Van der Waals heterostructure of graphene Defected&Doped X(X = Au, N) composite ZnO monolayer: A First Principle study

GGA + U(Zn 3d = 10eV, O 2p = 7eV) and van der Waals correction methods (DFT-D2) were used to calculate the surface structural, electronic and optical properties of ZnO composite graphene (Z-G) system via first-principles. The binding energy and Bader charge transfer are calculated. When the composite site is at the top site and the interlayer distance is 2 Å, the ZnO composite graphene (Z-G) interface is the most stable, the energy value is 2.86eV. The Dirac point remained unchanged after intrinsic graphene composite ZnO, indicating that the interaction between intrinsic graphene and ZnO did not affect the excellent electrical conductivity of graphene. By studying the energy band, density of states, and optical properties of ZnO in graphene (ZGC-V) composite ZnO, Au and N doped graphene (ZGC-Au and ZGC-N) composite ZnO. It is found that doped and defected graphene composite ZnO the Dirac points disappeared, the bandgap value is 0.441eV, 0.831eV and 0.203eV, respectively. Electron-hole pair is well separated at the interface of doped and defected graphene composite ZnO. The defected and doped graphene composite ZnO lead to the blue shift phenomenon of light absorption peak, defected graphene composite ZnO absorption peak movement was the maximum of 1.64eV. The change of band gap and optical properties provides a theoretical explanation for the excellent performance of ZnO composite graphene (Z-G) in photocatalysts and ultraviolet light-emitting devices.