Ultraviolet photosensors fabricated with Ag nanowires coated with ZnO nanoparticles

We have developed a simple low temperature process to coat zinc oxide (ZnO) nanoparticles (NPs) on Ag nanowires (NWs) with well-controlled morphology. Triethanolamine (TEA) was employed to react with zinc acetate (Zn(CH3COO)2) forming ZnO NPs. TEA was also found to enhance the nucleation and binding of ZnO NPs on the Ag nanowire surfaces facilitating a complete coverage of Ag nanowire surfaces with ZnO NPs. The effects of the process parameters including reaction time and reaction temperature were studied. The surfaces of 60 nm diameter Ag NWs could be completely covered with ZnO NPs with the final diameters of Ag-NWs@ZnO (core-shell NWs) turning into the range from 100 nm to 450 nm. The Ag-NWs@ZnO was characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray mapping analysis, X-ray diffraction, and photoluminescence spectra. Finally, ultraviolet (UV) photosensors were fabricated using Ag-NWs@ZnO. They were found to improve photosensitivity with greatly enhanced fast response by reducing the recovery time by 2 orders, in comparison with the UV-sensors using single-crystalline ZnO NWs.