In this work, the band offsets at the Ga 0.5 In 0.5 P/Al x Ga 0.5Ϫx In 0.5 P heterojunction lattice matched to ͑001͒ GaAs was calculated over the whole range of aluminum composition from xϭ0.0 to 0.5 using the first-principles pseudopotential method with virtual crystal approximation. The valence band offset, VBO, varies with x as VBOϭ0.433x eV, while the inferred conduction band offset CBO at ⌫ minimum ͑band-gap difference minus the valence band offset͒ varies in x as CBO ⌫ ϭ0.787x eV. Our results are in good agreement with the experimental data.

The first-principles pseudopotential method combined with virtual crystal approximation is used to calculate band offsets at the In0.53(AlzGa1−z)0.47As/In0.52Al0.48As (001) heterostructures lattice matched to an InP substrate. It is found that the valence-band offset (VBO) varies with respect to the aluminum composition as VBO=0.18–0.16z–0.02z2 eV, while the conduction-band offset (CBO) varies as CBO=0.51–0.33z–0.18z2 eV. Our results are in good agreement with the experimental data.