Theoretical calculation of band-edge discontinuities near a strained heterojunction: Application to (In,Ga)As/GaAs

Energy-band lineups at [100] GaAs/(In,Ga)As heterojunctions are calculated using a self-consistent tight-binding treatment. We distinguish (i) the modification of bulk band structures due to strain, and (ii) a shift of one bulk structure with respect to the other, due to charge transfer across the interface. The main result is that, for a system strained to the GaAs lattice parameter, depending on the indium concentration, light and heavy holes can be localized either both in the same layer, or in the two different layers. Comparison with different experiments provides fairly good agreement.