Band Edges Engineering of 2D/2D Heterostructures: The C3N4/Phosphorene Interface

We investigate the interface between carbon nitride (C3N4) and phosphorene nanosheets (P‐ene) by means of Density Functional Theory (DFT) calculations. C3N4/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. Carbon nitride and phosphorene are layered materials forming a van der Waals heterojunction. Hybrid DFT calculations show how the phosphorene thickness determines the band alignment at the junction, passing from quasi‐staggered (thin limit) to straddling (thicker films). This allows tuning the photocatalytic and electronic properties of the composite.