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ELECTRON SPECTROSCOPIC MICROSCOPY IN MATERIALS SCIENCE

材料科学中的电子能谱显微镜

基本信息

批准号：
10044166
负责人：
TOMOKIYO Yoshitsugu
金额：
$ 2.94万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10044166/
关键词：
imaging filter electron energym loss spectroscopy omega filter electron spectroscopic imaging electron spectroscopic diffraction elemental mapping inelastic scattering 電子顕微鏡収束電子回折非弾性散乱

项目摘要

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.

我们对九州大学（KU）最近安装的新型能量过滤透射电子显微镜的性能和适用性进行了研究，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了比较。 KU 的新型显微镜配有肖特基型场发射枪和欧米伽型成像滤光片。成像能谱仪使我们能够利用非弹性散射电子中包含的信息，提高放大图像和衍射图案的对比度。 (1)电子能谱成像：通过改变能量选择狭缝的位置和宽度，我们可以选择用于成像的电子的能量。尽管物镜孔径的大小和位置在这些成像模式中不同，但在多光束分辨率图像以及明场或暗场图像中，滤波后的零损失图像的对比度得到了改善。金属和合金中的相干析出物、堆垛层错和位错的图像在滤波后的零损失图像中清晰可见。能量过滤的效果在较厚的样品和较低的加速电压中更为明显。过滤后的铁芯损耗（内壳电离）图像包括材料中特定元素的成分信息（元素映射）。硅水中的薄氧化层在过滤的 K 损失氧图像中以二维尺度可视化。(2) 电子能谱衍射：通过改变衍射模式中的能量狭缝获得能量过滤的衍射图案。非弹性散射电子是衍射图案中背景的原因。零损耗滤波衍射图案中的背景得到了很好的消除，对比度也得到了很大的提高。我们可以在选定区域的衍射图案中观察到弱衍射斑或弥散极大值，以及在会聚电子衍射图案中观察到高阶劳厄区的弱衍射线。