State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China ; Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney 2006, Australia.
School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney 2052, Australia.
Nanoscale Res Lett. 2014 May 30;9(1):278. doi: 10.1186/1556-276X-9-278. eCollection 2014.
The effect of Sb spray prior to the capping of a GaAs layer on the structure and properties of InAs/GaAs quantum dots (QDs) grown by molecular beam epitaxy (MBE) is studied by cross-sectional high-resolution transmission electron microscopy (HRTEM). Compared to the typical GaAs-capped InAs/GaAs QDs, Sb-sprayed QDs display a more uniform lens shape with a thickness of about 3 ~ 4 nm rather than the pyramidal shape of the non-Sb-sprayed QDs. Particularly, the dislocations were observed to be passivated in the InAs/GaAs interface region and even be suppressed to a large extent. There are almost no extended dislocations in the immediate vicinity of the QDs. This result is most likely related to the formation of graded GaAsSb immediately adjacent to the InAs QDs that provides strain relief for the dot/capping layer lattice mismatch.
81.05.Ea; 81.07.-b; 81.07.Ta.
通过横截面高分辨率透射电子显微镜（HRTEM）研究了在分子束外延（MBE）生长的 GaAs 层上进行 Sb 喷雾对 InAs/GaAs 量子点（QD）结构和性能的影响。与典型的 GaAs 覆盖的 InAs/GaAs QD 相比，Sb 喷雾 QD 显示出更均匀的透镜形状，厚度约为 3 ～ 4nm，而不是未进行 Sb 喷雾的 QD 的金字塔形状。特别地，观察到位错在 InAs/GaAs 界面区域被钝化，甚至在很大程度上被抑制。在 QD 的紧邻区域几乎没有扩展位错。这一结果很可能与紧邻 InAs QD 形成的梯度 GaAsSb 有关，该 GaAsSb 为点/覆盖层晶格失配提供了应变释放。
81.05.Ea；81.07.b；81.07.Ta.
