Graphene/g-C3N4 bilayer: considerable band gap opening and effective band structure engineering.

The layered graphene/g-C3N4 composites show high conductivity, electrocatalytic performance and visible light response and have potential applications in microelectronic devices and photocatalytic technology. In the present work, the stacking patterns and the correlations between electronic structures and related properties of graphene/g-C3N4 bilayers are investigated systematically by means of first-principles calculations. Our results indicate that the band gap of graphene/g-C3N4 bilayers can be up to 108.5 meV, which is large enough for the gap opening at room temperature. The calculated charge density difference unravels that the charge redistribution drives the interlayer charge transfer from graphene to g-C3N4. Interestingly, the investigation also shows that external electric field can tune the band gap of graphene/g-C3N4 bilayers effectively. Our research demonstrates that graphene on g-C3N4 with a tunable band gap and high carrier mobility may provide a novel way for fabricating high-performance graphene-based nanodevices.