Self-powered high performance photodetectors based on CdSe nanobelt/graphene Schottky junctions

Self-powered photodetectors based on CdSe nanobelt (NB)/graphene Schottky junctions are fabricated and investigated. Typically such Schottky junctions exhibit good rectifying behavior without light illumination. The on/off ratio is more than 1 × 105 when the voltage changes from −1 to 1 V. Under zero bias, typically such photodetectors show high photosensitivity (∼3.5 × 105), which is defined as (Iphoto − Idark)/Idark, to above-band-gap irradiation. Under 1000 Hz light switching frequency, the response and recovery times of such photodetector are typically 82 and 179 μs, respectively, and the photoconductive gain is 28, greater than unity. The high photosensitivity and gain, as well as fast response speed, guarantee the feasibility of such self-powered photodetectors.