Research on the electronic properties of graphene/β-Si3N4 (0001) heterojunction

The research on electronic properties of graphene/β-Si3N4(0001) heterostructure are carried out by regulating the interlayer spacing employing DTF calculations. The calculated results show that all interfaces are bonded by van der Waals (vdW) force, the configuration of Nt1 atom relative to the center of C ring is more stable with the equilibrium interlayer distance D0 of 2.908 Å and binding energy per C atom of −0.531 eV. The energy band structure is similar to the superposition of two parts of heterojunction and retains the shape of the Dirac cone with a direct band gap of 67 meV. Combined with differential density map and population analysis, it is found that 0.03 e spontaneously flow from the graphene layer to the β-Si3N4(0001) layer, results in the presence of a built-in electric field, which is conducive to the separation of electrons and holes. It is noteworthy that the band gap decreases obviously when the layer spacing gradually increases from 2.0 Å to 3.2 Å. The present results are beneficial for the designing of microelectronic devices containing vdWhs and open a window for the applications of graphene-ceramic heterojunctions.