一类非平衡半导体方程的整体弱解

考虑一类半导体方程的混合初边值问题，在迁移率既不为常数，又不满足速度饱和及初值u0i属于L^2（Ω）的条件下，证明了整体弱解的存在性。     

半导体压电型纳米环诞生

据美国Science,2004,303:1348报道,美国亚特兰大佐治亚理工学院王中林教授领导的研究小组在世界上首次得到具有压电效应的半导体纳米环结构.该研究成果是继王中林2001年首次发现半导体纳米带结构后又一重大原创性成果.     

基于寄生参数的功率MOSFET数学建模及损耗分析

为了精确地描述功率金属氧化物半导体场效应管(MOSFET)的开关特性,建立了一种基于MOSFET的寄生参数(Miller电容和寄生电感)的数学模型。该模型中采用拟合法分别构建Miller电容的数学表达式和转移特性的数学表达式,并详细推导了开关过程中电压和电流的数学表达式。针对关断后出现的电压、电流振荡建立的物理等效电路进行了分析。越精确的电压和电流数学表达式越能准确地反映功率MOSFET的开关损耗。仿真实验验证了本文数学分析模型和物理等效电路的正确性和有效性。     

Hydrogenation of nanostructured semiconductors for energy conversion and storage

Nanostructured semiconductors have been researched intensively for energy conversion and storage applications in recent decades. Despite of tremendous find- ings and achievements, the performance of the devices resulted from the nanomaterials in terms of energy conversion efficiency and storage capacity needs further improvement to become economically viable for subsequent commercializa- tion. Hydrogenation is a simple, efficient, and cost-effective way for tailoring the electronic and morphological properties of the nanostructured materials. This work reviews a series of hydrogenated nanostructured materials was produced by the hydrogenation of a wide range of nanomaterials. These materials with improved inherent conductivity and changed characteristic lattice structure possess much enhanced per- formance for energy conversion application, e.g., photo- electrocatalytic production of hydrogen, and energy storage applications, e.g., lithium-ion batteries and supercapacitors. The hydrogenation mechanisms as well as resultant properties responsible for the efficiency improvement are explored in details. This work provides guidance for researchers to use the hydrogenation technology to design functional materials.     

The influence of probe lift-up height on CNT electrical properties measurement under EFM DC mode

Nowadays, one of the bottlenecks which hinder the development and application of carbon nanotube （CNT） nano device is that no pure semiconducting CNT （s-CNT） or metallic CNT （m-CNT） can be obtained, and for solving this problem scientists proposed some methods on preparation or separation, but all the results still should be detected and feedback to the process for further improving the preparation and separation methods. Thus, it is very important to measure and distinguish the electrical properties of CNT. For that, scientists proposed a method to measure CNT electrical properties based on DC elec- trostatic force microscope （EFM） mode, which distin- guishes m-CNT from s-CNT according to different scan line shape to CNT with different electrical properties. But, we discovered that the probe lift-up height will seriously affect the shape of the scan line, which makes this method not reliable in distinguishing m-CNT from s-CNT. In this paper, the authors deeply researched the influence of probe lift-up height and also gave corresponding theoretical analysis and explanation, which will greatly improve the method of detecting CNT electrical properties by EFM.     

基于遗传算法的半导体生产线调度研究进展

半导体生产线调度是制造系统实际生产中的重要问题,也是理论研究的难点之一.遗传算法是计算智能的主要研究对象,因此基于遗传算法的半导体生产线调度研究,具有非常重要的研究价值和实践意义,已经引起了国内外研究者的广泛关注.文中评述近几年来在半导体生产线调度优化中遗传算法的应用,详细介绍了算法编码、操作、参数的选择、算法的改进及具体应用,并指出这一领域中值得进一步研究的一些问题和可能的发展方向.     

Pb2+掺杂对Cd1-xZnxS光催化产氢性能的影响规律

采用共沉淀法制备了Pb2 掺杂的Cd0.2Zn0.8S及Cd0.8Zn0.2S固溶体光催化剂.实验结果表明,Pb2 掺杂的宽带隙固溶体Cd0.2Zn0.8S在6s轨道与固溶体的价带杂化后提升了价带位置,降低了半导体的带隙,因而提高了产氢活性.当Pb2 掺杂窄带隙固溶体Cd0.8Zn0.2 S后,形成固溶体价带附近的杂质能级,并成为光生电子空穴复合中心,因而不能提高产氢性能.因此,Pb2 对半导体的可见光改性仅适用于较宽带隙的半导体.     

GaN基垂直腔面发射激光器的研制

作者在我国大陆首次实现了GaN基垂直腔面发射激光器(VCSEL)的激射.首先采用金属有机物化学气相沉积(MOCVD)技术在蓝宝石衬底上进行高质量氮化物增益区的外延生长,然后在表面沉积高反射介质膜分布布拉格反射镜(DBR).将样品键合到其它支撑片上后,采用激光剥离技术将蓝宝石村底去除.再在去除蓝宝石后露出的氮化物表面沉积第二组介质膜DBR制成VCSEL.在室温光泵条件下,观察到VCSEL的激射,激射波长449.5 nm.阈值6.5 mJ/cm2,激射峰的半高宽小于0.1 nm,这些指标达到了国际领先水平.本文为进一步研制实用化氮化物VCSEL奠定了重要的基础.     

Structure and 57Fe conversion electron Mössbauer spectroscopy study of Mn-Zn ferrite nanocrystal thin films by electroless plating in aqueous solution

Mn1-xZnxFe2O4thin films with various Zn contents and of different thickness were synthesized on glass substrates directly by electroless plating in aqueous solution at 90℃ without heat treatment. The Mn-Zn ferrite films have a single spinel phase structure and well-crystallized columnar grains growing per- pendicularly to the substrates. The results of conversion electron ^57Fe Mossbauer spectroscopy （CEMS） Indicate that the cation distribution of Mn1-xZnxFe204 ferrite nanocrystal thin films fabricated by electroless plating is different from the bulk materials＇ and a great quantity of Fe^3＋ ions are still present on A sites for x〉0.5. When the Zn content of the films increases, Fe^3＋ ions in the films transfer from A sites to B sites and the hyperfine magnetic field reduces, suggesting that Zn2. has strong chemical affinity towards the A sites. On the other side, with the increase of the thickness of the films, Fe3＋ ions, at B sites in the spinel structure, increase and the array of magnetic moments no longer lies in the thin film plane completely. At x = 0.5, Hc and Ms of Mn1-xZnxFe204thin films show a minimum of 3.7 kA/m and a maximum of 419.6 kA/m, respectively.     

V^2＋在ZnS中光谱的理论计算

用分子轨道理论推导了3d^3离子在立方晶体场中的哈密顿矩阵,并计算了V^2＋在ZnS中的吸收光谱.与其他近似方法相比较,该计算结果与实验符合得好,表明V^2＋在ZnS中,共价因素和Racah参量A的贡献是很大的.理论计算出的一条近红外谱线有待实验的进一步检验.