Analysis of Broken Symmetry in Convergent-Beam Electron Diffraction along (1120) and (1100) Zone-Axes of AIN for Polarity Determination

摘要

To accurately and easily determine the polarity of AIN using transmission electron microscopy, we compare the convergent-beam electron diffraction (CBED) patterns along the widely used (1120) and (1100) zone-axes. For the (1120) zone-axis, the diffraction disk of g = 0002 differs from that of g = 0002, while for (1100), the diffraction disks of g = 0002 and 0002 are similar. The preferential clarity of these two disks is explained using Btoch-wave dynamical theory. To further support the explanation, we compare the results of GaN case. On the basis of our analysis, we conclude that the CBED patterns of the (1120) zone-axis are more useful for accurately determining AIN polarity compared to the CBED patterns along the (1100) zone-axis.