Synthesis and Photoresponse of the Graphene-MoS2 in-plane Heterostructures

The heterostructures of two-dimensional materials offer a possibility to create high performance electronic and optoelectronic devices. Here, we present the construction of both the stacked and in-plane Graphene-MoS2 heterostructures directly during CVD growth. Exfoliated or patterned CVD-grown graphene were prepared on the 300 nm SiO2/Si substrate in advance. Using the seed-assisted method, different kinds of seeds were chosen to synthesize the stacked or in-plane Graphene-MoS2 heterostructures. Using the F16CuPc molecule as a seed, which can stick on the graphene surface under the growth temperature, the MoS2 monolayer was obtained on top of the graphene to achieve the construction of a stacked Graphene-MoS2 heterostructure. For an in-plane Graphene-MoS2 heterostructure, which can only be constructed by direct growth, we use the PTAS promoter as a seed, which prefers to stay on the SiO2/Si substrate out of the graphene. Then, the MoS2 monolayer was grown out from the edge of graphene to obtain the in-plane Graphene-MoS2 heterostructure, which was confirmed by AFM, Raman, PL and electric measurements. Furthermore, the photocurrent from the in-plane Graphene-MoS2 junction was measured and a high performance photoresponse device was achieved.