闪锌矿GaN／AlGaN量子点中激子态及光学性质的研究

摘要

在有效质量近似的框架下，运用变分方法研究闪锌矿GaN／AlGaN量子点中的激子态及相关光学性质，探讨电子与空穴在量子点中的三维空间受限和有限势效应．数值计算结果显示，当量子点的尺寸增加时，量子尺寸效应对电子和空穴的影响减弱，基态激子结合能和带问光跃迁能也都降低；而当该量子点中垒层A1GaN中Al含量增加时，提高了量子点对电子和空穴的束缚作用，同时基态激子结合能和带间光跃迁能都增加．数值的理论结果与相关实验测量结果一致．%Within the framework of effective-mass approximation, exciton states confined in zinc-blende GaN/AlGaN quantum dot （QD） are investigated by a variational approach, including the three-dimensional confinement of electron and hole in the QD and the finite band offset. Numerical results show that both the exciton binding energy and the interband emission energy decrease when QD height （or radius） increases. Our theoretical results are in agreement with the experimental measurements.