Atomic Layer Deposition of ZnO Thin Film on Surface Modified Monolayer MoS2 with Enhanced Photoresponse

Monolayer MoS2 was grown on a sapphire substrate by CVD, and then transferred to a silicon wafer substrate. The morphology and crystalline of the MoS2 were characterized by AFM, SEM, and XRD. After perylene-3,4,9,10-tetracarboxylic acid (PTCA) surface treatment on the MoS2, a continuous layer of ZnO thin film was deposited. Finally, the photoresponse of both ZnO and ZnO/MoS2 thin films was investigated, and the ZnO/MoS2 thin film showed enhanced photoresponse over pure ZnO thin film. The higher response of ZnO/MoS2 heterostructure could be attributed to the effective charge transfer between ZnO and MoS2 surface and the re-absorption of light photon resulting in the production of electron-hole pairs.