Electronic and optical properties of two-dimensional III-nitrides from first principles

While bulk III-V semiconductors enjoy broad commercial success, 2D III-nitride materials have only recently emerged, and their applications are less well understood. Extreme quantum confinement is a promising method to shift emission wavelength into the deep ultraviolet range for sterilization applications, but in 2D GaN this is counteracted by quantum confined Stark shift due to a strong inherent polarization perpendicular to the 2D plane. Additionally, increased electron-hole interaction due to quantum confinement results in exciton binding energies much larger than those of their bulk counterparts. We report the electronic and optical properties of 2D GaN, InN, and AlN using first principles calculations. We employ density functional theory and quasiparticle corrections with the GW method, as well as the Bethe-Salpeter Equation, to produce accurate band structures, exciton binding energies, and luminescence energies. Our results provide understanding on how the reduction of the thickness to the monolayer regime affects the overall electronic and optical characteristics (Nano Letters, 10.1021/acs.nanolett.7b03003).