Optimization of sol–gel based ZnO metal–semiconductor–metal UV detectors by Zr doping through sputtering method

Abstract

In this study, to improve the properties of ZnO-based metal–semiconductor–metal (MSM) UV detectors, the surface of ZnO thin films prepared by the sol–gel method is initially doped with Zr sputtering at different time intervals. The amount of Zr at the surface and its effect on the crystalline structure and the surface morphology are, respectively, evaluated through energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) analysis, and atomic force microscopy (AFM). Then, by creating electrodes on the surface, these layers are converted to MSM UV detectors and subjected to various sensor tests to assess their performance. The results of these tests show that the sensors, which are sputtered with Zr for 50 s under the experimental conditions in question, experience an increase in the photoresponsivity by about one order of magnitude while their rise time and recovery time decrease about 30%. Furthermore, the best repeatability of I–t curves and baseline stability in consecutive cycles are also related to these sensors. The experience also indicates that the use of sputtering method can be seriously considered to modify the surface of nanostructures used in the construction of sensors. This makes perfect sense because the surface plays a major role in the detection mechanisms in most light and gas sensors. It is noteworthy that this method can be used even to modify the properties of pre-made detectors.