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 struct ure in cubic GaxIn1-xAsySb1-y lattice-matched to GaSb and InAs. Our calcula tions are based on the empirical pseudopotential formalism within the virtu al 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 al loy compositions x. Moreover, we find that at Ga concentrations (x less tha n 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 fo r the choice of substrate in the composition range 0-1 and hence for the de termination of the lattice-matching conditions for GaxIn1-xAsySb1-y quatern ary materials. (C) 1999 Elsevier Science B.V. All rights reserved.