Solar-blind ultraviolet detection based on TiO 2 nanoparticles decorated graphene field-effect transistors

Abstract

Sensitive solar-blind ultraviolet (UV) photodetectors are important to various military and civilian applications, such as flame sensors, missile interception, biological analysis, and UV radiation monitoring below the ozone hole. In this paper, a solar-blind UV photodetector based on a buried-gate graphene field-effect transistor (GFET) decorated with titanium dioxide (TiO 2 ) nanoparticles (NPs) was demonstrated. Under the illumination of a 325-nm laser (spot size ~2 μm) with a total power of 0.35 μW, a photoresponsivity as high as 118.3 A/W was obtained, at the conditions of zero gate bias and a source-drain bias voltage of 0.2 V. This photoresponsivity is over 600 times higher than that of a recently reported solar-blind UV photodetector based on graphene/vertical Ga 2 O 3 nanowire array heterojunction (0.185 A/W). Experiments showed that the photoresponsivity of the TiO 2 NPs decorated GFET photodetectors can be further enhanced by increasing the source-drain bias voltage or properly tuning the gate bias voltage. Furthermore, the photoresponse time of the TiO 2 NPs decorated GFET photodetectors can also be tuned by the source-drain bias and gate bias. This study paves a simple and feasible way to fabricate highly sensitive, cost-efficient, and integrable solar-blind UV photodetectors.