Electron Microscopy in Surface Science

这项资助是为了更新约翰·C. H. Spence，亚利桑那州立大学，电子显微镜， 陶瓷和电子材料表面的研究。 期间 以前的赠款（DMR-8512784）超过12个实质性 在经过评审的科学期刊上发表了文章。 重大成就的亮点包括设计， 扫描隧道显微镜的结构和测试 它在透射电子显微镜内工作 （允许同时操作两种技术， 相同的标本）;技术称为会聚束电子 进行定量的微衍射以允许测定 砷化镓的电子基态电荷密度 (this允许确定化学键的性质， 这种技术上重要的材料）;理论上的进展 电子沟道效应对俄歇电子产生的影响 反射高能电子衍射技术提供了 分析手段，以确定吸附原子的原子位置上清洁 表面;一种新的方法，形成原子晶格图像， 半导体已经被开发，其允许半导体的晶格成像。 位错缺陷垂直于电子束， 分辨率为0.3纳米（灵敏度为 以前可能的）。 目前的研究将继续寻求 新技术的使用电子束研究 原子尺度上的陶瓷和电子材料结构 重点是理解扫描隧道效应 显微镜下，原子的位置通过沟道增强 研究半导体表面吸附原子的微观分析; 电子能谱从表面状态;和定量 电子晶体学用于化学键合的研究 晶体 斯宾塞教授被同行们称为 在美国使用电子显微镜的创新科学家。 一贯训练有素的高素质的学生在研究 电子显微镜是材料科学的重要领域。

This grant is for renewal of research by Professor John C. H. Spence, Arizona State University, on electron microscopy for study of surfaces of ceramics and electronic materials. During the previous grant (DMR-8512784) more than twelve substantive publications in refereed scientific journals were produced. Highlights of the significant accomplishments include design, construction and testing of a scanning tunnelling microscope which operates inside a transmission electron microscope (allowing simultaneous operation of the two techniques on the same specimen); the technique known as convergent beam electron microdiffraction was made quantitative to allow determination of the electron ground state charge density of gallium arsenide (this allows determination of the nature of the chemical bonds in this technologically important material); advances in theory of electron channeling effect on Auger electron production in the reflection high energy electron diffraction technique provided analytical means to determine the atomic site of adatoms on clean surfaces; a novel method for forming atomic lattice images in semiconductors has been developed which allows lattice imaging of dislocation defects normal to the electron beam with a resolution of 0.3 nanometer (ten times more sensitive than previously possible). The current research will continue to seek novel techniques for the use of electron beams to study the structure of ceramics and electronic materials on a atomic scale with emphasis on the understanding the scanning tunneling microscope, the atom location by channeling-enhanced microanalysis for study of adatoms on semiconductor surfaces; electron energy spectra from surface states; and quantitative electron crystallography for the study of chemical bonding in crystals. Professor Spence has been referred to by his peers as the most innovative scientist using electron microscopy in the U.S. He has consistently trained students of high quality for research in the important field of electron microscopy for materials science.