Structural and electronic properties of Zn1-xMgxSySe1-y alloys

The structural and electronic properties of Zn(1-x)g(x)S(y)Se(1-y), quaternary alloys have been investigated using the full potential-linearized augmented plane wave (FP-LAPW) method within density functional theory (DFT). We used the generalized gradient approximation (GGA) that is based on exchange-correlation energy optimization for calculating the total energy. Moreover, the Engel-Vosko GGA formalism is applied so as to optimize the corresponding potential for band-gap structure calculations. We investigated the effect of composition on lattice constant, bulk modulus and band gap. A non-linear dependence on the compositions x and y is observed for all the three properties. The energy gap E,(x, y) has been determined over the entire compositions x and y. In addition, the energy gap of zinc-blende Zn1-xMgxSySe1-y quaternary alloys in conditions of lattice matched to GaAs substrate has been investigated. (c) 2006 Elsevier B.V All rights reserved.