Atomistics of Kinks and Surfactants

9526100斯宾塞这个项目致力于研究导致半导体中位错运动的基本原子过程，以及表面活性剂在控制逐层外延晶体生长中的作用机制。重点研究的两个方面是：(1)在600℃用“禁止”反射的电子显微镜在硅中直接观察位错上的扭结运动，扭结的钉扎机制和扭结在不同部分位错上的相互关系，以及在原子水平上最终控制晶体延展性的因素是基本感兴趣的。(2)最近开发的扫描原子探针(SAP)将用于研究Ge在Si上生长过程中的表面活性剂作用，并验证低温外延生长早期的表面活性剂作用理论。SAP允许将来自STM图像中已识别位置的原子团喷射到飞行时间质谱仪中进行化学鉴定。理论分析，例如扭结迁移率的从头计算，是该项目不可分割的一部分。扫描原子探针(SAP)最近被开发出来，将用于电子和光子材料外延晶体生长过程中表面活性剂中介的基础研究。SAP和高分辨率电子显微镜都将被用来研究原子缺陷的运动，以及最终控制宏观材料性质的额外的原子水平现象。该计划的一个重要特点是在一个具有根本意义和技术意义的领域培养研究生和本科生。*。

9526100 Spence This project addressees research into fundamental atomic processes responsible for dislocation motion in semiconductors, and into the mechanism of surfactant action in controlling layer-by-layer epitaxial crystal growth. Two research aspects being emphasized are: (1)direct observation of kinks in motion on dislocations by atomic resolution electron microscopy using "forbidden" reflection TEM lattice imaging in silicon at 600C; pinning mechanisms of kinks and the correlations of kinks on different partial dislocation, and factors which ultimately control the ductility of crystals at the atomic level are of basic interest. (2) a recently developed Scanning Atom Probe (SAP) which allows groups of atoms from identified sites in an STM image to be ejected into a time-of-flight mass analyzer for chemical identification, will be used to study surfactant action during the growth of Ge on Si, and to test theories of surfactant action in the early stages of low-temperature epitaxial growth. Theoretical analyses, e.g., ab-initio computations of kink mobility, are an integral part of the project. %%% A Scanning Atom Probe (SAP) has recently been developed and will be used for basic research studies of surfactant mediation during epitaxial crystal growth of electronic and photonic materials. Both SAP and high resolution electron microscopy will be used to study the motion of atomic defects, and additional atomic level phenomena that ultimately control macroscopic material properties. An important feature of the program is the training of graduate and undergraduate students in a fundamentally and technologically significant area. *** .