Energy Bandgap of Cd1−xZnxTe, Cd1−xZnxSe and Cd1−xZnxS Semiconductors: A First-Principles Analysis Based on Tran–Blaha–Modified Becke–Johnson Exchange Potential

This paper presents a first-principles investigation of the energy bandgaps of Cd 1− x Zn x Te, Cd 1− x Zn x Se and Cd 1− x Zn x S semiconductor alloys in zinc-blende crystals. The theoretical analysis is based on the full-potential linearized augmented plane wave method within both generalized gradient and local density approximations. Tran–Blaha-modified Becke–Johnson exchange potential was invoked to accurately provide bandgaps and their bowing parameters. A moderate nonlinear dependence with average bowing parameters around b ~ 0.49 eV for Cd 1− x Zn x Te, b ~ 0.68 eV Cd 1− x Zn x S, and b ~ 0.63 eV for Cd 1− x Zn x Se was found. The origin of the nonlinearity is discussed in light of Zunger’s approach to conclude that it arises mainly from volume deformation.