Characterization of InAs/GaSb superlattices grown by MOCVD with atomic resolution
Characterization of InAs/GaSb superlattices grown by MOCVD with atomic resolution
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MOCVD生长InAs/GaSb超晶格的原子分辨率表征
DOI：
10.1063/1.5115269
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发表时间：
2020-01
影响因子：
3.2
通讯作者：
Xin Li;J. Cui;Yu Zhao;Qihua Wu;Y. Teng;Xiujun Hao;Ying Chen;Jiafeng Liu;He-Zhong Zhu;Yong Huang;Yuan Yao
中科院分区：
文献类型：
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作者：
Xin Li;J. Cui;Yu Zhao;Qihua Wu;Y. Teng;Xiujun Hao;Ying Chen;Jiafeng Liu;He-Zhong Zhu;Yong Huang;Yuan Yao
利用配备了球差校正器的扫描透射电子显微镜中的高角环形暗场（HAADF）成像和电子能量损失谱（EELS），对在砷化铟（InAs）衬底上通过金属有机化学气相沉积（MOCVD）生长的砷化铟/锑化镓（InAs/GaSb）超晶格（SLs）的界面原子结构进行了分析。尽管生长温度较高，但从HAADF和EELS分析得出的界面（IF）宽度分别小于2.5个原子层（MLs）和3.8个原子层，这表明MOCVD生长的InAs/GaSb超晶格的界面质量可与分子束外延生长的相媲美。砷化镓（GaAs）型界面被认为是造成界面宽度较窄的原因。此外，研究发现，锑化镓在砷化铟上形成的界面比砷化铟在锑化镓上形成的界面更陡峭，应变也更大，这与MOCVD生长过程中特殊的气体供应和切换顺序有关。从HAADF图像推断出的应变分布表明，只有少量的锑掺入到砷化铟子层中，而有7%的铟掺入到锑化镓子层中。
High-angle annular dark-field (HAADF) imaging and electron energy loss spectroscopy (EELS) in a Cs-corrected scanning transmission electron microscope were utilized to analyze the interfacial atomic structure of InAs/GaSb superlattices (SLs) grown by metalorganic chemical vapor deposition (MOCVD) on InAs substrates. Despite high growth temperature, narrow interface (IF) widths of less than 2.5 monolayers (MLs) and 3.8 MLs were extracted from HAADF and EELS, respectively, indicating that the IF quality of MOCVD-grown InAs/GaSb SLs is comparable to those grown by molecular beam epitaxy. GaAs-type IFs are considered to account for the narrow IF width. In addition, GaSb-on-InAs IFs were found to be sharper and more strained than InAs-on-GaSb IFs, which is correlated with the special gas supply and switching sequence during MOCVD growth. The strain profile deduced from the HAADF image suggests that little Sb is incorporated into InAs sublayers and 7% In is incorporated into GaSb sublayers.