Improved UV photoresponse of ZnO nanorod arrays by resonant coupling with surface plasmons of Al nanoparticles

In this study, localized surface plasmon resonance mediated by aluminium nanoparticles (Al NPs) was employed to enhance the ultraviolet (UV) response of ZnO nanorod array (NRA) photodetectors grown vertically on a Quartz substrate using a simple vapor transport method. The responsivity of the ZnO NRA photodetector decorated with Al NPs was enhanced from 0.12 to 1.59 A W-1 and the sensitivity and response rate have been improved greatly compared with those of the bare one. The measurement results in the transmittance spectra and time-resolved photoluminescence spectra suggest that the improved photoresponse and the enhanced spontaneous emission of the ZnO NRA photodetector with Al NP decoration are both attributed to resonant coupling between the excitons in ZnO and the localized surface plasmons (LSPs) in the Al NPs. Our results demonstrated that the plasmon-enhanced ZnO NRA photodetector has a great potential for application in building sensors with a fast response and reset time, high sensitivity, and good signal-to-noise ratio for photoelectric sensing.