UV-vis-IR Broad Spectral Photodetectors Based on VO 2 -ZnO Nanocrystal Films.

As a narrow band semiconductor at room temperature and a metallic material above ∼68 °C, functional VO 2 films are widely investigated for smart windows, whereas their potential for ultraviolet-visible-infrared (UV-vis-IR) broad spectral photodetectors has not been efficiently studied. In this report, photodetectors based on VO 2 -ZnO nanocrystal composite films were prepared by nanocrystal-mist (NC-mist) deposition. An enhanced photodetection switching ratio was achieved covering the ultraviolet to infrared wavelength. Due to the synergetic effect of nanosize, surface, phase transition, percolation threshold, and the band structure of the heterojunction, the transfer and transport of photogenerated carriers modulate the device performance. This study probes new chances of applying VO 2 -semiconductor-based nanocomposites for broad spectral photodetectors.