Substrate effect on the electronic structure in GaxIn1-xAsySb1-y/GaSb and GaxIn1-xAsySb1-y/InAs

We present a theoretical study of the substrate effect on electronic structure in cubic GaxIn1-xAsySb1-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 GaxIn1-xAsySb1-y is altered by the change of substrate for the entire range of alloy compositions x. Moreover, we find that at Ga concentrations (x less than or equal to 0.8), the ionicity is less important when GaxIn1-xAsySb1-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 GaxIn1-xAsySb1-y quaternary materials. (C) 1999 Elsevier Science B.V. All rights reserved.