A hybrid photodetector of graphene/TiO2/inorganic PbS quantum dots for fast response

Abstract Hybrid graphene/quantum dots photodetectors have been obtained up to 10 9 A W −1 ultrahigh responsivity, but the major challenge of these architectures is the slow photoresponse speed, especially the delay time of these configurations is mostly on the second time scale. Herein, we propose a hybrid photodetector of graphene/TiO 2 films/inorganic PbS quantum dots, which bridge the gap between high sensitivity and fast response time at visible band detection. Under 635 nm light illumination, the device shows a high responsivity of 1.2 × 10 4 A W −1 , a fast decay time of 35 ms, and a specific detectivity of 1.5 × 10 12 Jones at 1 V bias. The high responsivity is ascribed to the photogating effect, and the major findings hold great promise for application in optoelectronics.