Investigation of structural and optoelectronic properties of ZnSi1-xGexP2 (x = 0, 0.125) compound using density functional theory

This paper presents the structural and optoelectronic behavior of ZnSiP2 compound theoretically. The calculations are performed using full potential linearized augmented plane wave method (FP-LAPW) within density functional theory (DFT) as embodied in WIEN2K code. For the accuracy of calculation, Perdew-Burke generalized gradient approximation (PBE-GGA) is used. Based on the energy bands, the forbidden band gap of ZnSiP2 was found to be 1.37 eV which is suitable for photovoltaic applications. The formation of bands are explained with the help of spectra of density of states (DOS) to determine the effect of Ge doping at Si site on the electronic structure. We have also performed the computations for ZnSi0.875Ge0.125P2. Energy dependent absorption spectra is also reported in this paper to highlight the possible utilization of these compounds in optoelectronic devices.