权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

The analysis of small point defect clusters by diffraction contrast image using high resolution electron microscopy

使用高分辨率电子显微镜通过衍射对比图像分析小点缺陷簇

基本信息

批准号：
03805057
负责人：
YOSHIIE Toshimasa
金额：
$ 0.96万
依托单位：
KYOTO UNIVERSITY (1992)Hokkaido University (1991)
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

For the study of radiation damage, statistical evaluation of radiation induced defect structures are essential. High resolution transmission electron microscopy has been one of the most powerful technique to investigate the type, the density and the size of point defect clusters. The diffraction contrast image, especially a dark-field image is commonly used for these studies. The relationship between observed image size and real defect size is, however not clear in the case of small clusters, especially in the order of 1nm size. The aim of this study was to develop the observation technique and the method of analysis for the diffraction contrast image of small defect clusters.Point defect clusters were introduced in metals and semiconductors by various method such as high energy particle irradiation and quenching from high temperatures. Experimental dark-field diffraction contrast image of stacking fault tetrahedra, dislocation loops and voids was examined under various conditions. Image of dislocation loops below 1nm was observed. They are distinguished from stacking fault tetrahedra using a 220 reflection if the size is above 2nm. For the image of stacking fault tetrahedra, 0.6nm for gold and 0.5nm for nickel were observed. Image of stacking fault and stair-rod dislocations were simulated based on the dynamical theory. Image of very small stacking fault tetrahedra was calculated by multi-slice method. Stacking fault instead of stair-rod dislocations have large contribution to the total stacking fault image. It is clarified that image size is smaller than the stacking fault size. The size difference depends on many parameters, but is always smaller than the fringe spacing of stacking fault tetrahedra. The contrast of stacking fault tetrahedra smaller than the fringe spacing sometimes goes out. Visible ratio is smaller for smaller deviation from the Bragg condition.

在辐射损伤研究中，辐射缺陷结构的统计评估是必不可少的。高分辨率透射电子显微镜是研究点缺陷簇的类型、密度和大小的最有力的技术之一。衍射对比图像，特别是暗场图像通常用于这些研究。然而，在小簇的情况下，特别是在1nm量级的情况下，观察到的图像尺寸与实际缺陷尺寸之间的关系并不清楚。本研究的目的是发展小缺陷团簇衍射对比图像的观察技术和分析方法。通过高能粒子辐照和高温淬火等方法，在金属和半导体中引入了点缺陷簇。研究了不同条件下层错四面体、位错环和空洞的实验暗场衍射对比图像。在1nm以下观察到位错环的图像。如果尺寸大于2nm，则使用220反射将其与层错四面体区分开来。对于层错四面体的图像，金的层错宽度为0.6nm，镍的层错宽度为0.5nm。基于动力学理论，模拟了层错和阶梯位错的图像。采用多层切片法计算了极小层错四面体的图像。层错对总层错图像的贡献较大，而不是阶梯位错。结果表明，图像尺寸小于层错尺寸。尺寸差异取决于许多参数，但始终小于层错四面体的条纹间距。小于条纹间距的层错四面体的对比度有时会消失。与布拉格条件的偏差越小，可见比就越小。