INAS/GAAS PYRAMIDAL QUANTUM DOTS - STRAIN DISTRIBUTION, OPTICAL PHONONS, AND ELECTRONIC-STRUCTURE
INAS/GAAS PYRAMIDAL QUANTUM DOTS - STRAIN DISTRIBUTION, OPTICAL PHONONS, AND ELECTRONIC-STRUCTURE
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DOI：
10.1103/physrevb.52.11969
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发表时间：
1995-10-15
影响因子：
3.7
通讯作者：
BIMBERG, D
中科院分区：
文献类型：
--
作者：
GRUNDMANN, M;STIER, O;BIMBERG, D
对最近用分子束外延技术制造的薄润湿层上的金字塔形 InAs/GaAs 量子点 (QD) 内部及其周围的应变分布进行了数值模拟。为了比较各向同性材料的赝晶板、圆柱体和球体内部和周围的应变分布的解析解，为理解二维、一维和零维赝晶纳米结构中的应变分布提供了指导。对于金字塔点，我们发现静水应变主要限制在量子点内；相反，部分各向异性应变是从 QD 进入势垒的。量子点中的光学声子能量经过估计，与最近的实验结果完全一致。根据应变张量的变化计算局部带隙修正。另外还考虑了压电效应。三维有效质量单粒子：使用实际约束势求解电子和空穴的薛定谔方程。由于量子点处于强约束状态，库仑相互作用可以被视为扰动。由此获得的电子结构与发光数据一致。另外还考虑了 AlAs 势垒。
The strain distribution in and around pyramidal InAs/GaAs quantum dots (QD's) on a thin wetting layer fabricated recently with molecular-beam epitaxy, is simulated numerically. For comparison analytical solutions for the strain distribution in and around a pseudomorphic slab, cylinder, and sphere are given for isotropic materials, representing a guideline for the understanding of strain distribution in two-, one-, and zero-dimensional pseudomorphic nanostructures. For the pyramidal dots we find that the hydrostatic strain is mostly confined in the QD; in contrast part of the anisotropic strain is from the QD into the barrier. The optical-phonon energies in the QD are estimated and agree perfectly with recent experimental findings. From the variation of the strain tensor the local band-gap modification is calculated. Piezoelectric effects are additionally taken into account. The three-dimensional effective-mass single-particle: Schrodinger equation is solved for electrons and holes using the realistic confinement potentials. Since the QD's are in the strong confinement regime, the Coulomb interaction can be treated as a perturbation. The thus obtained electronic structure agrees with luminescence data. Additionally AlAs barriers are considered.