The first-principles study on the graphene/MoS2 heterojunction

Graphene's Dirac point in the band structure and no current switching ratio make it hard to be used in sophisticated logic circuits. The graphene/MoS2 heterojunction, which opens the Dirac point of graphene, can solve this problem. Based on the first-principles, the most stable monolayer graphene and MoS2 were obtained through the convergence test. The accuracy of their models was verified. In addition, lattice matching mechanisms, stacking modes, electronic structures, and optical properties of the designed heterojunction structures were calculated. The graphene/MoS2 heterojunction in a lattice matching way has the lowest relative energy. The band structures of nine heterojunctions were very similar. The maximum bandgap opening of heterojunctions was 14 meV. Compared with MoS2, its absorption intensity in the visible range improved. The dielectric function of the heterojunction was not zero in the infrared range. It indicated that the absorption of infrared light by the heterojunction was stronger than that by the MoS2.