Investigation of C60 fullerenes modified g-GaN monolayer based on DFT study

Abstract

We present a comprehensive investigation of C60 fullerenes modified g-GaN monolayer (g-GaN/C60 heterostructure) based on density functional theory (DFT). The results show that the g-GaN/C60 heterostructure is most stable when the pentagonal center of C60 molecule is adsorbed above N atom of the g-GaN monolayer. The heterostructure has a narrow direct energy gap 1.02 eV and type-II band alignment, the CBM is dominated by the C 2p orbital of the C60 molecule, as well as the VBM consists of N 2p and Ga 3d orbitals of the g-GaN monolayer. This results in the separation of electrons and holes reducing the complexation of electrons and holes, improving photoelectric conversion efficiency and photocatalytic performance of the g-GaN monolayer. In addition, the broader UV to visible-light absorption spectrum of the g-GaN/C60 heterostructure promises a potential application in photoelectric devices, especially for solar cells. The electronic and photoresponse properties of the g-GaN/C60 heterostructure applied with vertical electric field are more excellent due to better transitions of electrons from the valence band to conduction band.