High-performance UV-Vis-NIR photodetectors based on plasmonic effect in Au nanoparticles/ZnO nanofibers

In this study, UV-Vis-NIR photodetectors based on decorated ZnO nanofibers (NFs) with optimized coverage of Au nanoparticles (NPs) fabricated via combined simple electrospinning and sputtering techniques are introduced. The effect of different coverages of Au NPs resulted from different Au nominal layer thicknesses on the morphology and optical properties of the ZnO fibers are investigated through various characterization methods. It is discovered that 4 nm Au nominal thickness provides the highest UV on/off ratio (similar to 460), responsivity (similar to 332 A/W), detectivity (similar to 2.93 x 10(11) Jones) as well as faster rise and decay times as compared to pure ZnO nanofibers. A broad spectral response from UV to NIR with high photoresponsivity and fast response time (< 0.5 s) in the visible and NIR regions are achieved for the sample decorated with 8 nm Au nominal thickness. Response to visible and IR irradiations and initial fast response to UV are originated from localized surface plasmon resonance (LSPR) absorption of the Au NPs and effective separation and transport of photogenerated carriers, wherein slow response to UV is due to adsorption/desorption of oxygen species.