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

电子背散射衍射(EBSD)的先进扫描电子显微镜(SEM)技术以几十纳米的空间分辨率快速、非破坏性地提供了材料结构性质的信息。特别是，对获得的EBSD图案的解释允许绘制样品上的晶体取向、晶体结构和应变分布。这样的信息是从为地图上的每个点获取的EBSD图案中获得的。EBSD图案包括重叠的菊池带，这些带是所研究的晶体平面的投影。目前，商业软件主要利用这些带的位置来确定结晶学信息。如果利用菊池带强度的细微变化，EBSD技术的应用可能会显著扩大。这可以通过将实验EBSD图案与多光束动态模拟图案进行比较来实现。到目前为止，我们已经与Bruker Nano的同事合作，证明了在GaP中映射反相域是可能的，并已经确定了GaN纳米棒的极性。该项目将在这项工作的基础上扩展，例如，能够绘制纳米棒阵列的取向、晶体结构和极性。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.