A theoretical investigation of structural, electronic and optical properties of wurtzite BexZn1-xO ternary alloys using DFT based FP-LAPW approach

Abstract

Structural and optoelectronic properties of wurtzite BexZn1-xO ternary alloys are carried out using density functional FP-LAPW approach in association with modified Becke-Johnson (mBJ) functional. Each stable wurtzite specimen under consideration exhibits direct band gap (Γ-Γ). Nonlinear decrease in lattice constants (a, c), but increase in bulk modulus and fundamental band gap (Eg) are observed with increasing Be-concentration x. The frequency responses of dielectric function, refractive index, extinction coefficient, optical conductivity and absorption, reflectivity and energy loss function have been computed. Each wurtzite specimen is optically anisotropic and hence shows uniaxial birefringence. The electronic transitions O-2p → Be-3 s,2p & Zn-5 s,4p are responsible for the occurrence of intense peak(s) in each dielectric function spectra. The static dielectric constant, static refractive index and static reflectivity decrease, while critical point energies in each of the ε2(ω), k(ω), α(ω) and σ(ω) spectra increases with increase in band gap and vice versa.