Electronic band structures and optical properties of 2D XOF (X = Ga or In) oxyfluoride monolayers using density functional theory and GW approximation

Abstract

The class of two-dimensional oxyfluoride monolayers is currently considered one of the most attractive nanomaterials for enhancing design and pushing the limits of different cutting-edge technologies. Two-dimensional semiconductor materials are the most promising systems for various applications in optoelectronic devices because they have a unique optical properties. We continue in this way by investigating the GW band structures and optical properties of unique 2D XOF (X = Ga or In) oxyfluoride monolayers, involving absorption, conductivity, refractive index, and dielectric function. We find no imaginary frequencies in the computed phonon spectra, indicating that these systems are dynamically stable. Furthermore, GaOF and InOF stay stable for temperatures T ≤ 840 K. The band gap of GaOF obtained with the single shot (G0W0) is larger than the band gap energy Eg of InOF. Where the direct band gap energies of GaOF and InOF are 6.1 eV and 4.8 eV, respectively. Our GW(PBE) numerical simulations demonstrate that the GaOF monolayer moves transparent once the frequency of the incoming light exceeds the plasma frequency (35.00 eV). Furthermore, InOF switches transparently once the incident light frequency exceeds the plasma frequency ∼ 35.00 eV. Interestingly, we obtain that these 2D sheets have a strong absorption coefficient in the range of ∼ 3.00–60.00 eV. They are emerging as a potential for the building blocks of the nano-size and ultra-thin optoelectronics of the future since they productively emit and absorb light.