A first-principles research of two-dimensional AlN/C2N van der Waals heterostructure as photocatalyst

Abstract

Van der Waals (vdW) heterostructures are ordinarily employed to furnish more possibilities for two-dimensional (2D) semiconductor materials. In this work, we explore thoroughly the electronic and optical properties of AlN/C 2 N heterostructure based on first-principles. The results reveal that the heterostructure with an indirect bandgap is a semiconductor material that is stable in energy and made by vdW interaction. The AlN/C 2 N heterostructure has type-II band alignment that can availably facilitate the segregation of photogenerated carriers and prolong the longevity of the carriers, and the built-in electric field ( E int ) formed inside the heterostructure can further encourage them. The band edge position crossing the water-splitting redox potential states that the heterostructure can serve to water-splitting catalytic process, while water oxidation and reduction reactions befell in the AlN layer and the C 2 N layer, respectively. Moreover, the heterostructure has higher carrier mobility and stronger light absorption capacity in the near-ultraviolet and visible light regions compared to two monolayers. It is worth noting that the light absorption of the heterostructure has redshift under compressive biaxial strain. The work demonstrates that the 2D AlN/C 2 N heterostructure has the compelling potential to be used as an efficient water-splitting photocatalyst and used for other optical devices. • The photogenerated carriers in the type-Ⅱ AlN/C 2 N vdW heterostructure can be effectively separated under the light. • The energy band of AlN/C 2 N spans the redox potential of water, so it can be used for photocatalytic water splitting. • The heterostructure possesses higher light absorption coefficient in the near-ultraviolet and visible light regions. • AlN/C 2 N heterostructure can be used in photocatalysis and other optical fields.