Enhanced photocatalytic activity of bismuth molybdate via hybridization with carbon

The bismuth molybdate Bi_3.64Mo_0.36O_6.55 (BMO) was successfully synthesized by a rapid and convenient microwave-assisted method. Carbon was introduced to hybridize with BMO material (BMO/C) through the simple combination of hydrothermal process in the presence of glucose and subsequent calcination treatment in N₂ gas at 280 °C. The products were characterized by the study of X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS). The results indicated that carbon did not affect the final crystalline structure of BMO, but it had great influences on the photocatalytic activity of BMO towards rhodamine-B (RhB) degradation. The improved photocatalytic performance could be ascribed to the enhanced photogenerated electron-hole separation and more RhB adsorption associated with carbon.     

Raman studies of selenium nanowires under high pressure

The selenium nanowires with diameter of 70 nm and length of 40 μm were synthesized by a facile solution method. High-pressure behavior of Se nanowires has been investigated by in situ Raman scattering up to 20.2 GPa at room temperature. A reversible phase transition from hexagonal to monoclinic occurs at 18.1 GPa. This transition pressure is higher than that of 14.0 GPa for bulk Se. The intrinsic geometry and/or the increasing energy band gap of Se nanowires are considered to contribute to the increase of transition pressure.     

Hydrogen in semiconductors

Hydrogen in crystalline semiconductors has become a recent curiosity because of its high diffusivity and strong chemical activity in such materials. In contrast to the proton motion in ionic materials which gives rise to an enhanced conductivity, hydrogen in electronic materials interact with structural disorders and chemical impurities to control the electronic flow. Deep gap states in crystalline semiconductors due to various disorders such as surface/interface, grain boundaries, dislocations, irradiation and implantation damage etc. have been removed due to hydrogen bondings. Hydrogen incorporation is done by plasma and direct ion beam hydrogenation methods, implantation technique and by a novel technique of damage free introduction. The most studied materials are silicon and gallium arsenide.I - V,C - V, DLTS and IR studies have been carried out on hydrogenated semiconductors to characterize the electronic flow, gap states and the nature of chemical bonds. Improvement in ideality factors of diodes, reduction in free carrier concentration, removal or reduction of deep states and appearance of new bondings such as Si-H, P-H, B-H etc. have been observed from various techniques. The present paper reviews the various features of hydrogenation studies in crystalline silicon and gallium arsenide and highlights our results of hydrogenation studies on Pd/semiconductor devices.     

Design considerations for thin film coated semiconductor thermal neutron detectors—I: basics regarding alpha particle emitting neutron reactive films

Semiconductor-based thermal neutron detectors provide a compact technology for neutron detection and imaging. Such devices can be produced by externally coating semiconductor-charged-particle detectors with neutron reactive films that convert free neutrons into charged-particle reaction products. Commonly used films for such devices utilize the ¹⁰B(n,)⁷Li reaction or the ⁶Li(n,)³H reaction, which are attractive due to the relatively high energies imparted to the reaction products. Unfortunately, thin film or “foil” type thermal neutron detectors suffer from self-absorption effects that ultimately limit neutron detection efficiency. Design considerations that maximize the efficiency and performance of such devices are discussed. Theoretical and experimental results from front coated, back coated, and “sandwich” designs are presented.     

A due-date based production control policy using WIP balance for implementation in semiconductor fabrications

Production control policies are critical in the re-entrant processes of semiconductor fabrication. Manufacturing control policies such as input dispatching rules, CONWIP, and optimization-based rules have been implemented according to the managerial objectives of the wafer fabrication line. When few semiconductor wafer fabrication facilities were available, and the semiconductor industry was a seller's market, fabrications were operated to achieve both a high rate of production and high utilization of equipment. With the availability of more fabrications and the gradual shift to a buyer's market, customer satisfaction became a major measure of performance in semiconductor manufacturing. In this paper, due-date based production control policies for semiconductor fabrications are suggested, and their performances evaluated. Target balance (TB) optimization models using production target, due-dates, and WIP (work-in-process) are presented. The evaluation result shows that the TB models perform better than the ones cited in the literature.     

An introduction to Chinese manufacturing research institutions

The manufacturing environment has dramatically changed in the last few years. Worldwide competition among manufacturers and the development of new manufacturing technologies have contributed to today's competitive situation in many manufacturing areas. Advanced computer technology is the driver that has made global manufacturing competition possible. In this paper, the current research of advanced manufacturing technology at major institutions in China is introduced.     

半导体激光器谱线展宽因子测量

以１．３μｍＤｈ－ＩｎＧａＡｓＰ半导体激光器为研究对象，利用自发辐射谱测量谱线展宽因子，测出了α因子随工作电流变化的关系曲线。     

A novel nonvolatile memory based on self-organized quantum dots

A novel type of memory based on self-organized quantum dots (QDs) is presented, which merges the advantages of the most important semiconductor memories, the dynamic random access memory (DRAM) and the Flash. A nonvolatile memory with fast access times and good endurance (>10¹⁵ write/erase cycles) as an ultimate solution seems possible. A storage time of 1.6 s at 300 K in InAs/GaAs QDs with an additional Al_0.9Ga_0.1As barrier is demonstrated and a retention time of 10⁶ years is predicted for GaSb QDs in an AlAs matrix. A minimum write time of 6 ns is obtained for InAs/GaAs QDs. This value is already in the order of the access time of a DRAM cell and at the moment limited by the RC low pass of the device. An erase time of milliseconds is shown in first measurements on GaSb/GaAs QDs at . Faster write/erase times below even at room temperature are expected for improved device structures.     

低温退火工艺对柔性基上ITO膜透光率的影响

国内外学者对铟锡氧化物膜的各种工艺参数进行了过广泛的研究，然而对低温退火提高ＩＴＯ膜的透光性还未见报道。文章在研究了低温退火工艺对柔性基上真空蒸镀ＴＩＯ膜的透光率的影响后，进一步分析了影响透光率的工艺参数。     

铟镓氮超高亮度蓝色发光二极管

从材料、器件、结构、特性及其应用等方面介绍了ＩｎＧａＮ超高亮度蓝色发光二极管，这种器件峰值波垂为４５０ｎｍ，外量子效率是２．７％，在正向电流２０ｍＡ时，亮度达１．２ｃｄ，正向压降为３．６Ｖ，比市售的其它蓝色发光二极管的亮度提高１００倍，其在上全色显示方面具有广阔的应用前景。