Performance enhancement of ZnO ultraviolet detector by localized surface plasmon resonance of Al nanoparticles

Ultraviolet (UV) photodetectors have attracted much attention due to their important applications in many fields. Improving of the photoelectric performance of ultraviolet detectors is the key challenge. One solution is to fabricate UV photodetectors based on a wide bandgap semiconductor material—zinc oxide (ZnO). Here, ZnO nanorods with pure surface and high crystallization are prepared by laser ablation in liquid combined with hydrothermal method. The bandgap of ZnO products calculated from UV–vis reflection spectra is 3.43 eV, which means the ZnO nanorods synthesized in this work are suitable for UV detection. Moreover, Al nanoparticles with localized surface plasmon resonance (LSPR) are also prepared by laser ablation in liquid. The UV photodetector based on the ZnO nanorods and Al nanoparticles is fabricated. It is found that the photoelectric performance of ZnO-based UV photodetector is significantly increased after the addition of Al nanoparticles. The mechanism is that the LSPR happens when laser irradiated on the ZnO nanorods with Al nanoparticles, so the absorption is enhanced. Therefore, the ZnO nanorods get more light energy, which means more photo-induced carriers are generated and the current will increase.