Electric gating and interlayer coupling controllable electronic structure and Schottky contact of graphene/BiI_3 van der Waals heterostructure

摘要

Graphene-based van der Waals heterostructures have received tremendous interest from both fundamental and experimental studies because they can enhance the properties and expand the possibility of applications of both graphene and two-dimensional materials. Motivated by the successful synthesis of the graphene/BiI_3 heterostructure [Chang et al. Adv. Funct. Mater. 28, 1800179 (2018)]., here, we systematically investigate the electronic structure and interfacial characteristics of this material using first-principles simulations. We find that the structure of the graphene/BiI_3 heterostructure is mainly characterized by weak van der Waals interactions, which keeps the heterostructure feasible. In the ground state, the graphene/BiI_3 heterostructure forms the n-type Schottky contact with a barrier of 0.53 eV. The barriers of the Schottky contact can be adjusted by various factors, including interlayer coupling and electric gating. Both the interlayer coupling and electric gating lead to the transformation from the n-type Schottky contact to the n-type one or to the n-type Ohmic contact. These findings demonstrate that graphene/BiI_3 can be considered a promising building block for high-performance photoresponsive optoelectronic devices.