Highly Sensitive Broadband Single-Walled Carbon Nanotube Photodetectors Enhanced by Separated Graphene Nanosheets

摘要

Single-walled carbon nanotube (SWCNT)/graphene Schottky junctions have great potential for high-performance all-carbon photodetector due to their excellent optical and electronic properties and efficient charge transfer. However, the further improvement of device performance is limited by the low absorption of ultrathin SWCNTs and large dark current of continuous graphene nanosheets. Here a proof-of-concept photodetector is reported using SWCNT/separated graphene (SGR) hybrid networks. The device is sensitive to a broadband wavelength from visible light to near-infrared light (405–1064 nm), showing an extremely high photoresponsivity of >3000 A W~(−1), a fast response speed of 44 μs, and high photoconductive gain of ≈4 × 10~6. Furthermore, the results demonstrate first the charge transfer dynamics at the planar SWCNT/SGR Schottky junctions by combining Raman spectra with current–voltage curves. The architecture strategy opens a new general route to fabricate ultrahigh-performance photodetectors based on SWCNT/SGR hybrids or other semiconductor/graphene hybrids.