Elemental mapping in scanning transmission electron microscopy
Elemental mapping in scanning transmission electron microscopy
复制标题
扫描透射电子显微镜中的元素图谱
DOI：
10.1088/1742-6596/241/1/012061
复制
发表时间：
2010
影响因子：
1.9
通讯作者：
S. Stemmer
中科院分区：
文献类型：
--
作者：
L. Allen;A. J. D’Alfonso;S. Findlay;J. Lebeau;N. Lugg;S. Stemmer
我们讨论了原子分辨率的化学映射在扫描透射电子显微镜（STEM）的基础上的核心损失电子能量损失谱（EELS）和能量色散X射线（EDX）成像。使用EELS的化学映射可以产生违反直觉的结果，然而，可以使用第一原理计算来理解。基于EDX的实验化学图证实了这样的图总是可能直接解释的论文。这可以解释在这些成像条件下电离的有效光学势的局部性质。这是其次是一个游览到元素映射的补充技术，使用能量过滤透射电子显微镜（EFTEM）在传统的透射电子显微镜。然后，我们将考虑广泛使用的Z-对比度或高角度环形暗场（HAADF）成像技术，这是基于声子激发，其中最近已被证明，强度变化可以放置在一个绝对尺度上通过归一化测量强度的入射光束。结果，显示出良好的理论和实验之间的一致性，在几个百分点内，显示从PbWO 4样品的Z-对比成像。
We discuss atomic resolution chemical mapping in scanning transmission electron microscopy (STEM) based on core-loss electron energy loss spectroscopy (EELS) and also on energy dispersive X-ray (EDX) imaging. Chemical mapping using EELS can yield counterintuitive results which, however, can be understood using first principles calculations. Experimental chemical maps based on EDX bear out the thesis that such maps are always likely to be directly interpretable. This can be explained in terms of the local nature of the effective optical potential for ionization under those imaging conditions. This is followed by an excursion into the complementary technique of elemental mapping using energy-filtered transmission electron microscopy (EFTEM) in a conventional transmission electron microscope. We will then consider the widely used technique of Z-contrast or high-angle annular dark field (HAADF) imaging, which is based on phonon excitation, where it has recently been shown that intensity variations can be placed on an absolute scale by normalizing the measured intensities to the incident beam. Results, showing excellent agreement between theory and experiment to within a few percent, are shown for Z-contrast imaging from a sample of PbWO4 .
影响因子：
8.6
作者：
Bosman, M.;Keast, V. J.;Allen, L. J.
通讯作者：
Allen, L. J.