ELECTRON SPECTROSCOPIC MICROSCOPY IN MATERIALS SCIENCE

我们调查的性能和适用性的新能源过滤透射电子显微镜，这是最近安装在九州大学（KU），并与马克斯普朗克研究所和亚利桑那州立大学的显微镜进行比较。KU的新显微镜具有Shottcky型场发射枪和omega型成像滤波器。成像能谱仪使我们能够使用非弹性散射电子中包含的信息，并提高放大图像的对比度以及衍射图案。(1)电子分光成像：通过改变能量选择狭缝的位置和宽度，我们可以选择要用于成像的电子的能量。在多光束分辨率图像以及明场或暗场图像中，尽管物镜孔径的大小和位置在这些成像模式中不同，但是滤波零损失图像的对比度得到改善。金属和合金中的共格沉淀物、堆垛层错和位错的图像在过滤的零损失图像中是清晰的。在较厚的样品和较低的加速电压下，能量过滤效应明显。过滤后的核损失（内壳电离）图像包括材料中特定元素的组成信息（元素映射）。硅水中的薄氧化物层在过滤的K-损失氧图像中以二维尺度可视化。(2)电子光谱衍射：通过改变衍射模式中的能量狭缝来获得能量过滤的衍射图案。非弹性散射的电子是衍射图案中的背景的原因。零损耗滤波后的衍射图背景被很好地消除，对比度得到很大改善。在选区衍射图中可以观察到弱衍射斑或弥散极大值，在会聚电子衍射图中可以观察到高阶劳厄区的弱衍射线。

We investigated performance and applicability of the new energy filtering transmission electron microscope which was recently installed in Kyushu University (KU), and compared with those of microscopes in Max-Planck Institute and Arizona State University. The new microscope in KU has a field emission gun of Shottcky type and an imaging filter of omega-type. The imaging energy spectrometer enables us to use the information included in the inelastically scattered electrons and to improve the contrasts of magnified images as well as diffraction patterns.(1) Electron spectroscopic imaging : By changing a position and a width of energy selecting slit, we can select the energy of electrons to be used for imaging. The contrasts of filtered zero-loss images are improved in the multi-beam resolution images as well as bright-field or dark-field images, although the size and position of an objective apertureare are different in these imaging modes. Images of coherent precipitates, stacking faults and dislocations in metals and alloys are sharp in filtered zero-loss images. The effect of energy filtering is pronounced in thicker spsecimen and lower accelerating voltage. A filtered core-loss (inner-shell ionization) image includes information on composition of a particular element in material (element mapping). Thin oxide layer in Si water is visualized in a two-dimensional scale in the filtered K-loss oxygen image.(2) Electron spectroscopic diffraction : Energy filtered diffraction patterns are obtained by changing the energy slit in the diffraction mode. Inelastically scattered electrons are responsible for the background in diffraction patterns. The background is well eliminated and contrast is much improved in the zero-loss filtered diffraction patterns. We can observe weak diffraction spots or diffuse maxima in the selected-area diffraction patters, and weak diffraction lines of a higher order Laue zone in convergent electron diffraction patters.