Nanocrystalline V2O5–TiO2 thin-films for oxygen sensing prepared by sol–gel process

The binary nanosized V2O5–TiO2 thin-film sensors were made by use sol–gel technique. The properties of these films were investigated by the X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). As characterised by SEM and XRD, the films after annealing at 500°C, were about 0.8 mm thick and consisted of a monoclinic polycrystalline structure with an average grain size in the range of 3–5 nm. The properties of the sensors based on V2O5–TiO2 thin-film have been investigated in the temperature range of 200–350°C. These sensors are capable to detect oxygen from 10 ppm up to 20.9% at an operating temperature range of 200–350°C. The response time was about few minutes. It was also found that these sensors relatively insensitive to ozone.