混相ZnO/ZnMgO多量子阱中电子子带间跃迁光吸收

Optical Absorption of Electron Intersubband Transition in Multi-Quantum Wells of ZnO/ZnMgO with Mixed Phases

考虑内建电场的作用,讨论ZnO/Zn1-xMgxO多量子阱(MQW)阱间耦合、尺寸和三元混晶效应对电子子带间跃迁光吸收的影响。利用有限差分法自洽求解导带中电子的Schrodinger方程和Poisson方程,获得MQW体系电子在基态、第一激发态、第二激发态能级和相应的波函数。采用费米黄金法则分别求出纤锌矿和闪锌矿两种结构子带间跃迁光吸收系数,并采用权重模型,拟合两种结构在0.37<x<0.62的混相区间光吸收系数。结果表明:在内建电场的作用下,量子阱数目(Nqw)、尺寸和混晶组分可有效调节MQW结构的光吸收系数,提高光电器件的光吸收效率。光吸收系数峰值随着Nqw的增加先发生红移然后蓝移,随着阱宽和组分的增加而发生蓝移。所得结果可为红外光电器件的制备和相关实验提供参考。

Taking into account of the built-in electric field(BEFs),this paper discusses emphatically the influence of inter-well coupling,size and ternary mixed on optical absorption of electron intersubband transitions in ZnO/Zn1-xMgxO multi quantum wells(MQWs).Using the finite difference method,the energy levels of the ground,first excited,second excited states and their corresponding wave functions of electrons in conduction band are self-consistently obtained by solving the Schrodinger equation and Poisson equation.The intersubband optical absorption coefficients(IOACs) of wurtzite and zinc-blende structures are calculated by the Fermi-golden rules and fitted by a weight model proposed by our group in the scope of mixed phases for 0.37<x<0.62.The results show that under the influence of BEFs,the number of quantum wells(Nqw),size and mixed crystal components can effectively modulate IOACs to improve the efficiency of photoelectric absorption in MQWs.The peak positions of IOACs appear red shifts first and then blue shifts with increas of Nqw,but blue shifts occur with increase of well width and Mg composition.Our results are helpful for infrared photoelectric device design and related experiments.