First principle investigation of structural, electronic and optical properties of MgxZn1−xS hexagonal wurtzite ternary alloys

Abstract

Structural and optoelectronic properties of wurtzite MgxZn1−xS ternary alloys are calculated by using density functional FP-LAPW approach. Structural properties are computed with WC-GGA and optoelectronic properties with mBJ-GGA exchange-correlation potential schemes. Calculations reveal that wurtzite MgS, ZnS and their ternary alloys are direct band gap (Γ-Γ) semiconductors. Lattice constants (a, c), increases almost linearly, while bulk modulus decreases and band gap increases nonlinearly with increasing magnesium content. Optical properties of the specimens are calculated by computing the frequency responses of dielectric function, refractive index, extinction coefficient, normal incidence reflectivity, optical absorption, optical conductivity and electron energy loss function due to inelastic scattering over a wide range of frequency. Each compound is optically anisotropic in nature. Electronic transitions from S-3p to Mg-4 s,3p & Zn-5 s,4p contribute 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.