Observation and Manipulation of Semiconductor Surface Microstructure in Solution

1.激光点扫描显微镜（LSSM）的研制：研制了一种用于现场测量的新型LSSM系统。为了提高测量的效率，系统中使用了两台个人计算机。系统的控制和数据采集由8位机器执行，数据由32位机器传输和分析。该系统被应用于半导体/电解质界面的光电化学过程的研究。对系统进行了理论分析，确定了半导体中少数载流子的扩散长度和半导体电极表面速率常数对显微镜分辨率的影响.扫描隧道显微镜（STM）的发展：将市售的STM转换为原位电化学STM系统，其可以以nm分辨率监测和记录金属和半导体电极的表面形态变化。研究了Cu在Pt上的沉积、半导体的光阳极溶解和电位循环引起的表面结构变化。作为扫描隧道显微镜的一个应用，尖端电流伏安法（TCV）被用来研究电解质界面的电位分布。在p-GaP和n-GaAs电极上证明了这种方法的可行性。

1. Development of Laser Spot Scanning Microscope (LSSM).Novel LSSM system for in-situ measurements has been developed. In order to improve the efficiency of the measurements, two personal computers are used in the system. Control of the system and data collection are carried out by a 8-bit machine and data are transferred and analyzed by a 32-bit machine. This system was applied to study the photo electrochemical processes at semiconductor/electrolyte interfaces. Theoretical analysis of the system was also carried out and effect of diffusion length of minority carrier in the semiconductor and rate constant at semiconductor electrode surface on resolution of the microscope were determined.2. Development of Scanning Tunneling Microscope (STM).Commercially available STM was converted to an in-situ, electrochemical STM system which can monitor and record the surface morphology change of metal and semiconductor electrodes with nm resolution. Cu deposition on Pt, photoanodic dissolution of semiconductor and surface structure change caused bypotential cycles were investigated. As an application of STM, nosel technique called tip current voltammetry (TCV) was proposed to study potential distribution at semiconducter electrolyte interfaces. Usefulness of this method was demonstrated at p-GaP and n-GaAs electrodes.