纤锌矿结构ZnO/Mg_xZn_(1-x)O量子阱中带间光吸收的尺寸效应和三元混晶效应  

Size and ternary mixed crystal effects on interband absorption in wurtzite ZnO/Mg_xZn_(1-x)O quantum wells

作　　者：谷卓[1] 班士良[1] 

机构地区：[1]内蒙古大学物理科学与技术学院,呼和浩特010021

出　　处：《物理学报》2014年第10期372-377,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61274098)资助的课题~~

摘　　要：对于纤锌矿结构ZnO/MgxZn1-xO有限深单量子阱结构,考虑内建电场、导带弯曲及材料掺杂对实际异质结势的影响,利用有限差分法和自洽法数值求解Schr?dinger方程和Poisson方程,获得电子(空穴)的本征能级和本征波函数.进而,采用费米黄金法则讨论带间光吸收的尺寸效应和三元混晶效应.结果表明:三元混晶材料MgxZn1-xO中Mg组分的增加会增强垒层和阱层的内建电场强度,使得电子(空穴)平均位置靠近左(右)垒,导致带间跃迁吸收峰呈指数减小且发生蓝移;ZnO/MgxZn1-xO量子阱带间跃迁吸收峰随阱宽增大而减小,吸收峰发生红移.所得结果可为改善异质结构材料和器件的光电性能提供理论指导,以期获得实际应用所需的光学吸收频谱和波长.Adopting a numerical method of solving self-consistently the Schrodinger equation and Poisson equation, the eigenstates and eigenenergies of electrons （holes） in a two-dimensional electron-hole gas are obtained for wurtzite asymmetric ZnO/MgxZn1-xO single quantum wells （QWs）. In our computation, a realistic heterostructure potential is used, in which the influences from energy band bending, material doping and the built-in electric field induced by spontaneous and piezoelectric polarizations are taken into account. Furthermore, based on the Fermi＇s golden rule, the optical absorptions of electronic interband transitions in QWs, and their size and ternary mixed crystal effects are discussed. The results indicate that the increase of the Mg component in MgxZn1-xO enhances the build-in electric field, which forces electrons （holes） to approach to the left （right） barrier. This causes the interband transition absorption peak to decrease exponentially and to be blue-shifted. For different widths of QWs, the calculated results show that absorption peak decreases and transition energy shows a red shift with the increase of well width. The above conclusions are expected to give a theoretical guidance for improving the opto-electronic properties of materials and devices made of heterostructures with suitable optical absorption spectra and wave lengths.

关 键 词：ZNO MgxZn1-xO量子阱 带间光吸收 三元混晶效应 尺寸效应 

分 类 号：O471.1[理学—半导体物理]