Research on the Preparation and Spectral Characteristics of Graphene/TMDs Hetero-structures

The Van der Waals (vdWs) hetero-structures consist of two-dimensional materials have received extensive attention, which is due to its attractive electrical and optoelectronic properties. In this paper, the high-quality large-size graphene film was first prepared by the chemical vapor deposition (CVD) method; then, graphene film was transferred to SiO₂/Si substrate; next, the graphene/WS₂ and graphene/MoS₂ hetero-structures were prepared by the atmospheric pressure chemical vapor deposition method, which can be achieved by directly growing WS₂ and MoS₂ material on graphene/SiO₂/Si substrate. Finally, the test characterization of graphene/TMDs hetero-structures was performed by AFM, SEM, EDX, Raman and PL spectroscopy to obtain and grasp the morphology and luminescence laws. The test results show that graphene/TMDs vdWs hetero-structures have the very excellent film quality and spectral characteristics. There is the built-in electric field at the interface of graphene/TMDs heterojunction, which can lead to the effective separation of photo-generated electron-hole pairs. Monolayer WS₂ and MoS₂ material have the strong broadband absorption capabilities, the photo-generated electrons from WS₂ can transfer to the underlying p-type graphene when graphene/WS₂ hetero-structures material is exposed to the light, and the remaining holes can induced the light gate effect, which is contrast to the ordinary semiconductor photoconductors. The research on spectral characteristics of graphene/TMDs hetero-structures can pave the way for the application of novel optoelectronic devices.