GaAs/Al_xGa_(1-x)As超晶格束缚态电子能级结构的理论研究

Theoretical Study of Bound State Electronic Energy Level Structure in GaAs/Al_xGa_(1-x)As Superlattice

我们运用Kronig-Penney模型,研究了GaAs/AlxGa1-xAs超晶格的束缚态电子能级结构、带宽,跃迁矩随超晶格的结构参量(阱宽、垒宽和Al组分)变化关系,以及子带能量色散关系.计算结果表明:影响光跃迁频率的最大因素是阱宽,随着阱宽的增加,光跃迁频率逐渐减小;影响带宽的较大因素是垒宽,随垒宽的增大,带宽逐渐减小;超晶格结构参量对跃迁矩的影响很小;随着Al组分的增加,光跃迁频率逐渐增大;第一子能带随波矢的变化不是很明显,第二子能带随波矢变化比较明显.这些将对实验测量和器件应用有一定的参考价值和指导意义.

We investigated the electronic energy structure of the extended state in GaAs/AlxGa1-x supperlattice based on the general formalism of the Kronig-Penny model. The optical transition frequency, the bandwidth and transition moment as a function of the quantum well width, the barrier width and the composition percent of Al are obtained. In addition, the relation between energy and the wave vector is given and discussed. Our calculated results show that the most important factor that impacts the optical transition frequency is the width of well. The wider the well is, the smaller the optical transition frequency is. The most factor that affect the bandwidth is the width of barrier. The wider the well （the barrier） is, the smaller the bandwidth is. The second subband is affected more distinctly than the first subband by the wave vector. The result will be helpful to the experiments and the designing of devices.