Time Dependence of Photocurrent in Chemical Vapor Deposition MoS2 Monolayer-Intrinsic Properties and Environmental Effects

We report a model for the description of a room temperature photocurrent temporal response in devices made of a chemical vapor deposition grown molybdenum disulfide monolayer. The proposed model distinguishes three components of a photoresponse that may be attributed to photoconductance and a photogating effect, where photogating involves environmental and intrinsic material contribution. We showed that each time constant obtained from the model differed by an order of magnitude and remained unaffected by changes of the environment, whereas the amplitudes behaved according to the attributed effects. Notably, the rising photocurrent signal was a useful source of information regarding the persistent photoconductivity effect. Finally, we demonstrated the versatility of our model by applying it to some previous reports on time-resolved photocurrent. Our results help to determine the optoelectronic properties of MoS2 monolayers and future photosensitive devices operating at ambient room temperature.