ZnO quantum dots-graphene composite for efficient ultraviolet sensing

Abstract ZnO quantum dots-graphene (QDs-graphene) composite was synthesized using atomic layer deposition method. A photodetector fabricated from the ZnO QDs-graphene composite and polymers demonstrated high sensitivity to UV light with a maximum photoresponsivity of 247 A/W at 325 nm. The high photoresponsivity of this device is attributed to the high active surface to volume ratio of the ZnO QDs-graphene composite. In addition to the high photoresponsivity, fast transient response with response time on the order of tenth of milliseconds was achieved, which is attributed to high carrier transport and collection efficiency through the graphene.