Electron Optical Studies of Crystal Disorders, Defects and Surfaces

这笔赠款是约翰·考利教授关于使用高分辨率电子显微镜研究陶瓷和电子材料缺陷和表面结构的更新。目前的研究集中在一系列新技术和现有技术的进一步发展上，以更详细地描述晶体表面的结构和化学成分以及薄膜和小颗粒中的原子无序。在反射电子显微镜中，我们将研究表面共振沟道效应，即将电子束限制在晶体表面原子的最顶线或平面上。这些效应在反射高能电子衍射的菊内线图案中观察到，它们为这个小组开发的称为电子能量损失光谱的技术提供了基础。这些新技术允许对表面单分子层进行微观化学和原子分析。这些技术正被应用于氧化物陶瓷(如氧化镁)和半导体(如硅和砷化镓)的表面研究。本研究将使用两台新的超高真空高分辨率电子显微镜。多年来，考利教授的研究一直处于高分辨率电子显微镜的前沿。它导致了当今世界范围内使用的几种技术。本研究将继续推进这些技术，以及它们在原子尺度上表征陶瓷和电子材料方面的应用。亚利桑那州立大学的这个小组继续培训研究生和博士后使用这些先进的分析技术。

This grant is a renewal for research by Professor John Cowley on the use of high resolution electron microscopy for the investigation of the structure of defects and surfaces of ceramic and electronic materials. The current research concentrates on a range of new techniques and the further advancement of established techniques for the more detailed atomic description of the structures and chemical compositions of crystal surfaces and atomic disorder in thin films and small particles. The effects of surface resonance channelling, which confine the electron beam to the topmost lines or planes of atoms on crystal surfaces will be investigated for the reflection electron microscope. These effects are observed in the Kikuchi line patterns in reflection high energy electron diffraction, and they provide for the basis for the technique developed by this group called electron energy loss spectroscopy. These new techniques allow micro-chemical and atomic analysis of surface monolayers. These techniques are being applied to studies of surfaces of oxide ceramics (e.g. magnesium oxide) and semiconductors (e.g. silicon and gallium arsenide). Two new ultra high vacuum high resolution electron microscopes are to be used for this study. The research of Professor Cowley has been at the leading edge of high resolution electron microscopy for years. It has led to several of the techniques in use worldwide today. The present research will continue to advance these techniques, and their use in characterization of ceramics and electronic materials on the atomic scale. This group at Arizona State University continues to train graduate students and post doctoral students in the use of these advanced analytical techniques.