High-performance photodetectors for visible and near-infrared lights based on individual WS2 nanotubes

We propose that a photodetector based on nanotubes formed from layered structure may have a faster response than nanowires or nanobelts. The layered compound tungsten disulfide (WS2) can absorb visible and near-infrared lights. We fabricated photodetectors based on individual WS2 nanotubes. The photodetectors exhibited a remarkable response to excitation with 633 and 785 nm light. The nanotube-based photodetectors exhibited short rise and decay times of a few hundred mu s, high on/off ratio, and high spectral responsivity and external quantum efficiency. Our results imply that WS2 nanotubes are prospective candidates for high-performance nanoscale optoelectronic devices. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4729144]