Direct growth of graphene-MoS2 heterostructure: Tailored interface for advanced devices

Ultrathin film heterostructures represent the main foundations of numerous modern devices. Recently, 2D materials combined into van der Waals multilayers have emerged as an appealing option to conform hetero-structures with outstanding properties while circumventing the interfacial lattice-matching constraints encountered in heteroepitaxial synthesis. Among them, the MoS2-Graphene heterostructures exhibit suitable contact properties that promote efficient charge injection and transfer. We here report on the direct synthesis of graphene films on MoS2 by Plasma Assisted CVD. We assess the influence of using Sulphur vapor during the synthesis to heal the S vacancies, both of natural origin and induced during the growth. We find that the graphene grain size increases when using S and relate this effect with the defect density of MoS2 and the interfacial conductance. The methodologies shown are intrinsically scalable and represent a step forward in the direct growth of van der Waals heterostructures for advanced devices.