Barrier-width effects on electronic properties of GaAsSb/GaAs quantum well structures

The barrier-width effects on electronic properties of type-II GaAsSb/GaAs quantum well (QW) structure are investigated using a self-consistent method. In a case of a low carrier density, the matrix element rapidly decreases with increasing barrier width and begins to saturate when the barrier width exceeds 150 A. The rapid decrease of the matrix element is related to the fact that the conduction-band wave function is less confined in the well with increasing barrier width. Also, the transition energy is shown to rapidly decrease with increasing barrier width because the conduction-band wave function is mostly in the barrier and the subbands decrease with increasing barrier width. On the other hand, in the case of relatively high carrier density, the transition energy and the matrix element are shown to be nearly independent of the barrier width.