多晶和非晶薄膜材料的能量过滤电子衍射分析法

Energy Filtered Analysis of Amorphous and Polycrystalline Films

本文介绍了一种能快速准确分析薄膜材料微观结构的新技术──透射电子显微镜样品后扫描能量过滤电子衍射分析法．该技术利用常规的透射电子显微镜把选区衍射花样投到一个顺序电子能量损失谱仪的入口光阑上，让微机输出脉冲电压到样品后偏转线圈使衍射花样顺序扫过光阑进入谱仪中．检测零损失电子强度随散射矢量的径向分布，从而导出能显示近邻原子间距和配位数等结构信息的约化密度函数．根据多晶金薄膜的试验结果显示．文中给出的该项技术测出的最近邻原子间距可精确到０．００２ｎｍ，配位数的测定可精确到０．５．

In this paper a rapid and effective means for giving accurate structural information from amorphous and polycrystalline films is developed. This technique uses a conventional transmission electron microscope to project a selected area diffraction patttern onto the entrance plane of a serial electron energy loss spectrometer. Scanning of the diffraction pattern can be done by deflection coils positioned close to the objective plane of the project lens.With the aid of computer, the elastic scattering intensity distribution is collected as a function of the scattering vector and derived to the reduced density function which displays the nearest neighboring distances and coordination numbers. The results of a thin An polycrystalline film showed that the experimental values of the nearest neighbor are accurat to 0. 002 nm, with coordination numbers whose accuracy depends upon the alloy system investigated.