First-Principles Calculations of Structural, Electronic, Optical, and Thermodynamic Properties of CdS, CdTe and Their Ternary Alloys CdS_(1-x)Te_x (0.0 ≤ x ≤ 1.0)

摘要

Using first-principle method, we investigate the structural, electronic, optical, and thermodynamic properties of the CdS_(1-x):Te_x semiconductor alloys using generalized gradient approximation for the exchange-correlation potential calculation. The ground state properties are determined for the bulk materials (CdS and CdTe) in cubic phase. Quantities such as the lattice constants and bulk modulus of interest are calculated. Detailed comparisons are made with published experimental and theoretical data and show generally good agreement. The calculated lattice constants scale linearly with composition (Vegard's law). The microscopic origins of the bowing parameter were explained using the contributions from volume deformation, charge transfer and structural relaxation approach. The refractive index and optical dielectric constant for the alloys of interest were calculated by using different models. In addition, the thermodynamic stability of the alloys was investigated by calculating the critical temperatures of alloys.