Study on Creation and Annihilation of electrons and holes in Compound Alloy semiconductors

利用CPA的扩展，从理论上研究了A1-xA* xB型对角无序化合物混合晶体的电子态。我们发现1)当势能ε b大于或小于ε a和ε a *时，混合晶体的电子能谱在组分依赖性上呈现单调变化。另一方面，2)当ε b位于ε a和ε a *之间时，电子能谱表现出较大的带隙弯曲，带隙有时变为零。我们还利用许多载流子的适当构型坐标图，研究了由深能级缺陷捕获的载流子和瞬态诱导晶格振动之间的反馈和膨胀机制的可能性。对晶格运动进行经典处理，自一致地模拟了相互作用模式的时间演化和一系列电子和空穴的非热捕获。当活化能E acte和E acth都很小时，一系列连续的非热捕获被增强，并且对于高载流子密度是可能的，然而，我们发现晶格振动振幅膨胀的可能性主要取决于少数捕获率和声子频率分布的相对宽度。

We have theoretically studied the electronic states in A1-xA* xB type compound mix crystal with diagonal disorder using an extension of CPA. We found that 1) if the potential energyεB is larger or less than bothεA andεA*, the electronic energy spectrum of the mix crystal shows monotonous change in the composition dependence. On the other hand, 2) ifεB is located betweenεA andεA*, the electronic energy spectrum shows a large band gap bowing and the band gap sometimes becomes zero. We also studied possibility of feedback and inflation mechanism among carrier captures by a deep-level defect and transient induced lattice vibrations using proper configuration coordinate diagrams for many carriers. Treating the lattice motion classically we selfconsistently simulated the time evolution of the interaction mode and a series of athermal captures of electron(s) and hole(s). When both the activation energies E acte and E acth are small, a series of successive athermal captures is enhanced and probable for high carrier densities, however, we found that thepossibility of inflation in the amplitude of the lattice vibration critically depends on the minority capture rate and the relative width of the phonon frequency distribution.