纤锌矿GaN/Al_xGa_(1-x)N量子阱中激子能量  

Exciton energy in a wurtzite GaN/Al_xGa_(1-x)N quantum well

作　　者：邢德胜[1,2] 赵凤岐[1] 

机构地区：[1]内蒙古师范大学物理与电子信息学院,内蒙古呼和浩特010022 [2]集宁师范学院计算机系,内蒙古集宁012000

出　　处：《光电子．激光》2011年第4期629-634,共6页Journal of Optoelectronics·Laser

基　　金：国家自然科学基金资助项目(10964007);内蒙古自治区自然科学基金资助项目(2009MS0110)

摘　　要：考虑了纤锌矿GaN/AlxGa1-xN量子阱(QW)材料中空穴带质量和光学声子模的各向异性以及声子频率随波矢变化的效应,采用改进的LLP变分法计算了纤锌矿氮化物QW中激子的基态能量和结合能。给出了激子的基态能量和结合能随着QW宽度和Al组分变化的函数关系,并对闪锌矿和纤锌矿GaN/Al0.3Ga0.7N QW材料中激子的基态能量和结合能进行了对比。计算结果表明,纤锌矿GaN/Al0.3Ga0.7N QW材料中激子的基态能量和结合能随着阱宽的增大而降低,阱宽较小时无限深势阱中激子的基态能量和结合能量明显大于有限深势阱中的相应值,阱宽较大时这两种势阱中激子的基态能量和结合能量值趋于一致。激子的基态能量和结合能随着Al组分的增大而逐渐增大;电子-声子相互作用使激子的结合能明显降低;纤锌矿GaN/Al0.3Ga0.7N QW中激子的基态能量低于闪锌矿GaN/Al0.3Ga0.7N QW中激子的基态能量,而纤锌矿GaN/Al0.3Ga0.7N QW中激子的结合能高于闪锌矿GaN/Al0.3Ga0.7N QW中激子的结合能。Considering the anisotropy of the band mass for holes and the optical phonon mode,and the variation of phonon frequency with wave vector,the ground state energy and binding energy of an exciton in wurtzite GaN/AlxGa1-xN quantum well（QW） are calculated by a Lee-Low-Pines（LLP）variational method.The ground state energy and binding energy of a heavy-hole exciton as functions of well width and Al composition x are given.The ground state energy and the binding energy in a wurtzite GaN/Al0.3Ga0.7N quantum well are compared with those in a zinc blende quantum well.The results show that the ground state energy and binding energy of a heavy-hole exciton in a wurtzite GaN/Al0.3Ga0.7N quantum well decrease with the well width increases.The ground state energy and binding energy of a heavy-hole exciton in the infinite quantum well are significantly larger than those in the finite quantum well at smaller well width,but the corresponding values are almost the same in these two quantum wells at larger well width.Tthe ground state energy and binding energy of a heavy-hole exciton in a wurtzite GaN/AlxGa1-xN quantum well increase when Al composition x increases.The binding energy of an exciton with the effect of polaron is significantly smaller than that of a bare exciton.The ground state energy of an exciton in wurtzite GaN/Al0.3Ga0.7N quantum well is smaller than that in a zinc blende GaN/Al0.3Ga0.7N quantum well,while the binding energy of an exciton in wurtzite GaN/Al0.3Ga0.7N quantum well is larger than that in a zinc blende GaN/Al0.3Ga0.7N quantum well.

关 键 词：纤锌矿量子阱(QW) 激子 基态能量 结合能 

分 类 号：O471.3[理学—半导体物理]