Electron delocalization of tensily strained GaAs quantum dots in GaSb matrix
Electron delocalization of tensily strained GaAs quantum dots in GaSb matrix
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GaSb 基体中张应变 GaAs 量子点的电子离域
DOI：
10.1063/1.3520669
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发表时间：
2010
影响因子：
3.2
通讯作者：
Chien
中科院分区：
文献类型：
--
作者：
Ta;Yue;L. C. Li;Y. Sung;Sheng;L. Chang;Y. Suen;Chien
研究了GaSb中II型张应变GaAs自组装量子点在14 T磁场下的磁光响应。通过沉积不同的GaAs量，改变了点的尺寸和相应的发射能量。利用抗磁位移的结果分析了不同点的载波函数范围。结果发现，随着能量的增加（点尺寸的减小），抗磁系数首先迅速上升，然后在21 μeV/T2附近饱和。 基于一个简单的计算模型，这种不寻常的趋势归因于电子逐渐溢出的量子点的润湿层，随着点变得越来越小。这种离域效应在该材料系统中由于点内的拉伸应变弛豫而增强，这使得导带边缘高于润湿层中的导带边缘。
The magneto-optical response of type-II tensily strained GaAs self-assembled quantum dots in GaSb was investigated in magnetic fields up to 14 T. By depositing different GaAs amount, the dot sizes and the corresponding emission energies were varied. We analyzed the carrier wave function extent of different dots using the diamagnetic shift results. It was found that, with the increase in the energy (the reduction in the dot size), the diamagnetic coefficient first rises quickly and then saturates at around 21 μeV/T2. Based on a simple calculation model, this unusual tendency is attributed to the electrons gradually spilling out of the quantum dot to the wetting layer as the dots get smaller. This delocalization effect is enhanced in this material system due to the tensile strain relaxation within the dots, which raises the conduction band edge over that in the wetting layer.