摘要
用有效质量理论研究了GaAs/Ga_(1-x) Al_xAs[111]超晶格在外加电场下的电子结构.具体计算了超晶格的子能带色散关系曲线,子能级随外加电场的变化,并且计算了k_u=0的光跃迁矩阵元平方随电场的变化.与零电场情况相比,发现在k_u≠0处子能带的二重简并解除.随电场的增大,△n=0的跃迁减小,而△n≠0的跃迁增大.考虑单轴压力效应后,轻空穴和重空穴的能级位置发生下降和上升.
The electronic structures of [111]-oriented GaAs/Ga_(1-x)Al_xAs superlattices underelectric field are investigated by the effective mass theory.Subband dispersion cu-rves are calculated, and compared with that of the [001J-oriented superlattice. Thevariations of subband energy levels and optical matrix elements at R_(11)=0 as functi-ons of eletric field are obtained.The double degeneracy of subband at R_(11)≠0 isremoved under electric field. With increasing of the electric field,the optical tra-nsitions of △n=0 decrease and that of △n≠0 increase. Under an uniaxial stressalong the growth direction, the energy levels of the heavy and light hole shift upand down, respectively, but the optical transitions under electric field are not chang-ed for R_u=0.
