Synthesis and gas sensing behavior of nanostructured V2O5 thin films prepared by spray pyrolysis

Nanocrystalline vanadium pentoxide (V2O5) thin films have been deposited by a spray pyrolysis technique on preheated glass substrates. The substrate temperature was changed between 300 and 500 °C. The structural and morphological properties of the films were investigated by means of X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and atomic force microscopy (AFM). The influence of different substrate temperatures on ethanol response of V2O5 has also been investigated. XRD revealed that the films deposited at Tpyr=300 °C have low peak intensities, but the degree of crystallinity improved when the temperature was increased to 500 °C and films had orthorhombic structures with preferential orientations along the (0 0 1) direction. The fractal analysis showed a decreasing trend versus the pyrolysis temperature. Sensing properties of the samples were studied in the presence of ethanol vapor. The operating temperature of the sensor was optimized for the best gas response. The response increased linearly with different ethanol concentrations. It was found that films deposited at the lowest substrate temperature (300 °C) had the highest sensing response to ethanol.