Electronic and optical properties of SrS nanosheet in 001 and 101 directions

Abstract

Optical and electronic properties of SrS nanosheet were investigated via density functional theory (DFT). The calculation was performed using the generalized gradient approximation (GGA) based on the WIEN2k package. Random phase approximation (RPA) was used to derive the dielectric functions. Energy band structure, density of states, dielectric function, energy loss function, optical reflectivity, absorption coefficient index of the samples were calculated for E||x and E||z electric field polarizations. The Density of state (DOS) indicates a strong hybridization between p-orbitals (S atom) and d-orbitals (Sr atom) in the valence band. The results show that the SrS nanosheets are semiconductors with indirect band gap transition. In addition, the samples have not magnetic property. The Eg of SrS nanosheet are 2.46 eV, 3.32 eV with indirect bandgap type M→Γ within the PBE-GGA and mBJ-GGA, in 001 direction and 2.83 eV, 3.82 eV with direct bandgap type Γ→Γ and indirect bandgap Γ→Δ within the PBE-GGA and mBJ-GGA, in 101 direction. The optical analysis illustrate that the first absorption peaks for these materials occur in the visible range of the electromagnetic spectrum which can be potentially attractive for applications in optoelectronics and nanoelectronics.