Advanced electron backscatter diffraction applied to the characterisation of nanostructured nitride materials

电子背散射衍射（EBSD）是一种先进的扫描电子显微镜（SEM）技术，它能以几十纳米的空间分辨率快速、无损地提供材料结构特性的信息。特别是，对获得的EBSD模式的解释允许对样品中的晶体取向、晶体结构和应变分布进行映射。这些信息来源于地图上每个点的EBSD模式。EBSD模式由重叠的菊池带组成，菊池带是所研究晶体平面的投影。目前，商业软件主要利用这些波段的位置来确定晶体学信息。如果利用菊池带强度的细微变化，可以显著扩展EBSD技术的应用。这可以通过比较实验的EBSD模式和多束动态模拟模式来实现。到目前为止，在与布鲁克纳米的同事合作中，我们已经证明了在GaP中绘制反相域是可能的，并确定了GaN纳米棒的极性。该项目将在这项工作的基础上进行扩展，使纳米棒阵列的取向、晶体结构和极性得以绘制。它还将开发和探索新的直接电子探测器和下一代模拟软件的应用，以研究纳米结构氮化物材料的结构缺陷。

The advanced scanning electron microscopy (SEM) technique of electron backscatter diffraction (EBSD) provides information on the structural properties of materials rapidly and non-destructively with a spatial resolution of tens of nanometers. In particular, the interpretation of the acquired EBSD patterns allows crystallographic orientation, crystal structure and strain distribution across a sample to be mapped. Such information is derived from EBSD patterns acquired for each point on a map. An EBSD pattern comprises overlapping Kikuchi bands which are projections of the planes of the crystal under investigation. Presently commercial software mainly exploits the position of these bands to determine crystallographic information. The application of the EBSD technique could be significantly expanded if subtle changes in the intensity of the Kikuchi bands are exploited. This may be achieved by comparing experimental EBSD patterns with many-beam dynamical simulated patterns. To date, in collaboration with colleagues at Bruker Nano, we have demonstrated that it is possible to map anti-phase domains in GaP and have determined the polarity of GaN nanorods. This project will expand on this work to enable for example the orientation, crystal structure and polarity of arrays of nanorods to be mapped. It will also develop and explore the application of new direct electron detectors and next generation simulation software to investigate structural defects in nanostructured nitride materials.