Ag nanorods assembled with ZnO nanowalls for near-linear high-response UV photodetectors

Abstract We developed a simple method of sonication combined with annealing treatment method to construct ZnO/Ag heterostructures from Ag nanorods assembled in-situ with ZnO nanowalls, which were then characterized by FESEM, EDS, XRD, XPS, PL, UV-vis spectra. A perfect heterojunction was formed by Ag nanorods inserted into the holes of 3D ZnO nanowalls. Compared with pure ZnO nanowalls, the ZnO/Ag heterostructures have more vacancy defects and a red shift in absorption. The effects of the working temperature on sensors fabricated with ZnO/Ag heterojunction were investigated. The photodetector demonstrated higher photo response activity as well as a faster response speed and excellent environmental stability compared to pristine ZnO nanowalls, and the photoresponse exhibited a better linear relationship at 10 °C ∼70 °C. The mechanism of UV photo sensing for the ZnO/Ag heterojunction was discussed. The results indicated that ZnO/Ag heterojunction could act as an interesting material for UV photodetectors with near-linear responses in outdoor temperatures.