Heterostructural bilayers of graphene and molybdenum disulfide: Configuration types, band opening and enhanced light response

The properties of graphene absorption on graphene-like material can be modulated by the stacking arrangement. Here, we propose a "least squares" classification method for analyzing configuration types of graphene/molybdenum disulfide heterobilayers (G/MoS2 HBLs) while binding energy, electronic structure and optical absorption of G/MoS2 HBLs are investigated via first principles calculations. Owing to the lattice mismatch, no traditional AA and AB stacking exist but AA- and AB-stacking-like configurations have been found. Paradoxically, AB-stacking-like configuration, generally as the most stable stacking sequence, does not correspond to the relaxed structure. We interpret this paradox in terms of graphene corrugation. A detailed analysis of the electronic structure indicates that bandgaps of all configurations types (types of G/MoS2 HBLs) are opened and tunable under the different interlayer distance. Furthermore, compared with monolayer MoS2, G/MoS2 HBLs display an enhanced light response, a promising feature for photocatalytic applications. (C) 2014 Published by Elsevier Ltd.