Analysis of Materials in Random System by Quantitative High-Resolution Transmission Electron Microscopy and Electron Diffraction

随机体系中的材料表现出与其结构有关的特性，从而使我们能够制造出新的功能器件。材料在拓扑或元胞随机系统中的结构分析是理解其性质的关键。本项目的目的是用定量高分辨电子显微镜(HRTEM)和电子衍射(ED)方法分析各种材料在拓扑或蜂窝随机体系中的晶体结构。在这个项目中获得的结果已在下一节所示的文献中得到报告。主要研究内容和结果如下：1.用中子和同步辐射X射线衍射法对胞状随机体系中的BaSn2x-Gt；TixFe4O11-gt；BiFeO3CaMn7O12gt；和Ba_3Ca1_&lt；+x&gt；Nb_&lt；2-x&gt；O_&lt；9-8&gt；，的晶体结构和磁结构进行了分析，并结合定量HRTEM结果进行了讨论。铁磁性与结构变形…用截面高分辨电子显微镜研究了冷磨Fe_x；1-x&gt；Al_x(x=0.35-0.42)雾化粉末中诱导出的更多离子。利用HRTEM、ED和大角度环形暗场STEM方法，借助于阴极发光扫描电子显微镜、能量色散X射线能谱、电子能量损失谱等手段，揭示了半导体SrTiO_3基陶瓷中氧空位和添加原子的分布，O、N、P原子在动态随机存储器中的分布，原子在GaAs/AlGaAs多层异质结中的扩散和析出，以及光敏染料分子在AgBr表面的吸附等随机现象。用带能量滤光片的高分辨电子显微镜在成像板上测量了Se、Sb和C非晶薄膜的电火花强度，以阐明这些非晶薄膜的结构。对楔形晶体中出现的与ED强度相关的等厚条纹进行了定量强度测量。较少

Materials in random systems exhibit characteristic properties which are ascribed to their structure, and thereby allow us to produce new functional devices. The structure analysis of materials in topological or cellular random system is the key point to understand their properties. The object of this project is to analyze the crystallographic structure of various materials in topological or cellular random system using quantitative high-resolution electron microscopy (HRTEM) and electron diffraction (ED) method. The results obtained in this project have been reported in literatures shown in the next section. The main subjects and results are as follows :1. The crystal and magnetic structure of BaSn_<2-x>Ti_xFe_4O_<11>, BiFeO_3, CaMn7O_<12> and Ba_3Ca1_<+x>Nb_<2-x>O_<9-8>, which are in cellular random system, have been analyzed using neutron and synchrotron X-ray diffraction method, and discussed taking account of the results of quantitative HRTEM.2. Ferromagnetism and structural distor … More tions induced in atomized Fe_<1-x>Al_x (x=0.35-0.42) powder particles by cold milling have been investigated using cross-sectional HRTEM.3. Random phenomena such as the distribution of oxygen vacancies and additive atoms in semiconducting SrTiO_3-based ceramics, the distribution of O, N, and P atoms in DRAM, the atom diffusion and precipitation in GaAs/AlGaAs multilayer heterostructure and the adsorption of photosensitive dye molecules on the AgBr surface have been disclosed using HRTEM, ED and high angle annular dark field STEM method with the aid of cathodoluminescence scanning electron microscopy, energy dispersive X-ray spectroscopy, electron energy loss spectroscopy.4. ED intensity of Se, Sb, and C amorphous films has been measured on imaging plates in a high-resolution electron microscope with an energy filter, to elucidate the structure of these amorphous films. The quantitative intensity measurements of equal thickness fringes appearing in wedge-shaped crystals, which are correlated with ED intensity, have been performed. Less