Band Edges Engineering of 2D/2D Heterostructures: The C 3 N 4 /Phosphorene Interface.

We investigate the interface between carbon nitride (C 3 N 4 ) and phosphorene nanosheets (P-ene) by means of Density Functional Theory (DFT) calculations. C 3 N 4 /P-ene composites have been recently obtained experimentally showing excellent photoactivity. Our results indicate that the formation of the interface is a favorable process driven by Van der Waals forces. The thickness of P-ene nanosheets determines the band edges offsets and the charge carriers' separation. The system is predicted to pass from a nearly type-II to a type-I junction when the thickness of P-ene increases, and the conduction band offset is particularly sensitive. Last, we apply the Transfer Matrix Method to estimate the efficiency for charge carriers' migration as a function of the P-ene thickness.