Substrate effect on the electronic structure in Ga_xIn_(1-x)As_ySb_(1-y)/GaSb and Ga_xIn_(1-x)As_ySb_(1-y)/InAs

摘要

We present a theoretical study of the substrate effect on electronic structure in cubic Ga_xIn_(1-x)As_ySb_(1-y) lattice-matched to GaSb and InAs. Our calculations are based on the empirical pseudopotential formalism within the virtual crystal approximation where the effect of disorder is taken into account. We show that the electronic band structure of the quaternary alloy Ga_xIn_(1-x)As_ySb_(1-y) is altered by the change of substrate for the entire range of alloy compositions x. Moreover, we find that at Ga concentrations (x<=0.8), the ionicity is less important when Ga_xIn_(1-x)As_ySb_(1-y) is lattice-matched to GaSb instead of InAs. The information will be useful for the choice of substrate in the composition range 0-1 and hence for the determination of the lattice-matching conditions for Ga_xIn_(1-x)As_ySb_(1-y) quaternary materials.