LAUSR

Abstract The gallium nitride (GaN) is a novel wide-gap semiconductor for photoelectric devices. In this paper, two 2D single-layer GaN crystal structures, called H–GaN and T–GaN, are discovered by the density functional theory calculations. The phase stability is confirmed by phonon dispersions. The sole-atom-thick crystals of H–GaN and T–GaN, has possess enlarged specific surface area than the graphene-like allotrope (g-GaN) due to the porous structures. In addition, they have indirect band gaps of 1.85–1.89 eV and the electronic structures can be further modulated by applied strains. For example, T–GaN transforms from an indirect semiconductor to a direct one due to compressed strains. Both the combination of high specific surface area and moderate band gaps make these 2D crystals potential high-efficiency photocatalysts. Our results will also stimulate the investigations on 2D GaN nano crystals with rich electronic structures for wide applications.