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Defect formation of CuI-doped by group-IIB elements
摘要： First-principles calculations have been performed to investigate the doping defects in CuI with group-IIB elements such as Zn, Cd and Hg. The calculated transition energies for substitutional Zn, Cd and Hg are 1.32, 1.28 and 0.60 eV, respectively. These group-IIB elements at the substitutional sites complex with a copper vacancy (VCu) have the lower formation energies as compared to dopants located at the substitutional sites or interstitial sites, respectively. Among all the complex defects considered, [HgCu + VCu] has the lowest formation energy and it induces the acceptor level ε(0/?) = 0.18 eV above the valence-band maximum (VBM), which is close to the acceptor level ε(0/?) = 0.1 eV of VCu, suggesting that Hg may be a good dopant for CuI to improve its p-type conductivity.
关键词： group-IIB elements,defects formation,first-principles calculation,Semiconductor
更新于2025-09-23 15:23:52
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[IEEE 2018 International Semiconductor Conference (CAS) - Sinaia (2018.10.10-2018.10.12)] 2018 International Semiconductor Conference (CAS) - Interface Trap Effects in the Design of a 4H-SiC MOSFET for Low Voltage Applications
摘要： The current-voltage characteristics of a 4H-SiC MOSFET dimensioned for a breakdown voltage of 650 V are investigated by means of a numerical simulation study that takes into account the defect state distribution at the oxide-semiconductor interface in the channel region. The modelling analysis reveals that, for these low-voltage devices, the channel resistance component plays a key role in determining the MOSFET specific ON-state resistance (RON) under different voltage biases and temperatures. The RON value is in the order of a few mΩ×cm2.
关键词： numerical simulations,power devices,ON-state resistance,4H-SiC,defects states
更新于2025-09-23 15:23:52
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Electrical profiling of arsenic-implanted HgCdTe films performed with discrete mobility spectrum analysis
摘要： Results of electrical profiling of an n-on-p junction formed by 190-keV arsenic ion implantation in indium/vacancy–doped Hg0.78Cd0.22Te film are presented. Mobility spectrum analysis in combination with wet chemical etching has been employed for the profiling. After the implantation, a typical n+-n–p structure was observed and three electron species were detected: (a) low-mobility electrons in the 400-500 nm-thick top radiation-damaged n+-layer, (b) mid-mobility electrons also originating from radiation damage and spreading down to 700-900 nm, and (c) high-mobility electrons located in the n-region extending beyond 700-900 nm and down to the p-n junction. A comparison of the extracted electron parameters with the arsenic profile obtained with secondary-ion mass spectroscopy as well as with the defect pattern obtained with transmission electron microscopy allowed for identification of the origin of all the three electron species.
关键词： HgCdTe,arsenic implantation,defects,electrical profiling
更新于2025-09-23 15:23:52
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Paramagnetic surface defects in LiMgPO<sub>4</sub>
摘要： The EPR spectra obtained at 300 K and 115 K are indicative of the existence of charged defects in LiMgPO4. The main imperfections are identified as a radical CO-3 (g=2) and a singly charged oxygen vacancy (g1=2.45, g2=2.20, g3=2.00). The presence of carbon-containing groups is proved by Raman spectroscopy. The assumption is made that the defects are located mainly on the surface of the grains. Thermoluminescent characteristics of LiMgPO4 annealed in atmospheres with different pO2 demonstrate that the surface defects impair the efficiency of LiMgPO4 as a dosimetric material.
关键词： Thermoluminescence.,Defects,EPR,Raman spectroscopy,LiMgPO4
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference on Cyberworlds (CW) - Singapore, Singapore (2018.10.3-2018.10.5)] 2018 International Conference on Cyberworlds (CW) - Towards Automatic Optical Inspection of Soldering Defects
摘要： This paper proposes a method for automatic image-based classification of solder joint defects in the context of Automatic Optical Inspection (AOI) of Printed Circuit Boards (PCBs). Machine learning-based approaches are frequently used for image-based inspection. However, a main challenge is to manually create sufficiently large labeled training databases to allow for high accuracy of defect detection. Creating such large training databases is time-consuming, expensive, and often unfeasible in industrial production settings. In order to address this problem, an active learning framework is proposed which starts with only a small labeled subset of training data. The labeled dataset is then enlarged step-by-step by combining K-means clustering with active user input to provide representative samples for the training of an SVM classifier. Evaluations on two databases with insufficient and shifting solder joints samples have shown that the proposed method achieved high accuracy while requiring only minimal user input. The results also demonstrated that the proposed method outperforms random and representative sampling by ~ 3.2% and ~ 2.7%, respectively, and it outperforms the uncertainty sampling method by ~ 0.5%.
关键词： Classification of solder joint defects,active learning,Automatic Optical Inspection (AOI),SVM classifier,K-means
更新于2025-09-23 15:23:52
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Diversity of TiO <sub/>2</sub> : Controlling the Molecular and Electronic Structure of Atomic-Layer-Deposited Black TiO <sub/>2</sub>
摘要： Visually black, electrically leaky, amorphous titania (am-TiO2) thin films were grown by atomic layer deposition (ALD) for photocatalytic applications. Broad spectral absorbance in the visible range and exceptional conductivity are attributed to trapped Ti3+ in the film. Oxidation of Ti3+ upon heat treatment leads to a drop in conductivity, a color change from black to white and crystallization of am-TiO2. ALD grown black TiO2, without any heat treatment, is subject to dissolution in alkaline photoelectrochemical conditions. The best photocatalytic activity for solar water splitting is obtained for completely crystalline white TiO2.
关键词： atomic layer deposition,photocatalysis,titanium dioxide,protecting overlayers,crystallization,oxide defects,water splitting
更新于2025-09-23 15:23:52
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Comparative Analysis of Defects in Mg-Implanted and Mg-Doped GaN Layers on Freestanding GaN Substrates
摘要： Inefficient Mg-induced p-type doping has been remained a major obstacle in the development of GaN-based electronic devices for solid-state lighting and power applications. This study reports comparative structural analysis of defects in GaN layers on freestanding GaN substrates where Mg incorporation is carried out via two approaches: ion implantation and epitaxial doping. Scanning transmission electron microscopy revealed the existence of pyramidal and line defects only in Mg-implanted sample whereas Mg-doped sample did not show presence of these defects which suggests that nature of defects depends upon incorporation method. From secondary ion mass spectrometry, a direct correspondence is observed between Mg concentrations and location and type of these defects. Our investigations suggest that these pyramidal and line defects are Mg-rich species and their formation may lead to reduced free hole densities which is still a major concern for p-GaN-based material and devices. As freestanding GaN substrates offer a platform for realization of p-n junction-based vertical devices, comparative structural investigation of defects originated due to different Mg incorporation processes in GaN layers on such substrates is likely to give more insight towards understanding Mg self-compensation mechanisms and then optimizing Mg doping and/or implantation process for the advancement of GaN-based device technology.
关键词： Line defects,Pyramidal defects,SIMS,GaN,STEM
更新于2025-09-23 15:22:29
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Effect of short-circuit stress on the degradation of the SiO2 dielectric in SiC power MOSFETs
摘要： This paper presents the impact of a short-circuit event on the gate reliability in planar SiC MOSFETs, which becomes more critical with increased junction temperature and higher bias voltages. The electrical waveforms indicate that a gate degradation mechanism takes place, showing a large gate leakage current that increases as the gate degrades more and more. A failure analysis has been performed on the degraded SiC MOSFET and then compared to the structure of a new device to identify possible defects/abnormalities. A Focused-Ion Beam cut is performed showing a number of differences in comparison to the new device: (i) cracks between the poly-silicon gate and aluminium source, (ii) metal particles near the source contact, and (iii) alterations in the top surface of the aluminium source. The defects have been correlated with the increase in gate-leakage current and drain-leakage current.
关键词： Focused-Ion Beam,Short circuit,Gate-oxide breakdown,Gate oxide,Degradation,Defects,Reliability,SiC MOSFET,Failure analysis,SEM
更新于2025-09-23 15:22:29
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Structure and Morphology of Cds Nanoparticles
摘要： The structure and morphology of CdS nanoparticles obtained by the hydrothermal synthesis are studied at temperatures of 80 °С, 100 °С, 120 °С, and 140 °С. The analysis is performed by calculating X-ray diffraction patterns by the Debye formula followed by the optimization of model parameters of nanocrystals. It is shown that with increasing temperature the CdS structure gradually transforms from a very defective sphalerite-like structure to very defective wurtzite-like one. At all temperatures the particles are ellipsoids stretched along the perpendicular to packing defects. An increase in the temperature causes a gradual enlargement of nanoparticles.
关键词： packing defects,simulation,particle shape,Debye formula,DISCUS
更新于2025-09-23 15:22:29
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Potential of Near-infrared Spectroscopy to Detect Defects on the Surface of Solid Wood Boards
摘要： Defects on the surface of solid wood boards directly affect their mechanical properties and product grades. This study investigated the use of near-infrared spectroscopy (NIRS) to detect and classify defects on the surface of solid wood boards. Pinus koraiensis was selected as the raw material. The experiments focused on the ability to use the model to sort defects on the surface of wood into four types, namely live knots, dead knots, cracks, and defect-free. The test data consisted of 360 NIR absorption spectra of the defect samples using a portable NIR spectrometer, with the wavelength range of 900 to 1900 nm. Three pre-processing methods were used to compare the effects of noise elimination in the original absorption spectra. The NIR discrimination models were developed based on partial least squares and discriminant analysis (PLS-DA), least squares support vector machine (LS-SVM), and back-propagation neural network (BPNN) from 900 to approximately 1900 nm. The results demonstrated that the BPNN model exhibited the highest classification accuracy of 97.92% for the model calibration and 97.50% for the prediction set. These results suggest that there is potential for the NIR method to detect defects and differentiate between types of defects on the surface of solid wood boards.
关键词： Surface defects,BPNN,PLS - DA,LS-SVM,Near-infrared spectroscopy,Solid wood boards
更新于2025-09-23 15:22:29