Diffraction Studies of Epitaxy

这是一项研究的影响，结构的 分子束作用下砷化镓衬底表面 化合物半导体的外延生长和 金属. 这项研究利用反射高能电子 衍射和透射电子显微镜来表征 结构。 研究了晶体取向差对 原子的生长和扩散的稳定性将是 测定 研究结果将使 化合物外延生长模型的建立 半导体 根据以前的赠款（DMR-8319821）。 科恩教授 在该领域取得重大进展：（一）改进 对反射高能电子衍射的认识 这些材料中的工艺，例如，影响的测定 干涉对衍射角依赖性的影响 振荡，（ii.）镓表面扩散测量 砷化物，（iii.）确定控制 砷化镓的蒸发和生长 单个原子层，（iv.）测量厚度， 砷化铟镓薄膜可以在开始之前生长 与应变有关的缺陷。 这些和其他进步是 在超过七个科学出版物中描述。 科恩教授被公认为 科学家在现场。 设施和机构 环境是优秀的研究和性能 培训学生。 他在之前的国家科学基金会资助下的研究 被他的同行们列为 领域 该计划包括研究经验， 两名本科生的本科生补充金 在研究方面的实践经验。 希望这一 经验将成为吸引高天赋人才的刺激因素 学生进入研究和教学职业，以及 为实现该计划的总体目标做出贡献。

This is a study of the effects of the structure of the surface of gallium arsenide substrates upon the molecular beam epitaxial growth of compound semiconductors and thin films of metals. The study utilizes reflection high-energy electron diffraction and transmission electron microscopy to characterize the structures. The effects of misorientation of the crystals on the stability of growth and the diffusion of atoms will be determined. The results of the research will enable the formulation of a model for the epitaxial growth of compound semiconductors. Under the previous grant (DMR-8319821). Professor Cohen made significant advances in the field: (i.) improved understanding of reflection high-energy electron diffraction processes in these materials, e.g., determination of the effects of interference on angular dependence of diffraction oscillations, (ii.) measurement of surface diffusion on gallium arsenide, (iii.) determination of means to control the evaporation and growth of gallium arsenide on the level of individual atomic layers, (iv.) measurement of the thickness that indium gallium arsenide thin films can be grown before the onset of strain-related defects. These and other advances are described in more than seven scientific publications. Professor Cohen is acknowledged as one of the leading scientists in the field. The facilities and the institutional environment are excellent for the performance of the research and training of students. His research under the previous NSF grant has been classified by his peers as the pioneering work in the field. The program includes a Research Experience for Undergraduates Supplement for two undergraduate students to get hands-on experience in research. It is hoped that this experience will serve as a stimulus to attract highly-gifted students into research and teaching careers as well as to contribute to the overall goals of this program.