类氢杂质对In_xGa_(1-x)N/GaN量子点中激子的基态能和结合能的影响

Effects of Hydrogenic-like Impurity on Exciton Ground-State and Binding Energy in In_xGa_(1-x)N/GaN Quantum Dots

在效质量近似下,运用变分方法,考虑内建电场效应和量子点的三维约束效应,研究了类氢杂质对InxGa1-xN/GaN量子点中激子的基态能和结合能的影响。结果表明:量子点中心引入类氢杂质,量子点的结构参数(半径、高度)和In含量存在临界值,当参数大于临界值时,约束在QD中激子的基态能减小,结合能增大,激子态的稳定性增强。杂质位于量子点上界面时,激子的基态能最小,结合能最大,系统最稳定。随着杂质从量子点的上界面沿着Z轴移至下界面,激子基态能增大,结合能减小。

Concerning the domino effect of built-in electric field and the three-dimension resection, the effects of hydrogcnic-like impurity on exciton ground-state and binding energy in InxGa1-xN/GaN quantum dots （QDs） are studied by means of a variation approach within the framework of effective-mass approximation. The results show that there arc critical values on the structural parameters of the QDs （radius and height） and In content when there is hydrogenic-like impurity in the center of quantum dots. The exciton ground-state energy is rexluced, and the exciton binding energy and the stability of exciton state arc increased when the parameter is larger than the critical value. When the impurity position is on the upper interphase of ODs, the exciton ground-state energy is the lowest, the exciton binding energy the highest and the stability of exciton state the strongest. As the impurity moves to lower interphase of ODs, the ground-state energy increases and binding energy reduces.