Interlayer coupling and optoelectronic properties of ultrathin two-dimensional heterostructures based on graphene, MoS2 and WS2

Unique optoelectronic properties and interlayer coupling are observed in the artificial two-dimensional (2D) heterostructures based on graphene, MoS2 and WS2 monolayers. In the graphene-WS2] heterostructures, substantial photoluminescence (PL) quenching and significant stiffening phonon modes emerge due to strong interlayer coupling. Such hybrid systems also exhibit gate-tunable current rectification behavior with a maximum rectification ratio of 103. In addition, the ambipolar properties originating from their constituents and enhanced photo-switching properties with a maximum on/off ratio of 10(3) were also observed. The MoS2-WS2 heterostructures exhibit light emission quenching of WS2 while unchanged emission of MoS2. Such a phenomenon is due to the weak interlayer coupling and inefficient charge transfer process. The enhanced optoelectronic performances suggest that the ultrathin 2D heterostructures have great potential in the future architectural design of novel optoelectronic devices.