Ab initio study of structural, electronic and optical properties of Be-doped CdS, CdSe and CdTe compounds

Full-potential linearized augmented plane wave plus local orbitals (FP-LAPW+lo) method within density functional theory (DFT) has been utilized to calculate structural, electronic and optical properties of Be-doped CdS, CdSe and CdTe compounds with the dopant concentration x in the range 0≤x≤1. For the contribution of exchange-correlation potential, we used Wu-Cohen generalized gradient approximation (GGA) to calculate structural parameters, whereas both Wu-Cohen and Engel-Vosko GGA have been applied to calculate electronic structure of the materials. Only a slight deviation from Vegard's law has been observed for the calculated lattice constants and bulk moduli of the alloys. Structural and chemical factors that affect the band-gap bowing of these semiconductor alloys have been estimated and discussed. Density of states curves and charge density maps have been calculated and analyzed. Lastly, optical properties of both binary and their related ternary alloys have been discussed in terms of the calculated dielectric function. The resultant optical parameters are compared with the available experimental data and other calculations.