Investigation on Sb distribution for InSb/InAs sub-monolayer heterostructure using TEM techniques
Investigation on Sb distribution for InSb/InAs sub-monolayer heterostructure using TEM techniques
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DOI：
10.1088/1361-6528/ab4751
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发表时间：
2019-10
期刊：
影响因子：
3.5
通讯作者：
A. Khan;M. Herrera;N. Fernández-Delgado;D. Reyes;J. Pizarro;E. Repiso;A. Krier;S. Molina
中科院分区：
文献类型：
--
作者：
A. Khan;M. Herrera;N. Fernández-Delgado;D. Reyes;J. Pizarro;E. Repiso;A. Krier;S. Molina
InSb/InAs亚单层（SML）纳米结构（如SML量子点）与其对应的Stranski-Krastanov纳米结构相比提供更尖锐的发射光谱、更好的模式增益和更大的调制带宽。本文利用透射电子显微镜（TEM）技术分析了用迁移增强外延生长的SML InSb层中Sb的分布。通过在002暗场条件下的衍射对比度和通过原子柱分辨的高角度环形暗场扫描TEM对材料的分析揭示了具有稀缺的富Sb InSbAs团聚体的低Sb含量InSbAs连续层的存在。通过这两种技术得到的强度分布点锑偏析在生长过程中。使用Muraki偏析模型对这种偏析进行了量化，获得了朝向生长方向的0.81的高偏析系数R。讨论了Sb在InAs表面上的SML沉积导致的连续InSbAs润湿层的形成。
InSb/InAs sub-monolayer (SML) nanostructures such as SML quantum dots offer sharper emission spectra, a better modal gain and a larger modulation bandwidth compared to its Stranski–Krastanov counterpart. In this work, the Sb distribution of SML InSb layers grown by migration enhanced epitaxy has been analyzed by transmission electron microscopy (TEM) techniques. The analysis of the material by diffraction contrast in 002 dark field conditions and by atomic column resolved high angle annular dark field-scanning TEM reveal the presence of a low Sb content InSbAs continuous layer with scarce Sb-rich InSbAs agglomerates. The intensity profiles obtained by both techniques point to Sb segregation during growth. This segregation has been quantified using the Muraki segregation model obtaining a high segregation coefficient R of 0.81 towards the growth direction. The formation of a continuous InSbAs wetting layer as a result of a SML deposition of Sb on the InAs surface is discussed.