STUDIES OF THE PROMISING MATERIAL COSI2 ON GAAS SUBSTRATES

The thermal stability of CoSi2 thin films on GaAs substrates has been studied using a variety of techniques. The CoSi2 thin films were formed by depositing Co(500 angstrom) and Si(1800 angstrom) layers on GaAs substrates by electron-beam evaporation followed by annealing processes, where the Si inter-layer was used as a diffusion/reaction barrier at the interface. The resistivity of CoSi2 thin films formed is about 30 muOMEGA cm. The Schottky barrier height of CoSi2/n-GaAs is 0.76 eV and the ideality factor is 1.14 after annealing at 750-degrees-C for 30 min. The CoSi2/GaAs interface is determined to be thermally stable and the thin film morphologically uniform on GaAs after 900-degrees-C/30 s anneal. The CoSi2 thin films fulfill the requirements in GaAs self-aligned gate technology.

Pressure dependence of the electronic subband structure of strained In0.2Ga0.8As/GaAs MQWs

We have measured low-temperature photoluminescence (PL) and optical absorption spectra of an In0.2Ga0.8As/GaAs multiple quantum well (MQW) structure at pressures up to 8 GPa. Below 4.9 GPa, PL shows only the emission of the n = 1 heavy-hole (HH) exciton. Three new X-related PL bands appear at higher pressures. They are assigned to spatially indirect (type-II) and direct (type-I) transitions from X(Z) states in GaAs and X(XY) valleys of InGaAs, respectively, to the HH subband of the wells. From the PL data we obtain a valence band offset of 80 meV for the strained In0.2Ga0.8As/GaAs MQW system. Absorption spectra show three features corresponding to direct exciton transitions in the quantum wells. In the pressure range of 4.5 to 5.5 GPa an additional pronounced feature is apparent in absorption, which is attributed to the pseudo-direct transition between a HH subband and the folded X(Z) states of the wells. This gives the first clear evidence for an enhanced strength of indirect optical transitions due to the breakdown of translational invariance at the heterointerfaces in MQWs.

量子阱、超晶格结构的线性电光效应研究进展

本文综合比较了各种用以解释量子阱、超晶格结构线性电光效应(LEO)的理论和模型,如:EFT理论,GBC理论,HBF模型等;并按三种量子阱结构:阱区和势垒层具有一种相同原子的I型量子阱(CA-QWs)、阱区和势垒层不具有相同原子的I型量子阱(NCA-QWs)以及II型量子阱,给出了具体的量子阱超晶格结构线性电光效应的研究现状;最后总结了目前硅基量子阱、超晶格LEO的一些研究结果,并分析指出了对其作进一步研究的发展方向.

用微结构改进InGaAlP量子阱发光二极管的出光强度

针对半导体发光二极管（LED）出光效率低下的问题，提出了一个LED顶部引入周期性微结构的新设想。根据这一设想，采用简单的微加工技术研制成功带有环形槽微结构的圆台形InGaAlP量子阱LED。结明表明，这种新型LED在竖直方向的出射光强比不带微结构的LED有明显增强。这一成功为改进发光二极管的出光效率提供了新的途径。

GaAs研磨片化学腐蚀均匀性的分析

采用不同的化学腐蚀方法，探讨了不同体系成份、温度、腐蚀过程的吸放热对晶片均匀性的影响，提出氨水系列，进行晶片化学腐蚀，晶片厚度均匀性11.47%，为下步工艺提供平整度较好的晶片。

分布布拉格反射器（DBR）对半导体微腔一些特性的影响

从光学传输矩阵方法出发，研究了分布布拉格反射器(DBR)生长顺序的不同对半导体平面微腔中电场振幅极大值位置及整个微腔选频特性的影响；同时指出了DBR对于λ_0/2和λ_0腔不同情况的最佳生长模式。

自组织InAs/GaAs岛状结构生长停顿研究

报道了自组织生长InAs/GaAs岛状结构生长停顿的研究结果。在完成InAs岛生长以后，引入不同时间的停顿，然后再淀积GaAs盖层，将导一致InAs岛光致发光峰蓝移，发光谱线变宽，同时发光强度减弱。透射电子显微镜分析表明在这种结构中出了失配位错，在其附近应变得到部分弛豫，成为InAs材料的俘获陷阱。随着停顿时间加长，InAs岛密度降低，尺寸变小，光致发光谱发生相应变化。

基于实时数据库的卫星测试平台的设计与实现

卫星测试数据的有效存储与展现对卫星测试有着重要的意义,同时随着卫星技术的发展,一颗卫星的多阶段测试,多颗卫星同时测试是不可避免的.而及时有效的处理测试产生大量的实时数据将是极大的挑战.设计并实现了基于实时数据库的分布式卫星测试平台,可以有效地管理多颗卫星的测试,同时结合ACE框架的通讯结构可以有效的对测试问内外的测试人员提供实时的数据监视与精确的历史查询统计.