The Relationship Between Atomic Structure and Strain Distribution of Misfit Dislocation Cores at Cubic Heteroepitaxial Interfaces
The Relationship Between Atomic Structure and Strain Distribution of Misfit Dislocation Cores at Cubic Heteroepitaxial Interfaces
复制标题
DOI：
10.1017/s1431927617000137
复制
发表时间：
2017-03
影响因子：
2.8
通讯作者：
C. Wen
中科院分区：
文献类型：
--
作者：
C. Wen
摘要失配位错(MD)核的原子重构引起了核周围应变分布的变化。利用模拟投影势和像差校正的透射电子显微镜图像，研究了AlSb/GaAs(001)立方闪锌矿界面上的几个MD核，包括对称滑移组Lmer位错(LD)、左移滑动组LD、原子台阶滑移组LD、对称洗牌组LD和60°位错对。图像去卷积也被用于从非最佳散焦图像中恢复结构图像。以ε衬底为参考晶格，通过几何相分析得到了相应的双轴应变图：εxx(面内)和xy(面外)。结果表明，从应变图可以揭示出MD磁芯的原子结构特征。应变图应从最佳散焦图像或恢复的结构图像测量。此外，对于MD岩心，εxx应变图比εyy应变图更准确，由于动态散射的影响，试件厚度应低于临界厚度。
Abstract The atomic reconstruction of a misfit dislocation (MD) core causes change in the strain distribution around the core. Several MD cores at the AlSb/GaAs (001) cubic zincblende interface, including a symmetrical glide set Lomer dislocation (LD), a left-displaced glide set LD, a glide set LD with an atomic step, a symmetrical shuffle set LD, and a 60° dislocation pair, were studied using simulated projected potential and aberration-corrected transmission electron microscope images. Image deconvolution was also used to restore structure images from nonoptimum-defocus images. The corresponding biaxial strain maps, ε xx (in-plane) and ε yy (out-of-plane), were obtained by geometric phase analysis using the GaAs substrate as the reference lattice. The results show that atomic structure characteristics of MD cores can be revealed by the strain maps. The strain maps should be measured from optimum-defocus images or restored structure images. Furthermore, the ε xx strain map has been found more accurate than the ε yy strain map for MD cores, and the specimen thickness should be below the critical thickness due to the influence of dynamical scattering.