Reduction of persistent photoconductivity in a few-layer MoS₂ field-effect transistor by graphene oxide functionalization

We functionalized two-dimensional few-layer MoS₂ based FET with graphene oxide (GO) in order to improve its persistent photoconductivity and photoresponse time. Both pristine and GO functionalized devices show n-type semiconductor behavior with high on/off ratio exceeding ∼10⁵. The photoresponse of the GO-MoS₂ hybrid device shows almost complete recovery from persistent photoconductivity and a substantial decrease in response time from ∼15 s in the pristine MoS₂ device to ∼1 s in the GO-MoS₂ device. The reasons behind this improvement have been explored and discussed on the basis of electrostatic and photo interaction between GO and MoS₂. As GO is a strong candidate for various sensing applications, therefore this intelligent hybrid system, where GO interacts electrostatically with the underlying MoS₂ channel, has tremendous potential to add more functionalities to a pristine MoS₂ device for realizing various smart nanoscale FET-based biochemical and gas sensors for myriad applications.