Structural, electronic and optical properties of graphene/C2P4 van der Waals heterostructures with direct bandgap and high absorption coefficient.

In this paper, we formed two graphene/C2P4 van der Waals (vdW) heterostructures (HSs) by stacking the graphene and the C2P4 monolayer which have been predicted by us. First, we investigated the stability of C2P4 monolayer, and calculated the binding energies and flat average differential charge density of two vdW-HSs. Second, we found that two graphene/C2P4 vdW-HSs are all direct semiconductors with bandgap as 0.051/0.064 eV and 0.536/0.697 eV under GGA-PBE/HSE06 functional, respectively, which provides a way to unfold the zero bandgap of graphene or let an indirect monolayer to be a relevant direct semiconductor. Additionally, two graphene/C2P4 vdW-HSs possess high absorption coefficients (16%∼18%) for the visible light and higher absorption coefficients (22%) for the near ultraviolet light, respectively. These admirable properties make two vdW-HSs as novel and potential two-dimensional materials applied on optoelectronic, electronic and photovoltaics devices. [ABSTRACT FROM AUTHOR]