First-principles investigation of lattice constants and bowing parameter in ZnSxSe1−x alloys

First-principles calculations, by means of the full-potential augmented plane wave method using the local density approximation, were carried out for the structural and electronic properties of ZnSxSe1−x ordered alloys. We have investigated the lattice parameters, and band-gap energies. The lattice constant a exhibits a linear variation versus composition. The calculated band structures show direct band-gaps at Γ for the whole composition. We obtain a downward bowing with the strongest contribution due to the structural relaxation. The charge-transfer and volume deformation contributions to the band-gap bowing parameter are found to be negligible.