Fig. 2
From: Direct Observation of High Photoresponsivity in Pure Graphene Photodetectors
Optical characteristics of our pure graphene photodetector. a Time-dependent photocurrent measurements of sample A with a back-gate bias voltage of V G = − 1V when optically pumped in the visible range (532 nm). The photodetector shows high photoresponses of approximately 1.15 AW−1 under the biased condition at room temperature. b The response time of the measured in one period of modulation with the laser illumination. c Photoresponse dependence on the laser spot size. d A schematic illustration of the positive charge accumulation at the interface of Si/SiO2 under light illumination without source-drain voltage bias, which effectively changes the back-gate voltage and induces a photocurrent