First-principles study of the electronic and optical properties of homo-doped 2D-hBN monolayer

Abstract

The two-dimensional (2D) hexagonal boron nitride (h-BN) semiconductor has a wide bandgap and is made up of boron (B) and nitrogen (N) atoms arranged in a honeycomb lattice and connected by strong covalent bonds. We use first-principles based density functional theory (DFT), hybrid functional (GauPBE), and random phase approximation to explore the electronic and optical properties of pristine and 2D-(h-BN)1-xCx, x = 11 % and 22 % (carbon homo-doped 2D h-BN) monolayers. The formation energy analysis showed that the structural stability of carbon homo-doped 2D h-BN monolayer was better than 2D-(h-BN)1-xSx, x = 11 % and 22 % (sulfur homo-doped 2D h-BN) monolayer. The estimated band gaps in the carbon homo-doped 2D h-BN system were 5.9 (pristine), 4.25 (x = 11 % C), and 2.42 (x = 0.22 % C) eV, with the band gap decreasing as the concentration of the C atom increased. The polarization was parallel to the sheet as the carbon-homo doping concentration increased, and the band edge dropped to a minimal energy level, as validated by DFT + RPA calculations. Furthermore, the presence of LFE influence the optical properties of the homo-doped 2D h-BN.