Ionicity and transverse effective charge in GaxIn1-xSb1-y quaternary alloysemiconductors

A theoretical study was carried out on the ionicity and transverse effectiv e charge (e(T)*) in GaxIn1-xAsySb1-y quaternary system lattice matched to G aSb and InAs for the zinc blende phase. The calculations are based on the p seudopotential theory under the virtual-crystal approximation. The expressi on we used for determining e(T)* provides good agreement with available exp erimental data. Attention has been paid to the influence of the alloy disor der on the studied quantities by taking into account in the calculations th e effects of compositional variations. The effect of changing the substrate is also checked. Both effects are found to have an influence on the result s. (C) 2001 Elsevier Science B.V. All rights reserved.