Enhanced photoresponsivity of the GOQDs decorated WS2 photodetector

The two-dimensional WS2 material with the capability of achieving high photoelectric characteristics has attracted more and more attention. However, it still suffers from the limited optical absorption and the lower photogenerated carrier lifetime. Here, we report a WS2 photodetector decorated by the environment-friendly and stabilized graphene oxide quantum dots (GOQDs) as hole harvesting media. Through introducing GOQD5 by a simple solution method, the photoelectric performances of the photodetector are improved efficiently. The photoresponsivity of the photodetector is increased to 12.5 mA W-1, and the detectivity is also improved to about 2.01 x 10(10) Jones. The enhanced photoresponsivity is attributed to the GOQD5-WS2 heterostructure and photogating effect of GOQD5, which can promote the separation of the photogenerated electron-hole pairs and the hole carriers trapped in GOQD5, respectively. These reasons also extend the recombination time between them. This work may provide a new approach for preparing green and environment friendly photodetector with enhanced performance.