ZnO oxygen sensor production and characterization with sol-gel spin coating technique

With the development of technology and industry, the importance of human health, efficient use of energy and the impact of harmful gases on the environment has increased the necessity for various sensors. Oxygen sensors are one of them. In recent years, the development of oxygen sensors and whether economical materials that are abundant in nature can be used as oxygen sensors have attracted the attention of scientists. Zinc oxide has become a highly preferred material in the field of technology and scientific studies due to its economical, abundant presence in nature, non-toxicity, and wide width of forbidden energy band. In this study, ZnO thin film was grown on ITO substrate using sol-gel spin coating technique. The characterization of the enlarged thin film was investigated by XRD and electrical measurements. From the XRD measurements, it was observed that the zinc oxide film formed peaks at 30,87°, 35,45°, 50.98° and 60.90° angles (2θ), respectively. It has been observed that these characteristic peaks correspond to [100], [002], [102] and [110] planes, respectively, and when the diffraction pattern is examined, it is in the hexagonal wurtzite crystal structure. The average crystal grain size was calculated to be 3 nm. It has been observed that with the application of oxygen on the thin film, the current increases, that is, the resistance decreases at the same temperature and voltage. It has been determined that this resistance change in the oxygen environment at 400°C is approximately 2 times higher than the air environment.