Insight into the optoelectronic, and thermoelectric properties for zinc-based TMCs: First principle-based study

Abstract

In the present study, a comparative investigation was carried out related to the structural, optical, electronic, and thermoelectric nature of three different structural phases for Zinc-based binary chalcogenide material. The newly advanced TB-mBJ (Trans-Blaha modified Becke-Johnson) scheme under the framework of the well-known density functional theory was used to obtain improved and accurate electronic properties and bandgap results. The bandgap calculations show a direct band transition nature having gap values of 1.07 eV, 1.10 eV, and 2.10 eV, for the cubic Rocksalt, the hexagonal wurtzite, and the tetragonal structures of the material respectively. The valence band maxima and the conduction band minima are both positioned at the matching Γ-point revealing a direct band type of behavior in the three studied phases. The computed total and the partial density of state visualize being shifted continuously to high values along the energy axis. The linear optical parameters the dielectric constant ε(ω), the Absorption coefficient, the Energy loss function, the Reflectivity, the Refractive indices, and Extinction coefficients are resolved in detail. The static dielectric constant ε1(0) for the corresponding, α, β and γ-phases of ZnSe decreases due to the bandgap increasing from α - γ phase with an increase in the energy above zero values. The thermoelectric nature of these three different phases is well investigated and discussed in detail. The current work can be a qualitative theoretical study associated with these different phases' structural, optoelectronic, and thermoelectric behavior and their effective technological applications.