Structural, electronic and thermodynamic properties of wide band gap MgxZn1 - xO alloy

Structural, electronic and thermodynamic properties of a wide band gap semiconductor alloy MgxZn1 - xO have been studied using ab initio method. Calculations have been made using full potential linearized augmented plane wave (FP-LAPW) method within the framework of density functional theory (DFT). For exchange-correlation energy and corresponding potential, generalized gradient approximation (GGA) by Perdew-Burke-Ernzerhof (PBE) and Engel-Vosko (EV) have been used. We analyze composition effect on lattice constants, bulk modulus, band gap and effective mass of the electron. It is observed that bulk modulus and band gap depend non-linearly on alloy composition x, whereas lattice constants and cohesive energy follow Vegard's law. Using the approach of Bernard and Zunger [J.E. Bernard, A. Zunger, Phys. Rev. B 34 (1986) 5992.], the microscopic origin of the gap bowing is also elucidated. It is concluded that the energy band gap bowing is primarily due to chemical charge-transfer effect. Contribution of volume deformation and structural relaxation to the gap bowing parameter is found to be very small. Thermodynamic stability of MgxZn1 - xO was also studied. © 2006 Elsevier B.V. All rights reserved.