Empirical tight-binding simulations for nonuniform disordered GaAsSb alloy

We theoretically study the direct gap and the band-edge wavefunctions’ localization of nonuniform disordered GaAsSb alloy by using empirical tight-binding simulations. We show that the nonuniformity decreases the direct gap value of the alloy while increases its statistical scattering, leading to a larger bandgap bowing compared to the ideal random alloy case. Moreover, the localization of the band-edge hole wavefunction is also enhanced due to the nonuniformity, while the band-edge electron does not experience similar effect.