Composition profiling of GaAs/AlGaAs quantum dots grown by droplet epitaxy
Composition profiling of GaAs/AlGaAs quantum dots grown by droplet epitaxy
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DOI：
10.1063/1.4897006
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发表时间：
2014-10-13
影响因子：
4
通讯作者：
Koenraad, P. M.
中科院分区：
文献类型：
--
作者：
Bocquel, J.;Giddings, A. D.;Koenraad, P. M.
液滴外延(DE)是一种可以制备III-V量子点的生长方法，其光电性质可以通过结晶条件进行精确控制。在这项工作中，结合横截面扫描隧道显微镜和原子探针层析成像技术，对GaAsAlGaAsDE量子点进行了分析。得到了不同尺寸的量子点的结构细节和定量的化学分析。大多数量子点都是纯的砷化镓，但也有一小部分量子点由于局部刻蚀而表现出高度混合。观察到高深宽比的大量子点在其上方有一个富铝的顶端。这一结构归因于DE生长封顶阶段阳离子迁移率的差异。(C)2014 AIP出版有限责任公司。
Droplet epitaxy (DE) is a growth method which can create III-V quantum dots (QDs) whose optoelectronic properties can be accurately controlled through the crystallisation conditions. In this work, GaAs/AlGaAs DE-QDs have been analyzed with the complimentary techniques of cross-sectional scanning tunneling microscopy and atom probe tomography. Structural details and a quantitative chemical analysis of QDs of different sizes are obtained. Most QDs were found to be pure GaAs, while a small proportion exhibited high intermixing caused by a local etching process. Large QDs with a high aspect ratio were observed to have an Al-rich crown above the GaAs QD. This structure is attributed to differences in mobility of the cations during the capping phase of the DE growth. (C) 2014 AIP Publishing LLC.