First-principles calculations to investigate the optoelectronic, and thermoelectric nature of zinc based group II-VI direct band semiconductors

Abstract

The electronic structure, optical, and thermoelectric properties of novel zinc-based group II-VI semiconductors are investigated using first-principles calculations based on density functional theory. The ternary type materials' structural parameters and electronic band profiles were computed with the advanced TB-mBJ potential. Our computations indicated that the materials are direct band-type semiconductors, with energy gaps of 1.65 eV for MgZnO2 and 2.54 eV for MgZnS2, respectively. If the adjacent valence band is retained, the motion linked with conduction band minima around the Fermi level would most likely reproduce the function in the band gap opening, being the major reason for the decrease in the band gap value from MgZnS2 to MgZnO2. For these materials, the estimated total density of states showed a progressive move along with the energy value. To investigate the optical transitions in these materials, linear optical characteristics such as the complex dielectric function, loss functions, absorption coefficients, reflectivity spectra, and refractive indices were computed and discussed. Furthermore, the thermoelectric properties of these materials were calculated indicating that these materials are competent for applications involving thermoelectric devices.