论文部分内容阅读
在有效质量近似下,运用变分方法,考虑内建电场效应和量子点(QD)的三维约束效应的情况下,研究了类氢施主杂质在量子点中的位置对III族氮化物量子点中束缚激子结合能的影响。结果表明:当类氢施主杂质位于量子点中心时,对于InxGa1-xN/GaN量子点,量子点高度和In含量存在临界值,当参数大于临界值时,约束在QD中束缚激子的结合能升高,激子态的稳定性增强,提高了激子的离解温度,使人们能在较高的温度条件下观察到半导体量子点吸收谱中的激子峰。而类氢施主杂质总是使束缚在GaN/A lxGa1-xN量子点中激子的结合能升高,载流子被更强的约束在量子点中。说明对GaN/A lxGa1-xN量子点,杂质使人们能在更高温度下观察到量子点中的激子。类氢施主杂质位于量子点上界面时,束缚激子的结合能最大,系统最稳定;随着施主杂质下移,激子结合能减小,激子的离解温度下降。
Under the approximation of effective mass, by using the variational method and taking into account the built-in electric field effect and the three-dimensional constrained effect of quantum dots (QD), we have studied the effect of the position of the hydrogen-like donor impurity in the quantum dots on the group III nitride quantum dots Bound exciton binding energy. The results show that there is a critical value for the quantum dot height and the In content for the InxGa1-xN / GaN quantum dots when the hydrogen-like donor impurity is located in the center of the quantum dots. When the parameter is larger than the critical value, the binding energy of the bound excitons in the QD Increase the stability of the exciton state increased, increasing the exciton dissociation temperature, so that people can be observed at higher temperatures exciton peaks in the semiconductor quantum dot absorption spectrum. The hydrogen-like donor impurities always bind the excitons in GaN / AlxGa1-xN quantum dots with higher binding energy, and the carriers are more confined in the quantum dots. Explain that for GaN / AlxGa1-xN quantum dots, impurities allow one to observe excitons in quantum dots at higher temperatures. When the donor species of hydrogen-like donor is located at the upper interface of the quantum dot, the binding energy of the bound exciton is the largest and the system is the most stable. As the donor impurity moves down, the exciton binding energy decreases and the dissociation temperature of the exciton decreases.