The calculations of thermodynamic and opto-electronics properties of Pb1-xCaxSe semiconducting ternary Alloys

The ab initio full potential linearized augmented plane wave (FP-LAPW) method within density functional theory was applied to study the effect of composition on the structural and electronic properties Pbl-xCaxSe temary alloys. The effect of composition on lattice parameter, bulk modulus, band gap was investigate. Deviations of the lattice constant from Vegard's law and the bulk modulus from linear concentration dependence were observed. In addition, the microscopic origins of compositional disorder were explained by using the approach of Zunger and co-workers. The disorder parameter (gap bowing) was found to be strong and was mainly caused by the chemical charge transfer effect. The volume deformation contributions for all alloys were also found to be significant, while the structural relaxation contributions to the gap bowing parameter were relatively smaller. On the other hand, the thermodynamic stability and optical properties are attempted in the calculations. The calculated refractive indices and optical dielectric constants for the parent compounds show better agreement with the known data when the Moss relation is used. Compositional dependence of the optical and electronic properties studied is also investigated.