Ultraviolet sensor with fast response characteristics based on an AgNW/ZnO bi-layer

Abstract

We demonstrate an ultraviolet (UV) sensor with fast response characteristics based on an AgNW/ZnO bi-layer. This UV sensor is a surface acoustic wave (SAW)-based sensor fabricated using a 128 degrees YX black lithium niobate substrate, which is a piezoelectric in nature. This sensor, which is a two-port SAW resonator, was manufactured by fabricating interdigitated electrodes with a wavelength of 16.4 mu m and depositing UV sensing layers such as ZnO, Sn/ZnO, and AgNWIZnO. Among these sensing layers, the frequency response characteristics were found to be improved in the bi-layer structure. In addition, the AgNWIZnO-based sensor showed a significant improvement in response and recovery times. These results contributed to rapid oxygen adsorption on the ZnO surface due to the large oxygen contact area that can attributed to the AgNW's 3D mesh structure and the compensation of the internal electron trap center due to the contact of the metal-semiconductor. The proposed sensor with the metal-semiconductor bi-layer structure based on AgNW nanomaterials showed the fastest response characteristics compared to previous SAW UV sensors. (C) 2020 Elsevier B.V. All rights reserved.