Sol-gel spin coating derived ZnO thin film to sense the acetic acid vapor

ZnO thin film of 80 nm thickness was deposited by the sol-gel spin coating method on SiO2/Si substrate and subsequently post-annealed at 500°C with a flow of oxygen for 60 min. Crystallographic structure of the sample was characterized by X-ray diffraction (XRD) method while a field emission scanning electron microscope (FESEM) was used to investigate the surface physical morphology and chemical composition. The sensitivity of the sample was tested to acetic acid vapor with different concentrations (20 ppm, 40 ppm, and 80 ppm) in the temperature range of 200-400 °C. The results showed that the ZnO thin film can be introduced as an acetic acid vapor sensor with a good reliability and detection limit of 20 ppm at the operating temperature of 320°C.