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

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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.