Oxygen-assisted growth of monolayer MoS2 films on graphene by chemical vapor deposition

MoS 2 /graphene heterojunctions have a great potential for optoelectronic applications . Here, we demonstrate the oxygen (O 2 ) assisted growth of large-area monolayer MoS 2 films on graphene using chemical vapor deposition (CVD) technique. The introduction of O 2 has greatly improved the growth environment of MoS 2 domains as well as increased the grain size of MoS 2 from submicron to micron range. Spectroscopic results show that a monolayer of MoS 2 with high crystal quality has been deposited on the graphene. Effective charge transfer is observed in MoS 2 /graphene heterojunctions . MoS 2 is doped with different concentrations of O 2 in situ by optimizing its flow rates. The photodetector prepared by MoS 2 /graphene film has a good response to light. Due to the effective photoresponse of synthesized heterojunctions , these would be useful in various applications in the optoelectronic thin films and devices.