Electronic and optical properties of ordered BexZn1−xSe alloys by the FPLAPW method

We have used the ab initio full potential linear augmented plane wave (FPLAPW) method within the local density functional theory to calculate the dielectric function and reflectivity of Be x Zn 1− x Se alloys for different compositions x = 0.0, 0.25, 0.50, 0.75 and 1.0. The calculated dielectric function and reflectivities show reasonably good agreement with the experimental data. The valence band maximum is dominated by the Se-3p states and the conduction band minimum by Zn-4s states for x = 0.0, i.e. ZnSe, and by Be-p states for x = 1.0, i.e. BeSe. Our calculations show that the direct band gap varies linearly with x .