Hierarchical CdS Nanowires Based Rigid and Flexible Photodetectors with Ultrahigh Sensitivity

Hierarchical CdS nanowires were synthesized via a facile vapor transport method, which were used to fabricate both rigid and flexible visible-light photodetectors. Studies found that the rigid photodetectors on SiO2/Si substrate showed ultrahigh photo-dark current ratio up to 1.96 x 10(4), several orders of magnitude higher than previously reported CdS nanostructures, as well as high specific detectivity (4.27 x 10(12) Jones), fast response speed and excellent environmental stability. Highly flexible photo detectors were also fabricated on polyimide substrate, which exhibited comparable photoresponse performance as the rigid one. In addition, the as-prepared flexible devices displayed excellent mechanical flexibility, electrical stability and folding endurance. The results indicate that the hierarchical CdS nanowires may be good candidates for nanoscale optoelectronic devices such as high-efficiency photoswitches and highly photosensitive detectors.