of Light Emitting Diodes", "venue": "", "year": 2020 }, { "abstract": "This is the first report of an investigation on flexible perovskite solar cells for artificial light harvesting by using a white light emitting diode (LED) lamp as a light source at 200 and 400 lx, values typically found in indoor environments. Flexible cells were developed using either low temperature sol gel or atomic layer deposited compact layers over conducting polyethylene terephthalate (PET) substrates, together with ultraviolet (UV) irradiated nanoparticle TiO2 scaffolds, a CH3NH3PbI3 xClx perovskite semiconductor, and a spiro MeOTAD hole transport layer. By guaranteeing high quality carrier blocking (via the 10 40 nm thick compact layer) and injection (via the nanocrystalline scaffold and perovskite layers) behavior, maximum power conversion efficiencies (PCE) and power densities of 10.8% and 7.2 mW*cm 2, respectively, at 200 lx, and 12.1% and 16.0 mW*cm 2, respectively, at 400 lx were achieved. These values are the state of the art, comparable to and even exceeding those of flexible dye sensitized solar cells under LED lighting, and significantly greater than those for flexible amorphous silicon, which are currently the main flexible photovoltaic technologies commercially considered for indoor applications. Furthermore, there are significant margins of improvement for reaching the best levels of efficiency for rigid glass based counterparts, which we found was a high of PCE ~24% at 400 lx. With respect to rigid devices, flexibility brings the advantages of being low cost, lightweight, very thin, and conformal, which is especially important for seamless integration in indoor environments.", "author_names": [ "Giulia Lucarelli", "Francesco Di Giacomo", "Valerio Zardetto", "Mariadriana Creatore", "Thomas M Brown" ], "corpus_id": 136230737, "doc_id": "136230737", "n_citations": 58, "n_key_citations": 2, "score": 1, "title": "Efficient light harvesting from flexible perovskite solar cells under indoor white light emitting diode illumination", "venue": "Nano Research", "year": 2017 }, { "abstract": "In this study, a dual source vapor evaporation method was employed to fabricate the high quality CsPbBr3 thin films with a good crystalline and high surface coverage. Temperature dependent and excitation power dependent photoluminescence measurements were performed to study the optical properties of the CsPbBr3 material. Further, based on the experimental data, the temperature sensitivity coefficient of band gap and exciton binding energy were estimated. More importantly, for the first time, we designed and prepared a hole injection layer free perovskite light emitting diode (LED) based on the Au/MgO/CsPbBr3/n MgZnO/n+ GaN structure, producing an intense green emission ~538 nm) with a high purity. Besides, the device demonstrated a high luminance of 5025 cd/m2, an external quantum efficiency of 1.46% a current efficiency of 1.92 cd/A, and a power efficiency of 1.76 lm/W. We studied in detail the current voltage and electroluminescence properties of the prepared device and proposed the hole generation models and the carrier transport/recombination mechanisms to make these interesting characteristics certain. The results obtained would provide a new and effective strategy for the design and preparation of perovskite LEDs.", "author_names": [ "Zhifeng Shi", "Lingzhi Lei", "Yunfeng Li", "Fei Zhang", "Zhuang-zhuang Ma", "Xinjian Li", "Di Wu", "Tingting Xu", "Yongtao Tian", "Bao-lin Zhang", "Zhiqiang Yao", "Guotong Du" ], "corpus_id": 206486491, "doc_id": "206486491", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "Hole Injection Layer Free Perovskite Light Emitting Diodes.", "venue": "ACS applied materials interfaces", "year": 2018 }, { "abstract": "All inorganic perovskite light emitting diode (PeLED) has a high stability in ambient atmosphere, but it is a big challenge to achieve high performance of the device. Basically, device design, control of energy level alignment, and reducing the energy barrier between adjacent layers in the architecture of PeLED are important factors to achieve high efficiency. In this study, we report a CsPbBr3 based PeLED with an inverted architecture using lithium doped TiO2 nanoparticles as the electron transport layer (ETL) The optimal lithium doping balances the charge carrier injection between the hole transport layer and ETL, leading to superior device performance. The device exhibits a current efficiency of 3 cd A 1, a luminance efficiency of 2210 cd m 2, and a low turn on voltage of 2.3 V. The turn on voltage is one of the lowest values among reported CsPbBr3 based PeLEDs. A 7 fold increase in device efficiencies has been obtained for lithium doped TiO2 compared to that for undoped TiO2 based devices.", "author_names": [ "Alagesan Subramanian", "Zhenghui Pan", "Zhenbo Zhang", "Imtiaz Ahmad", "Jing Chen", "Meinan Liu", "Shuang Cheng", "Yijun Xu", "Jingjing Wu", "Wei Lei", "Qasim Khan", "Yuegang Zhang" ], "corpus_id": 4643323, "doc_id": "4643323", "n_citations": 28, "n_key_citations": 0, "score": 0, "title": "Interfacial Energy Level Alignment for High Performance All Inorganic Perovskite CsPbBr3 Quantum Dot Based Inverted Light Emitting Diodes.", "venue": "ACS applied materials interfaces", "year": 2018 }, { "abstract": "Abstract The traditional hot injection (HI) process needs high temperature, inert gas protection, and localized injection operation, which severely hinder their large scale industrialization. Moreover, the CsPb1 xSnxBr3 HI QDs exhibit poor stability. Herein, we report the room temperature (RT) synthesis of CsPb1 xSnxBr3 perovskite QDs by modified ligand assisted reprecipitation (LARP) approach. Compared with the CsPb1 xSnxBr3 HI QDs reported in literatures, the CsPb1 xSnxBr3 RT QDs show higher photoluminescence quantum yield (PLQY) and better stability: the CsPb0.9Sn0.1Br3 RT QDs obtain the highest PLQY of more than 91% and the stability of the film made with this QDs still maintain more than 80% of its original fluorescence strength after 120 days in air environment. Because of the superior PLQY, light emitting diodes (LEDs) based on the RT QDs is constructed, and it exhibits an external quantum efficiency (EQE) of 1.8% a luminance of 1600 cdm 2, a current efficiency of 4.89 cdA 1, a power efficiency of 6.41 lmw 1, and a low on voltage of 3.6 V. The present work provides a feasible method for large scale industrial synthesis of perovskite QDs at room temperature and shows that the CsPb1 xSnxBr3 RT QDs are promising for highly efficient LEDs.", "author_names": [ "Jidong Deng", "Haoran Wang", "Jiao Xun", "Jingxi Wang", "Xuyong Yang", "Wei Shen", "Ming Li", "Rongxing He" ], "corpus_id": 210517327, "doc_id": "210517327", "n_citations": 11, "n_key_citations": 0, "score": 1, "title": "Room temperature synthesis of excellent performance CsPb1 Sn Br3 perovskite quantum dots and application in light emitting diodes", "venue": "", "year": 2020 }, { "abstract": "Halide perovskite multiple quantum wells (MQWs) have recently shown great potential in the field of light emitting diodes. We report a facile solution based approach to fabricate dimensionality tunable perovskite MQWs by introducing 1 naphthylmethylammonium (NMA) cations into CsPbI3 perovskites. Through the dimensional tailoring of (NMA)2Csn 1PbnI3n+1 perovskite MQWs, the crystallinity and photoluminescence quantum efficiencies (PLQEs) are significantly improved. We have obtained high performance red perovskite light emitting diodes (PeLEDs) with a luminance of 732 cd m 2 and a maximum external quantum efficiency of 7.3% which are among the best performing red PeLEDs. Significantly, the maximum luminance of our PeLEDs is obtained at a low applied voltage of 3.4 V, with a turn on voltage close to the perovskite band gap (Vturn on 1.9 V) These outstanding performance characteristics demonstrate that dimensional tailoring of perovskite MQWs is a feasible and effective strategy to achieve high performance PeLEDs, which is attractive for full color display applications of perovskites.", "author_names": [ "Jin Chang", "Shuting Zhang", "Nana Wang", "Yan Sun", "Yingqiang Wei", "Renzhi Li", "Chang Yi", "Jianpu Wang", "Wei Huang" ], "corpus_id": 3776081, "doc_id": "3776081", "n_citations": 61, "n_key_citations": 1, "score": 1, "title": "Enhanced Performance of Red Perovskite Light Emitting Diodes through the Dimensional Tailoring of Perovskite Multiple Quantum Wells.", "venue": "The journal of physical chemistry letters", "year": 2018 }, { "abstract": "Organometal halide perovskites (OHPs) have become the most promising optoelectronic material in the past few years with a myriad of applications in the photovoltaic, light emitting, and laser fields. However, for light emitting applications, the low photoluminescence quantum yield (PLQY) of OHP film is critical to hinder the efficiency improvement of OHP film based light emitting diodes (PeLEDs) Herein, we study the effects of rubidium incorporation on the crystal growth, structure, and photoelectric and optical properties of formamidinium lead bromide based (FAPbBr3 based) perovskite films and light emission performance of PeLEDs. It is found that rubidium incorporation can significantly enhance the PLQY of FAPbBr3 film by suppressing the trap density and thus improve the withstand voltage as well as the performance of PeLEDs. When FAPbBr3 film with optimal Rb doping ratio is employed as the light emitter of PeLEDs, the maximum luminance and current efficiency is enhanced by ~10 fold and ~5 fold to 66 353 cd/m2 and 24.22 cd/A compared to the controlled device, respectively, the record performance based on FAPbBr3 PeLEDs so far. The enhanced performance can be chiefly attributed to the increase of PLQY and decrease of trap defect density of perovskite film with rubidium incorporation. Our research is expected to stimulate the development of OHPs for the next generation lighting and display fields.", "author_names": [ "Yifei Shi", "Jun Xi", "Ting Lei", "Fang Yuan", "Jinfei Dai", "Chenxin Ran", "Hua Dong", "Bo Jiao", "Xun Hou", "Zhaoxin Wu" ], "corpus_id": 206480880, "doc_id": "206480880", "n_citations": 40, "n_key_citations": 0, "score": 1, "title": "Rubidium Doping for Enhanced Performance of Highly Efficient Formamidinium Based Perovskite Light Emitting Diodes.", "venue": "ACS applied materials interfaces", "year": 2018 }, { "abstract": "Perovskite light emitting diode (PeLED) has been vigorously developed in recent years. As it has demonstrated well performance on the rigid substrates, the next important direction of PeLED is their integration with stretchable components to realize stretchable, responsive device. Here, we describe a facile fabrication of stretchable perovskite light emissive touch responsive devices (PeLETDs) through utilizing highly transparent and conductive polyurethane/silver nanowires (PU/AgNWs) as the electrode. Meanwhile, a stretchable tri composite perovskite emissive layer was developed by blending a small amount of poly(ethylene oxide) (PEO) and polyvinylpyrrolidone (PVP) with CsPbBr3. Additionally, a thin PVP layer was introduced at the bottom side of the emissive layer. On one hand, it can further improve the morphology of the emissive layer; on the other hand, it can serve as an electron injection barrier to reduce the high non radiative recombination at the corresponding interface. Further, to fulfill the responsive function of the fabricated PeLEDs, a poly(ethylene terephthalate) (PET) spacer with a 100 mm thickness was inserted between the top electrode and the emissive layer. A stretchable PeLETD is finally demonstrated to possess a low turn on voltage of 2 V with a brightness of 380.5 cd m 2 at 7.5 V, and can sustain 30% uniaxial strain with a small luminance variation of 24% More intriguingly, our stretchable PeLETD exhibited high stability, which could be well touch responsibility, where the luminance is on/off switched for 300 cycles by the repeated pressure.", "author_names": [ "Dai-Hua Jiang", "Yi-Chun Liao", "Chia-Jung Cho", "Loganathan Veeramuthu", "Fang-Cheng Liang", "Ting-Chieh Wang", "Chu-Chen Chueh", "Toshifumi Satoh", "Shih-Huang Tung" ], "corpus_id": 211726036, "doc_id": "211726036", "n_citations": 13, "n_key_citations": 1, "score": 1, "title": "Facile Fabrication of Stretchable Touch Responsive Perovskite Light Emitting Diodes through Using Robust Stretchable Composite Electrodes.", "venue": "ACS applied materials interfaces", "year": 2020 }, { "abstract": "Although all inorganic perovskite light emitting diodes (PeLED) have satisfactory stability under an ambient atmosphere, producing devices with high performance is challenging. A device architecture with a reduced energy barrier between adjacent layers and optimized energy level alignment in the PeLED is critical to achieve high electroluminescence efficiency. In this study, we report the optimization of a CsPbBr3 based PeLED device structure with Li doped TiO2 nanoparticles as the electron transport layer (ETL) Optimal Li doping balances charge carrier injection between the hole transport layer (HTL) and ETL, leading to superior performance in both devices. The turn on voltages for devices with Li doped TiO2 nanoparticles were significantly reduced from 7.7 V to 4.9 V and from 3 V to 2 V in the direct and inverted PeLED structures, respectively. The low turn on voltage for green emission is one of the lowest values among the reported CsPbBr3 based PeLEDs. Further investigations show that the device with an inverted structure is superior to the device with a direct structure because the energy barrier for carrier injection was minimized. The inverted structure devices exhibited a current efficiency of 5.6 cd A 1 for the pristine TiO2 ETL, while it was 15.2 cd A 1 for the Li doped TiO2 ETL, a factor of ~2.7 enhancement at 5000 cd m 2.", "author_names": [ "Qasim Khan", "Alagesan Subramanian", "Guannan Yu", "Khan Maaz", "Delong Li", "Rizwan Ur Rehman Sagar", "Keqiang Chen", "Wei Lei", "Babar Shabbir", "Yupeng Zhang" ], "corpus_id": 73470179, "doc_id": "73470179", "n_citations": 25, "n_key_citations": 0, "score": 1, "title": "Structure optimization of perovskite quantum dot light emitting diodes.", "venue": "Nanoscale", "year": 2019 } ]
machine learning and parallel computing
[ { "abstract": "Tremendous progress has been witnessed in artificial intelligence within the domain of neural network backed deep learning systems and its applications. As we approach the post Moore's Law era, the limit of semiconductor fabrication technology along with a rapid increase in data generation rates have lead to an impending growing challenge of tackling newer and more modern machine learning problems. In parallel, quantum computing has exhibited rapid development in recent years. Due to the potential of a quantum speedup, quantum based learning applications have become an area of significant interest, in hopes that we can leverage quantum systems to solve classical problems. In this work, we propose a quantum deep learning architecture; we demonstrate our quantum neural network architecture on tasks ranging from binary and multi class classification to generative modelling. Powered by a modified quantum differentiation function along with a hybrid quantum classic design, our architecture encodes the data with a reduced number of qubits and generates a quantum circuit, loading it onto a quantum platform where the model learns the optimal states iteratively. We conduct intensive experiments on both the local computing environment and IBM Q quantum platform. The evaluation results demonstrate that our architecture is able to outperform Tensorflow Quantum by up to 12.51% and 11.71% for a comparable classic deep neural network on the task of classification trained with the same network settings. Furthermore, our GAN architecture runs the discriminator and the generator purely on quantum hardware and utilizes the swap test on qubits to calculate the values of loss functions. In comparing our quantum GAN, we note our architecture is able to achieve similar performance with 98.5% reduction on the parameter set when compared to classical GANs. With the same number of parameters, additionally, QuGAN outperforms other quantum based GANs in the literature for up to 125.0% in terms of similarity between generated distributions and original data sets. Keywords Quantum Machine Learning; Quantum Deep Learning; Quantum Generative Adversarial Networks; Quantum State Fidelity Preprints (www.preprints.org) NOT PEER REVIEWED Posted: 24 March 2021 doi:10.20944/preprints202103.0583.v1", "author_names": [ "Samuel A Stein" ], "corpus_id": 233638067, "doc_id": "233638067", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Quantum Computing Aided Machine Learning Through Quantum State Fidelity", "venue": "", "year": 2021 }, { "abstract": "As the training dataset size and the model size of machine learning increase rapidly, more computing resources are consumed to speedup the training process. However, the scalability and performance reproducibility of parallel machine learning training, which mainly uses stochastic optimization algorithms, are limited. In this paper, we demonstrate that the sample difference in the dataset plays a prominent role in the scalability of parallel machine learning algorithms. We propose to use statistical properties of dataset to measure sample differences. These properties include the variance of sample features, sample sparsity, sample diversity, and similarity in sampling sequences. We choose four types of parallel training algorithms as our research objects: (1) the asynchronous parallel SGD algorithm (Hogwild! algorithm) (2) the parallel model average SGD algorithm (minibatch SGD algorithm) (3) the decentralization optimization algorithm, and (4) the dual coordinate optimization (DADM algorithm) Our results show that the statistical properties of training datasets determine the scalability upper bound of these parallel training algorithms.", "author_names": [ "Daning Cheng", "Shigang Li", "Hanping Zhang", "Fen Xia", "Yunquan Zhang" ], "corpus_id": 232043263, "doc_id": "232043263", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Why Dataset Properties Bound the Scalability of Parallel Machine Learning Training Algorithms", "venue": "IEEE Transactions on Parallel and Distributed Systems", "year": 2021 }, { "abstract": "This special issue of Concurrency and Computation: Practice and Experience comprises four papers extending the original workshop publications accepted and presented at MPP 2019 (8th Workshop on Parallel Programming Models Special Issue on IoT and Machine Learning) held in Rio de Janeiro in conjunction with IPDPS 2019. The papers represent interesting research ideas of parallel programming models, tools, and optimizations suited for being applied to IoT based applications. The paper titled \"Enabling Heterogeneous Ray Tracing Acceleration in Edge/Cloud Architectures\" represents a very interesting research on reconfigurable accelerators for Ray Tracing, specialized in computing ray triangle intersections at the network edge of a heterogeneous cloud computing environment. The authors validated their approach on the Xilinx Zynq FPGA platform. The paper titled \"An Incremental Reinforcement Learning Scheduling Strategy for Data Intensive Scientific Workflows in the Cloud\" is a research work proposing a new scheduling algorithm based on Reinforcement Learning for scientific workflows on HPC distributed resources and Clouds. The paper titled \"Latency aware Adaptive Micro Batching Techniques for Streamed Data Compression on GPUs\" proposes a set of Autonomic Computing strategies for configuring the optimal parallelism degree and batch size on streaming data compression parallel applications on GPU architectures. Finally, the paper titled \"Gamma General Abstract Model for Multiset mAnipulation and Dynamic Dataflow Model: an Equivalence Study\" is an interesting research study on new applications of the Gamma Model (General Abstract Model for Multiset mAnipulation) and its joint utilization with the Dataflow programming model. As Guest Editors, we would like to express our gratitude for the valuable contributions made by all authors. We would like to thank all the reviewers who helped us during the thorough review process based on several review rounds. Finally, we would like to thank all the editorial board members and all staff of Concurrency and Computation: Practice and Experience for allowing us to publish our Special Issue and for their invaluable support during the whole publication process.", "author_names": [ "Cristiana Barbosa Bentes", "Felipe Maia Galvao Franca", "Leandro Augusto Justen Marzulo", "Gabriele Mencagli", "Mauricio Lima Pilla" ], "corpus_id": 233964655, "doc_id": "233964655", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Novel parallel processing techniques for IoT based machine learning applications", "venue": "Concurr. Comput. Pract. Exp.", "year": 2021 }, { "abstract": "Forecasting the dynamics of large complex networks from previous time series data is important in a wide range of contexts. Here we present a machine learning scheme for this task using a parallel architecture that mimics the topology of the network of interest. We demonstrate the utility and scalability of our method implemented using reservoir computing on a chaotic network of oscillators. Two levels of prior knowledge are considered: (i) the network links are known; and (ii) the network links are unknown and inferred via a data driven approach to approximately optimize prediction.", "author_names": [ "Keshav Srinivasan", "Nolan J Coble", "Joyce L Hamlin", "Thomas M Antonsen", "Edward Ott", "Michelle Girvan" ], "corpus_id": 237346805, "doc_id": "237346805", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Parallel Machine Learning for Forecasting the Dynamics of Complex Networks", "venue": "ArXiv", "year": 2021 }, { "abstract": "We observe a continuously increased use of Deep Learning (DL) as a specific type of Machine Learning (ML) for data intensive problems (i.e. 'big data' that requires powerful computing resources with equally increasing performance. Consequently, innovative heterogeneous High Performance Computing (HPC) systems based on multi core CPUs and many core GPUs require an architectural design that addresses end user communities' requirements that take advantage of ML and DL. Still the workloads of end user communities of the simulation sciences (e.g. using numerical methods based on known physical laws) needs to be equally supported in those architectures. This paper offers insights into the Modular Supercomputer Architecture (MSA) developed in the Dynamic Exascale Entry Platform (DEEP) series of projects to address the requirements of both simulation sciences and data intensive sciences such as High Performance Data Analytics (HPDA) It shares insights into implementing the MSA in the Julich Supercomputing Centre (JSC) hosting Europe No. 1 Supercomputer Julich Wizard for European Leadership Science (JUWELS) We augment the technical findings with experience and lessons learned from two application communities case studies (i.e. remote sensing and health sciences) using the MSA with JUWELS and the DEEP systems in practice. Thus, the paper provides details into specific MSA design elements that enable significant performance improvements of ML and DL algorithms. While this paper focuses on MSA based HPC systems and application experience, we are not losing sight of advances in Cloud Computing (CC) and Quantum Computing (QC) relevant for ML and DL.", "author_names": [ "Morris Riedel", "Rocco Sedona", "Chadi Barakat", "Petur Einarsson", "Reza Hassanian", "Gabriele Cavallaro", "Matthias Book", "Helmut Neukirchen", "Andreas Lintermann" ], "corpus_id": 235639155, "doc_id": "235639155", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Practice and Experience in using Parallel and Scalable Machine Learning with Heterogenous Modular Supercomputing Architectures", "venue": "2021 IEEE International Parallel and Distributed Processing Symposium Workshops (IPDPSW)", "year": 2021 }, { "abstract": "Today's systems, especially in the age of federated learning, rely on sending all the data to the cloud, and then use complex algorithms, such as Deep Neural Networks, which require billions of parameters and many hours to train a model. In contrast, the human brain can do much of this learning effortlessly. Hyperdimensional (HD) Computing aims to mimic the behavior of the human brain by utilizing high dimensional representations. This leads to various desirable properties that other Machine Learning (ML) algorithms lack such as: robustness to noise in the system and simple, highly parallel operations. In this paper, we propose HyDREA, a HD computing system that is Robust, Efficient, and Accurate. To evaluate the feasibility of HyDREA in a federated learning environment with wireless communication noise, we utilize NS 3, a popular network simulator that models a real world environment with wireless communication noise. We found that HyDREA is 48x more robust to noise than other comparable ML algorithms. We additionally propose a Processing in Memory (PIM) architecture that adaptively changes the bitwidth of the model based on the signal to noise ratio (SNR) of the incoming sample to maintain the robustness of the HD model while achieving high accuracy and energy efficiency. Our results indicate that our proposed system loses less than 1% classification accuracy, even in scenarios with an SNR of 6.64. Our PIM architecture is also able to achieve 255x better energy efficiency and speed up execution time by 28x compared to the baseline PIM architecture.", "author_names": [ "Justin Morris", "Kazim Ergun", "Behnam Khaleghi", "Mohsen Imani", "Baris Aksanli", "Tajana Simunic" ], "corpus_id": 232054454, "doc_id": "232054454", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "HyDREA: Towards More Robust and Efficient Machine Learning Systems with Hyperdimensional Computing", "venue": "2021 Design, Automation Test in Europe Conference Exhibition (DATE)", "year": 2021 }, { "abstract": "Elastic scaling in/out of operator parallelism degree is needed for processing real time dynamic data streams under low latency and high stability requirements. Usually the operator parallelism degree is set when a streaming application is submitted to a stream computing system and kept intact during runtime. This may substantially affect the performance of the system due to the fluctuation of input streams and availability of system resources. To address the problems brought by the static parallelism setting, we propose and implement a machine learning based elastic strategy for operator parallelism (named MeStream) in big data stream computing systems. The architecture of Me Stream and its key models are introduced, including parallel bottleneck identification, parameter plan generation, parameter migration and conversion, and instances scheduling. Metrics of execution latency and process latency of the proposed scheduling strategy are evaluated on the widely used big data stream computing system Apache Storm. The experimental results demonstrate the efficiency and effectiveness of the proposed strategy.", "author_names": [ "Dawei Sun", "Rajkumar Buyya" ], "corpus_id": 237056513, "doc_id": "237056513", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "A Machine Learning based Elastic Strategy for Operator Parallelism in a Big Data Stream Computing System", "venue": "", "year": 2021 }, { "abstract": "We present a CMOS imager for low latency face detection empowered by parallel imaging and computing of machine learning (ML) classifiers. The energy efficient parallel operation and multi scale detection eliminate image capture delay and significantly alleviate backend computational loads. The proposed pixel architecture, composed of dynamic samplers in a global shutter (GS) pixel array, allows for energy efficient in memory charge domain computing of feature extraction and classification. The illumination invariant detection was realized by using log Haar features. A prototype 240x240 imager achieved an on chip face detection latency of 5.1ms with a 97.9% true positive rate and 2% false positive rate at 120fps. Moreover, a dynamic nature of in memory computing allows an energy efficiency of 419pJ/pixel for feature extraction and classification, leading to the smallest latency energy product of 3.66msnJ/pixel with digital backend processing.", "author_names": [ "Juan Salinas", "Euisik Yoon" ], "corpus_id": 236980967, "doc_id": "236980967", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A5.1ms Low Latency Face Detection Imager with In Memory Charge Domain Computing of Machine Learning Classifiers", "venue": "2021 Symposium on VLSI Technology", "year": 2021 }, { "abstract": "We present a CMOS imager for low latency face detection empowered by parallel imaging and computing of machine learning (ML) classifiers. The energy efficient parallel operation and multi scale detection eliminate image capture delay and significantly alleviate backend computational loads. The proposed pixel architecture, composed of dynamic samplers in a global shutter (GS) pixel array, allows for energy efficient in memory charge domain computing of feature extraction and classification. The illumination invariant detection was realized by using log Haar features. A prototype 240x240 imager achieved an on chip face detection latency of 5.1ms with a 97.9% true positive rate and 2% false positive rate at 120fps. Moreover, a dynamic nature of in memory computing allows an energy efficiency of 419pJ/pixel for feature extraction and classification, leading to the smallest latency energy product of 3.66msnJ/pixel with digital backend processing.", "author_names": [ "Hyunsoo Song", "Sungjin Oh", "Juan Salinas", "Euisik Yoon" ], "corpus_id": 236480416, "doc_id": "236480416", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A 5.1ms Low Latency Face Detection Imager with In Memory Charge Domain Computing of Machine Learning Classifiers", "venue": "2021 Symposium on VLSI Circuits", "year": 2021 }, { "abstract": "To detect defect is an important concept in machine leaning techniques and ambiguous dataset which develops into a challenging issue, as the software product expands in terms of size and its complexity. This chapter reveals an applied novel multi learner model which is ensembled to predict software metrics using classification algorithms and propose algorithm applied in parallel method for detection on ambiguous data using density sampling and develop an implementation running on both GPUs and multi core CPUs. The defect on the NASA PROMISE defect dataset is adequately predicted and classified using these models and implementing GPU computing. The performance compared to the traditional learning models improved algorithm and parallel implementation on GPUs shows less processing time in ensemble model compared to decision tree algorithm and effectively optimizes the true positive rate.", "author_names": [ "Sivakumar S", "Sreedevi E", "PremaLatha V", "Haritha D" ], "corpus_id": 228894848, "doc_id": "228894848", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Parallel Defect Detection Model on Uncertain Data for GPUs Computing by a Novel Ensemble Learning", "venue": "", "year": 2021 } ]
Bi2OS2
[ { "abstract": "Layered semiconductors with broad photoabsorption, a long carrier lifetime and high carrier mobility are of crucial importance for high performance optoelectronic and photovoltaic devices; however it is hard to satisfy these requirements simultaneously in a system due to the opposite dependence on the layer thickness. Herein, by means of ab initio time domain nonadiabatic molecular dynamic simulations, we find a new mechanism in Bi2OS2 nanosheets inducing an anomalous layer dependent property of carrier lifetimes, which makes the few layered Bi2OS2 a possible system for fulfilling the above requirements concurrently. It is revealed that the interlayer dipole dipole interaction in few layered Bi2OS2 effectively breaks the two fold degenerate orbitals of [BiS2] layers, which not only cuts down the overlap of the electron and hole wave functions, but also accelerates the electron decoherence process. This significantly suppresses the electron hole recombination and prolongs the photogenerated carrier lifetime of few layered Bi2OS2. The mechanism unveiled here paves a possible way for developing advanced optoelectronic and photovoltaic devices through engineering interlayer dipole dipole coupling.", "author_names": [ "Xianghong Niu", "Guangfen Wu", "Xiweng Zhang", "Jinlan Wang" ], "corpus_id": 212406558, "doc_id": "212406558", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Interlayer coupling prolonged the photogenerated carrier lifetime of few layered Bi2OS2 semiconductors.", "venue": "Nanoscale", "year": 2020 }, { "abstract": "Although polymer solar cells (PSCs) have many advantages, they have obtained great progress in the two decades, the low charge carrier mobility still restricts performance progress of PSCs. Two dimensional (2D) Bi based semiconductor nanomaterial (Bi2OS2) can be a potential material for improving the charge carrier mobility in the active layer of PSCs, because it exhibits a high carrier mobility, suitable band gap, wide absorption range, and good stability. In this work, we synthesize the 2D Bi2OS2 nanomaterial and incorporate it into active layer of PSCs as a third component for the first time. By introduction 1 wt% 2D Bi2OS2 nanomaterial into the PSCs, the power conversion efficiency (PCE) of PSCs can be obviously improved by more than 17% comparison with binary PSCs (from 10.51% to 12.31% The enhancement of PCE is mainly due to the improving of charge transport, surface morphology, and crystallization of active layer. It is worth noting that the 2D Bi2OS2 play the role of the heterogeneous nucleation in the active layer, resulting in the enhanced crystallization of PBDB T and ITIC. These results not only provide a way to improve the performance of PSCs, but also show that the 2D Bi2OS2 nanomaterial has great potential application in the PSCs.", "author_names": [ "Chengwen Huang", "Huangzhong Yu" ], "corpus_id": 214143224, "doc_id": "214143224", "n_citations": 4, "n_key_citations": 0, "score": 1, "title": "Enhanced carrier mobility and power conversion efficiency of organic solar cells by adding 2D Bi2OS2", "venue": "", "year": 2020 }, { "abstract": "Correction for 'Interlayer coupling prolonged the photogenerated carrier lifetime of few layered Bi2OS2 semiconductors' by Xianghong Niu et al. Nanoscale, 2020, 12, 6057 6063, DOI: 10.1039/D0NR00447B.", "author_names": [ "Xianghong Niu", "Guangfen Wu", "Xiweng Zhang", "Jinlan Wang" ], "corpus_id": 220429882, "doc_id": "220429882", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Correction: Interlayer coupling prolonged the photogenerated carrier lifetime of few layered Bi2OS2 semiconductors.", "venue": "Nanoscale", "year": 2020 }, { "abstract": "Abstract In this paper, three dimensional (3D) nanoripple like ZnO nanorod arrays (R ZnO NRAs) are successfully fabricated and modified by two dimensional (2D) Bi2OS2 material, and inverted polymer solar cells (IPSCs) with R ZnO modified by Bi2OS2 as electron transmission layer (ETL) are fabricated for the first time. The results show that the surface morphologies of R ZnO NRAs can be controlled by adjusting the concentration of the modified 2D Bi2OS2 solution. Bi2OS2 modification can not only suppress the surface defects of R ZnO NRAs, reduce the recombination of photogenerated charges, but also increase crystallinity of the active layer, resulting in effective electron collection. And thus, the performance of IPSCs is obviously improved. The power conversion efficiency (PCE) of PTB7: PCBM based PSCs with R ZnO NRAs modified by 2% Bi2O2S as ETL is considerably raised to 7.31% from 5.51% More interestingly, Bi2OS2 modification enhances IPSCs stability to remain 80.9% of their initial PCE after 80 days, yet IPSCs with pristine R ZnO NRAs remain only 47.4% of their initial PCE. Moreover, this approach can also successfully improve the performance of another IPSC composed of PBDB T: ITIC blends. The PCE of the device based on 2% Bi2OS2 modified R ZnO NRAs is improved to 9.94% from 8.03% of the reference device without Bi2OS2 modification. This work not only provides an effective mean of surface modification of R ZnO NRAs, but also shows the Bi2OS2 material has potential application in PSCs.", "author_names": [ "Zuping Wu", "Chengwen Huang", "Chunling Hou" ], "corpus_id": 213516025, "doc_id": "213516025", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Surface modification on nanoripple like ZnO nanorod arrays using two dimensional (2D) Bi2OS2 to fabricate high performance inverted polymer solar cells", "venue": "", "year": 2020 }, { "abstract": "Abstract Additive engineering has been proved to be an effective method to increase the performance of perovskite solar cells (PVSCs) by increasing the quality of the perovskite thin film. Two dimensional (2D) Bi2OS2 nanomaterial is an excellence optoelectronic material because of its tunable direct band gap, ultra high charge mobility, wide absorption range and high absorption coefficient. In this work, 2D Bi2OS2 nanosheets are synthesized and introduced as additives into the perovskite precursor solution to adjust the film formation process for the first time. Serving as heterogeneous nucleation site, 2D Bi2OS2 can reduce the nucleation barrier and assist the formation of highly crystalline and crystal orientation along the (1 1 0) plane perovskite thin film, which is beneficial to improve the mobility and lifetime of charge carriers. Besides, X ray photoelectron spectroscopy (XPS) measurement reveals that 2D Bi2OS2 nanosheets can interact with Pb2+ within the perovskite through Pb S bond, thus suppressing the uncoordinated Pb2+ ions trap states. Scanning electron microscope (SEM) demonstrates 2D Bi2OS2 nanosheets can fill up the pin holes and grain boundaries on the perovskite film surface. Ultraviolet photoelectron spectroscopy (UPS) measurement indicates that the valence band (VB) of optimized perovskite film is 0.28 eV upshifted closer to the highest occupied molecular orbital (HOMO) of the hole transport layer (HTL) which accelerates the charge transportation at perovskite/HTL interface. Consequently, the average power conversion efficiency (PCE) of 18.96% (highest PCE of 19.89% is achieved upon incorporating 2D Bi2OS2 nanosheets with an optimized concentration of 0.02 mg/ml into MAPbI3 precursor solution, which is greatly improved compared to the average PCE of 15.71% for the control devices (highest PCE of 16.77% Besides, the lifetime of optimized PVSCs is also prolonged due to the less defect states and better perovskite film quality. This work not only provides a facile method to increase the PCE and stability of PVSCs, but also reveals 2D Bi2OS2 material has potential applications in PVSCs.", "author_names": [ "Chen Jinyun", "Jiankai Zhang", "Chengwen Huang", "Zhuoneng Bi", "Huangzhong Yu", "Shengwei Shi", "Xueqing Xu" ], "corpus_id": 228929309, "doc_id": "228929309", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Two dimensional Bi2OS2 doping improves the performance and stability of perovskite solar cells", "venue": "", "year": 2020 }, { "abstract": "Two dimensional (2D) semiconductors with desirable band gaps and high carrier mobility are highly sought after for future application in nanoelectronics. Herein, by means of first principles calculations, we predict that a new 2D material, namely a Bi2OS2 nanosheet, possesses not only a tunable direct band gap, but also ultra high electron mobility (up to 26 570 cm2 V 1 s 1) More interestingly, an anomalous layer dependent band gap is revealed, derived from the synergetic effect of the quantum confinement and intrinsic surface electron states. 2D Bi2OS2 also exhibits excellent absorption over the entire solar spectrum and the absorption coefficient is comparable to that of inorganic organic hybrid perovskite solar cells. Moreover, the Bi2OS2 monolayer maintains good structural integrity up to 1000 K and has a relatively small exfoliation energy from its layered bulk. The excellent electronic and optical properties, together with high stability and great experimental possibility, render 2D Bi2OS2 a promising material for future nanoelectronic and optoelectronic applications.", "author_names": [ "Xiweng Zhang", "Bing Zhang Wang", "Xianghong Niu", "Yunhai Li", "Yunfei Chen", "Jinlan Wang" ], "corpus_id": 139856565, "doc_id": "139856565", "n_citations": 23, "n_key_citations": 0, "score": 1, "title": "Bi2OS2: a direct gap two dimensional semiconductor with high carrier mobility and surface electron states", "venue": "", "year": 2018 }, { "abstract": "Abstract The band gaps of isostructural Bi 2 OS 2 and LaOBiS 2 were examined using optical absorption and discussed with the band structures calculated based on the crystal structures determined using synchrotron X ray diffraction. The Bi 6p and S 3p orbitals in the Bi S plane were computationally predicted to constitute the bands near the Fermi level. The optical reflectance spectra of Bi 2 OS 2 and LaOBiS 2 showed optical band gaps of ~1.0 eV, which were close to the computationally calculated direct band gaps of ~0.8 eV. Our results show that Bi 2 OS 2 and LaOBiS 2 are semiconductors containing direct band gaps of 0.8 1.0 eV, and they are suggested to be candidates for optoelectronic materials in the near infrared region without highly toxic elements.", "author_names": [ "Akira Miura", "Yoshikazu Mizuguchi", "Takahiro Takei", "Nobuhiro Kumada", "Eisuke Magome", "Chikako Moriyoshi", "Yoshihiro Kuroiwa", "Kiyoharu Tadanaga" ], "corpus_id": 119223127, "doc_id": "119223127", "n_citations": 24, "n_key_citations": 0, "score": 1, "title": "Structures and optical absorption of Bi2OS2 and LaOBiS2", "venue": "", "year": 2016 }, { "abstract": "The band gaps of isostructural Bi2OS2 and LaOBiS2 were examined using optical absorption and discussed with the band structures calculated based on the crystal structures determined using synchrotron X ray diffraction. The Bi 6p and S 3p orbitals in the Bi S plane were computationally predicted to constitute the bands near the Fermi level. The optical reflectance spectra of Bi2OS2 and LaOBiS2 showed optical band gaps of ca. 1.0 eV, which were close to the computationally calculated direct band gaps of ca. 0.8 eV. Our results show that Bi2OS2 and LaOBiS2 are semiconductors containing direct band gaps of 0.8 1.0 eV, and they are suggested to be candidates for optoelectronic materials in the near infrared region without highly toxic elements.", "author_names": [ "Akira Miura", "Yoshikazu Mizuguchi", "Takahiro Takei", "Nobuhiro Kumada", "Eisuke Magome", "Chikako Moriyoshi", "Yoshihiro Kuroiwa", "Kiyoharu Tadanaga" ], "corpus_id": 124401262, "doc_id": "124401262", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Structures and Optical Properties of Bi2OS2 and LaOBiS2", "venue": "", "year": 2015 }, { "abstract": "The electron and phonon transport properties of layered bismuth oxychalcogenides Bi2OX2 (X S, Se) are studied by combining density functional theory calculation with the Boltzmann transport theory. It is found that Bi2OS2 and Bi2OSe2 are semiconductors with direct bandgaps of 0.86 eV and 0.63 eV, respectively. A large Seebeck coefficient is found in both p and n doped Bi2OX2 (X S, Se) at 300 K together with their low phonon thermal conductivity (kph) Through a detailed analysis of the phonon dispersion relation, relaxation time, and joint density of states, we find that the low frequency modes contribute dominantly to kph than the high frequency modes. Owing to the high Seebeck coefficient and the low kph, the largest figure of merit (ZT) value can reach 0.5 for the Bi2OX2. The results are useful for further tuning the thermoelectric properties of Bi2OX2 (X S, Se)", "author_names": [ "Hongyue Song", "Xu-Jin Ge", "Jing-Tao Lu" ], "corpus_id": 230637316, "doc_id": "230637316", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "First principles study on the electron and phonon transport properties of layered Bi2OX2 (X S, Se)", "venue": "", "year": 2020 }, { "abstract": "We have explored the optoelectronic structure and related thermoelectric properties of Bi2OX2 (X S, Se, Te) using density functional theory and spin orbit coupling (SOC) We report herein calculations of the bandgap of these bismuth sulfides/oxysulfides to participate in the recent debate regarding such values. The generalized gradient approximation calculations corrected using the SOC scheme estimated bandgaps of 0.950 eV, 0.635 eV, and 0.441 eV for Bi2OS2, Bi2OSe2, and Bi2OTe2, respectively, in close agreement with experimental results and showing better accuracy compared with available theoretical calculations. This bandgap range shows the potential use of Bi2OX2 for solar cell applications. Hence, we derived their optical and thermoelectric properties. Similarly to one of the parent materials, Bi2S3, a semiconductor with special photovoltaic and thermoelectric properties, the present derivatives Bi2OX2 show promising characteristics for exploration in the near future for use in solar cells and thermoelectric devices.", "author_names": [ "Sikander Azam", "Saleem Ayaz Khan", "Souraya Goumri-Said" ], "corpus_id": 103184759, "doc_id": "103184759", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Optoelectronic and Thermoelectric Properties of Bi2OX2 (X S, Se, Te) for Solar Cells and Thermoelectric Devices", "venue": "Journal of Electronic Materials", "year": 2018 } ]
Gd2CoMnO6
[ { "abstract": "The double perovskite gadolinium cobalt manganate (Gd2CoMnO6) ceramic material was prepared via mixed oxide route. The preliminary X ray structural study reveals that the material was found in monoclinic structure. We have found the small voids with almost uniform distribution of grains from the microstructural analysis. Analysis of the dielectric and electrical data, collected in a wide range of frequency range (1 kHz 1 MHz) and temperature (25 500 degC) has provided many interesting results. We have discussed frequency dependence dielectric parameter by Maxwell Wagner model. We found that the room temperature dielectric constant at 1 kHz frequency is 300 and tangent loss is nearly equal to 2. A dielectric anomaly (ferroelectric paraelectric phase transition) was found in the temperature dependence of dielectric study. The study of diffuse phase transition exhibits the existence of relaxation process in the compound. In the Nyquist plots, both grain and grain boundary effects are observed which is characterized by (RQC) and (RQC)(RC) circuits. As the resistance decreases with increase of temperature, the material shows the semiconductor behavior. The existence of non Debye type of relaxation mechanism in the material is confirmed by the depression angle. The frequency dependence of electric conductivity has been studied using the Jonscher's power law, in which the frequency exponent n 1) signifies the translational motion with involvement of an intuitive hopping of charge carriers. The leakage current and conduction mechanism follow the space charge limited conduction phenomenon. The low leakage current density may be suitable for high temperature applications.", "author_names": [ "Rutuparna Das", "Ram Naresh Prasad Choudhary" ], "corpus_id": 219985574, "doc_id": "219985574", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Synthesis and characterization of rare earth ion based double perovskite: Gd2CoMnO6", "venue": "Journal of Materials Science: Materials in Electronics", "year": 2020 }, { "abstract": "Abstract Structural, magnetization, phonon behavior, and dielectric response of nano crystalline Gd2CoMnO6 have been presented in this paper. The study shows that the material crystallizes in P21/n phase group of monoclinic crystal structure. XPS measurement shows Co2+ and Mn4+ oxidation states are present in the sample. Magnetization study reveals that sample undergoes a ferromagnetic ordering of Co2+ and Mn4+ magnetic ions around T c 132 K. Raman study shows the presence of spin phonon coupling in Gd2CoMnO6. Dielectric study reveals that the sample shows large dielectric constant and strong dispersion in mid frequency range. The dielectric loss shows there are two relaxation processes present in the material with different relaxation time and which are driven by thermally activated relaxation mechanics. Further, the Nyquist plot and AC conductivity study shows that this sample is non Debye's in nature.", "author_names": [ "Ilyas Noor Bhatti", "Imtiaz Noor Bhatti", "Rabindra Nath Mahato", "M A H Ahsan" ], "corpus_id": 224980986, "doc_id": "224980986", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Structure, magnetism and dielectric study of nano crystalline Gd2CoMnO6", "venue": "", "year": 2020 }, { "abstract": "Abstract Gd2CoMnO6 and Y2CoMnO6 double perovskite ceramics were obtained from the polymeric precursors method and investigated by X ray diffraction, X ray photoelectron spectroscopy (XPS) scanning electron microscopy (SEM) Raman and Fourier Transform Infrared (FTIR) spectroscopies. Our results show that these samples present similar structural and vibrational characteristics that are fully compatible with a monoclinic structure belonging to the P21/n space group, with ordered Co2+ and Mn4+ cations. Infrared reflectivity spectroscopy was employed to investigate the polar phonon features and to determine the intrinsic dielectric response of the materials. In particular, the extrapolated dielectric constants at the lower frequency infrared limit showed to be independent on the particle size, and were determined as e intr 17.8 and 16.0, for Gd2CoMnO6 and Y2CoMnO6, respectively. Otherwise, it is shown that for smaller RE radius the FTIR bands become more evidenced, due to a higher octahedral rotation and lower Co O Mn angle into the distorted monoclinic structure.", "author_names": [ "R X Silva", "R M Almeida", "Roberto Luiz Moreira", "Roberto M Paniago", "Marcos Vinicius dos Santos Rezende", "C W A Paschoal" ], "corpus_id": 139173764, "doc_id": "139173764", "n_citations": 9, "n_key_citations": 0, "score": 1, "title": "Vibrational properties and infrared dielectric features of Gd2CoMnO6 and Y2CoMnO6 double perovskites", "venue": "Ceramics International", "year": 2019 }, { "abstract": "Abstract 3d based double perovskite (DP) oxides having great research interest due to their physical properties with some great technological application. Magnetodielectric, magnetocaloric effect, ferroelectric, exotic magnetic phases etc are some properties that double perovskite materials shows, thus received attention of researchers. Magnetic refrigeration is the great cooling technology based on magnetocaloric effect due to high energy efficiency and environmental friendly. Recently, it is found that Gadolinium (Gd) have magnetic refrigerant properties because of large magnatochloric effects at room temperature. In this paper we present the double perovskite Gd2CoMnO6 nano crystalline which was prepared by sol gel method and its magnetic properties studied by vibrating sample magnetometer (VSM) There is a paramagnetic to ferromagnetic phase transition observed in the sample. We found that paramagnetic Curie Weiss temperature of Gd2CoMnO6 is around Tc 131.27 K. Further, temperature dependent inverse magnetic susceptibility (kh 1) shows deviation from curie Weiss behavior around TG 213 K which is depicts that Griffiths phase singularities is present in this material.", "author_names": [ "Ilyas Noor Bhatti", "Rabindra Nath Mahato", "Imtiaz Noor Bhattib", "M A H Ahsan" ], "corpus_id": 201327099, "doc_id": "201327099", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Synthesis and Magnetic Study of Nano Crystalline Gd2CoMnO6", "venue": "", "year": 2019 }, { "abstract": "Abstract Gd2CoMnO6 nanostructures (GCMO NSs) were synthesized through a simple combustion method at 800 degC calcination temperature in the presence of the different amino acids, including phenylalanine, beta alanine, leucine, valine and glycine, as combustion, gelling and stabilizing agents. In this work, metal nitrate salts were used as starting materials and the Gd:Co:Mn molar ratio was selected to be 2:1:1. The beta alanine was selected as the optimum amino acid. Effects of type of the amino acid and calcination temperature on the morphology and particle size of the products were investigated. X ray diffraction (XRD) Fourier transform infrared spectroscopy (FTIR) ultra violet diffuse reflectance spectroscopy (UV DRS) scanning electron microscopy (SEM) transmission electron microscopy (TEM) energy dispersive X ray (EDX) and vibrating sample magnetometer (VSM) were used for characterization and investigation of the applications of GCMO NSs. VSM results showed an antiferromagnetic behavior for the GCMO NSs. Optical properties of the NSs were investigated and the optical band gap of them was found to be 3.28 eV. Also photocatalytic properties of the GCMO NSs for the degradation of methyl violet, erythrosine and eriochrome black T were investigated.", "author_names": [ "Reza Mohassel", "Azam Sobhani", "Mojgan Goudarzi", "Masoud Salavati-Niasari" ], "corpus_id": 139537590, "doc_id": "139537590", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Amino acid modified combustion synthesis, characterization and investigation of magnetic, optical and photocatalytic properties of Gd2CoMnO6 nanostructures", "venue": "", "year": 2018 }, { "abstract": "GCMO NSs were synthesized by the reaction of metal nitrate salts in the presence of stabilizing agent and PG, by a Pechini method. Citric acid, maleic acid, succinic acid and 1,3,5 benzenetricarboxylic acid were used as stabilizing agents. The structure, morphology, optical, magnetic and photocatalytic properties of the GCMO NSs were investigated using various characterization techniques. Effects of type of stabilizing agent, the molar ratio of stabilizing agent:PG and also calcination temperature on particle size and morphology of the products were investigated. Also the influence of kind of pollutant on photocatalytic behavior of GCMO NSs was evaluated.", "author_names": [ "Reza Mohassel", "Azam Sobhani", "Masoud Salavati-Niasari", "Mojgan Goudarzi" ], "corpus_id": 49477933, "doc_id": "49477933", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Pechini synthesis and characteristics of Gd2CoMnO6 nanostructures and its structural, optical and photocatalytic properties.", "venue": "Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy", "year": 2018 }, { "abstract": "The phenomenon of magnetocaloric effect occurring around the ordering temperatures for Gd2 xSrxCoMnO6 (x 0 and 0.5) has been investigated in order to disclose the effects of Sr substitution on the individual collinear Gd spin order. It is shown that 25% Sr substitution of Gd ions significantly suppresses the independent spin order, leading to enhancement of ferromagnetism. As a result, magnetic entropy change DSM) increases from +0.9 J kg 1 K 1 to +3.7 J kg 1 K 1 at Curie temperature for a change in magnetic field (DH) 6.9 T. On the other hand, the DSM changes sign at Neel temperature due to the effect of Sr substitution. We have also observed noticeably large DSM +25.84 J kg 1 K 1) and +21.01 J kg 1 K 1) for DH 6.9 T at 4f 4f negative coupling temperature (T 10 K) of x 0 and x 0.5 samples, respectively.The phenomenon of magnetocaloric effect occurring around the ordering temperatures for Gd2 xSrxCoMnO6 (x 0 and 0.5) has been investigated in order to disclose the effects of Sr substitution on the individual collinear Gd spin order. It is shown that 25% Sr substitution of Gd ions significantly suppresses the independent spin order, leading to enhancement of ferromagnetism. As a result, magnetic entropy change DSM) increases from +0.9 J kg 1 K 1 to +3.7 J kg 1 K 1 at Curie temperature for a change in magnetic field (DH) 6.9 T. On the other hand, the DSM changes sign at Neel temperature due to the effect of Sr substitution. We have also observed noticeably large DSM +25.84 J kg 1 K 1) and +21.01 J kg 1 K 1) for DH 6.9 T at 4f 4f negative coupling temperature (T 10 K) of x 0 and x 0.5 samples, respectively.", "author_names": [ "R C Sahoo", "S Das", "Tapan Kumar Nath" ], "corpus_id": 125764431, "doc_id": "125764431", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Role of Gd spin ordering on magnetocaloric effect and ferromagnetism in Sr substituted Gd2CoMnO6 double perovskite", "venue": "", "year": 2018 }, { "abstract": "The magnetocaloric effect (MCE) is described by the change in temperature of a material by magnetic field variation and is a crucial subject in magnetism; it is motivated by the desire to enhance energy efficient magnetic refrigeration for clean technology. Despite the recent discovery of the giant cryogenic MCE in double perovskites, the role of magnetic anisotropy has not yet been clearly discussed, because of the averaging effect of polycrystalline samples. Here, we investigated the anisotropic MCE in the single crystal double perovskite Gd2CoMnO6. In addition to the ferromagnetic order of the Co2+ and Mn4+ moments, the large Gd3+ moments align below TGd 21 K, exhibiting an isotropic nature. Because of the intricate temperature development of magnetically hysteretic behaviour and metamagnetism, the change in magnetic entropy along the c axis appears to be relatively small. On the contrary, the smaller but almost reversible magnetization perpendicular to the c axis leads to a large MCE with a maximum entropy change of 25.4 J/kg*K. The anisotropic MCE generates a giant rotational MCE, estimated as 16.6 J/kg*K. Our results demonstrate the importance of magnetic anisotropy for understanding the MCE and reveal essential clues for exploring suitable magnetic refrigerant compounds aiming at magnetic functional applications.", "author_names": [ "Jae Young Moon", "M K Kim", "Y J Choi", "Nara Lee" ], "corpus_id": 205629687, "doc_id": "205629687", "n_citations": 36, "n_key_citations": 0, "score": 0, "title": "Giant Anisotropic Magnetocaloric Effect in Double perovskite Gd2CoMnO6 Single Crystals", "venue": "Scientific Reports", "year": 2017 }, { "abstract": "Abstract Double perovskite R 2 CoMnO 6 systems, with magnetically active rare earth (R) elements, have attracted much attention because of their interesting field sensitive magnetic phenomena and remarkable physical properties. The perovskite compound Gd 2 CoMnO 6 exhibits a field induced metamagnetic phase transition from ferrimagnetic to long range ferromagnetic (FM) ordering below a critical temperature of T C ~112 K. It also shows polarization of the Co/Mn magnetic sublattice to the Gd moments resulting in antiferromagnetic (AFM) like behaviour at T N ~47 K. Further, the large change in magnetization at low temperatures of T 3+ excitations. A sharp peak at T C in AC susceptibility measurements reveals that susceptibility is the sum of the true critical maximum and Hopkinson peak contributions. Below T N ~47 K, the 4 f 3 d negative exchange interaction is responsible for the observed antiferromagnetic spin polarizations; consequently the exchange bias (EB) effect originates from the unidirectional anisotropy induced at the antiferromagnetic/ferromagnetic interface.", "author_names": [ "J Krishna Murthy", "Adyam Venimadhav" ], "corpus_id": 136076399, "doc_id": "136076399", "n_citations": 23, "n_key_citations": 0, "score": 0, "title": "4f 3d exchange coupling induced exchange bias and field induced Hopkinson peak effects in Gd2CoMnO6", "venue": "", "year": 2017 }, { "abstract": "We have investigated magnetocaloric effect in double perovskite Gd2NiMnO6 (GNMO) and Gd2CoMnO6 (GCMO) samples by magnetic and heat capacity measurements. Ferromagnetic ordering is observed at ~130 K ~112 K) in GNMO (GCMO) while the Gd exchange interactions seem to dominate for T 20 K. In GCMO, below 50 K, an antiferromagnetic behaviour due to 3d 4f exchnage interaction is observed. A maximum entropy \\Delta}SM) and adiabatic temperature change of ~35.5 J Kg 1 K 1 ~24 J Kg 1 K 1) and 10.5 K (6.5 K) is observed in GNMO (GCMO) for a magnetic field change of 7 T at low temperatures. Absence of magnetic and thermal hysteresis and their insulating nature make them promising for low temperature magnetic refrigeration.", "author_names": [ "J Krishna Murthy", "K Devi Chandrasekhar", "Sudipta Mahana", "Dinesh Topwal", "Adyam Venimadhav" ], "corpus_id": 119256318, "doc_id": "119256318", "n_citations": 45, "n_key_citations": 0, "score": 0, "title": "Giant magnetocaloric effect in Gd2NiMnO6 and Gd2CoMnO6 ferromagnetic insulators", "venue": "", "year": 2015 } ]
organic semiconductor environment
[ { "abstract": "Development of carbon neutral and sustainable energy sources should be considered as a top priority solution for the growing worldwide energy demand. Photovoltaics are a strong candidate, more specifically, organic photovoltaics (OPV) enabling the design of flexible, lightweight, semitransparent, and low cost solar cells. However, the active layer of OPV is, for now, mainly deposited from chlorinated solvents, harmful for the environment and for human health. Active layers processed from health and environmentally friendly solvents have over recent years formed a key focus topic of research, with the creation of aqueous dispersions of conjugated polymer nanoparticles arising. These nanoparticles are formed from organic semiconductors (molecules and macromolecules) initially designed for organic solvents. The topic of nanoparticle OPV has gradually garnered more attention, up to a point where in 2018 it was identified as a \"trendsetting strategy\" by leaders in the international OPV research community. Hence, this review has been prepared to provide a timely roadmap of the formation and application of aqueous nanoparticle dispersions of active layer components for OPV. We provide a thorough synopsis of recent developments in both nanoprecipitation and miniemulsion for preparing photovoltaic inks, facilitating readers in acquiring a deep understanding of the crucial synthesis parameters affecting particle size, colloidal concentration, ink stability, and more. This review also showcases the experimental levers for identifying and optimizing the internal donor acceptor morphology of the nanoparticles, featuring cutting edge X ray spectromicroscopy measurements reported over the past decade. The different strategies to improve the incorporation of these inks into OPV devices and to increase their efficiency (to the current record of 7.5% are reported, in addition to critical design choices of surfactant type and the advantages of single component vs binary nanoparticle populations. The review naturally culminates by presenting the upscaling strategies in practice for this environmentally friendly and safer production of solar cells.", "author_names": [ "Alexandre Holmes", "Elise Deniau", "Christine Lartigau-Dagron", "Antoine Bousquet", "Sylvain Chambon", "Natalie P Holmes" ], "corpus_id": 232017608, "doc_id": "232017608", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Review of Waterborne Organic Semiconductor Colloids for Photovoltaics.", "venue": "ACS nano", "year": 2021 }, { "abstract": "Photocatalytic applications of halide perovskites have attracted increasing attention. However, lack of stability and lead toxicity of lead halide perovskites have hindered their applications. Metal halide double perovskite (DP) Cs2AgInCl6 is a stable, environment friendly semiconductor with direct band gap, and then the best promising alternative to lead halide perovskites. Here, the applications of Cs2AgInCl6 DP to photocatalytic degradation of organic pollutants have been developed, in which the octahedral Cs2AgInCl6 DP particles ~3.33 eV) were prepared by precipitation from acid solutions. The as prepared samples exhibit high photocatalytic activity, which can degrade about 98.5% of water insoluble carcinogen Sudan Red III in only 16 min, and have a good stability for 5 cycle operations. Furthermore, the Cs2AgInCl6 DP also can degrade Rhodamine B, Methyl orange and Methyl red efficiently, demonstrating a highly efficient and stable ethanol solvent based photocatalytic system for organic pollutants degradation. The high photocatalytic activity could be attributed to direct band gap and long carrier lifetime of Cs2AgInCl6 DP. These unique features of Cs2AgInCl6 DP indicate that it could have a good application prospect for photocatalytic degradation of organic pollutants.", "author_names": [ "Sen Li", "Wule Zhang", "Zhifeng Shi", "Di Wu", "Xu Chen", "Pei Lin", "Yongtao Tian", "Xinjian Li" ], "corpus_id": 233234266, "doc_id": "233234266", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Highly efficient and stable photocatalytic activity of lead free Cs2AgInCl6 double perovskite for organic pollutant degradation.", "venue": "Journal of colloid and interface science", "year": 2021 }, { "abstract": "Heavy metal pollution in the environment poses a serious threat to the ecosystem and human health, which has attracted widespread attention. In this study, an octahedral structure composite composed of UiO 66 NH2 MOFs and semiconductor GaOOH materials has been prepared and used as electrode materials successfully. These composites can be used for the real time and online determination of Cd2+ Cu2+ Hg2+ and Pb2+ in real water samples simultaneously or alone via an electrochemical method. Zr MOF has a large and unique surface area that is beneficial to the adsorption and preconcentration of heavy metal ions. The experiment parameters such as pH, deposition potential, and deposition time were optimized. Under the optimized conditions, the electrochemical performances and practical applications of Zr MOF composites modified electrode have been investigated, which shows excellent wider linear range and lower detection limit (LOD) The results demonstrated excellent selectivity, reproducibility, stability and applicability for the detection of four metal ions. These superior features stem from the synergistic reaction mechanism of UiO 66 NH2 and GaOOH. In addition, it has been established a new detection strategy for heavy metal ions through the form of metal organic framework (MOF) composite in this work. It may provide a novel platform for the quantitative determination of heavy metal ions in various environmental samples.", "author_names": [ "Jing Ru", "Xuemei Wang" ], "corpus_id": 236959698, "doc_id": "236959698", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "GaOOH modified metal organic frameworks UiO 66 NH2: Selective and sensitive sensing four heavy metal ions in real wastewater by electrochemical method.", "venue": "Talanta", "year": 2021 }, { "abstract": "Technologies for wastewater remediation have been growing ever since the environmental and health concern is realised. Development of nanomaterials has enabled mankind to have different methods to treat the various kind of inorganic and organic pollutants present in wastewater from many resources. Among the many materials, semiconductor materials have found many environmental applications due to their outstanding photocatalytic activities. TiO2 and ZnO are more effectively used as photocatalyst or adsorbents in the withdrawal of inorganic as well as organic wastes from the wastewater. On the other hand, graphene is tremendously being investigated for applications in environmental remediation in view of the superior physical, optical, thermal and electronic properties of graphene nanocomposites. In this work, graphene TiO2 and graphene ZnO nanocomposites have been reviewed for photocatalytic wastewater treatment. The various preparation techniques of these nanocomposites have been discussed. Also, different design strategies for graphene based photocatalyst have been revealed. These nanocomposites exhibit promising applications in most of the water purification processes which are reviewed in this work. Along with this, the development of these nanocomposites using biomass derived graphene has also been introduced.", "author_names": [ "Kunal G Thakre", "Divya P Barai", "Bharat Apparao Bhanvase" ], "corpus_id": 236978129, "doc_id": "236978129", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A review of graphene TiO2 and graphene ZnO nanocomposite photocatalysts for wastewater treatment.", "venue": "Water environment research a research publication of the Water Environment Federation", "year": 2021 }, { "abstract": "The recent and vigorous developments in semiconductor technology strictly request better quality and large quantity of ultrapure water (UPW) for their production. It is crucial to secure a large amount of raw water for the future development of UPW production. Using reclaimed water as alternative raw water source to produce UPW is therefore considered the feasible trend and solution for sustainable use of water resources towards a common future practice in UPW production. The challenge of using reclaimed water is due to its higher content of organic pollutants, especially small molecule organic pollutants such as urea, which are difficult to remove through traditional UPW production process. Consequently, improving the existing UPW production process to meet the water standard desired in the semiconductor industry is essential. This paper reviewed the current traditional processes for removing organic matters in UPW production, including ion exchange (IX) adsorption, granular activated carbon (GAC) adsorption, reverse osmosis (RO) and ultraviolet (UV) irradiation. The potential problems in the actual UPW production process were identified when using reclaimed water as raw water source. A new strategy of applying the advanced oxidation process (AOPs) to UPW production as a supplementary unit to guarantee UPW quality was proposed. Its feasibility and research focus were then analyzed and discussed in obtaining a new solution for a future development of the UPW production process.", "author_names": [ "Xinbo Zhang", "Yuanying Yang", "Huu Hao Ngo", "Wenshan Guo", "Haitao Wen", "Xiao Wang", "Jian-qing Zhang", "Tianwei Long" ], "corpus_id": 233484326, "doc_id": "233484326", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A critical review on challenges and trend of ultrapure water production process.", "venue": "The Science of the total environment", "year": 2021 }, { "abstract": "The use of the anammox process for nitrogen removal has gained popularity across the world due to its low energy consumption and waste generation. Anammox reactors have been used to treat ammonium rich effluents such as chemical, pharmaceutical, semiconductor, livestock, and coke oven wastewater. Recently, full scale installations have been implemented for municipal wastewater treatment. The efficiency of biological processes is susceptible to inhibitory effects of pollutants present in wastewater. Considering the increasing number of emerging contaminants detected in wastewater, the impacts of the different types of pollutants on anammox bacteria must be understood. This review presents a compilation of the studies assessing the inhibitory effects of different wastewater pollutants towards anammox activity. The pollutants were classified as antibiotics, aromatics, azoles, surfactants, microplastics, organic solvents, humic substances, biodegradable organic matter, or metals and metallic nanoparticles. The interactions between the pollutants and anammox bacteria have been described, as well as the interactions between different pollutants leading to synergistic effects. We also reviewed the effects of pollutants on distinct species of anammox bacteria, and the main toxicity mechanisms leading to irreversible loss of anammox activity have been identified. Finally, we provided an analysis of strategies to overcome the inhibitory effects of wastewater pollutants on the nitrogen removal performance. We believe this review will contribute with essential information to assist the operation and design of anammox reactors treating different types of wastewaters.", "author_names": [ "Camila L Madeira", "Juliana Calabria de Araujo" ], "corpus_id": 236968080, "doc_id": "236968080", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Inhibition of anammox activity by municipal and industrial wastewater pollutants: A review.", "venue": "The Science of the total environment", "year": 2021 }, { "abstract": "A recent research emphasis has been placed on the development of highly crystallized nanostructures as a useful technology for many photocatalytic applications. With the unique construction of semiconductor transition metal oxide nanostructures in the form of nanopillars artificially designed pillar shaped structures grouped together in lattice type arrays the surface area for photocatalytic potential is increased and further enhanced through the introduction of dopants. This short review summarizes the work on improving the efficiency of photocatalyst nanopillars through increased surface area and doping within the applications of water splitting, removal of organic pollutants from the environment, photoswitching, soot oxidation, and photothermalization.", "author_names": [ "Jessica L Waite", "Julianna Hunt", "Haifeng Ji" ], "corpus_id": 231584879, "doc_id": "231584879", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Improving Photocatalytic Performance Using Nanopillars and Micropillars", "venue": "Materials", "year": 2021 }, { "abstract": "Contact electrification activated triboelectric potential offers an efficient route to tuning the transport properties in semiconductor devices through electrolyte dielectrics, i.e. triboiontronics. Organic electrochemical transistors (OECTs) make more effective use of ion injection in the electrolyte dielectrics by changing the doping state of the semiconductor channel. However, the mainstream flexible/wearable electronics and OECT based devices are usually modulated by electrical signals and constructed in conventional geometry, which lack direct and efficient interaction between the external environment and functional electronic devices. Here, we demonstrate a fiber shaped triboiontronic electrochemical transistor with good electrical performances, including a current on/off ratio as high as 1286 with off current at ~nA level, the average threshold displacements (Dth) of 0.3 mm, the subthreshold swing corresponding to displacement (SSD) at 1.6 mm/dec, and excellent flexibility and durability. The proposed triboiontronic electrochemical transistor has great potential to be used in flexible, functional, and smart self powered electronic textile.", "author_names": [ "Shanshan Qin", "Huai Zhang", "Yichen Wei", "Xiaoxiao Zhu", "Ya Yang", "Qijun Sun" ], "corpus_id": 233218283, "doc_id": "233218283", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Fiber Shaped Triboiontronic Electrochemical Transistor", "venue": "Research", "year": 2021 }, { "abstract": "With the rapid development of society, the burden of energy and the environment is becoming more and more serious. Photocatalytic hydrogen production, the photosynthesis of organic fuel, and the photodegradation of pollutants are three effective ways to reduce these burdens using semiconductor photocatalysts. To improve the reaction efficiency of photocatalysts, a small amount of cocatalyst is often added when photocatalysts participate in the synthesis or decomposition reaction. The addition of this small amount of cocatalyst is like a finishing touch, significantly increasing the activity of the photocatalysts. However, in our common study of photocatalysis, we often pay attention to the study of photocatalysts but ignore the study of cocatalysts. Herein, we summarize the recent application research on cocatalysts in the field of photocatalysis, starting from the types, preparation methods, and reaction mechanisms among others, to remind researchers of the matters needing attention when using cocatalysts.", "author_names": [ "Gang Zhao", "Xijin Xu" ], "corpus_id": 235379517, "doc_id": "235379517", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Cocatalysts from types, preparation to applications in the field of photocatalysis.", "venue": "Nanoscale", "year": 2021 }, { "abstract": "Over the past several decades, organic conjugated materials as semiconductors in organic field effect transistors (OFETs) have attracted more and more attention from the scientific community due to their intriguing properties of mechanical flexibility and solution processability. However, the device fabrication technique, design, and synthesis of novel organic semiconductor materials with high charge carrier mobility is crucial for the development of high performance OFETs. In the past few years, more and more novel materials were designed and tested in the OFETs. Among which, diketopyrrolopyrrole (DPP) and its derivatives, as the electron acceptors to build donor acceptor (D A) typed materials, are the perspective. In this article, recently reported molecules regarding the DPP and its derivatives for OFETs application are reviewed. In addition, the relationship between the chemical structures and the performance of the device are discussed. Furthermore, an outlook of DPP based materials in OFETs with a future design concept and the development trend are provided.", "author_names": [ "Xiangyu Zou", "Shuaiwei Cui", "Junqiang Li", "Xueling Wei", "Meng Zheng" ], "corpus_id": 233228722, "doc_id": "233228722", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Diketopyrrolopyrrole Based Organic Semiconductor Materials for Field Effect Transistors", "venue": "Frontiers in Chemistry", "year": 2021 } ]
4H-SiC
[ { "abstract": "This paper gives an overview on some state of the art characterization methods of SiO2/4H SiC interfaces in metal oxide semiconductor field effect transistors (MOSFETs) In particular, the work compares the benefits and drawbacks of different techniques to assess the physical parameters describing the electronic properties and the current transport at the SiO2/SiC interfaces (interface states, channel mobility, trapping phenomena, etc. First, the most common electrical characterization techniques of SiO2/SiC interfaces are presented (e.g. capacitance and current voltage techniques, transient capacitance, and current measurements) Then, examples of electrical characterizations at the nanoscale (by scanning probe microscopy techniques) are given, to get insights on the homogeneity of the SiO2/SiC interface and the local interfacial doping effects occurring upon annealing. The trapping effects occurring in SiO2/4H SiC MOS systems are elucidated using advanced capacitance and current measurements as a function of time. In particular, these measurements give information on the density ~1011 cm 2) of near interface oxide traps (NIOTs) present inside the SiO2 layer and their position with respect to the interface with SiC (at about 1 2 nm) Finally, it will be shown that a comparison of the electrical data with advanced structural and chemical characterization methods makes it possible to ascribe the NIOTs to the presence of a sub stoichiometric SiOx layer at the interface.", "author_names": [ "Patrick Fiorenza", "Filippo Giannazzo", "Fabrizio Roccaforte" ], "corpus_id": 197453161, "doc_id": "197453161", "n_citations": 36, "n_key_citations": 0, "score": 1, "title": "Characterization of SiO2/4H SiC Interfaces in 4H SiC MOSFETs: A Review", "venue": "Energies", "year": 2019 }, { "abstract": "Abstract In this manuscript, an ultralow dark current solar blind photodetector based on b Ga2O3/4H SiC heterojunction is generated by depositing b Ga2O3 thin film on n type 4H SiC substrates using Pulse Laser Deposition method. It is found that the excellent performances of our device with ultralow dark current (0.167 nA) as well as high Iphoto/Idark ration (384.3) are obtained with thermal annealing at optimized temperature, which is due to the improvement of interface defects in the b Ga2O3/4H SiC heterojunction through high temperature annealing. Moreover, the detectivity and linear dynamic range of the device are high as 8.23 x 1011 Jones and 51.70 dB, respectively, along with faster response speed (a rise time of 0.18 s and a decay time of 0.31s) which are attributed to the co effect of reducing in defects at the interface of heterojunction and the existence of appropriate amount of mixed crystal orientation in b Ga2O3 films with the optimizing the annealing temperature. The electronic transport mechanism in the b Ga2O3/4H SiC heterojunction photodetector is proposed in details with the energy band diagram.", "author_names": [ "Jiangang Yu", "Zizhuo Nie", "Linpeng Dong", "Lei Yuan", "Dejun Li", "Yu Huang", "Lichun Zhang", "Yuming Zhang", "Renxu Jia" ], "corpus_id": 181339113, "doc_id": "181339113", "n_citations": 24, "n_key_citations": 0, "score": 1, "title": "Influence of annealing temperature on structure and photoelectrical performance of b Ga2O3/4H SiC heterojunction photodetectors", "venue": "Journal of Alloys and Compounds", "year": 2019 }, { "abstract": "Abstract In this study, the structural stability and electronic properties of Al(111)/4H SiC(0001) interface, as well as the effects of Ti, Si, Mg and Cu additions on the interfacial adhesive strength are investigated via the first principles method. Surface energy calculations show that 4H SiC(0001) with C termination is more active than Si termination. Moreover, polar covalent bonds are formed across Al/4H SiC interface. The results of separation energies suggest that the introduction of Ti and Si can improve the adhesive strength of C terminated Al(111)/4H SiC(0001) interface, whereas Mg and Cu have the opposite effect. According to the analysis of interfacial electronic structure, the covalent bonds across Al/4H SiC interface are further enhanced with the addition of Ti and Si atoms, contributing to the improved adhesive strength in this case. However, the interactions between interfacial atoms are weakened with Mg and Cu doped in C terminated interface, which results in the decrease of interfacial adhesion strength. Our calculations provide a guide to experiments on the design of 4H SiC reinforced Al matrix composites with tailored properties.", "author_names": [ "Xin-yu Xu", "Huiyuan Wang", "Mingzheng Zha", "Cheng Yang Wang", "Zhizheng Yang", "Qi-chuan Jiang" ], "corpus_id": 103530401, "doc_id": "103530401", "n_citations": 34, "n_key_citations": 0, "score": 0, "title": "Effects of Ti, Si, Mg and Cu additions on interfacial properties and electronic structure of Al(111)/4H SiC(0001) interface: A first principles study", "venue": "", "year": 2018 }, { "abstract": "The slow etching rate of conventional micro machining processes is hindering the use of bulk silicon carbide materials in pressure sensing. This paper presents a 4H SiC piezoresistive pressure sensor utilising a laser scribing approach for fast prototyping a bulk SiC pressure sensor. The sensor is able to operate at a temperature range from cryogenic to elevated temperatures with an excellent linearity and repeatability with a pressure of up to 270 kPa. The good optical transparency of SiC material allows the direct alignment between the pre fabricated piezoresistors and the scribing process to form a diaphragm from the back side. The sensitivities of the sensor were obtained as 10.83 mV/V/bar at 198 K and 6.72 mV/V/bar at 473 K, which are at least a two fold increment in comparison with other SiC pressure sensors. The high sensitivity and good reliability at either cryogenic and elevated temperatures are attributed to the profound piezoresistive effect in p type 4H SiC and the robust p n junction which prevents the current from leaking to the substrate. This indicates the potential of utilising the laser scribing approach to fabricate highly sensitive bulk SiC pressure sensors for harsh environment applications.", "author_names": [ "Tuan-Khoa Nguyen", "Hoang-Phuong Phan", "Toan Dinh", "Karen M Dowling", "Abu Riduan Md Foisal", "Debbie G Senesky", "Nam-Trung Nguyen", "Dzung Viet Dao" ], "corpus_id": 139430641, "doc_id": "139430641", "n_citations": 31, "n_key_citations": 1, "score": 0, "title": "Highly sensitive 4H SiC pressure sensor at cryogenic and elevated temperatures", "venue": "", "year": 2018 }, { "abstract": "We study an electron spin resonance (ESR) signal of carbon dangling bond defects at 4H SiC(0001)/SiO2 interfaces, which we call an \"interface carbon defect.\" The ESR signal is close to a c axial type of the PbC centers (interfacial carbon dangling bonds) that have originally been found in porous SiC/SiO2 interfaces. The interface carbon defects were always formed with an areal density of 3 4 x 1012 cm 2 after the standard dry oxidation of 4H SiC(0001) surfaces. They act as electron traps and decrease the amount of free electrons in the channel region, consequently reducing the field effect mobility of Si face 4H SiC MOSFETs. They were eliminated by optimum post oxidation anneals (POAs) in either NO or POCl3 environment. Furthermore, POCl3 POAs at 1000 degC introduced a high density (1.7 x 1012 cm 2) of phosphorus donors into the channel region, increasing the free carrier density as compared with the case of NO POAs.", "author_names": [ "Takahide Umeda", "Geon Woo Kim", "Takafumi Okuda", "Mitsuru Sometani", "Tsunenobu Kimoto", "Shinsuke Harada" ], "corpus_id": 125377872, "doc_id": "125377872", "n_citations": 18, "n_key_citations": 0, "score": 1, "title": "Interface carbon defects at 4H SiC(0001)/SiO2 interfaces studied by electron spin resonance spectroscopy", "venue": "", "year": 2018 }, { "abstract": "In this work, the isotropic piezoresistance in the (0001) plane of p type 4H SiC was discovered by means of the hole energy shift calculation and the coordinate transformation. These results were also confirmed by the measurement of the piezoresistance using a bending beam method. The fundamental longitudinal and transverse piezoresistive coefficients p11 and p12 were found to be 6.43 x 10 11 Pa 1 and 5.12 x 10 11 Pa 1, respectively. The isotropy of the piezoresistance in the basal plane of p type 4H SiC is attributed to the isotropic hole energy shift under uniaxial strain. This interesting phenomenon in p type 4H SiC is promising for the design and fabrication of mechanical sensors and strain engineered electronics since high sensitivity and consistent performance can be achieved regardless of the crystallographic orientation.", "author_names": [ "Tuan-Khoa Nguyen", "Hoang-Phuong Phan", "Toan Dinh", "Toshiyuki Toriyama", "Koichi Shimizu Nakamura", "Abu Riduan Md Foisal", "Nam-Trung Nguyen", "Dzung Viet Dao" ], "corpus_id": 126068332, "doc_id": "126068332", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Isotropic piezoresistance of p type 4H SiC in (0001) plane", "venue": "", "year": 2018 }, { "abstract": "4H silicon carbide based sensors are promising candidates for replacing prevalent silicon based counterparts in harsh environments owing to their superior chemical inertness, high stability and reliability. However, the wafer cost and the difficulty in obtaining an ohmic contact in the metallization process hinders the use of this SiC polytype for practical sensing applications. This article presents the high temperature tolerance of a p type 4H SiC piezoresistor at elevated temperatures up to 600 degC. A good ohmic contact was formed by the metallisation process using titanium and aluminium annealed at 1000 degC. The leakage current at high temperatures was measured to be negligible thanks to a robust p n junction. Owing to the superior physical properties of the bulk 4H SiC material, a high gauge factor of 23 was obtained at 600 degC. The piezoresistive effect also exhibits good linearity and high stability at high temperatures. The results demonstrate the capability of p type 4H SiC for the development of highly sensitive sensors for hostile environments.", "author_names": [ "Tuan-Khoa Nguyen", "Hoang-Phuong Phan", "Toan Dinh", "Abu Riduan Md Foisal", "Nam-Trung Nguyen", "Dzung Viet Dao" ], "corpus_id": 139490694, "doc_id": "139490694", "n_citations": 19, "n_key_citations": 0, "score": 0, "title": "High temperature tolerance of the piezoresistive effect in p 4H SiC for harsh environment sensing", "venue": "", "year": 2018 }, { "abstract": "Short term demonstrations of packaged 4H SiC junction field effect transistor (JFET) logic integrated circuits (ICs) at temperatures exceeding 800 degC in air are reported, including a 26 transistor 11 stage ring oscillator that functioned at 961 degC ambient temperature believed unprecedented for electrical operation of a semiconductor IC. The expanded temperature range should assist temperature acceleration testing/qualification of such ICs intended for long term use in applications near 500 degC ambient, and perhaps spawn new applications. Ceramic package assembly leakage currents inhibited the determination of some intrinsic SiC device/circuit performance properties at these extreme temperatures, so it is conceivable that even higher operating temperatures might be obtained from SiC JFET ICs by employing packaging and circuit design intended/optimized for T <inline formula> <tex math notation=\"LaTeX\"\\ge800$ /tex math>/inline formula> degC.", "author_names": [ "Philip G Neudeck", "David J Spry", "Liangyu Chen", "Norman F Prokop", "Michael J Krasowski" ], "corpus_id": 22909700, "doc_id": "22909700", "n_citations": 53, "n_key_citations": 0, "score": 0, "title": "Demonstration of 4H SiC Digital Integrated Circuits Above 800 degC", "venue": "IEEE Electron Device Letters", "year": 2017 }, { "abstract": "Defects in silicon carbide (SiC) have emerged as a favorable platform for optically active spin based quantum technologies. Spin qubits exist in specific charge states of these defects, where the ability to control these states can provide enhanced spin dependent readout and long term charge stability. We investigate this charge state control for two major spin qubits in 4H SiC, the divacancy and silicon vacancy, obtaining bidirectional optical charge conversion between the bright and dark states of these defects. We measure increased photoluminescence from divacancy ensembles by up to three orders of magnitude using near ultraviolet excitation, depending on the substrate, and without degrading the electron spin coherence time. This charge conversion remains stable for hours at cryogenic temperatures, allowing spatial and persistent patterning of the charge state populations. We develop a comprehensive model of the defects and optical processes involved, offering a strong basis to improve material design and to develop quantum applications in SiC.Defects in silicon carbide represent a viable candidate for realization of spin qubits. Here, the authors show stable bidirectional charge state conversion for the silicon vacancy and divacancy, improving the photoluminescence intensity by up to three orders of magnitude with no effect on spin coherence.", "author_names": [ "Gary Wolfowicz", "Christopher P Anderson", "Andrew L Yeats", "Samuel J Whiteley", "Jens Niklas", "Oleg G Poluektov", "F Joseph Heremans", "David D Awschalom" ], "corpus_id": 1468241, "doc_id": "1468241", "n_citations": 56, "n_key_citations": 3, "score": 0, "title": "Optical charge state control of spin defects in 4H SiC", "venue": "Nature Communications", "year": 2017 }, { "abstract": "Abstract Based on density functional theory (DFT) first principles method, we have investigated the electronic structures and magnetic properties of (Ni,Al) co doped 4H SiC system. Various configurations of Ni sites have been considered to confirm the most stable geometric construction. Comparing with pure 4H SiC, the magnetic moment of Ni doped 4H SiC is increased, which is attributed to the hybridization of Ni:4s and C:2p orbitals. Moreover, we found that it is the 3d orbital of Ni that induces the spin polarized state in Ni doped 4H SiC. In addition, the origin of ferromagnetic coupling between Ni doped 4H SiC has been predicted to be the ferromagnetic orders activated by the Ni0:3d C:2p Ni2:3d coupling chains. For (Ni,Al) co doped system, we found that ferromagnetic stability is reduced significantly. For (2Ni, V Si co doped 4H SiC system, the antiferromagnetic state is more stable than ferromagnetic state with E FM of 97.2 meV, and the system changes from ferromagnetism to anti ferromagnetism. These results provide a new route for the potential applications of dilute magnetic semiconductors in spintronic devices by employing doped 4H SiC.", "author_names": [ "Long Lin", "Jingtao Huang", "Weiyang Yu", "Hualong Tao", "Linghao Zhu", "Pengtao Wang", "Zhanying Zhang", "Jisheng Zhang" ], "corpus_id": 139331461, "doc_id": "139331461", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Electronic structures and magnetic properties of (Ni,Al) co doped 4H SiC: A first principles study", "venue": "", "year": 2018 } ]
Major verilog
[ { "abstract": "In semiconductor industries, speed of operation and the size of the computational devices are playing a major role. Size of a single transistor may limit the scaling of semiconductor devices. In turn, an alternative technology is needed for faster computation and to reduce the size of computational devices. One such technology is Reversible Logic. Parity preserving is a property that is added to reversible gates with the help of which, presence of errors can be detected. In this Paper, Parity Preserving Reversible Floating point multiplier (RFPM) which uses IEEE 754 standard representation is proposed using P2RG and Fredkin Reversible gates. This RFPM uses Carry select adder for Exponent addition and Carry save Multiplier for Mantissa multiplication. The architecture also includes a multiplexer, Bit slicer, rounding and normalization register. This Pipelined RFPM architecture is coded using Verilog and the same has been simulated using Modelsim 10.7c. Parameters such as Area, Power, Cell Utilization and Maximum operating frequency have been analyzed using Cadence Genus Synthesis 14.25. On Comparison of Pipelined RFPM with Non Pipelined RFPM between 180nm and 90nm technology, the results show that Pipelined RFPM using 90nm technology, occupies lesser Area and uses lesser number of cells by 67.17% and 4.42% respectively whereas, the Maximum operating frequency has increased by a factor of 2.73.", "author_names": [ "F Mhaboobkhan", "Karuppannan Kokila", "R Jothikha", "K Lakshmi Preethikha" ], "corpus_id": 216104933, "doc_id": "216104933", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Design of Pipelined Parity Preserving Double Precision Reversible Floating Point Multiplier Using 90 nm Technology", "venue": "2020 6th International Conference on Advanced Computing and Communication Systems (ICACCS)", "year": 2020 }, { "abstract": "Image enhancement plays an important role in all fields of applications, like biomedical, satellite images, graphical applications and many others. In today's world everything needs to work in real time, hence this study talks about the implementation of image enhancement technique. This technique uses hardware approach for analysing the quality of an image which gives less time and can be worked for parallel processing applications. As histogram of an image contains details such as pixel intensity, distribution of grey levels helps to understand and analyse the quality of an image. Here, we have proposed an efficient architecture for image enhancement technique and was simulated using Verilog HDL. This study outlines brightness enhancement and contrast stretching method which permits better visual appearance of an image. Also here we have proposed design for finding region of interest in an image by developing eight different grey levels which can be used in detecting object in an image as it is one of the major areas of research in biometric application.", "author_names": [ "Renuka Chinchwadkar", "Vaishali V Ingale", "Ashlesha Gokhale" ], "corpus_id": 226496405, "doc_id": "226496405", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Hardware Implementation of Histogram Based Algorithm for Image Enhancement", "venue": "", "year": 2020 }, { "abstract": "Major operation block in any processing unit is a multiplier. There are many multiplication algorithms are proposed, by using which multiplier structure can be designed. Among various multiplication algorithms, Wallace tree multiplication algorithm is beneficial in terms of speed of operation. With the advancement of technology, demand for circuits with high speed and low area is increasing. In order to improve the speed of Wallace tree multiplier without degrading its area parameter, a new structure of Wallace tree multiplier is proposed in this paper. In the proposed structure, the final addition stage of partial products is performed by parallel prefix adders (PPAs) In this paper, five Wallace tree multiplier structures are proposed using Kogge stone adder, Sklansky adder, Brent Kung adder, Ladner Fischer adder and Han carlson adder. All the multiplier structures are designed using Verilog HDL in Xilinix 13.2 design suite. The proposed structures are simulated using ISIM simulator and synthesized using XST synthesizer. The proposed designs are analyzed with respect to traditional multiplier design in terms of area (No. of LUTs) and delay (ns)", "author_names": [ "Yamini devi Ykuntam", "Katta Pavani", "Krishna Saladi" ], "corpus_id": 224778164, "doc_id": "224778164", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design and analysis of High speed wallace tree multiplier using parallel prefix adders for VLSI circuit designs", "venue": "2020 11th International Conference on Computing, Communication and Networking Technologies (ICCCNT)", "year": 2020 }, { "abstract": "Reversible logic is considered to be a major promising alternative to traditional digital logic circuits. It eliminates the possibility of information loss and makes the system run in the backward direction there by allowing the recovery of the inputs from the generated outputs. Converting an image from RGB to gray scale is crucial for majority of the image and video processing applications and also various computer vision applications as they reduce the computational complexity, storage space and increase the system speed. In this paper we have proposed three efficient reversible logic based schemes for the implementation of the color space converter units. We have implemented the RGB to gray scale converter units using three different techniques namely average method, desaturation and luminosity methods. The implementation of the proposed design and its functionality verification was done on XILINX 14.7 ISE and using Verilog HDL. The proposed design finds applications in many of the fields including image processing, video processing and high speed low power digital signal processing applications as well as computer vision applications like face gesture recognition, object detection, traffic monitoring systems and surveillance systems.", "author_names": [ "Swathi U", "Smitha U" ], "corpus_id": 229358301, "doc_id": "229358301", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Design and Implementation of Efficient RGB to Gray scale Converter Architectures Using Reversible Logic", "venue": "2020 IEEE International Conference on Distributed Computing, VLSI, Electrical Circuits and Robotics (DISCOVER)", "year": 2020 }, { "abstract": "A radiation induced single event upset (SEU) is a major disruption to electronics operating in satellites. If not rectified, a single bit error can become uncorrectable. In this paper, we present two interleaved Double Adjacent Error Corrections (DAECs) for Error Detection and Correction (EDAC) using the Hsiao Code and Cyclic Redundancy Code (CRC) From our results, both EDACs can correct 100% of the single bit errors, double adjacent bit errors, and detect double bit errors and up to four adjacent bit errors. The Hsiao Code EDAC encoder design requires less bit weight than the CRC EDAC, which is an attribute of a high speed EDAC. The CRC EDAC, in contrast, has a higher error detection rate for both three and four bit errors, at 96.25% and 91.92% respectively. We also propose two storage formats and algorithm designs that can manage and store the 48 bit codeword in 8 bit and 16 bit memory devices, a typical satellite scenario where board space is scarce. We used Verilog HDL, C+ and ModelSim to create and test our designs.", "author_names": [ "Mong Tee Sim", "Yanyan Zhuang" ], "corpus_id": 227062296, "doc_id": "227062296", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design of Two Interleaved Error Detection and Corrections using Hsiao Code and CRC", "venue": "IECON 2020 The 46th Annual Conference of the IEEE Industrial Electronics Society", "year": 2020 }, { "abstract": "The power efficiency of hardware circuits is of paramount importance for constructing embedded electronic devices, as it is one of the major design constraints in today's embedded systems, limiting performance, battery life, etc. This thesis targets the power efficiency in hardware circuits with symbolic discrete control. In the research proposed in this thesis, we consider hardware circuits, described using the popular Hardware DescriptionLanguage (HDL) Verilog, at the Register transfer Level (RTL) abstraction, as hierarchical compositions of sub circuits. We achieve power efficiency by switching off the clock of each sub circuit according to some clock gating logic, where the technique applied is known as RTL clock gating, which is one of the best low power technique applied on synchronous hardware circuits. We advance the following approaches in order to produce a clock gating logic: to switchoff the clock signal of a sub circuit in the idle status, which is a set of values of the circuit signals when the values of the memory components do not change; to apply power aware scheduling policies for data flow hardware circuits implemented as Kahn Process Networks (KPNs) using the clock gating logic as used to selectively filter the clocks of the sub circuits involved; and to employ an energy efficient configuration manager for choosing the optimal configuration, by means of the clock gating logic, among the alternatives on data flow hardware circuits implemented as KPN, with parallel synchronous processes. We devise a tool supported framework for achieving power efficiency of hardware circuits for each approach. Our approaches rely on formal control techniques, where the goal is to compute a strategy that can be used to drive a given model so that it satisfies a set of control objectives. More specifically, we give an algorithm that derives abstract behavioral models directly in a symbolic form from original designs, and for formulating suitable constraints and objectives. We encode the computation of the latter as several small symbolic Discrete ControllerSynthesis (DCS) problems, and use the resulting controllers to derive power efficient versions from original circuit designs. Finally, we show how a resulting strategy can be translated into a piece of synchronous circuit that, when paired with the original design, ensures the aforementioned objectives. We detail and illustrate our approaches using various hardware designs and objectives, and validate them experimentally by deriving a low power version of the original hardware designs.", "author_names": [ "Mete Ozbaltan" ], "corpus_id": 219872862, "doc_id": "219872862", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Achieving power efficiency in hardware circuits with symbolic discrete control", "venue": "", "year": 2020 }, { "abstract": "This paper presents the analysis of various architectures of Low power FFT Processors. FFT is a major building block in DSP and communication system. FFT is an efficient way to implement DFT in a faster manner. Using FFT the number of multiplication and addition order O(N/2log2N) and O(Nlog2N) are reduced. Conventional FFT has more chip area and delay. Hence pipelined FFT is preferred to overcome the demerits of the conventional processor. This paper reports a detailed study of various FFT architectures and mainly about R22SDF SDF FFT. In this paper, to reduce delay an advanced design of 64 point Pipelined Radix 22 Single Path Delay Feedback (R22SDF) FFT architecture has been proposed by using Verilog Hardware Description Language (Verilog HDL) The simulation results has been evaluated by using Modelsim 6.3C and synthesis results are estimated by using Xilinx Planahead 12.4i design tool.", "author_names": [ "C Ramesh Kumar", "M P Chitra" ], "corpus_id": 221913326, "doc_id": "221913326", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Implementation of Area Efficient Pipelined R22SDF FFT Architecture", "venue": "2020 7th International Conference on Smart Structures and Systems (ICSSS)", "year": 2020 }, { "abstract": "Abstract In processors the complex and challenging operations are needed to be handled to overcome the demands, which leads to an increase in processor cores. This leads to an increase in the load of the processor and can be limited by placing a co processors under specific type of functions like signal processing. But anyhow the speed of the ALU replies on the multiplier. Since multipliers are the major components to perform operations in the CPU. To implement fast multiplication operations, Vedic mathematics are involved based on 16 sutras, each with its special characteristics. This technique usually reduces the area, power and delay of the processors. So the existing Wallace tree multiplier technique has been replaced by the Vedic multiplier algorithms based on two different sutras as Urdhva Tiriyagbhyam and Nikhilam algorithms. These types of multipliers were designed and specified using Verilog HDL and have been synthesized and simulated using Xilinx ISE project Navigator v. 14. 7 platform and then compared with the parameters like delay time, area (Number of sliced LUT's and Number of bonded IOB's) and power in 32, 64 and 128 binary bit multiplication", "author_names": [ "M Kivi Sona", "V Somasundaram" ], "corpus_id": 219882302, "doc_id": "219882302", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Vedic Multiplier Implementation in VLSI", "venue": "", "year": 2020 }, { "abstract": "Prevalent hardware description languages (HDLs) e.g. Verilog and VHDL, employ register transfer level (RTL) as their underlying programming model. One major downside of the RTL model is that it tightly couples design functionality with timing and device constraints. This coupling increases code complexity and yields code that is more verbose and less portable. High level synthesis (HLS) tools decouple functionality from timing and design constraints by utilizing constructs from imperative programming languages. These constructs and their sequential semantics, however, impede construction of inherently parallel hardware and data scheduling, which is crucial in many design use cases. In our work we present a novel dataflow hardware description abstraction layer as basis for hardware design and apply it to DFiant, a Scala embedded HDL. DFiant leverages dataflow semantics along with modern software language features (e.g. inheritance, polymorphism) and classic HDL traits (e.g. bit accuracy, input/output ports) to decouple functionality from implementation constraints. Therefore, DFiant designs are timing agnostic and device agnostic and can be automatically pipelined by the DFiant compiler to meet target performance requirements. With DFiant we demonstrate how dataflow HDL code can be substantially more portable and compact than its equivalent RTL code, yet without compromising its target design performance.", "author_names": [ "Oron Port", "Yoav Etsion" ], "corpus_id": 211521283, "doc_id": "211521283", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Hardware Description Beyond Register Transfer Level Languages", "venue": "FPGA", "year": 2020 }, { "abstract": "Airborne Ad hoc Networks (AANETs) are a subclass of Vehicular Ad hoc Networks (VANETs) The major challenge in AANET implementation is the regular route breaks due to very high mobility of aircraft. To deal with this routing challenge in AANETs, we have designed a new protocol named Airborne OLSR (AOLSR) which is based on more optimisation of the MPR selection technique used in existing OLSR protocol. A hardware implementation of any protocol is always crucial for the validation of its design. So, this manuscript also provides a hardware implementation of both OLSR and AOLSR protocols using Verilog. The node architectures for both the protocols have been implemented in Vivado. The node's sub component implementation area, execution time and total power consumption have been used as parameters to compare their performance. The simulation analysis shows that the proposed AOLSR performs better as compared to OLSR in terms of total power consumption and execution time.", "author_names": [ "Pardeep Kumar", "Seema Verma" ], "corpus_id": 226614463, "doc_id": "226614463", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Hardware implementation of OLSR and improved OLSR (AOLSR) for AANETs", "venue": "", "year": 2020 } ]
High power laser direct modulation
[ { "abstract": "The direct modulation of high power semiconductor laser driver that is composed of the current modulation circuit and the over current protection circuit is introduced, two direct modulation circuits with different modulation output current amplitude are designed and the direct modulation of characteristics is analyzed, providing the output current waveform of the direct modulation of high power semiconductor laser. In this paper, a new modulation output current with a peak current of 9.5A is designed with bias current of 0.8A and the modulation current bandwidth of 2.56MHz. The width of the modulation current pulse keeps stable after widening. When the input signal is voltage pulse with uniform pulse width, it can output current pulse with uniform pulse width. And the modulation output current with a peak current of 9.5A is designed with bias current of 0.8A and the modulation current bandwidth of 5MHz. We have a theoretical study on the dynamic characteristics of direct modulation of semiconductor laser. We also have done some experiments on the basis of the simulation, the experimental results show that the output pulse laser intensity and the pulse laser modulation signal width change with changing the width of the pulse, and the actual modulated output pulse laser has a certain time delay with respect to the modulated signal.", "author_names": [ "Weipeng Wang", "Yingtian Xu", "Xiaohui Ma", "Yong-gang Zou", "Linbao Hou", "Li Han", "Yulong Wu", "Dan Wang", "Lushuang Ding" ], "corpus_id": 34788747, "doc_id": "34788747", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Study on the direct modulation characteristics of high power semiconductor laser", "venue": "2015 International Conference on Optoelectronics and Microelectronics (ICOM)", "year": 2015 }, { "abstract": "95oC, 25 Gbps direct modulation of a high power (15mW) 1.3 um InGaAIAs DFB laser is developed for the first time. The device will be a key for 4 channel CWDM uncooled light sources used in the lower power consumption 100 GbE subsystems.", "author_names": [ "T Fukamachi", "Takashi Shiota", "Katsuji Haibara-gun Kitatani", "Takuma Ban", "Yasunobu Matsuoka", "Reiko Mita", "Toshiki Sugawara", "S Tanaka", "Kazunori Shinoda", "Koichiro Adachi", "Masahiro Aoki" ], "corpus_id": 38417836, "doc_id": "38417836", "n_citations": 15, "n_key_citations": 0, "score": 1, "title": "95 oC uncooled and high power 25 Gbps direct modulation of InGaAlAs ridge waveguide DFB laser", "venue": "2009 35th European Conference on Optical Communication", "year": 2009 }, { "abstract": "Aiming to realize high speed optical transmitters for isolator free telecommunication systems, 1.3 mm p modulation doped InGaAs/GaAs quantum dot (QD) lasers with a 400 mm long cavity have been reported. Compared with the un doped QD laser as a reference, the p doped QD laser emits at ground state, with an ultra low threshold current and a high maximum output power. The p doped QD laser also shows enhanced dynamic characteristics, with a 10 Gb/s large signal direct modulation rate and a 7.8 GHz 3dB bandwidth. In addition, the p doped QD laser exhibits a strong coherent optical feedback resistance, which might be beyond 9 dB.", "author_names": [ "Xia-Yida MaXueer", "Yiming He", "Zunren Lv", "Zhongkai Zhang", "Hongyu Chai", "Dan Lu", "Xiao-Guang Yang", "Tao Yang" ], "corpus_id": 228949785, "doc_id": "228949785", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "1.3 mm p Modulation Doped InGaAs/GaAs Quantum Dot Lasers with High Speed Direct Modulation Rate and Strong Optical Feedback Resistance", "venue": "", "year": 2020 }, { "abstract": "We report a high modulation efficiency two electrode tapered laser with a record 0.81 W output optical modulation amplitude for 70 mA applied current swing under 700 Mb/s direct modulation. In addition the device shows a record 40.5 W/A static modulation efficiency.", "author_names": [ "C H Kwok", "Mo Xia", "Richard Vincent Penty", "Ian H White", "Nicolas Michel", "Mike Ruiz", "Michel Krakowski", "Michel Calligaro", "Michel Lecomte", "Olivier Parillaud", "H Odriozola", "J M Garcia-Tijero", "Ignacio Esquivias" ], "corpus_id": 10326702, "doc_id": "10326702", "n_citations": 7, "n_key_citations": 2, "score": 0, "title": "Two electrode high power tapered laser with up to 40.5 W/A static modulation efficiency and 700 Mb/s direct modulation capability", "venue": "2009 Conference on Optical Fiber Communication incudes post deadline papers", "year": 2009 }, { "abstract": "An integrated laser source to a silicon photonics circuit is an important requirement for optical interconnects. We present direct modulation of a heterogeneously integrated distributed feedback laser on and coupled to a silicon waveguide. We demonstrate a 28 Gb/s pseudo random bit sequence non return to zero data transmission over 2 km non zero dispersion shifted fiber with a 1 dB power penalty. Additionally, we show 40 Gb/s duobinary modulation generated using the bandwidth limitation of the laser for both back to back and fiber transmission configurations. Furthermore, we investigate the device performance for the pulse amplitude modulation (PAM 4) at 20 GBd for high speed short reach applications.", "author_names": [ "Amin Abbasi", "Christos Spatharakis", "Giannis Kanakis", "Nuno Sequeira Andre", "Hadrien Louchet", "Andrew Katumba", "Jochem Verbist", "Hercules Avramopoulos", "Peter Bienstman", "Xin Yin", "Johan Bauwelinck", "Gunther Roelkens", "Geert Morthier" ], "corpus_id": 28718724, "doc_id": "28718724", "n_citations": 26, "n_key_citations": 1, "score": 1, "title": "High Speed Direct Modulation of a Heterogeneously Integrated InP/SOI DFB Laser", "venue": "Journal of Lightwave Technology", "year": 2016 }, { "abstract": "We demonstrate high speed data transmission with a commercial high power GaN laser diode at 450 nm. 2.6 GHz bandwidth was achieved at an injection current of 500 mA using a high speed visible light communication setup. Record high 4 Gbps free space data transmission rate was achieved at room temperature.", "author_names": [ "Chang-Mi Lee", "Chong Zhang", "Michael Cantore", "Robert Michael Farrell", "Sang Ho Oh", "Tal Margalith", "James S Speck", "Shuji Nakamura", "John E Bowers", "Steven P Denbaars" ], "corpus_id": 35597837, "doc_id": "35597837", "n_citations": 106, "n_key_citations": 7, "score": 1, "title": "4 Gbps direct modulation of 450 nm GaN laser for high speed visible light communication.", "venue": "Optics express", "year": 2015 }, { "abstract": "Multi band power allocation for NG PON downlink transmission is experimentally demonstrated when implementing AMOOFDM with direct modulation of a linear laser. Multi user power and bit allocation allows the users datarates to be balanced according to a target QoS.", "author_names": [ "Ahmed Gharba", "Meryem Ouzzif", "Jerome Le Masson", "Philippe Chanclou", "Naveena Genay", "Benoit Charbonnier", "Emmanuel Grard", "V Rodrigues", "T Duong", "Maryline Helard" ], "corpus_id": 43342785, "doc_id": "43342785", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Multi band power allocation in AMOOFDM high data rate NG PON downlink transmission direct modulation of linear laser", "venue": "2010 Conference on Optical Fiber Communication (OFC/NFOEC) collocated National Fiber Optic Engineers Conference", "year": 2010 }, { "abstract": "We demonstrate high speed data transmission with a commercial high power GaN laser diode at 450 nm. 2.6 GHz bandwidth was achieved at an injection current of 500 mA using a high speed visible light communication setup. Record high 4 Gbps free space data transmission rate was achieved at room temperature. (c)2015 Optical Society of America OCIS codes: (060.2605) Free space optical communication; (060.4080) Modulation; (140.7300) Visible lasers; (250.5960) Semiconductor lasers. References and links 1. S. Nakamura, M. Senoh, and T. Mukai, \"P GaN/N InGaN/N GaN double heterostructure blue light emitting diodes,\" Jpn. J. Appl. Phys. 32(2) L8 L11 (1993) 2. S. Pimputkar, J. S. Speck, S. P. DenBaars, and S. Nakamura, \"Prospects for LED lighting,\" Nat. Photonics 3(4) 180 182 (2009) 3. L. Grobe, A. Paraskevopoulos, J. Hilt, D. Schulz, F. Lassak, F. Hartlieb, C. Kottke, V. Jungnickel, and K. Langer, \"High speed visible light communication systems,\" IEEE Commun. Mag. 51(12) 60 66 (2013) 4. J. D. McKendry, D. Massoubre, S. Zhang, B. R. Rae, R. P. Green, E. Gu, R. K. Henderson, A. E. Kelly, and M. D. Dawson, \"Visible light communications using a CMOS controlled micro light emitting diode array,\" J. Lightwave Technol. 30(1) 61 67 (2012) 5. S. Zhang, S. Watson, J. McKendry, D. Massoubre, A. Cogman, E. Gu, R. K. Henderson, A. E. Kelly, and M. D. Dawson, \"1.5 Gbit/s multi channel visible light communications using CMOS controlled GaN based LEDs,\" J. Lightwave Technol. 31(8) 1211 1216 (2013) 6. J. D. McKendry, R. P. Green, A. E. Kelly, Z. Gong, B. Guilhabert, D. Massoubre, E. Gu, and M. D. Dawson, \"High speed visible light communications using individual pixels in a micro light emitting diode array,\" IEEE Photon. Technol. Lett. 22(18) 1346 1348 (2010) 7. S. Zhang, S. Watson, J. McKendry, D. Massoubre, A. Cogman, E. Gu, R. K. Henderson, A. E. Kelly, and M. D. Dawson, \"1.5 Gbit/s multi channel visible light communications using CMOS controlled GaN based LEDs,\" J. Lightwave Technol. 31(8) 1211 1216 (2013) 8. D. Tsonev, H. Chun, S. Rajbhandari, J. McKendry, S. Videv, E. Gu, M. Haji, S. Watson, A. E. Kelly, G. Faulkner, M. D. Dawson, H. Haas, and D. O'Brian, \"3 Gb/s single LED OFDM based wireless VLC link using a gallium nitride mLED,\" IEEE Photon. Technol. Lett. 26(7) 637 640 (2014) 9. H. Chun, P. Manousiadis, S. Rajbhandari, D. A. Vithanage, G. Faulkner, D. Tsonev, J. D. McKendry, S. Videv, E. Xie, E. Gu, M. D. Dawson, H. Haas, G. A. Turnbull, I. D. Samuel, and D. O'Brian, \"Visible light communication using a blue GaN mLED and fluorescent polymer color converter,\" IEEE Photon. Technol. Lett. 26(20) 1041 1135 (2014) 10. D. Tsonev, S. Videv, and H. Haas, \"Towards a 100 Gb/s visible light wireless access network,\" Opt. Express 23(2) 1627 1637 (2015) 11. S. Watson, M. Tan, S. P. Najda, P. Perlin, M. Leszczynski, G. Targowski, S. Grzanka, and A. E. Kelly, \"Visible light communications using a directly modulated 422 nm GaN laser diode,\" Opt. Lett. 38(19) 3792 3794 (2013) 12. K. A. Denault, M. Cantore, S. Nakamura, S. P. DenBaars, and R. Seshadri, \"Efficient and stable laser driven white lighting,\" AIP Adv. 3(7) 072107 (2013) 13. J. E. Bowers, \"High speed semiconductor laser design and performance,\" Solid State Electron. 30(1) 1 11 (1987) 14. L. A. Coldren, S. W. Corzine, and M. L. Mashanovitch, Diode Lasers and Photonic Integrated Circuits, 2nd ed. (Wiley Interscience, 2012) #237857 $15.00 USD Received 13 Apr 2015; revised 23 May 2015; accepted 25 May 2015; published 10 Jun 2015 (C) 2015 OSA 15 Jun 2015 Vol. 23, No. 12 DOI:10.1364/OE.23.016232 OPTICS EXPRESS 16232", "author_names": [ "Chang-Mi Lee", "Chong Zhang", "Michael Cantore", "Robert Michael Farrell", "Sang Ho Oh", "Tal Margalith", "James S Speck", "Shuji Nakamura", "John E Bowers", "Steven P Denbaars" ], "corpus_id": 28702239, "doc_id": "28702239", "n_citations": 10, "n_key_citations": 1, "score": 0, "title": "Gbps direct modulation of 450 nm GaN laser for high speed visible light communication", "venue": "", "year": 2015 }, { "abstract": "Terahertz communication technology can provide abundant frequency resources, strong confidentiality, antijamming capability, communication tracking capability and the ability to achieve highspeed data transmissions and can serve as an important technical method for high speed communications in the future. Among these terahertz communication technologies, terahertz direct modulation technology is a key means to achieve low system complexity and power consumption. In this paper, a review and outlook of terahertz direct modulation technology are proposed from the aspects of high electron mobility transistor based terahertz direct modulation, parallelswitch terahertz direct modulation, diode based terahertz direct modulation, quantum cascade laser based terahertz direct modulation and new material based terahertz direct modulation. We hope through this paper that more readers can gain knowledge about the development and challenges of terahertz direct modulation technology for high speed communication systems, thus promoting the development of high speed terahertz communication technology based on direct modulation.", "author_names": [ "Tianchi Zhou", "Yaxin Zhang", "Hongxin Zeng", "Zhiyong Tan", "Xilin Zhang", "Lan Wang", "Zhi Chen", "Juncheng Cao", "Kaijun Song", "Ziqiang Yang" ], "corpus_id": 235235562, "doc_id": "235235562", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Terahertz direct modulation techniques for high speed communication systems", "venue": "China Communications", "year": 2021 }, { "abstract": "We investigated the limitations in output power generated by a high power narrow linewidth Raman fiber amplifier. The pump was produced by a kW level all fiber Yb doped amplifier emitting at 1060 nm, whose seed linewidth could be changed. The Raman seed was a narrow linewidth signal at 1110 nm co propagating with the laser at 1060 nm. The main Raman conversion occurred in the passive fiber at the amplifier output. We identified cross phase modulation (XPM) as a main reason for broadening of the Raman light by using different pump sources, which is a first limitation. An improved setup was limited at approximately 600 W of Stokes output power by a threshold like onset of a transverse mode instability. Since the instability was not observed without a Stokes seed and the temperatures of the active fiber with and without Stokes seed are equal, this constitutes the first direct observation of transverse mode instabilities (TMI) induced by SRS in a passive fiber.", "author_names": [ "Victor Distler", "Friedrich Moller", "Maximilian Strecker", "Gonzalo Palma-Vega", "Till Walbaum", "Thomas Schreiber", "Andreas Tunnermann" ], "corpus_id": 214238362, "doc_id": "214238362", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "High power narrow linewidth Raman amplifier and its limitation", "venue": "LASE", "year": 2020 } ]
Al doped film photodetector
[ { "abstract": "Ultraviolet (UV) detection properties of undoped ZnO and Al doped ZnO (AZO) based interdigitated metal semiconductor metal (MSM) structure are investigated in this paper. High quality of fibrous Al doped ZnO thin films with enhanced conductivity and optical response with controlled doping of Al are synthesized using low cost sol gel method. The surface morphology and absorption properties of the films have been investigated. The responsivity and detectivity characteristics of both the devices are compared over 300 700 nm wavelengths. The Al doped ZnO based Ag/AZO/Ag MSM structure show the maximum responsivity and detectivity of ~5.63 A/W and <inline formula> <tex math notation=\"LaTeX\"\\sim 1.8\\times 10 {12} /tex math>/inline formula> cmHz<sup>1/2</sup>W<sup> 1</sup> while the respective values for the Ag/undoped ZnO/Ag photodetector are ~3.65 A/W and <inline formula> <tex math notation=\"LaTeX\"\\sim 1.3\\times 10 {12} /tex math>/inline formula> cmHz<sup>1/2</sup>W<sup> 1</sup> at 365 nm and <inline formula> <tex math notation=\"LaTeX\"$34~\\mu \\text{W} /tex math>/inline formula>/cm<sup>2</sup> incident UV intensity. The proposed AZO based MSM photodetector has smaller rise time ~30 s) than that ~35 s) of the undoped ZnO based MSM photodetector. However, the AZO based device shows slightly poor spectrum selectivity over the undoped ZnO based device.", "author_names": [ "Chandan Kumar", "Bhoopendra Kumar Kushwaha", "Amit Kumar", "Deepak Kumar Jarwal", "Rishibrind Kumar Upadhyay", "Abhinav Pratap Singh", "Satyabrata Jit" ], "corpus_id": 211684320, "doc_id": "211684320", "n_citations": 19, "n_key_citations": 0, "score": 1, "title": "Fibrous Al Doped ZnO Thin Film Ultraviolet Photodetectors With Improved Responsivity and Speed", "venue": "IEEE Photonics Technology Letters", "year": 2020 }, { "abstract": "Abstract This paper presents the synthesis of undoped and 2 wt. titanium (Ti) doped zinc oxide (ZnO) thin films onto glass substrates by chemical spray pyrolysis technique. Both films are deposited at 375 degC substrate temperature. The influence of Ti doping on structural, morphological, optical and UV detection properties of ZnO film was studied. Both films revealed to be of polycrystalline nature with a hexagonal wurtzite structure; and the ZnO film crystallinity improved on Ti doping. Surface morphological observations agreed well with structural results. The Ti incorporation in ZnO thin films were confirmed by an energy dispersive X ray spectroscopic analysis (EDX) The Ti doping increased the optical transmittance ~96% at 550) and band gap ~3.2927 eV) of ZnO thin film. Further, the metal semiconductor metal (MSM) planar ultraviolet photodetectors (UV PDs) were fabricated from deposition of tin (Sn) contacts onto undoped and Ti doped ZnO films using e beam evaporation technique. To investigate UV photodetection properties, the MSM devices were subjected to current voltage (I V) characteristics measurements of forward and reverse bias in dark and UV light conditions. The photocurrent and responsivity were measured as a function of optical power density and applied voltage, respectively. The reproducibility of the UV detection performance of MSM devices was ensured by constantly switching UV light on and off at regular time intervals. The Ti doped ZnO film based UV PD demonstrates highest responsivity of about 0.051 A/W upon 2 mW/cm2 illumination at 365 nm peak wavelengths and 5 V applied bias.", "author_names": [ "Prashant Shivaji Shewale", "N K Lee", "Seung Hee Lee", "Kwang-yong Kang", "Y Shane Yu" ], "corpus_id": 137191320, "doc_id": "137191320", "n_citations": 59, "n_key_citations": 1, "score": 0, "title": "Ti doped ZnO thin film based UV photodetector: Fabrication and characterization", "venue": "", "year": 2015 }, { "abstract": "Abstract An n ZnO nanorods/ p Si heterojunction photodetector with Al doped ZnO (AZO) as an electron transporting layer was fabricated. The heterojunction with 20 nm AZO film showed a better characteristic than that of the device without AZO, and it displays a rectification ratio of 8470 at 3 V and a turn on voltage of 1.8 V. Also, based on spectral responsivity measurement, the device with AZO coating showed higher responsivity and better visible blind detectivity than those without AZO, and the peak responsivity of the photodetector with AZO was as high as ~0.49 A/W at 354 nm. Furthermore, the photodetector with AZO layer showed a bigger UV visible responsivity ratio R 354 nm R 546 nm than that of the photodetector without AZO coating at 2 V. The role of AZO layer was illustrated through energy band theory and the electron transport mechanism.", "author_names": [ "Hai Zhou", "Jun Mei", "Pengbin Gui", "Pan Tao", "Zehao Song", "Hao Wang", "Guojia Fang" ], "corpus_id": 94898261, "doc_id": "94898261", "n_citations": 27, "n_key_citations": 0, "score": 0, "title": "The investigation of Al doped ZnO as an electron transporting layer for visible blind ultraviolet photodetector based on n ZnO nanorods/p Si heterojunction", "venue": "", "year": 2015 }, { "abstract": "A Sb doped ZnO microrod array was fabricated on an Al doped ZnO thin film by electrodeposition. Strong violet luminescence, originated from free electron to acceptor level transitions, was identified by temperature dependent photoluminescence measurements. This acceptor related transition was attributed to substitution of Sb dopants for Zn sites, instead of O sites, to form a complex with two Zn vacancies (VZn) the SbZn 2VZn complex. This SbZn 2VZn complex has a lower formation energy and acts as a shallow acceptor which can induce the observed strong violet luminescence. The photoresponsivity of our ZnO p n homojunction device under a negative bias demonstrated a nearly 40 fold current gain, illustrating that our device is potentially an excellent candidate for photodetector applications in the ultraviolet wavelength region.", "author_names": [ "Wei-Jen Chen", "Jen-Kai Wu", "Jheng-Cyuan Lin", "Shun-Tsung Lo", "Huang De Lin", "D R Hang", "Ming-feng Shih", "Chi-Te Liang", "Yuan Huei Chang" ], "corpus_id": 1641084, "doc_id": "1641084", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Room temperature violet luminescence and ultraviolet photodetection of Sb doped ZnO/Al doped ZnO homojunction array", "venue": "Nanoscale Research Letters", "year": 2013 }, { "abstract": "ZnO and Al doped ZnO (AZO) thin films were grown on the ZnO buffer layer by a chemical spray pyrolysis method. The metal semiconductor metal (MSM) UV photodetector based on ZnO thin films with two device configuration Ag/AZO/ZnO/Ag and Ag/ZnO/ZnO/Ag have been studied. AZO and ZnO thin films were grown on the ZnO buffer layer by a chemical spray pyrolysis technique. The effect of the buffer layer on the physicochemical and UV sensing properties of the AZO and ZnO thin film based UV photodetectors were analyzed. The XRD results suggested that the buffer layer improves the crystalline quality of the ZnO thin films. The device with configuration Ag/AZO/ZnO/Ag exhibits a maximum photocurrent of about 876 uA at 5 V bias at 365 nm peak wavelength. The linear I V characteristic of the photodetector reveals the good ohmic contacts between metal semiconductor junctions. The AZO based UV photodetector with ZnO buffer layer shows a maximum photoresponsivity of about 340 A/W, which is much higher than that of the ZnO based UV photodetector with ZnO buffer layer. The photoresponse and photoswitching characteristics of the device demonstrate that a ZnO UV photodetector with a buffer layer offers a new way to fabricate devices on a buffer layer coated substrate.", "author_names": [ "S I Inamdar", "V V Ganbavle", "Sohel Khalil Shaikh", "K Y Rajpure" ], "corpus_id": 120252073, "doc_id": "120252073", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Effect of the buffer layer on the metal semiconductor metal UV photodetector based on Al doped and undoped ZnO thin films with different device structures", "venue": "", "year": 2015 }, { "abstract": "Abstract The structural, optical, and electrical properties of undoped and Al doped ZnO films deposited on p Si (001) substrate were studied using DC unbalanced magnetron sputtering. This study is motivated by the absence of detail reports concerning the orbital states inducing the optical bandgap (Eg) blueshift. Besides, the influences of Al on the possible modification of point defect and the photodetecting performance are highlighted to offer guidelines for better development in ZnO based photodetector. It was found that the Al doping reduced the grain size. The doping increased the lattice parameters and slightly decreased the local symmetry distortion at ZnO4. From the absorbance spectra, the doping increased Eg of ZnO film (3.28 3.36 eV) induced by the Burstein Moss effect. From the density functional calculation, the Burstein Moss effect induced Eg from the valence band maximum (VBM) to Fermi level located above the lowest Zn 4s conduction state. From the photoluminescence spectra, the undoped film showed the transitions from O vacancy, Zn interstitial, and free exciton states to the VBM. The doped film showed the transitions from Zn interstitial to O interstitial and few Zn vacancy states at the cost of O vacancies. Moreover, the energy level of free exciton states slightly decreased. Notably, O interstitials increased the lattice parameters. From the electrical properties, the doping enhanced the ultraviolet region photo to dark current ratio up to 3.044 V, leading to the photodetecting sensitivity enhancement. This study emphasizes the significant effect of Al doping on the optical absorbance, point defect evolution, and photodetecting performance of ZnO film for low voltage ultraviolet photodetector applications.", "author_names": [ "Ni'matul Azizah", "Shibghatullah Muhammady", "Muhammad Abiyyu Kenichi Purbayanto", "Eka Nurfani", "Toto Winata", "Euis Sustini", "Rena Widita", "Yudi Darma" ], "corpus_id": 214515767, "doc_id": "214515767", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Influence of Al doping on the crystal structure, optical properties, and photodetecting performance of ZnO film", "venue": "", "year": 2020 }, { "abstract": "The maximum of spectral sensitivity of ZnO based photodetectors can be shifted to deep UV photon range of ~250 to 300 nm by Mg dosing [1, 2] However heavily Mg doped ZnO shows very poor conductance and optical properties, which limits its use as a sensitive element of deep UV SAW photodetector. The simultaneously doped ZnO by Mg and Al atoms may assist in tuning electrical, optical and structural properties of ZnO in wide range and opens the possibility to use Zn1 x yMgxAlyO films for deep UV detector integrated to SAW device. Apart from dopant related aspects the structural and optical quality of a film prepared by PLD method is heavily influenced by the film/nanostructure growth temperature and oxygen pressure. We study optical, structural, lattice vibration modes and photoelectric properties of Zn1 x yMgxAlyO films on LiNbO3 substrates designed by PLD method at different oxygen pressure and growth temperatures to optimize their properties for using as a deep UV sensitive element of surface acoustic wave (SAW) photodetector. The optical absorption band edge for optimized Zn0.52Mg0.19Al0.007O/LiNbO3 film was shifted to 320 nm and the corresponding photodetector demonstrates high sensitivity and fast photoelectric response towards 248 nm laser light.", "author_names": [ "M E Kutepov", "Vladimir E Kaydashev", "G Ya Karapetyan", "D A Zhilin", "Tatevik Minasyan", "A S Anokhin", "Anatoly Chernyshev", "Kamaludin Abdulvakhidov", "Ekaterina Glazunova", "Vladimir Irkha", "E M Kaidashev" ], "corpus_id": 198404341, "doc_id": "198404341", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Optimization of Zn 1 x y Mg x Al y O Film Properties to Use in Deep UV SAW Photodetector", "venue": "", "year": 2019 }, { "abstract": "Abstract The Cu 2 O films were electrodeposited on ZnO nanorod arrays (NRs) and the Cu 2 O/ZnO NRs heterojunctions were formed. The optical electronic response of the heterojunctions was investigated. The diameter size and crystal quality of ZnO NRs were modified by the seed layer. ZnO NRs with good crystal quality were obtained on the 0.5% Al doped ZnO seed layer film (named as AZO (0.5% The devices based on the Cu 2 O/ZnO NRs heterojunction exhibit excellent stability and reproducibility of the self powered photoresponse properties. The device with AZO (0.5% seed layer demonstrates the high photoresponsivity of 60 70 mA/W in the violet and blue light with a fast response speed at zero applied bias.", "author_names": [ "Chang Wang", "Jianping Xu", "Shaobo Shi", "Yuzhu Zhang", "Yanyan Gao", "Zeming Liu", "Xuguang Zhang", "Lan Li" ], "corpus_id": 99224478, "doc_id": "99224478", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Optimizing performance of Cu2O/ZnO nanorods heterojunction based self powered photodetector with ZnO seed layer", "venue": "", "year": 2017 }, { "abstract": "Organic position sensitive detector (OPSD) based on copper phthalocyanine CuPc:fullerene C60 bulk heterojunction with an inverted structure have been fabricated using aluminum doped ZnO (ZnO:Al) as a resistive layer, which is prepared by sol gel method. The resistance length of the one dimensional PSD is fixed at 5 mm, and the Ag common electrode is fabricated by vacuum evaporation within the 100 um width. The current density voltage characteristics with different structures of photodetector, the influence of ZnO:Al resistivity on the thickness and the position characteristics of PSDs are investigated. The experimental results indicate that the architecture, which uses an inverted structure, increases sensitivity under red light illumination compared to the conventional structure. In addition, the thickness of the ZnO:Al has influence on the position characteristics. The resistivity of ZnO:A film with Al doping concentration of 2 mol% prepared in this study is around 150 Ocm and it increases from less than approximately 400 nm thickness. These characteristics seem to be correlated with the properties of ZnO:AI resistive layer. For a device with a 620 nm thick ZnO:Al layer, the measured position values obtained from the output photocurrent agree with the actual position values under red laser light illumination. CuPc:C60 OPSD with an inverted structure exhibits red light sensitivity, high incident photon to current conversion efficiency of above 80% at 3 V and linearity error of 5.9% at 2 V.", "author_names": [ "Taichiro Morimune", "Hirotake Kajii", "Hiroki Nishimaru", "Shinji Ono" ], "corpus_id": 1030256, "doc_id": "1030256", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Organic Position Sensitive Detectors Based on ZnO:Al and CuPc:C60.", "venue": "Journal of nanoscience and nanotechnology", "year": 2016 }, { "abstract": "Thin film heterojuction of the type p ZnO/n GaN was prepared by spray pyrolysis and electron beam evaporation technique, respectively. Hall measurements demonstrate the firm p type conductivity of the p doped ZnO film. The structural and electrical properties of the p ZnO/n GaN heterojunction are investigated by X ray diffraction (XRD) and current voltage (I V) measurements. The XRD shows that the p ZnO/n GaN heterojunction is highly crystalline in nature with preferred orientation along the [0001] direction. The current voltage curve of the heterojunction demonstrates obvious rectifying diode behavior in the dark and under illumination conditions. The ideality factor of the detector was determined in case of forward bias at low voltages and it was found to be 13.35. The turn on voltage appears at about 1V under forward biased voltage, and the reverse breakdown voltage is about 4V. It was found that the current of the illumination increases with the increase of bias voltages.", "author_names": [ "Abla Al-Zouhbi", "Nasser Saad Al-Din", "M O Manasreh" ], "corpus_id": 122557738, "doc_id": "122557738", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Characteristics of p ZnO/n GaN heterojunction photodetector", "venue": "", "year": 2012 } ]
Device electronics for integrated
[ { "abstract": "Semiconductor Electronics. Silicon Technology. Metal Semiconductor Contacts. pn Junctions. Currents in pn Junctions. Bipolar Transistors I: Basic Properties. Bipolar Transistors II: Limitations and Models. Properties of the Metal Oxide Silicon System. Mos Field Effect Transistors I: Physical Effects and Models. Mos Field Effect Transistors II: High Field Effects. Answers to Selected Problems. Selected List of Symbols. Index.", "author_names": [ "Richard S Muller", "Theodore I Kamins" ], "corpus_id": 106849895, "doc_id": "106849895", "n_citations": 1403, "n_key_citations": 62, "score": 1, "title": "Device Electronics for Integrated Circuits", "venue": "", "year": 1977 }, { "abstract": "", "author_names": [ "Contributors Patricia Veiga-Crespo" ], "corpus_id": 203039347, "doc_id": "203039347", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Device Electronics For Integrated Circuits", "venue": "", "year": 2018 }, { "abstract": "custom design. A chapter is devoted to VLSI architectures, and covers the implementation of finite state machines and the use of cellular logic to reduce complexity. This is followed by an introduction to digital signal processing, and descriptions of some typical signal processing architectures. Having done the groundwork, the author then presents three case studies of signal processing system designs. A digital finite impulse response filter is used to illustrate the basic approach to system design using the metrics introduced earlier. A frequency domain filter shows when to use semi custom VLSI circuits, and a digital beam former presents a case for full custom design. The tradeoffs between using commercial chips, and designing custom chips are discussed. Finally, the book ends with a look at networking, and a comparison of several interconnection schemes. The book is well structured with each chapter starting with a concise summary and finishing with a good reference list. It is aimed at graduate engineers, and forms a useful introduction to signal processing system design. M. J. NAYLOR, Department ofElectrical and Electronic Engineering, University ofCanterbury New Zealand", "author_names": [ "Laurence J Herbst" ], "corpus_id": 112341956, "doc_id": "112341956", "n_citations": 15, "n_key_citations": 2, "score": 0, "title": "Book Review: Device Electronics for Integrated Circuits, 2nd Ed.", "venue": "", "year": 1987 }, { "abstract": "Device Electronics for Integrated Circuits: RICHARD S. MULLER and THEODORE I. KAMINS (John Wiley, 1977,404 pp. PS14.70) This book is a scholarly contribution at an advanced standard on the physical principles of bipolar and MOS silicon devices. The first of the seven chapters covers the basic physics of semiconductors and also deals with the general principles of monolithic integrated circuit technology. The next chapter contains a detailed account of metal semiconductor contacts and gives a better insight into Schottky diodes and transistors than most other texts. Chapters 3 and 4 present a somewhat unusual division of pn junction diode descriptions into predominantly electrostatic effects (Chapter 3) and current flow (Chapter 4) the account reads well. Then come two chapters on bipolar transistors. The first goes into basic device operation and the second embraces performance at low and high currents, high level injection, the charge control and other models. The final two chapters cover MOS fundamentals and MOSFETs. The book is pitched at a level appropriate for Honours undergraduates specifically interested in semiconductor device fundamentals, and for research workers in that field. The more advanced sections of this already erudite contribution are specially marked, as are the more advanced of the well thought out numerous problems set at the end of each chapter. Although much of the material is relevant to integrated circuits, the book decidedly falls short of displaying anything like the closeness to ICs expected from its title. There could have been much more on actual IC device structures and the significance of the various established processing techniques for bipolar and MOS transistors. Nor is there enough coverage of resistors and capacitors. The treatment of MOSFETs lacks the depth of that on bipolar devices, although the authors state correctly that MOS are on par with bipolar ICs at present, and might even overtake them in the future. Another weakness is the treatment of frequency dependent device parameters, which, at an elementary level, is inadequate in respect of subject coverage and equivalent circuit modelling. In spite of these criticisms, the book can be strongly recommended to all those who seek a good rigorous grounding in active silicon semiconductor device operation. L. J. HERBST, Head ofDepartment ofElectrical, Instrumentation and Control Engineering, Teesside Polytechnic, Middlesbrough", "author_names": [ "Laurence J Herbst" ], "corpus_id": 116363356, "doc_id": "116363356", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Book Review: Device Electronics for Integrated Circuits", "venue": "", "year": 1979 }, { "abstract": "The demand for novel electronics that can monitor human health, for example, the physical conditions of individuals, during daily life using different techniques from those used in traditional clinic diagnostic facilities is increasing. These novel electronics include stretchable sensor devices that allow various biosignals to be directly measured on human skin without restricting routine activity. The thin, skin like characteristics of these devices enable stable operation under various deformations, such as stretching, pressing, and rubbing, experienced while attached to skin. The mechanically engineered design of these devices also minimizes the inconvenience caused by long term wear owing to conformal lamination on the skin. The final form of a skin attachable device must be an integrated platform with an independent and complete system containing all components on a single, thin, lightweight, stretchable substrate. To fabricate fully integrated devices, various aspects, such as material design for deformable interconnection, fabrication of high performance active devices, miniaturization, and dense arrangement of component devices, should be considered. In particular, a power supply system is critical and must be combined in an electromechanically stable and efficient manner with all devices, including sensors. Additionally, the biosignals obtained by these sensors should be wirelessly transmitted to external electronic devices for free daily activity. This Account covers recent progress in developing fully integrated, stretchable, skin attachable devices by presenting our strategies to achieve this goal. First, we introduce several integration methods used in this field to build stretchable systems with a special focus on the utilization of liquid gallium alloy. The unique characteristics and patterning process of liquid metal are summarized. Second, various skin attachable sensors, including strain, pressure, with enhanced sensitivity and mechanical properties are discussed along with their applications for biosignal monitoring. Dual mode sensors that simultaneously detect temperature and pressure signals without interference are also introduced. Third, we emphasize supercapacitors as promising, efficient energy storage devices for power management systems in wearable devices. Supercapacitors for skin attachable applications should have a high performance, such as high operation voltage, high energy and power densities, cyclic and air stability and water resistance. For this, strategies to select novel materials for electrode, electrolyte, and encapsulation are suggested. Several approaches to fabricate stretchable supercapacitor systems are also presented. Finally, we introduce recent examples of skin attachable, stretchable electronics that integrate sensors, power management devices, and wireless data transfer functions on a single elastomer substrate. Conventional wireless technologies, such as near field communications (NFC) and Bluetooth, are incorporated in miniaturized features on the devices. To date, much research has been performed in this field, but there are still many technologies to develop. The performance of individual devices and mass fabrication techniques should be enhanced. We expect that future electronic devices with fully integrated functions will include advanced human machine interaction capabilities and expand the overall abilities of the human body.", "author_names": [ "Yu Ra Jeong", "Geumbee Lee", "Heun Park", "Jeong Sook Ha" ], "corpus_id": 58564801, "doc_id": "58564801", "n_citations": 33, "n_key_citations": 0, "score": 0, "title": "Stretchable, Skin Attachable Electronics with Integrated Energy Storage Devices for Biosignal Monitoring.", "venue": "Accounts of chemical research", "year": 2019 }, { "abstract": "being converged with artificial intelligence (AI) by providing users' biological and behavioral signals collected in wearable biodevices,[21 31] offering intelligent services based on big data cloud computing and machine learning.[32 40] A number of research groups have demonstrated flexible memories, thin film transistors (TFTs) and integrated circuits (ICs) as key technology for data processing, information storage, and communication.[41 49] Since Kim et al.[50] reported functional flexible resistive random access memory (RRAM) various chalcogenidebased phase change memories (PCMs)[51 54] as well as RRAMs using inorganic (e.g. WO3, Al2O3, HfO2, TiO2) carbon (graphene, carbon nanotubes (CNTs)[58 64] and organic materials[65 68] have been fabricated on polymer films. In addition, an ultrathin TFT and Si based large scale integration (LSI) were demonstrated for high density flexible electronics.[8,69,70] Beyond the front end device level, flexible packaging has been developed to interconnect core and peripheral modules to realize fully operational system on plastic (SoP)[71 75] Neuromorphic computing systems (brain inspired model of parallel neuron network) are considered as a promising technology for AI applications, overcoming the limitation of von Neumann architecture (serial and iterative processing) for intelligent data analysis and low power consumption.[76 81] With the rapid advancement in the electronics (e.g. memristor, PCM, and TFT) on plastics or any type of surface,[82 90] emulation of biological synapses (adaptive synaptic weight,[91 94] and spike timing dependent plasticity (STDP)[95 99] of neurons) is being demonstrated on flexible substrate, which realizes an era of merged electronics toward cognitive IoT, physiological sensor, wearable computer, and autonomous driving system.[92,100] Here, we present recent progress in the field of electronics for flexible and neuromorphic applications that can be classified into four main categories: i) various devices (e.g. resistive memory, PCM, TFT, and IC) on plastic for computing, ii) flexible electronic systems using large scale interconnection and packaging, iii) electronics for neuromorphic engineering, and iv) promising research areas of flexible synaptic applications. In addition, we have organized the main features of the studies in each section as a table to clearly compare their performance and challenges. The new electronic concept of a flexible and Novel Electronics for Flexible and Neuromorphic Computing", "author_names": [ "Han Eol Lee", "Jung Hwan Park", "Tae Jin Kim", "Doyoung Im", "Jung Ho Shin", "Do Hyun Kim", "Baker Mohammad", "Il-Suk Kang", "Keon Jae Lee" ], "corpus_id": 105193957, "doc_id": "105193957", "n_citations": 61, "n_key_citations": 0, "score": 0, "title": "Novel Electronics for Flexible and Neuromorphic Computing", "venue": "", "year": 2018 }, { "abstract": "A memristive nonvolatile logic in memory circuit can provide a novel energy efficient computing architecture for battery powered flexible electronics. However, the cell to cell interference existing in the memristor crossbar array impedes both the reading process and parallel computing. Here, it is demonstrated that integration of an amorphous In Zn Sn O (a IZTO) semiconductor based selector (1S) device and a poly(1,3,5 trivinyl 1,3,5 trimethyl cyclotrisiloxane) (pV3D3) based memristor (1M) on a flexible substrate can overcome these problems. The developed a IZTO based selector device, having a Pd/a IZTO/Pd structure, exhibits nonlinear current voltage (I V) characteristics with outstanding stability against electrical and mechanical stresses. Its underlying conduction mechanism is systematically determined via the temperature dependent I V characteristics. The flexible one selector one memristor (1S 1M) array exhibits reliable electrical characteristics and significant leakage current suppression. Furthermore, single instruction multiple data (SIMD) the foundation of parallel computing, is successfully implemented by performing NOT and NOR gates over multiple rows within the 1S 1M array. The results presented here will pave the way for development of a flexible nonvolatile logic in memory circuit for energy efficient flexible electronics.", "author_names": [ "Byung Chul Jang", "Yunyong Nam", "Beom Jun Koo", "Junhwan Choi", "Sung Gap Im", "Sang-Hee Ko Park", "Sung-Yool Choi" ], "corpus_id": 104074064, "doc_id": "104074064", "n_citations": 34, "n_key_citations": 0, "score": 0, "title": "Memristive Logic in Memory Integrated Circuits for Energy Efficient Flexible Electronics", "venue": "", "year": 2018 }, { "abstract": "Traditional textile materials can be transformed into functional electronic components upon being dyed or coated with films of intrinsically conducting polymers, such as poly(aniline) poly(pyrrole) and poly(3,4 ethylenedioxythiophene) A variety of textile electronic devices are built from the conductive fibers and fabrics thus obtained, including: physiochemical sensors, thermoelectric fibers/fabrics, heated garments, artificial muscles and textile supercapacitors. In all these cases, electrical performance and device ruggedness is determined by the morphology of the conducting polymer active layer on the fiber or fabric substrate. Tremendous variation in active layer morphology can be observed with different coating or dyeing conditions. Here, we summarize various methods used to create fiber and fabric based devices and highlight the influence of the coating method on active layer morphology and device stability.", "author_names": [ "Linden K Allison", "Steven Hoxie", "Trisha L Andrew" ], "corpus_id": 3706717, "doc_id": "3706717", "n_citations": 71, "n_key_citations": 2, "score": 0, "title": "Towards seamlessly integrated textile electronics: methods to coat fabrics and fibers with conducting polymers for electronic applications.", "venue": "Chemical communications", "year": 2017 }, { "abstract": "Soft features in electronic devices have provided an opportunity of gleaning a wide spectrum of intimate biosignals. Lack of data processing tools in a soft form, however, proclaims the need of bulky wires or low performance near field communication externally linked to a \"rigid\" processor board, thus tarnishing the true meaning of \"soft\" electronics. Furthermore, although of rising interest in stretchable hybrid electronics, lack of consideration in multilayer, miniaturized design and system level data computing limits their practical use. The results presented here form the basis of fully printable, system level soft electronics for practical data processing and computing with advanced capabilities of universal circuit design and multilayer device integration into a single platform. Single droplet printing based integration of rigid islands and core shell vertical interconnect access (via) into a common soft matrix with a symmetric arrangement leads to a double side universal soft electronic platform that features site selective, simultaneous double side strain isolation, and vertical interconnection, respectively. Systematic studies of island morphology engineering, surface strain mapping, and electrical analysis of the platform propose optimized designs. Commensurate with the universal layout, a complete example of double side integrated, stretchable 1 MHz binary decoders comprised of 36 logic gates interacting with 9 vias is demonstrated by printing based, double side electronic functionalization.", "author_names": [ "Junghwan Byun", "Eunho Oh", "Byeongmoon Lee", "Sangwoo Kim", "Seunghwan Lee", "Yongtaek Hong" ], "corpus_id": 102629099, "doc_id": "102629099", "n_citations": 23, "n_key_citations": 1, "score": 0, "title": "A Single Droplet Printed Double Side Universal Soft Electronic Platform for Highly Integrated Stretchable Hybrid Electronics", "venue": "", "year": 2017 }, { "abstract": "Organic and printed electronics integration has the potential to revolutionize many technologies, including biomedical diagnostics. This work demonstrates the successful integration of multiple printed electronic functionalities into a single device capable of the measurement of hydrogen peroxide and total cholesterol. The single use device employed printed electrochemical sensors for hydrogen peroxide electroreduction integrated with printed electrochromic display and battery. The system was driven by a conventional electronic circuit designed to illustrate the complete integration of silicon integrated circuits via pick and place or using organic electronic circuits. The device was capable of measuring 8 mL samples of both hydrogen peroxide (0 5 mM, 2.72 x 10 6 A*mM 1) and total cholesterol in serum from 0 to 9 mM (1.34 x 10 8 A*mM 1, r2 0.99, RSD 10% n 3) and the result was output on a semiquantitative linear bar display. The device could operate for 10 min via a printed battery, and display the result for many hours or days. A mobile phone \"app\" was also capable of reading the test result and transmitting this to a remote health care provider. Such a technology could allow improved management of conditions such as hypercholesterolemia.", "author_names": [ "Termeh Ahmadraji", "Laura Gonzalez-Macia", "Tapio Ritvonen", "Andreas Willert", "Satu Ylimaula", "Dave Donaghy", "Saara Tuurala", "Mika Suhonen", "Dave Smart", "Aoife Morrin", "Vitaly Efremov", "Reinhard R Baumann", "Munira Raja", "Antti Kemppainen", "Anthony J Killard" ], "corpus_id": 206508520, "doc_id": "206508520", "n_citations": 19, "n_key_citations": 1, "score": 0, "title": "Biomedical Diagnostics Enabled by Integrated Organic and Printed Electronics.", "venue": "Analytical chemistry", "year": 2017 } ]
supercritical Co2 clean semiconductor narrow pattern
[ { "abstract": "Supercritical fluids (SCFs) process can be considered as an emerging \"clean\" technology for the production of small size particles (e.g. micron size) Microsphere is a material in micron scale which has been widely used as adsorbent, catalyst support, and drug delivery system. For advanced application, those materials are formulated in the form of porous microspheres. There are several methods that can be used using SCFs. One of them is Solution Enhanced Dispersion by Supercritical Fluids (SEDS) This method is considered to be suitable in obtaining the porous microsphere polystyrene. In this study, polystyrene was first dissolved into toluene (polystyrene solution) at different concentrations (i.e. 3, 5, 7, 9, 11, 13, 15 wt% and then blown/sprayed together with supercritical carbon dioxide (CO2) through co axial nozzle with two differents annulus diameter (i.e. 3.6 mm and 4.6 mm) Co axial nozzle consists of two concentric pipes, inner pipe and annulus. Inner pipe for polystyrene solution flow and annulus for supercritical carbon dioxide flow. The expansion of these two of fluid was done both in atmospheric condition and in pressurized precipitator (40 bar) The resulted microsphere was analyzed by using SEM (Scanning Electron Microscope) to determine morphology and average diameter of the microsphere. The SEM analysis results showe that the smaller the initial concentration of solution used, the resulted microspheres tend to be smaller and less fibrils formed. Additionally, in the pressurized precipitator, the formed microspheres size was smaller and size distribution more narrow than that of atmospheric condition. Moreover, the use of smaller annulus diameter in co axial nozzle produced smaller microsphere size and the size distribution was more uniform.", "author_names": [ "Achmad Chafidz", "Umi Rofiqah", "", "Mujtahid Kaavessina", "Thonthowy Jauhary" ], "corpus_id": 195555786, "doc_id": "195555786", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Production of Microsphere Polystyrene Using Solution Enhanced Dispersion by CO2 Supercritical Fluids (SEDS)", "venue": "Key Engineering Materials", "year": 2019 }, { "abstract": "Microcellular foams are well known polymeric materials since they present excellent properties: high impact strength, high toughness, high stiffness to weight ratio, high fatigue life as well as low dielectric constant and low thermal conductivity. Environment friendly techniques are being proposed to prepare polymeric foams. In particular, supercritical CO2 (scCO2) has received great attention instead of traditional blowing agents (chlorofluorocarbon hydrochlorofluorocarbons or hydrocarbons) due to its low cost and mild impact on the environment. In the foaming process proposed in this work, mild working conditions (90 bar and 30 degC) were required thanks to the presence of CO2 and p cymene, which benefits the nucleation and cell growth. The influence of inorganic particles (silica and montmorillonite) on the cell morphology was studied experimentally and theoretically in order to promote the simultaneous formation of the embryos, thereby reducing the average cell size and narrowing the cell size distribution. A great enhancement of the polystyrene foam homogeneity was observed, independent of the nucleating agent employed and under low temperature conditions.Graphical Abstract", "author_names": [ "Cristina Gutierrez", "M Teresa Garcia", "R Mencia", "Ignacio Garrido", "J F Rodriguez" ], "corpus_id": 137708259, "doc_id": "137708259", "n_citations": 11, "n_key_citations": 1, "score": 0, "title": "Clean preparation of tailored microcellular foams of polystyrene using nucleating agents and supercritical CO2", "venue": "Journal of Materials Science", "year": 2016 }, { "abstract": "Facile synthesis and application of nano sized semiconductor metal oxides for optoelectronic devices have always affected fabrication challenges since it involves multi step synthesis processes. In this regard, semiconductor oxides derived directly from metal organic frameworks (MOFs) routes have gained a great deal of scientific interest owing to their high specific surface area, regular and tunable pore structures. Exploring the application potential of these MOF derived semiconductor oxides systems for clean energy conversion and storage devices is currently a hot topic of research. In this study, titanium based MIL 125(Ti) MOFs were used as a precursor to synthesize cobalt doped TiO2 based dye sensitized solar cells (DSSCs) for the first time. The thermal decomposition of the MOF precursor under an air atmosphere at 400 degC resulted in mesoporous anatase type TiO2 nanoparticles (NPs) of uniform morphology, large surface area with narrow pore distribution. The Co2+ doping in TiO2 leads to enhanced light absorption in the visible region. When used as photoanode in DSSCs, a good power conversion efficiency (PCE) of 6.86% with good photocurrent density (Jsc) of 13.96 mA cm 2 was obtained with the lowest recombination resistance and the longest electron lifetime, which is better than the performance of the pristine TiO2 based photoanode.", "author_names": [ "R Krishnapriya", "C Nizamudeen", "Bhagirath Saini", "Mohammad Sayem Mozumder", "Abdel Hamid I Mourad" ], "corpus_id": 236988778, "doc_id": "236988778", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "MOF derived Co2+ doped TiO2 nanoparticles as photoanodes for dye sensitized solar cells", "venue": "Scientific reports", "year": 2021 }, { "abstract": "Introduction As semiconductor devices continue to shrink and become faster, new materials and processes will be required to enable the continuation of this progress. Supercritical CO2 (SCCO2) based technology has been proposed for various steps in device fabrication, such as cleaning and deposition. SCCO2 diffuses rapidly, has low viscosity, near zero surface tension like a gas, and thus, can penetrate easily into deep trenches and vias. It also enables cleaning without pattern collapse or stiction. SCCO2 has the solvating properties of a liquid and thus can dissolve chemicals, such as alcohols and fluorinated hydrocarbons, forming a homogenous supercritical fluid solution. SCCO2 based processing has been investigated because of its potential to strip photoresist residues (thanks to its compatibility with low k materials) [1] and because it can restore the k values of low k materials for Cu/low k integration in the back end of the line (BEOL) [2] The application of SCCO2 to ultra low k material processing is a promising future technique. In this paper, we first review various applications of SCCO2 in BEOL and then we demonstrate several applications of supercritical CO2 addressed to the front end of the line (FEOL) in semiconductor and nanoelectoronic device fabrication.", "author_names": [ "Koichiro Saga", "Takeshi Hattori" ], "corpus_id": 138476202, "doc_id": "138476202", "n_citations": 18, "n_key_citations": 0, "score": 1, "title": "Wafer Cleaning Using Supercritical CO2 in Semiconductor and Nanoelectronic Device Fabrication", "venue": "", "year": 2007 }, { "abstract": "Introduction The design rule of the recent memory device is rapidly shrinking. In particular, preventing the pattern collapse in drying process is the most critical task for controlling defects because high aspect ratio nano scale structures can be large enough to cause pattern collapse. The drying technology using supercritical CO2 fluid has been investigated in order to apply it to a semiconductor manufacturing process for years because of its excellent properties such as zero surface tension, inert gas and easy to handle it [1, 2, 3] However, there are many technical problems to apply supercritical CO2 drying process with controlling nanoscale defects to a 300mm wafer manufacturing. In our study, a large number of particles were detected on a 300mm wafer by supercritical CO2 drying processing. The process control of particles and defects on nano scale is necessary to achieve high yield of the memory device manufacturing. The authors aimed at supercritical CO2 drying process enabling particle control of less than 40nm size in order to apply it to 300mm wafer memory manufacturing.", "author_names": [ "Hidekazu Hayashi", "Hisashi Ookuchi", "Hiroshi Tomita", "Yoshinori Ono", "Tadashi Nakamori", "Hiroshi Sugawara" ], "corpus_id": 215541256, "doc_id": "215541256", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Control Contaminations of Supercritical CO2 Drying Process for Nano scale Memory Manufacturing", "venue": "", "year": 2013 }, { "abstract": "Abstract We present a \"one pot\" supercritical approach for creating organized metal nanoparticle arrays. For this an improved method of deposition of micelles formed by semifluorinated poly(methyl methacrylate) block poly(perfluoroalkyl methacrylate) diblock copolymers in supercritical CO2 solution is applied. The presented approach provides metal clusters with a controlled inter particle spacing and relatively narrow size distributions in a single step \"one pot\" process during which the micelle formation proceeds simultaneously with organometallic Pt precursor dissolution and reduction inside the high pressure vessel containing a proper substrate. Subsequent decompression of the vessel results in patterned clusters of reduced metallic nanoparticles on the substrate. Presented approach of producing such raspberry like Pt clusters is relatively simple as compared to other time consuming multi step processes, and the resulting structures seem to be promising for electro catalytical applications.", "author_names": [ "Dmitry O Kolomytkin", "Igor V Elmanovich", "Sergey S Abramchuk", "Larisa A Tsarkova", "Doris Pospiech", "Martin Moller", "Marat O Gallyamov", "Alexei R Khokhlov" ], "corpus_id": 93931239, "doc_id": "93931239", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Raspberry like Pt clusters with controlled spacing produced by deposition of loaded block copolymer micelles from supercritical CO2", "venue": "", "year": 2015 }, { "abstract": "Chemists and industrialists are continuously attempting to develop greener and more environmentally benign chemical processes to extract essential oils and bioactive metabolites of high purity, finding various applications in cosmetics, detergents, nutraceuticals and pharmaceuticals. An increase preference for natural products over synthetic ones has made supercritical fluid technology a primary alternative for the generation of high value bioactive ingredients. This effective technique requires only moderate temperatures, eliminates clean up steps, and avoids the use of harmful organic solvents. In this context, our study was focused on the chemical analysis of Calamintha nepeta subsp. nepeta aromatic extracts obtained with supercritical Carbon Dioxide (CO2 The effect of different operating conditions on the capacity of the lipophilic solvent to extract the targeted volatile components was also studied. The process was carried out at fairly low constant temperature of 40 degC, and with varying the pressure from 90 to 300 bar. The chemical composition of the extracts was analyzed by gas chromatography mass spectroscopy (GC MS) The results showed that the composition pattern, the concentrations of individual components and the quality of the extractable analytes, are affected by pressure increase. The extraction yields varied from 0.73 to 1.21 (wt. at 90 bar and 300 bar, respectively.", "author_names": [ "Haifa Debbabi", "Ridha El Mokni", "Siwar Majdoub", "A G Aliev", "Saoussen Hammami" ], "corpus_id": 218490379, "doc_id": "218490379", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The Effect of Pressure on the Characteristics of Supercritical Carbon Dioxide Extracts from Calamintha nepeta subsp. nepeta.", "venue": "Biomedical chromatography BMC", "year": 2020 }, { "abstract": "Abstract Supercritical carbon dioxide (SCCO2) is an established precision cleaning technique with applications in many different industries. The gas like viscosity and the liquid like density of CO2 are the key characteristics that allow the process to be tuned to the application. In addition, the very low surface tension of SCCO2 ensures high wettability and makes it very attractive for precision cleaning applications. The cleaning process is operated at near ambient temperatures. Applications range from cleaning and drying of micro and nanostructures such as carbon nanotubes; terminal sterilization of microbial organisms and food pasteurization; cleaning of metal surfaces, glass, optical elements, silicon wafers, and polymers; cleaning of soiled banknotes and other secure documents; precision cleaning and drying of narrow tubes and parts with complex geometries and tight spaces; sterilization of medical equipment; pesticide mitigation in museum collections; and decontamination of hazardous materials.", "author_names": [ "Rajiv Kohli" ], "corpus_id": 134672079, "doc_id": "134672079", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Applications of Supercritical Carbon Dioxide for Removal of Surface Contaminants", "venue": "", "year": 2019 }, { "abstract": "Abstract Photoreduction of CO2 into valuable fuels is a clean and sustainable way to mitigate the energy crisis and environmental problems. Factors limiting the efficiency of CO2 photoreduction include narrow band light absorption, poor charge carrier separation and transport, and sluggish activation/reaction of CO2 on the surface of photocatalyst. In recent years, defect engineering of photocatalysts emerges as an effective method to improve their efficiency in the photocatalytic conversion of CO2 into useful fuels. This review is focused on discussing how structural defects can be used to modulate the electronic structure of the photocatalysts and activate the inert CO2 molecules. Special emphasis is placed on the important impact of defects on the charge carrier dynamics of the photocatalysts. Our discussions cover a variety of defective semiconductors, including metal oxides, metal sulfides, and two dimensional materials. In addition, the challenges and prospects of defect engineering in photoreduction of CO2 are also analyzed. This review aims to provide useful information about the fundamental principles of photoreduction of CO2 and guidance on the design and preparation of defective photocatalysts.", "author_names": [ "Yiqiang He", "Qiong Lei", "Chunguang Li", "Shouhua Feng" ], "corpus_id": 235554615, "doc_id": "235554615", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Defect engineering of photocatalysts for solar driven conversion of CO2 into valuable fuels", "venue": "", "year": 2021 }, { "abstract": "The invention discloses a supercritical CO2 cleaning device for semiconductor refrigeration; wherein, the device comprises a supercritical cleaning chamber which is used for cleaning silicon wafers and consists of a high pressure reaction chamber 4 and a temperature control chamber 5; wherein, the high pressure reaction chamber 4, used for storing silicon wafers and providing CO2 gasification cleaning, is arranged above the temperature control chamber 5 the temperature control chamber 5 is connected with the high pressure reaction chamber 4 by an evaporator coil, thus realizing the refrigerating and heating of the high pressure reaction chamber 4; the supercritical CO2 cleaning device also comprises a separation decompression chamber 6; the separation decompression chamber 6 is connected with the high pressure reaction chamber 4 by pipelines, is used for separating alcohols from CO2 after decompression and circularly uses the CO2; the supercritical cleaning chamber is fixedly connected with the separation decompression chamber 6 by a bearing platform 2. The supercritical CO2 cleaning device solves the problem of cleaning semiconductor in micro electrons technic, reduces the damage on the substrate, and achieves the object of saving energy by circularly utilizing the CO2.", "author_names": [ "" ], "corpus_id": 139754927, "doc_id": "139754927", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Supercritical CO2 cleaning device for semiconductor refrigeration", "venue": "", "year": 2007 } ]
Efficient Hybrid Solar Cells Based on Meso-Superstructured Organometal Halide Perovskites
[ { "abstract": "Perovskite Photovoltaics For many types of low cost solar cells, including those using dye sensitized titania, performance is limited by low open circuit voltages. Lee et al. (p. 643, published online 4 October; see the Perspective by Norris and Aydil) have developed a solid state cell in which structured films of titania or alumina nanoparticles are solution coated with a lead halide perovskite layer that acts as the absorber and n type photoactive layer. These particles are coated with a spirobifluorene organic hole conductor in a solar cell with transparent oxide and metal contacts. For the alumina particles, power conversion efficiencies of up to 10.9% were obtained. Mesostructured alumina acts as an insulating scaffold for the assembly of very thin films of n and p type semiconductors. The energy costs associated with separating tightly bound excitons (photoinduced electron hole pairs) and extracting free charges from highly disordered low mobility networks represent fundamental losses for many low cost photovoltaic technologies. We report a low cost, solution processable solar cell, based on a highly crystalline perovskite absorber with intense visible to near infrared absorptivity, that has a power conversion efficiency of 10.9% in a single junction device under simulated full sunlight. This \"meso superstructured solar cell\" exhibits exceptionally few fundamental energy losses; it can generate open circuit photovoltages of more than 1.1 volts, despite the relatively narrow absorber band gap of 1.55 electron volts. The functionality arises from the use of mesoporous alumina as an inert scaffold that structures the absorber and forces electrons to reside in and be transported through the perovskite.", "author_names": [ "Michael M Lee", "Joel Teuscher", "Tsutomu Miyasaka", "Takurou N Murakami", "Henry J Snaith" ], "corpus_id": 37971858, "doc_id": "37971858", "n_citations": 7384, "n_key_citations": 55, "score": 1, "title": "Efficient Hybrid Solar Cells Based on Meso Superstructured Organometal Halide Perovskites", "venue": "Science", "year": 2012 }, { "abstract": "Recently, inorganic and hybrid light absorbers such as quantum dots and organometal halide perovskites have been studied and applied in fabricating thin film photovoltaic devices because of their low cost and potential for high efficiency. Further boosting the performance of solution processed thin film solar cells without detrimentally increasing the complexity of the device architecture is critically important for commercialization. Here, we demonstrate photocurrent and efficiency enhancement in meso superstructured organometal halide perovskite solar cells incorporating core shell Au@SiO2 nanoparticles (NPs) delivering a device efficiency of up to 11.4% We attribute the origin of enhanced photocurrent to a previously unobserved and unexpected mechanism of reduced exciton binding energy with the incorporation of the metal nanoparticles, rather than enhanced light absorption. Our findings represent a new aspect and lever for the application of metal nanoparticles in photovoltaics and could lead to facile tuning of exciton binding energies in perovskite semiconductors.", "author_names": [ "Wei Zhang", "Michael Saliba", "Samuel D Stranks", "Yao Sun", "Xian Shi", "Ulrich B Wiesner", "Henry J Snaith" ], "corpus_id": 37918428, "doc_id": "37918428", "n_citations": 435, "n_key_citations": 3, "score": 0, "title": "Enhancement of perovskite based solar cells employing core shell metal nanoparticles.", "venue": "Nano letters", "year": 2013 }, { "abstract": "To date, numerous approaches have been developed for fabricating high quality organometal halide perovskite thin films, however, perovskite films obtained by such methods reveal a brown or dark brown color, which might restrain their light absorption ability. Here we report a route to synthesize dark blue mirror like perovskite dense films via a two step spin coating process assisted by treatment of nonpolar solvent scouring. Photovoltaic cells based on such dark blue films demonstrate a high short circuit current density (Jsc) of ~23 mA cm 2 and a power conversion efficiency (PCE) of 16.1% Our method would provide a new candidate method for the fabrication of perovskite solar cells with high performance.", "author_names": [ "Jianhang Qiu", "Wang Gaoxiang", "Wenjing Xu", "Jin Qun", "Lusheng Liu", "Bing-Ping Yang", "Tai Kaiping", "Anyuan Cao", "Xin Jiang" ], "corpus_id": 56339157, "doc_id": "56339157", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Dark blue mirror like perovskite dense films for efficient organic inorganic hybrid solar cells", "venue": "", "year": 2016 }, { "abstract": "For efficient hybrid solar cells based on organometal halide perovskites, the real origin of the I V hysteresis became a big issue and has been discussed widely. In this study, simulated I V curves.", "author_names": [ "Ludmila Cojocaru", "Satoshi Uchida", "P V V Jayaweera", "Shoji Kaneko", "Jotaro Nakazaki", "Takaya Kubo", "Hiroshi Segawa" ], "corpus_id": 98707369, "doc_id": "98707369", "n_citations": 78, "n_key_citations": 0, "score": 0, "title": "Origin of the Hysteresis in I V Curves for Planar Structure Perovskite Solar Cells Rationalized with a Surface Boundary induced Capacitance Model", "venue": "", "year": 2015 }, { "abstract": "Organometal halide perovskites are promising solar cell materials for next generation photovoltaic applications. The long carrier lifetime and diffusion length of these materials make them very attractive for use in light absorbers and carrier transporters. While these aspects of organometal halide perovskites have attracted the most attention, the consequences of the Rashba effect, driven by strong spin orbit coupling, on the photovoltaic properties of these materials are largely unexplored. In this work, taking the electronic structure of methylammonium lead iodide as an example, we propose an intrinsic mechanism for enhanced carrier lifetime in 3D Rashba materials. Based on first principles calculations and a Rashba spin orbit model, we demonstrate that the recombination rate is reduced due to the spin forbidden transition. These results are important for understanding the fundamental physics of organometal halide perovskites and for optimizing and designing the materials with better performance. The proposed mechanism including spin degrees of freedom offers a new paradigm of using 3D Rashba materials for photovoltaic applications. The organometal halide perovskites (OMHPs) have attracted significant attention due to the rapid increase in their photovoltaic power conversion efficiency. In the past 2 years, the reported efficiency of OMHP based solar cells has almost doubled from 9.7%1 to over 20%,2 4 making OHMPs very promising for low cost and high efficiency photovoltaics. Methylammonium lead iodide, CH3NH3PbI3 (MAPbI3) and other closely related hybrid perovskites such as Cl doped and Br doped MAPbI3 (MAPbI3 xClx and MAPbI3 xBrx) (NH2)2CHPbI3 (formamidinium lead iodide, FAPbI3) and Sn doped MAPbI3 (MAPbxSn1 xI3) all display band gaps (1.1 to 2.1 eV) in the visible light region, favorable for photovoltaic applications.5 13 The class of materials also possesses strong light absorption, fast charge generation and high carrier mobility.14,15 In particular, exceptionally long carrier lifetime and diffusion length have been observed in MAPbI3 and MAPbI3 xClx, making them better solar cell candidates than other semiconductors with similar band gaps and absorption coefficients.16 18 Intense research has been directed toward understanding and further enhancing the long carrier lifetime and diffusion length in OMHPs. Previous studies reported a relatively low defect 2 concentration in MAPbI3, which reduces the scattering centers for nonradiative charge carrier recombination. Recently, it has been suggested that the spatial carrier segregation caused by disorder induced localization24 or domains acting as internal p n junctions25 27 may reduce the recombination rate. Though many of the OMHPs are 3D Rashba materials driven by strong spin orbit coupling (SOC) and bulk ferroelectricity,28 31 the effects of spin and orbital degrees of freedom on photovoltaic applications are largely unexplored beyond band gap engineering.29 In this work, we focus on an intrinsic mechanism for the enhancement of long carrier lifetime due to the Rashba splitting. Using first principles calculations and effective models, we find that the Rashba splitting arising from SOC under inversion symmetry breaking can result in spin allowed and spin forbidden recombination channels. The spin forbidden recombination path has a significantly slower transition rate due to the mismatch of spin and momentum. The spin allowed recombination path, though kinetically favorable, can be suppressed under appropriate spin texture due to the low population of free carriers. Taking the electronic structures of MAPbI3 under various distortions as examples, we show that the proposed mechanism is possible under room temperature, and is potentially responsible for the long carrier lifetime in OMHPs. This spindependent recombination mechanism highlights the possibility of using 3D Rashba materials for efficient photovoltaic applications. Fig. 1 illustrates the mechanism for enhancing the carrier lifetime in a generic 3D Rashba material. The strong spin orbit coupling effect from heavy elements (e.g. Pb, Sn, I and Br) and the polar distortion (e.g. aligned molecular dipoles in OMHPs) give rise to the Rashba effect, which lifts the two fold degeneracy of bands near the band gap. Near the band gap, the spin degeneracies of the conduction and valence bands are lifted, giving rise to \"inner\" and \"outer\" bands with opposite spin textures, characterizing spin rotation direction as \"clockwise\" (kh 1) and \"counterclockwise\" (kh +1) (Fig. 1) The photo excitation process creates free electrons and holes, which can quickly relax to band extrema in the presence of inelastic phonon scattering. When the spin textures of conduction band minimum (CBM) and valence band maximum (VBM) are opposite, the radiative recombination of Ckh= 1 Vkh=+1 is a spin forbidden transition due", "author_names": [ "Fan Zheng", "Liang Z Tan", "Shi Liu", "Andrew M Rappe" ], "corpus_id": 119239379, "doc_id": "119239379", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Rashba Spin Orbit Coupling Enhanced Carrier Lifetime in Organometal Halide Perovskites", "venue": "", "year": 2015 }, { "abstract": "Hybrid solar cells based on organometal halide perovskite absorbers have recently emerged as promising class for cost and energy efficient photovoltaics. So far, unraveling the morphology of the different materials within the nanostructured absorber layer has not been accomplished. Here, we present the first visualization of the mesoporous absorber layer in a perovskite solar cell from analytical transmission electron microscopy studies. Material contrast is achieved by electron spectroscopic imaging. We found that infiltration of the hole transport material into the scaffold is low and inhomogeneous. Furthermore, our data suggest that the device performance is strongly affected by the morphology of the TiO2 scaffold with a fine grained structure being disadvantageous.", "author_names": [ "Diana Nanova", "Anne Katrin Kast", "Martin Pfannmoller", "Christian Muller", "Lisa Veith", "Irene Wacker", "Michaela Agari", "Wilfried Hermes", "Peter Erk", "Wolfgang Kowalsky", "Rasmus R Schroder", "Robert Lovrincic" ], "corpus_id": 5163852, "doc_id": "5163852", "n_citations": 53, "n_key_citations": 0, "score": 0, "title": "Unraveling the nanoscale morphologies of mesoporous perovskite solar cells and their correlation to device performance.", "venue": "Nano letters", "year": 2014 }, { "abstract": "Hybrid perovskites have recently seen an unprecedented improvement in the power conversion efficiency in photovoltaics devices, and therefore are very promising materials for developing efficient and low cost single junction solar cells [1 3] However, a critical issue is the limited understanding of the correlation between the degree of crystallinity and the emergent perovskite/hole (or electron) transport layer on device performance as well as photo stability. Los Alamos National laboratory (LANL) developed an efficient growth procedure for 3D halide perovskites in inverted perovskite cell architecture using PEDOT PSS as a p type hole transporting material (HTM) [4] The initial collaboration between FOTON/ISCR and LANL led to the observation of a reversible self healing mechanism under light soaking [5] and showed that the aging of the precursor solution plays a role in the nucleation of the perovskite crystallites [6] In this study, we show that growth of methylammonium lead perovskites (MAPbI3) on nickel oxide (NiO) HTM, results in the formation of ordered and crystalline thin films with enhanced crystallinity, leading to characteristic XRD Bragg peak width reminiscent of exclusively observed in the tetragonal phase in single crystals. Photo physical and interface sensitive measurements reveal a reduced trap density at the MAPbI3 perovskite/NiO interface in comparison with perovskites grown on PEDOT: PSS. Photovoltaic cells exhibit a high open circuit voltage (1.12 V) indicating a nearideal energy band alignment. Moreover, we observe photo stability of photovoltaic devices up to 10 Suns, which is a direct result of the enhanced crystallinity of perovskite thin films on NiO. These results elucidate the critical role of the quality of the perovskite/HTL interface in rendering highperformance and photo stable optoelectronic devices [7] [1] Lee, M. M. Teuscher, J. Miyasaka, T. Murakami, T. N. Snaith, H. J. \"Efficient Hybrid Solar Cells Based on Meso Superstructured Organometal Halide Perovskites\" Science 338, 643 (2012) [2] Burschka, J. et al. \"Sequential deposition as a route to high performance perovskitesensitized solar cells\" Nature 499, 316 319 (2013) [3] Jeon, N. J. et al. \"Solvent engineering for high performance inorganic organic hybrid perovskite solar cells\" Nat. Mater. 13, 897 903 (2014) [4] Nie, W. et al, \"High efficiency solution processed perovskite solar cells with millimeterscale grains\" Science 347, 522 (2015) [5] Nie, W. et al, \"Light activated photocurrent degradation and self healing in perovskite solar cells\" Nat. Comm. 7, 11574 (2016) [6] Tsai, H. et al,\" Effect of Precursor Solution Aging on the Crystallinity and Photovoltaic Performance of Perovskite Solar Cells\" Adv. Ener. Mat. 7, 1602159 (2017) [7] Nie, W. et al, Adv. Mater. (In press)", "author_names": [ "Olivier Durand", "Wanyi Nie", "Hsinhan Tsai", "Reza Asadpour", "Jean-Christophe Blancon", "Fangze Liu", "Constantinos C Stoumpos", "Joseph W Strzalka", "Jared J Crochet", "Pulickel M Ajayan", "Boubacar Traore", "Mikael Kepenekian", "Claudine Katan", "Sergei Tretiak", "Mercouri G Kanatzidis", "Muhammad A Alam", "Jacky Even", "Aditya D Mohite" ], "corpus_id": 105191302, "doc_id": "105191302", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Critical role of Interface and perovskite lattice in high efficiency and photostable solar cells", "venue": "", "year": 2017 }, { "abstract": "Due to their outstanding optical properties and superior charge carrier mobilities, organometal halide perovskites have been widely investigated in photodetection and solar cell areas. In perovskites photodetection devices, their high optical absorption and excellent quantum efficiency contribute to the responsivity, even the specific detectivity. In this work, we developed a lateral phototransistor based on mesoscopic graphene/perovskite heterojunctions. Graphene nanowall shows a porous structure, and the spaces between graphene nanowall are much appropriated for perovskite crystalline to mount in. Hot carriers are excited in perovskite, which is followed by the holes' transfer to the graphene layer through the interfacial efficiently. Therefore, graphene plays the role of holes' collecting material and carriers' transporting channel. This charge transfer process is also verified by the luminescence spectra. We used the hybrid film to build phototransistor, which performed a high responsivity and specific detectivity of 2.0 x 103 A/W and 7.2 x 1010 Jones, respectively. To understand the photoconductive mechanism, the perovskite's passivation and the graphene photogating effect are proposed to contribute to the device's performance. This study provides new routes for the application of perovskite film in photodetection.", "author_names": [ "Dahua Zhou", "Leyong Yu", "Peng-Li Zhu", "Hongquan Zhao", "Shuanglong Feng", "Jun Shen" ], "corpus_id": 232383548, "doc_id": "232383548", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Lateral Structured Phototransistor Based on Mesoscopic Graphene/Perovskite Heterojunctions", "venue": "Nanomaterials", "year": 2021 }, { "abstract": "A sensitized solar cell introduced by O'Regan and Gratzel in 1991 was one of the milestones in third generation hybrid solar cells because of the novelty of its architecture, ease of its fabrication, cost effectiveness and good efficiency. Despite persistent efforts made by various groups around the world for over 20 years, the efficiency of DSSCs had not crossed 13% Very recently however, a major path breaking advance has been realized in the domain of solid state sensitized solar cells with the introduction of organometal halide perovskites as efficient alternatives to liquid electrolyte based DSSCs. These new systems have already shown efficiency values of about 15 16% and hold great promise for even higher efficiency (20% at lower cost. Interestingly, the optoelectronic properties of organometal halide perovskites can be tuned by varying the organic cation sizes, metal ions, or the halide anions. Several research groups have shown that complete replacement of I with other halide ions such as Br or Cl leads to increase in the energy gap and therefore lower photocurrents and efficiency. However the presence of mixed halides in the perovskite structure such as CH3NH3PbI2Cl can lead to higher photovoltaic performance because of the increase in the carrier diffusion length (B1 mm) without an appreciable increase in the band gap. Chung et al. showed that doping inorganic perovskite CsSnI3 with 5% fluorine could dramatically improve the photocurrent density by nearly 40% However, to the best of our knowledge, there are no reports of mixed halide organometal perovskite systems with I and F ions applied in solar cells. Importantly, Mosconi et al. have shown that the mixed halide perovskite system consists of two different structures whose stability decreases from I to F along the column VIIA in the periodic table. Therefore it is difficult to stabilize I and F based mixed halide perovskite systems. Herein, we report an interesting strategy to incorporate fluoride ions in the perovskite structure via partial substitution of I by BF4 Importantly, I and BF4 both have nearly the same ionic radius, which makes the incorporation of BF4 feasible in the structure. We further show that I and BF4 based mixed halide perovskite possesses an order of magnitude higher low frequency conductivity than I based perovskite without an appreciable change in the absorption onset. In order to incorporate BF4 within the perovskite structure, the organic salt CH3NH3BF4 was prepared using methylamine and tetrafluoroboric acid solutions. The hybrid perovskite films were prepared using chemical vapor deposition of organic salt CH3NH3BF4 on preheated PbI2 films whereas the powder of hybrid perovskite was prepared using the solid state route with a mixture of organic salt and PbI2. The detailed experimental procedure is given in the ESI. The phase of the synthesized perovskite was confirmed using X ray diffraction measurements. Fig. 1(a) shows the XRD pattern of synthesized CH3NH3PbI(3 x)(BF4)x perovskite film on glass. The crystal structure of CH3NH3PbI(3 x)(BF4)x perovskite is found to be identical to the conventional CH3NH3PbI3 tetragonal perovskite structure as indicated by the appearance of peaks at 14.01, 28.31, 31.81 and 43.21 for the (110) (220) (310) and (330) planes, respectively. The presence of sharp peaks in the X ray diffraction pattern indicates the highly crystalline nature of the perovskite film. In order to confirm the presence of BF4 groups in the perovskite structure, we carried out the ATR FTIR study of the CH3NH3PbI(3 x)(BF4)x films on glass. Fig. 1(b) shows the characteristic stretching vibration peaks of BF4 at 1135 cm 967 cm 524 cm 1084 cm 952 cm 1 (for symmetric stretching) and 1053 cm 1 (B F stretching) which are otherwise absent in the CH3NH3PbI3 perovskite. a Centre of Excellence in Solar Energy, National Chemical Laboratory (CSIR NCL) Dr. Homi Bhabha Road, Pune, India b Academy of Scientific and Innovative Research (AcSIR) Network Institute of Solar Energy (CSIR NISE) New Delhi, India. E mail: satyawan.nagane@gmail.com, sb.ogale@ncl.res.in Electronic supplementary information (ESI) available: Experimental details and Fig. S1 S4. See DOI: 10.1039/c4cc04537h Received 15th June 2014, Accepted 4th July 2014", "author_names": [ "Satyawan Nagane", "Umesh Pandharinath Bansode", "Onkar S Game", "Shraddha Y Chhatre", "" ], "corpus_id": 115151000, "doc_id": "115151000", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "CH 3 NH 3 PbI 3 x BF 4 x molecular ion substituted hybrid perovskite", "venue": "", "year": 2014 }, { "abstract": "While the field of perovskite based optoelectronics has mostly been dominated by photovoltaics, light emitting diodes and transistors, semiconducting properties peculiar to perovskites make them interesting candidates for innovative and disruptive applications in light signal detection. Perovskites combine effective light absorption in the broadband range with good photo generation yield and high charge carrier mobility, which combination provides promising potential for exploiting sensitive and fast photodetectors that are targeted for image sensing, optical communication, environmental monitoring, or chemical/biological detection. Currently, organic inorganic hybrid and all inorganic halide perovskites with controlled morphologies of polycrystalline thin films, nano particles/wires/sheets, and bulk single crystals have shown key figure of merit features in terms of their responsivity, detectivity, noise equivalent power, linear dynamic range, and response speed. The sensing region has been covered from ultraviolet visible near infrared (UV Vis NIR) to gamma photons, based on two or three terminal device architectures. Diverse photoactive materials and devices with superior optoelectronic performances have stimulated attention from researchers in multidisciplinary areas. We offer a comprehensive overview of the recent progress of perovskite based photodetectors, focusing on versatile compositions, structures, and morphologies of constituent materials, and diverse device architectures toward the superior performance metrics. Combining the advantages of both organic semiconductors (facile solution processability) and inorganic semiconductors (high charge carrier mobility) perovskites are expected to replace commercial silicon for future photodetection applications. The optical and electronic properties of noble metallic nanoparticles can be exploited to enhance the performance of inorganic/organic photodetectors. We integrated a uniformly distributed layer of Au nanorods (AuNRs) into vertically structured perovskite photoconductive photodetectors and report, as a result, perovskite AuNR hybrid photodetectors that exhibit significant photocurrent enhancements. Ultimately it achieves a responsivity of ~320 A/W at a low driving voltage of 1 V. This is an improvement of 60% compared to the responsivity of pristine devices ~200 A/W) The high responsivity and low driving voltage place this device among the highest performing perovskite based thin film photoconductive photodetectors reported. We characterized the stability and linearity of the photoresponse following repeated light/dark cycles. The hybrid device also shows a fast response (with the decay time of ~95 ns) compared to pristine devices ~230 ns) The improvements in photodetection performance are attributed to plasmon enhanced optical absorption, as well as advances in charge extraction and transport. Metal halide perovskites have rapidly advanced thin film photovoltaic performance; as a result, the materials' ob served instabilities urgently require a solution. Using density functional theory (DFT) we show that a low energy of formation, exacerbated in the presence of humidity, explains the propensity of perovskites to decompose back into their precursors. We find, also using DFT, that intercalation of phenylethylammonium between perovskite layers in troduces quantitatively appreciable van der Waals interactions; and these drive an increased formation energy and should therefore improve material stability. Here we report the reduced dimensionality (quasi 2D) perovskite films that exhibit improved stability while retaining the high performance of conventional three dimensional perovskites. Continuous tuning of the dimensionality, as assessed using photophysical studies, is achieved by the choice of stoi chiometry in materials synthesis. We achieve the first certified hysteresis free solar power conversion in a planar per ovskite solar cell, obtaining a 15.3% certified PCE, and observe greatly improved performance longevity. The same protocol was applied to develop highly stable and efficient photodectors in diverse device configurations. Organometal halide perovskites exhibit large bulk crystal domain sizes, rare traps, excellent mobilities, and carriers that are free at room temperature properties that support their excellent performance in charge separating devices. In devices that rely on the forward injection of electrons and holes, such as light emitting diodes (LEDs) excellent mobilities contribute to the efficient capture of nonequilibrium charge carriers to rare nonradiative centres. Moreover, the lack of bound excitons weakens the competition of desired radiative over undesired nonradiative recombination. Here we also report a perovskite mixed material, one comprised of a series of differently quantum size tuned grains, that funnels photoexcitations to the lowest bandgap light emitter in the mixture. The materials function as charge carrier concentrators, ensuring that radiative recombination successfully outcompetes trapping and hence nonradiative recombination. We use the new material to build devices that exhibit an external quantum efficiency (EQE) of 8.8% and a radiance of 80 Wsr 1m 2. These represent the brightest and most efficient solution processed near infrared LEDs to date. Here we show that, by concentrating photoexcited states into a small subpopulation of radiative domains, one can achieve a high quantum yield even at low excitation intensities. We tailor the composition of quasi 2D perovskites to direct the energy transfer into the lowest bandgap minority phase, and to do so faster than it is lost to non radiative centres. The new material exhibits 60% photoluminescence quantum yield at excitation intensities as low as 1.8 mW/cm2, yielding a ratio of quantum yield to excitation intensity of 0.3 cm2/mW; this represents a two orders of magnitude decrease in the excitation power required to reach high efficiency compared to the best prior reports. Using this strategy, we report LEDs with EQEs of 7.4% and a high luminescence of 8400 cd/m2.", "author_names": [ "Dong Ha Kim", "Huan Mei Wang", "Ju Won Lim", "Li Na Quan", "Ilgeum Lee", "Edward H Sargent" ], "corpus_id": 139769290, "doc_id": "139769290", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Optoelectronic hybrid perovskite materials and devices (Conference Presentation)", "venue": "", "year": 2018 } ]
trends in computing
[ { "abstract": "The development of IC technology is driven by the needs to increase performance and functionality while reducing size, weight, power consumption, and manufacturing cost. As Gordon Moore predicted in his seminal paper, reducing the feature size also allows chip area to be decreased, improving production, and thereby reducing cost per function. The scaling laws showed that improved device and ultimately processor speed could be achieved through dimensional scaling. However, all trends ultimately have limits, and Moore's law is no exception. The limits to Moore's law scaling have come simultaneously from many directions. Lithographic limits have made it extremely difficult to pack more features onto a semiconductor chip, and the most advanced lithographic techniques needed to scale are becoming prohibitively expensive for most Fabs. The optical projection systems used today have very complex multielement lenses that correct for virtually all of the common aberrations and operate at the diffraction limit.", "author_names": [ "Khaled Mohamed" ], "corpus_id": 214223907, "doc_id": "214223907", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "An Introduction: New Trends in Computing", "venue": "", "year": 2020 }, { "abstract": "The presented here a collection of conference papers is a Special Volume on Recent Trends in Computing that was compiled by the editors for the Mathematical and Computational Forestry Natural Resource Sciences (MCFNS) journal. The creation of this Special Issue and the Special Section, which contains it, was requested by the organizers of the International Conference on Recent Trends in Computing (ICRTC 2017) held on Dec. 14 15, 2017, at the SRM Institute of Science and Technology (formerly SRM University) on the NCR Campus, Tamil Nadu, India. The purpose of the Special Section hosting this volume is to contain publications originated from this and other similar scientific endeavors involving research on developments of computing technology as relevant to various Computational Sciences associated with natural resources or related to their research and management. In the current issue, dedicated in its entirety to this conference, we present a set of the papers in this category, which includes 29 selected examples of research that have been reviewed externally by the conference organizers.", "author_names": [ "M Rajesh", "Varaharajan Kannan", "Chris J Cieszewski" ], "corpus_id": 149778382, "doc_id": "149778382", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Special Issue on SELECTED EXAMPLES OF RECENT TRENDS IN COMPUTING", "venue": "", "year": 2019 }, { "abstract": "A key aspect of the design of evolutionary and swarm intelligence algorithms is studying their performance. Statistical comparisons are also a crucial part which allows for reliable conclusions to be drawn. In the present paper we gather and examine the approaches taken from different perspectives to summarise the assumptions made by these statistical tests, the conclusions reached and the steps followed to perform them correctly. In this paper, we conduct a survey on the current trends of the proposals of statistical analyses for the comparison of algorithms of computational intelligence and include a description of the statistical background of these tests. We illustrate the use of the most common tests in the context of the Competition on single objective real parameter optimisation of the IEEE Congress on Evolutionary Computation (CEC) 2017 and describe the main advantages and drawbacks of the use of each kind of test and put forward some recommendations concerning their use.", "author_names": [ "Jacinto Carrasco", "Salvador Garc'ia", "Maria del Mar Rueda", "S Das", "F Herrera" ], "corpus_id": 211252376, "doc_id": "211252376", "n_citations": 70, "n_key_citations": 0, "score": 0, "title": "Recent Trends in the Use of Statistical Tests for Comparing Swarm and Evolutionary Computing Algorithms: Practical Guidelines and a Critical Review", "venue": "Swarm Evol. Comput.", "year": 2020 }, { "abstract": "Rapid and timely monitoring of traumatic inflammation is conducive to doctors' diagnosis and treatment. It has been proved that electronic nose (E nose) is an effective way to predict the bacterial classes of wound infection by smelling the odor produced by the metabolites, and it has also been found thatthe classification accuracy of E nose is very different when different feature is extracted and put into the classifier. The gas sensor array of E nose can be seen as a dynamic system whose response temporally evolves following the concentration of the odors. As the central concept in the analysis of dynamic systems, phase space is the first time to be employed by us to construct the feature matrix of wound infection data in this paper. Dynamic moments, the functions of time delay in phase space, is used as the feature of wound infection. The odors of four different classes of wound (wound uninfected, and infected withP. aeruginosa, E. coliandS. aureus) are used as the original response of Enose.Experimental results prove that the classification accuracy of test data set is 96.43% when R2 is used as the feature, which is much better than M2P, M3P (other two dynamic moments) maximum value of the steady state response and maximum value of the first order derivative (two traditional feature of E nose) Keywords Wound infection; Electronic nose; Phase space; Dynamic moments __________________________________________________**_________________________________________________", "author_names": [ "Ru-Yi Luo", "Pengfei Jia" ], "corpus_id": 212542072, "doc_id": "212542072", "n_citations": 164, "n_key_citations": 15, "score": 1, "title": "International Journal on Recent and Innovation Trends in Computing and Communication", "venue": "", "year": 2017 }, { "abstract": "The majority of the existing research regarding mobile learning in computing education has primarily focused on studying the effectiveness of, and in some cases reporting about, implemented mobile learning solutions. However, it is equally important to explore development and application perspectives on the integration of mobile learning into computing education and identify practical implications for learning and teaching practices. In this study, the authors performed a systematic review of scientific publications related to mobile learning in computing education. After identifying relevant publications, they analysed them from three main aspects: technology and development, design of mobile learning solutions and applications, and implications for learning. The authors' study reveals that mobile learning in computing education has the potential to increase several affective traits of learners. In addition, mobile learning in computing education has matured enough to be mainly concerned with the mainstreaming of the computing curriculum rather than basic research.", "author_names": [ "Ebenezer Anohah", "Solomon Sunday Oyelere", "Jarkko Suhonen" ], "corpus_id": 3646370, "doc_id": "3646370", "n_citations": 24, "n_key_citations": 2, "score": 0, "title": "Trends of Mobile Learning in Computing Education from 2006 to 2014: A Systematic Review of Research Publications", "venue": "Int. J. Mob. Blended Learn.", "year": 2017 }, { "abstract": "Brilliant ICUs are systems of varying media correspondence and PC frameworks that connection basic care specialists and medical caretakers (intensivists) to escalated mind units (ICUs) in other, remote doctor's facilities. The intensivists in the \"war room\" can impart by voice with the remote ICU staff and can get video correspondence and clinical information about the patients. Coordinate patient care is given by the specialists and medical attendants in the remote ICU who don't need to be intensivists themselves. As of late there has been an expansion in the quantity of patients requiring ICU mind without a relating increment in the supply of intensivists. Keen ICUs can be a significant asset for healing centers looked with the need to extend limit and enhance tend to a developing elderly populace. Proof from some early adopter healing centers demonstrates that it can use administration of patient care by intensivists, decrease death rates, and diminish LOS. In any case, positive results seem to rely upon the hierarchical condition into which the Smart ICU is presented. The emotional upgrades in mortality and LOS detailed by some early adopter doctor's facilities have not been coordinated in most. The constrained research accessible recommends that the best results may happen in ICUs that: Can make authoritative game plans to help the administration of patient care by intensivists utilizing Smart ICU; Have almost no intensivist staff accessible to them without Smart ICU; Have moderately high seriousness balanced mortality and LOS rates; Are situated in remote or provincial zones where protected and productive exchange of patients to local communities for cutting edge basic care presents challenges. Keen ICU interfaces a headquarters focus staffed by intensivists with patients in far off ICUs. Persistent, continuous sound, video, and electronic reports of imperative signs interface the war room to the patients' bedsides. PC oversaw choice emotionally supportive networks track every patient's status and give alarms when negative patterns are identified and when changes in treatment designs are planned. The patient information incorporate physiological status (e.g. ECG and blood oxygenation) treatment (e.g. the implantation rate for a particular prescription or the settings on a respirator) and medicinal records. Keywords Internet of Things, industrial applications, microcontroller, Smart ICU, personal computer. __________________________________________________**_________________________________________________", "author_names": [ "Anisha Chettri", "IIYear PGStudent", "Cynthia Marquardt", "Michael Breslow", "" ], "corpus_id": 221699592, "doc_id": "221699592", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "International Journal on Recent and Innovation Trends in Computing and Communication", "venue": "", "year": 2018 }, { "abstract": "In this paper, image data acquisition system has been introduced. In this task, a system of high speed image data acquisition based on ARM and FPGA is designed according to the needs of actual system in image data transmission, which can be used in data monitoring and surveillance systems. The choice of ARM is a 32 bit embedded RISC microprocessor architecture, which has a rich instruction set and programming flexibility. FPGA has a great advantage in the speed and parallel computing, suitable for real time requirements of image processing. The interface between camera module and FPGA as well as interface between FPGA and ARM is done using UART. Image from ARM is transmitted to PC using Ethernet. KeywordsCamera module, FPGA, ARM, Ethernet, UART __________________________________________________**_________________________________________________", "author_names": [ "Ms S R Lad" ], "corpus_id": 212466467, "doc_id": "212466467", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "International Journal on Recent and Innovation Trends in Computing and Communication", "venue": "", "year": 2017 }, { "abstract": "The teaching of computing is becoming an essential addition to twenty first century learning. An important part of this new addition is the teaching of computing in earlier grades, starting as early as kindergarten in some countries. Yet, there is little research that reports on computing practices in earlier grades. The purpose of this study was to paint a broad picture of the teaching of computing in primary education from teachers' perspectives through a 20 min snowball survey sent out to elementary computing groups. This study reports on the teaching of over 300 teachers who are responsible for teaching computing to nearly 60,000 primary aged students. The results principally represented teachers in the US and the UK, though smaller samples of teachers from 23 total countries are included. We report on teachers' responses by analyzing quantitative data and open ended responses to questions about their experiences in teaching computing to children. Results highlight teachers' level of preparation to teach computing, the most commonly taught programming languages, teacher successes and challenges, and observations on how learning to program has affected students.", "author_names": [ "Peter J Rich", "Samuel Frank Browning", "McKay Perkins", "Timothy Shoop", "Emily Yoshikawa", "Olga Belikov" ], "corpus_id": 64761018, "doc_id": "64761018", "n_citations": 28, "n_key_citations": 0, "score": 0, "title": "Coding in K 8: International Trends in Teaching Elementary/Primary Computing", "venue": "", "year": 2019 }, { "abstract": "Future educational technology there will be new issues, applications, teacherlearner paradigms and perspectives that will have a powerful effect in the teaching and learning process such as mobile devices, MOOCS, computer based assessment applications, teacher training methods and else that will lead to different applications and even philosophies of how educators understand or use technology. The primary issue is the applicability of different devices whether software or hardware. The second, is the accessibility which is also changing what is being taught giving ground to information, knowledge or common contents that in turn shape from the general idea of education to the daily lesson. The third is the user's training and interaction (for teachers and learners) The fact that teachers and learners can access now new materials and activities will provide educational opportunities for those who have been traditionally had positive access to education as well as those who have not. Thus technology currently will serve to build bridges to link cultures and enhance educational enriching experiences.", "author_names": [ "Jesus Garcia Laborda", "Huseyin Uzunboylu", "Steven Ross" ], "corpus_id": 9377382, "doc_id": "9377382", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Future Trends in Computing Technology in Education", "venue": "J. Univers. Comput. Sci.", "year": 2016 }, { "abstract": "Computing information intelligence is considered an extremely important asset to any organization. Techniques are set of management disciplines with the help of computing information that allow organizations to manage their technological fundamentals to create competitive business advantage. Computing information intelligence includes integrated planning, design, optimization, operation, and control of technological products, processes, and services: a better definition would be the management of the use of intelligence for human advantage. Information and computing intelligence sciences employ new technologies to solve client problems through contract research. To address the problems a lot of research efforts are still needed from both academia and industry. This special issue aims to promote research in the area of computing information intelligence in present business scenario. The article entitled \"Information Retrieval and Graph Analysis Approaches for Book Recommendation\" proposed a combination of multiple information retrieval approaches for the purpose of book recommendation. Different theoretical retrieval models, probabilistic as InL2 (divergence from randomness model) and language model, are used and we tested their interpolated combination. Graph analysis algorithms such as PageRank have been successful in Web environments. We consider the application of this algorithm in a new retrieval approach to related document network comprised of social links. A series of reranking experiments demonstrate that combining retrieval models yields significant improvements in terms of standard ranked retrieval metrics. The article entitled \"Distilling Big Data: Refining Quality Information in the Era of Yottabytes\" targets the utilization of the Fuzzy Bayesian process model to improve the quality of information in Big Data. The article entitled \"Framing a Knowledge Base for a Legal Expert System Dealing with Indeterminate Concepts\" describes the development of a negotiation decision support system (the Parenting Plan Support System or PPSS) to support parents in drafting an agreement (the parenting plan) for the exercise of parental custody of minor children after a divorce is granted. In the article entitled \"Priority Based Congestion Control Dynamic Clustering Protocol in Mobile Wireless Sensor Networks,\" in order to conserve energy and to avoid congestion during multiclass traffic a novel Priority Based Congestion Control Dynamic Clustering (PCCDC) protocol is developed. Simulation results have proven that packet drop, control overhead, and end to end delay are much lower in PCCDC which in turn significantly increases packet delivery ratio, network lifetime, and residual energy when compared with PASCC protocol. The article entitled \"Predicting Defects Using Information Intelligence Process Models in the Software Technology Project\" gave the practical applicability of using predictive models and illustrated the use of these models in a project to predict system testing defects, thus helping to reduce residual defects. The article entitled \"Scalable Clustering of High Dimensional Data Technique Using SPCM with Ant Colony Optimization Intelligence\" has been developed to cluster data using high dimensional similarity based PCM (SPCM) with ant colony optimization intelligence which is effective in clustering nonspatial data without getting knowledge about cluster number from the user. The mountain method is applied for searching approximate centers in the cluster, where the maximum density clusters are located. Though this is efficient clustering, it is checked for optimization using ant colony algorithm with swarm intelligence. Thus, the scalable clustering technique is obtained and the evaluation results are checked with synthetic datasets. In the article titled \"Multicriteria Personnel Selection by the Modified Fuzzy VIKOR Method\" personnel evaluation is an important process in human resource management; a fuzzy hybrid multicriteria decision making (MCDM) model is proposed to personnel evaluation. This model solves personnel evaluation problem in a fuzzy environment where both criteria and weights could be fuzzy sets. The triangular fuzzy numbers are used to evaluate the suitability of personnel and the approximate reasoning of linguistic values. A comparative analysis of results by fuzzy VIKOR and modified fuzzy VIKOR methods is presented. Experiments showed that the proposed modified fuzzy VIKOR method has some advantages over fuzzy VIKOR method. Firstly, from a computational complexity point of view, the presented model is effective. Secondly, compared to fuzzy VIKOR method, it has high acceptable advantage compared to fuzzy VIKOR method. The article entitled \"Traffic and Driving Simulator Based on Architecture of Interactive Motion\" proposes an architecture for an interactive motion based traffic simulation environment. The architecture has been designed to enable the simulation of the entire network; as a result, the actual driver, pedestrian, and bike rider can navigate anywhere in the system. The two traffic flow simulation models interact continuously to update system conditions based on the interactions between actual humans and the fully simulated entities. The implementation of the proposed architecture faces significant challenges ranging from multiplatform and multilanguage integration to multievent communication and coordination. The article entitled \"Proactive Alleviation Procedure to Handle Black Hole Attack and Its Version\" proposed an alleviation procedure which consists of timely mandate procedure, hole detection algorithm, and sensitive guard procedure to detect the maliciously behaving nodes. It has been observed that the proposed procedure is cost effective and ensures QoS guarantee by assuring resource availability, thus making the MANET appropriate for Internet of Things. Overall, this special issue brought together state of the art research contributions, tutorials, and position papers that address the key aspects of computing information intelligence towards the recent trends and techniques. Venkatesh Jaganathan Balasubramanie Palanisamy Mariofanna Milanova", "author_names": [ "Venkatesh Jaganathan", "Balasubramanie Palanisamy", "Mariofanna G Milanova" ], "corpus_id": 17527752, "doc_id": "17527752", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Recent Trends and Techniques in Computing Information Intelligence", "venue": "TheScientificWorldJournal", "year": 2016 } ]
Peptide–Protein Interactions: From Drug Design toSupramolecular Biomaterials
[ { "abstract": "The self recognition and self assembly of biomolecules are spontaneous processes that occur in Nature and allow the formation of ordered structures, at the nanoscale or even at the macroscale, under thermodynamic and kinetic equilibrium as a consequence of specific and local interactions. In particular, peptides and peptidomimetics play an elected role, as they may allow a rational approach to elucidate biological mechanisms to develop new drugs, biomaterials, catalysts, or semiconductors. The forces that rule self recognition and self assembly processes are weak interactions, such as hydrogen bonding, electrostatic attractions, and van der Waals forces, and they underlie the formation of the secondary structure (e.g. a helix, b sheet, polyproline II helix) which plays a key role in all biological processes. Here, we present recent and significant examples whereby design was successfully applied to attain the desired structural motifs toward function. These studies are important to understand the main interactions ruling the biological processes and the onset of many pathologies. The types of secondary structure adopted by peptides during self assembly have a fundamental importance not only on the type of nano or macro structure formed but also on the properties of biomaterials, such as the types of interaction, encapsulation, non covalent interaction, or covalent interaction, which are ultimately useful for applications in drug delivery.", "author_names": [ "Andrea Caporale", "Simone Adorinni", "Doriano Lamba", "Michele Saviano" ], "corpus_id": 232132050, "doc_id": "232132050", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Peptide Protein Interactions: From Drug Design to Supramolecular Biomaterials", "venue": "Molecules", "year": 2021 }, { "abstract": "Summary A structural database of peptide protein interactions is important for drug discovery targeting peptide mediated interactions. Although some peptide databases, especially for special types of peptides, have been developed, a comprehensive database of cleaned peptide protein complex structures is still not available. Such cleaned structures are valuable for docking and scoring studies in structure based drug design. Here, we have developed PepBDB a curated Peptide Binding DataBase of biological complex structures from the Protein Data Bank (PDB) PepBDB presents not only cleaned structures but also extensive information about biological peptide protein interactions, and allows users to search the database with a variety of options and interactively visualize the search results. Availability and implementation PepBDB is available at http:/huanglab.phys.hust.edu.cn/pepbdb/", "author_names": [ "Zeyu Wen", "Jiahua He", "Huanyu Tao", "Shengyou Huang" ], "corpus_id": 51600791, "doc_id": "51600791", "n_citations": 13, "n_key_citations": 1, "score": 0, "title": "PepBDB: a comprehensive structural database of biological peptide protein interactions", "venue": "Bioinform.", "year": 2019 }, { "abstract": "Fluorinated compounds, while rarely used by nature, are emerging as fundamental ingredients in biomedical research, with applications in drug discovery, metabolomics, biospectroscopy, and, as the focus of this review, peptide/protein engineering. Leveraging the fluorous effect to direct peptide assembly has evolved an entirely new class of organofluorine building blocks from which unique and bioactive materials can be constructed. Here, we discuss three distinct peptide fluorination strategies used to design and induce peptide assembly into nano micro and macro supramolecular states that potentiate high ordered organization into material scaffolds. These fluorine tailored peptide assemblies employ the unique fluorous environment to boost biofunctionality for a broad range of applications, from drug delivery to antibacterial coatings. This review provides foundational tactics for peptide fluorination and discusses the utility of these fluorous directed hierarchical structures as material platforms in diverse biomedical applications.", "author_names": [ "Janna N Sloand", "Scott H Medina" ], "corpus_id": 225367406, "doc_id": "225367406", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Fluorinated peptide biomaterials", "venue": "Peptide science", "year": 2021 }, { "abstract": "The Rosetta Peptiderive protocol identifies, in a given structure of a protein protein interaction, the linear polypeptide segment suggested to contribute most to binding energy. Interactions that feature a 'hot segment' a linear peptide with significant binding energy compared to that of the complex, may be amenable for inhibition and the peptide sequence and structure derived from the interaction provide a starting point for rational drug design. Here we present a web server for Peptiderive, which is incorporated within the ROSIE web interface for Rosetta protocols. A new feature of the protocol also evaluates whether derived peptides are good candidates for cyclization. Fast computation times and clear visualization allow users to quickly assess the interaction of interest. The Peptiderive server is available for free use at http:/rosie.rosettacommons.org/peptiderive.", "author_names": [ "Yuval Sedan", "Orly Marcu", "Sergey Lyskov", "Ora Schueler-Furman" ], "corpus_id": 3743226, "doc_id": "3743226", "n_citations": 38, "n_key_citations": 0, "score": 0, "title": "Peptiderive server: derive peptide inhibitors from protein protein interactions", "venue": "Nucleic Acids Res.", "year": 2016 }, { "abstract": "The dynamic formation of selective protein protein interactions is an essential part of the cellular signal transduction cascades. Although these interactions have a great potential for drug development, disruption of protein protein interactions with small molecules has been proven difficult. We have used a rational approach to map sequences that participate in protein protein interactions and have demonstrated that peptides corresponding to these sequences act as highly specific inhibitors or activators of signalling events and can serve as selective drugs, in basic research and in animal models of human diseases.", "author_names": [ "Daria Mochly-Rosen", "Nir Qvit" ], "corpus_id": 99329540, "doc_id": "99329540", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Peptide inhibitors of protein protein interactions: From rational design to the clinic", "venue": "", "year": 2010 }, { "abstract": "Cyclic peptides are a promising class of bioactive molecules potentially capable of modulating \"difficult\" targets, such as protein protein interactions. Cyclic peptides have long been used as therapeutics derived from natural product derivatives, but remain an underexplored class of compounds from the perspective of rational drug design, possibly due to the known weaknesses of peptide drugs in general. While cyclic peptides are non\"druglike\" by the accepted empirical rules, their unique structure may lend itself to both membrane permeability and proteolytic resistance the main barriers to oral delivery. The constrained shape of cyclic peptides also lends itself better to virtual screening approaches, and new tools and successes in this area have been recently noted. An increasing number of strategies are available, both to generate and screen cyclic peptide libraries, and best practises and current successes are described within. This chapter will describe various computational strategies for virtual screening cyclic peptides, along with known implementations and applications. We will explore the generation and screening of diverse combinatorial virtual libraries, incorporating a range of cyclization strategies and structural modifications. More advanced approaches covered include evolutionary algorithms designed to aid in screening large structural libraries, machine learning approaches, and harnessing bioinformatics resources to bias cyclic peptide virtual libraries towards known bioactive structures.", "author_names": [ "Fergal J Duffy", "Marc Devocelle", "Denis C Shields" ], "corpus_id": 40121783, "doc_id": "40121783", "n_citations": 24, "n_key_citations": 0, "score": 0, "title": "Computational approaches to developing short cyclic peptide modulators of protein protein interactions.", "venue": "Methods in molecular biology", "year": 2015 }, { "abstract": "A summary of the current status of the application of peptidomimetics in cancer therapeutics as an alternative to peptide drugs is provided. Only compounds that are used in therapy or at least under clinical trials are discussed, using inhibitors of farnesyltransferase, proteasome and matrix metalloproteinases as examples. The design and synthesis of peptidomimetics are most important because of the dominant position peptide and protein protein interactions play in molecular recognition and signalling, especially in living systems. The design of peptidomimetics can be viewed from several different perspectives and peptidomimetics can be categorized in a number of different ways. Study of the vast literature would suggest that medicinal and organic chemists, who deal with peptide mimics, utilize these methods in many different ways. Conventional methods used to treat cancer, from non specific chemotherapy to modern molecularly targeted drugs have generated limited results due to the complexity of the disease as well as lack of molecular classes that can be developed into treatments rapidly, easily and economically. Peptidomimetics that are easy to synthesize and optimize and has been studied in different oncology applications as great biologically amenable compounds and can be considered as a promising alternative molecular class for anticancer drug developments. Peptide can be utilized directly as a cytotoxic agent through various mechanisms or can act as a carrier of cytotoxic agents and radioisotopes by specifically targeting cancer cells. Peptide based hormonal therapy has been extensively studied and utilized for the treatment of breast and prostate cancers. Tremendous amount of clinical data is currently available attesting to the efficiency of peptide based cancer vaccines. Keywords Farnesyltransferase inhibitors, Ras, Metal loproteinase inhibitors, Angiogenesis, Proteasome inhibitors.", "author_names": [ "Jeevan R Rajguru", "Sonali A Nagare", "Ashish A Gawai", "Amol G Jadhao", "Mrunal K Shirsat" ], "corpus_id": 204872383, "doc_id": "204872383", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Cancer Chemotherapy with Peptides and Peptidomimetics Drug and Peptide Based Vaccines", "venue": "", "year": 2019 }, { "abstract": "Author(s) Smith, Sarah Jane Advisor(s) Tezcan, F. Akif Abstract: Protein protein interactions are ubiquitous throughout nature at many length and time scales from transient interactions between individual proteins for signaling and electron transfer to the self assembly over large distances of bacterial S layer protein coats. Extensive research has been undertaken to attempt to mimic, interrogate, interrupt, or design protein protein interactions, but natural protein protein interactions often form as a result of many accumulated weak interactions over large, heterogeneous molecular surfaces, making them challenging to design. As a way to overcome these challenges, we have previously introduced methods of synthesizing protein protein interactions with minimal surface design through the directional and highly controllable coordination of metal ions on protein surfaces. The goal of this thesis work has been to expand the scope and functionality of these metal directed protein and peptide interactions. First, we show that, like proteins, short peptides can be directed to fold and assemble in biologically relevant ways using coordination chemistry, while incorporating additional metal based functionality on the peptide backbone. We then extend the scale of protein self assembly to highly ordered, crystalline protein nanotubes with tunable diameters. Finally, we demonstrate the ability to assemble protein DNA nanomaterials in a manner that, similar to what is observed in nature, relies on the sum of a number of weak interactions to form highly ordered protein DNA arrays. Overall, we demonstrate the ability to use metal ions to coordinate interactions on scales as small as single protein protein interactions to as large as micrometer scale arrays. Here, we have expanded the functionality of these metal directed protein and peptide interactions. First, we show that peptides can be directed to fold and assemble in biologically relevant ways using coordination chemistry, while incorporating additional metal based functionality on the peptide backbone. We then extend the scale of assembly to highly ordered, crystalline protein nanotubes with tunable diameters. Finally, we demonstrate the ability to assemble protein DNA nanomaterials in a manner that, similar to what is observed in nature, relies on the sum of a number of weak interactions to form highly ordered protein DNA arrays. Overall, we demonstrate the ability to use metal ions to coordinate interactions on scales as small as single protein protein interactions to as large as micrometer scale arrays.", "author_names": [ "Sarah Jane Smith" ], "corpus_id": 136080880, "doc_id": "136080880", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Metal Controlled Assembly of Peptide and Protein based Engineered Biomaterials", "venue": "", "year": 2016 }, { "abstract": "Background Protein peptide interactions play a fundamental role in a wide variety of biological processes, such as cell signaling, regulatory networks, immune responses, and enzyme inhibition. Peptides are characterized by low toxicity and small interface areas; therefore, they are good targets for therapeutic strategies, rational drug planning and protein inhibition. Approximately 10% of the ethical pharmaceutical market is protein/peptide based. Furthermore, it is estimated that 40% of protein interactions are mediated by peptides. Despite the fast increase in the volume of biological data, particularly on sequences and structures, there remains a lack of broad and comprehensive protein peptide databases and tools that allow the retrieval, characterization and understanding of protein peptide recognition and consequently support peptide design. Results We introduce Propedia, a comprehensive and up to date database with a web interface that permits clustering, searching and visualizing of protein peptide complexes according to varied criteria. Propedia comprises over 19,000 high resolution structures from the Protein Data Bank including structural and sequence information from protein peptide complexes. The main advantage of Propedia over other peptide databases is that it allows a more comprehensive analysis of similarity and redundancy. It was constructed based on a hybrid clustering algorithm that compares and groups peptides by sequences, interface structures and binding sites. Propedia is available through a graphical, user friendly and functional interface where users can retrieve, and analyze complexes and download each search data set. We performed case studies and verified that the utility of Propedia scores to rank promissing interacting peptides. In a study involving predicting peptides to inhibit SARS CoV 2 main protease, we showed that Propedia scores related to similarity between different peptide complexes with SARS CoV 2 main protease are in agreement with molecular dynamics free energy calculation. Conclusions Propedia is a database and tool to support structure based rational design of peptides for special purposes. Protein peptide interactions can be useful to predict, classifying and scoring complexes or for designing new molecules as well. Propedia is up to date as a ready to use webserver with a friendly and resourceful interface and is available at: https:/bioinfo.dcc.ufmg.br/propedia", "author_names": [ "Pedro M Martins", "Lucianna Helene Santos", "Diego Cesar Batista Mariano", "Felippe C Queiroz", "Luana L Bastos", "Isabela de S Gomes", "Pedro H C Fischer", "Rafael E O Rocha", "Sabrina de Azevedo Silveira", "Leonardo H F de Lima", "Mariana T Q de Magalhaes", "Maria G A Oliveira", "Raquel Cardoso de Melo Minardi" ], "corpus_id": 230285569, "doc_id": "230285569", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Propedia: a database for protein peptide identification based on a hybrid clustering algorithm", "venue": "BMC Bioinform.", "year": 2021 }, { "abstract": "A large number of protein protein interactions (PPIs) are mediated by the interactions between proteins and peptide segments in binding partners, and therefore determination of protein peptide interactions (PpIs) is quite crucial to elucidate important biological processes and design peptides or peptidomimetic drugs that can modulate PPIs. Nowadays, as a powerful computation tool, molecular docking has been widely utilized to predict the binding structures of protein peptide complexes. However, although a number of docking programs have been available, the systematic study on the assessment of their performance for PpIs has never been reported. In this study, a benchmark dataset consisting of 185 protein peptide complexes with peptide length ranging from 5 to 20 residues was employed to evaluate the performance of fourteen docking programs, including three protein protein docking programs (ZDOCK, FRODOCK, and HawkDock) three small molecule docking programs (GOLD, Surflex Dock, and AutoDock Vina) and eight protein peptide docking programs (GalaxyPepDock, MDockPeP, HPEPDOCK, CABS dock, pepATTRACT, DINC, AutoDock CrankPep (ADCP) and HADDOCK peptide docking) A new evaluation parameter, named IL_RMSD, was proposed to measure the docking accuracy. In global docking, HPEPDOCK performs the best to the entire dataset and yields the success rates of 4.3% 27.0% and 58.9% at the top 1, 10 and 100 levels, respectively. In local docking, overall, ADCP achieves the best predictions and reaches the success rates of 11.9% 39.5% and 72.4% at the top 1, 10 and 100 levels, respectively. Furthermore, based on the assessment results, HAVM, a new global docking strategy that employed ADCP to optimize the conformations generated by HPEPDOCK and then re ranked these conformations by VoroMQA (a scoring function for protein complexes) was presented, which shows significantly better performance than HPEPDOCK in our benchmark with the success rates of 9.7% 39.5% and 65.9% at the top 1, 10, 100 levels, respectively. It is expected that our work can provide some helpful insights into the selection and development of improved docking programs for PpIs.", "author_names": [ "Gaoqi Weng", "Junbo Gao", "Zhe Wang", "Ercheng Wang", "Xueping Hu", "Xiaojun Yao", "Dongsheng Cao", "Tingjun Hou" ], "corpus_id": 216110781, "doc_id": "216110781", "n_citations": 23, "n_key_citations": 3, "score": 0, "title": "Comprehensive Evaluation of Fourteen Docking Programs on Protein Peptide Complexes and A New Strategy for Improving the Performance of Global Docking.", "venue": "Journal of chemical theory and computation", "year": 2020 } ]
Environmentally friendly Green complexing agent CMP
[ { "abstract": "Solution processed Cu2ZnSnS4 (CZTS) thin film growth parameters using complexing agent triethanolamine (TEA) have been optimized. Effects of TEA on structural, morphological, optical and electrical properties of CZTS thin films were systematically investigated. X ray diffraction and Raman spectroscopy of annealed CZTS thin films confirmed a pure kesterite structure with optimized TEA concentration. Surface morphology of CZTS films were analyzed by field emission scanning electron microscope and atomic force microscope, which revealed a smooth surface and systematic grain growth formation with varying TEA concentrations. p Type conductivity was confirmed using Hall measurements and the effect of TEA concentration on electrical properties is investigated. X ray photoelectron spectroscopy demonstrated absence of secondary phases and stoichiometric atomic ratios of multicationic quaternary CZTS thin film grown without sulphurization. UV Vis spectra revealed a direct energy band gap ranging from 1.90 to 1.40 eV, which was found to depend upon the TEA concentration. Such band gap values are optimum for semiconductor material as an absorber layer of thin film solar cells. The CZTS thin film was further used for the fabrication of a solar cell of structure SLG/FTO/ZnO/CZTS/Al. The best solar cell showed a short circuit current density (Jsc) of 10.78 mA/cm2, open circuit voltage (Voc) of 0.27 V, fill factor (FF) of 37% and power conversion efficiency (e) of 1.08% under air mass 1.5 (100 mW cm 2) illumination.", "author_names": [ "J J Chaudhari", "Utpal S Joshi" ], "corpus_id": 104264135, "doc_id": "104264135", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Effects of complexing agent on earth abundant environmentally friendly Cu2ZnSnS4 thin film solar cells prepared by sol gel deposition", "venue": "", "year": 2018 }, { "abstract": "Electrochemical behaviors of a silver complex in an environmentally friendly silver plating bath with 5,5 dimethylhydantoin (DMH) and nicotinic acid (NA) as complexing agents were investigated in this paper. Like the cyanide based silver electroplating bath, silver deposits with smooth and compact morphologies, as well as high purity could be obtained from the studied DMH and NA based silver electroplating bath. The electrochemical behaviors of the silver complex in this cyanide free silver electroplating were studied by cyclic voltammetry with different sweep rates to investigate the discharge process of the silver plating bath, the transfer coefficients and diffusion coefficient of the silver complex in this bath. The results of the chronoamperometry on a glass carbon electrode indicate that the nucleation processes of silver from the bath is a three dimensional progressive nucleation process, and the growth of silver nucleation and the nucleation rate of silver deposit in the DMH and NA based silver plating bath were highly dependent on the applied potential.", "author_names": [ "Anmin Liu", "Xuefeng Ren", "Jie Zhang", "Dongqing Li", "Mao-zhong An" ], "corpus_id": 101813734, "doc_id": "101813734", "n_citations": 11, "n_key_citations": 1, "score": 0, "title": "Complexing agent study for environmentally friendly silver electrodeposition(II) electrochemical behavior of silver complex", "venue": "", "year": 2016 }, { "abstract": "Green synthesis of nanoparticles can be an important alternative compared to conventional physio chemical synthesis. We utilized Scadoxus multiflorus leaf powder aqueous extract as a capping and stabilizing agent for the synthesis of pure zinc oxide nanoparticles (ZnO NPs) Further, the synthesized ZnO NPs were subjected to various characterization techniques. Transmission electron microscope (TEM) analysis showed an irregular spherical shape, with an average particle size of 31 2 nm. Furthermore, the synthesized ZnO NPs were tested against Aedes aegypti larvae and eggs, giving significant LC50 value of 34.04 ppm. Ovicidal activity resulted in a higher percentage mortality rate of 96.4 0.24 at 120 ppm with LC50 value of 32.73 ppm. Anti fungal studies were also conducted for ZnO NPs against Aspergillus niger and Aspergillus flavus, which demonstrated a higher inhibition rate for Aspergillus flavus compared to Aspergillus niger.", "author_names": [ "Naif Abdullah Al-Dhabi", "Mariadhas Valan Arasu" ], "corpus_id": 51609363, "doc_id": "51609363", "n_citations": 55, "n_key_citations": 1, "score": 0, "title": "Environmentally Friendly Green Approach for the Production of Zinc Oxide Nanoparticles and Their Anti Fungal, Ovicidal, and Larvicidal Properties", "venue": "Nanomaterials", "year": 2018 }, { "abstract": "In this paper, we introduce a new environmentally friendly silver electroplating bath, employing 5,5 dimethylhydantoin (DMH) and nicotinic acid (NA) as complexing agents, based on the prediction of computational chemistry. An excellent silver electrodeposit with properties suitable for application in electronics packaging was obtained from the newly developed silver electroplating bath, and the electroplating bath is simple and stable. Moreover, the silver(I) complexes in this bath possessed good complex stability. As a consequence, mirror bright silver electrodeposits on copper substrates with excellent leveling capability, smooth and compact morphologies, high purity and conductivity, as well as excellent welding property could be realized by adopting this unique bath. Based on the performances of the plating bath and silver deposit, the introduced silver plating bath is a promising candidate for silver electrodeposition applied in microelectronics to replace the conventional cyanide silver electroplating baths.", "author_names": [ "Anmin Liu", "Xuefeng Ren", "Buguo Wang", "Jingping Zhang", "Peixia Yang", "Jin-qiu Zhang", "Mao-zhong An" ], "corpus_id": 95106704, "doc_id": "95106704", "n_citations": 27, "n_key_citations": 1, "score": 0, "title": "Complexing agent study via computational chemistry for environmentally friendly silver electrodeposition and the application of a silver deposit", "venue": "", "year": 2014 }, { "abstract": "One dimensional semiconductor nanofibers have been regarded as one of the most promising building blocks for next generation electronic devices. Among these semiconductor nanofibers, tin oxide (SnO2) has been regarded as an attractive alternative for field effect transistors (FETs) due to its high abundance, nontoxicity and low cost. However, the electronic devices based on electrospun SnO2 nanofibers suffer from poor interfacial property and inferior performance. Here, we have proposed that the introduction of Y can be used to reduce the O vacancies in the channel layers and ethanolamine (EA) is selected as a complexing agent to enhance the interface property. It is confirmed that the SnYO nanofiber FETs based on the addition of EA exhibit better electrical performance, including a mobility of 2.70 cm2 V 1 s 1 and a threshold voltage of 2.3 V. When the high k ZrAlOx films are applied in FETs as dielectric layers, the SnYO nanofiber FETs exhibit optimized electrical performance with an acceptable mobility of 4.78 cm2 V 1 s 1, a small threshold voltage of 0.72 V and a suitable on/off current ratio of ~107. This work presents a simple and low cost EA treatment method to improve the electrical performance, which provides a new perspective for commercial products based on electrospun nanofibers.", "author_names": [ "Jingguo Li", "Qi Chen", "Yaohua Yang", "Wenqing Zhu", "Xifeng Li", "Jianhua Zhang" ], "corpus_id": 216318564, "doc_id": "216318564", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Amelioration of interfacial combination and suppression of oxygen vacancies for high performance environmentally friendly electrospun SnYO nanofiber field effect transistors", "venue": "", "year": 2020 }, { "abstract": "In this work, an environmentally friendly leaching process for the recovery of indium (In) and tin (Sn) from LCD panel waste was investigated. Easily degradable citrates (C6H5O73 i.e. sodium citrate and citric acid, were used as complexing agents. The morphology and composition of the species present in the LCD powder before and after the leaching processes were characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) The concentrations of In, Sn, and iron (Fe) present in the leachate were determined by atomic absorption spectrometry (AAS) The necessary thermodynamic conditions for achieving substantial In recovery were established by using MEDUSA software. The optimal process conditions were determined experimentally by varying the initial citrate concentration as well as by using reducing or oxidizing media, respectively hydrazine (N2H4) or hydrogen peroxide (H2O2) It was found that using N2H4 in a citrate solution as a reducing agent enhances the leaching efficiency. However, high concentrations of Sn and Fe with respect to In were found in the LCD powder. Therefore, a pretreatment processes to first remove the excess of Sn and Fe, which compete with In for the citrate, was implemented. Leaching with 1 M citrate, 0.2 M N2H4, at pH 5, using sodium hydroxide (NaOH) at solid:liquid (S:L) ratio of 20 gL 1, yielded a remarkably high In recovery of 98.9% after 16.6 h.", "author_names": [ "Adrian Lopez-Yanez", "Alejandro R Alonso", "Alejandra Vengoechea-Pimienta", "Jorge Ramirez-Munoz" ], "corpus_id": 199436863, "doc_id": "199436863", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Indium and tin recovery from waste LCD panels using citrate as a complexing agent.", "venue": "Waste management", "year": 2019 }, { "abstract": "While lithium sulfur batteries (Li S) hold promise as future high energy density low cost energy storage systems, barriers to implementation include low sulfur loading, limited cycle life, and the use of toxic electrolyte solvents. A comprehensive study of Li S cells in the environmentally benign di(propylene glycol) dimethyl ether (DPGDME) based electrolyte, using as prepared MoS2 nanosheets derived from a facile aqueous microwave synthesis as polysulfide trapping agents, is reported herein for the first time. Conventional coated foil electrodes and binder free electrodes (BFEs) with various structures are systematically generated and tested to correlate electrode design with the resulting electrochemical behavior. Significantly improved Li S electrochemistry is demonstrated through the synergy of MoS2 chemistry and binder free electrode engineering. In the coating configuration, the MoS2 containing cell evinced better rate performance and more stable cyclability than the cell without MoS2. In comparison.", "author_names": [ "Li-xi Wang", "Alyson Abraham", "Diana M Lutz", "Calvin D Quilty", "Esther S Takeuchi", "Kenneth J Takeuchi", "Amy C Marschilok" ], "corpus_id": 104411619, "doc_id": "104411619", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Toward Environmentally Friendly Lithium Sulfur Batteries: Probing the Role of Electrode Design in MoS2 Containing Li S Batteries with a Green Electrolyte", "venue": "ACS Sustainable Chemistry Engineering", "year": 2019 }, { "abstract": "The invention relates to an environmentally friendly chemical deplating agent for a nickel plating and a deplating method. The deplating agent comprises the components of 30 g/L to 100 g/L of sulfuric acid, 30 g/L to 140 g/L of oxalic acid, 10 g/L to 30 g/L of sodium citrate, 10 g/L to 60 g/L of sodium acetate, 15 g/L to 60 g/L of sodium gluconate, and the balance being water. According to the environmentally friendly chemical deplating agent, oxalic acid is added based on sulfuric acid, acidity of oxalic acid is not high, and overetching of the nickel plating can be prevented; oxalic acid can provide hydrogen ions used for corroding the plating, and the deplating purpose of the nickel plating can be achieved through only a relatively small amount of sulfuric acid; deplating speed is high, efficiency is high, a deplated stainless steel matrix is smooth in surface, overetching is avoided, and follow up reutilization and processing are not affected; and oxalate and nickel ions generate nickel oxalate sediment through complexing, nickel is directly sedimented and separated from the system, the follow up step of recycling nickel metal from deplating waste water is eliminated, nickel oxalate can be directly recycled, and utilization is convenient.", "author_names": [ "" ], "corpus_id": 133035705, "doc_id": "133035705", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Environmentally friendly chemical deplating agent for nickel plating and deplating method", "venue": "", "year": 2017 }, { "abstract": "An effective and environmentally friendly recycling process designed for LiCoO2 cathode powders of spent Li ion batteries using mixture of mild organic acids, citric acid (CA) tartaric acid (TA) and ascorbic acid (AA) to recover the metals. Almost complete dissolution of Li and nearly 90% dissolution of Co occurred in at 80 degC for 6 h. The reducing agent, ascorbic acid (AA) converts the dissolved Co(III) to Co(II) thereby selective recovery of Co as Co(II) oxalate is possible. The formation of Co(III) and Co(II) complex is evident from the UV Vis spectra of the dissolved solution as a function of dissolution time. Thus, the reductive complexing dissolution mechanism is proposed here. These mild organic acids are environmentally benign unlike the mineral acids.", "author_names": [ "G P Nayaka", "Yingjie Zhang", "Peng Dong", "Ding-Teng Wang", "Karkala Vasantakumar Pai", "J Manjanna", "G V N Santhosh", "Jianguo Duan", "Zhongren Zhou", "Jie Xiao" ], "corpus_id": 102742893, "doc_id": "102742893", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Effective and environmentally friendly recycling process designed for LiCoO2 cathode powders of spent Li ion batteries using mixture of mild organic acids.", "venue": "Waste management", "year": 2018 }, { "abstract": "Abstract The planarization property of slurry is a crucial factor in evaluating the quality of the copper (Cu) film chemical mechanical polishing (CMP) process. Various chemical additives of amino acids have been widely used in semiconductor and microelectronics industries to develop novel CMP slurries owing to their pollution free and high performance characteristics. In this paper, sarcosine was served as a crucial chemical additive in Cu film slurries. Through electrochemical measurements, X ray photoelectron spectroscopy, Ultraviolet visible, and Raman spectra tests, it was revealed that sarcosine could react with cupric ions in a ratio of 4:1 to form a stable water soluble Cu sarcosine complex, which can accelerate the chemical dissolution of Cu surface during CMP process, and it was also found that the complexing effect was relatively weak. Moreover, various tests on Cu wafers showed that high Cu removal rate (RR) low Cu static etching rate (SER) and ideal surface quality could be realized when sarcosine was used as an auxiliary complexing agent in glycine based Cu slurries. The purpose of such a study is to find an environmentally friendly chemical additive that can improve the performance of slurry in the manufacturing process of Cu film and other materials used in integrated circuits.", "author_names": [ "Jiakai Zhou", "Xinhuan Niu", "Chenghui Yang", "Zhaoqing Huo", "Yanan Lu", "Zhi Feng Wang", "Yaqi Cui", "Ru Wang" ], "corpus_id": 224868467, "doc_id": "224868467", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Surface action mechanism and planarization effect of sarcosine as an auxiliary complexing agent in copper film chemical mechanical polishing", "venue": "", "year": 2020 } ]
Coupling of quantum dots and cavities
[ { "abstract": "We investigate the effect of decoherence mechanisms in semiconductor quantum dot cavity systems by performing photoluminescence measurements of InGaAs/GaAs site controlled quantum dots coupled to photonic crystal cavities and comparing the results to a theoretical model.", "author_names": [ "C Jarlov", "Etienne Wodey", "A Lyasota", "Milan Calic", "Pascal Gallo", "Benjamin Dwir", "Alok P Rudra", "E Kapon" ], "corpus_id": 20012077, "doc_id": "20012077", "n_citations": 21, "n_key_citations": 1, "score": 0, "title": "Effect of pure dephasing and phonon scattering on the coupling of semiconductor quantum dots to optical cavities", "venue": "2015 Conference on Lasers and Electro Optics (CLEO)", "year": 2015 }, { "abstract": "Quantum electrodynamics is rapidly finding a set of new applications in thresholdless lasing, photochemistry, and quantum entanglement due to the development of sophisticated patterning techniques to couple nanoscale photonic emitters with photonic and plasmonic cavities. Colloidal and epitaxial semiconductor nanocrystals or quantum dots (QDs) are promising candidates for emitters within these architectures but are dramatically less explored in this role than are molecular emitters. This perspective reviews the basic physics of emitter cavity coupling in the weak to strong coupling regimes, describes common architectures for these systems, and lists possible applications (in particular, photochemistry) with a focus on the advantages and issues associated with using QDs as the emitters.", "author_names": [ "Dana E Westmoreland", "Kevin P McClelland", "Kaitlyn A Perez", "James C Schwabacher", "Zhengyi Zhang", "Emily A Weiss" ], "corpus_id": 209317678, "doc_id": "209317678", "n_citations": 8, "n_key_citations": 0, "score": 1, "title": "Properties of quantum dots coupled to plasmons and optical cavities.", "venue": "The Journal of chemical physics", "year": 2019 }, { "abstract": "Strong coupling originating from excitons of quantum dots and plasmons in nanocavities can be realized at room temperature due to the large electromagnetic field enhancement of plasmons, offering building blocks for quantum information systems, ultralow power switches and lasers. However, most of the current strong coupling effects were realized by the interaction between excitons and far field light excited bright plasmon modes in the visible range. Beyond that, there is still a lack of direct imaging of polariton modes at the nanoscale. In this work, by using cathodoluminescence, ultrastrong coupling with Rabi splitting exceeding 1 eV between bonding breathing plasmons of aluminum (Al) metal insulator metal (MIM) cavities and excited states of CdZnS/ZnS quantum dots was observed in the near ultraviolet (UV) spectrum. Further, the hybridization of the QDs excitons and bonding breathing plasmonic modes is verified by deep subwavelength images of polaritonic modes in real space. Analytic analysis based on the coupled oscillator model and full wave electromagnetic simulations is consistent with our experimental results. Our work not only indicates the great potential of electron excited plasmon modes for strong coupling applications, but also extends the polaritonic frequency to the UV range with Al nanocavities.", "author_names": [ "Liangwan Li", "Lei Wang", "Chenglin Du", "Zhongyuan Guan", "Yinxiao Xiang", "Wei Wu", "Mengxin Ren", "Xinzheng Zhang", "Aiwei Tang", "Wei Cai", "Jingjun Xu" ], "corpus_id": 210863830, "doc_id": "210863830", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Ultrastrong coupling of CdZnS/ZnS quantum dots to bonding breathing plasmons of aluminum metal insulator metal nanocavities in near ultraviolet spectrum.", "venue": "Nanoscale", "year": 2020 }, { "abstract": "Confining light in extremely small cavities is crucial in nanophotonics, central to many applications. Employing a unique nanoparticle on mirror plasmonic structure and using graphene film as spacer, we create nanoscale cavities with volumes of only a few tens of cubic nanometers. The ultracompact cavity produces extremely strong optical near fields, which facilitate the formation of single carbon quantum dot in the cavity and simultaneously empowers the strong coupling between the excitons of the formed carbon quantum dot and the localized surface plasmons. This is manifested in the optical scattering spectra, showing magnificent Rabi splitting up to 200 meV at ambient conditions. In addition, we demonstrate that the strong coupling is tuneable with light irradiation. This opens new paradigms of investigating the fundamental light emission properties of carbon quantum dots in the quantum regime and paves the way for many significant applications.", "author_names": [ "Joel M Katzen", "Christos Tserkezis", "Qiran Cai", "Luhua Li", "Gaehang Lee", "Gi-Ra Yi", "W R Hendren", "Elton J G Santos", "Robert M Bowman", "Fumin Huang" ], "corpus_id": 215600625, "doc_id": "215600625", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Strong coupling of carbon quantum dots in plasmonic nanocavities.", "venue": "ACS applied materials interfaces", "year": 2020 }, { "abstract": "", "author_names": [ "T Tian Xia" ], "corpus_id": 136416722, "doc_id": "136416722", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Controlled coupling of semiconductor quantum dots to optical micro cavities", "venue": "", "year": 2015 }, { "abstract": "We report a study of single quantum dots inside photonic crystal cavities with a low temperature scanning near field optical microscope. The spatial maps of single excitonic lines from the quantum dot show the clear signature of coupling to the cavity modes for small detunings. We also show that the near field tip can be used to control the exciton photon coupling at the nanoscale. A general framework for the interpretation of near field maps of single emitters in cavities is proposed.", "author_names": [ "Matthias Skacel", "Francesco Pagliano", "Thang Ba Hoang", "Leonardo Midolo", "Sartoon Fattahpoor", "Lianhe Li", "Edmund H Linfield", "Andrea Fiore" ], "corpus_id": 52206357, "doc_id": "52206357", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Coupling of single quantum dots to photonic crystal cavities investigated by low temperature scanning near field optical microscopy", "venue": "", "year": 2013 }, { "abstract": "Solid state single photon sources with high purity, high brightness and a large degree of linear polarization are appealing to photonic quantum technologies. However, high performance single photon sources based on InAs/GaAs quantum dots (QDs) so far are operating at near infrared range, which limits the detection efficiency and potential compatibility with atomic quantum memory in visible. Here, we explore GaAs droplet epitaxial QDs emitting in visible to achieve bright, pure and highly polarized single photon emission via coupling to photonic crystal cavities.", "author_names": [ "Yuming Wei", "Tianming Zhao", "Beimeng Yao", "Rongbin Su", "Ying Yu", "Jin Liu", "Xuehua Wang" ], "corpus_id": 213822164, "doc_id": "213822164", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Bright and highly polarized single photon sources in visible based on droplet epitaxial GaAs quantum dots in photonic crystal cavities", "venue": "", "year": 2019 }, { "abstract": "We present rigorous and intuitive master equation models to study on demand single photon sources from pulse excited quantum dots coupled to cavities. We consider three methods of source excitation: resonant pi pulse, off resonant phonon assisted inversion, and two photon excitation of a biexciton exciton cascade, and investigate the effect of the pulse excitation process on the quantum indistinguishability, efficiency, and purity of emitted photons. By explicitly modelling the time dependent pulsed excitation process in a manner which captures non Markovian effects associated with coupling to photon and phonon reservoirs, we find that photons of near unity indistinguishability can be emitted with over 90% efficiency for all these schemes, with the off resonant schemes not necessarily requiring polarization filtering due to the frequency separation of the excitation pulse, and allowing for very high single photon purities. Furthermore, the off resonant methods are shown to be robust over certain parameter regimes, with less stringent requirements on the excitation pulse duration in particular. We also derive a semi analytical simplification of our master equation for the off resonant drive, which gives insight into the important role that exciton phonon decoupling for a strong drive plays in the off resonant phonon assisted inversion process", "author_names": [ "Chris Gustin", "Stephen H Hughes" ], "corpus_id": 189928069, "doc_id": "189928069", "n_citations": 10, "n_key_citations": 2, "score": 0, "title": "Efficient Pulse Excitation Techniques for Single Photon Sources from Quantum Dots in Optical Cavities", "venue": "Advanced Quantum Technologies", "year": 2019 }, { "abstract": "The control of quantum coupling between nano objects is essential to quantum technologies. Confined nanostructures, such as cavities, resonators, or quantum dots, are designed to enhance interactions between electrons, photons, or phonons, giving rise to new properties, on which devices are developed. The nature and strength of these interactions are often measured indirectly on an assembly of dissimilar objects. Here, we adopt an innovative point of view by directly mapping the coupling of single nanostructures using scanning tunneling microscopy and spectroscopy (STM and STS) We take advantage of the unique capabilities of STM/STS to map simultaneously the nano object's morphology and electronic density in order to observe in real space the electronic coupling of pairs of In(Ga)As/GaAs self assembled quantum dots (QDs) forming quantum dot molecules (QDMs) Differential conductance maps d I/d V E, x, y) demonstrate the presence of an effective electronic coupling, leading to bonding and antibonding states, even for dissymmetric QDMs. The experimental results are supported by numerical simulations. The actual geometry of the QDMs is taken into account to determine the strength of the coupling, showing the crucial role of quantum dot size and pair separation for device growth optimization.", "author_names": [ "Guillemin Rodary", "Lorenzo Bernardi", "Christophe David", "Bruno Fain", "Aristide Lemaitre", "Jean Christophe Girard" ], "corpus_id": 135446818, "doc_id": "135446818", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Real Space Observation of Electronic Coupling between Self Assembled Quantum Dots.", "venue": "Nano letters", "year": 2019 }, { "abstract": "In this paper, the properties of emission spectra of dissipative cavities coupled with quantum dots were studied. The effects of the cavity incoherent pump rate on the emission spectra of the system are discussed. We found that the incoherent pump rate can enhance the fluorescence emission in dissipative cavities coupled with quantum dots and the result can be confirmed in experiment. In addition, the effects of the coupling strengths between quantum dot and cavity field, and between the two cavities on the emission spectra of the system also are discussed. Our results show that in the case of no matter resonance or off resonance, the triple peaks should occur in theory when the single mode cavity coupled with a double level system is affected by external coherent fields and we also demonstrate that the Rabi splitting increases with the coupling strengths between quantum dot and cavity field or between the two cavities increase.", "author_names": [ "Yang Zhang", "Shu-chen Lu" ], "corpus_id": 150118323, "doc_id": "150118323", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Emission spectrum in dissipative cavities coupled with quantum dots", "venue": "Journal of Physics B: Atomic, Molecular and Optical Physics", "year": 2019 } ]
Uranium nitride carbon
[ { "abstract": "Herein, for the first time, the authors report metal free heterojunction photocatalysts consisting of push pull conjugated polymers and polymeric carbon nitride (CN) for efficient reduction of uranium. Furthermore, the authors innovatively proposed a heteroatomic engineering strategy to further improve the visible light capture ability and separation of electron hole pairs of heterojunction photocatalysts via replacing carbon atoms in donors by nitrogen atoms. The result revealed that in the photocatalytic reduction of uranium, the kinetic constant of PFB/CN (0.037 min 1) was 2.47 times higher than that of CN (0.015 min 1) Notably, copolymerization of a nitrogen containing electron donor carbazole unit into the polymer backbone would further widen the light response range and promote electron hole separation within PCB/CN as compared to PFB/CN, leading to a higher kinetic constant (0.049 min 1) 3.27 times higher than that of CN. The current work underlines that adapting a reasonable heteroatomic engineering strategy for polymer heterojunctions is a remarkably effective strategy to develop up and coming organic semiconductor photocatalysts for efficient reduction of uranium.", "author_names": [ "Fengtao Yu", "Zhenzhen Xu", "Jianbo Xiong", "Qiangwen Fan", "Xue-feng Feng", "Yuan Tao", "Jianli Hua", "Feng Luo" ], "corpus_id": 216324654, "doc_id": "216324654", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Heteroatom engineering of polymeric carbon nitride heterojunctions for boosting photocatalytic reduction of hexavalent uranium", "venue": "", "year": 2020 }, { "abstract": "Enrichment of UVI is an urgent project for nuclear energy development. Herein, magnetic graphitic carbon nitride nanosheets were successfully prepared by in situ anchoring of pyrrhotite (Fe7 S8 on the graphitic carbon nitride nanosheet (CNNS) which were used for capturing UVI The structural characterizations of Fe7 S8 /CNNS 1 indicated that the CNNS could prevent the aggregation of Fe7 S8 and the saturation magnetization was 4.69 emu g 1 which meant that it was easy to separate the adsorbent from the solution. Adsorption experiments were performed to investigate the sorption properties. The results disclosed that the sorption data conformed to the Langmuir isotherm model with the maximum adsorption capacity of 572.78 mg g 1 at 298 K. The results of X ray photoelectron spectroscopy (XPS) demonstrated that the main adsorption mechanism are as follows: UVI is adsorbed on the surface of Fe7 S8 /CNNS 1 through surface complexation initially, then it was reduced to insoluble UIV Thereby, this work provided an efficient and easy to handle sorbent material for extraction of UVI", "author_names": [ "Xuan Hao", "Hongsen Zhang", "Qi Liu", "Jingyuan Liu", "Rongrong Chen", "Jing Yu", "Milin Zhang", "Peili Liu", "Jun Wang" ], "corpus_id": 53092476, "doc_id": "53092476", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "In Situ Anchoring of Pyrrhotite on Graphitic Carbon Nitride Nanosheet for Efficient Immobilization of Uranium.", "venue": "Chemistry", "year": 2019 }, { "abstract": "Abstract The natural crab shell with the unique structure consisting of CaCO3 was employed as the biotemplate encapsulating urea to form porous g C3N4 for U(VI) elimination. A multiscale characterization of porous g C3N4 provided evidences for successfully introducing porous structure with increased surface area as well as multi sorption sites (e.g. C N C, N (C)3 and C N H groups) The interaction of U(VI) with porous g C3N4 was investigated by batch experiments, spectroscopic analyses and theoretical calculations. The sorption experiments indicated that g C3N4 550 with the highest polymerization exhibited rapidly sequestering U(VI) within 120 min and superior uptake performance (149.70 mg/g) at pH 5.0. The presence of U N shell (R 2.80 A) calculated from EXAFS spectra revealed the U(VI) immobilization on g C3N4 550 at pH 5.0 was ascribed to the inner sphere surface complexation. The DFT calculations further evidenced the strong interaction between uranyl and g C3N4 (Ead 156.83 kcal/mol) and the most effective sorption site was inside the holes of g C3N4. The superior uranium sorption ability along with low cost and environmental friendly raw materials pointed to the high potential of porous g C3N4 for uranium preconcentration. The findings will expand an exciting direction towards the effective removal of actinides in environmental cleanup.", "author_names": [ "Chen-lu Zhang", "Yang Liu", "Xiaoguang Li", "Hong-xia Chen", "Tao Wen", "Zhihao Jiang", "Yuejie Ai", "Yubing Sun", "Tasawar Hayat", "Xiangke Wang" ], "corpus_id": 102692838, "doc_id": "102692838", "n_citations": 43, "n_key_citations": 0, "score": 0, "title": "Highly uranium elimination by crab shells derived porous graphitic carbon nitride: Batch, EXAFS and theoretical calculations", "venue": "", "year": 2018 }, { "abstract": "The reactivity of terminal uranium(V/VI) nitrides with CE2 (E=O, S) is presented. Well defined C=E cleavage followed by zero one and two electron redox events is observed. The uranium(V) nitride [U(TrenTIPS (N)[K(B15C5)2 (1, TrenTIPS =N(CH2 CH2 NSiiPr3 )3 B15C5=benzo 15 crown 5) reacts with CO2 to give [U(TrenTIPS (O)(NCO)[K(B15C5)2 (3) whereas the uranium(VI) nitride [U(TrenTIPS (N) (2) reacts with CO2 to give isolable [U(TrenTIPS (O)(NCO) (4) complex 4 rapidly decomposes to known [U(TrenTIPS (O) (5) with concomitant formation of N2 and CO proposed, with the latter trapped as a vanadocene adduct. In contrast, 1 reacts with CS2 to give [U(TrenTIPS (k2 CS3 [K(B15C5)2 (6) 2, and [K(B15C5)2 [NCS] (7) whereas 2 reacts with CS2 to give [U(TrenTIPS (NCS) (8) and \"S\" with the latter trapped as Ph3 PS. Calculated reaction profiles reveal outer sphere reactivity for uranium(V) but inner sphere mechanisms for uranium(VI) despite the wide divergence of products the initial activation of CE2 follows mechanistically related pathways, providing insight into the factors of uranium oxidation state, chalcogen, and NCE groups that govern the subsequent divergent redox reactions that include common one electron reactions and a less common two electron redox event. Caution, we suggest, is warranted when utilising CS2 as a reactivity surrogate for CO2", "author_names": [ "Peter A Cleaves", "Christos E Kefalidis", "Benedict M Gardner", "Floriana Tuna", "Eric J L McInnes", "William Lewis", "Laurent Maron", "Stephen T Liddle" ], "corpus_id": 205625385, "doc_id": "205625385", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Terminal Uranium(V/VI) Nitride Activation of Carbon Dioxide and Carbon Disulfide: Factors Governing Diverse and Well Defined Cleavage and Redox Reactions.", "venue": "Chemistry", "year": 2017 }, { "abstract": "Abstract Thermodynamic simulation demonstrated that the accumulation of fission products in irradiation of a uranium plutonium nitride with admixture of carbon and oxygen (U 0.8 Pu 0.2 (N 0.9475 O 0.02625 C 0.02625 results in that a multicomponent oxycarbonitride solid solution is formed. This solid solution contains U, Pu,Am, Np, Zr, Y, and lanthanides as well as separate oxide (BaUO 3 SrPuO 3 carbide (URu 3 C 0.7 Mo 2 C) and nitride (U 2 N 3 phases and intermetallides U(Rh,Pd) 3 The b decay of metallic radionuclides in separate oxide and carbide phases of spent nuclear fuel changes their chemical and phase compositions, The transformation kinetics of separate phases 99 Mo 2 C 1/ 399 Tc 6 C 2/3 C, 140 BaUO 3 1/2 140 Ce 2 UO 6 1/2U was calculated.", "author_names": [ "D Yu Lyubimov", "G S Bulatov", "Konstantin E German" ], "corpus_id": 232117674, "doc_id": "232117674", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Comparative Analysis of the Phase Composition of Irradiated Uranium Plutonium Nitride under Joint Influence of Carbon and Oxygen Impurities and b Decomposition of Some Fission Products", "venue": "Radiochemistry", "year": 2021 }, { "abstract": "Abstract Extracting uranium from high salinity seawater at ultralow concentrations would beneficially contribute to the sustainable utilization of nuclear energy, but it poses a significant challenge. Here we report a sunlight driven photocatalysis assisted extraction (SUPER) method by utilizing a bifunctional carbon nitride material, CN550, which has shown about a tenfold improvement in both adsorption capacity and photocatalytic activity compared to g C3N4. Uranyl ions could be captured on the surface of CN550, and then deposited as metastudtite nanoparticles with light illumination. Compared with the pure physicochemical adsorption (PA) method, a tenfold higher uranium extraction capacity, up to 1556 mg g 1, has been attained. Additionally, a 25 times improvement of the partition coefficient (PC) from 0.312 to 7.778 L g 1, has also been achieved. In spiked real seawater, the extraction capacity can still achieve more than 1000 mg g 1, and the SUPER method has been found to work under natural sunlight illumination as well.", "author_names": [ "Shuang Liu", "Zhe Wang", "Yuexiang Lu", "Hongpeng Li", "Xianjie Chen", "Guoyu Wei", "Tong Wu", "Daniel-James Maguire", "Gang Ye", "Jing Chen" ], "corpus_id": 224949768, "doc_id": "224949768", "n_citations": 9, "n_key_citations": 0, "score": 1, "title": "Sunlight induced uranium extraction with triazine based carbon nitride as both photocatalyst and adsorbent", "venue": "", "year": 2021 }, { "abstract": "Cleavage of dihydrogen is an important step in the industrial and enzymatic transformation of N2 into ammonia. The reversible cleavage of dihydrogen was achieved under mild conditions (room temperature and 1 atmosphere of H2 by the molecular uranium nitride complex, [Cs{U(OSi(Ot Bu)3 )3 }2 (m N) 1, leading to a rare hydride imide bridged diuranium(IV) complex, [Cs{U(OSi(Ot Bu)3 )3 }2 (m H)(m NH) 2 that slowly releases H2 under vacuum. This complex is highly reactive and quickly transfers hydride to acetonitrile and carbon dioxide at room temperature, affording the ketimide and formate bridged UIV species [Cs{U(OSi(Ot Bu)3 )3 }2 (m NH)(m CH3 CHN) 3 and [Cs{U(OSi(Ot Bu)3 )3 }2 (m HCOO)(m NHCOO) 4.", "author_names": [ "Marta Falcone", "Lok Nga Poon", "Farzaneh Fadaei Tirani", "Marinella Mazzanti" ], "corpus_id": 7465767, "doc_id": "7465767", "n_citations": 39, "n_key_citations": 0, "score": 0, "title": "Reversible Dihydrogen Activation and Hydride Transfer by a Uranium Nitride Complex.", "venue": "Angewandte Chemie", "year": 2018 }, { "abstract": "Molecular nitrogen (N2) is cheap and widely available, but its unreactive nature is a challenge when attempting to functionalize it under mild conditions with other widely available substrates (such as carbon monoxide, CO) to produce value added compounds. Biological N2 fixation can do this, but the industrial Haber Bosch process for ammonia production operates under harsh conditions (450 degrees Celsius and 300 bar) even though both processes are thought to involve multimetallic catalytic sites. And although molecular complexes capable of binding and even reducing N2 under mild conditions are known, with co operativity between metal centres considered crucial for the N2 reduction step, the multimetallic species involved are usually not well defined, and further transformation of N2 binding complexes to achieve N H or N C bond formation is rare. Haber noted, before an iron based catalyst was adopted for the industrial Haber Bosch process, that uranium and uranium nitride materials are very effective heterogeneous catalysts for ammonia production from N2. However, few examples of uranium complexes binding N2 are known, and soluble uranium complexes capable of transforming N2 into ammonia or organonitrogen compounds have not yet been identified. Here we report the four electron reduction of N2 under ambient conditions by a fully characterized complex with two Uiii ions and three K+ centres held together by a nitride group and a flexible metalloligand framework. The addition of H2 and/or protons, or CO to the resulting complex results in the complete cleavage of N2 with concomitant N2 functionalization through N H or N C bond forming reactions. These observations establish that a molecular uranium complex can promote the stoichiometric transformation of N2 into NH3 or cyanate, and that a flexible, electron rich, multimetallic, nitride bridged core unit is a promising starting point for the design of molecular complexes capable of cleaving and functionalizing N2 under mild conditions.", "author_names": [ "Marta Falcone", "Lucile Chatelain", "Rosario Scopelliti", "Ivica Zivkovic", "Marinella Mazzanti" ], "corpus_id": 4407384, "doc_id": "4407384", "n_citations": 118, "n_key_citations": 0, "score": 1, "title": "Nitrogen reduction and functionalization by a multimetallic uranium nitride complex", "venue": "Nature", "year": 2017 }, { "abstract": "As shown by thermodynamic modeling, accumulation of fission products in the course of irradiation of mixed uranium plutonium nitride containing 0.25 wt C impurity leads to the formation of a multicomponent carbonitride solid solution containing U, Pu, Am, Np, Zr, Y, lanthanides, and also separate carbide (UMoC2, U2RuC2, URu3C0,7, BaC2, SrC2) and nitride (U2N3) phases and intermetallic compounds U(Ru, Rh, Pd)3. The b decay of metallic radionuclides in separate carbide phases of spent nuclear fuel leads to changes in their chemical compositions. The transformation kinetics of separate dicarbide (89SrC2 89YC2, 90SrC2 90YC2 90ZrC C, 140BaC2 140LaC2 140CeC2) and complex carbide (U99MoC2 UC2 99Tc) phases was calculated.", "author_names": [ "G S Bulatov", "K N Gedgovd", "A G Maslennikov", "D Yu Lyubimov" ], "corpus_id": 99282287, "doc_id": "99282287", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Effect of carbon impurity in irradiated mixed uranium plutonium nitride on the phase composition upon b decay of fission products", "venue": "Radiochemistry", "year": 2017 }, { "abstract": "Manganese ferrite/porous graphite carbon nitride composites (MnFe2O4/porous g C3N4[PCN] were synthesized by template assisted thermal polymerization and hydrothermal method and applied for high adsorption of U(VI) from aqueous solution. Results indicated that the maximum adsorption capacity of MnFe2O4/PCN (MPCN) was 367.9 mg g 1 under optimum conditions (pH 5, t 15 min, and T 308 K) which was higher than that of g C3N4 (185.1 mg g 1) Adsorption was well fitted with Langmuir isotherm model and pseudo second order kinetic equation. Thermodynamic analysis showed that adsorption is an endothermic, spontaneous process. X ray photoelectron spectra revealed that amino and metal oxygen groups are involved in the complexing adsorption of uranium. Adsorption efficiency remained 92.5% after five adsorption desorption cycles. The results of this paper indicated that MnFe2O4/PCN composites can be efficiently used as an ideal material for U(VI) adsorption.", "author_names": [ "Yujie Ge", "Zhiqiang Alex He", "Jiao Wu", "Guohua Wang", "Shui-bo Xie", "Jinxiang Liu" ], "corpus_id": 220721950, "doc_id": "220721950", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Manganese ferrite/porous graphite carbon nitride composites for U(VI) adsorption from aqueous solutions", "venue": "Journal of Radioanalytical and Nuclear Chemistry", "year": 2020 } ]
P-type silicon ZnO
[ { "abstract": "Hydrothermal method was successfully utilized to grow ZnO nanorods on p type silicon substrate. The highly dense grown ZnO nanorods are well aligned, and perpendicularly to substrate confirmed by scanning electron microscopy. The X ray diffraction analysis confirmed that the [002] orientation was the major growth direction of the ZnO nanorods. A shadow masks have used to fabricate Metal semiconductor metal (MSM) structure. Three arrays of Ag interdigitated electrodes were then deposited onto the ZnO nanorod/Si substrates. The current characteristics of [Ag/ZnO nanorod/Ag]/Si devices were investigated range of 2 to +2 V. The as fabricated devices showed a contrast ratio (i.e. the photocurrent/dark current) of 1.17 along with room temperature 0.115 mA/W responsivity at 365 nm and 2 V. A simulation analysis for the theoretical MSM structure has also been done in this work. A Visual TCAD was also used to simulate this device. A comparative study of experimentally and theoretically obtained results was also carried out and both results were found in good agreement of each other.", "author_names": [ "M Kumar", "Shibu Singh", "Pramod Kumar Tiwari", "S H Park" ], "corpus_id": 221667935, "doc_id": "221667935", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "SIMULATION AND FABRICATION OF Ag/ZnO NANORODS/Ag ULTRAVIOLET DETECTORS ON p TYPE SILICON", "venue": "", "year": 2020 }, { "abstract": "The results of the synthesis and characterization of self assembled ZnO nanoparticles (NP) embedded within a SiO2 matrix deposited on (111) p type silicon by reactive radio frequency sputtering are reported. Synthesis consists in a sequential deposit of SiO2/metallic Zn/SiO2/SiO2 layers, using argon and oxygen as the working atmosphere at a substrate temperature of 400degC. ZnO NP were nucleated at valleys of the first rough SiO2 layer by the action of the reactive atmosphere and Zn atoms coming from the sputtered target. Three different deposition times for the zinc interlayer were studied. Scanning electron microscopy shows that films have uniform topography and transmission electron microscopy indicates the presence of NP with sizes around 10 nm. The successful production of ZnO is corroborated by x ray photoemission spectroscopy studies. Secondary ion mass spectroscopy shows a spatial distribution of zinc depending on the thickness of the zinc interlayer, ZnO NP follow a similar distribution. Electrical transport studies have shown the formation of a rectifying structure between the layer and silicon substrate. Spectral response is observed with a wavelength distribution depending on the zinc interlayer thickness and probably due to the formation of ZnO NP of different sizes.", "author_names": [ "Mario Avila-Meza", "O Zelaya-Angel", "Salvador Gallardo", "Jose Luis Fernandez-Munoz", "D R Alfaro-Flores", "Miguel Angel Melendez-Lira" ], "corpus_id": 104741930, "doc_id": "104741930", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Synthesis and Characterization of Self Assembled ZnO Nanoparticles Embedded Within a SiO2 Matrix Deposited on (111) p Type Silicon By Reactive RF Sputtering Using Metallic Zinc Target As Precursor", "venue": "Journal of Electronic Materials", "year": 2018 }, { "abstract": "Abstract In this work we discuss a method of preparation of a highly sensitive light detector based on ZnO nanorods. A photoresistor constructed by us is based on a heterojunction between high quality ZnO nanorods and high resistivity p type Si used as a substrate for nanorods' deposition. ZnO nanorods are grown by a modified version of a microwave assisted hydrothermal method which allows for growth of high quality ZnO nanorods in a few minutes. The obtained photoresistor responds to a wide spectral range of light starting from near infrared (IR) to ultraviolet (UV) Properties of the detector are evaluated. We propose the use of the detector as an optical switch.", "author_names": [ "Bartlomiej S Witkowski", "Rafal Pietruszka", "Sylwia Gieraltowska", "L Wachnicki", "Hanka Przybylinska", "Marek Godlewski" ], "corpus_id": 126376092, "doc_id": "126376092", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Photoresistor based on ZnO nanorods grown on a p type silicon substrate", "venue": "", "year": 2017 }, { "abstract": "Al ZnO/(n)Si and Al ZnO/(p)Si heterojunction structures were fabricated by RF sputtering of Al ZnO thin film on Si substrates and their electrical and photoresponse properties were comparatively analyzed. The Al ZnO/(n)Si heterojunction exhibited excellent diode behavior with an equivalent barrier height of 0.72 eV and an rectification ratio of <inline formula> <tex math notation=\"LaTeX\"$6.7 \\times 10^{3} /tex math>/inline formula> at 0.5 V, while no rectifying behavior was observed for Al ZnO/(p)Si device. Illuminated I V analysis performed with different light intensities revealed excellent photoresponse properties and the strong dependence of the photocurrent on external bias for both Al ZnO/(n)Si and Al ZnO/(p)Si structures. The Al ZnO/(n)Si structure requires smaller reverse bias than Al ZnO/(p)Si for similar photoresponse. Based on dark I V, illuminated I V, and the energy band diagrams, photoresponse mechanisms were explained. In order to further understand the photoresponse mechanisms, quantum efficiency measurements were carried out, with applied external voltage bias. A general descriptive model was presented for the first time for the photogenerated current density in both Al ZnO/(n)Si and Al ZnO/(p)Si heterojunctions at different voltage bias.", "author_names": [ "Zhen Gao", "Navid M S Jahed", "Siva Sivoththaman" ], "corpus_id": 46477610, "doc_id": "46477610", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Biased Photoresponse Analysis of Al ZnO Heterojunctions with n and p Type Silicon", "venue": "IEEE Transactions on Electron Devices", "year": 2017 }, { "abstract": "Sol gel spin coating deposition method was used to deposits nanostructured ZnO on P type silicon. Zinc acetate, diethanolamine, and isopropyl were used as starting material, stabiliser and solvent respectively. Surface morphology was studied by field emission scanning electron microscopy (FESEM) It was found that nanostructured ZnO was distributed uniformly over the P type Silicon substrate. This was supported by atomic force microscopy (AFM) image which shows the all the surfaces are covered by nanoparticle of ZnO. X ray diffraction (XRD) was employed to analyse the structural and crystalline of nanostructured ZnO. Three peak (100) (002) and (101) correspond to nanostructed ZnO are appear. Temperature dependence I V characteristic was investigated in range of 25 K to 300 K by using close cycle cryostat and using helium as cooler agent. It is found that the resistance were decrease toward the higher temperature. The result shows that resistivity gradually decreased due to increases of temperature.", "author_names": [ "Kevin Alvin Eswar", "F S Husairi", "S A Mohammad", "Aziz Azlinda", "Mohamad Rusop", "Syahrul Afzal Che Abdullah" ], "corpus_id": 99297068, "doc_id": "99297068", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Synthesis of spin coated nanostructured ZnO on P type silicon and Temperature dependence of I V characteristic", "venue": "", "year": 2015 }, { "abstract": "Abstract ZnO nanostructures have been synthesized on p type silicon substrates using a two step, spontaneous oxidation of Zn films method at room temperature. The samples both with and without a thin layer of gold in different positions have been spontaneously oxidized in a humid atmosphere for seven days to form nanosheets and ball cactus like nanostructures. Diverse morphologies of hierarchical ZnO nanostructures have been obtained by annealing the samples at 700 degC in a nitrogen atmosphere for 1 h. A growth mechanism has been proposed for the formation of different ZnO nanostructures. It was found that the band gap emission can be greatly improved and that the defect emission is suppressed to a noise level when a thin layer of Au was deposited between the Zn and the Si substrate. Moreover, our results show that the ZnO/p Si heterojunction exhibits good performance for visible spectrum detection.", "author_names": [ "Q Xu", "Qijin Cheng", "Zifeng Zhang", "Rongdun Hong", "Xiaping Chen", "Zhengyun Wu", "Fengyan Vancouver Zhang" ], "corpus_id": 98139721, "doc_id": "98139721", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Synthesis of ZnO nanostructures by spontaneous oxidation of Zn films on p type silicon substrates", "venue": "", "year": 2014 }, { "abstract": "Abstract In this paper, the growth of n type aluminum boron co doped ZnO (n AZB) on a p type silicon (p Si) substrate by sol gel method using spin coating technique is reported. The n AZB/p Si heterojunctions were annealed at different temperatures ranging from 400 to 800 degC. The crystallite size of the AZB nanostructures was found to vary from 28 to 38 nm with the variation in annealing temperature. The band gap of the AZB decreased from 3.29 to 3.27 eV, with increasing annealing temperature from 400 to 700 degC and increased to 3.30 eV at 800 degC probably due to the formation of Zn 2 SiO 4 at the interface. The band gap variation is explained in terms of annealing induced stress in the AZB. The n AZB/p Si heterojunction exhibited diode behavior. The best rectifying behavior was exhibited at 700 degC.", "author_names": [ "Vinod Kumar", "Neetu Singh", "Avinashi Kapoor", "Odireleng Martin Ntwaeaborwa", "Hendrik C Swart" ], "corpus_id": 96696872, "doc_id": "96696872", "n_citations": 29, "n_key_citations": 0, "score": 0, "title": "Fabrication and characterization of n type aluminum boron co doped ZnO on p type silicon (n AZB/p Si) heterojunction diodes", "venue": "", "year": 2013 }, { "abstract": "Compared to the p n junction type device (Device A) with an n type ZnO nanowire (n ZnO)/p type silicon (p Si) hybrid structure, the newly designed device (Device B) with an n ZnO/reduced graphene oxide sheet (rGO)/p Si hybrid structure displays interesting electrical characteristics such as lower turn on voltage and better current symmetry. The addition of rGO between n ZnO and the p Si substrate enables tuning of the p n junctions into back to back Schottky junctions and lowering of the turn on voltages, implying great potential applications in electronic and optoelectronic devices. The electrical characteristics and operating mechanism of these two devices are fully discussed.", "author_names": [ "Zhiwen Liang", "Xiang Cai", "Shaozao Tan", "Peihua Yang", "Long Zhang", "Xiang Yu", "Keqiu Chen", "Hanming Zhu", "Pengyi Liu", "Wenjie Mai" ], "corpus_id": 5170551, "doc_id": "5170551", "n_citations": 19, "n_key_citations": 0, "score": 0, "title": "Fabrication of n type ZnO nanowire/graphene/p type silicon hybrid structures and electrical properties of heterojunctions.", "venue": "Physical chemistry chemical physics PCCP", "year": 2012 }, { "abstract": "P type silicon was used as a substrate of deposition of nanostructured ZnO by sol gel spin coating technique, while zinc acetate, diethanolamine, and isopropyl were used as starting material, stabilizer and solvent respectively. Surface morphology was studied by Field Emission Scanning Electron Microscopy (FESEM) It was found that nanostructured ZnO was distributed uniformly over the P type Silicon substrate. This was supported by atomic force microscopy (AFM) image which shows the all the surfaces are covered by nanoparticle of ZnO. X ray diffraction (XRD) was employed to analyse the structural and crystalline of nanostructured ZnO. Three peak (100) (002) and (101) correspond to nanostructed ZnO are appear. Temperature dependence I V characteristic was investigated in range of 25 K to 300 K by using Close Cycle Cryostat and using Helium as cooler agent. It is found that the resistance were decrease toward the higher temperature. The result shows that resistivity gradually decreased due to increases of temperature.", "author_names": [ "Kevin Alvin Eswar", "F S Husairi", "Sharifah Aminah Syed Mohamad", "Aziz Azlinda", "Mohamad Rusop", "Syahrul Afzal Che Abdullah" ], "corpus_id": 98383892, "doc_id": "98383892", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Synthesis and Temperature Dependence of I V Characteristic of Spin Coated Nanostructured ZnO on P Type Silicon", "venue": "", "year": 2013 }, { "abstract": "An inorganic nano light emitting transistor (INLET) consisting of p type porous Si nanowires (PoSiNWs) and an n type ZnO nanofilm was integrated on a heavily doped p type Si substrate with a thermally grown SiO2 layer. To verify that modulation of the Fermi level of the PoSiNWs is key for switchable light emitting, I V and electroluminescent characteristics of the INLET are investigated as a function of gate bias (V g As the V g is changed from 0 V to 20 V, the current level and light emission intensity in the orange red range increase by three and two times, respectively, with a forward bias of 20 V in the p n junction, compared to those at a V g of 0 V. On the other hand, as the V g approaches 10 V, the current level decreases and the emission intensity is reduced and then finally switched off. This result arises from the modulation of the Fermi level of the PoSiNWs and the built in potential at the p n junction by the applied gate electric field.", "author_names": [ "Sang Hoon Lee", "Jong Woo Kim", "Tae Il Lee", "Jae Min Myoung" ], "corpus_id": 21958602, "doc_id": "21958602", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Inorganic Nano Light Emitting Transistor: p Type Porous Silicon Nanowire/n Type ZnO Nanofilm.", "venue": "Small", "year": 2016 } ]
DBR laser perovskite
[ { "abstract": "Single mode ridge waveguide semiconductor lasers based on AlGaAs/GaAs/InGaAs heterostructure with a surface distributed Bragg reflector were developed. Calculation of reflection spectrum based on coupled mode theory was carried out. Waveguide ridge with width of 5 mkm and Bragg grating with a period of 2 mkm was formed in the upper cladding layer by contact photolithography. Experimental studies shown that spectrum width did not exceed 0.3 nm both at continuous wave and pulse of 100 ns pump. Temperature stability of emission wavelength increased up to 0.075 nm/C.", "author_names": [ "Vasilii V Zolotarev", "A V Rozhkov", "A Yu Leshko", "Sergey O Slipchenko", "Nikita A Pikhtin", "P S Kopev" ], "corpus_id": 229307573, "doc_id": "229307573", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Single mode narrow spectrum DBR laser (1040nm)", "venue": "2020 International Conference Laser Optics (ICLO)", "year": 2020 }, { "abstract": "In this paper we present various configurations of erbium DBR lasers based on seven core fiber. By using femtosecond writing technique, it is possible to fabricate fiber Bragg gratings (FBGs) in selected cores of multicore fibers (MCF) at a certain transverse and longitudinal locations in a fiber, thus allowing for fabrication of advanced reflecting elements. Different schemes of tunable lasers are presented based on both uniform and chirped FBGs.", "author_names": [ "Alexandr V Dostovalov", "Alexey A Wolf", "Mikhail I Skvortsov", "Kseniya V Proskurina", "Sergey A Babin" ], "corpus_id": 229307638, "doc_id": "229307638", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Wavelength tunable DBR fiber laser based on multicore fiber", "venue": "2020 International Conference Laser Optics (ICLO)", "year": 2020 }, { "abstract": "Abstract Organic inorganic hybrid perovskite semiconductors as gain materials have been widely investigated in various lasing structures. Here, we construct a vertical cavity surface emitting deep blue laser device in one step. A high quality CH3NH3PbCl3 single crystalline film as gain material is in situ grown in solution confined between a pair of distributed Bragg reflectors, which naturally form an optical microcavity. The thickness of the perovskite film can be easily adjusted from submicron to several microns by changing the applied pressure on the substrates. At room temperature, the resulting device can lase in a range of 414 435 nm when pumped by an 8 ns pulsed semiconductor laser diode, exhibiting a typical threshold of 211 mJ/cm2. The lasing wavelength and the number of modes are tunable due to the adjustable thickness of the perovskite film.", "author_names": [ "Cheng Tian", "Shiqi Zhao", "Tong Guo", "Wanjin Xu", "Yanping Li", "Guangzhao Ran" ], "corpus_id": 225318090, "doc_id": "225318090", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Deep blue DBR laser at room temperature from single crystalline perovskite thin film", "venue": "", "year": 2020 }, { "abstract": "Lead halide perovskites have emerged as excellent optical gain materials for low cost and flexible lasers. Recently, continuous wave (CW) optically driven lasing was established in perovskite crystals; however, the mechanism of low threshold operation is still disputed. In this study, CW pumped lasing from one dimensional CsPbBr3 nanoribbons (NBs) with a threshold of ~130 W cm 2 is demonstrated, which can be ascribed to the large refractive index induced by the exciton polariton (EP) effect. Increasing the temperature reduces the exciton fraction of EPs, which decreases the group and phase refractive indices and inhibits lasing above 100 K. Thermal management, including reducing the NB height to ~120 60 nm and adopting a high thermal conductivity sink, e.g. sapphire, is critical for CW driven lasing, even at cryogenic temperatures. These results reveal the nature of ultralow threshold lasing with CsPbBr3 and provide insights into the construction of room temperature CW and electrically driven perovskite macro/micro lasers.", "author_names": [ "Qiuyu Shang", "Meili Li", "Liyun Zhao", "Dingwei Chen", "Shuai Zhang", "Shulin Chen", "Peng Gao", "Chao Shen", "Jun Xing", "Guichuan Xing", "Bo Shen", "Xinfeng Liu", "Qing Zhang" ], "corpus_id": 221121812, "doc_id": "221121812", "n_citations": 25, "n_key_citations": 0, "score": 1, "title": "Role of the Exciton Polariton in a Continuous Wave Optically Pumped CsPbBr3 Perovskite Laser.", "venue": "Nano letters", "year": 2020 }, { "abstract": "We fabricated a Yb doped yttrium aluminium garnet (Yb:YAG) crystal derived silica fiber (YCDSF) using an assembly consisting of a YAG crystal rod and silica tube on a CO2 laser heated drawing tower. The fiber has a Yb concentration of 5.66 wt% and absorption coefficient of 32 dB/cm at 980 nm. The figure of merit of the unsaturated absorption and gain per unit length of the YCDSF are 93% and 4.4 dB/cm, respectively. Based on the results of the numerical simulation, an all fiber distributed Bragg reflector (DBR) laser using only a 1.5 cm long YCDSF is experimentally demonstrated to have a maximum output power of 360 mW with a pump threshold power of 21 mW. The fiber laser also achieved an optical signal to noise ratio of 80 dB, a beam quality factor of 1.022 in two orthogonal directions and a slope efficiency of up to 50.5% These results indicate that the all fiber DBR laser has potential applications in high quality seed sources and coherent optical communications.", "author_names": [ "Ying Wan", "Jianxiang Wen", "Yanhua Dong", "Chen Jiang", "Ming Jia", "Fengzai Tang", "Na Chen", "Ziwen Zhao", "Sujuan Huang", "Fufei Pang", "Tingyun Wang" ], "corpus_id": 220978321, "doc_id": "220978321", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Exceeding 50% slope efficiency DBR fiber laser based on a Yb doped crystal derived silica fiber with high gain per unit length.", "venue": "Optics express", "year": 2020 }, { "abstract": "We demonstrate a low concentrated solar pumped laser (SPL) with natural sunlight by using an all inorganic cesium lead halide perovskite (CsPbBrxI3 x) nanocrystal (NC) dispersed in toluene as a sensitizer. The perovskite NCs exhibit substantial advantages for SPL applications because of their broad absorption and narrow photoluminescence (PL) spectra with high quantum yield using inexpensive commercial precursors. We successfully synthesized CsPbBrxI3 x NCs with precisely tuned PL wavelengths from 581 to 612 nm by altering the I/Br ratio to achieve spectral overlap with Nd3+ ions, which have been widely used as a laser medium for SPLs. The measurement results show that the laser output power is highly sensitive to the peak PL wavelength of the NCs, and the highest laser output was obtained at the peak wavelength of 595 nm. Although the synthesized NCs have a wider absorption band, the laser output power obtained was much less than that of an organic dye of rhodamine 6G (R6G) The numerical analyses show that the optimal peak PL wavelength is 10 nm shorter than the absorption peak of Nd3+ ions because of the reflection property of the dichroic mirror coated on the input window. Moreover, we found that the concentration of NCs needs to be optimized in response to the peak PL wavelength. The calculations show that a laser output power 2.7 times greater than that of R6G can be obtained under an optimal peak PL wavelength of 575 nm and a concentration of 24 g/l for the CsPbBrxI3 x NCs.", "author_names": [ "Taizo Masuda", "Yaohong Zhang", "Chao Ding", "Feng Liu", "Kiyoto Sasaki", "Qing Shen", "Masamori Endo" ], "corpus_id": 225661792, "doc_id": "225661792", "n_citations": 4, "n_key_citations": 0, "score": 1, "title": "All inorganic cesium lead halide perovskite nanocrystals for solar pumped laser application", "venue": "", "year": 2020 }, { "abstract": "In this paper, we present DBR lasers using DUV lithography in a generic InP based photonic integration platform. The DBR lasers exhibit SMSR over 45 dB and laser linewidths below 100 kHz.", "author_names": [ "Mu-Chieh Lo" ], "corpus_id": 230679688, "doc_id": "230679688", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Narrow Linewidth DBR Laser Using Open Access High Precision Grating in InP PIC Generic Foundry Platform", "venue": "", "year": 2020 }, { "abstract": "Abstract Flexible energy harvesters based on piezoelectric nanomaterials have attracted great attention because they enable a self powered system that converts electric energy from ambient energy resources. To achieve perovskite structured piezoelectric nanopowders, most studies have utilized multi step chemical based hydrothermal reaction with repeat purification processes, which results in time consuming production, low yield production, and the inevitable existence of second phase. As an alternative that addresses the drawbacks of previous synthesis methods, the ultrafast laser processing based on cold ablation is highly promising for nanomaterial synthesis. In this work, we investigated the feasibility of synthesizing BaTiO3 nanoparticles by the picosecond laser ablation of a bulk BaTiO3 target in an ethanol solvent. The picosecond laser synthesized BaTiO3 nanoparticles have a spherical shape with a size of ~300 nm and typical perovskite crystallinity with tetragonal phase. To investigate the piezoelectric response from BaTiO3 nanoparticles, we used a piezoresponse force microscope and confirmed the piezoelectric charge constant of ~130 pmV 1. The results indicate the viability of synthesizing piezoelectric ceramic nanoparticles by the laser ablation of a bulk target in a liquid environment.", "author_names": [ "Insung S Choi", "Su-jin Lee", "Jong Chan Kim", "Yeong-gyu Kim", "Dong Yeol Hyeon", "Kung Sun Hong", "Jeong Hun Suh", "Dongsig Shin", "Hu Young Jeong", "Kwi-Il Park" ], "corpus_id": 213654982, "doc_id": "213654982", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Piezoelectricity of picosecond laser synthesized perovskite BaTiO3 nanoparticles", "venue": "", "year": 2020 }, { "abstract": "Perovskite solar cells have attracted much attention recently for their high efficiency, ease of preparation and low cost. Here, we report a novel laser annealing method for perovskite films at a low substrate temperature by scanning laser spots on the film surfaces. An ultrafast crystallization process within a few seconds is realized under a laser with a high intensity and a fast scanning speed. Because the crystalline perovskite phase has a stronger light absorption than the amorphous phase, the fast laser annealing can induce a higher temperature in the former and lead to the selective growth of large perovskite grains. Under optimum conditions, perovskite films with high crystallinity are successfully fabricated, resulting in perovskite solar cells with high power conversion efficiency and good stability. Moreover, a faster laser annealing process of perovskite films is achieved by using a linear laser beam, which is expected to be a promising technique for the mass production of large scale perovskite solar cells.", "author_names": [ "Peng You", "Guijun Li", "Guanqi Tang", "Jiupeng Cao", "Feng Yan" ], "corpus_id": 213739578, "doc_id": "213739578", "n_citations": 49, "n_key_citations": 0, "score": 0, "title": "Ultrafast laser annealing of perovskite films for efficient perovskite solar cells", "venue": "", "year": 2020 }, { "abstract": "We report on a facile and rapid photo induced process to conjugate graphene based materials with metal halide perovskite nanocrystals. We show that a small number of laser pulses is sufficient to decorate the 2 dimensional (2D) flakes with metal halide nanocrystals without affecting their primary morphology. At the same time, the density of anchored nanocrystals could be finely tuned by the number of irradiation pulses. This facile and rapid room temperature method provides unique opportunities for the design and development of perovskite 2D nanoconjugates, exhibiting synergetic functionality by combining nanocrystals of different morphologies and chemical phases with various 2D materials.", "author_names": [ "Athanasia Kostopoulou", "Konstantinos Brintakis", "Efthymis Serpetzoglou", "Emmanuel Stratakis" ], "corpus_id": 215793670, "doc_id": "215793670", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Laser Assisted Fabrication for Metal Halide Perovskite 2D Nanoconjugates: Control on the Nanocrystal Density and Morphology", "venue": "Nanomaterials", "year": 2020 } ]
Resistivity Measurements on Germanium for Transistors
[ { "abstract": "This paper discusses a laboratory method which has been found very useful for measuring the resistivity of the semiconductor germanium. The method consists of placing four probes that make contact along a line on the surface of the material. Current is passed through the outer pair of probes and the floating potential is measured across the inner pair. There are seven cases considered, the probes on a semi infinite volume of semiconductor material and the probes near six different types of boundaries. Formulas and curves needed to compute resistivity are given for each case.", "author_names": [ "L B Valdes" ], "corpus_id": 51660826, "doc_id": "51660826", "n_citations": 557, "n_key_citations": 8, "score": 1, "title": "Resistivity Measurements on Germanium for Transistors", "venue": "Proceedings of the IRE", "year": 1954 }, { "abstract": "This paper discusses a laboratory method which has been found very useful for measuring the resistivity of the semiconductor germanium. The method consists of placing four probes that make contact along a line on the surface of the material. Current is passed through the outer pair of probes and the floating potential is measured across the inner pair. There are seven cases considered, the probes on a semi infinite volume of semiconductor mate1ial and the probes near six different types of boundaries. Formulas and curves needed to compute resistivity are given for each case.", "author_names": [ "L B VALDESt" ], "corpus_id": 135463668, "doc_id": "135463668", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Resistivity Measurements on Germanium for Transistors*", "venue": "", "year": 2006 }, { "abstract": "A three terminal dc measurement is made of avalanche multiplication of holes injected from the emitter into the collector junction of diffused base germanium p n p transistors. The method is applicable to asymmetric thin base transistors at currents at which dc base current is independent of base width when emitter to base voltage (V EB is held constant. Injected collector current and V EB are measured at constant emitter current as a function of collector to base voltage (V) V EB is measured to take base narrowing into account. Collector reverse current is balanced out. The advantages of this method over two terminal measurements are that surface, space charge recombination and internal field emission currents are balanced out and no a priori assumption of the form of the multiplication factor M(V) is needed. For collector barriers which are nearly step n^}p junctions with the p type resistivity in the neighborhood of 1 ohm cm, the multiplication data, which cover the range 1.05 \\siml M \\siml 2.0 fit the Miller equation M^ 1} 1 (V/V_{B}{n} n 3.2 \\pm 0.2 in agreement with Miller's two terminal measurements using alloy and grown junction Ge transistors. The parameters V B from extrapolation of the present data agree within experimental error of five per cent with the collector diode breakdowns BV CBO measured by Miller. However, in the present measurements on diffused base transistors, appreciable surface current multiplication occurs with the result that BV CBO measured at 1 ma is approximately 18 per cent less than V B The absence of microplasma noise in the multiplied injected hole current indicates that multiplication occurs uniformly in the collector barrier under the emitter at least to M 2", "author_names": [ "Alan B Kuper" ], "corpus_id": 95845940, "doc_id": "95845940", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Measurement of avalanche multiplication of injected holds in germanium p n p diffused base transistors", "venue": "", "year": 1964 }, { "abstract": "This quarterly progress report, thirteenth of a series, describes NBS activities directed toward the development of methods of measurement for semiconductor materials, process control, and devices. Significant accomplishments during this reporting period include the disclosure of substantial differences in measurements of transistor delay time, a device characteristic frequently used as a screen in radiation hardness assurance tests, as measured with two different instruments; successful application of the infrared response technique to the study of radiation damaged, lithium drifted silicon detectors; and identification of a condition that minimizes wire flexure and reduces the failure rate of wire bonds in transistors and integrated circuits under slow thermal cycling conditions. Work is continuing on measurement of resistivity of semiconductor crystals; study of gold doped silicon; specification of germanium for gamma ray detectors; evaluation of wire bonds and die attachment; measurement of thermal properties of semiconductor devices, delay time and related carrier transport properties in junction devices, and noise properties of microwave diodes; and characterization of silicon nuclear radiation detectors. Supplementary data concerning staff, standards committee activities, technical services, and publications are included as appendixes.", "author_names": [ "W Murray Bullis" ], "corpus_id": 139878228, "doc_id": "139878228", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Methods of Measurement for Semiconductor Materials, Process Control, and Devices: Quarterly Report, July 1 to September 30, 1969", "venue": "", "year": 2017 }, { "abstract": "Single crystalline germanium nanowires were synthesized via vapor liquid solid mechanism. The characteristics of the Ge nanowires were investigated by a transmission electron microscope to identify the [111] growth direction. The Ge nanowire based field effect transistors on Si3N4 dielectrics were fabricated, showing a p type semiconducting behavior with hole mobility of 47.03 cm2 V 1 s 1. The formation of Cu3Ge/Ge/Cu3Ge nanoheterostructures was demonstrated with the reaction between copper contacts and Ge nanowires by rapid thermal annealing. The diameter dependent electrical transport property of Ge nanowires indicates that with diameters of more than 80 nm, the resistivity of Ge nanowires decreased with diameter decrease, while with diameters of less than 80 nm, it increased. With multiple annealing processes, the channel length of the Ge nanowire transistors can be successfully controlled. From electrical measurements of each annealing step, the electrical transport property was significantly improved by sequential formation of Cu3Ge contacts. The gradual formation of the germanide structure reduces Fermi level pinning effect and increases the Ohmic behavior of electrical transportation.", "author_names": [ "Shan-Chun Hsu", "Cheng-Lun Hsin", "Chun-Wei Huang", "Shih-Ying Yu", "Chun Wen Wang", "Chi-Ming Lu", "Kuo-Chang Lu", "Wen-Wei Wu" ], "corpus_id": 59401547, "doc_id": "59401547", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Single crystalline Ge nanowires and Cu3Ge/Ge nano heterostructures", "venue": "", "year": 2012 }, { "abstract": "The problematics of contacts optimization on germanium metal oxide semiconductor field effect transistors suffers from a gap between fundamental studies and the structures obtained after full processing. The contact properties of metals on Ge were so far mostly investigated on weakly n doped samples under the pure thermionic emission regime. These experimental conditions are suitable for an accurate extraction; the measured Schottky barrier height (SBH) being usually large and linked to the interfacial current density by a relatively simple Arrhenius relationship. However, a device oriented approach would consist in meeting the contact resistivity requirements in the ohmic regime for metallic contacts on a highly doped semiconductor (e.g. doped source and drain) through the choice of metal, interface preparation, and doping conditions. We hereby detail SBH extractions based on contact resistance (R co measurements on highly n and p doped Ge, where the predominant tunnel current component results in ohmic behavior. We applied this methodology to our fully processed germanium on insulator (GeOI) samples with Ti based contacts, yielding effective barriers of 0.32 eV for electrons and 0.15 eV for holes. The method provides a good physical understanding of the technological factors impacting the electrical properties, enabling to define paths toward ohmic contact optimization in the context of device integration on GeOI.", "author_names": [ "Louis Hutin", "Cyrille Le Royer", "Claude Tabone", "V Delaye", "F Nemouchi", "F Aussenac", "Laurent Clavelier", "Maud Vinet" ], "corpus_id": 97596798, "doc_id": "97596798", "n_citations": 23, "n_key_citations": 0, "score": 0, "title": "Schottky Barrier Height Extraction in Ohmic Regime: Contacts on Fully Processed GeOI Substrates", "venue": "", "year": 2009 }, { "abstract": "This paper presents a comprehensive study of the effects of heavy doping and germanium in the base on the dc performance of Si/Si/sub 1 x/Ge/sub x//Si npn Heterojunction Bipolar Transistors (HBTs) The lateral drift mobility of holes in heavily doped epitaxial SiGe bases affects the base sheet resistance while the effective bandgap is crucial for the vertical minority carrier transport. The devices used in this study were Si/sub 1 x/Ge/sub x/ npn HBTs with flat Ge and B profiles in the base grown by Rapid Thermal Chemical Vapor Deposition (RTCVD) Hall and drift lateral hole mobilities were measured in a wide range of dopings and Ge concentrations. The drift mobility was indirectly measured based on measured sheet resistivity and SIMS measurements, and no clear Ge dependence was found. The Hall scattering factor is less than unity and decreases with increasing Ge concentration. The effective bandgap narrowing, including doping and Ge effects, was extracted from the room temperature collector current measurements over a wide range of Ge and heavy doping for the first time. We have observed bandgap narrowing due to heavy base doping which is, to first order, independent of Ge concentration, but less than that observed in silicon, due to the effect of a lower density of states. A model for the collector current enhancement with respect to Si devices versus base sheet resistance is presented.", "author_names": [ "Z Matutinovic-Krstelj", "Vivek Venkataraman", "Erwin J Prinz", "James C Sturm", "Charles W Magee" ], "corpus_id": 109167078, "doc_id": "109167078", "n_citations": 48, "n_key_citations": 0, "score": 0, "title": "Base resistance and effective bandgap reduction in n p n Si/Si/sub 1 x/Ge/sub x//Si HBTs with heavy base doping", "venue": "", "year": 1996 }, { "abstract": "This paper presents a comprehensive study of the effects of heavy doping and germanium in the base on the dc performance of Si/Sil 2 Ge,/Si npn Heterojunction Bipolar Transistors (HBT's) The lateral drift mobility of holes in heavily doped epitaxial SiGe bases affects the base sheet resistance while the effective bandgap is crucial for the vertical minority carrier transport. The devices used in this study were Sil ,Ge, npn HBT's with flat Ge and B profiles in the base grown by Rapid Thermal Chemical Vapor Deposition (RTCVD) Hall and drift lateral hole mobilities were measured in a wide range of dopings and Ge concentrations. The drift mobility was indirectly measured based on measured sheet resistivity and SIMS measurements, and no clear Ge dependence was found. The Hall scattering factor is less than unity and decreases with increasing Ge concentration. The effective bandgap narrowing, including doping and Ge effects, was extracted from the room temperature collector current measurements over a wide range of Ge and heavy doping for the first time. We have observed bandgap narrowing due to heavy base doping which is, to first order, independent of Ge concentration, but less than that ob served in silicon, due to the effect of a lower density of states. A model for the collector current enhancement with respect to Si devices versus base sheet resistance is presented.", "author_names": [ "Vivek Venkataraman", "Erwin J Prinz", "James C Sturm", "Charles W Magee" ], "corpus_id": 114550903, "doc_id": "114550903", "n_citations": 11, "n_key_citations": 1, "score": 0, "title": "Base Resistance and Effective Bandgap Reduction in n p n Si/Sil ,Ge,/Si HBT's with Heavy Base Doping", "venue": "", "year": 1996 }, { "abstract": "Abstract An investigation was made for developing a process for depositing device quality silicon and/or germanium films on glazed polycrystalline insulating substrates by vacuum evaporation of silicon and/or germanium and to form thin film diodes and transistors in these films. The silicon depositions were carried out for the control of n type doping, Hall measurements, improvement of crystallinity by annealing and by electron beam heating, and fabrication of improved diodes and transistors. Diodes with ohmic contacts were made with reverse breakdowns of 15 to 60 volts. The apparatus for Hall and resistivity measurements was improved, resulting in reliable and reproducible data on mobilities and carrier concentrations. The patterns for the Hall resistivity silicon deposition mask and the photoresist mask were changed so that both resistivity and Hall measurements could be made in a single operation. Improved crystalline quality in silicon thin films has been obtained through high temperature annealing. Initial vacuum deposited films exhibited increased grain size and Laue spots. (Author)", "author_names": [ "Egons Rasmanis", "James P Cline" ], "corpus_id": 109171887, "doc_id": "109171887", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "ACTIVE THIN FILM TECHNIQUES MICROMIN PROGRAM.", "venue": "", "year": 1963 }, { "abstract": "Germanium(Ge) has attractive properties such as high carrier mobility, compatibility with high K dielectrics, and lattice matched for GaAs growth. Germanium on insulator (GOI) (1) offers the advantages of germanium and combines them with those of silicon on insulator (SOI) Bonding to substrates which are thermally matched to Ge eases process temperature constraints and can have additional benefits depending on the substrate used. Transistors have previously been reported on a germanium on sapphire wafer bonded platform (2) Fine grain alumina offers a cheaper alternative to sapphire while still retaining advantages such as low substrate losses and better crosstalk suppression. In this work Circular Geometry MOS transistors fabricated and tested on germanium bonded to a fine grain alumina substrate (superstrate 997) are presented. The Ge on Alumina substrate was realised by bonding a polysilicon coated and subsequently planarised alumina substrate to a Umicore 2.7 2.9 ohmcm n Ge substrate(3) After subsequent bond strength annealing at 150 C the Ge was thinned by precision in house grinding and diamond particulate polishing leaving a thick 100mm Ge on Alumina layer. The ground and polished substrate is shown in figure 1. Circular geometry transistors were fabricated using a low temperature self aligned W gate fabrication process. The maximum temperature seen by the transistors was 450 C. The transistors having a W/L of 9 also employed a 20nm APCVD silicon dioxide layer as the gate dielectric. As a direct comparison identical transistors where fabricated on bulk Ge substrates with the same resistivity as the bonded structure. Figure 2 shows the resultant output characteristics obtained from both the bulk Ge device (2(a) and the Ge on Alumina device (2(b) As can be seen the bulk Ge showed better transistor characteristics exhibiting an effective mobility of 480 cm/Vs compared to 150cm/Vs. The Ge on Alumina substrate also shows significant series resistance. The decline in device performance was thought to be due to the poor surface roughness of the Ge on Al layer after polishing. It was found that by the addition of NaOCL into the polish process an improvement in the surface roughness of germanium was achieved from 2.5nm to 0.8nm. Subsequently transistors fabricated on the improved reworked Ge layer produced improved characteristics comparable to those obtained in bulk Ge. Characteristics shown in figure 3 exhibit an effective mobility of 414 cm/Vs Low temperature investigation of the transistor operation on the Ge on Al devices was carried out over a range of temperatures from room temperature to 173 K on transistors having a W/L of 9. A MDC model 441 cryogenic probe station in combination with Agilent B1500 parameter analyser was employed for low temperature measurement. Device characteristics were seen to improve with an increase in effective mobility (meff) and decrease in Sub threshold slope (S) observed with decreasing temperature. The improvement in transistor effective mobility is shown in figure 4. Table 1 offers a summary of the change in device characteristics with decreasing temperature.", "author_names": [ "Paul Baine", "Yee H Low", "Paul Rainey", "Harold S Gamble", "Mervyn Armstrong", "N Mitchell", "David W McNeill" ], "corpus_id": 137713894, "doc_id": "137713894", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Circular Geometry Transistors Fabricated on Germanium on Alumina Bonded Substrates", "venue": "", "year": 2010 } ]
Semiconductor clusters, nanocrystals, and quantum dots
[ { "abstract": "Current research into semiconductor clusters is focused on the properties of quantum dots fragments of semiconductor consisting of hundreds to many thousands of atoms with the bulk bonding geometry and with surface states eliminated by enclosure in a material that has a larger band gap. Quantum dots exhibit strongly size dependent optical and electrical properties. The ability to join the dots into complex assemblies creates many opportunities for scientific discovery.", "author_names": [ "A Paul Alivisatos" ], "corpus_id": 98248597, "doc_id": "98248597", "n_citations": 9082, "n_key_citations": 63, "score": 1, "title": "Semiconductor Clusters, Nanocrystals, and Quantum Dots", "venue": "Science", "year": 1996 }, { "abstract": "Recent advances in strategies for synthesizing nanoparticles such as semiconductor quantum dots, magnets and noble metal clusters have enabled the precise control of composition, size, shape, crystal structure, and surface chemistry. The distinct properties of the resulting nanometre scale building blocks can be harnessed in assemblies with new collective properties, which can be further engineered by controlling interparticle spacing and by material processing. Our study is motivated by the emerging concept of metamaterials materials with properties arising from the controlled interaction of the different nanocrystals in an assembly. Previous multi component nanocrystal assemblies have usually resulted in amorphous or short range ordered materials because of non directional forces or insufficient mobility during assembly. Here we report the self assembly of PbSe semiconductor quantum dots and Fe2O3 magnetic nanocrystals into precisely ordered three dimensional superlattices. The use of specific size ratios directs the assembly of the magnetic and semiconducting nanoparticles into AB13 or AB2 superlattices with potentially tunable optical and magnetic properties. This synthesis concept could ultimately enable the fine tuning of material responses to magnetic, electrical, optical and mechanical stimuli.", "author_names": [ "Franz X Redl", "K -S Cho", "Christopher B Murray", "Stephen O'Brien" ], "corpus_id": 4379969, "doc_id": "4379969", "n_citations": 632, "n_key_citations": 5, "score": 0, "title": "Three dimensional binary superlattices of magnetic nanocrystals and semiconductor quantum dots", "venue": "Nature", "year": 2003 }, { "abstract": "Understanding the surface of semiconductor nanocrystals (NCs) prepared using colloidal methods is a long standing goal of paramount importance for all their potential optoelectronic applications, which remains unsolved largely because of the lack of site specific physical techniques. Here, we show that multidimensional 113Cd dynamic nuclear polarization (DNP) enhanced NMR spectroscopy allows the resolution of signals originating from different atomic and magnetic surroundings in the NC cores and at the surfaces. This enables the determination of the structural perfection, and differentiation between the surface and core atoms in all major forms of size and shape engineered CdSe NCs: irregularly faceted quantum dots (QDs) and atomically flat nanoplatelets, including both dominant polymorphs (zinc blende and wurtzite) and their epitaxial nanoheterostructures (CdSe/CdS core/shell quantum dots and CdSe/CdS core/crown nanoplatelets) as well as magic sized CdSe clusters. Assignments of the NMR signals to specific crystal facets of oleate terminated ZB structured CdSe NCs are proposed. Significantly, we discover far greater atomistic complexity of the surface structure and the species distribution in wurtzite as compared to zinc blende CdSe QDs, despite an apparently identical optical quality of both QD polymorphs.", "author_names": [ "Laura Piveteau", "Ta-Chung Ong", "Brennan J Walder", "Dmitry N Dirin", "Daniele Moscheni", "Barbara Schneider", "Janine Baer", "Loredana Protesescu", "Norberto Masciocchi", "Antonietta Guagliardi", "Lyndon Emsley", "Christophe Coperet", "Maksym V Kovalenko" ], "corpus_id": 52900697, "doc_id": "52900697", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Resolving the Core and the Surface of CdSe Quantum Dots and Nanoplatelets Using Dynamic Nuclear Polarization Enhanced PASS PIETA NMR Spectroscopy", "venue": "ACS central science", "year": 2018 }, { "abstract": "The insertion of intentional impurities, commonly referred to as doping, into colloidal semiconductor quantum dots (QDs) is a powerful paradigm for tailoring their electronic, optical, and magnetic behaviors beyond what is obtained with size control and heterostructuring motifs. Advancements in colloidal chemistry have led to nearly atomic precision of the doping level in both lightly and heavily doped QDs. The doping strategies currently available, however, operate at the ensemble level, resulting in a Poisson distribution of impurities across the QD population. To date, the synthesis of monodisperse ensembles of QDs individually doped with an identical number of impurity atoms is still an open challenge, and its achievement would enable the realization of advanced QD devices, such as optically/electrically controlled magnetic memories and intragap state transistors and solar cells, that rely on the precise tuning of the impurity states (i.e. number of unpaired spins, energy and width of impurity levels) within the QD host. The only approach reported to date relies on QD seeding with organometallic precursors that are intrinsically unstable and strongly affected by chemical or environmental degradation, which prevents the concept from reaching its full potential and makes the method unsuitable for aqueous synthesis routes. Here, we overcome these issues by demonstrating a doping strategy that bridges two traditionally orthogonal nanostructured material systems, namely, QDs and metal quantum clusters composed of a \"magic number\" of atoms held together by stable metal to metal bonds. Specifically, we use clusters composed of four copper atoms (Cu4) capped with d penicillamine to seed the growth of CdS QDs in water at room temperature. The elemental analysis, performed by electrospray ionization mass spectrometry, X ray fluorescence, and inductively coupled plasma mass spectrometry, side by side with optical spectroscopy and transmission electron microscopy measurements, indicates that each Cu:CdS QD in the ensemble incorporates four Cu atoms originating from one Cu4 cluster, which acts as a \"quantized\" source of dopant impurities.", "author_names": [ "Beatriz Santiago-Gonzalez", "Angelo Monguzzi", "Valerio Pinchetti", "Alberto Casu", "Mirko Prato", "Roberto Lorenzi", "Marcello Campione", "Norberto Chiodini", "Carlo Santambrogio", "Francesco Meinardi", "Liberato Manna", "Sergio Brovelli" ], "corpus_id": 206711322, "doc_id": "206711322", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "\"Quantized\" Doping of Individual Colloidal Nanocrystals Using Size Focused Metal Quantum Clusters.", "venue": "ACS nano", "year": 2017 }, { "abstract": "Magic sized clusters (MSCs) of semiconductor are typically defined as specific molecular scale arrangements of atoms that exhibit enhanced stability. They often grow in discrete jumps, creating a series of crystallites, without the appearance of intermediate sizes. However, despite their long history, the mechanism behind their special stability and growth remains poorly understood. It is particularly difficult to explain experiments that have shown discrete evolution of MSCs to larger sizes well beyond the \"cluster\" regime and into the size range of colloidal quantum dots. Here, we study the growth of MSCs, including these larger magic sized CdSe nanocrystals, to unravel the underlying growth mechanism. We first introduce a synthetic protocol that yields a series of nine magic sized nanocrystals of increasing size. By investigating these crystallites, we obtain important clues about the mechanism. We then develop a microscopic model that uses classical nucleation theory to determine kinetic barriers and simulate the growth. We show that magic sized nanocrystals are consistent with a series of zinc blende crystallites that grow layer by layer under surface reaction limited conditions. They have a tetrahedral shape, which is preserved when a monolayer is added to any of its four identical facets, leading to a series of discrete nanocrystals with special stability. Our analysis also identifies strong similarities with the growth of semiconductor nanoplatelets, which we then exploit to further increase the size range of our magic sized nanocrystals. Although we focus here on CdSe, these results reveal a fundamental growth mechanism that can provide a different approach to nearly monodisperse nanocrystals.", "author_names": [ "Aniket S Mule", "Sergio Mazzotti", "Aurelio A Rossinelli", "Marianne Aellen", "P Tim Prins", "Johanna C van der Bok", "Simon F Solari", "Yannik M Glauser", "Priyank V Kumar", "Andreas Riedinger", "David J Norris" ], "corpus_id": 231650567, "doc_id": "231650567", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Unraveling the Growth Mechanism of Magic Sized Semiconductor Nanocrystals.", "venue": "Journal of the American Chemical Society", "year": 2021 }, { "abstract": "Understanding the pathways of hot exciton relaxation in photoexcited semiconductor nanocrystals, also called quantum dots (QDs) is of paramount importance in multiple energy, electronics and biological applications. An important nonradiative relaxation channel originates from the nonadiabatic (NA) coupling of electronic degrees of freedom to nuclear vibrations, which in QDs depend on the confinement effects and complicated surface chemistry. To elucidate the role of surface ligands in relaxation processes of nanocrystals, we study the dynamics of the NA exciton relaxation in Cd(33)Se(33) semiconductor quantum dots passivated by either trimethylphosphine oxide or methylamine ligands using explicit time dependent modeling. The large extent of hybridization between electronic states of quantum dot and ligand molecules is found to strongly facilitate exciton relaxation. Our computational results for the ligand contributions to the exciton relaxation and electronic energy loss in small clusters are further extrapolated to larger quantum dots.", "author_names": [ "Svetlana V Kilina", "Kirill A Velizhanin", "Sergei Ivanov", "Oleg V Prezhdo", "Sergei Tretiak" ], "corpus_id": 207638890, "doc_id": "207638890", "n_citations": 95, "n_key_citations": 3, "score": 0, "title": "Surface ligands increase photoexcitation relaxation rates in CdSe quantum dots.", "venue": "ACS nano", "year": 2012 }, { "abstract": "Surface effects significantly influence the functionality of semiconductor nanocrystals. High quality nanocrystals can be achieved with good control of surface passivation by various hydrophobic ligands. In this work, the chemistry between CdSe quantum dots and common surface capping ligands is investigated using density functional theory (DFT) We discuss the electronic structures and optical properties of small CdSe clusters controlled by their size of particle, self organization, capping ligands, and positive charges. The chosen model ligands reproduce good structural and energetic description of the interactions between the ligands and quantum dots. In order to capture the chemical nature and energetics of the interactions between the capping ligands and CdSe quantum dots, we found that PMe3 is needed to adequately model trioctylphosphine (TOP) NH3 is sufficient for amines, while OPH2Me could be used to model trioctylphosphine oxide. The relative binding interaction strength between ligands was found to decrease in order Cd O Cd N Cd P with average binding energy per ligand being 25 kcal/mol for OPH2Me, 20 kcal/mol for NH3 and 10 kcal/mol for PMe3. Charges on studied stoichiometric clusters were found to have a significant effect on their structures, binding energies, and optical properties.", "author_names": [ "Ping Yang", "Sergei Tretiak", "Sergei Ivanov" ], "corpus_id": 98044571, "doc_id": "98044571", "n_citations": 33, "n_key_citations": 0, "score": 0, "title": "Influence of Surfactants and Charges on CdSe Quantum Dots", "venue": "", "year": 2011 }, { "abstract": "The International Conference on Semiconductor Quantum Dots (QD2002) was held at Komaba Campus of University of Tokyo, Japan, from Monday, 30 September, through Thursday, 3 October 2002. The purpose of the QD2002 was to bring together scientists from different fields of physics and chemistry to discuss topics of common interest and significance in such growing areas including semiconductor quantum dots, nanocrystals, and clusters. The conference was focused on the optical and electronic properties of three dimensionally confined nanostructures grown both by epitaxial methods and chemical preparation routes. The QD2002 was the second in a series which started in Munich, Germany, in 2000. The scope of the QD2002 covered various research fields including novel fabrication techniques of nanoheterostructures, electronic structures, optical properties, electronic properties/single electron tunneling processes, molecular dots, nanocrystals, device applications such as lasers and memories, coherent processes/quantum computations, and biomedical applications.", "author_names": [ "Yasuhiko Arakawa", "Seigo Tarucha" ], "corpus_id": 97157537, "doc_id": "97157537", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Proceedings of the 2nd International Conference on Semiconductor Quantum Dots (QD2002)", "venue": "", "year": 2003 }, { "abstract": "physica status solidi (c) conferences and critical reviews publishes conference proceedings, ranging from large international meetings to specialized topical workshops as well as collections of topical reviews on various areas of current solid state physics research. The International Conference on Semiconductor Quantum Dots (QD2002) was held at Komaba Campus of University of Tokyo, Japan, from Monday 30 September through Thursday 3 October 2002. The purpose of the QD2002 was to bring together scientists from different fields of physics and chemistry to discuss topics of common interest and significance in such growing areas including semiconductur quantum dots, nanocrystals, and clusters. The conference was focused on the optical and electronic properties of three dimensionally confined nanostructures grown both by epitaxial methods and chemical preparation routes. The QD2002 was the second in a series which started in Munich, Germany, in 2000. The scope of QD2002 covered various research fields including novel fabrication techniques of nanoheterostructures, electronic structures, optical properties, electronic properties/single electron tunneling processes, molecular dots, nanocrystals, device applications such as lasers and memories, coherent processes/quantum computations, and biomedical applications.", "author_names": [ "Huang Chuan Tai Yan", "Zun Cha Qing Wu" ], "corpus_id": 92957793, "doc_id": "92957793", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Proceedings of the 2nd international conference on semiconductor quantum dots, Tokyo, Japan 30 September 3 October 2002", "venue": "", "year": 2003 }, { "abstract": "Abstract Sol gel transition is a second order phase transition depending on the creation of the macroscopic solute network, which confines the solvent in its pores. The phase transition from the sol state to the gel state takes place, when small clusters of molecules join together and create one huge cluster, which fills most of the volume of the sample. The aim of this paper is to study the phase transition process using as detectors the semiconductor PbS nanocrystals, called quantum dots, embedded in the solution. As a material we are using the aqueous solution of gelatin, which creates the gel network due to hydrogen bonds between monomers belonging to different chains. The lifetimes of excitons generated in quantum dots by the light pulse appear to be very sensitive to the polymer surrounding. These lifetimes have been measured by use of the transient absorption spectroscopy. In order to show the dynamics of the gelation process the measurements were performed with appropriate time lags in train of the process duration. It appears that dynamics of the exciton lifetime significantly changes during the sol gel transition, what allows the indication of the gel point in the system and the appropriate universal critical exponents.", "author_names": [ "Piotr Piatkowski", "B Ratajska-Gadomska", "Wojciech Gadomski" ], "corpus_id": 98101589, "doc_id": "98101589", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Probing slow dynamics by ultrafast process: Sol gel transition detected by transient absorption spectroscopy of quantum dots", "venue": "", "year": 2012 } ]
Defect engineering in thermoelectric materials: what have we learned?
[ { "abstract": "Thermoelectric energy conversion is an all solid state technology that relies on exceptional semiconductor materials that are generally optimized through sophisticated strategies involving the engineering of defects in their structure. In this review, we summarize the recent advances of defect engineering to improve the thermoelectric (TE) performance and mechanical properties of inorganic materials. First, we introduce the various types of defects categorized by dimensionality, i.e. point defects (vacancies, interstitials, and antisites) dislocations, planar defects (twin boundaries, stacking faults and grain boundaries) and volume defects (precipitation and voids) Next, we discuss the advanced methods for characterizing defects in TE materials. Subsequently, we elaborate on the influences of defect engineering on the electrical and thermal transport properties as well as mechanical performance of TE materials. In the end, we discuss the outlook for the future development of defect engineering to further advance the TE field.", "author_names": [ "Tyler J Slade", "Lei Hu", "Xian Yi Tan", "Yubo Luo", "Zhong-Zhen Luo", "Jianwei Xu", "Qingyu Yan", "Mercouri G Kanatzidis" ], "corpus_id": 235461010, "doc_id": "235461010", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Defect engineering in thermoelectric materials: what have we learned?", "venue": "Chemical Society reviews", "year": 2021 }, { "abstract": "For decades, zone melted Bi2Te3 based alloys have been the most widely used thermoelectric materials with an optimal operation regime near room temperature. However, the abundant waste heat in the mid temperature range poses a challenge; namely, how and to what extent the service temperature of Bi2Te3 based alloys can be upshifted to the mid temperature regime. We report herein a synergistic optimization procedure for Indium doping and hot deformation that combines intrinsic point defect engineering, band structure engineering and multiscale microstructuring. Indium doping modulated the intrinsic point defects, broadened the band gap and thus suppressed the detrimental bipolar effect in the mid temperature regime; in addition, hot deformation treatment rendered a multiscale microstructure favorable for phonon scattering and the donor like effect helped optimize the carrier concentration. As a result, a peak value of zT of ~1.4 was attained at 500 K, with a state of the art average zTav of ~1.3 between 400 and 600 K in Bi0.3Sb1.625In0.075Te3. These results demonstrate the efficacy of the multiple synergies that can also be applied to optimize other thermoelectric materials. A popular material for converting heat into electricity can now operate at elevated temperatures associated with industrial machinery. Bismuth tellurium is a thermoelectric alloy that works at room temperature and finds use in refrigeration and powergeneration, but much waste heat is created in the so called middle temperature range of 100 300 degrees Celsius. Tiejun Zhu from Zhejiang University and colleagues doped indium atoms into bismuth tellurium to provide a balance to the excess, thermally activated charge carriers that normally materialize when this alloy is heated to middle temperatures. Hot deformations of the alloy during fabrication introduced missing atom defects and micrograins that worked together with dopants to scatter heat transporting phonon waves and optimize carrier concentrations. Thermoelectric and X ray testing revealed that the doped alloyhad a higher working temperature and better mechanical properties. We herein report a synergistic optimization procedure that combines point defect engineering, band structure engineering and multiscale microstructuring in p type (Bi,Sb)2Te3 thermoelectric materials by Indium doping and hot deformation. As a result, a peak value of zT ~1.4 was attained in Bi0.3Sb1.625In0.075Te3 at 500 K, along with a state of the art average zTav of ~1.3 between 400 and 600 K. These results demonstrate the efficacy of the multi synergies that can also be applied to optimize other thermoelectric materials.", "author_names": [ "Zhaojun Xu", "Haijun Wu", "Tiejun Zhu", "Chenguang Fu", "Xiao-hua Liu", "Lipeng Hu", "Jian He", "Jiaqing He", "Xinbing Zhao" ], "corpus_id": 138662984, "doc_id": "138662984", "n_citations": 72, "n_key_citations": 0, "score": 0, "title": "Attaining high mid temperature performance in (Bi,Sb)2Te3 thermoelectric materials via synergistic optimization", "venue": "", "year": 2016 }, { "abstract": "Numerous endeavors have been made to advance thermoelectric SnTe for potential applications. Effective strategies focus on the manipulation of transport properties, including valence band convergence, resonate state, and defect engineering. It has been demonstrated that alloying trivalent Bi or chalcogenide SnSe alone in SnTe can trigger an inherent enhancement of thermoelectric performance. However, what the critical role in the transport valence band co doping Bi and Se in SnTe plays is still unclear. Particularly, fully evaluating the effect of band convergence on the carrier concentration dependent weighted mobility, which dominates the electronic performance, is primary and essential for designing excellent thermoelectric materials. Here, we report that Bi doping in SnTe SnSe alloys can derive a distinct decrease in the energy offset between the two valence bands, thus improving the density of state effective mass by only slightly deteriorating the mobility. The well established theoretical model reveals that the Bi doping induced band convergence and the optimized carrier concentration actually enhance the weighted mobility, contributing to the improvement of electronic performance. Moreover, the Debye Callaway model demonstrates the origin of the reduced lattice thermal conductivity. The present results confirm the potential of transport engineering in promoting thermoelectric performance.", "author_names": [ "Xuming Guo", "Zhiyu Chen", "Jingyou Tang", "Fu Chun Zhang", "Yan Zhong", "Hangtian Liu", "Ran Ang" ], "corpus_id": 216308029, "doc_id": "216308029", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Thermoelectric transport properties in Bi doped SnTe SnSe alloys", "venue": "", "year": 2020 }, { "abstract": "R Trailblazer. Maverick. These are adjectives often used to describe celebrities and politicians, but rarely attributed to scientists. However, in the case of Mildred Dresselhaus, who died earlier in 2017 at age 86, these superlatives were spot on. Dresselhaus, known as the \"queen of carbon,\" was a pioneer in the fi eld of nanoscience. She carried out a series of experiments that led to a fundamental understanding of the electronic structure of semi metals, especially graphite, along with carbon nanotubes and graphene. A Massachusetts Institute of Technology (MIT) professor emerita of physics and of electrical engineering and computer science, she was also well known for being the fi rst to exploit the thermoelectric effect at the nanoscale, effi ciently harvesting energy from the temperature differences in materials that conduct electricity. The co author of eight books and some 1700 papers, she supervised more than 60 doctoral students in her 50 years on the MIT faculty. To those in the materials science and engineering community, she was a prolifi c and innovative scientist, a well loved mentor, and a role model to hundreds of women (and men) in science and engineering. \"Professor Dresselhaus embodied what a scientist should be: bold, pioneering, kind, and dedicated to making the world a better place,\" says Jennifer Dionne, an associate professor of materials science and engineering at Stanford University and 2017 MRS Outstanding Young Investigator Award recipient. \"She was a huge inspiration for me, and I hope we all can help carry on her legacy for years to come.\" Alongside Dresselhaus's outstanding research accomplishments was her long standing commitment to promoting gender equity in science and engineering. In 1971, she and a colleague organized the fi rst Women's Forum at MIT to discuss the roles of women in science and engineering. She received a Carnegie Foundation grant in 1973 to support her efforts to encourage women to enter traditionally male dominated fi elds of science and engineering. For a number of years, she led an MIT seminar in engineering for fi rst year female students designed to build their confi dence. In 2015, Dresselhaus delivered the keynote address at a three day workshop for female graduate students and postdocs considering careers in academic research, \"Rising Stars.\" Her remarks, on the importance of persistence, described her interactions with Nobel laureate Enrico Fermi during morning walks to the laboratory at The University of Chicago. Previously, she said during a 2012 interview with the Kavli Foundation, \"What I learned from him [Fermi] was the importance of having a very broad understanding of science, so you can take advantage of new science opportunities so that you can really serve society.\" In comparison, Dresselhaus noted in the same interview, which she gave when she received the Kavli Prize, \"my advisor didn't know what I was working on until two weeks before I submitted my PhD thesis. He never talked with me because he didn't think women should be in science.\" Her primary message to the workshop attendees was persistence. \"It was what you did that counted, and that followed me through life,\" she said.", "author_names": [ "Aditi S Risbud" ], "corpus_id": 139665045, "doc_id": "139665045", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Millie Dresselhaus: Our science celebrity", "venue": "", "year": 2017 }, { "abstract": "Our colleague and friend, Fu Zhai Cui, has decided to step down from his position as Co Editor in Chief of Biomedical materials (BMM) at the end of the year due to other commitments. BMM would not be the journal that it is, and we two would not have served as participants in its development, were it not for Fu Zhai. It was his vision and hard work that gave birth to BMM. Fu Zhai's e mail to Dr Mingfang Lu at IOP Publishing in June of 2005 initiated the process that led to the new journal being established. Underscoring the importance of such an endeavor, Fu Zhai noted that biomedical materials and tissue engineering and their applications had been rapidly developing in recent years and the trend was likely to continue for many years, that there were relatively few journals capable of handling these subjects, and even fewer journals that faced East as well as West. There are several features of Fu Zhai's professional life which have added to the character of BMM and which reflect, and perhaps even help to explain, his country's remarkable development: resourcefulness, innovation, and drive. When we first met Fu Zhai at Tsinghua University more than 15 years ago, the facilities available to him were notably limited, especially in comparison to those that we had access to at our respective institutions. There was almost a complete absence of biomaterials related journals at Tsinghua, prompting us to consider ways in which we could send our surplus issues to him. But Fu Zhai made the most of what resources he did have and directed his students in important and productive research that was published in leading English language journals. Fu Zhai never let his thinking and efforts be constrained by limited resources. The projects undertaken by Fu Zhai and his students at Tsinghua have always displayed engineering innovation born of scientific understanding. He is either investigating biomaterials for new applications or taking novel approaches for the production of new types of biomaterials. In both cases, his work is founded on knowledge drawn from an array of scientific studies and his success is due in large part to the multidisciplinary teams that he assembles. For example, Fu Zhai's group was one of the first in the world to employ biomaterial implants (hyaluronic acid hydrogels) for the treatment of brain defects, thus pioneering the area of brain tissue engineering. For other biomaterials applications, such as bone tissue engineering, Fu Zhai took the biomimetic approach of producing mineralized collagen scaffolds. But he did so in the novel way of co precipitating collagen and hydroxyapatite to favor self assembly and a hierarchical microstructure. Fu Zhai's insights into the mineralization process were derived in part from his own studies with Heng De Li, one of the pioneers of biomineralization. Biomaterials researchers frequently think about the potential clinical applications of their developments, but rarely find or make the opportunity to commercialize their products. Fu Zhai acted on translational research before that term entered the researcher's lexicon. He orchestrated the compilation of pre clinical data and engaged his clinical colleagues in the necessary human trials to demonstrate the safety and efficacy of his mineralized collagen scaffolds for spine fusion and other applications. After having been approved by the China medical device regulatory process, the product is now being used in clinics. A journal like BMM would like to be known for publishing papers which exemplify some of the same traits that Fu Zhai has demonstrated in his own career: resourcefulness, innovation, and clinical utility. Moreover, Fu Zhai has shown by his own example why he was so right to have seen the importance of establishing a truly international biomaterials journal. We both look forward to continuing in the capacity of Co Editors in Chief, with the confidence that comes with knowing that our friend, Fu Zhai Cui, will be available to advise us.", "author_names": [ "In-seop Lee", "Myron Spector" ], "corpus_id": 109025246, "doc_id": "109025246", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Fu Zhai Cui's vision and leadership", "venue": "", "year": 2010 }, { "abstract": "Including students in special practice curriculums, such as the one initiated by University of Agricultural Sciences and Veterinary Medicine Cluj Napoca, they become more aware of the entire process in the food industry, from the acquisition, reception, management of primary and auxiliary materials, to the importance of hygiene, protective equipment, the temperature and operating mode and the sales of the final products. The aim of the study is to evaluate the impact of practical train ing and its role in transforming students in future eng ineers better prepared for the labor market. Introduction While the university remains a cultural instituti on, creating value, not for a moment forget that the purpose for which it r eceives funding or that students pay taxes is not to form people of culture, but to provide speci alists in certain economic and social fields (Mihailescu, 2007) The aim of the study is to evaluate the impact of p ractical training for Food Science and Technology students in terms of overall impact on competences in the European food industry to produce safe, high quality and varied f oods that meet the needs of consumers. Materials and Methods. For the study we have analyzed and evaluated the s tudents during their practice programs. We had short discus sions with them individually about their likes and dislikes related to the individual progra ms. Students of the Faculty of Agriculture from UASMV Cluj Napoca are performing practice programs during the 2nd and 3rd year of ba chelor program, through fully equipped Pilot plants such as Milk dairy products, Meat and meat products, Brewery Plant and Bread bakery belonging to the Food Engineering Department. In these pilot plants the students are trained by technicians and academic staff to partic ipate in food technology production. This is important because the young students learn about al l the processes, becoming responsible in turn with: evaluate the raw materials inputs, purch asing, receiving and controlling the production in authorized laboratory, HACCP monitoring, labeling, delivery, sale. All these play an important role in supporting the knowledge accumulated in courses and laboratories and providing an overview on produ ction and its problems, on responsibilities that they might have as Engineers Food control specialist. They improve their competences learning these things by own, inc luding methods to correct problems or manufacturing defects that can occur. This is important because in the current economy we should check students especially at the output, not just at the input, ho w they are prepared for the labor market. The practical training is intended to improve the old w ay of teaching. Each teacher is normally concerned only with his discipline. Teachers do not gather together to tell the student \"Look in your job, you do this and that. For this, take w hat you learned from the field X and combine what you learned in the field Y and find a solution Our education is focused towards", "author_names": [ "Andrei Borsa", "Sevastita Muste", "Maria Tofana", "Andruta Elena Muresan" ], "corpus_id": 167798812, "doc_id": "167798812", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The impact of practical training and professional development for students in enhancing European competences in Food Science and Technology", "venue": "", "year": 2012 }, { "abstract": "Nature is the largest laboratory that ever existed and ever will. In addressing its challenges through evolution Nature tested every field of science and engineering leading to inventions that work well and last. Nature has \"experimented\" with various solutions and over billions of years it has improved the successful ones. It has always served as a model for mimicking and inspiration to humans in their efforts to improve their life. Adapting mechanisms and capabilities from nature and using scientific approaches led to effective materials, structures, tools, mechanisms, processes, algorithms, methods, systems and many other benefits. The subject of copying, imitating, and learning from biology was coined Biomimetics by Otto H. Schmitt in 1969. This field is increasingly involved with emerging subjects of science and engineering and it represents the studies and imitation of nature's methods, designs and processes. Biologically inspired technologies are making it possible to consider developing such devices as prosthetics that feel and operate like the \"real thing\" as well as engineering robots that look and behave as human and animals. Mimicking Nature involves many challenges and requires significant technology advances. To promote advances in the field of electroactive polymers (EAP) that is know as artificial muscles, the author posed in 1999 an armwrestling challenge for a match between human and a robotic arm that is driven by these materials. A contest is now held annually and it is providing a measure of the advances in the field of EAP and the ability to mimic the performance of muscles. A review will be given of selected areas that were inspired by nature with emphasis on EAP and an outlook for potential future development in biomimetics. Program Guide and Abstracts 6 Blackledge, Todd A. Spider silk: a 400 million year experiment in materials science Department of Biology, University of Akron, Akron, OH 44325 3908, USA Abstract: Spider dragline silk has a number of enticing properties for the production of biomimetic fibers, in particular high tensile strength and extreme toughness. However, silk also plays an integral role in the ecology of spiders including protection against predators or the environment, capture of prey, dispersal, communication, and reproduction. Furthermore, orb weaving spiders can produce at least seven different types of silk that are composed of different sets of proteins. The material properties of these silk fibers result from how the constituent proteins of silk fibers are assembled and Spider dragline silk has a number of enticing properties for the production of biomimetic fibers, in particular high tensile strength and extreme toughness. However, silk also plays an integral role in the ecology of spiders including protection against predators or the environment, capture of prey, dispersal, communication, and reproduction. Furthermore, orb weaving spiders can produce at least seven different types of silk that are composed of different sets of proteins. The material properties of these silk fibers result from how the constituent proteins of silk fibers are assembled and interact with one another and are likely to have been shaped by natural selection on the ways in which each silk interacts with the environment. Therefore, the biomechanical study of spider silk can potentially link together research ranging from the evolution of silk genes through the ecological function of webs or other silk structures. Here, I discuss how research on the biological diversity of silks spun by spiders can facilitate efforts to synthesize biomimetic fibers. Program Guide and Abstracts 7 Bras, Bert. Inclusion of biologically inspired design into mechanical engineering design classes School of Mechanical Engineering, Georgia Institute of Technology Abstract. In this talk, we will present our experiences with including biomimetic In this talk, we will present our experiences with including biomimetic principles into mechanical engineering design classes. The goals are 1) to expose engineering students and practitioners to biomimicry and 2) to gain insight into the efficiency and effectiveness of using biomimetic approaches to solving engineering design problems. Specifically, our experience with ME 4182 Capstone Design will be highlighted. The initial experiment consisted of including biology undergraduate students as project consultants for the engineering design teams. Experiences from the engineering students (through surveys and informal feedback) biology students and faculty will be presented. Selected projects will be highlighted to illustrate the effectiveness, shortcomings, and barriers to biomimetic approaches. Lessons learned and suggestions for future experiments, implementations and expansion will be given. Program Guide and Abstracts 8 Clark, Robert. Biologically Inspired Materials and Material Systems Duke University. Abstract. It is clear that our biological and medical community is now at a point of incredible opportunity. The collective biological sciences (biological, biophysical, biochemical, biocomputational, and biomedical) have generated a plethora of information regarding complex biological systems, especially at the microcellular and nanomolecular levels. It is time to bring these research advances into the core curriculum for all students interested in careers that require a more detailed and mechanistic understanding of the biological world, disease, and medicine. It is clear that our biological and medical community is now at a point of incredible opportunity. The collective biological sciences (biological, biophysical, biochemical, biocomputational, and biomedical) have generated a plethora of information regarding complex biological systems, especially at the microcellular and nanomolecular levels. It is time to bring these research advances into the core curriculum for all students interested in careers that require a more detailed and mechanistic understanding of the biological world, disease, and medicine. We recognized several years ago that a more rigorous mapping of engineering onto the biological sciences might yield more mechanistic information about nature's own technologies. Our approach is to recognize that Biology (Nature) itself can be viewed as an \"engineered system\" and that much of Biology's systems function (and dysfunction) at cellular (micro) and molecular (nano) scales. At these scales we explore a more formal \"Mapping of Engineering onto Biology,\" for both health and disease, and new technological innovation. This defines our approach towards bioinspiration. Framing this approach, we recognize: (1) Biology as a series of cellular products, nano components, energy consuming processes, and functioning devices that are \"manufactured\" with a limited set of materials, that nevertheless overcome the same physical and chemical limitations (force, temperature, pressure, E fields, time, solubility, diffusion, etc. as other inorganic materials, but do it to support life; (2) disease, either due to defects in manufacturing, (genetic based) or toxic insult (environmental based) as an opportunity to detect and characterize what has changed compared to the \"normal state\" (3) medicine, as a tool for prevention or cure, again at the gene based manufacturing level, or by drug or biocompatible prosthetic intervention. This mapping framework is directed towards organizing and generating extensive information that at present is missing concerning the physical and chemical properties of cellular, intracellular, and membrane components that will lead to a greater understanding of how the molecular machines that drive healthy processes are built and function. From this knowledge, we can then understand failures in these components that lead to disease or gain inspiration in the design of new materials and devices for humanity. Such an approach places existing (and future) knowledge, especially of cell and molecular biology, fairly and squarely in the realm of engineering materials and design methodology. It is, then, a formal Engineering Design Methodology, and a better understanding of the complex relationships between cellular and molecular material's composition, structure, properties and performance (CSPP) that is the cornerstone of our reverse and forward engineering exercises motivated by basic questions in the biological sciences. The Center for Biologically Inspired Materials and Material Systems at Duke University was founded to establish an integrative educational and research environment for students, faculty, and staff. The structure of the Center, mechanisms for fostering research and collaborative educational activities, and a few examples of results from these efforts will be", "author_names": [ "Kartik Sundar", "Lena H Ting" ], "corpus_id": 16060672, "doc_id": "16060672", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Program Guide and Abstracts GENERAL INFORMATION All sessions will be held in Auditorium 236 in the", "venue": "", "year": 2006 }, { "abstract": "Pattern formation and evolution in liquid crystal polymers is studied in both static situation as well in applied magnetic and flow fields. Observations of nucleation and growth of nematic domains in an isotropic matrix under static conditions were used to establish the origins of the most common types of point defects. The patterns describing the director field distribution were revealed using a solidification induced banding method on quenched samples. At a low percent conversion of isotropic to nematic, the defect density is dominated by domain density and by anchoring conditions between the nematic domains and the isotropic matrix. At higher percent conversions, the defect density is controlled by domain domain interaction events. The defect density rises as the domains nucleate and impinge but decreases after the generation of defects of negative strengths and an annihilation process begins. Larger domains created in the coalescence process can then grow and impinge and continue defect generation via domain interaction. The absence of negative strength defects during the preimpingement phase indicates these defects arise solely due to the domain domain coalescence during the growth process. The subsequent effects of both magnetic fields and flow fields on defect structure are also examined. With respect to the former, a solution of the director orientation distribution function is presented for N6el inversion walls created in a liquid crystal by application of a magnetic field. The theoretical model is used to simulate director trajectories across walls as a function of both the elastic anisotropy and the orientation of the wall with respect to the applied field. The gradual transition of the defect structures from Neel bend walls to Neel splay walls as the angle between the wall and the magnetic field is varied is also presented. Experimental micrographs obtained via atomic force microscopy on a thermotropic liquid crystalline polymer are used to test and evaluate the theoretical model. Visualization of director textures using the lamellar decoration technique shows the theoretical and experimental results to be in good agreement. The results were used to determine that the sample had an elastic anisotropy of 0.5, implying that k, 3k 33 The effects of flow on the disclination textures were studied with an optical shearing cell. Flow visualization experiments were used to study curvature driven motion in disclination loops created during flow. Theories of differential geometry were used to predict the way the line curvature should evolve over time. Theoretically the relationship between velocity and local curvature is linear. Experimentally, deviations from the theory sometimes occurred due to forces of attraction between nearby disclinations. Even though disclination evolution in both small molecular and polymer liquid crystals obeyed similar physical laws, several significant differences were observed. Disclinations in the polymer systems generally displayed initially highly contorted contours. In the small molecule liquid crystals however, the loop contours consistently displayed very simple shapes. In the polymer system, the complex line shape reflects the many prior loop loop coalescence events due to the greater density of loops than in the low molar mass liquid crystal. Moreover, the reduction of regions of high loop curvature is inherently slower in the polymer liquid crystal due to the higher viscosity of the medium. In addition, the motion of the disclination contour may also be affected by a possible reduction in the mobility of disclinations due to the presence of lower molecular weight components at the defect core which themselves must diffuse along with the line defect. Thesis Supervisor: Edwin L. Thomas Title: Morris Cohen Professor of Materials Science and Engineering Acknowledgments: It is hard to believe that my 8+ years at MIT are coming to an end! Before departing there are many people I would like to thank. First I would like to express my appreciation to my advisor Professor Edwin Thomas, for his enthusiasm and support over the years. His excitement for scientific research made an indelible impression on me when I came to him as a sophomore in September of 1989 to inquire about undergraduate research opportunities in his group. Since that time he has taken great care in my professional development, something that has added significantly to my positive experience at MIT. As I reflect on the last 8 years I have worked for him, I am beginning to understand the advice given to me by one of his former students. One person in particular suggested that if I wanted to start research as a undergraduate I should \"go work for Ned Thomas\" That was it. No \"ifs\" \"ands\" or \"buts\" just \"do it\" When I look back now, if I had to do it over again I wouldn't have done anything differently. The lessons I have learned from Ned about academics, research, and group management are invaluable and will serve a foundation for some day in the future when I start my own research group. I am also very grateful to Professor Michael Rubner for his support, especially of my desires to become involved with teaching. The first time we worked together was in the Fall of 1992 when I was a grader for his course in Polymer Chemistry. He gave me his full support when I expressed an interest in also running review sessions and holding office hours in addition to my regular duties. I was honored when he asked me to become a fulltime graduate teaching assistant for him in the fall of 1995. The marvelous example he set in the classroom is something to which I aspire. His continued advice over the years is something that I have appreciated a great deal. There are many other people that have been instrumental in my career at MIT. I am very grateful to Professor Robert Rose for his guidance and support over the years. He has been one of the most influential professors I have interacted with and has been instrumental in my decision to become a professor. I would also like to thank the members of my committee: Professors Robert Armstrong, Ken Russell and Chris Scott for their advice and suggestions. Professor Sam Allen was also very instrumental in my research on curvature driven motion of disclination loops. Scott Clingman (Cornell University, Professor Chris Ober's group) was a main driving force in this research through the superb polymers he synthesized for me. I don't know what I would have done without him. I owe you one Scott! I also could not have done this without the continual support of my friends and family. I would like to thank Leslie Lawrence, Marshall Hughes, Dongsik Yoo and Barbara Dirsa for their friendship over the years. A big thank you is also due to Kevin McGinty, my piano teacher, who was not only a superb teacher but a good friend as well. He was one of the main people who helped me maintain my sanity while finishing my degree. The love and support of my parents, Paul and Lynda Gunther, helped pull me through the difficult moments. To all my brothers and sisters: Jordan, Jenessa, Jilenne, Julia, Jansen, Justus, and Jesse..yes! I am now Dr. Gunther! I am deeply indebted to my brother Jordan who spent nearly one week of his summer vacation helping me finish the final corrections on my thesis. I couldn't have done it without you! Finally, I would like to thank the Lord for his love and blessings and without whom none of this would have been possible.", "author_names": [ "Jane Davis Gunther" ], "corpus_id": 138926624, "doc_id": "138926624", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Defects in liquid crystal polymers their origins and behavior in magnetic and flow fields", "venue": "", "year": 1997 }, { "abstract": "Well, the theory of scattering of elastic waves is difficult. I don't want to minimize that, but I thought I might make a few diversionary introductory remarks. My first reference will be the Los Angeles Times of today, the astrology column. It advises those born under the sign of Leo to choose their words carefully to avoid trouble. That happens to be applicable to yours truly. I hope I do it. Disciplines Materials Science and Engineering Structures and Materials This 3. ultrasonic scattering 1 is available at Iowa State University Digital Repository: http:/lib.dr.iastate.edu/ cnde_yellowjackets_1975/21 BASIC tHEORY OF ULTRASONIC SCATTERING BY DEFECTS: NUMER ICAL STUDIES FEATURES FOR EXPERIMENTAL APPLICATION* i* J. A. Krumhansl Cornel l University Ithaca, New York Well, the theory of scattering of elastic waves is difficult. I don't want to minimize that, but I thought I might make a few diversionary introductory remarks. My first reference will be the Los Angeles Times of today, the astrology column. It advises those born under the sign of Leo to choose their words carefully to avoid trouble. That happens to be applicable to yours truly. I hope I do it. The second technique which has been found useful in the unruly audiences at Cornell is to show your last slide first or you'll never get there. So, that's what I want to do. Figure l (see Fig. 1 of the Appendix) is a threedimensional plot of elastic wave cross sections which we have calculated from 0 to 180deg as a function of ka. This is for a longitudinal plane wave incident on a spherical cavity in titanium, and this is the differential scattering cross section for the transverse component. The calculation is for all ka from 0 to 6. The experimentalist can, for example, if he prescribes the frequency spectrum, which is, of course, a range of ka, take a cut across this with his computer and estimate the total difference across section for a transversely polarized receiving transducer, with this incident longi tudinal wave We're cost conscious at the un iversity. This data presentation costs about a dollar and took three mi nutes. Now, given the end of the story, I don't know whether anybody is interested in my filling in the details but that's what I'm here for. So, let me proceed. We're doing this in the solid state theory group at Cornell. The people listed in the Appendix are the participants. We began in September 1974. Jim Gubernatis really deserves special mention for giving technical leadership to the program and seeing that it moved, and particularly for supervi sing a number of the computations. Without this help I don't think we would have gotten where we are. The rest of us are active participants. One l ast bit of perspective: the cost of this total program for this year is about that of two Tektronix scopes with ordinary software. It' s an interesting academic experiment. Can some denizens of a university theoretical physics group interact with engi neers? We've had a good time, and also learned a lot by interactions with Prof. Pao in the Cornel l Mechanics Department during the course of the past year. We tried to look around and see where we might make a contribution in the overall NDE program and the contribution we chose to make was to update the theory of scattering, and we found that it was sort of a cold water shock when you move from the simplicity of quantum mechani cs with its scalar fields To supplement th1s paper wh1ch was presented at the symposium, a technical surrmary article, \"Theory of the Scattering of Ultrasound by Flaws\" by J. E. Gubernatis, E. Domany, t~ Huberman, and J. A. Krumhansl, is incorporated as an Appendix. t Research sponsored by ARPA/AFML Center for Advanced NDE.", "author_names": [ "James A Krumhansl" ], "corpus_id": 118766106, "doc_id": "118766106", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Basic Theory of Ultrasonic Scattering by Defects: Numerical Studies and Features for Experimental Application", "venue": "", "year": 1975 }, { "abstract": "Let me begin by saying that this is part of a program which is very much complementary to and is helped by the experimental program; so I'll repeat, in part, some of the overview comments that Bruce Thompson made this morning. We've regarded our role as one of trying to plug into the overall program those aspects of the theory of elastic wave scattering which can be developed in a utilitarian way in terms of modern analytical and computational techniques, in a form which I hope can be useful in signal processing, interpretation, design of experiment, etc. To outline our point of view, I'm going to first give a survey of what we have been doing and then give some of the results. It's rather shocking to think of the amount of money that goes into an experimental program and its interpretation, if the interpretation is done in terms of acoustic or scalar wave scattering theories, when the differences from proper elastic theory can be as great as those which Bruce Thompson pointed to this morning. Disciplines Materials Science and Engineering This 9. defect characterization: fundamentals is available at Iowa State University Digital Repository: http:/lib.dr.iastate.edu/ cnde_yellowjackets_1976/33 INTERPRETATION OF ULTRASONIC SCATTERING MEASUREMENTS BY VARIOUS FLAWS FROM THEORETICAL STUDIES J. A. Krumhansl Cornell University Ithaca, New York Let me begin by saying that this is part of a program which is very much complementary to and is helped by the experimental program; so I'll repeat, in part, some of the overview comments that Bruce Thompson made this morning. We've regarded our role as one of trying to plug into the overall program those aspects of the theory of elastic wave scattering which can be developed in a utilitarian way in terms of modern analytical and computational techniques, in a form which I hope can be useful in signal processing, interpretation, design of experiment, etc. To outline our point of view, I'm going to first give a survey of what we have been doing and then give some of the results. It's rather shocking to think of the amount of money that goes into an experimental program and its interpretation, if the interpretation is done in terms of acoustic or scalar wave scattering theories, when the d1fferences from proper elastic theory can be as great as those which Bruce Thompson pointed to this morning. Now, there certainly has been a tremendous amount done on elastic wave scattering. There are some methods, however, which have now become practical because of the advances in our understanding of an analytical techniques and computers. The work I'm reporting on has been done primarily by Jim Gubernatis of Los Alamos, Eytan Domany and others at Cornell, and myself. The experimental work we have interacted strongly with is that of Tittmann at Rockwell and Adler of Tennessee. We have received stimulus from the ARPA MRC, Materials Research Council program, arid from Tony Mucciardi at Adaptronics, and from the Rockwell program in general. As I said, our program objective is to be utilitarian, and utilitarian means not necessarily simple. The diagnostics of ultrasonic flaw detection involve two aspects: where is the defect (the existence of a defect) and what is the defect? Perhaps the real justification of the extent to which we try to carry the theory is in this latter regard, doing everything we can to squeeze out whatever characteristic information we can from ultrasonic scattering data. Let me briefly outline the theoretical methods. A traditional method with which most of us are familiar for problems of this sort is to use normal mode expansions. Now, in textbooks and teaching,this method is useful, but the geometries chosen are always spheres. Once you go beyond spherical harmonics you find that,if not hopeless, life is at least extremely difficult. Programming some of the calculations is cumbersome, and non intuitive. At least some of the training in modern theoretical physics has enriched 164 the bag of tools which can be used, particularly with integral equation methods which have the advantage that one plugs in information which can be related rather directly to the experimental featur\"es of the si.tuation in question. They are also subject to approximation techniques such as iterationtry something, improve it ;try it again, improve itprinciple. With brute force large scale computers, one can hope to do some of these things inexpensively. Indeed, there are standard approximation methods that we use in nuclear scattering; Born approximation, variational methods, distorted wave methods and so forth,which provide a hunting license of sorts to see what one can do in the present context. Our first year's program, 1975, was largely concerned with establishing the theoretical base; the Cornell Materials Science Center report number 2654 presents a summary of the general theory, and provides detailed computer results for the Born approximation. The Born approximation simply inserts incident field displacement and strain at appropriate points in the integral formula as needed. This really doesn't solve the integral equation, but it's a first step, and has been very useful as an exploratory device. As the program has progressed we have tried to express the results of such a calculation concisely, and Jim Gubernatis has found that it's particularly useful to define something called an \"f vector\" which wi 11 give complete scattering data. It depends directly on the changes in material parameters, ~p, and directly on the changes in the elastic constant, ~c. In addition, we require a knowledge of the displacement and strain fields in the flaw region We are now in the process of using this approach. to examine carefully exact 1 imi ti ng behavior for low frequency. By utilizing all the information present in the longitudinal, transverse, and mode converted scattering,material parameter changes can be determined over and above any imaging or echo detection. Hopefully, microprocessors can eventually make the on line analysis cheap and easy. Now, I'd like to run through the main results we have obtained at Cornell during the past year. My colleagues have been Eytan Domany, Paul Muzikar, Steve Teitel, Dave Wood, and Jim Gubernatis, whose support came from Los Alamos. 1. General Summarv of 1975 76 Research Last year we presented an integral equation formulation of the ultrasonic scattering problem. We also compared the results of the Born approximation with exact results for spherical scatterers. From that study we learned much about the regions of applicability and validity of the Born approximation. In this year's research we have continued the theoretical workl, but placed special emphasis on attempts to make contact with the experimental situ~ tion for laboratory flaws prepared at Rockwell in determined geometries (a step closer to the \"real world\" In particular, we tried to identify some general features or indices that might be useful in evaluation of scattering data for NOT. In the course of many fruitful interactions with the experimental groups at Rockwell and Tennessee we learned about the needs and the formats most convenient for them, and developed a library of computer programs for various scattering situations. We have also investigated further approximations (static, quasi static) which may be better in certain limits, and started to compute and compare them with exact and experimental data. Finaliy, we h;;ve begun work to implement scattering theory for defects other than holes or inclusions, particularly scattering by flat cracks. We proceed with details of the studies. I I. Indices for NDT We have considered scattering by defects of two shapes, spheroids and cylinders, to seek information that indicates the deviat1on of the scatterer from spherical symmetry. The geometry of both scatterers can be characterized by a ratio b/a (see Fig. 1)", "author_names": [ "James A Krumhansl", "Eytan Domany", "P Musikar", "Stephen Teitel", "David Wood" ], "corpus_id": 26665245, "doc_id": "26665245", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Interpretation of Ultrasonic Scattering Measurements by Various Flaws from Theoretical Studies", "venue": "", "year": 1977 } ]
nonlocal density functional approximation for
[ { "abstract": "Using the weighted density approximation for the exchange correlation energy, the band structure and bulk structural properties of the prototypical semiconductors Si and Ge have been systematically studied. The weighted density approximation is based on an improved description of the exchange correlation hole that explicitly accounts for the inhomogeneous charge density found in real materials. We find that the approximation as proposed is inadequate for the case of semiconductors where charge inhomogeneity is intimately connected to a gap in the excitation spectrum with consequent qualitative changes in screening. We use a simple extension of the weighted density approximation which takes account of semiconductor screening. With this functional, we find substantial improvement in the calculated minimum gap over the results of the usual local density approximation as compared to experiment. However, the direct gaps are not significantly improved. Calculated structural properties are, moreover, found to be in excellent agreement with experiment. By way of contrast, the weighted density approximation implemented with metallic screening gives a smaller change in the band structure and more importantly, substantially poorer calculated structural properties. A discussion of the qualitative differences between the weighted density approximation and the usual local density approximation for covalently bonded semiconductors is presented.", "author_names": [ "Mark S Hybertsen", "Steven G Louie" ], "corpus_id": 121665019, "doc_id": "121665019", "n_citations": 43, "n_key_citations": 0, "score": 1, "title": "Nonlocal density functional approximation for exchange and correlation in semiconductors", "venue": "", "year": 1984 }, { "abstract": "In this paper we formulate a nonlocal density functional theory of inhomogeneous water. We model a water molecule as a couple of oppositely charged sites. The negatively charged sites interact with each other through the Lennard Jones potential (steric and dispersion interactions) square well potential (short range specific interactions due to electron charge transfer) and Coulomb potential, whereas the positively charged sites interact with all types of sites by applying the Coulomb potential only. Taking into account the nonlocal packing effects via the fundamental measure theory (FMT) dispersion and specific interactions in the mean field approximation, and electrostatic interactions at the many body level through the random phase approximation, we describe the liquid vapour interface. We demonstrate that our model without explicit account of the association of water molecules due to hydrogen bonding and with explicit account of the many body electrostatic interactions at the many body level is able to describe the liquid vapour coexistence curve and the surface tension at the ambient pressures and temperatures. We obtain very good agreement with available in the literature MD simulation results for density profile of liquid vapour interface at ambient state parameters. The formulated theory can be used as a theoretical background for describing of the capillary phenomena, occurring in micro and mesoporous materials.", "author_names": [ "Yu A Budkov", "Andrei L Kolesnikov" ], "corpus_id": 214693283, "doc_id": "214693283", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Nonlocal density functional theory of water taking into account many body dipole correlations: Binodal and surface tension of 'liquid vapour' interface.", "venue": "Journal of physics. Condensed matter an Institute of Physics journal", "year": 2020 }, { "abstract": "", "author_names": [ "Yuan Gao", "Wenguang Zhu", "Xinguo Ren" ], "corpus_id": 213379936, "doc_id": "213379936", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Long range behavior of a nonlocal correlation energy density functional based on the random phase approximation", "venue": "", "year": 2020 }, { "abstract": "Despite the large number of nonlocal kinetic energy density functionals (KEDFs) available for large scale calculation of extended systems, these KEDFs based on the Lindhard response function, in many cases, are not suitable for the isolated systems, where deviate from the uniform electron gas scenario. In this manuscript, we proposed a generalized scheme to construct nonlocal KEDFs via the local density approximated kernel. This scheme can significantly improve the accuracy and generality of orbital free density functional theory (OFDFT) to handle the isolated systems. We have implemented it into our developed ATLAS package under Dirichlet boundary condition and demonstrated the superior computational performances by several prototypical systems encompassing Mg, Si and GaAs clusters. The results show that the KEDFs constructed by our scheme can achieve high accuracy and numerical stability for simulations of isolated systems, applicable to design clusters and quantum dots containing a large number of atoms.", "author_names": [ "Qiang Xu", "Jian Lv", "Yanchao Wang", "Yanming Ma" ], "corpus_id": 201670085, "doc_id": "201670085", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Construction of Nonlocal Kinetic Energy Density Functional via Local Density Approximation Kernel for Isolated Systems", "venue": "", "year": 2019 }, { "abstract": "We construct a free energy density functional approximation for the primitive model of the electrical double layer. The hard sphere term of the free energy functional is based on a nonlocal generic model functional proposed by Percus. This latter model functional, which is a generalization of the exact solution for the nonuniform hard rod model, requires as input the free energy of a homogeneous hard sphere mixture. We choose the extension of the Carnahan Starling equation of state to mixtures. The electrostatic part of the nonuniform fluid ion ion correlations present in the interface is approximated by that of a homogeneous bulk electrolyte. Using the mean spherical approximation for a neutral electrolyte, we apply the theory to symmetrical 1:1 and 2:2 salts in the restricted primitive model. We present comparisons of density profiles and diffuse layer potentials with Gouy Chapman theory and Monte Carlo data. We also compare our results with data from other recent theories of the double layer. For highl.", "author_names": [ "Luis Mier-Y-Teran", "Soong Hyuck Suh", "Henry S White", "H Ted Davis" ], "corpus_id": 54815379, "doc_id": "54815379", "n_citations": 103, "n_key_citations": 0, "score": 0, "title": "A nonlocal free energy density functional approximation for the electrical double layer", "venue": "", "year": 1990 }, { "abstract": "Abstract We use three gradient level and two nonlocal density functional approximations to study the thermodynamic properties of Cu Au compounds. It is found that a well designed gradient level approximation (quasi non uniform approximation, QNA) reproduces the experimental equilibrium volumes and the formation energies of L12 and L10 phases. On the other hand, QNA predicts a non existent b2 phase, which can be remedied only when employing the nonlocal hybrid level Heyd Scuseria Ernzerhof (HSE06) or Perdew Burke Ernzerhof (PBE0) approximations. Gradient level approximations lead to similar electronic structures for the Cu Au compounds whereas hybrids shift the d band towards negative energies and account for the complex d d hybridization more accurately.", "author_names": [ "Liyun Tian", "Kalevi Kokko", "Levente Vitos" ], "corpus_id": 52569297, "doc_id": "52569297", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Gradient level and nonlocal density functional descriptions of Cu Au intermetallic compounds", "venue": "", "year": 2018 }, { "abstract": "By invoking a divide and conquer strategy, subsystem DFT dramatically reduces the computational cost of large scale, ab initio electronic structure simulations of molecules and materials. The central ingredient setting subsystem DFT apart from Kohn Sham DFT is the non additive kinetic energy functional (NAKE) Currently employed NAKEs are at most semilocal (i.e. they only depend on the electron density and its gradient) and as a result of this approximation, so far large scale simulations only included systems composed of weakly interacting subsystems. In this work, we advance the state of the art by introducing fully nonlocal NAKEs in subsystem DFT simulations for the first time. A benchmark analysis based on the S22 5 test set shows that nonlocal NAKEs considerably improve the computed interaction energies and electron densities compared to commonly employed GGA NAKEs, especially when increasing inter subsystem electron density overlap is considered. Most importantly, we resolve the long standing problem of too attractive interaction energy curves typically resulting from the use of GGA NAKEs.", "author_names": [ "Wenhui Mi", "Michele Pavanello" ], "corpus_id": 207780157, "doc_id": "207780157", "n_citations": 12, "n_key_citations": 1, "score": 0, "title": "Nonlocal Subsystem Density Functional Theory.", "venue": "The journal of physical chemistry letters", "year": 2019 }, { "abstract": "Despite a large number of nonlocal kinetic energy density functionals (KEDFs) available for large scale calculations, most of those nonlocal KEDFs designed for the extended systems cannot be directly applied to isolated systems. In this manuscript, we proposed a generalized scheme to construct nonlocal KEDFs via the local density approximation kernels and construct a family of KEDFs for simulations of isolated systems within orbital free density functional theory. The performance of KEDFs has been demonstrated by several clusters encompassing Mg, Si and GaAs. The results show that our constructed KEDFs can achieve high numerical accuracy and stability for random clusters, therefore, making orbital free density functional theory accessible for practical simulations of isolated systems.", "author_names": [ "Qiang Xu", "Jian Lv", "Yanchao Wang", "Yanming Ma" ], "corpus_id": 213230336, "doc_id": "213230336", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Nonlocal kinetic energy density functionals for isolated systems obtained via local density approximation kernels", "venue": "", "year": 2020 }, { "abstract": "A 10 parameter, range separated hybrid (RSH) generalized gradient approximation (GGA) density functional with nonlocal correlation (VV10) is presented. Instead of truncating the B97 type power series inhomogeneity correction factors (ICF) for the exchange, same spin correlation, and opposite spin correlation functionals uniformly, all 16,383 combinations of the linear parameters up to fourth order (m 4) are considered. These functionals are individually fit to a training set and the resulting parameters are validated on a primary test set in order to identify the 3 optimal ICF expansions. Through this procedure, it is discovered that the functional that performs best on the training and primary test sets has 7 linear parameters, with 3 additional nonlinear parameters from range separation and nonlocal correlation. The resulting density functional, oB97X V, is further assessed on a secondary test set, the parallel displaced coronene dimer, as well as several geometry datasets. Furthermore, the basis set dependence and integration grid sensitivity of oB97X V are analyzed and documented in order to facilitate the use of the functional.", "author_names": [ "Narbe Mardirossian", "Martin Head-Gordon" ], "corpus_id": 3007367, "doc_id": "3007367", "n_citations": 305, "n_key_citations": 5, "score": 0, "title": "oB97X V: a 10 parameter, range separated hybrid, generalized gradient approximation density functional with nonlocal correlation, designed by a survival of the fittest strategy.", "venue": "Physical chemistry chemical physics PCCP", "year": 2014 }, { "abstract": "Orbital Free Density Functional Theory (OF DFT) promises to describe the electronic structure of very large quantum systems, being its computational cost linear with the system size. However, the OF DFT accuracy strongly depends on the approximation made for the kinetic energy (KE) functional. To date, the most accurate KE functionals are non local functionals based on the linear response kernel of the homogeneous electron gas, i.e. the jellium model. Here, we use the linear response kernel of the jellium with gap model, to construct a simple non local KE functional (named KGAP) which depends on the band gap energy. In the limit of vanishing energy gap (i.e. in the case of metals) the KGAP is equivalent to the Smargiassi Madden (SM) functional, which is accurate for metals. For a series of semiconductors (with different energy gaps) the KGAP performs much better than SM, and results are close to the state of the art functionals with complicated density dependent kernels.", "author_names": [ "Lucian A Constantin", "Eduardo Fabiano", "Fabio Della Sala" ], "corpus_id": 119185845, "doc_id": "119185845", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Nonlocal kinetic energy functional from the jellium with gap model: Applications to orbital free density functional theory", "venue": "", "year": 2018 } ]
Silicon wafer thinning, the singulation process, and die strength
[ { "abstract": "In recent years, the realization of the IoT (Internet of Things) society, in which anyone can connect to the network to search for anything at anytime from anywhere, is approaching. For the IoT to progress, semiconductor devices (chips) such as various types of sensors and communication and memory devices, manufactured by forming a circuit on the silicon wafer, are essential. In general, both \"thinning\" and \"minimizing\" are required. On the other hand, die strength improvement is also very important for improving the yield of the manufacturing process and enhancing the endurance of the final product. This review explains the die strength of the CMP and DP stress relief wafer thinning processes and the DBG singulation process.", "author_names": [], "corpus_id": 211249471, "doc_id": "211249471", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Silicon wafer thinning, the singulation process, and die strength", "venue": "", "year": 2016 }, { "abstract": "Abstract In this paper, we have studied the characteristics of silicon dice, singulated using a high power high repetition rate femtosecond laser. The die strength and surface roughness, of the die side walls, are evaluated for different laser parameters such as pulsewidth and repetition rate. Since, the 80 mm thick wafers used in this study were polished on both sides, die edge roughness plays a decisive factor in determining the die strength when compared to backside roughness and wafer thickness as is the case in other studies. Excellent side wall average surface roughness of 0.35 mm is obtained at pulsewidth of 214 fs and repetition rate of 4.33 MHz using an average laser power of 15.5 W. Die strength is measured via the 3 point bending test. Strength reduction, due to die side wall surface defects that are induced through the wafer dicing process, is evaluated through die strength and surface roughness analysis. Die strength of a silicon dice is characterized as the first step in prediction and prevention of die failure during the package assembly, reliability test and working life. Improvement in the die side wall surface roughness is observed with the usage of nitrogen gas assist as compared to that obtained in air.", "author_names": [ "Nitin Sudani", "Krishnan Venkatakrishnan", "Bo Tan" ], "corpus_id": 119477913, "doc_id": "119477913", "n_citations": 35, "n_key_citations": 0, "score": 0, "title": "Laser singulation of thin wafer: Die strength and surface roughness analysis of 80 mm silicon dice", "venue": "", "year": 2009 }, { "abstract": "Driven by the ever growing desire for more compact electronic devices, the semiconductor industry has moved toward thinner silicon wafers. Simultaneously, the semiconductor industry has introduced new and better materials to facilitate the size shrinking. These factors introduce serious limitation in current saw blade semiconductor wafer dicing technology and needs new processing tools. Although nanosecond laser dicing overcomes most of the issues related to saw blade dicing, the dicing throughput remains below the current industrial requirement. In this paper a novel dual focus mechanism is introduced to increase the throughput of laser wafer dicing. Experimental results proved that dual focus increases the dicing speed, reduces the kerf width, eliminates the debris and enhances the die fracture strength. Cutting strategy and laser parameters, such as back focus power, repetition rate and wavelength, that influence the machining efficiency and quality, were studied in detail. The industrial implement of laser singulation is discussed.", "author_names": [ "Krishnan Venkatakrishnan", "Bo Tan" ], "corpus_id": 111065216, "doc_id": "111065216", "n_citations": 22, "n_key_citations": 1, "score": 0, "title": "Thin silicon wafer dicing with a dual focused laser beam", "venue": "", "year": 2007 }, { "abstract": "Current mechanical wafer dicing process adopting diamond grit shows advantages of low cost and high productivity. However, mechanical process for ultra thin wafers would induce residual stress or mechanical damage, which can lead to wafer broken and die cracking. With the development of laser technology, laser precision micromachining has been employed for thin semiconductor wafer singulation, which shows advantages of no chipping, small kerf width, and high throughput over mechanical blade dicing. However, thermal damage to the chip induced by laser ablation results in die strength degradation. For ultra thin chip, low die strength tends to induce die crack in packaging process. Thus, thermal damage to the chip needs to be studied. In this study, first we made a comparison between mechanical blade sawing and laser ablation processes. Die strength and microstructure changes were studied by means of bending test and transmission electron microscope (TEM) analysis, respectively. Die strength results showed that the die strength obtained by laser dicing was far lower than that obtained by blade sawing. TEM analysis demonstrated that formation of microcracks and porosities in laser diced face, caused the die strength degradation. In addition, significant deviation between frontside and backside die strength was found in the laser micromachinned dies. The reason for this deviation was clarified as the defects density difference existing in top and bottom layer of the chip sidewalk Experiments results showed that the die strength obtained by laser dicing can not meet the demand of the packaging process. It tends to crack or fracture in the die attach or wire bonding process. Thus, it is essential to improve the die strength. Thus, in this investigation, etching processes including wet etch and dry etch were attempted to recover the die strength by removing the chip side wall damage. SEM and TEM images indicated that, before etching, the laser diced side walls were with rough surfaces, voids and microcracks. After etching, the surfaces got smooth and most of the voids and microcracks were removed. Chip strength measurement also verified the partial die strength recovery after etching process.", "author_names": [ "Jianhua Li", "Hyeon Hwang", "Eunchul Ahn", "Qiang Chen", "Pyoung-Wan Kim", "Teakhoon Lee", "Myeongkee Chung", "Taegyeong Chung" ], "corpus_id": 8617229, "doc_id": "8617229", "n_citations": 36, "n_key_citations": 1, "score": 0, "title": "Laser Dicing and Subsequent Die Strength Enhancement Technologies for Ultra thin Wafer", "venue": "2007 Proceedings 57th Electronic Components and Technology Conference", "year": 2007 }, { "abstract": "As semiconductor based devices are manufactured on ever thinner silicon substrates, the required associated die break strength has to increase commensurately to maintain pick yields. In this study, the influence of laser processing parameters on the die break strength in laser dicing of silicon oxide coated silicon wafers and silicon based memory devices is investigated experimentally using ultraviolet lasers spanning a wide range of pulse width, from 400 fs to 150 ns. It is found that the net fluence, an accumulated pulse energy per surface area, is a meaningful process metric for damage induced by heat affect zone to compare lasers processes with a large variety of pulse widths, laser scan speed, average powers, and repetition rates. Optimized process conditions for both nanosecond and femtosecond pulse widths are identified for achieving the highest die break strength in the target devices. The dependence of heat affected zone on pulse width and net fluence during nanosecond laser processing is further.", "author_names": [ "D Finn", "Zhibin Lin", "Jan Kleinert", "Michael Darwin", "Haibin Zhang" ], "corpus_id": 109920145, "doc_id": "109920145", "n_citations": 23, "n_key_citations": 1, "score": 0, "title": "Study of die break strength and heat affected zone for laser processing of thin silicon wafers", "venue": "", "year": 2015 }, { "abstract": "Let us have a look at the main spheres for silicon chips: The processors you find in your PCs, memory chips used in nearly every electronic module, the power devices your car is full of and the smart labels found in access cards, tickets and labeling applications which make our daily life easier. For each of these applications the chips are going thin. What is the driving force of this development, why are we going thin? For processors the main advantage of thin substrates is improved heat dissipation. Stacking of memory chips needs also thin silicon. For power devices it is reduction in electrical resistance. For smart cards and related applications the main feature is the flexibility of thin silicon, which makes the IC chip capable of surviving daily use. The question is: what are the mechanical properties after thinning and chip singulation? What are their root causes? We have done investigations to find and evaluate causes of the mechanical damage in thin chips. We begin with a search for the stability necessary for a safe and reliable handling of the chips. We demonstrate the resulting threshold for chip stability and some processes to reach this limit. In a next step we show the influence of chip separation technologies. Influences to the chip side wall can result in mechanical damage or change stability. Our paper shows results regarding back side hardness and also the differences in mechanical properties between blank chips and processed devices. We present results of our investigations regarding dicing quality and influences to the product chips. Especially the resulting side wall surface of the chips is characteristic for the separating technology applied. Looking at silicon from a material point of view it is hard, stable and brittle. Thus the wafers made of silicon show certain fragility. Especially during wafer thinning, the wafers are stressed mechanically. The reduced stability on wafer level is one of the reasons for wafer breakage. But for back end processes and product applications the stability on chip level is of more importance. Pre Assembly is showing the major influence on mechanical properties of silicon chips. The two main process groups here are wafer thinning and chip separation. Also in final applications stresses, coming from e.g. temperature changes, have to be balanced by excellent mechanical performance. Besides the features needed for the chip applications, chip stability is also necessary for the process chain from chip separation to packaging. We did investigations in dicing quality looking at kerf width, residues, side wall damage and chip stability. As a result we can judge the different root causes influencing chip damage and stability", "author_names": [ "W Kroninger", "Franco Mariani" ], "corpus_id": 25618339, "doc_id": "25618339", "n_citations": 29, "n_key_citations": 1, "score": 0, "title": "Thinning and singulation of silicon: root causes of the damage in thin chips", "venue": "56th Electronic Components and Technology Conference 2006", "year": 2006 }, { "abstract": "Singulation can be the most damaging step in electronic manufacturing where individual dice are freed from a brittle silicon wafer. So much torque and force is applied to the silicon during this process that if precautionary steps are not taken, the freed die may exhibit low strength due to chipping damage. For medical devices, this is particularly a problem because medical devices must be specially shaped and assembled so that they can fit into small implantable or insertable units for the human body. Insertable medical products require that dice have unusually high aspect ratios in order to fit into tubular shaped instruments. For this paper, we have emulated a medical device using blank silicon wafers cut to >3.60 mm long 0.36 mm wide and 0.100 mm thick. The aspect ratios of 10:1 will be compared with lower as well as high aspect ratios for dicing quality and die integrity. With standard dicing parameters with standard blades, the singulation yield would be as low as zero. Even the use of step cut which in most cases would alleviate chipping, but for such high aspect ratio dice, the yield improved to only 50% This paper will present comparative yield results of various dicing setups to find the process with the best yield on singulated dice. 100% yield for singulation resulting in higher strength devices can be obtained using properly selected blades with the correct dicing parameters. Newer, stronger and narrower blades are allowing dice with high aspect ratios to be sawn without chipping yield loss. Also special dicing programs are required to produce chip free dies without resorting to laser saws.", "author_names": [ "Annette Teng", "Finn Wilhelmsen" ], "corpus_id": 12817501, "doc_id": "12817501", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Medical Device Wafer Singulation", "venue": "2007 32nd IEEE/CPMT International Electronic Manufacturing Technology Symposium", "year": 2007 }, { "abstract": "In support of improved productivity for the semiconductor and optoelectronics manufacturing industry, new work is presented on the development of a plasma based die singulation process technique for thin Si wafers. It is shown that the technique leads to a significant gain in productivity through reduced process times and increased available good die per wafer. Some additional related key benefits are increased yield, die strength, and the potential of nonorthogonal die.", "author_names": [ "Kenneth D Mackenzie", "David Pays-Volard", "Linnell Martinez", "Chris W Johnson", "Thierry Lazerand", "Russell Westerman" ], "corpus_id": 8159975, "doc_id": "8159975", "n_citations": 3, "n_key_citations": 1, "score": 0, "title": "Plasma based die singulation processing technology", "venue": "2014 IEEE 64th Electronic Components and Technology Conference (ECTC)", "year": 2014 }, { "abstract": "Plasma Dicing uses Deep Reactive Ion Etch (DRIE) also known as The Bosch Process. This is a well established \"front end\" technology, used in silicon MEMS micromachining and via etching in 3D packaging, which is now finding a new home as a dicing technology in the \"back end\" of semiconductor processing. This paper will discuss the key issues and integration challenges. This is not only in wafer design and preparation, but also how the process flow is not disrupted to the extent where it becomes a hindrance to the adoption of a technology that offers so many potential benefits.", "author_names": [ "Richard Barnett" ], "corpus_id": 614695, "doc_id": "614695", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Plasma Dicing 300mm Framed Wafers Analysis of Improvement in Die Strength and Cost Benefits for Thin Die Singulation", "venue": "2017 IEEE 67th Electronic Components and Technology Conference (ECTC)", "year": 2017 }, { "abstract": "Thin silicon die (100 um or less) are required for a number of applications, including stacked die packages and three dimensional integrated circuits (3D IC) The wafer thinning process is conceptually simple, but requires optimization of the backside finish and dicing to ensure high die strength. High die strength is required to minimize yield loss during assembly and to ensure high reliability during device operation. In this paper, we describe process optimization for thin wafers and thin die, and how these processes affect the fracture strength of silicon.", "author_names": [ "Jeff P Gambino" ], "corpus_id": 17292346, "doc_id": "17292346", "n_citations": 13, "n_key_citations": 1, "score": 0, "title": "Thin silicon wafer processing and strength characterization", "venue": "Proceedings of the 20th IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA)", "year": 2013 } ]
Advances in Electronics and Electron Physics
[ { "abstract": "Digital techniques in electron off axis holography, G. Ade optical symbolic substitution architectures, M.S. Alam and M.A. Karim semiconductor quantum devices, M. Cahay and S. Bandyopadhyay fuzzy relations and applications, B. de Baets and E. Kerre basis algorithms in mathematical morphology, R. Jones and I.D. Svalbe mirror bank energy analyzers, S.P. Karetskaya et al.", "author_names": [ "Ladislaus Laszlo Marton", "Robert L Sproull" ], "corpus_id": 121947651, "doc_id": "121947651", "n_citations": 2026, "n_key_citations": 24, "score": 1, "title": "Advances in Electronics and Electron Physics", "venue": "", "year": 1958 }, { "abstract": "", "author_names": [ "Mario Bertero" ], "corpus_id": 116311390, "doc_id": "116311390", "n_citations": 136, "n_key_citations": 16, "score": 0, "title": "Advances in Electronics and Electron Physics", "venue": "", "year": 1989 }, { "abstract": "", "author_names": [ "" ], "corpus_id": 107999666, "doc_id": "107999666", "n_citations": 119, "n_key_citations": 9, "score": 0, "title": "Advances in electronics and electron physics", "venue": "", "year": 1990 }, { "abstract": "", "author_names": [ "P H Batey" ], "corpus_id": 120407312, "doc_id": "120407312", "n_citations": 41, "n_key_citations": 2, "score": 0, "title": "Advances in Electronics and Electron Physics", "venue": "", "year": 1973 }, { "abstract": "", "author_names": [ "A H W Beck" ], "corpus_id": 109471419, "doc_id": "109471419", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Advances in Electronics and Electron Physics", "venue": "", "year": 1970 }, { "abstract": "", "author_names": [ "Laurence J Marton" ], "corpus_id": 120382959, "doc_id": "120382959", "n_citations": 47, "n_key_citations": 0, "score": 0, "title": "Advances in Electronics and Electron Physics. Vol.30", "venue": "", "year": 1955 }, { "abstract": "", "author_names": [ "Matthias Nussbaum" ], "corpus_id": 124825001, "doc_id": "124825001", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Acoustic Imaging With Electronic Circuits Advances In Electronics And Electron Physics Volume 11", "venue": "", "year": 2016 }, { "abstract": "The Free Electron Laser (FEL) principle has been known since the early 1970's but for many years FEL's have played a marginal role in comparison with conventional lasers. Only in recent years it has become clear that these devices have the potential of becoming exceedingly powerful light sources in the vacuum ultraviolet (VUV) and X ray regime. In my talk I will first deal with undulator radiation since it is intimitely related to FEL radiation, then explain the low gain FEL and finally treat the highgain FEL based on the principle of Self Amplified Spontaneous Emission (SASE) SASE FEL's are frequently considered as the fourth generation of accelerator based light sources. In contrast to existing synchrotron radiation light sources which are mostly storage rings the FEL requirements on the electron beam quality in terms of low transverse emittance and small energy spread are so demanding that only linear accelerators can be used to provide the drive beam. In my one hour talk it was not possible to go much into mathematical details. The high gain FEL is therefore treated only qualitatively. For a thorough presentation of SASE FEL's I refer to the book \"The Physics of Free Electron Lasers\" by Saldin, Schneidmiller and Yurkov and to the lectures by J. Rossbach at the CERN Accelerator School on Synchrotron Radiation.", "author_names": [ "N Andersen" ], "corpus_id": 55884399, "doc_id": "55884399", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Free electron lasers: Charles A. Brau. Advances in Electronics and Electron Physics, Supplement 22 (Academic Press, Boston, 1990) pp. xi 420, softbound, US $39.95, ISBN 0 12 126000 3", "venue": "", "year": 1991 }, { "abstract": "Edited by L. Marton New York and London: Academic Press Inc. Pp. x 341. Price 11.00 This latest edition of Advances in Electronics includes six survey papers entitled The Electron as a Chemical Entity, Problems of Photoconductivity, Strong Focusing Lenses, Hydrogen Thyratrons, Cerenkov Radiation at Microwave Frequencies, and High Power Axial Beam Tubes. More than one third of the book is given to Strong Focusing Lenses, by which is meant electron lenses consisting of 4 poles (or electrodes) arranged like the 4 poles of the stator of a d.c. machine and providing a magnetic (or electric) field which has constant radial gradient H/r (or E/r)", "author_names": [ "M R Gavin" ], "corpus_id": 125327783, "doc_id": "125327783", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Advances in Electronics and Electron Physics, Volume XIV", "venue": "", "year": 1961 }, { "abstract": "", "author_names": [ "Zhong Cun Chun Er" ], "corpus_id": 117697269, "doc_id": "117697269", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Advances in Electronics and Electron Physics, Vol. 18, Academic Press. 1963, 342Ye 15x23cm, 5,000Yuan", "venue": "", "year": 1964 } ]
Asymmetric electric field screening in van der Waals heterostructures
[ { "abstract": "A long standing challenge facing the combination of two dimensional crystals into heterojunction is the unknown effect of mixing layer of different electronic properties (semiconductors, metals, insulators) on the screening features of the fabricated device platforms including their functionality. Here we use a compelling set of theoretical and experimental techniques to elucidate the intrinsic dielectric screening properties of heterostructures formed by MoS2 and graphene layers. We experimentally observed an asymmetric field screening effect relative to the polarization of the applied gate bias into the surface. Surprisingly, such behavior allows selection of the electronic states that screen external fields, and it can be enhanced with increasing of the number of layers of the semiconducting MoS2 rather than the semi metal. This work not only provides unique insights on the screening properties of a vast amount of heterojunction fabricated so far, but also uncovers the great potential of controlling a fundamental property for device applications.Charge density reorganization at the interface between 2D materials may lead to electric field screening. Here, the authors investigate the dielectric screening properties of MoS2/graphene van der Waals heterostructures and identify an asymmetric electric response under different directions of the applied electric field.", "author_names": [ "Luhua Li", "Tian Tian", "Qiran Cai", "Chih-Jen Shih", "Elton J G Santos" ], "corpus_id": 4398326, "doc_id": "4398326", "n_citations": 21, "n_key_citations": 0, "score": 1, "title": "Asymmetric electric field screening in van der Waals heterostructures", "venue": "Nature Communications", "year": 2018 }, { "abstract": "We investigated the electronic properties of bilayer van der Waals heterostructures consisting of MoS2 and WS2 under an external electric field using the density functional theory with the effective screening medium method. Our calculation shows that carrier accumulation in the heterostructures strongly depends on the mutual arrangement of MoS2 and WS2 with respect to the counter electrode. We further demonstrate that carrier accumulation also depends on the carrier species, biaxial strain, and interlayer stacking arrangement because of the band alignment near the band gap attributed to interlayer orbital hybridization.", "author_names": [ "Mina Maruyama", "Susumu Okada" ], "corpus_id": 195387597, "doc_id": "195387597", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Asymmetric carrier accumulation in van der Waals heterostructures of MoS2/WS2 under an external electric field", "venue": "Applied Physics Express", "year": 2019 }, { "abstract": "Since the discovery of graphene, a broad range of two dimensional (2D) materials has captured the attention of the scientific communities. Materials, such as hexagonal boron nitride (hBN) and the transition metal dichalcogenides (TMDs) family, have shown promising semiconducting and insulating properties that are very appealing for the semiconductor industry. Recently, the possibility of taking advantage of the properties of 2D based heterostructures has been investigated for low power nanoelectronic applications. In this work, we aim at evaluating the relation between the nature of the materials used in such heterostructures and the amplitude of the layer to layer charge transfer induced by an external electric field, as is typically present in nanoelectronic gated devices. A broad range of combinations of TMDs, graphene, and hBN has been investigated using density functional theory. Our results show that the electric field induced charge transfer strongly depends on the nature of the 2D materials used in the van der Waals heterostructures and to a lesser extent on the relative orientation of the materials in the structure. Our findings contribute to the building of the fundamental understanding required to engineer electrostatically the doping of 2D materials and to establish the factors that drive the charge transfer mechanisms in electron tunneling based devices. These are key ingredients for the development of 2D based nanoelectronic devices.", "author_names": [ "A H Lu", "Michel Houssa", "Iuliana P Radu", "Geoffrey Pourtois" ], "corpus_id": 5279285, "doc_id": "5279285", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Toward an Understanding of the Electric Field Induced Electrostatic Doping in van der Waals Heterostructures: A First Principles Study.", "venue": "ACS applied materials interfaces", "year": 2017 }, { "abstract": "The discovery of two dimensional (2D) ferroic materials has stimulated substantial efforts in developing emergent functionalities by synthesizing van der Waals (vdW) heterostructures, and one promising effect is the nonvolatile electrical control of magnetism in magnetoelectric (ME) heterostructures consisting of coupled 2D vdW ferromagnetic and ferroelectric layers. In this paper, it is proposed that the asymmetric interfacial coupling in such heterostructures may seriously distort the ferroelectric double well potential, thus destabilizing the ferroelectricity. We investigate this consequence in \\mathrm{F}\\mathrm{e}}_{3}\\mathrm{GeT}\\mathrm{e}}_{2}\\ensuremath{\\alpha}\\ensuremath{ \\mathrm{I}\\mathrm{n}}_{2}\\mathrm{S}\\mathrm{e}}_{3} vdW heterostructure using the first principles calculations. It is revealed that one of the two potential wells for ferroelectric monolayer \\ensuremath{\\alpha}\\ensuremath{ \\mathrm{I}\\mathrm{n}}_{2}\\mathrm{S}\\mathrm{e}}_{3} is suppressed by the asymmetric interfacial coupling between electric polarization and the built in electric field induced by intrinsic charge transfer, while the ferroelectric bistability can be recovered when the \\ensuremath{\\alpha}\\ensuremath{ \\mathrm{I}\\mathrm{n}}_{2}\\mathrm{S}\\mathrm{e}}_{3} layer is thicker than three unit cells. Therefore, this work presents an alternative mechanism of critical thickness for the 2D ferroelectricity in ME vdW heterostructures.", "author_names": [ "Xiaokun Huang", "Guannan Li", "Changfeng Chen", "Xin Nie", "Xiang-ping Jiang", "Jun-ming Liu" ], "corpus_id": 213776516, "doc_id": "213776516", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Interfacial coupling induced critical thickness for the ferroelectric bistability of two dimensional ferromagnet/ferroelectric van der Waals heterostructures", "venue": "", "year": 2019 }, { "abstract": "Controlling the half metallicity of 2D magnets is of great significance for both fundamental research and potential applications in quantum information storage, transmission and processing. Among the possible 2D magnetic heterostructures, those with intrinsic magneto electric coupling have a great potential in this field. Herein we theoretically investigate the experimentally feasible CrI3 CrGeTe3heterobilayers (Cr H) and show electric field dependent half metallicity. Besides the stacking dependent magnetization in Cr H, robust half metallicity can be induced in ferromagnetic and ferrimagnetic heterobilayers by an electric field over 0.6 V A 1. This is due to the electric controlled band alignment in such asymmetric band structure. Furthermore, a spin polarized band crossing is introduced in its type II spin channel for a continuously increased electric field. Thus, the magnetic heterobilayer (e.g.Cr H) with spin polarized band alignment represents a promising materials platform for the design of 2D controllable magnetoelectronic and spintronic devices.", "author_names": [ "Cheng Tang", "Lei Zhang", "Stefano Sanvito", "Aijun Du" ], "corpus_id": 219006458, "doc_id": "219006458", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Electric controlled half metallicity in magnetic van der Waals heterobilayer", "venue": "", "year": 2020 }, { "abstract": "The dielectric screening is one of the most fundamental properties of 2D materials which is used to characterize electronic properties such as storage capacity of charge or energy. We numerically investigate three potential heterostructures of MoS2 Graphene and their corresponding interlayer interactions. Applying a density functional approach to the lowest energy structure of the interlayer, we find that, within a lower field regime 10 MV/cm) the dielectric constant is independent of the vertical electric field and dependent of the interlayer distance and stacking pattern of heterostructures composed of MoS2 and Graphene. From the calculation results of the induced charge throughout the heterostructure, we find how the van der Waals interaction influences the dielectric constant.", "author_names": [ "Ashutosh Kumar Singh", "Seunghan Lee", "Hoonkyung Lee", "Hiroshi Watanabe" ], "corpus_id": 227232881, "doc_id": "227232881", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Dielectric Constant and van der Waals Interlayer Interaction of MoS2 Graphene Heterostructures", "venue": "2020 IEEE 15th International Conference on Nano/Micro Engineered and Molecular System (NEMS)", "year": 2020 }, { "abstract": "We systematically explore the electronic and transport properties of Graphene CrBr$_{3} heterolayer based on \\emph{ab initio} density functional theory simulations. Our result shows the modulation in electronic band gap with applied electric field variation from 0.5 to +0.5 V/\\AA} The electric field variation marked linear and non linear trend for band gap modulation due to polarization effects between the two layers. It is found that the transmission at the interface is spin polarized upto 71.2\\ and the magnetic moment is found to be invariant. Moreover, complex band structure and transmission spectrum reveals the possibilities of spin transmission in Graphene CrBr$_{3} heterostructure via magnetic proximity effect. The merits of electric field tunability and magnetic proximity effect in this 2D layered ferromagnetic semiconductor heterostructure will be beneficial to extend its suitability in spintronics device applications.", "author_names": [ "Sushant Kumar Behera", "Mayuri Bora", "Sapta Sindhu Paul Chowdhury", "Pritam Deb" ], "corpus_id": 195767039, "doc_id": "195767039", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Magnetic proximity effect and electric field modulation in Graphene CrBr$_{3} van der Waals heterostructure", "venue": "", "year": 2019 }, { "abstract": "Monolayer MoS2 is a direct band gap semiconductor with large exciton binding energy, which is a promising candidate for the application of ultrathin optoelectronic devices. However, the optoelectronic performance of monolayer MoS2 is seriously limited to its growth quality and carrier mobility. In this work, we report the direct vapor growth and the optoelectronic device of vertically stacked MoS2/MoSe2 heterostructure, and further discuss the mechanism of improved device performance. The optical and high resolution atomic characterizations demonstrate that the heterostructure interface is of high quality without atomic alloying. Electrical transport measurements indicate that the heterostructure transistor exhibits a high mobility of 28.5 cm2/(V*s) and a high on/off ratio of 107. The optoelectronic characterizations prove that the heterostructure device presents an enhanced photoresponsivity of 36 A/W and a remarkable detectivity of 4.8 x 1011 Jones, which benefited from the interface induced built in electric field and carrier dependent Coulomb screening effect. This work demonstrates that the construction of two dimensional (2D) semiconductor heterostructures plays a significant role in modifying the optoelectronic device properties of 2D materials.", "author_names": [ "Fang Li", "Boyi Xu", "Wen Yang", "Zhaoyang Qi", "Chao Ma", "Yajuan Wang", "Xuehong Zhang", "Zhuoran Luo", "Delang Liang", "Dong Li", "Ziwei Li", "Anlian Pan" ], "corpus_id": 215775075, "doc_id": "215775075", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "High performance optoelectronic devices based on van der Waals vertical MoS2/MoSe2 heterostructures", "venue": "Nano Research", "year": 2020 }, { "abstract": "Combining van der Waals heterostructures by stacking different two dimensional materials on top of each other layer by layer can enhance their desired properties and greatly extend the applications of the parent materials. In this work, by means of first principles calculations, we investigate systematically the structural and electronic properties of six different stacking configurations of a Si/GaSe heterostructure. The effect of biaxial strain and electric field on the electronic properties of the most energetically stable configuration of the Si/GaSe heterostructure has also been discussed. At the equilibrium state, the electronic properties of the Si/GaSe heterostructure in all its stacking configurations are well kept as compared with that of single layers owing to their weak van der Waals interactions. Interestingly, we find that a sizable band gap is opened at the Dirac K point of silicene in the Si/GaSe heterostructure, which could be further controlled by biaxial strain or electric field. These findings open up a possibility for designing silicene based electronic devices, which exhibit a controllable band gap. Furthermore, the Si/GaSe heterostructure forms an n type Schottky contact with a small Schottky barrier height of 0.23 eV. A transformation from the n type Schottky contact to a p type one, or from the Schottky contact to an ohmic contact may occur in the Si/GaSe heterostructure when strain or an electric field is applied.", "author_names": [ "P T T Le", "Nguyen Ngoc Hieu", "Le Minh Bui", "Huynh V Phuc", "Bui D Hoi", "Bin Amin", "Chuong Van Nguyen" ], "corpus_id": 53229512, "doc_id": "53229512", "n_citations": 49, "n_key_citations": 0, "score": 0, "title": "Structural and electronic properties of a van der Waals heterostructure based on silicene and gallium selenide: effect of strain and electric field.", "venue": "Physical chemistry chemical physics PCCP", "year": 2018 }, { "abstract": "Indium Selenide (In2Se3) is a newly emerged van der Waals (vdW) ferroelectric material, which unlike traditional insulating ferroelectric materials, is a semiconductor with a bandgap of about 1.36 eV. Ferroelectric diodes and transistors based on In2Se3 have been demonstrated. However, the interplay between light and electric polarization in In2Se3 has not been explored. In this paper, we found that the polarization in In2Se3 can be programmed by optical stimuli, due to its semiconducting nature, where the photo generated carriers in In2Se3 can alter the screening field and lead to polarization reversal. Utilizing these unique properties of In2Se3, we demonstrated a new type of multifunctional device based on 2D heterostructures, which can concurrently serve as a logic gate, photodetector, electronic memory and photonic memory. This dual electrical and optical operation of the memories can simplify the device architecture and offer additional functionalities, such as ultrafast optical erase of large memory arrays. In addition, we show that dual gate structure can address the partial switching problem commonly observed in In2Se3 ferroelectric transistors, as the two gates can enhance the vertical electric field and facilitate the polarization switching in the semiconducting In2Se3. These discovered effects are of general nature and should be observable in any ferroelectric semiconductor. These findings deepen the understanding of polarization switching and light polarization interaction in semiconducting ferroelectric materials and open up their applications in multifunctional electronic and photonic devices.", "author_names": [ "Kai Xu", "Weiman Jiang", "Xueshi Gao", "Zijing Zhao", "Tony Low", "Wenjuan Zhu" ], "corpus_id": 227080234, "doc_id": "227080234", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Optical control of ferroelectric switching and multifunctional devices based on van der Waals ferroelectric semiconductors.", "venue": "Nanoscale", "year": 2020 } ]
ACS Photonics 5（9），3472-3477（2018）
[ { "abstract": "Two dimensional (2D) materials such as graphene, transition metal dichalcogenides (TMDs) and hexagonal boron nitride (hBN) have attracted a large amount of interests due to their extraordinary electrical, optical, and mechanical properties comparing with their bulk counterparts. Recently, black phosphorus (BP) has emerged as a new 2D material with demonstrated high hole mobility, showing great potential in electronic applications such as field effect transistors (FETs) In this talk we will first review our recent works on the electric, photo electrical, mechanical, and thermal behaviors of few layer black phosphorus [1 4] We will then discuss the photonics applications of black phosphorus. 2D black phosphorus is an excellent candidate for use in photodetection devices due to its direct and thickness dependent bandgap [1] However, light absorptions in these 2D materials are often very low due to its ultra thin nature. For example, the visible light absorption in single layer graphene is only 2.3% Making plasmonic structures, such as nano disks and rods, on top of the 2D material can be a possible way to enhance the absorption. In our work, a new bowtie like plasmonic structure was proposed, and numerical simulations were used to design and optimize the plasmonic structures that are used to enhance both absorption and polarization selectivity in black phosphorus photodetection devices. The optimized structure devices were then fabricated on black phosphorus on transparent substrate. Photocurrent measurements showed strong light polarization dependence/selectivity in the fabricated device as well as much stronger photo responsivity compared with devices without plasmonic enhancement. Our study demonstrated the potentials of black phosphorus for photodetection and other light harvesting applications. [1] Liu, H. Neal, A. Zhu, Z. Luo, Z. Xu, X. Tomanek, D. Ye, P.D. 2014, \"Phosphorene: An Unexplored 2D Semiconductor with a High Hole Mobility,\" ACS Nano, 8(4) pp. 4033 4041. [2] Deng, Y. Luo, Z. Conrad, N. J. Liu, H. Gon,g Y. Najmaei, S. Ajayan, P. M. Lou, J. Xu, X. and Ye, P. D. 2014, \"Black Phosphorus Monolayer MoS2 van der Waals Heterojunction P N Diode.\" ACS Nano, 8(8) pp. 8292 8299. [3] Luo, Z. Maassen, J. Deng, Y. Du, Y. Garrelts, R. P. Lundstrom, M. S. Ye, P. D. and Xu, X. 2015, \"Anisotropic in plane thermal conductivity observed in few layer black phosphorus\" Nat. Commun. 6:8572, pp. 9572 1 8. [4] Du, Y. Maassen, J. Wu, W. Luo, Z. Xu, X. and Ye, P. 2016, \"Auxetic Black Phosphorus: A 2D Material with Negative Poisson's Ratio\" Nano Lett. DOI: 10.1021/acs.nanolett.6b03607.", "author_names": [ "Xianfan Xu" ], "corpus_id": 139879016, "doc_id": "139879016", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Black phosphorus: a novel 2D material and its photonics applications (Conference Presentation)", "venue": "", "year": 2018 }, { "abstract": "W read with great interest the article \"Enantioselective Optical Trapping of Chiral Nanoparticles with Plasmonic Tweezers\" by Yang Zhao and collaborators, which appeared in ACS Photonics in 2016. The authors expand the idea of chiral forces, which act differently on the enantiomers of a chiral substance, to propose an enantioselective optical trap. They theoretically analyzed such a trap based on a specifically designed plasmonic nanostructure and found that it traps only one enantiomer of a given chiral substance while repelling the other. Obviously, such a device would be highly interesting, especially for chemistry and pharmaceutics. However, we believe that there are severe difficulties for actual realizations of this effect, which we will discuss in this comment. The total trapping force acting on the molecule is given as (cf. eq 3 in ref 1)", "author_names": [ "Martin Schaferling", "Harald Giessen" ], "corpus_id": 125415181, "doc_id": "125415181", "n_citations": 4, "n_key_citations": 0, "score": 1, "title": "Comment on \"Enantioselective Optical Trapping of Chiral Nanoparticles with Plasmonic Tweezers\"", "venue": "", "year": 2018 }, { "abstract": "The potential of supramolecular transition metal coordination complexes to form robust, long living, radiative charge transfer states makes this class of triplet state emitters ideal candidates for application as photosensitizes or in photonic devices. Antenna enhanced phosphorescence experiments on single Ru2+ bis terpyridine complexes incorporated into a thin PMMA film show that phosphorescence emission spectra can exhibit shifts depending on the local environment [J. F. Herrmann, P. S. Popp, A. Winter, U. S. Schubert and C. Hoppener, ACS Photonics, 2016, 3, 1897 1906] Here, we demonstrate that the environmentally altered spectral properties of individual dual luminescent Ru2+ bis terpyridine complexes in PMMA and acetonitrile can be reproduced by DFT based vibrationally resolved Franck Condon spectra, if the phosphorescent emission of different molecular conformations is taken into account. Furthermore, we demonstrate that the triplet emission of these complexes occurs from a metal to ligand charge transfer (MLCT) state.", "author_names": [ "Tobias Koch", "Christiane Hoppener", "Nikos L Doltsinis" ], "corpus_id": 52308528, "doc_id": "52308528", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Conformation dependent phosphorescence emission of individual mononuclear ruthenium (ii) bis terpyridine complexes.", "venue": "Physical chemistry chemical physics PCCP", "year": 2018 }, { "abstract": "Thickness is one of the most important parameters in many applications using thin layers. This article describes determination of the thickness of boron doped nanocrystalline diamond (NCD) grown on fused silica glass. The spectroscopic measurement system has been used. A high refractive index (2.3 550 nm) was achieved for NCD films. The thickness of the NCD samples has been determined from transmission spectrum. Full Text: PDF References Z. Li, S. Butun, K. Aydin, 'Large area, lithography free super absorbers and color filters at visible frequencies using ultrathin metallic films' ACS Photonics, vol. 2.2, pp. 183 188 2015. CrossRef L. Yu, D.D. Tune, C.J. Shearer, J.G. Shapter, 'Implementation of antireflection layers for improved efficiency of carbon nanotube silicon heterojunction solar cells' Solar Energy, vol. 118, pp. 592 599, 2015. CrossRef D. Majchrowicz, Daria, et al. Nitrogen Doped Diamond Film for Optical Investigation of Hemoglobin Concentration, Materials, vol. 11.1, pp. 109, 2018. CrossRef K.L. Konnerth, F.H. Dill, 'In situ measurement of dielectric thickness during etching or developing processes' IEEE Transactions on Electron Devices, vol. 22.7, pp. 452 456, 1975. CrossRef Z.G. Hu, P. Prunici, P. Hess, K.H. Chen, 'Optical properties of nanocrystalline diamond films from mid infrared to ultraviolet using reflectometry and ellipsometry' Journal of Materials Science: Materials in Electronics, vol. 18.1, pp. 37 41, 2007. CrossRef J. Adamczewska, et al. 'Procesy technologiczne w elektronice polprzewodnikowej' WNT, Warsaw, 1980. J.P. Dilger, L. R. Fisher, D. A. Haydon, 'A critical comparison of electrical and optical methods for bilayer thickness determination' Chemistry and Physics of Lipids, vol. 30.2 3, pp. 159 176, 1982. CrossRef M, Ficek, et al, 'Optical and electrical properties of boron doped diamond thin conductive films deposited on fused silica glass substrates' Applied Surface Science, vol. 387, pp. 846 856, 2016. CrossRef R. Bogdanowicz, et al, 'Opto Electrochemical Sensing Device Based on Long Period Grating Coated with Boron Doped Diamond Thin Film' J. Opt. Soc. Korea, vol. 19, pp. 705 710, 2015. CrossRef M. Sobaszek, et al. 'Optical and electrical properties of ultrathin transparent nanocrystalline boron doped diamond electrodes' Optical Materials, vol.42, pp. 24 34, 2015. CrossRef R. Bogdanowicz, et al, 'Improved surface coverage of an optical fibre with nanocrystalline diamond by the application of dip coating seeding' Diamond and Related Materials, vol. 55, pp. 52 63, 2015. CrossRef Z.G. Hu, P. Hess, 'Optical constants and thermo optic coefficients of nanocrystalline diamond films at 30 500oC' Applied physics letters, vol. 89.8: 081906, 2006. CrossRef", "author_names": [ "Aleksandra Wieloszynska", "Robert Bogdanowicz" ], "corpus_id": 125340382, "doc_id": "125340382", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Studies on optical transmittance of boron doped nanocrystalline diamond films", "venue": "", "year": 2018 }, { "abstract": "We thank you for a terrific week of nano in Boston at the fall American Chemical Society meeting! The editors of ACS Nano, our advisory board, and our authors were instrumental in putting together programs on advances in nanoscience and nanotechnology and how these are impacting other fields. We had sessions on nano in energy harvesting and storage, neuroscience, photonics, space, sustainability, three dimensional (3D) printing, tissue engineering, and more. We also had sessions, talks, and events on science communications and support for nanoscience and nanotechnology in the United States and around world, topics that are closely intertwined. One of the key takeaways is that we need to communicate what the contributions of nanoscience and nanotechnology are and will be to our colleagues, to the public, and to government leaders around the world. Since there are few devices, materials, or objects that are \"purely nano\" it is important for us to highlight what is \"nano enabled.\" Nano Day is coming up on October 9 (10 9) which will be a good reminder for all of us to start and to continue this outreach. In Los Angeles, we will once again be getting together to celebrate (ironically) at 1 Pico, in Santa Monica. If you are in town, please join us. If you are elsewhere, let us know what you are doing and where you will be meeting. On December 3 of this year, we will celebrate the 15th anniversary of the signing of the U.S. Nanotechnology Research and Development Act, which put into law the National Nanotechnology Initiative (NNI) programs and activities that continue to this day and that catalyzed nanoscience and nanotechnology research around the world. Stay tuned for more on how we will recognize this anniversary.", "author_names": [ "Paul S Weiss" ], "corpus_id": 52814910, "doc_id": "52814910", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Nano in Boston and Beyond.", "venue": "ACS nano", "year": 2018 }, { "abstract": "Engineering the wavefront of light in random media allows the control of wave propagation in space and time by exploiting the spatial and spectral degrees of freedom introduced by multiple scattering (M. Mounaix et al, Phys. Rev. Lett. 116, 253901 (2016) To apply this far field control strategy and focus electromagnetic energy at the nanoscale, it is necessary to introduce scatterers that feature strongly enhanced and confined optical fields such as plasmonic nanoantennas. In particular, semi continuous gold films close to the percolation threshold feature high local field enhancements (S. Gresillon et al, Phys. Rev. Lett. 82, 4520 (1999) but also propagating surface plasmon waves that can be controlled using a spatial light modulator (P. Bondareff et al, ACS Photonics 2, 1658 (2015) In this presentation, we demonstrate how controlling the phase of an incoming pulsed laser on a chosen 10 um x 10 um area of a random plasmonic metasurface allows us to optimize the two photon luminescence (TPL) of gold at a given position of the sample. The optimized TPL intensities, that are associated with strong local field enhancements, are increased by a factor of 50 for semi continuous films that are close to percolation compared to samples far from it, demonstrating that the morphology and randomness of the plasmonic film play an essential role in the control of nonlinear luminescence. Furthermore, we show that TPL intensities can be enhanced at any position of a percolated film, opening exciting perspectives for the wavefront engineering of local field enhancements in random plasmonic metasurfaces.", "author_names": [ "Gauthier Roubaud", "Pierre Bondareff", "Giorgio Volpe", "Sebastien Bidault", "Sylvain Gigan", "Samuel Gresillon" ], "corpus_id": 126281504, "doc_id": "126281504", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Local optimization of nonlinear luminescence in random gold metasurfaces by far field wavefront control (Conference Presentation)", "venue": "", "year": 2018 }, { "abstract": "Gao Xing Neng shirikonGuang Ji Ji Hui Lu noShi Xian woMu Zhi suShang deha, Duo Yang naCai Liao karanaruGuang Su Zi nohaiburitsudoJi Ji gaBi Yao to naru. koremadeuehaRong Zhao yaJie Jing Cheng Chang niyoruZhong \"noHua He Wu Ban Dao Ti Guang Yuan noshirikonShang Ji Ji gaYan Jiu saretekita[1] Zhong demoWei Xiao Guang Yuan noJi Ji haZhong Yao dearuga, Cong Lai noShou Fa dehahaiburitsudoJi Ban Shang denoGuang Yuan Jia Gong gaBi Yao deari, nano rezaDeng noJi Wei Xiao Gou Zao noZuo Zhi haRong Yi dehanakatsuta. Yi Fang Zhuan Xie purintoFa [2]ha, huanderuwarusuLi woJie shi tananoGou Zao noZhuan Xie gaKe Neng deari, Duo Yang nananoGou Zao woDu Li niJia Gong Hou shirikonJi Ban Shang hehaiburitsudoJi Ji surukoto gadekiru(Tu 1) Ben Fa Biao deha, Zhuan Xie purintoFa woYong itashirikonDao Bo Lu niJie He shitaLiang Zi dotsutonanorezanoShi Xian ni tsuiteBao Gao suru. Tu 2niZuo Zhi shitaGou Zao noGai Nian Tu woShi su. InAsLiang Zi dotsu towoNei Bao shitaGaAshuotonitsukuJie Jing nanobimuGong Zhen Qi ka ranaru 2 tsunonanorezaga, U Zi noshirikonDao Bo Lu nie banetsusentoJie He shiteiru. Shi Yan deha, Hou mi 370nmnoga rasuniMai meIp maretaDao Bo Lu noZhi Shang ni 2tsunonanoGong Zhen Qi rezawoShun Ci Zhuan Xie purintoshiJi Ji shita[Tu 3(a) konoShi Liao nitsuite, Bo Chang 808nmnoparusurezaLi Qi nomotoDi Wen Xian Wei Fen Guang Fa niyoruGuang Xue Ping Jia woXing tsuta. nanoGong Zhen Qi wo sorezoreLi Qi shi, Gong Zhen Qi Zhi Shang niteQu De shitasupekutoru woTu 3(b)Shang Bu niShi su. Guan Ce shitaGong Zhen Qi pikunitsuite, Li Qi Qiang Du Yi Cun Xing woDiao betatokoro, Chu Li noJi Ji naZeng Jia to Gong Zhen Qi Xian Fu noXia Zhai Hua gaGuan Ce sare, rezaFa Zhen gaQue Ren dekita. mata, Dao Bo Lu Liang Duan nogureteinguSu Zi karano Fang She woDiao betatokoro, Gong Zhen Qi Zhi Shang deGuan Ce saretamonoto Tong Yi noBo Chang niGong Zhen Qi pikugaGuan Ce sareta[Tu 3(b)Xia Bu Zi Ran Fang Chu niYou Lai surubatsukugurandogaYi Zhi sare, Gong Zhen Qi modonomigaChuan Ban shiteirukotogaFen karu. Yi Shang yo ri, shirikonDao Bo Lu niJie He shitaLiang Zi dotsutonanorezanoDong Zuo gaQue Ren sareta. Xie Ci Ben Yan Jiu haKe Yan Fei Te Bie Tui Jin Yan Jiu (15H05700) Ke Yan Fei Bu Zhu Jin (16K06924)Ji biNEDOpuroguramuniyoriSui Xing sareta. [1] B. Jang et al. Appl. Phys. Express 9, 092102 (2016) J. Kwoen et al. The 44th International Symposium on Compound Semiconductor (2017) S. Keyvaninia et al. Opt. Express 21, 3784, (2013) D. Liang and J. E. Bowers, Nat. Photonics 4, 511 (2010) [2] J. Yoon et al. Adv. Optical Mater. 3, 1313 (2015) [3] O. Painter et al. Science 284, 1819 (1999) [4] M. Khajavikhan et al. Nature 482, 204 (2012) [5] J. Lee et al. ACS Photonics 4, 2117 (2017) Fig.2 Schematic illustration of quantum dot nanolasers evanescently coupled to a silicon waveguide. Fig 1. Schematic representation of transfer printing.", "author_names": [ "Alto Osada", "Yasutomo Ota", "Ryota Katsumi", "Katsuyuki Watanabe", "Satoshi Iwamoto", "Yasuhiko Arakawa" ], "corpus_id": 139853237, "doc_id": "139853237", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Demonstration of quantum dot nanolasers coupled to a silicon waveguide by transfer printing", "venue": "", "year": 2018 }, { "abstract": "Data supporting the paper: Sun, K. Riedel, C. A. Urbani, A. Simeoni, M. Mengali, S. Zalkovskij, M. Muskens, O. L. (2018) VO 2 Thermochromic Metamaterial Based Smart Optical Solar Reflector. ACS Photonics. DOI: 10.1021/acsphotonics.8b00119", "author_names": [ "Kai Sun", "Christoph A Riedel", "Alessandro Urbani", "Mirko Simeoni", "Sandro Mengali", "Maksim Zalkovskij", "Brian Bilenberg", "C H De Groot", "Otto L Muskens" ], "corpus_id": 139810416, "doc_id": "139810416", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Dataset for VO2 thermo chromic metamaterial based smart optical solar reflector", "venue": "", "year": 2018 }, { "abstract": "Single layer metallic rings are the effective structure cell which are widely used to design single band and multiband perfect metamaterial absorbers owning to their electromagnetic resonance. However, the absorbers based on the single layer metallic rings have a common shortcoming, that is the narrow absorption bandwidth. To overcome the limitations, here we proposed a single layer, flexible and broadband terahertz metamaterial absorber, which consists of four sub cells with multiple metal rings and a metal ground plane separated by a dielectric layer. By enhancing the coupling response between adjacent metallic rings and merging the adjacent resonant peaks of multi resonators, we experimentally observed broadband characteristics at the terahertz band. The average absorption of 88% from 0.63 to 1.34 THz and the relative absorption bandwidth of 95% at the incident angle of 15o for TE polarization. Correspondingly, for TM polarization the absorption of more than 80% from 0.61 to 1.1 THz with the relative absorption bandwidth of 80% were also observed. The results went far beyond the previous single layer absorbers based on metal rings and were much better than the fractal cross structure reported recently [Kenney et al. ACS Photonics 4, 2604 (2017) We had reason to believe that the presented terahertz metamaterial absorber with broad absorption bandwidth and simple structure can find important applications in communication, stealth, energy harvesting systems and so on.Single layer metallic rings are the effective structure cell which are widely used to design single band and multiband perfect metamaterial absorbers owning to their electromagnetic resonance. However, the absorbers based on the single layer metallic rings have a common shortcoming, that is the narrow absorption bandwidth. To overcome the limitations, here we proposed a single layer, flexible and broadband terahertz metamaterial absorber, which consists of four sub cells with multiple metal rings and a metal ground plane separated by a dielectric layer. By enhancing the coupling response between adjacent metallic rings and merging the adjacent resonant peaks of multi resonators, we experimentally observed broadband characteristics at the terahertz band. The average absorption of 88% from 0.63 to 1.34 THz and the relative absorption bandwidth of 95% at the incident angle of 15o for TE polarization. Correspondingly, for TM polarization the absorption of more than 80% from 0.61 to 1.1 THz with the relative a.", "author_names": [ "Guoqing Shen", "Ming Zhang", "Yanping Ji", "Wanxia Huang", "Honglin Yu", "Jianping Shi" ], "corpus_id": 105654780, "doc_id": "105654780", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "Broadband terahertz metamaterial absorber based on simple multi ring structures", "venue": "", "year": 2018 }, { "abstract": "Efficient extraction of photons from quantum emitters is an important prerequisite for the use of such emitters in quantum optical applications as single photons sources or sensors. One way to achieve this is by coupling to a suited photonics structure, which guides away the emitter light. Here, we show the coupling of a single defect in hexagonal boron nitride (hBN) to a tapered optical fiber via a nanomanipulation technique [1] Defects in hBN are capable of emitting single photons at room temperature while being photostable at the same time two properties that make them ideal candidates for integration in single photon sources. The high control the manipulation technique provides avoids covering the whole nanofiber with emitters. We characterize the coupled system in terms of achievable count rates, saturation intensity, and spectral properties. Antibunching measurements are used to proof the single emitter nature of the defect. Our results pave the way for integration of single defects in hBN into photonic structure and their use as single photon sources in quantum optical applications such as quantum crypthography. [1] A W Schell et al. ACS Photonics, 4, 761 767 (2017)", "author_names": [ "Andreas W Schell", "Toan Trong Tran", "Hideaki Takashima", "Igor Aharonovich", "Shigeki Takeuchi" ], "corpus_id": 140053896, "doc_id": "140053896", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Single photon extraction from defects in hBN using a tapered fiber (Conference Presentation)", "venue": "", "year": 2018 } ]
FeFET ZrO2 seed layer
[ { "abstract": "Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub>(HZO) based ferroelectric field effect transistor (FeFET) with a ZrO<sub>2</sub> seed layer was demonstrated. It was found that the ZrO<sub>2</sub> seed layer could effectively improve the ferroelectric properties of the (hafnium zirconium oxide) HZO thin film. The remanent polarization and the coercive voltage of the metal ferroelectric insulator semiconductor (MFIS) structure with the ZrO<sub>2</sub> seed layer were larger than those without the seed layer. Moreover, the FeFET with the ZrO<sub>2</sub> seed layer showed wider counterclockwise hysteresis loops in the transfer characteristics than that without the seed layer, achieving a large memory window of about 2.8 V. These results validate the advantages of the ZrO<sub>2</sub> seed layer in promotion of FeFET performance and thus warrant further study.", "author_names": [ "Wenwu Xiao", "Chen Liu", "Yue Peng", "Shuaizhi Zheng", "Qian Feng", "Chunfu Zhang", "Jincheng Zhang", "Yue Hao", "Min Liao", "Yichun Zhou" ], "corpus_id": 108239121, "doc_id": "108239121", "n_citations": 27, "n_key_citations": 1, "score": 1, "title": "Performance Improvement of Hf0.5Zr0.5O2 Based Ferroelectric Field Effect Transistors With ZrO2 Seed Layers", "venue": "IEEE Electron Device Letters", "year": 2019 }, { "abstract": "The HfO2 based ferroelectric field effect transistor (FeFET) with a metal/ferroelectric/insulator/semiconductor (MFIS) gate stack is currently being considered as a possible candidate for high density and fast write speed non volatile memory. Although the retention performance of the HfO2 based FeFET with a MFIS gate stack could satisfy the requirements for practical applications, its memory window (MW) and reliability with respect to endurance should be further improved. This work investigates the advantage of employing ZrO2 seed layers on the MW, retention, and endurance of the Hf0.5Zr0.5O2 (HZO) based FeFETs with MFIS gate stacks, by using fast voltage pulse measurements. It is found that the HZO based FeFET with a ZrO2 seed layer shows a larger initial and 10 year extrapolated MW, as well as improved endurance performance compared with the HZO based FeFET without the ZrO2 seed layer. The results indicate that employing of a direct crystalline high k/Si gate stack would further improve the MW and reliability of the HfO2 based FeFETs.", "author_names": [ "Wenwu Xiao", "Chen Liu", "Yue Peng", "Shuaizhi Zheng", "Qian Feng", "Chunfu Zhang", "Jincheng Zhang", "Yue Hao", "Min Liao", "Yichun Zhou" ], "corpus_id": 198914851, "doc_id": "198914851", "n_citations": 19, "n_key_citations": 1, "score": 0, "title": "Memory Window and Endurance Improvement of Hf0.5Zr0.5O2 Based FeFETs with ZrO2 Seed Layers Characterized by Fast Voltage Pulse Measurements", "venue": "Nanoscale Research Letters", "year": 2019 }, { "abstract": "The effect of crystallized ZrO2 (ZrO2 seed) amorphous Hf0.43Zr0.57O2 (HZO; HZO seed) and amorphous Al2O3 (Al2O3 seed) seed layers on the ferroelectricity of HZO films was investigated. The remanent polarization of a TiN electroded capacitor with a ZrO2 seed layer was much larger than that of capacitors with a HZO seed, Al2O3 seed, or no seed layer. Furthermore, the maximum 2P r was exhibited when the thickness of the ZrO2 seed layer was 2 nm. Large grain growth was observed, which satisfied the same lattice pattern between ZrO2 and HZO films, and indicates that the ZrO2 seed layer plays an important role in the nucleation of the HZO film.", "author_names": [ "Takashi Onaya", "Toshihide Nabatame", "Naomi Sawamoto", "Akihiko Ohi", "Naoki Ikeda", "Toyohiro Chikyow", "Atsushi Ogura" ], "corpus_id": 103114972, "doc_id": "103114972", "n_citations": 25, "n_key_citations": 0, "score": 0, "title": "Improvement in ferroelectricity of Hf x Zr1 x O2 thin films using ZrO2 seed layer", "venue": "", "year": 2017 }, { "abstract": "", "author_names": [ "Onaya Takashi", "Nabatame Toshihide", "Sawamoto Naomi", "Ohi Akihiko", "Ikeda Naoki", "Chikyow Toyohiro", "Ogura Atsushi" ], "corpus_id": 197636591, "doc_id": "197636591", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Effect of ZrO2 seed layer on ferroelectricity of HfxZr1 xO2 thin film", "venue": "", "year": 2017 }, { "abstract": "Abstract Effects of Cr N ZrO 2 seed layer deposited on glass substrates before the deposition of C/Co Cr Pt/Cr Ti layers for longitudinal recording media have been investigated. The product of v and I s the activation volume and the saturation magnetization per unit volume, media noise N d and S 0 N d which is the half value of peak to peak output voltage of an isolated pulse over N d at 11.8 kFC/mm, are evaluated. We find that vI s is decreased by adding N and ZrO 2 to Cr seed layer. N d is reduced as vI s decreases by adding nitrogen to the Cr seed layer. This is mainly due to the decreased grain sizes of both Cr Ti underlayer and Co Cr Pt magnetic layer. The N d is further reduced by the addition of ZrO 2 to the Cr N seed layer. Highest S 0 N d is achieved for the media with Cr N ZrO 2 seed layer. On the other hand, the media with Cr ZrO 2 seed layer deposited without nitrogen show the higher N d Therefore the decrease of the grain size by addition of nitrogen into Ar is essential to reduce N d and the ZrO 2 addition to the Cr N seed layer seems to enhance the effect of grain size reduction by nitrogen addition.", "author_names": [ "Hiroyuki Suzuki", "David D Djayaprawira", "Yoshio Takahashi", "Akira Ishikawa", "Ono Toshinori", "Yotsuo Yahisa" ], "corpus_id": 122317729, "doc_id": "122317729", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Effects of Cr N ZrO2 seed layer formed on glass substrates for longitudinal recording media", "venue": "", "year": 1999 }, { "abstract": "We have experimentally demonstrated fully suspended nanowire (NW) gate all around (GAA) negative capacitance (NC) field effect transistors (FETs) with ultrasmall channel dimensions (5 nm \\times 12.5 $nm) they exhibit a remarkable \\mathrm{I}_{on} \\mathrm{I}_{off} ratio of over 1010. This work, for the first time, experimentally studies and compares the structures of metal ferroelectric metal insulator semiconductor (MFMIS) and metal ferroelectric insulator semiconductor (MFIS) NCFETs. The GAA with the MFMIS structure has a higher on state current owing to the metallic equal potential layer and superior S.S ._{min} of 39.22 mV/decade. A ZrO2 seed layer is inserted under HfZr $_{1 x} \\mathrm{O}_{x} HZO) to improve the ferroelectric crystallinity. Consequently, post metal annealing (PMA) the conventional crystallization annealing step, can be omitted in the presence of o phase. The gate current \\mathrm{I}_{G} is monitored to verify the multi domain HZO. A negative DIBL of 160 mV/V is observed because of the strong NC effect corresponding to previous simulated results.", "author_names": [ "Shen-Yang Lee", "Han-Wei Chen", "Chiuan-Huei Shen", "Po-Yi Kuo", "Chun-Chih Chung", "Yu-En Huang", "Hsin-Yu Chen", "Tien-Sheng Chao" ], "corpus_id": 199441598, "doc_id": "199441598", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Experimental Demonstration of Performance Enhancement of MFMIS and MFIS for 5 nm x 12.5 nm Poly Si Nanowire Gate All Around Negative Capacitance FETs Featuring Seed Layer and PMA Free Process", "venue": "2019 Silicon Nanoelectronics Workshop (SNW)", "year": 2019 }, { "abstract": "In this article, we successfully fabricated nanowire (NW) negative capacitance (NC) related ferroelectric FETs (FE FETs) with two structures: trigate (TG) and gate all around (GAA) Planar capacitors with a metal FE metal (MFM) structure were investigated first. Post metal annealing (PMA) at 700 degC resulted in the best ferroelectricity. This condition was considerably different from that of directly stacking onto NWs because of the difference in size and curvature between planar and TG or GAA structures. Because of the addition of an underlying ZrO<sub>2</sub> seed layer, Hf<inline formula> <tex math notation=\"LaTeX\"$_{{1} {x} /tex math>/inline formula>Zr<sub><italic>x</italic>/sub>O<sub>2</sub> in the gate stack has been crystallized before the PMA process. In addition, two different gate stack configurations, MFM insulator semiconductor (MFMIS) and metal FE insulator semiconductor (MFIS) were investigated for the GAA structure. We determined that MFMIS displayed considerably more favorable subthreshold behavior and ON state current compared with MFIS. NC related phenomena, such as negative drain induced barrier lowering and negative differential resistance, were observed.", "author_names": [ "Shen-Yang Lee", "Han-Wei Chen", "Chiuan-Huei Shen", "Po-Yi Kuo", "Chun-Chih Chung", "Yu-En Huang", "Hsin-Yu Chen", "Tien-Sheng Chao" ], "corpus_id": 210993124, "doc_id": "210993124", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Effect of Seed Layer on Gate All Around Poly Si Nanowire Negative Capacitance FETs With MFMIS and MFIS Structures: Planar Capacitors to 3 D FETs", "venue": "IEEE Transactions on Electron Devices", "year": 2020 }, { "abstract": "A stable substrate is extraordinarily important for the trace detection of Surface Enhanced Raman Scattering technique. We have designed in this paper a simple seed growth method to prepare Ag@ZrO2 core shell nanoparticles as well as regulate the core shell ratio by adjusted concentration of zirconium propoxides added. The shell thickness effect and spacing on SERS activities have been simulated in different finite time domains, which goes perfectly with those previous experiment results. With Ag@ZrO2 core shell nanoparticles adopted as the SERS substrate and R6G as molecular probe, the detection range could reach as great as 10 8 M. The regression model, obtained through principal component analysis, is adopted for some rapid and precise detection; and the determination coefficient (R2) is going up to 0.9743, proving that the SERS substrate we have prepared has extremely high detection accuracy. To explore the stability of core shell nanoparticles, we have taken both two different cases of strong acid solution as well as strong alkali solution for the core shell nanoparticle etching, and this is how a SERS test could be carried out. These experimental results have indicated that the outer zirconia layer could keep the silver surface from oxidation and its stability is ensured, quite crucial for the applied SERS.", "author_names": [ "Yong-Feng Zhou", "Pei Liang", "De Zhang", "Lisha Tang", "Qianmin Dong", "Shangzhong Jin", "Dejiang Ni", "Zhi Yu", "Jia-ming Ye" ], "corpus_id": 208298683, "doc_id": "208298683", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "A facile seed growth method to prepare stable Ag@ZrO2 core shell SERS substrate with high stability in extreme environments.", "venue": "Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy", "year": 2019 }, { "abstract": "For the first time, two layer stacked nanowire gate all around (GAA) negative capacitance (NC) field effect transistors (FETs) with an ultrasmall poly Si channel that has a size of <inline formula> <tex math notation=\"LaTeX\"$5.3\\times9$ /tex math>/inline formula> nm<sup>2</sup> and a metal ferroelectric metal insulator semiconductor (MFMIS) are experimentally demonstrated. FETs exhibit a remarkable I<sub>on</sub> I<sub>off</sub> ratio of more than 10<sup>8</sup> We demonstrated stacked channels, double layers, GAA NC FET with a threshold voltage <inline formula> <tex math notation=\"LaTeX\"{V}_{\\textit {TH} /tex math>/inline formula> of 0.61 V, and a superior subthreshold behavior with an average and minimum sub <inline formula> <tex math notation=\"LaTeX\"{V}_{\\textit {TH} /tex math>/inline formula> slope of 43.85 and 26.84 mV/dec, respectively. An additional ZrO<sub>2</sub> seed layer was inserted under the Hf<inline formula> <tex math notation=\"LaTeX\"$_{{1 {x} /tex math>/inline formula>Zr<sub>x</sub>O<sub>2</sub> layer to improve ferroelectric crystallinity. Thus, the conventional crystallization annealing step can be omitted due to the presence of the orthorhombic phase <inline formula> <tex math notation=\"LaTeX\"{o} /tex math>/inline formula> phase) before further post metal annealing (PMA)", "author_names": [ "Po-Yi Kuo", "Tien-Sheng Chao" ], "corpus_id": 203145963, "doc_id": "203145963", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Experimental Demonstration of Stacked Gate All Around Poly Si Nanowires Negative Capacitance FETs With Internal Gate Featuring Seed Layer and Free of Post Metal Annealing Process", "venue": "IEEE Electron Device Letters", "year": 2019 }, { "abstract": "Recently, the solution deposition planarization (SDP) technique for deposition of oxide layer for the IBAD MgO template has attracted more attentions. Although the texturing mechanism of IBAD MgO is still under debate, it is accepted that the seed layer (the one close to the MgO) should fulfill several requirements, such as atomic flatness surface as well as material composition. In this work, in order to clarify the influence of SDP seed layer materials on the texture of IBAD MgO layer, we chose Gd Zr O, Gd<sub>2</sub>O<sub>3</sub> ZrO<sub>2</sub> and Y <sub>2</sub>O<sub>3</sub> as seed layer materials. Atomic force microscopy (AFM) X ray diffractometer (XRD) and reflection high energy electron diffraction (RHEED) were used to illustrate the correlation between the microstructure of the seed layer and the texture of IBAD MgO film. AFM analysis shows that the atomic flatness was achieved on all the SDP films, as evidenced by the RMS value of around 0.3 nm on the 1 x 1 mm<sup>2</sup> grid area. RHEED results show that the poor texture of IBAD MgO is present when using Gd<sub>2</sub>O<sub>3</sub> and ZrO <sub>2</sub> as seed layer. Like Y<sub>2</sub>O<sub>3</sub> the SDP GZO film as a seed layer exhibits good compatibility with IBAD MgO. In addition, the XRD result on Gd Zr O xerogel powder implies that the films mainly consist of nanocrystalline Gd<sub>2</sub>Zr<sub>2</sub>O<sub>7</sub> which is a crucial feature of an efficient barrier layer. Eventually, a <italic>J</italic><sub>c</sub> value of 1.65 MA*cm<sup> 2</sup> (at 77 K, <italic>s.f./italic> was achieved on a full stack of YBCO/CeO<sub>2</sub>/IBAD MgO/SDP layer/C276 sample.", "author_names": [ "Jingyuan Chu", "Yue Zhao", "Shuiliang Zhen", "Guangyue Jiang", "Yongchun Chen", "Wei Wu", "Zhiwei Zhang", "Zhiyong Hong", "Zhijian Jin" ], "corpus_id": 3926299, "doc_id": "3926299", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Influence of Seed Layer Materials on the Texture of IBAD MgO Layer", "venue": "IEEE Transactions on Applied Superconductivity", "year": 2018 } ]
science diamond MOS
[ { "abstract": "Abstract A super high dielectric constant AlOx/TiOy nanolaminate film is grown on hydrogenated diamond (H diamond) to enable superior metal oxide semiconductor (MOS) capacitors and MOS field effect transistors (MOSFETs) In order to minimize or suppress leakage current, a nanometer thick AlOx film is inserted at the AlOx/TiOy nanolaminate/H diamond interface. The maximum values for the capacitance density and dielectric constant related to the summation of individual AlOx and nanolaminate are 1.06 mF/cm2 and 68.7, respectively. Capacitance density and dielectric constant for the AlOx/TiOy nanolaminate are as high as 5.22 mF/cm2 and 308, respectively. Electrical properties of four H diamond MOSFETs with gate lengths increasing from 2.4 mm to 10.1 mm were investigated. All of them showed p type behavior and distinct pinch off characteristics with drain current maxima of 47.4, 43.3, 26.6, and 24.6 mA/mm, respectively. On/off ratios and threshold voltages for the MOSFETs are higher than 104 and lower than 0.55 0.10 V, respectively. The low threshold voltages indicate that the AlOx/TiOy nanolaminate gate based MOSFETs can switch between ON and OFF stages at low gate voltages. Effective mobilities of the H diamond channel layers for all the MOSFETs raised firstly and dropped subsequently with increasing voltages, which can be explained by the effect of mobility limiting factors.", "author_names": [ "Jiangwei Liu", "Orlando Auciello", "Elida de Obaldia", "Bo Da", "Yasuo Koide" ], "corpus_id": 225146074, "doc_id": "225146074", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Science and Technology of Integrated Super High Dielectric Constant AlOx/TiOy Nanolaminates Diamond for MOS Capacitors and MOSFETs", "venue": "", "year": 2021 }, { "abstract": "Abstract Synchrotron based m XRF, m XAS and m XRD have made a major impact in the field of environmental science in the last ten years. One of the first seven 'day one' beamlines on the Diamond Light Source is a microfocus spectroscopy beamline, beamline I18. Here the current status of the beamline and the opportunities it presents in the field of environmental science are described, with results from two of the first experiments also included. The first is based on the use of bonemeal to remediate soil. We used Zn K edge and Pb L3 edge spectroscopy to characterize the speciation of these two elements on a soil after bonemeal treatment. The results are compared with bulk measurements taken on the whole soil and standard materials. The second experiment described here is a study of the speciation and association of Ni in a laterite from Moa Bay, Cuba. Here the differences in the Ni speciation associated with Mn oxides are examined and compared with Fe oxides phases.", "author_names": [ "J Frederick W Mosselmans", "Paul D Quinn", "Josep Roque Rosell", "Kirk D Atkinson", "Andrew J Dent", "S I Cavill", "Mark E Hodson", "Caroline Kirk", "Paul F Schofield" ], "corpus_id": 129255373, "doc_id": "129255373", "n_citations": 19, "n_key_citations": 0, "score": 0, "title": "The first environmental science experiments on the new microfocus spectroscopy beamline at Diamond", "venue": "Mineralogical Magazine", "year": 2008 }, { "abstract": "The electrical characteristics of metal semiconducting diamond (MS) metal insulating diamond semiconducting diamond (MiS) and metal oxide semiconducting diamond (MOS) structures on single crystal semiconducting diamond have been compared. Vertical structures were fabricated with the MS diode, MiS diode, and MOS capacitor on one face of the crystals and the ohmic contacts on the opposite face. Ohmic contacts, formed by ion implantation of B, exhibited reduced contact impedance. Current voltage and capacitance voltage characteristics of the three structures were measured. The MS and MiS diode structures exhibited large forward bias currents, whereas the insulating SiO2 limited the forward bias current through the MOSC structure. The MiS structure exhibited the lowest reverse bias leakage currents <10 pA/mm2) whereas the values for the MOSC and MS structures were 1 and 2 orders of magnitude larger, respectively. For all samples the uncompensated acceptor concentration of the semiconducting diamond was 1 2 X 1016 cm 3. These values were consistent with the secondary ion mass spectroscopy measurements of the B concentration in similar natural type IIb diamonds.", "author_names": [ "Michelle L Hartsell", "Henry A Wynands", "Bradley Alan Fox" ], "corpus_id": 137217853, "doc_id": "137217853", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Current voltage and capacitance voltage characterization of MS, MiS, and MOS structures on semiconducting diamond", "venue": "Photonics West Lasers and Applications in Science and Engineering", "year": 1994 }, { "abstract": "Peter Diamond is one of the major contributors to economics during the last half century. His many contributions include research on growth, Social Security, public finance more generally, the economics of uncertainty, search theory, in particular, and economic dynamics, in general. This work has shaped the way we think about many economic problems, and the way in which we formalize them. Among his long list of honors and awards, he is a fellow of the Econometric Society, a Guggenheim Fellow, a Fellow of the American Academy of Arts and Sciences, a Member of the National Academy of Sciences, and a Nemmers Prize winner. The National Science Foundation has supported his work for the last 40 years. A recent check indicated 9 books and 132 published articles, and there are few signs of any slowdown.", "author_names": [ "Giuseppe Moscarini", "Randall Wright" ], "corpus_id": 154666094, "doc_id": "154666094", "n_citations": 16, "n_key_citations": 4, "score": 0, "title": "AN INTERVIEW WITH PETER DIAMOND", "venue": "Macroeconomic Dynamics", "year": 2007 }, { "abstract": "Adding to the cross presentation family Immune responses to viral or tumor antigens are typically initiated by the process of cross presentation. Cross presentation is believed to be the major way that innate immune cells, such as the classical dendritic cell 1 (cDC1) subset, activate and prime immunological T cells. Theisen et al. used CRISPR based screening to identify regulators of cross presentation by cDC1s (see the Perspective by Barbet and Blander) One such regulator that was identified, WDFY4 (WD repeat and FYVE domain containing protein 4) was required for cross presentation of cell and bacterial associated antigens. WDFY4 played a critical role in cDC1 mediated viral and tumor immunity yet did not seem necessary for major histocompatibility complex class II presentation or for cross presentation by monocyte derived DCs. Science, this issue p. 694; see also p. 641 Dendritic cells require WDFY4 for cross presentation. During the process of cross presentation, viral or tumor derived antigens are presented to CD8+ T cells by Batf3 dependent CD8a+/XCR1+ classical dendritic cells (cDC1s) We designed a functional CRISPR screen for previously unknown regulators of cross presentation, and identified the BEACH domain containing protein WDFY4 as essential for cross presentation of cell associated antigens by cDC1s in mice. However, WDFY4 was not required for major histocompatibility complex class II presentation, nor for cross presentation by monocyte derived dendritic cells. In contrast to Batf3 mice, Wdfy4 mice displayed normal lymphoid and nonlymphoid cDC1 populations that produce interleukin 12 and protect against Toxoplasma gondii infection. However, similar to Batf3 mice, Wdfy4 mice failed to prime virus specific CD8+ T cells in vivo or induce tumor rejection, revealing a critical role for cross presentation in antiviral and antitumor immunity.", "author_names": [ "Derek J Theisen", "Jesse T Davidson", "Carlos G Briseno", "Marco Gargaro", "Elvin J Lauron", "Qiuling Wang", "Pritesh Desai", "Vivek Durai", "Prachi Bagadia", "Joshua R Brickner", "Wandy L Beatty", "Herbert W Virgin", "William E Gillanders", "Nima Mosammaparast", "Michael Steven Diamond", "L David Sibley", "Wayne M Yokoyama", "Robert D Schreiber", "Theresa L Murphy", "Kenneth M Murphy" ], "corpus_id": 53238366, "doc_id": "53238366", "n_citations": 93, "n_key_citations": 0, "score": 0, "title": "WDFY4 is required for cross presentation in response to viral and tumor antigens", "venue": "Science", "year": 2018 }, { "abstract": "Abstract The paper reviews publications, primarily of the Institute of Machinery Science of the Russian Academy of Sciences. The techniques of investigations and the results are briefly outlined as to how various high melting point materials withstand friction in vacuum and in gaseous atmospheres (within a wide temperature range) in like or unlike combinations, such as metals, metal like compounds, oxides, graphite materials and molybdenum disulphide. The results of measurements of adhesion, including that between diamond and various metals, are given. The friction drop of graphite material on corundum ceramics caused abnormally by tribochemical interaction, is described. The 'eutectic wear' accompanied by a sharp friction reduction is based on an investigation of the phenomenon of eutectic melting of diamond and graphite with experimental validation. The results of studies of vacuum ion plasma deposited CrO and MoS 2 coatings are demonstrated and a technique is suggested as to how to make the friction of MoS 2 very low.", "author_names": [ "Aleksandr P Semenov" ], "corpus_id": 137207999, "doc_id": "137207999", "n_citations": 30, "n_key_citations": 2, "score": 0, "title": "Tribology at high temperatures", "venue": "", "year": 1995 }, { "abstract": "Abstract The interface properties of Al2O3/hydrogen terminated diamond (H diamond) metal oxide semiconductor (MOS) structures both with and without NO2 p type doping were studied by measuring the capacitance voltage (C V) and conductance frequency (G f) characteristics to investigate the effect of NO2 p type doping at the Al2O3/H diamond interface. The interface state density was studied by measuring the conductance as a function of frequency and applied voltage. Interface state density (Dit) values are for NO2 p doped MOS structure varied from ~5.7 x 1012 cm 2 eV 1 at 0.27 eV above the valence band maximum (VBM) to 1.75 x 1012 cm 2 eV 1 at 0.36 eV above VBM. Conversely, MOS structure without NO2 p type doping exhibits a Dit value of approximately 4.2 x 1012 cm 2 eV 1 within an energy range of 0.27 to 0.39 eV. In addition, border trap density in the Al2O3 layer near the interface is also discussed.", "author_names": [ "Niloy Chandra Saha", "Makoto Kasu" ], "corpus_id": 139941371, "doc_id": "139941371", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Heterointerface properties of diamond MOS structures studied using capacitance voltage and conductance frequency measurements", "venue": "", "year": 2019 }, { "abstract": "Abstract By using Au as the gate metal contact, performance of NO2 doped H diamond field effect transistor (FET) has been improved. We fabricated and compared Al2O3 layer deposited, NO2 doped H diamond FETs with Au, Al and Ti gate metals, respectively. Among them, FET with Au gate metal showed the highest drain current of 61.76 mA/mm, where drain current of FET with Al and Ti gate metals were respectively 42.89 and 39.97 mA/mm. Further, NO2 doped metal oxide semiconductor (MOS) structures are fabricated and capacitance voltage measurements were performed to evaluate the effect of the metal work function and surface barrier height. This phenomenon has been explained in terms of surface barrier height of the Al2O3 layer and metal. Finally, band diagrams of MOS structures are simulated and determined. Band diagrams at various gate voltages are discussed.", "author_names": [ "Niloy Chandra Saha", "Makoto Kasu" ], "corpus_id": 139807791, "doc_id": "139807791", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Improvement of the Al2O3/NO2/H diamond MOS FET by using Au gate metal and its analysis", "venue": "Diamond and Related Materials", "year": 2019 }, { "abstract": "The electrical properties of Al2O3/p type diamond (111) MOS capacitors were studied with the goal of furthering diamond based semiconductor research. To confirm the formation of an inversion layer in the p type diamond body, an n type layer for use as a minority carrier injection layer was selectively deposited onto p type diamond. To form the diamond MOS capacitors, Al2O3 was deposited onto OH terminated diamond using atomic layer deposition. The MOS capacitor showed clear inversion capacitance at 10 Hz. The minority carrier injection from the n type layer reached the inversion n channel diamond MOS field effect transistor (MOSFET) Using the high low frequency capacitance method, the interface state density, D it, within an energy range of 0.1 0.5 eV from the valence band edge energy, E v, was estimated at (4 9) x 1012 cm 2 eV 1. However, the high D it near E v remains an obstacle to improving the field effect mobility for the inversion p channel diamond MOSFET.", "author_names": [ "Tsubasa Matsumoto", "H Kato", "Toshiharu Makino", "Masahiko Ogura", "Daisuke Takeuchi", "Satoshi Yamasaki", "Masataka Imura", "Akihiro Ueda", "Takao Inokuma", "Norio Tokuda" ], "corpus_id": 126205849, "doc_id": "126205849", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Direct observation of inversion capacitance in p type diamond MOS capacitors with an electron injection layer", "venue": "", "year": 2018 }, { "abstract": "This paper shows the effect of performing consecutive measurement prior to negative bias stress instability (NBSI) on diamond metal oxide semiconductor capacitor (MOSCAP) For the first time, time dependent stress tests have been carried out in order to investigate the stability of the flatband voltage <inline formula> <tex math notation=\"LaTeX\"{V}_{\\text {FB} /tex math>/inline formula> of MOSCAPs through capacitance voltage <italic>CV</italic> measurements. Two tests have been performed. In the first test, consecutive <italic>CV</italic> measurements with the device biased from deep depletion to the accumulation regime were performed to monitor the recovery of the <inline formula> <tex math notation=\"LaTeX\"{V}_{\\text {FB} /tex math>/inline formula> In the second test, NBSI technique has been applied. <inline formula> <tex math notation=\"LaTeX\"{V}_{\\text {FB} /tex math>/inline formula> stability has been measured by means of a time dependent bias stress in which the device was polarized at a fixed negative voltage for a specific time interval prior to performing the next <italic>CV</italic> measurement. As <inline formula> <tex math notation=\"LaTeX\"{V}_{\\text {FB} /tex math>/inline formula> is directly connected to the effective oxide charge <inline formula> <tex math notation=\"LaTeX\"{N}_{\\text {eff} /tex math>/inline formula> the two different tests allowed the extraction of total amount of <inline formula> <tex math notation=\"LaTeX\"{N}_{\\text {eff} /tex math>/inline formula> that interfered during the measurements. The result observed shows that the postoxidation annealing process induces a strong enhancement of the MOSCAP stability together with a decrease of <inline formula> <tex math notation=\"LaTeX\"{N}_{\\text {eff} /tex math>/inline formula>", "author_names": [ "O Loto", "Matthieu Florentin", "Cedric Masante", "Nazareno Donato", "Marie-Laure Hicks", "Alexander C Pakpour-Tabrizi", "Richard B Jackman", "Verena Zuerbig", "Phillippe Godignon", "David Eon", "Julien Pernot", "Florin Udrea", "Etienne Gheeraert" ], "corpus_id": 50770578, "doc_id": "50770578", "n_citations": 7, "n_key_citations": 1, "score": 0, "title": "Gate Oxide Electrical Stability of p type Diamond MOS Capacitors", "venue": "IEEE Transactions on Electron Devices", "year": 2018 } ]
FPGA Based Digital Magnetic Field Detection System
[ { "abstract": "This paper presents a digital magnetic field detection system, which can collect and analyze the remote sensing data by using the analog to digital converters (ADCs) The proposed digital magnetic field detection system contains two different types of digital pulse width modulation (PWM) ADCs by using the complementary metal oxide semiconductor (C MOS) mixed signal technology and the field programmable gate array platform (FPGA) The 12 bit digital PWM delta sigma \\Delta\\Sigma$ ADC is implemented in 180nm CMOS mixed signal technology and achieves the signal to noise distortion ratio (SNDR) the spurious free dynamic range (SFDR) and the effective number of bits (ENOB) are 70.68dB, 92.62dB and 11.44 bit with a supply voltage of 1.2V and at a sampling rate of 58.82kS/s. The digital PWM successive approximation register (SAR) ADC is based on FPGA to reduce the interference in the workpiece magnetic field to enhance reliability. Proposed digital PWM ADCs can be combined with a Hall effect sensor to measure the magnitude of a magnetic field without using the microcontroller, which are widely used for proximity sensing, positioning, speed detection, and current sensing applications.", "author_names": [ "Hua Fan", "Jingxuan Yang", "Jia Zhang", "Kelin Zhang", "Dezhi Xing", "Quanyuan Feng" ], "corpus_id": 231975791, "doc_id": "231975791", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "FPGA Based Digital Magnetic Field Detection System", "venue": "IGARSS 2020 2020 IEEE International Geoscience and Remote Sensing Symposium", "year": 2020 }, { "abstract": "Transcranial magnetic stimulation (TMS) a popular technology, acts on the brain by using a pulse magnetic field to cause a series of physiological and biochemical reactions. In order to detect the magnetic field generated by the TMS coil with high speed and multi channel performance, a novel magnetic field detection system based on a field programmable gate array (FPGA) is designed and implemented. The detection system includes an induction coil array, a data acquisition (DAQ) card, and upper computer monitor software. The DAQ card contains analog signal processing circuits, a multiplexer, an analog to digital converter, and a FPGA with a high speed, parallel, and switching idea. The system can sample at a rate of 500 ksps, with 14 bit resolution and 12 channels. The three dimensional (3D) magnetic field can be monitored on the screen with a waveform display and 3D magnetic field vector display. The DAQ card has a good signal noise and distortion and cross talk of 88.35 dB and 79.69 dB, respectively. Compared with the NI DAQ card, the proposed system has a relative error smaller than 1.81% and a mean square error smaller than 2.89 x 10 6, which verifies that the proposed detection system has a good performance. The multi channel high speed magnetic field detection system provides an important platform for the study of TMS in medical, engineering, and other fields.", "author_names": [ "Hui Xiong", "Chunhou Zheng", "Jin-Zhen Liu" ], "corpus_id": 49649661, "doc_id": "49649661", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "A multi channel high speed magnetic field detection system based on FPGA for transcranial magnetic stimulation.", "venue": "The Review of scientific instruments", "year": 2018 }, { "abstract": "We describe the development and implementation of a multifunction digital receiver suitable for magnetic resonance imaging with capability of real time frequency detection and compensation. The digital receiver consists primarily of firmware modules that combine the functionalities of signal acquisition, frequency detection and compensation, and data correction and image reconstruction. The receiver was developed based on a single multiple input multiple output radio frequency electronic board equipped with a reconfigurable Field Programmable Gate Array (FPGA) device. A simple and practical algorithm was developed and implemented on the FPGA to accelerate the data processing for frequency determination. The simplified frequency detection and the higher system integration enable the receiver to reduce dramatically the time for frequency detection and compensation. With this receiver, we are able to detect the frequency of short duration signals in the bandwidth of 10 MHz centered at 400 MHz within 75 ns after the signal acquisition. We describe the designs of the key FPGA modules and how these modules integrate into a multifunction receiver. We also present testing data that validate the simplified algorithm for frequency determination, demonstrate frequency detection and compensation, and demonstrate how real time data correction is performed during image acquisition and reconstruction.", "author_names": [ "Limin Li", "Alice M Wyrwicz" ], "corpus_id": 173995532, "doc_id": "173995532", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A multifunction digital receiver suitable for real time frequency detection and compensation in fast magnetic resonance imaging.", "venue": "The Review of scientific instruments", "year": 2019 }, { "abstract": "During operation of present fusion devices, the plasma facing components (PFCs) are exposed to high heat fluxes. Understanding and preventing overheating of these components during long pulse discharges is a crucial safety issue for future devices like ITER. Infrared digital cameras interfaced with complex optical systems have become a routine diagnostic to measure surface temperatures in many magnetic fusion devices. Due to the complexity of the observed scenes and the large amount of data produced, the use of high computational performance hardware for real time image processing is then mandatory to avoid PFC damages. At Tore Supra, we have recently made a major upgrade of our real time infrared image acquisition and processing board by the use of a new field programmable gate array (FPGA) optimized for image processing. This paper describes the new possibilities offered by this board in terms of image calibration and image interpretation (abnormal thermal events detection) compared to the previous system.", "author_names": [ "Vincent Martin", "Gwenael Dunand", "Victor Moncada", "M Jouve", "J M Travere" ], "corpus_id": 7237567, "doc_id": "7237567", "n_citations": 29, "n_key_citations": 0, "score": 0, "title": "New field programmable gate array based image oriented acquisition and real time processing applied to plasma facing component thermal monitoring.", "venue": "The Review of scientific instruments", "year": 2010 }, { "abstract": "Small solid state photomultipliers (SSPMs) are an alternative scintillator light detection technology to traditional photomultiplier tubes that offer advantages such as lower bias voltages and insensitivity to magnetic fields. A digital spectrometer using a commercially available SSPM was constructed and characterized at Oregon State University as a prototype for small, highly mobile, low power, robust spectroscopy devices. The SSPM has over 19,000 microcells in a photo sensitive area of 6.32 x 6.32 mm and was coupled to 6 x 6 x 10 mm reflectively coated CsI(Tl) crystals. The rest of the spectrometer consists of a fast preamplifier and 200 MHz, 12 bit digital pulse processor based around a field programmable gate array (FPGA) The efficiency, resolution, linearity, and peak to Compton ratio of the system were characterized.", "author_names": [ "Eric M Becker", "Abi T Farsoni", "Abdulsalam M Alhawsawi", "Bemnet Alemayehu" ], "corpus_id": 28624328, "doc_id": "28624328", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Small Prototype Gamma Spectrometer Using CsI(Tl) Scintillator Coupled to a Solid State Photomultiplier", "venue": "IEEE Transactions on Nuclear Science", "year": 2013 }, { "abstract": "The small animal positron emission tomography (PET) is dedicated to small animal imaging, which requires high position and energy precision, as well as good flexibility and efficiency of the electronics. This paper presents the design of a digital signal processing logic for a marmoset brain PET system based on lutetium yttrium oxyorthosilicate (LYSO) crystal arrays, SiPMs, and the resistive network readout method. We implement 32 channel signal processing in a single Xilinx Artix 7 Field Programmable Gate Array (FPGA) The logic is designed to support four online modes which are regular data processing mode, flood map construction mode, energy spectrum construction mode, and raw data mode. Several functions are integrated, including 2 D) raw position calculation, crystal locating, events filtering, and synchronization detection. Furthermore, a series of online corrections is also integrated, such as photon peak correction to 511 keV and time measurement result correction with crystal granularity. A gigabit ethernet interface is utilized for data transfer, look up tables (LUTs) configuration, and command issuing. The pipeline logic works at 125 MHz with a signal processing capability beyond the required data rate of 1 000 000 events/s/channel. A series of initial tests is conducted. The results indicate that the logic design meets the application requirement.", "author_names": [ "Jiaming Lu", "Lei Zhao", "Kairen Chen", "Peipei Deng", "Bowen Li", "Shubin Liu", "Qi An" ], "corpus_id": 133008972, "doc_id": "133008972", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Real Time FPGA Based Digital Signal Processing and Correction for a Small Animal PET", "venue": "IEEE Transactions on Nuclear Science", "year": 2019 }, { "abstract": "The demand for digital down converter (DDC) is the cornerstone technology in software radio standard, which converts the frequency translation, especially in down converted complex output. This paper briefs design and implementation of reconfigurable DDC that can process input bandwidth about 70MHz to 270 KHz to meet the specifications of Global System for Mobile (GSM) receiver. The proposed design consists of COordinate Rotation Digital Computer (CORDIC) processor and multi rate decimation filters. By using CORDIC processor the design has achieved maximum spurious free dynamic range (SFDR) Moreover, implementation of multi rate decimation filter requires small hardware resources and improves the performance of the DDC design. The proposed DDC has been designed and tested on Xilinx Kintex 7 field programmable gate array (FPGA) board. The advantages of using this flexible DDC can produce a specific output. Experimental results show that the proposed DDC is operated on high processing speed with optimum area to provide cost effective solution in mobile application.", "author_names": [ "Debarshi Datta", "Partha Mitra", "Himadri Sekhar Dutta" ], "corpus_id": 221386271, "doc_id": "221386271", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "FPGA Based Digital Down Converter for GSM Application", "venue": "2020 IEEE VLSI DEVICE CIRCUIT AND SYSTEM (VLSI DCS)", "year": 2020 }, { "abstract": "Field Programmable Gate Array's (FPGAs) are especially popular for prototyping integrated circuits designs. This paper describes the simulation of Peak detector and counter circuit based on FPGAs technology. Complete circuit was designed by writing appropriate program in Very High Speed Integrated Circuit Hardware Description Language (VHDL) ISE foundation 6.1. The designed system was simulated using Modelsim simulator SE f.A maximum frequency of 190.513MHZ was reached with a minimum period of 5.249ns. 12 out of 3584 slices were used. Our system can be implemented on Xilinx Spartan 3 XC3S400~4pq208.", "author_names": [ "Amit Pal Singh" ], "corpus_id": 64407028, "doc_id": "64407028", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Design and Simulation of FPGA based Digital System for Peak Detection and Counting", "venue": "", "year": 2013 }, { "abstract": "Embedded computer vision based smart systems raise challenging issues in many research fields, including real time vision processing, communication protocols or distributed algorithms. The amount of data generated by cameras using high resolution image sensors requires powerful computing systems to be processed at digital video frame rates. Consequently, the design of efficient and flexible smart cameras, with on board processing capabilities, has become a key issue for the expansion of smart vision systems relying on decentralised processing at the image sensor node level. In this context, field programmable gate arrays (FPGA) based platforms, supporting massive data parallelism, offer large opportunities to match real time processing constraints compared with platforms based on general purpose processors. In this study, the authors describe the implementation, on such a platform, of a configurable object detection application, reformulated according to the dataflow model of computation. The application relies on the computation of the histogram of oriented gradients and a linear SVM based classification. It is described using the CAPH programming language, allowing efficient hardware descriptions to be generated automatically from high level dataflow specifications without prior knowledge of hardware description languages such as VHDL or Verilog. Results show that the performance of the generated code does not suffer from a significant overhead compared with handwritten HDL code.", "author_names": [ "Cedric Bourrasset", "Luca Maggiani", "Jocelyn Serot", "Francois Berry" ], "corpus_id": 38549457, "doc_id": "38549457", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Dataflow object detection system for FPGA based smart camera", "venue": "IET Circuits Devices Syst.", "year": 2016 }, { "abstract": "This paper presents the software and hardware design aspects of the first digital MIT system. Excitation signal generation, receiving signal demodulation and channel multiplexing control are all implemented inside a Xilinx FPGA (Spartan III) The image reconstruction software is written in VC+ and real time images up to 200 frames /second can be achieved for 50K Hz excitation. Fitted with an 8 coil MIT sensor, the digital system delivers a much higher signal to noise ratio (SNR) and image stability compared to the analog system previously designed. Metallic samples of different shapes and arrangements were imaged, which confirms the performance of the system.", "author_names": [ "Wuliang Yin", "Guang Chen", "Jian Jiang", "Ziqiang Cui" ], "corpus_id": 30329741, "doc_id": "30329741", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "The design of a FPGA based digital magnetic induction tomography (MIT) system for metallic object imaging", "venue": "2010 IEEE Instrumentation Measurement Technology Conference Proceedings", "year": 2010 } ]
Green chemical mechanical polishing of sapphire wafers using a novel slurry
[ { "abstract": "Toxic and corrosive solutions are widely used in the preparation of abrasives and chemical mechanical polishing (CMP) of sapphire wafers, resulting in potential environmental pollution. Developing a novel green CMP technique to achieve light emitting diode sapphire wafers is a significant challenge. In this study, a novel green CMP slurry, consisting of silica, sorbitol, aminomethyl propanol, and deionized water was developed for sapphire wafers. After CMP, the sapphire wafers were cleaned with deionized water and dried with compressed air, which is a green process. After CMP, the surface roughness Ra of the sapphire wafer surface with an area of 5 x 5 mm2 was 0.098 nm, which is the lowest surface roughness reported to date for sapphire wafers. Tetrahydroxy coordinated Al(OH)4 ions were produced in the alkaline CMP slurry, and chelation occurred between sorbitol and these ions. The proposed green CMP has potential applications in the semiconductor and microelectronics industries.", "author_names": [ "Wenxiang Xie", "Zhenyu J Zhang", "Longxing Liao", "Jia-wen Liu", "Hongjiu Su", "Shudong Wang", "Dongming Guo" ], "corpus_id": 222154578, "doc_id": "222154578", "n_citations": 19, "n_key_citations": 1, "score": 1, "title": "Green chemical mechanical polishing of sapphire wafers using a novel slurry.", "venue": "Nanoscale", "year": 2020 }, { "abstract": "Abstract At present, corrosive ingredients are widely employed in chemical mechanical polishing (CMP) of sapphire, bringing a potential threat to both people and environment. This results in high cost and long processing time on the treatment of CMP slurry of sapphire. It is a challenge to develop a novel green CMP for sapphire to meet the stringent requirements of high performance products. In this study, a novel green CMP is proposed for sapphire, consisting of silica nanoparticles of 50 nm, triethanolamine (TEA) sodium metasilicate nonahydrate, and deionized water. After green CMP, surface roughness Ra, root mean square (rms) and peak to valley (PV) are 0.11, 0.139, and 1.65 nm, respectively. Material removal rate is 3.31 mm/h during green CMP. To the best of our knowledge, surface roughness Ra and rms after green CMP developed are the lowest on a sapphire wafer, compared with those reported previously. The CMP mechanism is elucidated by X ray photoelectron spectroscopy (XPS) and infrared (IR) spectra. Sapphire formed Al(OH)4 ions in an alkaline environment, which was chelated by TEA, and removed from the surface of sapphire. These findings provide new insights to fabricate high performance devices of sapphire for the use in semiconductor and microelectronic industries.", "author_names": [ "Zhenyu J Zhang", "Weibing Hu", "Lezhen Zhang", "Longxing Liao" ], "corpus_id": 234041716, "doc_id": "234041716", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Chemical mechanical polishing for sapphire wafers using a developed slurry", "venue": "", "year": 2021 }, { "abstract": "Silicon carbide (SiC) single crystals, along with sapphire and silicon, are one of most important substrates for high brightness LED fabrications. Owing to extremely high hardness (Mohs' scale of 9.5) and chemical inertness, the polishing rate of SiC with conventional chemical mechanical polishing (CMP) methods is not high, and surface scratches are also inevitable because of using slurry containing hard abrasives such as silica particles. Here artemisinin (Qinghaosu) crystals, very soft molecular solids, were found, for the first time to the best of our knowledge, to effectively polish SiC wafers even in pure water as demonstrated by proof of concept scratching experiments using atomic force microscopy (AFM) The underlying mechanism is attributed to activated oxidation of SiC by mechanically released reactive *OH free radicals from the endoperoxide bridges. The preliminary results reported here have important implications for developing novel alternative green and scratch free polishing methods for hard brittle substrates including SiC and others.", "author_names": [ "Yu-rong Zhu", "Dan Zhang", "Yang Gan", "Feihu Zhang" ], "corpus_id": 14776167, "doc_id": "14776167", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Marrying Medicine and Materials: Artemisinin (Qinghaosu) Particle is Soft Enough for Scratching Hard SiC Wafer in Water", "venue": "", "year": 2016 }, { "abstract": "Non spherical colloidal silica nanoparticle was prepared by a simple new method, and its particle size distribution and shape morphology were characterized by dynamic light scattering (DLS) and the Focus Ion Beam (FIB) system. This kind of novel colloidal silica particles can be well used in chemical mechanical polishing (CMP) of sapphire wafer surface. And the polishing test proves that non spherical colloidal silica slurry shows much higher material removal rate (MRR) with higher coefficient of friction (COF) when compared to traditional large spherical colloidal silica slurry with particle size 80 nm by DLS. Besides, sapphire wafer polished by non spherical abrasive also has a good surface roughness of 0.460 6 nm. Therefore, non spherical colloidal silica has shown great potential in the CMP field because of its higher MRR and better surface roughness.", "author_names": [ "Huijun Kong", "Dan Wang", "Weili Liu", "Zhitang Song" ], "corpus_id": 139749177, "doc_id": "139749177", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Preparation of Non spherical Colloidal Silica Nanoparticle and Its Application on Chemical Mechanical Polishing of Sapphire", "venue": "Journal of Wuhan University of Technology Mater. Sci. Ed.", "year": 2019 }, { "abstract": "Abstract In this paper, a novel non noble metal catalyst (Fe N x /C) is used to improve the removal mass of sapphire as well as obtain atomically smooth sapphire wafer surfaces. The results indicate that Fe N x /C shows good catalytic activity towards sapphire removal rate. And the material removal rates (MRRs) are found to vary with the catalyst content in the polishing fluid. Especially that when the polishing slurry mixes with 16 ppm Fe N x /C shows the maximum MRR and its removal mass of sapphire is 38.43 nm/min, more than 15.44% larger than traditional CMP using the colloidal silicon dioxide (SiO 2 without Fe N x /C. Catalyst assisted chemical mechanical polishing of sapphire is studied with X ray photoelectron spectroscopy (XPS) It is found that the formation of a soft hydration layer (boehmite, g AlOOH or g AlO(OH) on sapphire surface facilitates the material removal and achieving fine surface finish on basal plane. Abrasives (colloid silica together with magnetite, ingredient of Fe N x /C) with a hardness between boehmite and sapphire polish the c plane of sapphire with good surface finish and efficient removal. Fe 2 O 3 Fe 3 O 4 pyridinic N as well as pyrrolic N group would be the catalytical active sites and accelerate this process. Surface quality is characterized with atomic force microscopy (AFM) The optimum CMP removal by Fe N x /C also yields a superior surface finish of 0.078 nm the average roughness (Ra)", "author_names": [ "Li Xu", "Chunli Zou", "Xiaolei Shi", "Guoshun Pan", "Luo Guihai", "Yan Zhou" ], "corpus_id": 136739515, "doc_id": "136739515", "n_citations": 37, "n_key_citations": 0, "score": 0, "title": "Fe Nx/C assisted chemical mechanical polishing for improving the removal rate of sapphire", "venue": "", "year": 2015 }, { "abstract": "Recently, sapphire has been used in a wide range of applications including optics, consumer electronics, and especially the rapidly growing LED wafer manufacturing. This paper investigates effects of a novel compound slurry composed of micron scaled diamond abrasives and various nano platelets of graphene oxide (GO) for improving lapping performance of c plane single crystal aluminum oxide (Al2O3) sapphire wafers. Four kinds of graphenes including GO, reduced graphene oxide (RGO) ML RGO (laminate) and MF RGO (few layer) are added into the diamond slurry to achieve compound slurries. Those compound slurries have been prepared with various graphene weight fractions in the range of 0.3 to 2.0 wt% by LP (low power) or HP (high power) ultrasonication with different time spans in the range of 10 min to 48 h to adjust size of GOs. For the lapping process conducted by 10 min HP ultrasonicated GO (2.0 wt%/diamond slurry, combination of medium down force pressure and the highest platen rotation speed of 45 kPa/80 rpm results in highest material removal rate (MRR) of 926.73 nm/min, which is 324% higher than MRR by pure diamond slurry. It is caused by high reactivity of GOs with sapphire wafer. As lapped at pressure/speed of 45 kPa/70 rpm by ultrasonicated GO (0.5 wt%/diamond compound slurry, the average surface roughness Ra of wafer can reach 7.19 nm, which is 0.7% lower than 7.24 nm by pure diamond slurry. Experimental results demonstrate that the optimized planarization of sapphire wafer with high MRR and low surface roughness can be achieved using the GO compound slurry when the mechanical removal effect and the chemical reaction mechanism are in synergistic equilibrium. The XPS and EDS analyses clearly support the material removal model that a reactant aluminum carbonate layer and a residual carbon layer exist and both are efficiently removed by diamond abrasives. Results of this study can be applied to further explore high volume production of CMP of sapphire wafers.", "author_names": [ "Hsien-Kuang Liu", "Chao-Chang A Chen", "Wei-Chung Chen" ], "corpus_id": 214214789, "doc_id": "214214789", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Effects of compound diamond slurry with graphene for lapping of sapphire wafers", "venue": "", "year": 2020 }, { "abstract": "Abstract Chemical mechanical polishing of sapphire with a novel catalyst (SoFeIII) based colloidal silicon dioxide has been studied with high resolution transmission electron microscopy and X ray diffraction. It has been found that a polytype of aluminun trihydroxide is formed on the polished crystal surface when SoFeIII 80 degC catalyst is used, while aluminum silicate hydrate layer is found on the polished sapphire surface when burnished with catalyst free slurry. And the novel catalyst plays effective performance towards improving the removal rate of sapphire, and its removal rate is 7.21 mm/h, 1.66 times than the material removal rate obtained with catalyst free slurry. Additionally, the optimum CMP removal by SoFeIII 80 degC yielded an ultra smooth wafer surface with an average roughness of 0.0543 nm.", "author_names": [ "Li Xu", "Xin Zhang", "Chengxi Kang", "Rongrong Wang", "Chunli Zou", "Yan Zhou", "Guoshun Pan" ], "corpus_id": 139606952, "doc_id": "139606952", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Preparation of a novel catalyst (SoFe III and its catalytic performance towards the removal rate of sapphire substrate during CMP process", "venue": "", "year": 2018 }, { "abstract": "Abstract A novel semi empirical model was developed for predicting the material removal rate (MRR) during chemical mechanical polishing (CMP) based on the following assumptions: plastic contact at the wafer particle interface, elastic contact at the pad particle interface, a particle size distribution, and a randomly distributed surface roughness of the polishing pad. The proposed model incorporates the effects of particle size, concentration, and distribution, as well as the slurry flow rate, pad surface topography, material properties, and chemical reactions during the silicon dioxide (SiO 2 CMP. To obtain the unknown parameters and ensure the validity of the model, a SiO 2 CMP experiment was conducted by using various sized CMP slurries. The spatial distribution of the MRRs is expressed with respect to the normal contact stress distribution and the relative velocity distribution. The proposed MRR model can be used for the development of a CMP simulator, the optimization of CMP process parameters, and the design of next generation CMP machines.", "author_names": [ "H S Lee", "Hae-do Jeong", "David A Dornfeld" ], "corpus_id": 137581224, "doc_id": "137581224", "n_citations": 46, "n_key_citations": 0, "score": 0, "title": "Semi empirical material removal rate distribution model for SiO2 chemical mechanical polishing (CMP) processes", "venue": "", "year": 2013 }, { "abstract": "To meet the stringent requirements of device integration and manufacture, surface defects and mechanical stresses that arise during chemical mechanic planarization (CMP) must be reduced. Towards this end, we have synthesized multiple hybrid and composite particles on micron length scales consisting of siloxane co polymers functionalized with inorganic nanoparticles. These particles can be easily tailored during synthesis, leading to softer or harder abrasion when desired. Upon using these particles for the planarization of silicon oxide wafers, we obtain smooth surfaces with reduced scratches and minimal particle deposition, which is an improvement from conventional abrasive materials like pure silica, ceria and alumina nanoparticle slurries. Tribological characteristics during polishing were examined using a bench top CMP tester to evaluate the in situ co efficient of friction. Characterization of the hybrid and composite particles has been done using infrared spectroscopy, dynamic light scattering, and electron microscopy. Surface roughness of the wafers was examined using atomic force and optical microscopy while removal rate measurements were conducted using ellipsometry at multiple angles.", "author_names": [ "Cecil A Coutinhoa", "Subrahmanya R Mudhivarthib", "A Kumarb", "Vinay K Guptaa" ], "corpus_id": 9486924, "doc_id": "9486924", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Chemical Mechanical Polishing of Oxide Layers using Novel Ceria Polymer Microcomposites", "venue": "", "year": 2008 }, { "abstract": "In this study, the chemical mechanical polishing (CMP) of iridium and iridium oxide has been investigated. The results show that it is possible to polish this highly inert noble metal and its oxide with removal rates and selectivities that are satisfactory for damascene processes in semiconductor manufacturing. All slurries are based on commercially available abrasives and chemicals. Using blanket wafers, two particular slurry systems have been systematically studied. Concentration variations of abrasive as well as oxidizer and base have been investigated for iridium and iridium oxide, respectively. The dependence of the removal rate on polishing parameters such as time, pressure, and rotational speeds have been investigated. Iridium and iridium oxide removal rates up to 50 and 260 nm/min with selectivities to SiO 2 up to 30:1 and 50:1 could be reached, respectively. Based on the results obtained on planar wafers slurries with optimized parameters were applied to structured wafers. The dishing effect is very small <10 nm) both in small <1 mm) and larger (10 mm width) structures. Erosion of tetraethyl orthosilicate is in the range between 20 and 40 nm, and the surface roughness (root mean square 0.5 2 nm) measured by atomic force microscopy as well as the depth of scratches (5 15 nm) were comparable to those of copper CMP. Overall, the process performance demonstrated on planar and patterned wafers fully satisfies production requirements. Therefore, these novel polishing processes allow, for the first time, the implementation of noble metal damascene processes in semiconductor manufacturing.", "author_names": [ "Gerd Mainka", "Gerhard A Beitel", "Rainer Florian Schnabel", "Annette Saenger", "Christine Dehm" ], "corpus_id": 96153931, "doc_id": "96153931", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Chemical Mechanical Polishing of Iridium and Iridium Oxide for Damascene Processes", "venue": "", "year": 2001 } ]
Fundamentals of Materials Science and Engineering: An Integrated Approach, 4th Edition
[ { "abstract": "Chapter 1 Introduction. 1.1 Historical Perspective 1.2 Materials Science and Engineering 1.3 Why Study Materials Science and Engineering? 1.4 Classification of Materials Materials of Importance Carbonated Beverage Containers 1.5 Advanced Materials 1.6 Modern Materials Needs 1.7 Processing/Structure/Properties/Performance Correlations Chapter 2 Atomic Structure and Interatomic Bonding. 2.1 Introduction 2.2 Fundamental Concepts 2.3 Electrons in Atoms 2.4 The Periodic Table 2.5 Bonding Forces and Energies 2.6 Primary Interatomic Bonds 2.7 Secondary Bonding or van der Waals Bonding Materials of Importance Water (Its Volume Expansion Upon Freezing) 2.8 Molecules Chapter 3 Structures of Metals and Ceramics 3.1 Introduction 3.2 Fundamental Concepts 3.3 Unit Cells 3.4 Metallic Crystal Structures 3.5 Density Computations Metals 3.6 Ceramic Crystal Structures 3.7 Density Computations Ceramics 3.8 Silicate Ceramics 3.9 Carbon Materials of Importance Carbon Nanotubes 3.10 Polymorphism and Allotropy Material of Importance Tin (Its Allotropic Transformation) 3.11 Crystal Systems 3.12 Point Coordinates 3.13 Crystallographic Directions 3.14 Crystallographic Planes 3.15 Linear and Planar Densities 3.16 Close Packed Crystal Structures 3.17 Single Crystals 3.18 Polycrystalline Materials 3.19 Anisotropy 3.20 X Ray Diffraction: Determination of Crystal Structures 3.21 Noncrystalline Solids Chapter 4 Polymer Structures 4.1 Introduction 4.2 Hydrocarbon Molecules 4.3 Polymer Molecules 4.4 The Chemistry of Polymer Molecules 4.5 Molecular Weight 4.6 Molecular Shape 4.7 Molecular Structure 4.8 Molecular Configurations 4.9 Thermoplastic and Thermosetting Polymers 4.10 Copolymers 4.11 Polymer Crystallinity 4.12 Polymer Crystals Chapter 5 Imperfections in Solids 5.1 Introduction 5.2 Point Defects in Metals 5.3 Point Defects in Ceramics 5.4 Impurities in Solids 5.5 Point Defects in Polymers 5.6 Specification of Composition 5.7 Dislocations Linear Defects 5.8 Interfacial Defects Materials of Importance Catalysts (and Surface Defects) 5.9 Bulk or Volume Defects 5.10 Atomic Vibrations 5.11 Basic Concepts of Microscopy 5.12 Microscopic Techniques 5.13 Grain Size Determination Chapter 6 Diffusion 6.1 Introduction 6.2 Diffusion Mechanisms 6.3 Steady State Diffusion 6.4 Nonsteady State Diffusion 6.5 Factors That Influence Diffusion 6.6 Diffusion in Semiconducting Materials Material of Importance Aluminum for Integrated Circuit Interconnects 6.7 Other Diffusion Paths 6.8 Diffusion in Ionic and Polymeric Materials Chapter 7 Mechanical Properties 7.1 Introduction 7.2 Concepts of Stress and Strain 7.3 Stress Strain Behavior 7.4 Anelasticity 7.5 Elastic Properties of Materials 7.6 Tensile Properties 7.7 True Stress and Strain 7.8 Elastic Recovery after Plastic Deformation 7.9 Compressive, Shear, and Torsional Deformation 7.10 Flexural Strength 7.11 Elastic Behavior 7.12 Influence of Porosity on the Mechanical Properties of Ceramics 7.13 Stress Strain Behavior 7.14 Macroscopic Deformation 7.15 Viscoelastic Deformation 7.16 Hardness 7.17 Hardness of Ceramic Materials 7.18 Tear Strength and Hardness of Polymers 7.19 Variability of Material Properties 7.20 Design/Safety Factors Chapter 8 Deformation and Strengthening Mechanisms 8.1 Introduction 8.2 Historical 8.3 Basic Concepts of Dislocations 8.4 Characteristics of Dislocations 8.5 Slip Systems 8.6 Slip in Single Crystals 8.7 Plastic Deformation of Polycrystalline Metals 8.8 Deformation by Twinning 8.9 Strengthening by Grain Size Reduction 8.10 Solid Solution Strengthening 8.11 Strain Hardening 8.12 Recovery 8.13 Recrystallization 8.14 Grain Growth 8.15 Crystalline Ceramics 8.16 Noncrystalline Ceramics 8.17 Deformation of Semicrystalline Polymers 8.18 Factors That Influence the Mechanical Properties of Semicrystalline Polymers Materials of Importance Shrink Wrap Polymer Films 8.19 Deformation of Elastomers Chapter 9 Failure 9.1 Introduction 9.2 Fundamentals of Fracture 9.3 Ductile Fracture 9.4 Brittle Fracture 9.5 Principles of Fracture Mechanics 9.6 Brittle Fracture of Ceramics 9.7 Fracture of Polymers 9.8 Fracture Toughness Testing 9.9 Cyclic Stresses 9.10 The S N Curve 9.11 Fatigue in Polymeric Materials 9.12 Crack Initiation and Propagation 9.13 Factors That Affect Fatigue Life 9.14 Environmental Effects 9.15 Generalized Creep Behavior 9.16 Stress and Temperature Effects 9.17 Data Extrapolation Methods 9.18 Alloys for High Temperature Use 9.19 Creep in Ceramic and Polymeric Materials Chapter 10 Phase Diagrams 10.1 Introduction 10.2 Solubility Limit 10.3 Phases 10.4 Microstructure 10.5 Phase Equilibria 10.6 One Component (or Unary) Phase Diagrams 10.7 Binary Isomorphous Systems 10.8 Interpretation of Phase Diagrams 10.9 Development of Microstructure in Isomorphous Alloys 10.10 Mechanical Properties of Isomorphous Alloys 10.11 Binary Eutectic Systems Materials of Importance Lead Free Solders 10.12 Development of Microstructure in Eutectic Alloys 10.13 Equilibrium Diagrams Having Intermediate Phases or Compounds 10.14 Eutectoid and Peritectic Reactions 10.15 Congruent Phase Transformations 10.16 Ceramic Phase Diagrams 10.17 Ternary Phase Diagrams 10.18 The Gibbs Phase Rule 10.19 The Iron Iron Carbide (Fe Fe3C) Phase Diagram 10.20 Development of Microstructure in Iron Carbon Alloys 10.21 The Influence of Other Alloying Elements Chapter 11 Phase Transformations 11.1 Introduction 11.2 Basic Concepts 11.3 The Kinetics of Phase Transformations 11.4 Metastable versus Equilibrium States 11.5 Isothermal Transformation Diagrams 11.6 Continuous Cooling Transformation Diagrams 11.7 Mechanical Behavior of Iron Carbon Alloys 11.8 Tempered Martensite 11.9 Review of Phase Transformations and Mechanical Properties for Iron Carbon Alloys Materials of Importance Shape Memory Alloys 11.10 Heat Treatments 11.11 Mechanism of Hardening 11.12 Miscellaneous Considerations 11.13 Crystallization 11.14 Melting 11.15 The Glass Transition 11.16 Melting and Glass Transition Temperatures 11.17 Factors That Influence Melting and Glass Transition Temperatures Chapter 12 Electrical Properties 12.1 Introduction 12.2 Ohm's Law 12.3 Electrical Conductivity 12.4 Electronic and Ionic Conduction 12.5 Energy Band Structures in Solids 12.6 Conduction in Terms of Band and Atomic Bonding Models 12.7 Electron Mobility 12.8 Electrical Resistivity of Metals 12.9 Electrical Characteristics of Commercial Alloys Materials of Importance Aluminum Electrical Wires 12.10 Intrinsic Semiconduction 12.11 Extrinsic Semiconduction 12.12 The Temperature Dependence of Carrier Concentration 12.13 Factors that Affect Carrier Mobility 12.14 The Hall Effect 12.15 Semiconductor Devices 12.16 Conduction in Ionic Materials 12.17 Electrical Properties of Polymer 12.18 Capacitance 12.19 Field Vectors and Polarization 12.20 Types of Polarization 12.21 Frequency Dependence of the Dielectric Constant 12.22 Dielectric Strength 12.23 Dielectric Materials 12.24 Ferroelectricity 12.25 Piezoelectricity Chapter 13 Types and Applications of Materials 13.1 Introduction 13.2 Ferrous Alloys 13.3 Nonferrous Alloys Materials of Importance Metal Alloys Used for Euro Coins 13.4 Glasses 13.5 Glass Ceramics.", "author_names": [ "William D Callister" ], "corpus_id": 108022793, "doc_id": "108022793", "n_citations": 388, "n_key_citations": 3, "score": 0, "title": "Fundamentals of Materials Science and Engineering: An Integrated Approach, 2nd Edition", "venue": "", "year": 2004 }, { "abstract": "Thank you very much for downloading fundamentals of materials science and engineering an integrated approach. Maybe you have knowledge that, people have search hundreds times for their chosen readings like this fundamentals of materials science and engineering an integrated approach, but end up in infectious downloads. Rather than enjoying a good book with a cup of coffee in the afternoon, instead they cope with some malicious bugs inside their desktop computer.", "author_names": [ "Christina Kluge" ], "corpus_id": 184384566, "doc_id": "184384566", "n_citations": 276, "n_key_citations": 29, "score": 1, "title": "Fundamentals Of Materials Science And Engineering An Integrated Approach", "venue": "", "year": 2016 }, { "abstract": "What do you do to start reading introduction to computing and programming in python a multimedia approach 2nd edition? Searching the book that you love to read first or find an interesting book that will make you want to read? Everybody has difference with their reason of reading a book. Actuary, reading habit must be from earlier. Many people may be love to read, but not a book. It's not fault. Someone will be bored to open the thick book with small words to read. In more, this is the real condition. So do happen probably with this introduction to computing and programming in python a multimedia approach 2nd edition.", "author_names": [ "Mark Guzdial", "Barbara Ericson" ], "corpus_id": 6250099, "doc_id": "6250099", "n_citations": 55, "n_key_citations": 5, "score": 0, "title": "Introduction to Computing and Programming in Python a Multimedia Approach, 4th Edition", "venue": "", "year": 2016 }, { "abstract": "We describe the .screened Korringa Kohn Rostoker (KKR) method and the thirdgeneration linear muffin tin orbital (LMTO) method for solving the single particle Schrodinger equation for a MT potential. In the screened KKR method, the eigenvectors cRLti are given as the non zero solutions, and the energies PS,as those for which such solutions can be found, of the linear homogeneous equations: J^RL KR,L, RL (e; cRLii 0, where K\" (e) is the screened KKR matrix. The screening is specified by the boundary condition that, when a screened spherical wave 4)RL(e,rR) is expanded in spherical harmonics VR'L' (fss' about its neighboring sites R' then each component either vanishes at a radius, rR'=aRiLi, or is a regular solution at that site. When the corresponding \"hard\" spheres are chosen to be nearly touching, then the KKR matrix is usually short ranged and its energy dependence smooth over a range of order 1 Ry around the centre of the valence band. The KKR matrix, K (e, at a fixed, arbitrary energy turns out to be the negative of the Hamiltonian, and its first energy derivative, K (e, to be the overlap matrix in a basis of kinked partial waves, $M (e, rR) each of which is a partial wave inside the MT sphere, tailed with a screened spherical wave in the interstitial, or taking the other point of view, a screened spherical wave in the interstitial, augmented by a partial wave inside the sphere. When of short range, K (e) has the two centre tight binding (TB) form and can be generated in real space, simply by inversion of a positive definite matrix for a cluster. The LMTOs, XRL [ev) are smooth orbitals constructed from $RL{ev,rR) and $RL{ev,rR) and the Hamiltonian and overlap matrices in the basis of LMTOs are expressed solely in terms of K (e, and its first three energy derivatives. The errors of the single particle energies PS; obtained from the Hamiltonian and overlap matrices in the (e,)and x {ev) bases are respectively of second and fourth order in e, e, Third generation LMTO sets give wave functions which are correct to order e; ev, not only inside the MT spheres, but also in the interstitial region. As a consequence, the simple and popular formalism which previously resulted from the atomic spheres approximation (ASA) now holds in general, that is, it includes downfolding and the combined correction. Downfolding to few orbital, possibly short ranged, low energy, and possibly orthonormal Hamiltonians now works exceedingly well, as is demonstrated for a high temperature superconductor. First principles sp and spd TB Hamiltonians for the valence and lowest conduction bands of silicon are derived. Finally, we prove that the new method treats overlap of the potential wells correctly to leading order and we demonstrate how this can be exploited to get rid of the empty spheres in the diamond structure.", "author_names": [ "Mark van Schilfgaarde", "Walter R L Lambrecht" ], "corpus_id": 136499559, "doc_id": "136499559", "n_citations": 139, "n_key_citations": 5, "score": 0, "title": "Tight binding approach to Computational Materials Science", "venue": "", "year": 1998 }, { "abstract": "Floods are natural and seasonal phenomena, which play an important environmental role, but when they take place at the built environments, many losses of different kinds occur. By its side, urban growth is one of the main causes of urban floods aggravation. Changes in land use occupation, with vegetation removal and increasing of impervious rates lead to greater run off volumes flowing faster. Intense urbanisation is a relatively recent process; however, floods and drainage concerns are related to city development since ancient times. Drainage systems are part of a city infrastructure and they are an important key in urban life. If the drainage system fails, cities become subjected to floods, to possible environmental degradation, to sanitation and health problems and to city services disruption. On the other hand, urban rivers, in different moments of cities development history, have been considered as important sources of water supply, as possible defences for urban areas, as a way of transporting goods, and as a means of waste conveying.", "author_names": [ "Marcelo Gomes Miguez", "Aline Pires Verol", "Paulo Roberto Ferreira Carneiro" ], "corpus_id": 6639232, "doc_id": "6639232", "n_citations": 27, "n_key_citations": 0, "score": 0, "title": "Sustainable Drainage Systems: An Integrated Approach, Combining Hydraulic Engineering Design, Urban Land Control and River Revitalisation Aspects", "venue": "", "year": 2012 }, { "abstract": "The fourth edition of this comprehensive course supports individual enquiry and research as well as encouraging discussion and debate. It sets concepts and skills in context and can be used by students following any A Level specification or the International Baccalaureate.", "author_names": [ "David Waugh" ], "corpus_id": 140612106, "doc_id": "140612106", "n_citations": 163, "n_key_citations": 12, "score": 0, "title": "Geography: An Integrated Approach", "venue": "", "year": 1990 }, { "abstract": "(NOTE: Each chapter concludes with a Summary, New Terms and Symbols, References, and a Problems and Questions section. 1. Introduction. 2. Structure and Deformation in Materials. 3. A Survey of Engineering Materials. 4. Mechanical Testing: Tension Test and Other Basic Tests. 5. Stress Strain Relationships and Behavior. 6. Review of Complex and Principal States of Stress and Strain. 7. Yielding and Fracture under Combined Stresses. 8. Fracture of Cracked Members. 9. Fatigue of Materials: Introduction and Stress Based Approach. 10. Stress Based Approach to Fatigue: Notched Members. 11. Fatigue Crack Growth. 12. Plastic Deformation Behavior and Models for Materials. 13. Stress Strain Analysis of Plastically Deforming Members. 14. Strain Based Approach to Fatigue. 15. Time Dependent Behavior: Creep and Damping. Appendix A: Review of Selected Topics from Mechanics of Materials. Appendix B: Statistical Variation in Materials Properties. Bibliography. Index.", "author_names": [ "N E Dowling" ], "corpus_id": 135563866, "doc_id": "135563866", "n_citations": 1046, "n_key_citations": 68, "score": 0, "title": "Mechanical Behavior of Materials: Engineering Methods for Deformation, Fracture, and Fatigue", "venue": "", "year": 1993 }, { "abstract": "Energy and energy transfer properties of common substances first law of thermodynamics entropy and the second law of thermodynamics thermodynamic cycle analysis and applications to gas cycles vapor cycle analysis analysis using the second law of thermodynamics general property relations and equations of state multicomponent systems without chemical reaction chemical reactions and combustion phase and chemical equilibrium introduction to microscopic thermodyanmics.", "author_names": [ "John R Howell", "Richard O Buckius" ], "corpus_id": 93950649, "doc_id": "93950649", "n_citations": 45, "n_key_citations": 1, "score": 0, "title": "Fundamentals of Engineering Thermodynamics", "venue": "", "year": 1986 }, { "abstract": "1 Getting Started: Introductory Concepts and Definitions. 1.1 Using Thermodynamics. 1.2 Defining Systems. 1.3 Describing Systems and Their Behavior. 1.4 Measuring Mass, Length, Time, and Force. 1.5 Specific Volume. 1.6 Pressure. 1.7 Temperature. Chapter Summary and Study Guide. 2 Energy and the First Law of Thermodynamics. 2.1 Reviewing Mechanical Concepts of Energy. 2.2 Broadening Our Understanding of Work. 2.3 Broadening Our Understanding of Energy. 2.4 Energy Transfer by Heat. 2.5 Energy Accounting: Energy Balance for Closed Systems. 2.6 Energy Analysis of Cycles. Chapter Summary and Study Guide. 3 Evaluating Properties. 3.1 Getting Started. Evaluating Properties: General Considerations. 3.2 p v T Relation. 3.3 Studying Phase Change. 3.4 Retrieving Thermodynamic Properties. 3.5 Evaluating Pressure, Specific Volume, and Temperature. 3.6 Evaluating Specific Internal Energy and Enthalpy. 3.7 Evaluating Properties Using Computer Software. 3.8 Applying the Energy Balance Using Property Tables and Software. Chapter Summary and Study Guide. 4 Control Volume Analysis Using Energy. 4.1 Conservation of Mass for a Control Volume. 4.2 Forms of the Mass Rate Balance. 4.3 Applications of the Mass Rate Balance. 4.4 Conservation of Energy for a Control Volume. Chapter Summary and Study Guide. 5 The Second Law of Thermodynamics. 5.1 Introducing the Second Law. 5.2 Statements of the Second Law. 5.3 Identifying Irreversibilities. 5.4 Interpreting the Kelvin Planck Statement. 5.5 Applying the Second Law to Thermodynamic Cycles. 5.6 Second Law Aspects of Power Cycles Interacting with Two Reservoirs. Chapter Summary and Study Guide. 6 Using Entropy. 6.1 Entropy A System Property. 6.2 Retrieving Entropy Data. 6.3 Introducing the T dS Equations. 6.4 Entropy Change of an Incompressible Substance. 6.5 Entropy Change of an Ideal Gas. 6.6 Entropy Change in Internally Reversible Processes of Closed Systems. 6.7 Entropy Balance for Closed Systems. 6.8 Directionality of Processes. 6.9 Entropy Rate Balance for Control Volumes. Steady State Flow Processes. Chapter Summary and Study Guide. 7 Exergy Analysis. 7.1 Introducing Exergy. 7.2 Conceptualizing Exergy. 7.3 Exergy of a System. 7.4 Closed System Exergy Balance. 7.5 Exergy Rate Balance for Control Volumes at Steady State. 7.6 Exergetic (Second Law) Efficiency. 7.7 Thermoeconomics. Chapter Summary and Study Guide. 8 Vapor Power Systems. 8.1 Modeling Vapor Power Systems. 8.2 Analyzing Vapor Power Systems Rankine Cycle. 8.3 Improving Performance Superheat and Reheat. 8.4 Improving Performance Regenerative Vapor Power Cycle. 8.5 Other Vapor Cycle Aspects. 8.6 Case Study: Exergy Accounting of a Vapor Power Plant. Chapter Summary and Study Guide. 9 Gas Power Systems. Internal Combustion Engines. 9.1 Introducing Engine Terminology. 9.2 Air Standard Otto Cycle. 9.3 Air Standard Diesel Cycle. 9.4 Air Standard Dual Cycle. Gas Turbine Power Plants. 9.5 Modeling Gas Turbine Power Plants. 9.6 Air Standard Brayton Cycle. 9.7 Regenerative Gas Turbines. 9.8 Regenerative Gas Turbines with Reheat and Intercooling. 9.9 Gas Turbines for Aircraft Propulsion. 9.10 Combined Gas Turbine Vapor Power Cycle. Chapter Summary and Study Guide. 10 Refrigeration and Heat Pump Systems. 10.1 Vapor Refrigeration Systems. 10.2 Analyzing Vapor Compression Refrigeration Systems. 10.3 Refrigerant Properties. 10.4 Cascade and Multistage Vapor Compression Systems. 10.5 Absorption Refrigeration. 10.6 Heat Pump Systems. 10.7 Gas Refrigeration Systems. Chapter Summary and Study Guide. 11 Thermodynamic Relations. 11.1 Using Equations of State. 11.2 Important Mathematical Relations. 11.3 Developing Property Relations. 11.4 Evaluating Changes in Entropy, Internal Energy, and Enthalpy. 11.5 Other Thermodynamic Relations. 11.6 Constructing Tables of Thermodynamic Properties. Charts for Enthalpy and Entropy. 11.8 p v T Relations for Gas Mixtures. 11.9 Analyzing Multicomponent Systems. Chapter Summary and Study Guide. 12 Ideal Gas Mixture and Psychrometric Applications. Ideal Gas Mixtures: General Considerations. 12.1 Describing Mixture Composition. 12.2 Relating p, V, and T for Ideal Gas Mixtures. 12.3 Evaluating U, H, S, and Specific Heats. 12.4 Analyzing Systems Involving Mixtures. Psychrometric Applications. 12.5 Introducing Psychrometric Principles. 12.6 Psychrometers: Measuring the Wet Bulb and Dry Bulb Temperatures. 12.7 Psychrometric Charts. 12.8 Analyzing Air Conditioning Processes. 12.9 Cooling Towers. Chapter Summary and Study Guide. 13 Reacting Mixtures and Combustion. Combustion Fundamentals. 13.1 Introducing Combustion. 13.2 Conservation of Energy Reacting Systems. 13.3 Determining the Adiabatic Flame Temperature. 13.4 Fuel Cells. 13.5 Absolute Entropy and the Third Law of Thermodynamics. Chemical Exergy. 13.6 Introducing Chemical Exergy. 13.7 Standard Chemical Exergy. 13.8 Exergy Summary. 13.9 Exergetic (Second Law) Efficiencies of Reacting Systems. Chapter Summary and Study Guide. 14 Chemical and Phase Equilibrium. Equilibrium Fundamentals. 14.1 Introducing Equilibrium Criteria. Chemical Equilibrium. 14.2 Equation of Reaction Equilibrium. 14.3 Calculating Equilibrium Compositions. 14.4 Further Examples of the Use of the Equilibrium Constant. Phase Equilibrium. 14.5 Equilibrium Between Two Phases of a Pure Substance. 14.6 Equilibrium of Multicomponent, Multiphase Systems. Chapter Summary and Study Guide. Appendix Tables, Figures, and Charts. Index to Tables in SI Units. Index to Tables in English Units. Index to Figures and Charts. Index. Answers to Selected Problems: Visit the student.", "author_names": [ "Michael J Moran", "Howard N Shapiro" ], "corpus_id": 94324929, "doc_id": "94324929", "n_citations": 1680, "n_key_citations": 79, "score": 0, "title": "Fundamentals of Engineering Thermodynamics", "venue": "", "year": 2014 }, { "abstract": "From the Publisher: This book provides selective, in depth coverage of the fundamentals of software engineering by stressing principles and methods through rigorous formal and informal approaches. In contrast to other books which are based on the lifecycle model of software development, the authors emphasize identifying and applying fundamental principles that are applicable throughout the software lifecycle. This emphasis enables readers to respond to the rapid changes in technology that are common today. Principles and techniques are emphasized rather than specific toolsusers learn why particular techniques should or should not be used. Understanding the principles and techniques on which tools are based makes mastering a variety of specific tools easier. The authors discuss principles such as design, specification, verification, production, management and tools. Now coverage includes: more detailed analysis and explanation of object oriented techniques; the use of Unified Modeling Language (UML) requirements analysis and software architecture; Model checkinga technique that provides automatic support to the human activity of software verification; GQMused to evaluate software quality and help improve the software process; Z specification language. For software engineers.", "author_names": [ "Carlo Ghezzi", "Mehdi Jazayeri", "Dino Mandrioli" ], "corpus_id": 19080289, "doc_id": "19080289", "n_citations": 141, "n_key_citations": 10, "score": 0, "title": "Fundamentals of Software Engineering", "venue": "Lecture Notes in Computer Science", "year": 2011 } ]
Semiconductor devices fabricated from actinide oxides
[ { "abstract": "Abstract Recent investigations of the semiconductive properties of urania indicate that the oxides of uranium may be useful in the fabrication of certain active electronic devices. UO 2 and U 3 O 8 have been characterized as to their photo optical properties and active devices have been fabricated from urania.", "author_names": [ "Thomas T Meek", "Bolko von Roedern" ], "corpus_id": 95240832, "doc_id": "95240832", "n_citations": 22, "n_key_citations": 2, "score": 2, "title": "Semiconductor devices fabricated from actinide oxides", "venue": "", "year": 2008 }, { "abstract": "Abstract The electrical properties of the Cu/n InP and Al/n InP Schottky barrier diodes (SBDs) with and without the interfacial oxide layer have been investigated by using current voltage I V measurements. The oxide layer on chemically cleaned indium phosphide (InP) surface has been obtained by exposure to water vapor at 1 ml/min at 200 degC before metal evaporation. The chemical composition of surface oxides grown on the InP is investigated using X ray photoelectron spectroscopy (XPS) Phosphorus is present as In(PO 3 3 InPO 4 P 2 O 5 and P 4 O 10 The values of 0.437 0.007 and 0.438 0.003 eV for the barrier height of the reference Cu/n InP and Al/n InP SBDs were obtained, respectively. Furthermore, the values of 0.700 0.030 and 0.517 0.023 eV for the barrier height of the oxidized Cu/n InP and Al/n InP SBD were obtained, respectively. The transport properties of the metal semiconductor contacts have been observed to be significantly affected by the presence of the interfacial oxide layer. Devices built on the oxidized surfaces show improved characteristics compared with those built on chemically cleaned surfaces. The chemical reactivity of the metal with oxide and n InP is important to the formation of the Schottky barriers. The reactive metal Al gave a low barrier height due to the reduction of oxide and reaction with InP. The transmission coefficients for the oxidized Cu/n InP and Al/n InP are equal to 2.23 x 10 5 and 4.60 x 10 2 respectively.", "author_names": [ "Hidayet Cetin", "E Ayyildiz" ], "corpus_id": 96947233, "doc_id": "96947233", "n_citations": 28, "n_key_citations": 2, "score": 0, "title": "The electrical properties of metal oxide semiconductor devices fabricated on the chemically etched n InP substrate", "venue": "", "year": 2007 }, { "abstract": "Electronic memory cells are of critical importance in modern day computing devices, including emerging technology sectors such as large area printed electronics. One technology that has being receiving significant interest in recent years is resistive switching primarily due to its low dimensionality and nonvolatility. Here, we describe the development of resistive switching memory device arrays based on empty aluminum nanogap electrodes. By employing adhesion lithography, a low temperature and large area compatible nanogap fabrication technique, dense arrays of memory devices are demonstrated on both rigid and flexible plastic substrates. As prepared devices exhibit nonvolatile memory operation with stable endurance, resistance ratios $10^{4} and retention times of several months. An intermittent analysis of the electrode microstructure reveals that controlled resistive switching is due to migration of metal from the electrodes into the nanogap under the application of an external electric field. This alternative form of resistive random access memory is promising for use in emerging sectors such as large area electronics as well as in electronics for harsh environments, e.g. space, high/low temperature, magnetic influences, radiation, vibration, and pressure.", "author_names": [ "James Alexander Semple", "Gwenhivir Wyatt-Moon", "Dimitra G Georgiadou", "Martyn A McLachlan", "Thomas D Anthopoulos" ], "corpus_id": 38200638, "doc_id": "38200638", "n_citations": 14, "n_key_citations": 1, "score": 0, "title": "Semiconductor Free Nonvolatile Resistive Switching Memory Devices Based on Metal Nanogaps Fabricated on Flexible Substrates via Adhesion Lithography", "venue": "IEEE Transactions on Electron Devices", "year": 2017 }, { "abstract": "Device quality crystallographically oriented epitaxial (100)Ge and (110)Ge were grown on GaAs substrates using a large bandgap AlAs buffer. Electrical characteristics of p type metal oxide semiconductor (pMOS) capacitors, fabricated from the aforementioned material stacks, are presented for the first time. High resolution cross sectional transmission electron microscopy analysis demonstrated atomically abrupt heterointerfaces between Al<sub>2</sub>O<sub>3</sub>/Ge as well as Ge/AlAs for both (100) and (110) orientations. Various process conditions were implemented during MOS capacitor fabrication to study their impact on the Al<sub>2</sub>O<sub>3</sub>/Ge interface. The fabricated pMOS devices demonstrated excellent electrical characteristics with efficient modulation of the Fermi level from midgap to the conduction band edge, corresponding to a minimum <inline formula> <tex math notation=\"LaTeX\"{D}_{\\text {it} /tex math>/inline formula> value of <inline formula> <tex math notation=\"LaTeX\"{1.2} \\times {10}{11} /tex math>/inline formula> cm<inline formula> <tex math notation=\"LaTeX\" 2}\\cdot /tex math>/inline formula>ev<sup> 1</sup> on (100)Ge, indicative of a high quality oxide/Ge heterointerface, and an effective electrical passivation of the Ge surface. Postdeposition annealing under O<sub>2</sub> was found to be less effective at reducing oxide trap density <inline formula> <tex math notation=\"LaTeX\"{N}_{\\text {OT} /tex math>/inline formula> as compared to forming gas or O<sub>2</sub> postmetallization anneals (PMA) indicating that metal induced bandgap states at the gate metal/dielectric interface have a notable impact on Ge pMOS <inline formula> <tex math notation=\"LaTeX\"{N}_{\\text {OT} /tex math>/inline formula> On the other hand, a tradeoff must be made between <inline formula> <tex math notation=\"LaTeX\"{N}_{\\text {OT} /tex math>/inline formula> and the equivalent oxide thickness when performing PMA under O<sub>2</sub> or forming gas ambient.", "author_names": [ "Peter D Nguyen", "Michael B Clavel", "Jheng-Sin Liu", "Mantu K Hudait" ], "corpus_id": 10752967, "doc_id": "10752967", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Investigating FinFET Sidewall Passivation Using Epitaxial (100)Ge and (110)Ge Metal Oxide Semiconductor Devices on AlAs/GaAs", "venue": "IEEE Transactions on Electron Devices", "year": 2017 }, { "abstract": "Organic semiconductors make them interesting candidates for the development of innovative and disruptive applications also in large area and flexible sensor devices. In fact, organic based photoactive media combine effective light absorption in the region of the spectrum from ultraviolet to near infrared with good photogeneration yield and low temperature processability over large areas and on any substrate. Moreover, their electronic properties can be easily tuned to optimize, charges transport depending on the targeted application in the field of imaging, tactile or biomedical sensing. We made curved surface sensor array by thermal molding of planer device array on thin plastic film.", "author_names": [ "Kazuhiro Kudo", "Masatoshi Sakai" ], "corpus_id": 202561745, "doc_id": "202561745", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Flexible Information and Sensing Devices Fabricated by Printing Process", "venue": "2019 26th International Workshop on Active Matrix Flatpanel Displays and Devices (AM FPD)", "year": 2019 }, { "abstract": "The fabrication of both n and p type Si MOS capacitors using high k dielectric as insulator deposited by atomic layer deposition technique is presented. The interface obtained between the high k dielectric and the semiconductor substrate, critical for stability and feasibility of the experimental devices, is analyzed using both numerical calculation of the ideal capacitance voltage (C V) characteristics of the MOS capacitors and experimental data obtained at high frequency (500 kHz) Accordingly, the effective oxide charge is determined based on the deviation of the flat band voltage from the ideal value, the smallest value (7.3 x 1010 cm 2) being obtained for the HfO2/n Si structure. Using the Terman method, the interface traps density has been calculated, establishing that the HfO2/p type sample present the best interface on the entire range of energy level in Si band gap. Finally, the stability of the fabricated Si MOS capacitors is monitored by cyclically high frequency C V measurements with increased starting voltage after each recorded C V characteristic.", "author_names": [ "Razvan Pascu", "Pericle Varasteanu", "Mihaela Kusko", "Cosmin Romanitan", "Florin Nastase" ], "corpus_id": 42392665, "doc_id": "42392665", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Monitoring the stability of the fabricated high k Si MOS capacitors and investigation of the insulator/semiconductor interface", "venue": "2017 International Semiconductor Conference (CAS)", "year": 2017 }, { "abstract": "Micro Photoluminescence Imaging was used to identify the impact of thermal steps on dislocation density associated with Deep Trench Isolation. Previous work showed gate oxide failure due to slip associated with dislocations from the deep trenches. Micro Photoluminescence Imaging demonstrated capability to observe dislocation generation caused by thermally induced stress during processing of Deep Trench Isolation (DTI) wafers.", "author_names": [ "Bruce Greenwood", "Jeff P Gambino", "Y Watanabe", "Lubek Jastrzebski", "Gyorgy Nadudvari", "D'avid Cseh", "Laszlo Roszol", "Gyorgy Molnar", "Imre Lajtos" ], "corpus_id": 46978810, "doc_id": "46978810", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Micro photoluminescence imaging of dislocation generation in 0.18mm power semiconductor devices with deep trenches", "venue": "2018 29th Annual SEMI Advanced Semiconductor Manufacturing Conference (ASMC)", "year": 2018 }, { "abstract": "GaAs metal oxide semiconductor capacitors with NdTaON as gate dielectric and NdAlON, NdON or AlON as interfacial passivation layer (IPL) are fabricated, and their interfacial and electrical properties are compared with their counterpart without IPL. Experimental results show that owing to the suppressed hygroscopicity of NdON by Al incorporation, best improvements in electrical properties and reliability are achieved for the sample with NdAlON IPL (low interface state density <inline formula> <tex math notation=\"LaTeX\"$8 \\times 10^{11} /tex math>/inline formula> cm<sup> 2</sup>/eV) small flatband voltage (0.72 V) negligible hysteresis (43 mV) small frequency dispersion, and low gate leakage current density <inline formula> <tex math notation=\"LaTeX\"$2.56 \\times 10^ 6} /tex math>/inline formula> A/cm<sup>2</sup> at V<sub>fb</sub> 1 V) These should be attributed to suppressed growth of unstable Ga and As oxides on the GaAs surface and reduced in diffusion of elements from the gate dielectric to the GaAs surface by the NdAlON IPL during gate dielectric annealing.", "author_names": [ "L N Liu", "H W Choi", "J P Xu", "W M Tang", "Pui To Lai" ], "corpus_id": 9476388, "doc_id": "9476388", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "GaAs Metal Oxide Semiconductor Capacitor With Nd Based High k Oxynitrides as Gate Dielectric and Passivation Layer", "venue": "IEEE Transactions on Electron Devices", "year": 2018 }, { "abstract": "Recently, p type metal oxide semiconductors have attracted considerable interests for the applications in optoelectronic devices and low power complementary metal oxide semiconductor circuits. In this report, ternary p type CuAl<sub>x</sub>O<sub>y</sub> semiconductor thin films were fabricated by sol gel method and integrated as channel layers in thin film transistors (TFTs) The electrical performances of CuAl<sub>x</sub>O<sub>y</sub> TFTs, together with the characteristics of CuAl<sub>x</sub>O<sub>y</sub> thin films (e.g. crystalline phases, chemical compositions, surface morphology, and optical transmittances) were systematically studied at various annealing temperatures <inline formula> <tex math notation=\"LaTeX\"{T}_{a} /tex math>/inline formula> The phase pure CuAlO<sub>2</sub> thin films were obtained at <inline formula> <tex math notation=\"LaTeX\"{T}_{a} /tex math>/inline formula> above 800deg C in N<sub>2</sub> atmosphere. CuAlO<sub>2</sub> TFTs annealed at 900 deg C based on high k Al<sub>2</sub>O<sub>3</sub> exhibited optimized electrical performance, including a hole mobility of 1.36 cm<sub>2</sub>/Vs and on/off current ratio of <inline formula> <tex math notation=\"LaTeX\"\\sim 1 \\times 10^\\textsf {5} /tex math>/inline formula> This paper not only demonstrates the successful fabrication of high quality p type CuAlO<sub>2</sub> semiconductor thin film and electronic devices by sol gel process but also provides guidelines for related ternary p type oxide semiconductor material and device performance improvements.", "author_names": [ "Chunfeng Wang", "Haotian Zhu", "You Meng", "Shengbin Nie", "Yuna Zhao", "Byoung Chul Shin", "Elvira Fortunato", "Rodrigo Martins", "Fukai Shan", "Guoxia Liu" ], "corpus_id": 67874689, "doc_id": "67874689", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Sol Gel Processed p Type CuAlO2 Semiconductor Thin Films and the Integration in Transistors", "venue": "IEEE Transactions on Electron Devices", "year": 2019 }, { "abstract": "New platinum (Pt)/nickel oxide (NiO)/GaN based metal oxide semiconductor (MOS) diode type ammonia sensor was fabricated and studied. In addition, a new grey polynomial differential recovery (GPDR) model was developed for the application of data transmission. The studied Pt/NiO/GaN based MOS diode shows good ammonia sensing performance at relatively high temperatures <inline formula> <tex math notation=\"LaTeX\"\\ge 423$ /tex math>/inline formula> K) A very high sensing response of 244.2 under 1000 ppm NH<sub>3</sub>/air gas and a low detecting level of 2 ppm NH<sub>3</sub>/air are obtained at 423 K. The studied device also shows operating flexibility in the applied forward and reverse voltages, and good reversibility in ammonia sensing. In order to expand the practical application of ammonia sensing, a GPDR model was developed to effectively reduce <italic>data redundancy</italic> by 64.22% and achieve a recovery rate of 99.79% compared with the original data. Therefore, the studied sensor device provides promise for ammonia sensing applications.", "author_names": [ "I-Ping Liu", "Ching-Hong Chang", "Yen-Ming Huang", "Kun-Wei Lin" ], "corpus_id": 132798954, "doc_id": "132798954", "n_citations": 3, "n_key_citations": 2, "score": 0, "title": "On the Ammonia Sensing Performance and Transmission Approach of a Platinum/Nickel Oxide/GaN Based Metal Oxide Semiconductor Diode", "venue": "IEEE Journal of the Electron Devices Society", "year": 2019 } ]
4H--SiC step trench gate power metal--oxide--semiconductor field-effect transistor
[ { "abstract": "In this letter, an improved 4H SiC step trench gate power metal oxide semiconductor field effect transistor (MOSFET) with a p n junction in the trench is proposed. The step trench significantly reduces the ON resistance of the device. And the p n junction in the trench reduces the gate charge. Compared with the conventional p+ shielding trench MOSFET structure, simulation results show that the specific ON resistance and gate charge of the proposed device are improved by 26.4% and 34.7% respectively. A 43.4% improvement in the figure of merit (including the breakdown voltage and ON resistance) is also observed.", "author_names": [ "Ying Wang", "Kai Tian", "Yue Hao", "Cheng-Hao Yu", "Yan-juan Liu" ], "corpus_id": 9216415, "doc_id": "9216415", "n_citations": 20, "n_key_citations": 0, "score": 1, "title": "4H SiC Step Trench Gate Power Metal Oxide Semiconductor Field Effect Transistor", "venue": "IEEE Electron Device Letters", "year": 2016 }, { "abstract": "We report on the AlGaN/GaN metal oxide semiconductor heterostructure field effect transistor (MOS HFET) and present the results of the comparative studies of this device and a base line AlGaN/GaN heterostructure field effect transistor (HFET) For a 5 /spl mu/ source to drain opening, the maximum current was close to 600 mA/mm for both devices. The gate leakage current for the MOS HFET was more than six orders of magnitude smaller than for the HFET.", "author_names": [ "M A Khan", "X Hu", "Guo Sumin", "Alexander V Lunev", "Jiangyong Yang", "Remigijus Gaska", "Michael S Shur" ], "corpus_id": 22633371, "doc_id": "22633371", "n_citations": 346, "n_key_citations": 6, "score": 0, "title": "AlGaN/GaN metal oxide semiconductor heterostructure field effect transistor", "venue": "IEEE Electron Device Letters", "year": 2000 }, { "abstract": "Fundamentals of Power Semiconductor Devices provides an in depth treatment of the physics of operation of power semiconductor devices that are commonly used by the power electronics industry. Analytical models for explaining the operation of all power semiconductor devices are shown. The treatment focuses on silicon devicesandincludes the unique attributes and design requirements for emerging silicon carbide devices.", "author_names": [ "B Jayant Baliga" ], "corpus_id": 221005416, "doc_id": "221005416", "n_citations": 1262, "n_key_citations": 105, "score": 0, "title": "Fundamentals of Power Semiconductor Devices", "venue": "", "year": 2008 }, { "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": 0, "title": "A Survey of Wide Bandgap Power Semiconductor Devices", "venue": "IEEE Transactions on Power Electronics", "year": 2014 }, { "abstract": "I. SEMICONDUCTOR FUNDAMENTALS. 1. Semiconductors A General Introduction. General Material Properties. Crystal Structure. Crystal Growth. 2. Carrier Modeling. The Quantization Concept. Semiconductor Models. Carrier Properties. State and Carrier Distributions. Equilibrium Carrier Concentrations. 3. Carrier Action. Drift. Diffusion. Recombination Generation. Equations of State. Supplemental Concepts. 4. Basics of Device Fabrication. Fabrication Processes. Device Fabrication Examples. R1. Part I Supplement and Review. Alternative/Supplemental Reading List. Figure Sources/Cited References. Review List of Terms. Part I Review Problem Sets and Answers. IIA. PN JUNCTION DIODES. 5. PN Junction Electrostatics. Preliminaries. Quantitative Electrostatic Relationships. 6. PN Junction Diode I V Characteristics. The Ideal Diode Equation. Deviations from the Ideal. Special Considerations. 7. PN Junction Diode Small Signal Admittance. Introduction. Reverse Bias Junction Capacitance. Forward Bias Diffusion Admittance. 8. PN Junction Diode Transient Response. Turn Off Transient. Turn On Transient. 9. Optoelectronic Diodes. Introduction. Photodiodes. Solar Cells. LEDs. IIB. BJTS AND OTHER JUNCTION DEVICES. 10. BJT Fundamentals. Terminology. Fabrication. Electrostatics. Introductory Operational Considerations. Performance Parameters. 11. BJT Static Characteristics. Ideal Transistor Analysis. Deviations from the Ideal. Modern BJT Structures. 12. BJT Dynamic Response Modeling. Equivalent Circuits. Transient (Switching) Response. 13. PNPN Devices. Silicon Controlled Rectifier (SCR) SCR Operational Theory. Practical Turn on/Turn off Considerations. Other PNPN Devices. 14. MS Contacts and Schottky Diodes. Ideal MS Contacts. Schottky Diode. Practical Contact Considerations. R2. Part II Supplement and Review. Alternative/Supplemental Reading List. Figure Sources/Cited References. Review List of Terms. Part II Review Problem Sets and Answers. III. FIELD EFFECT DEVICES. 15. Field Effect Introduction the J FET and MESFET. General Introduction. J FET. MESFET. 16. MOS Fundamentals. Ideal Structure Definition. Electrostatics Mostly Qualitative. Electrostatics Quantitative Formulation. Capacitance Voltage Characteristics. 17. MOSFETs The Essentials. Qualitative Theory of Operation. Quantitative ID VD Relationships. ac Response. 18. Nonideal MOS. Metal Semiconductor Workfunction Difference. Oxide Charges. MOSFET Threshold Considerations. 19. Modern FET Structures. Small Dimension Effects. Select Structure Survey. R3. Part III Supplement and Review. Alternative/Supplemental Reading List. Figure Sources/Cited References. Review List of Terms. Part III Review Problem Sets and Answers. Appendix A. Elements of Quantum Mechanics. Appendix B. MOS Semiconductor Electrostatics Exact Solution. Appendix C. MOS C V Supplement. Appendix D. MOS I Vsupplement. Appendix E. List of Symbols. Appendix M. MATLAB Program Script.", "author_names": [ "Robert F Pierret" ], "corpus_id": 60043407, "doc_id": "60043407", "n_citations": 1008, "n_key_citations": 68, "score": 0, "title": "Semiconductor device fundamentals", "venue": "", "year": 1996 }, { "abstract": "Lateral metal oxide semiconductor field effect transistors (MOSFETs) have been fabricated on 4H SiC utilizing deposited dielectrics and gate last processing. The bilayer dielectric consists of thin nitrided SiO2 covered by 25 nm of Al2O3 deposited using atomic layer deposition. Field effect mobility and threshold voltage (VT) vary with SiC nitric oxide (NO) anneal temperature. Peak mobility of 106 cm2/Vs was obtained with corresponding VT of 0.8 V. The peak mobility decreases to 61 cm2/Vs with a lower temperature NO anneal, while the VT increased to 1.4 V. Thus with proper gate engineering, high mobility normally off MOSFET devices can be obtained, leading to higher performance gate controlled power devices.", "author_names": [ "Daniel J Lichtenwalner", "Veena Misra", "Sarit Dhar", "Sei-hyung Ryu", "Anant K Agarwal" ], "corpus_id": 121493327, "doc_id": "121493327", "n_citations": 39, "n_key_citations": 0, "score": 0, "title": "High mobility enhancement mode 4H SiC lateral field effect transistors utilizing atomic layer deposited Al2O3 gate dielectric", "venue": "", "year": 2009 }, { "abstract": "Results presented in this letter demonstrate that the effective channel mobility of lateral, inversion mode 4H SiC MOSFETs is increased significantly after passivation of SiC/SiO/sub 2/ interface states near the conduction band edge by high temperature anneals in nitric oxide. Hi lo capacitance voltage (C V) and ac conductance measurements indicate that, at 0.1 eV below the conduction band edge, the interface trap density decreases from approximately 2/spl times/10/sup 13/ to 2/spl times/10/sup 12/ eV/sup 1/ cm/sup 2/ following anneals in nitric oxide at 1175/spl deg/C for 2 h. The effective channel mobility for MOSFETs fabricated with either wet or dry oxides increases by an order of magnitude to approximately 30 35 cm/sup 2//V s following the passivation anneals.", "author_names": [ "Gil Yong Chung", "Chin-Che Tin", "J R Williams", "K McDonald", "Ravi Chanana", "Robert A Weller", "Sokrates T Pantelides", "L C Feldman", "Orin Wayne Holland", "Mrinal K Das", "John W Palmour" ], "corpus_id": 20679413, "doc_id": "20679413", "n_citations": 488, "n_key_citations": 9, "score": 0, "title": "Improved inversion channel mobility for 4H SiC MOSFETs following high temperature anneals in nitric oxide", "venue": "IEEE Electron Device Letters", "year": 2001 }, { "abstract": "SiC JFET, compared with SiC MOSFET, is attractive for high power, high temperature applications because it is free of gate oxide reliability issues. Trenched and Implanted VJFET (TIVJFET) does not require epi regrowth and is capable of high current density. In this work we demonstrate two trenched and implanted normally off 4H SiC vertical junction field effect transistors (TI VJFET) based on 120mm, 4.9x1014cm 3 and 100mm, 6x1014cm 3 drift layers. The corresponding devices showed blocking voltage (VB) of 11.1kV and specific on resistance (RSP_ON) of 124m7cm2, and VB of 10kV and RSP_ON of 87m7cm2. A record high value for VB 2/RSP_ON of 1149MW/cm2 was achieved for normally off SiC FETs.", "author_names": [ "Yu Zhu Li", "Petre Alexandrov", "Jianhui Zhang", "Larry X Li", "Jian H Zhao" ], "corpus_id": 45339239, "doc_id": "45339239", "n_citations": 8, "n_key_citations": 1, "score": 0, "title": "10 kV, 87 mOcm2 Normally Off 4H SiC Vertical Junction Field Effect Transistors", "venue": "", "year": 2006 }, { "abstract": "4H silicon carbide (SiC) normally off vertical junction field effect transistor (JFET) is developed in a purely vertical configuration without internal lateral JFET gates. The 2.1 /spl mu/m vertical p/sup /n junction gates are created on the side walls of deep trenches by tilted aluminum (Al) implantation. Normally off operation with blocking voltage V/sub bl/ of 1 726 V is demonstrated with an on state current density of 300 A/cm/sup 2/ at a drain voltage of 3 V. The low specific on resistance R/sub on sp/ of 3.6 m/spl Omega/cm/sup 2/ gives the V/sub bl//sup 2//R/sub on sp/ value of 830 MW/cm/sup 2/ surpassing the past records of both unipolar and bipolar 4H SiC power switches.", "author_names": [ "Kiyoshi Tone", "J H Zhao", "Leonid Fursin", "Petre Alexandrov", "Maurice Weiner" ], "corpus_id": 642587, "doc_id": "642587", "n_citations": 67, "n_key_citations": 11, "score": 0, "title": "4H SiC normally off vertical junction field effect transistor with high current density", "venue": "IEEE Electron Device Letters", "year": 2003 }, { "abstract": "This letter reports the demonstration of a 4H SiC trenched and implanted vertical junction field effect transistor (TI VJFET) The p/sup /n junction gates are created on the sidewalls of deep trenches by angled Al implantation, which eliminates the need for epitaxial regrowth during the JFET fabrication. Blocking voltages up to 1710 V has been achieved with a voltage supporting drift layer of only 9.5 /spl mu/m by using a two step junction termination extension. The TI VJFET shows a low specific on resistance R/sub ON sp/ of 2.77m/spl Omega/cm/sup 2/ corresponding to a record high value of V/sub B//R/sub ON sp/ equal to 1056 MW/cm/sup 2/", "author_names": [ "J H Zhao", "Kiyoshi Tone", "Petre Alexandrov", "Leonid Fursin", "Maurice Weiner" ], "corpus_id": 19090715, "doc_id": "19090715", "n_citations": 25, "n_key_citations": 1, "score": 0, "title": "1710 V 2.77 m/spl Omega/cmsub 2 4H SiC trenched and implanted vertical junction field effect transistors", "venue": "IEEE Electron Device Letters", "year": 2003 } ]
machine learning semiconductor thermal
[ { "abstract": "Variability is a problem for the scalability of semiconductor quantum devices. The parameter space is large, and the operating range is small. Our statistical tuning algorithm searches for specific electron transport features in gate defined quantum dot devices with a gate voltage space of up to eight dimensions. Starting from the full range of each gate voltage, our machine learning algorithm can tune each device to optimal performance in a median time of under 70 minutes. This performance surpassed our best human benchmark (although both human and machine performance can be improved) The algorithm is approximately 180 times faster than an automated random search of the parameter space, and is suitable for different material systems and device architectures. Our results yield a quantitative measurement of device variability, from one device to another and after thermal cycling. Our machine learning algorithm can be extended to higher dimensions and other technologies. To optimize operating conditions of large scale semiconductor quantum devices, a large parameter space has to be explored. Here, the authors report a machine learning algorithm to navigate the entire parameter space of gate defined quantum dot devices, showing about 180 times faster than a pure random search.", "author_names": [ "H Moon", "Dominic T Lennon", "J Kirkpatrick", "N M van Esbroeck", "Leon C Camenzind", "Liuqi Yu", "Florian Vigneau", "Dominik M Zumbuhl", "G Andrew D Briggs", "Michael A Osborne", "D Sejdinovic", "E A Laird", "Natalia Ares" ], "corpus_id": 210064645, "doc_id": "210064645", "n_citations": 23, "n_key_citations": 2, "score": 0, "title": "Machine learning enables completely automatic tuning of a quantum device faster than human experts", "venue": "Nature Communications", "year": 2020 }, { "abstract": "Power chips such as Metal Oxide Field Effect Transistors (MOSFETs) are widely used and can be found in many electronics and electrical products. The ability to predict the degradation of such power electronic devices can minimise the risk of their failure during operation and support maintenance planning operations. In this study, a data driven prognostics approach using system identification and machine learning modelling technique is developed and used to predict the time to failure of MOSFET TO 220 packages associated with delamination failure mode of the die attachment. Run to failure data under thermal overstress loading conditions for power chip devices, available from the NASA Prognostics Centre data repository, is used to develop a data driven prognostic model that can be used to predict the time to failure (TtF) of power MOSFETs under accelerated test loads. An increment in ON state resistance of the MOSFET is used as precursor for device failure through die attach degradation. Results from this research show that when monitored data from a damage indicator for a particular failure mode of an electronic package changes dynamically, data driven modelling using engineering control techniques such as State Space representation is capable of producing reliable, multi step ahead predictions for the time to failure of the device.", "author_names": [ "Mominul Ahsan", "Stoyan Stoyanov", "Chris Bailey" ], "corpus_id": 52129477, "doc_id": "52129477", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Data Driven Prognostics for Failure of Power Semiconductor Packages", "venue": "2018 41st International Spring Seminar on Electronics Technology (ISSE)", "year": 2018 }, { "abstract": "Abstract Plasma enhanced atomic layer deposition (PEALD) is one of the most widely adopted deposition methods used in the semiconductor industry. It is chosen largely due to its superior ability to produce ultra thin high k dielectric films, which are needed for the further miniaturization of microelectronic devices with the pace of Moore's Law. In contrast to the traditional thermal atomic layer deposition (ALD) method, PEALD allows for high deposition growth per cycle (GPC) under low operating temperature with the help of high energy plasma species. Despite the experimental effort in finding new precursors and plasmas, the detailed surface structures and reaction mechanisms in various PEALD processes remain hard to understand because of the limitation of current in situ monitoring techniques and the deficiency of the first principles based analysis. Therefore, in this work, an accurate, yet efficient kinetic Monte Carlo (kMC) model and an associated machine learning (ML) analysis are proposed to capture the surface deposition mechanism and to propose optimal operating conditions of the HfO2 thin film PEALD using tetrakis dimethylamino Hafnium (TDMAHf) and oxygen plasma. Density Functional Theory (DFT) calculations are performed to obtain the key kinetic parameters and the structural details, subsequently employed in the kMC model. After the kMC model is validated by experimental data, a database is generated to explore a variety of precursor partial pressure and substrate temperature combinations using the kMC algorithm. A feed forward Bayesian regularized artificial neural network (BRANN) is then constructed to characterize the input output relationship and to investigate the optimal operating conditions.", "author_names": [ "Yangyao Ding", "Yichi Zhang", "Gerassimos Orkoulas", "Panagiotis D Christofides" ], "corpus_id": 219496491, "doc_id": "219496491", "n_citations": 5, "n_key_citations": 1, "score": 1, "title": "Microscopic modeling and optimal operation of plasma enhanced atomic layer deposition", "venue": "", "year": 2020 }, { "abstract": "As the micro electro mechanical machine (MEMS) industry is maturing, an increased array of product applications and devices are being introduced. As these devices are being developed new processes are required to control and attain the desired levels of polysilicon stress. In this work the relationship between polysilicon blanket residual stress and dopant concentration and anneal conditions are investigated. It was found that as the sheet resistance increased, the magnitude of the stress increased several orders of magnitude. Annealing the wafers for increased durations and multiple cycles lowered the level of stress observed while reducing the response to dopant concentration. The response was reduced by fifty percent for a time increase from 20 to 180 minutes. It is suggested that specific levels of stress are best attained with modifications to the dopant concentration for the required thermal cycles. The characterization performed allows for reduced learning cycles and cost in the development of new MEMS process flows to achieve first pass success for device specific requirements.", "author_names": [ "Jerzy Woloszyn" ], "corpus_id": 29987722, "doc_id": "29987722", "n_citations": 5, "n_key_citations": 0, "score": 2, "title": "A method for controlling residual film stress in LPCVD polysilicon films for surface micromachined MEMS", "venue": "2004 IEEE/SEMI Advanced Semiconductor Manufacturing Conference and Workshop (IEEE Cat. No.04CH37530)", "year": 2004 }, { "abstract": "While spin qubits based on gate defined quantum dots have demonstrated very favorable properties for quantum computing, one remaining hurdle is the need to tune each of them into a good operating regime by adjusting the voltages applied to electrostatic gates. The automation of these tuning procedures is a necessary requirement for the operation of a quantum processor based on gate defined quantum dots, which is yet to be fully addressed. We present an algorithm for the automated fine tuning of quantum dots, and demonstrate its performance on a semiconductor singlet triplet qubit in GaAs. The algorithm employs a Kalman filter based on Bayesian statistics to estimate the gradients of the target parameters as function of gate voltages, thus learning the system response. The algorithm's design is focused on the reduction of the number of required measurements. We experimentally demonstrate the ability to change the operation regime of the qubit within 3 to 5 iterations, corresponding to 10 to 15 minutes of lab time.", "author_names": [ "Julian D Teske", "Simon Sebastian Humpohl", "Ren'e Otten", "Patrick Bethke", "Pascal Cerfontaine", "Jonas Dedden", "Arne Ludwig", "Andreas Dirk Wieck", "Hendrik Bluhm" ], "corpus_id": 117683624, "doc_id": "117683624", "n_citations": 28, "n_key_citations": 1, "score": 0, "title": "A machine learning approach for automated fine tuning of semiconductor spin qubits", "venue": "Applied Physics Letters", "year": 2019 }, { "abstract": "Understanding the breakdown mechanisms of polymer based dielectrics is critical to achieving high density energy storage. Here a comprehensive phase field model is developed to investigate the electric, thermal, and mechanical effects in the breakdown process of polymer based dielectrics. High throughput simulations are performed for the P(VDF HFP) based nanocomposites filled with nanoparticles of different properties. Machine learning is conducted on the database from the high throughput simulations to produce an analytical expression for the breakdown strength, which is verified by targeted experimental measurements and can be used to semiquantitatively predict the breakdown strength of the P(VDF HFP) based nanocomposites. The present work provides fundamental insights to the breakdown mechanisms of polymer nanocomposite dielectrics and establishes a powerful theoretical framework of materials design for optimizing their breakdown strength and thus maximizing their energy storage by screening suitable nanofillers. It can potentially be extended to optimize the performances of other types of materials such as thermoelectrics and solid electrolytes.Polymer dielectrics are promising for high density energy storage but dielectric breakdown is poorly understood. Here, a phase field model is developed to investigate electric, thermal, and mechanical effects in the breakdown process for a range of polymer dielectrics, and analytical expression for breakdown strength is provided by machine learning.", "author_names": [ "Zhonghui Shen", "Jian-Jun Wang", "Jian-yong Jiang", "Sharon X Huang", "Yuanhua Lin", "Ce-Wen Nan", "Long-Qing Chen", "Yang Shen" ], "corpus_id": 128362091, "doc_id": "128362091", "n_citations": 68, "n_key_citations": 0, "score": 0, "title": "Phase field modeling and machine learning of electric thermal mechanical breakdown of polymer based dielectrics", "venue": "Nature Communications", "year": 2019 }, { "abstract": "Abstract This work introduces a new technique that provides real time feedback to a Heating, Ventilation, and Air Conditioning (HVAC) system controller with respect to the occupants' thermal preferences to avoid space overheating. We propose a non invasive approach for automatic prediction of personal thermal comfort and mean time to warm discomfort using machine learning. The prediction framework described uses temperature information extracted from multiple local body parts to model an individual's thermal preference, with sensing measurements that capture local body part variance as well as differences between body parts. We compared the efficacy of using machine learning with classical measurements such as skin temperature along with our approach of using multi part measurements and derived data. An analysis of the performance of machine learning shows that our method improved the accuracy of personal thermal comfort prediction by an average of 60% and the accuracy of mean time to warm discomfort prediction by an average of 40% The proposed thermal models were tested on subjects' data extracted from an office setup with room temperature varying from low (21.11 degC) to high (27.78 degC) When all proposed features were used, personal thermal comfort was predicted with an accuracy higher than 80% and mean time to warm discomfort with more than 85% accuracy. Further analysis of the machine learning efficacy showed that temperature differences had the highest impact on performance of individual thermal preference prediction, while the proposed approach was found not sensitive to the actual machine learning algorithm.", "author_names": [ "Andrei Claudiu Cosma", "Rahul Simha" ], "corpus_id": 91181200, "doc_id": "91181200", "n_citations": 37, "n_key_citations": 0, "score": 0, "title": "Machine learning method for real time non invasive prediction of individual thermal preference in transient conditions", "venue": "", "year": 2019 }, { "abstract": "Abstract Thermal fluid processes are inherently multi physics and multi scale, involving mass momentum energy transport phenomena at multiple scales. Thermal fluid simulation (TFS) is based on solving conservative equations, for which except for \"first principles\" direct numerical simulation closure relations (CRs) are required to provide microscopic interactions or so called sub grid scale physics. In practice, TFS is realized through reduced order modeling, and its CRs as low fidelity models can be informed by observations and data from relevant and adequately evaluated experiments and high fidelity simulations. This paper is focused on data driven TFS models, specifically on their development using machine learning (ML) Five ML frameworks are introduced including physics separated ML (PSML or Type I ML) physics evaluated ML (PEML or Type II ML) physics integrated ML (PIML or Type III ML) physics recovered (PRML or Type IV ML) and physics discovered ML (PDML or Type V ML) The frameworks vary in their performance for different applications depending on the level of knowledge of governing physics, source, type, amount and quality of available data for training. Notably, outlined for the first time in this paper, Type III models present stringent requirements on modeling, substantial computing resources for training, and high potential in extracting value from \"big data\" in thermal fluid research. The current paper demonstrates and investigates ML frameworks in three examples. First, we utilize the heat diffusion equation with a nonlinear conductivity model formulated by convolutional neural networks (CNNs) and feedforward neural networks (FNNs) to illustrate the applications of Type I, Type II, Type III, and Type V ML. The results indicate a preference for Type II ML under deficient data support. Type III ML can effectively utilize field data, potentially generating more robust predictions than Type I and Type II ML. CNN based closures exhibit more predictability than FNN based closures, but CNN based closures require more training data to obtain accurate predictions. Second, we illustrate how to employ Type I ML and Type II ML frameworks for data driven turbulence modeling using reference works. Third, we demonstrate Type I ML by building a deep FNN based slip closure for two phase flow modeling. The results show that deep FNN based closures exhibit a bounded error in the prediction domain.", "author_names": [ "Chih-Wei Chang", "Nam T Dinh" ], "corpus_id": 4954624, "doc_id": "4954624", "n_citations": 31, "n_key_citations": 3, "score": 0, "title": "Classification of machine learning frameworks for data driven thermal fluid models", "venue": "", "year": 2019 }, { "abstract": "The use of machine learning in computational molecular design has great potential to accelerate the discovery of innovative materials. However, its practical benefits still remain unproven in real world applications, particularly in polymer science. We demonstrate the successful discovery of new polymers with high thermal conductivity, inspired by machine learning assisted polymer chemistry. This discovery was made by the interplay between machine intelligence trained on a substantially limited amount of polymeric properties data, expertise from laboratory synthesis and advanced technologies for thermophysical property measurements. Using a molecular design algorithm trained to recognize quantitative structure property relationships with respect to thermal conductivity and other targeted polymeric properties, we identified thousands of promising hypothetical polymers. From these candidates, three were selected for monomer synthesis and polymerization because of their synthetic accessibility and their potential for ease of processing in further applications. The synthesized polymers reached thermal conductivities of 0.18 0.41 W/mK, which are comparable to those of state of the art polymers in non composite thermo plastics.", "author_names": [ "Stephen Wu", "Yukiko Kondo", "Masa-aki Kakimoto", "Bin Yang", "Hironao Yamada", "Isao Kuwajima", "Guillaume Lambard", "Kenta Hongo", "Yibin Xu", "Junichiro Shiomi", "Christoph Schick", "Junko Morikawa", "Ryo Yoshida" ], "corpus_id": 197591784, "doc_id": "197591784", "n_citations": 78, "n_key_citations": 0, "score": 0, "title": "Machine learning assisted discovery of polymers with high thermal conductivity using a molecular design algorithm", "venue": "npj Computational Materials", "year": 2019 }, { "abstract": "Various factors affect the interfacial thermal resistance (ITR) between two materials, making ITR prediction a high dimensional mathematical problem. Machine learning is a cost effective method to address this. Here, we report ITR predictive models based on experimental data. The physical, chemical, and material properties of ITR are categorized into three sets of descriptors, and three algorithms are used for the models. Those descriptors assist the models in reducing the mismatch between predicted and experimental values and reaching high predictive performance of 96% Over 80,000 material systems composed of 293 materials were inputs for predictions. Among the top 100 high ITR predictions by the three different algorithms, 25 material systems are repeatedly predicted by at least two algorithms. One of the 25 material systems, Bi/Si achieved the ultra low thermal conductivity in our previous work. We believe that the predicted high ITR material systems are potential candidates for thermoelectric applications. This study proposed a strategy for material exploration for thermal management by means of machine learning.", "author_names": [ "Yen-Ju Wu", "Lei Fang", "Yibin Xu" ], "corpus_id": 155555921, "doc_id": "155555921", "n_citations": 35, "n_key_citations": 1, "score": 0, "title": "Predicting interfacial thermal resistance by machine learning", "venue": "npj Computational Materials", "year": 2019 } ]
Perovskite photonic sources Nature Photonics
[ { "abstract": "The prospects for light emitting diodes and lasers based on perovskite materials are reviewed. The field of solution processed semiconductors has made great strides; however, it has yet to enable electrically driven lasers. To achieve this goal, improved materials are required that combine efficient >50% quantum yield) radiative recombination under high injection, large and balanced charge carrier mobilities in excess of 10 cm2 V 1 s 1, free carrier densities greater than 1017 cm 3 and gain coefficients exceeding 104 cm 1. Solid state perovskites are in addition to galvanizing the field of solar electricity showing great promise in photonic sources, and may be the answer to realizing solution cast laser diodes. Here, we discuss the properties of perovskites that benefit light emission, review recent progress in perovskite electroluminescent diodes and optically pumped lasers, and examine the remaining challenges in achieving continuous wave and electrically driven lasing.", "author_names": [ "Brandon R Sutherland", "Edward H Sargent" ], "corpus_id": 53449307, "doc_id": "53449307", "n_citations": 883, "n_key_citations": 3, "score": 1, "title": "Perovskite photonic sources", "venue": "", "year": 2016 }, { "abstract": "Miniaturized photonic sources based on semiconducting two dimensional (2D) materials offer new technological opportunities beyond the modern III V platforms. For example, the quantum confined 2D electronic structure aligns the exciton transition dipole moment parallel to the surface plane, thereby outcoupling more light to air which gives rise to high efficiency quantum optics and electroluminescent devices. It requires scalable materials and processes to create the decoupled multi quantum well superlattices, in which individual 2D material layers are isolated by atomically thin quantum barriers. Here, we report decoupled multi quantum well superlattices comprised of the colloidal quantum wells of lead halide perovskites, with unprecedentedly ultrathin quantum barriers that screen interlayer interactions within the range of 6.5 A. Crystallographic and 2D k space spectroscopic analysis reveals that the transition dipole moment orientation of bright excitons in the superlattices is predominantly in plane and independent of stacking layer and quantum barrier thickness, confirming interlayer decoupling. Decoupled high order MQW superlattices are desired to design miniaturized photonic sources but they are yet to be realized in scalable ways. Here Jagielski et al achieve this goal using multiple stacked colloidal lead halide perovskite quantum wells separated by atomically thin quantum barriers.", "author_names": [ "Jakub Jagielski", "Simon F Solari", "Lucie Jordan", "Declan Scullion", "Balthasar Blulle", "Yen-Ting Li", "Frank Krumeich", "Yu-Cheng Chiu", "Beat Ruhstaller", "Elton J G Santos", "Chih-Jen Shih" ], "corpus_id": 210716055, "doc_id": "210716055", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Scalable photonic sources using two dimensional lead halide perovskite superlattices", "venue": "Nature Communications", "year": 2020 }, { "abstract": "The fluorescence intensity and spontaneous emission rate of perovskite quantum dots with different emission wavelength are enhanced by monolithic hyperbolic metamaterials, which provides a powerful way for monolithic integrated high frequency, high brightness perovskite multicolor photonic sources.", "author_names": [ "Feiliang Chen", "Qian Li", "Mo Li", "Hui Zhang", "Feng Huang", "Shuxiao Li", "Jian Zhang" ], "corpus_id": 126074222, "doc_id": "126074222", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Monolithic Integrated High Frequency, High Brightness Perovskite Quantum Dots Multicolor Photonic Sources Coupled with Hyperbolic Metamaterials", "venue": "2018 Conference on Lasers and Electro Optics Pacific Rim (CLEO PR)", "year": 2018 }, { "abstract": "Metal halide perovskites are promising lasing materials for the realization of monolithically integrated laser sources, the key components of silicon photonic integrated circuits (PICs) Perovskites can be deposited from solution and require only low temperature processing, leading to significant cost reduction and enabling new PIC architectures compared to state of the art lasers realized through the costly and inefficient hybrid integration of III V semiconductors. Until now, however, due to the chemical sensitivity of perovskites, no microfabrication process based on optical lithography (and, therefore, on existing semiconductor manufacturing infrastructure) has been established. Here, the first methylammonium lead iodide perovskite microdisc lasers monolithically integrated into silicon nitride PICs by such a top down process are presented. The lasers show a record low lasing threshold of 4.7 mJcm 2 at room temperature for monolithically integrated lasers, which are complementary metal oxide semiconductor compatible and can be integrated in the back end of line processes.", "author_names": [ "Piotr J Cegielski", "Anna Lena Giesecke", "Stefanie Neutzner", "C Porschatis", "Marina Gandini", "Daniel Schall", "Carlo Andrea Riccardo Perini", "Jens Bolten", "Stephan Suckow", "Satender Kataria", "Bartos Chmielak", "T Wahlbrink", "Annamaria Petrozza", "Max Christian Lemme" ], "corpus_id": 206749400, "doc_id": "206749400", "n_citations": 44, "n_key_citations": 0, "score": 0, "title": "Monolithically Integrated Perovskite Semiconductor Lasers on Silicon Photonic Chips by Scalable Top Down Fabrication.", "venue": "Nano letters", "year": 2018 }, { "abstract": "The first part of this thesis focuses on a novel design of photonic crystal microcavity coupled to InGaAs quantum dots. Such coupled dot cavity systems can be used as enhanced single photon sources for quantum information applications and more complicated arrangements could even be used as optical switches in a quantum computer. A photolithography process is used to fabricate these cavities, allowing them to overcome many of the difficulties involved in achieving reliable dot cavity coupling in traditional e beam defined cavities. Theoretical FDTD simulations are used to predict the Q factor and mode volume (1.44 (l0/n)3) of this cavity design. The fabrication process is given in detail, and micro photoluminescence measurements are used to verify successful cavity fabrication. A success rate of 85% is achieved with Q factors as high as 7.4 x 103 at a wavelength of around 1.25 um. These cavities are shown to have comparable performance to existing designs such as L3 and Notomi cavities fabricated using e beam lithography. The second part covers studies of four different polycrystalline perovskite films with compositions of the form FA0.83Cs0.17Pb(BrxI1 x)3 and varying bromine fraction x {0.1, 0.2, 0.3, 0.4} These perovskites are promising candidates for commercially scalable photovoltaic applications and have received a great deal of scientific interest over the past decade. This particular composition has been shown to have improved stability and optoelectronic properties compared to other perovskites. Micro photoluminescence mapping is used to study the temperature dependence and structure of these samples. The diffusion lengths are found to be in the range from 2 um to 5 um, and evidence of photon recycling over longer distances is identified. Time resolved photoluminescence measurements are carried out at cryogenic temperatures to study the carrier decay dynamics. A theoretical model of the decay process is developed and fitted to the data. Both excitons and free carriers are found to contribute to the emission, with the 10% bromine sample having the highest exciton binding energy.", "author_names": [ "Luke P Nuttall" ], "corpus_id": 210802446, "doc_id": "210802446", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Scanning micro photoluminescence studies of GaAs photonic crystals and perovskite structures", "venue": "", "year": 2019 }, { "abstract": "Influence of the nature of A cation on dynamics of charge transfer processes in perovskite solar cells Pankaj Yadav, Mohammad Alotaibi, Neha Arora, M. Ibrahim Dar, Shaik Mohammed Zakeeruddin, and Michael Gratzel Dr. P. Yadav, Dr. N. Arora, Dr. M. I. Dar, Dr. S. M. Zakeeruddin, Prof. M. Gratzel Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Federale de Lausanne, CH 1015 Lausanne, Switzerland. Dr. M. Alotaibi National Nanotechnology center, King Abdulaziz city for science and technology, Riyadh, Saudi Arabia. E mail: ibrahim.dar@epfl.ch +P.Y. and M.A. contributed equally to this work.", "author_names": [ "Pankaj Yadav", "Mohammad Hayal Alotaibi", "Neha Arora", "M Ibrahim Dar", "Shaik Mohammed Zakeeruddin", "Michael Gratzel" ], "corpus_id": 103567823, "doc_id": "103567823", "n_citations": 37, "n_key_citations": 0, "score": 0, "title": "Influence of the Nature of A Cation on Dynamics of Charge Transfer Processes in Perovskite Solar Cells", "venue": "", "year": 2018 }, { "abstract": "Here we design photonic nanostructures for perovskite thin film of CH3NH3PbI3 (MAPbI3) Optical properties of perovskite thin film are reported with the emission spectra peaked at 765 nm with FWHM of 50 nm. Based on the experimentally obtained optical constants, two dimensional perovskite photonic crystals are designed through plane wave expansion and finite element methods. The calculated band structure of 2D photonic crystal slab shows the photonic band gap at 750 800 nm, originated from the x y plane wave excitation. Incorporating one hole and three hole missing cavities in the photonic crystal slabs generates one and two modes in electric field spectra, respectively, indicating that the one hole missing cavity is more efficient for low power consumption of light source devices.", "author_names": [ "L J Diguna", "Hendradi Hardhienata", "", "Muhammad Danang Birowosuto" ], "corpus_id": 155990205, "doc_id": "155990205", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Design of perovskite photonic crystals for emission control", "venue": "Journal of Physics: Conference Series", "year": 2019 }, { "abstract": "An ensemble of emitters can behave very differently from its individual constituents when they interact coherently via a common light field. After excitation of such an ensemble, collective coupling can give rise to a many body quantum phenomenon that results in short, intense bursts of light so called superfluorescence1. Because this phenomenon requires a fine balance of interactions between the emitters and their decoupling from the environment, together with close identity of the individual emitters, superfluorescence has thus far been observed only in a limited number of systems, such as certain atomic and molecular gases and a few solid state systems2 7. The generation of superfluorescent light in colloidal nanocrystals (which are bright photonic sources practically suited for optoelectronics8,9) has been precluded by inhomogeneous emission broadening, low oscillator strength, and fast exciton dephasing. Here we show that caesium lead halide (CsPbX3, X Cl, Br) perovskite nanocrystals10 13 that are self organized into highly ordered three dimensional superlattices exhibit key signatures of superfluorescence. These are dynamically red shifted emission with more than 20 fold accelerated radiative decay, extension of the first order coherence time by more than a factor of four, photon bunching, and delayed emission pulses with Burnham Chiao ringing behaviour14 at high excitation density. These mesoscopically extended coherent states could be used to boost the performance of opto electronic devices15 and enable entangled multi photon quantum light sources16,17.Cooperative quantum effects in superlattices of quantum dots made of caesium lead halide perovskite give rise to superfluorescence, with the individual emitters interacting coherently to give intense bursts of light.", "author_names": [ "Gabriele Raino", "Michael A Becker", "Maryna I Bodnarchuk", "Rainer F Mahrt", "Maksym V Kovalenko", "Thilo Stoferle" ], "corpus_id": 53213886, "doc_id": "53213886", "n_citations": 180, "n_key_citations": 0, "score": 0, "title": "Superfluorescence from lead halide perovskite quantum dot superlattices", "venue": "Nature", "year": 2018 }, { "abstract": "Silicon nitride (Si3N4) waveguide platforms [1,2] are interesting candidates for optical interconnects and sensing applications [3] thanks to high quality passive components, transparency for NIR and visible wavelengths and their compatibility with CMOS process technology. Unfortunately, no native light sources are available for Si3N4 platforms and the integration of active materials, i.e. III V compounds, is costly and often not CMOS compatible. Metal halide perovskites are a class of solution processed semiconductors suitable for lasing [4] Thanks to low cost deposition by spin coating and low temperature processing (below 100degC) they are a great option for industry relevant on chip light sources. In this work we apply the MAPbI3 perovskite onto Si3N4 integrated chips to obtain, to our knowledge, the first integrated perovskite laser.", "author_names": [ "Piotr J Cegielski", "Stefanie Neutzner", "C Porschatis", "Holger Lerch", "Jens Bolten", "Stephan Suckow", "Ajay Ram Srimath Kandada", "Bartos Chmielak", "Annamaria Petrozza", "T Wahlbrink", "Anna Lena Giesecke" ], "corpus_id": 6578968, "doc_id": "6578968", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Perovskite laser integrated on a conventional Si3N4 photonic platform", "venue": "2017 Conference on Lasers and Electro Optics Europe European Quantum Electronics Conference (CLEO/Europe EQEC)", "year": 2017 }, { "abstract": "Perovskite solar cells (PSCs) have reached certified efficiencies of up to 23.7% but suffered from frailness and instability when exposed to ambient atmosphere. Zinc oxide (ZnO) when used as electron transport layer (ETL) on PSCs, gives rise to excellent electronic, optic, and photonic properties, yet the Lewis basic nature of ZnO surface leads to deprotonation of the perovskite layer, resulting in serious degradation of PSCs using ZnO as ETL. Here, we report a simple but effective strategy to convert ZnO surface into ZnS at the ZnO/perovskite interface by sulfidation. The sulfide on ZnO ZnS surface binds strongly with Pb2+ and creates a novel pathway of electron transport to accelerate electron transfer and reduce interfacial charge recombination, yielding a champion efficiency of 20.7% with improved stability and no appreciable hysteresis. The model devices modified with sulfide maintained 88% of their initial performance for 1000 h under storage condition and 87% for 500 h under UV radiation. ZnS is demonstrated to act as both a cascade ETL and a passivating layer for enhancing the performance of PSCs.", "author_names": [ "Ruihao Chen", "Jing Cao", "Yuan Duan", "Yong Hui", "Tracy T Chuong", "Daohui Ou", "Faming Han", "Fangwen Cheng", "Xiaofeng Huang", "Binghui Wu", "Nanfeng Zheng" ], "corpus_id": 54471672, "doc_id": "54471672", "n_citations": 83, "n_key_citations": 1, "score": 0, "title": "High Efficiency, Hysteresis Less, UV Stable Perovskite Solar Cells with Cascade ZnO ZnS Electron Transport Layer.", "venue": "Journal of the American Chemical Society", "year": 2019 } ]
Bubble Image Velocimetry with an Acoustic Camera
[ { "abstract": "BACKGROUND: BIV is a subset of particle image velocimetry (PIV) a common laboratory experimental technique used to measure flow velocity. In traditional particle image velocimetry, the flow of interest is seeded with tracer particles that reflect light and are assumed to faithfully follow the motion of the fluid, which is a valid assumption with sufficiently small particles (Adrian and Westerweel 2011) In BIV, bubbles are used in place of tracer particles (Ryu et al. 2005) In either case, the motion of the tracer particles/bubbles is observed generally with a charge coupled device or complementary metal oxide semiconductor digital camera for modern systems and used to quantify the flow velocity. The flow velocity is measured by sub dividing the camera images into windows (e.g. 16 x 16 pixels) then, cross correlation is used to determine the aggregate displacement of all the particles in each window between successive images (Raffel et al. 2007) However, traditional PIV and BIV measurement techniques with an optical camera are difficult to deploy in the field because they are equipment intensive, require stationary, well calibrated images, and can only be performed in a reasonably transparent fluid (such that the optical camera can see the tracer particles/bubbles) Obviously these requirements quickly become restrictive in field deployments, particularly in highly turbid environments near dredging operations.", "author_names": [ "David L Young", "Brian C McFall", "Duncan Burnette Bryant" ], "corpus_id": 195550489, "doc_id": "195550489", "n_citations": 1, "n_key_citations": 0, "score": 2, "title": "Bubble image velocimetry with an acoustic camera", "venue": "", "year": 2019 }, { "abstract": "BACKGROUND: BIV is a subset of particle image velocimetry (PIV) a common laboratory experimental technique used to measure flow velocity. In traditional particle image velocimetry, the flow of interest is seeded with tracer particles that reflect light and are assumed to faithfully follow the motion of the fluid, which is a valid assumption with sufficiently small particles (Adrian and Westerweel 2011) In BIV, bubbles are used in place of tracer particles (Ryu et al. 2005) In either case, the motion of the tracer particles/bubbles is observed generally with a charge coupled device or complementary metal oxide semiconductor digital camera for modern systems and used to quantify the flow velocity. The flow velocity is measured by sub dividing the camera images into windows (e.g. 16 x 16 pixels) then, cross correlation is used to determine the aggregate displacement of all the particles in each window between successive images (Raffel et al. 2007) However, traditional PIV and BIV measurement techniques with an optical camera are difficult to deploy in the field because they are equipment intensive, require stationary, well calibrated images, and can only be performed in a reasonably transparent fluid (such that the optical camera can see the tracer particles/bubbles) Obviously these requirements quickly become restrictive in field deployments, particularly in highly turbid environments near dredging operations.", "author_names": [ "David L Young", "Brian C McFall", "Duncan Burnette Bryant" ], "corpus_id": 209799372, "doc_id": "209799372", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "ERDC/TN DOER I7 \"Bubble Image Velocimetry with an Acoustic Camera\"", "venue": "", "year": 2019 }, { "abstract": "", "author_names": [ "David L Young", "Brian C McFall", "Duncan Burnette Bryant" ], "corpus_id": 126352282, "doc_id": "126352282", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Bubble image velocimetry with a field deployable acoustic camera", "venue": "", "year": 2018 }, { "abstract": "A drop impacting on a liquid surface may entrain a bubble resulting in sounds from the bubble oscillation in addition to that of the initial drop impact. This subject has received considerable interest with respect to the underwater sound produced by rain. The previous optical and acoustical studies have extensively examined the role of drop size and impact velocity as well entrainment formation mechanisms. However, the role of surfactants on the liquid surface has received less attention especially with respect to sound production. One previous study [1] of two different surfactants (Kodak Photoflo and a sulfo detergent) reports that these suppress entrainment resulting in diminished or negligible bubble noise. However, we have found bubble entrainment and acoustic emissions associated with the addition of a heptane layer on the water surface. Using a synchronized hydrophone and a high speed camera, acoustical and optical data of the bubble drop dynamics were obtained. Particle image velocimetry (PIV) was also utilized to measure the surface velocity produced by the drop. These results show a significant difference in the drop rebound and subsequent fluid column dynamics, which results in a dual acoustic emission for the surfactant case.Copyright (c) 2010 by ASME", "author_names": [ "Christopher N Layman", "John Stefan Allen", "In Mei Sou" ], "corpus_id": 102296949, "doc_id": "102296949", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Influence of Surfactants on Bubble Entrainment", "venue": "", "year": 2010 }, { "abstract": "Theory of cross correlation analysis of PIV images. Decay of rotating turbulence: Some particle tracking experiments. Measurement of product concentration of two parallel reactive jets using digital image processing. Image analysis of oil film interferometry a method of measuring wall shear stress distributions. Recent advances in LSV, PIV and PTV. Development of particle image velocimetry: A new computation method with directional resolution. Algorithms for automatic measurements of size and velocity of spray droplets from holography reconstructions. Characterization of Savonius rotor wake using image analysis processing techniques. An application of image processing methods to determine the critical shear stress in sewer systems. A three dimensional particle image velocimetry system and its application to the measurement of acoustic streaming. A camera for measuring density, size and velocity of rising air bubbles and water velocity in a bubble plume. The application of PIV to turbulent two phase flow. A critical analysis of the particle image velocimetry technique as applied to waves. A colored method for PIV technique. Digital PIV applied to flows around artificial heart valves: Analysis by autocorrelation.", "author_names": [ "F T M Nieuwstadt" ], "corpus_id": 117183214, "doc_id": "117183214", "n_citations": 30, "n_key_citations": 1, "score": 0, "title": "Flow visualization and image analysis", "venue": "", "year": 1993 }, { "abstract": "The bubble image velocimetry (BIV) technical was implemented in a large wave basin for the first time to study its feasibility of measuring velocities in a greenwater flow. The greenwater flow was generated by the impingement of a plunging breaking wave onto a horizontal model deck formed by a square plate. A LED panel was used as the deck and the light source of the BIV system. A high speed camera was used to record images for BIV velocity determination. Measurements taken in the large model basin were used to compare with measurements taken in a small wave tank in a laboratory for examining the scale effect.", "author_names": [ "Kuang-An Chang", "Youn Kyung Song", "Kusalika Ariyarathne", "Richard Mercier" ], "corpus_id": 227084018, "doc_id": "227084018", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Greenwater Velocity Measurements In a Large Scale Wave Basin Using Bubble Image Velocimetry", "venue": "", "year": 2012 }, { "abstract": "Abstract The ultrasonic assisted water confined laser micromachining is a novel micromachining method. This paper reports the experimental studies of ultrasonic power and water layer thickness on the laser (1064 nm nanosecond pulse laser) micromachining of silicon. Besides, this reports a systematic discussion on the influence of the acoustic streaming and bubbles (induced by laser) dynamic change on the machining process. The acoustic streaming and flow pattern under different ultrasonic power application and different water layer thickness using Particle Image Velocimetry (PIV) A finite element (FE) heat transfer model was employed to gain a better understanding of the effect of the acoustic streaming velocity on the temperature field change in laser processing. The bubbles (induced by laser) dynamic behavior is observed by the high speed camera. The results showed that the ultrasonic assisted laser ablation can yield much higher the material removal rate than laser cutting in water without ultrasonic assisted. Besides, the increase in the ultrasonic power helps to improve the etching efficiency but is not apparent. When the water layer thickness is 1 mm, the cutting effect is significantly different from the laser ablation in the other three water layers. Through the PIV images and simulate results, it has been found that the influence of acoustic streaming on heat transfer in laser processing is small. Through high speed camera imaging observations, the dynamic change of bubbles is an essential mechanism for the enhanced material removal rate and affect the machining performance in this study. This study helps understand the mechanism of ultrasonic assisted water confined laser micromachining better and promoting this technique potential application in the micromachining of hard brittle materials.", "author_names": [ "Jia Zhou", "Rongwei Xu", "Hui Jiao", "Qing-yuan Liu", "Yuhong Long" ], "corpus_id": 219007409, "doc_id": "219007409", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Study on the mechanism of ultrasonic assisted water confined laser micromachining of silicon", "venue": "", "year": 2020 }, { "abstract": "Abstract A plunging breaking wave of 1 m height was generated in a very large wave tank of 5 m in width, 5 m in depth, and 300 m in length filled with freshwater. The surface velocities in the highly aerated region of the breaking wave were measured using bubble image velocimetry (BIV) while the void fraction profiles were measured using fiber optic reflectometers (FOR) The internal velocities below the aerated region were also measured using an array of acoustic Doppler velocimeters (ADV) A wavelet based technique was used to detect vortical structures at the free surface and estimate their length scales. The measured surface velocity fields were decomposed into wave induced and turbulence induced components to investigate the temporal and spatial evolution of mean kinetic energy and turbulent kinetic energy. It was found that turbulence is advected and diffused mainly following the phase speed of the breaking wave, rather than from the wave group velocity during the first splash up process. The internal velocity measurements below the aerated regions show that turbulent kinetic energy decreases exponentially as the depth increases. Since scale effects under breaking waves with turbulence and air entrainment are less understood, results in flow kinematics, turbulence, and void fraction in the present study were compared with that in Lim et al. (2015) which investigated small scale plunging breaking waves with a 0.2 m wave height. It was found that flow kinematics and some dynamic properties such as void fraction and turbulent kinetic energy can be well represented between different physical scales if the traditional Froude scaling law is applied. Other dynamic properties, including bubble number and size distributions, seem to be significantly affected by the physical scales.", "author_names": [ "Byoungjoon Na", "Kuang-An Chang", "Zhi-Cheng Huang", "Wen Yang Hsu", "Wei-Liang Chuang", "Yang-Yih Chen" ], "corpus_id": 135024926, "doc_id": "135024926", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Large scale laboratory observation of flow properties in plunging breaking waves", "venue": "", "year": 2018 }, { "abstract": "A number of acoustic and fluid dynamic phenomena appear in ultrasonic cleaning baths and contribute to physical cleaning of immersed surfaces. Propagation and repeated reflection of ultrasound within cleaning baths build standing wave like acoustic fields; when an ultrasound intensity gradient appears in the acoustic fields, it can in principle induce steady streaming flow. When the ultrasound intensity is sufficiently large, cavitation occurs and oscillating cavitation bubbles are either trapped in the acoustic fields or advected in the flow. These phenomena are believed to produce mechanical action to remove contaminant particles attached at material surfaces. Recent studies suggest that the mechanical action of cavitation bubbles is the dominant factor of particle removal in ultrasonic cleaning, but the bubble collapse resulting from high intensity ultrasound may be violent enough to give rise to surface erosion. In this paper, we aim to carefully examine the role of cavitation bubbles from ultrasonic cleaning tests with varying dissolved gas concentration in water. In our cleaning tests using 28 kHz ultrasound, oxygen supersaturated water is produced by oxygen microbubble aeration and used as a cleaning solution, and glass slides spin coated with silica particles of micron/submicron sizes are used to define cleaning efficiency. High speed camera recordings and Particle Image Velocimetry analysis with a pressure oscillation amplitude of 1.4 atm at the pressure antinode show that the population of cavitation bubbles increases and streaming flow inside the bath is promoted, as the dissolved oxygen supersaturation increases. The particle removal is found to be achieved mainly by the action of cavitation bubbles, but there exists optimal gas supersaturation to maximize the removal efficiency. Our finding suggests that low intensity ultrasound irradiation under the optimal gas supersaturation in cleaning solutions allows for having mild bubble dynamics without violent collapse and thus cleaning surfaces without cavitation erosion. Finally, observations of individual bubble dynamics and the resulting particle removal are reported to further support the role of cavitation bubbles as cleaning agents.", "author_names": [ "Tatsuya Yamashita", "Keita Ando" ], "corpus_id": 58566015, "doc_id": "58566015", "n_citations": 25, "n_key_citations": 0, "score": 0, "title": "Low intensity ultrasound induced cavitation and streaming in oxygen supersaturated water: Role of cavitation bubbles as physical cleaning agents.", "venue": "Ultrasonics sonochemistry", "year": 2019 }, { "abstract": "Abstract The present study employed the image based bubble image velocimetry (BIV) technique to investigate the flow kinematics of a plunging breaking wave impinging on a geometry simplified, unrestrained tension leg platform (TLP) A high speed camera was used to record images for the BIV velocity determination for both fluid and structure velocities. The plunging breaker was generated using a wave focusing method, and repeated measurements were acquired to calculate the mean flow and turbulence intensity using ensemble averaging. BIV measurements were performed on two perpendicular planes: side view and top view. The flow measurements were compared with those of a similar experiment on a fixed structure by Ryu et al. (Exp Fluids 43(4):555 567, 2007a) The maximum velocity occurred in the run up stage with a magnitude reaching 2.8C with C being the phase speed of the breaking wave. The dominant velocities for three distinct phases impingement, run up, and overtopping are very close to those found on the fixed structure. Turbulence intensity was also examined, and the ratio among the three components was quantified. Ryu et al. (Appl Ocean Res 29(3):128 136, 2007b) reported that Ritter's dam break flow solution agrees surprisingly well with the measured green water velocity on the fixed structure to a certain degree. The present study followed the same approach and confirmed that Ritter's solution is also in excellent agreement with the green water velocity on the unrestrained TLP model. Based on the self similar behavior, the prediction equation proposed by Ryu et al. (2007a) was used to model the green water velocity distribution. The results show that the prediction equation is applicable to not only a fixed structure, but also the unrestrained TLP for green water velocity caused by extreme waves.", "author_names": [ "Wei-Liang Chuang", "Kuang-An Chang", "Richard Mercier" ], "corpus_id": 118271696, "doc_id": "118271696", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Green water velocity due to breaking wave impingement on a tension leg platform", "venue": "", "year": 2015 } ]
n-type colloidal semiconductor nanocrystals Nature， 2000，407,981-983
[ { "abstract": "Colloidal semiconductor nanocrystals combine the physical and chemical properties of molecules with the optoelectronic properties of semiconductors. Their colour is highly controllable, a direct consequence of quantum confinement on the electronic states. Such nanocrystals are a form of 'artificial atoms' (ref. 4) that may find applications in optoelectronic systems such as light emitting diodes and photovoltaic cells, or as components of future nanoelectronic devices. The ability to control the electron occupation (especially in n type or p type nanocrystals) is important for tailoring the electrical and optical properties, and should lead to a wider range of practical devices. But conventional doping by introducing impurity atoms has been unsuccessful so far: impurities tend to be expelled from the small crystalline cores (as observed for magnetic impurities) and thermal ionization of the impurities (which provides free carriers) is hindered by strong confinement. Here we report the fabrication of n type nanocrystals using an electron transfer approach commonly employed in the field of conducting organic polymers. We find that semiconductor nanocrystals prepared as colloids can be made n type, with electrons in quantum confined states.", "author_names": [ "Moonsub Shim", "Philippe Guyot-Sionnest" ], "corpus_id": 4334585, "doc_id": "4334585", "n_citations": 340, "n_key_citations": 1, "score": 1, "title": "n type colloidal semiconductor nanocrystals", "venue": "Nature", "year": 2000 }, { "abstract": "SSNanoparticles of metallic copper (Cu 0 and copper I oxide (Cu2O) have been prepared through a new nonhydrolytic precursor approach by applying template mineralization of self assembled anisotropic double chained cationic lipids (2C12 18NMe2OH) in the presence of pyruvylated xanthan (0.0001% w/w) in the presence of a suitable redox system. The controlled formation of defined inorganic cationic lipid composites by using the self assembled vesicles (spherical, rod like or tubular) as templates lead to the formation of defined nanocrystals of Cu 0 or Cu2O in astonishing shape dependent manner as shown by small angle X ray scattering, transmission electron microscopy (TEM) and light scattering methods. Spherical, rodshaped nanocrystals could be obtained, particularly for Cu2O which is very light sensitive (at~580 nm) and can act as a p type semiconductor. The formed and isolated nanoparticles have average sizes of 6.0 12.0 nm in diameter for Cu2O and of 7.0 12.0 nm in diameter for the metallic Cu 0 nanocrystals as determined from small angle X ray scattering, transmission electron microscopy and powder diffraction, respectively. The formation of nanoclusters of zerovalent copper of sizes between 7 and 12 nm show a surface plasma bond at 561 566 nm. The reduction of the copper salts to colloidal copper in the presence of the glycolipids A B can be enhanced through addition of less than 10 molecules of didocyldimethylammonium hydroxide per biosurfactant micelle in the presence of l0 mM (R* R* 1,4 dimercapto 2,3 dibutandiol. The addition of the cationic surfactant induced a strong increase in the size and in the yield as observed by TEM, small angle X ray scattering and light scattering measurements. Due to the low CMC of the double chained cationic lipids including their very low surface tension which is significantly affected by the nature of the counterions enables one to produce large quantities of Cu nano clusters having different shapes. The nature of the counterions are also found to be crucial in the synthesis of zero valent copper nano clusters.", "author_names": [ "H Henrich Paradies", "Michael Thies", "Ulrike Hinze" ], "corpus_id": 55345268, "doc_id": "55345268", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "TEMPLATE MINERALIZATION OF ORDERED NANOMATERIALS OF METALLIC COPPER AND COPPER I OXIDES IN THE PRESENCE OF DOUBLE CHAINED CATIONIC LIPIDS (Ill)", "venue": "", "year": 2000 }, { "abstract": "The Redox Potentials of n Type Colloidal Semiconductor Nanocrystals", "author_names": [ "Gerard Michael Carroll" ], "corpus_id": 99213996, "doc_id": "99213996", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The Redox Potentials of n type Colloidal Semiconductor Nanocrystals", "venue": "", "year": 2016 }, { "abstract": "In the present work, we demonstrate crystallographically textured n type Bi2Te3 xSe x nanomaterials with exceptional thermoelectric figures of merit produced by consolidating disk shaped Bi2Te3 xSe x colloidal nanocrystals (NCs) Crystallographic texture was achieved by hot pressing the asymmetric NCs in the presence of an excess of tellurium. During the hot press, tellurium acted both as lubricant to facilitate the rotation of NCs lying close to normal to the pressure axis and as solvent to dissolve the NCs approximately aligned with the pressing direction, which afterward recrystallize with a preferential orientation. NC based Bi2Te3 xSe x nanomaterials showed very high electrical conductivities associated with large charge carrier concentrations, n. We hypothesize that such large n resulted from the presence of an excess of tellurium during processing, which introduced a high density of donor TeBi antisites. Additionally, the presence in between grains of traces of elemental Te, a narrow band gap semiconductor with a work function well below Bi2Te3 xSe x, might further contribute to increase n through spillover of electrons, while at the same time blocking phonon propagation and hole transport through the nanomaterial. NC based Bi2Te3 xSe x nanomaterials were characterized by very low thermal conductivities in the pressing direction, which resulted in ZT values up to 1.31 at 438 K in this direction. This corresponds to a ca. 40% ZT enhancement from commercial ingots. Additionally, high ZT values were extended over wider temperature ranges due to reduced bipolar contribution to the Seebeck coefficient and the thermal conductivity. Average ZT values up to 1.15 over a wide temperature range, 320 to 500 K, were measured, which corresponds to a ca. 50% increase over commercial materials in the same temperature range. Contrary to most previous works, highest ZT values were obtained in the pressing direction, corresponding to the c crystallographic axis, due to the predominance of the thermal conductivity reduction over the electrical conductivity difference when comparing the two crystal directions.", "author_names": [ "Yupu Liu", "Yuanwei Zhang", "Khak Ho Lim", "Maria Ibanez", "Silvia Ortega", "Mengyao Li", "Jeremy David", "Sara Marti-Sanchez", "Ka Ming Ng", "Jordi Arbiol", "Maksym V Kovalenko", "Doris Cadavid", "Andreu Cabot" ], "corpus_id": 206721166, "doc_id": "206721166", "n_citations": 49, "n_key_citations": 1, "score": 0, "title": "High Thermoelectric Performance in Crystallographically Textured n Type Bi2Te3 xSe x Produced from Asymmetric Colloidal Nanocrystals.", "venue": "ACS nano", "year": 2018 }, { "abstract": "", "author_names": [ "Robertson Ansah Bill" ], "corpus_id": 137974811, "doc_id": "137974811", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Electron Transfer Produces n Type Colloidal Semiconductor Nanocrystals", "venue": "", "year": 2001 }, { "abstract": "Assemblies of colloidal semiconductor nanocrystals (NCs) in the form of thin solid films leverage the size dependent quantum confinement properties and the wet chemical methods, vital for the development of the emerging solution processable electronics, photonics and optoelectronics technologies. The ability to control the charge carrier transport in the colloidal NC assemblies is fundamental for altering their electronic and optical properties for the desired applications. Here we demonstrate a strategy to render the solids of narrow bandgap NC assemblies exclusively electron transporting by creating type II heterojunction via shelling. Electronic transport of molecularly cross linked PbTe@PbS core@shell NC assemblies is measured using both conventional solid gate transistor and electric double layer transistor, as well as compared with those of core only PbTe NCs. In contrast to the ambipolar characteristics demonstrated by many narrow bandgap NCs, the core@shell NCs exhibit exclusive n type transport; i.e. drastically suppressed contribution of holes to the overall transport. The PbS shell that forms type II heterojunction assists the selective carrier transport by heavy doping of electrons into the PbTe core conduction level, and simultaneously strongly localize the holes within the NC core valence level. This strongly enhanced n type transport makes these core@shell NCs suitable for applications where ambipolar characteristics should be actively suppressed; in particular, for thermoelectric and electron transporting layer in photovoltaic devices.", "author_names": [ "Retno Miranti", "Daiki Shin", "Ricky Dwi Septianto", "Maria Ibanez", "Maksym V Kovalenko", "Nobuhiro Matsushita", "Yoshihiro Iwasa", "Satria Zulkarnaen Bisri" ], "corpus_id": 211213682, "doc_id": "211213682", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Exclusive Electron Transport in Core@Shell PbTe@PbS Colloidal Semiconductor Nanocrystal Assemblies.", "venue": "ACS nano", "year": 2020 }, { "abstract": "Precise control over the shape and elemental composition of colloidal nanocrystals (NCs) is challenging, especially for anisotropic growth. While the most studied nanocrystal syntheses involve homogenous nucleation and growth, the solution based approach involving heterogenous growth from ion conductive seeds has proved to be very efficient yet less explored. The static nature and superionic conductivity of the seeds enable rapid cation transport for catalysis of defect free, phase pure NC growth. This review aims to explain the significance of ion conductive solid seed based synthesis from a mechanistic point of view to produce 1D and quasi 1D NCs for applications such as photocatalysis, photovoltaics, and photodetectors. We highlight the significant synthetic information reported for heterostructure and alloyed metal chalcogenide NCs synthesized via solution solid solid and diffusion controlled growth based on several kinetic and thermodynamic growth parameters. We also provide a perspective on the areas that hold promise and are in need of further development.", "author_names": [ "Nilotpal Kapuria", "Uma V Ghorpade", "Maria Zubair", "Mohini Mishra", "Shalini Singh", "Kevin M Ryan" ], "corpus_id": 225362944, "doc_id": "225362944", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Metal chalcogenide semiconductor nanocrystals synthesized from ion conducting seeds and their applications", "venue": "", "year": 2020 }, { "abstract": "Optically bright colloidal semiconductor nanocrystals (CSNCs) are important nanomaterials because of their potential applications such as cellular imaging and solid state lighting. The optoelectronic properties of CSNCs are strongly controlled by the chemical nature of the surface passivating ligands that are introduced during their synthesis. However, the existing LaMer growth model does not provide a clear understanding of the stage when ligands become attached onto the CSNC surface. Herein, apart from the three stage formation mechanism of CSNCs (supersaturation, nucleation, and growth) an entirely new stage solely involving surface ligand attachment onto fully grown CSNCs is now reported that controls their photoluminescence properties. Furthermore, we also demonstrate a fundamentally new surface modification approach using partially passivated CSNCs to introduce a variety of functional groups (azide, alkene, and siloxane) including photoisomerizable molecular machines (e.g. azobenzene) without th.", "author_names": [ "Meghan B Teunis", "Thakshila Liyanage", "Sukanta Dolai", "Barry B Muhoberac", "Rajesh Sardar", "Mangilal Agarwal" ], "corpus_id": 55067093, "doc_id": "55067093", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Unraveling the Mechanism Underlying Surface Ligand Passivation of Colloidal Semiconductor Nanocrystals: A Route for Preparing Advanced Hybrid Nanomaterials", "venue": "", "year": 2017 }, { "abstract": "Heterovalent doping in colloidal semiconductor nanocrystals (CSNCs) with provisions of extra electrons (n type doping) or extra holes (p type doping) could enhance their performance of optical and electronical properties. In view of the challenges imposed by the intrinsic self purification, self quenching, and self compensation effects of CSNCs, we outline the progress on heterovalent doping in CSNCs, with particular focus on the cation exchange enabled tuning of dopant luminescence and electronic impurities. Thus, the well defined substitutional or interstitial heterovalent doping in a deep position of an isolated nanocrystal has been fulfilled. We also envision that new coordination ligand initiated cation exchange would bring about more choices of heterovalent dopants. With the aid of high resolution characterization methods, the accurate atom specific dopant location and distribution could be confirmed clearly. Finally, new applications, some of the remaining unanswered questions, and future directions of this field are presented.", "author_names": [ "Jiatao Zhang", "Qiumei Di", "Jia Liu", "Bing Bai", "Jian Liu", "Meng Xue Xu", "Jiajia Liu" ], "corpus_id": 46771862, "doc_id": "46771862", "n_citations": 38, "n_key_citations": 0, "score": 0, "title": "Heterovalent Doping in Colloidal Semiconductor Nanocrystals: Cation Exchange Enabled New Accesses to Tuning Dopant Luminescence and Electronic Impurities.", "venue": "The journal of physical chemistry letters", "year": 2017 }, { "abstract": "Colloidal semiconductor quantum wells have emerged as a promising material platform for use in solution processable lasers. However, applications relying on their optical gain suffer from nonradiative Auger decay due to multi excitonic nature of light amplification in II VI semiconductor nanocrystals. Here, we show sub single exciton level of optical gain threshold in specially engineered CdSe/CdS@CdZnS core/crown@gradient alloyed shell quantum wells. This sub single exciton ensemble averaged gain threshold of N g 0.84 (per particle) resulting from impeded Auger recombination, along with a large absorption cross section of quantum wells, enables us to observe the amplified spontaneous emission starting at an ultralow pump fluence of 800 nJ cm 2 at least three folds better than previously reported values among all colloidal nanocrystals. Finally, using these gradient shelled quantum wells, we demonstrate a vertical cavity surface emitting laser operating at a low lasing threshold of 7.5 mJ cm 2 These results represent a significant step towards the realization of solution processable electrically driven colloidal lasers. Colloidal quantum wells are highly promising for applications of solution processed lasers, but their performance is limited by multi excitonic nature of the materials. Here, the authors demonstrate optical gain in graded alloy core/shell CdSe/CdS@CdZnS quantum wells at less than one exciton per particle resulting in ultralow thresholds.", "author_names": [ "Nima Taghipour", "Savas Delikanli", "Sushant Shendre", "Mustafa Sak", "Mingjie Li", "Furkan Isik", "Ibrahim Tanriover", "Burak Guzelturk", "Tze Chien Sum", "Hilmi Volkan Demir" ], "corpus_id": 189928351, "doc_id": "189928351", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Sub single exciton optical gain threshold in colloidal semiconductor quantum wells with gradient alloy shelling", "venue": "Nature Communications", "year": 2020 } ]
current ripple‘s influence on EMI filter
[ { "abstract": "With new semiconductor technologies of outstanding performance each day more accessible, higher power density converters are being developed and introduced in the market, taking advantage of the potential increase on switching frequency offered by such devices without efficiency decrease. Attempting a further inductor size decrease, its value can be reduced, consequently increasing the current ripple up to trade off between size and magnetic losses. However, the operation with higher switching frequency yields unusual EMI issues, as the higher magnitude harmonics (1st, 2nd, etc) of the generated noise to be attenuated are located close to or within the frequency range limited by current EMC standards. The current ripple also influences the harmonic content, increasing the noise amplitude. Therefore, based on a grid connected full bridge inverter, this paper presents an analysis towards the influences of the current ripple and switching frequency on the overall losses, minimization possibility and EMI filter design.", "author_names": [ "Andressa C Schittler", "Thiemo Kleeb", "Mehmet Kazanbas", "Samuel Vasconcelos Araujo", "Peter Zacharias" ], "corpus_id": 114794818, "doc_id": "114794818", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Considerations on the influence of the current ripple and switching frequency towards the differential mode EMI filter", "venue": "", "year": 2016 }, { "abstract": "Interleaved Power Factor Correction (PFC) has become a most popular topology from efficiency and power density point of view over single switch boost PFC. The dependency of the Differential Model (DM) Electromagnetic Interference (EMI) noise magnitude on input current ripple leads to investigate the influence of the interleaved technique on EMI noise. Hence, this paper provides a comprehensive investigation for the design of DM EMI filter a single phase interleaved PFC targeting to minimize component size. It is shown how different operation modes (continuous and discontinuous conduction mode) and switching frequency may influence the required filter attenuation and, consequently, the EMI filter size. Furthermore, the impact of the number of interleaved stages and optimal phase shifting on the required filter attenuation is analyzed. Finally, the influence of optimal phase shifting achieve an overall minimum EMI filter corner frequency is discussed. Experimental results from a 2 kW interleaved single phase boost PFC converter validate the effectiveness of the proposed optimal phase shifting method.", "author_names": [ "Naser Nourani Esfetanaj", "Yamen Saad", "Omar Ahmed Sakaria", "Huai Wang", "Pooya Davari" ], "corpus_id": 222221210, "doc_id": "222221210", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Differential Model EMI Filter Analysis for Interleaved Boost PFC Converters Considering Optimal Phase Shifting", "venue": "2020 22nd European Conference on Power Electronics and Applications (EPE'20 ECCE Europe)", "year": 2020 }, { "abstract": "A low source current ripple fourth order buck converter (LSCRBUC) is proposed in this paper. Like buck converter with input filter, it has four L C elements but structurally different from it. Use of input L C filter is essential in the conventional buck converters to meet the ripple specifications but it is at the cost stability issues. To minimize the stability issues in these topologies an additional damping network is necessary. The proposed converter is free from damping network and ensures tradeoff ripples with minimum stability issues related to input filter. The stability issues are analyzed through the combination of participation factors and eigenvalue approach. Also, the influence various states associated to the L C parameters on the dominant modes/instability issues are brought out. Case studies are presented for the low source current ripple buck converter and compared with the conventional fourth order buck converter. Analytical findings are validated with stability indicating analytical and measurement results.", "author_names": [ "Mummadi Veerachary", "" ], "corpus_id": 232373964, "doc_id": "232373964", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design and Stability Analysis of Low Source Current Ripple Buck Converters", "venue": "2020 IEEE International Conference on Power Electronics, Drives and Energy Systems (PEDES)", "year": 2020 }, { "abstract": "In battery fed pulse width modulated inverters, a high battery current ripple can cause electromagnetic interference problems or increased losses. A proper battery, cable and input filter design requires an accurate prediction of the battery current ripple. Hence, this paper proposes a fast simulation model for predicting this current ripple in battery fed pulse width modulated inverters. Based on this simulation model, an extensive parameter study is performed investigating the influence of different parameters on the battery current ripple. This study is presented in a normalized form. Thus, the results can be easily applied to any battery fed pulse width modulated inverter.", "author_names": [ "Panagiotis Mantzanas", "Daniel Kuebrich", "Thomas Duerbaum" ], "corpus_id": 227279634, "doc_id": "227279634", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Fast and Accurate Calculation Method for Predicting the Battery Current Ripple in Battery fed PWM Inverter Systems", "venue": "2020 IEEE 21st Workshop on Control and Modeling for Power Electronics (COMPEL)", "year": 2020 }, { "abstract": "Improvement of surge immunity due to transformer isolation in an active EMI filter (AEF) is investigated. The surge influence on active circuit parts is analyzed by experiments. Maximum peak voltage and pulse duration of the surge transient voltages transferred to active circuit parts of a current sense current compensation (CSCC) AEF are measured in the cases with direct capacitive coupling and transformer isolated coupling, respectively. The surge immunity of the designed transformer isolated CSCC AEF is validated under numerous 4kV surge tests and VNA measurement.", "author_names": [ "Sangyeong Jeong", "Jingook Kim" ], "corpus_id": 201847839, "doc_id": "201847839", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Improvement of Surge Immunity by Using Transformer isolation in an Active EMI Filter", "venue": "2019 IEEE International Symposium on Electromagnetic Compatibility, Signal Power Integrity (EMC+SIPI)", "year": 2019 }, { "abstract": "This paper gives an analysis of mutual inductive couplings of the CM EMI filter in motor drive. First, the high frequency model of L C EMI filter is proposed, then, equivalent decoupling circuits are established based on the method of transferring controlled voltage source. It is concluded by calculation that some mutual inductive couplings have an effect on the transfer gain of EMI filter in the whole frequency spectrum of EMI current. While some mutual inductive couplings influence the transfer gain only at high frequency range. Finally, in order to drop the EMI current below the standard, the combination of an optimized EMI filter and an advanced method are adopted.", "author_names": [ "Zhihao Fang", "Dong Jiang", "Zaidong Hu" ], "corpus_id": 201065504, "doc_id": "201065504", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Analysis and Suppression of Mutual Inductive Couplings of the CM EMI Filter in Motor Drive", "venue": "2019 10th International Conference on Power Electronics and ECCE Asia (ICPE 2019 ECCE Asia)", "year": 2019 }, { "abstract": "Wide range of parameters selection and multiple iterations are still needed in most of the existing design procedures of LCL filter. Moreover, the current ripple cannot be accurately decided, and the damping resistance, which can affect the current ripple, control stability and filter losses, is hard to be optimized. To solve these problems, this paper presents more accurate calculations of maximum peak to peak current ripple on both sides of the filter under different power levels, wire connections and modulation strategies. The damping resistance is designed in a new manner to achieve an optimized damping ratio. Finally, grid side inductance is calculated more accurately by considering the influence of damping resistance and the changing rate of current attenuation. The primary goal is to provide a more accurate, general and efficient design for LCL filter with little iterations, and to ensure that the current ripples can be accurately estimated and be set as new design target.", "author_names": [ "Weiyu Tang", "Yubo Song", "Ran Cheng", "Ke Ma" ], "corpus_id": 54448618, "doc_id": "54448618", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Current Ripple Oriented Design of LCL Filter for Three Phase Voltage Source Converter with Different Wire Connections and Modulations", "venue": "2018 IEEE Energy Conversion Congress and Exposition (ECCE)", "year": 2018 }, { "abstract": "An accurate iron loss estimation is necessary before manufacturing the filter inductors of the three phase grid connected converters. Besides the loss characteristics of the magnetic core, obtaining an accurate current flowing through the inductor is also very important in the iron loss estimation. In three phase grid connected converters, there are two current ripple periods with different magnitudes in one switching period, both of which can generate the iron loss in the converter. In this paper, a dual current ripple envelopes (DCRE) method is proposed to accurately outline the two current ripples in each switching period. A novel iron loss estimation method is further presented based on the DCRE and the existing iron loss characteristics. Adopting the DCRE method, the influence of pulse width modulation (PWM) schemes, voltage levels, and the amplitude of output current, can be easily evaluated, which provides a satisfactory guidance to the design of the inductor. The effectiveness of the proposed DCRE and iron loss estimation method is verified by the numerical simulation and the experimental test on a three phase grid connected converter.", "author_names": [ "Rende Zhao", "Xianqiang Jiang", "Hailiang Xu", "Qingzeng Yan", "Yansong Wang" ], "corpus_id": 207973103, "doc_id": "207973103", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "An Iron Loss Estimation Method Based on Dual Current Ripple Envelopes for Three Phase Two Level Grid Connected Converters", "venue": "IEEE Access", "year": 2019 }, { "abstract": "Satellite DC/DC power converters are required to have EMI compatibility as well as high reliability. Since the EMI noise level of the DC/DC converter should be satisfied within the electromagnetic compatibility (EMC) requirement, it is essential to have a large EMI filter in front of it. For fundamentally addressing this problem, the zero ripple reduction technique has been studied to significantly reduce the ripple on the converter input current, which is the major source of the EMI noise. The active clamp forward with a continuous input current waveform (CACF) converter, which is applied the zero ripple technique on the primary side of the converter, shows greatly reduced input current ripple. In this paper, it is compared that the EMI noise measurement for the CACF converter and the conventional active clamp forward (ACF) converter to confirm the improved EMI noise performance of the CACF converter.", "author_names": [ "Nayoung Lee", "Tae-Yoon Kim", "Ju-Young Lee", "Sang-Kyoo Han", "Tae-Jin Chung", "Jae-dong Choi" ], "corpus_id": 209383255, "doc_id": "209383255", "n_citations": 1, "n_key_citations": 1, "score": 0, "title": "Improved EMI noise performance by the reduced input ripple of the Satellite converter", "venue": "2019 European Space Power Conference (ESPC)", "year": 2019 }, { "abstract": "The influence of a filter inductor on the steady state performance of a parallel type resonant converter is elaborated and analyzed in this paper. By steady state operation analysis, it is shown that the ripple current of the filter inductor results in an inaccurate prediction of fundamental harmonic approximation (FHA) and such problem would become serious when the filter inductance is small. In order to portray such feature, an improved fundamental harmonic approximation (IFHA) is proposed. Unlike an FHA equivalent circuit, an equivalent inductor is added to the ac resistance parallelly in an IFHA equivalent circuit. Due to that, the equivalent inductor branch takes account of the ripple current of the filter inductor, and the IFHA is expected to own higher accuracy and can be used in a parameter design procedure. In this paper, the equivalent inductor expressions of full bridge rectifier and current doubler rectifier are derived as examples. In order to verify the theoretical analysis, a 500 W LCC resonant converter is built as a prototype. The close loop experiment results show that small filter inductance would lead to the failure of output voltage regulation and hard switching operation of power switches. And open loop experiment results show the IFHA gives more accurate predictions than those of FHA.", "author_names": [ "Yiming Chen", "Jianping Xu", "Jin Sha", "Leiming Lin", "Jing Cao" ], "corpus_id": 59620198, "doc_id": "59620198", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "An Improved Fundamental Harmonic Approximation to Describe Filter Inductor Influence on Steady State Performance of Parallel Type Resonant Converter", "venue": "IEEE Transactions on Power Electronics", "year": 2019 } ]
polymer material based chemosensor
[ { "abstract": "The need to develop inexpensive renewable energy sources stimulates scientific research for efficient, low cost photovoltaic devices.1 The organic, polymer based photovoltaic elements have introduced at least the potential of obtaining cheap and easy methods to produce energy from light.2 The possibility of chemically manipulating the material properties of polymers (plastics) combined with a variety of easy and cheap processing techniques has made polymer based materials present in almost every aspect of modern society.3 Organic semiconductors have several advantages: (a) lowcost synthesis, and (b) easy manufacture of thin film devices by vacuum evaporation/sublimation or solution cast or printing technologies. Furthermore, organic semiconductor thin films may show high absorption coefficients4 exceeding 105 cm 1, which makes them good chromophores for optoelectronic applications. The electronic band gap of organic semiconductors can be engineered by chemical synthesis for simple color changing of light emitting diodes (LEDs).5 Charge carrier mobilities as high as 10 cm2/V,s6 made them competitive with amorphous silicon.7 This review is organized as follows. In the first part, we will give a general introduction to the materials, production techniques, working principles, critical parameters, and stability of the organic solar cells. In the second part, we will focus on conjugated polymer/fullerene bulk heterojunction solar cells, mainly on polyphenylenevinylene (PPV) derivatives/(1 (3 methoxycarbonyl) propyl 1 phenyl[6,6]C61) (PCBM) fullerene derivatives and poly(3 hexylthiophene) (P3HT)/PCBM systems. In the third part, we will discuss the alternative approaches such as polymer/polymer solar cells and organic/inorganic hybrid solar cells. In the fourth part, we will suggest possible routes for further improvements and finish with some conclusions. The different papers mentioned in the text have been chosen for didactical purposes and cannot reflect the chronology of the research field nor have a claim of completeness. The further interested reader is referred to the vast amount of quality papers published in this field during the past decade.", "author_names": [ "Serap Gunes", "Helmut Neugebauer", "Niyazi Serdar Sariciftci" ], "corpus_id": 81670, "doc_id": "81670", "n_citations": 5373, "n_key_citations": 45, "score": 0, "title": "Conjugated polymer based organic solar cells.", "venue": "Chemical reviews", "year": 2007 }, { "abstract": "The synthesis, spectroscopy, and fluorescence quenching behavior of pentiptycene derived phenyleneethynylene polymers, 1 3, are reported. The incorporation of rigid three dimensional pentiptycene moieties into conjugated polymer backbones offers several design advantages for solid state (thin film) fluorescent sensory materials. First, they prevent p stacking of the polymer backbones and thereby maintain high fluorescence quantum yields and spectroscopic stability in thin films. Second, reduced interpolymer interactions dramatically enhance the solubility of polymers 1 3 relative to other poly(phenyleneethynylenes) Third, the cavities generated between adjacent polymers are sufficiently large to allow diffusion of small organic molecules into the films. These advantages are apparent from comparisons of the spectroscopic and fluorescence quenching behavior of 1 3 to a related planar electron rich polymer 4. The fluorescence attenuation (quenching) of polymer films upon exposure to analytes depends on seve.", "author_names": [ "Jye-Shane Yang and", "Timothy M Swager" ], "corpus_id": 54843240, "doc_id": "54843240", "n_citations": 937, "n_key_citations": 6, "score": 0, "title": "Fluorescent Porous Polymer Films as TNT Chemosensors: Electronic and Structural Effects", "venue": "", "year": 1998 }, { "abstract": "The gas sensors fabricated by using conducting polymers such as polyaniline (PAni) polypyrrole (PPy) and poly (3,4 ethylenedioxythiophene) (PEDOT) as the active layers have been reviewed. This review discusses the sensing mechanism and configurations of the sensors. The factors that affect the performances of the gas sensors are also addressed. The disadvantages of the sensors and a brief prospect in this research field are discussed at the end of the review.", "author_names": [ "Hua Bai", "Gaoquan Shi" ], "corpus_id": 10394983, "doc_id": "10394983", "n_citations": 1142, "n_key_citations": 12, "score": 0, "title": "Gas Sensors Based on Conducting Polymers", "venue": "Sensors (Basel, Switzerland)", "year": 2007 }, { "abstract": "A new fluorescent sensor based on rhodamine B for Pb2+ was synthesized. The new fluorescent sensor showed an extreme selectivity for Pb2+ over other metal ions examined in acetonitrile. Upon the addition of Pb2+ an overall emission change of 100 fold was observed, and the selectivity was calculated to be 200 times that of Zn2+ The signal transduction occurs via of reversible CHEF (chelation enhanced fluorescence) with this inherent quenching metal ion.", "author_names": [ "Ji Young Kwon", "Yun Jung Jang", "Yoon Ju Lee", "Kwan Mook Kim", "Mi Sook Seo", "Wonwoo Nam", "Juyoung Yoon" ], "corpus_id": 27886210, "doc_id": "27886210", "n_citations": 551, "n_key_citations": 1, "score": 0, "title": "A highly selective fluorescent chemosensor for Pb2+", "venue": "Journal of the American Chemical Society", "year": 2005 }, { "abstract": "Fluorescence is a leading signal transduction method for the formation of chemosensory devices.1,2 Conjugated polymer based fluorescent chemosensors have been proven to further amplify this inherently sensitive method.2 Although solid state (thin film) fluorescent chemosensory devices are generally required, most systems have limited solid state utility with the lack of stable (reproducible) spectroscopic features and low fluorescence quantum yields, presumably due to the excimer formation and selfquenching.3,4 These processes have been an impediment to other applications of conjugated polymers and general solutions also have implications for electroluminescent polymer devices.4 We report herein an approach to stable fluorescent conjugated polymer films by the incorporation of the rigid three dimensional pentiptycene moieties,5 1, which prevent p stacking or excimer formation. In comparison to the planar model polymer 3, thin films of the pentiptycene polymer, 2, display enhanced fluorescence quantum yield and stability. Moreover, their potential for the trace detection of high explosives such as 2,4,6 trinitrotoluene (TNT) is also reported.6 Polymer 2 has unprecedented high sensitivity as an artificial fluorescent chemosensor for the vapors of TNT and 2,4 dinitrotoluene (DNT)", "author_names": [ "Jye-Shane Yang", "Timothy M Swager" ], "corpus_id": 55610281, "doc_id": "55610281", "n_citations": 630, "n_key_citations": 3, "score": 0, "title": "Porous Shape Persistent Fluorescent Polymer Films: An Approach to TNT Sensory Materials", "venue": "", "year": 1998 }, { "abstract": "Sensing of metal ions and anions is of great importance because of their widespread distribution in environmental systems and biological processes. Colorimetric and fluorescent chemosensors based on organic molecular species have been demonstrated to be effective for the detection of various ions and possess the significant advantages of low cost, high sensitivity, and convenient implementation. Of the available classes of organic molecules, porphyrin analogues possess inherently many advantageous features, making them suitable for the design of ion chemosensors, with the targeted sensing behavior achieved and easily modulated based on their following characteristics: (1) NH moieties properly disposed for binding of anions through cooperative hydrogen bonding interactions; (2) multiple pyrrolic N atoms or other heteroatoms for selectively chelating metal ions; (3) variability of macrocycle size and peripheral substitution for modulation of ion selectivity and sensitivity; and (4) tunable near infrared emission and good biocompatibility. In this Review, design strategies, sensing mechanisms, and sensing performance of ion chemosensors based on porphyrin analogues are described by use of extensive examples. Ion chemosensors based on normal porphyrins and linear oligopyrroles are also briefly described. This Review provides valuable information for researchers of related areas and thus may inspire the development of more practical and effective approaches for designing high performance ion chemosensors based on porphyrin analogues and other relevant compounds.", "author_names": [ "Yubin Ding", "Weihong Zhu", "Yongshu Xie" ], "corpus_id": 29856938, "doc_id": "29856938", "n_citations": 332, "n_key_citations": 0, "score": 1, "title": "Development of Ion Chemosensors Based on Porphyrin Analogues.", "venue": "Chemical reviews", "year": 2017 }, { "abstract": "The cyanine platforms including cyanine, hemicyanine, and squaraine are good candidates for developing chemosensors because of their excellent photophysical properties, outstanding biocompatibility, and low toxicity to living systems. A huge amount of research work involving chemosensors based on the cyanine platforms has emerged in recent years. This review focuses on the development from 2000 to 2015, in which cyanine, hemicyanine, and squaraine sensors will be separately summarized. In each section, a systematization according to the type of detection mechanism is established. The basic principles about the design of the chemosensors and their applications as bioimaging agents are clearly discussed. In addition, we emphasize the advances that have been made in improving the detection performance through incorporation of the chemosensors into nanoparticles.", "author_names": [ "Wen Sun", "Shigang Guo", "Chong Hu", "Jiangli Fan", "Xiaojun Peng" ], "corpus_id": 34815610, "doc_id": "34815610", "n_citations": 455, "n_key_citations": 0, "score": 0, "title": "Recent Development of Chemosensors Based on Cyanine Platforms.", "venue": "Chemical reviews", "year": 2016 }, { "abstract": "A melamine piezomicrogravimetric (acoustic) chemosensor using a molecularly imprinted polymer (MIP) film has been devised and tested. The MIP films were prepared by electropolymerization of the melamine complexed by the functional monomer of the bis(bithiophene) derivative bearing an 18 crown 6 substituent 4. The structure of the MIP melamine complex was visualized by the DFT B3LYP/3 21G( energy optimization calculations. The sensitivity and selectivity of the MIP film was improved by cross linking the polymer with the bithianaphthene monomer 5 and the presence of the porogenic ionic liquid in the prepolymerization solution. After electropolymerization, the melamine template was extracted from the MIP film with an aqueous strong base solution. The measurements of UV vis spectroscopy, X ray photoelectron spectroscopy (XPS) DPV, and EIS as well as scanning electrochemical microscopy (SECM) imaging confirmed extraction of the melamine template from the MIP film and then rebinding of the melamine analyte while the film relative roughness and porosity was determined by atomic force microscopy (AFM) and scanning electron microscopy (SEM) imaging, respectively. The analytical as well as kinetic and thermodynamic parameters of the chemosensing were assessed under flow injection analysis (FIA) conditions with piezoelectric microgravimetry (PM) detection. The linear concentration range for melamine detection was 5 nM to at least 1 mM with a limit of detection of approximately 5 nM. The chemosensor successfully discriminated the cyanuric acid, cyromazine, and ammeline interfering agents.", "author_names": [ "Agnieszka J Pietrzyk", "Wlodzimierz Kutner", "Raghu Chitta", "Melvin E Zandler", "Francis D'Souza", "Francesco Sannicolo", "Patrizia Romana Mussini" ], "corpus_id": 26119410, "doc_id": "26119410", "n_citations": 102, "n_key_citations": 3, "score": 0, "title": "Melamine acoustic chemosensor based on molecularly imprinted polymer film.", "venue": "Analytical chemistry", "year": 2009 }, { "abstract": "Conducting polymer (CP) hybrids, which combine CPs with heterogeneous species, have shown strong potential as electrical transducers in chemosensors. The charge transport properties of CPs are based on chemical redox reactions and provide various chemo electrical signal transduction mechanisms. Combining CPs with other functional materials has provided opportunities to tailor their major morphological and physicochemical properties, often resulting in enhanced sensing performance. The hybrids can provide an enlarged effective surface area for enhanced interaction and chemical specificity to target analytes via a new signal transduction mechanism. Here, we review a selection of important CPs, including polyaniline, polypyrrole, polythiophene and their derivatives, to fabricate versatile organic and inorganic hybrid materials and their chemo electrical sensing performance. We focus on what benefits can be achieved through material hybridization in the sensing application. Moreover, state of the art trends in technologies of CP hybrid sensors are discussed, as are limitations and challenges.", "author_names": [ "Seon Joo Park", "Chul Soon Park", "Hyeonseok Yoon" ], "corpus_id": 8109272, "doc_id": "8109272", "n_citations": 81, "n_key_citations": 0, "score": 0, "title": "Chemo Electrical Gas Sensors Based on Conducting Polymer Hybrids", "venue": "Polymers", "year": 2017 }, { "abstract": "During the past decade, fluorescent chemosensors have become an important research field of supramolecular chemistry and have attracted great attention because of their simplicity, high selectivity and sensitivity in fluorescent assays. In the design of new fluorescent chemosensors, exploration of new sensing mechanisms between recognition and signal reporting units is of continuing interest. Based on different photophysical processes, conventional sensing mechanisms including photo induced electron transfer (PET) intramolecular charge transfer (ICT) metal ligand charge transfer (MLCT) twisted intramolecular charge transfer (TICT) electronic energy transfer (EET) fluorescence resonance energy transfer (FRET) and excimer/exciplex formation have been investigated and reviewed extensively in the literature. This tutorial review will mainly focus on new fluorescent sensing mechanisms that have emerged in the past five years, such as aggregation induced emission (AIE) and C=N isomerization, which can be ascribed to fluorescence changes via conformational restriction. In addition, excited state intramolecular proton transfer (ESIPT) has not been well reviewed yet, although a number of chemosensors based on the ESIPT mechanism have been reported. Thus, ESIPT based chemosensors have been also summarized in this review.", "author_names": [ "Jiasheng Wu", "Weimin Liu", "Jiechao Ge", "Hongyan Zhang", "Pengfei Wang" ], "corpus_id": 11460741, "doc_id": "11460741", "n_citations": 1252, "n_key_citations": 1, "score": 0, "title": "New sensing mechanisms for design of fluorescent chemosensors emerging in recent years.", "venue": "Chemical Society reviews", "year": 2011 } ]
Photonic Crystals PBG
[ { "abstract": "Abstract In this paper, the optical spectra of one dimensional photonic crystal (PCs) are numerically investigated in UV, Visible and Infrared ranges. PCs consisting of a HTc superconducting material (YaBa2Cu3O7) are sandwiched between dielectric layer (SiO2 or AlN) and semiconductor layer (GaAs) where superconducting layer is considered as defects. Using transfer matrix method, all the numerical results are performed and inferred that photonic band gap shifted to higher wavelengths by increasing the temperature. It is found that when the temperature increases the PBG shifted to a long wavelength. When the defect is used in structure as dielectric or superconductor, the peak appears in PBG and his value increases as the temperature increases.", "author_names": [ "Arafa H Aly", "S E -S Abdel Ghany", "" ], "corpus_id": 202950267, "doc_id": "202950267", "n_citations": 22, "n_key_citations": 0, "score": 1, "title": "Theoretical studies of hybrid multifunctional YaBa2Cu3O7 photonic crystals within visible and infra red regions", "venue": "", "year": 2020 }, { "abstract": "We present the structuring of different graded index materials in the form of one dimensional (1D) photonic crystals (PCs) for highly efficient light trapping and controlling photonic devices in terms of tuned and controlled photonic bandgap (PBG) performance. We consider hyperbolic, exponential, and linear refractive index variation in the graded index layer. We systematically study the influence of structural and grading parameters on the bandgap performance for two different graded photonic crystal (GPC) structures formed by stacking different graded index layers. Compared with conventional PCs, the GPC bandgaps can be changed and tuned by the refractive index profile of the graded index layer. We show that the number of bandgaps increases with the graded index layer thickness and the bandgap frequencies can be tuned by the grading profiles. We observe the sequential increment in bandwidth for the complete PBGs in the GPC structures with linear, exponential, and hyperbolic graded index materials. We also study the influence of the stacking pattern and grading profiles on the bandgap, phase shift, group velocity, delay time, and field distribution. The proposed GPC configurations facilitate the design of reflectors, multi channel filters, detectors, and other photonic devices. The study may also provide the basis of understanding of the influence of graded index materials on the PBG characteristics in the GPCs.", "author_names": [ "Bipin Kumar Singh", "Ashish Bijalwan", "Praveen C Pandey", "Vipul Rastogi" ], "corpus_id": 213363640, "doc_id": "213363640", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Multi channel photonic bandgap consequences in one dimensional linear, exponential, and hyperbolic graded index photonic crystals", "venue": "", "year": 2020 }, { "abstract": "The slow photon effect can significantly increase the effective optical path length of light and thereby enhance the interaction of light with matter, which would be realized by light propagating at the edges of the photonic band gap (PBG) in photonic crystals (PCs) In this paper, a novel anodic oxidation method with effective voltage pulse compensation was developed to prepare one dimensional titania nanotube photonic crystals (1D TiO2 NT PCs) with a high quality of PBG, which could be continuously adjusted and precisely tailored just by modulating the anodization parameters. With the increase of low voltage (Lv) duration, the precise blue shift of the PBG of 1D TiO2 NT PCs was recorded. Through the precise tailoring of PBG in bandgap engineering, the edges of the PBG could be designed and purposely tuned to overlap with the electronic band gap range of the TiO2 material, and the as prepared 1D TiO2 NT PCs were used as a photocatalyst to degrade methyl orange (MO) molecules due to the enhanced slow photon effect and scattering effect in their highly ordered channel structures. Meanwhile, strategies to enhance the slow photon effect at the edge of the PBG were discussed and evaluated in detail according to our experimental and simulated results. This study would provide a new guide to taking advantage of the slow photon effect to enhance the photocatalytic activities, photoluminescence, and performances of other optoelectronic devices.", "author_names": [ "Xiao-Tian Wang", "Xiao-Gang Wang", "Cheng-wei Wang" ], "corpus_id": 214172718, "doc_id": "214172718", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Bandgap engineering of TiO2nanotube photonic crystals for enhancement of photocatalytic capability", "venue": "", "year": 2020 }, { "abstract": "Abstract In this paper, different types of binary gases were detected by the silica photonic crystals (PCs) It is found that the regulation of gas sensing is very different when silica PCs exposure to different types of binary gases. Here, silica PCs were prepared by the vertical deposition method. The performance of gas sensing was monitored by the shift of photonic band gap (PBG) of PCs. It is noteworthy that we convert the shift of PBG into the volume fraction of adsorption in order to investigate the adsorption behavior. For small molecule gases, the maximum of adsorption volume fraction of binary gases is smaller than two of the single gases. While for volatile organic compounds (VOCs) the maximum of adsorption volume fraction of binary gases locates between the two individual gases. The different types of gases follow different adsorption model, which are discussed in this work.", "author_names": [ "Hu Wang", "Penghui Bai", "Juan Xie", "Lei Zhang", "Kai Lei", "Biao Liu", "Chenjie Wang", "Linghui Zhu", "Guangyong Wang" ], "corpus_id": 224873041, "doc_id": "224873041", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Gas sensing of silica photonic crystals for binary gases", "venue": "", "year": 2020 }, { "abstract": "Abstract The Graphene patch antennas is widely used due to high electrical conductivity, high mobility, and saturation velocity in THz band. In a Terahertz (THz) band, high gain antennas to be preferred to minimized the atmospheric attenuation and path losses. In this article, the enhanced radiation characteristics graphene based antenna array design concept is proposed by using homogeneous substrate, photonic band gap crystal (PBG) substrate and superstrated dielectric grating. The projected graphene based 2x1 patch array antennas works as a resonance patch with complementary split split split ring resonator (CSSSRR) for the frequency range from 0.84 THz to 0.94 THz. The tunable property of graphene material and PBG substrate are investigated by varying the chemical potential m c of graphene sheet and different radius of hollow cylinders respectively. The minimum return loss of 57.052 dB, peak gain of 14.69 dB and directivity of 15.5 dBi are achieved with the planned antenna employing with superstrated dielectric grating structures. The suggested 2x1 graphene patch antenna array are operating in low atmospheric attenuation window henceforth suitable for the application of medical imaging, threat detection, and THz wireless communication.", "author_names": [ "Ritesh Kumar Kushwaha", "P Karuppanan" ], "corpus_id": 204186201, "doc_id": "204186201", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Enhanced radiation characteristics of graphene based patch antenna array employing photonic crystals and dielectric grating for THz applications", "venue": "", "year": 2020 }, { "abstract": "Abstract Engineering of multi channel photonic band gap sensing consequences has been demonstrated in hyperbolic graded index materials embedded one dimensional (1 D) photonic crystal (PC) in the frequency 150 850 THz region. The multi channel photonic band gap sensing properties have been investigated by taking into account the reflection and photonic band gap (PBG) spectra of the proposed PC structures. For quarter wave stacking, we obtain single optical reflection band for band region 646.8 434.3 THz with the constituted normal layer refractive index 1.5. Band regions and bandwidths of the single PBG channel can be modulated by changing the refractive index of the constituted normal layer and grading parameter of the hyperbolic graded layer. The number of photonic bands increases with increasing the layer thickness of the GPC structures and leads to work as multi channel PBG sensors. The operation frequency of the multi channel PBG sensors can also be tuned by changing the constituted normal layer and grading parameter of the hyperbolic graded layer. These properties lead to design the tunable multi channel optical sensors/filters engineering. Moreover, the demonstration of the reflection phase shift, group velocity, group delay, and electric field distributions shows the effect of hyperbolic graded index materials on the propagation of light in 1 D PCs. With the engineering of tunable PBGs and structure controllability, hyperbolic graded index materials embedded 1 D PCs provide a promising way to fabricate tunable optical reflectors and multi channel optical sensors/filters for future optical devices.", "author_names": [ "Bipin Kumar Singh", "Vaishali A Bambole", "Vipul Rastogi", "Praveen C Pandey" ], "corpus_id": 218969449, "doc_id": "218969449", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Multi channel photonic bandgap engineering in hyperbolic graded index materials embedded one dimensional photonic crystals", "venue": "", "year": 2020 }, { "abstract": "All inorganic cesium lead halide perovskite semiconductors exhibit great potential for nanolasers, light emitting diodes, and solar cells, because of their unique properties including low threshold, high quantum efficiency and low cost. However, the high material refractive index of perovskite semiconductors hinders light extraction efficiency for photonic and illumination applications. In this paper, we demonstrate high light extraction efficiency achieved in CsPbBr2.75I0.25 two dimensional photonic crystals. The perovskite photonic crystals exhibit both emission rate inhibition and light energy redistribution simultaneously. We observed a 7.9 fold reduction of spontaneous emission rate with a slower decay in CsPbBr2.75I0.25 photonic crystals, because of the photonic bandgap effect (PBG) We also observed a 23.5 fold PL emission enhancement, as a result of light energy redistribution from 2D guided modes to vertical direction in perovskite photonic crystals thin films, indicating a high intrinsic light e.", "author_names": [ "Songyan Hou", "Aozhen Xie", "Zhenwei Xie", "Landobasa Y M Tobing", "Jin Zhou", "Liliana Tjahjana", "Junhong Yu", "Chathuranga Hettiarachchi", "Cuong Dang", "E H T Teo", "Muhammad Danang Birowosuto", "Hangzhou Wang" ], "corpus_id": 127760139, "doc_id": "127760139", "n_citations": 23, "n_key_citations": 0, "score": 0, "title": "Concurrent Inhibition and Redistribution of Spontaneous Emission from All Inorganic Perovskite Photonic Crystals", "venue": "ACS Photonics", "year": 2019 }, { "abstract": "A new structure to control the electromagnetic waves has been successfully designed for smart windows applications. The present photonic crystals (PCs) smart window is designed from a unit cell of two different materials such as A (metal) and B (superconductor) of thicknesses that repeated for N periods. The numerical results are investigated based on the characteristic matrix method. It was found that the angle of incidence has a significant effect on the transmission values. At 10o angle of incidence, we found more than 80% of the visible light and a near IR is transmitted whereas at 60o angle of incidence, the photonic band gap (PBG) begins to appear at wavelengths greater than 800 nm and the visible light transmittance remains more than 80% Also, the dependence of the transmittance values on the periodicity and thickness of the proposed design was investigated. The proposed structure could be of potential use as a smart window in low temperature applications and space industry.", "author_names": [ "Arafa H Aly", "Ayman A Ameen", "Hussein A Elsayed", "Sodky H Mohamed", "Mahi R Singh" ], "corpus_id": 126645207, "doc_id": "126645207", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "One Dimensional Metallo Superconductor Photonic Crystals as a Smart Window", "venue": "", "year": 2019 }, { "abstract": "Upconversion fluorescent material such as NaYF4:Yb/Re (Re is lanthanide ions) nanoparticles has considerable application prospect, but the fluorescence efficiency is usually too low. In this paper, an effective approach has been validated to enhance the fluorescence intensity of NaYF4:Yb/Re by coupling with SiO2 opal photonic crystals (PCs) NaYF4:Yb/Tm and NaYF4:Yb/Er were prepared by thermal decomposition method and ligand exchange, and then spin coated on the surface of SiO2 opal PCs with different photonic band gap (PBG) The PBG properties of PCs/UCNPs composite films were measured by transmission spectra. The effect of overlapping extent between PBG and UCNPs' emission on upconversion emission enhancement was studied through fluorescence spectra. The result shows that when the SiO2 opal PCs with the PBG at 448 nm were composited with NaYF4:Yb/Tm, the upconversion fluorescence at 450 nm was enhanced mostly, which is 34 fold. Similarly, the highest enhancement, 23 fold, was observed for fluorescence of NaYF4:Yb/Er at 541 nm when composited with SiO2 opal PCs having PBG at 544 nm. According to the analysis, the upconversion fluorescence can be enhanced through coupling with PCs by utilizing the light reflection and light localization effect of PCs. At the same time, the highest enhancement is obtained when the PBG of PCs is exactly overlapping with the wavelength of upconversion fluorescence. Our study potentially will contribute to promoting the sooner practical application of upconversion nanoparticles.", "author_names": [ "Yihao Shi", "Fuqing Zhang", "Jiao Xu", "Kaihua Zhou", "Chen Chen", "Jian Cheng", "Ping Li" ], "corpus_id": 140046646, "doc_id": "140046646", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Upconversion fluorescence enhancement of NaYF4:Yb/Re nanoparticles by coupling with SiO2 opal photonic crystals", "venue": "Journal of Materials Science", "year": 2019 }, { "abstract": "Abstract In this paper, we have theoretically investigated the optical spectra of all superconducting aperiodic photonic crystals comprising from different superconductors namely high high, low low and high low temperature configurations. Also, the name Octonacci is composed of Octo from octagonal and acci from the Fibonacci sequence, however, the Octonacci sequence has a geometric origin. In order to show the difference between TE and TM polarized lightwaves, we have analyzed both the influence of the incident angle and temperature of light wave on the PBGs as well as transmittance resonance peaks. By the way, the possibility of obtaining deep photonic band gap (PBG) has been provided for both TE and TM polarizations for the most incident angles. This study also investigates the effect of generation number of the Octonacci sequence on the PBG spectrum within the visible range. The results show that optical performances of Octonacci all superconducting aperiodic photonic crystals are higher than Fibonacci ones even with upper generations. Finally, to show the impact of the results, we have made a comparison between this new investigating quasi periodic sequence and periodic all superconducting ones.", "author_names": [ "Mehdi Zamani", "Mansoureh Amanollahi", "Abdesselam Hocini" ], "corpus_id": 125835217, "doc_id": "125835217", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Photonic band gap spectra in Octonacci all superconducting aperiodic photonic crystals", "venue": "Physica B: Condensed Matter", "year": 2019 } ]
solvothermal Route to Semiconductor Nanowires
[ { "abstract": "Solvothermal synthesis is an important technology for the preparation of nanowires at low temperature. Nanowires can grow as long as 100 mm with the aid of polymer matrix, and under the pressure generated by solvothermal reactions, the as prepared nanowires are well crystallized. For water sensitive reactions, solvothermal reactions can fully avoid the presence of water. We discuss here the synthesis of a variety of nanowire structures, including CdS CdSe core sheath nanowires and very long CdS nanowires, and the solvothermal closure of PbS nanowires. Now that an appropriate procedure has been established, the solvothermal reactions are efficient and time saving.", "author_names": [ "Kaibin Tang", "Yitai Qian", "Jinghui Zeng", "Xiaogang Yang" ], "corpus_id": 94087356, "doc_id": "94087356", "n_citations": 134, "n_key_citations": 0, "score": 1, "title": "Solvothermal Route to Semiconductor Nanowires", "venue": "", "year": 2003 }, { "abstract": "", "author_names": [ "Kaibin Tang", "Yitai Qian", "Jing-Hui Zheng", "Xiaogang Yang" ], "corpus_id": 197215117, "doc_id": "197215117", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Solvothermal Route to Semiconductor Nanowires", "venue": "", "year": 2003 }, { "abstract": "The solvothermal/hydrothermal method is an important technology for producing semiconductor nanowires at low temperature. This paper presents an integrated discussion of nanowire growth, mainly from four aspects in the solvothermal/hydrothermal process. These aspects, including materials with highly anisotropic crystal structures, coordination directing/mixed solvents, surfactants/capping reagents, and reaction at relatively high temperature, have a key effect on nanowire formation in the solvothermal/hydrothermal process. These factors have instructional significance for nanowire synthesis and research of their growth process in the future.", "author_names": [ "Guifu Zou", "Hui Li", "Yuanguang Zhang", "Kan Xiong", "Yitai Qian" ], "corpus_id": 95705738, "doc_id": "95705738", "n_citations": 88, "n_key_citations": 1, "score": 0, "title": "Solvothermal/hydrothermal route to semiconductor nanowires", "venue": "", "year": 2006 }, { "abstract": "Ternary Cu Bi S based compounds have been thought to be alternative materials for well known CuInS2 because of their abundance. Cu Bi S based nanomaterials have been less studied. We here report the synthesis, optical and electrical properties of single crystal Cu4Bi4S9 nanowires. High quality Cu4Bi4S9 nanowires were synthesized through a modified solvothermal route by controlling the reaction sources and temperature. The optical bandgap for Cu4Bi4S9 nanowires were determined by using UV vis NIR and cyclic voltammetry techniques. Single nanowire devices were fabricated by using lithographic techniques. The devices exhibit photoconductive response with high external quantum efficiency (2.9 x 108% Temperature dependent electrical transport properties were also investigated. We observed that the transport properties of Cu4Bi4S9 nanowire show typical semiconductor behaviour in the temperature region 10 140 K and metal like character in the temperature region of 150 300 K. The carrier transport in Cu4Bi4S9 nanowires can be described by the small polaron model in temperature region of 60 140 K and the variable range hopping mechanism in temperature region of 10 50 K. We further studied the properties of Cu4Bi4S9 nanowires in field emission devices. The devices exhibit a relatively low turn on field (6.9 V mm 1) The potential applications of Cu4Bi4S9 nanowires as field emitting materials and light absorbers in detectors are indicated.", "author_names": [ "Jing Li", "Haizheng Zhong", "Huijuan Liu", "Tianyou Zhai", "Xi Wang", "Meiyong Liao", "Yoshio Bando", "Ruibin Liu", "Bingsuo Zou" ], "corpus_id": 93629860, "doc_id": "93629860", "n_citations": 23, "n_key_citations": 0, "score": 0, "title": "One dimensional ternary Cu Bi S based semiconductor nanowires: synthesis, optical and electrical properties", "venue": "", "year": 2012 }, { "abstract": "A novel one step soft solution processing route called the solvothermal copolymerization technique was successfully developed for in situ fabrication of polystyrene (PS)/CdS nanocomposites embedded with CdS nanowires in ethylenediamine media at lower temperatures (80 140 degC) In this route, the polymerization of the monomers and the formation of the CdS nanocrystallites occur simultaneously in a certain temperature range. The results of X ray powder diffraction, transmission electron microscopy, and high resolution transmission electron microscopy confirmed that the embedded CdS nanowires, with diameters of 4 15 nm and lengths up to several micrometers, have [001] preferential orientation. Both temperature and solvent were found to play a key role in the synthesis of the nanocomposites. The produced novel hybrid nanocomposites display obvious quantum size effects and interesting fluorescence features. The spectroscopic properties of the PS/CdS nanowire nanocomposites were found to be sensitive to syntheti.", "author_names": [ "Shuhong Yu", "Masahiro Yoshimura", "Jose Maria Calderon Moreno", "Takeshi Fujiwara", "Takahiro Fujino", "Ryo Teranishi" ], "corpus_id": 95623014, "doc_id": "95623014", "n_citations": 61, "n_key_citations": 0, "score": 0, "title": "IN SITU FABRICATION AND OPTICAL PROPERTIES OF A NOVEL POLYSTYRENE/SEMICONDUCTOR NANOCOMPOSITE EMBEDDED WITH CDS NANOWIRES BY A SOFT SOLUTION PROCESSING ROUTE", "venue": "", "year": 2001 }, { "abstract": "Soft chemistry has emerged as an important means of generating nanocrystals, nanowires and other nanostructures of semiconducting materials. We describe the synthesis of CdS and other metal chalcogenide nanocrystals by a solvothermal route. We also describe the synthesis of nanocrystals of AlN, GaN and InN by the reaction of hexamethyldisilazane with the corresponding metal chloride or metal cupferronate under solvothermal conditions. Nanowires of Se and Te have been obtained by a self seeding solution based method. A single source precursor based on urea complexes of metal chlorides gives rise to metal nitride nanocrystals, nanowires and nanotubes. The liquidliquid interface provides an excellent medium for preparing single crystalline films of metal chalcogenides.", "author_names": [ "Ujjal K Gautam", "Kripasindhu Sardar", "Francis Leonard Deepak", "C N R Rao" ], "corpus_id": 53487288, "doc_id": "53487288", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Soft chemical routes to semiconductor nanostructures", "venue": "", "year": 2005 }, { "abstract": "In an effort to find a simple and common single source precursor route for the group 13 metal nitride semiconductor nanostructures, the complexes formed by the trichlorides of Al, Ga and In with urea have been investigated. The complexes, characterized by X ray crystallography and other techniques, yield the nitrides on thermal decomposition. Single crystalline nanowires of AlN, GaN and InN have been deposited on Si substrates covered with Au islands by using the complexes as precursors. The urea complexes yield single crystalline nanocrystals under solvothermal conditions. The successful synthesis of the nanowires and nanocrystals of these three important nitrides by a simple single precursor route is noteworthy and the method may indeed be useful in practice.", "author_names": [ "Kripasindhu Sardar", "Meenakshi Dan", "Birgit Schwenzer", "C N R Rao" ], "corpus_id": 93640009, "doc_id": "93640009", "n_citations": 73, "n_key_citations": 0, "score": 0, "title": "A simple single source precursor route to the nanostructures of AlN, GaN and InN", "venue": "", "year": 2005 }, { "abstract": "Quaternary semiconductor Cu2CoSnS4 single crystalline nanowires arrays have been prepared through a solvothermal synthetic route by using anodic aluminum oxide as a hard template. The as prepared Cu2CoSnS4 nanowires are uniform with a [112] growth direction. An optimal solvent of diethylenetriamine is critical for the formation of single crystalline Cu2CoSnS4 nanowires. The structure, morphology, composition, and optical absorption properties of the as prepared Cu2CoSnS4 nanowires were characterized by using X ray powder diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X ray spectroscopy, and UV/Vis spectroscopy. A thin film prepared from Cu2CoSnS4 single crystalline nanowires displayed a clear photoelectric response, which suggested its potential application in photovoltaic devices.", "author_names": [ "Liang Shi", "Ya'nan Li", "Haojun Zhu", "Quan Li" ], "corpus_id": 96774956, "doc_id": "96774956", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Well Aligned Quaternary Cu2CoSnS4 Single Crystalline Nanowires as a Potential Low Cost Solar Cell Material", "venue": "", "year": 2014 }, { "abstract": "Abstract Large scale high quality CdS nanowires with uniform diameter were synthesized by using a rapid and simple solvothermal route. Field emission scan electron microscopy (FESEM) and transmission electron microscopy (TEM) images show that the CdS nanowires have diameter of about 26 nm and length up to several micrometres. High resolution TEM (HRTEM) study indicates the single crystalline nature of CdS nanowires with an oriented growth along the c axis direction. The optical properties of the products were characterized by UV vis absorption spectra, photoluminescence spectra and Raman spectra. The resistivity, electron concentration and electron mobility of single NW are calculated by fitting the symmetric I V curves measured on single NW by the metal semiconductor metal model based on thermionic field emission theory.", "author_names": [ "Shancheng Yan", "Litao Sun", "Peng Qu", "Ninping Huang", "Yinchen Song", "Zhongdang Xiao" ], "corpus_id": 93975092, "doc_id": "93975092", "n_citations": 48, "n_key_citations": 1, "score": 0, "title": "Synthesis of uniform CdS nanowires in high yield and its single nanowire electrical property", "venue": "", "year": 2009 }, { "abstract": "Abstract Solvothermal technique, an one step soft solution processing route was successfully employed to synthesize single crystalline CdS nanowires in ethylenediamine medium at lower temperature (170 for 1 8 d. In this route, polyethylene glycol 400 (PEG400) was used as surfactant, which played a crucial role in preferentially oriented growth of semiconductor nanowires. Characterizations of as prepared CdS nanowires by X ray powder diffraction(XRD) transmission electron microscopy(TEM) indicate that the naonowires, with typical diameters of 20nm and lengths up to several micrometers, have preferential [001] orientation. Also, investigations into the physical properties of the CdS nanowires were conducted with UV Vis absorption spectroscopy and photoluminescence emission spectroscopy. The excitonic photo optical phenomena of the nanowires shows the potential in the practical applications.", "author_names": [ "Guoyue Xu", "Hanli Wang", "Chuanwei Cheng", "Haiqian Zhang", "Jie-ming Cao", "Guangbin Ji" ], "corpus_id": 94357434, "doc_id": "94357434", "n_citations": 33, "n_key_citations": 0, "score": 0, "title": "Synthesis of single crystalline CdS nanowires with polyethylene glycol 400 as inducing template", "venue": "", "year": 2006 } ]
Crystal growth Handbook
[ { "abstract": "Crystals are fascinating objects and this two volume handbook deals with the fundamental aspects of crystal growth: the part A deals with thermodynamics and kinetics, while part B deals with transport and stability. As the preface of the volume indicates, there are three facets, namely, the art, the science and the technology to growing crystals; this book, with the emphasis on the fundamentals, deals with the scientific aspects with a strong emphasis on applications. The scientific aspects of crystal growth are varied, complex and cover a wide range of areas, issues, problems and techniques. This handbook consists of 26 chapters and deals with (a) the thermodynamic and kinetic aspects such as phase equilibria, equilibrium shapes, nucleation, growth, rough smooth transition, (b) transport and stability aspects such as morphological stability, dendrites, grain growth and crystallisation, and, (c) modelling aspects such as ab initio, density functional theory, Monte Carlo simulations and phase field models. There are also a wide variety of materials that are dealt with including ice and snow, proteins, pharmaceutical crystals, colloids, alloys, silicon, semiconductor nanocrystals, quasicrystals and oxides. The first chapter of the handbook on the historical aspects serves as a nice starting point for many of these chapters that follow. The handbook deals with the theoretical and computational aspects as well as experiments of crystal growth in a very comprehensive and authoritative manner. The chapters are written in a lucid style and are easy to understand. The mathematical derivations are given in good amount of detail, making it easy to follow the logic and algebra. There are a large number of figures, diagrams and images in each chapter which helps in developing a clear understanding of the subject matter at hand. Finally, each chapter contains a large number of references and many of the chapters end with open questions and concluding remarks indicating future directions of research. The production quality of the book is good. On the whole, the book, in addition to being a handy reference for researchers working in the area, will also be a very good read to beginning graduate students working on different aspects of crystal growth and will make a good addition to libraries in, and catering to, departments of physics, chemistry, materials, earth and medical sciences, and other allied areas. Some chapters of the books will also be handy to those teachers teaching graduate level courses in materials science, solidification and crystal growth. Hence, I have no hesitations in recommending the book.", "author_names": [ "Mogadalai P Gururajan" ], "corpus_id": 125768117, "doc_id": "125768117", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Handbook of crystal growth, 2nd edition: Fundamentals IA: thermodynamics and kinetics Fundamentals IB: transport and stability (two book set) edited by T. Nishinaga", "venue": "", "year": 2017 }, { "abstract": "", "author_names": [ "Helmut Klapper" ], "corpus_id": 225045084, "doc_id": "225045084", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Springer Handbook of Crystal Growth ReadingSample", "venue": "", "year": 2017 }, { "abstract": "", "author_names": [ "Hiromoto Susawa" ], "corpus_id": 103467972, "doc_id": "103467972", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Reconsideration of Chapter 7 Crystal Growth in Oyobutsuri Handbook etc.", "venue": "", "year": 2015 }, { "abstract": "", "author_names": [ "Govindhan Dhanaraj", "Kullaiah Byrappa", "Vishwanath Prasad", "Michael Dudley" ], "corpus_id": 135767965, "doc_id": "135767965", "n_citations": 295, "n_key_citations": 5, "score": 0, "title": "Springer handbook of crystal growth", "venue": "", "year": 2010 }, { "abstract": "This chapter covers the field of bulk single crystals of materials used in electronics and optoelectronics. These crystals are used in both active and passive modes, that is, to produce devices directly in/on bulk grown slices of material, or as substrates in epitaxial growth, respectively. Single crystal material usually provides superior properties to polycrystalline or amorphous equivalents. The various bulk growth techniques are outlined, together with specific critical features, and examples are given of the types of materials, and their current typical sizes, grown by these techniques. Materials covered range from group IVs (Si, Ge, SiGe, diamond, SiC) group III Vs (e. g. such as GaAs, InP, nitrides, etc. group II IVs (e. g. CdTe, ZnSe, HgCdTe (MCT) etc. through to a wide range of oxide/halide/phosphate/borate/tungstate materials. This chapter is to be treated as a snapshot only; the interested reader is referred to the remainder of the chapters in this handbook for more specific growth and characterization details on the various materials outlined in this chapter. Neither does this chapter cover the more fundamental aspects of the growth of the particular materials covered; again the reader is referred to relevant chapters within the handbook, or to other sources of information in the general literature.", "author_names": [ "Peter Capper" ], "corpus_id": 135890186, "doc_id": "135890186", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Bulk Crystal Growth: Methods and Materials", "venue": "", "year": 2017 }, { "abstract": "This chapter covers the field of bulk single crystals of materials used in electronics and optoelectronics. These crystals are used in both active and passive modes, that is, to produce devices directly in/on bulk grown slices of material, or as substrates in epitaxial growth, respectively. Single crystal material usually provides superior properties to polycrystalline or amorphous equivalents. The various bulk growth techniques are outlined, together with specific critical features, and examples are given of the types of materials, and their current typical sizes, grown by these techniques. Materials covered range from group IVs (Si, Ge, SiGe, diamond, SiC) group III Vs (e.g. such as GaAs, InP, nitrides, etc. group II IVs (e.g. CdTe, ZnSe, HgCdTe (MCT) etc. through to a wide range of oxide/halide/phosphate/borate/tungstate materials. This chapter is to be treated as a snapshot only; the interested reader is referred to the remainder of the chapters in this handbook for more specific growth and characterization details on the various materials outlined in this chapter. Neither does this chapter cover the more fundamental aspects of the growth of the particular materials covered; again the reader is referred to relevant chapters within the handbook, or to other sources of information in the general literature. 12.1 Background. 269", "author_names": [ "Peter Capper" ], "corpus_id": 201862701, "doc_id": "201862701", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Bulk Crystal G 269 Part B 12 1 12 Bulk Crystal Growth Methods and Materials", "venue": "", "year": 2017 }, { "abstract": "This title covers quartz, zeolites, gemstones, perovskite type oxides, ferrite, carbon allotropes, complex coordinated compounds and many more products now being produced using hydrothermal technology. \"Handbook of Hydrothermal Technology\" brings together the latest techniques in this rapidly advancing field in one exceptionally useful, long needed volume. The handbook provides a single source for understanding how aqueous solvents or mineralizers work under temperature and pressure to dissolve and recrystallize normally insoluble materials, and decompose or recycle any waste material. The result, as the authors show in the book, is technologically the most efficient method in crystal growth, materials processing, and waste treatment.The book gives scientists and technologists an overview of the entire subject including: Evolution of the technology from geology to widespread industrial use; Descriptions of equipment used in the process and how it works; Problems involved with the growth of crystals, processing of technological materials, environmental and safety issues; and Analysis of the direction of today's technology. In addition, readers get a close look at the hydrothermal synthesis of zeolites, fluorides, sulfides, tungstates, and molybdates, as well as native elements and simple oxides. Delving into the commercial production of various types, the authors clarify the effects of temperature, pressure, solvents, and various other chemical components on the hydrothermal processes.", "author_names": [ "Kullaiah Byrappa", "Masahiro Yoshimura" ], "corpus_id": 4952089, "doc_id": "4952089", "n_citations": 201, "n_key_citations": 9, "score": 0, "title": "Handbook of Hydrothermal Technology: A Technology for Crystal Growth and Materials Processing", "venue": "", "year": 2001 }, { "abstract": "", "author_names": [ "Paul J Phillips" ], "corpus_id": 135722661, "doc_id": "135722661", "n_citations": 176, "n_key_citations": 10, "score": 0, "title": "Handbook of Crystal Growth", "venue": "", "year": 1993 }, { "abstract": "", "author_names": [ "A P Wheeler" ], "corpus_id": 96750831, "doc_id": "96750831", "n_citations": 74, "n_key_citations": 2, "score": 0, "title": "Handbook of Crystal Growth, Vol 1b", "venue": "", "year": 1993 }, { "abstract": "", "author_names": [ "Robert B Heimann" ], "corpus_id": 96771841, "doc_id": "96771841", "n_citations": 6, "n_key_citations": 2, "score": 0, "title": "Handbook of crystal growth. Vol. 3: Thin films and epitaxy. a: Basic techniques; b: Growth mechanisms and dynamics", "venue": "", "year": 1997 } ]
Organic tandem solar cells comprising polymer and small-molecule subcells
[ { "abstract": "In this work the authors report monolithic organic tandem solar cells. The front cell is fabricated from a blend of poly(3 hexylthiophene 2,5 diyl) and [6,6] phenyl C61 butyric acid methyl ester while a copper phthalocyanine/fullerene (CuPc/C60) bilayer is used for the back cell. An intermediate recombination zone is realized using two doped organic semiconductor layers and a thin noble metal interlayer. The active polymer layer thickness is optimized to ensure matching of the subcell currents. The open circuit voltage Voc=1V nearly reaches the sum of the open circuit voltages of each contributing cell.", "author_names": [ "Alexander Colsmann", "Johannes Junge", "Christian Kayser", "Uli Lemmer" ], "corpus_id": 96869151, "doc_id": "96869151", "n_citations": 89, "n_key_citations": 0, "score": 1, "title": "Organic tandem solar cells comprising polymer and small molecule subcells", "venue": "", "year": 2006 }, { "abstract": "In this study, we stacked a small molecule based cell onto another polymer based device to fabricate a tandem organic solar cell that extended the absorption range of the entire cell over a wider spectral range. Between the two subcells, we positioned a connecting structure comprising layers of Cs2CO3, Ag and MoO3. Current matching phenomena played an important role in determining the device efficiency. The judicious selection of subcells exhibiting superior current matching improved the performance of the tandem cell. Indeed, in the optimally performing tandem cells we obtained both a high open circuit voltage (1.21V) and an improved power conversion efficiency (1.81% From analyses of the surface morphology and transmission spectra of the middle Ag layers, we deduced that the main function of this film was to provide more sites for efficient recombination of holes and electrons. The thickness of this layer was limited by its transmittance. A thinner Ag layer allowed more light to be harvested by the top cell, increasing the overall performance of the tandem cell. (Some figures in this article are in colour only in the electronic version)", "author_names": [ "Fang-Chung Chen", "Cheng-hao Lin" ], "corpus_id": 54527869, "doc_id": "54527869", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Construction and characteristics of tandem organic solar cells featuring small molecule based films on polymer based subcells", "venue": "", "year": 2010 }, { "abstract": "Multilayer structures involving solution deposited polymer films are difficult to fabricate, not allowing for unrestricted designs of polymer based optoelectronic devices required for maximizing their performance. Here, we fabricate a hybrid organic tandem solar cell whose top and bottom subcells have polymer:fullerene and small molecules active layers, respectively, by a solvent free process based on transferring the polymer:fullerene layer from an elastomeric stamp onto a vacuum deposited bottom subcell. The interface between small molecule and transferred polymer:fullerene layers is void free at the nanoscale, allowing for efficient charge transport across the interface. Consequently, the transfer fabricated tandem cell has an open circuit voltage (VOC) almost identical to the sum of VOC values for the single junction devices. The short circuit current density (JSC) of the tandem cell is maximized by current matching achieved by varying the thickness of the small molecule active layer in the bottom subcell, which is verified by numerical simulations. The optimized transfer fabricated tandem cell, whose active layers are composed of poly[2,1,3 benzothiadiazole 4,7 diyl[4,4 bis(2 ethylhexyl) 4H cyclopenta[2,1 b:3,4 b']dithiophene 2,6 diyl][6,6] Phenyl C71 butyric acid methyl ester and Di [4 (N,N di p tolyl amino) phenyl]cyclohexane:C70, has VOC 1.46 V, JSC 8.48 mA/cm2, a fill factor of 0.51, leading to the power conversion efficiency of 6.26% the highest among small molecule polymer:fullerene hybrid tandem solar cells demonstrated so far.", "author_names": [ "Yoonseok Ka", "Hyejin Hwang", "Changsoon Kim" ], "corpus_id": 3315443, "doc_id": "3315443", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Hybrid Organic Tandem Solar Cell Comprising Small Molecule Bottom and Polymer:Fullerene Top Subcells Fabricated by Thin Film Transfer", "venue": "Scientific Reports", "year": 2017 }, { "abstract": "Polymer/small molecule parallel connected tandem organic solar cells are explored as a simple platform for high efficiency tandem solar cells that are not subject to complications associated with complex current matching or successive solution processing. In particular, MoOx/Ag/MoOx (MAM) trilayer electrodes are investigated as an intermediate electrode that connects a front subcell composed of a solution processed bulk heterojunction of poly{2,6' 4,8 di(5 ethylhexylthienyl) benzo[1,2 b;3,4 b]dithiophene alt 5 dibutyloctyl 3,6 bis(5 bromothiophen 2 yl)pyrrolo[3,4 c]pyrrole 1,4 dione} (PBDTT DPP) and the fullerene derivative [6,6] phenyl C61 butyric acid methyl ester (PCBM) and a back subcell composed of a thermally evaporated C70 layer doped with 1,1 bis (4 bis(4 methyl phenyl) amino phenyl) cyclohexane (TAPC) The effect of each MoOx layer is analyzed in terms of both optical and electrical properties. A joint theoretical and experimental study indicates that the electric field is distributed along the cell depth such that the photogenerated current of the front subcell depends on the thickness of both MoOx layers, with a varied interference effect, and that of the back subcell depends primarily on the thickness of the adjacent MoOx layer, with a varied cavity resonance effect. Based on optimized conditions of MAM electrodes, parallel tandem hybrid organic solar cells having higher power conversion efficiency than that of single junction cells are successfully realized.", "author_names": [ "Soohyun Lee", "Tae Eui Kang", "Donggeon Han", "Hoyeon Kim", "Bumjoon J Kim", "Jongjin Lee", "Seunghyup Yoo" ], "corpus_id": 93481573, "doc_id": "93481573", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Polymer/small molecule parallel tandem organic solar cells based on MoOx Ag MoOx intermediate electrodes", "venue": "", "year": 2015 }, { "abstract": "Three furan fused boron dipyrromethenes (BODIPYs) with a CF3 group on the meso carbon are synthesized as near infrared absorbing materials for vacuum processable organic solar cells. The best single junction device reaches a short circuit current (jsc) of 13.3 mA cm 2 and a power conversion efficiency (PCE) of 6.1% These values are highly promising for an electron donor material with an absorption onset beyond 900 nm. In a tandem solar cell comprising a NIR BODIPY subcell and a matching \"green\" absorber subcell, complementary absorption is achieved, resulting in PCE of ~10%", "author_names": [ "Tian-Yi Li", "Toni Meyer", "Zaifei Ma", "Johannes Benduhn", "Christian Korner", "Olaf Zeika", "Koen Vandewal", "Karl Leo" ], "corpus_id": 207183753, "doc_id": "207183753", "n_citations": 38, "n_key_citations": 0, "score": 0, "title": "Small Molecule Near Infrared Boron Dipyrromethene Donors for Organic Tandem Solar Cells.", "venue": "Journal of the American Chemical Society", "year": 2017 }, { "abstract": "Combining wide and narrow band gap absorbers in tandem solar cells is a promising approach to improve the energy conversion of sun light. In this work, we present hybrid tandem devices comprising monolithically connected copper indium gallium diselenide (CIGS) bottom cells and polymer top cells. The thin polymer:fullerene bulk heterojunction absorber layers were transferred onto the rough CIGS surface by a soft contact lamination technique. Sputtered or solution deposited top cathodes complete the tandem devices with enhanced open circuit voltages.", "author_names": [ "Manuel Reinhard", "Paul Sonntag", "Ralph Eckstein", "Linda Burkert", "Andreas Bauer", "Bernhard Dimmler", "Uli Lemmer", "Alexander Colsmann" ], "corpus_id": 121190407, "doc_id": "121190407", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Monolithic hybrid tandem solar cells comprising copper indium gallium diselenide and organic subcells", "venue": "", "year": 2013 }, { "abstract": "The rapid development of perovskite solar cells is beyond our imagination. The power conversion efficiency (PCE) of organic inorganic hybrid perovskite solar cells has reached 25.5% (https:/www.nrel.gov/pv/cell efficiency.html) However, the unsatisfactory stability of hybrid perovskites is an obstacle for their commercialization, which results from the volatile and hygroscopic organic cations[1] Recently, inorganic perovskites (CsPbIxBr3 x) are receiving more and more attention due to their good thermal stability[2] Among them, CsPbI2Br is the most popular material for solar cells due to the appropriate Goldschmidt tolerance factor[3, 4] But the photovoltaic performance of CsPbI2Br is much lower than many other perovskites due to its large bandgap (1.92 eV) which means it can only absorb the light below 650 nm, leading to low photocurrent[5] Narrow bandgap organic solar cells have much broader photoresponse than CsPbI2Br solar cells, but their relatively high energy loss and insufficient absorption for the short wavelength light limit their PCE. Making tandem solar cells is an effective approach to break the efficiency limit. Tandem solar cells based on perovskite/silicon[6] perovskite/Cu(In,Ga)Se2 (CIGS)[7] perovskite/perovskite[8] and perovskite/organic[9] structures have been reported. Compared with perovskite/silicon and perovskite/CIGS tandem cells, perovskite/perovskite and perovskite/organic tandem cells have the advantage of low temperature solution processing. Perovskite/perovskite tandem solar cells with tin containing perovskite cell as the rear cell offered a certified PCE of 24.2% which is the highest PCE for perovskite/perovskite tandem solar cells so far[8] But it is hard to obtain long term stable tincontaining perovskites because Sn2+ is easy to be oxidized to Sn4+ Recently, the fast development of organic solar cells with narrow bandgap non fullerene acceptors provides new choice for tandem cells[10] After we reported the first two terminal inorganic perovskite/organic tandem solar cells[5] the PCE of inorganic perovskite/organic tandem cells increased from 15.04% to 18.38%[11] via using better perovskite and organic subcells. But the PCEs are still much lower than the other perovskite based tandem cells, which may be due to the lack of high performance organic solar cells. Recently, we developed a new polymer donor D18 for organic solar cells, demonstrating a PCE of 18.56% which is the highest PCE for organic solar cells to date[12, 13] Introducing high performance D18:Y6 cells into inorganic perovskite/organic tandem cells may further improve the PCE. In this communication, we report an inorganic perovskite/organic tandem solar cell with a CsPbI2Br front cell and a D18:Y6 rear cell. The energy loss in the tandem cell was reduced by using SnO2/ZnO electron transport layer. We optimized the photocurrent matching of the two subcells by adjusting the thickness of CsPbI2Br layer and D18:Y6 layer. The tandem solar cells delivered a record PCE of 20.18% The active layer for the organic solar cells consists of a wide bandgap polymer D18 (Eg 1.98 eV)[12] and a narrow bandgap non fullerene small molecule Y6 (Eg 1.81 eV)[14] (Fig. 1(a) The D18:Y6 blend film presents an absorption peak at 810 nm and an absorption onset at 931 nm (Fig. 1(b) The CsPbI2Br film shows an absorption onset at 650 nm and a shoulder peak at 628 nm. CsPbI2Br can compensate the absorption of D18:Y6 below 628 nm, leading to better light harvesting when applied in a tandem structure. The CsPbI2Br cells and D18:Y6 cells (Fig. S1) were fabricated to find the suitable charge transport materials and preparation conditions. Unlike the frequently used SnO2, SnO2/ZnO was used as electron transport layer. The CsPbI2Br cells with SnO2/ZnO electron transport layer show enhanced open circuit voltage (Voc) and short circuit current density (Jsc) (Fig. S2) suggesting reduced energy loss in the cells. The best CsPbI2Br cell and D18:Y6 cell gave PCEs of 14.48% and 15.23% respectively (Fig. S3 and Table S1) The CsPbI2Br cells show external quantum efficiency (EQE) above 80% at 390 640 nm (Fig. S3(b) The high EQE before 640 nm and high Voc for CsPbI2Br cell make it suitable to be the front cell in a tandem cell. The D18:Y6 cell presents broad photoresponse up to 970 nm, leading to high integrated current density (23.43 mA cm 2) than the CsPbI2Br cell (14.56 mA cm 2) The high EQE of D18:Y6 cell beyond 640 nm makes it suitable to be the rear cell. The tandem cells were fabricated with the structure shown in Fig. S4(a) The SnO2/ZnO layer, CsPbI2Br layer, PTAA/MoO3/Au/ZnO nanoparticles (ZnO NPs) interconnecting layer (ICL) D18:Y6 layer, and MoO3/Ag layer can be seen clearly in the cross section scanning electron microscopy (SEM) image of the tandem cell (Fig. 1(c) The thicknesses for CsPbI2Br layer and D18:Y6 layer are 260 and 120 nm, respectively. The thin Au layer (1 nm) between the two subcells is important for reducing the charge transport barrier, thus improving device performance[5] The charge transport layers form a", "author_names": [ "Zuo Xiao", "Chuantian Zuo", "Liming Ding" ], "corpus_id": 233929859, "doc_id": "233929859", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Inorganic perovskite/organic tandem solar cells with efficiency over 20%", "venue": "", "year": 2021 }, { "abstract": "The paucity of near infrared (NIR) organic materials with high absorption at long wavelengths, combined with large diffusion lengths and charge mobilities, is an impediment to progress in achieving high efficiency organic tandem solar cells. Here a subcell is employed within a series tandem stack that comprises a solution processed ternary blend of two NIR absorbing nonfullerene acceptors and a polymer donor combined with a small molecular weight, short wavelength fullerene based subcell grown by vacuum thermal evaporation. The ternary cell achieves a power conversion efficiency of 12.6 0.3% with a short circuit current of 25.5 0.3 mA cm 2 an open circuit voltage of 0.69 0.01 V, and a fill factor of 0.71 0.01 under 1 sun, AM 1.5G spectral illumination. The success of this device is a result of the nearly identical offset energies between the lowest unoccupied molecular orbitals (LUMOs) of the donors with the highest occupied molecular orbital (HOMO) of the acceptor, resulting in a high open circuit voltage. A tandem structure with an antireflection coating combining these subcells demonstrates a power conversion efficiency of 15.4 0.3%", "author_names": [ "Yongxi Li", "Jiu-Dong Lin", "Xiao Liu", "Yue Qu", "Fu-Peng Wu", "Feng Liu", "Zuo-Quan Jiang", "Stephen R Forrest" ], "corpus_id": 52896399, "doc_id": "52896399", "n_citations": 45, "n_key_citations": 0, "score": 0, "title": "Near Infrared Ternary Tandem Solar Cells.", "venue": "Advanced materials", "year": 2018 }, { "abstract": "Abstract Organic tandem solar cells were investigated using modeling and simulation methods to determine the optimal structural design and to predict device efficiencies. Each tandem structure comprised two subcells composed of varying combinations of low and high bandgap donor polymers and acceptor fullerene materials. The subcell employing the low bandgap polymer, poly[2,6 (4,4 bis (2 ethylhexyl) 4H cyclopenta[2,1 b;3,4 b']dithiophene) alt 4,7 (2,1,3 benzothiadiazole) (PCPDTBT) was combined with either C 61 or C 71 based acceptor fullerene [6,6] phenyl C 61/71 butyric acid methyl ester PC 61/71 BM) Similarly, a subcell employing the high bandgap polymer, poly(3 hexylthiophene) (P3HT) was modeled after including either PC 61 BM or PC 71 BM components. The mutual effects of both subcells in tandem were analyzed to determine such parameters as current density, open circuit voltage, fill factor, and power conversion efficiency. Our results indicate that appropriate spatial ordering of the subcells can allow achievement of device efficiencies exceeding 9%", "author_names": [ "Patrick M Boland", "Keejoo Lee", "James Dean", "Gon Namkoong" ], "corpus_id": 96987016, "doc_id": "96987016", "n_citations": 23, "n_key_citations": 0, "score": 0, "title": "Design of organic tandem solar cells using low and high bandgap polymer:fullerene composites", "venue": "", "year": 2010 }, { "abstract": "The emerging field of stacked layers (double and even multi layers) in organic photovoltaic cells is reviewed. Owing to the limited absorption width of organic molecules and polymers, only a small fraction of the solar flux can be harvested by a single layer bulk heterojunction photovoltaic cell. Furthermore, the low charge carrier mobilities of most organic materials limit the thickness of the active layer. Consequently, only part of the intensity of the incident light at the absorption maximum is absorbed. A tandem or multi junction solar cell, consisting of multiple layers each with their specific absorption maximum and width, can overcome these limitations and can cover a larger part of the solar flux. In addition, tandem or multi junction solar cells offer the distinct advantage that photon energy is used more efficiently, because the voltage at which charges are collected in each subcell is closer to the energy of the photons absorbed in that cell. Recent developments in both small molecule and polymeric photovoltaic cells are discussed, and examples of photovoltaic architectures, geometries, and materials combinations that result in tandem and multi junction solar cells are presented.", "author_names": [ "Afshin Hadipour", "Bert de Boer", "Paul W M Blom" ], "corpus_id": 56380045, "doc_id": "56380045", "n_citations": 229, "n_key_citations": 1, "score": 0, "title": "Organic tandem and multi junction solar cells", "venue": "", "year": 2008 } ]
TAG Crystal growth
[ { "abstract": "Recent progress in the development of organic semiconductor materials has improved the performance of both p and n type transistors. Currently, it is anticipated that the next step in the evolution of electronics will be to establish a reliable fabrication technique for integrated electronic devices such as plastic sensor films and radio frequency identification (RFID) tags. Herein, a new fabrication process to grow line shaped organic single crystalline films with widths on the order of one mm is reported. To realize large scale complementary logic circuits, it is necessary to precisely control the growth conditions of p type and n type semiconductors when painting on different areas on the same substrate. This method makes it possible to fabricate highly oriented organic thin films elongated over a few millimeters for both p and n type semiconductors next to one another. The p type and n type semiconductor crystals grown by this technique exhibit excellent average mobilities of 4.9 cm2 V 1 s 1 and 0.16 cm2 V 1 s 1 respectively. A prototypical RFID tag based on single crystals fabricated with the presented technique is also demonstrated. This tag was able to transfer 4 bit digital signals including the information from a temperature sensor through near field wireless communication at the commercially usable frequency of 13.56 MHz.", "author_names": [ "Akifumi Yamamura", "Hiroyuki Matsui", "Mayumi Uno", "Nobuaki Isahaya", "Yuki Tanaka", "Makoto Kudo", "Masataka Ito", "Chikahiko Mitsui", "Toshihiro Okamoto", "Jun Takeya" ], "corpus_id": 114115135, "doc_id": "114115135", "n_citations": 31, "n_key_citations": 0, "score": 0, "title": "Painting Integrated Complementary Logic Circuits for Single Crystal Organic Transistors: A Demonstration of a Digital Wireless Communication Sensing Tag", "venue": "", "year": 2017 }, { "abstract": "Vis NIR magneto optical crystals are the key materials in the fields of optical fiber communication, smart grids, optical fiber lasers, and so on. In this paper, the incongruent melting Tb3Al5O12 (TAG) single crystals with centimeter size and high quality were grown rapidly by an EFG method with the suitable design of a melt component. The effects of the sintering temperature of polycrystalline materials, the melt component, and the growth rate on the crystal quality were discussed in detail. The Verdet constants, hardness, thermal expansion coefficients, specific heat capacities, and thermal diffusivities of TAG crystal were measured. The results show that the Verdet constant of the TAG crystal is 8 30% larger than those of Tb3Sc2Al3O12 (TSAG) and Tb3Ga5O12 (TGG) crystals. Additionally, the TAG crystal also has the advantage in both thermal conductivity and hardness. Therefore, the TAG crystal has good comprehensive performance and thus has important application prospects.", "author_names": [ "Haipeng Liu", "Guang Zhan", "Gonghui Wu", "Caigen Song", "Xuan Wu", "Qianrui Xu", "Xin Chen", "Xiaoling Hu", "Naifeng Zhuang", "Jianzhong Chen" ], "corpus_id": 104362793, "doc_id": "104362793", "n_citations": 5, "n_key_citations": 0, "score": 1, "title": "Improved Edge Defined Film Fed Growth of Incongruent Melting Tb3Al5O12 Crystal with High Magneto Optical and Thermal Performances", "venue": "", "year": 2019 }, { "abstract": "The aim of the present study was to obtain the crystal of transcription factor LytR of streptococcus pneumoniae for X ray crystal structure and function analysis. The LytR gene of D39 strains from Streptococcus pneumoniae (S. pn) was cloned into the prokaryotic expression vector pET32a( then overexpression was obtained in the E. coli BL21 (DE3) through transformation of the recombinant plasmid that had been verified by colony PCR and sequencing. Soluble fusion protein with His tag highly expressed by the induction of 0.5 mmol/L IPTG and was purified by a three step procedure, the purity of the purified LytR recombinant protein was over 90% Preliminary screening of crystallization conditions was performed using the hanging drop vapour diffusing method with Hampton Crystal screen and PEG screen kits. The protein crystals X ray diffraction data were collected from a single crystal and more stick crystals whose X ray diffraction reached 4.0 A were obtained. These works laid the foundation for further research on the 3D structure of putative transcription factor LytR and its biological aspects.", "author_names": [ "Xun Min", "Wen Zhong", "Shasha Zhao", "Jie Dong", "Shanshan Dong", "Aie Zhou", "Wenjuan Yan", "Deqiang Wang" ], "corpus_id": 40287984, "doc_id": "40287984", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "[Studies on expression, purification, crystal growth and optimization of putative transcription factor LytR from Streptococcus pneumoniae]", "venue": "Sheng wu yi xue gong cheng xue za zhi Journal of biomedical engineering Shengwu yixue gongchengxue zazhi", "year": 2013 }, { "abstract": "The film thickness dependence of crystal growth is investigated for isotactic polystyrene (it PS) in thin films for thicknesses from 20 down to 4 nm. The single crystals of it PS grown at 180degC in the ultrathin films show a morphology typical of diffusion controlled growth: dense branching morphology and fractal seaweed. The characteristic length of the morphology, i.e. the width of the branch, increases with decreasing film thickness. The thickness dependence of the crystal growth rate shows a crossover around the lamellar thickness of 8 nm. The thickness dependences of the growth rate and morphology are discussed in terms of the diffusion of chain molecules in thin films.", "author_names": [ "Ken Taguchi", "Hideki Miyaji", "Kunihide Izumi", "Akitaka Hoshino", "Yoshihisa Miyamoto", "Ryohei Kokawa" ], "corpus_id": 13052724, "doc_id": "13052724", "n_citations": 44, "n_key_citations": 1, "score": 0, "title": "CRYSTAL GROWTH OF ISOTACTIC POLYSTYRENE IN ULTRATHIN FILMS: FILM THICKNESS DEPENDENCE", "venue": "", "year": 2001 }, { "abstract": "Purification of triglycerides from fully hydrogenated palm kernel oil (FHPKO) and fully hydrogenated coconut oil (FHCNO) was performed by a chromatographic method. Lipid composition, thermal properties, polymorphism, isothermal crystallization behaviour, nanostructure and microstructure of FHPKO, FHPKO triacylglycerol (TAG) FHCNO and FHCNO TAG were evaluated. Removal of minor components had no effect on triglycerides composition. However, the presence of the minor components did increase the slip melting point and promote onset of crystallization. Furthermore, the thickness of the nanoscale crystals increased, and polymorphic transformation from b' to b occurred in FHPKO after the removal of minor components, and from a to b' in FHCNO. Sharp changes in the values of the Avrami constant K and exponent n suggested that the presence of minor components changed the crystal growth mechanism. The PLM results indicated that a coarser crystal structure with lower fractal dimension appeared after the removal of minor components from both FHPKO and FHCNO.", "author_names": [ "Xiuhang Chai", "Zong Meng", "Peirang Cao", "Xin-Yu Liang", "Michael Piatko", "Shawn Campbell", "Seong Koon Lo", "Yuanfa Liu" ], "corpus_id": 4245452, "doc_id": "4245452", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "Influence of indigenous minor components on fat crystal network of fully hydrogenated palm kernel oil and fully hydrogenated coconut oil.", "venue": "Food chemistry", "year": 2018 }, { "abstract": "PKO and CNO are composed of 97 98% triacylglycerols and 2 3% minor non triglyceride components (FFA, DAG and MAG) Triglycerides were separated from minor components by chromatographic method. The lipid composition, thermal properties, polymorphism, isothermal crystallization behavior, nanostructure and microstructure of PKO, PKO TAG, CNO and CNO TAG were evaluated. Removal of minor components had no effect on lipid composition and equilibrium solid fat contents. However, presence of minor components did increase the slip melting point and promoted the onset of crystallization from DSC crystallization profiles. The thickness of the nanoscale crystals increased with no polymorphic transformation after removing the minor components. Crystallization kinetics revealed that minor components decreased crystal growth rate with higher t1/2. Sharp changes in the values of the Avrami constant k and exponent n were observed for all fats around 10degC. Increases in n around 10degC indicated a change from one dimensional to multi dimensional growth. From the results of polarized light micrographs, the transformation from the coarser crystal structure to tiny crystal structure occurred in microstructure networks at the action of minor components.", "author_names": [ "Xiuhang Chai", "Zong Meng", "Jiang Jiang", "Peirang Cao", "Xinyu Liang", "Michael Piatko", "Shawn Campbell", "Seong Koon Lo", "Yuanfa Liu" ], "corpus_id": 46761445, "doc_id": "46761445", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Non triglyceride components modulate the fat crystal network of palm kernel oil and coconut oil.", "venue": "Food research international", "year": 2018 }, { "abstract": "Abstract Highly transparent Zr:TAG (Zr:Tb3Al5O12) ceramics were obtained by the solid state reaction after vacuum sintering (up to 82.04% at 1064 nm) Laser induced damage threshold of Zr:TAG ceramics were measured and compared to TGG (Tb3Ga5O12) crystal and ceramic. Improved optical quality and exaggerated grain growth of TAG ceramics were observed at the same time due to ZrO2 doping, which is argued to be related to the valence change of Zr4+ Zr3+ at high temperature. A detailed analysis of possible mechanisms was presented and discussed.", "author_names": [ "Jianhong Chen", "Hui Lin", "Deming Hao", "Yanru Tang", "Xuezhuan Yi", "Yuan'an Zhao", "Shengming Zhou" ], "corpus_id": 139490994, "doc_id": "139490994", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Exaggerated grain growth caused by ZrO2 doping and its effect on the optical properties of Tb3Al5O12 ceramics", "venue": "Scripta Materialia", "year": 2019 }, { "abstract": "Crystallization of triacylglycerols (TAGs) is studied in emulsion by time resolved synchrotron X ray diffraction as a function of temperature (XRDT) coupled with DSC on a single sample consisting of an emulsion of palm oil dispersed in water. This oil in water emulsion (20% palm oil) stabilized by food grade sodium caseinate and by propylene glycol monostearate (PGMS) a food emulsifier, is used as a model for the study of the influence of emulsifiers on both TAG polymorphism and nucleation. Thermal and structural evolutions of this TAG mixture are monitored by a XRDT/DSC technique within the droplets during its crystallization and subsequent melting. In the specific conditions used and thanks to the high flux of synchrotron light, we demonstrate that both crystallization and polymorphism of a fat mixture are influenced by the presence of PGMS. The technique is sensitive enough to detect variations induced by the presence of emulsifier amounts ranging between 0 and 0.2% Despite the low amount added, the.", "author_names": [ "Daniel J E Kalnin", "Olivier Schafer", "Heinz Amenitsch", "Michel Ollivon" ], "corpus_id": 95093806, "doc_id": "95093806", "n_citations": 37, "n_key_citations": 2, "score": 0, "title": "Fat crystallization in emulsion: Influence of emulsifier concentration on triacylglycerol crystal growth and polymorphism", "venue": "", "year": 2004 }, { "abstract": "A growing attachment: Porous coordination polymer (PCP) nanorods are synthesized by modulation of the coordination equilibria between framework components, which regulates the rate of framework extension and crystal growth. Investigation of the crystal growth mechanism by TEM indicates that face selective modulation on the surfaces of PCP crystals enhances the anisotropic crystal growth of nanorods by an oriented attachment mechanism.", "author_names": [ "Takaaki Tsuruoka", "Shuhei Furukawa", "Yohei Takashima", "Kaname Yoshida", "Seiji Isoda", "Susumu Kitagawa" ], "corpus_id": 585481, "doc_id": "585481", "n_citations": 486, "n_key_citations": 4, "score": 0, "title": "Nanoporous nanorods fabricated by coordination modulation and oriented attachment growth.", "venue": "Angewandte Chemie", "year": 2009 }, { "abstract": "TAG fibers were grown by the micro pulling down method from stoichiometric and alumina rich melts. Using the Czochralski technique polycrystalline TAG samples were obtained from alumina rich melts. It was shown that both growth methods the crystallization of TAP can be avoided by starting from a melt concerning less than 32 mol Tb2O3.", "author_names": [ "Steffen Ganschow", "Boris M Epelbaum", "Detlef Klimm", "Akira Yoshikawa", "Tsuguo Fukuda" ], "corpus_id": 137454912, "doc_id": "137454912", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Terbium aluminum garnet phase diagram and crystal growth", "venue": "Other Conferences", "year": 1999 } ]
Amplitude shift keying using 555 timer
[ { "abstract": "A theoretical model for all optical modulation format conversion from amplitude shift keying (ASK) to phase shift keying (PSK) has been proposed using a reflective vertical cavity semiconductor saturable absorber (R VCSSA) The R VCSSA is a nonlinear device. The phase response of the device has been studied numerically with different input intensities. It has been observed from the simulated result that a maximum phase of p/2 with the reflected signal could be obtained by properly adjusting the input intensity. The conversion of an intensity modulated return to zero (RZ) signal to a binary phase shift keying signal has been analyzed based upon the simulated result. The pump signal is considered to be an intensity modulated RZ signal with wavelength fixed at the cavity resonance of the R VCSSA device, and a cavity detuned continuous wave source is used as a probe signal to carry out this operation. This device could be employed in all optical future networks as an all optical nonlinear signal converter for ASK to PSK conversion.", "author_names": [ "Rajib Pradhan", "Amit Choudhary", "Santu Kumar Samanta", "L Mishra", "S Jana", "Prasanta Kumar Datta" ], "corpus_id": 228910470, "doc_id": "228910470", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Modeling of all optical modulation format conversion from amplitude shift keying to phase shift keying using a vertical cavity quantum wells absorber", "venue": "", "year": 2020 }, { "abstract": "Transmission of information using ultrasonic elastic waves on existing metallic pipes provides an alternative communication option across physical barriers in a highly partitioned industrial complex, such as a nuclear facility. This work investigates the feasibility of the transmission of digital images over metallic pipes. Ultrasonic communication systems for transmission of images on a nuclear grade stainless steel pipe were assembled for bench scale demonstration. Information carriers in this system are refracted shear waves transmitted and received with piezoelectric transducers (PZTs) operating at 2 MHz nominal frequency. The refraction and propagation of ultrasonic shear waves were modeled with COMSOL software. An amplitude shift keying (ASK) communication protocol for image transmission was developed and implemented in the GNURadio software defined radio (SDR) environment. Digital information was converted to analog ultrasonic signals using Red Pitaya electronic boards. The performance of the ASK protocol is evaluated at the output of every block in the GNURadio program by monitoring the transmission of select characters. Using the ASK communication protocol, the transmission of the 32 KB image was demonstrated at 2 Kbps bitrate across 6 ft long stainless steel pipe. Preliminary evaluation of ultrasonic communication on the piping of a nuclear facility, such as signal transmission on bent pipes, was performed with COMSOL computer simulations.", "author_names": [ "Alexander Heifetz", "Dmitry Shribak", "X Huang", "B Wang", "Jafar Saniie", "J Young", "Sasan Bakhtiari", "Richard B Vilim" ], "corpus_id": 210949844, "doc_id": "210949844", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Transmission of Images With Ultrasonic Elastic Shear Waves on a Metallic Pipe Using Amplitude Shift Keying Protocol", "venue": "IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control", "year": 2020 }, { "abstract": "LED Camera Visible Light Communication (VLC) is gaining increasing attention, thanks to its readiness to be implemented with Commercial Off The Shelf devices and its potential to deliver pervasive data services indoors. Nevertheless, existing LED Camera VLC systems employ mainly low order modulations such as On Off Keying (OOK) given the simplicity of their implementation, yet such rudimentary modulations cannot yield a high throughput. In this paper, we investigate various opportunities of using a high order modulation to boost the throughput of LED Camera VLC systems, and we decide that Amplitude Shift Keying (ASK) is the most suitable scheme given the limited operating frequency of such systems. However, directly driving an LED to emit different levels of luminance may suffer heavy distortions caused by the nonlinear behavior of LED. As a result, we innovatively propose to generate ASK using the composition of light emission. In other words, we digitally control the On Off states of several groups of LED chips, so that their light emissions compose in the air to produce various ASK symbols. We build a prototype of this novel ASK based VLC system and demonstrate its superior performance over existing systems: it achieves a rate of 2 kbps at a 1 m distance with only a single LED luminaire for static users and more than 1 kbps for mobile users.", "author_names": [ "Yanbing Yang", "Jun Luo" ], "corpus_id": 86455498, "doc_id": "86455498", "n_citations": 4, "n_key_citations": 1, "score": 0, "title": "Composite Amplitude Shift Keying for Effective LED Camera VLC", "venue": "IEEE Transactions on Mobile Computing", "year": 2020 }, { "abstract": "As a method of dimming support for visible light communications using a massive LED array, we consider a hybrid pulse width modulation/digitally controlled pulse amplitude modulation (PWM/DPAM) system. Especially, in this paper, we consider a digital color shift keying (DCSK) using an RGB LED array as an optical intensity modulation scheme, that transmits data through the ratio of the optical intensities (i.e. color) emitted by red, green, and blue LEDs. In DCSK, since only one color is activated in each RGB LED at a time, the color can be represented by the combination of the digitally (i.e. linearly) controlled \"ON OFF\" LEDs. In general, for the dimming control system of DCSK, two schemes have been considered. One is the dimming control by PWM, which changes the duty cycle of optical transmit signals, and the other is the dimming control by DPAM, which changes the number of active LEDs in the RGB LED array. In this paper, PWM and DPAM are combined to realize a higher spectral efficiency than PWM and a wider dimming range than DPAM. We evaluate the error performances of the proposed system, DCSK with PWM, and DCSK with DPAM from a simulation analysis under several measured light dimming levels. The results show that DPAM should be used only for low bit rate systems because the effect of inter symbol interference (ISI) caused by the LED frequency response, increases at a high bit rate. While, PWM is significantly robust against ISI because the PWM signal duration is limited in a symbol duration at the low dimming levels and the empty duration can mitigate the effect of ISI even if the bit rate is high. When focusing on symbol error rate performances corresponding to the dimming levels, the hybrid dimming control and the PWM dimming control can achieve lower signal energy to noise ratio at the dimming level of low and high, respectively.", "author_names": [ "Jumpei Okumura", "Yusuke Kozawa", "Yohtaro Umeda", "Hiromasa Habuchi" ], "corpus_id": 349549, "doc_id": "349549", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Hybrid PWM/DPAM Dimming Control for Digital Color Shift Keying Using RGB LED Array", "venue": "IEEE Journal on Selected Areas in Communications", "year": 2018 }, { "abstract": "Radio Frequency (RF) communication is always considered as the main choice to transmit data from wireless body area network devices. However, wireless communication using RF has radiation that can pierce through skin and have negative effect for body. An ultrasonic communication can be used as an alternative to transmit the data. In this paper, we have developed an ultrasonic communication system using amplitude shift keying (ASK) modulation. The data are taken from galvanic skin response sensor and processed by a microcontroller. The processed data then modulated using ASK modulation technique before transmitted using ultrasonic transducers. The results showed that the ultrasonic transducers are able to transmit data in relatively short range and narrow beamwidth. The ASK modulation technique performed well for modulating and demodulating the signal taken from GSR sensor.", "author_names": [ "Muhammad Harry Bintang Pratama", "Arif Munandar", "Khusnil Mujib", "Erizco Satya Wicaksono", "Ajub Ajulian Zahra" ], "corpus_id": 25350351, "doc_id": "25350351", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Implementation of ultrasonic communication for wireless body area network using amplitude shift keying modulation", "venue": "2016 IEEE Region 10 Conference (TENCON)", "year": 2016 }, { "abstract": "We consider least squares estimators of carrier phase and amplitude from a noisy communications signal that contains both pilot signals, known to the receiver, and data signals, unknown to the receiver. We focus on signaling constellations that have symbols evenly distributed on the complex unit circle, i.e. M ary phase shift keying. We show, under reasonably mild conditions on the distribution of the noise, that the least squares estimator of carrier phase is strongly consistent and asymptotically normally distributed. However, the amplitude estimator is asymptotically biased and converges to a positive real number that is a function of the true carrier amplitude, the noise distribution and the size of the constellation. This appears to be the first time that the statistical properties of a non data aided estimator for carrier amplitude have been analyzed theoretically. The results of Monte Carlo simulations are provided and these agree with the theoretical results.", "author_names": [ "Robby G McKilliam", "Andre Pollok", "William G Cowley", "I Vaughan L Clarkson", "Barry G Quinn" ], "corpus_id": 14146430, "doc_id": "14146430", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Carrier Phase and Amplitude Estimation for Phase Shift Keying Using Pilots and Data", "venue": "IEEE Transactions on Signal Processing", "year": 2014 }, { "abstract": "The Phase/Amplitude shift keying modulator using digital oscillator is presented in this work. The proposed method comprises of digital line coder, digital differentiator and digital oscillator. The line coding signal is transformed into impulse signal to excite the oscillator to generate the desired PSK or ASK signal. The advantages of this technique are simple, high accuracy and robust to noise. It is robust to noise because all components are digital implementation.", "author_names": [ "Pichet Wisartpong", "R Punchalard", "A Nosan" ], "corpus_id": 14294610, "doc_id": "14294610", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Phase/amplitude shift keying using digital sinusoidal oscillator", "venue": "The 8th Electrical Engineering/ Electronics, Computer, Telecommunications and Information Technology (ECTI) Association of Thailand Conference 2011", "year": 2011 }, { "abstract": "This paper presents design on amplitude shift keying (ASK) used in 125 kHz RFID tag, which is simulated by Multisim software. In the low frequency of 125 kHz RFID system, there are generally three portions: RFID tag, RFID reader and digital processing system. Also in RFID tag, it is consisted of antenna unit and functional units of sinusoidal oscillator circuit, square wave circuit and switching circuit. Design analyses on different types of sinusoidal oscillator circuits, square wave circuit and switching circuit have been described with the simulation results to meet the requirements for RFID tag. On design analysis of sinusoidal oscillators, the certain type of oscillator has been chosen with the parameters of desired frequency and certain time period for start up oscillation. Also the desired frequency with certain duty cycle has been designed for square wave circuit. The switching circuit has been designed to generate ASK signal by modulating carrier signal of sinusoidal waveform with the square waveform of digital data.", "author_names": [ "San Hlaing Oo", "Khin Trar Trar Soe" ], "corpus_id": 145814179, "doc_id": "145814179", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Design on Amplitude Shift Keying", "venue": "", "year": 2019 }, { "abstract": "Abstract A photonic approach to generate frequency doubled microwave waveforms using an integrated dual polarization quadrature phase shift keying (DP QPSK) modulator driven by a sinusoidal radio frequency (RF) signal is proposed. By adjusting the dc bias points of the DP QPSK modulator, the obtained second order and six order harmonics are in phase while the fourth order harmonics are complementary when the orthogonal polarized outputs of the modulator are photodetected. After properly setting the modulation indices of the modulator, the amplitude of the second order harmonic is 9 times of that of the six order harmonic, indicating a frequency doubled triangular waveform is generated. If a broadband 90deg microwave phase shifter is attached after the photodetector (PD) to introduce a 90deg phase shift, a frequency doubled square waveform can be obtained after adjusting the amplitude of the second order harmonic 3 times of that of the six order harmonic. The proposal is first theoretically analyzed and then validated by simulation. Simulation results show that a 10 GHz triangular and square waveform sequences are successfully generated from a 5 GHz sinusoidal RF drive signal.", "author_names": [ "Zihang Zhu", "Shanghong Zhao", "Xuan Li", "Kun Qu", "Tao Lin" ], "corpus_id": 126033034, "doc_id": "126033034", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Frequency doubled microwave waveforms generation using a dual polarization quadrature phase shift keying modulator driven by a single frequency radio frequency signal", "venue": "", "year": 2018 }, { "abstract": "A photonic microwave frequency shift keying (FSK) signal generator is proposed and experimentally demonstrated based on an equivalent photonic switch (EPS) The EPS is constructed using a polarization multiplexing dual drive Mach Zehnder modulator (PM DMZM) By properly controlling the data sequences and RF signals applied to the PM DMZM, microwave FSK signals with flexible frequency intervals can be obtained. The proposed FSK signal generator features the advantages of a simple structure, low loss, good stability, and great frequency tunability. In addition, the proposed setup can also be easily reconfigured to generate microwave amplitude shift keying and phase shift keying signals. The experimental results show that 2 Gb/s at 5/14 GHz and 1 Gb/s at 6/20 GHz microwave FSK signals are successfully generated, after transmission over 5 km single mode fiber. The required received optical power at 7% forward error correction threshold is only 14.48 dBm.", "author_names": [ "Mingzheng Lei", "Zhennan Zheng", "Chunqi Song", "Yunping Bai", "Jinwang Qian", "Shanguo Huang", "Xinlu Gao" ], "corpus_id": 189814572, "doc_id": "189814572", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Equivalent photonic switch for microwave frequency shift keying signal generation.", "venue": "Optics letters", "year": 2019 } ]
semiconductor machine learning
[ { "abstract": "A machine learning (ML) model by combing two autoencoders and one linear regression model is proposed to avoid overfitting and to improve the accuracy of Technology Computer Aided Design (TCAD) augmented ML for semiconductor structural variation identification and inverse design, without using domain expertise. TCAD augmented ML utilizes TCAD simulations to generate sufficient data for ML model development when experimental data are inadequate. The ML model can then be used to identify semiconductor structural variation for given experimental electrical measurements. In this study, the variation of layer thicknesses in the p i n diode is used as a demonstration. An ML model is developed to predict the diode layer thicknesses based on a given Current Voltage (IV) curve. Although the variations of interest can be incorporated easily in TCAD simulations to generate ML training data, the TCAD augmented ML model generally is overfitted and cannot predict the variations in experiment well due to hidden variables which also alters the IV curves. We show that by using an autoencoder, this problem can be solved. To verify the effectiveness, another set of TCAD simulation data is generated with hidden variables (dopant concentration variation) to emulate experimental data. Testing on the second set of data shows that the proposed model can avoid overfitting and has up to 15 times improvement in accuracy in thickness prediction. Moreover, this model is used successfully to perform inverse design and can capture an underlying physics that cannot be described by a simple physical parameter.", "author_names": [ "Kashyap Mehta", "Sophia Susan Raju", "Ming Xiao", "Boyan Wang", "Yuhao Zhang", "Hiu Yung Wong" ], "corpus_id": 221159484, "doc_id": "221159484", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Improvement of TCAD Augmented Machine Learning Using Autoencoder for Semiconductor Variation Identification and Inverse Design", "venue": "IEEE Access", "year": 2020 }, { "abstract": "Abstract This present work utilizes the distortion due to the incorporation of dopants into crystal lattice structure of zinc oxide (ZnO) semiconductor to model the associated energy band gap. The proposed model hybridizes machine learning support vector regression model (MLSVRM) and gravitational search algorithm (GSA) that is based on Newtonian mechanical principle of motion. The performance of the developed hybrid gravitational search (GS) based MLSVRM is compared with stepwise regression (ST) based model and the existing ordinary support vector regression computational intelligence (SVRCI) model in the literature. The developed hybrid GS MLSVRM performs better than ST based model and the existing SVRCI model in the literature by 83.74% and 42.59% respectively using mean absolute percentage deviation (MAPD) as a performance measuring parameter. The developed hybrid GS MLSVRM further shows superior performance over the two compared models using other performance measuring parameters such as root mean square error (RMSE) mean absolute error (MAE) and correlation coefficient (CC) The superior performance of the developed hybrid model can be attributed to the power of hybridization and intrinsic ability to approximate non linear relationship between lattice distortion and energy band gap of the doped semiconductor. The precision of the developed hybrid model would ultimately hasten ZnO band gap characterization without experimental stress.", "author_names": [ "Sami M Ibn Shamsah", "Taoreed Olakunle Owolabi" ], "corpus_id": 226352978, "doc_id": "226352978", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Newtonian mechanics based hybrid machine learning method of characterizing energy band gap of doped zno semiconductor", "venue": "", "year": 2020 }, { "abstract": "Advanced data analysis tools and techniques are important for semiconductor companies to gain competitive advantage. In particular, yield prediction tools, which fully utilize production data, help to improve operational efficiency and reduce production costs. This paper introduces a novel and scalable framework for semiconductor manufacturing Final Test (FT) yield prediction leveraging machine learning techniques. This framework is able to predict FT yield at wafer fabrication stage, so that FT low yield problems can be caught at an earlier production stage compared to past studies. Our work presents a robust solution to automatically handle both numerical and categorical production related data without prior knowledge of the low yield root cause. Gaussian Mixture Models, One Hot Encoder and Label Encoder techniques are adopted for data pre processing. To improve model performance for both binary and multi class classification, model selection and model ensemble using the F1 macro method is demonstrated. The framework has been applied to three mass production products with different wafer technologies and manufacturing flows. All of them achieved high F1 macro test score indicative of the robustness of our framework.", "author_names": [ "Dan Jiang", "Weihua Lin", "Nagarajan Raghavan" ], "corpus_id": 226851711, "doc_id": "226851711", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "A Novel Framework for Semiconductor Manufacturing Final Test Yield Classification Using Machine Learning Techniques", "venue": "IEEE Access", "year": 2020 }, { "abstract": "In this article, the authors attempt to describe the core quality inspection during semiconductor manufacturing in terms of production efficiency and yield. Special focus is therefore given to photolithography, which is the most critical step for the fabrication of wafer patterns in front end processes. Further, machine learning approaches are demonstrated and their applicability in semiconductor manufacturing industry is discussed. Also, a technical concept regarding virtual metrology for advanced process control in semiconductor production is introduced as a potential utilization case. Finally, current status and future trends in technology as well as application are summarized based on authors' perspective in the concluding section.", "author_names": [ "Lei Wang" ], "corpus_id": 226239112, "doc_id": "226239112", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Application of Machine Learning for Process Control in Semiconductor Manufacturing", "venue": "", "year": 2020 }, { "abstract": "Maintenance in manufacturing has been developed and researched in the last few decades at a very rapid rate. It's a major step in process control to build a decision tool that detects defects in equipment or processes as quickly as possible to maintain high process efficiencies. However, the high complexity of machines, and the increase in data available in almost all areas, makes research on improving the accuracy of fault detection via data mining more and more challenging issue in this field. In our paper we present a new predictive model of semiconductor failures, based on machine learning approach, for predictive maintenance in industry 4.0. The framework of our model includes: Dataset and data acquisition, data preprocessing in three phases (over sampling, data cleaning, and attribute reduction with principal component analysis (PCA) technique and CfsSubsetEval technique) data modeling, evaluation model and implementation model. We used SECOM dataset to develop four different models based on four algorithms (Naive Bayesian, C4.5 Decision tree, Multilayer perceptron (MLP) Support vector machine) according to the five metrics (True Positive rate, False Positive rate, Precision, F Mesure and Accuracy) We implemented our new predictive model with 91, 95% of accuracy, as a new efficient predictive model of semiconductor failures. Keywords Machine learning; semiconductor; predictive maintenance; industry 4.0", "author_names": [ "Yousef El Mourabit", "Youssef El", "Hicham Zougagh", "Younes Wadiai" ], "corpus_id": 231895475, "doc_id": "231895475", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Predictive System of Semiconductor Failures based on Machine Learning Approach", "venue": "", "year": 2020 }, { "abstract": "While spin qubits based on gate defined quantum dots have demonstrated very favorable properties for quantum computing, one remaining hurdle is the need to tune each of them into a good operating regime by adjusting the voltages applied to electrostatic gates. The automation of these tuning procedures is a necessary requirement for the operation of a quantum processor based on gate defined quantum dots, which is yet to be fully addressed. We present an algorithm for the automated fine tuning of quantum dots, and demonstrate its performance on a semiconductor singlet triplet qubit in GaAs. The algorithm employs a Kalman filter based on Bayesian statistics to estimate the gradients of the target parameters as function of gate voltages, thus learning the system response. The algorithm's design is focused on the reduction of the number of required measurements. We experimentally demonstrate the ability to change the operation regime of the qubit within 3 to 5 iterations, corresponding to 10 to 15 minutes of lab time.", "author_names": [ "Julian D Teske", "Simon Sebastian Humpohl", "Ren'e Otten", "Patrick Bethke", "Pascal Cerfontaine", "Jonas Dedden", "Arne Ludwig", "Andreas Dirk Wieck", "Hendrik Bluhm" ], "corpus_id": 117683624, "doc_id": "117683624", "n_citations": 28, "n_key_citations": 1, "score": 0, "title": "A machine learning approach for automated fine tuning of semiconductor spin qubits", "venue": "Applied Physics Letters", "year": 2019 }, { "abstract": "In this paper, we show the possibility of using Technology Computer Aided Design (TCAD) to assist machine learning for semiconductor device failure trouble shooting and device reverse engineering. When TCAD simulation models and parameters are properly chosen and calibrated, large number of devices with random defects and structural characteristics can be generated and simulated. The results can then be used to train machine learning algorithms to predict the defect and structural characteristics of a device with given electrical characteristics (such as IV's and CV's) 1D PIN diode with various layer thicknesses and doping concentrations are used in this study. It is showed that with less than 2000 training samples, by using simple linear regression, one can achieve good prediction of layer thickness and doping of a given IV curve.", "author_names": [ "Y S Bankapalli", "Hiu Yung Wong" ], "corpus_id": 204820625, "doc_id": "204820625", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "TCAD Augmented Machine Learning for Semiconductor Device Failure Troubleshooting and Reverse Engineering", "venue": "2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD)", "year": 2019 }, { "abstract": "Semiconductor cluster equipment adds an integral component to the modern semiconductor manufacturing process. These complex tools provide a flexible deployment option to group multiple processing steps into a single piece of equipment, allowing for more efficient processing. They also contribute to a reduction in the number of times a wafer must go through the atmospheric vacuum atmospheric cycle. Such highly automated tools present a complex scheduling challenge where process specific requirements are balanced against a need to achieve maximum wafer throughput in a fault tolerant manner. Software engineers typically build schedulers using a set of manually configured heuristics but this can be a labor intensive process where small changes to the cluster configuration or process requirements can require large changes to the scheduler. Our motivation for this work was to investigate whether a machine learning approach to complex cluster scheduling could be developed more efficiently and at a lower cost than existing methods.", "author_names": [ "Doug Suerich", "Terry Young" ], "corpus_id": 199509662, "doc_id": "199509662", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Machine Learning for Optimized Scheduling in Complex Semiconductor Equipment", "venue": "2019 30th Annual SEMI Advanced Semiconductor Manufacturing Conference (ASMC)", "year": 2019 }, { "abstract": "Abstract The progress of digitalization enables new potentials to supply chain management by available data as well as by analysis methods like machine learning. This paper focuses on the master production planning matching demand and supply for a midterm time horizon, in a volatile, diverse and capacity constrained environment. Therefore, a framework for measuring instability is outlined, a machine learning approach to predict instability is developed and applied using the CRISP DM methodology on real data of a semiconductor manufacturer. The evaluation and results foster the concept and the field of application, but request the next step of prescriptive instability minimization.", "author_names": [ "Tim Lauer", "Sarah Legner", "Michael Henke" ], "corpus_id": 213671070, "doc_id": "213671070", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Application of machine learning on plan instability in master production planning of a semiconductor supply chain", "venue": "", "year": 2019 }, { "abstract": "In this work, we present a unique approach of combining TCAD modelling and machine learning to detect the defect locations of a bridging defect in a single fin FinFET. The prediction of the defect location is guided by the predictive model consisting of Random Forest algorithm which is trained with the measureable electrical attributes from the I V. High accuracy in predicting the defect location is achieved by the proposed scheme which can further enhance the FA success rate, expediting the cycle of design to product.", "author_names": [ "C W Teo", "Kain Lu Low", "Vinod Narang", "Aaron Voon-Yew Thean" ], "corpus_id": 204820227, "doc_id": "204820227", "n_citations": 8, "n_key_citations": 1, "score": 0, "title": "TCAD Enabled Machine Learning Defect Prediction to Accelerate Advanced Semiconductor Device Failure Analysis", "venue": "2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD)", "year": 2019 } ]
neural network clock time rhythm
[ { "abstract": "This article presents the development and implementation of an artificial neural network (ANN) and a support vector machine (SVM) on a 32 bit ARM R Cortex R M4 microcontroller core from Freescale Semiconductor and on a FPGA Spartan R 6 from XilinxTM looking for real time detection of ventricular tachycardia (VT) and ventricular fibrillation (VF) They were compared in terms of accuracy and computational cost. A Fast Wavelet Transform (FWT) was used, and the energy in each sub band frequency was calculated in the feature extraction stage. For the training and validation algorithms, labeled signals from MIT BIH database with normal sinus rhythm, VF and VT in a time window of 2 seconds were used. Test results achieve an accuracy of 99.46% for both ANN and SVM with execution time less than 0.6 ms in microcontroller and 30 ms in FPGA for ANN and less than 30 ms in a microcontroller for SVM. The test was done with a 32 MHz clock.", "author_names": [ "Andres Orozco-Duque", "Santiago Rua", "Santiago Zuluaga", "Alfredo Redondo", "J Restrepo", "John Bustamante" ], "corpus_id": 30918637, "doc_id": "30918637", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Support Vector Machine and Artificial Neural Network Implementation in Embedded Systems for Real Time Arrhythmias Detection", "venue": "BIOSIGNALS", "year": 2013 }, { "abstract": "The subjective representation of \"time\" is critical for cognitive tasks but also for several motor activities. The neural network supporting motor timing comprises: lateral cerebellum, basal ganglia, sensorimotor and prefrontal cortical areas. Basal ganglia and associated cortical areas act as a hypothetical \"internal clock\" that beats the rhythm when the movement is internally generated. When timing information is processed to make predictions on the outcome of a subjective or externally perceived motor act, cerebellar processing and outflow pathways appear to be primarily involved. Clinical and experimental evidence on time processing and motor control points to a dysfunction of the neural networks involving basal ganglia and cerebellum in movement disorders. In some cases, temporal processing deficits could directly contribute to core motor features of the movement disorder, as in the case of bradykinesia in Parkinson's disease. For other movement disorders, the relationship between abnormal time processing and motor performance is less obvious and requires further investigation, as in the reduced accuracy in predicting the temporal outcome of a motor act in dystonia. We aim to review the literature on time processing and motor control in Parkinson's disease, dystonia, Huntington's disease, and Tourette syndrome, integrating the available findings with current pathophysiological models; we will highlight the areas in which future explorations are warranted, as well as the aspects of time processing in motor control that present translational aspects in future rehabilitation strategies. The subjective representation of \"time\" is critical for cognitive tasks but also for motor activities. Recently, greater attention has been devoted to improve our understanding of how temporal information becomes integrated within the mechanisms of motor control. Experimental evidence recognizes time processing in motor control as a complex neural function supported by diffuse cerebral networks including cortical areas, cerebellum, and other subcortical structures (Ivry and Spencer, 2004; Coull and Nobre, 2008) Timing is an essential component of motor control primarily within two types of motor tasks: (i) when producing sequential rhythmic movements or sustained movements of a definite duration (explicit timing) (ii) when the temporal information is used implicitly, such as when coordinating our movements to those of moving objects or individuals within the external environment (implicit timing) In this review, we will provide a brief description of the neural network supporting motor timing focusing only on instrumental information to explain the link between timing and motor control in movement disorders. Then we will review available data on motor timing in Parkinson's disease, dystonia, Huntington's disease, and Tourette syndrome, and discuss how this body of evidence integrates with the available information on the pathophysiology of these movement disorders. Finally, we will discuss the translational aspects of the explored neural mechanisms with respect to future rehabilitation strategies.", "author_names": [ "Laura Avanzino", "Elisa Pelosin", "Carmelo M Vicario", "Giovanna Lagravinese", "Giovanni Abbruzzese", "Davide Martino" ], "corpus_id": 7405967, "doc_id": "7405967", "n_citations": 39, "n_key_citations": 1, "score": 0, "title": "Time Processing and Motor Control in Movement Disorders", "venue": "Front. Hum. Neurosci.", "year": 2016 }, { "abstract": "The circadian clock nucleus of the mammalian brain is composed of thousands of oscillator neurons, each driven by the cell autonomous action of a defined set of circadian clock genes. A critical question is how these individual oscillators are organized into an internal clock that times behavior and physiology. We examined the neural organization of the suprachiasmatic nucleus (SCN) through time lapse imaging of a short half life green fluorescent protein (GFP) reporter of the circadian clock gene Period 1 (Per1) Using brain slice preparations, Per1 promoter rhythms were resolved at the level of the SCN, and in individual neurons within the SCN, to determine the temporal patterns of rhythmicity resulting from exposure of mice to light/dark cycle (LD) and constant darkness (DD) conditions. Quantitative imaging and patch clamp electrophysiology were used to define the relationship of Per1 gene expression to neurophysiological output on an individual neuron basis. We found that in both LD and DD, the overall rhythm of the clock nucleus is composed of individual cellular rhythms that peak in distinct phase groups at 3 4 hr intervals. However, the phase relationships of Per1 oscillations to locomotor activity and the phase relationships among individual neuronal oscillators within the SCN are different in LD and DD. There was a positive, linear correlation of Per1 transcription with neuronal spike frequency output, thus Per1::GFP rhythms are representative of physiological rhythmicity. Our results reveal multiple phase groupings of SCN oscillators and suggest that light regulation of oscillator interactions within the SCN underlies entrainment to the photoperiod.", "author_names": [ "Jorge E Quintero", "Sandra J Kuhlman", "Douglas G McMahon" ], "corpus_id": 15461614, "doc_id": "15461614", "n_citations": 269, "n_key_citations": 16, "score": 0, "title": "The Biological Clock Nucleus: A Multiphasic Oscillator Network Regulated by Light", "venue": "The Journal of Neuroscience", "year": 2003 }, { "abstract": "Circadian neural circuits generate near 24 hr physiological rhythms that can be entrained by light to coordinate animal physiology with daily solar cycles. To examine how a circadian circuit reorganizes its activity in response to light, we imaged period (per) clock gene cycling for up to 6 days at single neuron resolution in whole brain explant cultures prepared from per luciferase transgenic flies. We compared cultures subjected to a phase advancing light pulse (LP) to cultures maintained in darkness (DD) In DD, individual neuronal oscillators in all circadian subgroups are initially well synchronized but then show monotonic decrease in oscillator rhythm amplitude and synchrony with time. The small ventral lateral neurons (s LNvs) and dorsal lateral neurons (LNds) exhibit this decrease at a slower relative rate. In contrast, the LP evokes a rapid loss of oscillator synchrony between and within most circadian neuronal subgroups, followed by gradual phase retuning of whole circuit oscillator synchrony. The LNds maintain high rhythmic amplitude and synchrony following the LP along with the most rapid coherent phase advance. Immunocytochemical analysis of PER shows that these dynamics in DD and LP are recapitulated in vivo. Anatomically distinct circadian neuronal subgroups vary in their response to the LP, showing differences in the degree and kinetics of their loss, recovery and/or strengthening of synchrony, and rhythmicity. Transient desynchrony appears to be an integral feature of light response of the Drosophila multicellular circadian clock. Individual oscillators in different neuronal subgroups of the circadian circuit show distinct kinetic signatures of light response and phase retuning.", "author_names": [ "Logan Roberts", "Tanya L Leise", "Takako Noguchi", "Alexis M Galschiodt", "Jerry H Houl", "David K Welsh", "Todd C Holmes" ], "corpus_id": 11700312, "doc_id": "11700312", "n_citations": 49, "n_key_citations": 5, "score": 0, "title": "Light Evokes Rapid Circadian Network Oscillator Desynchrony Followed by Gradual Phase Retuning of Synchrony", "venue": "Current Biology", "year": 2015 }, { "abstract": "We here propose a neural network model to explore how neural oscillations might regulate the replay of memory traces. We simulate the encoding and retrieval of a series of events, where temporal sequences are uniquely identifiable by analysing population activity, as several recent EEG/MEG studies have shown. Our model comprises three parts, each considering distinct hypotheses. A cortical region actively represents sequences through the disruption of an intrinsically generated alpha rhythm, where a desynchronisation marks information rich operations as the literature predicts. A binding region converts each event into a discrete index, enabling repetitions through a sparse encoding of events. We also instantiate a temporal region, where an oscillatory \"ticking clock\" made up of hierarchical synfire chains discretely indexes a moment in time. By encoding the absolute timing between events, we show how one can use cortical desynchronisations to dynamically detect unique temporal signatures as they are replayed in the brain.", "author_names": [ "George Parish", "Sebastian Michelmann", "Simon Hanslmayr", "Howard Bowman" ], "corpus_id": 213901002, "doc_id": "213901002", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Modelling the Replay of Dynamic Memories from Cortical Alpha Oscillations with the Sync Fire deSync Model", "venue": "", "year": 2020 }, { "abstract": "The cell distribution and immunoreactivity (ir) against period (PER) pigment dispersing factor (PDF) and corazonin (CRZ) were compared between adults and nymphs in the central nervous system of the German cockroach. Although PER ir cells in the optic lobes (OL) were expressed in the nymphs from the first instar, the links between major clock cells became more elaborated after second/third instar. A circadian rhythm of locomotion was initiated at the fourth/fifth instar. The results suggest that the clock was running from hatching, but the control network needed more time to develop. In addition, the putative downstream regulators, PDF ir and CRZ ir, are co localized in various regions of the brain, indicating potential output routes of the circadian clock. CRZ ir cells with typical morphology of neurosecretory cells in the dorsolateral protocerebrum send out three neural fibers to reach the ipsilateral corpora cardiaca (CC) the antennal lobe and two hemispheres of the protocerebrum. Based on co localization with some PER ir/PDF ir cells, the CRZ ir cells have the potential to serve as a bridge between circadian neural signals and endocrine regulation. Based on PDF's role in the regulation of locomotion, our results support the finding that the locomotor circadian rhythm is possibly controlled by a hormonal route.", "author_names": [ "Yung-Yu Yang", "Chih-Jen Wen", "Archana Mishra", "Chi-Wei Tsai", "How-Jing Lee" ], "corpus_id": 39341408, "doc_id": "39341408", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Development of the circadian clock in the German cockroach, Blattella germanica.", "venue": "Journal of insect physiology", "year": 2009 }, { "abstract": "The circadian rhythm of body temperature (T(b) is a well known phenomenon. However, it is unknown how the circadian system including the suprachiasmatic nucleus (SCN) and clock genes affects thermoregulation. Food deprivation in mice induces a greater reduction of T(b) particularly in the light phase. We examined the role of Clock, one of key clock genes and the SCN during induced hypothermia. At 20 degrees C with fasting, mice increased their metabolic heat production in the dark phase and maintained T(b) whereas in the light phase, heat production was less, resulting in hypothermia. Under these conditions, neuronal activity in the SCN, assessed by cFos expression, increased only in the light phase. However, such differences in thermoregulatory and neural responses between the phases in Clock mutant mice were less marked. The neural network between the SCN and paraventricular nucleus appeared to be important in hypothermia. These findings suggest that the circadian system per se is influenced by both the feeding condition and environmental temperature and that it modulates thermoregulation.", "author_names": [ "Ken Tokizawa", "Yuki Uchida", "Kei Nagashima" ], "corpus_id": 207246725, "doc_id": "207246725", "n_citations": 22, "n_key_citations": 2, "score": 0, "title": "Thermoregulation in the cold changes depending on the time of day and feeding condition: physiological and anatomical analyses of involved circadian mechanisms", "venue": "Neuroscience", "year": 2009 }, { "abstract": "In development, morphogenetic processes are strictly coordinated in time. Cells in a developing tissue would need mechanisms for time keeping. One such time keeping mechanism is to use oscillations of gene expression. Oscillatory gene expression can be generated by transcriptional/translational feedback loops, usually referred to as a genetic oscillator. In this review article, we discuss genetic oscillators in the presence of developmental processes such as cell division, cell movement and cell differentiation. We first introduce the gene regulatory network for generating a rhythm of gene expression. We then discuss how developmental processes influence genetic oscillators. Examples include vertebrate somitogenesis and neural progenitor cell differentiation, as well as the circadian clock for comparison. To understand the behaviors of genetic oscillators in development, it is necessary to consider both gene expression dynamics and cellular behaviors simultaneously. Theoretical modeling combined with live imaging at single cell resolution will be a powerful tool to analyze genetic oscillators in development.", "author_names": [ "Koichiro Uriu" ], "corpus_id": 27482717, "doc_id": "27482717", "n_citations": 27, "n_key_citations": 0, "score": 0, "title": "Genetic oscillators in development", "venue": "Development, growth differentiation", "year": 2016 }, { "abstract": "Artificial neural networks built from two state neurons are powerful computational substrates, whose computational ability is well understood by analogy with statistical mechanics. In this work, we introduce similar analogies in the context of spiking neurons in a fixed time window, where excitatory and inhibitory inputs drawn from a Poisson distribution play the role of temperature. For single neurons with a \"bandgap\" between their inputs and the spike threshold, this temperature allows for stochastic spiking. By imposing a global inhibitory rhythm over the fixed time windows, we connect neurons into a network that exhibits synchronous, clock like updating akin to neural networks. We implement a single layer Boltzmann machine without learning to demonstrate our model.", "author_names": [ "Paul Merolla", "Tristan Ursell", "John V Arthur" ], "corpus_id": 10373975, "doc_id": "10373975", "n_citations": 14, "n_key_citations": 1, "score": 0, "title": "The thermodynamic temperature of a rhythmic spiking network", "venue": "ArXiv", "year": 2010 }, { "abstract": "The circadian rhythm of body temperature (Tb) is a well known phenomenon. However, it is unknown how the circadian system affects thermoregulation. Food deprivation in mice induces a greater reduction of Tb particularly in the light phase. We examined the role of the clock gene and the suprachiasmatic nucleus (SCN) during induced hypothermia. At 20C with fasting, mice increased their metabolic heat production in the dark phase and maintained T~b~ whereas in the light phase, heat production was less, resulting in hypothermia. Under these conditions, neuronal activity in the SCN, assessed by cFos expression, increased only in the light phase. The differences between the phases in Clock mutant mice were less marked. The neural network between the SCN and paraventricular nucleus appeared to be important in hypothermia. These findings suggest that the circadian system per se is influenced by both the feeding condition and environmental temperature and that it modulates thermoregulation.", "author_names": [ "Kei Nagashima", "Ken Tokizawa", "Yuki Uchida" ], "corpus_id": 15466583, "doc_id": "15466583", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The circadian system alters thermoregulation depending on the time of day and feeding condition", "venue": "", "year": 2009 } ]
site-controlled quantum dot atomic force microscope
[ { "abstract": "An atomic force microscope assisted technique is developed to control the position and size of self assembled semiconductor quantum dots (QDs) Presently, the site precision is as good as 1.5 nm and the size fluctuation is within 5% with the minimum controllable lateral diameter of 20 nm. With the ability of producing tightly packed and differently sized QDs, sophisticated QD arrays can be controllably fabricated for the application in quantum computing. The optical quality of such site controlled QDs is found comparable to some conventionally self assembled semiconductor QDs. The single dot photoluminescence of site controlled InAs/InP QDs is studied in detail, presenting the prospect to utilize them in quantum communication as precisely controlled single photon emitters working at telecommunication bands.", "author_names": [ "H -Z Song", "Tatsuya Usuki", "Toshio Ohshima", "Yoshiki Sakuma", "Mitsuo Kawabe", "Yositaka Okada", "Kazuya Takemoto", "Toshiyuki Miyazawa", "Shinichi Hirose", "Yoshiaki Nakata", "Motomu Takatsu", "Naoki Yokoyama" ], "corpus_id": 6736912, "doc_id": "6736912", "n_citations": 19, "n_key_citations": 1, "score": 0, "title": "Site controlled quantum dots fabricated using an atomic force microscope assisted technique", "venue": "Nanoscale Research Letters", "year": 2006 }, { "abstract": "In this project, we combine Ga+ focused ion beam (FIB) patterning and self assembly of InGaAs quantum dots in order to produce regular quantum dot (QD) arrays. The GaAs substrate is patterned before transporting into molecular beam epitaxy growth chamber to do anneal and overgrowth. The thickness of deposited InAs is precisely controlled. Quantum dots are expected to nucleate at specific locations, where the ion beam has previously implanted gallium atoms. The properties of the quantum dots formed are related to the FIB beam parameters, which include accelerating voltage, probe current, dwell time and pitch. We studied and statistically analyzed the relationship, focusing on their diameter, height and distribution. Scanning electronic microscope (SEM) and atomic force microscope (AFM) images have been used to analyze the patterns and QDs before and after overgrowth. Micro PL study was performed to test the QD opto electronic property. Scanning transmission electron microscope (STEM) cross sectional analysis and X ray mapping is performed.", "author_names": [ "Haoyu Zhang", "Ian M Ross", "Thomas Walther" ], "corpus_id": 135811021, "doc_id": "135811021", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Study of site controlled quantum dot formation on focused ion beam patterned GaAs substrate", "venue": "", "year": 2013 }, { "abstract": "We have developed a nanoprobe assisted bottom up technique that allows to fabricate site controlled quantum dots (SC QDs) using a specially designed atomic force microscope probe, referred to as the Nano Jet Probe (NJP) Beginning with the fabrication of regular QD arrays by using the NJP, we vertically aligned self assembled InAs QDs using the strain induced stacking method and produced assembled QD stacks. In order to improve the optical property of the SC QDs, an AlGaAs barrier layer was introduced in the spacer layer of the stacked structures. The photoluminescence measurements of the fabricated structures revealed that they had good crystallographic qualities.", "author_names": [ "Shunsuke Ohkouchi", "Nobuhiko Ozaki", "Yoshimasa Sugimoto", "Hiroshi Ishikawa", "Kiyoshi Asakawa" ], "corpus_id": 95769331, "doc_id": "95769331", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Site controlled InAs quantum dot formation grown on the templates fabricated by the Nano Jet Probe method", "venue": "", "year": 2009 }, { "abstract": "In this work, surface modification of InAs wetting layer was carried out during InAs/GaAs (001) quantum dot molecular beam epitaxy growth by in situ pulsed laser (355 nm/ 10 ns) We investigated the morphology transformation of wetting layer by atomic force microscope. Atomic layer removal and formation of nano holes were observed on the sample surface. It is proposed that the material removal of wetting layer induced by electronic excitation is triggered by In atom vacancies due to the desorption at substrate temperature of 480degC. The effects of surface modification on QD growth were studied by subsequent InAs deposition after laser irradiation. Preferential nucleation in nano holes were found in the experiments. This study provides a novel technique leading to site controlled to InAs/GaAs (001) QDs fabrication.", "author_names": [ "C Chen", "Linyun Yang", "Changwei Deng", "Xinning Yang", "Lili Miao", "Zhenwu Shi", "Changsi Peng" ], "corpus_id": 139503341, "doc_id": "139503341", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Surface modification on InAs wetting layer by in situ pulsed laser and the effets on quantum dot growth", "venue": "Other Conferences", "year": 2018 }, { "abstract": "We have demonstrated the selective area growth of self assembled InAs quantum dots (QDs) in the desired regions by using a template composed of InAs QD arrays. These InAs QDs were fabricated by the use of a specially designed atomic force microscope cantilever, referred to as the Nano Jet Probe (NJP) Using the NJP, two dimensional arrays of ordered In nano dots were fabricated in the selected square regions on a GaAs substrate and directly converted to InAs QD arrays by subsequent annealing by the irradiation of As flux. By using the converted QD arrays as strain templates, self organized InAs QDs were formed in the selected square regions. These InAs QD arrays were used for the further stacking of QDs, and photoluminescence emission was confirmed from the fabricated stacked QD structure.", "author_names": [ "Shunsuke Ohkouchi", "Yoshimasa Sugimoto", "Nobuhiko Ozaki", "Hiroshi Ishikawa", "Kiyoshi Asakawa" ], "corpus_id": 122620943, "doc_id": "122620943", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Molecular beam epitaxial growth of site controlled InAs quantum dot arrays using templates fabricated by the Nano Jet Probe method", "venue": "", "year": 2008 }, { "abstract": "We have fabricated GaAs oxides by using atomic force microscope (AFM) assisted anodic oxidation at various bias voltages, Vox, and studied their chemical compositions and thermal stabilities. The oxides grown at bias voltages less than 30 V desorbed after standard thermal cleaning in molecular beam epitaxy, while the oxide patterns fabricated at Vox>=40 V survived on the surface. We have further investigated the chemical composition of the oxides by X ray photoemission spectroscopy. It has been found that the AFM oxides grown at Vox~10 V predominantly consist of Ga2O and GaO, whereas those grown at Vox~50 V contain a Ga2O3 component. This result indicates that the better thermal stability of AFM oxides grown at Vox>=40 V can be attributed to the formation of Ga2O3. We grew a GaAs buffer layer on the oxide nanomasks and obtained nanoholes. After supplying InAs, selective dot nucleation took place in the nanoholes, resulting in successful formation of site controlled QDs.", "author_names": [ "Kyu Man Cha", "Kenji Shibata", "Isao Horiuchi", "Masao Kamiko", "Ryoichi Yamamoto", "Kazuhiko Hirakawa" ], "corpus_id": 93464291, "doc_id": "93464291", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Chemical composition and thermal stability of GaAs oxides grown by AFM anodic oxidation for site controlled growth of InAs quantum dots", "venue": "", "year": 2011 }, { "abstract": "We have successfully fabricated high density two dimensional indium (In) nano dot arrays on a GaAs substrate with periods of 50 nm. These nano dot structures were formed using an atomic force microscope (AFM) probe with a specially designed cantilever (the Nano Jet Probe) having a hollow pyramidal tip with a sub micron size aperture on the apex and an In reservoir tank within the stylus. These ordered In nano dot arrays can be directly converted to InAs quantum dot (QD) arrays by subsequent irradiation of arsenic flux in the molecular beam epitaxy chamber, which is connected to the AFM chamber through an ultra high vacuum (UHV) tunnel.", "author_names": [ "Shunsuke Ohkouchi", "Y Nakamura", "Hitoshi Nakamura", "Kiyoshi Asakawa" ], "corpus_id": 135599548, "doc_id": "135599548", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Indium nano dot arrays formed by field induced deposition with a Nano Jet Probe for site controlled InAs/GaAs quantum dots", "venue": "", "year": 2004 }, { "abstract": "Abstract We have successfully and reproducibly fabricated uniform indium (In) nano dots at a selected point. Nano dot formation was realized using an atomic force microscope (AFM) probe with a specially designed cantilever, which was equipped with a hollow pyramidal tip with a sub micron size aperture on the apex and an In reservoir tank within the stylus. The In nano dots formed in this study can be directly converted to InAs quantum dots by subsequent irradiation of arsenic flux in the molecular beam epitaxy chamber, which is connected to the AFM chamber through an ultra high vacuum tunnel.", "author_names": [ "Shunsuke Ohkouchi", "Y Nakamura", "Hitoshi Nakamura", "Kiyoshi Asakawa" ], "corpus_id": 121227677, "doc_id": "121227677", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Nano probe assisted technology of indium nano dot formation for site controlled InAs/GaAs quantum dots", "venue": "", "year": 2004 }, { "abstract": "We propose a new nano probe assisted technique which enables the formation of site controlled InAs quantum dots (QDs) High density two dimensional indium (In) nano dot arrays on a GaAs substrate were fabricated by using a specially designed atomic force microscope (AFM) probe (the Nano Jet Probe) This developed probe has a hollow pyramidal tip with a sub micron size aperture on the apex and an In reservoir tank within the stylus. By applying a voltage pulse between the pyramidal tip and the sample, In clusters were extracted from the reservoir tank within the stylus through the aperture, resulting in the In nano dot formation. These In nano dots can be directly converted to InAs QD arrays by subsequent irradiation of arsenic flux.", "author_names": [ "Shunsuke Ohkouchi", "Yusui Nakamura", "Hitoshi Nakamura", "Kiyoshi Asakawa" ], "corpus_id": 93895605, "doc_id": "93895605", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Site control technology for InAs quantum dot formation by direct deposition of indium nano dots with a nano jet probe", "venue": "", "year": 2003 }, { "abstract": "We havedemonstrated theselective areagrowth ofhighdensity InAsquantum dots (QDs)inthesquare regions byusing site controlled InAsdots that wereformed inthedesired regions astemplates. These fabricated InAsdots forthetemplates wereenabled bytheuseofa specially designed atomic force microscope (AFM)cantilever, referred toastheNano Jet Probe(NJP) UsingtheNJP,two dimensional (2D)arrays ofordered Innano dots were fabricated inthedesired square regions onaGaAssubstrate. These Innano dots weredirectly converted toInAsQD arrays bysubsequent annealing withirradiation ofarsenic flux. Byusing theconverted QD arrays asstrain templates, self organized InAsQDswithhighdensity were formed intheselected square regions.", "author_names": [ "Shunsuke Ohkouchi", "Yoshimasa Sugimoto", "Nobuhiko Ozaki", "Hiroshi Ishikawa" ], "corpus_id": 135822048, "doc_id": "135822048", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "SELECTIVEFORMATION OFHIGH DENSITYInAs QUANTUM DOT ARRAYS USINGTEMPLATES FABRICATEDBYTHE NANO JETPROBE", "venue": "", "year": 2007 } ]
Efficient radical-based light-emitting diodes
[ { "abstract": "Organic light emitting diodes (OLEDs)1 5, quantum dot based LEDs6 10, perovskite based LEDs11 13 and micro LEDs14,15 have been championed to fabricate lightweight and flexible units for next generation displays and active lighting. Although there are already some high end commercial products based on OLEDs, costs must decrease whilst maintaining high operational efficiencies for the technology to realise wider impact. Here we demonstrate efficient action of radical based OLEDs16, whose emission originates from a spin doublet, rather than a singlet or triplet exciton. While the emission process is still spin allowed in these OLEDs, the efficiency limitations imposed by triplet excitons are circumvented for doublets. Using a luminescent radical emitter, we demonstrate an OLED with maximum external quantum efficiency of 27 per cent at a wavelength of 710 nanometres the highest reported value for deep red and infrared LEDs. For a standard closed shell organic semiconductor, holes and electrons occupy the highest occupied and lowest unoccupied molecular orbitals (HOMOs and LUMOs) respectively, and recombine to form singlet or triplet excitons. Radical emitters have a singly occupied molecular orbital (SOMO) in the ground state, giving an overall spin 1/2 doublet. If as expected on energetic grounds both electrons and holes occupy this SOMO level, recombination returns the system to the ground state, giving no light emission. However, in our very efficient OLEDs, we achieve selective hole injection into the HOMO and electron injection to the SOMO to form the fluorescent doublet excited state with near unity internal quantum efficiency.Organic light emitting devices containing radical emitters can achieve an efficiency of 27 per cent at deep red and infrared wavelengths based on the excitation of spin doublets, rather than singlet or triplet states.", "author_names": [ "Xin Ai", "E W Evans", "Shengzhi Dong", "Alexander J Gillett", "Haoqing Guo", "Yingxin Chen", "Timothy J H Hele", "Richard H Friend", "Feng Li" ], "corpus_id": 53719327, "doc_id": "53719327", "n_citations": 170, "n_key_citations": 2, "score": 1, "title": "Efficient radical based light emitting diodes with doublet emission", "venue": "Nature", "year": 2018 }, { "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": 0, "title": "Light emitting diodes based on conjugated polymers", "venue": "Nature", "year": 1990 }, { "abstract": "A comprehensive review of the literature on electron transport materials (ETMs) used to enhance the performance of organic light emitting diodes (OLEDs) is presented. The structure property performance relationships of many classes of ETMs, both small molecule and polymer based, that have been widely used to improve OLED performance through control of charge injection, transport, and recombination are highlighted. The molecular architecture, electronic structure (electron affinity and ionization potential) thin film processing, thermal stability, morphology, and electron mobility of diverse organic ETMs are discussed and related to their effectiveness in improving OLED performance (efficiency, brightness, and drive voltage) Some issues relating to the experimental procedures for the estimation of relevant material properties such as electron affinity and electron mobility are discussed. The design of multifunctional electroluminescent polymers whereby light emission and electron and hole transport pro.", "author_names": [ "Abhishek P Kulkarni", "Christopher J Tonzola", "Andreas Babel", "Samson A Jenekhe" ], "corpus_id": 136636815, "doc_id": "136636815", "n_citations": 1277, "n_key_citations": 4, "score": 0, "title": "Electron Transport Materials for Organic Light Emitting Diodes", "venue": "", "year": 2004 }, { "abstract": "Phosphorescent organic light emitting diodes (PhOLEDs) unfurl a bright future for the next generation of flat panel displays and lighting sources due to their merit of high quantum efficiency compared with fluorescent OLEDs. This critical review focuses on small molecular organic host materials as triplet guest emitters in PhOLEDs. At first, some typical hole and electron transport materials used in OLEDs are briefly introduced. Then the hole transport type, electron transport type, bipolar transport host materials and the pure hydrocarbon compounds are comprehensively presented. The molecular design concept, molecular structures and physical properties such as triplet energy, HOMO/LUMO energy levels, thermal and morphological stabilities, and the applications of host materials in PhOLEDs are reviewed (152 references)", "author_names": [ "Youtian Tao", "Chuluo Yang", "Jingui Qin" ], "corpus_id": 38139817, "doc_id": "38139817", "n_citations": 916, "n_key_citations": 4, "score": 0, "title": "Organic host materials for phosphorescent organic light emitting diodes.", "venue": "Chemical Society reviews", "year": 2011 }, { "abstract": "The inherent flexibility afforded by molecular design has accelerated the development of a wide variety of organic semiconductors over the past two decades. In particular, great advances have been made in the development of materials for organic light emitting diodes (OLEDs) from early devices based on fluorescent molecules to those using phosphorescent molecules. In OLEDs, electrically injected charge carriers recombine to form singlet and triplet excitons in a 1:3 ratio; the use of phosphorescent metal organic complexes exploits the normally non radiative triplet excitons and so enhances the overall electroluminescence efficiency. Here we report a class of metal free organic electroluminescent molecules in which the energy gap between the singlet and triplet excited states is minimized by design, thereby promoting highly efficient spin up conversion from non radiative triplet states to radiative singlet states while maintaining high radiative decay rates, of more than 106 decays per second. In other words, these molecules harness both singlet and triplet excitons for light emission through fluorescence decay channels, leading to an intrinsic fluorescence efficiency in excess of 90 per cent and a very high external electroluminescence efficiency, of more than 19 per cent, which is comparable to that achieved in high efficiency phosphorescence based OLEDs.", "author_names": [ "Hiroki Uoyama", "Kenichi Goushi", "Katsuyuki Shizu", "Hiroko Nomura", "Chihaya Adachi" ], "corpus_id": 4376505, "doc_id": "4376505", "n_citations": 3562, "n_key_citations": 27, "score": 0, "title": "Highly efficient organic light emitting diodes from delayed fluorescence", "venue": "Nature", "year": 2012 }, { "abstract": "Compact high efficiency ultraviolet solid state light sources such as light emitting diodes (LEDs) and laser diodes are of considerable technological interest as alternatives to large, toxic, low efficiency gas lasers and mercury lamps. Microelectronic fabrication technologies and the environmental sciences both require light sources with shorter emission wavelengths: the former for improved resolution in photolithography and the latter for sensors that can detect minute hazardous particles. In addition, ultraviolet solid state light sources are also attracting attention for potential applications in high density optical data storage, biomedical research, water and air purification, and sterilization. Wide bandgap materials, such as diamond and III V nitride semiconductors (GaN, AlGaN and AlN; refs 3 10) are potential materials for ultraviolet LEDs and laser diodes, but suffer from difficulties in controlling electrical conduction. Here we report the successful control of both n type and p type doping in aluminium nitride (AlN) which has a very wide direct bandgap of 6 eV. This doping strategy allows us to develop an AlN PIN (p type/intrinsic/n type) homojunction LED with an emission wavelength of 210 nm, which is the shortest reported to date for any kind of LED. The emission is attributed to an exciton transition, and represents an important step towards achieving exciton related light emitting devices as well as replacing gas light sources with solid state light sources.", "author_names": [ "Yoshitaka Taniyasu", "Makoto Kasu", "Toshiki Makimoto" ], "corpus_id": 4373542, "doc_id": "4373542", "n_citations": 1361, "n_key_citations": 30, "score": 0, "title": "An aluminium nitride light emitting diode with a wavelength of 210 nanometres", "venue": "Nature", "year": 2006 }, { "abstract": "Organic electroluminescent devices are light emitting diodes in which the active materials consist entirely of organic materials. Here, the fabrication of a white light emitting organic electroluminescent device made from vacuum deposited organic thin films is reported. In this device, three emitter layers with different carrier transport properties, each emitting blue, green, or red light, are used to generate white light. Bright white light, over 2000 candelas per square meter, nearly as bright as a fluorescent lamp, was successfully obtained at low drive voltages such as 15 to 16 volts. The applications of such a device include paper thin light sources, which are particularly useful for places that require lightweight illumination devices, such as in aircraft and space shuttles. Other uses are a backlight for liquid crystal display as well as full color displays, achieved by combining the emitters with micropatterned color filters.", "author_names": [ "Junji Kido" ], "corpus_id": 22265451, "doc_id": "22265451", "n_citations": 1470, "n_key_citations": 1, "score": 0, "title": "Multilayer White Light Emitting Organic Electroluminescent Device", "venue": "Science", "year": 1995 }, { "abstract": "Since the successful demonstration of a blue light emitting diode (LED)1, potential materials for making short wavelength LEDs and diode lasers have been attracting increasing interest as the demands for display, illumination and information storage grow2,3,4. Zinc oxide has substantial advantages including large exciton binding energy, as demonstrated by efficient excitonic lasing on optical excitation5,6. Several groups have postulated the use of p type ZnO doped with nitrogen, arsenic or phosphorus7,8,9,10, and even p n junctions11,12,13. However, the choice of dopant and growth technique remains controversial and the reliability of p type ZnO is still under debate14. If ZnO is ever to produce long lasting and robust devices, the quality of epitaxial layers has to be improved as has been the protocol in other compound semiconductors15. Here we report high quality undoped films with electron mobility exceeding that in the bulk. We have used a new technique to fabricate p type ZnO reproducibly. Violet electroluminescence from homostructural p i n junctions is demonstrated at room temperature.", "author_names": [ "Atsushi Tsukazaki", "Akira Ohtomo", "Takeyoshi Onuma", "M Ohtani", "Takayuki Makino", "Masatomo Sumiya", "Keita Ohtani", "Shigefusa F Chichibu", "Shunro Fuke", "Yusaburo Segawa", "Hideo Ohno", "Hideomi Koinuma", "Masashi Kawasaki" ], "corpus_id": 137286849, "doc_id": "137286849", "n_citations": 1859, "n_key_citations": 10, "score": 0, "title": "Repeated temperature modulation epitaxy for p type doping and light emitting diode based on ZnO", "venue": "", "year": 2004 }, { "abstract": "Since the breakthrough by Kodak in 1987, organic light emitting diodes (OLEDs) have been seen as one of the most promising technologies for future displays. A number of materials have been developed and improved in order to fulfil the requirements of this application. The materials differ from one another by their structure but also by the mechanism involved in the electroluminescence produced (fluorescence versus phosphorescence) When properly stacked, these materials result in a device that can achieve the required high efficiency and long lifetime. Such red, green and blue devices can then be combined in matrices to become the core of a display. Building up these structures onto a display backplane is one of the challenges facing the industry. The circuitry for driving the pixels can be adapted to the OLED, sometimes at the expense of the simplicity of the display, but bearing in mind that the fabrication process must remain industrially viable. 2006 Society of Chemical Industry", "author_names": [ "Bernard Geffroy", "Philippe Le Roy", "Christophe Prat" ], "corpus_id": 32982758, "doc_id": "32982758", "n_citations": 650, "n_key_citations": 11, "score": 0, "title": "Organic light emitting diode (OLED) technology: materials, devices and display technologies", "venue": "", "year": 2006 }, { "abstract": "Organic light emitting diodes (OLEDs) based on vacuum deposited small molecules have undergone significant progress since the first efficient double layered OLEDs were reported in 1987 by Tang and Van Slyke. Recently, solution processed small molecular OLEDs are also drawing more and more research attention, as such a technology combines advantages of the facile synthesis of small molecules and the low cost solution process like polymers. The performance of OLEDs made by solution process is gradually catching up with their vacuum deposited counterparts. This feature article will review the device structures adopted to achieve high performance solution processed OLEDs, the development of solution processable small molecules, and the comparisons of the different nature of the films and devices fabricated by solution process or by vacuum deposition. Finally, the prospects and remaining problems will be discussed.", "author_names": [ "Lian Duan", "Liudong Hou", "Tae-Woo Lee", "Juan Qiao", "De-qiang Zhang", "Guifang Dong", "Liduo Wang", "Yong Qiu" ], "corpus_id": 93890838, "doc_id": "93890838", "n_citations": 487, "n_key_citations": 3, "score": 0, "title": "Solution processable small molecules for organic light emitting diodes", "venue": "", "year": 2010 } ]
β-Ga2O3 MOSFETs for radio frequency operation
[ { "abstract": "In this Letter, we present direct current (DC) small signal radio frequency (RF) and large signals with pulsed and continuous wave (CW) studies and characterization on oxygen annealed (OA) b Ga2O3 metal oxide semiconductor field effect transistors (MOSFETs) with significantly improved CW output power density (Pout) when compared to other b Ga2O3 RF devices. The OA process is found to be useful in compensating and neutralizing the donors in the unintentionally doped (UID) buffer layer and, hence, suppressing a second depletion effect in this UID layer. The device demonstrates a peak DC drain current of 200 mA/mm, a transconductance of 11 mS/mm, and an on/off ratio of 109. Small signal RF characterization indicates a cut off frequency and maximum oscillation frequency (fT/fmax) of 1.8 GHz and 4.2 GHz, respectively. The device also shows an output power (Pout)/peak power added efficiency (PAE)/gain of 0.4 W/mm/10%/3.2 dB and 0.43 W/mm/12%/3.6 dB for CW and pulsed signals, respectively, at an operation frequency of 1 GHz.", "author_names": [ "Yuanjie Lv", "Xingchang Fu", "Yanni Zhang", "Pengfei Dong", "Hanghai Du", "Shixiong Liang", "Tingting Han", "Jincheng Zhang", "Zhihong Feng", "Hui Zhou", "Shujun Cai", "Yue Hao" ], "corpus_id": 224853458, "doc_id": "224853458", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Oxygen annealing impact on b Ga2O3 MOSFETs: Improved pinch off characteristic and output power density", "venue": "", "year": 2020 }, { "abstract": "We demonstrate a <inline formula> <tex math notation=\"LaTeX\"\\beta /tex math>/inline formula> Ga<sub>2</sub>O<sub>3</sub> MOSFET with record high transconductance <inline formula> <tex math notation=\"LaTeX\"{g}_{m} /tex math>/inline formula> of 21 mS/mm and extrinsic cutoff frequency <inline formula> <tex math notation=\"LaTeX\"{f}_{T} /tex math>/inline formula> and maximum oscillating frequency <inline formula> <tex math notation=\"LaTeX\"{f}_{\\max /tex math>/inline formula> of 3.3 and 12.9 GHz, respectively, enabled by implementing a new highly doped ohmic cap layer with a sub micron gate recess process. RF performance was further verified by CW Class A power measurements with passive source and load tuning at 800 MHz, resulting in <inline formula> <tex math notation=\"LaTeX\"{P}_{{OUT} /tex math>/inline formula> power gain, and power added efficiency of 0.23 W/mm, 5.1 dB, and 6.3% respectively. These preliminary results indicate potential for monolithic or heterogeneous integration of power switch and RF devices using <inline formula> <tex math notation=\"LaTeX\"\\beta /tex math>/inline formula> Ga<sub>2</sub>O<sub>3</sub>", "author_names": [ "Andrew J Green", "Kelson D Chabak", "Michele Baldini", "Neil A Moser", "Ryan Gilbert", "Robert C Fitch", "Gunter P Wagner", "Zbigniew Galazka", "J P McCandless", "Antonio Crespo", "Kevin D Leedy", "Gregg H Jessen" ], "corpus_id": 31274290, "doc_id": "31274290", "n_citations": 155, "n_key_citations": 5, "score": 1, "title": "\\beta$ Ga2O3 MOSFETs for Radio Frequency Operation", "venue": "IEEE Electron Device Letters", "year": 2017 }, { "abstract": "b Ga2O3 metal oxide semiconductor field effect transistors (MOSFETs) with gate lengths (Lg) of 50 1000 nm were fabricated, employing a thin channel layer formed by a shallow Si ion implantation doping to maintain a high aspect ratio between an Lg and a gate to channel distance. The MOSFETs with Lg 200 nm had a maximum drain current density of about 250 mA/mm and a peak extrinsic transconductance of 17 mS/mm. The short channel effect was well suppressed for the devices with Lg =200 nm, leading to excellent RF device characteristics represented by a record maximum oscillation frequency of 27 GHz at Lg 200 nm. From simple delay time analysis on the MOSFETs, the effective electron velocity passing through a region under the gate was estimated to be about 2 x 106 cm/s. Moreover, it was analyzed that the parasitic channel charging delay occupied a substantial proportion of the total delay due to a large sheet resistance of the Ga2O3 channel and thus limited their high frequency device performance. These results suggest that both suppressing the short channel effect with a reduction in Lg to the sub 0.1 mm range and minimizing the access resistance are important to further improve RF device characteristics of Ga2O3 MOSFETs.", "author_names": [ "Takafumi Kamimura", "Yoshiaki Nakata", "Masataka Higashiwaki" ], "corpus_id": 234389884, "doc_id": "234389884", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Delay time analysis in radio frequency b Ga2O3 field effect transistors", "venue": "", "year": 2020 }, { "abstract": "The path to achieving integrated RF and power conversion circuitry using the b Ga2O3 material system is described with regard to the materials high Johnson's RF figure of merit. Recent results, including large signal data at VD 50 V, are provided, showing progress in achieving high voltage RF operation. Additionally, progress in achieving high gain devices through gate length scaling is also benchmarked by a record RF power device with a gate length of 0.5 mm achieving a 2.1 GHz mm f T L G product. These results are compared with state of the art RF devices, and the expectations for b Ga2O3 at this point in its maturity throughout this Letter with future milestones laid out to measure progress. The conclusion includes near and long term projections for b Ga2O3 devices for RF based on the results and projected milestones presented.", "author_names": [ "Neil A Moser", "Kyle J Liddy", "Ahmad E Islam", "Nicholas C Miller", "Kevin D Leedy", "Thaddeus J Asel", "Shin Mou", "Andrew J Green", "Kelson D Chabak" ], "corpus_id": 230586246, "doc_id": "230586246", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Toward high voltage radio frequency devices in b Ga2O3", "venue": "", "year": 2020 }, { "abstract": "We propose stability enhancement of a high frequency (1.2MHz) DC distribution network comprising numerous feedback controlled buck converters by replacing their conventional electro mechanical switches with \\beta $polymorphic Gallium Oxide \\beta \\mathrm{Ga}_{2}\\mathrm{O}_{3} power MOSFETs operated on soft switching. The performance anomaly in terms of output voltage oscillations and poor overall stability resulting from negative incremental impedances have been successfully addressed with the help of the Middlebrook Criterion. Having the highest Johnson's Figure of Merit (2844) among all studied Wide Band Gap (WBG) materials, \\beta \\mathrm{G}\\mathrm{a}_{2}\\mathrm{O}_{3} promises the best Power Frequency operation. In our simulations here, it leads to substantial performance improvement compared to the conventional system design in terms of output voltage oscillation and overall stability of the DCdistribution network Losses have been calculated and analyzed, with regard to the Minimum System Efficiency Degradation versus Maximum Stability Enhancement trade off. Further, we demonstrate the dominance of a solid state switch at the converter input, over a feedback loop at the back end, in securing a system with higher stability.", "author_names": [ "Sudipta Mukherjee", "Dipankar Saha", "Apurba Laha", "Swaroop Ganguly" ], "corpus_id": 231683445, "doc_id": "231683445", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Stability Enhancement of High Frequency DC Distribution Network by Incorporating Wide Bandgap b Ga2O3 Power MOSFET as Switching Element", "venue": "2020 IEEE Electric Power and Energy Conference (EPEC)", "year": 2020 }, { "abstract": "A high frequency diode is an essential component in electrical circuits providing the current rectification function for AC/DC converters, radio frequency detectors, and automotive inverters. Schottky barrier diodes based on wide bandgap semiconductors are promising for the high frequency applications owing to short reverse recovery time that minimizes the energy dissipation during the switching. In this study, we report dynamic characteristics of Schottky junctions composed of a layered oxide metal PdCoO2 and an n type b Ga2O3 substrate. Rectifying current voltage characteristics with reasonably small hysteresis were demonstrated up to a high frequency of 3 MHz in the PdCoO2/b Ga2O3 Schottky junctions. For the on state to off state switching with the current ramp rate of approximately 2 x 1010 A/scm2, the reverse recovery time was as short as 11 ns. The short reverse recovery time was constantly obtained in the operation temperature range of 25 350 degC, showing low loss switching properties of the PdCoO2/b Ga2O3 Schottky junctions. The Schottky barrier height of ~1.78 eV and the ideality factor of ~1.06 were maintained after the 108 times on off switching cycles. The fast switching with less energy dissipation and high durability of the PdCoO2/b Ga2O3 Schottky junctions would be suitable for application in high frequency power devices operating at high temperature.", "author_names": [ "Takayuki Harada", "Atsushi Tsukazaki" ], "corpus_id": 225804795, "doc_id": "225804795", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Dynamic characteristics of PdCoO2/b Ga2O3 Schottky junctions", "venue": "", "year": 2020 }, { "abstract": "Abstract: During the last decade, silicon on insulator (SOI) metal oxide semiconductor field effect transistor (MOSFET) technology has demonstrated its high frequency potential, reaching cut off frequencies close to 500 GHz, and its suitability for commercial applications in harsh environments. For high speed and radio frequency (RF) applications, strained Si and high resistivity Si can be considered, respectively, to enhance carrier mobility and thus current and operation speed, and to minimize the RF substrate losses. Nowadays, substrate resistivity values higher than 5 kO.cm can easily be achieved and high resistivity silicon is widely seen as a promising substrate for radio frequency integrated circuits and mixed signal applications.", "author_names": [ "J P Raskin", "Mostafa Emam" ], "corpus_id": 107866466, "doc_id": "107866466", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Silicon on insulator (SOI) metal oxide semiconductor field effect transistors (MOSFETs) for radio frequency (RF) and analogue applications", "venue": "", "year": 2014 }, { "abstract": "The superior electronic properties of ultra wide bandgap (UWBG) b gallium oxide (b Ga<inf>2</inf>O<inf>3</inf> gives promise to developing power and radio frequency (RF) devices with improved size, weight, and power (SWaP) and efficiency over current state of the art wide bandgap (WBG) devices based on SiC and GaN. However, self heating is viewed as a major challenge that the b Ga<inf>2</inf>O<inf>3</inf> device technology will encounter. b Ga<inf>2</inf>O<inf>3</inf> devices are expected to handle higher power densities than WBG counterparts. However, the thermal conductivity of b Ga<inf>2</inf>O<inf>3</inf> is only on the order of 10 20 W/m K, which is significantly lower than that for GaN or SiC. Therefore, large temperature gradients forming in b Ga<inf>2</inf>O<inf>3</inf> devices during operation can cause thermo mechanical reliability issues. In this work, a micro Raman metrology scheme was established to simultaneously measure the temperature rise and associated thermo elastic stress induced in b Ga<inf>2</inf>O<inf>3</inf> thin films. To decouple the effect of temperature and stress, the proposed scheme utilizes multiple peaks in the b Ga<inf>2</inf>O<inf>3</inf> Raman spectrum. A 1 mm thick halide vapor phase epitaxy (HVPE) b Ga<inf>2</inf>O<inf>3</inf> layer grown on a sapphire substrate and a 3D thermo mechanical multi physics model was utilized to establish the measurement technique. The developed method can be used to determine the stress and temperature in b Ga<inf>2</inf>O<inf>3</inf> epi layers consisting future UWBG electronic devices.", "author_names": [ "Bikramjit Chatterjee", "Jacob H Leach", "Sarit Dhar", "Sukwon Choi" ], "corpus_id": 51720753, "doc_id": "51720753", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Temperature and Stress Metrology of Ultra Wide Bandgap b Ga2O3 Thin Films", "venue": "2018 17th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)", "year": 2018 }, { "abstract": "Junctionless Metal Oxide Semiconductor Field Effect Transistor (JL MOSFET) is one of the promising candidate to replace the junction based MOSFET for upcoming technology nodes. Semiconductor industries are continuously urging for large ON current with the low OFF current and low specific on resistance. However, high ON current is achieved in Conventional (Conv. JL DG MOSFET by using high doping concentration at the cost of high OFF current which leads depletion mode operation. Moreover, low doping, narrow channel thickness and high work function gate materials are using to operate Conv. JL DG MOSFET in enhancement mode (V th 0 V for N JL DG MOSFET, V th 0 V for P JL DG MOSFET) but ON current is reduced in all above mentioned solutions. To overcome the above mentioned problems, a new architecture is developed called Recessed JL DG MOSFET. In Recessed JL DG MOSFET silicon region is recessed under the gate region and some gate portion is extended towards source and drain region. Recessed JL DG MOSFET shows the same ON current as achieved in Conv. JL DG MOSFET with very low OFF current (leakage current) by considering high doping concentration. Surface potential, electron density, energy band distribution, drain current have been investigated to proof the enhancement mode operation of Recessed JL DG MOSFET. Figure of Merits (FOMs) for RF performance such as Trans conductance, capacitance and intrinsic power gain (S 21 Trans conductance frequency product (TFP) Gain frequency product (GFP) and Gain trans conductance frequency product (GTFP) have also investigated of Recessed JL DG MOSFET.", "author_names": [ "" ], "corpus_id": 210122846, "doc_id": "210122846", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Investigation of Recessed Junctionless Double Gate MOSFET for Radio Frequency Applications", "venue": "Silicon", "year": 2020 }, { "abstract": "This paper presents a new extraction method for source and drain (S/D) series resistances of silicon nanowire (SNW) metal oxide semiconductor field effect transistors (MOSFETs) based on small signal radio frequency (RF) analysis. The proposed method can be applied to the extraction of S/D series resistances for SNW MOSFETs with finite off state channel resistance as well as gate bias dependent on state resistive components realized by 3 dimensional (3 D) device simulation. The series resistances as a function of frequency and gate voltage are presented and compared with the results obtained by an existing method with infinite off state channel resistance model. The accuracy of the newly proposed parameter extraction method has been successfully verified by Z22 and Y parameters up to 100 GHz operation frequency.", "author_names": [ "Jae Hwa Hwa", "Young Jun Yoon", "Hwan Gi Lee", "Gwan Min Yoo", "Eou Sik Cho", "Seongjae Cho", "Jung-Hee Lee", "In Man Kang" ], "corpus_id": 12382894, "doc_id": "12382894", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A reliable extraction method for source and drain series resistances in silicon nanowire metal oxide semiconductor field effect transistors (MOSFETs) based on radio frequency analysis.", "venue": "Journal of nanoscience and nanotechnology", "year": 2014 } ]
Transparent conducting oxide semiconductors for transparent electrodes
[ { "abstract": "The present status and prospects for further development of polycrystalline or amorphous transparent conducting oxide (TCO) semiconductors used for practical thin film transparent electrode applications are presented in this paper. The important TCO semiconductors are impurity doped ZnO, In2O3 and SnO2 as well as multicomponent oxides consisting of combinations of ZnO, In2O3 and SnO2, including some ternary compounds existing in their systems. Development of these and other TCO semiconductors is important because the expanding need for transparent electrodes for optoelectronic device applications is jeopardizing the availability of indium tin oxide (ITO) whose main constituent, indium, is a very expensive and scarce material. Al and Ga doped ZnO (AZO and GZO) semiconductors are promising as alternatives to ITO for thin film transparent electrode applications. In particular, AZO thin films, with a low resistivity of the order of 10 5 O cm and source materials that are inexpensive and non toxic, are the best candidates. However, further development of the deposition techniques, such as magnetron sputtering or vacuum arc plasma evaporation, as well as of the targets is required to enable the preparation of AZO and GZO films on large area substrates with a high deposition rate.", "author_names": [ "Tadatsugu Minami" ], "corpus_id": 93242002, "doc_id": "93242002", "n_citations": 1757, "n_key_citations": 37, "score": 1, "title": "Transparent conducting oxide semiconductors for transparent electrodes", "venue": "", "year": 2005 }, { "abstract": "The various applications of transparent conducting oxides (TCO) e.g. as electrodes in flat panel displays and solar cells or as low emissivity coatings have stimulated extensive research on their fabrication and properties. Recent experimental and theoretical studies of defect properties have considerably improved the understanding of the limitations of the electrical conductivity of both n and p type transparent conductors and of the structural and electronic surface properties of the most important TCO materials. Development of emerging and future applications in the area of transparent thin film electronics with oxide semiconductors as well as the improvement of existing applications require a detailed control of the Fermi level position in the bulk and at surfaces and interfaces of polycrystalline and amorphous TCO materials. This feature article describes how the important parameters for such control can be identified using photoelectron spectroscopy with in situ sample preparation. The parameters influencing doping, work functions, ionization potentials, and surface band bending as well as energy band alignment at interfaces are described and discussed providing a fundamental understanding of important material properties for tailoring TCOs in electronic devices.", "author_names": [ "Andreas Klein" ], "corpus_id": 98561211, "doc_id": "98561211", "n_citations": 108, "n_key_citations": 4, "score": 0, "title": "Transparent Conducting Oxides: Electronic Structure Property Relationship from Photoelectron Spectroscopy with in situ Sample Preparation", "venue": "", "year": 2012 }, { "abstract": "This dissertation focuses on characterizing the nanoscale and surface averaged electrical properties of transparent conducting oxide (TCO) electrodes such as indium tin oxide (ITO) and transparent metal oxide (MO) electron selective interlayers (ESLs) such as zinc oxide (ZnO) the ability of these materials to rapidly extract photogenerated charges from organic semiconductors (OSCs) used in organic photovoltaic (OPV) cells, and evaluating their impact on the power conversion efficiency (PCE) of OPV devices. In Chapter 1, we will introduce the fundamental principles regarding the need for low cost power generation, the benefits of OPV technologies, as well as the key principles that govern the operation of OPV devices and the key innovations that have advanced this technology. In Chapter 2 of this dissertation, we demonstrate an innovative application of conductive probe atomic force microscopy (CAFM) to map the nanoscale electrical heterogeneity at the interface between an electrode, such as ITO, and an OSC such as the p type OSC copper phthalocyanine (CuPc)(MacDonald et al. (2012) ACS Nano, 6, p. 9623) In this work we collected arrays of J V curves, using a CAFM probe as the top contact of CuPc/ITO systems, to map the local J V responses. By comparing J V responses to known models for charge transport, we were able to determine if the local rate limiting step for charge transport is through the OSC (ohmic) or the CuPc/ITO interface (nonohmic) These results strongly correlate with device PCE, as demonstrated through the controlled addition of insulating alkylphosphonic acid self assembled monolayers (SAMs) at the ITO/CuPc interface. Subsequent chapters focus on the electrical property characterization of RF magnetron sputtered ZnO (sp ZnO) ESL films on ITO substrates. We have shown that the energetic alignment of ESLs and the organic semiconducting (OSC) active materials plays a critical role in determining the PCE of OPV devices and the appearance of, or lack thereof, UV light soaking sensitivity. For ZnO and fullerene interfaces, we have shown that either minimizing the oxygen partial pressure during ZnO deposition or exposure of ZnO to UV light minimizes the energetic offset at this interface and maximizes device PCE. We have used a combination of device testing, device modeling, and impedance spectroscopy to fully characterize the effects that energetic alignment has on the charge carrier transport and charge carrier distribution within the OPV device. This work can be found in Chapter 3 of this dissertation and is in preparation for publication. We have also shown that the local properties of sp ZnO films varies as a function of the underlying ITO crystal face. We show that the local ITO crystal face determines the local nucleation and growth of the sp ZnO films. We demonstrate that this effects the morphology, the chemical resistance to etching as well as the surface electrical properties of the sp ZnO films. This is likely due to differences in the surface mobility of sputtered Zn and O atoms on these.", "author_names": [ "Gordon A MacDonald" ], "corpus_id": 136484646, "doc_id": "136484646", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Nanoscale Characterization of the Electrical Properties of Oxide Electrodes at the Organic Semiconductor Oxide Electrode Interface in Organic Solar Cells", "venue": "", "year": 2015 }, { "abstract": "Transparent conducting oxides (TCOs) and transparent oxide semiconductors (TOSs) have become necessary materials for a variety of applications in the information and energy technologies, ranging from transparent electrodes to active electronics components. Perovskite barium stannate (BaSnO3) a new TCO or TOS system, is a potential platform for realizing optoelectronic devices and observing novel electronic quantum states due to its high electron mobility, excellent thermal stability, high transparency, structural versatility, and flexible doping controllability. This article reviews recent progress in the doped BaSnO3 system, discussing the wide range of physical properties, electron scattering mechanism, and demonstration of key semiconducting devices such as pn diodes and field effect transistors. Moreover, we discuss the pathways to achieving two dimensional electron gases at the interface between BaSnO3 and other perovskite oxides and describe remaining challenges for observing novel quantum phenomen.", "author_names": [ "Woong-Jhae Lee", "Hyung Kim", "Jeonghun Kang", "D H Jang", "Tai-hoon Kim", "Jeong Hyuk Lee", "Kee Hoon Kim" ], "corpus_id": 119002264, "doc_id": "119002264", "n_citations": 66, "n_key_citations": 1, "score": 0, "title": "Transparent Perovskite Barium Stannate with High Electron Mobility and Thermal Stability", "venue": "", "year": 2017 }, { "abstract": "Recently, a new field in photovoltaics (PV) has emerged, focusing on solar cells that are entirely based on metal oxide semiconductors. The all oxide PV approach is very attractive due to the chemical stability, nontoxicity, and abundance of many metal oxides that potentially allow manufacturing under ambient conditions. Already today, metal oxides (MOs) are widely used as components in PV cells such as transparent conducting front electrodes or electron transport layers, while only very few MOs have been used as light absorbers. In this Perspective, we review recent developments of all oxide PV systems, which until today were mostly based on Cu2O as an absorber. Furthermore, ferroelectric BiFeO3 based PV systems are discussed, which have recently attracted considerable attention. The performance of all oxide PV cells is discussed in terms of general PV principles, and directions for progress are proposed, pointing toward the development of novel metal oxide semiconductors using combinatorial methods.", "author_names": [ "Sven Ruhle", "Assaf Y Anderson", "Hannah-Noa Barad", "Benjamin Kupfer", "Yaniv Bouhadana", "Eli Rosh-Hodesh", "Arie Zaban" ], "corpus_id": 45157112, "doc_id": "45157112", "n_citations": 219, "n_key_citations": 2, "score": 0, "title": "All Oxide Photovoltaics.", "venue": "The journal of physical chemistry letters", "year": 2012 }, { "abstract": "The need for a high performance, earth abundant transparent conducting oxides (TCOs) is ever present in the expanding electronics and photovoltaics industry. TCOs possess large optical band gaps 3.1 eV) in order to avoid the absorption of visible light, resistivities as low as ~10 5 Ocm as well as large carrier concentrations 1020 cm 3) All the industrially used TCOs (i.e. ITO, ZnO:Al, SnO2:F) are n type, which limits their applications to those of transparent electrodes. To extend the utility and applications of TCOs further, p n junctions composed of all oxide TCOs must be achieved, meaning that the discovery of a high performance, p type TCO has become a much sought after goal for materials scientists. Decades of attempts to fabricate the elusive p type TCO have been centred on doping of the natively n type TCOs to make them p type, with little success. Arguably the flagship TCO material is In2O3:Sn (Tin doped Indium Oxide, ITO) with resistivities as low as 10 5 Ocm making this material ideal for consumer electronics. A main limitation of this material however, is the high cost of indium and the rarity of the element in the earth's crust which drives the search for a cheaper alternative. Stannia (SnO2 or stannic oxide) is an n type, wide band gap oxide semiconductor which crystallizes in the tetragonal rutile (Cassiterite) structure. It possesses a fundamental band gap of 3.6 eV at the Gamma point, can achieve conductivities of ~104 Scm 1 when donor doped, and displays a high thermal and chemical stability, making it excellent for transparent conducting oxide (TCO) and gas sensing applications. High conductivities can be achieved by doping with Antimony (Sb) or Fluorine (F) which are the most common choice for donor dopant in SnO2 resulting in resistivities as low as 10 4 Ocm, which falls short of the performance of ITO. One reason is that these these dopants appear to be inherently self limiting. In this presentation I will present a survey of the defect chemistry of SnO2, explaining why the material can never be made p type, and identifying novel doping strategies which can surpass the self limitations of the currently utilsed donor dopants.", "author_names": [ "Jana Tittmann-Otto", "Martin T Hartmann", "J Ullrich", "Stefan Schulz", "" ], "corpus_id": 211571988, "doc_id": "211571988", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Workshop on Charge Trapping Defects in Semiconductors and Insulators", "venue": "", "year": 2017 }, { "abstract": "Abstract Dense tin oxide based ceramic semiconductors have a high potential as electrodes for aluminum production, glass industry, sputtering targets for transparent conducting thin films, varistors, and thermoelectrics due to their specific electrical properties, high corrosion resistance and ability to withstand high temperatures. The application of these ceramics is still limited because of the necessity to reach density of 99% of TD or greater and high electrical conductivity, and because of the manufacturing difficulties to produce components of different shapes and sizes with low cost. The paper reviews the results of the works conducted towards obtaining tin oxide based ceramics with density up to 99.5+ of TD through low temperature pressureless sintering. The selected sintering aids/dopants and firing conditions promoted both liquid phase sintering and electrical conductivity. The uniform microcrystalline structure is obtained.", "author_names": [ "Eugene Medvedovski" ], "corpus_id": 136559905, "doc_id": "136559905", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Tin oxide based ceramics of high density obtained by pressureless sintering", "venue": "", "year": 2017 }, { "abstract": "Sodium beta alumina (SBA) has high two dimensional conductivity, owing to mobile sodium ions in lattice planes, between which are insulating AlO(x) layers. SBA can provide high capacitance perpendicular to the planes, while causing negligible leakage current owing to the lack of electron carriers and limited mobility of sodium ions through the aluminium oxide layers. Here, we describe sol gel beta alumina films as transistor gate dielectrics with solution deposited zinc oxide based semiconductors and indium tin oxide (ITO) gate electrodes. The transistors operate in air with a few volts input. The highest electron mobility, 28.0 cm2 V( 1) s( 1) was from zinc tin oxide (ZTO) with an on/off ratio of 2 x 10(4) ZTO over a lower temperature, amorphous dielectric, had a mobility of 10 cm2 V( 1) s( 1) We also used silicon wafer and flexible polyimide aluminium foil substrates for solution processed n type oxide and organic transistors. Using poly(3,4 ethylenedioxythiophene) poly(styrenesulphonate) conducting polymer electrodes, we prepared an all solution processed, low voltage transparent oxide transistor on an ITO glass substrate.", "author_names": [ "Bhola Nath Pal", "Bal M Dhar", "Kevin C See", "Howard E Katz" ], "corpus_id": 5768955, "doc_id": "5768955", "n_citations": 251, "n_key_citations": 2, "score": 0, "title": "Solution deposited sodium beta alumina gate dielectrics for low voltage and transparent field effect transistors.", "venue": "Nature materials", "year": 2009 }, { "abstract": "Tin oxide, an n type wide direct band gap semiconductoris promisingly used material for detection of wide variety of gases such as LPG, CO, and volatile organic compound (VOC'S) and many different applications such as high performance capacitive behaviour, transparent conducting electrodes, transistors, light emitting diodes (LEDs) and solar cells. The electrical conductivity of the nanoparticles are dependent on the density of preadsorbed oxygen ions on its surface. The detection mechanism of gas is based on the reversible change of conductivity of the surface of metal oxide semiconductors particles/grains induced by gas solid interaction. Several strategies have been adopted to enhance the performance of gas sensors; including doping with aliovalent ions (e.g. Cu, Zn, In) catalytically active additives.", "author_names": [ "Mahendra Kumar" ], "corpus_id": 99931458, "doc_id": "99931458", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Gas Sensing Properties of Zn Doped TIN Oxide Nanoparticles with Methanol", "venue": "", "year": 2016 }, { "abstract": "One dimensional nanowire arrays directly grown on substrates have been recognized to be superior to two dimensional thin films and nanoparticle films since they demonstrate in general single crystallinity, larger surface area, fast charge separation, and good contact with substrates. Accordingly, they provide an accessible way to the development of high performance devices such as photovoltaic cells, sensors, photocatalysts, electrodes, light emitters, etc. Although high temperature vapor phase synthesis is the most commonly employed method to produce high crystallinity and high density one dimensional nanostructures with high purity, it is not acceptable in terms of the growing demand for the use of TCO (transparent conducting oxide) glass substrates, cost effectiveness, and large scale mass production. Also, it is very difficult to control the precursor vapor pressures to meet the stoichiometry of many compound semiconductors through the vapor phase growth. In this context, there is a high need for the development of appropriate and efficient wet chemical growth methods for one dimensional nanostructures for a broad range of applications. In this review, we provide an overview of various low temperature wet chemical synthetic approaches. In each fabrication method, we summarize the brief synthetic routes, microstructures, and the mechanism of anisotropic growth. In addition, the last section introduces various applications of one dimensional nanostructure arrays. This review provides the current status and prospects of the growth of one dimensional nanostructure arrays via wet chemical routes.", "author_names": [ "Joo Won Lee", "Young Min Kim", "Yun-Mo Sung" ], "corpus_id": 202212739, "doc_id": "202212739", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Wet chemical growth of semiconductor 1 D nanostructure arrays on conductive substrates", "venue": "", "year": 2019 } ]
Quick reference manual for silicon integrated circuit technology
[ { "abstract": "Physical Constants Physical Properties Basic Expressions Measurements Chemical Recipes Diffusion Ion Implantation Process Data IC Structures and Wafer Properties Conductivity of Diffused Layers Properties of p n Junctions Metal Semiconductor Junctions Surface Properties MOS Reliability Index.", "author_names": [ "W E Beadle", "Joseph C C Tsai", "R D Plummer" ], "corpus_id": 107414109, "doc_id": "107414109", "n_citations": 173, "n_key_citations": 2, "score": 1, "title": "Quick reference manual for silicon integrated circuit technology", "venue": "", "year": 1985 }, { "abstract": "", "author_names": [ "Arthur Kenneth Covington" ], "corpus_id": 93057365, "doc_id": "93057365", "n_citations": 27, "n_key_citations": 1, "score": 2, "title": "Quick Reference Manual for Silicon Integrated circuit Technology", "venue": "", "year": 1986 }, { "abstract": "", "author_names": [ "H A Kemhadjian" ], "corpus_id": 53787546, "doc_id": "53787546", "n_citations": 0, "n_key_citations": 0, "score": 2, "title": "Book review: Quick Reference Manual for Silicon Integrated Circuit Technology", "venue": "", "year": 1986 }, { "abstract": "Integrated silicon photonics is an exciting emerging technology, utilizing the high bandwidth and high timing resolution that optics provides in many applications. To maximize the benefits of these optical electrical systems, tight integration of the electronic and photonic components are necessary. In light of this need, we've developed a Cadence toolkit library written in VerilogA that simulates both the amplitude and phase of optical signals, as well as optical electrical interactions. The runtime is greatly improved by simulating the optical signal relative to a reference frequency, which is chosen to be close to the frequency range of interest. We have identified a set of fundamental photonic components, and described each at the physical level, such that the characteristics of a composite device will be created organically. We show that the simulated results match analytic solutions for simple devices like resonant ring filters and more complicated devices like single sideband modulators. Adding to this toolkit library, we then discuss devices that are required for handling more special cases, such as chromatic dispersion in the waveguide, and non ideal optoelectronic devices. Finally, we demonstrate simulations of complicated systems such as WDM links and Pound Drever Hall loops. This will allow designers to unify our photonic device designing and modeling environment with circuit and system level design, giving us greater insight on the trade offs that take place between the two realms.", "author_names": [ "Jonathan Leu" ], "corpus_id": 140082484, "doc_id": "140082484", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Integrated silicon photonic circuit simulation", "venue": "", "year": 2018 }, { "abstract": "In this paper, the design of a RF MEMS oscillator on a silicon ceramic composite substrate using a high Q Lamb wave resonator as frequency selective device is described. The MEMS resonator is designed on a 1.8 mm thick piezoelectric AlN layer, deposited on silicon using thin film processes. The finite element simulation results of the resonator structure are presented, and the derivation of the electrical equivalent circuit is described. The active part of the MEMS oscillator, which was laid out in a Pierce topology, has been integrated in an application specific integrated circuit fabricated in CMOS technology. Both, amplifying and frequency selective parts are hybrid integrated on a unique silicon ceramic composite substrate, which enables a very compact high quality module design with minimal parasitics. The MEMS oscillator serves as a technology demonstrator combining the advantages of microelectronic and microelectromechanical components towards a compact and power efficient hybrid technology, e.g. for mobile communications or wireless sensors.", "author_names": [ "Johannes Stegner", "Uwe Stehr", "Dmitry Podoskin", "Sebastian Gropp", "Michael Fischer", "Martin Hoffmann", "Jens Muller", "Matthias A Hein" ], "corpus_id": 28693719, "doc_id": "28693719", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Hybrid integrated RF MEMS based reference oscillator using a silicon ceramic composite substrate", "venue": "2016 German Microwave Conference (GeMiC)", "year": 2016 }, { "abstract": "Silicon Carbide is a promising wide bandgap material and gradually becoming the first choice of semiconductor for high density and high efficiency power electronics in medium voltage range (500 1500V) SiC has also excellent thermal conductivity and the devices fabricated with the material can operate at high temperature 400 0 C) Thus, a power electronic system built with SiC devices requires less cooling requirement and saves board space and cost. The high temperature applications of SiC material can also be extended to space exploration, oil and gas rigging, aerospace and geothermal energy systems for data acquisition, sensing and instrumentation and power conditioning and conversion. But the high temperature capability of SiC can only be utilized when the integrated circuits can be designed in SiC technology and high fidelity compact models of the semiconductor devices are a priori for reliable and high yielding integrated circuit design. The objective of this work is to develop industry standard compact models for SiC NMOS and PMOS devices. A widely used compact model used in silicon industry called BSIM3V3 is adopted as a foundation to build the model for SiC MOSFET. The models optimized with the builtin HSPICE BSIM3V3.3 were used for circuit design in one tape out but BSIM3V3 was found to be inadequate to model all of the characteristics of SiC MOSFET due to the presence of interface trapped charge. In the second tape out, the models for SiC NMOS and PMOS were optimized based on the built in HSPICE BSIM4V6.5 and a number of functioning circuits which have been published in reputed journal and conference were designed based on the models. Although BSIM4 is an enhanced version of BSIM3V3, it also could not model a few deviant SiC MOSFET characteristics such as body effect, soft saturation etc. The new model developed for SiC NMOS and PMOS based on BSIM4V7.0 is called BSIM4SIC and can model the entire range of device characteristics of the devices. The BSIM4SIC models are validated with a wide range of measured data and verified using the models in the simulation of numerous circuits such as op amp, comparator, linear regulator, reference and ADC/DAC.", "author_names": [ "Shamim Ahmed" ], "corpus_id": 114183324, "doc_id": "114183324", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Modeling and Validation of 4H SiC Low Voltage MOSFETs for Integrated Circuit Design", "venue": "", "year": 2017 }, { "abstract": "Abstract Manipulation of nanostructures is difficult, making it tough to fabricate nano device, let alone the fabrication of integrated nano sensor. In this paper, a monolithically integrated H 2 nano sensor array on a GaN honeycomb nanonetwork (GaN HN) are proposed and realized by combining GaN HN MBE growth with standard silicon micromachining techniques. For each H 2 nano sensor unit, a H 2 sensing element, a reference sensor, a micro heater, a resistive temperature detector (RTD) and the current circuit are integrated on a single chip. The H 2 sensing element Pt/GaN HN Schottky diode was well fabricated on the suspended GaN HN with 20 nm out of plane deformation and 0.0016 mm 1 curvature. An Au/GaN HN Schottky diode is proposed as the reference sensor and it is effective to reduce the output signal shift caused by ambient fluctuation to 20% Moreover, the micro heater on the free standing GaN HN has high heating efficiency with fast heating and cooling time (2.3 ms and 2.5 ms, respectively) In addition, the performance of H 2 nano sensor unit at room temperature and at 75 degC heated by the integrated micro heater with low power of 5.8 mW was recorded and discussed. At 75 degC, the response time t res and the recovery time t rec of the integrated H 2 sensor are significantly shortened by a factor of 3.", "author_names": [ "Aihua Zhong", "Takashi Sasaki", "Ping Fan", "Dong-ping Zhang", "Jingting Luo", "Kazuhiro Hane" ], "corpus_id": 103623451, "doc_id": "103623451", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Integrated H2 nano sensor array on GaN honeycomb nanonetwork fabricated by MEMS based technology", "venue": "", "year": 2018 }, { "abstract": "The last two decades has witnessed the CMOS processes and design techniques to develop and prosper with unprecedented speed. It has been widely employed in contemporary integrated circuit (IC) commercial products resulting in highly added value. Tremendous efforts have been devoted to extend and optimize the CMOS process and its application into future wireless communication systems. Meanwhile, the last twenty years have also seen the fast booming of the wireless communication technology typically characterized by the mobile communication technology, WLAN technology, WPAN technology, and etc. Nowadays, the spectral resource is getting increasingly scarce particularly over the frequency from 0.7 to 6 GHz, whether the employed frequency band is licensed or not. To combat this dilemma, the ultra wideband (UWB) technology emerges to provide a promising solution for short range wireless communication while using an unlicensed wide band in an overlay manner. Another trend of obtaining more spectrum is moving upwards to higher frequency bands. The WiFi Alliance has already developed a certification program of the 60 GHz band. On the other side, millimeter wave (mmWave) frequency bands such as 28 GHz, 38 GHz, and 71 GHz are likely to be licensed for next generation wireless communication networks. This new trend poses both a challenge and opportunity for the mmWave integrated circuits design. This thesis combines the state of the art IC and hardware technologies and design techniques to implement and propose the UWB and 5G prototyping systems. First of all, by giving a thorough analysis of a transmitted reference pulse cluster (TRPC) scheme and mathematical modeling, a TRPC UWB transceiver structure is proposed and its features and specifications are derived. Following that, the detailed design, fabrication and verification of the TRPC UWB transmitter front end and wideband voltage controlled oscillators (VCOs) in CMOS process is presented. The TRPC UWB transmitter demonstrates a starte of the art energy efficiency of 48 pJ/pulse. Secondly, a novel system architecture named distributed phased array based MIMO (DPA MIMO) is proposed as a solution to overcome design challenges for the future 5G cellular UE design. In addition, a prototyping design of on chip mmWave antenna with radiation efficiency enhancement is presented for the IEEE 802.11ad application. Furthermore, two wideband K band VCO prototypes based on two different topologies are designed and fabricated in a standard CMOS process. They both show good performance at center frequency of 22.3 and 26.1 GHz. Finally, two CMOS mmWave VCO prototypes working at the potential future 5G frequency bands are presented with measurement results.", "author_names": [ "Yiming Huo" ], "corpus_id": 116273303, "doc_id": "116273303", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Integrated silicon technology and hardware design techniques for ultra wideband and next generation wireless systems", "venue": "", "year": 2017 }, { "abstract": "(NOTE: Chapters 3 11 include an Introduction, Historical Development and Basic Concepts, Manufacturing Methods and Equipment, Measurement Methods, Models and Simulation, Limits and Future Trends in Technologies and Models, Summary of Key Ideas, References, and Problems. 1. Introduction and Historical Perspective. Introduction. Integrated Circuits and the Planar Process Key Inventions That Made It All Possible. Semiconductors. Semiconductor Devices. Semiconductor Circuit Families. Modern Scientific Discovery Experiments, Theory and Computer Simulation. The Plan for This Book. 2. Modern CMOS Technology. CMOS Process Flow. 3. Crystal Growth, Wafer Fabrication and Basic Properties of Silicon Wafers. 4. Semiconductor Manufacturing Clean Rooms, Wafer Cleaning and Gettering. 5. Lithography. 6. Thermal Oxidation and the Si/SiO2 Interface. 7. Dopant Diffusion. 8. Ion Implantation. 9. Thin Film Deposition. 10. Etching. 11. Backend Technology.", "author_names": [ "James D Plummer", "Michael D Deal", "Peter B Griffin" ], "corpus_id": 107363121, "doc_id": "107363121", "n_citations": 66, "n_key_citations": 11, "score": 0, "title": "Silicon VLSI Technology: Fundamentals, Practice, and Modeling", "venue": "", "year": 2020 }, { "abstract": "During post silicon validation, manufactured integrated circuits are extensively tested in actual system environments to detect design bugs. Bug localization involves identification of a bug trace (a sequence of inputs that activates and detects the bug) and a hardware design block where the bug is located. Existing bug localization practices during post silicon validation are mostly manual and ad hoc, and, hence, extremely expensive and time consuming. This is particularly true for subtle electrical bugs caused by unexpected interactions between a design and its electrical state. We present E QED, a new approach that automatically localizes electrical bugs during post silicon validation. Our results on the OpenSPARC T2, an open source 500 million transistor multicore chip design, demonstrate the effectiveness and practicality of E QED: starting with a failed post silicon test, in a few hours (9 h on average) we can automatically narrow the location of the bug to (the fan in logic cone of) a handful of candidate flip flops (18 flip flops on average for a design with ~1 Million flip flops) and also obtain the corresponding bug trace. The area impact of E QED is ~2.5% In contrast, determining this same information might take weeks (or even months) of mostly manual work using traditional approaches.", "author_names": [ "Eshan Singh", "Clark W Barrett", "Subhasish Mitra" ], "corpus_id": 5428674, "doc_id": "5428674", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "E QED: Electrical Bug Localization During Post silicon Validation Enabled by Quick Error Detection and Formal Methods", "venue": "CAV", "year": 2017 } ]
Microphone array structure
[ { "abstract": "Fluctuating pressure (p' of a large scale vortical structure generated in a semiconductor single wafer spin cleaner was detected by using microphone array. Twelve microphones were installed on the exhaust cover under the rotating disk of the cleaner with their interval of 7.5deg or 15deg. Power spectrum densities (PSD) of p' were compared with those of fluctuating velocity measured by PIV for various rotation angular velocities to identify fluctuations due to convection of the large scale vortical structure. Good agreement of PSDs indicates that the large scale structure could be detected by using microphone. Cross correlation of p' measured at different positions revealed that the large scale structure convected to the downstream in the rotational direction of the disk. The convection speed was about 12 of the angular velocity of the rotating disk. Number of the vortex in the large scale structure was also evaluated from the time series p' data. Time space contour map was made for p' based on the data measured at the different angular position, and showed periodical swept strip patterns. Presences of the strip patterns indicate the pressure disturbances were stably convected to the downstream. From this time space map, two dimensional Fourier transform efficiently extracted the number of vortices in the large scale structure.", "author_names": [ "Toshinori Kouchi", "Yu Miyoshi", "Yusuke Nakano", "Yasunori Nagata", "Shinichiro Yanase" ], "corpus_id": 114258648, "doc_id": "114258648", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Large scale vortical structure detection using microphone array in a semiconductor single wafer spin cleaner", "venue": "", "year": 2017 }, { "abstract": "PURPOSE: A microphone array structure, a method and an apparatus for forming a beam having a constant reflectivity and a method and an apparatus for estimating the direction of a sound source employing the same are provided to improve the recognition rate of the sound. CONSTITUTION: An apparatus for forming a beam having a constant reflectivity by employing the microphone array structure includes a microphone array(211) a beam forming unit(231) a filtering unit(251) and an adding unit(271) The microphone array(211) is provided with a first sub array(213) a second sub array(215) and a third sub array(215) The first sub array(213) is placed at a predetermined position of the flat plate. And, the second sub array(215) and the third sub array(217) are located at the position corresponding to the first to ith predetermined distance vertical to the extending line of the first sub array(213) and the central axis of the flat plate in response to the first to ith target frequencies of each sub array.", "author_names": [ "" ], "corpus_id": 125293606, "doc_id": "125293606", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Microphone array structure, method and apparatus for beamforming with constant directivity and method and apparatus for estimating direction of arrival, employing the same", "venue": "", "year": 2003 }, { "abstract": "Various microphone array geometries (e.g. linear, circular, square, cubic, spherical, etc. have been used to improve the positioning accuracy of sound source localization. However, whether these array structures are optimal for various specific localization scenarios is still a subject of debate. This paper addresses a microphone array optimization method for sound source localization based on TDOA (time difference of arrival) The geometric structure of the microphone array is established in parametric form. A triangulation method with TDOA was used to build the spatial sound source location model, which consists of a group of nonlinear multivariate equations. Through reasonable transformation, the nonlinear multivariate equations can be converted to a group of linear equations that can be approximately solved by the weighted least square method. Then, an optimization model based on particle swarm optimization (PSO) algorithm was constructed to optimize the geometric parameters of the microphone array under different localization scenarios combined with the spatial sound source localization model. In the optimization model, a reasonable fitness evaluation function is established which can comprehensively consider the positioning accuracy and robustness of the microphone array. In order to verify the array optimization method, two specific localization scenarios and two array optimization strategies for each localization scenario were constructed. The optimal array structure parameters were obtained through numerical iteration simulation. The localization performance of the optimal array structures obtained by the method proposed in this paper was compared with the optimal structures proposed in the literature as well as with random array structures. The simulation results show that the optimized array structure gave better positioning accuracy and robustness under both specific localization scenarios. The optimization model proposed could solve the problem of array geometric structure design based on TDOA and could achieve the customization of microphone array structures under different specific localization scenarios.", "author_names": [ "Haitao Liu", "Thia Kirubarajan", "Qian Xiao" ], "corpus_id": 203927238, "doc_id": "203927238", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Arbitrary Microphone Array Optimization Method Based on TDOA for Specific Localization Scenarios", "venue": "Sensors", "year": 2019 }, { "abstract": "When monitoring critical structures, fatigue fracture, deformations, holes and much more are cases of failure which must be detected at an early stage. Changes of the modal parameters (eigenfrequencies, attenuation ratios, and mode shapes) of the structure give information about the extent and the location of the deterioration. Conventional measurement methods (i.e. acceleration sensors, laser vibrometers, etc. for vibration analysis have the disadvantage that they can either \"detune\" the vibration modes due to their own weight and/or require a long measurement time due to punctual measurements. In contrast, the use of a suitable microphone array allows the high resolution acquisition of the entire surface vibration covered by the array. Thus, the modal parameters of interest are determined by measuring the pressure fluctuations in the near field of the structure. A commercial acoustic camera with 120 microphones (Fibonacci120, gfai tech GmbH) is used for this purpose. On the basis of artificially generated failure cases (load fracture, inhomogeneities, etc. on application oriented, large area structures, a method for the detection of failure cases using a microphone array is demonstrated.", "author_names": [ "Olaf Bolke", "J H Heimann", "Joaquin Garcia" ], "corpus_id": 204785643, "doc_id": "204785643", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Modal Analysis for damage detection in structures by non contact measurements with a commercial microphone array", "venue": "", "year": 2019 }, { "abstract": "", "author_names": [ "Shun-ichi Ohshima", "" ], "corpus_id": 65531651, "doc_id": "65531651", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "353 An analytical study of the insertion effect of the 2 D microphone array structure in the sound field", "venue": "", "year": 2005 }, { "abstract": "In order to get a better application of noise source identification by using microphone array,this paper studied the noise source identification performances of different microphone sub arrays.Based on the beamforming principle,we designed a mathematic computational model of planar arbitrary sub array and proposed the general sound source localization calculating equations of this model.Then,we deduced and analyzed the acoustic positioning algorithm formula respectively for two microphone array,three microphone array and four microphone array.The paper also showed the matrix solution of the three microphone array.The sound source recognition of different types of microphone sub structure was comparatively analyzed.Finally,we did a comparable acoustic source localization testing by establishing small microphone arrays which have the same size and were composed of different sub array forms.The final test results validate the reliability of the proposed model and algorithm.And the study obtains the conclusion that the microphone array structure composed of regular triangle sub array has better performance of noise source identification.", "author_names": [ "Wu Bobo" ], "corpus_id": 113567311, "doc_id": "113567311", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Study on the Noise Source Identification Properties of Microphone Sub array Structure", "venue": "", "year": 2013 }, { "abstract": "The microphone array arrangement structure compartment (100) (150) includes a convex curved configuration (LM) of the plurality of microphones (11,12,13,14) These microphones (11,12,13,14) including a first microphone (11) a first microphone (11) in the direction of the shaft (DRl) towards the mouth of the driver (170) (171) The microphone array arrangement structure (100) further includes a cover (30,31,33) the cover (30,31,33) for receiving the microphone (11, 12) and having a plurality of apertures (21, 22,23,24) Surface of the shell (30,31,33) forming a hole (21,22,23,24) shaped convex curve (LC) a microphone (11, 12) respectively corresponding to the aperture fixed to the inside of the cover (31, 33)", "author_names": [ "" ], "corpus_id": 126316387, "doc_id": "126316387", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The microphone array arrangement structure of the vehicle interior", "venue": "", "year": 2012 }, { "abstract": "", "author_names": [ "Markus Christoph" ], "corpus_id": 125196308, "doc_id": "125196308", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Spherical microphone array including a sound diffracting structure with cavity", "venue": "", "year": 2014 }, { "abstract": "", "author_names": [ "Michael Williams" ], "corpus_id": 106530811, "doc_id": "106530811", "n_citations": 4, "n_key_citations": 1, "score": 0, "title": "The Psychoacoustic Testing of the 3 D Multiformat Microphone Array Design and the Basic Isosceles Triangle Structure of the Array and the Loudspeaker Reproduction Configuration", "venue": "", "year": 2013 }, { "abstract": "We proposed a spatial coherence based PSD estimation and source separation technique in [1] using a 32 channel spherical microphone array. While the proposed spherical microphone based method exhibited a satisfactory performance in separating multiple sound sources in a reverberant environment, the use of a large number of microphones remains an issue for some practical considerations. In this paper, we investigate an alternative array structure to achieve spatial coherence based source separation using a planar microphone array. This method is particularly useful in separating a limited number of sound sources in a mixed acoustic scene. The simplified array structure we used here can easily be integrated with many commercial acoustical instruments such as smart home devices to achieve better speech enhancements.", "author_names": [ "Abdullah Fahim", "Prasanga N Samarasinghe", "Thushara Dheemantha Abhayapala", "Hanchi Chen" ], "corpus_id": 54435691, "doc_id": "54435691", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Planar Microphone Array for Spatial Coherence Based Source Separation", "venue": "2018 IEEE 20th International Workshop on Multimedia Signal Processing (MMSP)", "year": 2018 } ]
Tricritical behavior of two-dimensional intrinsic ferromagnetic
[ { "abstract": "\\mathrm{CrGeTe}}_{3} recently emerges as a new two dimensional (2D) ferromagnetic semiconductor that is promising for spintronic device applications. Unlike \\mathrm{CrSiTe}}_{3} whose magnetism can be understood using the 2D Ising model, \\mathrm{CrGeTe}}_{3} exhibits a smaller van der Waals gap and larger cleavage energy, which could lead to a transition of magnetic mechanism from 2D to 3D. To confirm this speculation, we investigate the critical behavior of \\mathrm{CrGeTe}}_{3} around the second order paramagnetic ferromagnetic phase transition. We obtain the critical exponents estimated by several common experimental techniques including the modified Arrott plot, Kouvel Fisher method, and critical isotherm analysis, which show that the magnetism of \\mathrm{CrGeTe}}_{3} follows the tricritical mean field model with the critical exponents \\ensuremath{\\beta} \\ensuremath{\\gamma} and \\ensuremath{\\delta} of $0.240\\ifmmode\\pm\\else\\textpm\\fi{}0.006$ $1.000\\ifmmode\\pm\\else\\textpm\\fi{}0.005$ and $5.070\\ifmmode\\pm\\else\\textpm\\fi{}0.006$ respectively, at the Curie temperature of 67.9 K. We therefore suggest that the magnetic phase transition from 2D to 3D for \\mathrm{CrGeTe}}_{3} should locate near a tricritical point. Our experiment provides a direct demonstration of the applicability of the tricritical mean field model to a 2D ferromagnetic semiconductor.", "author_names": [ "Guoming Lin", "Houlong L Zhuang", "X Luo", "B Liu", "F C Chen", "J Yan", "Y H Sun", "J Zhou", "W -J Lu", "P Tong", "Zhigao Sheng", "Zhe Qu", "W H Song", "X B Zhu", "Ya Ping Sun" ], "corpus_id": 118901536, "doc_id": "118901536", "n_citations": 69, "n_key_citations": 0, "score": 1, "title": "Tricritical behavior of the two dimensional intrinsically ferromagnetic semiconductor CrGeTe 3", "venue": "", "year": 2017 }, { "abstract": "CrI3, which belongs to a rare category of two dimensional (2D) ferromagnetic semiconductors, is of great interest for spintronic device applications. Unlike CrCl3 whose magnetism presents a 2D Heisenberg behavior, CrI3 exhibits a larger van der Waals gap, smaller cleavage energy, and stronger magnetic anisotropy which could lead to a 3D magnetic characteristic. Hence, we investigate the critical behavior of CrI3 in the vicinity of magnetic transition. We use the modified Arrott plot and Kouvel Fisher method, and conduct critical isotherm analysis to estimate the critical exponents near the ferromagnetic phase transition. This shows that the magnetism of CrI3 follows the crossover behavior of a 3D Ising model with mean field type interactions where the critical exponents \\b{eta} \\gamma} and \\delta} are 0.323, 0.835, and 3.585, respectively, at the Curie temperature of 64 K. We propose the crossover behavior can be attributed to the strong uniaxial anisotropy and inevitable interlayer coupling. Our experiment demonstrates the applicability of crossover behavior to a 2D ferromagnetic semiconductor.", "author_names": [ "Guoming Lin", "X Luo", "F C Chen", "J Yan", "J J Gao", "Y H Sun", "Wei Tong", "P Tong", "W -J Lu", "Zhigao Sheng", "W H Song", "X B Zhu", "Ya Ping Sun" ], "corpus_id": 119342947, "doc_id": "119342947", "n_citations": 34, "n_key_citations": 0, "score": 0, "title": "Critical behavior of two dimensional intrinsically ferromagnetic semiconductor CrI3", "venue": "", "year": 2018 }, { "abstract": "The low field magnetization M and susceptibility {chi} are reported for the two layered Ruddleson Popper phase SrO(La{sub 1{minus}x}Sr{sub x}MnO{sub 3}{sub 2} for x=0.4 (denoted La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7} with an in plane magnetic easy axis. As T approaches the Curie temperature T{sub C}=116 K) on cooling, where the metal insulator transition occurs in zero field, {chi} diverges as H{sup {minus}1/{delta}{sup {prime} with {delta}=21{plus_minus}5. Also, near an extrinsic Curie transition attributed to {approximately}0.1{percent} volume fraction of intergrowths at T{sup {asterisk}=2.47 T{sub C} M scales as (1{minus}T/T){sup {beta} with {beta}=0.25{plus_minus}0.02. These results can be understood within the context of two dimensional XY models, and provide some perspective of the layered manganites. {copyright} {ital 1998} {ital The American Physical Society}", "author_names": [ "Samuel D Bader" ], "corpus_id": 117848509, "doc_id": "117848509", "n_citations": 51, "n_key_citations": 0, "score": 0, "title": "Two Dimensional Intrinsic and Extrinsic Ferromagnetic Behavior of Layered La1.2Sr1.8Mn2O7 Single Crystals", "venue": "", "year": 1998 }, { "abstract": "A three dimensional breakdown behavior of the magnetic Bloch point domain wall (BP DW) propagation was investigated in a ferromagnetic nanowire with the variation of the external magnetic field by means of micromagnetic simulation. As magnetic field strength increases up to a threshold value, the BP DW velocity approaches a critical phase velocity of the spontaneously emitting spin wave (SW) where a Cherenkov type DW breakdown phenomenon is observed originating from an interaction between the spontaneously emitting SW and the BP DW. It is found that the velocity of the BP DW approaches a maximum value ~2000 m/s) due to the intrinsic reversal time of a BP spin texture. This suggests that although cylindrical ferromagnetic nanowires might be free from the two dimensional Walker breakdown phenomenon, there exists a Cherenkov type three dimensional breakdown behavior.", "author_names": [ "Xiao-Ping Ma", "Jiangshan Zheng", "Hong-Guang Piao", "Daekyu Kim", "Peter Fischer" ], "corpus_id": 225510785, "doc_id": "225510785", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Cherenkov type three dimensional breakdown behavior of the Bloch point domain wall motion in the cylindrical nanowire", "venue": "", "year": 2020 }, { "abstract": "In contrast to the current research on two dimensional (2D) materials, which is mainly focused on graphene and transition metal dichalcogenide like structures, studies on 2D transition metal oxides are rare. By using ab initio calculations along with Monte Carlo simulations and nonequilibrium Green's function method, we demonstrate that the transition metal oxide monolayer (ML) of Cr 2 O 3 is an ideal candidate for next generation spintronics applications. 2D Cr 2 O 3 has honeycomb kagome lattice, where the Dirac and strongly correlated fermions coexist around the Fermi level. Furthermore, the spin exchange coupling constant shows strong ferromagnetic (FM) interaction between Cr atoms. Cr 2 O 3 ML has a robust half metallic behavior with a large spin gap of ~3.9 eV and adequate Curie temperature. Interestingly, an intrinsic Ising FM characteristic is observed with a giant perpendicular magnetocrystalline anisotropy energy of ~0.9 meV. Most remarkably, nonequilibrium Green's function calculations reveal that the Cr 2 O 3 ML exhibits an excellent spin filtering effect.", "author_names": [ "Arqum Hashmi", "Kenta Nakanishi", "Muhammad Umar Farooq", "Tomoya Ono" ], "corpus_id": 226279495, "doc_id": "226279495", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Ising ferromagnetism and robust half metallicity in two dimensional honeycomb kagome Cr2O3 layer", "venue": "npj 2D Materials and Applications", "year": 2020 }, { "abstract": "Using first principles calculations based on density functional theory, we study the magnetic and electronic properties of hole doped two dimensional InSe. Our simulations reveal that although 2D InSe is intrinsically non magnetic, a stable ferromagnetic phase appears for a wide range of hole densities. Interestingly, hole doping not only induces spontaneous magnetization but also half metallicity, and hole doped InSe, presenting one conducting and one insulating spin channel, could be highly promising for next generation spintronic nanodevices. The possibility to induce hole doping and a subsequent ferromagnetic order by intrinsic and extrinsic defects was also investigated. We found that In vacancy creates spin polarized states close to the valence band and leads to a p type behavior. Similar to In vacancies, group V atoms replacing Se atoms", "author_names": [ "K Iordanidou", "Michel Houssa", "Joseph Kioseoglou", "Valeri V Afanas'ev", "Andre Stesmans", "Clas Persson" ], "corpus_id": 232118956, "doc_id": "232118956", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Hole doped two dimensional InSe for spintronic applications", "venue": "", "year": 2020 }, { "abstract": "We have investigated the critical behavior near the ferromagnetic transition of TlCo2S2 single crystals and the magnetic properties of Tl(Co0.95Ni0.05)2S2 by means of magnetization measurements. The obtained critical exponents b, g and d of TlCo2S2 could basically satisfy the scaling equations and are found very close to the prediction of the tricritical mean field theory. 5[Formula: see text] Ni doping drives the system to an antiferromagnetic ground state which is unstable to magnetic field, yielding metamagnetic transition. The possible existence of a tricritical point (TCP) in Tl(Co0.95Ni0.05)2S2 is also discussed.", "author_names": [ "Qianhui Mao", "Jinhu Yang", "Hangdong Wang", "Bin Chen", "Xiaodong Geng", "Mengyang Pan", "Minghu Fang" ], "corpus_id": 47013013, "doc_id": "47013013", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "From tricritical ferromagnetism to metamagnetism in quasi two dimensional Tl(Co1 x Ni x )2S2 (x 0, 0.05)", "venue": "Journal of physics. Condensed matter an Institute of Physics journal", "year": 2018 }, { "abstract": "Exploring two dimensional materials with both ferromagnetic and ferroelectric properties is scientifically interesting and of great technical importance to magnetoelectric nanodevices, which may overcome the volatility in traditional electrical control approaches. In this work, using first principles calculations, we design a multiferroic van der Waals heterostructure by combining the Dirac half metal MnCl3 and ferroelectric monolayer CuInP2S6. Through the short term voltage stimulation provided by an external electric field, we can switch the polarized state of the CuInP2S6 layer to achieve nonvolatile electrical control behavior in the Dirac half metal MnCl3. When MnCl3 is combined with CuInP2S6 in the P| state, the Dirac cones of the spin up channel are destroyed due to the interfacial charge transfer, but the half metal characteristic is preserved. By contrast, MnCl3 transforms into a magnetic semiconductor upon contact with CuInP2S6 in the P| state. More importantly, this transformation process does not depend on complex external mechanisms, and nonvolatile control can be achieved only through the intrinsic properties, which is related to the broken spatial inversion symmetry of ferroelectricity. Therefore, nonvolatile modulation of the electronic properties in the Dirac half metal MnCl3 can be achieved through magnetoelectric coupling with a ferroelectric CuInP2S6 layer, suggesting a promising platform for exploring high efficiency nanodevices and nonvolatile storage.", "author_names": [ "Zhengfu Li", "Baozeng Zhou" ], "corpus_id": 212926849, "doc_id": "212926849", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Theoretical investigation of nonvolatile electrical control behavior by ferroelectric polarization switching in two dimensional MnCl3/CuInP2S6 van der Waals heterostructures", "venue": "", "year": 2020 }, { "abstract": "Two dimensional (2D) materials with robust ferromagnetism have played a key role in realizing nextgeneration spin electronic devices, but many challenges remain, especially the lack of intrinsic ferromagnetic behavior in almost all 2D materials. Here, we highlight ultrathin Mn3O4 nanosheets as a new 2D ferromagnetic material with strong magnetocrystalline anisotropy. Magnetic measurements along the in plane and out of plane directions confirm that the out of plane direction is the easy axis. The 2D confined environment and Rashba type spin orbit coupling are thought to be responsible for the magnetocrystalline anisotropy. The robust ferromagnetism in 2D Mn3O4 nanosheets with magnetocrystalline anisotropy not only paves a new way for realizing the intrinsic ferromagnetic behavior in 2D materials but also provides a novel candidate for building next generation spin electronic devices.", "author_names": [ "Junchi Wu", "Xu Peng", "Yuqiao Guo", "Haowen Zhou", "Jiyin Zhao", "Ke-Qin Ruan", "Wangsheng Chu", "Changzheng Wu" ], "corpus_id": 125553780, "doc_id": "125553780", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Ultrathin nanosheets of Mn3O4: A new two dimensional ferromagnetic material with strong magnetocrystalline anisotropy", "venue": "", "year": 2018 }, { "abstract": "Two dimensional (2D) nanosheets have shown great potential for their applications in next generation nanoelectronic devices. However, developing 2D nanosheets for next generation spintronics has been blocked due to their lack of robust intrinsic ferromagnetic behavior. Here, we highlight the robust ferromagnetic behavior in a 2D inorganic graphene like structure. d FeOOH ultrathin nanosheets, as a new 2D material, exhibit an unprecedented high saturation magnetization value of 7.5 emu g 1 at room temperature, which is the highest value among graphene and graphene analogues. Atomic scale topochemical transformation ensures the formation of 2D d FeOOH ultrathin nanosheets from intermediate Fe(OH)2 nanosheets. Moreover, the d FeOOH ultrathin nanosheet is found to be a semiconductor with a direct band gap of 2.2 eV. Owing to the advantages of robust ferromagnetism in semiconductors, d FeOOH ultrathin nanosheets are promising candidates for the construction of next generation spintronics.", "author_names": [ "Pengzuo Chen", "Kun Xu", "Xiuling Li", "Yuqiao Guo", "Dan Zhou", "Jiyin Zhao", "Xiaojun Wu", "Changzheng Wu", "Yi Xie" ], "corpus_id": 97922343, "doc_id": "97922343", "n_citations": 66, "n_key_citations": 0, "score": 0, "title": "Ultrathin nanosheets of feroxyhyte: a new two dimensional material with robust ferromagnetic behavior", "venue": "", "year": 2014 } ]
Modeling of electron conduction in contact resistive random access memory devices as random telegraph noise
[ { "abstract": "The intense development and study of resistive random access memory (RRAM) devices has opened a new era in semiconductor memory manufacturing. Resistive switching and carrier conduction inside RRAM films have become critical issues in recent years. Electron trapping/detrapping behavior is observed and investigated in the proposed contact resistive random access memory (CR RAM) cell. Through the fitting of the space charge limiting current (SCLC) model, and analysis in terms of the random telegraph noise (RTN) model, the temperature dependence of resistance levels and the high temperature data retention behavior of the contact RRAM film are successfully and completely explained. Detail analyses of the electron capture and emission from the traps by forward and reverse read measurements provide further verifications for hopping conduction mechanism and current fluctuation discrepancies.", "author_names": [ "Yuan Heng Tseng", "Wen Chao Shen", "Chrong Jung Lin" ], "corpus_id": 33730381, "doc_id": "33730381", "n_citations": 35, "n_key_citations": 2, "score": 1, "title": "Modeling of electron conduction in contact resistive random access memory devices as random telegraph noise.", "venue": "Journal of applied physics", "year": 2012 }, { "abstract": "Single electron trapping/de trapping behavior is firstly observed and investigated in the contact resistive random access memory cell. By analyzing the random telegraph noise, the temperature dependency of resistance levels and the high temperature data retention behavior of the contact RRAM film are successfully explained. Detail analyses on the capture and emission of electrons in this contact RRAM cell provide further verifications for the proposed trap induced resistive switching model.", "author_names": [ "Yuan Heng Tseng", "Wen Chao Shen", "Chia-En Huang", "Chrong Jung Lin", "Ya-Chin King" ], "corpus_id": 26139126, "doc_id": "26139126", "n_citations": 45, "n_key_citations": 2, "score": 0, "title": "Electron trapping effect on the switching behavior of contact RRAM devices through random telegraph noise analysis", "venue": "2010 International Electron Devices Meeting", "year": 2010 }, { "abstract": "Variability in resistive random access memory cell has been one of the critical challenges for the development of high density RRAM arrays. While the sources of variability during resistive switching vary for different transition metal oxide films, the stochastic oxygen vacancy generation/recombination is generally believed to be the dominant cause. Through analyzing experimental data, a stochastic model which links the subsequent switching characteristics with its initial states of contact RRAM cells is established. By combining a conduction network model and the trap assisted tunneling mechanism, the impacts of concentration and distribution of intrinsic oxygen vacancies in RRAM dielectric film are demonstrated with Monte Carlo Simulation. The measurement data on contact RRAM arrays agree well with characteristics projected by the model based on the presence of randomly distributed intrinsic vacancies. A strong correlation between forming characteristics and initial states is verified, which links forming behaviors to preforming oxygen vacancies. This study provides a comprehensive understanding of variability sources in contact RRAM devices and a reset training scheme to reduce the variability behavior in the subsequent RRAM states.", "author_names": [ "Yun-Feng Kao", "Wei-Cheng Zhuang", "Chrong Jung Lin", "Ya-Chin King" ], "corpus_id": 51641487, "doc_id": "51641487", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "A Study of the Variability in Contact Resistive Random Access Memory by Stochastic Vacancy Model", "venue": "Nanoscale Research Letters", "year": 2018 }, { "abstract": "We investigated the low frequency noise (LFN) properties of the bipolar switching resistance random access memories (RRAMs) for the first time with amorphous TiOx based RRAM devices. The LFNs are proportional to 1/f for both high resistance (HRS) and low resistance states (LRS) The normalized noise in HRS is around an order of magnitude higher than that in LRS. The random telegraph noise (RTN) is observed only in HRS, which represents that the dominant trap causing the RTN becomes electrically inactive by being filled with electrons in LRS. The voltage dependence Si/I2 of shows that the noise can be used to elucidate the operation mechanism of RRAM devices.", "author_names": [ "Jung-kyu Lee", "Hu Young Jeong", "In-Tak Cho", "Jeong Yong Lee", "Sung-Yool Choi", "Hyuck-In Kwon", "Jongho Lee" ], "corpus_id": 6859683, "doc_id": "6859683", "n_citations": 19, "n_key_citations": 0, "score": 0, "title": "Conduction and Low Frequency Noise Analysis in \\hbox{Al}\\alpha\\hbox{ TiO}_{X}\\hbox{Al} Bipolar Switching Resistance Random Access Memory Devices", "venue": "IEEE Electron Device Letters", "year": 2010 }, { "abstract": "A new type of true random number generator, based on the random telegraph noise of a contact resistive random access memory device, is proposed in this letter. The random number generator consists of only a simple bias circuit plus a comparator, leading to small circuit area and low power consumption. By realizing this generator by the 65 nm complementary metal oxide semiconductor logic process, the occupied area can be as low as 45 mm2, demonstrating substantial saving in the circuit area.", "author_names": [ "Chien-Yuan Huang", "Wen Chao Shen", "Yuan Heng Tseng", "Ya-Chin King", "Chrong Jung Lin" ], "corpus_id": 7292794, "doc_id": "7292794", "n_citations": 103, "n_key_citations": 6, "score": 0, "title": "A Contact Resistive Random Access Memory Based True Random Number Generator", "venue": "IEEE Electron Device Letters", "year": 2012 }, { "abstract": "Low frequency noise (LFN) characteristics have been studied in polycrystalline TiOx based resistive random access memories (RRAMs) LFNs are proportional to 1/f in high resistance state (HRS) but those in low resistance state (LRS) are proportional to 1/f only in less than ~100 Hz. The normalized noise power in HRS is around three orders of magnitude higher than that in LRS. Bias dependence of 1/f noise shows that the current conduction mechanisms from noise measurements are consistent with those from the current voltage relationships in TiOx based unipolar RRAM devices.", "author_names": [ "Jung-kyu Lee", "In-Tak Cho", "Hyuck-In Kwon", "Cheol Seong Hwang", "Chan Hyeong Park", "Jongho Lee" ], "corpus_id": 41838764, "doc_id": "41838764", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Relationship Between Conduction Mechanism and Low Frequency Noise in Polycrystalline \\hbox{TiO}_{x} Based Resistive Switching Memory Devices", "venue": "IEEE Electron Device Letters", "year": 2012 }, { "abstract": "Resistive switching random access memory (RRAM) is widely considered as a disruptive technology. Despite tremendous efforts in theoretical modeling and physical analysis, details of how the conductive filament (CF) in metal oxide based filamentary RRAM devices is modified during normal device operations remain speculative, because direct experimental evidence at defect level has been missing. In this paper, a random telegraph signal based defect tracking technique (RDT) is developed for probing the location and movements of individual defects and their statistical spatial and energy characteristics in the CF of state of the art hafnium oxide RRAM devices. For the first time, the critical filament region of the CF is experimentally identified, which is located near, but not at, the bottom electrode with a length of nanometer scale. We demonstrate with the RDT technique that the modification of this key constriction region by defect movements can be observed and correlated with switching operation conditions, providing insight into the resistive switching mechanism.", "author_names": [ "Zheng Chai", "Jigang Ma", "Wei Dong Zhang", "Bogdan Govoreanu", "Jian Fu Zhang", "Zhigang Ji", "Malgorzata Jurczak" ], "corpus_id": 41491513, "doc_id": "41491513", "n_citations": 8, "n_key_citations": 2, "score": 0, "title": "Probing the Critical Region of Conductive Filament in Nanoscale HfO2 Resistive Switching Device by Random Telegraph Signals", "venue": "IEEE Transactions on Electron Devices", "year": 2017 }, { "abstract": "The ultimate sensitivity of any solid state device is limited by fluctuations. Fluctuations are manifestations of the thermal motion of matter and the discreteness of its structure which are also inherent ingredients during the resistive switching process of resistance random access memory (RRAM) devices. In quest for the role of fluctuations in different memory states and to develop resistive switching based nonvolatile memory devices, here we present our study on random telegraph noise (RTN) resistance fluctuations in Cu doped Ge0.3Se0.7 based RRAM cells. The influence of temperature and electric field on the RTN fluctuations is studied on different resistance states of the memory cells to reveal the dynamics of the underlying fluctuators. Our analysis indicates that the observed fluctuations could arise from thermally activated transpositions of Cu ions inside ionic or redox \"double site traps\" triggering fluctuations in the current transport through a filamentary conducting path. Giant RTN fluctuation.", "author_names": [ "Rohit Soni", "P M Meuffels", "Adrian Petraru", "Martin P Weides", "Carsten Kugeler", "Rainer Waser", "Hermann Kohlstedt" ], "corpus_id": 27277469, "doc_id": "27277469", "n_citations": 80, "n_key_citations": 3, "score": 0, "title": "Probing Cu doped Ge0.3Se0.7 based resistance switching memory devices with random telegraph noise", "venue": "", "year": 2010 }, { "abstract": "Nanoscale filament is the active area in oxygen vacancy type resistance random access memory (ReRAM) which is formed stochastically during electric test after being fabricated in a clean room. That is, the filament dimension cannot be controlled with a designed mask pattern. Here, we introduce a formula to describe the current cycle to cycle trajectories based on a stochastic differential equation (SDE) with microscopic structure parameters: filament dimension and oxygen vacancy concentration. Since ReRAM conduction follows hopping, the filament can be described by a random resistance network (RRN) The stochastic configuration of an RRN follows the Brownian motion, which is the key parameter in the diffusion of SDE. The formula provides a practically quantitative filament characterization method, which is verified by direct observation of the filament in actual devices. Based on the formula, we can predict ReRAM endurance with the given microscopic structure parameters.", "author_names": [ "Zhiqiang Wei", "Koji Eriguchi" ], "corpus_id": 44201242, "doc_id": "44201242", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Analytic Modeling for Nanoscale Resistive Filament Variation in ReRAM With Stochastic Differential Equation", "venue": "IEEE Transactions on Electron Devices", "year": 2017 }, { "abstract": "The root cause of degradation and failure in nanoscale logic and memory devices originates from discrete defects (traps) that are created in the ultra thin dielectrics during fabrication (process induced) and or voltage and temperature stress (stress induced) In order to probe the chemistry of every discrete trap in terms of its bond state, charge state, physical location, region of influence, activation (relaxation) energy and trap depth below conduction band, low frequency noise (LFN) based measurement and analysis is a good approach as the random telegraph noise (RTN) signals which form the characteristic behavior of every trap undergoing stochastic carrier capture and emission process contain a wealth of information on the defect energetics. With nanodevices still undergoing aggressive device scaling, the presence of a finite number of discrete defects in logic and memory devices makes it easier to collect RTN signals and analyze them in detail. This study presents an overall perspective to current developments in RTN based studies on logic and memory devices and their impact on the variability in performance metrics. This is by no means an exhaustive overview; however, the key advancements in RTN as an effective defect spectroscopy tool are highlighted.", "author_names": [ "Nagarajan Raghavan", "W H Liu", "R Thamankar", "Michel Bosman", "Kin Leong Pey" ], "corpus_id": 15747813, "doc_id": "15747813", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Understanding defect kinetics in ultra thin dielectric logic and memory devices using random telegraph noise analysis", "venue": "2015 IEEE 22nd International Symposium on the Physical and Failure Analysis of Integrated Circuits", "year": 2015 } ]
mechanism of chemically amplified resist
[ { "abstract": "The photo mask in lithographic process of semiconductor device has an important role to transfer the downsized target image to the wafer. Due to the development of information society, demand for semiconductor devices has been growing. In order to increase photo mask manufacturing throughput, the current density of electron beam (EB) has been getting higher. EB exposure increases the resist temperature on mask substrate inhomogeneous depending on its current density, shot size, writing order and etc. It is known that the resist sensitivity increases with irradiated resist temperature (heating effect) So, inhomogeneous temperature increase of resist on mask substrate disturbs precise pattern formation. However, the physical or chemical mechanism of heating effect has been still unknown. Here, we examined temperature dependence of acid generation process in chemically amplified resists (CARs) Poly(4 hydroxystyrene) (PHS) and poly(4 (tert butoxycarbonyl)oxy]styrene co 4 hydroxystyrene) (PTBSHS) were used as CAR resin. Monte Carlo simulation moving thermalized electron under the electric field between polymer radical cations were performed with changing the temperature. From the simulation, it was revealed that the energy increase of thermalized electron contributes to the acid yield by 0.038 /K. Quantification of the acid yields in resist films upon exposed to EB were performed with changing the temperature by titration method using Coumarin 6 (C6) as an acid sensitive dye. The acid yield increased by 0.14 /K in PHS film and 0.21 /K in PTBSHS film, respectively. Both values were higher than the simulation value (0.038 /K) Pulse radiolysis experiment was also performed to observe deprotonation of polymer radical cations at 298 and 343 K. The decay of dimer radical cation of PTBSHS became 1.6 times faster at 343 K than that at 298 K. From the results, it is suggested that the heating effect mainly caused by the temperature dependence of deprotonation rate from the radical cations of PTBSHS.", "author_names": [ "Yoshihiro Ikari", "N Maeda", "Akihiro Konda", "Takahiro Kozawa", "Toshihiko Tamura" ], "corpus_id": 216353581, "doc_id": "216353581", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Mechanism of resist heating effect in chemically amplified resist", "venue": "Advanced Lithography", "year": 2020 }, { "abstract": "EUV lithography utilizes photons with 91.6 eV energy to ionize resists, generate secondary electrons, and enable electron driven reactions that produce acid in chemically amplified photoresist. Efficiently using the available photons is of key importance. Unlike DUV lithography, where photons are selectively utilized by photoactive compounds, photons at 13.5nm wavelength ionize almost all materials. Nevertheless, specific elements have a significantly higher atomic photon absorption cross section at 91.6 eV. To increase photon absorption, sensitizer molecules, containing highly absorbing elements, can be added to photoresist formulations. These sensitizers have gained growing attention in recent years, showing significant sensitivity improvement. But there are few experimental evidences that the sensitivity improvement is due to the higher absorption only, as adding metals salts into the resist formulation can induce other mechanisms, like modification of the dissolution rate, potentially affecting patterning performance. In this work, we used different sensitizers in chemically amplified resist. We measured experimentally the absorption of EUV light, the acid yield, the dissolution rate and the patterning performance of the resists. Surprisingly, the absorption of EUV resist was decreased with addition of metal salt sensitizers. Nevertheless, the resist with sensitizer showed a higher acid yield. Sensitizer helps achieving higher PAG conversion to acid, notably due to an increase of the secondary electron generation. Patterning data confirm a significant sensitivity improvement, but at the cost of roughness degradation at high sensitizer loading. This can be explained by the chemical distribution of the sensitizer in the resist combined with a modification of the dissolution contrast, as observed by Dissolution Rate Monitor.", "author_names": [ "Yannick Vesters", "Jing Jiang", "Hiroki Yamamoto", "Danilo de Simone", "Takahiro Kozawa", "Stefan De Gendt", "Geert Vandenberghe" ], "corpus_id": 139156662, "doc_id": "139156662", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Sensitizers in EUV chemically amplified resist: mechanism of sensitivity improvement", "venue": "Advanced Lithography", "year": 2018 }, { "abstract": "Extreme ultraviolet (EUV) lithography is one of the most promising techniques in the semiconductor industry to enhance resolution, line edge roughness (LER) and sensitivity of chemically amplified resist (CAR) pattern. Post exposure bake (PEB) process, a major process in EUV lithography, has been studied by experimental approach, but they are confronted by time consuming tasks for massive combinatorial research. Also, theoretical models have been reported to explain fundamental mechanism of the process, but the single scale simulation studies show obvious limitations for accurate prediction of photo chemical reactions in photoresist (PR) matrix and the resulting morphology of line pattern. In order to settle the problem, a multiscale model (density functional theory (DFT) molecular dynamics (MD) finite difference method (FDM) integration) was developed to simulate chemical reactions including PAG dissociation, acid diffusion, and deprotection of photoresist in our previous study, which is based on two components system (PAG and PR) Herein, we propose the multiscale model for three molecular components consisting of PAG, PR, and photo decomposable quencher (PDQ) which is widely used for fine PR pattern fabrication by neutralizing acid in unexposed region of the resist. The newly constructed model reflects more realistic acid diffusion and chemical reactions on PEB process. This achievement will be helpful to identify critical design parameters and suggest optimized design materials in EUV lithography process.", "author_names": [ "Hyungwoo Lee", "Muyoung Kim", "Jung-Nim Moon", "Sungwook Park", "Byunghoon Lee", "Changyoung Jeong", "Maenghyo Cho" ], "corpus_id": 140459185, "doc_id": "140459185", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Multiscale approach for modeling EUV patterning of chemically amplified resist", "venue": "Advanced Lithography", "year": 2019 }, { "abstract": "The reaction mechanism of chemically amplified resist (CAR) after irradiation with ionizing radiation is important for developing extreme ultraviolet and electron beam lithography. The acid generation after the ionization is an essential reaction in CAR. In this study, the intermediate of the proton source of acid (a radical cation of the base polymer) in the presence of a photoacid generator (PAG) was investigated by the pulse radiolysis method. The deprotonation kinetics of the radical cation of poly(4 hydroxystyrene) (PHS) in solutions with and without PAG shows only a small difference. However, the yield of radical cations of poly(4 methoxystyrene) (PMOS) as a model of the resist with a protecting (releasing) group increases upon adding PAG. The formation of the ion pair between the PMOS radical cation and the dissociated anion with a lifetime of approximately 30 to 40 us is suggested. The lower acid yield in PMOS than in PHS film is also discussed in terms of the stability of the radical cation.", "author_names": [ "Kazumasa Okamoto", "Hiroki Yamamoto", "Takahiro Kozawa", "Ryoko Fujiyoshi", "Kikuo Umegaki" ], "corpus_id": 94932910, "doc_id": "94932910", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Pulse radiolysis study of polystyrene based polymers with added photoacid generators: Reaction mechanism of extreme ultraviolet and electron beam chemically amplified resist", "venue": "", "year": 2015 }, { "abstract": "The elevation of resist temperature during exposure to electron beam (EB) deforms the patterns of chemically amplified resists. The resist heating effect is a significant problem in mask production using a high current EB mask writer. However, its mechanism is still unknown. In this study, the effects of electron thermal energy on the sensitization process of chemically amplified EB resists were investigated using simulation on the basis of their sensitization mechanism. The decomposition yield of sensitizers increased with resist temperature. The effect of the increase of decomposition yield on the critical dimension (CD) was calculated on the basis of the reaction mechanism. When the exposure pattern width was set to the same as the half pitch (16 nm) the values of dCD/d T were 0.019, 0.013 and 0.010 nm K 1 for the sensitizer concentrations of 0.2, 0.3 and 0.4 (molecules) nm 3, respectively. dCD/d T was decreased by decreasing the exposure pattern width.", "author_names": [ "Takahiro Kozawa", "Takao Tamura" ], "corpus_id": 209978766, "doc_id": "209978766", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Theoretical study on effects of electron thermal energy on sensitization process of chemically amplified electron beam resists contribution to resist heating effect in electron beam mask writing", "venue": "Japanese Journal of Applied Physics", "year": 2019 }, { "abstract": "The acid diffusion in chemically amplified resists (CARs) which are a current standard resist for semiconductor device manufacturing is a significant concern in the development of highly resolving resists. Thus, high resolution CARs are reduced the number of the acid catalytic reaction per acid by high amount of acid quencher to suppressed acid diffusion blur for remaining low line width roughness (LWR) number. Non chemically amplified resists (non CARs) are generally lower LWR than CARs. However, non CARs are generally less sensitive to radiation than CARs due to lack of amplification mechanism. Recently, we proposed a negative type resist utilizing non CAR and CAR reactions on the same platform. This resist use radiation induced non catalitic reactions which are polarity change of onium decomposition and radical crosslinking of radiation decomposed monomers. And also, the resist uses an acid catalytic etherification utilizing diphenyl methanol derivative and aliphatic alcohol. These combination reaction by non CARs and CAR are expected to contribute the sensitivity improvement for high resolution resist. The synthesized resists were composed of triarylsulfonium cations as a polarity changer and radical generator, 2,2,2 trisubstituted acetophenone as a radical generator, triphenyl(4 vinylphenyl)stannane (TPSnSt) as an EUV absorption enhancer and a quencher, and 4 (2,4 Dimethoxyphenyl)hydroxymethyl]phenylmethacrylate (ARMA) as a polymer bound acid reactive unit. As the result, a 25 nm HP pattern could be obtained with 2.1 nm LWR and at 160 mC/cm2.", "author_names": [ "Satoshi Enomoto", "Kohei Machida", "Michiya Naito", "Takahiro Kozawa" ], "corpus_id": 204307302, "doc_id": "204307302", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Study of RLS trade off mitigation utilizing a novel negative chemically amplified resist for high resolution patterning", "venue": "Photomask Technology", "year": 2019 }, { "abstract": "The stochasticity in the sensitization processes of resist materials is a significant concern in the fine patterning. Such stochasticity results in the protected unit fluctuation in the case of a chemically amplified resist, which is a standard resist for photomask production. After development, the protected unit fluctuation comes to surface as line edge roughness, stochastic pinching, and stochastic bridging. In this study, the protected unit fluctuation after postexposure baking was investigated, assuming the fabrication of line and space patterns. The standard deviation of the number of protected units connected to a polymer molecule was calculated using a Monte Carlo method on the basis of the sensitization mechanism of chemically amplified electron beam (EB) resists. The dependences of the standard deviation on half pitch, sensitivity, sensitizer concentration, and exposure pattern width were clarified.", "author_names": [ "Takahiro Kozawa", "Takao Tamura" ], "corpus_id": 213076741, "doc_id": "213076741", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Theoretical study on protected unit fluctuation of chemically amplified resists used for photomask production by electron beam lithography", "venue": "", "year": 2020 }, { "abstract": "Abstract. Extreme ultraviolet (EUV) lithography utilizes photons with 92 eV energy to ionize resists, generate secondary electrons, and enable electron driven reactions that produce acid in chemically amplified photoresists. Efficiently using the available photons is of key importance. To increase photon absorption, sensitizer molecules, containing highly absorbing elements, can be added to photoresist formulations. These sensitizers have gained growing attention in recent years, showing significant sensitivity improvement. Aside from an increasing absorption, adding metal salts into the resist formulation can induce other mechanisms, like higher secondary electron generation or acid yield, or modification of the dissolution rate that also can affect patterning performance. In this work, we used different sensitizers in chemically amplified resists. We measured experimentally the absorption of EUV light, the acid yield, the photoelectron emission, the dissolution rate, and the patterning performance of the resists. Addition of a sensitizer raised the acid yield even though a decrease in film absorbance occurred, suggesting an apparent increase in chemically resonant secondary electrons. While patterning results confirm a significant sensitivity improvement, it was at the cost of roughness degradation at higher sensitizer loading. This is hypothesized by the chemical distribution of the sensitizer in the resist combined with a modification of the dissolution contrast, as observed by dissolution rate monitor measurements.", "author_names": [ "Yannick Vesters", "Jing Jiang", "Hiroki Yamamoto", "Danilo de Simone", "Takahiro Kozawa", "Stefan De Gendt", "Geert Vandenberghe" ], "corpus_id": 125940312, "doc_id": "125940312", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Sensitizers in extreme ultraviolet chemically amplified resists: mechanism of sensitivity improvement", "venue": "", "year": 2018 }, { "abstract": "The influence of degree of copolymerization of poly(styrene ran methyl methacrylate) [P(S MMA) on the deprotonation mechanism for EUV chemically amplified resists were investigated by pulse radiolysis, quantity of the acid yield, and density functional theory methods. The degradation of MMA unit occurs immediately before the hole transfer to the styrene unit in P(S MMA) in the low PS mole fraction 50 The hole transfer from MMA unit to styrene units occurred in the high PS mole fraction 70 It is assumed that the formation of styrene multimer (n 3) causes the hole transfer.", "author_names": [ "Yasuharu Tajima", "Kazumasa Okamoto", "Takahiro Kozawa", "Seiichi Tagawa", "Ryoko Fujiyoshi", "Takashi Sumiyoshi" ], "corpus_id": 122878320, "doc_id": "122878320", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Deprotonation mechanism of poly(styrene acrylate) based chemically amplified resist", "venue": "Advanced Lithography", "year": 2011 }, { "abstract": "As EUV approaches its insertion point into high volume manufacturing the semiconductor industry is increasingly focusing on photoresist performance. Recently metal containing resists have been proposed as alternatives to standard Chemically Amplified (CA) systems. Both approaches suffer from an incomplete knowledge of the EUV imaging mechanism. In particular the origin, number and fate of the secondary electrons believed to be active in the resist reactions is poorly understood. In this contribution we describe a study designed to try and characterize these processes and quantify the reactions that determine resist performances. We will describe experiments on a series of model CA systems doped with inorganic salts. Photoacid yields and relative rates of deprotection will be reported for metal salts that can be incorporated into polymer films at concentrations as high as 10 molal. In addition to comparing the relative performance at EUV we will also be characterizing the response at 248 nm and 100 KeV e beam. The results of these studies will be discussed in terms of the metal ion crossection, ionization potential and redox potential. In addition we will describe some unanticipated EUV reactivity of standard acid indicators that may impact the accepted electron yield/photospeed measurements that have been reported for EUV CA resists.", "author_names": [ "Gregory M Wallraff", "Hoa Dao Truong", "Martha I Sanchez", "Noel Arellano", "Alexander M Friz", "Wyatt A Thornley", "Oleg Kostko", "Daniel S Slaughter", "D Frank Ogletree" ], "corpus_id": 203015754, "doc_id": "203015754", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Model studies on the metal salt sensitization of chemically amplified photoresists (Conference Presentation)", "venue": "Advances in Patterning Materials and Processes XXXVI", "year": 2019 } ]
Motor soft start
[ { "abstract": "Ac motor as a motor soft starter auxiliary equipment, can be in ac motor no load or low load, automatic regulation input voltage motor, and may not affect the motor torque. Soft starter for the market, and is engaged in each industry production enterprise welcome, although at present in price, performance and so on have certain difficulty, but with semiconductor devices development of manufacturing technology, and can foresee in the near future, the soft starter certainly become a kind of improving the necessary depth ac motor application equipment. This paper taking three phase ac induction motor soft starter for research object, soft start analysis principle, design soft starter main circuit and circuit other system module, and application of Mat lab simulation, the simulation results indicated that soft start was used in motor start advantages.", "author_names": [ "Liu Shue", "Fu Chao" ], "corpus_id": 7416084, "doc_id": "7416084", "n_citations": 9, "n_key_citations": 0, "score": 1, "title": "Design and Simulation of Three phase AC Motor Soft start", "venue": "2013 Third International Conference on Intelligent System Design and Engineering Applications", "year": 2013 }, { "abstract": "In this paper two phase soft start control of three phase induction motor is proposed. The present three phase soft starter for induction motor is compared with that of proposed two phase soft starter on the basis of torque fluctuations, starting current demand and starting time of induction motor. A closed loop type of control for voltage and current is used for balanced operation during starting. This proposed topology is capable of minimizing starting current and starting torque fluctuations. Simulation results along with theoretical analysis on 2hp, 460V, four pole, three phase induction motor is presented.", "author_names": [ "Shrish Pandey", "S Bahadure", "Krishna Kanakgiri", "N M Singh" ], "corpus_id": 3092858, "doc_id": "3092858", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Two phase soft start control of three phase induction motor", "venue": "2016 IEEE 6th International Conference on Power Systems (ICPS)", "year": 2016 }, { "abstract": "Through the analysis of soft start ways which commonly used in medium voltage asynchronous motor, the soft start switching transformer topology of medium voltage asynchronous motor was given. It analyzed some key technologies of motor soft start, and gave the specific solutions. The problem of torque shock caused by the motor power factor angle and heavy start was analyzed especially. The main topological structures of the soft start devices about motor with large single power were given in the paper. Through the actual industrial applications of the soft start device, it showed that the device has reached the intended purposes, the device had a broad application prospect.", "author_names": [ "Wang Huan", "Su XiangRui", "Jin Guangzhe" ], "corpus_id": 6001568, "doc_id": "6001568", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "The study of switch transformer medium voltage asynchronous motor soft start device", "venue": "Proceedings of The 7th International Power Electronics and Motion Control Conference", "year": 2012 }, { "abstract": "Abstract In order to deal with the problems of large start current and low power factor that caused by threephase asynchronous motors start, a new integrative method of soft start and dynamic reactive power compensation is proposed. In this paper, the rule of power factor vs. speed in a three phase asynchronous motor is investigated and the reason of such rule is analyzed. Aiming at the large start current problem, soft start method based on auto transformer and magnetic control reactor (ATMCR) is invented. This method can further reduce start current from gird. Aiming at the low power factor problem, the method of thyristor switched capacitor (TSC) is used to dynamically compensate reactive power. Simulation and experimental results can prove that the integrative method can effectively deal with the problems of large start current and low power factor.", "author_names": [ "Chang Yu-fang", "Huang Wencong", "Yuan Youxin", "Wu Ming-hu", "Wang Su" ], "corpus_id": 61942330, "doc_id": "61942330", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Research on Reactive Power Compensation Issues in Process of Motor Soft Start", "venue": "", "year": 2013 }, { "abstract": "Soft start circuits with the main device of NTC thermistor,relay and mosfet are provided.The work principle and feature of three schemes are analyzed.The experiment results of each scheme are given.Test results show that the three proposed soft start circuits could inhibit the inrush current of DC motor start effectively.The application fields of the proposed soft start circuits are also given.", "author_names": [ "Li Dexin" ], "corpus_id": 64428361, "doc_id": "64428361", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Study of DC Motor Soft Start Circuit", "venue": "", "year": 2011 }, { "abstract": "According to the characteristics of the ac motor starting process, design a fuzzy soft start controller, realize constant current of ac motor soft start control. Using fuzzy soft start controller uses the two dimensional structure, current deviation and deviation change rate as input, Mining Mamdani inference method of fuzzy reasoning. The controller output to the adjustment of the thyristor trigger Angle. The results simulated by using Fuzzy toolbox to design. The results show that the fuzzy soft start controllers reasonable structure, simple rules, and easy to implement, motor soft start control to good effect. Copyright (c) 2014 IFSA Publishing, S. L.", "author_names": [ "Zheng Wang", "Qi Zhang" ], "corpus_id": 13826622, "doc_id": "13826622", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Research and Design of AC Motor Fuzzy Soft Start Controller", "venue": "", "year": 2014 }, { "abstract": "High power synchronous motor is difficult to start and unable to start and stop freely, so it must be long running. This will cause a lot of energy waste. In order to solve the problem, devices of self controlled soft start with variable frequency for high power synchronous motor are researched and developed. The TMS320F2812 DSP is used as main control chip to do all the control strategies in this soft start platform. This paper also gives a detailed method to do with the error signal of misleading zero crossing points of back EMF caused by inverter commutation, and describes the problem at the switch point from self impulse to back EMF zero crossing detection. It can get the rotor position without position sensor by accurate detection of motor back EMF zero crossing at medium and high speed. In the prototype platform, the motor can be soft started from standstill to rated speed stably and reliably.", "author_names": [ "Jin Guangzhe", "Zhou Changcheng", "Gao Qiang", "Xu Dian-guo" ], "corpus_id": 33958041, "doc_id": "33958041", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Research on system of self controlled soft start with variable frequency for synchronous motor", "venue": "Proceedings of The 7th International Power Electronics and Motion Control Conference", "year": 2012 }, { "abstract": "This paper presents a soft start circuit using the pulse width modulation (PWM) method. The motor is controlled by the dc chopper associated with a low cost PWM chip TL494. The design criteria are stated. The motor HC385MG is tested in experiment. The results illustrate that the circuit effectively reduces the inrush current at start up moment. The circuit also provides the speed adjustment and can be further implemented with the speed regulation and the over current protection.", "author_names": [ "Zongwang Lu", "Fuyan Sun" ], "corpus_id": 23395275, "doc_id": "23395275", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Soft start circuitry for DC motor", "venue": "2011 International Conference on Electrical and Control Engineering", "year": 2011 }, { "abstract": "This article in view of the question that the high power motor could not starting and stopping directly in the industry, proposed one kind of design based on PIC single chip high power motor soft start and intelligence protective devices, utilized real time measurement and control method with the feature of synchronous sampling electric current spurt value inverse time lag protection, according to the load situation four starting and protection control soft start ways of the under intelligent protection controller were designed. Intelligent soft starter design principles based on PIC single chip is articulated. The hardware circuit design, software flow design and test data analysis are given in details. By producing in Zibo Galaxy high technology development co. Ltd.,it shows that this smart soft starter has the characteristics which are flexible parameter setting, intuitive liquid crystal display, diverse starting way, precise current limiting protection, accurate protection of lack phase, low cost, collecting soft start and running protection with a body's protection controller, are suitable specially for the starting and control of high power motor, so the protector has broad application prospects. Index Terms motor, soft start, over load protection, PIC single chip", "author_names": [ "Lina Liu", "Jishun Jiang", "Liang Zhang" ], "corpus_id": 54731507, "doc_id": "54731507", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Research of Electric Motor Multi type Soft Start Control Mode Based on over load Protection", "venue": "", "year": 2011 }, { "abstract": "For the problem the AC induction motor direct starting current is too,of current closed loop electronic control fuzzy soft starter is designed,The soft starter can limit the starting current,in order to reduee the to the equipment.Between the feedback current and thyristor trigger angle since relation a fuzzy controller is presented to reduce the starting current.And improve the motor starting performance.Simulation results show that: the fuzzy soft start controller.Hasa easonable structure and simple rules easy to implement,effect of motor soft start control is good.", "author_names": [ "Zhang Liang" ], "corpus_id": 113287253, "doc_id": "113287253", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Simulation of Fuzzy Soft Start of Asynchronous Motor", "venue": "", "year": 2011 } ]
stacked die process
[ { "abstract": "Following the strong demand of high performance and miniaturized electronic devices with reduced process cycle time, the die attach film (DAF) has become a popular option for the die attach process of stacked die packages in the semiconductor assembly industry. The working temperature of a die attach process is crucial to assembly yield and package reliability. However, as the number of die stacks increases, the die attach process with DAF may encounter a technical bottleneck since the working area is gradually away from the heat source. In this study, the thermal effect from bottom heating of plural die stack structures was investigated through transient thermal analysis as well as temperature measurements in an actual stacked die process. It is clear from numerical and experimental results that as the number of dies in the die stack structure increases, the time required to reach a working temperature for DAF increases significantly.", "author_names": [ "Tsung-Yueh Tsai", "Hsiao-Chuan Chang", "Wei-Chung Li", "Chi-Ping Teng", "Yi-Shao Lai" ], "corpus_id": 31265941, "doc_id": "31265941", "n_citations": 2, "n_key_citations": 1, "score": 1, "title": "Working Temperature Characterizations for Die Attach Films in Stacked die Process", "venue": "2007 32nd IEEE/CPMT International Electronic Manufacturing Technology Symposium", "year": 2007 }, { "abstract": "Three dimensional (3 D) stacked die packaging can reduce cost and improve performance. It utilizes the oldest process, wire bonding, to connect chips with a large bond height difference (BHD) via deep cavity looping. This paper develops 3 D and 2 D finite element models of the process and validate them against experiments. The effects of the height difference between two bond points, reverse motion parameter, kink height parameter, and elliptic capillary traces on the process are studied. The simulations demonstrate that deep cavity looping produces greater deformation on kink II, a lower loop height, and more violent pulling on the wire than traditional looping. Optimized capillary trace parameters for traditional looping are not suitable for deep cavity looping; however, the trends in the effects of the parameters are the same. Elliptic capillary traces can change wire profiles significantly.", "author_names": [ "Fuliang Wang", "Yun Chen", "Lei Han" ], "corpus_id": 32495637, "doc_id": "32495637", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Modeling of Deep Cavity Looping Process on 3 D Stacked Die Package", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2013 }, { "abstract": "This paper examines the comprehensive effects of vapor pressure, hygroscopic swelling and thermal expansion on the reliability of stacked die package during soldering reflow by the finite element analysis. First, the moisture concentration distributions were obtained for preconditioning at MSL 1 as well as desorption at the reflow process. For the diffusion modeling, existing normalization approaches are only valid under constant temperature/humidity condition and cannot be extended to the reflow process which contains time varying thermal loading. In this study, the internal source approach was adopted to overcome the concentration discontinuity at material interfaces during solder reflow. A micromechanics based vapor pressure model was used to predict the vapor pressure field based on the moisture concentration results from the diffusion analysis. Second, a comprehensive nonlinear finite element model was proposed to integrate the effects of vapor pressure, thermo mechanical stress and hygro mechanical stress with consideration of the non uniform moisture distribution and the viscoelastic behavior of mold compound. The individual and integrated effects of vapor pressure, hygroscopic swelling and thermal expansion on warpage and stress distribution were investigated. Finally, a fracture mechanics based approach was used to study the thermal moisture impact on the delamination of the stacked die package. The transient variations of the strain energy release rate during soldering reflow due to the vapor hygro thermal mechanical stress were evaluated and compared under different crack lengths.", "author_names": [ "Jing Wang", "Seungbae Park" ], "corpus_id": 25549888, "doc_id": "25549888", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Non linear Finite Element Analysis on Stacked Die Package Subjected to Integrated Vapor Hygro Thermal Mechanical Stress", "venue": "2016 IEEE 66th Electronic Components and Technology Conference (ECTC)", "year": 2016 }, { "abstract": "In the present study the direct concentration approach (DCA) and the whole field vapor pressure model developed in Part I of this work (Xie et al. 2009 \"Direct Concentration Approach of Moisture Diffusion and Whole Field Vapor Pressure Modeling for Reflow Process: Part I Theory and Numerical Implementation, \" ASME J. Electron. Packag. 131, p. 031010) is applied to 3D ultrathin stacked die chip scale packages to investigate wafer level die attach film cohesive failures during the reflow process. Oversaturation, which refers to the film that absorbs more moisture when reflow process begins, is observed using the DCA. The modeling results suggest that the moisture transport and escape through the substrate during the reflow is responsible for the film rupture. A small reduction in substrate thickness could result in a significant decrease in moisture concentration and vapor pressure in bottom layer film and therefore reduce failure rate greatly. A slight improvement in reflow profile while still meeting specification allows a significant amount of moisture loss during the reflow; hence failure rate could also be reduced greatly. The mechanism of soft film rupture at reflow due to moisture is discussed in detail. The simulation results are consistent with the published experimental data.", "author_names": [ "Bin Xie", "Xuejun Fan", "Xunqing Shi", "Han Ding" ], "corpus_id": 108823009, "doc_id": "108823009", "n_citations": 40, "n_key_citations": 1, "score": 0, "title": "Direct Concentration Approach of Moisture Diffusion and Whole Field Vapor Pressure Modeling for Reflow Process Part II: Application to 3D Ultrathin Stacked Die Chip Scale Packages", "venue": "", "year": 2009 }, { "abstract": "As the demand is increasing for memory cards, portable computing systems, multiple chip packages (MCPs) and other applications that require thin integrated circuits (ICs) the wafer thinning for advanced packaging methods become more and more important. This paper gives an overview of the different industrial wafer thinning and dicing techniques, including dicing after grinding (DAG) dicing before grinding (DBG) laser cut after grinding (LAG) and laser stealth dicing before grinding (SDBG) The process capability for each process was compared, and the challenges encountered during thinning and dicing the wafer to be 25 um thickness are analyzed. Potential process issues have been investigated, including die strength and subsurface damage that is associated with these processes and mechanical properties, such as surface conditions and die warpage etc. Die strength test configurations and criteria are also included.", "author_names": [ "Renfu Zhang", "Hao Liu", "Bo Li", "Tetsukazu Sugiya" ], "corpus_id": 39252053, "doc_id": "39252053", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Ultra wafer thinning and dicing technology for stacked die packages", "venue": "2016 China Semiconductor Technology International Conference (CSTIC)", "year": 2016 }, { "abstract": "In the present study, the direct concentration approach (DCA) and the whole field vapor pressure model developed in Part I of this work (Xie et al. 2009 \"Direct Concentration Approach of Moisture Diffusion and Whole Field Vapor Pressure Modeling for Reflow Process: Part I Theory and Numerical Implementation,\" ASME J. Electron. Packag. 131, p. 031010) is applied to 3D ultrathin stacked die chip scale packages to investigate wafer level die attach film cohesive failures during the reflow process. Oversaturation, which refers to the film that absorbs more moisture when reflow process begins, is observed using the DCA. The modeling results suggest that the moisture transport and escape through the substrate during the reflow is responsible for the film rupture. A small reduction in substrate thickness could result in a significant decrease in moisture concentration and vapor pressure in bottom layer film and therefore reduce failure rate greatly. A slight improvement in reflow profile while still meeting specification allows a significant amount of moisture loss during the reflow; hence failure rate could also be reduced greatly. The mechanism of soft film rupture at reflow due to moisture is discussed in detail. The simulation results are consistent with the published experimental data. DOI: 10.1115/1.3144154", "author_names": [ "J Fan" ], "corpus_id": 38261941, "doc_id": "38261941", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Direct Concentration Approach of Moisture Diffusion and Whole Field Vapor Pressure Modeling for Reflow Process Part II Application to 3 D Ultrathin Stacked Die Chip Scale Packages", "venue": "", "year": 2009 }, { "abstract": "Quality control and failure analysis of IC packages require physical access to the die during destructive analysis. Successful analysis depends on the critical preservation of the original state of the die, bond wire, bond pad, and original failure sites during the package decapping process. The currently used acid and conventional plasma decapping techniques have their intrinsic limitations in certain analysis cases, for example 3D stacked die package with complex structures, HAST stressing that causes epoxy hardening, the use of epoxy refill materials and acid resistant epoxy molding compounds, the use of Cu and PdCu bond wires, preservation of original die and bond wire surface features, preservation of original failure sites and contaminants, etc. Such difficult cases with conventional decapping techniques often suffers from low analysis accuracy and low confidence level during root cause failure analysis, and consequently poses major threat to the quality assurance of the IC products. In order to overcome the limitations of conventional decapsulation techniques, a new generation decapsulation technique is developed with an atmospheric pressure Microwave Induced Plasma (MIP) As the MIP system operates at atmospheric pressure and the mean free path of ions at that pressure is extremely low, only isotropic high selectivity etching occurs by long lived oxygen radicals. Recipe and decapping process development is made to solve each of the challenging cases individually. As an ultimate evaluation on the capability of this MIP decapping technique, we deliberately combined multiple decapping difficulties into one single device: a 3D stacked die package that has deliberately introduced contamination and epoxy refill and went through HAST. It appears that the O2 only MIP afterglow decapsulation successfully preserves the deliberately introduced contamination sites in the 3D stacked die package. The unique capability of MIP decapsulation in facilitating accurate failure analysis and quality control is demonstrated.", "author_names": [ "J W Tang", "M R Curiel", "S L Furcone", "E G J Reinders", "C Th A Revenberg", "C I M Beenakker" ], "corpus_id": 25301850, "doc_id": "25301850", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Failure analysis of complex 3D stacked die IC packages using Microwave Induced Plasma afterglow decapsulation", "venue": "2015 IEEE 65th Electronic Components and Technology Conference (ECTC)", "year": 2015 }, { "abstract": "Portable consumer electronics have a tremendous demand of miniaturization, high density and high performance. 3D SIP is an efficient solution to meet this requirement. This paper had presented an innovative 3D package product configured with stacked die and cavity embedded substrate. Through hole via in the substrate provides the signal communication at a cost effective way. This structure satisfies the high standards for mobile products packaging by reducing the package size and cost and maintaining functionality. In this paper, some details on the design concepts of the structure are introduced. Then, since the geometric configuration of the bonding wire is unusual, the electrical performance of the wire bonds of the structure is predicted by HFSS. Though the wire bond is long, simulation results shows that it is still suitable for the speed circuits below 3GHz. On the other hand, the two step cavity effectively improves the isolation capability between different die. Moreover, the fabrication process of this structure is presented in detail to access the design. Finally, the functional test of the end products is performed and the end products work well.", "author_names": [ "Huiqin Xie", "James Li", "Jian Song", "Fengze Hou", "Xueping Guo", "Shuling Wang", "Yu Daquan", "Cao Liqiang", "Lixi Wan" ], "corpus_id": 43750452, "doc_id": "43750452", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "A 3D package design with cavity substrate and stacked die", "venue": "2013 14th International Conference on Electronic Packaging Technology", "year": 2013 }, { "abstract": "The copper based leadframe is practically proven effective in the thermal and reliability of a Quad Flat No Lead (QFN) three dimension (3D) stacked die semiconductor package. Reducing the copper thickness is understood to present various thermal and reliability failure mode and mechanisms, such as die cracking and delamination. However, no in depth study has been pursued to determine the capability of achieving the product requirements in terms of thermal and reliability in a 3D stacked die package. The drive towards a Die Free Package Cost (DFPC) reduction has led the authors to study the used of a thin leadframe in a QFN 3D stacked die. Hence, the work presents basis for the qualification of a thin leadframe design, and also to demonstrate the thermal and reliability performance. Finally, an extensive virtual thermal mechanical prototyping has to be achieved in order to understand the physics of materials during the assembly and reliability testing of a 3D stacked die package with a thin leadframe. This design rule was found to be developed in order to prevent a die crack occurrence between die and leadframe in the semiconductor package.", "author_names": [ "Samihah Abdullah", "Mohamad Faizal Abdullah", "Ahmad Kamal Ariffin", "Zalina Abdul Aziz", "Mariyam Jameelah Ghazali" ], "corpus_id": 9295372, "doc_id": "9295372", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Thermal Mechanical Analysis of a QFN Stacked Die Leadframe under Reflow Process", "venue": "", "year": 2008 }, { "abstract": "Process variations in integrated circuits have significant impact on their performance, leakage, and stability. This is particularly evident in large, regular, and dense structures such as DRAMs. DRAMs are built using minimized transistors with presumably uniform speed in an organized array structure. Process variation can introduce latency disparity among different memory arrays. With the proliferation of 3D stacking technology, DRAMs become a favorable choice for stacking on top of a multicore processor as a last level cache for large capacity, high bandwidth, and low power. Hence, variations in bank speed create a unique problem of nonuniform cache accesses in 3D space. In this paper, we investigate cache management techniques for tolerating process variation in a 3D DRAM stacked onto a multicore processor. We modeled the process variation in a four layer DRAM memory, including cell transistor, capacitor trench, and peripheral circuit, to characterize the latency and retention time variations among different banks. As a result, the notion of fast and slow banks from the core's standpoint is no longer associated with their physical distances with the banks. They are determined by the different bank latencies due to process variation. We develop cache migration schemes that utilize fast banks while limiting the cost due to migration. Our experiments show that there is a great performance benefit in exploiting fast memory banks through migration. On average, a variation aware management can improve the performance of a workload over the baseline (where one of the slowest bank speed is assumed for all banks) by 16.5 percent. We are also only 0.8 percent away in performance from an ideal memory where no process variation is present.", "author_names": [ "Bo Zhao", "Yu Du", "Jun Yang", "Youtao Zhang" ], "corpus_id": 24457252, "doc_id": "24457252", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Process Variation Aware Nonuniform Cache Management in a 3D Die Stacked Multicore Processor", "venue": "IEEE Transactions on Computers", "year": 2013 } ]
Light laser cutting wood mechanism
[ { "abstract": "The most frequently used mechanism of photon energy conversion in laser medicine is heating. Average heating of irradiated samples occurs with all methods of tissue destruction (cutting, vaporization, coagulation, ablation) At low light intensities the photochemical conversion of the energy absorbed by a photoacceptor prevails. This type of reaction is well known for specialized photoacceptors such as rhodopsin or chlorophyll. In medicine light absorption by non specialized photoacceptor molecules (that is, molecules that can absorb light at certain wavelengths, but that are not integral to specialized light reception organs) is used rather extensively. The absorbing molecule can transfer the energy to another molecule, and this activated molecule can then cause chemical reactions in the surrounding tissue. This type of reaction is successfully used in photodynamic therapy (PDT) of tumors. Alternatively, the absorbing molecule in a light activated form can take part in chemical reactions, as occurs in treatment of skin diseases with psoralens and UVA radiation (PUVA) Importantly, in both PDT and PUVA therapy the photoabsorbing molecules are artificially introduced into a tissue before irradiation. Irradiation of cells at certain wavelengths can also activate some of the native components. In this way specific biochemical reactions as well as whole cellular metabolism can be altered. This type of reaction is believed to form the basis for low power laser effects [1 41. One should note that light therapy methods based on photochemical conversion of photoabsorbing molecules are not laser specific methods [1] conventional sources generating the appropriate wavelength can also be used (as is done in PUVA and UV therapy) Laser sources are just handy tools providing many practical advantages (e.g. efficient fiber optic coupling to irradiate interior body parts, high monochromaticity and easy wavelength tunability, simplicity in use and electrical safety in the case of semiconductor lasers) It was shown that coherent effects in the light cells interaction occur at intensities 2x1015 W/m2 [1] Bear in mind that typical intensities used in low power laser therapy are in the range 1OlO2 W/m2. The successful use of light emitting diodes in low power laser therapy in the last years [5] proves that the coherence of light is of no importance in low power laser clinical effects. However, one should not forget about coherent laser light speckles which can cause local heating of inhomogeneous tissues [6] This possible mechanism forms a basis of laser thermotherapy [7] and supposedly can be taken into account at certain laser light parameters in low power laser therapy [8] when irradiating inhomogeneously absorbing tissues. For cell culture, the localized transient heating of absorbing chromophores is considered as one ofpossible primary mechanisms (Section 2.2) A photobiological reaction involves the absorption of a specific wavelength of light by the functioning photoreceptor (jhotoacceptor) molecule. To distinguish specialized photoreceptor molecules such as rhodopsin, phytochrome, bacteriorhodopsin and chlorophyll's from nonspecialized chromophores (molecules capable of absorbing the wavelength used for irradiation resulting in a photobiological response) below we will use the term photoacceptors to refer to the nonspecialized photoabsorbers. The photoacceptors take part in a metabolic reaction in a cell that is not connected with a light response. After absorbing the light of the wavelength used for irradiation this molecule assumes an electronically excited state from which primary molecular processes can lead to a measurable biological effect in certain circumstances. To work as a photoacceptor taking part in photobioregulation, this molecule must be part of a key structure that can regulate a metabolic pathway. Redox chains are example of this type of key structures which suit to these requirements. Possible photoacceptors (respiratory chain components) as well as chemical reactions occurring under illumination (primary reactions) or those following after the end of the irradiation (secondary reactions) are considered in Section 2:", "author_names": [ "Tiina I Karu" ], "corpus_id": 84643886, "doc_id": "84643886", "n_citations": 79, "n_key_citations": 0, "score": 1, "title": "Mechanisms of low power laser light action on cellular level", "venue": "European Conference on Biomedical Optics", "year": 2000 }, { "abstract": "A strip of a liquid crystal elastomer doped with a near infrared dye with one side crosslinked monodomain and the other crosslinked polydomain along the thickness behaves like a multifunctional photoactuator without the need for a support. A flat strip with two ends fixed on substrate surface forms a moving bump under laser scanning, which can be used as light fueled conveyor to transport an object. Cutting off and laser scanning the bump with two free ends makes a soft and flexible millimeter scale crawler that can not only move straight and climb an inclined surface, but also undergo light guided turning to right or left as a result of combined out of plane and in plane actuation. Based on the self shadowing mechanism, with one end of the strip fixed on substrate surface, it can execute a variety of autonomous arm like movements under constant laser illumination, such as bending unbending and twisting, depending on the laser incident angles with respect to the strip actuator.", "author_names": [ "Feijie Ge", "Rong Yang", "Xia Tong", "Franck Camerel", "Yuer Zhao" ], "corpus_id": 51702953, "doc_id": "51702953", "n_citations": 60, "n_key_citations": 0, "score": 0, "title": "A Multifunctional Dye doped Liquid Crystal Polymer Actuator: Light Guided Transportation, Turning in Locomotion, and Autonomous Motion.", "venue": "Angewandte Chemie", "year": 2018 }, { "abstract": "1. The Basic Principles. 1.1 The Cutting Process. 1.1.1 Cutting Parameters. 1.2 How Materials Respond to Laser Light. 1.3 How CO2 Lasers Work. 1.3.1 The Storage and Release of Energy from a CO2 Molecule. 1.3.2 Lasing. 1.3.3 The Role of Nitrogen. 1.3.4 The Role of Helium. 1.3.5 Gas Mixture Cooling. 1.3.6 Gas Recirculation. 1.3.7 A Summary of the Basic Energy Exchanges in a CO2 Laser. 1.4 Laser Modes. 1.4.1 Mode Types. 1.4.2 A Quick Guide to TEM Nomenclature. 1.4.3 The Effect of Laser Design on Mode and the Implications for Materials Processing. 2. Laser Cutting Steels. 2.1 Mild steels. 2.1.1 Introduction. 2.1.2 The Cutting Mechanism for Mild Steels. 2.1.3 Cutting Speeds and Cut Quality. 2.1.4 Cut Initiation and Termination. 2.1.5 Techniques to Avoid Unwanted Material Burning. 2.1.6 The Effect of Sheet Surface Finish on the Cutting Process. 2.1.7 The Importance of Axial Symmetry of the Energy Input to the Cutting Zone. 2.1.8 Pulsed Laser Cutting of Mild Steels. 2.2 Alloy Steels. 2.2.1 Introduction. 2.2.2 Stainless Steels. 2.2.3 Low Alloy Steels. 2.2.4 Silicon Iron. 2.2.5 Free Cutting Steels. 2.2.6 Carbon Steels. 3. Cutting Non ferrous Metals. 3.1 Introduction. 3.2 Titanium Alloys. 3.2.1 Laser Oxidation Cutting. 3.2.2 Laser Inert Gas Cutting. 3.3 Aluminium Alloys. 3.3.1 Introduction. 3.3.2 The Effect of Surface Condition on Cutting (Anodising etc. 3.3.3 Pulsed Laser Cutting. 3.3.4 Piercing a High Reflectivity Metal. 3.4 Nickel Alloys. 3.5 Copper Alloys. 3.6 General Comments. 4. Cutting Non metals. 4.1 Introduction. 4.1.1 Melt Shearing. 4.1.2 Vaporisation. 4.1.3 Chemical Degradation. 4.2 Polymers. 4.2.1 Cutting by Melt Shearing. 4.2.2 Cutting by Vaporisation. 4.2.3 Cutting by Chemical Degradation. 4.2.4 Cutting Speeds for Polymers. 4.2.5 Cut Speed Forecasting for Polymers Using a Standard Processing Curve. 4.3 Wood Based Products. 4.4 Ceramics and Glasses. 4.4.1 Ceramics. 4.4.2 Glasses. 4.5 Composites and Miscellaneous Materials. 4.5.1 Composite Materials. 4.5.2 Miscellaneous Materials. 5. Setting Up for Cutting. 5.1 Introduction. 5.2 Beam Alignment. 5.2.1 Introduction. 5.2.2 Taking a Beam Print. 5.2.3 Alignment by the Beam Print Method. 5.2.4 Alignment by use of a HeNe Laser. 5.3 Finding the Focus Position. 5.3.1 Introduction. 5.3.2 The Blue Flash Test. 5.3.3 The Drilling Test. 5.4 Nozzles and Nozzle Alignment. 5.4.1 General Comments. 5.4.2 Practical Considerations. 5.4.3 Nozzle Alignment. 5.4.4 The Gas Dynamics of Nozzles. 5.5 Jigging. 5.5.1 Methods of Supporting the Workpiece. 5.5.2 Laser Cut Supports. 5.5.3 Chutes. 5.5.4 Overlay Jigging for Flimsy Materials. 5.5.5 Clamps and Vices. 5.6 Tuning the Laser. 5.6.1 Fine Tuning. 5.6.2 Mode Prints. 5.6.3 Use of a Laser Beam Analyser. 5.6.4 Laser Alignment. 6. Troubleshooting. 6.1 Introduction and Checklist. 6.2 Notes on Checklist. 6.2.1 Nozzle Contamination. 6.2.2 Laser Power Level and Type. 6.2.3 Cutting Speed. 6.2.4 Cutting Gas Type, Pressure and/or Flow Rate. 6.2.5 Nozzle Material Standoff. 6.2.6 Nozzle Type, Condition and Alignment. 6.2.7 Material Specification. 6.2.8 Lens Type, Condition and Alignment. 6.2.9 Laser Mode Quality. 6.2.10 External Mirror Condition and Alignment. 7. Safety Guidelines. 7.1 Introduction. 7.2 Beam Exposure. 7.2.1 Skin Damage. 7.2.2 Eye Safety. 7.3 Fumes. 7.3.1 Metals. 7.3.2 Non metals. 7.4 Electrocution. 7.5 Fires. 8. Alternative Cutting Methods. 8.1 Nd:YAG Laser Cutting. 8.1.1 The Principle of Operation of Nd: YAG Lasers. 8.2 Plasma Arc Cutting. 8.3 Abrasive Water Jet Cutting. 8.3.1 Abrasive Free Fluid Jets. 8.4 Oxygen Flame Cutting. 8.5 A Summary of the Strengths and Weaknesses of Each Process Compared with CO2 Laser Cutting. 9. The Physics and Design of CO2 Lasers. 9.1 Introduction. 9.2 The Physics of CO2 Lasers. 9.2.1 The CO2 Energy Spectrum. 9.2.2 Interactions in a Pure CO2 Laser. 9.2.3 The Role of Nitrogen. 9.2.4 The Role of Helium. 9.2.5 The Energy Cycle of Mixed Gas CO2 Lasers. 9.2.6 Population Inversion. 9.2.7 Laser Modes and TEM Nomenclature. 9.3 Aspects of the Design of CO2 Lasers. 9.3.1 Introduction. 9.3.2 Methods of Exciting the Lasing Gas Mixture. 9.3.3 Methods of Cooling the Lasing Gas Mixture. 9.3.4 Designs of Optical Cavity. 10. Some Aspects of the Physics and Chemistry of Laser Cutting. 10.1 Introduction. 10.2 The Energy Balance in the Cut Zone and Its Relationship to the Efficiency of the Process. 10.2.1 The Effect of Decreasing the Material Thickness on Cutting Speeds. 10.2.2 The Limits on Material Thickness. 10.2.3 The Implications of the Energy Balance Argument to Changes in Laser Power. 10.3 The Role of Oxidation when Cutting Steels. 10.3.1 Mild Steel. 10.3.2 Stainless Steel. 10.4 Conductive Losses Experienced when Cutting Steels. 10.5 Notes on Reflected, Transmitted, Radiated and Convective Losses from the Cut Zone. 10.5.1 Reflected and Transmitted Losses. 10.5.2 Radiation and Convective Losses. 10.6 Notes on the Focusing Characteristics of CO2 Lasers. 10.6.1 Theoretical Focused Spot Size and Depth of Focus. 10.6.2 The Discrepancy Between Theory and Practice. 10.6.3 Concluding Comments. 11. Bibliography and Further Reading. 11.1 Conference Proceedings and Journals. 11.1.1 Conference Proceedings. 11.1.2 Journals. 11.2 Books. 11.3 Specific Papers. 11.3.1 General Reviews of Laser Processing and Cutting. 11.3.2 Cutting Metals. 11.3.3 Cutting Non metals. 11.3.4 Theoretical Analyses of the Cutting Process. 11.3.5 CO2 Lasers. 11.3.6 Nozzle Design and Gas Dynamics. 11.3.7 Laser Beam Analysis. 11.3.8 Alternative Cutting Methods. 11.4 Miscellaneous References. 11.5 Further reading update for the second edition of this book.", "author_names": [ "John Powell" ], "corpus_id": 136532356, "doc_id": "136532356", "n_citations": 46, "n_key_citations": 1, "score": 0, "title": "CO[2] laser cutting", "venue": "", "year": 1993 }, { "abstract": "Abstract The mechanisms of melt ejection and striation formation in continuous wave laser cutting of mild steel are discussed. Melt ejection from the cutting front is shown to be a cyclic phenomenon. Striation formation is strongly affected by the oscillatory characteristic of the thin liquid film on the cutting front during melt ejection, together with the oxidation and heat transfer process. Cutting speed determines whether the liquid film will rupture or generate waves on the cutting front. Theoretical explanations are given according to the instability theory of a thin liquid film in a high velocity gas jet and the diffusion controlled oxidation theory. Striation frequency and depth are predicted according to the above theories. Experimental investigations were carried out and the results are consistent with the calculations. The better understanding has shed light on further investigations and optimal process development.", "author_names": [ "Kai Chen", "Y Lawrence Yao" ], "corpus_id": 17006989, "doc_id": "17006989", "n_citations": 45, "n_key_citations": 4, "score": 0, "title": "Striation Formation and Melt Removal in the Laser Cutting Process", "venue": "", "year": 1999 }, { "abstract": "Abstract The present study examines the combined effects of chemical reactions taking place between a gas jet and molten metal, the cooling effect of the jet and the evaporation of metal, during a CO 2 laser cutting process. A laminar boundary layer approach was used to develop a theoretical model for the oxygen gas jet laser cutting mechanism. An experiment was carried out to monitor the keyhole formation using a video recorder and detect the light emitted from the entrance and exist surfaces of the workpiece using a fibre optic probe during the cutting process. The experimental study was extended to employ two different workpiece materials (stainless steel and mild steel) at two thicknesses, and varying oxygen assisting gas pressures. It is found that the theoretical model developed in the present study is valid for a cutting speed of about 30 mm s 1 and all jet velocities up to sonic, since the effect of shock is excluded in the model.", "author_names": [ "Bekir Sami Yilbas", "Ahmet Z Sahin" ], "corpus_id": 122745884, "doc_id": "122745884", "n_citations": 39, "n_key_citations": 0, "score": 0, "title": "Oxygen assisted laser cutting mechanism a laminar boundary layer approach including the combustion process", "venue": "", "year": 1995 }, { "abstract": "Abstract The objective of this study is to experimentally investigate the cutting mechanisms of polycrystalline diamond compacts (PDC) using two different lasers: (a) a near infrared Nd:YAG laser (Neodymium doped Yttrium Aluminum Garnet) of 1064 nm wavelength and 100 ms pulse width; and (b) a green light KTP (Potassium Titanyl Phosphate)/Nd:YAG laser of 532 nm wavelength and 120 ns pulse width. To realize the objective, the study applies polishing, lapping and etching processes to the cut surfaces of the PDC samples. It further observes and analyzes the processed cut surfaces with scanning electron microscopy (SEM) and Raman spectroscopy. A discussion is provided to reveal the underlying physics of the laser cutting mechanisms, and a conclusion is drawn based on the outcomes from the experimental investigation and the discussion.", "author_names": [ "G F Zhang", "Bi Zhang", "Zhaohui Deng", "J F Chen" ], "corpus_id": 120483196, "doc_id": "120483196", "n_citations": 40, "n_key_citations": 4, "score": 0, "title": "An Experimental Study on Laser Cutting Mechanisms of Polycrystalline Diamond Compacts", "venue": "", "year": 2007 }, { "abstract": "Abstract The relationship between fiber dislocations and fiber cutting during the enzymatic hydrolysis of lignin free fibers was investigated. Dislocations are morphological changes in the microfibril direction of cellulose. It was hypothesized that enzymatic activity is concentrated at dislocation sites, resulting in fiber cutting. Bleached softwood kraft pulp was analyzed during enzymatic hydrolysis (Novozynme 188 and Celluclast 1.5L) to confirm fiber cutting and explore its relationship with dislocation sites via microscopy, fiber length, and sugar determination. Results reveal that fibers were quickly cut through during enzymatic hydrolysis, resulting in shorter fiber fragments during the initial 60% of hydrolysis. Polarized light microscopy images show a relationship between dislocations and fiber cutting during enzymatic hydrolysis. Images show fibers partially cut at dislocation sites, and that there are no dislocations on cut fibers after 6 h hydrolysis. PLM and FQA data revealed that there were about seven major dislocations per fiber and each fiber was cut through about 6, and 10 times after 4 and 6 h of enzymatic hydrolysis, respectively. In combination, this data strongly implicates dislocation sites as the location of fiber cutting.", "author_names": [ "Kim Gail Clarke", "Xinping Li", "Kecheng Li" ], "corpus_id": 85203000, "doc_id": "85203000", "n_citations": 37, "n_key_citations": 2, "score": 0, "title": "The mechanism of fiber cutting during enzymatic hydrolysis of wood biomass", "venue": "", "year": 2011 }, { "abstract": "Optical coherence imaging can measure hole depth in real time >20 kHz) during laser drilling without being blinded by intense machining light or incoherent plasma emissions. Rapid measurement of etch rate and stochastic melt relaxation makes these images useful for process development and quality control in a variety of materials including metals, semiconductors, and dielectrics. The ability to image through the ablation crater in materials transparent to imaging light allows the guidance of blind hole cutting even with limited a priori knowledge of the sample. Significant improvement in hole depth accuracy with the application of manual feedback from this imaging has been previously demonstrated [P. J. L. Webster et al. Opt. Lett. 35, 646 (2010) However, the large quantity of raw data and computing overhead are obstacles for the application of coherent imaging as a truly automatic feedback mechanism. Additionally, the high performance components of coherent imaging systems designed for their traditio.", "author_names": [ "Paul J L Webster", "Logan G Wright", "Kevin D Mortimer", "Ben Y C Leung", "Joe X Z Yu", "James M Fraser" ], "corpus_id": 55331011, "doc_id": "55331011", "n_citations": 31, "n_key_citations": 1, "score": 0, "title": "Automatic real time guidance of laser machining with inline coherent imaging", "venue": "", "year": 2011 }, { "abstract": "Abstract An experimental investigation of carbon fiber reinforced plastic (CFRP) composite processing with a high power pulsed fiber laser was conducted. A CFRP plate was irradiated with laser light from a pulsed fiber laser with an average power of 125 W, a repetition rate of 167 kHz and a pulse width of 10 ns. The wavelength of the laser light was 1064 nm. A galvanometer scanner was used as the processing head for high speed scanning of the pulsed laser light. A hatching distance was introduced, and the processing rates were measured according to the parameters of hatching distance and scanning speed. The walls at the grooves irradiated by laser light were observed using scanning electron microscopy (SEM) and cross sectional profiles of the processed CFRP were measured using confocal laser scanning microscopy (CLSM) The kerf width was measured by optical microscopy observation of the CFRP sample surface processed by laser irradiation. The growth mechanism of the kerf and heat affected zone (HAZ) structures was investigated based on cross sectional SEM micrographs of the kerfs. The optimal hatching distance for the target groove depth is discussed, together with the importance of the hatching distance for high speed and high quality processing of CFRP. The results indicate that adjustment of the hatching distance and the scanning speed are important for obtaining both good cutting speed and quality.", "author_names": [ "Kunitoshi Takahashi", "Masahiro Tsukamoto", "Shin-ichiro Masuno", "Yuji Sato", "Hidetsugu Yoshida", "Koji Tsubakimoto", "Hisanori Fujita", "N Miyanaga", "Masayuki Fujita", "Hidenari Ogata" ], "corpus_id": 136637833, "doc_id": "136637833", "n_citations": 30, "n_key_citations": 0, "score": 0, "title": "Influence of laser scanning conditions on CFRP processing with a pulsed fiber laser", "venue": "", "year": 2015 }, { "abstract": "Abstract BaGd 2 ZnO 5 Dy 3+ Yb 3+ was successfully synthesized by the sol gel method. The crystal structure and morphology of the samples were characterized by X ray powder diffraction (XRD) and scanning electron microscope. Under 3 W 971 nm near infrared laser excitation, the near infrared emission of phosphors was intense. The dependence of the up conversion emission intensities of the phosphors on the working power of laser diode was obtained as an evidence for the energy transfer from Yb 3+ to Dy 3+ In comparison, under excitation of 354 nm light, the near infrared quantum cutting for the BaGd 2 ZnO 5 Dy 3+ Yb 3+ samples is proved by the emission spectra. The corresponding quantum cutting mechanisms are discussed through the energy level. The maximum quantum efficiency calculated approaches 158.0% This study has the prospect to be applied in silicon based solar cells to promote the conversion efficiency.", "author_names": [ "Yanmin Yang", "Lin-lin Liu", "Shuzhen Cai", "Fuyun Jiao", "Chao Mi", "Xian-yuan Su", "Jiao Zhang", "Fang Yu", "Xiaodong Li", "Ziqiang Li" ], "corpus_id": 95979182, "doc_id": "95979182", "n_citations": 25, "n_key_citations": 0, "score": 0, "title": "Up conversion luminescence and near infrared quantum cutting in Dy3+ Yb3+ co doped BaGd2ZnO5 nanocrystal", "venue": "", "year": 2014 } ]
4 bit flash adc
[ { "abstract": "This study describes the highly digital 4 bit 200 MS flash analogue to digital converter (ADC) whose major part can be digitally synthesised thus achieving low power, reducing the time to market and is scalable with technology. The comparators used in the ADC consist of complementary metal oxide semiconductor (CMOS) based inverter and NAND NOR as standard cells. The complete flash ADC is designed in 180 nm CMOS technology with 1.8 V supply with the power consumption of 4.51 mW. The signal to noise and distortion ratio, signal to noise ratio and spurious free dynamic range are equal to 23.3, 25.2 and 30.1 dB. It provides an effective number of bits equal to 3.5. The differential non linearity (DNL) of this ADC is 0.25 LSB and integral non linearity (INL) is 0.6 LSB.", "author_names": [ "Ashima Gupta", "Anil Singh", "Alpana Agarwal" ], "corpus_id": 58015442, "doc_id": "58015442", "n_citations": 6, "n_key_citations": 2, "score": 1, "title": "Highly digital voltage scalable 4 bit flash ADC", "venue": "IET Circuits Devices Syst.", "year": 2019 }, { "abstract": "This article describes a design of 4 bit Flash analogue digital converter (ADC) for Ultra Wideband (UWB) sensor systems. The ADC cell structure was designed and fabricated in 0.35 um SiGe BiCMOS technology. Proposed ADC cell achieves up to 1.1 Gs/s with maximum input signal range 1.6 Vpp at 1 MHz. The power consumption of the designed cell is 30 mA from 3.3 V power supply. For basic measurement, the ADC has been directly wires bonded to PCB. The basic measurements are represented by time domain and input output ADC characteristics. The ADC was primarily designed as a test structure for M sequence UWB SoC radar.", "author_names": [ "Miroslav Sokol", "Pavol Galajda", "Stanislav Slovak", "Martin Pecovsky" ], "corpus_id": 184465229, "doc_id": "184465229", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Design of 4 bit Flash ADC Cell for UWB Sensor Systems", "venue": "2019 29th International Conference Radioelektronika (RADIOELEKTRONIKA)", "year": 2019 }, { "abstract": "In this paper, a standard cell low power 4 bit flash analog to digital converter (ADC) is proposed. The converter utilizes comparators created using only logic gates for converting analog input signals to digital values. This novel flash architecture consists of several CMOS gates with inputs connected to a common input node or to one of the supply lines. Depending on the relationship between the input signal and a given gate's threshold voltage, the output will either be `0' or `1' The comparator is followed by an encoder to convert the thermometer code to binary code. Low power consumption is achieved by switching off the unused parallel voltage comparators. The proposed ADC was implemented at the transistor level in a 180nm CMOS technology with a 1.8 V supply voltage and was simulated using Cadence Spectre simulator. Simulation results show that for the same speed, this ADC provides about 70% power reduction compared to a previously proposed design.", "author_names": [ "Marcel Siadjine Njinowa", "Hung Tien Bui", "Francois R Boyer" ], "corpus_id": 26381575, "doc_id": "26381575", "n_citations": 32, "n_key_citations": 1, "score": 0, "title": "Design of low power 4 bit flash ADC based on standard cells", "venue": "2013 IEEE 11th International New Circuits and Systems Conference (NEWCAS)", "year": 2013 }, { "abstract": "Among all the ADC architectures, Flash ADCs are the most preferred ones. High speed operation is the main reason for selecting Flash ADC. Applications which require high speed conversion in mixed mode signal processing needs Flash ADC. In order to have high speed Flash ADC, the design of comparators is the main task. Since comparators in Flash ADC are power hungry components, we should design each compactor in such a way that overall power consumption should be less. Here we have designed a dynamic comparator consuming low power of 0.169uW. Then we have implemented encoder block using 2:1 MUX. Using these components we have implemented 4 bit Flash ADC which is having power dissipation of 7.2394mW and delay of 29.792ns. The design is implemented in Mentor Graphics tool using 180nm Technology.", "author_names": [ "H Patil", "M R Raghavendra" ], "corpus_id": 9948320, "doc_id": "9948320", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Low power dynamic comparator for 4 bit Flash ADC", "venue": "2016 IEEE International Conference on Computational Intelligence and Computing Research (ICCIC)", "year": 2016 }, { "abstract": "In this work a high speed flash ADC based on threshold invert quantization (TIQ) comparator has been proposed. Unlike conventional ADC resistive ladder and comparator bank has been replaced by TIQ comparator which compares the varying input with in built switching potential, 2n 1 number of TIQ requires with different switching for n bit ADC. 4 bit flash ADC has been implemented with static and dynamic TIQ; Different threshold of static TIQ is obtained by scaling the width of PMOS and NMOS individually while in dynamic TIQ input to each inverting stage acts as body voltage decide threshold voltage dynamically, threshold of TIQ is function of individual MOS width and body potential. Cadence Spectre based simulation result show that static TIQ should preferred for low power and dynamic TIQ for high speed.", "author_names": [ "Abhishek Kumar" ], "corpus_id": 214131615, "doc_id": "214131615", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design of 4 Bit Flash ADC Using Static and Dynamic TIQ Comparator", "venue": "", "year": 2019 }, { "abstract": "Nowadays, there is the highest use of converters in the industries. The degradation of power consumption by these converters has great importance. This paper represents a new method to decrease the power consumption of the flash type analog to digital converter with 250 nm CMOS technology by using frequency which is of 1MHz. Flash type ADC requires 2 1 Comparator and its power supply voltage 2.5V. The proposed design of ADC using the Quantum Voltage Comparator eliminates the resistor ladder circuit and improves linearity of ADC. For the encoding process, the Pseudo logic encoder has been used and it provides higher data conversion rate and maintain low power consumption. The proposed 4 bit flash ADC paper having 876 MSPS speed and optimized power consumption by using the pseudo logic encoder and Quantum Voltage Comparator.", "author_names": [ "Sarang S Karale", "Dhanashri M Hogale" ], "corpus_id": 198234426, "doc_id": "198234426", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design of 876 MSPS, 2.5v, 250nm, 4 Bit Flash ADC using Quantum Voltage Comparator and Pseudo Logic Encoder", "venue": "", "year": 2019 }, { "abstract": "In this paper design of low power 4 bit Flash ADC for high frequency applications is presented. The power consumption of the Flash ADC in this work has been reduced in two phase. In the first phase a low power dynamic comparator has been designed which consumes 329.332 uW power. In the second phase a low power Fat tree encoder has been designed. The proposed encoder design uses reduced number of gates than the conventional design. As a result the average power dissipation of the encoder block is 43.6uw. The above mentioned Flash ADC is designed using CMOS 90nm Technology in Cadence tool. The proposed design has a power consumption of 5.1096 mW at IV power supply and at a sampling frequency of 1GHz.", "author_names": [ "David Sundararaj Shylu", "S Radha", "P Sam Paul", "Parakati Sarah Sudeepa" ], "corpus_id": 211056953, "doc_id": "211056953", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design of low power 4 bit Flash ADC in 90nm CMOS Process", "venue": "2019 2nd International Conference on Signal Processing and Communication (ICSPC)", "year": 2019 }, { "abstract": "This paper presents the design of 4 bit flash type analog to digital converter implemented in 22 nm FD SOI technology with 0.8 V supply voltage. This block is part of original sub ranging ADC whose working principle is based on the assumption that sub ADC and sub DAC exhibit high linearity while they nominal resolutions remain relatively low. The linearity of the presented flash ADC has to be as high as in case of 8 bit converter. Thus, the most challenging task was to design comparator with resolution of 1.5 mV. This goal was reached owing to ability offered by the FD SOI process to trim transistor's threshold voltage by means of modulating the back gate polarization. The resulting sampling rate is 500 Ms/s.", "author_names": [ "Zbigniew Jaworski" ], "corpus_id": 199489569, "doc_id": "199489569", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Highly Linear 4 bit Flash ADC Implemented in 22 nm FD SOI Process", "venue": "2019 MIXDES 26th International Conference \"Mixed Design of Integrated Circuits and Systems\"", "year": 2019 }, { "abstract": "This paper presents a 35 GS/s, 4 bit flash ADC DAC with active data and clock distribution trees. At mm wave clock frequencies, skew due to mismatch in the clock and data distribution paths is a significant challenge for both flash and time interleaved converter architectures. A full rate front end track and hold amplifier (THA) may be used to reduce the effect of skew. However, it is found that the THA output must then be distributed to the comparators with a bandwidth greater than the sampling frequency in order to preserve the flat regions of the track and hold waveform. Instead, if the data and clock distribution have very low skew, the THA can be omitted thus obviating the associated nonlinearities and resulting in improved performance. In this work, a tree of fully symmetric and linear BiCMOS buffers, called a ldquodata treerdquo, distributes the input to the comparator bank with a measured 3 dB bandwidth of 16 GHz. The data tree is integrated into a complete 4 bit ADC including a full rate input THA that can be disabled and a 4 bit thermometer code DAC for testing purposes. The chip occupies 2.5 mm times 3.2 mm including pads and is implemented in 0.18 mum SiGe BiCMOS technology. The ADC consumes 4.5 W from a 3.3 V supply while the DAC operates from a 5 V supply and consumes 0.5 W. The ADC has 3.7 ENOB with a 3 dB effective resolution bandwidth of 8 GHz and a full scale differential input range of 0.24 Vpp. With the THA enabled, the performance degrades rapidly beyond 8 GHz to less than 1 bit, but with the THA disabled, the ENOB remains better than 3 bits for inputs up to 11 GHz with an SFDR of better than 26 dB.", "author_names": [ "Shahriar Shahramian", "Sorin P Voinigescu", "Anthony Chan Carusone" ], "corpus_id": 25676067, "doc_id": "25676067", "n_citations": 69, "n_key_citations": 7, "score": 0, "title": "A 35 GS/s, 4 Bit Flash ADC With Active Data and Clock Distribution Trees", "venue": "IEEE Journal of Solid State Circuits", "year": 2009 }, { "abstract": "A 4 bit noninterleaved flash ADC implemented in 0.18 mum digital CMOS achieves a sampling rate of 4 GS/s. A 32 mum by 32 mum, on chip differential inductor in each comparator extends the sampling rate without an increase in power consumption. A combination of DAC trimming and comparator redundancy reduces the measured DNL and INL to less than 0.15 LSB and 0.24 LSB, respectively. The measured ENOB with a 100 MHz full power input is 3.84 bits and 3.48 bits, at 3 GS/s and 4GS/s, respectively. The ADC achieves a bit error rate of less than 10 11 at 4 GS/s.", "author_names": [ "Sunghyun Park", "Yorgos Palaskas", "Michael P Flynn" ], "corpus_id": 12637070, "doc_id": "12637070", "n_citations": 104, "n_key_citations": 1, "score": 0, "title": "A 4 GS/s 4 bit Flash ADC in 0.18 \\mu{\\hbox {m} CMOS", "venue": "IEEE Journal of Solid State Circuits", "year": 2007 } ]
Encyclopedia of Materials: Science and Technology
[ { "abstract": "Subject areas: Functional Phenomena. Electrical and thermal transport in normal solids. Physics and application of superconductors. Lattice properties and thermodynamics. Metal gas reactions and electrochemistry. Magnetism and electronic properties and bulk solids. Hard and soft magnetic materials, manufacturing and applications. Magneto optical and optical recording. Magnetic recording magnetic fluids. Physical properties of thin films and artificial multilayers. Optical and dielectric phenomena. Fundamental Core Theory. Fundamentals of materials science. Amorphous materials. Nuclear materials and irradiation effects. Biomedical and dental materials. Natural products and biomimetics. Carbon. Wood and paper. Characterization of materials. Surfaces: structure and properties. Miscellaneous. Structural Materials. Metal extraction, melting and refining. Metal processing. Structure, transformations and properties, light metals. Structure, transformations and properties, ferrous metals. Ceramic processing. Structure, transformations, properties in ceramics. Composites: MMC, CMC, PMC. Applications: aerospace automotive, sports, other. Applications: building. Modeling: atomic, microscale, large scale. Materials selection, life cycle costs, environmental tradeoffs, etc. Corrosion. Structural Phenomena. Elasticity residual stress. Brittle fracture. Plastic deformation in static loading. Microscopic models of plasticity. Deformation and damage under cyclic load. Creep, strength and fatigue at elevated temperature. Mechanical properties of surfaces and in micro dimensions. Deformation related processing. Mechanical testing and nondestructive inspection. Polymers and Materials Chemistry. Crystalline polymers. Glassy amorphous and liquid crystalline polymers. Conducting and semiconducting polymers and organics. Elastomers, networks and gels. Block copolymers. Industrial polymerization chemistry. New synthesis methods for speciality polymers. Polymer processing. Inorganic materials chemistry. Organic/inorganic hybrid materials. Self assembling materials chemistry. Liquid crystals. Functional Materials. Physics and chemistry of semiconductors. Semiconducting devices. Defects in semiconductors. Evaluation of semiconductors. Crystal growth. Epitaxial growth. Semiconductor processing and IC fabrication. Nonlinear optical materials. Electroceramics. Packaging.", "author_names": [ "K H Jurgen Buschow" ], "corpus_id": 136363962, "doc_id": "136363962", "n_citations": 1113, "n_key_citations": 1, "score": 1, "title": "Encyclopedia of materials science and technology", "venue": "", "year": 2001 }, { "abstract": "", "author_names": [ "Greg H Parker" ], "corpus_id": 178727084, "doc_id": "178727084", "n_citations": 148, "n_key_citations": 14, "score": 0, "title": "Encyclopedia of Materials: Science and Technology", "venue": "", "year": 2001 }, { "abstract": "", "author_names": [ "Mark A Miodownik" ], "corpus_id": 136148043, "doc_id": "136148043", "n_citations": 192, "n_key_citations": 14, "score": 0, "title": "Encyclopedia of materials: science and technology", "venue": "", "year": 2001 }, { "abstract": "", "author_names": [ "Michael Mclean" ], "corpus_id": 137462261, "doc_id": "137462261", "n_citations": 46, "n_key_citations": 1, "score": 0, "title": "Encyclopedia of materials science and technology", "venue": "", "year": 1986 }, { "abstract": "", "author_names": [ "Subhash Mahajan" ], "corpus_id": 203008390, "doc_id": "203008390", "n_citations": 47, "n_key_citations": 1, "score": 0, "title": "Encyclopedia of Materials: Science and Technology", "venue": "", "year": 2001 }, { "abstract": "", "author_names": [ "K Goovaerts", "Paul Lambrechts", "Jan De Munck", "Lars Bergmans", "Bart Van Meerbeek" ], "corpus_id": 198005407, "doc_id": "198005407", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Encyclopedia of materials: science and technology", "venue": "", "year": 2002 }, { "abstract": "", "author_names": [ "John F Nye" ], "corpus_id": 185732132, "doc_id": "185732132", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Encyclopedia of Materials: Science and technology", "venue": "", "year": 2001 }, { "abstract": "", "author_names": [ "Zdenek P Bazant", "Kurt Heinz Juergen Buschow" ], "corpus_id": 135971951, "doc_id": "135971951", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Creep of concrete: Encyclopedia of Materials: Science and Technology", "venue": "", "year": 2001 }, { "abstract": "", "author_names": [ "" ], "corpus_id": 138699650, "doc_id": "138699650", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Encyclopedia of Materials: Science and Technology Magnets: Sintered", "venue": "", "year": 2001 }, { "abstract": "", "author_names": [ "Wesley Roth Burghardt" ], "corpus_id": 139475461, "doc_id": "139475461", "n_citations": 1, "n_key_citations": 1, "score": 0, "title": "Rheology of Liquid Crystalline Polymers: Encyclopedia of Materials Science and Technology", "venue": "", "year": 2001 } ]
High purcell factor generation of
[ { "abstract": "On chip single photon sources are key components for integrated photonic quantum technologies. Semiconductor quantum dots can exhibit near ideal single photon emission, but this can be significantly degraded in on chip geometries owing to nearby etched surfaces. A long proposed solution to improve the indistinguishablility is to use the Purcell effect to reduce the radiative lifetime. However, until now only modest Purcell enhancements have been observed. Here we use pulsed resonant excitation to eliminate slow relaxation paths, revealing a highly Purcell shortened radiative lifetime (22.7 ps) in a waveguide coupled quantum dot photonic crystal cavity system. This leads to near lifetime limited single photon emission that retains high indistinguishablility (93.9% on a timescale in which 20 photons may be emitted. Nearly background free pulsed resonance fluorescence is achieved under p pulse excitation, enabling demonstration of an on chip, on demand single photon source with very high potential repetition rates.Exploiting both pulsed resonant excitation and a large Purcell enhancement, a single quantum dot coupled to a photonic crystal nanostructure can deterministically produce highly indistinguishable single photons for on chip quantum optical applications.", "author_names": [ "F Liu", "Alistair J Brash", "J O'hara", "L M P Martins", "Catherine L Phillips", "R J Coles", "B Royall", "Edmund Clarke", "Christopher Bentham", "Nikola Prtljaga", "I E Itskevich", "Luke R Wilson", "M S Skolnick", "A M Fox" ], "corpus_id": 205568107, "doc_id": "205568107", "n_citations": 103, "n_key_citations": 2, "score": 1, "title": "High Purcell factor generation of indistinguishable on chip single photons", "venue": "Nature Nanotechnology", "year": 2018 }, { "abstract": "An outstanding goal in quantum optics and scalable photonic quantum technology is to develop a source that each time emits one and only one entangled photon pair with simultaneously high entanglement fidelity, extraction efficiency, and photon indistinguishability. By coherent two photon excitation of a single InGaAs quantum dot coupled to a circular Bragg grating bull's eye cavity with a broadband high Purcell factor of up to 11.3, we generate entangled photon pairs with a state fidelity of 0.90(1) pair generation rate of 0.59(1) pair extraction efficiency of 0.62(6) and photon indistinguishability of 0.90(1) simultaneously. Our work will open up many applications in high efficiency multiphoton experiments and solid state quantum repeaters.", "author_names": [ "Hui Wang", "Hai Hu", "T H Chung", "Jian Qin", "Xiaoxia Yang", "J-P Li", "R-Z Liu", "Han-Sen Zhong", "Y -M He", "Xing Ding", "Y -H Deng", "Qing Dai", "Yongheng Huo", "Sven Hofling", "Chao-Yang Lu", "Jian-Wei Pan" ], "corpus_id": 84836268, "doc_id": "84836268", "n_citations": 109, "n_key_citations": 2, "score": 0, "title": "On Demand Semiconductor Source of Entangled Photons Which Simultaneously Has High Fidelity, Efficiency, and Indistinguishability.", "venue": "Physical review letters", "year": 2019 }, { "abstract": "The nitrogen vacancy (NV) center in diamond has an optically addressable, highly coherent spin. However, an NV center even in high quality single crystalline material is a very poor source of single photons: extraction out of the high index diamond is inefficient, the emission of coherent photons represents just a few per cent of the total emission, and the decay time is large. In principle, all three problems can be addressed with a resonant microcavity. In practice, it has proved difficult to implement this concept: photonic engineering hinges on nano fabrication yet it is notoriously difficult to process diamond without degrading the NV centers. We present here a microcavity scheme which uses minimally processed diamond, thereby preserving the high quality of the starting material, and a tunable microcavity platform. We demonstrate a clear change in the lifetime for multiple individual NV centers on tuning both the cavity frequency and anti node position, a Purcell effect. The overall Purcell factor $F_{\\rm P}=2.0$ translates to a Purcell factor for the zero phonon line (ZPL) of $F_{\\rm P}\\rm ZPL}\\sim30$ and an increase in the ZPL emission probability from \\sim 3 to \\sim 46 By making a step change in the NV's optical properties in a deterministic way, these results pave the way for much enhanced spin photon and spin spin entanglement rates.", "author_names": [ "Daniel Riedel", "Immo Sollner", "Brendan J Shields", "Sebastian Starosielec", "Patrick Appel", "Elke Neu", "Patrick Maletinsky", "Richard John Warburton" ], "corpus_id": 119078971, "doc_id": "119078971", "n_citations": 96, "n_key_citations": 4, "score": 0, "title": "Deterministic enhancement of coherent photon generation from a nitrogen vacancy center in ultrapure diamond", "venue": "", "year": 2017 }, { "abstract": "We theoretically demonstrate high quality(Q) factor micropillar cavities at 1.55 mm wavelength based on Si/SiO(2) InP hybrid structure. An adiabatic design in distributed Bragg reflectors (DBRs) improves Q factor for upto 3 orders of magnitude, while reducing the diameter to sub micrometer. A moderate Q factor of ~3000 and a Purcell factor of ~200 are realized by only 2 taper segments and fewer conventional DBR pairs, enabling single photon generation at GHz rate. As the taper segment number is increased, Q factor can be boosted to ~10(5) 10(6) enabling coherent exchange between the emitter and the optical mode at 1.55 mm, which is applicable in quantum information networks.", "author_names": [ "Haizhi Song", "Kazuya Takemoto", "Toshiyuki Miyazawa", "Motomu Takatsu", "Satoshi Iwamoto", "Mitsuru Ekawa", "Tsuyoshi Yamamoto", "Yasuhiko Arakawa" ], "corpus_id": 28628437, "doc_id": "28628437", "n_citations": 8, "n_key_citations": 3, "score": 0, "title": "High quality factor Si/SiO(2) InP hybrid micropillar cavities with submicrometer diameter for 1.55 mm telecommunication band.", "venue": "Optics express", "year": 2015 }, { "abstract": "This work presents the design and optimization of a cascade nano laser using CH3NH3PbI3 perovskite. Due to increasing threshold gain with decreasing device size and high Auger losses, the use of perovskite as the active medium in the cascade nano laser was proposed, as the material possesses a high emission rate in the visible wavelength region, with relative ease of device fabrication. By optimizing the thickness of the perovskite, its width, and the thickness of the silica used, photonic and plasmonic modes were created, which were further considered to permit the generation of lasing, using their respective Purcell factors. The pump wavelength considered was 400 nm, with the laser emission then at 537 nm. For suitability of plasmonic lasing, a Purcell factor FP of 1.22 is reported here, with no possibility for photonic lasing due to its FP value being less than 1 in this design. However, mode crossing effects were observed in the plasmonic mode at l 400 nm for two designs: at a silica thickness of 27.5 nm with perovskite thickness and width of 100 and 300 nm, respectively, and at a silica thickness of 30 nm with perovskite thickness and width of 95 and 300 nm, respectively. These mode crossing effects can be further analyzed to use these devices in the design of potential new sensor systems, mainly for gas and chemical sensing, exploiting the refractive index sensing capability as a means to determine the concentration of the gases, or other chemicals, under study.", "author_names": [ "Swetha S Bobba", "Nisrine Hamdouni", "Kamna Pande", "Kejalakshmy Namassivayane", "Arti Agrawal", "Kenneth T V Grattan" ], "corpus_id": 218797296, "doc_id": "218797296", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design and optimization of perovskite plasmonic nano laser for operation at room temperature", "venue": "", "year": 2020 }, { "abstract": "We report a new gateway to enhance the sponatnesous emission rate of single quantum emitters by introducing a cavity in tilted nanofiber Bragg grating (TNFBG) We found that light emitter's coupling efficiency into the tilted grating structure's guided mode is 65% with 70 grating periods. This novel tilted structure has a high Q factor 1408.71 and low mode volume 0.66 microm3 an important requirement. Further, the Purcell factor of a quantum light emitter inside the nanofiber is nine times more than that of an emitter on the cavity's surface. The further optimized system with enhanced perfromance can be used the next generation quantum information and quantum metrology application.", "author_names": [ "Subrat Sahu", "Rajan Jha" ], "corpus_id": 229211286, "doc_id": "229211286", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Tilted Nanofiber Bragg Grating as an efficient photon collector from single quantum emitters: A new avenue", "venue": "", "year": 2020 }, { "abstract": "Scalable quantum photonic architectures demand highly efficient, high purity single photon sources, which can be frequency matched via external tuning. We demonstrate a single photon source based on an InAs quantum dot embedded in a micropillar resonator, which is frequency tunable via externally applied stress. Our platform combines the advantages of a Bragg micropillar cavity and the piezo strain tuning technique enabling single photon spontaneous emission enhancement via the Purcell effect and quantum dot (QD) with tunable wavelength. Our optomechanical platform has been implemented by integration of semiconductor based QD micropillars on a piezoelectric substrate. The fabricated device exhibits spontaneous emission enhancement with a Purcell factor of 4.4$\\pm$0.7 and allows for a pure triggered single photon generation with $g^(2)(0) 0.07 under resonant excitation. A quantum dot emission energy tuning range of 0.75 meV for 27 kV/cm applied to the piezo substrate has been achieved. Our results pave the way towards the scalable implementation of single photon quantum photonic technologies using optoelectronic devices.", "author_names": [ "Magdalena Moczala-Dusanowska", "Lukasz Dusanowski", "Stefan Gerhardt", "Yu-ming He", "Marcus Reindl", "Armando Rastelli", "Rinaldo Trotta", "Niels Gregersen", "Sven Hofling", "Christian Schneider" ], "corpus_id": 199129372, "doc_id": "199129372", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Strain Tunable Single Photon Source Based on a Quantum Dot Micropillar System", "venue": "ACS Photonics", "year": 2019 }, { "abstract": "Summary form only given. Metamaterials with near zero permittivity (ENZ) or equivalently plasmonic waveguides operated near their cut off frequency, when loaded with nonlinear materials, may efficiently boost the naturally weak nonlinear optical responses. In general, they can spatially extend the nonlinearity enhancement, producing even larger efficiencies and lower power needs, with a moderate Q factor of the associated resonance. The effects have been shown to effectively enhance the Kerr (kh(3) third order nonlinear susceptibility by several orders of magnitude (C. Argyropoulos et al. Phys. Rev. B 85, 045129, 2012) Moreover, the Purcell factor can also be enhanced at the ENZ operation without the usual restrictions of small volumes and high Q factor resonances. This may be interesting for future optical nanocircuits and laser designs.", "author_names": [ "Christos Argyropoulos", "Giuseppe D'Aguanno", "Andrea Alu" ], "corpus_id": 31192950, "doc_id": "31192950", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Temporal soliton propagation and second harmonic generation in epsilon near zero plasmonic waveguides", "venue": "2013 USNC URSI Radio Science Meeting (Joint with AP S Symposium)", "year": 2013 }, { "abstract": "This paper discusses in a comparative way the main operating parameters of various free electron lasers (FEL's) providing a useful tool for laser design and a comparative evaluation of the various lasers. We show that the various kinds of FEL's satisfy the same gain dispersion relation and differ only in a single coupling parameterk. The different gain regimes which are common to all FEL's are delineated. We find the small signal gain in all the gain regimes (warm and cold beam, low or high gain, single electron, collective or strong coupling interaction) The laser gain parameter, radiation extraction efficiency, maximum power generation, and spectral width are given and compared in the various kinds of FEL's and gain regimes. The maximum power generation of all FEL's (except Compton Raman scattering) is shown to be limited by an interaction region width parameter. This parameter and, consequently, the laser power are larger in the highly relativistic limit by a factor\\sim \\gamma_{0}in all bremsstrahlung FEL's, in comparison to Cerenkov Smith Purcell FEL's. Some expressions which were derived earlier for the magnetic bremsstrahlung FEL, like the expression for gain in the low gain regime with the space charge effect correction and the low gain expression for efficiency, are shown to be special cases of more general expressions.", "author_names": [ "Angela R Gover", "Phillip Sprangle" ], "corpus_id": 33276847, "doc_id": "33276847", "n_citations": 101, "n_key_citations": 1, "score": 0, "title": "A unified theory of magnetic bremsstrahlung, electrostatic bremsstrahlung, Compton Raman scattering, and Cerenkov Smith Purcell free electron lasers", "venue": "IEEE Journal of Quantum Electronics", "year": 1981 }, { "abstract": "Quantum communication places stringent requirements on single photon sources. Here we report a theoretical study of the cavity Purcell enhancement of two diamond point defects, the nickel nitrogen (NE8) and silicon vacancy (SiV) centers, for high performance, near on demand single photon generation. By coupling the centers strongly to high finesse optical photonic band gap cavities with modest quality factor Q=O (104) and small mode volume V=O ?3) these system can deliver picosecond single photon pulses at their zero phonon lines with probabilities of 0.954 (NE8) and 0.812 (SiV) under a realistic optical excitation scheme. The undesirable blinking effect due to transitions via metastable states can also be suppressed with O (10 4) blinking probability. We analyze the application of these enhanced centers, including the previously studied cavity enhanced nitrogen vacancy (NV) center, to long distance Bennett Brassard 1984 protocol quantum key distribution (QKD) in fiber based, open air terrestrial and satellite ground setups. In this comparative study, we show that they can deliver performance comparable with decoy state implementation with weak coherent sources, and are most suitable for open air communication", "author_names": [ "Chun-Hsu Su", "Andrew D Greentree", "Lloyd C L Hollenberg" ], "corpus_id": 118854369, "doc_id": "118854369", "n_citations": 27, "n_key_citations": 1, "score": 0, "title": "High performance diamond based single photon sources for quantum communication", "venue": "", "year": 2009 } ]
2D PtNi alloy
[ { "abstract": "Two dimensional CdS based hybrid nanostructures are intriguing materials with an application prospect in different fields such as sensing (i. e. photoresistors) and solar energy harvesting (photocatalysis, photovoltaics, and so forth) We report herein a colloidal synthetic path for interfacing metal and semiconductor with 2D CdS nanoplates. Selective growth of Au, Pt, and a PtNi alloy as well as Cu2 xS semiconductor is achieved on CdS nanoplates using controlled reduction of metallic precursors and thermal decomposition of a metal sulfide single source precursor using standard organic phase colloidal chemistry.", "author_names": [ "Helena Fridman", "Liang Tian", "Karam Shreteh", "Michael Volokh", "Taleb Mokari" ], "corpus_id": 210172948, "doc_id": "210172948", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Selective Growth of Metal Sulfide, Metal, and Metal Alloy on 2D CdS Nanoplates", "venue": "Frontiers in Materials", "year": 2019 }, { "abstract": "A computer analysis of the deformation mode of a billet and tool in the axially symmetric statement at the stage of established drawing of the PtNi alloy of the equiatomic composition is performed by the finite element method in the DEFORM 2D program medium. The geometry of the diamond tool providing a decrease in rigidity and weight without varying the basic parameters of the production process is proposed.", "author_names": [ "Olga M Ogorodnikova", "Evgeniy Borodin" ], "corpus_id": 138281851, "doc_id": "138281851", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Computer analysis of the deformation mode of the drawing tool for platinum alloys", "venue": "Russian Journal of Non Ferrous Metals", "year": 2016 }, { "abstract": "The computer analysis was made to evaluate the stress state of a workpiece and an axisymmetrically positioned tool at the stage of steady drawing process of PtNi equiatomic alloy using finite element method in the DEFORM 2D software environment. The diamond tool geometry is proposed to reduce hardness and weight without changing basic process parameters.", "author_names": [ "Array M Ogorodnikova", "Array M Borodin" ], "corpus_id": 138582600, "doc_id": "138582600", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "KOMP'IuTERNYI ANALIZ NAPRIaZhENNO DEFORMIROVANNOGO SOSTOIaNIIa INSTRUMENTA DLIa VOLOChENIIa PLATINOVYKh SPLAVOV", "venue": "", "year": 2016 }, { "abstract": "The catalytic performance of Pt based catalysts for oxygen reduction reactions (ORR) can generally be enhanced by constructing high index exposed facets (HIFs) However, the synthesis of Pt alloyed high index skins on 1D non Pt surfaces to further improve Pt utilization and stability remains a fundamental challenge for practical nanocrystals. In this work, Pd nanowires (NWs) are selected as a rational medium to facilitate the epitaxial growth of Pt and Ni. Based on the different nucleation and growth habits of Pt and Ni, a continuous PtNi alloy skin bounded with HIFs spiraled on a Pd core can be obtained. Here, the as prepared helical Pd@PtNi NWs possess high HIF densities, low Pt contents, and optimized oxygen adsorption energies, demonstrating an enhanced ORR mass activity of 1.75 A mgPt 1 and a specific activity of 3.18 mA cm 2 which are 10 times and 12 times higher than commercial Pt/C catalysts, respectively. In addition, the 1D nanostructure enables the catalyst to be highly stable after 30 000 potential sweeping cycles. This work successfully extends bulky high indexed Pt alloys to core shell nanostructures with the design of a new, highly efficient and stable Pt based catalyst for fuel cells.", "author_names": [ "Yueping Zhao", "Lu Tao", "Wei Dang", "Linlin Wang", "Meirong Xia", "Bo Wang", "Minmin Liu", "Faming Gao", "Jiujun Zhang", "Yufeng Zhao" ], "corpus_id": 85545522, "doc_id": "85545522", "n_citations": 32, "n_key_citations": 0, "score": 0, "title": "High Indexed PtNi Alloy Skin Spiraled on Pd Nanowires for Highly Efficient Oxygen Reduction Reaction Catalysis.", "venue": "Small", "year": 2019 }, { "abstract": "Abstract Novel enzyme mimic materials with excellent analytical properties and stable structure are essential for detecting H2O2 in many fields. In the present work, we prepare PtNi alloy/CeO2 plates/N doped carbon nanofibers (PtNi/CeO2/NCNFs) via heat treating the electrospun nanofiber hybrid of polyvinyl pyrrolidone and inorganic metal salts. Structural analysis indicate that PtNi alloy nanoparticles disperse on or around CeO2 nanoplates and PtNi alloy/CeO2 plates uniformly embed in porous NCNFs. A possible formation mechanism of PtNi alloy/CeO2 plates in NCNFs is put forward based on the electrostatic interaction of Ce3+ P t C l 6 2 and Ni2+ The special structure of PtNi/CeO2/NCNFs can initiate the synergistic effect and enhance its enzyme like electrocatalytic activity toward the reduction of H2O2. The PtNi/CeO2/NCNFs based sensor displays outstanding performances for H2O2 detection with wide linear range of 0.5 mM 15 mM, high sensitivity of 345.0 mA mM 1 cm 2, low detection limit of 0.025 mM, high selectivity and anti interference. Besides, the sensor possesses superior reproducibility and good stability. The RSD value of response current obtained from five parallel experiments is evaluated to be 2.36% and PtNi/CeO2/NCNFs GCE can still remain 98.5% of the initial response current value after being stored at 25 degC for 15 days. More importantly, the constructed sensor can be applied to detection of H2O2 content in cosmetics with satisfactory recovery (95.8% 103.8% and low relative standard deviation 4.5% These attractive properties make it possible for PtNi/CeO2/NCNFs to analyze H2O2 in real samples.", "author_names": [ "Huijuan Guan", "Jun Zhang", "Yong-zhi Liu", "Yafei Zhao", "Bing Zhang" ], "corpus_id": 105961330, "doc_id": "105961330", "n_citations": 27, "n_key_citations": 0, "score": 0, "title": "Rapid quantitative determination of hydrogen peroxide using an electrochemical sensor based on PtNi alloy/CeO2 plates embedded in N doped carbon nanofibers", "venue": "Electrochimica Acta", "year": 2019 }, { "abstract": "Abstract During the past few decades, substantial efforts have been made to explore high performance electrocatalysts for proton exchange membrane fuel cells due to the sluggish oxygen reduction reaction kinetics at the cathode. Among multifarious approaches, it has been demonstrated that alloying Pt nanocrystals with transition metals and introducing Pt based nanocrystals with high index facets have been recognized as effective strategies to facilitate the enhancement of oxygen reduction reaction performance. However, the current synthetic approach for preparing catalysts with high index facets is complicated. Herein, we demonstrate a straightforward one step method to synthesize three dimensional flower like high index faceted PtNi alloy nanocrystals constituted by abundant nano cones similar to the quadrihedron. The as prepared catalyst exhibits remarkably improved catalytic performance in comparison with PtNi 1, PtNi 2 and Pt/C, which is ascribed to a great number of high index facets and highly open hierarchical structure. The resultant high index faceted PtNi alloy nanocrystals deliver excellent mass activity of 1.76 A mg 1. Meanwhile, the material also displays a great stability after 20000 potential cycles. Consequently, the methodology proposed in this work may provide some guidance to boost the improvement of oxygen reduction reaction, and the 3D flower like high index faceted PtNi alloy nanocrystals have a great potential to be turned into effective cathode catalysts for proton exchange membrane fuel cells.", "author_names": [ "Shili You", "Pan Luo", "Ling Fang", "Jiaojiao Gao", "Li Liu", "Haitao Xu", "Huijuan Zhang", "Yu Wang" ], "corpus_id": 106386328, "doc_id": "106386328", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Unique hierarchical flower like PtNi alloy nanocrystals with enhanced oxygen reduction properties", "venue": "", "year": 2019 }, { "abstract": "Abstract The development of the fuel cell catalysts with high durability and high activity for oxygen reaction reduction remains a great challenge. Various material designs such as alloys, core@shell structure and shape control provide the promising ways to improve the electrocatalytic performance. Herein, on the basis of both the alloy effect and the nanotube structure effect, we demonstrate a high performance PtNi alloy catalyst with one dimensional nanotube structure via a galvanic replacement reaction combined with Kirkendall effect. Meanwhile, the PtNi alloy phase and the tube structure are selectively controlled by tuning the PtNi atomic ratio and the wall thickness of the nanotube, respectively. Subsequently, the understanding of the composition effect and the shape effect on the activity and the durability is systematically investigated. The optimized PtNi nanotube catalyst shows significant improvements on the activity (6.2 fold increase in specific activity compared to the commercial Pt/C) and the durability (only 8.6% loss in mass activity after 10000 cycles) attributing to the alloy effect by introducing Ni to the Pt lattice, the Pt rich surface and the shape effect of the unique one dimensional hollow tube structure.", "author_names": [ "Chuanting Fan", "Guoliang Wang", "Liangliang Zou", "Jian-hui Fang", "Zhiqing Zou", "Honbo Yang" ], "corpus_id": 164768456, "doc_id": "164768456", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Composition and shape controlled synthesis of the PtNi alloy nanotubes with enhanced activity and durability toward oxygen reduction reaction", "venue": "Journal of Power Sources", "year": 2019 }, { "abstract": "Graphite carbon nitride (g C3N4) supported PtNi alloy nanoparticles (NPs) were fabricated via a facile and simple impregnation and chemical reduction method and explored their catalytic performance towards hydrogen evolution from ammonia borane (AB) Interestingly, the resultant Pt0.5Ni0.5/g C3N4 catalyst affords superior performance, including 100% conversion, 100% H2 selectivity, yielding the extraordinary initial total turnover frequency (TOF) of 250.8 molH2 min 1 (molPt) 1 for hydrogen evolution from AB at 10 degC, a relatively low activation energy of 38.09 kJ mol 1, and a remarkable reusability (at least 10 times) which surpass most of the noble metal heterogeneous catalysts. This notably improved activity is attributed to the charge interaction between PtNi NPs and g C3N4 support. Especially, the nitrogen containing functional groups on g C3N4, serving as the anchoring sites for PtNi NPs, may be beneficial for becoming a uniform distribution and decreasing the particle size for the NPs. Our work not only provides a cost effective route for constructing high performance catalysts towards the hydrogen evolution of AB but also prompts the utilization of g C3N4 in energy fields.", "author_names": [ "Mingya Zhang", "Yun Wu", "Yue An", "Lixin Xu", "Chao Wan" ], "corpus_id": 207816942, "doc_id": "207816942", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Hydrogenation Production from Ammonia Borane over PtNi Alloy Nanoparticles Immobilized on Graphite Carbon Nitride", "venue": "", "year": 2019 }, { "abstract": "AbstractMonodisperse stone like PtNi alloy nanoparticles (NPs) were synthesized at room temperature using an inverse microemulsion method. The results of XRD, HRTEM, and EDS demonstrate that these NPs consist of a disordered alloy that has (a) a face centered cubic structure, (b) Pt/Ni atomic ratios of ~5:1, and (c) a large number of atoms exposed on the NP surface and enclosed by low index facets. The material was placed on a glassy electrode which then displayed superior response to glucose. Best operated at a potential of 0.43 V (vs. SCE) the electrode has the following features: (a) a wide linear range (from 0.5 mM to 40 mM) (b) rapid response <1 s) (c) a low detection limit (0.35 mM) and (d) a sensitivity of 40.17 mA mM 1cm 2) The NP sensor also is fairly selective over ascorbic acid, uric acid and fructose. The sensor has repeatability and durability for up to 30 days after manufacture. Graphical abstractNon enzymatic glucose sensor based on a glassy carbon electrode modified with PtNi NPS enclosed by low index facets. The sensor exhibits excellent features towards detecting glucose.", "author_names": [ "Rulei Wang", "Xinyi Liang", "Haiyan Liu", "Lan Cui", "Xiaoyue Zhang", "Changjiang Liu" ], "corpus_id": 49430556, "doc_id": "49430556", "n_citations": 31, "n_key_citations": 0, "score": 0, "title": "Non enzymatic electrochemical glucose sensor based on monodispersed stone like PtNi alloy nanoparticles", "venue": "Microchimica Acta", "year": 2018 }, { "abstract": "AbstractAn economic and effective Pt based alloy cocatalyst has attracted considerable attention due to their excellent catalytic activity and reducing Pt usage. In this study, PtNi alloy cocatalyst was successfully decorated on the g C3N4/GO hybrid photocatalyst via a facile chemical reduction method. The Eosin Y sensitized g C3N4/PtNi/GO 0.5% composite photocatalyst yields about 1.54 and 1178 times higher hydrogen evolution rate than the Eosin Y sensitized g C3N4/Pt/GO 0.5% and g C3N4/Ni/GO 0.5% samples, respectively. Mechanism of enhanced performance for the g C3N4/PtNi/GO composite was also investigated by different characterization, such as photoluminescence, transient photocurrent response, and TEM. These results indicated that enhanced charge separation efficiency and more reactive sites are responsible for the improved hydrogen evolution performance due to the positive synergetic effect between Pt and Ni. This study suggests that PtNi alloy can be used as an economic and effective cocatalyst for hydrogen evolution reaction. Graphical abstractA significant enhancement of photocatalytic H2 evolution is realized over the Eosin Y sensitized g C3N4/PtNi/GO composite with PtNi alloy as an efficient cocatalyst.", "author_names": [ "Peng Wang", "Lanlan Zong", "Zhongjie Guan", "Qiuye Li", "Jianjun Yang" ], "corpus_id": 24343688, "doc_id": "24343688", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "PtNi Alloy Cocatalyst Modification of Eosin Y Sensitized g C3N4/GO Hybrid for Efficient Visible Light Photocatalytic Hydrogen Evolution", "venue": "Nanoscale Research Letters", "year": 2018 } ]
THERMODYNAMICS AND KINETICS OF NANOCLUSTER FORMATION ON SEMICONDUCTOR SURFACES: THE EXAMPLE OF SI GROWTH ON SIC(0001)
[ { "abstract": "The molecular beam epitaxial growth of Si on SiC is investigated as a prototypical system for the formation of nanoclusters on semiconductor surfaces without interface intermixing effects. The investigation clearly indicates the presence of both equilibrium and non equilibrium effects with regard to the island formation. The existence of an equilibrium wetting layer thickness dequ independent from deposition rate R and temperature T is shown from the wetting behaviour of Si on SiC(0001) associated with a change in the surface reconstruction. After 3D island formation dequ is still present between the 3D islands, what clearly confirms that the growth mode of Si is Stranski Krastanov. The equilibrium wetting layer thickness is well described by equilibrium theory of heteroepitaxial growth considering strain as well as interface effects. At d dequ and conditions that are close to the equilibrium surplus Si atoms always aggregate instantly into 3D islands. Under dynamical conditions of growth far from equilibrium, the range of 2D layer by layer growth can be extended to an excess wetting layer thickness (dcrit dequ) Investigation of (dcrit dequ) as function of R and T indicated a transition from thermodynamically to kinetically controlled regimes of 2D 3D transition by a change in deposition condition. Furthermore, the 2D 3D transition initially starts with the formation a larger 2D islands and the simultaneous formation of smaller 3D islands, which likely acts as precursors for the formation and growth of larger 3D islands. For the growth of islands during further deposition surface mass transport of adatoms is rate controlling. Post deposition annealing of the highly stressed excess wetting layer (d dequ) gives rise to 3D island nucleation after deposition was stopped, what could be a long lasting process because adatoms stem mainly from the wetting layer decomposition.", "author_names": [ "Andreas Fissel" ], "corpus_id": 210124285, "doc_id": "210124285", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "THERMODYNAMICS AND KINETICS OF NANOCLUSTER FORMATION ON SEMICONDUCTOR SURFACES: THE EXAMPLE OF SI GROWTH ON SIC(0001)", "venue": "", "year": 2019 }, { "abstract": "Colloid and surface chemistry scope and variables sedimentation and diffusion and their equilibrium solution thermodynamics osmotic and Donnan equilibria the rheology of dispersions static and dynamic light scattering and other radiation scattering surface tension and contact angle application to pure substances adsorption from solution and monolayer formation colloidal structures in surfactant solutions association colloids adsorption at gas solid interfaces van der Waals forces the electrical double layer and double layer interactions electrophoresis and other electrokinetic phenomena electrostatic and polymer induced colloid stability appendix A examples of expansions encountered in this book appendix B units CGS SI interconversions appendix C statistics of discrete and continuous distributions of data appendix D list of worked out examples.", "author_names": [ "Paul C Hiemenz", "Raj Rajagopalan" ], "corpus_id": 94621791, "doc_id": "94621791", "n_citations": 4025, "n_key_citations": 151, "score": 0, "title": "Principles of colloid and surface chemistry", "venue": "", "year": 1977 }, { "abstract": "Part 1 Equilibria: fundamentals of pure component adsorption equilibria practical approaches of pure component adsorption equilibria pure component adsorption in microporous solids multicomponent adsorption equilibria heterogeneous adsorption equilibria. Part 2 Kinetics: fundamentals of diffusion and adsorption in porous media diffusion and adsorption in porous media Maxwell Stefan approach analysis of adsorption kinetics in a single homogeneous particle analysis of adsorption kinetics in a zeolite particle analysis of adsorption kinetics in a heterogeneous particle. Part 3 Measurement techniques: time lag analysis in diffusion and adsorption in porous media analysis of steady state and transient diffusion cells adsorption and diffusion measurement by a chromatography method kinetics of a batch adsorber.", "author_names": [ "Duong D Do" ], "corpus_id": 92026994, "doc_id": "92026994", "n_citations": 2047, "n_key_citations": 173, "score": 0, "title": "Adsorption analysis equilibria and kinetics", "venue": "", "year": 1998 }, { "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": "We present two new hybrid meta exchange correlation functionals, called M06 and M06 2X. The M06 functional is parametrized including both transition metals and nonmetals, whereas the M06 2X functional is a high nonlocality functional with double the amount of nonlocal exchange (2X) and it is parametrized only for nonmetals.The functionals, along with the previously published M06 L local functional and the M06 HF full Hartree Fock functionals, constitute the M06 suite of complementary functionals. We assess these four functionals by comparing their performance to that of 12 other functionals and Hartree Fock theory for 403 energetic data in 29 diverse databases, including ten databases for thermochemistry, four databases for kinetics, eight databases for noncovalent interactions, three databases for transition metal bonding, one database for metal atom excitation energies, and three databases for molecular excitation energies. We also illustrate the performance of these 17 methods for three databases containing 40 bond lengths and for databases containing 38 vibrational frequencies and 15 vibrational zero point energies. We recommend the M06 2X functional for applications involving main group thermochemistry, kinetics, noncovalent interactions, and electronic excitation energies to valence and Rydberg states. We recommend the M06 functional for application in organometallic and inorganometallic chemistry and for noncovalent interactions.", "author_names": [ "Yan Zhao", "Donald G Truhlar" ], "corpus_id": 98119881, "doc_id": "98119881", "n_citations": 16721, "n_key_citations": 236, "score": 0, "title": "The M06 suite of density functionals for main group thermochemistry, thermochemical kinetics, noncovalent interactions, excited states, and transition elements: two new functionals and systematic testing of four M06 class functionals and 12 other functionals", "venue": "", "year": 2008 }, { "abstract": "Abstract Graphene, a single atomic layer of graphite, has been the focus of recent intensive studies due to its novel electronic and structural properties. Metals grown on graphene also have been of interest because of their potential use as metal contacts in graphene devices, for spintronics applications, and for catalysis. All of these applications require good understanding and control of the metal growth morphology, which in part reflects the strength of the metal graphene bond. Also of importance is whether the interaction between graphene and metal is sufficiently strong to modify the electronic structure of graphene. In this review, we will discuss recent experimental and computational studies related to deposition of metals on graphene supported on various substrates (SiC, SiO 2 and hexagonal close packed metal surfaces) Of specific interest are the metal graphene interactions (adsorption energies and diffusion barriers of metal adatoms) and the crystal structures and thermal stability of the metal nanoclusters.", "author_names": [ "Xiaojie Liu", "Yong Han", "James W Evans", "Albert K Engstfeld", "Rolf Jurgen Behm", "Michael C Tringides", "Myron Hupalo", "Haiqing Lin", "Li Hua Huang", "Kai-Ming Ho", "David Victor Appy", "Patricia A Thiel", "Cai-Zhuang Wang" ], "corpus_id": 39796186, "doc_id": "39796186", "n_citations": 85, "n_key_citations": 0, "score": 0, "title": "Growth morphology and properties of metals on graphene", "venue": "", "year": 2015 }, { "abstract": "Semiconductor nanowires refer to crystal structures with diameters as small as a few nanometers and lengths up to tens of micrometers or even millimeters. Nanowires can be produced either through conventional subtractive nanofabrication processes, via lithography and etching, or through additive nanomaterial growth methods. The quality of \"top down\" fabricated nanowires are in principle determined by the starting material, although the size reduction techniques used to fabricate these structures inevitably introduce damage (e.g. roughness) that can degrade overall quality. The top down approach, which relies heavily on the precision of the lithography and etching tools, also becomes less cost effective when scaling to ca. 10 nm size regimes. In this chapter we focus on nanowires produced through \"bottom up\" growth methods, in which the critical dimension (e.g. the nanowire diameter) is limited not by lithography precision but controlled during chemical synthesis with atomic resolution. In particular, the catalyst mediated vapor liquid solid (VLS) process is discussed in detail since this approach enables the growth of a broad range of nanowire materials with controlled structure, morphology, composition, and doping.", "author_names": [ "Lin Chen", "Wei Lu", "Charles M Lieber" ], "corpus_id": 53055768, "doc_id": "53055768", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Chapter 1:Semiconductor Nanowire Growth and Integration", "venue": "", "year": 2014 }, { "abstract": "By exploiting the extremely large effective cross sections {10}\\ensuremath{ }17} {10}\\ensuremath{ }16}\\mathrm{cm}{2}\\mathrm{molecule} available from surface enhanced Raman scattering (SERS) we achieved the first observation of single molecule Raman scattering. Measured spectra of a single crystal violet molecule in aqueous colloidal silver solution using one second collection time and about $2\\ifmmode\\times\\else\\texttimes\\fi{{10}{5}\\mathrm{W}\\mathrm{cm}{2} nonresonant near infrared excitation show a clear `fingerprint' of its Raman features between 700 and $1700{\\mathrm{cm}\\ensuremath{ }1} Spectra observed in a time sequence for an average of 0.6 dye molecule in the probed volume exhibited the expected Poisson distribution for actually measuring 0, 1, 2, or 3 molecules.", "author_names": [ "Katrin Kneipp", "Harald Kneipp", "Lev T Perelman", "Irving Itzkan", "Ramachandra R Dasari", "M S Feld" ], "corpus_id": 12377332, "doc_id": "12377332", "n_citations": 5255, "n_key_citations": 49, "score": 0, "title": "Single Molecule Detection Using Surface Enhanced Raman Scattering (SERS)", "venue": "", "year": 1997 }, { "abstract": "Nanostructured surfaces can be broadly defined as substrates in which the typical features have dimensions in the range 1?100?nm (although the upper limit of 100?nm may be relaxed to greater sizes in some cases, depending on the material and the specific property being investigated) The recent surge of interest in these systems stems from the remarkable effects that may arise from the critical size reduction. Interesting novel properties (catalytic, magnetic, ferroelectric, mechanical, optical and electronic) occur as we reduce the dimensions from a practically infinite (and periodic) solid crystal to a system composed of a relatively small number of atoms. So far, nanostructured materials or nanomaterials are perhaps the only sub field of nanoscience that has made the transition from fundamental science to real world applications, thus becoming a technology (a good example of this are nanostructured surface coatings) This paper describes some selected examples of recent progress in the study of nanostructured surfaces. Surface reconstructions, which occur either naturally or as a consequence of the interaction with adsorbates, are discussed because of their importance in model chemical reactions and for their potential use as templates for the ordered growth of nanostructures. Supramolecular assemblies and molecular nanostructures, resulting from the balance between molecule?molecule and molecule?surface interactions, are described because of their fundamental interest and their potential use in nanoelectronic devices. Recent progress in the growth of semiconductor nanostructures, in particular Ge?Si and InAs?GaAs, is briefly reviewed. A few selected examples of nanostructured functional materials, such as ferroelectric and magnetic nanostructures, are discussed in view of their potential for applications in future data storage devices. Nanostructured materials used in catalysis and gas sensor applications are briefly described. Finally, perspectives and future challenges in this emerging field of research are also discussed.", "author_names": [ "Federico Rosei" ], "corpus_id": 4990679, "doc_id": "4990679", "n_citations": 216, "n_key_citations": 1, "score": 0, "title": "Nanostructured surfaces: challenges and frontiers in nanotechnology", "venue": "", "year": 2004 }, { "abstract": "Throughout this thesis, we have studied ZnO and its properties in a bottom up manner through a dimensionality range starting from 0D nanoparticles to 3D bulk phases. For the 0D clusters and the 2D nanofilms studied we also considered the effect of a support in models designed to study ZnO thin film growth on the Ag(111) surface. In chapter 3, we have studied ZnO nanoclusters on a Ag support and compared their properties with free space ZnO nanoclusters. In this chapter we highlighted the importance of the presence of the support during the global optimization of the clusters (i.e. as opposed to global optimization of the clusters in free space and then introducing a support) Our results show that the presence of the support strongly affects the energetic stability ranking of the nanocluster isomers. More drastically, after a certain cluster size, the support also stabilizes selectively 2D type structures, which are not stable in free space, with respect to the 3D clusters. The extra stabilization of supported 2D clusters is attributed mainly to the contact area, which is evidently greater for 2D clusters where all the atoms can interact with the surface. The importance of the contact are is also observed for 3D clusters, as ellipsoid bubbles or inflated double layer clusters being of lower energy than more spherical clusters on the support whereas the latter, more symmetric 3D clusters are more stable in free space. Matching of the cluster structure with the surface morphology was found to be another factor determining cluster stability. The Zn3O3 sixmembered ring, which is one of the main motifs for both 3D and 2D clusters, matches best with the Ag(111) surface because it follows the same six fold (C6) symmetry (or its trigonal C3 subgroup with a three fold axis, taking into account the distinction between Zn and O atoms) However because of the lattice size differences, such matching dies away for larger ZnO clusters. The preferential stabilities of the 2D structures of ZnO clusters can be seen as the initial stages of thin film growth and is found to be in line with the experimentally observed layered ZnO sheets on the Ag(111) surface. In Chapter 4, we have considered a full 2D ZnO sheet on Ag(111) surface and also investigated also how H atoms interact with it. Following our results for ZnO nanoclusters on the Ag surface, we highlighted the importance of the degree of 2D ZnO:Ag(111) unit cell commensurability for calculating accurate sheeton substrate binding energies. We have found a 8:9 commensurate monolayer to be more favored with interatomic potentials and a 7:8 commensurate monolayer with DFT calculations, where the latter is found in experiment. Our calculations showed no evidence of charge transfer or covalent bonding between the Ag(111) surface and the 2D ZnO sheet, but did show that the ZnO sheet and the Ag(111) surface exhibit small structural distortions in order to maximize their mutual interaction. Calculations of the unsupported 2D ZnO sheet interacting with hydrogen provided strong evidence for H forming a low energy Zn 4s H 1s multi center bonding state when passing through a Zn3O3ring of the 2D ZnO sheet, thus allowing for relatively facile H transport through the sheet. In chapter 5, we have extended our study of supported 2D ZnO nanofilms with higher coverage models, including triangular islands on top of two full monolayers, prepared to model the experimental system. Our results showed that the triangular adlayer islands induce a transition to the WZ structure in the island core and in local region in the two layers immediately below the island core. The islands are also found to have BCT structured reconstructions on their edges and T1 structured reconstructions on their corners. These models are found to better match the experimental structural data for the experimental 2.7 ML Ag supported ZnO film with respect to models assuming a purely layered or a purely WZ structure. In chapter 6, we focused on 4ML nanofilms and compared bulk and the 4 ML nanofilm poymorphism of ZnO. Our results revealed that the stability range of nanofilms and their energetic ordering are radically different than that of bulk polymorphs. We have developed a method to generate a wide range of new low energy nanofilm and bulk polymorphs using nets as a basis, and showed that there exist at least three nanofilm structures with trigonal basal plane symmetry compatible epitaxial growth on fcc metal (111) surfaces that are more stable than layered ZnO. While confirming the previous theoretical studies predicting the BCT ZnO phase as being the lowest energy free standing nanofim for small thicknesses, we obtained a range of structurally related and near energetically degenerate phases, indicating there exists BCT polytypism. With increasing thickness we found that atomically reconstructed wz ZnO becomes more stable than BCT ZnO for ~14 MLs, and is always more stable than non reconstructed wz ZnO. We have also stressed the influence of strain on polymorphism by showing that BCT ZnO and layered ZnO nanofilms are unstable to novel polymorphs under in plane strain. Together with the T1 structures and BCT structures which were also predicted as reconstructions on island corners in the previous chapter, our results strongly suggest that many new nanofilm polymorphs should be experimentally accessible, and in some cases, may have even already been observed. In chapter 7, we focused on bulk polymorphism and, specifically, investigated the effect of nanoporosity. Our results showed that both energetic instability and band gap increase with nanoporosity and we predicted that nanoporosity could induce band gap increases of up to ~1.5 eV relative to wurtzite ZnO. We showed that the band gap increase is related with bandwidth changes in the conduction band and the valance band. We suggested that the underlying physical mechanism for this effect is that introducing nanoporosity, and thus periodic internal void space, restricts extended orbital overlaps and thus decreases bandwidths. Due to the generality of this argument, we expect that nanoporosity could similarly affect bandgap values in a wide range of materials and could be employed as a band gap engineering method.", "author_names": [ "Ilker Demiroglu" ], "corpus_id": 137252018, "doc_id": "137252018", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Effect of Dimensionality and Polymorphism on the properties of ZnO", "venue": "", "year": 2014 } ]
A floating gate and its application to memory devices
[ { "abstract": "A structure has been proposed and fabricated in which semipermanent charge storage is possible. A floating gate is placed a small distance from an electron source. When an appropriately high field is applied through an outer gate, the floating gate charges up. The charges are stored even after the removal of the charging field due to much lower back transport probability. Stored charge density of the order of 1012/cm2 has been achieved and detected by a structure similar to an metal insulator semiconductor (MIS) field effect transistor. Such a device functions as a bistable memory with nondestructive read out features. The memory holding time observed was longer than one hour. These preliminary results are in fair agreement with a simple analysis.", "author_names": [ "Dawon Kahng", "Simon M Sze" ], "corpus_id": 110201526, "doc_id": "110201526", "n_citations": 384, "n_key_citations": 6, "score": 2, "title": "A floating gate and its application to memory devices", "venue": "", "year": 1967 }, { "abstract": "", "author_names": [ "K Kahng", "Simon M Sze" ], "corpus_id": 110835925, "doc_id": "110835925", "n_citations": 38, "n_key_citations": 0, "score": 0, "title": "A floating gate and its application to memory devices", "venue": "", "year": 1967 }, { "abstract": "Non volatile memories (NVM) are playing a very important role in the semiconductor market, thanks in particular to Flash technology, that is used mainly in cellular phones and other types of electronic portable equipment (mobile PCs, mp3 players, digital cameras and so on) This trend will continue in the coming years and it is expected that portable systems will demand even more from NVM either with high density and very high writing throughput for data storage application, or with fast random access for code execution in place. Although Flash memory technology has been able to follow the evolution of the semiconductor roadmap, since its introduction in late 1980s, and further scaling down is forecasted to continue into the coming years, there are some physical limitations to be faced and the downscaling beyond the 45 nm technology node is still considered critical. Hence other technologies, alternative to floating gate devices, have been proposed and are under investigation. These new proposals exploit different physical mechanisms to store the information, like magnetism, ferroelectricity, solid electrolysis, and phase change. Among the different NVM based on these mechanisms, apart from the floating gate concept, phase change memories (PCM) also called ovonic unified memories (OUM) are one of the most promising candidates to become a mainstream NVM, having the potentiality to improve the performance compared to Flash random access time, read throughput, direct write, bit granularity, endurance as well as to be scalable beyond Flash technology.", "author_names": [ "Roberto Bez", "A Pirovano", "Fabio Pellizzer" ], "corpus_id": 137570527, "doc_id": "137570527", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Phase change Memories", "venue": "", "year": 2005 }, { "abstract": "Among the many possible device confi gurations of fl ash memory, fi eld effect transistor (FET) based memory with a fl oating gate architecture is considered to be a promising candidate towards the ultimate goal of fl ash memory due to its single transistor realization, non destructive read out, and compatibility with complementary metal oxide semiconductor (CMOS) devices. 1 5 Floating gate FET memory with metal nanoparticles (NPs) embedded in the gate dielectric is a way to replace planar fl oating gates to meet the requirements of fast data access and high density for the next generation of fl ash memory. 6 12 However, poor charge retention time induced by the thin tunneling dielectric layer is a drawback for NP fl oatinggate memory devices. 13 Simply increasing the thickness of the tunneling dielectric layer would degrade the program/ erase speed and increase the power consumption. 12 On this regard, as an alternative approach, the double NP fl oating gate structure has been proposed to achieve better retention properties. 13 15 In previous reports, double NP fl oating gates have generally been made with the same materials. The retention time could be improved by preventing the trapped charge carriers leaking back to the channel through the energy barrier arising between the upper and lower fl oating gates. Nevertheless, most double NP fl oating gates consisting of two layers of NPs fabricated by chemical synthesis or thermal evaporation could not form NP pairs in the vertical direction. Additionally, the double NP fl oating gate structure may result in a poor interface between the NPs and the dielectric layer, which would have an adverse impact on the overall device performance. Therefore, developing an appropriate upper fl oating gate material with the following properties is necessary for technological applications: i) a suitable work function to set up an energy barrier so a long retention time is obtained; ii) a large area to achieve an accurate spatial distribution on the lower fl oating gate; and iii) a fl attened surface to improve the interface quality between the double fl oating gate and the dielectric layer. As one of the thinnest materials ever known in the universe, graphene", "author_names": [ "Su-Ting Han", "Ye Zhou", "Chundong Wang", "Lifang He", "Wenjun Zhang", "Vellaisamy A L Roy" ], "corpus_id": 28245085, "doc_id": "28245085", "n_citations": 146, "n_key_citations": 0, "score": 0, "title": "Layer by layer assembled reduced graphene oxide/gold nanoparticle hybrid double floating gate structure for low voltage flexible flash memory.", "venue": "Advanced materials", "year": 2013 }, { "abstract": "In this work we explore the use of extension less doping schemes for fully depleted devices [two dimensional (2D) ultra thin body and buried oxide layer (BOX) planar devices (UTBB) three dimensional (3D) multi gate field effect transistor devices with the conduction channels wrapped around silicon (Si) fins (FinFETs) and built on bulk Si or silicon on insulator (SOI) substrates] suitable for advanced logic, memory and dense circuit applications. We demonstrate that by using Si epitaxial raised source (S)/drain (D) (SEG) followed by highly doped drain (HDD) only implantations (I/I) or by using doped SEG and no I/I: 1) lower off state current (IOFF) and drain induced barrier lowering effect (DIBL) 2) steeper sub threshold slope (SS) 3) higher on state/off state currents ratio (ION/IOFF) and 4) higher retention times [for floating body random access memory (FBRAM) on UTBB] can be obtained, while reducing cost and cycle time with less critical I/I photos. SEG facet formation can be controlled by the spacers shape and epi pre clean step and its impact on device characteristics for logic and FBRAM applications is also analyzed.", "author_names": [ "Anabela Veloso", "A De Keersgieter", "Marc Aoulaiche", "Malgorzata Jurczak", "Aaron Voon-Yew Thean", "Naoto Horiguchi" ], "corpus_id": 111272961, "doc_id": "111272961", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Two and Three Dimensional Fully Depleted Extension Less Devices for Advanced Logic and Memory Applications", "venue": "", "year": 2013 }, { "abstract": "Abstract In this work we explore the use of extension less doping schemes for fully depleted devices [2D: ultra thin body and BOX (UTBB) planar devices; 3D: FinFETs on bulk Si or SOI substrates] suitable for advanced logic, memory and dense circuit applications. We demonstrate that by using Si epitaxial raised S/D (SEG) followed by HDD only implantations (I/I) or by using doped SEG and no I/I: 1) lower IOFF and DIBL; 2) steeper sub threshold slope (SS) 3) higher ION/IOFF ratio; and 4) higher retention times (UTBBFBRAM) can be obtained, while reducing cost cycle time with less critical I/I photos. SEG facet formation can be controlled by the spacers shape and epi pre clean step and its impact on device characteristics for logic and FBRAM applications is also analyzed. Introduction Ultra thin body fully depleted devices [planar on ultra thin BOX (UTBB) and FinFET based multi gate structures (MuGFETs) have long been considered an attractive option for enabling further CMOS scaling beyond the 22nm technology node, thanks to their improved electrostatics and steeper sub threshold slopes (SS) with reduced VT variability due to lower channel dopants concentration [1 8] For both architectures, however, the extremely thin body poses new integration challenges, namely for junction engineering and the extendibility of conventional doping techniques such as ion implantation (with tilt angle restrictions due to resist shadowing at tight pitch) parasitics and series resistance (RS/D) control. Improved morphology of the c Si body and near zero tolerance Si loss is required. In this paper, several extension less strategies for scaled UTBB and FinFET devices are evaluated for improved performance, short channel effects (SCE) and variability control. Increased interest in potential memory architecture alternatives to DRAM, such as one transistor floating body RAM (1T FBRAM) [9,10] will also be addressed in this work through the use of a process flow fully compatible with UTBB logic technology. Device fabrication A schematic of the process flow used for fully depleted devices fabrication is shown in Fig.1, for both 2D (UTBB planar) and 3D (FinFETs on bulk Si or SOI substrates) Extension less devices were fabricated with a narrower 1 spacer (CD15nm after SEG) followed by SEG HDD I/I RTA as illustrated in Fig.2. An alternative I/I free approach consists in doing doped SEG RTA. Reference devices include extensions I/I prior to SEG HDD I/I RTA, for both 2D and 3D architectures, with total spacer width prior to silicidation similar for all devices. Gate stack consists of (HfSiON or HfO2)/TiN for logic, 5nm SiO2/TiN for 1T FBRAM. Device results and discussion Fig.3 shows lower IOFF values for extension less SOI FinFET devices, consistent with the expected reduced gate overlap. 7tilt I/I was used here for all devices under comparison to enable pitch scaling without resist shadowing effects. These devices also exhibit excellent SCE behavior with the ID VG curves in Fig.4 highlighting the lower off state current obtained with extension less (SEG HDD I/I RTA) vs. reference (Extension I/I SEG HDD I/I RTA) implant strategies, corresponding to a lower DIBL~36mV/V and SS~70mV/dec. Furthermore, it is important to mention the better quality, defect free SEG less Rout variability) expected to be obtained when starting from undoped fins [3,5] as is the case with the extension less I/I approach. An alternative extension less and I/I free doping technique is illustrated in Fig.5, where a RTA anneal is used to drive dopants from the in situ doped SEG grown on the S/D areas of a bulk FinFET device. The RTA condition used determines the dopant (As in Fig.5) diffusion profile and resulting doping contours in the top and vertical channels. Benchmarking with reference devices (bulk FinFETs with conformal doping by I/I) TCAD simulations were performed for assessing the impact of several process parameters changes, such as spacer width variations, on junctions profile and device characteristics. Overall, as observed before for extension less devices built with [SEG HDD I/I RTA] steeper SS, smaller DIBL, lower IOFF and higher ION/IOFF ratio values are also obtained for these I/I free devices (Figs.6,7) Wider offset (1) spacers translate into reduced gate overlap and a further increase on the difference for these parameters with regards to the implantedreference, with a compromise needed to also keep high absolute values for ION. Fig.8 shows that increasing the Si recess depth (10 40nm) prior to SEG growth leads to higher drive currents due to a more effective fin doping, but at the expense of a reduction in the ION/IOFF ratio and a small (eventually leveling off) DIBL increase. TEM image and schematics of UTBB planar devices fabricated for use as 1T FBRAM are shown in Fig.9, with 14nm thick Si channel and 18nm thick BOX. Also in this case, improved DIBLLgate behavior is measured for extension less devices built with the I/I sequence: SEG HDD I/I RTA (Fig.10) Fig.11 shows devices with and without SEG faceting, depending on the spacers bottom shape and the HF time used in epi pre clean. A faceted SEG in S/D has been shown to reduce RS/D and minimize gate toS/D parasitic capacitance [4,6] Its impact on the lateral electric field for a Lgate70nm device in the hold \"0\" state is shown in Fig.12. A lower maximum field at gate edges was simulated for extension less devices, more so if SEG has no facets. This results in a 5 retention time improvement for 1T FBRAM extensionless devices with faceted SEG, with further improvement expected to occur with facet less SEG due to its even lower maximum field (Fig.13) Retention is determined by the \"0\" state degradation (holes generation occurring during \"0\" state hold) with band toband tunneling and trap assisted tunneling mechanisms limiting the retention time [11] and responsible for the field dependence seen here. At the same time, Fig.13 shows that similar retention time distributions are obtained for the different type of devices evaluated suggesting similar traps, and generation/recombination (GR) centers distributions. For logic UTBB planar devices (see Fig.14) the two doping approaches (with and without extensions I/I) yield results in line with those obtained for FinFETs and for 1T FBRAM UTBB devices. This is illustrated by the simulation results plotted in Figs.15 and 16. Overall, lower IOFF, steeper SS, and smaller DIBL values can be obtained for extension less devices with optimized 1 spacers width. Again, careful balance between IOFF reduction and ION increase is needed, depending on final device application, including 6T SRAM for which lower IOFF values are of the uttermost importance. Figs.15,16 also show that, for similar HDD only I/I conditions, SEG faceting results in considerably improved drive currents with no significant IOFF penalty, though at the expense of higher DIBL and SS values. Conclusions A comprehensive evaluation of two extension less doping schemes suitable for scaled 2D and 3D fully depleted devices for logic and memory applications was reported: HDD only I/I after SEG or I/I free, doped SEG, both followed by RTA. Results show: lower IOFF and DIBL, steeper SS, higher ION/IOFF ratio, and higher retention times (UTBB FBRAM) with reduced cost cycle time. SEG faceting control, key for parasitics and variability reduction, leads to improved performance for logic and memory. References [1] J. Kavalieros et al. VLSI Tech. Dig. 2006, 62; [2] H. Kawasaki et al. IEDM Tech. Dig. 2008, 237; [3] T. Merelle et al. IEDM Tech. Dig. 2008, 241; [4] K. Cheng et al. VLSI Tech. Dig. 2009, 212; [5] A. Veloso et al. IEDM Tech. Dig. 2009, 301; [6] K. Cheng et al. VLSI Tech. Dig. 2011, 128; [7] A. Veloso et al. Jpn. J. Appl. Phys. 50, 04DC16, 2011; [8] http:/newsroom.intel.com/docs/DOC2032; [9] I. Ban et al. VLSI Tech. Dig. 2008, 92; [10] Z. Lu et al. IEDM Tech. Dig. 2010, 288; [11] O. K. B. Lui et al. Solid State Elect. 41(4) 575, 1997.", "author_names": [ "Anabela Veloso", "A De Keersgieter", "Marc Aoulaiche", "Malgorzata Jurczak", "Aaron Voon-Yew Thean", "Naoto Horiguchi" ], "corpus_id": 183589842, "doc_id": "183589842", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "2D and 3D Fully Depleted Extension less Devices for Advanced Logic and Memory Applications", "venue": "", "year": 2012 }, { "abstract": "This paper describes the narrow and non spread distribution of threshold voltage in MONOS (Metal oxide nitride oxide semiconductor) memory cell array. We fabricated 4 Mbit MONOS memory test chip using 0.25 /spl mu/m technology. The gate length of the memory cell is shrunk to 0.18 /spl mu/m. The distributions of threshold voltage in many operations are evaluated. As a result range of the distribution of threshold voltage keeps narrow in program and erase operation. It also keeps narrow in heat treatment of 300/spl deg/C. These characteristics are also good advantages of MONOS memory device for multi bit memory applications. It is also shown that there is a possibility to achieve non verify operation in both program and erase cycle. The MONOS memory device is a promising form of nonvolatile memory for use in cheaper than floating gate (FG) yet highly reliable embedded applications.", "author_names": [ "Toshio Terano", "Hiroyuki Moriya", "Akihiro Nakamura", "H Kosaka", "A Hashiguchi", "Kazumasa Nomoto", "I Fttjlwara", "Tsukasa Kobayashi" ], "corpus_id": 25900977, "doc_id": "25900977", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Narrow distribution of threshold voltages in 4 Mbit MONOS memory cell arrays and its impact on cell operation", "venue": "International Electron Devices Meeting. Technical Digest (Cat. No.01CH37224)", "year": 2001 }, { "abstract": "The quest for mass storage and the diversity of end user applications led to an aggressive scaling of the NAND Flash memory. A key factor to its success is the high density integration potential, which allows fabrication of large memory arrays. Reduction of the feature size below 40 nm may, however, require modifications of the conventional floating gate (FG) cell architecture, due to lack of physical space between neighboring cells [1] which no longer allows wrapping of the control gate (CG) over the floating gate (FG) This has consequences on both intraas well as inter cell levels.", "author_names": [ "Bogdan Govoreanu", "Jorge A Kittl", "Joeri de Vos", "A Rothschild", "Pieter Blomme", "Dirk Wellekens", "D Ruiz Aguado", "Malgorzata Jurczak", "Jan Van Houdt" ], "corpus_id": 62153407, "doc_id": "62153407", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "The Flash Memory Cell for the Nodes to Come: Material Requirements from a Device Perspective", "venue": "", "year": 2009 }, { "abstract": "Nanocrystal (NC) floating gate flash memory is considered to be one of the most promising candidates to replace conventional highly doped polysilicon floating gate flash memory technology widely used today. [1] Metal NCs is more desirable compared to its semiconductors to work as charge storage storage node, because metals usually have large work function and can be engineered down to 1 nm without decreasing potential well depth. [2, 3] However, most metal NCs are easily oxidized and diffuse into the surrounding dielectric under high temperature process conditions, resulting in bad NC dielectric interface quality and the degradation of the memory performance.[4] In this paper, for the first time, we present an approach using Ruthenium (Ru) NC buried in HfO2 matrix to work as charge storage nodes, which can create a robust NC high K dielectric interface. Combined with some advantages of Ruthenium, good memory device performance can be achieved. Device Fabrication: The device fabrication started with a P type silicon substrate with the resistivity about 1 10 .cm. After a standard RCA clean and a 1:40 HF solution dip to remove native oxide, about 43A HfO2 was deposited by atomic layer deposition (ALD) as tunneling oxide. Then a thin Ruthenium film was deposited by physical vapor deposition process. After that, the Ruthenium nanocrysal matrix was formed by a rapid RTPDA process of the samples in N2. Then 150 A HfO2 control oxide was deposited by reactive DC sputtering in an Ar/O2 ambient, and finally 2000 A TaN electrode deposited by reactive DC sputtering was deposited as electrode. A control sample without Ruthenium nanocrystals was also fabricated to check for charge trapping in the dielectrics. Device Structure Verification and Electrical Measurements: The memory cell diagram is shown in figure 1. Atomic force Microscopy was used to check the results of the Ruthenium nanocrystal formation by RTPDA process. In our study, it shows that the RTPDA process parameters, including annealing temperature(T) and annealing time(t) and original film thickness(d) has deep impact on the formation of Ruthenium nanocrystal on HfO2 surface. Figure 2 shows the Ruthenium nanocrystal formation results under different conditions: (a) d=2 nm, T=600 C q t=30 S, (b) d=5 nm, T=700 C", "author_names": [ "Hai Liu", "Domingo A Ferrer", "Sanjay K Banerjee" ], "corpus_id": 138322990, "doc_id": "138322990", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Student Paper Formation of Ruthenium Nanocrystals Buried in HfO2 Matrix for Nonvolatile Memory Applications", "venue": "", "year": 2009 }, { "abstract": "Nanocrystal (NC) floating gate flash memory is considered to be one of the most promising candidates to replace conventional highly doped polysilicon floating gate flash memory technology widely used today. [1] Metal NCs is more desirable compared to its semiconductors to work as charge storage storage node, because metals usually have large work function and can be engineered down to 1 nm without decreasing potential well depth. [2, 3] However, most metal NCs are easily oxidized and diffuse into the surrounding dielectric under high temperature process conditions, resulting in bad NC dielectric interface quality and the degradation of the memory performance.[4] In this paper, for the first time, we present an approach using Ruthenium (Ru) NC buried in HfO2 matrix to work as charge storage nodes, which can create a robust NC high K dielectric interface. Combined with some advantages of Ruthenium, good memory device performance can be achieved.", "author_names": [ "Hai Liu", "Domingo A Ferrer", "Sanjay K Banerjee" ], "corpus_id": 26882690, "doc_id": "26882690", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Formation of Ruthenium nanocrystals buried in HfO2 matrix for nonvolatile memory applications", "venue": "2009 International Semiconductor Device Research Symposium", "year": 2009 } ]
Room-temperature ultraviolet nanowire nanolasers
[ { "abstract": "Room temperature ultraviolet lasing in semiconductor nanowire arrays has been demonstrated. The self organized, <0001> oriented zinc oxide nanowires grown on sapphire substrates were synthesized with a simple vapor transport and condensation process. These wide band gap semiconductor nanowires form natural laser cavities with diameters varying from 20 to 150 nanometers and lengths up to 10 micrometers. Under optical excitation, surface emitting lasing action was observed at 385 nanometers, with an emission linewidth less than 0.3 nanometer. The chemical flexibility and the one dimensionality of the nanowires make them ideal miniaturized laser light sources. These short wavelength nanolasers could have myriad applications, including optical computing, information storage, and microanalysis.", "author_names": [ "Michael H Huang", "Samuel Mao", "Henning Feick", "Haoquan Yan", "Yiying Wu", "Hannes Kind", "Eicke R Weber", "Richard E Russo", "Peidong Yang" ], "corpus_id": 4283353, "doc_id": "4283353", "n_citations": 7147, "n_key_citations": 17, "score": 1, "title": "Room Temperature Ultraviolet Nanowire Nanolasers", "venue": "Science", "year": 2001 }, { "abstract": "", "author_names": [ "Michael H Huang", "Samuel S Mao", "Henning Feick", "Haoquan Yan", "Yiying Wu", "Hannes Kind", "Eicke R Weber", "Richard E Russo", "Peidong Yang" ], "corpus_id": 197067478, "doc_id": "197067478", "n_citations": 699, "n_key_citations": 21, "score": 0, "title": "Room Temperature Ultraviolet Nanowire Nanolasers.", "venue": "", "year": 2001 }, { "abstract": "Well ordered nanowires of the hexagonal wurtzite ZnO having an average diameter of 80 nm, a typical length of 12 mm, and a mean packing density of 7.5 nanowires mm 2 have been directly grown on Zn foil in a preferred [0001] direction by a hydrothermal process and employed for room temperature ultraviolet nanolasers. The lasing action of arrayed ZnO nanowires has been observed from 370 to 400 nm with threshold irradiance of 25 kW cm 2. Photoluminescence decays biexponentially: the fast component is attributed to free exciton decay, and the slow one is to bound exciton decay. The amplitude of the fast component increases whereas its lifetime decreases with the increment of threshold irradiance, suggesting that ZnO nanowire arrays undergo a change in the lasing mechanism from exciton exciton scattering to electron hole plasma recombination.", "author_names": [ "Jong-Yeob Kim", "Hyeok Jeong", "Du-Jeon Jang" ], "corpus_id": 136843967, "doc_id": "136843967", "n_citations": 27, "n_key_citations": 0, "score": 0, "title": "Hydrothermal fabrication of well ordered ZnO nanowire arrays on Zn foil: room temperature ultraviolet nanolasers", "venue": "", "year": 2011 }, { "abstract": "Nanolasers with ultra compact footprint can provide high intensity coherent light, which can have various potential applications in high capacity signal processing, biosensing, and sub wavelength imaging. Among various nanolasers, those lasers with cavities surrounded with metals have shown to have superior light emission properties due to the surface plasmon effect providing better field confinement capability and allowing exotic light matter interaction. In this study, we realize a robust ultraviolet ZnO nanolaser by using silver to strongly shrink the mode volume. The nanolaser operated at room temperature shows several distinct features including an extremely small mode volume down to 4.2x10 3l3, large Purcell factor of 20, and group index of 80, which ensures strong interaction with the exciton in the nanowire. Meanwhile, our current experimental results showed that the quality of metal play an important role in laser operation. In this report, I will also demonstrate the stable and low threshold lasing action by using metal grown by molecular beam epitaxy and dielectric layer by atomic layer deposition.", "author_names": [ "Tien-Chang Lu" ], "corpus_id": 8628373, "doc_id": "8628373", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Robust and ultracompact room temperature operated surface plasmon polariton nanolasers", "venue": "2016 Progress in Electromagnetic Research Symposium (PIERS)", "year": 2016 }, { "abstract": "Multi photon absorption pumped ultraviolet ZnO nanolasers were demonstrated with femtosecond pulses at room temperature. Time resolved photoluminescence revealed that the exciton collision effect played an important role in the nonlinear lasing mechanisms.", "author_names": [ "" ], "corpus_id": 29661766, "doc_id": "29661766", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Multi photon route to ultraviolet nanowire lasers", "venue": "2007 Quantum Electronics and Laser Science Conference", "year": 2007 }, { "abstract": "Multi photon absorption pumped ultraviolet ZnO nanolasers were demonstrated with femtosecond pulses at room temperature. Time resolved photoluminescence revealed that the exciton collision effect played an important role in the nonlinear lasing mechanisms.", "author_names": [ "Chunfeng Zhang", "Zhiwei Dong", "Kang-Jun Liu", "Guanjun You", "Shi-xiong Qian" ], "corpus_id": 122344025, "doc_id": "122344025", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Multi photon route to ultraviolet nanowire lasers", "venue": "QELS 2007", "year": 2007 }, { "abstract": "Nanolasers with an ultracompact footprint can provide high intensity coherent light, which can be potentially applied to high capacity signal processing, biosensing, and subwavelength imaging. Among various nanolasers, those with cavities surrounded by metals have been shown to have superior light emission properties because of the surface plasmon effect that provides enhanced field confinement capability and enables exotic light matter interaction. In this study, we demonstrated a robust ultraviolet ZnO nanolaser that can operate at room temperature by using silver to dramatically shrink the mode volume. The nanolaser shows several distinct features including an extremely small mode volume, a large Purcell factor, and a slow group velocity, which ensures strong interaction with the exciton in the nanowire.", "author_names": [ "Yu Hsun Chou", "Bo-Tsun Chou", "Chih-Kai Chiang", "Ying-Yu Lai", "C Yang", "Hong Li", "Tzy-Rong Lin", "Chien Chung Lin", "H C Kuo", "Shing-chung Wang", "Tien-Chang Lu" ], "corpus_id": 9374360, "doc_id": "9374360", "n_citations": 63, "n_key_citations": 1, "score": 0, "title": "Ultrastrong Mode Confinement in ZnO Surface Plasmon Nanolasers.", "venue": "ACS nano", "year": 2015 }, { "abstract": "Abstract. One dimensional compound semiconductor nanolasers, especially nanowire (NW) based nanolasers utilizing III nitride (AlGaInN) materials system, are an emerging and promising area of research. Significant achievements have been made in developing III nitride NW lasers with emission wavelengths from the deep ultraviolet (UV) to the near infrared spectral range. The types of lasers under investigation include Fabry Perot, photonic crystal, plasmonic, ring resonator, microstadium, random, polariton, and two dimensional distributed feedback lasers. The lasing thresholds vary by several orders of magnitude, which are a direct consequence of differing NW dimensions, quality of the NWs, characteristics of NW cavities, and coupling with the substrate. For electrically injected, such as ultralow threshold and continuous wave III nitride NW lasers that can operate at room temperature, the following obstacles remain: carrier loss mechanisms including defect related nonradiative surface recombination, electron overflow, and poor hole transport; low radiative recombination efficiency and high surface recombination; poor thermal management; and highly resistive ohmic contacts on the p layer. These obstacles must be overcome to fully realize the potential of these lasers.", "author_names": [ "Shamsul Arafin", "Xianhe Liu", "Zetian Mi" ], "corpus_id": 53050973, "doc_id": "53050973", "n_citations": 87, "n_key_citations": 1, "score": 0, "title": "Review of recent progress of III nitride nanowire lasers", "venue": "", "year": 2013 }, { "abstract": "Ultraviolet lasing from single zinc oxide nanowires is demonstrated at room temperature. Near field optical microscopy images quantify the localization and the divergence of the laser beam. The linewidths, wavelengths, and power dependence of the nanowire emission characterize the nanowire as an active optical cavity. These individual nanolasers could serve as miniaturized light sources for microanalysis, information storage, and optical computing.", "author_names": [ "Justin C Johnson", "Haoquan Yan", "Richard D Schaller", "Louis H Haber", "+ and Richard J Saykally", "Peidong Yang" ], "corpus_id": 197028121, "doc_id": "197028121", "n_citations": 356, "n_key_citations": 0, "score": 0, "title": "Single Nanowire Lasers", "venue": "", "year": 2001 }, { "abstract": "Rationally controlled growth of inorganic semiconductor nanowires is important for their applications in nanoscale electronics and photonics. In this article, we discuss the rational growth, physical properties, and integration of nanowires based on the results from the authors' laboratory. The composition, diameter, growth position, and orientation of the nanowires are controlled based on the vapor solid liquid (VLS) crystal growth mechanism. The thermal stability and optical properties of these semiconductor nanowires are investigated. Particularly, ZnO nanowires with well defined end surfaces can function as room temperature ultraviolet nanolasers. In addition, a novel microfluidic assisted nanowire integration (MANI) process was developed for the hierarchical assembly of nanowire building blocks into functional devices and systems.", "author_names": [ "Yiying Wu", "Haoquan Yan", "Michael Huang", "Benjamin M Messer", "Jae Hee Song", "Peidong Yang" ], "corpus_id": 17888920, "doc_id": "17888920", "n_citations": 376, "n_key_citations": 2, "score": 0, "title": "Inorganic semiconductor nanowires: rational growth, assembly, and novel properties.", "venue": "Chemistry", "year": 2002 } ]
Highly Efficient Multilevel Frequency Converters of Metallurgical Production Facilities
[ { "abstract": "A comparative analysis of traditional and multilevel low voltage frequency converters was performed. Calculation methods were proposed that make it possible to evaluate the technical and economic indices of multilevel semiconductor devices. The attractive qualities of low voltage multilevel frequency converters as compared with high voltage (with rated voltage exceeding 1 kV) multilevel semiconductor devices were distinguished. In low voltage multilevel converters, the loss in semiconductor rectifiers was reduced by about 1.5 times, the effect of overvoltage in the load was decreased, and the operating speed of the active rectifier was increased. A method of estimation of the loss in semiconductor converters with two level standalone inverters based on mathematical models and experimental studies is proposed, which made it possible to clarify the parameters of analytical equations. It is stated that using the three level bridge inverters (rectifiers) in active rectifiers makes it possible to shorten the durability of transient process of the system in the regeneration mode because of a reduced level of switching overvoltages. A method of choosing the optimal number of phases of semiconductor multilevel low voltage frequency converters for metallurgical production facilities according to the criterion of maximum probability of failure free operation was developed.", "author_names": [ "E S Chupin", "M A Grigor'ev" ], "corpus_id": 201243073, "doc_id": "201243073", "n_citations": 30, "n_key_citations": 0, "score": 1, "title": "Highly Efficient Multilevel Frequency Converters of Metallurgical Production Facilities", "venue": "Russian Electrical Engineering", "year": 2019 }, { "abstract": "A new method for analysing nonlinear and non stationary data has been developed. The key part of the method is the 'empirical mode decomposition' method with which any complicated data set can be decomposed into a finite and often small number of 'intrinsic mode functions' that admit well behaved Hilbert transforms. This decomposition method is adaptive, and, therefore, highly efficient. Since the decomposition is based on the local characteristic time scale of the data, it is applicable to nonlinear and non stationary processes. With the Hilbert transform, the 'instrinic mode functions' yield instantaneous frequencies as functions of time that give sharp identifications of imbedded structures. The final presentation of the results is an energy frequency time distribution, designated as the Hilbert spectrum. In this method, the main conceptual innovations are the introduction of 'intrinsic mode functions' based on local properties of the signal, which make the instantaneous frequency meaningful; and the introduction of the instantaneous frequencies for complicated data sets, which eliminate the need for spurious harmonics to represent nonlinear and non stationary signals. Examples from the numerical results of the classical nonlinear equation systems and data representing natural phenomena are given to demonstrate the power of this new method. Classical nonlinear system data are especially interesting, for they serve to illustrate the roles played by the nonlinear and non stationary effects in the energy frequency time distribution.", "author_names": [ "Norden E Huang", "Zheng Shen", "Steven R Long", "Manli C Wu", "Hsing H Shih", "Quan Zheng", "Nai-chyuan Yen", "Chi Chao Tung", "Henry H Liu" ], "corpus_id": 1262186, "doc_id": "1262186", "n_citations": 15804, "n_key_citations": 1785, "score": 0, "title": "The empirical mode decomposition and the Hilbert spectrum for nonlinear and non stationary time series analysis", "venue": "Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences", "year": 1998 }, { "abstract": "We propose a generative model for text and other collections of discrete data that generalizes or improves on several previous models including naive Bayes/unigram, mixture of unigrams [6] and Hofmann's aspect model also known as probabilistic latent semantic indexing (pLSI) [3] In the context of text modeling, our model posits that each document is generated as a mixture of topics, where the continuous valued mixture proportions are distributed as a latent Dirichlet random variable. Inference and learning are carried out efficiently via variational algorithms. We present empirical results on applications of this model to problems in text modeling, collaborative filtering, and text classification.", "author_names": [ "David M Blei", "A Ng", "Michael I Jordan" ], "corpus_id": 3177797, "doc_id": "3177797", "n_citations": 29031, "n_key_citations": 5603, "score": 0, "title": "Latent Dirichlet Allocation", "venue": "J. Mach. Learn. Res.", "year": 2003 }, { "abstract": "This chapter provides an overview of Analytic Hierarchy Process (AHP) which is a systematic procedure for representing the elements of any problem hierarchically. It organizes the basic rationality by breaking down a problem into its smaller constituent parts and then guides decision makers through a series of pair wise comparison judgments to express the relative strength or intensity of impact of the elements in the hierarchy. These judgments are then translated to numbers. The AHP includes procedures and principles used to synthesize the many judgments to derive priorities among criteria and subsequently for alternative solutions. It is useful to note that the numbers thus obtained are ratio scale estimates and correspond to so called hard numbers. Problem solving is a process of setting priorities in steps. One step decides on the most important elements of a problem, another on how best to repair, replace, test, and evaluate the elements, and another on how to implement the solution and measure performance.", "author_names": [ "Thomas L Saaty", "Kevin P Kearns" ], "corpus_id": 124731955, "doc_id": "124731955", "n_citations": 13693, "n_key_citations": 1157, "score": 0, "title": "The Analytic Hierarchy Process", "venue": "", "year": 1985 }, { "abstract": "1. Introduction to Predictive Control. 2. A Standard Formulation of Predictive Control. 3. Solving Predictive Control Problems. 4. Step Response and Transfer Function Formulations. 5. Tuning. 6. Stability. 7. Robust Predictive Control. 8. Perspectives. 9. Case Studies. 10. The Model Predictive Control Toolbox. References Appendices A. Some Commercial MPC Products B. MATLAB Program basicmpc C. The MPC Toolbox D. Solutions to Problems", "author_names": [ "Jan M Maciejowski" ], "corpus_id": 61138077, "doc_id": "61138077", "n_citations": 5322, "n_key_citations": 564, "score": 0, "title": "Predictive control with constraints", "venue": "", "year": 2002 }, { "abstract": "Understand the need for analyses of large, complex, information rich data sets. Identify the goals and primary tasks of the data mining process. Describe the roots of data mining technology. Recognize the iterative character of a data mining process and specify its basic steps. Explain the influence of data quality on a data mining process. Establish the relation between data warehousing and data mining. Data mining is an iterative process within which progress is defined by discovery, through either automatic or manual methods. Data mining is most useful in an exploratory analysis scenario in which there are no predetermined notions about what will constitute an \"interesting\" outcome. Data mining is the search for new, valuable, and nontrivial information in large volumes of data. It is a cooperative effort of humans and computers. Best results are achieved by balancing the knowledge of human experts in describing problems and goals with the search capabilities of computers. In practice, the two primary goals of data mining tend to be prediction and description. Prediction involves using some variables or fields in the data set to predict unknown or future values of other variables of interest. Description, on the other hand, focuses on finding patterns describing the data that can be interpreted by humans. Therefore, it is possible to put data mining activities into one of two categories: Predictive data mining, which produces the model of the system described by the given data set, or Descriptive data mining, which produces new, nontrivial information based on the available data set.", "author_names": [ "S Gnanapriya", "R Suganya", "Gagan Devi", "M Suresh Kumar" ], "corpus_id": 57146809, "doc_id": "57146809", "n_citations": 5725, "n_key_citations": 833, "score": 0, "title": "Data Mining Concepts and Techniques", "venue": "", "year": 2010 }, { "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": "We investigate the dependence of the center of mass tomogram of a system with many degrees of freedom $N$ on the Planck constant \\hbar It is shown that to use the central limit theorem under taking the limit $N\\to \\infty one should keep the energy of the system to be constant. In the case, the resulting distribution is Gaussian if the initial distribution is a product of independent excited states of a quantum oscillator or even and odd coherent states either. Then, if one turns the Planck constant \\hbar \\to 0$ we get \\delta function associated with the distribution concentrated in zero with the probability equal to one.", "author_names": [ "Grigori G Amosov", "Vladimir I Man'ko" ], "corpus_id": 18098126, "doc_id": "18098126", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A use of the central limit theorem to obtain a classical limit for the center of mass tomogram", "venue": "", "year": 2009 }, { "abstract": "Abstract Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently those with short range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed memory parallel machine which allows for message passing of data between independently executing processors. The algorithms are tested on a standard Lennard Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840 node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.", "author_names": [ "Steven J Plimpton" ], "corpus_id": 15881414, "doc_id": "15881414", "n_citations": 25757, "n_key_citations": 729, "score": 0, "title": "Fast parallel algorithms for short range molecular dynamics", "venue": "", "year": 1993 }, { "abstract": "Preface. 1 Introduction to Optimization. 1.1 Introduction. 1.2 Historical Development. 1.3 Engineering Applications of Optimization. 1.4 Statement of an Optimization Problem. 1.5 Classification of Optimization Problems. 1.6 Optimization Techniques. 1.7 Engineering Optimization Literature. 1.8 Solution of Optimization Problems Using MATLAB. References and Bibliography. Review Questions. Problems. 2 Classical Optimization Techniques. 2.1 Introduction. 2.2 Single Variable Optimization. 2.3 Multivariable Optimization with No Constraints. 2.4 Multivariable Optimization with Equality Constraints. 2.5 Multivariable Optimization with Inequality Constraints. 2.6 Convex Programming Problem. References and Bibliography. Review Questions. Problems. 3 Linear Programming I: Simplex Method. 3.1 Introduction. 3.2 Applications of Linear Programming. 3.3 Standard Form of a Linear Programming Problem. 3.4 Geometry of Linear Programming Problems. 3.5 Definitions and Theorems. 3.6 Solution of a System of Linear Simultaneous Equations. 3.7 Pivotal Reduction of a General System of Equations. 3.8 Motivation of the Simplex Method. 3.9 Simplex Algorithm. 3.10 Two Phases of the Simplex Method. 3.11 MATLAB Solution of LP Problems. References and Bibliography. Review Questions. Problems. 4 Linear Programming II: Additional Topics and Extensions. 4.1 Introduction. 4.2 Revised Simplex Method. 4.3 Duality in Linear Programming. 4.4 Decomposition Principle. 4.5 Sensitivity or Postoptimality Analysis. 4.6 Transportation Problem. 4.7 Karmarkar's Interior Method. 4.8 Quadratic Programming. 4.9 MATLAB Solutions. References and Bibliography. Review Questions. Problems. 5 Nonlinear Programming I: One Dimensional Minimization Methods. 5.1 Introduction. 5.2 Unimodal Function. ELIMINATION METHODS. 5.3 Unrestricted Search. 5.4 Exhaustive Search. 5.5 Dichotomous Search. 5.6 Interval Halving Method. 5.7 Fibonacci Method. 5.8 Golden Section Method. 5.9 Comparison of Elimination Methods. INTERPOLATION METHODS. 5.10 Quadratic Interpolation Method. 5.11 Cubic Interpolation Method. 5.12 Direct Root Methods. 5.13 Practical Considerations. 5.14 MATLAB Solution of One Dimensional Minimization Problems. References and Bibliography. Review Questions. Problems. 6 Nonlinear Programming II: Unconstrained Optimization Techniques. 6.1 Introduction. DIRECT SEARCH METHODS. 6.2 Random Search Methods. 6.3 Grid Search Method. 6.4 Univariate Method. 6.5 Pattern Directions. 6.6 Powell's Method. 6.7 Simplex Method. INDIRECT SEARCH (DESCENT) METHODS. 6.8 Gradient of a Function. 6.9 Steepest Descent (Cauchy) Method. 6.10 Conjugate Gradient (Fletcher Reeves) Method. 6.11 Newton's Method. 6.12 Marquardt Method. 6.13 Quasi Newton Methods. 6.14 Davidon Fletcher Powell Method. 6.15 Broyden Fletcher Goldfarb Shanno Method. 6.16 Test Functions. 6.17 MATLAB Solution of Unconstrained Optimization Problems. References and Bibliography. Review Questions. Problems. 7 Nonlinear Programming III: Constrained Optimization Techniques. 7.1 Introduction. 7.2 Characteristics of a Constrained Problem. DIRECT METHODS. 7.3 Random Search Methods. 7.4 Complex Method. 7.5 Sequential Linear Programming. 7.6 Basic Approach in the Methods of Feasible Directions. 7.7 Zoutendijk's Method of Feasible Directions. 7.8 Rosen's Gradient Projection Method. 7.9 Generalized Reduced Gradient Method. 7.10 Sequential Quadratic Programming. INDIRECT METHODS. 7.11 Transformation Techniques. 7.12 Basic Approach of the Penalty Function Method. 7.13 Interior Penalty Function Method. 7.14 Convex Programming Problem. 7.15 Exterior Penalty Function Method. 7.16 Extrapolation Techniques in the Interior Penalty Function Method. 7.17 Extended Interior Penalty Function Methods. 7.18 Penalty Function Method for Problems with Mixed Equality and Inequality Constraints. 7.19 Penalty Function Method for Parametric Constraints. 7.20 Augmented Lagrange Multiplier Method. 7.21 Checking the Convergence of Constrained Optimization Problems. 7.22 Test Problems. 7.23 MATLAB Solution of Constrained Optimization Problems. References and Bibliography. Review Questions. Problems. 8 Geometric Programming. 8.1 Introduction. 8.2 Posynomial. 8.3 Unconstrained Minimization Problem. 8.4 Solution of an Unconstrained Geometric Programming Program Using Differential Calculus. 8.5 Solution of an Unconstrained Geometric Programming Problem Using Arithmetic Geometric Inequality. 8.6 Primal Dual Relationship and Sufficiency Conditions in the Unconstrained Case. 8.7 Constrained Minimization. 8.8 Solution of a Constrained Geometric Programming Problem. 8.9 Primal and Dual Programs in the Case of Less Than Inequalities. 8.10 Geometric Programming with Mixed Inequality Constraints. 8.11 Complementary Geometric Programming. 8.12 Applications of Geometric Programming. References and Bibliography. Review Questions. Problems. 9 Dynamic Programming. 9.1 Introduction. 9.2 Multistage Decision Processes. 9.3 Concept of Suboptimization and Principle of Optimality. 9.4 Computational Procedure in Dynamic Programming. 9.5 Example Illustrating the Calculus Method of Solution. 9.6 Example Illustrating the Tabular Method of Solution. 9.7 Conversion of a Final Value Problem into an Initial Value Problem. 9.8 Linear Programming as a Case of Dynamic Programming. 9.9 Continuous Dynamic Programming. 9.10 Additional Applications. References and Bibliography. Review Questions. Problems. 10 Integer Programming. 10.1 Introduction 588. INTEGER LINEAR PROGRAMMING. 10.2 Graphical Representation. 10.3 Gomory's Cutting Plane Method. 10.4 Balas' Algorithm for Zero One Programming Problems. INTEGER NONLINEAR PROGRAMMING. 10.5 Integer Polynomial Programming. 10.6 Branch and Bound Method. 10.7 Sequential Linear Discrete Programming. 10.8 Generalized Penalty Function Method. 10.9 Solution of Binary Programming Problems Using MATLAB. References and Bibliography. Review Questions. Problems. 11 Stochastic Programming. 11.1 Introduction. 11.2 Basic Concepts of Probability Theory. 11.3 Stochastic Linear Programming. 11.4 Stochastic Nonlinear Programming. 11.5 Stochastic Geometric Programming. References and Bibliography. Review Questions. Problems. 12 Optimal Control and Optimality Criteria Methods. 12.1 Introduction. 12.2 Calculus of Variations. 12.3 Optimal Control Theory. 12.4 Optimality Criteria Methods. References and Bibliography. Review Questions. Problems. 13 Modern Methods of Optimization. 13.1 Introduction. 13.2 Genetic Algorithms. 13.3 Simulated Annealing. 13.4 Particle Swarm Optimization. 13.5 Ant Colony Optimization. 13.6 Optimization of Fuzzy Systems. 13.7 Neural Network Based Optimization. References and Bibliography. Review Questions. Problems. 14 Practical Aspects of Optimization. 14.1 Introduction. 14.2 Reduction of Size of an Optimization Problem. 14.3 Fast Reanalysis Techniques. 14.4 Derivatives of Static Displacements and Stresses. 14.5 Derivatives of Eigenvalues and Eigenvectors. 14.6 Derivatives of Transient Response. 14.7 Sensitivity of Optimum Solution to Problem Parameters. 14.8 Multilevel Optimization. 14.9 Parallel Processing. 14.10 Multiobjective Optimization. 14.11 Solution of Multiobjective Problems Using MATLAB. References and Bibliography. Review Questions. Problems. A Convex and Concave Functions. B Some Computational Aspects of Optimization. B.1 Choice of Method. B.2 Comparison of Unconstrained Methods. B.3 Comparison of Constrained Methods. B.4 Availability of Computer Programs. B.5 Scaling of Design Variables and Constraints. B.6 Computer Programs for Modern Methods of Optimization. References and Bibliography. C Introduction to MATLAB(R) C.1 Features and Special Characters. C.2 Defining Matrices in MATLAB. C.3 CREATING m FILES. C.4 Optimization Toolbox. Answers to Selected Problems. Index", "author_names": [ "Singiresu S Rao" ], "corpus_id": 117278413, "doc_id": "117278413", "n_citations": 3041, "n_key_citations": 203, "score": 0, "title": "Engineering Optimization Theory and Practice", "venue": "", "year": 2010 } ]
Spin Filtering through Chiral Molecules on Semiconductors
[ { "abstract": "", "author_names": [ "Tianhan Liu", "Longqian Hu", "Eric J Lochner", "Xiao-Lei Wang", "Hailong Wang", "Gang Shi", "Fan Gao", "Honglei Feng", "Yongqing Li", "Jianhua Zhao", "Peng Xiong" ], "corpus_id": 181938644, "doc_id": "181938644", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Spin Filtering through Chiral Molecules on Semiconductors", "venue": "", "year": 2019 }, { "abstract": "Recent experiments have demonstrated that the electron transmission yield through chiral molecules depends on the electron spin orientation. This phenomenon has been termed the chiral induced spin selectivity (CISS) effect, and it provides a challenge to theory and promise for organic molecule based spintronic devices. This article reviews recent developments in our understanding of CISS. Different theoretical models have been used to describe the effect; however, they all presume an unusually large spin orbit coupling in chiral molecules for the effect to display the magnitudes seen in experiments. A simplified model for an electron's transport through a chiral potential suggests that these large couplings can be manifested. Techniques for measuring spin selective electron transport through molecules are overviewed, and some examples of recent experiments are described. Finally, we present results obtained by studying several systems, and we describe the possible application of the CISS effect for memory devices.", "author_names": [ "Ron Naaman", "David H Waldeck" ], "corpus_id": 207631669, "doc_id": "207631669", "n_citations": 200, "n_key_citations": 3, "score": 0, "title": "Spintronics and chirality: spin selectivity in electron transport through chiral molecules.", "venue": "Annual review of physical chemistry", "year": 2015 }, { "abstract": "Density of States function, g(E) Fermi Dirac Distribution function, f(E) Distribution Function and Fermi Energy Equilibrium Distribution of Electrons and Holes n0 and p0 Equation Intrinsic carrier concentration Fermi level for Intrinsic Semiconductor Extrinsic Semiconductor Position of the Fermi Level of the Extrinsic Semiconductor Non Degenerated Semiconductor Variation of EF with Doping Concentration and with Temperature Compensated Semiconductor Statistics of donors and acceptors Formula to remember Question Bank Solved problems Assignment", "author_names": [ "S M Sze" ], "corpus_id": 171088339, "doc_id": "171088339", "n_citations": 3756, "n_key_citations": 590, "score": 0, "title": "PHYSICS OF SEMICONDUCTOR DEVICES", "venue": "", "year": 2007 }, { "abstract": "Understanding the origin of chirality in nature has been an active area of research since the time of Pasteur. In this chapter we examine one possible route by which this asymmetry could have arisen, namely chiral specific chemistry induced by spin polarized electrons. The various sources of spin polarized electrons (parity violation, photoemission, and secondary processes) are discussed. Experiments aimed at exploring these interactions are reviewed starting with those based on the Vester Ulbricht hypothesis through recent studies of spin polarized secondary electrons from a magnetic substrate. We will conclude with a discussion of possible new avenues of research that could impact this area.", "author_names": [ "Richard A Rosenberg" ], "corpus_id": 36721231, "doc_id": "36721231", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Spin polarized electron induced asymmetric reactions in chiral molecules.", "venue": "Topics in current chemistry", "year": 2011 }, { "abstract": "Electron transmission through chiral molecules induced by circularly polarized light can be very different for mirror image structures, a peculiar fact given that the electronic energy spectra of the systems are identical. We propose that this asymmetry as large as 10% for resonant transport arises from different dynamical responses of the mirrored structures to coherent excitation. This behavior is described in the context of a general novel phenomenon of current transfer (transfer of charge with its momentum information) and accounts for the observed asymmetry and its dependence on structure.", "author_names": [ "Spiros S Skourtis", "David N Beratan", "Ron Naaman", "Abraham Nitzan", "David H Waldeck" ], "corpus_id": 24757714, "doc_id": "24757714", "n_citations": 36, "n_key_citations": 0, "score": 0, "title": "Chiral control of electron transmission through molecules.", "venue": "Physical review letters", "year": 2008 }, { "abstract": "The functionality of many biological systems depends on reliable electron transfer with minimal heating. Unlike man made electric circuits, nature realizes electron transport via insulating chiral molecules. Here we include spin into the analysis of tunneling through these molecules, and demonstrate its importance for efficient transport. We show that the helical geometry induces robust spin filtering accompanied by, and intimately related to, strongly enhanced transmission. Thus, we resolve two key questions posed by transport measurements through organic molecules, demonstrating their common origin.", "author_names": [ "Karen Michaeli", "Ron Naaman" ], "corpus_id": 118525363, "doc_id": "118525363", "n_citations": 46, "n_key_citations": 0, "score": 0, "title": "Origin of Spin Dependent Tunneling Through Chiral Molecules", "venue": "The Journal of Physical Chemistry C", "year": 2019 }, { "abstract": "The ultimate aim of any detection method is to achieve such a level of sensitivity that individual quanta of a measured entity can be resolved. In the case of chemical sensors, the quantum is one atom or molecule. Such resolution has so far been beyond the reach of any detection technique, including solid state gas sensors hailed for their exceptional sensitivity. The fundamental reason limiting the resolution of such sensors is fluctuations due to thermal motion of charges and defects, which lead to intrinsic noise exceeding the sought after signal from individual molecules, usually by many orders of magnitude. Here, we show that micrometre size sensors made from graphene are capable of detecting individual events when a gas molecule attaches to or detaches from graphene's surface. The adsorbed molecules change the local carrier concentration in graphene one by one electron, which leads to step like changes in resistance. The achieved sensitivity is due to the fact that graphene is an exceptionally low noise material electronically, which makes it a promising candidate not only for chemical detectors but also for other applications where local probes sensitive to external charge, magnetic field or mechanical strain are required.", "author_names": [ "Fred Schedin", "Andre K Geim", "S V Morozov", "Ernie W Hill", "Peter Blake", "Mikhail I Katsnelson", "Kostya S Novoselov" ], "corpus_id": 3518448, "doc_id": "3518448", "n_citations": 6217, "n_key_citations": 53, "score": 0, "title": "Detection of individual gas molecules adsorbed on graphene.", "venue": "Nature materials", "year": 2007 }, { "abstract": "Conspectus Molecular spintronics (spin electronics) which aims to exploit both the spin degree of freedom and the electron charge in molecular devices, has recently received massive attention. Our recent experiments on molecular spintronics employ chiral molecules which have the unexpected property of acting as spin filters, by way of an effect we call \"chiral induced spin selectivity\" (CISS) In this Account, we discuss new types of spin dependent electrochemistry measurements and their use to probe the spin dependent charge transport properties of nonmagnetic chiral conductive polymers and biomolecules, such as oligopeptides, L/D cysteine, cytochrome c, bacteriorhodopsin (bR) and oligopeptide CdSe nanoparticles (NPs) hybrid structures. Spin dependent electrochemical measurements were carried out by employing ferromagnetic electrodes modified with chiral molecules used as the working electrode. Redox probes were used either in solution or when directly attached to the ferromagnetic electrodes. During the electrochemical measurements, the ferromagnetic electrode was magnetized either with its magnetic moment pointing \"UP\" or \"DOWN\" using a permanent magnet (H 0.5 T) placed underneath the chemically modified ferromagnetic electrodes. The spin polarization of the current was found to be in the range of 5 30% even in the case of small chiral molecules. Chiral films of the l and d cysteine tethered with a redox active dye, toludin blue O, show spin polarizarion that depends on the chirality. Because the nickel electrodes are susceptible to corrosion, we explored the effect of coating them with a thin gold overlayer. The effect of the gold layer on the spin polarization of the electrons ejected from the electrode was investigated. In addition, the role of the structure of the protein on the spin selective transport was also studied as a function of bias voltage and the effect of protein denaturation was revealed. In addition to \"dark\" measurements, we also describe photoelectrochemical measurements in which light is used to affect the spin selective electron transport through the chiral molecules. We describe how the excitation of a chromophore (such as CdSe nanoparticles) which is attached to a chiral working electrode, can flip the preferred spin orientation of the photocurrent, when measured under the identical conditions. Thus, chirality induced spin polarization, when combined with light and magnetic field effects, opens new avenues for the study of the spin transport properties of chiral molecules and biomolecules and for creating new types of spintronic devices in which light and molecular chirality provide new functions and properties.", "author_names": [ "Prakash Chandra Mondal", "Claudio Fontanesi", "David H Waldeck", "Ron Naaman" ], "corpus_id": 2894380, "doc_id": "2894380", "n_citations": 80, "n_key_citations": 0, "score": 0, "title": "Spin Dependent Transport through Chiral Molecules Studied by Spin Dependent Electrochemistry", "venue": "Accounts of chemical research", "year": 2016 }, { "abstract": "The electron's spin is essential to the stability of matter, and control over the spin opens up avenues for manipulating the properties of molecules and materials. The Pauli exclusion principle requires that two electrons in a single spatial eigenstate have opposite spins, and this fact dictates basic features of atomic states and chemical bond formation. The energy associated with interacting electron clouds changes with their relative spin orientation, and by manipulating the spin directions, one can guide chemical transformations. However, controlling the relative spin orientation of electrons located on two reactants (atoms, molecules or surfaces) has proved challenging. Recent developments based on the chiral induced spin selectivity (CISS) effect show that the spin orientation is linked to molecular symmetry and can be controlled in ways not previously imagined. For example, the combination of chiral molecules and electron spin opens up a new approach to (enantio)selective chemistry. This Review describes the theoretical concepts underlying the CISS effect and illustrates its importance by discussing some of its manifestations in chemistry, biology and physics. Specifically, we discuss how the CISS effect allows for efficient long range electron transfer in chiral molecules and how it affects biorecognition processes. Several applications of the effect are presented, and the importance of controlling relative spin orientations in multi electron processes, such as electrochemical water splitting, is emphasized. We describe the enantiospecific interaction between ferromagnetic substrates and chiral molecules and how it enables the separation of enantiomers with ferromagnets. Lastly, we discuss the relevance of CISS effects to biological electron transfer, enantioselectivity and CISS based spintronics applications.Chiral molecules can filter electrons according to their spin. This chiral induced spin selectivity (CISS) effect can have important applications, such as in spintronics and in enantioseparation. This Review describes the CISS effect, its mechanism and its fascinating applications.", "author_names": [ "Ron Naaman", "Yossi Paltiel", "David H Waldeck" ], "corpus_id": 128149437, "doc_id": "128149437", "n_citations": 139, "n_key_citations": 3, "score": 0, "title": "Chiral molecules and the electron spin", "venue": "Nature Reviews Chemistry", "year": 2019 }, { "abstract": "Recent experiments have demonstrated the efficacy of chiral helically shaped molecules in polarizing the scattered electron spin, an effect termed as chiral induced spin selectivity (CISS) Here we solve a simple tight binding model for electron transport through a single helical molecule, with spin orbit interactions on the bonds along the helix. Quantum interference is introduced via additional electron hopping between neighboring sites in the direction of the helix axis. When the helix is connected to two one dimensional single mode leads, time reversal symmetry prevents spin polarization of the outgoing electrons. One possible way to retrieve such a polarization is to allow leakage of electrons from the helix to the environment, via additional outgoing leads. Technically, the leakage generates complex site self energies, which break unitarity. As a result, the electron waves in the helix become evanescent, with different decay lengths for different spin polarizations, yielding a net spin polarization of the outgoing electrons, which increases with the length of the helix (as observed experimentally) A maximal polarization can be measured at a finite angle away from the helix axis.", "author_names": [ "Shlomi Matityahu", "Yasuhiro Utsumi", "Amnon Aharony", "O Entin-wohlman", "C A Balseiro" ], "corpus_id": 119302973, "doc_id": "119302973", "n_citations": 58, "n_key_citations": 1, "score": 0, "title": "Spin dependent transport through a chiral molecule in the presence of spin orbit interaction and nonunitary effects", "venue": "", "year": 2016 } ]
Organic electronics: materials, manufacturing, and applications
[ { "abstract": "I. MATERIALS High performance Organic Semiconductor Materials Ian McCulloch (Imperial College, London) Electroactive Polymer Thin Films Dean DeLongchamp (NIST) Materials for Large area Electronics Alberto Salleo (Stanford University) Functional Pentacenes John Anthony (University of Kentucky) Plastic Electronics Antonio Facchetti (Northwestern University, Polyera) Electronic, Photonic and Magnetic Materials Dan Frisbie (University of Minnesota) II. MANUFACTURING Printing Technology Vivek Subramanian (University of California, Berkeley) Solution Processing Ana Claudia Arias (Palo Alto Research Center) Direct Inkjet Printing Takao Someya (University of Tokyo) Photoresist free Patterning Tom Jackson (Pennsylvania State University) III. APPLICATIONS Photonic Nanostructures Jana Zaumseil (Argonne National Laboratory) Plastic Transistors Henning Sirringhaus (Plastic Logic) Integrated Microsystems Eugenio Cantatore (Eindhoven University of Technology) Active Matrix Displays Kazumasa Nomoto (SONY)", "author_names": [ "Hagen Klauk" ], "corpus_id": 107654987, "doc_id": "107654987", "n_citations": 709, "n_key_citations": 14, "score": 1, "title": "Organic electronics materials, manufacturing and applications", "venue": "", "year": 2006 }, { "abstract": "", "author_names": [ "Derck Schlettwein" ], "corpus_id": 94872592, "doc_id": "94872592", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Organic Electronics Materials, Manufacturing and Applications. Edited by Hagen Klauk.", "venue": "", "year": 2007 }, { "abstract": "", "author_names": [ "Antonio F Facchetti" ], "corpus_id": 98055885, "doc_id": "98055885", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Organic Electronics. Materials, Manufacturing and Applications. Edited by Hagen Klauk.", "venue": "", "year": 2007 }, { "abstract": "", "author_names": [ "Antonio F Facchetti" ], "corpus_id": 97736144, "doc_id": "97736144", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Organic Electronics. Materials, Manufacturing and Applications. Herausgegeben von Hagen Klauk.", "venue": "", "year": 2007 }, { "abstract": "", "author_names": [ "Patrick R L Malenfant" ], "corpus_id": 137025783, "doc_id": "137025783", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Book Review: Organic Electronics. Materials, Manufacturing And Applications. By Hagen Klauk (Ed.", "venue": "", "year": 2007 }, { "abstract": "Organic electronics is thriving. Organic light emitting diodes (OLEDs) can be found in products ranging from cell phone displays to high end televisions, organic photovoltaics are close to being commercially viable, and even flexible organic electronic devices are on the horizon. Compared to conventional inorganic electronic materials, organic materials offer a number of advantages such as being light weight and mechanically flexible, which makes them ideal for flexible electronic applications [1,2] Furthermore, synthetic chemistry techniques can be used to create molecules with specific electrical or optical properties. Organic, or plastic, electronic devices can also be fabricated by using inexpensive techniques such as roll to roll processing [3] which are cheaper and far less complex than the techniques used in the manufacturing of state of the art silicon integrated circuits. As a result, organic electronics are typically only associated with relatively low cost, large area or disposable electronic applications, such as flatpanel displays, sensor arrays, smart cards, and radio frequency identification (RFID) tags [4] Writing in Nature Electronics, Deepak Venkateshvaran, Henning Sirringhaus and colleagues now show that certain organic materials also have fundamental properties that make them ideal for high value spintronics applications [5]", "author_names": [ "Curt A Richter", "Emily G Bittle" ], "corpus_id": 199569954, "doc_id": "199569954", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Dopants give organic electronics a new spin Standfirst: Electron spins can travel long distances in heavily doped organic materials", "venue": "", "year": 2019 }, { "abstract": "While much research in the field of conducting polymers and organic electronics focuses on development of novel polymers and other related materials, or enhancing the properties of existing materials and understanding the mechanisms behind them, in many cases, clear and reliable future directions or applications of the research are unclear. Developing an understanding of the roles of different physical and chemical mechanisms and establishing simple, cheap and reliable manufacturing and processing technologies for conducting polymers will be crucial to guide future research to uncover modern materials for advanced practical applications. In the present work, several novel manufacturing and processing routes have been established to firstly create organic materials with desired properties and, later, to apply them in functional devices. Several adjustments have been made to the synthesis of conducting polymers, and novel ways for patterning of thin organic films developed, so that high quality materials can be made cheaply and relatively quickly and then used to create functional devices with improved properties. Conducting polymers such as polyacetylene, polythiophene, polyaniline or poly(3,4 ethylenedioxythiophene) have been studied for several decades now; however, their properties have not been sufficient for widespread commercial application. Only recently have developments in the field and improvements in the properties of these materials, as well as better understanding of mechanisms underlying their functionality, allowed their use in prototype devices. The conductivity of organic materials is still relatively low compared to that of their inorganic counterparts, although some applications do not require such high electrical properties. A critical step was to better understand conductivity mechanisms and improve them using several different methods. Examples of methods to improve properties include blending two or more conducting or non conducting polymers, co polymerizing different monomers together or designing polymers and their surfaces on the nano level. This work presents a study of two conducting polymers: poly(3,4 ethylenedioxythiophene) and poly(thiophene) and some attempts to increase their current properties or develop new properties to meet requirements for specific applications. Most of the effort focuses on the development of properties that are important for application in fields like energy production and storage, photonics and electronics. These critical properties include high electrical performance and high conductivity, good electrochemical properties, high surface area, broad light absorption spectra, biocompatibility, good mechanical properties and long lifetime. Chapter 3 discusses vapor phase co polymerization of bithiophene and terthiophene as a route to widen absorption spectra of polythiophene materials. Chapter 4 describes processes responsible for formation of polythiophene nano structures during vapor phase polymerization. It also explains conditions and polymerization parameters responsible for formation of different nano structures so that those materials can be tuned for desired applications. Chapter 5 shows development of a laser ablation technique as a way to pattern conducting polymers to get the shape and architecture required for a specific device or application. The laser ablation technique is applied to manufacture organic electrochemical transistors and gas sensors. Lastly, Chapter 6 builds on knowledge from previous chapters to develop organic light sensors and opto logic gates that can be used in an optical to electronic interface. This work significantly advances the state of knowledge of conducting polymers within the organic electronics field, and gives insights into how those materials interact with each other and how to tailor their properties. The findings here can serve as a basis for developing new conducting polymers, as well as direct investigations for new applications using the materials presented here.", "author_names": [ "Bartlomiej Piotr Kolodziejczyk" ], "corpus_id": 137998157, "doc_id": "137998157", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Development of novel conjugated polymer materials and structures for organic electronics and energy applications", "venue": "", "year": 2015 }, { "abstract": "Plastic electronics has made great commercial and scientific progress over the past decade, predominantly driven by the potential of applications such as organic field effect transistors (OFETs) for flexible backplanes and e paper, organic light emitting diodes (OLEDs) for large area lighting and displays and organic solar cells (OPV) for large area energy generation.1,2 Much of this work has been motivated by the fact that organic semiconductors can combine the superb mechanical and processing characteristics of plastics with a variety of printing techniques, enabling large area, low cost manufacturing. There has been an intensive worldwide research effort on the development of stable, conjugated organic semiconducting polymers as potential replacements for conventional silicon, the benchmark large area amorphous semiconductor. ID TechEx, the UK based market research company, \"estimates that over the last two decades global investments into plastic electronics technologies exceed US $10 billion, and predict that this will grow to almost US $25 billion by 2020\".3 The ecological and commercial motivation to implement the use of plastic electronics is compelling. Recently, such efforts have facilitated the development of thin film transistors for backplane applications such as e paper. The ability to operate in ambient atmosphere without costly and rigorous encapsulation barriers to avoid water and/or oxygen is an important step towards commercialization. Research for cleaner alternatives of energy generation and advanced energy permitting devices has journeyed down an interesting path. The exploration of conjugated organic materials within the context of energy has led to the development of devices with great potential for utilization and exploitation within the near future, where perhaps the emergence of hybrid materials or the utilization of nano architectonics will be of paramount importance to aid in the development of state of the art nanotechnology and its utilization within energy related themes. Meanwhile, further reducing of the cost is expected in the next decade as a result of designing next generation of energy devices (e.g. supercapacitors, solar cells, Li ion batteries, fuel cells) Organic PV active layers (especially polymer based materials) have the latent potential of solution based processing of the active layers, offering the attraction of low cost, continuous roll to roll or printing processing of large area devices upon flexible substrates. These deposition techniques of the active layers may allow devices to meet the $15/m2 target; for comparison paint costs about $1/m2. Furthermore, organic active layers offer infinite design space by virtue of the polymer architectures, providing potential for layers design and tunability to suit specific energy supply criteria.4 The development of more efficient energy producing devices and cleaner energy generation alternatives continue to advance. The investigation of polymeric materials within the context of solar energy has thus far yielded devices with great potential. Through systematic chemical modification, the performance of OPV cells has advanced impressively over the last three years, with power conversion efficiency (PCE) now routinely surpassing 8% and attracting industrial interest in commercializing this technology.5 The synthesis of well defined conjugated molecules/polymers is a considerable synthetic challenge that many excellent research groups have addressed over the last decade or so. A particularly promising class of potential donor/acceptor materials for use in BHJ solar cells and organic electronics are the aromatic donor acceptor amido pigments diketopyrrolopyrrole (DPP) and isoindigo and the electron deficient bis Thiazole (Figure 1) Here, an electron rich aromatic segment is positioned adjacent to a highly electron deficient amide link typically known as a push pull chromophore.6 When incorporated into small molecules or polymers, this structure affords very narrow band gaps capable of harvesting a large percentage of the solar flux. Both DPP and isoindigo units have recently been used to construct some of the most efficient organic solar cells to date, and the present work capitalizes on these advances, and goes beyond. Figure 1 Chemical structures of DPP, Isoindigo and bis thiazole. Here we will present our synthetic efforts on developing the novel polymeric materials containing the three structures shown in Figure 1, particular emphasis on a suit of carefully selected sidechains, which has provide access to a wide range of monomers with tuneable solubility (with either short or long, branched or linear alkyl chains) Moreover, the initial synthetic targets will specifically be the introduction of branched ocytyl decyl chains as well as linear hexadecyl alkyl chains since they have both been used in other high efficiency conjugated polymers the latter are known to enhance interchain interdigitation and close p p stacking. References: (1) Kim, Y. Cook, S. Tuladhar, S. M. Choulis, S. A. Nelson, J. Durrant, J. R. Bradley, D. D. C. Giles, M. Mcculloch, I. Ha, C. S. Ree, M. Nat Mater 2006, 5, 197. (2) Chen, H. Y. Hou, J. H. Zhang, S. Q. Liang, Y. Y. Yang, G. W. Yang, Y. Yu, L. P. Wu, Y. Li, G. Nat Photonics 2009, 3, 649. (3) http:/ukplaticelectronics.com, C. G. U. P. E. (4) Krebs, F. C. Gevorgyan, S. A. Alstrup, J. J. Mater. Chem. 2009, 19 (30) 5442 5451. (5) Guo, X. Zhou, N. Lou, S. J. Smith, J. Tice, D. B. Hennek, J. W. Ortiz, R. P. Navarrete, J. T. L. Li, S. Strzalka, J. Chen, L. X. Chang, R. P. H. Facchetti, A. Marks, T. J. Nat. Photon 2013, 7 (10) 825 833. (6) Li, Y. Sonar, P. Murphy, L. Hong, W. Energy Environ. Sci. 2013, 6 (6) 1684 1710. (7) Cates, N. C. Gysel, R. Beiley, Z. Miller, C. E. Toney, M. F. Heeney, M. McCulloch, I. McGehee, M. D. Nano Lett. 2009, 9 (12) 4153 4157.", "author_names": [ "Mohammed Al-Hashimi", "Hugo Bronstein", "Lei Fang", "Hassan S Bazzi", "Martin Heeney", "Tobin J Marks" ], "corpus_id": 138014894, "doc_id": "138014894", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "New Conjugated Polymer Materials for Solar Energy and Organic Electronics", "venue": "", "year": 2016 }, { "abstract": "Abstract Today's organic electronic devices, such as the highly successful OLED displays, are based on disordered films, with carrier mobilities orders of magnitude below those of inorganic semiconductors like silicon or GaAs. For organic devices such as diodes and transistors, higher charge carrier mobilities are paramount to achieve high performance. Organic single crystals have been shown to offer these required high mobilities. However, manufacturing and processing of these crystals are complex, rendering their use outside of laboratory scale applications negligible. Furthermore, doping cannot be easily integrated into these systems, which is particularly problematic for devices mandating high mobility materials. Here, it is demonstrated for the model system rubrene that highly ordered, doped thin films can be prepared, allowing high performance organic devices on almost any substrate. Specifically, triclinic rubrene crystals are created by abrupt heating of amorphous layers and can be electrically doped during the epitaxial growth process to achieve hole or electron conduction. Analysis of the space charge limited current in these films reveals record vertical mobilities of 10.3(49) cm2 V 1 s 1. To demonstrate the performance of this materials system, monolithic pin diodes aimed for rectification are built. The f3db of these diodes is over 1 GHz and thus higher than any other organic semiconductor based device shown so far. It is believed that this work will pave the way for future high performance organic devices based on highly crystalline thin films.", "author_names": [ "Michael F Sawatzki", "Hans Kleemann", "Bahman Kheradmand Boroujeni", "Shu-Jen Wang", "Joern Vahland", "Frank Ellinger", "Karl Leo" ], "corpus_id": 232292751, "doc_id": "232292751", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Doped Highly Crystalline Organic Films: Toward High Performance Organic Electronics", "venue": "Advanced science", "year": 2021 }, { "abstract": "Transient electronics represents recent technology that can partially or completely degrade, dissolve, or disintegrate under certain conditions in actively and passively controlled ways. They offer applications as eco friendly alternatives to existing electronic components, implantable biomedical devices, and software/hardware protection systems. The degradable characteristics of materials and circuits, however, lead to various fabrication issues and difficulties in manufacturing complex systems requiring fine and elaborate design layouts and microfabrication procedures under thermally and chemically harsh conditions. Identifying advanced materials and the development of manufacturing processes compatible with established transient materials have been conducted for several years to address these issues. In this article, we focus on recent trends in manufacturing technologies for transient electronic systems, including direct fabrication of electronics on transient substrates using organic inorganic electronic materials, screen printing approaches particularly for conductive traces, microfabrication combined with multiple transfer printing techniques, and large scale, foundry compatible technologies.", "author_names": [ "Won Bae Han", "Gwan-Jin Ko", "Jeong-Woong Shin", "Suk-Won Hwang" ], "corpus_id": 213993440, "doc_id": "213993440", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Advanced manufacturing for transient electronics", "venue": "", "year": 2020 } ]
Power Cycling Reliability of Power Module: A Survey
[ { "abstract": "Electronic devices using semiconductors such as insulated gate bipolar transistors, metal oxide semiconductor field effect transistors, and diodes are extensively used in electrical traction applications such as locomotive, elevators, subways, and cars. The long term reliability of such power modules is then highly demanded, and their main reliability criterion is their power cycling capability. Thus, a power cycling test is the most important reliability test for power modules. This test consists in periodically applying a current to a device mounted onto a heat sink. This leads to power loss in the entire module and results in a rise in the semiconductor temperature. In this paper, the different kinds of semiconductors and power modules used for traction applications are described. Experimental and simulation methods employed for power cycling tests are presented. Modules' weak points and fatigue processes are pointed out. Then, a detailed statistical review of publications from 1994 to 2015 dealing with power cycling is presented. This review gives a clear overview of all studies dealing with power cycling that were carried out until now. It reveals the principal trends in power electronic devices and highlights the main reliability issues for which an important lack of knowledge remains.", "author_names": [ "C Durand", "Markus Klingler", "Daniel Coutellier", "Hakim Naceur" ], "corpus_id": 35234033, "doc_id": "35234033", "n_citations": 91, "n_key_citations": 7, "score": 1, "title": "Power Cycling Reliability of Power Module: A Survey", "venue": "IEEE Transactions on Device and Materials Reliability", "year": 2016 }, { "abstract": "Integration of decoupling capacitors into silicon carbide (SiC) metal oxide semiconductor field effect transistor mosfet) modules is an advanced solution to mitigate the effect of parasitic inductance induced by module assembly interconnects. In this paper, the switching transient behavior is reported for a 1.2 kV SiC mosfet module with embedded dc link capacitors. It shows faster switching transition and less overshoot voltage compared to a module using an identical package but without capacitors. Active power cycling and passive temperature cycling are carried out for package reliability characterization and comparisons are made with commercial Si and SiC power modules. Scanning acoustic microscopy images and thermal structure functions are presented to quantify the effects of package degradation. The results demonstrate that the SiC modules with embedded capacitors have similar reliability performance to commercial modules and that the reliability is not adversely affected by the presence of the decoupling capacitors.", "author_names": [ "Li Yang", "Ke Li", "Jingru Dai", "Martin R Corfield", "Anne Harris", "Krzysztof Paciura", "John O'Brien", "C Mark Johnson" ], "corpus_id": 52299948, "doc_id": "52299948", "n_citations": 18, "n_key_citations": 2, "score": 0, "title": "Electrical Performance and Reliability Characterization of a SiC MOSFET Power Module With Embedded Decoupling Capacitors", "venue": "IEEE Transactions on Power Electronics", "year": 2018 }, { "abstract": "This article presents an idea of achieving reliability through Industrial Internet of Things (IIoT) for industrial power systems. It proposes hybrid approach for predictive and corrective maintenance. It discusses the self corrective maintenance (SCM) paradigm as hybrid approach for industrial power systems along with condition based maintenance approach utilizing IIoT to achieve it. As it is well known that industries pay huge penalty for the down time, and suffer to meet reliability demands for years. Study witnesses its cost in millions of dollars yearly for production disruptions. It can be prevented by proactively following the aggressive maintenance schedule. However, it often becomes expensive as part or service may not be utilized for its full life and failure may occur even in middle of maintenance cycle. On the other hand, condition based maintenance (CBM) helps utilize the full life and prevents the downtime by predicting the failures ahead. This article reviews current maintenance practices followed by industry leaders and a proposal on self corrective maintenance based on condition of restorable resources. It is about learning the condition of subsystems by itself and taking corrective action when subsystem is not active. This concept helps reduce manual intervention to correct the problem as well as the maintenance cost. This research also covers the self uncorrectable issues to be handled by proactively following CBM process through IIoT. This hybrid proposal could be a significant gear shift in maintenance direction for general industry as well as power systems. It can be termed as industry's 5th revolution or Industry 5.0.", "author_names": [ "Ashok Prajapati", "Robert G Arno", "N E Dowling", "William J Moylan" ], "corpus_id": 184471826, "doc_id": "184471826", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Enhancing Reliability of Power Systems through IIoT Survey and Proposal", "venue": "2019 IEEE/IAS 55th Industrial and Commercial Power Systems Technical Conference (I&CPS)", "year": 2019 }, { "abstract": "The thermal cycling reliability of candidate copper and aluminium power substrates has been assessed for use at temperatures exceeding 300degC peak using a combination of thermal cycling, nanoindentation and finite element modelling to understand the relative stresses and evolution of the mechanical properties. The results include the relative cycling lifetimes up to 350degC, demonstrating almost an order of magnitude higher lifetime for active metal brazed Al AlN substrates over Cu Si 3 N 4 but four times more severe roughening and cracking of the Ni P plating's on the Al AlN (DBA) substrates. The nonlinear finite element modelling illustrated that the yield strength of the metal and the thickness of the ceramic are the main stress controlling factors, but comparisons with the cycling lifetime results demonstrated that the fracture toughness (resistance) of the ceramic is the over riding controlling factor for the overall passive thermal cycling lifetimes. In order to achieve the highest substrate lifetime for the highly stressed high temperature thermal cycled applications, the optimum solution appears to be annealed copper, brazed on to a thicker than normal or higher fracture toughness Si 3 N 4 ceramic.", "author_names": [ "Dean Hamilton", "Liam Mills", "James Bowen", "M R Jennings", "Philip A Mawby" ], "corpus_id": 7226414, "doc_id": "7226414", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "High temperature reliability of power module substrates", "venue": "", "year": 2015 }, { "abstract": "Prognostic health monitoring technologies, which can evaluate performance degradation, load history, and degree of fatigue, have the potential to improve the effective maintenance, reliability design methods, and availability under improper use conditions of electronics systems. We propose a method to assess the thermal fatigue life and thermal load history under asymmetric cycles of a power electronics module by using finite element method based Lagrangian neural networks. We apply this method to an insulated gate bipolar transistor power module with a temperature history monitoring function. It is shown that this method can estimate the inelastic strain cycles and thermal fatigue life distribution of the solder joints from temperature monitoring history. It is also confirmed that probabilistic load assessment of thermal cyclic load distributions can be conducted using the estimated inelastic strain cycles. It is concluded that the proposed method could be effective for assessing thermal load history and thermal fatigue life estimation in prognostic health monitoring.", "author_names": [ "H Uehara", "Tomoko Monda", "A Kano", "Tomoya Fumikura", "Kenji Hirohata" ], "corpus_id": 235616083, "doc_id": "235616083", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Prognostic Health Monitoring Method For Thermal Fatigue Failure Of Power Module Solder Joints Using The Grain Boundary Sliding Model", "venue": "2021 International Conference on Electronics Packaging (ICEP)", "year": 2021 }, { "abstract": "In renewable energy and grid applications, solder attached power modules are subject to fatigue stress cycles of low amplitudes, but the devices will be in service for decades. This article aims to understand the slow aging process by focusing on the initial defects and their growth under the stress cycles of concern. A finite element analysis (FEA) is performed to obtain the thermomechanical stress distribution around the defects, which is combined with the solder material's property to give a lifetime model. Effort is made to validate the model by power cycling plus microscale computed tomography (CT) scanning. It is found that a void in the solder layer may first transform into a crack on the material boundary, which then grows progressively more rapidly until device failure. A numerical example is shown for evaluating the lifetime of an IGBT power module in a \"soft open point\" (SOP) converter designed for an 11 kV power network.", "author_names": [ "Borong Hu", "Sylvia Konaklieva", "Nadia Kourra", "Mark A Williams", "Li Ran", "Wei Lai" ], "corpus_id": 212989877, "doc_id": "212989877", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Long Term Reliability Evaluation of Power Modules With Low Amplitude Thermomechanical Stresses and Initial Defects", "venue": "IEEE Journal of Emerging and Selected Topics in Power Electronics", "year": 2021 }, { "abstract": "The goal of this study was to understand the power cycling reliability of IGBT power modules. These power modules are made up of multi layer stacks and consist of multiple power dice in parallel. The interconnection schemes within the module include leadframes soldered to substrate, die attachment using solder and wirebonds. Thermal and power cycling fatigues material interfaces because of the CTE mismatch between dissimilar materials. In addition, wirebonds on the dice are prone to debonding because of the thermally induced stresses. Tests were designed to understand the power cycling reliability of these large transistor modules. Results from the tests are summarized in this paper.", "author_names": [ "Venkateswara Anand Sankaran", "Chingchi Chen", "C S Avant", "X Xu" ], "corpus_id": 110747542, "doc_id": "110747542", "n_citations": 68, "n_key_citations": 2, "score": 0, "title": "Power cycling reliability of IGBT power modules", "venue": "IAS '97. Conference Record of the 1997 IEEE Industry Applications Conference Thirty Second IAS Annual Meeting", "year": 1997 }, { "abstract": "This paper characterizes thermal and reliability performance of a SiC MOSFET power module with embedded decoupling capacitors and without anti parallel diodes. Active and passive temperature cycling, supported by transient thermal impedance characterisation and scanning acoustic microscopy, are used to evaluate key degradation mechanisms. The forward voltage drop of the body diode is used as a thermo sensitive electrical parameter to estimate the junction temperature and the thermal structure function is analysed to elucidate the degradation in the heat flow path inside the module. Comparisons are made with commercial Si IGBT power modules.", "author_names": [ "Li Yang", "Pearl A Agyakwa", "Martin R Corfield", "Mark Johnson", "Anne Harris", "Matthew Packwood", "Krzysztof Paciura" ], "corpus_id": 139605227, "doc_id": "139605227", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Comparison of thermal and reliability performance between a SiC MOSFET module with embedded decoupling capacitors and commercial Si IGBT power modules", "venue": "", "year": 2018 }, { "abstract": "Solder attached IGBT power modules are widely use in renewable energy and smart grid applications where the thermomechanical stress cycles are relatively low in amplitude but the service duties of the devices are expected to last for decades. Although the initial defect voids and cracks in the solder layer are widely recognized as the triggers of initial aging, it is still necessary to describe and simulate the physical fatigue behavior in their local regions accurately under low amplitude stress cycling. In order to investigate the growth of the damage, in this paper a 2D symmetrical finite element analysis (FEA) model is developed to evaluate the thermo mechanical behavior of the solder layer with initial defects, and this is verified by a combination of power cycling test and micro resolution computed tomography (CT) scanning. The modeling and its experimental validation provides an understanding that the voids distributed in the solder layer may transfer into initial cracks which then grow progressively rapidly; the voids adjacent to the chip solder interface will particularly reduce the lifetime. This establishes the basis of a modeling theory for further investigation of the damage progress on solder interface.", "author_names": [ "Borong Hu", "Sylvia Konaklieva", "Li Ran", "Nadia Kourra", "Mark A Williams", "Wei Lai", "Philip A Mawby" ], "corpus_id": 54451113, "doc_id": "54451113", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Long Term Reliability of Power Modules with Low Amplitude Thermomechanical Stresses and Initial Defects", "venue": "2018 IEEE Energy Conversion Congress and Exposition (ECCE)", "year": 2018 }, { "abstract": "The success of the high temperature power electronic applications depends on the power device reliability. The increasing thermal demands, like in hybrid electric cars, require power devices operating at junction temperatures above their common level of 125 degC. The thermal cycles generated in standard modules in such conditions induce several failure mechanisms in their package and chips. This article presents ageing tests of an EconoPIM IGBT module submitted to PWM power cycling at high ambient temperature. Several electrical and thermal parameters are monitored to detect failure onsets in the module components. Static and dynamic measurements are periodically made to reveal possible module characteristic drifts, and to better understand the effects of this kind of cycling test on the module static and switching behaviors. The follow up of the dynamic parameter evolution represents the originality of this study.", "author_names": [ "M Tounsi", "Amrane Oukaour", "Boubekeur Tala-Ighil", "Hamid Gualous", "Bertrand Boudart", "Djamil Aissani" ], "corpus_id": 10575520, "doc_id": "10575520", "n_citations": 31, "n_key_citations": 1, "score": 0, "title": "Characterization of high voltage IGBT module degradations under PWM power cycling test at high ambient temperature", "venue": "Microelectron. Reliab.", "year": 2010 } ]
Polymers in sensor applications
[ { "abstract": "Abstract Because their chemical and physical properties may be tailored over a wide range of characteristics, the use of polymers is finding a permanent place in sophisticated electronic measuring devices such as sensors. During the last 5 years, polymers have gained tremendous recognition in the field of artificial sensor in the goal of mimicking natural sense organs. Better selectivity and rapid measurements have been achieved by replacing classical sensor materials with polymers involving nano technology and exploiting either the intrinsic or extrinsic functions of polymers. Semiconductors, semiconducting metal oxides, solid electrolytes, ionic membranes, and organic semiconductors have been the classical materials for sensor devices. The developing role of polymers as gas sensors, pH sensors, ion selective sensors, humidity sensors, biosensor devices, etc. are reviewed and discussed in this paper. Both intrinsically conducting polymers and non conducting polymers are used in sensor devices. Polymers used in sensor devices either participate in sensing mechanisms or immobilize the component responsible for sensing the analyte. Finally, current trends in sensor research and also challenges in future sensor research are discussed.", "author_names": [ "Basudam Adhikari", "Sarmishtha Majumdar" ], "corpus_id": 137131089, "doc_id": "137131089", "n_citations": 1008, "n_key_citations": 8, "score": 1, "title": "Polymers in sensor applications", "venue": "", "year": 2004 }, { "abstract": "Conducting (or conjugated) polymers (CPs) are widely used for fabricating chemical and biosensors. These materials enable fabrication of devices in short lead time and at relatively low costs owing to their unique advantages of light weight, easy processability, compatibility with biological systems, tunable electronic and optic properties, large area fabrication and potential for flexible or wearable sensors. This chapter describes the basic concepts underlying the interaction of analyte with CPs as well as the other components of sensors. The operating principles of transducers used in the sensor are discussed in detail. Sensors based on conducting polymers are classified in accordance with the changes in the properties of conducting polymers. These changes involve changes in (i) doping levels, (ii) optical properties and (iii) changes due to weak interactions. Furthermore, the sensors have been reviewed for various conducting polymers such as polyaniline, polythiophene, polypyrrole, polydaicetylene for analysis of wide variety of analysts including toxic gases, radiation, pH, temperature, external stimuli; and recent advances in sensors based on conducting polymers have been discussed. Future directions and thrust in emerging field have been projected in the area of molecular engineering, material synthesis, film preparation and transducers, circuits and algorithms for developing futuristic sensors especially wearable sensors.", "author_names": [ "Vibha Saxena", "Dinesh K Aswal" ], "corpus_id": 136285378, "doc_id": "136285378", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Conducting polymers in sensor applications", "venue": "", "year": 2016 }, { "abstract": "Previous publications have shown that polymer based materials hold a great potential for the use as substrates for sensors, for example for AMR sensors. Polymers can substitute expensive substrates such as silicon or silicon oxide, and pre structured substrates can eliminate many necessary cleanroom and micro technological processes, especially photolithography. Ultimately, process optimization can yield manufacturing processes without expensive procedures (through silicon vias) guaranteeing a complete abandonment of processes such as photolithography, CMP and the like. At this point, injection molding with laser direct structuring (LDS) polymers offers distinct advantages, such as the electroless and selective deposition of metals through the directly laser activated polymers, which can be used to implement through vias. In this context, the LDS capable polyetheretherketone (PEEK) is employed herein. The thermoplastic polymer has a high glass transition temperature and features chemical resistances to many solvents. As a result, sensors can potentially cover varying areas of application, and it is additionally possible to integrate these components in micro technological processes. The presented sensor structures were produced by micro technological processes and contacted using vias realized with the LDS method. As a result, the cost effective polymer based module or rather the substrate can be integrated directly into other processes and modules, such as a system on a chip system, without the need for costly process adaptation based on high process variability. To verify this, temperature and magnetic field sensors based on the AMR effect were prepared and evaluated. Accordingly, this article aims to show that wafer level sensors can be fabricated using a process developed at the Institute of Micro Production Technology (IMPT)", "author_names": [ "Sebastian Bengsch", "Marc Christopher Wurz", "Kevin Cromwell", "Maximilian Aue" ], "corpus_id": 201743072, "doc_id": "201743072", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Structuring of Laser Activated Polymers for Sensor Applications", "venue": "2019 IEEE 69th Electronic Components and Technology Conference (ECTC)", "year": 2019 }, { "abstract": "Polymeric sensors play an increasingly important role in monitoring the environment we live in, providing relevant information for a host of applications. Among them, significant efforts have been made to fabricate polymeric sensors useful for healthcare related application fields, such as the sensitive detection of biomolecules and cellular interfacing. Within the well established field of biomedical polymeric sensors, surface modification and/or functionalization using plasma is just emerging as a technology to improve selectivity and sensitivity in the biodetection process. Treatments based on plasma irradiation of polymer surfaces, which have been traditionally applied for cleaning, etching, activating or cross linking, are currently being used to induce the formation of electrocatalytic species able to promote the oxidation of, for example, bioanalytes and/or gas molecules harmful for human health. Here, we summarize the main advances in the utilization of plasma technologies for the fabrication of polymeric sensors for advanced biomedical applications (e.g. humidity, temperature, pH, neurotransmitter, and glucose sensors)", "author_names": [ "Carlos Aleman", "Georgina Fabregat", "Elaine Armelin", "Jorge J Buendia", "Jordi Llorca" ], "corpus_id": 203933673, "doc_id": "203933673", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Plasma surface modification of polymers for sensor applications.", "venue": "Journal of materials chemistry. B", "year": 2018 }, { "abstract": "Polymeric sensors play an increasingly important role in monitoring the environment we live in, providing relevant information for a host of applications. Among them, significant efforts have been made to fabricate polymeric sensors useful for healthcare related application fields, such as the sensitive detection of biomolecules and cellular interfacing. Within the well established field of biomedical polymeric sensors, surface modification and/or functionalization using plasma is just emerging as a technology to improve selectivity and sensitivity in the biodetection process. Treatments based on plasma irradiation of polymer surfaces, which have been traditionally applied for cleaning, etching, activating or cross linking, are currently being used to induce the formation of electrocatalytic species able to promote the oxidation of, for example, bioanalytes and/or gas molecules harmful for human health. Here, we summarize the main advances in the utilization of plasma technologies for the fabrication of polymeric sensors for advanced biomedical applications (e.g. humidity, temperature, pH, neurotransmitter, and glucose sensors)", "author_names": [ "Carlos Enrique Aleman Llanso", "Georgina Fabregat Jove", "Elaine Aparecida Armelin Diggroc", "J J Morales", "Jordi Llorca Pique" ], "corpus_id": 104400874, "doc_id": "104400874", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Plasma surface modification of polymers for sensor applications", "venue": "", "year": 2018 }, { "abstract": "Surface modification of polystyrene and polyethylene naphthalate by a KrF pulse excimer UV laser under the angles of incidence of the laser beam in the range of 0 to 60Adeg with a step of 7.5Adeg was studied in this paper. The influence of the angle of incidence on the period of the resulting surface structures and the modified refractive index of the substrates was determined with all the other parameters of the laser radiation held constant. All data was acquired on the basis of surface analysis. Atomic force microscopy was used to study the morphological changes in the laser treated samples and to determine the period of the ripple like surface structures, from which the modified refractive index was subsequently calculated. Selected samples were metallized with gold with aim to determine the influence of patterned substrate on consequently formed nanolayer. These information may be useful for consequently constructed SERS system based on ripple metal system.", "author_names": [ "Vaclav Svorcik", "Oldrich Nedela", "Petr Slepicka", "Oleksiy Lyutakov", "Nikola Slepickova Kasalkova", "Zdenka Kolska" ], "corpus_id": 140085786, "doc_id": "140085786", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Construction and Properties of Ripples on Polymers for Sensor Applications", "venue": "", "year": 2018 }, { "abstract": "Thermoplastic polymers like polyolefins, polyesters, polyamide, and styrene polymers are the most representative commodity plastics thanks to their cost efficient manufacturing processes, excellent thermomechanical properties and their good environmental compatibility, including easy recycling. In the last few decades much effort has been devoted worldwide to extend the applications of such materials by conferring on them new properties through mixing and blending with different additives. In this latter context, nanocomposites have recently offered new exciting possibilities. This review discusses the successful use of nanostructured dispersed substrates in designing new stimuli responsive nanocomposites; in particular, it provides an updated description of the synthetic routes to prepare nanostructured systems having the typical properties of thermoplastic polymers (continuous matrix) but showing enhanced optical, conductive, and thermal features dependent on the dispersion topology. The controlled nanodispersion of functional labeled clays, noble metal nanoparticles and carbon nanotubes is here evidenced to play a key role in producing hybrid thermoplastic materials that have been used in the design of devices, such as NLO devices, chemiresistors, temperature and deformation sensors.", "author_names": [ "Serena Coiai", "Elisa Passaglia", "Andrea Pucci", "Giacomo Ruggeri" ], "corpus_id": 17715777, "doc_id": "17715777", "n_citations": 52, "n_key_citations": 1, "score": 0, "title": "Nanocomposites Based on Thermoplastic Polymers and Functional Nanofiller for Sensor Applications", "venue": "Materials", "year": 2015 }, { "abstract": "Molecularly Imprinted Polymers (MIP) were prepared by photochemical route. Photoinduced polymerization was used to achieve the preparation of the MIP and at the same time spatially controlled irradiation allowed shaping the material to confer it an optical function useful for interrogation. Such route significantly simplifies the integration of MIP for sensor applications. Specific photopolymerizable MIP were designed for photopolymerization at different wavelengths and advanced methods of photopatterning were used including optical near field, interference or self guiding lithography. Photopatterning appears thereby as one of the most suitable methods for patterning MIP at the micro and nano scale, directly on the transducer surface.", "author_names": [ "Yannick Fuchs", "Xu Ton", "Karsten Haupt", "Ihab Dika", "Olivier Soppera", "Andrew G Mayes" ], "corpus_id": 11199282, "doc_id": "11199282", "n_citations": 136, "n_key_citations": 0, "score": 0, "title": "Photopolymerization and photostructuring of molecularly imprinted polymers for sensor applications", "venue": "2012 IEEE Sensors", "year": 2012 }, { "abstract": "Molecularly Imprinted Polymers (MIP) were prepared by photochemical route. Photoinduced polymerization was used to achieve the preparation of the MIP and at the same time spatially controlled irradiation allowed shaping the material to confer it an optical function useful for interrogation. Such route significantly simplifies the integration of MIP for sensor applications. Specific photopolymerizable MIP were designed for photopolymerization at different wavelengths and advanced methods of photopatterning were used including optical near field, interference or self guiding lithography. Photopatterning appears thereby as one of the most suitable methods for patterning MIP at the micro and nano scale, directly on the transducer surface.", "author_names": [ "Yannick Fuchs", "Xu Ton", "Karsten Haupt", "Ihab Dika", "Olivier Soppera", "Andrew G Mayes" ], "corpus_id": 110516789, "doc_id": "110516789", "n_citations": 43, "n_key_citations": 1, "score": 0, "title": "Photopolymerization and photostructuring of molecularly imprinted polymers for sensor applications", "venue": "", "year": 2012 }, { "abstract": "Molecular imprinting is the process of template induced formation of specific recognition sites in a polymer. Synthetic receptors prepared using molecular imprinting possess a unique combination of properties such as robustness, high affinity, specificity, and low cost production, which makes them attractive alternatives to natural receptors. Improvements in polymer science and nanotechnology have contributed to enhanced performance of molecularly imprinted polymer (MIP) sensors. Encouragingly, recent years have seen an increase in high quality publications describing MIP sensors for the determination of biomolecules, drugs of abuse, and explosives, driving toward applications of this technology in medical and forensic diagnostics. This review aims to provide a focused overview of the latest achievements made in MIP based sensor technology, with emphasis on research toward real life applications.", "author_names": [ "Omar Sheej Ahmad", "Thomas S Bedwell", "Cem Esen", "Alvaro Garcia-Cruz", "Sergey A Piletsky" ], "corpus_id": 52312515, "doc_id": "52312515", "n_citations": 169, "n_key_citations": 1, "score": 0, "title": "Molecularly Imprinted Polymers in Electrochemical and Optical Sensors.", "venue": "Trends in biotechnology", "year": 2019 } ]
Improved Design of a Thermophotovoltaic Device
[ { "abstract": "In this article, we further study the parametric optimum design of a far field thermophotovoltaic device (FTPD) that consists of a radiator and a photovoltaic (PV) cell. These two basic components are made of hexagonal boron nitride (hBN) and narrowband semiconductor, respectively. The irreversible radiative and nonradiative recombination losses within the PV cell are considered. Expressions for the power density and energy conversion efficiency of the FTPD are given. The maximum power density and efficiency of the FTPD are calculated numerically for the given output voltage and the thickness of the PV cell. Making tradeoffs between the power density and the efficiency, the optimum regions of some key performance parameters are provided. The optimum operating conditions of FTPDs for three different semiconductors are presented. The effects of the radiator temperature on the optimum performances of FTPDs are discussed. The results may provide optimal design strategies for the practical manufacture of FTPDs.", "author_names": [ "Tianjun Liao", "Houcheng Zhang", "Zhi-Yong Wang" ], "corpus_id": 219456696, "doc_id": "219456696", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Improved Design of a Thermophotovoltaic Device", "venue": "IEEE Transactions on Electron Devices", "year": 2020 }, { "abstract": "An In0.68Ga0.32As thermophotovoltaic (TPV) cell on a compositionally nonmonotonically graded InAsP buffer with a band gap energy of 0.60 eV grown by metal organic chemical vapor deposition (MOCVD) has been fabricated. The performance of the TPV device was greatly improved with optimized material growth, the use of an absorption layer of suitable width, and appropriate TiO2/SiO2 antireflective coating design. Under standard AM1.5G spectra, the open circuit voltage (Voc) increases from 0.19 to 0.23 V, the short circuit current density (Jsc) increases from 43 to 56 mA/cm2, and the conversion efficiency increases from 5.31 to 8.06% By illumination at a high intensity of 50 suns, a high conversion efficiency of 12.3% with a Voc of 0.35 V is reached.", "author_names": [ "Tan Shu Ming", "Shulong Lu", "Lian Ji", "Yaqi Zhu", "Zhiming Chen" ], "corpus_id": 121821021, "doc_id": "121821021", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Optimization of In0.68Ga0.32As Thermophotovoltaic Device Grown on Compositionally Nonmonotonically Graded InAsP Buffer by Metal Organic Chemical Vapor Deposition", "venue": "", "year": 2013 }, { "abstract": "Solar thermophotovoltaic (STPV) devices provide conversion of solar energy to electrical energy through the use of an intermediate absorber/emitter module, which converts the broad solar spectrum to a tailored spectrum that is emitted towards a photovoltaic cell [1] While the use of an absorber/emitter device could potentially overcome the Shockley Queisser limit of photovoltaic conversion [2] it also increases the number of heat loss mechanisms. One of the most prohibitive aspects of STPV conversion is the thermal transfer efficiency, which is a measure of how well solar energy is delivered to the emitter. Although reported thermophotovoltaic efficiencies (thermal to electric) have exceeded 10% [3] [4] previously measured STPV conversion efficiencies are below 1% [5] [6] [7].In this work, we present the design and characterization of a nanostructured absorber for use in a planar STPV device with a high emitter to absorber area ratio. We used a process for spatially selective growth of vertically aligned multi walled carbon nanotube (MWCNT) forests on highly reflective, smooth tungsten (W) surfaces. We implemented these MWCNT/W absorbers in a TPV system with a one dimensional photonic crystal emitter, which was spectrally paired with a low bandgap PV cell. A high fidelity, system level model of the radiative transfer in the device was experimentally validated and used to optimize the absorber surface geometry. For an operating temperature of approximately 1200 K, we experimentally demonstrated a 100% increase in overall STPV efficiency using a 4 to 1 emitter to absorber area ratio (relative to a 1 to 1 area ratio) due to improved thermal transfer efficiency. By further increasing the solar concentration incident on the absorber surface, increased emitter to absorber area ratios will improve both thermal transfer and overall efficiencies for these planar devices.(c) 2013 ASME", "author_names": [ "David M Bierman", "Andrej Lenert", "Evelyn N Wang" ], "corpus_id": 113055568, "doc_id": "113055568", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Improved Thermal Transfer Efficiency for Planar Solar Thermophotovoltaic Devices", "venue": "", "year": 2013 }, { "abstract": "The present theory integrates all components of a thermophotovoltaic (TPV) device (i.e. the primary lens, the absorber, the photovoltaic (PV) cell and a photon recuperator system) Energy balances are derived for the absorber and PV cell. The TPV efficiency is maximized by using three optimization parameters, namely, absorber temperature, PV cell temperature and cell voltage. An ad hoc numerical constraint optimization procedure is developed which allows computation of an optimum absorber temperature within 5 10 K error. In case of an improved thermal design, the 'ideal' bandgap for TPV solar energy conversion is in the range 0.5 1 eV, in reasonable good agreement with present knowledge. Further improvement in thermal design quality moves the optimum bandgap toward higher values. Improving thermal design quality decreases the influence of the concentration ratio, on both optimum absorber temperature and optimum PV cell voltage. An improved thermal design allows almost all narrow bandgap materials to operate at positive voltage. The results prove existence of an optimum concentration ratio.", "author_names": [ "Viorel Badescu" ], "corpus_id": 109151382, "doc_id": "109151382", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Thermal design influence on the performance of solar thermophotovoltaic devices", "venue": "", "year": 2003 }, { "abstract": "InGaAsSb and GaSb thermophotovoltaic cells were grown lattice matched to GaSb substrates epitaxially by the Molecular Beam Epitaxy (MBE) method and fabricated non epitaxially using ion implantation. TPV cells with 1 x 1 cm dimensions were fabricated. External quantum efficiencies and device characteristics including open circuit voltage, short circuit current density, ideality factor and reverse saturation current density of the TPYs were measured and compared. For the quaternary MBE grown InGaAsSb, obtaining high Voc was challenging due to the low shunt resistance caused by growth defects in the relatively thick epitaxial design. However, this TPV demonstrated promising fundamental deuce parameters since the lowest ideality factor and reverse saturation current density were observed compared to the others. The MBE grown GaSb TPV structures had an order of magnitude thinner epitaxy and improved shunt resistance. The implanted GaSb TPYs exhibited similar performance to the MBE TPYs indicating that implant induced damage was not a limiting factor.", "author_names": [ "Nassim Rahimi", "Daniel J Henera", "Shaimaa A Abdallah", "Veronika Stelmakh", "Walker R Chan", "Ivan Celanovic", "Luke F Lester" ], "corpus_id": 20662890, "doc_id": "20662890", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Epitaxial and non epitaxial large area GaSb based thermophotovoltaic (TPV) cells", "venue": "2015 IEEE 42nd Photovoltaic Specialist Conference (PVSC)", "year": 2015 }, { "abstract": "We propose quantum cascade thermophotovoltaic structures based on intersubband transition for efficient energy conversion using GaN/AIN material system. Four designed structures combinedly absorb a broad range of blackbody spectrum from 1300 K to 2000 K, including higher energy portion of the blackbody radiation. Optimized design of relaxation path ensures efficient collection of photoexcited carriers at the device terminals, and hence, greater current density and improved device efficiency.", "author_names": [ "Sakib Hassan", "Muhammad Anisuzzaman Talukder" ], "corpus_id": 13028939, "doc_id": "13028939", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Increased radiation absorption in thermophotovoltaic quantum cascade structures", "venue": "2015 IEEE International Conference on Telecommunications and Photonics (ICTP)", "year": 2015 }, { "abstract": "Capturing waste heat as electricity using solid state microelectronics has potential benefits for a wide variety of applications. Davids et al. recently reported a 3 terminal CMOS dual tunnel diode device demonstrating power generation up to 61 mW/cm2 at 350degC. Compared to prior rectenna designs, this design experimentally demonstrates 6,800 times higher power densities, for efficiencies around 7x10 3% The enhancement may be attributed to improved rectification or to a shift to a thermophotovoltaic design; making this distinction clearly warrants further study. This work suggests that significant further improvements in solid state conversion efficiencies are still possible. Ultimately, this research direction may enable more economic recovery of waste heat in data centers, communications, radars, ground transportation, combined heat and power plants, and more.", "author_names": [ "Peter Bermel" ], "corpus_id": 219479046, "doc_id": "219479046", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Capturing Waste Heat with CMOS Microelectronics", "venue": "", "year": 2020 }, { "abstract": "The recent interest in thermophotovoltaics (TPV) for space power applications has necessitated consideration of new device designs that are optimized for operation at elevated temperatures in order to be compatible with practical space platform power systems. Photovoltaic device performance degrades as operating temperature is increased due to increasing dark current density (Jo) A cooling system is therefore required to maintain a low cell temperature with respect to the emitter ~1300 K) However, the cold side cooling capacity is directly related to the temperature, size and mass of a passive radiator. Therefore, since a high power to weight ratio is a critical factor for spacecraft power system design, the ability to realize devices capable of improved power density at elevated temperatures is critical to minimize the mass of space TPV systems. A simple model has been developed to estimate the effect of temperature on device electrical properties. Design parameters under investigation are the modific.", "author_names": [ "Fred Newman", "Susan L Murray", "Scott Endicter", "Daniel J Aiken", "G R Girard", "Michele Turner", "Paul R Sharps" ], "corpus_id": 109305507, "doc_id": "109305507", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Development of Thermophotovoltaic Devices Optimized for High Temperature Operation", "venue": "", "year": 2005 }, { "abstract": "A new testing platform for semiconductor solar devices and solar concentration applications has been developed. By separating the solar radiation into two beams using a dichroic lens, simultaneous operation of a photovoltaic (PV) and a thermophotovoltaic (TPV) cell is made possible. Photons with a wavelength shorter than 1100 nm are reflected onto a PV cell; whereas the remaining solar spectrum is refracted towards a TPV cell. This testing platform takes advantage of auto tracking and focusing capabilities using a digital mount and photoresistors. Alternative solutions to cooling problems have also been offered. Various concentration ratios, incident light intensities, acceptance angles and spot sizes can be achieved due to the versatile nature of this device. Issues with mismatching lattice constants have also been addressed through spectrum splitting. This design, when operated at its full capacity with a 3 junction PV cell and a TPV cell, allows for exciting new possibilities in high efficiency solar cell technology. These possibilities include the 3+1 hybrid multijunction cell design which could lead to higher overall efficiencies than conventional concentrators.", "author_names": [ "Emir Salih Magden", "Han-Ting Chen", "Chandler Downs", "Thomas E Vandervelde" ], "corpus_id": 3208386, "doc_id": "3208386", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "3+1 multijunction testing and operations platform for improved PV and TPV efficiencies", "venue": "2010 IEEE Conference on Innovative Technologies for an Efficient and Reliable Electricity Supply", "year": 2010 }, { "abstract": "Thermophotovoltaic and rectenna devices can be greatly improved by frequency selective emitters, which narrow the emission spectrum of a heat source to couple to the most efficient operating point of the device. We have simulated an alumina and titanium emitter using a Fabry Perot design which is intended for use with thermal energy converters operating in the near to mid infrared region.", "author_names": [ "John Chivers", "Thomas E Vandervelde" ], "corpus_id": 32362350, "doc_id": "32362350", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Broad area, selective emitters for high temperature operation", "venue": "2017 IEEE 60th International Midwest Symposium on Circuits and Systems (MWSCAS)", "year": 2017 } ]
Mach Zhender Electro Optical Modulator
[ { "abstract": "Recently, there is increasing interest in high spectral efficiency (SE) optical superchannel transmission employing an optical frequency comb generator (OFCG) driven by a single semiconductor laser. This paper introduces a new configuration for OFCG suitable for this application which consists of series connection of a dual parallel Mach Zhender modulator (DP MZM) and two electro absorption modulators (EAMs) The proposed configuration is able to generate 62 comb lines, within 1 dB flatness, separated by 25 GHz spacing. The use of the proposed comb in 64 channel WDM superchannel operating with 160Gbps dual polarization 16 QAM signal per comb line is demonstrated by simulation over around 500 km transmission. The simulation is based on a commercial package, namely Optisystem ver. 15.", "author_names": [ "Adnan Ali Abdullah", "Raad S Fyath" ], "corpus_id": 220668687, "doc_id": "220668687", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "High Spectral Efficiency Transmission Based on New Design of Optical Frequency Comb Generato", "venue": "2020 International Conference on Computer Science and Software Engineering (CSASE)", "year": 2020 }, { "abstract": "A model is created to study the role of impedance matching in indium phosphide modulators. The frequencydependent characteristic impedance and propagation constant of the electrical transmission line structure is calculated from the cross section of the phase modulator, electrode geometry, and p i n junction. The impedance and propagation constant are used in combination with a closed form approximation for the traveling wave electrode and electrical circuit to create the non iterative compact model. It yields good agreement with the experiment in a 50 Ohm measurement environment and the effect of changing source and termination impedance has been modeled. The 3dB optical modulation bandwidth is predicted to increase from 30GHz to 60GHz with optimized impedance matching and the associated suppression of electrical reflections.", "author_names": [ "A Meighan" ], "corpus_id": 220250628, "doc_id": "220250628", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Microwave model for optimizing electro optical modulation response of the Mach Zehnder modulator", "venue": "", "year": 2020 }, { "abstract": "A low voltage operation electro optic modulator is critical for applications ranging from optical communications to an analog photonic link. This paper reports a hybrid silicon nitride and lithium niobate electro optic Mach Zehnder modulator that employs 3 dB multimode interference couplers for splitting and combining light. The presented amplitude modulator with an interaction region length of 2.4 cm demonstrates a DC half wave voltage of only 0.875 V, which corresponds to a modulation efficiency per unit length of 2.11 V cm. The power extinction ratio of the fabricated device is approximately 30 dB, and the on chip optical loss is about 5.4 dB.", "author_names": [ "Abu Naim Rakib Ahmed", "Sean Nelan", "Shouyuan Shi", "Peng Yao", "Andrew J Mercante", "Dennis W Prather" ], "corpus_id": 211555859, "doc_id": "211555859", "n_citations": 16, "n_key_citations": 1, "score": 0, "title": "Subvolt electro optical modulator on thin film lithium niobate and silicon nitride hybrid platform.", "venue": "Optics letters", "year": 2020 }, { "abstract": "Optical frequency combs (OFCs) are involved in a large diversity of applications such as metrology, telecommunication or spectroscopy. Different techniques have been explored during the last years for their generation. Using an electrooptical modulator (EOM) it is possible to generate a fully tunable OFC for which the optical repetition rate is set by the frequency of the applied electrical radio frequency (RF) signal. In order to realize on chip OFC generators, silicon photonics is a well suited technology, benefiting from large scale fabrication facilities and the possibility to integrate the electronics with the EOM. However, observing OFCs with a repetition rate lower than 10 GHz can be challenging since such spacings are smaller than the typical resolution of grating based optical spectrum analyzers. To overcome this issue, two alternative solutions based on heterodyne detection techniques are used to image the OFC on the electrical RF domain. The first technique consists in applying two frequencies close to each other simultaneously on the modulator, and observing the beating between the resulting two combs. Another method consists in observing the beating between the OFC and the input laser, once the frequency of this input laser has been shifted from the center of the OFC by means of an acousto optic modulator. Based on both measurement techniques, OFCs containing more than 10 lines spaced with repetition rates from 100 MHz to 15 GHz have been observed. They are generated using a 4 mm long silicon depletionbased traveling wave Mach Zehnder modulator (MZM) operating at a wavelength of 1550 nm.", "author_names": [ "Lucas Deniel", "Erwan Weckenmann", "Diego Perez-Galacho", "Laurent Bramerie", "Charles Baudot", "Margaux Barbier", "Mathilde Gay", "Frederic Boeuf", "Laurent Vivien", "Christophe Peucheret", "Delphine Marris-Morini" ], "corpus_id": 212851025, "doc_id": "212851025", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Heterodyne detection for the measurement of electro optical frequency combs generated with a silicon Mach Zehnder modulator", "venue": "OPTO", "year": 2020 }, { "abstract": "This paper propose electric optical modulator model and establish a simulation link. Combined with the simulation link at 25 Gbps transmission rate, the extinction ratio(ER) optical modulation amplitude(OMA) and bit error rate(BER) of the modulator are studied when the arm length of the modulator is between 1mm and 3mm, and the peak to peak voltage (VPP) of the input electrical signal is 2 3v, and the input optical power varies from 5 to10mw. The result are as follow In order to obtain a larger extinction ratio, it tends to increase the length of both arms of the modulator or the VPP of the input electrical signal when other condition are the same, but the ER is insensitive to changes in input optical intensity; When the length of the modulation arm is changed from 1 to 3mm, the OMA increases first and then decreases, and the BER changes inversely. Therefore, the maximum OMA and the lowest BER can be obtained by optimizing the arm length of the modulator; the BER of the modulator decreases as the input optical intensity and the VPP increases.", "author_names": [ "Zhixiong Li", "Fengman Liu", "Yu Sun", "Huimin He", "Haiyun Xue", "Juan Wei" ], "corpus_id": 218468130, "doc_id": "218468130", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Study on Characteristics of Mach Zehnder Electro Optical Modulator", "venue": "2019 20th International Conference on Electronic Packaging Technology(ICEPT)", "year": 2019 }, { "abstract": "In this paper, we propose a reconfigurable scheme for implementation of an electro optical logic gate by utilizing a Mach Zehnder interferometer (MZI) based structure. In order to achieve high performance and small footprint for the proposed logic gate, we have used a compact, broadband, low power and high speed MZI based electro optical switch which consists of a silicon graphene slot waveguide as phase shifter in each arm of the MZI structure. Our design can perform electro optical AND, OR and XOR logic functions in three different operational modes by using three electrical control signals. The functionality of the reconfigurable electro optical logic gate is investigated with the help of eye diagram analysis for all three operational modes. Simulation results show that the proposed reconfigurable logic gate is able to work under at least 62.5 Gbit/s with high extinction ratio (ER) about 24.6 dB for transverse electric polarization mode at telecommunication wavelength of 1.55 [Formula: see text]m.", "author_names": [ "Hossein Zivarian", "Abbas Zarifkar" ], "corpus_id": 115812822, "doc_id": "115812822", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A reconfigurable scheme for realization of electro optical logic gate based on silicon graphene Mach Zhender interferometer", "venue": "International Journal of Modern Physics B", "year": 2019 }, { "abstract": "The system for stabilizing an operating point of remote integrated optical Mach Zehnder modulators with a dual output has been developed. The designed electronic circuit for precise bias control had low power consumption (less than 5 mW) and could be powered through optical fiber by signal optical radiation at a wavelength of 1550 nm with a power of 15 mW. The experimental demonstration of common mode noise rejection proved a high accuracy of the quadrature operating point setting and stabilization, resistance to the light intensity noise, and low level noise and distortion added to the transmitted signals.", "author_names": [ "Aleksei Petrov", "Aleksandr V Tronev", "Peter Agruzov", "Aleksandr Shamrai", "Vladimir Sorotsky" ], "corpus_id": 228816669, "doc_id": "228816669", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "System for Stabilizing an Operating Point of a Remote Electro Optical Modulator Powered by Optical Fiber", "venue": "", "year": 2020 }, { "abstract": "A Wide Band LiNbO3 Electro Optical Modulator was designed and Fabricated. The LiNbO3 integrated optical intensity modulators consist of Mach Zehnder interferometer optical waveguide circle and coplanar waveguide (CPW) modulation electrode structure. The effects of CPW's parameter on the transmission performance of microwave by using the finite element method. Experimental results show that the fabricated Modulator obtain insert loss of 3.5dB, the extinction ratio of 30dB, the half wave voltage of the DC electrode of 4V,the half wave voltage of the traveling wave electrode of 5.5V, the power reflection of less than 13dB, the 3dB bandwidth of 18GHz", "author_names": [ "Jianwei Zhou", "Junlei Xia", "Ruidan Liu", "Jian-li Qiao" ], "corpus_id": 181350084, "doc_id": "181350084", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design and fabrication of wide band LiNbO3 electro optical modulator", "venue": "Other Conferences", "year": 2019 }, { "abstract": "In this Letter, we reported the preliminary results of an integrating periodically capacitive loaded traveling wave electrode (CL TWE) Mach Zehnder modulator (MZM) based on InP based multiple quantum well (MQW) optical waveguides. The device configuration mainly includes an optical Mach Zehnder interferometer, a direct current electrode, two phase electrodes, and a CL TWE consisting of a U electrode and an I electrode. The modulator was fabricated on a 3 in. InP epitaxial wafer by standard photolithography, inductively coupled plasma dry etching, wet etching, electroplating, etc. Measurement results show that the MZM exhibits a 3 dB electro optic bandwidth of about 31 GHz, a Vp of 3 V, and an extinction ratio of about 20 dB.", "author_names": [ "Guang Qian", "Bin Niu", "Wu Zhao", "Qiang Kan", "Xiaowen Gu", "Fengjie Zhou", "Yuechan Kong", "Tangsheng Chen" ], "corpus_id": 191134415, "doc_id": "191134415", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "CL TWE Mach Zehnder electro optic modulator based on InP MQW optical waveguides", "venue": "", "year": 2019 }, { "abstract": "", "author_names": [ "V M Afanas'ev" ], "corpus_id": 125475604, "doc_id": "125475604", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "THE ELECTRO OPTICAL MODULATOR ACCORDING TO THE SCHEME OF THE INTERFEROMETER OF MACH ZEHNDER", "venue": "", "year": 2016 } ]
Effect of temperature on semiconductor
[ { "abstract": "A circuit modeling approach to study the effect of temperature on the modulation dynamics of DH and QW Lasers is attempted using a simple and less time consuming PSPICE circuit simulator.The circuit model is developed from the rate equations for which the temperature dependent parameters are choosen suitably.The DC sweep simulation shows increased threshold current for increase in temperature.At higher temperatures ,the pulse response reveals reduction in optical pulse amplitude and an increase in relaxation oscillations.A reduction in frequency chirp amplitude at increased temperature is also observed.", "author_names": [ "M Ganesh Madhan", "N Gunasekaran", "P R Vaya" ], "corpus_id": 94160793, "doc_id": "94160793", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Circuit modeling of the effect of temperature on semiconductor Lasers", "venue": "", "year": 1998 }, { "abstract": "We present the results of consistent theoretical analysis of various factors that may lead to influence of temperature and external magnetic field on disorder in semiconductor structures. Main attention is paid to quantum well (QW) structures in which only QWs or both QW and barriers are doped (the doping level is assumed to be close to the value corresponding to the metal insulator transition) The above factors include (i) ionization of localized states to the region of delocalized states above the mobility edge, which is presumed to exist in the impurity band; (ii) the coexistence in the upper and lower Hubbard bands (upon doping of QWs as well as barriers) in this case, in particular, the external magnetic field determines the relative contribution of the upper Hubbard band due to spin correlations at doubly filled sites; and (iii) the contribution of the exchange interaction at pairs of sites, in which the external magnetic field can affect the relation between ferromagnetic and antiferromagnetic configurations. All these factors, which affect the structure and degree of disorder, lead to specific features in the temperature dependence of resistivity and determine specific features of the magnetoresistance. Our conclusions are compared with available experimental data.", "author_names": [ "N V Agrinskaya", "Veniamin I Kozub" ], "corpus_id": 125320146, "doc_id": "125320146", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Effect of temperature and magnetic field on disorder in semiconductor structures", "venue": "", "year": 2017 }, { "abstract": "The space time dynamics of electron domains in a semiconductor superlattice is studied in a tilted magnetic field with regard to the effect of temperature. It is shown that an increase in temperature substantially changes the space time dynamics of the system. This leads to a decrease in the frequency and amplitude of oscillations of a current flowing through the semiconductor superlattice. The quenching of oscillations is observed, which is attributed to the change in the drift velocity as a function of electric field strength under the variation of temperature.", "author_names": [ "Alexander G Balanov", "M T Greenaway", "Alexey A Koronovskii", "Olga I Moskalenko", "A O Sel'skii", "T Mark Fromhold", "A E Khramov" ], "corpus_id": 53127574, "doc_id": "53127574", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "The effect of temperature on the nonlinear dynamics of charge in a semiconductor superlattice in the presence of a magnetic field", "venue": "", "year": 2012 }, { "abstract": "The effect of the temperature and angle of incidence on the photonic band gap (PBG) for semiconductor based photonic crystals has been investigated. The refractive index of semiconductor layers is taken as a function of temperature and wavelength. Three structures have been analyzed by choosing a semiconductor material for one of the two materials in a bilayer structure. The semiconductor material is taken to be ZnS, Si, and Ge with air in first, second, and third structures respectively. The shifting of band gaps with temperature is more pronounced in the third structure than in the first two structures because the change in the refractive index of Ge layers with temperature is more than the change of refractive index of both ZnS and Si layers with temperature. The propagation characteristics of the proposed structures are analyzed by transfer matrix method.", "author_names": [ "J V Malik", "Kumud Jindal", "Vinay Kumar", "Vipin Kumar", "Arun Kumar", "Kh S Singh", "Talvinder Singh" ], "corpus_id": 122700953, "doc_id": "122700953", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Effect of Temperature on Photonic Band Gaps in Semiconductor Based One Dimensional Photonic Crystal", "venue": "", "year": 2013 }, { "abstract": "Smart switch chips are widely used in electronic systems. Aiming at the electromagnetic sensitivity of smart switch chips at different temperatures, the influence of ambient temperature on their electromagnetic sensitivity is studied through theoretical analysis and experimental measurement. Combined with the structure and characteristics of smart switch chip, the interference mechanism of radio frequency signal to chip is analyzed, and the influence of ambient temperature on metal oxide semiconductor (MOS) under the action of interference signal is pointed out. Direct power injection (DPI) test is used to test the immunity of the chip. The results show that the changing ambient temperature will affect the MOS transistor's mobility and change its response under electromagnetic interference, resulting in significant drift of the switch chip's electromagnetic sensitivity with environmental temperature changes. The thermal failure of MOS tubes will also affect the test results.", "author_names": [ "Z H Gao", "P Wu", "Jianfei Wu", "Hong Li", "Hongli Zhang", "B Li", "X Cai", "J Gao" ], "corpus_id": 208880575, "doc_id": "208880575", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Research of Temperature Effect on Electromagnetic Susceptibility of Smart Switch Chip", "venue": "2019 12th International Workshop on the Electromagnetic Compatibility of Integrated Circuits (EMC Compo)", "year": 2019 }, { "abstract": "In this study, we fabricated a humidity sensor using top gate field effect transistor working in subthreshold regime with a dielectric deposited onto the pentacene semiconductor acting as encapsulation layer too. The device is characterized at room temperature with different humidity rate (RH) The results showed that the subthreshold current (Ioff) level depends on the humidity rate especially due to the concomitant change of dielectrique leakage current and semiconductor conductivity. From 10% 90% of humidity rate, we observe an increase of subthreshold current after 25% of RH, and this increase was found to be reversible by pumping down. However, the electrical parameters such as mobility and threshold voltage remain unchanged under humid environment. The results obtained in this work show for the first time, to our knowledge this kind of behavior in OFET top gate devices, pointing out the combination effects of both leakage current and conductivity increasing.", "author_names": [ "Mohsen Erouel", "Abdou Karim Diallo", "El Hadji Babacar Ly", "Mane Seck" ], "corpus_id": 208629739, "doc_id": "208629739", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Humidity Sensor Using Subthreshold Regime of Flexible Organic Field Effect Transistor: Concomitant Effect of Gate Leakage Current and Semiconductor Conductivity", "venue": "2019 IEEE International Conference on Design Test of Integrated Micro Nano Systems (DTS)", "year": 2019 }, { "abstract": "Abstract The operating behavior of a silicon surface barrier semiconductor detector of 5 mm thick depletion depth has been studied over the temperature range from 270 to 313 K by recording the spectrum of 24.8 MeV protons. The temperature of the detector was controlled and measured by a PC based temperature controller. The analysis of the recorded spectra shows that the centroid of the proton energy peak remains constant up to certain optimum temperature and falls down rapidly to the lower channels beyond the optimum temperature. The resolution of the detector was found to degrade from 0.5% to 4.9% The observed degradation is found to be related to the increase in leakage current due to rise in the detector temperature.", "author_names": [ "K Udaykumar", "Basavaraj Rachappa Kerur", "S M Hangodimath", "M T Lagare", "Suneel Kumar Srivastava", "S V S Nageshwara Rao", "A Mandal", "D K Avasthi" ], "corpus_id": 97775148, "doc_id": "97775148", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "The effect of temperature on the behavior of semiconductor silicon surface barrier detectors", "venue": "", "year": 2003 }, { "abstract": "In this work, the annealing effects of e beam deposited Ta<sub>2</sub>O<sub>5</sub> films on the pH sensitivities of EIS based sensors are presented. XPS studies confirmed that the films annealed above 700 degC showed the best stoichiometry (Ta<sub>1.96</sub>O<sub>5.04</sub> compared to the as deposited film and the films annealed till 600 degC. XRD spectra confirmed the amorphous nature of the as deposited film, which remained amorphous till 600 degC and became polycrystalline above 700 degC. The EIS device showed the maximum sensitivity of 51.4mV/pH for the film annealed at 700 degC, while the device with the as deposited film had a sensitivity of 44.3mV/pH. Further increase in annealing temperature above 700 degC resulted in reduced sensitivity (31.0mV/pH) because of increased interface states (indicated by C V hysteresis in a MOS device) and enhanced cracks formation in the films (indicated by FESEM) Therefore, the annealing temperature of 700 degC was found to be the optimum annealing temperature for the e beam deposited Ta<sub>2</sub>O<sub>5</sub> films.", "author_names": [ "Narendra Kumar", "Abhay Tiwari", "Jitendra Kumar", "Siddhartha Panda" ], "corpus_id": 36207800, "doc_id": "36207800", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Effect of post deposition annealing temperature of e beam evaporated Ta2O5 films on sensitivities of electrolyte insulator semiconductor devices", "venue": "2015 2nd International Symposium on Physics and Technology of Sensors (ISPTS)", "year": 2015 }, { "abstract": "Germanium metal insulator semiconductor (MIS) structure with HfO2/Al2O3/GeO2 gate stack have been demonstrated to exhibit good performance. In this work, the effect of formation temperature of the gate stack on the quality of the gate dielectric is investigated. It is found that the higher plasma oxidation temperature helps the GeO2 formation and less interface states. But the higher deposition temperature of the ALD high k films may degrade the interface and result in higher leakage current.", "author_names": [ "E Wei", "Bing-Yue Tsui", "Pin-Jiun Wu" ], "corpus_id": 45703879, "doc_id": "45703879", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Effect of formation temperature on quality of gate dielectric on germanium substrate", "venue": "2016 IEEE 23rd International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA)", "year": 2016 }, { "abstract": "We compare the thermoelectric (TE) performances between two types of unit cell arrangements of planar unileg TE generators of silicon nanowire (Si NW) The planar TE generators are driven by the temperature gradient along the Si NW. The TE performance highly depends on how the hot and cold sides of the unit cell is oriented with respect to the neighboring cells. If the hot sides of neighboring cells are placed next to each other, TE power is improved compared to the case where the hot and cold side of TE generator is arranged alternately. Optimal conditions of Si NW length and metal wiring structure are also discussed.", "author_names": [ "Katsuki Abe", "Kaito Oda", "Motohiro Tomita", "Takeo Matsuki", "Takashi Matsukawa", "Takanobu Watanabe" ], "corpus_id": 226266181, "doc_id": "226266181", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "4 4 Effect of Unit cell Arrangement on Performance of Multi stage planar Cavity free Unileg Thermoelectric Generator Using Silicon Nanowires", "venue": "2020 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD)", "year": 2020 } ]
The reliability of planar GaAs Schottky diodes
[ { "abstract": "Planar GaAs Schottky barrier mixer diodes are now being used in a variety of applications at millimeter and submillimeter wavelengths. Since these devices are being considered for space applications, device reliability is a critical issue. This paper presents first results from accelerated life testing of planar mixer diodes. THEORY OF ACCELERATED LIFE TESTING Accelerated life testing is the application of some stress to the device under test in order to shorten its time to failure. In this study on planar gallium arsenide Schottky diodes, the applied stress has been chosen to be elevated temperature. Various studies on semiconductor devices have found that the reaction rate of the physical or chemical process that causes failure is related to temperature as given by the following Arrhenius equation [1]", "author_names": [ "Jodi L Bowers" ], "corpus_id": 173185721, "doc_id": "173185721", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "The reliability of planar GaAs Schottky diodes", "venue": "International Conference on Infrared and Millimeter Waves", "year": 1992 }, { "abstract": "A previously reported technology that allows for the fabrication of semiconductor devices based on quartz (or other dissimilar substrates) has resulted in state of the art mixer performance at frequencies up to 640 GHz. The present work will discuss the procedure that has been used to quantify the reliability of such devices for space borne missions. A number of accelerated lifetime tests have been conducted. It is concluded that these devices exhibit lifetimes that are consistent with other GaAs devices for space applications. Our accelerated lifetime data, analyzed with the Arrhenius lognormal model, predict a room temperature MTTF on the order of 10 hours, a value that is comparable to conventional high frequency planar Schottky diodes. This result demonstrates that the use of an appropriate epoxy to obtain GaAs devices on quartz substrates does not reduce the lifetime of the devices.", "author_names": [ "Robert Lin", "A Pease", "Robert J Dengler", "D A Humphrey", "T H Lee", "Sammy Kayali" ], "corpus_id": 56431893, "doc_id": "56431893", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "QUARTZ BASED GaAs SCHOTTKY DIODES LIFETIME AND FAILURE ANALYSIS", "venue": "", "year": 2009 }, { "abstract": "We have developed a reliable, high performance, batch processed, GaAs tantalum Schottky diode (with a gold overlayer) and native oxide passivated junction1in a quasi planar configuration, Varactors and mixers have been fabricated with near ideal characteristics and state of the art performance. Typically, they exhibit, at 0 V, a junction capacitance near 0.1 pF and a cutoff frequency in excess of 700 GHz when measured at 55 GHz. In a paramp application pumped at 101 GHz, and a signal frequency of 35 GHz, we have obtained a noise figure of 3.5 dB, a gain of 17 dB, and a bandwidth of 600 MHz. When used as frequency doublers (50 100 GHz) and triplers (35 105 GHz) we have realized better than 25 percent efficiency. As mixers, atXband, we achieved a single sideband noise figure of 6 dB and the diodes are typically able to sustain short pulse energy (1.5 x 10 9s) of up to 4.5 ergs with no performance degradation. Reliability tests results to date indicate a MTBF of better than 108h at 100degC and greater than 105h at 200degC. In a commercial application of paramps (3.7 4.2 GHz) these diodes have successfully completed 2.5 million operational varactor hours with no performance degradation.", "author_names": [ "Joseph A Calviello", "J L Wallace" ], "corpus_id": 27188210, "doc_id": "27188210", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Performance and reliability of an improved high temperature GaAs Schottky junction and native oxide passivation", "venue": "IEEE Transactions on Electron Devices", "year": 1977 }, { "abstract": "Planar GaAs Schottky diodes will be utilized for all of the LO chains on the HIPI instrument for the Herschel Space Observatory. A better understanding of device degradation mechanisms is desirable in order to specify environmental and operational conditions that do not reduce device life times. Failures and degradation associated with ESD (Electrostatic Discharge) high temperatures, DC currents and RF induced current and heating have been investigated. The goal is to establish a procedure to obtain the safe operating range for a given frequency multiplier.", "author_names": [ "Frank Maiwald", "Erich Schlecht", "Robert Lin", "John S Ward", "John C Pearson", "Peter H Siegel", "Imran Mehdi" ], "corpus_id": 54219658, "doc_id": "54219658", "n_citations": 6, "n_key_citations": 1, "score": 0, "title": "Reliability of Cascaded THz Frequency Chains with Planar GaAs Circuits", "venue": "", "year": 2004 }, { "abstract": "Impact ionization in GaAs based planar Gunn diodes is studied through electroluminescence (EL) analysis with the aim of reducing its magnitude by means of contact design and shaping, and thus enhance device performance and reliability. Designs in which the diode ohmic anode has an overhanging Schottky extension (composite anode contact) are shown to result in a significantly reduced amount of impact ionization, as compared with a simple ohmic contact design. The EL results are consistent with Monte Carlo simulations, which show a reduced impact ionization in composite anode contact devices due to a reduced electron density beneath the anode Schottky extension that, on the one hand, weakens the Gunn domain electric field and softens its variations near the anode edge, and, on the other hand, reduces the number of electrons capable of generating holes by impact ionization. A comparison between standard and composite anode contact approaches in terms of radio frequency operation of the devices is made showing oscillations up to 109 GHz with an output power of 5 dBm in devices featuring the composite anode contact and no oscillations from all ohmic contact devices. The findings reported in this paper may be useful not only for the design and the fabrication of planar Gunn diodes but also for other devices such as high electron mobility transistors where impact ionization can result in reliability limitations.", "author_names": [ "Miguel Montes", "Geoffrey Dunn", "Andreas Stephen", "Ata Khalid", "Chen Li", "David R S Cumming", "Chris Oxley", "Richard Hopper", "Martin Kuball" ], "corpus_id": 26724132, "doc_id": "26724132", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Reduction of Impact Ionization in GaAs Based Planar Gunn Diodes by Anode Contact Design", "venue": "IEEE Transactions on Electron Devices", "year": 2012 }, { "abstract": "A GaAs planar airbridged Schottky (PAS) diode process has been developed for insertion in high performance circuits at millimeter wave frequencies and beyond. The PAS diodes have shown a very low resistance, accompanied by low capacitance values resulting from the small anode geometry and optimization of the diode resistance. The process is developed on 4\" GaAs wafers and show diode yield of >95% per wafer. The reliability of the junction is also discussed with an elevated 200 degrees thermal cycle test over a period of 24 hours showing no change in diode parameters such as ideality factor and breakdown voltage.", "author_names": [ "Hooman Kazemi", "Lan Tran", "D S Deakin", "Jonathan Hacker", "Chanh Nguyen" ], "corpus_id": 107430072, "doc_id": "107430072", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Highly Reliable GaAs Planar Airbridged Schottky Diodes for Flight Qualified Millimeter wave Circuits", "venue": "", "year": 2006 }, { "abstract": "Impact ionisation in GaAs based planar Gunn diodes is studied through electroluminescence analysis with the aim of reducing its magnitude by means of contact design and shaping and thus enhance device performance and reliability. Designs in which the diode ohmic anode has an overhanging Schottky extension (composite anode contact) are shown to result in a significantly reduced amount of impact ionisation compared to a simple ohmic contact design. The electroluminescence results are consistent with Monte Carlo simulations which show a reduced impact ionisation in composite anode contact devices due to a reduced electron density beneath the anode Schottky extension that, on the one hand, weakens the Gunn domain electric field and softens its variations near the anode edge, and, on the other hand, reduces the number of electrons capable of generating holes by impact ionisation. A comparison between standard and composite anode contact approaches in terms of RF operation of the devices is made showing oscillations up to 109 GHz with an output power of 5 dBm in devices featuring the composite anode contact and no oscillations from all ohmic contact devices. The findings reported in this work may be useful not only for the design and fabrication of planar Gunn diodes, but also for other devices such as HEMTs where impact ionisation can result in reliability limitations.", "author_names": [ "Miguel Montes", "Geoffrey Dunn", "Andreas Stephen", "Ata Khalid", "Changping Li", "David R S Cumming", "Chris Oxley", "", "Harriet A Hopper", "Martin Kuball" ], "corpus_id": 56043291, "doc_id": "56043291", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Kuball, M. (2012) Reduction of Impact Ionization in GaAs Based Planar Gunn Diodes by Anode Contact Design. IEEE Transactions on Electron Devices, 59(3) 654 660. DOI: 10.1109/TED.2011.2177094", "venue": "", "year": 2011 }, { "abstract": "Fix tuned, broadband local oscillator (LO) sources to 1900 GHz have been developed for the HIFI instrument on the Herschel Space Observatory. Each LO chain consists of cascaded multipliers (doublers or triplers) being pumped with high power >100 mW) power amplifier modules in the 70 to 110 GHz frequency range. For long term mission reliability it is important to quantify the safe operating conditions for these multi pliers, especially when pumped with high input power. This paper will describe on going investigations into the ef fects of excessive reverse currents in Schottky diodes along with presenting a methodology for determining safe bias conditions for a given multiplier.", "author_names": [ "Frank Maiwald", "Erich Schlecht", "John S Ward", "Robert Lin", "Rosa Leon", "John C Pearson", "Imran Mehdi" ], "corpus_id": 55028046, "doc_id": "55028046", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Design and operational considerations for robust planar GaAs varactors: A reliability study", "venue": "", "year": 2003 }, { "abstract": "Significant improvements in the reliability as well as yield and reproducibility of GaAs planar doped barrier (PDB) microwave detector diodes have been achieved by substituting carbon doped acceptor regions in place of conventional beryllium acceptor dopant. The superior characteristics of the C doped PDB diodes are thought to be related to the hyperabrupt and stable carbon acceptor doping spikes (10 60 A) obtained in the n/sup i p/sup i n/sup doping profile grown by molecular beam epitaxy (MBE) Mesa geometry PDB diodes (10 20 micron diameter) in micropill packages were RF tested at 10 and 35 GHz. Excellent tangential sensitivity up to 58 dBm was measured with a detector video impedance of 2 50 kohms depending upon barrier height. The electrostatic discharge (ESD) failure threshold voltages were found to be much higher for the PDB diodes (3500 V) in comparison to Schottky detector diodes (300 V)<ETX>", "author_names": [ "Roger J Malik", "Yoginder Anand", "Miroslav Micovic", "Michael Geva", "R W Ryan" ], "corpus_id": 135694196, "doc_id": "135694196", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Performance and reliability characteristics of GaAs planar doped barrier detector diodes using carbon doped acceptor spikes grown by molecular beam epitaxy", "venue": "Proceedings of IEEE/Cornell Conference on Advanced Concepts in High Speed Semiconductor Devices and Circuits", "year": 1993 }, { "abstract": "Planar doped barrier (PDB) diodes with extremely low barrier heights and highly asymmetric I V characteristics have been developed using MBE (molecular beam epitaxy) grown GaAs material. The authors report on the RF performance of these devices and discuss the significant advantages offered by PDB devices over conventional Schottky diodes for mixer and detector applications at both microwave and millimeter wave frequencies. These advantages include reduced mixer driver levels, reduced low frequency noise generation, improved detector tangential sensitivity and general reliability improvements as a result of the burnout performance.<ETX>", "author_names": [ "I Dale", "Angus Condie", "S Neylon", "Michael J Kearney" ], "corpus_id": 111345396, "doc_id": "111345396", "n_citations": 15, "n_key_citations": 1, "score": 0, "title": "Planar doped barrier mixer and detector diodes as alternatives to Schottky diodes for both microwave and millimetre wave applications", "venue": "IEEE MTT S International Microwave Symposium Digest", "year": 1989 } ]
organic solar cell advantage
[ { "abstract": "The need to develop inexpensive renewable energy sources stimulates scientific research for efficient, low cost photovoltaic devices.1 The organic, polymer based photovoltaic elements have introduced at least the potential of obtaining cheap and easy methods to produce energy from light.2 The possibility of chemically manipulating the material properties of polymers (plastics) combined with a variety of easy and cheap processing techniques has made polymer based materials present in almost every aspect of modern society.3 Organic semiconductors have several advantages: (a) lowcost synthesis, and (b) easy manufacture of thin film devices by vacuum evaporation/sublimation or solution cast or printing technologies. Furthermore, organic semiconductor thin films may show high absorption coefficients4 exceeding 105 cm 1, which makes them good chromophores for optoelectronic applications. The electronic band gap of organic semiconductors can be engineered by chemical synthesis for simple color changing of light emitting diodes (LEDs).5 Charge carrier mobilities as high as 10 cm2/V,s6 made them competitive with amorphous silicon.7 This review is organized as follows. In the first part, we will give a general introduction to the materials, production techniques, working principles, critical parameters, and stability of the organic solar cells. In the second part, we will focus on conjugated polymer/fullerene bulk heterojunction solar cells, mainly on polyphenylenevinylene (PPV) derivatives/(1 (3 methoxycarbonyl) propyl 1 phenyl[6,6]C61) (PCBM) fullerene derivatives and poly(3 hexylthiophene) (P3HT)/PCBM systems. In the third part, we will discuss the alternative approaches such as polymer/polymer solar cells and organic/inorganic hybrid solar cells. In the fourth part, we will suggest possible routes for further improvements and finish with some conclusions. The different papers mentioned in the text have been chosen for didactical purposes and cannot reflect the chronology of the research field nor have a claim of completeness. The further interested reader is referred to the vast amount of quality papers published in this field during the past decade.", "author_names": [ "Serap Gunes", "Helmut Neugebauer", "Niyazi Serdar Sariciftci" ], "corpus_id": 81670, "doc_id": "81670", "n_citations": 5373, "n_key_citations": 45, "score": 1, "title": "Conjugated polymer based organic solar cells.", "venue": "Chemical reviews", "year": 2007 }, { "abstract": "Photons In, Electrons Out: Basic Principles of PV Electrons and Holes in Semiconductors Generation and Recombination Junctions Analysis of the p n Junction Monocrystalline Solar Cells Thin Film Solar Cells Managing Light Over the Limit: Strategies for Higher Efficiency.", "author_names": [ "J Roy Nelson" ], "corpus_id": 117097776, "doc_id": "117097776", "n_citations": 2054, "n_key_citations": 184, "score": 0, "title": "The physics of solar cells", "venue": "", "year": 2003 }, { "abstract": "Excitonic solar cells1 including organic, hybrid organic inorganic and dye sensitized cells (DSCs) are promising devices for inexpensive, large scale solar energy conversion. The DSC is currently the most efficient2 and stable3 excitonic photocell. Central to this device is a thick nanoparticle film that provides a large surface area for the adsorption of light harvesting molecules. However, nanoparticle DSCs rely on trap limited diffusion for electron transport, a slow mechanism that can limit device efficiency, especially at longer wavelengths. Here we introduce a version of the dye sensitized cell in which the traditional nanoparticle film is replaced by a dense array of oriented, crystalline ZnO nanowires. The nanowire anode is synthesized by mild aqueous chemistry and features a surface area up to one fifth as large as a nanoparticle cell. The direct electrical pathways provided by the nanowires ensure the rapid collection of carriers generated throughout the device, and a full Sun efficiency of 1.5% is demonstrated, limited primarily by the surface area of the nanowire array.", "author_names": [ "Matt Law", "Lori E Greene", "Justin C Johnson", "Richard J Saykally", "Peidong Yang" ], "corpus_id": 37360993, "doc_id": "37360993", "n_citations": 4793, "n_key_citations": 36, "score": 0, "title": "Nanowire dye sensitized solar cells", "venue": "Nature materials", "year": 2005 }, { "abstract": "Organic solar cell research has developed during the past 30 years, but especially in the last decade it has attracted scientific and economic interest triggered by a rapid increase in power conversion efficiencies. This was achieved by the introduction of new materials, improved materials engineering, and more sophisticated device structures. Today, solar power conversion efficiencies in excess of 3% have been accomplished with several device concepts. Though efficiencies of these thin film organicdevices have not yet reached those of their inorganic counterparts (e 10 20% the perspective of cheap production (employing, e.g. roll to roll processes) drives the development of organic photovoltaic devices further in a dynamic way. The two competitive production techniques used today are either wet solution processing or dry thermal evaporation of the organic constituents. The field of organic solar cells profited well from the development of light emitting diodes based on similar technologies, which have entered the market recently. We review here the current status of the field of organic solar cells and discuss different production technologies as well as study the important parameters to improve their performance.", "author_names": [ "Harald Hoppe", "Niyazi Serdar Sariciftci" ], "corpus_id": 22455511, "doc_id": "22455511", "n_citations": 2188, "n_key_citations": 49, "score": 0, "title": "Organic solar cells: An overview", "venue": "", "year": 2004 }, { "abstract": "nature photonics VOL 6 MARCH 2012 www.nature.com/naturephotonics 153 Harnessing solar energy is one of the most promising ways to tackle today's energy issues. Although the present dominant photovoltaic (PV) technology is based on inorganic materials, high material and manufacturing costs limit its wide acceptance1. Intensive research has been conducted towards the development of low cost PV technologies, of which organic photovoltaic (OPV) devices are one of the promising. OPV devices are based on organic semiconductors carbon based materials whose backbones are comprised mainly of alternating C C and C=C bonds. Electron delocalization along the conjugated backbone is responsible for the semiconducting properties of OPV devices2. One of the major differences between organic semiconductors and inorganic semiconductors is the presence of tightly bonded excitons (electron hole pairs) resulting from their low dielectric constant (er 2 4) The binding energy of the Frenkel exciton is in the range of 0.3 1 eV (refs 2,3) Such a large binding energy prevents exciton dissociation by an electrical field (a non radiative decay channel) and can achieve a high electroluminescent efficiency in organic light emitting devices. The weak intermolecular van de Waals interaction enables the realization of low cost, large area deposition technologies such as roll toroll printing3. In recent years, organic electronic devices such as organic light emitting diodes (OLEDs) organic thin film transistors, OPVs and organic memory devices have attracted considerable attention, owing to their potential low cost and high performance characteristics. OLED displays have gained a considerable share in the portable electronics market, for use in devices such as smart phones. However, research into OPV cells continues to lag behind, despite the first patent4 and the first paper5 by Tang appearing ahead of those of OLEDs, probably owing to the fact that developing alternative energy sources has been viewed, until recently, as being relatively unimportant. OPVs are divided into two different categories according to whether their constituent molecules are either small or large (polymers) These two classes of materials are rather different in terms of their synthesis, purification and device fabrication processes. Polymer solar cells (PSCs) are processed from solution in organic solvents, whereas small molecule solar cells are processed mainly using thermal evaporation deposition in a high vacuum environment. Using the solution process to fabricate small molecule solar cells has recently been gaining momentum6, although the film quality and crystallization is expected to be an issue. PSCs are attractive owing to a number of advantageous features7, including their thin film architecture and low material consumption resulting from a high absorption coefficient, their use of organic polymer solar cells", "author_names": [ "Gang Li", "Rui Zhu", "Yang Yang" ], "corpus_id": 15721229, "doc_id": "15721229", "n_citations": 1018, "n_key_citations": 12, "score": 0, "title": "Polymer solar cells", "venue": "", "year": 2012 }, { "abstract": "Chemically tuned inorganic organic hybrid materials, based on CH3NH3( MA)Pb(I(1 x)Br(x))3 perovskites, have been studied using UV vis absorption and X ray diffraction patterns and applied to nanostructured solar cells. The band gap engineering brought about by the chemical management of MAPb(I(1 x)Br(x))3 perovskites can be controllably tuned to cover almost the entire visible spectrum, enabling the realization of colorful solar cells. We demonstrate highly efficient solar cells exhibiting 12.3% in a power conversion efficiency of under standard AM 1.5, for the most efficient device, as a result of tunable composition for the light harvester in conjunction with a mesoporous TiO2 film and a hole conducting polymer. We believe that the works highlighted in this paper represent one step toward the realization of low cost, high efficiency, and long term stability with colorful solar cells.", "author_names": [ "Jun Hong Noh", "Sang Hyuk Im", "Jin Hyuck Heo", "Tarak Nath Mandal", "Sang Il Seok" ], "corpus_id": 5115990, "doc_id": "5115990", "n_citations": 3243, "n_key_citations": 30, "score": 0, "title": "Chemical management for colorful, efficient, and stable inorganic organic hybrid nanostructured solar cells.", "venue": "Nano letters", "year": 2013 }, { "abstract": "We demonstrate that semiconductor nanorods can be used to fabricate readily processed and efficient hybrid solar cells together with polymers. By controlling nanorod length, we can change the distance on which electrons are transported directly through the thin film device. Tuning the band gap by altering the nanorod radius enabled us to optimize the overlap between the absorption spectrum of the cell and the solar emission spectrum. A photovoltaic device consisting of 7 nanometer by 60 nanometer CdSe nanorods and the conjugated polymer poly 3(hexylthiophene) was assembled from solution with an external quantum efficiency of over 54% and a monochromatic power conversion efficiency of 6.9% under 0.1 milliwatt per square centimeter illumination at 515 nanometers. Under Air Mass (A.M. 1.5 Global solar conditions, we obtained a power conversion efficiency of 1.7%", "author_names": [ "Wendy U Huynh", "Janke J Dittmer", "A Paul Alivisatos" ], "corpus_id": 28606022, "doc_id": "28606022", "n_citations": 4185, "n_key_citations": 22, "score": 0, "title": "Hybrid Nanorod Polymer Solar Cells", "venue": "Science", "year": 2002 }, { "abstract": "Organolead trihalide perovskite materials have been successfully used as light absorbers in efficient photovoltaic cells. Two different cell structures, based on mesoscopic metal oxides and planar heterojunctions have already demonstrated very impressive advances in performance. Here, we report a bilayer architecture comprising the key features of mesoscopic and planar structures obtained by a fully solution based process. We used CH3NH3 Pb(I(1 x)Br(x))3 (x 0.1 0.15) as the absorbing layer and poly(triarylamine) as a hole transporting material. The use of a mixed solvent of g butyrolactone and dimethylsulphoxide (DMSO) followed by toluene drop casting leads to extremely uniform and dense perovskite layers via a CH3NH3I PbI2 DMSO intermediate phase, and enables the fabrication of remarkably improved solar cells with a certified power conversion efficiency of 16.2% and no hysteresis. These results provide important progress towards the understanding of the role of solution processing in the realization of low cost and highly efficient perovskite solar cells.", "author_names": [ "Nam Joong Jeon", "Jun Hong Noh", "Young Chan Kim", "Woon Seok Yang", "Seungchan Ryu", "Sang Il Seok" ], "corpus_id": 205410102, "doc_id": "205410102", "n_citations": 4559, "n_key_citations": 38, "score": 0, "title": "Solvent engineering for high performance inorganic organic hybrid perovskite solar cells.", "venue": "Nature materials", "year": 2014 }, { "abstract": "A thin film, two layer organic photovoltaiccell has been fabricated from copper phthalocyanine and a perylene tetracarboxylic derivative. A power conversion efficiency of about 1% has been achieved under simulated AM2 illumination. A novel feature of the device is that the charge generation efficiency is relatively independent of the bias voltage, resulting in cells with fill factor values as high as 0.65. The interface between the two organic materials, rather than the electrode/organic contacts, is crucial in determining the photovoltaicproperties of the cell.", "author_names": [ "Ching Wan Tang" ], "corpus_id": 121105241, "doc_id": "121105241", "n_citations": 4152, "n_key_citations": 58, "score": 0, "title": "Two layer organic photovoltaic cell", "venue": "", "year": 1986 }, { "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 } ]
Wilson Current Mirrors analysis
[ { "abstract": "The MOSFET (Metal Oxide Field Effect Transistor) is one of the most widely used semiconductor devices in analog and digital circuits for amplification and switching. It is a highly popular power de vice used in power electronics. The important advantages of MOSFET include higher efficiency at lower operating voltages; there is no gate current resulting in high input impedance enhancing its switching speeds. A differential amplifier is a direct coupled amplifier that amplifies the difference between the two input signals arriving at its input and suppresses the common voltage between the two inputs. The important parameter that determines the performance of a differential amplifier is its CMRR which determines the capability of it to amplify the differential mode signal and cancel the common mode signal i.e. noise. To improve the CMRR, the resistor RE is replaced by an active load i.e. the current mirror circuit. In this paper, the performance of MOSFET differential amplifier (BiMOS Differential pair) is evaluated using Active MOSFET Load, Wilson Current Mirror and Widlar Current Mirror Circuits. The results of the implementation show that the highest CMRR (31.48 dB) is obtained by using the Diode Connected Topology.", "author_names": [ "Gouri Shashank Deo", "Jyas Aloke Totlani", "Kowshik Eshwar Mamidi", "Chaitanya Vijaykumar Mahamuni" ], "corpus_id": 219990567, "doc_id": "219990567", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Performance Analysis of BiMOS Differential Pair with Active Load, Wilson and Widlar Current Mirrors, and Diode Connected Topology", "venue": "2020 4th International Conference on Intelligent Computing and Control Systems (ICICCS)", "year": 2020 }, { "abstract": "Digital Object Identifier 10.29292/jics.v15i2.159 Abstract In this paper the performance of different architectures of current mirrors implemented with single SOI transistors and self cascode transistors, both symmetric and asymmetric is evaluated. A comparison of current mirrors figures of merit, looking for the advantages of the asymmetric composite structure in relation to a single SOI MOSFETs and the symmetric self cascode transistor is performed. This analysis has been carried out through analytical simulations, using common source, Cascode and Wilson current mirrors architectures. It is shown that asymmetric configuration can provide larger output resistance even in the common source current mirror than other architectures with conventional single transistors.", "author_names": [ "Paulo Rodrigues da Silva", "Michelly de Souza" ], "corpus_id": 225352150, "doc_id": "225352150", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Analysis of Current Mirrors with Asymmetric Self Cascode Association of SOI MOSFETs through SPICE Simulations", "venue": "", "year": 2020 }, { "abstract": "This paper presents two optimized designs for the Wilson and improved Wilson MOS current mirrors. The paper includes a detailed analysis of the high frequency behaviour of the Wilson and improved Wilson MOS current mirrors, which shows a current transfer function with two poles and one zero. The two optimized designs lead to a response which is better than that of the simple current mirror.", "author_names": [ "Gaetano Palumbo" ], "corpus_id": 108949309, "doc_id": "108949309", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Frequency behaviour of the Wilson and improved Wilson MOS current mirrors: analysis and design strategies", "venue": "", "year": 1996 }, { "abstract": "P. Devendra Kumar1, D.Vijay Kumar2 1(M.Tech in VLSI &EMBEDED SYSTEM DESIGN, Student) 2Assistant Professor, Electronics and Communication Engineering Department Velagapudi Ramakrishna Siddhartha Engineering College, Jawaharlal Nehru Technological University Kakinada, Kanuru, Vijayawada, Andhra Pradesh Abstract: Now a days Low voltage along with low power topologies of analog and mixed signal designs have gained enormous importance due to increased demand of portable devices. The bulk driven technology is emerging as an important design technique to achieve intensifies performance in low voltage analog circuits. Low voltage self biased high swing cascode current mirror employing bulk driven nmos transistor is proposed and proposed circuit has to be simulated in cadence tool, and different current mirrors like wilson current mirror and triple cascode current mirror are implemented under bulk driven technology and simulated in cadence tool, and the results are compared with the gate driven technology", "author_names": [ "Patel Devendra Kumar" ], "corpus_id": 115645240, "doc_id": "115645240", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Analysis of Low Voltage Bulk Driven High Swing Cascode Current Mirrors for Low Voltage Applications", "venue": "", "year": 2017 }, { "abstract": "In this work a comparison between the performance of current mirrors implemented with uniformly doped and graded channel (GC) transistors operating down to low temperature (150 K) is presented. This analysis has been carried out through experimental measurements of Common source, Cascode and Wilson current mirrors architectures. The advantages of the use of graded channel transistors for implementation of current mirrors in comparison to standard ones is discussed, focusing on the increase of output swing and output resistance. In all architectures some performance degradation has been observed with the temperature reduction, although current mirrors with GC transistors still present better performance than those implemented with standard SOI transistors. Two dimensional numerical simulations were performed in order to further investigate the behavior of graded channel current mirrors, looking at the bias condition of each transistor in the current mirror architectures. The obtained results indicate that good performance, compared to that of GC current mirrors, may be obtained by combining both standard and graded channel transistors, rather than using the same channel engineering for all devices in the circuit.", "author_names": [ "Michelly de Souza", "Bruna Cardoso Paz", "Denis Flandre", "Marcelo Antonio Pavanello" ], "corpus_id": 23407359, "doc_id": "23407359", "n_citations": 6, "n_key_citations": 1, "score": 0, "title": "Asymmetric channel doping profile and temperature reduction influence on the performance of current mirrors implemented with FD SOI nMOSFETs", "venue": "Microelectron. Reliab.", "year": 2013 }, { "abstract": "This paper presents an optimized design for the Wilson and improved Wilson MOS current mirrors. The paper includes a detailed analysis of the high frequency behaviour of the Wilson and improved Wilson MOS current mirrors, which shows a current transfer function with two poles and one zero. The optimized designs leads to a response which is better than that of the simple current mirror. The proposed design is verified with Spice simulation of the current mirror in a CMOS 2 /spl mu/m technology.<ETX>", "author_names": [ "Gaetano Palumbo" ], "corpus_id": 40480940, "doc_id": "40480940", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Design of the Wilson and improved Wilson MOS current mirrors reach the best settling time", "venue": "Proceedings of IEEE International Symposium on Circuits and Systems ISCAS '94", "year": 1994 }, { "abstract": "This paper presents a comprehensive study of a negative feedback mechanism in the bipolar Wilson current mirror, which is one of the most popular current mirrors used in electronic circuit designs. Although the operation of the Wilson current mirror has been covered in most microelectronic circuit design textbooks, its unusual negative feedback mechanism is still largely obscure. As a result, attempts to calculate the output resistance of the Wilson current mirror using classical negative feedback analysis have usually given the answer that is inconsistent with the correct answers obtained from direct analysis. We believe that this is probably the main reason why the negative feedback analysis of the Wilson current mirror is mostly ignored in the literature. In this paper, we aim to disclose the hidden subtleties of the Wilson current mirror by shedding a new light on its dual loop negative feedback operation. It is shown in the paper that by doing so, we will be able to apply the negative feedback theory to the Wilson current mirror and correctly calculate its current gain and port resistances.", "author_names": [ "Jirayuth Mahattanakul", "Sitthichai Pookaiyaudom", "Christofer Toumazou" ], "corpus_id": 206959050, "doc_id": "206959050", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Understanding Wilson current mirror via the negative feedback approach", "venue": "ISCAS 2001. The 2001 IEEE International Symposium on Circuits and Systems (Cat. No.01CH37196)", "year": 2001 }, { "abstract": "The full wave wide band precision rectifier with modified second type current conveyor (MCCII) realized with the operational amplifier and three current mirrors (CM) is presented in this paper. The model of operational amplifier is adapted in such a way that it is possible to use supply current sensing in supply rails of operational amplifier with SPICE program. Wilson's realization for current mirrors is used for precise current reproduction in a wide range of the amplitude values as well as frequencies.", "author_names": [ "Slobodan Dukic" ], "corpus_id": 59494587, "doc_id": "59494587", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "The analysis of full wave wide band precision rectifier with modified second type current conveyor", "venue": "", "year": 2007 }, { "abstract": "In this paper, current mirror based Current Amplifiers (CAs) with differential structure are simulated and compared by PSPICE program using HP 0.8um CMOS process parameters. The proposed CA designs are based on four well known current mirror structures such as wilson, improved wilson, cascode, and modified cascode current mirrors. The comparison parameters are power dissipation, bias current, input resistance, output resistance, and cut off frequency obtained from DC transfer characteristics and AC frequency response of proposed circuits.", "author_names": [ "Mahmut Tokmakci" ], "corpus_id": 45861730, "doc_id": "45861730", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "The comparative analysis of current mirror based CMOS current amplifiers", "venue": "IEICE Electron. Express", "year": 2007 }, { "abstract": "The AC current transfer ratios for BJT current mirrors operating with nanoampere DC bias currents have been measured and analysed. The new measurement technique uses current feedback topology instrumentation amplifiers to sense indirectly the input and output currents of a current mirror under test. Sample results are reported for the popular two transistor and Wilson current mirrors. The measured frequency response data show that bipolar integrated circuit current mirrors, biased at nanoampere DC currents, have current transfer ratios in the range 0.7 to 1 with sufficient bandwidth for use in micropower circuit design. There is close agreement between measured and theoretical data. However, the results of SPICE simulation deviate at very low currents, confirming previous reports of inadequacies in the BJT model under these conditions.", "author_names": [ "Mike Brinson", "Daniel J Faulkner" ], "corpus_id": 108633870, "doc_id": "108633870", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Measurement and analysis of BJT current mirror frequency response at low DC bias currents", "venue": "", "year": 1997 } ]
GaN mesfet model
[ { "abstract": "This paper presents a new model to study the static performances of a GaN metal epitaxial semiconductor field effect transistor (MESFET) based on the metal semiconductor interface state of the Schottky junction. The I V performances of MESFET under different channel lengths and different operating systems (pinch off or not) have been achieved by our model, which strictly depended on the electrical parameters, such as the drain gate capacity Cgd, the source gate capacity Cgs, the transconductance, and the conductance. To determine the accuracy of our model, root mean square (RMS) errors were calculated. In the experiment, the experimental data agree with our model. Also, the minimum value of the electrical parameter has been calculated to get the maximum cut off frequency for the GaN MESFET.", "author_names": [ "Xiaohong Li", "Ruirong Wang", "Tong Chen" ], "corpus_id": 116646069, "doc_id": "116646069", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Static performance model of GaN MESFET based on the interface state", "venue": "", "year": 2018 }, { "abstract": "A new two dimensional (2D) analytical model for a Triple Material Gate (TM) GaN MESFET has been proposed and modeled to suppress the short channel effects and improve the subthreshold behavior. The analytical model is based on a two dimensional analysis of the channel potential, threshold voltage and subthreshold swing factor for TM GaN MESFET is developed. The aim of this work is to demonstrate the improved subthreshold electrical performances exhibited by TM GaN MESFET over dual material gate and conventional single material gate MESFET. The results so obtained are verified and validated by the good agreement found with the 2D numerical simulations using the ATLAS device simulation software. The models developed in this paper will be very helpful to understand the device behavior in subthreshold regime for future circuit applications.", "author_names": [ "N Lakhdar", "Faycal Djeffal" ], "corpus_id": 110357197, "doc_id": "110357197", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A new two dimensional analytical subthreshold behavior model for submicron Triple Material Gate (TM) GaN MESFET", "venue": "", "year": 2014 }, { "abstract": "", "author_names": [ "S Nagaraj", "Ramin Roosta", "Robert D Conner" ], "corpus_id": 202691151, "doc_id": "202691151", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "CALIFORNIA STATE UNIVERSITY NORTHRIDGE Analytical Model of GaN MESFET's With Velocity Saturation and Negative Differential Resistance A graduate project submitted in fulfillment of the requirements For the degree of Master of Science in Electrical Engineering By", "venue": "", "year": 2015 }, { "abstract": "", "author_names": [ "S Nagaraj" ], "corpus_id": 112596138, "doc_id": "112596138", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Analytical Model of GaN MESFET's With Velocity Saturation and Negative Differential Resistance", "venue": "", "year": 2015 }, { "abstract": "", "author_names": [ "N Lakhdar" ], "corpus_id": 195276518, "doc_id": "195276518", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Erratum to: A new two dimensional analytical subthreshold behavior model for submicron Triple Material Gate (TM) GaN MESFET", "venue": "", "year": 2014 }, { "abstract": "A two dimensional (2D) analytical model is derived in this paper to predict the channel potential of MESFET. The model is based on two dimensional analytical solution of Poisson's equation with suitable boundary conditions. The analytical result is obtained and verified for GaN MESFET. The result of analytical model is almost similar to the simulation result obtained by Comsol Multiphysics. The variation of channel potential with respect to gate to source voltage, drain to source voltage and channel length is also shown. This model can be used for further device characterization and optimization.", "author_names": [ "Tanvir Ahmed", "M T A Khan", "M S Islam" ], "corpus_id": 38389381, "doc_id": "38389381", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Two dimensional analytical potential distribution model for GaN MESFET", "venue": "2012 International Conference on Devices, Circuits and Systems (ICDCS)", "year": 2012 }, { "abstract": "", "author_names": [ "Divakar Vedati" ], "corpus_id": 59135033, "doc_id": "59135033", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "An analytical model of drain induced barrier lowering effect for gallium nitride (GaN) MESFET's", "venue": "", "year": 2013 }, { "abstract": "", "author_names": [ "Ankithreddy Sudini" ], "corpus_id": 110457900, "doc_id": "110457900", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A capacitance model for Gallium Nitride (GaN) MESFET with a new concept of charge conversion", "venue": "", "year": 2013 }, { "abstract": "A novel nonlinear model for MESFET/HEMT devices is presented. The model can be applied to low power (GaAs) and high power (GaN) devices with equal success. The model provides accurate simulation of the static (DC) and dynamic (Pulsed) I V characteristics of the device over a wide bias and ambient temperature range (from i70 C to +70 C) without the need of an additional electro thermal sub circuit. This is an important issue in high power GaN HEMT devices where self heating and current collapse due to traps is a more serious problem. The parameter extraction strategy of the new model is simple to implement. The robustness of the model when performing harmonic balance simulation makes it suitable for RF and microwave designers. Experimental results presented demonstrate the accuracy of the model when simulating both the small signal and large signal behavior of the device over a wide range of frequency, bias and ambient temperature operating points. The model described has been implemented in the Advanced Design System (ADS) simulator to validate the proposed approach without convergence problems.", "author_names": [ "Mohamed Chaibi", "T Fernandez", "Asmae Mimouni", "J Rodriguez-Tellez", "Antonio Tazon", "Angel Mediavilla Sanchez" ], "corpus_id": 16279955, "doc_id": "16279955", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Nonlinear Modeling of Trapping and Thermal Effects on GaAs and GaN Mesfet/HEMT Devices", "venue": "", "year": 2012 }, { "abstract": "A physical analytical model is developed for the output current voltage characteristics and for describing the behavior of electrons in sub micron GaN MESFET's. A semi empirical formula has been proposed to approximate the electron drift velocity versus electric field in GaN by fitting it with the Monte Carlo simulation data. It gives a true physical description and an excellent approximation of the velocity field dependence in GaN revealing the presence of a velocity peak which is substantially higher than the saturation velocity at temperature close to 300 K and at typical doping concentration of 1017/cm3. The resulting I V curves are in excellent agreement with the experimental data. (c) 2006 WILEY VCH Verlag GmbH Co. KGaA, Weinheim)", "author_names": [ "Sneha Kabra", "Harsupreet Kaur", "Subhasis Haldar", "Mridula Gupta", "R S Gupta" ], "corpus_id": 123550967, "doc_id": "123550967", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "An analytical model for GaN MESFET's using new velocity field dependence", "venue": "", "year": 2006 } ]
Emerging device applications for semiconducting two-dimensional transition metal dichalcogenides
[ { "abstract": "With advances in exfoliation and synthetic techniques, atomically thin films of semiconducting transition metal dichalcogenides have recently been isolated and characterized. Their two dimensional structure, coupled with a direct band gap in the visible portion of the electromagnetic spectrum, suggests suitability for digital electronics and optoelectronics. Toward that end, several classes of high performance devices have been reported along with significant progress in understanding their physical properties. Here, we present a review of the architecture, operating principles, and physics of electronic and optoelectronic devices based on ultrathin transition metal dichalcogenide semiconductors. By critically assessing and comparing the performance of these devices with competing technologies, the merits and shortcomings of this emerging class of electronic materials are identified, thereby providing a roadmap for future development.", "author_names": [ "Deep Jariwala", "Vinod K Sangwan", "Lincoln J Lauhon", "Tobin J Marks", "Mark C Hersam" ], "corpus_id": 5409236, "doc_id": "5409236", "n_citations": 1757, "n_key_citations": 10, "score": 1, "title": "Emerging device applications for semiconducting two dimensional transition metal dichalcogenides.", "venue": "ACS nano", "year": 2014 }, { "abstract": "The emerging system of atomically thin materials with only a few atomic layer thickness opens the new research fields of optical science and device applications. The optically generated bound electron hole pairs (excitons and charged excitons) contribute to the novel optical properties in semiconducting atomically thin materials of monolayer transition metal dichalcogenides called as \"beyond graphene\" We describe our recent studies on novel optical science and application in atomically thin semiconducting transition metal dichalcogenides.", "author_names": [ "Kazunaii Matsuda" ], "corpus_id": 40379573, "doc_id": "40379573", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Optical properties and application of atomically thin two dimensional materials", "venue": "2017 24th International Workshop on Active Matrix Flatpanel Displays and Devices (AM FPD)", "year": 2017 }, { "abstract": "Recent experimental efforts in investigating low dimensional nanomaterials have spanned significantly beyond carbon nanotube (CNT) and graphene, which are often considered hallmarks of one and two dimensional (1&2D) nanostructures. Emerging layered nanomaterials, such as transition metal dichalcogenides (TMDC) and black phosphorus (P) have enabled new device functions and potential applications thanks to their intriguing material properties unavailable in CNT and graphene. In particular, nanoelectromechanical systems (NEMS) based on these new nanostructures exhibit new and interesting device properties. This paper describes the recent progresses in exploring and engineering atomically thin semiconducting crystals into a new class of two dimensional nanoelectromechanical systems, which hold promises for building novel nanoscale transducers. Exploration of resonant NEMS based on molybdenum disulfide (MoS2) reveals in these new nanoscale systems very broad dynamic range, rich nonlinear dynamics, and outstanding electrical tunability. Further, recent investigations show that black P NEMS offer the unique opportunity for harnessing the strong mechanical anisotropy in this nanocrystal composed of corrugated atomic sheets, demonstrating potential towards new device functions and applications that are unavailable to CNT and graphene based devices and systems.", "author_names": [ "Max Zenghui Wang" ], "corpus_id": 43031324, "doc_id": "43031324", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Nanoelectromechanical systems based on low dimensional nanomaterials: Beyond carbon nanotube and graphene nanomechanical resonators a brief review", "venue": "2016 IEEE 16th International Conference on Nanotechnology (IEEE NANO)", "year": 2016 }, { "abstract": "Two dimensional (2D) semiconducting transition metal dichalcogenides (TMDCs) and black phosphorus (BP) have beneficial electronic, optical, and physical properties at the few layer limit. As atomically thin materials, 2D TMDCs and BP are highly sensitive to their environment and chemical modification, resulting in a strong dependence of their properties on substrate effects, intrinsic defects, and extrinsic adsorbates. Furthermore, the integration of 2D semiconductors into electronic and optoelectronic devices introduces unique challenges at metal semiconductor and dielectric semiconductor interfaces. Here, we review emerging efforts to understand and exploit chemical effects to influence the properties of 2D TMDCs and BP. In some cases, surface chemistry leads to significant degradation, thus necessitating the development of robust passivation schemes. On the other hand, appropriately designed chemical modification can be used to beneficially tailor electronic properties, such as controlling doping levels and charge carrier concentrations. Overall, chemical methods allow substantial tunability of the properties of 2D TMDCs and BP, thereby enabling significant future opportunities to optimize performance for device applications.", "author_names": [ "Christopher R Ryder", "Joshua D Wood", "Spencer A Wells", "Mark C Hersam" ], "corpus_id": 206701061, "doc_id": "206701061", "n_citations": 168, "n_key_citations": 1, "score": 0, "title": "Chemically Tailoring Semiconducting Two Dimensional Transition Metal Dichalcogenides and Black Phosphorus.", "venue": "ACS nano", "year": 2016 }, { "abstract": "Over the past decade, two dimensional (2D) transition metal dichalcogenides (TMDCs) have attracted tremendous research interest for future electronics owing to their atomically thin thickness, compelling properties and various potential applications. However, interface engineering including contact optimization and channel modulations for 2D TMDCs represents fundamental challenges in ultimate performance of ultrathin electronics. This article provides a comprehensive overview of the basic understanding of contacts and channel engineering of 2D TMDCs and emerging electronics benefiting from these varying approaches. In particular, we elucidate multifarious contact engineering approaches such as edge contact, phase engineering and metal transfer to suppress the Fermi level pinning effect at the metal/TMDC interface, various channel treatment avenues such as van der Waals heterostructures, surface charge transfer doping to modulate the device properties, and as well the novel electronics constructed by interface engineering such as diodes, circuits and memories. Finally, we conclude this review by addressing the current challenges facing 2D TMDCs towards next generation electronics and offering our insights into future directions of this field.", "author_names": [ "Wugang Liao", "Siwen Zhao", "Fujin Li", "Cong Wang", "Yanqi Ge", "Huide Wang", "Shibo Wang", "Han Zhang" ], "corpus_id": 212408356, "doc_id": "212408356", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Interface engineering of two dimensional transition metal dichalcogenides towards next generation electronic devices: recent advances and challenges.", "venue": "Nanoscale horizons", "year": 2020 }, { "abstract": "Abstract Transition metal dichalcogenides (TMDCs) have attracted significant attention for their great potential in nano energy. TMDC layered materials represent a diverse and largely untapped source of 2D systems. High quality TMDC layers with an appropriate size, variable thickness, superior electronic and optical properties can be produced by the exfoliation or vapor phase deposition method. Semiconducting TMDC monolayers have been demonstrated feasible for various energy related applications, where their electronic properties and uniquely high surface areas offer opportunities for various applications such as nano generators, green electronics, electrocatalytic hydrogen generation and energy storage. In this review, we start from the structure, properties and preparation, followed by detailed discussions on the development of TMDC based nano energy applications.", "author_names": [ "Henan Li", "Yumeng Shi", "Ming-Hui Chiu", "Lain-Jong Li" ], "corpus_id": 137051812, "doc_id": "137051812", "n_citations": 148, "n_key_citations": 1, "score": 0, "title": "Emerging energy applications of two dimensional layered transition metal dichalcogenides", "venue": "", "year": 2015 }, { "abstract": "The fast growing earth population and the industrial growth of developing economies in Latin America and Asia have generated increasing air, water, and agricultural pollution in urban regions with consequences to human health. Most industrial sites are in urban regions, thus creating a challenge to ensure air quality and environment monitoring. Despite a growing diagnostic toolkit and a plethora of therapeutic interventions, a key challenge remains in the control of widespread diseases like cancer and diabetes. In the last decades, several semiconducting oxides have been used to detect dangerous or toxic gases. The excellent gas sensing performance of these gas sensor devices has been observed at high temperatures, which forbids their use for the detection of flammable and explosive gases. To overcome the problems such as selectivity, high sensitivity, and operation temperature, atomically thin transition metal dichalcogenides, which are two dimensional (2D) layered materials with large surface areas and tunable bandgaps, have emerged as a candidate for gas sensors. In the present book chapter, the recent advancement in the gas sensors, based on two dimensional (2D) transition metal dichalcogenides, has been comprehensively discussed. In the first section, the recent advances on synthesis process and the properties of these materials have been discussed. The next section depicts the layered transition metal dichalcogenides (TMDs) and their recent advances for application in the field of gas sensors. The challenges and opportunities in gas sensing are discussed, with emphasis on the sensing mechanisms. The third and fourth sections highlight the functionalization of TMDs with noble metals and other metal oxides to investigate the gas sensing properties. Finally, as summary, the prospects of these two dimensional transition metal dichalcogenides have been outlined for the development of highly efficient future generation gas sensors for accelerating the commercialization of the same.", "author_names": [ "Nirav Joshi", "Maria Luisa Braunger", "Flavio Makoto Shimizu", "Antonio Riul", "Osvaldo N Oliveira" ], "corpus_id": 219014876, "doc_id": "219014876", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Two Dimensional Transition Metal Dichalcogenides for Gas Sensing Applications", "venue": "", "year": 2020 }, { "abstract": "Abstract It is known that only in plane piezoelectricity exists in pristine two dimensional (2D) transition metal dichalcogenides (TMDs) In this study, we demonstrate the creation of strong out of plane piezoelectricity in semiconducting 2H MoTe2 flakes by an artificial atomic scale symmetry breaking. The atomic scale symmetry breaking associated with flexoelectricity was realized through Te vacancy formation by a simple thermal annealing of the 2D TMDs. The strong out of plane piezoelectricity was experimentally measured and confirmed by theoretical calculations. This strategy of atomic scale symmetry modulation for out of plane piezoelectricity can be easily applied to a broader class of 2D TMD materials that have not been used for applications with out of plane piezoelectricity. Accordingly, it can stimulate the expansion of practical energy device applications with 2D TMD materials.", "author_names": [ "Sera Kim", "Daehee Seol" ], "corpus_id": 139480969, "doc_id": "139480969", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Atomic scale symmetry breaking for out of plane piezoelectricity in two dimensional transition metal dichalcogenides", "venue": "Nano Energy", "year": 2019 }, { "abstract": "Raman spectroscopy is one of the most important optical techniques for the study of two dimensional systems, providing fundamental information for the development of applications using these materials in optoelectronics and valleytronics. The emerging area of two dimensional layered materials demands the characterization and understanding of the basic physical properties of the material under study and is indispensable to pave the way for the engineering of devices. In this review we cover the recent development of resonance Raman spectroscopy on transition metal dichalcogenides, discussing the exciton phonon coupling and intervalley double resonance Raman scattering process. A brief discussion of the effect of defects and disorder on the Raman spectra of these materials is also presented. The results of Raman spectroscopy in TMDs are compared to those observed in graphene, showing that this technique also provides physical information about TMDs that were previously reported in graphene systems. We also discuss the possible future perspectives and directions that the field may go to.", "author_names": [ "Bruno R Carvalho", "Marcos A Pimenta" ], "corpus_id": 219902351, "doc_id": "219902351", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Resonance Raman spectroscopy in semiconducting transition metal dichalcogenides: basic properties and perspectives", "venue": "", "year": 2020 }, { "abstract": "Two dimensional (2D) semiconductors, such as ultrathin layers of transition metal dichalcogenides (TMDs) offer a unique combination of electronic, optical and mechanical properties, and hold potential to enable a host of new device applications spanning from flexible/wearable (opto)electronics to energy harvesting and sensing technologies. A critical requirement for developing practical and reliable electronic devices based on semiconducting TMDs consists in achieving a full control over their charge carrier polarity and doping. Inconveniently, such a challenging task cannot be accomplished by means of well established doping techniques (e.g. ion implantation and diffusion) which unavoidably damage the 2D crystals resulting in degraded device performances. Nowadays, a number of alternatives are being investigated, including various (supra)molecular chemistry approaches relying on the combination of 2D semiconductors with electroactive donor/acceptor molecules. As yet, a large variety of molecular systems have been utilized for functionalizing 2D TMDs via both covalent and non covalent interactions. Such research endeavours enabled not only the tuning of the charge carrier doping but also the engineering of the optical, electronic, magnetic, thermal and sensing properties of semiconducting TMDs for specific device applications. Here, we will review the most enlightening recent advancements in experimental (supra)molecular chemistry methods for tailoring the properties of atomically thin TMDs in the form of substrate supported or solution dispersed nanosheets and we will discuss the opportunities and the challenges towards the realization of novel hybrid materials and devices based on 2D semiconductors and molecular systems.", "author_names": [ "Simone Bertolazzi", "Marco Gobbi", "Yuda Zhao", "Claudia Backes", "Paolo Samori" ], "corpus_id": 51717071, "doc_id": "51717071", "n_citations": 97, "n_key_citations": 0, "score": 0, "title": "Molecular chemistry approaches for tuning the properties of two dimensional transition metal dichalcogenides.", "venue": "Chemical Society reviews", "year": 2018 } ]
A Three-Phase Single-Sensor based Cuk-derived PFC Converter with Reduced Number of Components for More Electric Aircraft
[ { "abstract": "A new three phase Cuk derived power factor corrected (PFC) converter with only three switches for more electric aircraft is presented. The proposed converter benefits limited components for its operation, and only one semiconductor from each phase is in the current conduction path throughout the converter operation that substantially reduces the conduction losses leading to high efficiency and low converter thermal management. Further, the control effort required for converter operation is very less as all the three switches are driven by one gate signal. The converter output inductors are designed for discontinuous current operation for the entire converter power range to realize natural PFC at ac power source. The converter control is very simple, economical, and reliable since only one sensor is required for implementation. A detailed discussion on the converter steady state operation for one switching cycle is presented. The converter small signal model and the design expressions are derived to ease the converter control and the design. Further, the feasibility of the proposed scheme and the design are validated with the experimental results from a 2 kW laboratory prototype.", "author_names": [ "Sivanagaraju Gangavarapu", "Akshay Kumar Rathore" ], "corpus_id": 218777784, "doc_id": "218777784", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "A Three Phase Single Sensor Based Cuk Derived PFC Converter With Reduced Number of Components for More Electric Aircraft", "venue": "IEEE Transactions on Transportation Electrification", "year": 2020 }, { "abstract": "In more electric aircraft (MEA) three phase power factor correction (PFC) rectifiers of several kilowatts are required. In this paper, a three phase buck boost derived PFC converter with three switches and with input inductors connected in delta configuration for use in MEA is presented. The proposed converter is operated in a discontinuous conduction mode to achieve PFC at ac input. This avoids the inner current control loop which further eliminates the current sensors. It requires only one output voltage sensor unlike five sensors in conventional PFC converter for its control implementation. This makes the system cost effective, more reliable, and robust. A simple voltage control loop is used to generate the gate signals. The steady state operation of the converter and detailed design calculations are presented. For each power component, the analytical expressions for calculating the average and rms current ratings are derived to facilitate the converter design. The small signal model of the converter is presented to aid the controller design. The experimental results from a 2 kW laboratory prototype are presented to confirm the operation of the proposed converter. An input power factor of 0.999, an input current total harmonic distortion of as low as 2.76% and a high conversion efficiency of 96% are achieved from the prototype.", "author_names": [ "Sivanagaraju Gangavarapu", "Akshay Kumar Rathore" ], "corpus_id": 115873810, "doc_id": "115873810", "n_citations": 18, "n_key_citations": 4, "score": 0, "title": "Three Phase Buck Boost Derived PFC Converter for More Electric Aircraft", "venue": "IEEE Transactions on Power Electronics", "year": 2019 }, { "abstract": "Three phase AC DC converters have been developed to a matured level with improved power quality in terms of power factor correction, reduced total harmonic distortion at input AC mains, and regulated DC output in buck, boost, buck boost, multilevel, and multipulse modes with unidirectional and bidirectional power flow. This paper presents an exhaustive review of three phase improved power quality AC DC converters (IPQCs) configurations, control strategies, selection of components, comparative factors, recent trends, their suitability, and selection for specific applications. It is aimed at presenting a state of the art on the IPQC technology to researchers, designers, and application engineers dealing with three phase AC DC converters. A classified list of around 450 research articles on IPQCs is also appended for a quick reference.", "author_names": [ "Bhim Singh", "Brij N Singh", "Ambrish Chandra", "Kamal Al-Haddad", "Ashish Pandey", "Dwarkadas Pralhaddas Kothari" ], "corpus_id": 28060742, "doc_id": "28060742", "n_citations": 1088, "n_key_citations": 23, "score": 0, "title": "A review of three phase improved power quality AC DC converters", "venue": "IEEE Transactions on Industrial Electronics", "year": 2004 }, { "abstract": "In the first part of this paper, three phase power factor correction (PFC) rectifier topologies with sinusoidal input currents and controlled output voltage are derived from known single phase PFC rectifier systems and/or passive three phase diode rectifiers. The systems are classified into hybrid and fully active pulsewidth modulation boost type or buck type rectifiers, and their functionality and basic control concepts are briefly described. This facilitates the understanding of the operating principle of three phase PFC rectifiers starting from single phase systems, and organizes and completes the knowledge base with a new hybrid three phase buck type PFC rectifier topology denominated as Swiss Rectifier. Finally, core topics of future research on three phase PFC rectifier systems are discussed, such as the analysis of novel hybrid buck type PFC rectifier topologies, the direct input current control of buck type systems, and the multi objective optimization of PFC rectifier systems. The second part of this paper is dedicated to a comparative evaluation of four rectifier systems offering a high potential for industrial applications based on simple and demonstrative performance metrics concerning the semiconductor stresses, the loading and volume of the main passive components, the differential mode and common mode electromagnetic interference noise level, and ultimately the achievable converter efficiency and power density. The results are substantiated with selected examples of hardware prototypes that are optimized for efficiency and/or power density.", "author_names": [ "Johann Walter Kolar", "Thomas Friedli" ], "corpus_id": 52802218, "doc_id": "52802218", "n_citations": 447, "n_key_citations": 17, "score": 0, "title": "The Essence of Three Phase PFC Rectifier Systems Part I", "venue": "IEEE Transactions on Power Electronics", "year": 2013 }, { "abstract": "This paper presents an integrated control strategy to achieve fast start up and enable wide input frequency operation in a three phase six switch power factor correction (PFC) converter. Limiting the inrush current with simultaneously minimizing the start up time is achieved by implementing a nonlinear compensator in the voltage control loop. In addition, the concerning issues regarding unity PFC operation with an accurate reference tracking in a system with wide input frequency variation (typical for more electric aircraft) are resolved by a second order compensator integrated with a state feedback controller in the current loop. For a proof of concept verification, a hardware prototype of 6 kW, three phase six switch PFC is developed and tested with the proposed integrated control strategy in a wide source frequency range (360 800 Hz) ac input that shows perfect unity power factor operation throughout. Both the start up time and inrush current are reduced to \\text{50} of their values in conventional PI compensation.", "author_names": [ "Ayan Mallik", "Alireza Khaligh" ], "corpus_id": 23187511, "doc_id": "23187511", "n_citations": 9, "n_key_citations": 1, "score": 0, "title": "An Integrated Control Strategy for a Fast Start Up and Wide Range Input Frequency Operation of a Three Phase Boost Type PFC Converter for More Electric Aircraft", "venue": "IEEE Transactions on Vehicular Technology", "year": 2017 }, { "abstract": "This article analyzes a three phase single stage isolated flyback based power factor correction converter and presents a novel clamping circuit to capture the transformers leakage inductance energy. The converter unity power factor operation is obtained by using the inherent resistance property of discontinuous conduction mode. Thus, the input current shaping circuit is eliminated and resulted in a single loop control system. Therefore, the converter control circuit requires only one sensor, which decreases the system cost, and also increases the system robustness to high frequency noise. With the proposed clamping circuit, the transformers leakage inductance energy is successfully captured in clamping capacitor, and thereby, it is fed to the dc load by using an auxiliary two switch forward converter which enhanced the overall operating efficiency of a converter. The converter detailed steady state operation and the design considerations are presented. Each power component voltage stress expressions are derived to simplify the converter design, and the converter small signal model is presented to help the controller design. The novelty and performance of the converter is verified by both simulation and experimentation.", "author_names": [ "Sivanagaraju Gangavarapu", "Akshay Kumar Rathore", "Vinod Khadkikar" ], "corpus_id": 203993796, "doc_id": "203993796", "n_citations": 3, "n_key_citations": 1, "score": 0, "title": "High Efficiency Three Phase Single Stage Isolated Flyback Based PFC Converter With a Novel Clamping Circuit", "venue": "IEEE Transactions on Industry Applications", "year": 2020 }, { "abstract": "This article presents a three phase single stage isolated flyback based power factor correction (PFC) converter with a clamping circuit to recover the transformer leakage inductance energy for more electric aircraft application. With the proposed clamping circuit, the transformers' leakage inductance energy is successfully captured in clamping capacitor, and subsequently, a constant power 28 V secondary supply is derived by using a two switch forward converter to improve the converter overall efficiency. The converter unity power factor (UPF) operation is obtained by using the inherent resistance property of discontinuous conduction mode (DCM) Hence, the input current shaping circuit is eliminated and resulted in a single loop control system. Thus, the converter control circuit requires only one sensor, which decreases the system cost and increases the system reliability and robustness. In addition, the converter provides fault tolerant operation for single phase loss. The converter is analyzed and the design equations are explained in detail. The voltage and current stress equations for all power components are derived and validated with the simulation. The novelty and the operation of the converter are demonstrated with the experimental results from a 2 kW laboratory prototype.", "author_names": [ "Sivanagaraju Gangavarapu", "Akshay Kumar Rathore Gae" ], "corpus_id": 210513300, "doc_id": "210513300", "n_citations": 3, "n_key_citations": 1, "score": 0, "title": "A Three Phase Single Stage Isolated Flyback Based PFC Converter With Leakage Energy Recovery Clamping Circuit", "venue": "IEEE Transactions on Transportation Electrification", "year": 2019 }, { "abstract": "In this paper, a new front end ac dc bridgeless interleaved power factor correction topology is proposed for level II plug in hybrid electric vehicle (PHEV) battery charging. The topology can achieve high efficiency, which is critical for minimizing the charger size, PHEV charging time and the amount and cost of electricity drawn from the utility. In addition, a detailed analytical model for this topology is presented, enabling the calculation of the converter power losses and efficiency. Experimental and simulation results are included for a prototype boost converter converting universal ac input voltage (85 265 V) to 400 V dc output at up to 3.4 kW load. The experimental results demonstrate a power factor greater than 0.99 from 750 W to 3.4 kW, THD less than 5% from half load to full load and a peak efficiency of 98.9% at 70 kHz switching frequency, 265 V input and 1.2 kW load.", "author_names": [ "Fariborz Musavi", "Wilson Eberle", "William G Dunford" ], "corpus_id": 8737494, "doc_id": "8737494", "n_citations": 294, "n_key_citations": 9, "score": 0, "title": "A High Performance Single Phase Bridgeless Interleaved PFC Converter for Plug in Hybrid Electric Vehicle Battery Chargers", "venue": "IEEE Transactions on Industry Applications", "year": 2011 }, { "abstract": "In this paper, a three phase isolated flyback based single stage power factor corrected (PFC) converter with a novel clamping circuit for aircraft application is presented. The steady state operation and design calculations of the converter are presented in detail. The converter is operated in discontinuous conduction mode (DCM) due to its inherent advantages such as PFC, reduced number of sensors, zero diode reverse recovery losses and zero current switching on. The converter requires only one sensor, which makes the system cost effective, more reliable and robust. By using the proposed clamping circuit, the transformers leakage inductance energy is captured successfully in a clamping capacitor, and subsequently a secondary 24V DC supply is derived by connecting a forward converter across the clamping capacitor. The performance of the converter is validated through the simulation and experimental results.", "author_names": [ "Sivanagaraju Gangavarapu", "Akshay Kumar Rathore" ], "corpus_id": 169032883, "doc_id": "169032883", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Analysis and Design of Three Phase Single Stage Isolated Flyback Based PFC Converter with a Novel Clamping Circuit", "venue": "2019 IEEE Applied Power Electronics Conference and Exposition (APEC)", "year": 2019 }, { "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": 0, "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 } ]
Transport properties of near surface InAs two-dimensional heterostructures
[ { "abstract": "Two dimensional electron systems confined to the surface of narrowband semiconductors have attracted great interest since they can easily integrate with superconductivity (or ferromagnetism) enabling new possibilities in hybrid device architectures and study of exotic states in proximity to superconductors. In this work, we study indium arsenide heterostructures where a combination of a clean interface with superconductivity, high mobility, and spin orbit coupling can be achieved. The weak antilocalization measurements indicate the presence of strong spin orbit coupling at high densities. We study the magnetotransport as a function of top barrier and density and report a clear observation of integer quantum Hall states. We report improved electron mobility reaching up to 44 000 cm2/Vs in undoped heterostructures and well developed integer quantum Hall states starting as low as 2.5 T.Two dimensional electron systems confined to the surface of narrowband semiconductors have attracted great interest since they can easily integrate with superconductivity (or ferromagnetism) enabling new possibilities in hybrid device architectures and study of exotic states in proximity to superconductors. In this work, we study indium arsenide heterostructures where a combination of a clean interface with superconductivity, high mobility, and spin orbit coupling can be achieved. The weak antilocalization measurements indicate the presence of strong spin orbit coupling at high densities. We study the magnetotransport as a function of top barrier and density and report a clear observation of integer quantum Hall states. We report improved electron mobility reaching up to 44 000 cm2/Vs in undoped heterostructures and well developed integer quantum Hall states starting as low as 2.5 T.", "author_names": [ "Kaushini S Wickramasinghe", "William Mayer", "Joseph Yuan", "Tri Tuan Nguyen", "Lu Jiao", "Vladimir E Manucharyan", "Javad Shabani" ], "corpus_id": 119203372, "doc_id": "119203372", "n_citations": 18, "n_key_citations": 0, "score": 1, "title": "Transport properties of near surface InAs two dimensional heterostructures", "venue": "", "year": 2018 }, { "abstract": "", "author_names": [ "Joseph Yuan", "William Mayer", "Kaushini S Wickramasinghe", "Javad Shabani" ], "corpus_id": 140097961, "doc_id": "140097961", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Transport Properties Of Near Surface Quantum Wells In InAs Heterostructures", "venue": "", "year": 2018 }, { "abstract": "Near surface InAs two dimensional electron gas (2DEG) systems have great potential for realizing networks of multiple Majorana zero modes towards a scalable topological quantum computer. Improving mobility in the near surface 2DEGs is beneficial for stable topological superconducting states as well as for correlation of multiple Majorana zero modes in a complex network. Here, we investigate near surface InAs 2DEGs (13 nm away from the surface) grown on GaSb(001) substrates, whose lattice constant is closely matched to InAs, by molecular beam epitaxy. The effect of 10 nm thick top barrier to the mobility is studied by comparing Al$_{0.9}$Ga$_{0.1}$Sb and In$_{0.75}$Ga$_{0.25}$As as a top barrier on otherwise identical InAs quantum wells grown with identical bottom barrier and buffer layers. A 3 nm thick capping layer on Al$_{0.9}$Ga$_{0.1}$Sb top barrier also affects the 2DEG electronic transport properties by modifying scattering from 2D remote ionized impurities at the surface. The highest transport mobility of 650,000 cm$^2$/Vs with an electron density of 3.81 \\times$ 10${11} cm$ 2} was observed in an InAs 2DEG with an Al$_{0.9}$Ga$_{0.1}$Sb top barrier and an In$_{0.75}$Ga$_{0.25}$As capping layer. Analysis of Shubnikov de Haas oscillations in the high mobility sample suggests that long range scattering, such as remote ionized impurity scattering, is the dominant scattering mechanism in the InAs 2DEGs grown on GaSb(001) substrates. In comparison to InAs quantum wells grown on lattice mismatched InP, the ones grown on GaSb show smoother surface morphology and higher quantum mobility. However, In$_{0.75}$Ga$_{0.25}$As top barrier in InAs quantum well grown on GaSb limits the transport mobility by charged dislocations formed in it, in addition to the major contribution to scattering from the alloy scattering.", "author_names": [ "Joon Sue Lee", "Borzoyeh Shojaei", "Mihir Pendharkar", "Mayer Feldman", "Kunal Mukherjee", "Chris J Palmstrom" ], "corpus_id": 119456943, "doc_id": "119456943", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Contribution of top barrier materials to high mobility in near surface InAs quantum wells grown on GaSb(001)", "venue": "", "year": 2018 }, { "abstract": "We have investigated the anisotropic transport behavior of InAs/AlSb heterostructures grown on a (001) InP substrate. An electrical analysis showed anisotropic sheet resistance Rsh and electron mobility mn in the two dimensional electron gas (2DEG) Hall measurements demonstrated an enhanced anisotropy in mn when cooled from room temperature to 2 K. High electron mobility transistors exhibited 27% higher maximum drain current IDS and 23% higher peak transconductance gm when oriented along the [1 10] direction. The anisotropic transport behavior in the 2DEG was correlated with an asymmetric dislocation pattern observed in the surface morphology and by cross sectional microscopy analysis of the InAs/AlSb heterostructure.", "author_names": [ "Giuseppe Moschetti", "Huan Zhao", "Per Ake Nilsson", "Shumin Wang", "Alexey Kalabukhov", "Gilles Dambrine", "S Bollaert", "Ludovic Desplanque", "Xavier Wallart", "Jan V Grahn" ], "corpus_id": 121775297, "doc_id": "121775297", "n_citations": 19, "n_key_citations": 0, "score": 0, "title": "Anisotropic transport properties in InAs/AlSb heterostructures", "venue": "", "year": 2010 }, { "abstract": "Abstract We have studied the magnetoresistance of a near surface two dimensional electron gas (2DEG) in the presence of a random magnetic field produced by CoPd multilayers deposited onto the surface of the heterostructure. This novel method allows us to switch the random field on and off by applying an external magnetic field and also to control the amplitude and correlation length of the random field by varying the growth parameters of the multilayers. The presence of the random field is confirmed by quenching of the Shubnikov de Haas oscillations and we see an enhanced magnetoresistance which can be interpreted semi classically. We also observe other unusual features which may be quantum in origin.", "author_names": [ "Andrew W Rushforth", "B L Gallagher", "P C Main", "A C Neumann", "Christopher H Marrows", "I Zoller", "Mark A Howson", "B J Hickey", "Mohamed Henini" ], "corpus_id": 122117467, "doc_id": "122117467", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Transport properties of a two dimensional electron gas due to a spatially random magnetic field", "venue": "", "year": 2000 }, { "abstract": "We have studied the magnetoresistance of a near surface two dimensional electron gas (2DEG) in the presence of a random magnetic eld produced by CoPd multilayers deposited onto the surface of the heterostructure. This novel method allows us to switch the random eld on and o by applying an external magnetic eld and also to control the amplitude and correlation length of the random eld by varying the growth parameters of the multilayers. The presence of the random eld is con rmed by quenching of the Shubnikov de Haas oscillations and we see an enhanced magnetoresistance which can be interpreted semi classically. We also observe other unusual features which may be quantum in origin. 2000 Elsevier Science B.V. All rights reserved. PACS: 72.20.My; 73.50.Jt; 75.70 i", "author_names": [ "", "A W Rushfortha", "B L Gallaghera", "P C Maina", "A C Neumanna", "C H Marrowsb", "I Zollerb", "M A Howsonb", "B J Hickeyb", "M Heninia" ], "corpus_id": 56068747, "doc_id": "56068747", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Transport properties of a two dimensional electron gas due to a spatially randommagnetic eld", "venue": "", "year": 2000 }, { "abstract": "The isolation of a growing number of two dimensional (2D) materials has inspired worldwide efforts to integrate distinct 2D materials into van der Waals (vdW) heterostructures. While a tremendous amount of research activity has occurred in assembling disparate 2D materials into \"all 2D\" van der Waals heterostructures, this concept is not limited to 2D materials alone. Given that any passivated, dangling bond free surface will interact with another via vdW forces, the vdW heterostructure concept can be extended to include the integration of 2D materials with non 2D materials that adhere primarily through noncovalent interactions. In the first part of this talk I will present our work on emerging mixed dimensional (2D nD, where n is 0, 1 or 3) heterostructure devices performed at Northwestern University. I will present two distinct examples of gate tunable p n heterojunctions 1. Single layer n type MoS2 (2D) combined with p type semiconducting single walled carbon nanotubes (1D) and 2. Single layer MoS2 combined with 0D molecular semiconductor, pentacene. I will present the unique electrical properties, underlying charge transport mechanisms and photocurrent responses in both the above systems using a variety of scanning probe microscopy techniques as well as computational analysis. This work shows that van der Waals interactions are robust across different dimensionalities of materials and can allow fabrication of semiconductor devices with unique geometries and properties unforeseen in bulk semiconductors. Finally, I will briefly discuss our recent work from Caltech on near unity absorption in atomically thin photovoltaic devices.", "author_names": [ "Deep Jariwala" ], "corpus_id": 100308554, "doc_id": "100308554", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Mixed Dimensional Van der Waals Heterostructures for Opto Electronics.", "venue": "", "year": 2017 }, { "abstract": "Molecular self assembly is a well known technique to create highly functional nanostructures on surfaces. Self assembly on two dimensional (2D) materials is a developing field driven by the interest in functionalization of 2D materials in order to tune their electronic properties. This has resulted in the discovery of several rich and interesting phenomena. Here, we review this progress with an emphasis on the electronic properties of the adsorbates and the substrate in well defined systems, as unveiled by scanning tunneling microscopy. The review covers three aspects of the self assembly. The first one focuses on non covalent self assembly dealing with site selectivity due to inherent moire pattern present on 2D materials grown on substrates. We also see that modification of intermolecular interactions and molecule substrate interactions influences the assembly drastically and that 2D materials can also be used as a platform to carry out covalent and metal coordinated assembly. The second part deals with the electronic properties of molecules adsorbed on 2D materials. By virtue of being inert and possessing low density of states near the Fermi level, 2D materials decouple molecules electronically from the underlying metal substrate and allow high resolution spectroscopy and imaging of molecular orbitals. The moire pattern on the 2D materials causes site selective gating and charging of molecules in some cases. The last section covers the effects of self assembled, acceptor and donor type, organic molecules on the electronic properties of graphene as revealed by spectroscopy and electrical transport measurements. Non covalent functionalization of 2D materials has already been applied for their application as catalysts and sensors. With the current surge of activity on building van der Waals heterostructures from atomically thin crystals, molecular self assembly has the potential to add an extra level of flexibility and functionality for applications ranging from flexible electronics and OLEDs to novel electronic devices and spintronics.", "author_names": [ "Avijit Kumar", "Kaustuv Banerjee", "Peter Liljeroth" ], "corpus_id": 33866737, "doc_id": "33866737", "n_citations": 64, "n_key_citations": 0, "score": 0, "title": "Molecular assembly on two dimensional materials.", "venue": "Nanotechnology", "year": 2017 }, { "abstract": "A bilayer structure of indium arsenide (InAs) and gallium antimonide (GaSb) has been proposed as a two dimensional (2D) electronic system tunable to different states of matter namely the trivial and the topological insulator (TI) phases. 2D TI which is also called quantum spin Hall (QSH) insulator is characterized by an insulating bulk and non dissipative counterpropagating edge states with opposite spin polarizations. These features identify the quantum spin Hall effect where the helical edge states are topologically immune against backscattering guaranteed by time reversal symmetry. Lowtemperature electronic transport measurements may serve to examine the transport properties of InAs/GaSb quantum wells and therefore to inquire into the essence of its bulk and edge behavior. This work is aimed to study the constituents necessary to obtain a robust quantum spin Hall insulator based on InAs/GaSb bilayer heterostructure. We focus on the localization phenomena in InAs/GaSb bilayer quantum wells which are intentionally disordered by silicon atoms. We observed that Si doping near the InAs/GaSb interface significantly alters the transport behavior of these heterostructures. First, we investigated the localization of trivial edge states driven by silicon impurities. As confirmed by recent experimental studies, conductance quantization due to nontrivial edge states, which is the most significant highlight of the QSH effect is obscured by spurious conductivity arising from trivial edge states. In this thesis, we present an experimental observation of the strong localization of trivial edge modes in an InAs/GaSb heterostructure which is weakly disordered by silicon delta like dopants within the InAs layer. The edge conduction which is characterized by a temperature independent behavior at low temperatures and a power law at high temperatures is observed to be exponentially scaled with the length of the edge. Results of comprehensive analyses on measurements done with a range of devices are in agreement with the localization theories in quasi onedimensional electronic systems. Spin orbit interaction is one of the main ingredients of the TIs and in particular in disordered and thus low mobility electronic systems it leads to a weak anti localization characteristic in low field magnetoconductance measurements. As the charge carriers are depleted using a top gate electrode, we observed a crossover from weak anti localization (WAL) to weak localization (WL) This occurs when the dephasing length decreases below the spin orbit characteristic length as a result of enhanced electron electron interactions at lower carrier concentrations. The same crossover is observed with increasing temperature. The linear temperature behavior of inelastic scattering rate indicates that the dominant phase breaking mechanism in our 2D system is due to electron electron interactions. Finally, we compare three heterostructures (Wafers A, B, and C) all delta doped with silicon atoms at different spatial positions in the growth direction near the InAs/GaSb interface. We found the transport behavior of these heterostructures to be very different from each other which can be attributed to the vertical position of disorder within the layered structures. Since the silicon atoms are donors to InAs and acceptors to GaSb, it matters where they are located with respect to the InAs/GaSb interface considering the interfacial effects and potential fluctuations induced by impurities", "author_names": [ "Vahid Sazgari Ardakani" ], "corpus_id": 216606195, "doc_id": "216606195", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Localization phenomena in INAS/GASB composite quantum wells with disorder", "venue": "", "year": 2019 }, { "abstract": "Abstract We discuss structural and electrical properties of AlAs x Sb 1 x bulk layers and InAs/AlAs x Sb 1 x heterostructures grown by molecular beam epitaxy over a wide range of composition (0 x 0.4) We demonstrate the strong sensitivity of the structural quality and the composition of Al(As,Sb) on growth parameters such as substrate temperature, As Sb flux ratio, as well as total group V flux, and discuss the influence of a miscibility gap on the molecular beam epitaxial growth of Al(As,Sb) We also find that both the composition and the growth temperature strongly influence the surface morphology: Al(As,Sb) especially when grown at low substrate temperature appears to grow in an island coalescence mode rather than in a two dimensional manner as it does for pure AlAs or AlSb. The electrical transport along AlSb/InAs/Al(As,Sb) quantum wells is strongly influenced by the growth temperature of Al(As,Sb) and we observe the formation of additional defects when the top barrier was grown at low substrate temperature. The transport across InAs/Al(As,Sb) heterojunctions was found to depend on both the growth temperature and the arsenic composition. An increase in arsenic composition results in a strongly decreased current across the heterojunction. From ballistic electron emission spectroscopy experiments, we confirm the transition from a staggered band lineup for InAs/AlSb to a straddled band lineup for InAs/AlAs x Sb 1 x for x =0.16.", "author_names": [ "H Blank", "S K Mathis", "Eric M Hall", "S Bhargava", "Alexander Behres", "Michael Heuken", "Herbert Kroemer", "Venkatesh Narayanamurti" ], "corpus_id": 97426279, "doc_id": "97426279", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Al(As,Sb) heterobarriers on InAs: growth, structural properties and electrical transport", "venue": "", "year": 1998 } ]
Evaluation of switching performance ofSiC devices inPWM inverter-fed induction motor drives
[ { "abstract": "Double pulse test (DPT) is a widely accepted method to evaluate the switching characteristics of semiconductor switches, including SiC devices. However, the observed switching performance of SiC devices in a PWM inverter for induction motor drives (IMD) is almost always worse than the DPT characterization, with slower switching speed, more switching losses, and more serious parasitic ringing. This paper systematically investigates the factors that limit the SiC switching performance from both the motor side and inverter side, including the load characteristics of induction motor/power cable, two more phase legs for the three phase PWM inverter as compared to the DPT, and the parasitic capacitive coupling effect between power devices and heat sink. Based on the three phase PWM inverter with 1200 V SiC MOSFETs, the test results show that the induction motor, especially with a relatively long power cable, will significantly impact the switching performance, leading to switching time increase by a factor of 2, switching loss increase up to 30% and serious parasitic ringing with 1.5 ms duration as compared to that tested by DPT. In addition, the interactions among the three phase legs cannot be ignored unless the decoupling capacitors are mounted close to each phase leg to support the dc bus voltage during switching transients. Also, the coupling capacitance induced by the heat sink equivalently increases the junction capacitance of power devices. However, its influence on the switching behavior in the motor drives is small considering the relatively large capacitance of the motor load.", "author_names": [ "Zheyu Zhang", "Fred Wang", "Leon M Tolbert", "Benjamin J Blalock", "Daniel J Costinett" ], "corpus_id": 22448915, "doc_id": "22448915", "n_citations": 118, "n_key_citations": 4, "score": 1, "title": "Evaluation of switching performance of SiC devices in PWM inverter fed induction motor drives", "venue": "2014 IEEE Energy Conversion Congress and Exposition (ECCE)", "year": 2014 }, { "abstract": "", "author_names": [ "Zheyu Zhang", "Fred Wang", "Leon M Tolbert", "Benjamin J Blalock", "Daniel J Costinett" ], "corpus_id": 112946657, "doc_id": "112946657", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Evaluation of switching performance of SiC devices in PWM inverter fed induction motor drives", "venue": "", "year": 2014 }, { "abstract": "The dual inverter fed Open End Winding Induction Motor drive offers interesting possibilities for multilevel inversion. It needs two isolated power supplies to feed individual inverters to avoid the flow of zero sequence current. Three Space Vector PWM schemes have been reported in the earlier literature, which facilitate the operation of the dual inverter drive with a single power supply. This paper critically compares the performance of these three Space Vector PWM techniques for a dual inverter fed Open End Winding Induction Motor drive, which requires only one DC power supply. The criteria of comparison are: (i) the Total Harmonic Distortion (THD) in the voltage waveform (ii) the Total Harmonic Distortion (THD) in the phase current waveform (iii) RMS value of the stator flux ripple and (iv) switching and conduction losses of the switching devices. The relative merits and demerits of each SVPWM technique in these four aspects are presented. The performance of dual inverter fed OEWIM drive with two isolated DC power supplies in these four aspects is used as a benchmark for comparison.", "author_names": [ "Reddy Srinivas Rao", "B Naga Chaitanya", "N Saichand", "Veeramraju Tirumala Somasekhar" ], "corpus_id": 3558558, "doc_id": "3558558", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Comparative evaluation of SVPWM strategies for a dual inverter fed open end winding induction motor drive with a single DC power supply", "venue": "IECON 2014 40th Annual Conference of the IEEE Industrial Electronics Society", "year": 2014 }, { "abstract": "The development of advantageous power electronic switching devices such as insulated gate bipolar transistors (IGBTs) has made it possible for the inverter to realize high frequency switching operation and the effective performance of pulse width modulated (PWM) inverters for driving induction motors. On the other side, the high dv/dt of IGBT PWM inverters appears across the first few turns of winding, which may result in premature motor failures. Thus, the techniques to improve insulation characteristics are required to withstand the damaging pulses from the PWM drives. In this paper, the detailed insulation test results of 19 low voltage induction motors are presented. Five different types of insulation techniques are applied to 19 motors. The insulation characteristics are analyzed by performing partial discharge, discharge inception voltage, dissipation factor, and breakdown tests by high voltage pulses are performed.", "author_names": [ "Don-Ha Hwang Don-Ha Hwang", "Jeong-Woo Jeon Jeong-Woo Jeon", "Yong-Joo Kim Yong-Joo Kim", "Sung-Woo Bae Sung-Woo Bae", "Dong-Hee Kim Dong-Hee Kim", "Min-Huei Kim Min-Huei Kim", "In-Woo Lee In-Woo Lee" ], "corpus_id": 230510745, "doc_id": "230510745", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Evaluation of insulation systems for IGBT PWM inverter fed low voltage induction motors", "venue": "Industrial Electronics, 2002. ISIE 2002. Proceedings of the 2002 IEEE International Symposium on", "year": 2002 }, { "abstract": "In recent years, multilevel inverters have gained much attention in the application areas of medium voltage and high power owing to their various advantages such as lower common mode voltage, lower voltage stress on power switches, lower dv/dt ratio to supply lower harmonic contents in output voltage and current. This paper presents the simulation and implementation of multilevel inverter fed induction motor drive. The output harmonic content is reduced by using multilevel inverter. The proposed seven,twenty three,twenty seven and thirty three level cascaded Hbridge multilevel inverters require less number of components to obtain same number of voltage levels when compared to diode clamped and flying capacitor type methods. Due to that, the switching loss gets reduced as same like the harmonic distortion occurs in the motor drive gets reduced. Also, it generally regularizes the stair case voltage waveform from several dc sources which has reduced harmonic content. The operational principle and key waveforms are analyzed and the performance of the proposed multilevel inverter is evaluated from the simulation results. The results has been compared to that of the existing techniques and found to be quite better than the existing ones.", "author_names": [ "B N Lakshmi Pravallika", "Appa Rao", "Sk Mohiddin" ], "corpus_id": 216003482, "doc_id": "216003482", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Reduction Of Power Electronic Devices In Multilevel Inverter For Higher Voltage Level Fed With Induction Motor Drive", "venue": "", "year": 2016 }, { "abstract": "In this paper, a hybrid twenty five level inverter topology for an OEWIM (Open End Winding Induction Motor) drive is proposed. In this topology, one end of OEWIM is fed by a FC based hybrid five level inverter and other end is connected to a symmetrical five level inverter. The hybrid five level inverter is achieved by cascading a three level flying capacitor inverter with capacitor fed H bridge. The symmetrical five level inverter is obtained by cascade connection of four 2 level inverters with equal DC link voltages. The combined effect of five level hybrid and five level symmetrical inverters generate twenty five distinct levels in the phase voltage. In this proposed topology, a total of 3,43,000 space phasor combinations are accessible; hence using switching redundancies, the capacitor voltages can be maintained at desired levels. The proposed topology requires only 48 switching devices, as compared to conventional topologies that require 144 switches and fully eliminates the requirement of clamping diodes, which are required in NPC inverter. It, also, requires only 6 capacitors unlike to 828 capacitors required in twenty five level FC inverter and 5 DC power supply sources as compared to twenty five level CHB inverter that require 36 DC power supply sources. Simulation study is carried out to evaluate the performance of the proposed inverter and results are presented.", "author_names": [ "Anoop Kumar Kanaujia", "Sanjiv Kumar" ], "corpus_id": 208037262, "doc_id": "208037262", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Hybrid Twenty Five level Inverter for an Open End Winding Induction Motor (OEWIM) Drive", "venue": "2018 2nd IEEE International Conference on Power Electronics, Intelligent Control and Energy Systems (ICPEICES)", "year": 2018 }, { "abstract": "Multilevel inverters are gaining popularity in high power applications. This paper proposes a new ladder type structure of cascaded three phase multilevel inverter with reduced number of power semiconductor devices which is used to drive the induction motor. The ultimate aim of the paper is to produce multiple output levels with minimum number of semiconductor devices. This paper uses only 11 switches along with 3 diodes and 4 asymmetrical sources to produce an output voltage of 21 levels. The modulation technique plays a major role in commutation of the switches. Here we implement the multicarrier level shifting pulse width modulation technique to produce the commutation signals for the inverter. The proposed multilevel inverter is used to drive the three phase induction motor. The mathematical modeling of three phase induction motor is done using Simulink. Furthermore the PI and fuzzy logic controllers are also used to produce the reference waveform of the level shifting technique which in turn produces the commutation signals of the proposed multilevel converter. The controllers are used to control the speed of the induction motor. The effectiveness of the proposed system is proved with the help of simulation. The simulation is performed in MATLAB/Simulink. From the simulation results, it shows that the proposed multilevel inverter works properly to generate the multilevel output waveform with minimum number of semiconductor devices. The PI and fuzzy logic controller performances are evaluated using the results which indicate that with the help of controllers the harmonics has been reduced and the speed control of induction motor is achieved under different loading conditions.", "author_names": [ "A Abdul Namith", "T S Sivakumaran" ], "corpus_id": 54040131, "doc_id": "54040131", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Novel Asymmetric Three Phase Cascaded 21 Level Inverter Fed Induction Motor Using Multicarrier PWM with PI and Fuzzy Controller", "venue": "", "year": 2016 }, { "abstract": "At present nine level PWM inverters are introduced in industrial drives, for interconnecting the renewable energy sources into the grid supply and traction motor drives, where the high and medium voltage levels. This paper presents an attempt made to evaluate the performance of 9 level cascaded inverter supplying power to a 1 O induction motor using computer simulation. Mathematical modeling of the system derived using equivalent circuit and the device operations. MATLABI Simulink based performance study completed. A novel technique used for modulation process to generates the pulses. These are applying to the gate circuit of the solid state switches are used to configure the nine level inverter. Simulation study completed using ODE 23 solver and results are presented.", "author_names": [ "K Subramanian", "M Saraswathi", "P Poovarasan", "M P Uthra" ], "corpus_id": 44227746, "doc_id": "44227746", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Simulation study of nine level inverter fed 1 O induction motor drive", "venue": "2013 International Conference on Renewable Energy and Sustainable Energy (ICRESE)", "year": 2013 }, { "abstract": "3 Abstract: Random pulse width modulation (RPWM) in industrial drives is triumph in transferring of harmonic power from the detached spectrum of the output voltage to the unremitting spectrum and offers the merits viz. the operation free from an unpleasant acoustic noise and a mechanical vibration. The prime objective of this paper is providing a comprehensive investigation of performance of random pulse position pulse width modulation (RPPPWM) in a three phase voltage source inverter (VSI) fed induction motor drive through simulation and laboratory testing. RPPWM scheme randomly varies the pulse position in every switching cycle, where the idea is inducing the random characteristics in the PWM pulses at fixed switching frequency. The competence in spreading the harmonic power of sinusoidal PWM (SPWM) random carrier PWM (RCPWM) and the RPPWM are compared using simulation. The results are corroborated through the prototype VSI designed. The developed RPPPWM based on a SPARTAN 6 FPGA (XC6SLX45) device, disperses the acoustic switching noise spectra of an induction motor drive.", "author_names": [ "T Jarin", "P Subburaj" ], "corpus_id": 11401053, "doc_id": "11401053", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Performance Evaluation and Experimental Validation of Random Pulse Position Pwm for Industrial Drives", "venue": "", "year": 2015 }, { "abstract": "In industrial drives, random pulse width modulation (RPWM) is triumph for transferring of harmonic power from the detached spectrum of the output voltage to the unremitting spectrum, and offers the merits viz. The operation is free from an unpleasant acoustic noise and a mechanical vibration. The main objective of this paper is providing a comprehensive investigation of performance of random pulse position pulse width modulation (RPPPWM) for a three phase voltage source inverter (VSI) fed induction motor drives. RPPWM scheme randomly varies the pulse position in every switching cycle, where the idea is inducing the random characteristics in the PWM pulses at fixed switching frequency. The competence in spreading the harmonic power of sinusoidal PWM (SPWM) random carrier PWM (RCPWM) and the RPPWM are compared using simulation. The results are corroborated through the prototype VSI designed. The developed RPPPWM based on a SPARTAN 6 FPGA (XC6SLX45) device, disperses the acoustic switching noise spectra of an induction motor drive Full Text: PDF", "author_names": [ "P V Arulkumar", "N P Subramaniam" ], "corpus_id": 114190634, "doc_id": "114190634", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Experimental Evaluation and Validation of Random Pulse Position Pulse Width Modulation for Industrial Drives", "venue": "", "year": 2015 } ]
semiconductor deep learning
[ { "abstract": "Manual classification of particle defects on semiconductor wafers is labor intensive, which leads to slow solutions and longer learning curves on product failures while being prone to human error. This work explores the promise of deep learning for the classification of the chemical composition of these defects to reduce analysis time and inconsistencies due to human error, which in turn can result in systematic root cause analysis for sources of semiconductor defects. We investigate a deep convolutional neural network (CNN) for defect classification based on a combination of scanning electron microscopy (SEM) images and energy dispersive x ray (EDX) spectroscopy data. SEM images of sections of semiconductor wafers that contain particle defects are fed into a CNN in which the defects' EDX spectroscopy data is merged directly with the CNN's fully connected layer. The proposed CNN classifies the chemical composition of semiconductor wafer particle defects with an industrially pragmatic accuracy. We also demonstrate that merging spectral data with the CNN's fully connected layer significantly improves classification performance over CNNs that only take either SEM image data or EDX spectral data as an input. The impact of training data collection and augmentation on CNN performance is explored and the promise of transfer learning for improving training speed and testing accuracy is investigated.", "author_names": [ "Jared O'Leary", "Kapil U Sawlani", "Ali Mesbah" ], "corpus_id": 209517336, "doc_id": "209517336", "n_citations": 8, "n_key_citations": 1, "score": 1, "title": "Deep Learning for Classification of the Chemical Composition of Particle Defects on Semiconductor Wafers", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2020 }, { "abstract": "Quality inspection in semiconductor manufacturing is of great importance in the modern industries. In the recent years, intelligent data driven condition monitoring methods have been successfully developed and applied in the industrial applications. However, despite the promising condition monitoring performance, the existing methods generally assume the training and testing data are from the same distribution. In practice, due to variations in manufacturing process, the collected data are usually subject to different distributions in different operating conditions, that significantly deteriorates the performance of the data driven methods. To address this issue, this paper proposes a deep learning based domain adaptation method for fault diagnosis in semiconductor manufacturing. The maximum mean discrepancy metric is optimized on the learned high level data representation in the deep neural network. Experimental results on a real world semiconductor manufacturing dataset suggest the proposed method offers an effective and generalized data driven fault diagnosis approach for quality inspection.", "author_names": [ "Moslem Azamfar", "Xiang Li", "Jay Lee" ], "corpus_id": 219476558, "doc_id": "219476558", "n_citations": 7, "n_key_citations": 1, "score": 1, "title": "Deep Learning Based Domain Adaptation Method for Fault Diagnosis in Semiconductor Manufacturing", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2020 }, { "abstract": "Abstract An essential concept in technology management is the early detection of valuable patents. Traditional classification approaches have been utilized to identify effective patents based on the extracted patent topics and indices. However, they cannot consider detailed contextual information or relatively long word sequences in patent documents. In this study, we propose a patent grade evaluation framework based on a deep learning model that can capture the detailed semantic features of patent text. Therefore, this study adopts both a convolution neural network and bidirectional long short term memory with structured patent text data consisting of abstracts and claims for the classification of three levels of patent grades measured in terms of the average number of forward citations per annum. We further exploit the patent indices identified in the early stage as additional inputs to the model to increase the accuracy. Our model has realized over 75% precision and recall in identifying top grade semiconductor patents granted by the USPTO from 2000 to 2015. We anticipate that our deep learning based framework with patent text and indices will play a significant supporting role in mergers and acquisitions, investment decisions, and corporate planning through the early stage evaluation of a large number of patents.", "author_names": [ "Park Chung", "So Young Sohn" ], "corpus_id": 225253208, "doc_id": "225253208", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Early detection of valuable patents using a deep learning model: Case of semiconductor industry", "venue": "", "year": 2020 }, { "abstract": "A deep learning artificial neural network (NN) combined with the particle swarm optimization (PSO) method has been proposed to inversely design the semiconductor laser with high accuracy and computational speed. This method is exempt from the single solution problem of tandem NN and can be highly useful to extract the possible problematic parameters in the failure analysis of a device. The light current curves and small signal responses have been tested against the benchmarks calculated by the traveling wave model to demonstrate the NN's robustness and efficiency in simulating the laser behavior for further use in the inverse design by PSO.", "author_names": [ "Zi-Yan Ma", "Yu Li" ], "corpus_id": 220977001, "doc_id": "220977001", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Parameter extraction and inverse design of semiconductor lasers based on the deep learning and particle swarm optimization method.", "venue": "Optics express", "year": 2020 }, { "abstract": "Feature length extraction in cross sectional SEM (Scanning Electron Microscope) images of modern semiconductor devices is time consuming and laborious task. In this work, for the first time, automated measurement tool based on deep learning (DL) technology was developed; object detection model for determination of coordinate of each unit pattern and semantic segmentation model for obtaining the coordinate of boundary of each region (mask, substrate, and background) By combining results of these two models, typical features such as width and depth etc. are precisely and immediately extracted. We applied this tool to sample trench patterns and realized two orders faster extraction speed than manual operation.", "author_names": [ "Yutaka Okuyama", "Takeshi Ohmori" ], "corpus_id": 225388810, "doc_id": "225388810", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Deep Learning based Automated Measurement Method for Cross sectional SEM Images in Semiconductor Devices", "venue": "Microscopy and Microanalysis", "year": 2020 }, { "abstract": "Abstract. Defects in semiconductor processes can limit yield, increase overall production cost, and also lead to time dependent critical component failures. Current state of the art optical and electron beam (EB) inspection systems rely on rule based techniques for defect detection and classification, which are usually rigid in their comparative processes. This rigidity limits overall capability and increases relative engineering time to classify nuisance defects. This is further challenged due to shrinkage of pattern dimensions for advanced nodes. We propose a deep learning based workflow that circumvents these challenges and enables accurate defect detection, classification, and localization in a unified framework. In particular, we train convolutional neural network based models using high resolution EB images of wafers patterned with various types of intentional defects and achieve robust defect detection and classification performance. Furthermore, we generate class activation maps to demonstrate defect localization capability of the model \"without\" explicitly training it with defect location information. To understand the underlying decision making process of these deep models, we analyze the learned filters in pixel space and Fourier space and interpret the various operations at different layers. We achieve high sensitivity (97% and specificity (100% along with rapid and accurate defect localization. We also test performance of the proposed workflow on images from two distinct patterns and find that in order to retain high accuracy a modest level of retraining is necessary.", "author_names": [ "Dhruv V Patel", "Ravi Bonam", "Assad A Oberai" ], "corpus_id": 219077041, "doc_id": "219077041", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Deep learning based detection, classification, and localization of defects in semiconductor processes", "venue": "", "year": 2020 }, { "abstract": "Recently, the transportation capability of the automated material handling system (AMHS) has emerged as a major barrier to the semiconductor fabrication facility (FAB) because it can limit the FAB production capacity. In this study, we propose a prediction method for a machine allocation problem of production scheduling in consideration with the AMHS's constraints. The proposed method dynamically targets a machine for the next process by identifying diverse production conditions. We use a deep neural network based dynamic scheduling method considering the overall production environment, which includes the remaining processing time, facility states, transportation time and traffic congestion, work in process distribution, and intermediate buffer states. To demonstrate the superiority and efficiency of the proposed method, we conducted experimental studies to compare the proposed model with the existing priority rule based and analytic models under the static and dynamic environments. From the results, we verify that the proposed dynamic scheduling system can enhance the performance of existing AMHS and reduce machine starvation and production losses.", "author_names": [ "Haejoong Kim", "Dae-Eun Lim", "Sangmin Lee" ], "corpus_id": 211056605, "doc_id": "211056605", "n_citations": 8, "n_key_citations": 2, "score": 0, "title": "Deep Learning Based Dynamic Scheduling for Semiconductor Manufacturing With High Uncertainty of Automated Material Handling System Capability", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2020 }, { "abstract": "This thesis presents some methodological and experimental contributions to a deep learning based approach for the automatic classification of microscopic defects in silicon wafers with context information. Canonical image classification approaches have the limitation of utilizing only the information contained in the images. This work overcomes this limitation by using some context information about the defects to improve the current automatic classification system.", "author_names": [ "Simone Arena" ], "corpus_id": 225990311, "doc_id": "225990311", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A deep learning based approach for defect classification with context information in semiconductor manufacturing", "venue": "", "year": 2020 }, { "abstract": "In this paper, we present a system for the detection and classification of defects in semiconductor units. The proposed system consists of three stages: proposal generation stage, defect detection stage and refinement stage. In the proposal generation stage, changes on the target unit are detected using a novel change detection approach. In the second stage, a deep neural network is used to classify detected regions into either defective or non defective regions. Non defective regions are regions exhibiting allowable changes due to factors such as lighting conditions and subtle differences in manufacturing. The defect detection stage achieves up to 94.3% accuracy. In practice, defects that are smaller than a specified tolerance size are ignored by manufacturers. The tolerance size depends on the defect types and is determined based on risk factors. In order to ignore such defects, our approach includes a final refinement stage wherein the detected defects are categorized by a stacking based ensemble classifier into different classes. The refined system achieves up to 97.88% overall detection accuracy. The presented system is immediately applicable to different types of defects on die, epoxy and substrate. Inputs of the system can be either color or grayscale images.", "author_names": [ "Bashar M Haddad", "Samuel F Dodge", "Lina Karam", "Nital S Patel", "Martin W Braun" ], "corpus_id": 219956986, "doc_id": "219956986", "n_citations": 2, "n_key_citations": 1, "score": 0, "title": "Locally Adaptive Statistical Background Modeling With Deep Learning Based False Positive Rejection for Defect Detection in Semiconductor Units", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2020 }, { "abstract": "Due to advances in semiconductor processing technologies, each slice of a semiconductor is becoming denser and more complex, which can increase the number of surface defects. These defects should be caught early and correctly classified in order help identify the causes of these defects in the process and eventually help to improve the yield. In today's semiconductor industry, visible surface defects are still being inspected manually, which may result in erroneous classification when the inspectors become tired or lose objectivity. This paper presents a vision based machine learning based method to classify visible surface defects on semiconductor wafers. The proposed method uses deep learning convolutional neural networks to identify and classify four types of surface defects: center, local, random, and scrape. Experiments were performed to determine its accuracy. The experimental results showed that this method alone, without additional refinement, could reach a top accuracy in the range of 98% to 99% Its performance in wafer defect classification shows superior performance compared to other machine learning methods investigated in the experiments.", "author_names": [ "Jong-Chih Chien", "Mingtao Wu", "Jiann-Der Lee" ], "corpus_id": 225505909, "doc_id": "225505909", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Inspection and Classification of Semiconductor Wafer Surface Defects Using CNN Deep Learning Networks", "venue": "", "year": 2020 } ]
Sci. Adv. 2017，3，e1602246
[ { "abstract": "The rapid development of globalization and industrialization has caused a series of environment problems due to the increased consumption of fossil energy sources. To address these concerns, water splitting for hydrogen production in the presence of a semiconductor photocatalyst is studied extensively as a potential method to provide clean and renewable hydrogen source. In article 1600152, Yuekun Lai and co workers review various methods to construct 1D TiO2 nanotubes, and modified strategies to enhance solar light harvesting and energy conversion efficiency. Furthermore, the mechanism and applications of photo/photoelectro catalytic water splitting are comprehensively discussed.", "author_names": [ "Mingzheng Ge", "Qingsong Li", "Chunyan Cao", "Jianying Huang", "Shuhui Li", "Songnan Zhang", "Zhong Chen", "Ke-Qin Zhang", "Salem Slayyem Al-Deyab", "Yuekun Lai" ], "corpus_id": 40944845, "doc_id": "40944845", "n_citations": 6, "n_key_citations": 0, "score": 1, "title": "Water Splitting: One dimensional TiO2 Nanotube Photocatalysts for Solar Water Splitting (Adv. Sci. 1/2017)", "venue": "Advanced Science", "year": 2017 }, { "abstract": "Wenting Wu, Jianzhang Zhao and co workers present a summary of various controllable photodynamic therapy strategies based on switching the singlet oxygen on off process in article number 1700113. At the same time, the action mechanisms of different controllable PDT strategies, such as photoinduced electron transfer, fluorescence resonance energy transfer, intramolecular charge transfer and some physical/chemical means, are described carefully.", "author_names": [ "Wenting Wu", "Xiaodong Shao", "Jianzhang Zhao", "Mingbo Wu" ], "corpus_id": 7516582, "doc_id": "7516582", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Photodynamic Therapy: Controllable Photodynamic Therapy Implemented by Regulating Singlet Oxygen Efficiency (Adv. Sci. 7/2017)", "venue": "Advanced Science", "year": 2017 }, { "abstract": "In article number 1600362, Lothar Wondraczek and co workers present glass glass fluidic devices for large area integration with adaptive facades and smart windows, enabling harnessing and dedicated control of liquids for added functionality in the building envelope by wrapping buildings into a fluidic layer.", "author_names": [ "Benjamin P V Heiz", "Zhiwen Pan", "Gerhard Lautenschlager", "Christin Sirtl", "Matthias Kraus", "Lothar Wondraczek" ], "corpus_id": 37259876, "doc_id": "37259876", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Smart Windows: Ultrathin Fluidic Laminates for Large Area Facade Integration and Smart Windows (Adv. Sci. 3/2017)", "venue": "Advanced Science", "year": 2017 }, { "abstract": "In article number 1600274, Calderon Dominguez and co workers describe a new methodological approach to study bioenergetics in brown adipose tissue explants. It provides a more realistic comprehension of the tissue metabolism compared to previous cell based methods, with potential applications in basic science and antiobesity drug testing. The cover image represents the fuel burning potential of mitochondria within the brown adipose tissue.", "author_names": [ "Maria Calderon-Dominguez*", "Martin Alcala", "David Sebastian", "Antonio Zorzano", "Marta Viana", "Dolors Serra", "Laura Herrero" ], "corpus_id": 34456704, "doc_id": "34456704", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Bioenergetics: Brown Adipose Tissue Bioenergetics: A New Methodological Approach (Adv. Sci. 4/2017)", "venue": "Advanced Science", "year": 2017 }, { "abstract": "In article number 1700261, the Wu group presents poly(3,4 ethylenedioxythiophene) nanotubes (PEDOT NTs) conformally coated with porphyrin based metal organic framework nanocrystals (MOF 525) where MOF 525 serve as an electrocatalytic surface and PEDOT NTs act as a charge collector to rapidly transport the electron from MOF nanocrystals. The innovative composites establish a new generation of porous electrodes for highly efficient electrochemical biosensing.", "author_names": [ "Tzu-Yen Huang", "Chung-Wei Kung", "Yu-Te Liao", "Sheng-Yuan Kao", "Mingshan Cheng", "Ting-Hsiang Chang", "Joel Henzie", "Hatem R Alamri", "Zeid A Alothman", "Yusuke Yamauchi", "Kuo-Chuan Ho", "Kevin C-W Wu" ], "corpus_id": 39237674, "doc_id": "39237674", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Biosensing: Enhanced Charge Collection in MOF 525 PEDOT Nanotube Composites Enable Highly Sensitive Biosensing (Adv. Sci. 11/2017)", "venue": "Advanced Science", "year": 2017 }, { "abstract": "Open Access and Copyright: All articles published by Advanced Science are fully open access: immediately freely available to read, download and share. All articles are published under the terms of the Creative Commons Attribution License (CC BY) The CC BY license permits use, distribution and reproduction in any medium, provided the original work is properly cited and allows the commercial use of published articles. Covers and Editorials are published under the Creative Commons Attribution NonCommercial License (CC BY NC)", "author_names": [ "Kirsten Severing", "Lucie Kalvodova", "Hakim Meskine", "Adrian Miller", "Andrew Moore", "Ulf Scheffler", "Lorna Stimson", "Guangchen Xu", "Esther Levy", "Peter Gregory", "Petra Pinto", "Christine Herth", "Sonja Hoffmann", "Melanie Baumann" ], "corpus_id": 46671798, "doc_id": "46671798", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Masthead: (Adv. Sci. 6/2017)", "venue": "Advanced Science", "year": 2017 }, { "abstract": "On demand, ultra high precision delivery of molecules and cells is of great importance in the field of controlled release. In article number 1600410, inspired by sea sponges, Lei Yang, Yuekun Lai, and co workers design and fabricate a biomimetic macroporous ceramic composite sponge which reveals unique precise AND logic release behaviors of molecules and cells in response to dual gates of moisture and pressure (or strain)", "author_names": [ "Changlu Xu", "Zhihao Wei", "Huajian Gao", "Yanjie Bai", "Huiling Liu", "Huilin Yang", "Yuekun Lai", "Lei Yang" ], "corpus_id": 26267228, "doc_id": "26267228", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Drug Delivery: Bioinspired Mechano Sensitive Macroporous Ceramic Sponge for Logical Drug and Cell Delivery (Adv. Sci. 6/2017)", "venue": "Advanced Science", "year": 2017 }, { "abstract": "Open Access and Copyright: All articles published by Advanced Science are fully open access: immediately freely available to read, download and share. All articles are published under the terms of the Creative Commons Attribution License (CC BY) The CC BY license permits use, distribution and reproduction in any medium, provided the original work is properly cited and allows the commercial use of published articles. Covers and Editorials are published under the Creative Commons Attribution NonCommercial License (CC BY NC)", "author_names": [ "Kirsten Severing", "Lucie Kalvodova", "Hakim Meskine", "Adrian Miller", "Andrew Moore", "Ulf Scheffler", "Lorna Stimson", "Guangchen Xu", "Esther Levy", "Peter Gregory", "Petra Pinto", "Christine Herth", "Sonja Hoffmann", "Melanie Baumann" ], "corpus_id": 41714375, "doc_id": "41714375", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Masthead: (Adv. Sci. 5/2017)", "venue": "Advanced Science", "year": 2017 }, { "abstract": "In article number 1700159, Eugen Rabkin and co workers observe the self healing and shape memory effects in single crystalline faceted gold particles of sub micrometer dimensions. Particles indented with a sharp diamond tip restored their original asymmetric shape after annealing at 600 degC. Atomistic and mesoscopic models demonstrate how a combination of plastic deformation and diffusion, which are classical examples of irreversible processes, can lead to a reversible shape recovery of the deformed particles.", "author_names": [ "Oleg Kovalenko", "Christian Brandl", "Leonid Klinger", "Eugen Rabkin" ], "corpus_id": 13242913, "doc_id": "13242913", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Shape Memory: Self Healing and Shape Memory Effects in Gold Microparticles through the Defects Mediated Diffusion (Adv. Sci. 8/2017)", "venue": "Advanced Science", "year": 2017 }, { "abstract": "Open Access and Copyright: All articles published by Advanced Science are fully open access: immediately freely available to read, download and share. All articles are published under the terms of the Creative Commons Attribution License (CC BY) The CC BY license permits use, distribution and reproduction in any medium, provided the original work is properly cited and allows the commercial use of published articles. Covers and Editorials are published under the Creative Commons Attribution NonCommercial License (CC BY NC)", "author_names": [ "Kirsten Severing", "Prisca Henheik", "Anne Pfisterer", "Duoduo Liang", "Matt Lock", "Anke Osterland", "Lucie Kalvodova", "Ester Levy", "Peter Gregory", "Hakim Meskine", "Andrew Moore", "Lorna Stimson", "Guangchen Xu", "Petra Pinto", "Christine Herth", "Sonja Kwiatkowskyj", "Melanie Baumann" ], "corpus_id": 13345996, "doc_id": "13345996", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Masthead: (Adv. Sci. 11/2017)", "venue": "Advanced Science", "year": 2017 } ]
measurement of powder wettability
[ { "abstract": "Abstract In the present work, size tunable ZnS scotch tape nanocomposite materials were successfully prepared using SILAR method. Scanning electron microscopy (SEM) Atomic Force Microscopy (AFM) X ray powder diffraction (XRD) and Brunauer Emmett Teller (BET) porosity measuring techniques were used for morphological, structural and porosity determination of the prepared nanocomposite materials. UV Visible absorption and Fourier Transform infrared (FTIR) spectroscopy techniques were used for investigation of optical properties of the prepared nanocomposite. The confinement of electrons and holes in semiconductor nanostructured materials in lower cycles of SILAR depicts a blue shift in the band gap, which obtained by UV Visible absorption spectra and described by Effective Mass Approximation (EMA) and Hyperbolic Band Model (HBM) In higher cycles of SILAR, with increasing in particles sizes, a red shift was observed at the position of the peak in the absorption spectrum and consequently optical band gap decreases. Wettability measurement of ZnS scotch tape nanocomposite materials was investigated by contact angle measurement of water drop on the surface. BET results show a various and alternative behavior. At initial cycles of SILAR, the special surfaces are decreases by increasing cycles of SILAR until 4 cycles, then after 4 cycles of SILAR, the special surfaces are increased with increasing cycles of SILAR, until 12 cycles, then, the special surfaces have decreased with increasing cycles until 16 cycles of SILAR.", "author_names": [ "Javid Farazin", "Gholamreza Pirgholi-Givi", "Yashar Azizian-Kalandaragh" ], "corpus_id": 132475357, "doc_id": "132475357", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Wettability measurement, optical characteristics, and investigation of the quantum confinement effect of ZnS scotch tape nanocomposite films prepared by successive ionic layer adsorption and reaction (SILAR) method", "venue": "Physica B: Condensed Matter", "year": 2019 }, { "abstract": "Abstract Washburn Method (WM) as a typical contact angle measurement (th) method can be used for assessment of powder wettability (especially representative particle size range for flotation separation) However, as an indirect method, WM has several limitations. This investigation is going to introduce an Enhanced Washburn Method (EWM) which fills the gap of those WM obstacles, and can be applied for the meaningful indirect th measurement of powders. For such a purpose, the wettability of quartz powders (d80: 62 mm) was measured in the absence and in the presence of the cationic surfactant Flotigam(r)EDA at pH 10. EWM by using pre conditioning of hydrophobized particles via unblock capillaries measured the th of powders in different conditions. Statistical evaluations indicated that EWM could quite accurately measure th of the hydrophobized powders, where there is a significant coefficient of determination (R2 above 0.96) between EWM outcomes and other examined direct th measurement methods (the captive bubble and sessile drop methods)", "author_names": [ "Arash Tohry", "R Atash Dehghan", "Alexandre Vale Oliveira", "Saeed Chehreh Chelgani", "Laurindo de Salles Leal Filho" ], "corpus_id": 229509022, "doc_id": "229509022", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Enhanced Washburn Method (EWM) A comparative study for the contact angle measurement of powders", "venue": "", "year": 2020 }, { "abstract": "Abstract Based on the work initiated by Shanker, R.M. Baltusis, P.J. and Hruska, R.M. (Development of a new technique for the assessment of wettability of powders. Pharm. Res. 11 (Suppl) (1995) s243 (abstract) and Dove, J.W. Buckton, G. and Doherty, C. (Comparison of wetting behaviour of theophylline and caffeine using various contact angle measurement methods and inverse gas chromatography. In 15th Pharm. Technol. Conf. 19 21 March 1996, Oxford, UK) this study has focused on the determination of effectively wet perimeters during Wilhelmy plate immersion experiments of powder stuck on glue. Data generated from extrapolated immersion loads of plates in two different apolar liquids, enable a measure of powder wet perimeter. Such perimeters are used to derive contact angles of reference liquids on the particular powder. Two powders were taken as models: starch and ketoprofen.", "author_names": [ "Xavier J H Pepin", "Sylvene Blanchon", "Guy Couarraze" ], "corpus_id": 98045880, "doc_id": "98045880", "n_citations": 20, "n_key_citations": 0, "score": 1, "title": "A new approach for determination of powder wettability", "venue": "", "year": 1997 }, { "abstract": "Abstract Super hydrophobic carbon nanotube (CNT) powders were formed by NF 3 glow discharge plasma at low pressure and their surface free energies were directly determined from the contact angles with probe liquids using the Owens Wendt plotting. The cushion made of plasma treated CNT powders revealed super hydrophobicity (contact angle 153deg) regardless of kinds of probe liquids and treatment time. The surface free energy of the NF 3 plasma treated CNT powders decreased drastically from 82.6 to 0.12 mJ/m 2 The plasma treatment using fluorinated compound gases may be useful for dispersing, separating, and cutting CNTs since CNTs have tendency to aggregate in bundles and poor solubility.", "author_names": [ "Yong Cheol Hong", "Dong Hun Shin", "Soon Cheon Cho", "Han Sup Uhm" ], "corpus_id": 97950913, "doc_id": "97950913", "n_citations": 44, "n_key_citations": 1, "score": 0, "title": "Surface transformation of carbon nanotube powder into super hydrophobic and measurement of wettability", "venue": "", "year": 2006 }, { "abstract": "In this work a cost effective instrument for measuring the wettability of powder materials was designed and developed, which works on the modified Washburn method. The instrument measures the mass gain against time due to penetration of the liquid into the powder materials using a microbalance and LabVIEW based data acquisition system. The wettability characteristic of different powders was determined from the contact angle using the modified Washburn equation. To demonstrate the performance of the developed instrument, the wettability of as received corn starch and nano coated corn starch powders was estimated with water as a test liquid. The corn starch powders coated with hydrophilic grade (Aerosil 200P) and hydrophobic grade (Aerosil R972) nanoparticles at different coating levels showed expected changes in their contact angle. Some of the results were also verified against the available standard instrument for wettability measurement and found to be consistent. The present configuration of the instrument costs about 500 US$ which is 15 to 20 times less than the available advanced models. The developed instrument is thus a cost effective solution for wettability measurement which can be used for materials in food processing, pharmaceuticals, horticulture, textile manufacturing, civil engineering etc. The developed instrument is expected to help many small scale industries or research labs who cannot afford an expensive instrument for wettability studies.", "author_names": [ "Manish T Thakker", "Vikram Karde", "Dinesh O Shah", "Premal R Shukla", "Chinmay Ghoroi" ], "corpus_id": 121629854, "doc_id": "121629854", "n_citations": 19, "n_key_citations": 0, "score": 0, "title": "Wettability measurement apparatus for porous material using the modified Washburn method", "venue": "", "year": 2013 }, { "abstract": "Equipment for measuring the wettability (i. e. the contact angle) of hydrophobic powder was newly developed, based upon the so called constant flow method. This equipment has a feature in which the specific surface area of the powder, the threshold pressure at which a liquid begins to penetrate the powder bed and its contact angle are calculated and printed out. This happens when the values related to the operational conditions and the physical properties of air, liquid and powder used in the measurement are put in advance into the computer installed in this equipment.The availability of this equipment was confirmed by investigating the effect of operational factors such as the feed rate of pure water, the porosity of the powder bed and its height on the contact angle of aluminum hydroxide powder treated with stearic acid. The relationship between the contact angle of the sample powder and the concentration of stearic acid, the mixing time, the dispersion state in pure water or the amount of DOP (dioctyl phthalate) absorbed was also obtained.", "author_names": [ "Kanji Matsumoto", "Hideaki Akutsu", "Akihiko Yoshimidzu", "Gong-hong Hong", "Kinnosuke Watanabe" ], "corpus_id": 102008686, "doc_id": "102008686", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "The Measurement of the Wettability of Hydrophobic Powder by the Constant flow Method", "venue": "", "year": 1988 }, { "abstract": "&NA; The aim of this study was to evaluate the choice of polymer and polymer level on the performance of the microstructure and wettability of hot melt extruded solid dispersion of Glyburide (Gly) as a model drug. The produced solid dispersion were characterised using scanning electron microscopy (SEM) image analysis using a focus variation instrument (FVI) differential scanning calorimetry (DSC) X ray powder diffraction (XRPD) X ray microtomography (X&mgr;T) dynamic contact angle measurement and dissolution analysis using biorelevant dissolution media (FASSIF) SEM and focus variation analysis showed that the microstructure and surface morphology was significantly different between samples produced. This was confirmed by further analysis using X&mgr;T which showed that an increase in polymer content brought about a decrease in the porosity of the hot melt extruded dispersions. DSC suggested complete amorphorisation of Gly whereas XRPD suggested incomplete amorphorisation. The static and dynamic contact angle measurement correlated with the dissolution studies using FASSIF media indicating that the initial liquid imbibition process as captured by the dynamic contact angle directly affects the dissolution performance. Graphical abstract Figure. No caption available. HighlightsSolid dispersions of glyburide made by hot melt extrusion.SEM and focus variation showed microstructure and surface morphology was significantly different.X&mgr;T showed that an increase in polymer content brought about a decrease in porosity.Static and dynamic contact angle correlated with dissolution using FASSIF media.Liquid imbibition captured by dynamic contact angle affects dissolution performance.", "author_names": [ "Maen Alshafiee", "Mohammad K Aljammal", "Daniel Markl", "Adam Ward", "Karl Walton", "Liam Blunt", "Sachin Korde", "Sudhir K Pagire", "Adrian L Kelly", "Anant Paradkar", "Barbara R Conway", "Kofi Asare-Addo" ], "corpus_id": 73412242, "doc_id": "73412242", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Hot melt extrusion process impact on polymer choice of glyburide solid dispersions: The effect of wettability and dissolution", "venue": "International journal of pharmaceutics", "year": 2019 }, { "abstract": "Abstract Coal wettability is of considerable importance for determining the efficiency of the solubilization process. In principle, hydrophobic coal structure should be modified for effective contact with microorganisms in the coal biosolubilization process. The paper considers the image analysis method for determining the contact angle of chemically pretreated coal, where the measurement surface is prepared by pressing coal powder into tablets. Due to sessile drop asymmetry resulting from the heterogeneity of the substrate, liquid solid contact angles are evaluated along a three phase contact line. The source of a three dimensional drop image is a scan obtained with an infrared light beam from an optical coherence tomography device. The effect of coal pretreatment on biosolubilization by Gordonia alkanivorans S7 was investigated with the use of the method. To emphasize the relationship between coal wettability (hydrophilicity or hydrophobicity) and the possibility of coal liquefaction, Fourier Transform Infrared (FT IR) spectroscopic analyses were performed. Data obtained from infrared spectra showed changes in coal structure and confirmed a positive influence of nitric acid on coal biosolubilization. Due to a high liquefaction degree, it is possible to implement the process of lignite biosolubilization by G. alkanivorans S7 on a larger scale. The contact angle measurement method can be successfully applied in the selection of methods for the chemical and biological conversion of coal in various technological processes.", "author_names": [ "Jaroslaw Goclawski", "Joanna Sekulska-Nalewajko", "Bartosz Strzelecki", "Irena Romanowska" ], "corpus_id": 202080598, "doc_id": "202080598", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Wettability analysis method for assessing the effect of chemical pretreatment on brown coal biosolubilization by Gordonia alkanivorans S7", "venue": "Fuel", "year": 2019 }, { "abstract": "The Wilhelmy method of the contact angle measurement was used for the wettability study of Fe2O3 and TiO2 pigments in aqueous environment. The pigment samples were attached to a glass plate by means of an adhesive layer. This simple technique allows relatively quick quantitative evaluations of powder samples' wettabilities avoiding problems accompanying the preparation of the sample by pressing necessary for sessile drop or Washburn method measurements.", "author_names": [ "Libor Kvitek", "Petr Pikal" ], "corpus_id": 18022288, "doc_id": "18022288", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "THE STUDY OF THE WETTABILITY OF POWDER INORGANIC PIGMENTS BASED ON DYNAMIC CONTACT ANGLE MEASUREMENTS USING WILHELMY METHOD", "venue": "", "year": 2002 }, { "abstract": "A simple experimental apparatus, based on the washburn equation, has been designed to evaluate the wettability of powder by measurement of the permeating height The concept of relative wetting contact angle (RWCA) has been put forward, and values of four kinds of ultra fine ZrO 2 powder have been measured", "author_names": [ "Ai De" ], "corpus_id": 101629204, "doc_id": "101629204", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "MEASUREMENT OF WETTING CONTACT ANGLE OF POWDER BY PERMEATING HEIGHT METHOD", "venue": "", "year": 2001 } ]
Monolayer assessment MD aimulation
[ { "abstract": "After an initial assessment of the structural and electronic properties of graphene, monolayer MoS2, and graphene/MoS2 bilayer hetero structure, the temperature dependent thermodynamic properties of graphene/MoS2 bilayer hetero structure are examined by using density functional theory calculations. The structure, bandgap, partial density of states, and thermodynamic properties of graphene, monolayer MoS2 and graphene/MoS2 system are investigated and analyzed. Findings from the present study are in good agreement with the previously reported theoretical and experimental studies. Monolayer MoS2 and graphene form a stable Van der Waals heterostructure owing to their negative binding energy, and the system acts as a zero bandgap semiconductor. Debye temperature and the heat capacity of graphene, MoS2 monolayer, and graphene/MoS2 system are calculated from phonon dispersion relations to be 2100 K, 600 K, and 1400 K, and 0.7 J/g.K, 0.218 J/g.K, and 0.46 J/g.K, respectively. Introduction of graphene into the MoS2 semiconductor is, therefore, found to improve the overall thermodynamic properties of the composite as graphene preserved its superior thermal properties. The findings will be beneficial to calculate thermal conductivity of the graphene/MoS2 heterostructure for minimizing the temperature effect in electronic or optoelectronic devices.", "author_names": [ "Md Tanver Hossain", "Md Ashiqur Rahman" ], "corpus_id": 210985828, "doc_id": "210985828", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "A first principle study of the structural, electronic, and temperature dependent thermodynamic properties of graphene/MoS2 heterostructure", "venue": "Journal of Molecular Modeling", "year": 2020 }, { "abstract": "s for Journals and Proceedings Kaisani A, Delgado O, Kim S, Richardson JA, Wright WE, Story MD, Minna JD, Shay JW. \"Risk Assessment of Radiation Induced Invasive Cancer in Mouse Models of Lung Cancer.\" 23rd Annual NASA Space Radiation Investigators' Workshop, Durham, NC, July 8 11, 2012. Poster Presentation. 23rd Annual NASA Space Radiation Investigators' Workshop, Durham, NC, July 8 11, 2012. Jul 2012 Abstracts for Journals and Proceedings Asaithamby A, Chen DJ. \"Mechanism of HZE particles induced chromosome instability.\" 23rd Annual NASA Space Radiation Investigators' Workshop, Durham, NC, July 8 11, 2012. Oral Presentation. 23rd Annual NASA Space Radiation Investigators' Workshop, Durham, NC, July 8 11, 2012. Jul 2012s for Journals and Proceedings Asaithamby A, Chen DJ. \"Mechanism of HZE particles induced chromosome instability.\" 23rd Annual NASA Space Radiation Investigators' Workshop, Durham, NC, July 8 11, 2012. Oral Presentation. 23rd Annual NASA Space Radiation Investigators' Workshop, Durham, NC, July 8 11, 2012. Jul 2012 Abstracts for Journals and Proceedings Asaithamby A, Chen DJ. \"Biological consequences of unrepaired clustered DNA lesions in response to high atomic number and energy particles in monolayer and organotypic cell cultures.\" 39th Annual Meeting of the European Radiation Research Society, Vietri sul Mare, Italy, October 15 19, 2012. Oral Presentation. 39th Annual Meeting of the European Radiation Research Society, Vietri sul Mare, Italy, October 15 19, 2012. Abstract Book, p. 72. http:/www.iss.infn.it/ Oct 2012s for Journals and Proceedings Asaithamby A, Chen DJ. \"Biological consequences of unrepaired clustered DNA lesions in response to high atomic number and energy particles in monolayer and organotypic cell cultures.\" 39th Annual Meeting of the European Radiation Research Society, Vietri sul Mare, Italy, October 15 19, 2012. Oral Presentation. 39th Annual Meeting of the European Radiation Research Society, Vietri sul Mare, Italy, October 15 19, 2012. Abstract Book, p. 72. http:/www.iss.infn.it/ Oct 2012 Abstracts for Journals and Proceedings Asaithamby A, Chen DJ. \"Unrepaired clustered DNA lesions together with defective G2/M checkpoint induce chromosome instability in human cells.\" The 10th International Symposium on Chromosomal Aberrations, Amalfi, Italy, October 19 21, 2012. Oral Presentation. The 10th International Symposium on Chromosomal Aberrations, Amalfi, Italy, October 19 21, 2012. http:/www.iss.infn.it/ Oct 2012s for Journals and Proceedings Asaithamby A, Chen DJ. \"Unrepaired clustered DNA lesions together with defective G2/M checkpoint induce chromosome instability in human cells.\" The 10th International Symposium on Chromosomal Aberrations, Amalfi, Italy, October 19 21, 2012. Oral Presentation. The 10th International Symposium on Chromosomal Aberrations, Amalfi, Italy, October 19 21, 2012. http:/www.iss.infn.it/ Oct 2012 Abstracts for Journals and Proceedings Shay JW, Cucinotta FA, Sulzman FM, Coleman CN, Minna JD. \"From mice and men to Earth and space: joint NASA NCI workshop on lung cancer risk resulting from space and terrestrial radiation.\" 23rd Annual NASA Space Radiation Investigators' Workshop, Durham, NC, July 8 11, 2012. Oral presentation. 23rd Annual NASA Space Radiation Investigators' Workshop, Durham, NC, July 8 11, 2012. Jul 2012s for Journals and Proceedings Shay JW, Cucinotta FA, Sulzman FM, Coleman CN, Minna JD. \"From mice and men to Earth and space: joint NASA NCI workshop on lung cancer risk resulting from space and terrestrial radiation.\" 23rd Annual NASA Space Radiation Investigators' Workshop, Durham, NC, July 8 11, 2012. Oral presentation. 23rd Annual NASA Space Radiation Investigators' Workshop, Durham, NC, July 8 11, 2012. Jul 2012 Abstracts for Journals and Proceedings Minna JD, Story MD, Girard L, Delgado O, Asithamby A, Chen D, Park S, Larsen J, Das A, Gao B, Richardson J, Gazdar AF, Xie Y, Xie X J, Shay JW. \"Development of a risk assessment model for lung cancer pathogenesis after exposure of human and mouse lung epithelial cells to HZE particle radiation.\" 23rd Annual NASA Space Radiation Investigators' Workshop, Durham, NC, July 8 11, 2012. (Oral Presentation, NSCOR retreat) 23rd Annual NASA Space Radiation Investigators' Workshop, Durham, NC, July 8 11, 2012. Jul 2012s for Journals and Proceedings Minna JD, Story MD, Girard L, Delgado O, Asithamby A, Chen D, Park S, Larsen J, Das A, Gao B, Richardson J, Gazdar AF, Xie Y, Xie X J, Shay JW. \"Development of a risk assessment model for lung cancer pathogenesis after exposure of human and mouse lung epithelial cells to HZE particle radiation.\" 23rd Annual NASA Space Radiation Investigators' Workshop, Durham, NC, July 8 11, 2012. (Oral Presentation, NSCOR retreat) 23rd Annual NASA Space Radiation Investigators' Workshop, Durham, NC, July 8 11, 2012. Jul 2012 Abstracts for Journals and Proceedings Park S, Ding LH, Larsen JE, Minna JD, Story MD. \"Genomic characterization of transformed human bronchial epithelial cells induced by ionizing radiation.\" 23rd Annual NASA Space Radiation Investigators' Workshop, Durham, NC, July 8 11, 2012. Oral presentation. 23rd Annual NASA Space Radiation Investigators' Workshop, Durham, NC, July 8 11, 2012. Jul 2012s for Journals and Proceedings Park S, Ding LH, Larsen JE, Minna JD, Story MD. \"Genomic characterization of transformed human bronchial epithelial cells induced by ionizing radiation.\" 23rd Annual NASA Space Radiation Investigators' Workshop, Durham, NC, July 8 11, 2012. Oral presentation. 23rd Annual NASA Space Radiation Investigators' Workshop, Durham, NC, July 8 11, 2012. Jul 2012 Page 10 of 11 Task Book Report Generated on: 07/07/2020", "author_names": [ "Rolf A Brekken" ], "corpus_id": 202896272, "doc_id": "202896272", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "NSCOR: Risks Estimates and Mechanisms of Lung Cancer Pathogenesis after Space Radiation", "venue": "", "year": 2019 }, { "abstract": "Ischemia/reperfusion (I/R) injury is a broad area of medical significance, and includes gut ischemia consequent to such diverse causes as endurance sports activity and congestive heart failure. Few studies have focused on assessment of the direct effects of ischemia on intestinal epithelial integrity. Furthermore, clinical efforts at mitigating the effect of hypoperfusion on gut permeability have focused on restoring gut vascular function. Here we report that, in the Caco 2 cell model of transepithelial transport, calcium glycerophosphate (CGP) an inhibitor of intestinal alkaline phosphatase F3, has a significant effect to preserve transepithelial electrical resistance and to attenuate increases in mannitol flux rates during hypoxia or cytokine stimulation. The effect was observable even at concentrations as low as 1mM. As celiac disease is also marked by a loss of gut epithelial integrity, the effect of CGP to attenuate the effect of the gliadin peptide 31 55 was also examined. In this instance, CGP exerted little effect of preservation of TEER, but significantly attenuated peptide induced increase in mannitol flux. In conclusion, it appears that CGP treatment might synergise with other therapies to preserve gut epithelial integrity. Calcium glycerophosphate and intestinal epithelial permeability. Introduction: Ischemia/reperfusion (I/R) injury is a broad area of medical significance. Stroke and coronary artery disease (CAD) are the most obvious examples of I/R injury. However, the fundamental problem is much broader, and includes gut ischemia consequent to splanchnic hypoperfusion. Chronic gut ischemia is not so dramatic as stroke or CAD, but may be more insidious. Splanchnic hypoperfusion is a consequence of endurance sports activity [Peters et al. 1999; Van Wijck e al. 2012a] and a significant element in the pathophysiology of congestive heart failure [Sandek et al, 2010; Celik et al, 2010;Sandek et al, 2007; Kruger et al, 2007] shock [Arvidsson et al, 1991] cardiac surgery [Jakob, 2002] and hemodialysis [Jakob et al, 2001] Although the ultimate causes of hypoperfusion are different in each of these clinical situations, they share similar clinical consequences. During simulated gut ischemia, there is extensive neutrophil recruitment to the post capillary venule, a process that is dependent, at least in part, on long chain fatty acyl CoA synthetase [Blakeman et al. 2012; Prior et al, 2014] likely acting by inhibiting cell adhesion protein palmitoylation [Sardjono et al. 2006; Sim et al. 2007] The subsequent immune system activation increases synthesis of an array of cytokines, including TNF, IL and IFN. While these have been studied extensively in various pathologies involving splanchnic hypopoperfusion [Esposito et al. 2007; Cavriani et al. 2007] few studies have focused on assessment of the direct effects of either hypoxia or cytokine liberation on intestinal epithelial integrity [Xu et al. 1999; Qiu et al. 2014] Furthermore, clinical efforts at mitigating the effect of hypoperfusion on gut permeability have focused on restoring gut vascular function. Gut epithelial integrity is dependent, at least in part, on sphingosine 1 phosphate (S1P) generation [Greenspon et al. 2011] Earlier studies revealed that beta calcium glycerophosphate (CGP) is an inhibitor of intestinal F3 alkaline phosphatase [Tardivel et al. 1988] As alkaline phosphatase catalyzes the conversion of S1P to sphingosine and inorganic phosphate [Edsall and Spiegel, 1999] here we test the hypothesis that, by inhibiting intestinal alkaline phosphatase, CGP might raise the S1P concentrations, thus helping to preserve intestinal integrity during ischemic insult. Calcium glycerophosphate and intestinal epithelial permeability. Methods: All experiments were conducted on Caco 2 cells, a line of cells derived from a colorectal carcinoma, and obtained from American Type Culture Collection (Rockville MD) Upon prolonged culture, these cells express the characteristics of small intestinal enterocytes [Jumarie and Malo, 1991] They are widely used as a model of transepithelial transport in the small intestine, and are considered a model for celiac disease [Iacomino et al, 2013; Caputo et al, 2012; Rauhavirta et al, 2013] Cells were grown on a transwell inserts (6 well, 12 well or 24well, 0.4 micron pore size, PET Polyester, Corning) a permeable barrier system, in minimal essential media (MEM) supplemented with 20% fetal calf serum. Cells were seeded at a density of 3.9 X 10/cm, and media was changed at 2 day intervals. The media volumes in the apical and basolateral chambers were 1.5ml and 1 ml (6 well plates) 0.5 ml and 1 ml (12 well plates) and 0.1 ml and 0l5 ml (24 well plates) respectively. Measurement of transepithelial electrical resistance: The tightness of the tight junctions in a transporting epithelium was evaluated by measuring the transepithelial electrical resistance (TEER) TEER measures the movement of ions across the cell (transcellular) and between cells (paracellular) In a very tight monolayer, transport is nearly all transcellular, hence the electrical resistance is high; the electrical resistance across the membrane was measured using the EVOM2 epithelial voltohmmeter (World Precision Instruments, Sarasota FL, USA) At 3 to 4 weeks in culture, TEER was in the range of 600 700 /cm. Mannitol flux: The TEER results were complemented by measuring mannitol flux. Cells were seeded into 6 well plates, and [C] labeled mannitol (10 mM) was added to the apical media; 10ml samples were removed from the basolateral media at intervals throughout the experiment. The rate of mannitol flux was determined by calculating the slope of dpm in the basolateral chamber as a function of time. E cadherin expression: E cadherin is the principle protein of tight junctions. The levels of Ecadherin was measured in cells by western blot analysis (primary antibody from BD biosciences) Sphingosine 1 Phosphate: Calcium glycerophosphate has activity as a phosphatase inhibitor, inviting our hypothesis that CGP elevates S1P concentrations by inhibiting dephosphorylation. S1P concentrations were measured in the media of Caco 2 cells using a commercially available ELISA kit (Echelon Catalog K 1900) Baseline values of mannitol flux, TEER and S1P were obtained in unstimulated cells, in the presence and absence of increasing concentrations of CGP. The effect of hypoxia was measured for TEER and mannitol flux, in the presence and absence of CGP. Cells were grown to confluence on transwells, 0.4 micron pore size. Experiments in hypoxic conditions were conducted in a hypoxia chamber (Coy Laboratory Products, Grass Lake MI, USA) as detailed elsewhere [Yang et al. 2006] Briefly, confluent cultures were placed in the chamber under a 95% N2/5% CO2 atmosphere and fed with serum and glucose free MEM, and bubbled with 95% N2/5% CO2. Under these conditions, the PO2 in the media is below 25 mm Hg (6% Normoxic conditions were the standard CO2 incubator and media containing glucose. The effect of exogenous cytokines were measured for each parameter, in the presence and absence of CGP. Both hypoxia/ischemia and celiac disease are characterized by cytokine release, which increase monolayer permeability [5] A mixture of the cytokines TNF, ILand Calcium glycerophosphate and intestinal epithelial permeability. IF (final concentrations: 10 ng/ml; 1 ng/ml; 100 ng/ml, respectively) then TEER, mannitol flux, E Cadherin expression and media concentrations of S1P were measured. The effect of gliadin 31 55 peptide was measured for each parameter. Gliadin is the offending protein initiating the symptoms of celiac disease in susceptible patients. Gastric and pancreatic proteases cleave gliadin to peptides, which are likely the direct cause of the enteropathy. The literature [Iacomino et al, 2013] suggests that the peptide comprised of gliadin amino acids 31 55 is a likely candidate. The peptide (Thermo Scientific, Custom synthesis) and added to the media at 100mg/ml. Calcium glycerophosphate and intestinal epithelial permeability.", "author_names": [ "P Datta", "Margaret T Weis" ], "corpus_id": 201605911, "doc_id": "201605911", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "CALCIUM GLYCEROPHOSPHATE ATTENUATES HYPOXIA AND CYTOKINE INDUCED INCREASES IN EPITHELIAL PERMEABILITY IN THE CACO 2 MODEL OF INTESTINAL TRANSPORT", "venue": "", "year": 2019 }, { "abstract": "The secreted hexameric form of the dengue virus non structural protein 1 (NS1) has recently been shown to elicit inflammatory cytokine release and disrupt endothelial cell monolayer integrity. This suggests that circulating NS1 contributes to the vascular leak that plays a major role in the pathology of dengue haemorrhagic fever and shock. Pathways activated by NS1 are thus of great interest as potential therapeutic targets. Recent works have separately implicated both Toll like receptor 4 (TLR4) and the TLR2/6 heterodimer in immune cell activation by NS1. Here we have used mouse gene knockout macrophages and antibodies blocking TLR function in human peripheral blood mononuclear cells to show that recombinant NS1, expressed and purified from eukaryotic cells, induces cytokine production via TLR4 but not TLR2/6. Furthermore, the commercial E. coli derived recombinant NS1 preparation used in other work to implicate TLR2/6 in the response is not correctly folded and appears to be contaminated by several microbial TLR ligands. Thus TLR4 remains a therapeutic target for dengue virus infections, with TLR4 antagonists holding promise for the treatment of dengue disease. INTRODUCTION The dengue virus (DENV) NS1 protein functions intracellularly to promote viral replication, but is also secreted from infected mammalian cells as a 300 kDa hexameric glycoprotein. This hexameric species is found circulating in the blood of infected individuals and its presence is used for the rapid diagnosis of DENV infection. Recent results suggest a critical role for NS1 in the vascular leak that characterises severe infection. We demonstrated that NS1 activates both immune and endothelial cells via engagement with TLR4, leading to cytokine secretion and endothelial cell monolayer disruption. Furthermore, we found that TLR2 was not involved in the response to NS1. The best studied ligand for the TLR4/MD 2 complex is bacterial lipopolysaccharide (LPS) although a number of viral proteins including Ebola virus glycoprotein, respiratory syncytial virus F protein, and human immunodeficiency virus Tat protein, have also been shown to be TLR4 agonists. In contrast, Chen and colleagues reported that NS1 activates human and murine immune cells via TLR2 and TLR6, which otherwise act as a heterodimer in the recognition of diacylated lipoproteins from some Gram positive bacteria and Mycoplasma. To resolve these apparently contradictory reports on innate immune recognition of NS1, we assessed the roles of TLR2, TLR4 and TLR6 in response to the different sources of NS1 used in the two papers. RESULTS AND DISCUSSION Chen et al. used commercially available recombinant E. coli derived NS1 (Abcam Cat. 64456) in experiments implicating TLR2/6 in recognition of NS1. The Abcam product is Cterminally His tagged NS1 from DENV 1, supplied in 1.5 M urea and recommended for use in ELISA and western blot applications. We first compared the oligomeric state of E. coliderived NS1 to DENV 2 NS1 immunoaffinity purified from the supernatant of stablytransfected S2 cells \"insect NS1\" or from the medium of DENV 2 infected Vero cells cultured without serum \"native NS1\" The secreted form of NS1 has a barrel like hexameric structure formed by a trimer of stable NS1 dimers. The formation of this oligomeric structure is dependent on both glycosylation and correct disulphide bonding of the 12 cysteines in NS1. Immunoaffinity purified preparations of NS1 used routinely in our laboratory are hexameric, based on both size exclusion chromatography and electron microscopic (EM) analysis (Modhiran et al. Figure S1) Chemical cross linking confirms the hexameric nature of the particles seen on EM. Insect cell expressed NS1 hexamers dissociate to dimers upon SDS PAGE analysis of unboiled samples, and to monomers after boiling, regardless of the presence or absence of reducing agent (Figure 1) In contrast, the commercially available E. coli derived NS1 was monomeric under all conditions, with an unknown low molecular weight product also noted. Thus the E. coli derived NS1 is not in its native conformation and is likely denatured given that it is supplied in 1.5 M urea. Such a misfolded protein may be suitable as an antigen substrate for western blot and qualitative ELISA analyses using antibodies recognising linear epitopes, but are less likely to be functional in receptor activation studies, that generally rely on protein structure based interactions. Antibodies specific for human TLR2 and TLR6 were used by Chen et al. to demonstrate inhibition of IL 6 production by human PBMC in response to E. coli derived NS1. Using these antibodies, we found no effect of TLR2 or TLR6 blockade on the response to insect NS1 (Figure 2a) As expected for PBMC from four different donors, the absolute level of response to stimuli was variable, but in all cases the activity of insect derived NS1 was completely prevented by anti TLR4 antibody as well as the TLR4 antagonist, Rhodobacter sphaeroides LPS (LPS RS) (Figure 2a) in agreement with our previous work. Responses to the control TLR2/6 stimulus Pam2CSK4 and TLR4 stimulus LPS were sensitive to the respective anti TLR antibodies, as expected. However, none of these TLR inhibitory agents affected the response to E. coli NS1 (Figure 2a) suggesting that it may be contaminated with a variety of TLR ligands acting redundantly. The dominant contaminants from E. coli are likely to be LPS and a number of TLR2/1 agonists including triacylated lipopeptides. Despite using the same sources of E. coli derived NS1 and blocking antibodies we were unable to replicate the results of Chen et al. One possible explanation for their results is that the TLR targeting antibodies bound to cells may lead to cell death if used in combination with serum that has not been adequately heat inactivated to destroy complement function, whilst isotype control antibodies that do not bind cells would have no effect. It is notable that in one experiment shown by Chen et al. anti TLR2 and TLR6 blocking antibodies inhibited the PBMC response to LPS to the same extent as they inhibited the response to a TLR2/6 ligand. In contrast, a supplementary figure showed LPS response unaffected by the same antibodies, but this data does not appear to have been generated in parallel with the relevant experiments. A further assessment of TLR dependence was performed with bone marrow derived macrophages (BMMs) from Tlr knockout mice. Activity of the insect derived NS1 was lost in Tlr4 cells, but was unaffected by knockout of Tlr1 or Tlr6 (Figure 2b) Our prior work using Tlr2 BMM similarly showed no role for TLR2 in the stimulatory activity of purified insectderived NS1. Similar to results with PBMC cultures, E. coli derived NS1 at 10 mg/ml was strongly active, with this activity not abolished by any individual Tlr knockout. However at 1 mg/ml, its induction of IL 6 was TLR4 dependent. This was distinct from the human cell response, where TLR4 responses did not clearly dominate at this concentration of E. coli NS1 (Figure 2a) This may reflect greater sensitivity of the human cells to possible contaminants within the preparation. Overall, these results cannot be reconciled with those of Chen et al. who reported that the response to E. coli derived NS1 was completely lost in Tlr6 mouse macrophages. Any study proposing a new ligand for TLR activation must exclude microbial contaminants. Chen and co workers used a synthetic 6X His tag peptide (Abcam Cat. 14943) as a control for NS1, however this preparation is unlikely to provide an adequate experimental control for possible bacterial contaminants present in a recombinant protein purified from E. coli. We used a Limulus amoebocyte lysate (LAL) assay to estimate the LPS content in 1 mg/ml of the commercially sourced E. coli derived NS1 to be 0.55 EU/ml, whilst 10 mg/ml insect derived NS1 was below the limit of detection <0.1 EU/ml) The E. coli derived NS1 preparation was active in induction of IL 6 by PBMC at concentrations as low as 0.64 ng/ml NS1, which was approximately 1000 fold more potent than insect cell derived NS1 (Figures 3a and 3b) The LPS binding antibiotic polymyxin B had no effect on the response to insect cell derived NS1 (Figure 3a) showing a lack of any accessible LPS as being responsible for its activity. In contrast, E. coli derived NS1 activity was reproducibly inhibited by polymyxin B, but only at low concentrations of NS1 (Figure 3b) suggesting the presence of a number of immunostimulatory agents including LPS. LPS and Pam2CSK4 treatments were used as positive and negative controls for TLR4 and TLR2/6 activation and polymyxin B sensitivity (Figures 3c and 3d) The broad dose response curve seen with E. coli derived NS1 is also consistent with it containing a number of stimulatory contaminants. In contrast, purified insect cell derived NS1, ultrapure LPS and Pam2CSK4 showed saturation of responses within 1 2 log units (Figures 3a d) The molar concentrations required for response to insect NS1 were approximately 10 fold higher than for LPS (Figures 3a and 3c) Whilst NS1 is a somewhat less potent agonist, concentrations of circulating NS1 seen in dengue virus infected patients are higher than levels of circulating LPS in bacterial sepsis. The median LPS reported in sepsis is 300 pg/ml (0.03 nM assuming molecular weight of 10 kDa) ranging up to 5 ng/ml (0.5 nM) NS1 is detected in serum at ng/ml to mg/ml levels (1 mg/ml is 3.3 nM) Consequently, active concentrations of NS1 are within its physiological range. In addition, NS1 may be sequestered in vivo, for example by binding to endothelial cells, or masked by antibody, and its functional concentration may be higher than that measurable in serum. The results presented here clearly show the inadequacy of commercial bacterial expressed NS1 for studies of innate immune responses, due to protein misfolding and likely immunostimulatory contaminants. Although Chen et al. use", "author_names": [ "Naphak Modhiran", "Daniel Watterson", "Antje Blumenthal", "Alan G Baxter", "Paul R Young", "Katryn J Stacey" ], "corpus_id": 52997155, "doc_id": "52997155", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Dengue virus NS 1 protein activates immune cells via TLR 4 but not TLR 2 or TLR 6", "venue": "", "year": 2018 }, { "abstract": "BackgroundExposure to particulate matter (PM) is a significant risk factor for increased cardiopulmonary morbidity and mortality. The mechanism of PM mediated pathophysiology remains unknown. However, PM is proinflammatory to the endothelium and increases vascular permeability in vitro and in vivo via ROS generation.ObjectivesWe explored the role of tight junction proteins as targets for PM induced loss of lung endothelial cell (EC) barrier integrity and enhanced cardiopulmonary dysfunction.MethodsChanges in human lung EC monolayer permeability were assessed by Transendothelial Electrical Resistance (TER) in response to PM challenge (collected from Ft. McHenry Tunnel, Baltimore, MD, particle size >0.1 mm) Biochemical assessment of ROS generation and Ca2+ mobilization were also measured.ResultsPM exposure induced tight junction protein Zona occludens 1 (ZO 1) relocation from the cell periphery, which was accompanied by significant reductions in ZO 1 protein levels but not in adherens junction proteins (VE cadherin and b catenin) N acetyl cysteine (NAC, 5 mM) reduced PM induced ROS generation in ECs, which further prevented TER decreases and atteneuated ZO 1 degradation. PM also mediated intracellular calcium mobilization via the transient receptor potential cation channel M2 (TRPM2) in a ROS dependent manner with subsequent activation of the Ca2+ dependent protease calpain. PM activated calpain is responsible for ZO 1 degradation and EC barrier disruption. Overexpression of ZO 1 attenuated PM induced endothelial barrier disruption and vascular hyperpermeability in vivo and in vitro.ConclusionsThese results demonstrate that PM induces marked increases in vascular permeability via ROS mediated calcium leakage via activated TRPM2, and via ZO 1 degradation by activated calpain. These findings support a novel mechanism for PM induced lung damage and adverse cardiovascular outcomes.", "author_names": [ "Ting Wang", "Lichun Wang", "Liliana Moreno-Vinasco", "Gabriel D Lang", "Jessica H Siegler", "Biji Mathew", "Peter V Usatyuk", "Jonathan M Samet", "Alison Geyh", "Patrick N Breysse", "Viswanathan Natarajan", "Joe G N Garcia" ], "corpus_id": 6410824, "doc_id": "6410824", "n_citations": 71, "n_key_citations": 0, "score": 0, "title": "Particulate matter air pollution disrupts endothelial cell barrier via calpain mediated tight junction protein degradation", "venue": "Particle and Fibre Toxicology", "year": 2012 }, { "abstract": "This special issue is a selection of 15 papers reflecting recent advances in the molecular simulation of chemical reactions. The first part of this issue is devoted to new developments and applications of reactive force fields and reactive molecular dynamics (MD) simulation. Yunfeng Shi discusses a minimalist's reactive force field, known as the reactive state summation potential, which can be regarded as a 'reactive Lennard Jones' potential, and its application to the modelling of detonation, of the pyrolysis of activated carbon and of catalytic chemical reactions. Ziqi Tian, Jin Wen and Jing Ma discuss how reactive MD simulations can be used to model the collective switching process in azobenzenebased self assembled monolayers on a Au (111) surface. Xiaoxia Li, Zheng Mo, Jian Liu and Li Guo develop a new methodology by combining graphics processing unit enabled high performance computing with cheminformatics analysis in order to explore coal pyrolysis using reactive MD (ReaxFF MD) The second part of this issue focuses on the development on new simulation strategies and new simulation methods to identify reaction pathways and reaction intermediates. Paul M. Zimmerman discusses an automated simulation strategy for investigating multiple elementary step reaction mechanisms in chemical systems, by starting from a single input structure, seeking out nearby intermediates, optimising the proposed structure and then determining the kinetic viability of each elementary step. Shaohui Zheng and Jim Pfaendtner discuss the application of metadynamics to perform an enhanced sampling of chemical and biochemical reactions and provide detailed summaries of the method applied in various contexts including condensed phase and biological reactions. Styliani Consta and Anatoly Malevanets use different molecular simulation techniques to sample the activated processes of fragmentation and ion escapes and to shed light on the disintegration mechanisms of charged nanodroplets. Sophya Garashchuk, Jacek Jakowski and Vitaly Rassolov propose an approximate quantum trajectory dynamics method, based on a Bohmian formulation of the time dependent Schrodinger equation, and apply this approach to study systems with applications in biochemistry and in materials science. Franz Martinez and Gabriel Hanna discuss the assessment of approximate solutions of the quantum classical Liouville equation for the dynamics simulations of quantum subsystems embedded in classical environments and present results on photo induced electron transfer and on proton transfer. The third part of this issue examines the reactivity and catalytic properties of systems of nanoscopic dimensions. Using representative models of various supported nanoparticle systems, Eric D. Hermes, Glen R. Jenness and J.R. Schmidt perform computational studies based on density functional theory (DFT) to decouple the metal support interaction in terms of electronic and geometric effects, including the role of support oxygen vacancies and the reactivity of perimeter sites at the metal oxide boundary. Qingguo Meng, Jiangchao Chen and Dmitri Kilin use ab initio MD at the DFT level to carry out a systematic study of the sequential H2 dissociation of a Pd13H24 cluster and compare the catalytic activities of Pd nanoparticles for proton reduction. The fourth part focuses on furthering our understanding of electronic processes in solution. Katie W. Corum and Sara E. Mason test the reactivity of cations (Cu2th, Pb2th, Zn2th) and anions (SO4 Cl) to aqueous Al30 by using DFT methods with the aim of developing a molecular level understanding of geochemical model systems. Chun C. Mak and Gilles H. Peslherbe present a comprehensive overview of the development and application of state of the art first principles MD simulations to understand the results of femtosecond photoelectron spectroscopy experiments on [I(Solv)n] relaxation, and unveil the solvent specificity of excited anionic cluster relaxation and electron solvation. The last part of the issue discusses the latest developments on combined quantum classical methods. Building on the widely used combined QM/MM (quantum mechanics/molecular mechanics) methods in multi scale modelling, Soroosh Pezeshki and Hai Lin provide an overview of recently developed QM/MM algorithms towards the ultimate goal of establishing an open boundary between the QM and MM subsystems. Patrik R. Callis highlights selected classical MD in combination with QM (MD th QM) simulations of time dependent wavelength shifts in solvents and proteins, fluorescence quenching rates, dielectric compensation by water, heterogeneity of quenching rates and applications to protein folding. Feng Wang and Marawan Ahmed review applications of computational methods and rational molecule design,", "author_names": [ "Jerome Delhommelle" ], "corpus_id": 96188157, "doc_id": "96188157", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Recent advances in the molecular simulation of chemical reactions", "venue": "", "year": 2015 }, { "abstract": "1. Gailit JO, Siegel E, Frederiksen DW (1980) Possible superposed genes for identical proteins. Fed Proc 39:2011. 2. Gailit JO, Hellerqvist CG (1984) Cell adhesion to extracellular matrix in vitro. Fed Proc 43:1588. 3. Singer II, Scott S, Kawka DW, Gailit J, Ruoslahti E (1987) Fibronectin and vitronectin receptors are co localized at focal contacts of cultured human cells. J Cell Biol 105: 48a. 4. Freed E, Plow E, Ginsberg M, Gailit J, Ruoslahti E, Hunter T (1988) Phosphorylation of platelet glycoprotein IIIa and the b subunit of the vitronectin receptor on fibroblasts. J Cell Biol 107:152a. 5. Languino LR, Gailit J, Freed E, Hunter T, Ruoslahti E (1988) Vitronectin receptors from endothelial cells and osteosarcoma cells are functionally distinct. J Cell Biol 107:152a. 6. Freeze H, Haak R, Gailit J, Ruoslahti E (1990) Identification of integrin like molecules in Dictyostelium discoideum. FASEB J 4:A1789. 7. Clark RAF, Gailit J, Pierschbacher MD, Ruoslahti E (1990) Expression of fibronectin and vitronectin receptors in wound fibroblasts. J Cell Biochem Suppl 14A:160. 8. Clark RAF, Gailit J, Pierschbacher MD, Ruoslahti E (1990) Expression of fibronectin and vitronectin receptors in wound fibroblasts. J Invest Dermatol 94:514. 9. Tonnesen MG, Gailit J, Ruoslahti E, Clark RAF (1990) Integrin matrix receptor expression in the blood vessels of healing cutaneous wounds. J Invest Dermatol 94:586. 10. Tonnesen MG, Gailit J, Ruoslahti E, Clark RAF (1990) Integrin matrix receptor expression in the blood vessels of healing cutaneous wounds. J Cell Biochem Suppl 14E:216. 11. Clark RAF, Gailit J, Pierschbacher MD, Ruoslahti E (1990) Expression of fibronectin and vitronectin receptors in wound fibroblasts. Clin Res 38:222A. 12. Tonnesen MG, Gailit J, Ruoslahti E, Clark RAF (1990) Integrin matrix receptor expression in the blood vessels of healing cutaneous wounds. Clin Res 38:227A. 13. Clark RAF, Gailit J, Pierschbacher MD, Ruoslahti E (1990) Expression of fibronectin and vitronectin receptors in wound fibroblasts. Clin Res 38:630A. 14. Tonnesen MG, Gailit J, Ruoslahti E, Clark RAF (1990) Integrin matrix receptor expression in the blood vessels of healing cutaneous wounds. Clin Res 38:633A. 15. Clark RAF, Gailit JO, Pierschbacher M (1991) Human dermal fibroblasts adhere to the fibronectin CS III domain as well as the RGDS domain. Clin Res 39:511A. 16. Goligorsky MS, Gailit J (1991) a3 integrin in stressed renal epithelial cells. J Am Soc Nephrol 2:575. 17. Gailit J, Colflesh D, Rabiner I, Simone J, Goligorsky M (1992) Redistribution and dysfunction of integrins in stressed renal epithelial cells. J Am Soc Nephrol 3:631. 18. Bueller HA, Gailit JO, Clark RAF (1993) Integrin expression in fibroblast cell monolayers is increased by cytokines. J Invest Dermatol 100:558. 19. Tonnesen MG, Cheresh DA, Ede G, Gailit J, Clark RAF (1993) The integrin receptor avb3, which binds fibrin (fb) fibronectin (fn) and vitronectin (vn) is critical for wound healing. Clin Res 41:606A. 20. Gailit J, Clark RAF (1993) Platelet derived growth factor and inflammatory cytokines interleukin 1b, tumor necrosis factor a, and interferon g have differential effects on integrin receptors for collagen and fibronectin. Clin Res 41:607A. 21. Cullen B, Gailit J, Quigley JP, Clark RAF (1993) The effect of fibronectin and RGD peptides on plasminogen activator secretion from human dermal fibroblasts. Clin Res 41:608A. 22. Meng H, Marchese MJ, Gailit J, Clark RAF, Gruber BL (1994) Mast cells potentiate fibroblast adhesion molecule expression. FASEB J 8:A233. 23. Gailit J, Clark RAF (1994) Identification of integrin receptors used by fibroblasts for attachment to wound provisional matrix proteins. Clin Res 42:461A. 24. Tonnesen MG, Gailit J, Clark RAF (1994) Provisional matrix integrin receptor expression during granulation tissue formation and maturation. Clin Res 42:461A. 25. Xu J, Gailit J, Clark RAF (1994) Extracellular matrix (ECM) alters PDGF modulation of fibroblast integrins. Clin Res 42:462A. 26. Noiri E, Gailit J, Sheth D, Gurrath M, Kessler H, Miller F, Goligorsky MS (1994) Cyclic RGD peptides ameliorate ischemic acute renal failure (ARF) in rats. J Am Soc Nephrol 5:906. 27. Cullen B, Gailit J, Quigley JP, Clark RAF (1994) The effect of fibronectin and RGD peptides on plasminogen activator secretion from human dermal fibroblasts. J Invest Dermatol 102:529. 28. Tonnesen MG, Cheresh DA, Gailit J, Clark RAF (1994) The integrin receptor avb3, which binds fibrin (fb) fibronectin (fn) and vitronectin (vn) is critical for wound healing. J Invest Dermatol 102:529. 29. Garlick JA, Harrington R, Gailit J, Clarke RAF, Welgus HG, Parks WC, Taichman LB (1994) An organotypic model for reepithelialization. J Invest Dermatol 102:594. 30. Gailit J, Clark RAF (1994) Platelet derived growth factor and inflammatory cytokines interleukin 1b, tumor necrosis factor a, and interferon g have differential effects on integrin receptors for collagen and fibronectin. J Invest Dermatol 102:631. 31. Gailit J, Mosesson M, Clark RAF (1994) Identification of integrins used by fibroblasts for attachment to wound provisional matrix proteins. Mol Biol Cell Suppl 5:426a. 32. Xu J, Gailit J, Clark RAF (1995) Extracellular matrix alters PDGF regulation of fibroblast integrin receptor expression. J Invest Dermatol 104:590a. 33. McClain SA, Spetalnick AL, Simon M, Gailit J, Clark RAF (1995) Cutaneous wound healing requires fibroblast activation not fibrin clot maturation. J Invest Dermatol 104:665a. 34. Gailit J, Mosesson M, Clark RAF (1995) Identification of integrins used by fibroblasts for attachment to wound provisional matrix proteins. J Invest Dermatol 104:672a. 35. Tonesson MG, Gailit J, Clark RAF (1995) Provisional matrix integrin receptor expression during granulation tissue formation and maturation. J Invest Dermatol 104:672a. 36. Neff L, Gailit J, Baron R (1995) Ultrastructural demonstration of the av subunit of the vitronectin receptor in the sealing zone of resorbing osteoclasts. J Bone Miner Res 10:S239. 37. Gailit J, Mosesson M, Clark RAF (1995) Analysis of the interactions between human fibroblasts and fibrinogen. Mol Biol Cell Suppl 6:278a. 38. Gailit J, Clarke C, Flugman S, Mosesson M, Clark RAF (1996) Human fibroblasts bind fibrinogen at RGD and non RGD sites through avb3 integrin receptors. J Invest Dermatol 106:860. 39. Garlick J, Clark R, Gailit J, Sato A, Kubo M, Taichman L (1996) The distribution of integrin receptors, laminin 1 and laminin 5 in an organotypic wounding model. J Invest Dermatol 106:868. 40. Greiling D, Clark RAF, Gailit J (1996) In vitro assessment of the role of CD44 in fibroblast migration during wound repair. Mol Biol Cell Suppl 7:560a. 41. Suehiro K, Gailit J, Plow EF (1997) Endothelial cell integrin a5b1 binds to fibrinogen. Thromb Haemost Suppl: 172.", "author_names": [ "John Wiley" ], "corpus_id": 118265612, "doc_id": "118265612", "n_citations": 109, "n_key_citations": 10, "score": 0, "title": "A wiley interscience publication", "venue": "", "year": 1972 }, { "abstract": "3238 Assessment of Pgp function in leukemic blasts provides useful prognostic information regarding rates and treatment response and may be used for therapy selection in acute myeloid leukemia (AML) patients. Traditional assessment of Pgp function has utilized fluorescent indicators, such as DiOC2(3)or rhodamine 123 (Rh123) as surrogates for drug uptake and efflux. The objectives of this study were 1) to compare the performance of these two commonly used probes and representative therapeutic drugs in bidirectional in vitro permeability models, and 2) to validate the methodology for measuring Pgp+ status in patient cells when exposed to actual drugs susceptible to MDR [eg, daunorubicin (DNR) epirubicin (EPI) etoposide (VP 16) idarubicin (IDA) and mitoxantrone (MIT) versus the surrogate probes and amonafide, a topoisomerase II inhibitor, which is not an MDR substrate (O'Loughlin et al. Blood 2007) Pgp mediated differential transport was assessed in Caco 2 cells (Pgplow) or MDR1 MDCK (Pgphigh) monolayer cells as a bidirectional efflux/influx ratio (BD) calculated from separate apical to basolateral (A B) and basolateral to apical (B A) drug permeability measurements or as a monodirectional efflux/influx ratio (MD) based on the change in B A permeability, both performed before and after co administration of cyclosporin A (CSA) an inhibitor of Pgp. Our results indicated a significant correlation between BD and MD. The two methods afforded the same rank order in extent of efflux for the cohort of test compounds in both Pgplow and Pgphigh. The net efflux of amonafide was", "author_names": [ "Mydoanh Chau", "Ante Sven Lundberg", "Maria R Baer", "Harry P Erba", "Robert L Capizzi", "Alfred M Ajami" ], "corpus_id": 81243099, "doc_id": "81243099", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Multidrug resistance (MDR) in AML: Predicting P glycoprotein (Pgp) function by direct measurement of drug efflux is more effective than use of surrogate efflux indicators", "venue": "", "year": 2008 }, { "abstract": "The mode of action of venom from the endoparasitic wasp, Pimpla turionellae, was studied using in vitro assays and fluorescent microscopy. Crude venom was found to be cytotoxic to an embryonic cell line (BTI TN 5B1 4) derived from the cabbage looper, Trichoplusia ni. Susceptible cells displayed progressive morphological changes, such as retraction of cytoplasmic extensions, followed by Correspondence/Reprint request: Dr. David B. Rivers, Department of Biology, Loyola College in Maryland Baltimore MD, USA. E mail: drivers@loyola.edu Bridget Keenan et al. 2 rounding, swelling, and eventual vacuolization of the cytoplasm, all within 6 h of venom treatment. Cell death, however, did not occur for an additional 6 10 h at 27C. Pre treatment of cell monolayers with the osmotic protectants raffinose and sucrose afforded limited protection from the effects of venom: the presence of either saccharide yielded a time and dose dependent delay in the induction of cell rounding and swelling. The protection was not permanent as all pre treated cells eventually died by 24 36 h following incubation with crude venom. Venom induced changes in cell morphology were preceded by elevations in intracellular Ca as evidenced by labeling of cytosolic Ca with the fluorescent probe fluo 4 AM. Such changes in calcium homeostasis suggested involvement of calcium release channels on the endoplasmic reticulum. However, when array of potent calcium channel modulators (heparin, verapamil, caffeine, and xestospongin c) were tested, none were capable of preventing a rise in intracellular Ca or the venom associated morphological changes. Likewise, inhibitors of calcium channels typical of insect plasma membranes and use of culture media lacking calcium did not prevent increases in [Ca]i following venom exposure. Assessment of mitochondrial membrane potential (Psm) using rhodamine 123 revealed no significant qualitative changes due to wasp venom, and thus arguing that unregulated efflux of calcium into the cytosol did not account for the rise in [Ca]i.", "author_names": [ "B S Keenan", "Fevzi Uckan", "Ekrem Ergin", "David B Rivers", "Jay A Yoder" ], "corpus_id": 82512202, "doc_id": "82512202", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Morphological and biochemical changes in cultured cells induced by venom from the endoparasitoid, Pimpla turionellae.", "venue": "", "year": 2007 }, { "abstract": "A novel method for the preparation of biodegradable microspheres for protein drug delivery. Pareta R, Edirisinghe MJ. 2006. Journal of the Royal Society Interface 3:573 582. A novel multicompartimental system based on aminated poly(vinyl alcohol) microspheres/succinoylated pullulan microspheres for oral delivery of anionic drugs. Constantin M, Fundueanu G, Bortolotti F, Cortesi R, Ascenzi P, Menegatti E. 2007. International Journal of Pharmaceutics 330:129 137. A novel route to the preparation of poly(N isopropylacrylamide) microgels by using inorganic clay as a cross linker. Zhang QS, Zha LS, Ma JH, Liang BR. 2007. Macromolecular Rapid Communications 28:116 120. Adrenal axis suppression unrelated to the dynamics of dosing with beclomethasone monopropionate. Mulrennan SA, Hogg JS, Teoh RC, Morice AH. 2007. British Journal of Clinical Pharmacology 63:288 291. Aerosol mediated fabrication of porous thin films using ultrasonic nebulization. Walsh D, Arcelli L, Swinerd V, Fletcher J, Mann S, Palazzo B. 2007. Chemistry of Materials 19:503 508. Air liquid interface (ALI) culture of human bronchial epithelial cell monolayers as an in vitro model for airway drug transport studies. Lin HX, Li H, Cho HJ, Bian S, Roh HJ, Lee MK, Kim JS, Chung SJ, Shim CK, Kim DD. 2007. Journal of Pharmaceutical Sciences 96:341 350. Amphiphilic gels as a potential carrier for topical drug delivery. Prasad V, Kumar N, Mishra PR. 2007. Drug Delivery 14:75 85. Amphiphilic multi arm star block copolymers for encapsulation of fragrance molecules. Ternat C, Kreutzer G, Plummer CJG, Nguyen TO, Herrmann A, Ouali L, Sommer H, Fieber W, Velazco MI, Klok HA, Manson JAE. 2007. Macromolecular Chemistry and Physics 208:131 145. Anti inflammatory function of an in situ cross linkable conjugate hydrogel of hyaluronic acid and dexamethasone. Ito T, Fraser IP, Yeo Y, Highley CB, Bellas E, Kohane DS. 2007. Biomaterials 28:1778 1786. Antitumor efficacy of poly(brassylic acid pentadecandioic acid) copolymer. Guo WX, Long ZJ, Zhang Z, Hu LX. 2007. Materials Science Engineering C Biomimetic and Supramolecular Systems 27:51 56. Application of sucrose fatty acid esters in transdermal therapeutic systems. Csoka G, Marton S, Zelko R, Otomo N, Antal I. 2007. European Journal of Pharmaceutics and Biopharmaceutics 65:233 237. Assessment of subconjunctival and intrascleral drug delivery to the posterior segment using dynamic contrast enhanced magnetic resonance imaging. Kim SH, Galban CJ, Lutz RJ, Dedrick RL, Csaky KG, Lizak MJ, Wang NS, Tansey G, Robinson MR. 2007. Investigative Ophthalmology Visual Science 48:808 814. Behavior of temperature sensitive PNIPAM confined in polyelectrolyte capsules. Prevot M, Dejugnat C, Mohwald H, Sukhorukov GB. 2006. Chemphyschem 7:2497 2502. Bifunctional ligands that target cells displaying the alpha(v)beta(3) integrin. Owen RM, Carlson CB, Xu JW, Mowery P, Fasella E, Kiessling LL. 2007. Chembiochem 8:68 82. Bio functional micelles self assembled from a folate conjugated block copolymer for targeted intracellular delivery of anticancer drugs. Liu SQ, Wiradharma N, Gao SJ, Tong YW, Yang YY. 2007. Biomaterials 28:1423 1433. Bioavailability of riboflavin from a gastric retention formulation. Ahmed IS, Ayres JW. 2007. International Journal of Pharmaceutics 330:146 154. Biocompatible polymer vesicles from biamphiphilic triblock copolymers and their interaction with bovine serum albumin. Wittemann A, Azzam T, Eisenberg A. 2007. Langmuir 23:2224 2230. Biodegradable blend films based on two polysaccharide derivatives and their use as ibuprofen releasing matrices. Yi JZ, Zhang LM. 2007. Journal of Applied Polymer Science 103:3553 3559. Biodegradable polymers applied in tissue engineering research: a review. Martina M, Hutmacher DW. 2007. Polymer International 56:145 157. Blood brain barrier delivery. Pardridge WM. 2007. Drug Discovery Today 12:54 61. Boosting effect of bisphosphonates on osteoconductive materials: a histologic in vivo evaluation. Houshmand B, Rahimi H, Ghanavati F, Alisadr A, Eslami B. 2007. Journal of Periodontal Research 42:119 123. Calcium carboxymethyl chitosan hydrogel beads for protein drug delivery system. Liu ZH, Jiao YP, Zhang ZY. 2007. Journal of Applied Polymer Science 103:3164 3168. Characterization of chondroitin sulfate and its interpenetrating polymer network hydrogels for sustained drug release. Wang SC, Chen BH, Wang LF, Chen JS. 2007. International Journal of Pharmaceutics 329:103 109. Chitosan based interpolymeric pH responsive hydrogels for in vitro drug release. Abdelaal MY, Abdel Razik EA, Abdel Bary EM, El Sherbiny IM. 2007. Journal of Applied Polymer Science 103:2864 2874. Chitosan thioglycolic acid conjugate microspheres: their use for oral delivery of rEPO. Wang LQ, Cui FD. 2006. Journal of Drug Delivery Science and Technology 16:421 426. Clinical health information technologies and the role of Medicaid. Alfreds ST, Tutty M, Savageau JA, Young S, Himmelstein J. 2006. Health Care Financing Review 28:11 20. Colloidal stabilization of nanoparticles in concentrated suspensions. Studart AR, Amstad E, Gauckler LJ. 2007. Langmuir 23:1081 1090. Computational modeling to predict effect of treatment schedule on drug delivery to prostate in humans. Hu LJ, Au JLS, Wientjes MG. 2007. Clinical Cancer Research 13:1278 1287. Controlled release of vancomycin from thin sol gel films on titanium alloy fracture plate material. Radin S, Ducheyne P, 2007. Biomaterials 28:1721 1729. Controlled submicro particle formation of ampicillin by supercritical antisolvent precipitation. Tenorio A, Gordillo MD, Pereyra C, de la Ossa EJM. 2007. Journal of Supercritical Fluids 40:308 316. Core shell nanohydrogel structures as tunable delivery systems. Sahiner N, Alb AM, Graves R, Mandal T, McPherson GL, Reed WF, John VT. 2007. Polymer 48:704 711. Coronary stents: A materials perspective. Mani G, Feldman MD, Patel D, Agrawal CM. 2007. Biomaterials 28:1689 1710. Cross linking chitosan nanofibers. Schiffman JD, Schauer CL. 2007. Biomacromolecules 8:594 601. Customized PEG derived copolymers for tissue engineering applications. Tessmar JK, Gopferich AM. 2007. Macromolecular Bioscience 7:23 39. Cyanocobalamin (vitamin B 12) conjugates with enhanced solubility. Wang XY, Wei LH, Kotra LP. 2007. Bioorganic Medicinal Chemistry 15:1780 1787. Cyclodextrins and their pharmaceutical applications. Loftsson T, Duchene D. 2007. International Journal of Pharmaceutics 329:1 11.", "author_names": [], "corpus_id": 218876853, "doc_id": "218876853", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Literature Alerts", "venue": "", "year": 2007 } ]
sinter silver PZT
[ { "abstract": "Traditional lead free solder are widely employed for die attachment owing to low cost and easy process. The melting points of lead free solder are under the tolerable levels for silicon semiconductor devices. However, wide band gap semiconductors such as Gallium nitride (GaN) and Silicon carbide (SiC) with excellent electrical characteristics can be utilized for power electronics application at high power and high junction temperatures beyond 300degC [1] [2] Therefore, suitable die attachment materials which could bear the high junction temperatures play an important role for these wide band gap devices. However, the traditional techniques to interconnect (such as the solder alloys) are inappropriate due to the limits of operating temperatures and lower thermal conductivity. Silver sinter joining is well known for die bond material because of outstanding heat conductivity as well as excellent high temperature stability [3] [4] [5] In the study, a high thermal conductivity was obtained from the micro sized silver particles sintered at 280degC for 90 min without pressure [6] Besides, shear strength of bulk silver joint on bare copper substrate larger than 35 MPa were successfully achieved, which was produced a lower porosity less than 8.5%.In order to investigate the stability of pressure less sintered silver joints after high aging tests, we have carried out high temperature storage (HTS) at 175degC for 2000 hours. The power device characters with sinter material including the die shear strength (DSS) ratio of porosity, I V curve, surge current ability and thermal conductivity were verified in comparison to the initial state. In this study, mechanical shear over 28 MPa has been remained after aging at 175degC for 2000 hours. Furthermore, we have proven the electrical and thermal stability of non press sintered silver when environmental tests of high temperature storage. Cross section microstructure of the interface between sintered silver and copper substrate was examined by Scanning Electron Microscopy (SEM) The SEM images show that the formation of metallic bonds between the sintered joints and bare copper. Then, the sintered density of the joints were higher after high heat reliability test because of the micro silver particles composed complex porous networks as well as thick connection. In addition, it is carried out high thermal storage at 250degC for 500 hours, as well as the surge current ability still kept stable after the aging heating tests. To sum up, there is no doubt that the novel sintered silver paste without applied pressure has been one of the most promising candidates for high temperature and high power electronic applications in the future.", "author_names": [ "Yu-Wen Huang", "Min-Cheng Tsai", "P 4 Hsu", "Hao-Chiang Hsu", "Hsueh-Kuo Liao" ], "corpus_id": 59525487, "doc_id": "59525487", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Investigation of Non Pressure Sinter Silver in Power Module with High Accelerated Stress Aging Test", "venue": "2018 13th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT)", "year": 2018 }, { "abstract": "In this work we show the capabilities of non destructive testing by pulsed infrared thermography (PIRT) on large area silver sinter layers. This method can achieve a similar reliability in detecting delamination as SAM and X ray analysis. The great advantage of PIRT is its potential to become a tool for 100% in line inspections in the production line of power modules, whereas SAM and X ray are preferred as offline tools for reasons of costs, time or the need of a coupling medium. PIRT could help to replace vulnerable solder layers in power modules by much better performing silver sinter layers to enhance the reliability of those modules. By PIRT analysis on sample series with varied sinter process parameters and different sinter pastes, which will be compared to conventional failure analysis such as SAM and x ray, this work can show the quality of this method for the developing process of new sinter applications and for the following quality assessment in production lines.", "author_names": [ "Dan Ralf Wargulski", "Battist Rabay", "Adrian C Stelzer", "Jacek Rudzki", "Armin Hindel", "M Bast", "Dirk Busse", "Ellen Auerswald", "Mohamad Abo Ras" ], "corpus_id": 210695879, "doc_id": "210695879", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Paving the way for the replacement of solder interconnections in power electronics by silver sinter using pulsed infrared thermography", "venue": "2019 22nd European Microelectronics and Packaging Conference Exhibition (EMPC)", "year": 2019 }, { "abstract": "Silver nanoparticles (NPs) coated with silver stearate [CH3(CH2)16COOAg] have been prepared using a thermal decomposition method. Near spherical Ag NPs with average size of 4.4 nm were obtained after thermal decomposition at 523 K. The effects of the organic acid and thermal decomposition temperature on the characteristics of the Ag NPs were investigated. For stearic acid and lauric acid with straight chain structure, a longer chain of the organic acid contributes to the achievement of Ag NPs of smaller size, while ascorbic acid with cyclic structure results in relatively large sized (approximately 11.7 nm) Ag NPs. Small sized Ag NPs with uniform size distribution were obtained after thermal decomposition at temperature of 473 K or 523 K. However, after thermal decomposition at temperature of 573 K, the particle size of the Ag NPs increased and obvious aggregation occurred, which may be caused by the absence of the silver stearate coating. Low temperature sinter bonding of bare Cu was realized using Ag NP paste at 623 K under pressure of 5 MPa in air atmosphere. The microstructure of the joint revealed formation of a dense sintered Ag filler layer and its favorable interfacial bonding with the Cu substrates.", "author_names": [ "Yangwu Mao", "Yubo Duan", "Ke Wang", "Lixia Xi", "Quanrong Deng", "Geming Wang", "Shenggao Wang" ], "corpus_id": 107388421, "doc_id": "107388421", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Preparation of Ag Nanoparticles Coated with Silver Stearate for Low Temperature Sinter Bonding", "venue": "Journal of Electronic Materials", "year": 2019 }, { "abstract": "During the experiment, pressure less silver sintering pastes that can sinter using a conventional reflow oven for die attach applications were developed. This development makes it possible to produce die attach assemblies in a continuous and high throughput fashion for mass production. Different reflow profiles such as \"ramp up and peak\" and \"ramp up and plateau\" types were tested and high shear strength joints with no voids were obtained. For each sample, the sintering time was around twelve minutes or less, which is about one order of the magnitude that is presently used for box oven sintering time. Two sintering pastes, A and B, were developed. Paste A has been used to study the relationship between processing conditions (reflow oven sintering temperature and atmosphere such as air vs nitrogen) and the die attach structures (with varied substrate materials such as copper or active metal brazing (AMB) and surface metallization such as copper, silver, or gold) Under the same combined conditions of sintering temperature, atmosphere, and substrate type, the Ag metalized substrate gave the strongest joint shear strength. In comparison, Au metalized substrate displayed the weakest strength because of the formation of a \"depletion layer\" as a result of the diffusion of silver on gold surface, leaving behind a weak connection between sintered silver and Ag Au layer. For the above noble metal metallized surfaces, sintering in air normally results in stronger joint shear strength than that in a nitrogen atmosphere. On the bare Cu metallized surface with nitrogen sintering, increasing the sintering temperature and changing to paste B are two ways to increase joint shear strength. Sintering on an AMB substrate displays around 10Mpa higher shear strength than that on a Cu substrate, indicating the importance of surface morphology. When sintering at 250degC in air, oxygen can help accelerate the inter diffusion between Cu substrate and sintered Ag and enhance interfacial adhesion, increasing the shear strength. A higher sintering temperature reduces the adhesion due to the formation of large amounts of copper oxide; therefore, control of the optimum temperature range is key to obtaining a strong joint in air.", "author_names": [ "Sihai Chen", "Evan Wernicki", "S Wright", "Christine Labarbera", "Ning-Cheng Lee" ], "corpus_id": 214057879, "doc_id": "214057879", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "\"Drop in\" Conventional Reflow Oven Sinter Able Pressure Less Silver Paste for Die Attach Assembly Mass Production", "venue": "International Symposium on Microelectronics", "year": 2019 }, { "abstract": "Silver sintering become a mature interconnection technology for high reliability or high temperature electronic devices. Different sintering processes are applied depending upon application requirements, for instance pressure sintering process is optimized for elevated life time power modules. The pressure of the sintering process can be adjusted in order to modify the properties of the sinter layer. In general, higher pressure or temperature leads to higher Young's modulus. With respect to the lifetime of an interconnection, the Young's modulus, the dimension of the connected area and the CTE mismatch of the joint materials play an important role in temperature cycling. Thermo mechanical tension might not be reduced easily by the interconnection material if the Young's modulus of the material itself is high. A brittle die attach material might crack due to the bending of the package caused by the CTE mismatch of the used materials. This leads to a degradation of thermal conductivity and a reduced life time of the components, particularly on components which are operated at above 175degC. Silver sinter material with a reduced Young's modulus as well as an adjusted CTE is desired to avoid crack, especially for the interconnection of large areas. This paper shows the result of silver sinter paste with improved mechanical properties. By adding non silver particles to the sinter paste the Young's modulus became independent of process parameters and became stable against further thermal exposure. This investigation is part of the public project HHK funded by BMBF.", "author_names": [ "Wolfgang Schmitt", "Ly May Chew", "David Stenzel" ], "corpus_id": 201067682, "doc_id": "201067682", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Silver sinter paste for SiC bonding with improved mechanical properties", "venue": "2019 IEEE International Workshop on Integrated Power Packaging (IWIPP)", "year": 2019 }, { "abstract": "Silver sinter joining paste has been seen as the most promising candidate for die attachment materials of next generation power devices. However, there are still technique issues to be overcome before its actual utilization such as sinterability under various atmosphere and the lack of rapid sintering ability. In this research, on the basis of reported silver hybrid paste, an optimized paste composition which is composed of silver micron flakes, silver submicron particles, silver nanoparticles and ether type solvent has been established. The newly developed paste has proper viscosity which can inhibit the leakage tendency of solvent during mask printing. Its sintering property has been systematically evaluated and an omnipotent sinterability under various atmosphere has been observed. Moreover, the rapid sintering property drastically shorten the sintering temperature from at least 30 min to 10 min. These results suggest that the modified silver hybrid sinter joining paste can accelerate the further application of next generation power devices owing to its obvious process advantage and excellent performance.", "author_names": [ "Tomoya Egawa", "Hao Zhang", "Takanori Kobatake", "Yasuyuki Akai", "Chuantong Chen", "Katsuaki Suganuma" ], "corpus_id": 218468727, "doc_id": "218468727", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Sinterability improvement of hybrid silver sinter joining paste by adding silver nanoparticles", "venue": "2019 20th International Conference on Electronic Packaging Technology(ICEPT)", "year": 2019 }, { "abstract": "Development of sinter free stretchable conductive inks is critically important to expand the range of materials and applications for flexible electronics. However, conventional stretchable conductive inks require high temperature sintering, which may damage the heat frail substrates. In this study, we developed sinter free stretchable conductive inks composed of polystyrene block polybutadiene block polystyrene (SBS) and silver flakes in tetrahydrofuran (THF) The high volatility and polarity of THF induced the densification and alignment of silver flakes in the SBS matrix, where silver flakes with large surface area and high aspect ratio were formed into the multistacked structure, resulting in the increase of conductive pathways in the stretched wiring.", "author_names": [ "Takenori Nakanishi", "Kento Yamagishi", "Eiji Iwase", "Hiroyasu Iwata", "Shinji Takeoka", "Toshinori Fujie" ], "corpus_id": 182857783, "doc_id": "182857783", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Sinter free stretchable conductive inks composed of polystyrene block polybutadiene block polystyrene and silver flakes in tetrahydrofuran", "venue": "Applied Physics Express", "year": 2019 }, { "abstract": "Silver (Ag) nanoparticle based inks are frequently used in printed electronics to form conductive patterns, but often require high temperature sintering to achieve the optimum electrical conductivity, hindering their use in substrates with poor heat resistance. Herein, a three dimensional (3D) printing strategy to produce highly conductive Ag 3D architectures that can be sintered at low temperatures is reported. This strategy is based on the additive deposition of Ag nanoparticles and microflakes via extrusion based 3D printing with the Ag ink that involves poly(acrylic acid) (PAA) stabilized Ag nanoparticles, Ag microflakes, and NaCl a destabilizing agent. The designed Ag inks are stable and suitable for ink extrusion 3D printing. In chemical sintering, Cl can detach PAA from the Ag nanoparticle surface, enabling nanoparticle coalescence and sintering. An elevated annealing temperature induces increased NaCl density in the printed patterns and accelerates the surface and grain boundary diffusion of Ag atoms, contributing to enhance chemical sintering. On annealing at ~110 degC for 30 min, the printed structures exhibited an electrical conductivity of ~9.72 x 104 S cm 1, which is ~15.6% of that of bulk Ag. Complicated Ag architectures with diverse shapes were successfully fabricated on polymeric substrates. Several structural electronic applications were demonstrated by hybrid 3D printing combining our extrusion based 3D printing and conventional fused deposition modeling (FDM)", "author_names": [ "Jung Hyun Kim", "Sanghyeon Lee", "Muhammad Wajahat", "Jinhyuck Ahn", "Jaeyeon Pyo", "Won Suk Chang", "Seung Kwon Seol" ], "corpus_id": 202702379, "doc_id": "202702379", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "3D printing of highly conductive silver architectures enabled to sinter at low temperatures.", "venue": "Nanoscale", "year": 2019 }, { "abstract": "This study aims to utilize Simultaneous Thermal Analysis Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) along with respective differential curves to infer relative data points such as temperature and shape of peaks, duration and percentage of solvent outgassing to design and optimize curing profile with appropriate outgassing and sintering time and temperature, ramp up rate at shortest duration. Using different scan modes; isothermal and dynamic, five different curing profiles were derived and simulated to check thermal responses. The effectiveness of each profile was evaluated through curing of die attached units and the presence of die bulging and channeling voids were assessed through five point Bondline Thickness (BLT) SEM and SCAT. It was found out that gradual solvent outgassing at lower temperature and longer time, as well as choosing lower sintering temperature and ramp up rate could prevent formation of these anomalies. It was also proven that unoptimized curing profile triggers the occurrence and recurrence of die bulging and channeling voids.", "author_names": [ "Marty Lorgino D Pulutan", "Bobby Johns L Villacarlos" ], "corpus_id": 212646539, "doc_id": "212646539", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "On the Elimination of Die Attach Defects Occurrence Optimization of Silver Sinter Curing Profile Using Simultaneous Thermal Analyses", "venue": "2019 IEEE 21st Electronics Packaging Technology Conference (EPTC)", "year": 2019 }, { "abstract": "Die attach on power semiconductor using leadfree technique has attracted considerable interest. Silver sinter has demonstrated significant develop over the past years to be considered one of frontrunner non lead containing die attach solution. Pressure silver sintering by far offers superior thermal and electrical conductivity properties which enables power electronics applications to operate at high temperature. Eliminating precious metal finishing on substrate would represent significant compatibility to present supply chain and lower the entry barrier to adopt silver sinter solution. This paper explores the development of a safe to use micro Ag sinter paste for pressure sintering on bare Cu for power electronics packaging. We attached Ag metallized mechanical Si dies on silicon nitride active metal brazed copper substrates with Ag and Au metallization as well as without metallization by silver sintering at 230degC with a pressure of 10 MPa for 3 min. We observed that the average initial die shear strength for Ag metallized substrate is higher than that for Au metallized and bare Cu substrates. This observation points to the self diffusion of Ag is faster than the silver/gold and silver/copper interdiffusion. The average die shear strength for all the samples increased remarkable after temperature cycling test with a condition of 40degC/+150degC and after a long term storage at 250degC. It is highly likely that the sintering process is not yet completed under the mild sintering process conditions we used in this study and consequently Ag, Au and Cu continued to diffuse during temperature cycling test and high temperature storage and as a result strengthen the sintered joint. It is strongly believed that the sintering process is completed after a certain time of storage at 250degC as we observed no further increase in die shear strength after 250 h storage. The bending test results further confirm the increase of bonding strength by thermal cycling. It is worth noting that cohesive break in the Cu layer was observed for Ag metallized and bare Cu substrates after 1000 h storage at 250degC. Elemental analysis by energy dispersive X ray spectroscopy demonstrates that interdiffusion between Ag and Cu occurred during high temperature storage in which Cu from the substrate diffused into the silver sintered layer and concurrently Ag from the silver sintered layer diffused into the substrate. In contrast, we observed cohesive break in the sintered layer after 1000 h storage at 250degC for Au metallized substrate indicating that Au metallized layer acts as a barrier to prevent Cu from the substrate from diffusion into the silver sintered layer.", "author_names": [ "Ly May Chew", "Wolfgang Schmitt", "Christian Schwarzer", "Jens Nachreiner" ], "corpus_id": 51984909, "doc_id": "51984909", "n_citations": 13, "n_key_citations": 1, "score": 0, "title": "Micro Silver Sinter Paste Developed for Pressure Sintering on Bare Cu Surfaces under Air or Inert Atmosphere", "venue": "2018 IEEE 68th Electronic Components and Technology Conference (ECTC)", "year": 2018 } ]
An evaluation of effects of molding compound properties on reliability of Ag wire components
[ { "abstract": "Silver (Ag) bond wires are increasingly used in semiconductor components to replace gold (Au) bond wires, and applications for these components are expanding from consumer to high reliability electronic systems. To assess the impact of this technology transition on the overall component reliability, extended reliability testing beyond the typical JEDEC component qualification testing is needed. Additionally, key packaging materials, such as molding compounds, also need to be re evaluated as they may interact with the Ag wire bond differently from Au wire bonds and introduce new failure mechanisms under different conditions. In this work, we investigate the impact of molding compound chemistry and testing condition on the reliability performance by testing a range of commercially available Ag wire bonded components. The composition of the molding compound is analyzed and concentrations of key elements that contribute to bond wire bonding pad interface corrosion are reported. These components are subjected to acceleration tests, including temperature humidity bias and high temperature storage tests. As a control, Au wire bonded components are also subjected to the same acceleration tests. Failure rates and mechanisms for the experimental conditions are determined based on resistance measurements and cross section analyses of microstructures and discussed in terms of interactions between the test conditions, the chemistry of the molding compounds, and wire bond composition. Reliability testing and analytical results demonstrate the importance of controlling molding compounds composition and properties and provide guidelines for the selection of these materials for different applications. In particular, improved and better controlled packaging material formulations will be needed for high reliability and mission critical electronic systems to ensure the long term reliability of components using Ag bond wires.", "author_names": [ "Keisuke Yazawa", "Matthew Parsons", "Azzedin Jackson", "Wenhao Chen", "Alexander Campbell", "John E Blendell", "Carol A Handwerker", "Peng Su" ], "corpus_id": 19695383, "doc_id": "19695383", "n_citations": 1, "n_key_citations": 0, "score": 2, "title": "An Evaluation of Effects of Molding Compound Properties on the Reliability of Ag Wire Bonded Components", "venue": "2017 IEEE 67th Electronic Components and Technology Conference (ECTC)", "year": 2017 }, { "abstract": "Adhesion and interface compositions of epoxy phenolic molding compounds (EMCs) for high temperature plastic packages are studied. Interfaces are obtained by molding two EMCs onto aluminum oxide hydroxide surfaces (oxide onto thin film of AlSiCu) and two die passivation layers consisting of fluorinated polyimide and cyclotene. One compound (A) is a \"green\" type, containing organic phosphorous based flame retardant, and the other compound (B) is a conventional type containing antimony (III) oxide and bromined resin flame retardants. A high temperature storage test at 250 degC is employed to study chemical modifications occurring at the previously mentioned interfaces. A high temperature reverse bias test at 225 degC is employed to study the influences of the EMC chemical formulations on the reliability of plastic packages for SiC based power MOS devices. Green compound A shows poor adhesion onto Al oxide and high adhesion strength onto both polymer passivations. The failure mechanism is mainly cohesive on the polymer passivations. The conventional compound B shows a high degree of delamination because of poor adhesion compared with the green compound. SiC based power MOS devices assembled in plastic packages with compound A show better reliability under HTRB test at 225 degC compared with compound B.", "author_names": [ "Antonino Scandurra", "Giuseppe Francesco Indelli", "Roberto Zafarana", "Angelo Cavallaro", "Emanuele Scrofani", "Jean Paul Giry", "Sebastiano Russo", "Mietek Bakowski" ], "corpus_id": 34362609, "doc_id": "34362609", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Molding Compounds Adhesion and Influence on Reliability of Plastic Packages for SiC Based Power MOS Devices", "venue": "IEEE Transactions on Components, Packaging and Manufacturing Technology", "year": 2013 }, { "abstract": "Wire bonding on Al pad packages with an innovative annealing twinned Ag 8Au 3Pd alloy wire results in a sufficient interfacial intermetallic layer at the initial as bonded stage, while its growth during the further temperature cycling test and pressure cooker test is very slow. Even after prolonged high temperature storage at 150degC for 500 h, the thickness of its intermetallics is only around 1.7 mm. In contrast, a very thin CuAl<sub>2</sub> intermetallic layer appears at the interface of the Pd coated Cu wire bonded package, and a thick layer of Au<sub>8</sub>Al<sub>3</sub> intermetallic compounds forms in the Au wire package, which grows to a thickness of around 4.0 mm after high temperature storage at 150<sup>deg</sup>C for 500 h. Energy dispersive X ray spectrometry analyses indicate that AgAl<sub>2</sub> Au<sub>8</sub>Al<sub>3</sub> and CuAl<sub>2</sub> are the main intermetallic phases formed in the packages bonded with Ag 8Au 3Pd, and Au and Pd coated Cu wires, respectively. However, an additional Pd containing Ag<sub>2</sub>Al layer found at the AgAl<sub>2</sub>/Al interface of Ag 8Au 3Pd wire bonded package can interrupt its intermetallic reaction, and the annealing twins can further slow the intermetallic growth.", "author_names": [ "Tung-Han Chuang", "Che-Cheng Chang", "Chien-Hsun Chuang", "Jun-Der Lee", "Hsing-Hua Tsai" ], "corpus_id": 19874255, "doc_id": "19874255", "n_citations": 30, "n_key_citations": 1, "score": 0, "title": "Formation and Growth of Intermetallics in an Annealing Twinned Ag 8Au 3Pd Wire Bonding Package During Reliability Tests", "venue": "IEEE Transactions on Components, Packaging and Manufacturing Technology", "year": 2013 }, { "abstract": "Solder materials demonstrate evolving microstructure and mechanical behavior that changes significantly with environmental exposures such as isothermal aging and thermal cycling. These aging effects are greatly exacerbated at higher temperatures typical of thermal cycling qualification tests for harsh environment electronic packaging. In the current study, mechanical measurements of thermal aging effects and material behavior evolution of lead free solders have been performed. Extreme care has been taken so that the fabricated solder uniaxial test specimens accurately reflect the solder materials present in actual lead free solder joints. A novel specimen preparation procedure has been developed where the solder uniaxial test specimens are formed in high precision rectangular cross section glass tubes using a vacuum suction process. The tubes are then sent through a SMT reflow to re melt the solder in the tubes and subject them to any desired temperature profile (i.e. same as actual solder joints) Using specimens fabricated with the developed procedure, isothermal aging effects and viscoplastic material behavior evolution have been characterized for 95.5Sn 4.0Ag 0.5Cu (SAC405) and 96.5Sn 3.0Ag 0.5Cu (SAC305) lead free solders, which are commonly used as the solder ball alloy in lead free BGAs and other components. Analogous tests were performed with 63Sn 37Pb eutectic solder samples for comparison purposes. In our total experimental program, samples have been solidified with both reflowed and water quenching temperature profiles, and isothermal aging has been performed at room temperature (25 degC) and elevated temperatures (100 degC, 125 degC and 150 degC) In this paper, we have concentrated on reporting the results of the room temperature aging experiments. Variations of the temperature dependent mechanical properties (elastic modulus, yield stress, ultimate strength, creep compliance, etc. were observed and modeled as a function of room temperature aging time. Microstructural changes during room temperature aging have also been recorded for the solder alloys and correlated with the observed mechanical behavior changes", "author_names": [ "Hongtao Ma", "Jeffrey C Suhling", "Pradeep Lall", "Michael J Bozack" ], "corpus_id": 29438321, "doc_id": "29438321", "n_citations": 141, "n_key_citations": 21, "score": 0, "title": "Reliability of the aging lead free solder joint", "venue": "56th Electronic Components and Technology Conference 2006", "year": 2006 }, { "abstract": "Technical Introduction to the Second Edition. Ultrasonic Bonding Systems and Technologies (Including Ultrasonic Wire Bonding Mechanism) Some Aspects of Bonding Wire Characteristics That can Affect Bonding, Reliability, or Testing. Wire Bond Testing. Gold Aluminum Intermetallic Compounds and Other Metallic Interface Reactions Encountered in Wire Bonding. Bond Failures Resulting from Gold Plating Impurities and Conditions. Cleaning to Improve Bondability and Reliability. Mechanical Problems in Wire Bonding. High Yield and Fine Pitch Wire Bonding. Wire Bonding to Multichip Modules and Other Soft Substrates. Glossary. Index.", "author_names": [ "George G Harman" ], "corpus_id": 133630605, "doc_id": "133630605", "n_citations": 391, "n_key_citations": 33, "score": 0, "title": "Wire Bonding in Microelectronics: Materials, Processes, Reliability, and Yield", "venue": "", "year": 1997 }, { "abstract": "Customers demand various functions from their applications and, in order to satisfy these demands, module packages must be multifunctional. This applies to power module packages that include power devices, components and control ICs. The modules must also have substrates in order dissipate heat from operating power chips as well as a PCB to create multifunctional circuits. Occasionally, specific clips are used instead of wire interconnections and the inner structures of the power module packages become complicated by a customer's design requests. When those power module packages accept epoxy molding compound (EMC) it may become difficult to achieve good `flowability, perfect molded packages, and stable wire sweep index and it may also be hard to avoid wire sagging risk. Finite element analysis (FEA) for semiconductor encapsulation early in the design phase is now essential to finding out target designs and proper quality of flow. FEA also helps to recommend proper runner systems, gate design, and the number of gates, which also helps to save time and money when producing the initial mold die. This paper will compare and discuss the limitations of the flow pattern, wire sweep, air vent effect, and air trap between the result of commercial FEA software, Moldflow(tm) and the real samples.", "author_names": [ "Taekkeun Lee", "Aimee Lim", "Young-sun Ko", "Taewoo Lee", "Byoungok Lee" ], "corpus_id": 13325350, "doc_id": "13325350", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "The evaluation of flowability and wire sweep by epoxy molding compound for power module packages using Moldflow(tm)", "venue": "2013 14th International Conference on Thermal, Mechanical and Multi Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)", "year": 2013 }, { "abstract": "1. Introduction 2. The structure of cellular solids 3. Material properties 4. The mechanics of honeycombs 5. The mechanics of foams: basic results 6. The mechanics of foams refinements 7. Thermal, electrical and acoustic properties of foams 8. Energy absorption in cellular materials 9. The design of sandwich panels with foam cores 10. Wood 11. Cancellous bone 12. Cork 13. Sources, suppliers and property data Appendix: the linear elasticity of anisotropic cellular solids.", "author_names": [ "Lorna J Gibson", "M F Ashby" ], "corpus_id": 227301995, "doc_id": "227301995", "n_citations": 7937, "n_key_citations": 242, "score": 0, "title": "Cellular solids: Structure properties", "venue": "", "year": 1988 }, { "abstract": "Free air ball processed using coated silver (Ag) wire is soft similar to gold (Au) wire and enables bonding of stacked devices with over hangs. The bonded ball shear/pull, dimensions and stitch pull satisfied internal specifications and customer requirements including folded loop. Moreover, reliability of coated Ag wire bonds when molded using green epoxy mold compound (EMC) containing chlorine (Cl) \\lt15$ppm, sulfur (S) \\lt10$ppm, formulated with ion catcher and pH between 5 and 7, free of bromine and antimony, revealed reliable bonds. Two of the case studies of coated Ag ball bonds exhibit:*No failure until 3000h on high temperature storage (HTS) test at $175^\\circ}\\mathrm{C} and $150^\\circ}\\mathrm{C}*No failure until 1000h on unbiased highly accelerated stress test (uHAST) at $110^\\circ}\\mathrm{C} 85%RH*No failure until 504h on biased HAST at $130^\\circ}\\mathrm{C} 85%RH, +20V*No failure until 384h on uHAST, 2000h on HTS at $150^\\circ}\\mathrm{C} and 2000cycles on thermal cycling at 55^\\circ}\\mathrm{C} to 125^\\circ}\\mathrm{C}*Examining EMC formulated with pH 3 to 6 passed 2000h on HTS testing at $175^\\circ}\\mathrm{C} thereafter bond failed and showed high electrical resistanceThe reported results are based on electrical contact resistance measurement for the condition not to reduce below 10% of time zero bond resistance. The slower failure rate of Ag ball bonds showed EMC formulated with 5 to 7 pH is compatible than formulated with 3 to 5 pH.", "author_names": [ "Sarangapani Murali", "B Senthilkumar", "Tan Swee Seng Eric", "Wong Chin Yeung Jason" ], "corpus_id": 67876612, "doc_id": "67876612", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Coated Silver Wire Bond: Reliability of Epoxy Molded Device", "venue": "2018 IEEE 20th Electronics Packaging Technology Conference (EPTC)", "year": 2018 }, { "abstract": "Gold is commonly used in the field of electronic manufacturing as bonding wire that connects the IC chip and circuit board. The effect of trace elements on the mechanical properties of 4N gold wire has not been widely investigated for some years despite the important of wire bonding and the move towards fine pitch applications. The objective of this study is to determine the effect of mechanical properties of two type of gold wire (wire A and wire B) on looping and pull strengths. Both wires with diameter of 25.4mm were bonded using K&S Maxum by maintaining the temperature at 200oC. Due to the element analysis, atomic percentage of Ca in wire B is higher than wire A. Pull strength increase with the increasing of the trace element. The higher pull strength of wire B could improve the yield strength, elastic modulus and recrytallization temperature. Keyword: Wire bonding, Ultrasonic (USG) current, QFN packaging, ball bonding", "author_names": [ "Azman Jalar", "S A Radzi", "Shahrum Shah bin Abdullah", "Mohd Faridz Mod Yunoh", "Mohamad Firdaus Rosle" ], "corpus_id": 201054292, "doc_id": "201054292", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Effect of mechanical properties of gold wire on looping behavior and pull strength for QFN Stacked Die Package", "venue": "", "year": 2009 }, { "abstract": "Silicon carbide (SiC) power modules with Ag sinter bonding die attach were designed on the basis of thermal stress analysis for reliable high temperature operations. Both the finite element analysis (FEA) simulations and preliminary experiments confirmed that inserting the direct bonded copper (DBC) substrates can effectively reduce the maximum thermal stress in the module. A prototype SiC power module using sintered Ag die attach with a DBC substrate was designed and fabricated. The modules exhibited excellent durability in power cycling between 65 degC and 250 degC up to 20 000 cycles. FEA calculations of cumulative thermal strain and stress distributions adequately predicted the initial cracking position in the specimens after prolonged power cycles, observed by scanning electron microscopy.", "author_names": [ "Kazuhiko Sugiura", "Tomohito Iwashige", "Kazuhiro Tsuruta", "Chuantong Chen", "Shijo Nagao", "Tsuyoshi Funaki", "Katsuaki Suganuma" ], "corpus_id": 94793744, "doc_id": "94793744", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Reliability Evaluation of SiC Power Module With Sintered Ag Die Attach and Stress Relaxation Structure", "venue": "IEEE Transactions on Components, Packaging and Manufacturing Technology", "year": 2019 } ]
Decomposability in knowledge structures
[ { "abstract": "We use patent data from the worldwide semiconductor industry from 1984 to 1994 to study the effect of the structure of organizational knowledge bases, or the patterns of coupling between their elements of technical knowledge, on the usefulness of inventions and knowledge base malleability. We argue that organizational variations in coupling patterns between knowledge elements can be reflected in a spectrum of knowledge base structures varying from fully decomposable (the knowledge base is composed of distinct clusters of knowledge elements coupled together with no significant ties between clusters) through nearly decomposable (knowledge clusters are discernable but are connected through cross cluster couplings) to non decomposable (no knowledge clusters emerge, as the couplings are pervasively distributed) and that organizations may differ in the way they use their knowledge because of variations in their knowledge base structure, rather than because of differences in the knowledge elements themselves. Results show that a nearly decomposable knowledge base increases the usefulness of the inventions generated from it, as measured by patent citations, and also the knowledge base's malleability or capacity for change.", "author_names": [ "Sai Yayavaram", "Gautam Ahuja" ], "corpus_id": 146242071, "doc_id": "146242071", "n_citations": 300, "n_key_citations": 32, "score": 1, "title": "Decomposability in Knowledge Structures and Its Impact on the Usefulness of Inventions and Knowledge base Malleability", "venue": "", "year": 2008 }, { "abstract": "PRELIMINARIES: BASIC MATHEMATICAL NOTIONS. PROBABILITY. Basic Notions. Independence and Conditional Probability: Events. Independence and Conditional Probability: Two Random Variates. Independence and Conditional Probabilities: Random Fields. Log Linear Representations of Probability Distributions of Random Fields. Appendix: Where Does the Probability Come From? GRAPHS AND PROBABILITY. Graphs. From Hierachial Log Linear Models to Graphical Representation of Probability Distributions of Random Fields. Markov Properties. Decomposability and Collapsibility. Decomposability and Approximation. Appendix: Some Additional Facts Concerning Graphs. DECISION MAKING UNDER UNCERTAINTY. Decision Task. Decision Under Ignorance. Maximum Entropy Principle. Minimax Principle. LOCAL COMPUTATIONS WITH PROBABILITIES ON GRAPHICAL STRUCTURES AND INFLUENCE DIAGRAMS. Causal Graphs and Conditional Probability Tables. Local Representation of Probabilities. Local Computations: Inference Engine. Local Computations: Some Technicalities. Shachter's Method. KNOWLEDGE INTEGRATION METHODS. Completeness of Input Knowledge. Optimal Decision. Lagrange Multiplers Method. Iterative Proportional Fitting Procedure. D.S.S. Approximations. Studeng's Method. AN INTRODUCTION TO COMPOSITIONAL SYSTEMS. Basic Definitions and Assumptions on Compositional Systems. Some Properties of Combining Functions. Backward Chaining. Three Valued Systems. The Most Modest Runs. Additional Information on Propositional Logic. COMPOSITIONAL SYSTEMS: AN ALGEBRAIC ANALYSIS. Compositional Systems and Ordered Abelian Groups. Comparative Properties of Compositional Systems. Finitely Generated Ordered Abelian Groups. Where Are Weights of Rules From? A PROBABILISTIC ANALYSIS OF COMPOSITIONAL SYSTEMS. Uncertainty and Probability in Classical Systems. Compositional Systems and Log Linear Representation. Compositional Systems and Graphical Models: The Method of Guarded Use. THE DEMPSTER SHAFER THEORY OF EVIDENCE AND ITS USE IN EXPERT SYSTEMS. An Introduction to Dempster Shafer Theory. Dempster Shafer Theory and Local Computations. Belief Functions and Compositional Systems. ESTIMATION OF PROBABILITIES AND STRUCTURES. Estimation of Probabilities. Estimation of Structures. References.", "author_names": [ "Petr Hajek", "Tomas Havranek", "Radim Jirousek" ], "corpus_id": 36855287, "doc_id": "36855287", "n_citations": 201, "n_key_citations": 21, "score": 0, "title": "Uncertain information processing in expert systems", "venue": "", "year": 1992 }, { "abstract": "Abstract In knowledge space theory a knowledge structure provides a deterministic representation of the implications among the items in a given set Q Concrete procedures for the efficient assessment of knowledge by means of a knowledge structure have been proposed by Doignon and Falmagne [Falmagne, J. C. Doignon, J. P. (1988a) A class of stochastic procedures for the assessment of knowledge. British Journal of Mathematical and Statistical Psychology, 41, 1 23; Falmagne, J. C. Doignon, J. P. (1988b) A markovian procedure for assessing the state of a system. Journal of Mathematical Psychology, 32, 232 258] The primitive idea at the core of such procedures is that the (correct or wrong) answers of a student to a subset A Q of items could be inferred from the answers to a subset B Q of items that were previously presented to that student. Since B provides information about A from the viewpoint of the teacher these two subsets are not independent. This idea of dependence vs. independence is formalized in this paper in terms of an independence relation on the power set of Q A nice characterization of this relation allows to express an arbitrary knowledge structure as the combination of a number of substructures each of which is independent of each other. An algorithm is then proposed which checks for independence in a knowledge structure and decomposes this last into a collection of independent substructures.", "author_names": [ "Luca Stefanutti" ], "corpus_id": 122140099, "doc_id": "122140099", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "A characterization of the concept of independence in knowledge structures", "venue": "", "year": 2008 }, { "abstract": "Knowledge graphs contain knowledge about the world and provide a structured representation of this knowledge. Current knowledge graphs contain only a small subset of what is true in the world. Link prediction approaches aim at predicting new links for a knowledge graph given the existing links among the entities. Tensor factorization approaches have proved promising for such link prediction problems. Proposed in 1927, Canonical Polyadic (CP) decomposition is among the first tensor factorization approaches. CP generally performs poorly for link prediction as it learns two independent embedding vectors for each entity, whereas they are really tied. We present a simple enhancement of CP (which we call SimplE) to allow the two embeddings of each entity to be learned dependently. The complexity of SimplE grows linearly with the size of embeddings. The embeddings learned through SimplE are interpretable, and certain types of background knowledge can be incorporated into these embeddings through weight tying. We prove SimplE is fully expressive and derive a bound on the size of its embeddings for full expressivity. We show empirically that, despite its simplicity, SimplE outperforms several state of the art tensor factorization techniques. SimplE's code is available on GitHub at this https URL.", "author_names": [ "Seyed Mehran Kazemi", "David L Poole" ], "corpus_id": 3674966, "doc_id": "3674966", "n_citations": 247, "n_key_citations": 67, "score": 0, "title": "SimplE Embedding for Link Prediction in Knowledge Graphs", "venue": "NeurIPS", "year": 2018 }, { "abstract": "Abstract Achieving efficient disinfection of waterborne pathogens with minimized harmful disinfection byproducts demands a facile, cost effective, and environmentally friendly technology. Recently, photocatalytic water disinfection has attracted an ever growing worldwide attention due to its powerful oxidative capability and promising potential in solar energy utilization. Among waterborne pathogens, viruses, which have been found with very small sizes, high risks of illness, and resistant to environmental inactivation/decomposition, pose a great threat to public health. Over the past a few decades, efforts have been made to employ photocatalysis to achieve effective viral inactivation. Though photocatalysis has been comprehensively reviewed for bacterial disinfection, photocatalytic disinfection of viruses with quite different compositions, structures, and resistance to oxidative stress compared to bacteria was not systematically documented. Here, we present an overview of antiviral effects of a wide range of photocatalysts, including TiO2 based, metal containing (other than TiO2) and metal free photocatalysts. Moreover, the development of photocatalytic reactors for viral inactivation is summarized to promote practical engineering applications for water disinfection. In addition, key mechanisms that determine the performance of photocatalytic viral disinfection are reviewed. Future perspectives of research opportunities and challenges in photocatalytic viral disinfection are also included. This review will shed light on the development and implementation of sustainable disinfection strategies for controlling waterborne viruses in the future.", "author_names": [ "Chi Zhang", "Yi Li", "Danmeng Shuai", "Yun Shen", "Dawei Wang" ], "corpus_id": 105845809, "doc_id": "105845809", "n_citations": 79, "n_key_citations": 3, "score": 0, "title": "Progress and challenges in photocatalytic disinfection of waterborne Viruses: A review to fill current knowledge gaps", "venue": "", "year": 2019 }, { "abstract": "In recent years, different web knowledge graphs, both free and commercial, have been created. Knowledge graphs use relations between entities to describe facts in the world. We engage in embedding a large scale knowledge graph into a continuous vector space. TransE, TransH, TransR and TransD are promising methods proposed in recent years and achieved state of the art predictive performance. In this paper, we discuss that graph structures should be considered in embedding and propose to embed substructures called \"one relation circle\" (ORC) to further improve the performance of the above methods as they are unable to encode ORC substructures. Some complex models are capable of handling ORC structures but sacrifice efficiency in the process. To make a good trade off between the model capacity and efficiency, we propose a method to decompose ORC substructures by using two vectors to represent the entity as a head or tail entity with the same relation. In this way, we can encode the ORC structure properly when apply it to TransH, TransR and TransD with almost the same model complexity of themselves. We conduct experiments on link prediction with benchmark dataset WordNet. Our experiments show that applying our method improves the results compared with the corresponding original results of TransH, TransR and TransD.", "author_names": [ "Wen Zhang" ], "corpus_id": 18928847, "doc_id": "18928847", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Knowledge Graph Embedding with Diversity of Structures", "venue": "WWW", "year": 2017 }, { "abstract": "Knowledge graphs are structured representations of real world facts. However, they typically contain only a small subset of all possible facts. Link prediction is a task of inferring missing facts based on existing ones. We propose TuckER, a relatively straightforward but powerful linear model based on Tucker decomposition of the binary tensor representation of knowledge graph triples. TuckER outperforms previous state of the art models across standard link prediction datasets, acting as a strong baseline for more elaborate models. We show that TuckER is a fully expressive model, derive sufficient bounds on its embedding dimensionalities and demonstrate that several previously introduced linear models can be viewed as special cases of TuckER.", "author_names": [ "Ivana Balazevic", "Carl Allen", "Timothy M Hospedales" ], "corpus_id": 59316623, "doc_id": "59316623", "n_citations": 180, "n_key_citations": 67, "score": 0, "title": "TuckER: Tensor Factorization for Knowledge Graph Completion", "venue": "EMNLP", "year": 2019 }, { "abstract": "Generating long and semantic coherent reports to describe medical images poses great challenges towards bridging visual and linguistic modalities, incorporating medical domain knowledge, and generating realistic and accurate descriptions. We propose a novel Knowledge driven Encode, Retrieve, Paraphrase (KERP) approach which reconciles traditional knowledge and retrieval based methods with modern learning based methods for accurate and robust medical report generation. Specifically, KERP decomposes medical report generation into explicit medical abnormality graph learning and subsequent natural language modeling. KERP first employs an Encode module that transforms visual features into a structured abnormality graph by incorporating prior medical knowledge; then a Retrieve module that retrieves text templates based on the detected abnormalities; and lastly, a Paraphrase module that rewrites the templates according to specific cases. The core of KERP is a proposed generic implementation unit Graph Transformer (GTR) that dynamically transforms high level semantics between graph structured data of multiple domains such as knowledge graphs, images and sequences. Experiments show that the proposed approach generates structured and robust reports supported with accurate abnormality description and explainable attentive regions, achieving the state of the art results on two medical report benchmarks, with the best medical abnormality and disease classification accuracy and improved human evaluation performance.", "author_names": [ "Christy Y Li", "Xiaodan Liang", "Zhiting Hu", "Eric P Xing" ], "corpus_id": 59276384, "doc_id": "59276384", "n_citations": 55, "n_key_citations": 11, "score": 0, "title": "Knowledge driven Encode, Retrieve, Paraphrase for Medical Image Report Generation", "venue": "AAAI", "year": 2019 }, { "abstract": "Landfills are a vital component of our waste handling processes. Our lack of knowledge on the microbial processes in these systems, however, hampers our ability to design the next generation of landfills that: (1) enhance the rate and extent of waste decomposition, (2) produce byproducts of some value (e.g. methane that can be used for energy generation) and, (3) minimize their overall impact on driving climate change through the emission of greenhouse gases. In this review, the current state of knowledge the microbial community structure and activity in both the refuse and overlying cover soils is discussed, and suggestions provided for future research in this critical aspect of our infrastructure.", "author_names": [ "Jeremy D Semrau" ], "corpus_id": 689200, "doc_id": "689200", "n_citations": 48, "n_key_citations": 1, "score": 0, "title": "Current knowledge of microbial community structures in landfills and its cover soils", "venue": "Applied Microbiology and Biotechnology", "year": 2010 }, { "abstract": "Customer requirements provide objectives and constraints for all phases of the product development process. For complex system products with a high degree of customization, it is no mean task to ensure that the right persons at the right time have ready access to the selected requirement specifications that they should adhere to and strive to satisfy. In the present work a systematic sequence of development phases associated with computer implemented information structures for requirements, functions and systems have been studied at three companies with widely different products and business scenarios. Although individual adaptations are required, the overall processes for requirement decomposition and propagation appear surprisingly similar. To fully exploit the potential of such information systems, many companies would benefit from also including knowledge structures in their product models. Fundamental product and process knowledge often evolves slowly over time, can be gradually upgraded and be reused many times. It also constitutes one of the company's most valuable assets and should be carefully maintained and enhanced. In the work presented here a few different approaches to integrating knowledge structures into the total product information structure have been developed and exemplified for the three companies studied.Copyright (c) 2003 by ASME", "author_names": [ "Staffan Sunnersjo", "Ingvar Rask", "Rafael Amen" ], "corpus_id": 109326413, "doc_id": "109326413", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Requirement Driven Design Processes With Integrated Knowledge Structures", "venue": "", "year": 2003 } ]
Mathematical modeling and simulation of photovoltaic cell using matlab-simulink environment
[ { "abstract": "Photovoltaic power supplied to the utility grid is gaining more and more visibility while the world's powers demand is increases. Growing demand, advancements in semiconductor technology and magnetic materials such as high frequency inductor cores, has a significant impact on PV inverter topologies and their efficiencies, on the improvement of the control circuits on the potential of costs reduction. The user naturally wants to operate the Photovoltaic (PV) array at its highest energy conversion output by continuously utilizing the maximum available solar power of the array. The electrical system PV modules are powered by solar arrays requires special design considerations due to varying nature of the solar power generated resulting from unpredictable and sudden changes in weather conditions which change the solar irradiation level as well as the cell operating temperature. This paper, a mathematical model of a Photovoltaic (PV) cell used matlab simulink environment, is developed and presented. The model is developed using basic circuit equations of the photovoltaic solar cells including the effects of solar irradiation and temperature changes. The main objective is to find the parameters of the nonlinear I V equation by adjusting the curve at three points: open circuit, maximum power, and short circuit. the method finds the best I V equation for the single diode photovoltaic (PV) model including the effect of the series and parallel resistances Key words Photovoltaic system (PV) maximum power, PV array,PV cell", "author_names": [ "J Surya Kumari", "Challa Babu" ], "corpus_id": 59129058, "doc_id": "59129058", "n_citations": 115, "n_key_citations": 4, "score": 1, "title": "Mathematical Modeling and Simulation of Photovoltaic Cell using Matlab Simulink Environment", "venue": "", "year": 2011 }, { "abstract": "Due to scarcity of fossil fuel and increasing demand of power supply, we are forced to utilize the renewable energy resources. Considering easy availability and vast potential, world has turned to solar photovoltaic energy to meet out its ever increasing energy demand. The mathematical modelling and simulation of the photovoltaic system is implemented in the MATLAB/Simulink environment and the same thing is tested and validated using Artificial Intelligent (AI) like ANFIS. This paper presents a scheme for transferring power from photovoltaic (PV) module to a battery using solar charge controller based on buck DC/DC converter. The converter is configured in open loop mode and the same thing is implemented in hardware. The results reveals that the implemented hardware results matches closely with the simulated software results. Due to high initial investment on PV systems and non linearity of PV cell output characteristics counteract its wide commercialization. The PV array has an optimum operating point to generate maximum power at some particular point called maximum power point (MPP) To track this maximum power point and to draw maximum power from PV arrays, MPPT controller is required in a stand alone PV system. Due to the nonlinearity in the output characteristics of PV array, it is very much essential to track the MPPT of the PV array for varying maximum power point due to the insolation variation. In order to track the MPPT conventional controller like PI controller with Incremental conductance algorithm is proposed and simulated. The output of the controller, pulse generated from PWM can switch MOSFET to change the duty cycle of buck DC DC converter. The result reveals that the maximum power point is tracked satisfactorily for varying insolation condition.", "author_names": [ "A Durgadevi", "S Arulselvi" ], "corpus_id": 17923644, "doc_id": "17923644", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "ANFIS Modeling and Experimental Study of Standalone Photovoltaic Battery Charging System", "venue": "", "year": 2012 }, { "abstract": "This paper presents modeling of Photovoltaic (PV) module using MATLAB/Simulink. The model is developed on the basis of mathematical model of the PV module. The PV module of VIKRAM SOLAR PANEL PVELDORA 230 is selected for the experimental and technical data to analyze the developed model. The objective of this paper is to develop a model to simulate the behavior of a photovoltaic cell. Both models are implemented in MATLAB/Simulink. To demonstrate the validity of the model the IV and PV curves results were compared with those provided by the manufacturer.", "author_names": [ "Nisha Sharma", "Dr Fahim Ansari", "Pawan Kr Panday" ], "corpus_id": 14308349, "doc_id": "14308349", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Modeling and Simulation of Photovoltaic Cell Using Matlab Simulink", "venue": "", "year": 2013 }, { "abstract": "Photovoltaic (PV) model is used in a simulation study to validate the system design of a PV system. This paper presents a step by step (detailed modeling) procedure for the simulation of photovoltaic modules with numerical values, using Matlab/Simulink software package. The proposed model is developed based on the mathematical model of the PV module, which is based on that of an elementary PV solar cell employing One diode equivalent circuit. A particular Polycrystalline PV module is selected for the analysis of the developed model. The essential parameters required for modeling the system are taken from datasheets. The output current and power characteristic curves highly depend on some climatic factors such as solar radiation and temperature, are obtained by simulation for the selected module with the output power of 250 W and discussed.", "author_names": [ "Hanane Yatimi", "Elhassan Aroudam" ], "corpus_id": 56368963, "doc_id": "56368963", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Mathematical Modeling and Simulation of Photovoltaic Power Source using Matlab/Simulink", "venue": "", "year": 2016 }, { "abstract": "This study explored different models of PV cell, namely, single diode model and double diode models using MATLAB/Simulink Environment. The output power and current characteristics are analyzed for different solar intensity radiations and temperature variations of PV cell. Simulation results are obtained for different atmospheric and temperature conditions. The simulation results reveal that the double diode model generates maximum power and has a higher efficiency compared to single diode model.", "author_names": [ "C H Hussaian Basha", "C Rani", "R M Brisilla", "Sarah Odofin" ], "corpus_id": 213323964, "doc_id": "213323964", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Mathematical Design and Analysis of Photovoltaic Cell Using MATLAB/Simulink", "venue": "SocProS", "year": 2018 }, { "abstract": "Photovoltaic (PV) array which consists of series and parallel connected modules is the fundamental building block of a photovoltaic energy conversion system. PV array shows nonlinear characteristics and evaluating the operating characteristics under time varying environmental conditions is a too costly and time consuming task. To avoid these hindrances, an elementary and a basic model of PV array were modeled and incorporated to different software involving MATLAB/SIMULINK. Although, these PV models are not appropriate for operation, including hybrid energy network because these systems require pliant tuning of various parameters and cannot be easy to understand. So, this paper describes a step by step method to simulate PV array using MATLAB/SIMULINK. An MSX 64W PV panel has been taken as a base model. The characteristic's curves of PV module are also evaluated at a broad range of environmental circumstances and physical parameters. The effects of partial shading conditions on PV characteristics are also discussed.", "author_names": [ "Nupur Yadav", "D K Sambariya" ], "corpus_id": 53012993, "doc_id": "53012993", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Mathematical Modelling and Simulation of Photovoltaic Module Using MATLAB/SIMULINK", "venue": "2018 9th International Conference on Computing, Communication and Networking Technologies (ICCCNT)", "year": 2018 }, { "abstract": "Purpose The aviation industry has started environment friendly and also conventional energy independent alternative energy dependent designs to reduce negative impacts on the nature and to maintain its future activities in a clear, renewable and sustainable way. One possible solution proposed is solar energy. Solar powered aerial vehicles are seen as key solutions to reduce global warming effects. This study aims to simulate a mathematical model of a solar powered DC motor of an UAV on MATLAB/Simulink environment. Design/methodology/approach Maximum power point tracking (MPPT) is a critical term in photovoltaic (PV) array systems to provide the maximum power output to the related systems under certain conditions. In this paper, one of the popular MPPT techniques, \"Incremental Conductance\" is simulated with solar powered DC motor for an UAV design on MATLAB/Simulink. Findings The cascade structure (PV cell, MPPT, buck converter and DC motor models) is simulated and tested under various irradiance values, and results are compared to the DC motor technical data. As a result of that, mathematical model simulation results are overlapped with motor technical reference values in spite of irradiance changes. Practical implications It is suggested to be used in real time applications for future developments. Originality/value Different from other solar powered DC motor literature works, a solar powered DC motor mathematical model of an UAV is designed and simulated on MATLAB/Simulink environment. To adjust the maximum power output at the solar cell, incremental conductance MPPT technique is preferred and a buck converter structure is connected between MPPT and DC motor mathematical model. It is suggested to be used in solar powered UAV designs for future developments.", "author_names": [ "Eralp Sener", "Irem Turk", "Isil Yazar", "Tahir Hikmet Karakoc" ], "corpus_id": 208845096, "doc_id": "208845096", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Solar powered UAV model on MATLAB/Simulink using incremental conductance MPPT technique", "venue": "Aircraft Engineering and Aerospace Technology", "year": 2019 }, { "abstract": "Rozrobleno imitatsiinu model' mekhanichnoyi komponenti povnistiu diferentsiinogo iemnisnogo MEMS akselerometra v seredovishchi MATLAB/Simulink. Model' daie zmogu modeliuvati peremishchennia robochoyi masi, zminu iemnostei vimiriuval'nikh kondensatoriv chutlivogo elementa, chutlivist' mikrodavacha vid prikladenogo priskorennia, a takozh provoditi chasovii analiz integral'nogo pristroiu na sistemnomu rivni proektuvannia. Kliuchovi slova: Mikroelektromekhanichni sistemi (MEMS) povnistiu diferentsiinii iemnisnii MEMS akselerometer, priskorennia, matematichne modeliuvannia, imitatsiina model' povedinkovii analiz, SAPR, MATLAB/Simulink.", "author_names": [ "A Holovatyy", "Vasyl Teslyuk", "Roman Panchak", "S Koshyrets" ], "corpus_id": 112000917, "doc_id": "112000917", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Mathematical modelling and simulation of the mechanical component of the fully differential capacitive mems accelerometer using matlab/simulink environment", "venue": "", "year": 2015 }, { "abstract": "This work presents a modeling and simulation of a photovoltaic generator by the Matlab Simulink environment where we have prepared a standard block diagram using the basic mathematical symbols existing in the Simulink library to simulate all possible connection cases either in Series, parallel or mixed assembly of photovoltaic cells, modules, panels or fields to produce an electrical power according to our need. Thanks to this simulation block, ElWahat pour les Recherches et les EtudesVol.10 ndeg1 (2017) 1 19 A. Bahri 2 we have done a practical comparison of the results of the photovoltaic plant at Oued Nechou in Ghardaia where we compared the results obtained by the practical data with those presented by the manufacturer of this PV plant, A point of view influence of the temperature and the sunlight on the characteristics of the PV panels as we found results in agreement with those displayed by the manufacturer of this PV plant as well as with the data recorded at the site level concerned on 24/04/2016.", "author_names": [ "Ahmed Zakaria Bahri" ], "corpus_id": 196139410, "doc_id": "196139410", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Modelisation et simulation d'un generateur photovoltaique sous Matlab/Simulink Etude pratique site Oued Nechou a Ghardaia", "venue": "", "year": 2017 }, { "abstract": "Abstract The Physical modeling is not much efficient so the analysis is done through a Mathematical modeling. In this paper modeling of Photovoltaic cell is done in numerical real life simulation through a single diode Photovoltaic cell. A 36 W PV module designed through MATLAB/Simulink environment. Also, designed the SR 12 module PEMFC with 500 W rated powers. Different characteristics of these modules were examined under different states. Main determination of this research is to use this power generation sources for further analysis of hybrid generation system with renewable energy sources.", "author_names": [ "Bhagchand D Thavrani", "Hardik B Patel", "Ketan Bariya" ], "corpus_id": 139205849, "doc_id": "139205849", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Mathematical Modeling of PEMFC and Photovoltaic Module", "venue": "", "year": 2016 } ]
100 GHz Plasmonic Photodetector
[ { "abstract": "Photodetectors compatible with CMOS technology have shown great potential in implementing active silicon photonics circuits, yet current technologies are facing fundamental bandwidth limitations. Here, we propose and experimentally demonstrate for the first time a plasmonic photodetector achieving simultaneously record high bandwidth beyond 100 GHz, an internal quantum efficiency of 36% and low footprint. High speed data reception at 72 Gbit/s is demonstrated. Such superior performance is attributed to the subwavelength confinement of the optical energy in a photoconductive based plasmonic germanium waveguide detector that enables shortest drift paths for photogenerated carriers and a very small resistance capacitance product. In addition, the combination of plasmonic structures with absorbing semiconductors enables efficient and highest speed photodetection. The proposed scheme may pave the way for a cost efficient CMOS compatible and low temperature fabricated photodetector solution for photodetection b.", "author_names": [ "Yannick Salamin", "Ping Ma", "Benedikt Baeuerle", "Alexandros Emboras", "Yuriy Fedoryshyn", "Wolfgang Heni", "Bojun Cheng", "Arne Josten", "Juerg Leuthold" ], "corpus_id": 125470445, "doc_id": "125470445", "n_citations": 91, "n_key_citations": 4, "score": 1, "title": "100 GHz Plasmonic Photodetector", "venue": "", "year": 2018 }, { "abstract": "A compact and high speed integrated photoconductive plasmonic photodetector is demonstrated. The proposed photodetector features a bandwidth beyond 100 GHz with an internal quantum efficiency of 36 around 1310 nm.", "author_names": [ "Ping Ma", "Yannick Salamin", "Benedikt Baeuerle", "Alexandros Emboras", "Yuriy Fedoryshyn", "Wolfgang Heni", "Bojun Cheng", "Arne Josten", "Juerg Leuthold" ], "corpus_id": 51971604, "doc_id": "51971604", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "100 GHz Photoconductive Plasmonic Germanium Detector", "venue": "2018 Conference on Lasers and Electro Optics (CLEO)", "year": 2018 }, { "abstract": "We demonstrate a novel, ultra compact, waveguide integrated, and plasmonically enhanced graphene photodetector featuring a responsivity of 0.5 A/W and a bandwidth exceeding 110 GHz. We show for the first time 100 GBd data reception with a graphene based device.", "author_names": [ "Ping Ma", "Yannick Salamin", "Benedikt Baeuerle", "Arne Josten", "Wolfgang Heni", "Yuriy Fedoryshyn", "Alexandros Emboras", "Juerg Leuthold" ], "corpus_id": 53437259, "doc_id": "53437259", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "100 GBd Ultra Compact Plasmonic Graphene Photodetector", "venue": "2018 European Conference on Optical Communication (ECOC)", "year": 2018 }, { "abstract": "We investigate a waveguide integrated plasmonic graphene photodetector operating based on the hot carrier photo bolometric effect, which is characterized simultaneously by high responsivity on the scale of hundreds of A/W and high speed on the scale of 100's of GHz that is limited only by the product of the electronic heat capacitance and thermal resistance. We develop a theory of the bolometric effect originating from the band nonparabolicity of graphene and estimate responsivity due to the bolometric effect, which is shown to significantly surpass the responsivity of the coexisting photoconductive effect, thus convincingly demonstrating the dominance of the bolometric effect. Based on the theory, we propose a novel detector configuration based on a hybrid waveguide that allows for efficient absorption in graphene over a short distance and subsequently a large change of conductivity. The results demonstrate the potential of graphene for high speed communication systems.", "author_names": [ "Jacek Gosciniak", "Jacob B Khurgin" ], "corpus_id": 211076356, "doc_id": "211076356", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "On Chip Ultrafast Plasmonic Graphene Hot Electron Bolometric Photodetector", "venue": "ACS omega", "year": 2020 }, { "abstract": "Here we propose an original waveguide integrated plasmonic Schottky photodetector that takes full advantage of a thin metal stripe embedded entirely into a semiconductor. The photodetector is based on the long range dielectric loaded surface plasmon polariton waveguide with a metal stripe deposited on top of a semiconductor rib and covered by another semiconductor. As the metal stripe is entirely surrounded by semiconductor, all hot electrons with appropriate k vectors can participate in transitions that highly enhances the electron transfer, and consequently the internal quantum efficiency. In addition, a high coupling efficiency from the photonic waveguide to the photodetector is simulated exceeding 90 which enhances the external quantum efficiency. Calculations show that a responsivity exceeding 0.5 A/W can be achieved at telecom wavelength of 1550 nm and the bandwidth can exceed 100 GHz. Furthermore, it is shown that titanium nitride is a perfect material for the photodetector as it provides a low Fermi energy and long electron mean free path that enhance the hot electron transfer to the semiconductor. In addition, it shows reasonable metallic behavior and CMOS compatibility. Measurements showed that the Schottky barrier height between titanium nitride and p doped silicon reaches 0.69 0.70 eV that matches the optimum signal to noise ratio operation calculated at 0.697 eV.", "author_names": [ "Jacek Gosciniak", "Fatih Bilge Atar", "Brian Corbett", "Mahmoud S Rasras" ], "corpus_id": 115153431, "doc_id": "115153431", "n_citations": 23, "n_key_citations": 1, "score": 0, "title": "Plasmonic Schottky photodetector with metal stripe embedded into semiconductor and with a CMOS compatible titanium nitride", "venue": "Scientific Reports", "year": 2019 }, { "abstract": "We investigate a waveguide integrated plasmonic graphene photodetector operating based on the hot carrier either photo thermoelectric or photo bolometric effect, which is characterized simultaneously by high responsivity on the scale of hundreds of A/W and high speed on the scale of 100's of GHz. The proposed detector configuration is based on a hybrid waveguide that allows for efficient absorption in graphene over a short distance and subsequently a large change of conductivity. The results demonstrate the potential of graphene for high speed communication systems.", "author_names": [ "Jacek Gosciniak", "Jacob B Khurgin" ], "corpus_id": 229534355, "doc_id": "229534355", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "On chip ultrafast plasmonic graphene photodetectors", "venue": "", "year": 2020 }, { "abstract": "A fast silicon graphene hybrid plasmonic waveguide photodetectors beyond 1.55 \\mu}m is proposed and realized by introducing an ultra thin wide silicon on insulator ridge core region with a narrow metal cap. With this novel design, the light absorption in graphene is enhanced while the metal absorption loss is reduced simultaneously, which helps greatly improve the responsivity as well as shorten the absorption region for achieving fast responses. Furthermore, metal graphene metal sandwiched electrodes are introduced to reduce the metal graphene contact resistance, which is also helpful for improving the response speed. When the photodetector operates at 2 \\mu}m, the measured 3dB bandwidth is >20 GHz (which is limited by the experimental setup) while the 3dB bandwith calculated from the equivalent circuit with the parameters extracted from the measured S11 is as high as ~100 GHz. To the best of our knowledge, it is the first time to report the waveguide photodetector at 2 \\mu}m with a 3dB bandwidth over 20 GHz. Besides, the present photodetectors also work very well at 1.55 \\mu}m. The measured responsivity is about 0.4 A/W under a bias voltage of 0.3 V for an optical power of 0.16 mW, while the measured 3dB bandwidth is over 40 GHz (limited by the test setup) and the 3 dB bandwidth estimated from the equivalent circuit is also as high as ~100 GHz, which is one of the best results reported for silicon graphene photodetectors at 1.55 \\mu}m.", "author_names": [ "Jingshu Guo", "Jiang Li", "Chaoyue Liu", "Yanlong Yin", "Wenhui Wang", "Zhenhua Ni", "Zhilei Fu", "Hui Yu", "Yang Xu", "Yaocheng Shi", "Yungui Ma", "Shiming Gao", "Limin Tong", "Daoxin Dai" ], "corpus_id": 198967899, "doc_id": "198967899", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "High performance silicon graphene hybrid plasmonic waveguide photodetectors beyond 1.55 \\mu}m", "venue": "", "year": 2019 }, { "abstract": "Abstract In recent years, the data traffic has grown exponentially and the forecasts indicate a huge market that could be addressed by optoelectronics. However, the processing capacity, space, and energy consumption of the available technology is a serious bottleneck for the exploitation of these markets. Graphene material is a new candidate using in optoelectronics' devices such as photodetector. The responsivity of Graphene photodetectors depends critically on the elevated temperature of the electronic subsystem upon photoexcitation. We performed in this study a multi layer Graphene/InGaAs /InAlAs/InAs Photodetector PIN simulation with Atlas under Silvaco tcad Tools using Graphene and high electronmobility III V materials. Our devices exhibit 100 GHz bandwidth with 40 ps transient reponse, 5.8 mA of photocurrent, high responsivity with value of (2.7 x 10 7 A/w) and a suitable efficiency e of 95% with reasonable rejection ration of Iilumination/Idark of 2 order of magnitude.", "author_names": [ "M Khaouani", "Hichem Bencherif", "Zakarya Kourdi", "Lakhdar Dehimi", "A Hamdoune", "Mohamed Amir Abdi" ], "corpus_id": 229498897, "doc_id": "229498897", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "An ultrafast multi layer Graphene/InGaAs/InAlAs/InAs P I N photodetector with 100 GHz bandwidth", "venue": "", "year": 2020 }, { "abstract": "We designed and fabricated a zero bias operational uni travelling carrier photodetector for high outputs, and achieved a photocurrent saturation of 7 mA and an output saturation of 1 dBm at 110 GHz at 0 V. Furthermore, we observed that the output performance at 0 V could be improved by reducing the thickness of the InP layer to 70% of that in the original design. The results of the simulation showed that the photocurrent and RF output power were nearly doubled in the 100 GHz range. The device design and the experimental results have been discussed herein.", "author_names": [ "Toshimasa Umezawa", "Atsushi Matsumoto", "Atsushi Kanno", "Naokatsu Yamamoto", "Tetsuya Kawanishi" ], "corpus_id": 212635779, "doc_id": "212635779", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Investigation of 100 GHz Output Power Performance in Uni travelling Carrier Photodetector under Zero bias Condition", "venue": "2019 PhotonIcs Electromagnetics Research Symposium Spring (PIERS Spring)", "year": 2019 }, { "abstract": "As bit rates of optical interconnects increase, a large amount of complicated signal conditioning is needed to compensate for the insufficient bandwidth of current modulators. In this paper, we evaluate the reduced equalization requirements of high bandwidth plasmonic modulators in short reach transmission experiments. It is shown that transmission of 100 Gbit/s non return to zero (NRZ) and 112 Gbit/s pulse amplitude modulation 4 over 1 km and 2 km distance is possible without any receiver equalization. At higher bit rates, such as 120 Gbit/s NRZ, data transmission is demonstrated over 500 m with reduced receiver equalization requirements. Transmission up to 200 Gbit/s over 1 km is also shown with more complex receiver equalization. The reduced complexity of the receiver digital signal processing is attributed to a flat frequency response of at least 108 GHz of the plasmonic modulators. All single wavelength transmissions have been performed at 1540 nm in standard single mode fiber.", "author_names": [ "Benedikt Baeuerle", "Wolfgang Heni", "Claudia Hoessbacher", "Yuriy Fedoryshyn", "Arne Josten", "Christian Haffner", "Tatsuhiko Watanabe", "Christopher Uhl", "Horst Hettrich", "Delwin L Elder", "Larry R Dalton", "Michael Moller", "Juerg Leuthold" ], "corpus_id": 116531099, "doc_id": "116531099", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Reduced Equalization Needs of 100 GHz Bandwidth Plasmonic Modulators", "venue": "Journal of Lightwave Technology", "year": 2019 } ]
Post-linearization of cascode CMOS low noise amplifier using folded PMOS IMD sinker
[ { "abstract": "A post linearization technique for the cascode complementary metal oxide semiconductor (CMOS) low noise amplifier (LNA) is presented. The proposed method uses an additional folded cascode positive channel metal oxide semiconductor field effect transistor for sinking the third order intermodulation distortion (IMD3) current generated by the common source stage, while minimizing the degradation of gain and noise figure. This technique is applied to enhance the linearity of CMOS LNA using 0.18 /spl mu/m technology. The LNA achieved +13.3 dBm IIP3 with 12.8 dB gain, 1.4dB NF at 2GHz consuming 8mA from a 1.8 V supply.", "author_names": [ "Tae-Sung Kim", "Byung-Sung Kim" ], "corpus_id": 108520751, "doc_id": "108520751", "n_citations": 69, "n_key_citations": 4, "score": 1, "title": "Post linearization of cascode CMOS low noise amplifier using folded PMOS IMD sinker", "venue": "", "year": 2006 }, { "abstract": "A post linearization technique for the cascode complementary metal oxide semiconductor (CMOS) low noise amplifier (LNA) is presented. The proposed method uses an additional folded cascode positive channel metal oxide semiconductor field effect transistor for sinking the third order intermodulation distortion (IMD3) current generated by the common source stage, while minimizing the degradation of gain and noise figure. This technique is applied to enhance the linearity of CMOS LNA using 0.18 /spl mu/m technology. The LNA achieved +13.3 dBm IIP3 with 12.8 dB gain, 1.4dB NF at 2GHz consuming 8mA from a 1.8 V supply.", "author_names": [ "" ], "corpus_id": 2047159, "doc_id": "2047159", "n_citations": 18, "n_key_citations": 2, "score": 0, "title": "Post linearization of cascode CMOS low noise amplifier using folded PMOS IMD sinker", "venue": "IEEE Microwave and Wireless Components Letters", "year": 2006 }, { "abstract": "A highly linear 5.5 GHz low noise amplifier (LNA) has been designed exploiting source inductive degeneration topology by using post distortion linearization techniques in 0.18 m CMOS technology. This technique improves the input third order intercept point (IIP_{3}(IIP3) of a low noise amplifier. For enhancing the linearity, this technique used a diode connected MOSFET as IMD sinker and forward body biased which is done in cadence tool. The proposed low noise amplifier achieves high $IIP_{3}$IIP3 by using two transistors, main and auxiliary transistors. Also source inductive degeneration topology is employed in the proposed LNA to optimize the noise figure (NF) and $S_{11}$S11 at high frequency. In order to reduce power consumption and threshold voltage, Forward Body Biased technique was implemented. In this paper, the first section discusses the most widely used eight linearization techniques and in the second section, the proposed circuit is represented along with its employed topology, techniques and the simulated results. The proposed LNA achieves a simulated third order input intercept (IIP_{3}(IIP3) of 9.20 dBm while consuming 10.8 mW from a power supply of 1.8 V. it also exhibits a measured gain of 11.34 dB and NF, NF of 2.33 dB.", "author_names": [ "Ram Kumar", "Anandini Devi", "Abahan Sarkar", "Fazal Ahmed Talukdar" ], "corpus_id": 107301210, "doc_id": "107301210", "n_citations": 8, "n_key_citations": 1, "score": 0, "title": "Design of 5.5 GHz linear low noise amplifier using post distortion technique with body biasing", "venue": "", "year": 2016 }, { "abstract": "A fully integrated 5.5GHz high linearity low noise amplifler (LNA) using post linearization technique, implemented in a 0.18\"m RF CMOS technology, is demonstrated. The proposed technique adopts an additional folded diode with a parallel RC circuit as an intermodulation distortion (IMD) sinker. The proposed LNA not only achieves high linearity, but also minimizes the degradation of gain, noise flgure (NF) and power consumption. The LNA achieves an input third order intercept point (IIP3) of +8:33dBm, a power gain of 10.02dB, and a NF of 3.05dB at 5.5GHz biased at 6mA from a 1.8V power supply.", "author_names": [ "Chieh-Pin Chang", "Wei-Chih Chien", "Chun-Chi Su", "Yeong-Her Wang", "Ja-Hao Chen" ], "corpus_id": 15508630, "doc_id": "15508630", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Linearity improvement of cascode CMOS LNA using a diode connected NMOS transistor with a parallel RC circuit", "venue": "", "year": 2010 }, { "abstract": "A high gain CMOS Low Noise Amplifier (LNA) for 866 MHz RFID reader has been proposed and simulated in 0.18 mm CMOS technology. A new energy efficient technique along with the current bleeding PMOS devices has been used to reduce the leakage power of the RF signal and increase the gain of the proposed LNA design. Furthermore, the folded cascode with a combination of the partial source degeneration (PSD) is improved; and the current and boosting inductor are reused to enhance the gain and linearity of the proposed design. The simulation results show that the proposed LNA design outperforms the conventional fold cascode LNA in terms of gain (S21) and Noise Figure (NF) The proposed LNA achieves a forward gain of 24.8 dB with a NF of 0.38 dB with 10.6mW drawn from a 1.2V source supply; and a high linearity Input Third Order Intercept Point (IIP3) of 3dBm. Keywords 0.18mm CMOS technology, Boosting inductors, Gain, Linearity, Partial source degeneration PSD, Radio frequency identification RFID.", "author_names": [ "Zaid Albataineh", "Yazan Hamadeh", "Jafar Moheidat", "Ahmad Dagamseh", "Idrees S Al-Kofahi", "Mohammed O Alsumady" ], "corpus_id": 127993010, "doc_id": "127993010", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "A High Gain Low Noise Amplifier for RFID Front Ends Reader", "venue": "", "year": 2017 }, { "abstract": "In this paper presents a optimization of linearity of low noise amplifier by using post linearization techniques. in this technique we have used diode connected mosfet as IMD sinker also used interstage matching for gain enhancement and reducing the effect of nonlinearity in common gate stage of cascode amplifier, this has done by using UMC .18um CMOS Technology in cadence tool. We got gain 14dB, noise figure 2.1dB, IIP3 3.19dBm with power supply of 1.8v, and power consumption is 10.8mw.", "author_names": [ "Ram Kumar", "Jitendra Kumar Mishra" ], "corpus_id": 16453273, "doc_id": "16453273", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A low noise amplifier with improved linearity and high gain", "venue": "", "year": 2013 }, { "abstract": "A 5GHz Low Noise Amplifier (LNA) is presented using the folded cascode topology which is suitable for low voltage Radio Frequency Identification (RFID) applications. It employs both NMOS and PMOS devices to reduce the required supply voltage to less than 1V. The circuit is fully integrated on chip, with inductors implemented using stacked spirals to save space. It is experimentally demonstrated in 0.18mm CMOS and performs particularly well at 5GHz, with the noise figure being below 3dB. The gain and input 1dB compression point exceed 12dB and 11.5dBm respectively, while the input return loss is better than 20dB. The LNA has an active footprint of only 575mm by 525mm, and consumes less than 10mW from a 1V supply.", "author_names": [ "Ahmed M El-Gabaly", "Carlos E Saavedra" ], "corpus_id": 14869179, "doc_id": "14869179", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A Low Voltage Fully Integrated 5 GHz Low Noise Amplifier in 0 18 m m CMOS", "venue": "", "year": 2008 }, { "abstract": "This work describes a 0.5 mm CMOS implementation of a Folded Cascode OTA designed for minimum Input Referred Noise for non implantable EEG SoC arrays. It is also described a small area PID feedback network using a high resistive pMOS pseudo resistor and small integration capacitances for programmable gain control throughout parasitic insensitive nMOS switches. Simulation results show that it achieves about 2.2 mVrms of input referred noise for 6 mA of total current at 1.8 V supply voltage. The circuit provides a NEF of 4.55 within a 1.96 kHz bandwidth and midband gain of 40.22 dB.", "author_names": [ "Odilon de Oliveira Dutra", "T Pimenta" ], "corpus_id": 18595841, "doc_id": "18595841", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Low Power Low Noise Neural Amplifier with Adjustable Gain", "venue": "2012 IEEE Ninth Electronics, Robotics and Automotive Mechanics Conference", "year": 2012 }, { "abstract": "High resolution high speed comparators are one of the main cores in the implementation of the high performance systems, such as ADCs. Two comparators are presented in this paper where both of the structures are suitable for high speed, low noise and accurate applications. The comparators are designed, based on the positive feedback structure of two back to back inverters. An improved rail to rail folded cascode amplifier with an active bias circuit is utilized for the first architecture, in which the structure of the comparator is rearranged appropriate to the running comparison phase. Distinguished by its novel data reception style, a new comparator is proposed in the next circuit. In this structure, the hot n well concept is considered for the PMOS transistors of the positive feedback latch. Applying the inputs to the bulks of the mentioned PMOS devices, isolates the regenerative outputs from the input signals; hence, a sizable attenuation in the kickback noise value is resulted. Merging the reset, evaluation and latch sequences makes it possible to decrease the comparison duration. Both of the proposed comparators of this paper benefits from this excellence, therefore an intensive increase is observed in their comparison speed. In order to confirm the performance accuracy of the circuits in various terms, multiple simulations are performed in all process corners, using HSPICE (level49) with a standard 0.35mm CMOS process and the power supply of 3.3V. VDD noise of 300mVp p and alterations in temperature are also included in the simulation conditions. The simulation results confirm recognition of a differential input with 2mV pick to pick amplitude at as high a clock frequency as 800MHz with power consumption about 2.6mW for the first circuit and a 1mV differential input with update rate of 1GHz and power consumption about 1.6mW for the low noise structure of the second comparator. According to the layout pattern, an active area of 55mm x 13mm and 24mm x 15mm is occupied by the improved folded cascode comparator and the proposed novel structure respectively.", "author_names": [ "Ali Baradaran Rezaeii", "Obalit Shino", "Tohid Moradi" ], "corpus_id": 18968233, "doc_id": "18968233", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Low Kickback Noise Preamplifier Latched Comparators Designed for High Speed Accurate ADCs", "venue": "", "year": 2015 }, { "abstract": "The charge sensitive amplifier (CSA) unit is used in processing signals from capacitive sensors such as photo detectors, pressure sensors, particle and X ray detectors. Next generation front end ASICs will use advanced CMOS and BiCMOS technologies including MOSFETs with minimum channel length (of 45 nm and below) and SiGe Heterojunction Bipolar Transistors (HBTs) The most common CSA architecture employed either in CMOS or BiCMOS implementations is the folded cascode amplifying topology due to its low noise performance, the high gain capability and its gain insensitivity to the detector capacitance variations [1] [4] While noise optimization methodologies have been proposed for both kinds of CSAs (CMOS or BiCMOS) and plenty of CSA designs were so far presented [1] [5] none extended research has been performed about the suitability of each process in relation to the application specifications such as detector capacitance, power consumption, noise performance and speed. In addition, other important issues like the main noise contributors and the radiation hardness capability are also not have been extensively addressed. Particularly, four equivalent folded cascode amplifying topologies were designed. The primary concern was the examination of devices noise contribution, firstly the input transitor and cascoded one and secondary the reset device noise contribution. The four structures were: a) nMOS as the input and pMOS as cascode, b) pMOS as input, nMOS as cascode, c) npn BJT as input, pMOS as cascode and d) pMOS as input and npn BJT as cascode. To further isolate these noise contributors, ideal bias current sources and output buffer were used, in all four designs. Feedback was implemented using a capacitance in parallel with a large reset resistor. The structures were designed using specific noise optimization criteria design methodologies [1] [5] [6] in two respective processes commercially available by Austria Mikro Systeme (AMS) the 0.35mm CMOS process (2P/3M 3.3/5V) and the 0.35mm SiGe BiCMOS process (2P/3M 3.3/5V) All four folded cascode topologies are depicted in figure 1.", "author_names": [ "Thomas Noulis", "George Fikos", "Stylianos Siskos", "Gerard Sarrabayrouse" ], "corpus_id": 114945492, "doc_id": "114945492", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Folded Cascode Amplifying Structure Evaluation in terms of the used IC process in Radiation Detection Front End Applications", "venue": "", "year": 2009 } ]
Modern power electronics and AC drives
[ { "abstract": "(NOTE: Each chapter begins with an Introduction and concludes with a Summary and References. Preface. List of Principal Symbols. 1. Power Semiconductor Devices. Diodes. Thyristors. Triacs. Gate Turn Off Thyristors (GTOs) Bipolar Power or Junction Transistors (BPTs or BJTs) Power MOSFETs. Static Induction Transistors (SITs) Insulated Gate Bipolar Transistors (IGBTs) MOS Controlled Thyristors (MCTs) Integrated Gate Commutated Thyristors (IGCTs) Large Band Gap Materials for Devices. Power Integrated Circuits (PICs) 2. AC Machines for Drives. Induction Machines. Synchronous Machines. Variable Reluctance Machine (VRM) 3. Diodes and Phase Controlled Converters. Diode Rectifiers. Thyristor Converters. Converter Control. EMI and Line Power Quality Problems. 4. Cycloconverters. Phase Controlled Cycloconverters. Matrix Converters. High Frequency Cycloconverters. 5. Voltage Fed Converters. Single Phase Inverters. Three Phase Bridge Inverters. Multi Stepped Inverters. Pulse Width Modulation Techniques. Three Level Inverters. Hard Switching Effects. Resonant Inverters. Soft Switched Inverters. Dynamic and Regenerative Drive Braking. PWM Rectifiers. Static VAR Compensators and Active Harmonic Filters. Introduction to Simulation MATLAB/SIMULINK. 6. Current Fed Converters. General Operation of a Six Step Thyristor Inverter. Load Commutated Inverters. Force Commutated Inverters. Harmonic Heating and Torque Pulsation. Multi Stepped Inverters. Inverters with Self Commutated Devices. Current Fed vs Voltage Fed Converters. 7. Induction Motor Slip Power Recovery Drives. Doubly Fed Machine Speed Control by Rotor Rheostat. Static Kramer Drive. Static Scherius Drive. 8. Control and Estimation of Induction Motor Drives. Induction Motor Control with Small Signal Model. Scalar Control. Vector or Field Oriented Control. Sensorless Vector Control. Direct Torque and Flux Control (DTC) Adaptive Control. Self Commissioning of Drive. 9. Control and Estimation of Synchronous Motor Drives. Sinusoidal SPM Machine Drives. Synchronous Reluctance Machine Drives. Sinusoidal IPM Machine Drives. Trapezoidal SPM Machine Drives. Wound Field Synchronous Machine Drives. Sensorless Control. Switched Reluctance Motor (SRM) Drives. 10. Expert System Principles and Applications. Expert System Principles. Expert System Shell. Design Methodology. Applications. Glossary. 11. Fuzzy Logic Principles and Applications. Fuzzy Sets. Fuzzy System. Fuzzy Control. General Design Methodology. Applications. Fuzzy Logic Toolbox. Glossary. 12. Neural Network Principles and Applications. The Structure of a Neuron. Artificial Neural Network. Other Networks. Neural Network in Identification and Control. General Design Methodology. Applications. Neuro Fuzzy Systems. Demo Program with Neural Network Toolbox. Glossary. Index.", "author_names": [ "Bimal K Bose" ], "corpus_id": 109000242, "doc_id": "109000242", "n_citations": 3193, "n_key_citations": 296, "score": 1, "title": "Modern Power Electronics and AC Drives", "venue": "", "year": 2001 }, { "abstract": "Electrically propelled ships gained popularity by the early 20th century, with the rapid development of submarines and mediumcapacity container ships, mainly using dc motors [1] Synchronous ac motors have since been employed for naval propulsion systems, but due to the restricted operation of the available power electronic devices at that time, these configurations were too expensive and unreliable, and they featured poor performance in terms of speed and torque control [2] Improvements in power electronics devices and drive control schemes as well as the development of high efficiency multiphase induction and synchronous motors have pushed the advancement of electric ship propulsion systems and applications [3] [7]", "author_names": [ "Carlos A Reusser", "Hector A Young", "Joel R Perez Osses", "Marcelo A Perez", "Oliver Simmonds" ], "corpus_id": 229358380, "doc_id": "229358380", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Power Electronics and Drives: Applications to Modern Ship Propulsion Systems", "venue": "IEEE Industrial Electronics Magazine", "year": 2020 }, { "abstract": "Modern electric drives are generally driven by voltage source inverters. With the aim of reducing size and losses, switching speed of modern power electronic devices is steadily increasing. At the same time, it can be observed that operation under repetitive fast voltage transitions is reducing reliability and lifetime of motor insulation due to the additional stress. Available data for allowable voltage pulse stress in insulation material is usually limited to voltage pulses having rise time below 300ns and dv/dt below several kV/us. With the introduction of wide bandgap power electronic devices, dv/dt will be significantly increased leaving the question about the impact on resulting insulation life time. In this paper insulation life time tests are presented under operating conditions similar to medium voltage SiC technology. Reversible and irreversible effects within the material are identified and their connection to switching speed and pulse voltage magnitude shown.", "author_names": [ "Artan Qerkini", "Markus A Vogelsberger", "P Macheiner", "Werner Grubelnik", "Hans Ertl", "Thomas M Wolbank" ], "corpus_id": 204701581, "doc_id": "204701581", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Estimating the Impact of Pulse Voltage Stress Caused by Modern Power Electronics Technology on Machine Winding Insulation Material", "venue": "2019 IEEE 12th International Symposium on Diagnostics for Electrical Machines, Power Electronics and Drives (SDEMPED)", "year": 2019 }, { "abstract": "On May 1, 1988, when the ICE/V high speed experimental train of the German Federal Railways (DB) reached the world record speed of 406.9 km/h, it was the first time that the public at large was presented with the future train in high speed rail traffic. The electric traction equipment of such a forward looking means of traffic must logically represent the latest state of the art. Two development trends in particular characterize the technology. The first is the use of microprocessors for the complete control of the traction system and the second is the use of GTO thyristors for the converters. Siemens innovated the drive system taken from the class BR 120 locomotive of DB for the ICE/V by the development of a microcomputer traction control and a GTO converter. The microcomputer traction control is used for all 82 series power cars, the GTO converters will be provided for the second half of the series power cars.", "author_names": [ "K Klausecker" ], "corpus_id": 109245470, "doc_id": "109245470", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Modern control and power electronics for the AC drives of the German high speed train ICE", "venue": "", "year": 1989 }, { "abstract": "Speed control of electric motors in industrial sector is advancing day by day. The use of power electronic devices in motor drives creates efficient speed control with reduced cost. This paper reviewed the advancement in industrial drives and control from its beginning to the modern drive technology. The paper deals with power semi conductor devices, converter circuits, motor drives and various speed control techniques in the order of their advancement.", "author_names": [ "Eldho Jacob Joy", "Lakshmi Unnikrishnan" ], "corpus_id": 112016108, "doc_id": "112016108", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A Brief History of Power Electronics and Drives", "venue": "", "year": 2014 }, { "abstract": "", "author_names": [ "K Huemmer" ], "corpus_id": 114468815, "doc_id": "114468815", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Modern control and power electronics for the AC drives of the German high speed train ice", "venue": "", "year": 1989 }, { "abstract": "Due to the increased switching speed and switching frequency of wide bandgap (WBG) device based power electronics, the common mode (CM) electromagnetic interference (EMI) noise issue has been exacerbated in the modern motor drive system. Understanding the high frequency impedance of an electric motor is critical in analyzing and mitigating the CM EMI issues. It is also essential to find the dominant parasitic capacitances within the electric machine, which serve as the primary motor to ground CM current paths. This paper investigates the impact of two different winding topologies, namely circumferential and toroidal windings, on the high frequency machine impedance. The geometry of two different windings is analyzed, and motor to ground capacitive coupling paths are identified. Two high frequency per phase motor impedance models are developed, and circuit parameters are extracted from the measured CM and differential mode motor impedance data. The influence of the high switching speed of SiC MOSFET on CM voltage is identified. The CM motor current is estimated under different switching speeds and different high frequency motor impedance models using simulation.", "author_names": [ "Sangwhee Lee", "Mingda Liu", "Woongkul Lee", "Bulent Sarlioglu" ], "corpus_id": 226293906, "doc_id": "226293906", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Comparison of High Frequency Impedance of AC Machines with Circumferential and Toroidal Winding Topologies for SiC MOSFET Machine Drives", "venue": "2020 IEEE Energy Conversion Congress and Exposition (ECCE)", "year": 2020 }, { "abstract": "This Special Section is aimed to research academics and practicing engineers of the industrial electronics and industrial informatics communities to present their most recent findings related to digital control systems in power electronics. It is our pleasure to present this third part of the Special Section on Digital Control Systems in Power Electronics and Drives. The first part was already published in the IEEE TRANSACTIONS ON INDUSTRIAL INFORMATICS in August 2012. The second part was published in the IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS in February 2013. Now, we present the third and final part of this Special Section where more than 60 papers will be published. This Special Section presents to the power electronics community the most recent advances with topics such as the following: Modern digital control strategies and algorithms; Modulation methods; Advances in hardware implementation: FPGA, DSP, microcontrollers, etc. Application to all type of topologies in power electronics; Application to all type of AC drives; and Other applications like renewable energies and smart grids, transportation, mining, pulp and paper, etc.", "author_names": [ "Jose R Rodriguez", "Marian P Kazmierkowski", "Jose R Espinoza", "Pericle Zanchetta", "Marco E Rivera" ], "corpus_id": 28710778, "doc_id": "28710778", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Guest Editorial Special Section on Digital Control Systems in Power Electronics and Electrical Drives Part III", "venue": "IEEE Trans. Ind. Informatics", "year": 2013 }, { "abstract": "The field of electrical engineering is generally segmented into three major areas such that:electronics, power and control. Power electronics is a combination of these three areas. The advent of power semiconductor devices, thyristors in 1957, has been an exciting breakthrough in the art of electric power conversion and its control. In a modern power electronic equipment, there are essentially two types of semiconductor elements: the power semiconductors that can be considered as the muscle of the equipment, and the microelectronic control chips that provide the power to the brain. The DC motor are used extensively in adjustable speed drives and position control applications. Their speeds below base speed can be controlled by armature voltage control. Speeds above base speed are obtained by field flux control. As speed control methods for DC motors are simpler and less expensive than those for ac motors, dc motors are preferred wide speed control range is required. The dc motors used in conjunction with power electronic converters are dc separately excited motors or dc series motors. Depending upon the type of ac source or the method of voltage control, dc drives are classified as under: 1. Single phase dc drives 2. Three phase dc drives 3. Chopper drives.", "author_names": [ "Durgesh Kumar Meshram" ], "corpus_id": 195729796, "doc_id": "195729796", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Power Electronics for Drives and Generators", "venue": "", "year": 2014 }, { "abstract": "This paper presents the power electronics advancement in electric traction drives. In this paper the power electronics traction transformer and multilevel converter are used to improve the performance of electric traction dives. In this paper power electronics devices are used with the traction drives so that the harmonics developed after inversion operation can be reduced using multilevel converter. The main advantage of multilevel converter kind of topology is that it can generate almost perfect current or voltage waveforms, because it is modulated by amplitude instead of pulse width.In this paper introduction to power supply used in electric traction and medium frequency transformers using cycloconverters are used to reduce the frequency of the AC supply used in electric traction. Combining modern high power semiconductor devices with constantly improving magnetic materials opens up the possibility to replace bulky low frequency transformers with a new medium voltage medium frequency conversion structure. This paper also discussed the power quality improvement in electric traction drives using power electronics devices. In this paper there is a discussion of the replacement of conventional pantographs by using unconventional current collection from a contact line for electric traction vehicles.", "author_names": [ "Gaurav Kumar Mishra" ], "corpus_id": 110814009, "doc_id": "110814009", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Power Electronics advancement in Electric Traction Drives An Overview", "venue": "", "year": 2014 } ]
Ultrastrong coupling between light and matter
[ { "abstract": "Light matter coupling with strength comparable to the bare transition frequencies of the system is called ultrastrong. This Review surveys how experiments have realized ultrastrong coupling in the past decade, the new phenomena predicted in this regime and the applications it enables.AbstractUltrastrong coupling between light and matter has, in the past decade, transitioned from a theoretical idea to an experimental reality. It is a new regime of quantum light matter interaction, which goes beyond weak and strong coupling to make the coupling strength comparable to the transition frequencies in the system. The achievement of weak and strong coupling has led to increased control of quantum systems and to applications such as lasers, quantum sensing, and quantum information processing. Here we review the theory of quantum systems with ultrastrong coupling, discussing entangled ground states with virtual excitations, new avenues for nonlinear optics, and connections to several important physical models. We also overview the multitude of experimental setups, including superconducting circuits, organic molecules, semiconductor polaritons, and optomechanical systems, that have now achieved ultrastrong coupling. We conclude by discussing the many potential applications that these achievements enable in physics and chemistry.Key pointsUltrastrong coupling (USC) can be achieved by coupling many dipoles to light, or by using degrees of freedom whose coupling is not bounded by the smallness of the fine structure constant.The highest light matter coupling strengths have been measured in experiments with Landau polaritons in semiconductor systems and in setups with superconducting quantum circuits.With USC, standard approximations break down, allowing processes that do not conserve the number of excitations in the system, leading to a ground state that contains virtual excitations.Potential applications of USC include fast and protected quantum information processing, nonlinear optics, modified chemical reactions and the enhancement of various quantum phenomena.Now that USC has been reached in several systems, it is time to experimentally explore the new phenomena predicted for this regime and to find their useful applications.", "author_names": [ "Anton Frisk Kockum", "Adam Miranowicz", "Simone De Liberato", "Salvatore Savasta", "Franco Nori" ], "corpus_id": 51963566, "doc_id": "51963566", "n_citations": 465, "n_key_citations": 14, "score": 1, "title": "Ultrastrong coupling between light and matter", "venue": "", "year": 2018 }, { "abstract": "The following changes have been made to the original article: in the lower right panel of Fig. 1, opoelectrics has been corrected to optoelectronics; in the Box 1 footnote, rotating wave approximation has been corrected to rotating wave approximation; in equation B1.3, an operator symbol has been added to the last term; and in the third paragraph of Box 2, |j |n> was changed to |j> |n> This has been corrected in the HTML and PDF versions of the article.", "author_names": [ "Anton Frisk Kockum", "Adam Miranowicz", "Simone De Liberato", "Salvatore Savasta", "Franco Nori" ], "corpus_id": 128011062, "doc_id": "128011062", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Publisher Correction: Ultrastrong coupling between light and matter", "venue": "Nature Reviews Physics", "year": 2019 }, { "abstract": "The strength of the coupling between an atom and a single electromagnetic field mode is defined as the ratio of the vacuum Rabi frequency to the Larmor frequency, and is determined by a small dimensionless physical constant, the fine structure constant \\alpha =Z_{vac} 2R_{K} a Z vac 2 R K On the other hand, the quantum circuit including Josephson junctions behaving as artificial atoms and it can be coupled to the electromagnetic field with arbitrary strength (Devoret et al. 2007) Therefore, the circuit quantum electrodynamics (circuit QED) is extremely suitable for studying much stronger light matter interaction.", "author_names": [ "Kouichi Semba" ], "corpus_id": 226316889, "doc_id": "226316889", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Emerging Ultrastrong Coupling Between Light and Matter Observed in Circuit Quantum Electrodynamics", "venue": "", "year": 2020 }, { "abstract": "Recent experiments have demonstrated that light and matter can mix together to an extreme degree, and previously uncharted regimes of light matter interactions are currently being explored in a variety of settings. The so called ultrastrong coupling (USC) regime is established when the light matter interaction energy is a comparable fraction of the bare frequencies of the uncoupled systems. Furthermore, when the interaction strengths become larger than the bare frequencies, the deep strong coupling (DSC) regime emerges. This article reviews advances in the field of the USC and DSC regimes, in particular, for light modes confined in cavities interacting with two level systems. An overview is first provided on the theoretical progress since the origins from the semiclassical Rabi model until recent developments of the quantum Rabi model. Next, several key experimental results from a variety of quantum platforms are described, including superconducting circuits, semiconductor quantum wells, and other hybrid quantum systems. Finally, anticipated applications are highlighted utilizing USC and DSC regimes, including novel quantum optical phenomena, quantum simulation, and quantum computation.", "author_names": [ "P Forn-D'iaz", "Lucas Lamata", "Enrique Rico", "Junichiro Kono", "Enrique Solano" ], "corpus_id": 119040982, "doc_id": "119040982", "n_citations": 265, "n_key_citations": 10, "score": 0, "title": "Ultrastrong coupling regimes of light matter interaction", "venue": "Reviews of Modern Physics", "year": 2019 }, { "abstract": "", "author_names": [ "R Sagastizabal", "N K Langford", "Marios Kounalakis", "Christian Dickel", "A Bruno", "F Luthi", "David J Thoen", "Akira Endo", "Leonardo DiCarlo" ], "corpus_id": 125588212, "doc_id": "125588212", "n_citations": 74, "n_key_citations": 0, "score": 0, "title": "Experimentally simulating the dynamics of quantum light and matter at ultrastrong coupling using circuit QED (2) light dynamics and light matter entanglement", "venue": "", "year": 2017 }, { "abstract": "Vincenzo Macri, Fabrizio Minganti, 2, Anton Frisk Kockum, Alessandro Ridolfo, 5 Salvatore Savasta, 6 and Franco Nori 7, 8 Theoretical Quantum Physics Laboratory, RIKEN, Wako shi, Saitama 351 0198, Japan Institute of Physics, Ecole Polytechnique Federale de Lausanne (EPFL) CH 1015 Lausanne, Switzerland Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden Dipartimento di Fisica e Astronomia, Universita di Catania, 95123 Catania, Italy INFN Sezione Catania, Catania, Italy Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Universita di Messina, I 98166 Messina, Italy RIKEN Center for Quantum Computing (RQC) Wakoshi, Saitama 351 0198, Japan Physics Department, The University of Michigan, Ann Arbor, Michigan 48109 1040, USA (Dated: July 20, 2021)", "author_names": [ "Vincenzo Macri", "Fabrizio Minganti", "Anton Frisk Kockum", "Alessandro Ridolfo", "Salvatore Savasta", "Franco Nori" ], "corpus_id": 236087976, "doc_id": "236087976", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Revealing higher order light and matter energy exchanges using quantum trajectories in ultrastrong coupling", "venue": "", "year": 2021 }, { "abstract": "In the ultrastrong light matter coupling regime, non perturbative effects are observed even for large detuning of the light and matter frequencies. In this regime, the rotating wave approximation breaks down and the contributions of counter rotating and diamagnetic terms lead to significant spectral modifications. Using split ring resonators coupled to the cyclotron transition in a two dimensional electron gas, we show that the diamagnetic terms lead to an asymmetry between the light and matter branches. Our system allows tuning both, the cavity and the matter frequency over more than two octaves. We find, that the assumption of constant coupling rate O as function of detuning is not generally valid for the large frequency range relevant to ultrastrong coupling phenomena.", "author_names": [ "Curdin Maissen", "Giacomo Scalari", "Mattias Beck", "Jerome Faist" ], "corpus_id": 4509846, "doc_id": "4509846", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Asymmetry in polariton dispersion as function of light and matter frequencies in the ultrastrong coupling regime", "venue": "", "year": 2017 }, { "abstract": "", "author_names": [ "Marios Kounalakis", "N K Langford", "R Sagastizabal", "Christian Dickel", "A Bruno", "F Luthi", "David J Thoen", "Akira Endo", "Leonardo DiCarlo" ], "corpus_id": 126290376, "doc_id": "126290376", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Experimentally simulating the dynamics of quantum light and matter at ultrastrong coupling using circuit QED (1) implementation and matter dynamics", "venue": "", "year": 2017 }, { "abstract": "In this paper we propose an efficient method for creating macroscopically distinct mechanical superposition states in an ultra strongly coupled light matter system. By modulating the opto mechanical coupling sinusoidally, the radiation pressure can be turned into a built in resonant driving force effectively. Thus the mechanical displacement can be significantly amplified.", "author_names": [ "Li Zheng", "Dong-ni Chen", "Zhenyun Peng", "Ying Shi", "Yujie Liu", "Ying-Dan Wang" ], "corpus_id": 214089750, "doc_id": "214089750", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Macroscopic Quantum Superposition in Opto Mechanical System with Ultrastrong Coupling Light Matter Interaction", "venue": "", "year": 2020 }, { "abstract": "In a recent work of ours [Phys. Rev. Lett. 112, 073601 (2014) we generalized the Power Zineau Woolley gauge to describe the electrodynamics of atoms in an arbitrary confined geometry. Here we complement the theory by proposing a tractable form of the polarization field to represent atomic material with well defined intra atomic potential. The direct electrostatic dipole dipole interaction between the atoms is canceled. This theory yields a suitable framework to determine limitations on the light matter coupling in quantum optical models with discernible atoms. We find that the superradiant criticality is at the border of covalent molecule formation and crystallization.", "author_names": [ "Andras Vukics", "Tobias Griesser", "Peter Domokos" ], "corpus_id": 118372295, "doc_id": "118372295", "n_citations": 25, "n_key_citations": 1, "score": 0, "title": "Fundamental limitation of ultrastrong coupling between light and atoms", "venue": "", "year": 2015 } ]