隔离层厚度和盖层厚度对InAs/GaAs量子点应变分布和发射波长的影响

分析了量子点盖层生长过程中隔层厚度对应变分布的影响，指出隔层材料的纵向晶格常数与量子点材料的纵向晶格常数对应变分布具有重要意义.定性说明了应变因素在隔离层生长过程中对量子点高度塌陷产生的影响.讨论了当隔离层顶面与量子点高度持平后，增加盖层厚度对应变分布的影响.基于变形势理论，讨论了上述几何参数的变化对发光波长的影响，并与实验结果进行了对比.结果表明，在量子点加盖过程中，应变因素对其形貌和发光特性具有重要作用，以应变工程为基础的发射波长调控是拓展量子点波长发射范围的有效途径. 关键词： 应变工程 半导体量子点 隔离层 盖层

Effects of the thickness of spacing layer and capping layer on the strain distribution and wavelength emission of InAs/GaAs quantum dot

A systematic investigation is given about the influence of thickness of the spacing layer on the strain distribution during the capping stage of the quantum dot. The calculated results show that the mismatch between the lattice constant of the spacing layer along the growth direction and that of the quantum dot is very important for the the strain distribution. The height of the quantum dot is compressed during the capping stage, which is qualitatively interpreted form the strain distributions. When the thickness of the spacing layer equals the quantum dot, the influence of thickness of the capping layer on strain distribution is also discussed. Based on the deformation potential theory, the dependence of the emission wavelength on the thickness of the capping layer is investigated. The calculated results agree well with the experiment results. We conclude that, during the capping stage of the quantum dot, the strain is very critical for both the shape of the quantum dot and the optical characteristics; extension of the emission wavelength via quantum dot strain engineering is an effective means.