用格林函数法计算量子点中的应变分布

The calculation of strain distribution in quantum dots with Green method

自组装量子点材料作为一种新型的光电材料无论在理论和实际应用都成为当今物理学界的研究热点 .由GaAs包围的InAs小岛 ,由于较大的晶格失配 (≈ - 0 0 6 7) ,应变效应在量子点的形成过程中起主导作用 .大部分计算量子点结构应变分布的方法都是基于数值解法 ,需要大量的计算工作 .给出用格林函数法推导各种常见形状量子点应变分布的解析表达式详细过程 ,讨论了弹性各向异性和形状各向异性对量子点应变分布的影响程度 .结果表明对于不同形状量子点结构中主要部分的应变分布都是相似的 。

There is considerable interest in the study of self_assembled quantum dots as one of the new optoelectronic materials in the field of physics. It is interesting in theory, and also applications. In this article, we consider the InAs islands buried in GaAs, because of large lattice mismatch (≈-0.067), which makes strain effect to be the main factor in the formation of quantum dots. Most methods for calculations of strain distribution are based on the numerical solution of quantum dots structures, which need heavy calculations work. We present a detailed process to derive an analytical formula for the strain distribution in some familiar shapes of quantum dots with Green function method, and discuss their influence on the strain distribution in quantum dots by taking into account the anisotropy of elastic properties and shape. The results showed that the strain distributions in the major part of the quantum dot structure are very similar for different shapes and that the characteristic value of the hydrostatic strain component depends only weakly on variation of the shape of quantum dots.