High-performance solar-blind photodetector with graphene and nitrogen-doped reduced graphene oxide quantum dots (rGOQDs)

Hybrid photodetector of graphene and reduced graphene oxide quantum dots (rGOQDs) is promising for deep-UV photodetection. However, these photodetectors are usually suffered from long response time and vacuum-required measurement environment. In this study, nitrogen-doped rGOQDs were synthesized by the improved Hummers method and DMF hydrothermal treatment approach, while DMF was used as a reducing reagent to enhance the photoresponse of rGOQDs. Hybrid photodetector with rGOQDs on graphene was fabricated using Al₂O₃ as capping layer. High photoresponsivity of 2.1 × 10⁶ V/W and response time of 0.13 s were obtained at deep-UV under ambient environment, and enhanced photoresponse was observed in solar-blind wavelength compared to normal UV light. Furthermore, the integration of rGOQDs made a great improvement for graphene transistor characteristics, with a 5-fold mobility improvement and a shift of Dirac point of 50 V. This paper provide a feasible way for the fabrication of solar-blind photodetectors with high responsivity, fast response time and ambient condition performance, which are important for the community of photodetection.