发表机构
Japan Fine Ceramics Center; Mie University; Ceramic Forum Co., Ltd（日本精细陶瓷中心; 三重大学; 陶瓷论坛有限公司）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用相衬显微镜，通过明暗衬度排列逆时针旋转90°确定GaN穿透刃位错的Burgers矢量方向，并经TEM验证，提供了一种无损光学方法。
AI 中文摘要
相衬显微镜能够快速、无损地观察GaN中的穿透位错，但位错衬度与Burgers矢量之间的关系尚未建立。在此，我们证明可以通过相衬显微镜图像中明暗衬度的排列来确定GaN中穿透刃位错的面内Burgers矢量方向。该关系首先在氨热法生长的GaN中的穿透刃位错上建立，其Burgers矢量通过X射线形貌术独立确定，随后应用于氢化物气相外延生长的GaN。由相衬预测的Burgers矢量通过弱束暗场透射电子显微镜和大角度会聚束电子衍射得到验证。对于所检查的穿透刃位错，从暗衬度最小值到亮衬度最大值的方向逆时针旋转90°所得方向与Burgers矢量方向一致。基于光弹效应的分析进一步表明，相衬主要反映位错周围两个面内法向应变分量εxx + εyy之和。这些结果表明，相衬显微镜可用作确定GaN中穿透刃位错面内Burgers矢量方向的无损光学方法。
英文摘要
Phase-contrast microscopy enables rapid, nondestructive observation of threading dislocations in GaN, but the relationship between dislocation contrast and the Burgers vector has not been established. Here, we demonstrate that the in-plane Burgers-vector direction of threading edge dislocations in GaN can be determined from the arrangement of bright and dark contrast in phase-contrast microscopy images. The relationship was first established for threading edge dislocations in ammonothermal GaN whose Burgers vectors were independently determined by X-ray topography and was subsequently applied to hydride vapor phase epitaxy-grown GaN. The Burgers vector predicted from the phase contrast was verified by weak-beam dark-field TEM and large-angle convergent-beam electron diffraction. For the threading edge dislocations examined, the direction obtained by rotating the direction from the minimum of the dark contrast to the maximum of the bright contrast by 90° counterclockwise coincided with the Burgers-vector direction. Analysis based on the photoelastic effect further suggests that the phase contrast primarily reflects the sum of the two in-plane normal strain components, εxx + εyy, around the dislocation. These results demonstrate that phase-contrast microscopy can be used as a nondestructive optical method for determining the in-plane Burgers-vector direction of threading edge dislocations in GaN.
