Self-powered visible-blind ultraviolet photodetectors based on SnO2 nanowire cotton synthesized using thermal chemical vapor deposition

We report a simple method for fabricating a SnO2 nanowire (NW) cotton-based ultraviolet (UV) photodetector. SnO2 NW cotton was synthesized by thermal chemical vapor deposition with SnO powder. Ag paste was coated onto the surface of the SnO2 NW cotton to serve as the electrode. The performance of the photodetector was evaluated upon UV light exposure at a wavelength of 254 nm, with a photo-to-dark-current ratio of 7.9 x 10(5), photoresponsivity of 1.141 x 10(3) A/W, and specific detectivity of 9.0 x 10(15) Jones. The spectral photoresponsivity was also determined in the 200-600 nm wavelength range. The results showed a maximum responsivity at 270 nm and a cutoff edge wavelength of 360 nm, exhibiting the characteristics of a visible-blind UV photodetector. In addition, self-powered capability with a photocurrent of 2.3 nA was demonstrated at a nominal zero bias.