Highly sensitive ultraviolet photodetectors based on single wall carbon nanotube-graphene hybrid films

An ultraviolet (UV) photodetector was fabricated by depositing single wall carbon nanotubes (SWCNTs) on the surface of a graphene field-effect transistor (GFET) with buried gate electrode structure. A photoresponsivity with a value as high as 204.5 A/W was obtained under a 365-nm LED light illumination with an incident power of 3.9 mu W. The photoresponsivity of our photodetector is about four orders higher in magnitude than that of a recently reported UV photodetector, which is based on CNTs/graphene hybrid films with a photoresponsivity of 2.3 x 10(-2) A/W. With increasing the source-drain voltage of the SWCNTs modified GFET, the photoresponsivity can be further enhanced. In addition, the photoresponsivity can also be tuned by applying a small gate voltage. This work provides a simple and feasible method to create highly sensitive UV photodetectors based on all-carbon hybrid films, which are important in many applications such as military surveillance, biomedical instrumentation and environmental monitoring.