Electronic, optical, and adsorption properties of Li-doped hexagonal boron nitride: a GW approach

Abstract

This study employs quasiparticle-corrected DFT calculations to explore the electronic, optical, and surface adsorption properties of Li-doped hexagonal boron nitride (h-BN^Li) monolayers. The results reveal that Li doping introduces two defect states into the wide band gap of the monolayer, reducing the band gap from 5.73 eV to 3.72 eV at the K–Γ point of the Brillouin zone. Using the GW approach to incorporate quasiparticle energies demonstrates a distinct advantage over conventional DFT, leading to qualitative shifts in band alignment across the Brillouin zone. Additionally, we identify intragap transitions driven by these defect states, resulting in a significant red shift in the optical gap, decreasing it from 5.73 eV to 1.61 eV in the doped monolayer. Moreover, Li doping enhances the detection of carbon-based gas molecules, raising the surface adsorption energy by –0.42 eV and –0.45 eV compared to the pristine monolayer. These findings hold substantial promise for the application of h-BN^Li in electronic, optoelectronic, optical, and sensing devices, effectively subjugating the challenge posed by its wide band gap.