Robust band gaps in the graphene/oxide heterostructure: SnO/graphene/SnO.

The applicability of graphene in nanoscale devices is somewhat limited because of the absence of a finite band gap. To overcome this limitation of zero band gap, we consider vertically-stacked heterostructures consisting of graphene and SnO knowing that two-dimensional SnO films were synthesized recently. Calculations based on density functional theory find that the oxide monolayer can induce a notable band gap in graphene; 115 meV in SnO/graphene/SnO heterostructures. Additionally, the band gap of graphene can be maintained under a relatively high electric field (≈109 V m-1) applied to the heterostructures because of the electrostatic screening effect of the oxide layer. The calculated results suggest the relative superiority of the graphene/oxide heterostructures over graphene/BN heterostructures for the nanoscale devices based on graphene.