受限激子基态能量量子尺寸效应有关问题的探讨

在有效质量近似模型和实验数据的基础上，以CdS和CdSe小量子点系统为研究对象，分别在强受限区域和弱受限区域，分析有效质量、介电常数、势垒高度等因素对受限激子基态能谱量子尺寸效应的影响．分析发现：对于处在不同环境的量子点系统，考虑其空穴的有效质量的不同对激子基态能量的动能项进行修正是十分必要的，但仅仅考虑这个因素不能从根本上改善理论结果使其与实验结果符合．对于介电常数较小的CdS和CdSe这种小量子点，库仑相互作用能的贡献也是十分重要的，并且在强受限区域对激子基态能量曲线形状的修正起了关键作用．对于CdS和CdSe这种小量子点，把库仑项忽略或作为微扰项来处理会引起较大误差．分析还发现势垒高度引起的束缚能的变化也是影响激子的基态能量的重要因素之一．

An Investigation of the Factors Affecting Quantum Size Effects of the Confined Exciton Ground State Energy in the Semiconductor Quantum Dots

The investigation of the factors affecting quantum Size effects of the confined exciton ground state energy in the Semiconductor Quantum Dots is based on the effective mass approximation (EMA) model and the experimental data. Confined exciton ground state energy in small CdS and CdSe dots systems are compared with experiment as a function of the dots radii. The factor of the dielectric constant affects Coulomb interaction energy of the system, and the factor of different effective masses affects only kinetic energy of the system while the height of the wall of the dot affects confinement energy of confined exciton, These are the important factors affecting confined exciton ground state energy. Among them, the Coulomb interaction energy is more important for fitting to experimental results of these small dots in the strong-confinement regime.