Density functional study of electronic, elastic and optical properties of [formula omitted] (x=0, 0.25, 0.50, 0.75, 1) alloys

Abstract

In this study, the structural, electronic, elastic and optical properties of GaAs, GaN and their ternary alloys GaAs1−xNx (x = 0.25, 0.50, 0.75) are investigated within density functional theory utilizing WIEN2K package. The calculations are performed using the exchange-correlation energy functional from Wu-Cohen GGA for the structural and elastic properties and (mBJ –LDA) functional for the electronic and optical properties. The results show the calculated lattice constants as a function of x are in the best agreement with Vegard's linear rule. In the case of electronic properties, the electronic band structures are calculated and the results show GaAs1−xNx alloys are direct band gap semiconductors with a reduction in the band gap for N concentration x = 0.25 and x = 0.50. The results also show that the minimum band gap for the considered alloys occurs for N concentrations x = 0.25. Regarding the optical properties, the imaginary and real parts of dielectric function within the random phase approximation are investigated. The major points in the imaginary part of dielectric function are identified according to the electronic band structure calculations for each concentration. Furthermore, the elastic properties of considered alloys are investigated and the elastic constants, the bulk modulus, the shear modulus, the Young's modulus, the anisotropy factor and Poisson's ratio are calculated.