Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany.
Ultramicroscopy. 2013 Feb;125:66-71. doi: 10.1016/j.ultramic.2012.11.001. Epub 2012 Nov 17.
In electron scattering from crystals, diffraction spots are replaced by Kikuchi patterns at high momentum transfer. Kikuchi pattern formation is based on the concept of effective incoherent electron sources (or detectors) inside a crystal. The resulting incoherence is a consequence of energy transfer connected with the momentum transfer in large-angle scattering events. We identify atomic recoil as a key incoherent process giving rise to electron Kikuchi patterns in the scope of the "channeling-in and channeling-out" model of electron backscatter diffraction (EBSD) and electron channeling patterns (ECP) in the scanning electron microscope (SEM). Using model calculations, we explore the characteristic role of the localization of the incoherent scattering event at specific places within the unit cell. In this way, we explain why sometimes inelastic losses do cause Kikuchi-type contrast, and sometimes inelastic losses result in the disappearance of this contrast in the SEM.
在晶体中的电子散射中，在高动量传递时，衍射点被菊池花样所取代。菊池花样的形成基于晶体内部有效非相干电子源（或探测器）的概念。由此产生的非相干性是与大角度散射事件中的动量传递相关的能量转移的结果。我们将原子反冲确定为导致电子菊池花样的关键非相干过程，该过程在电子背散射衍射（EBSD）的“通道进入和通道退出”模型以及扫描电子显微镜（SEM）中的电子通道花样（ECP）的范围内。使用模型计算，我们探索了非相干散射事件在晶胞内特定位置的定位的特征作用。通过这种方式，我们解释了为什么有时非弹性损耗确实会导致菊池型对比度，而有时非弹性损耗会导致 SEM 中这种对比度的消失。
