Bandgap tuning of C3N monolayer: A first-principles study

The newly found graphene-like material C3N exhibits great potential in a variety of important applications, due to its unique topological and electronic structures. To extend the utilization, a crucial challenge is to make its intrinsic bandgap (1.03 eV) tunable. Here we performed first-principles calculations to investigate the band structure variations of C3N monolayer under various surface modification treatments, including defect engineering, surface decoration and substitutional doping. Results show that those treatments can induce impurity states, orbital rehybridization, and n- or p-type doping simultaneously, and therefore enable effective band structure adjustment. Importantly, some linear relationships between the bandgap and doping concentration are revealed, paving the way for precise control of C3N bandgap.