Simple effective mass model to include the effects of GAMMA - X mixing in multiquantum barriers

Abstract

An extended effective mass model is developed to account for the possibility of mixing of the electron wave function from the Γ conduction-band state to the X conduction-band state. The strength of the mixing is determined by a mixing parameter Δ in association with the assumption of a finite interface thickness. For a simple quantum well, the model Δ compares favorably with more complicated empirical pseudopotential models, featuring complete descriptions of the band structure. A multiquantum barrier (MQB) has been designed. Using the single-band effective mass approximation model, for use in visible laser diode structures for enhanced electron confinement, it is clear that within the limitations of the model when mixing effects are accounted for, the degradation in performance is negligible. The MOB design compared with a single barrier of equivalent thickness shows a doubling of the electron reflection coefficient.