Effect of Annealing Temperature on Gas Sensing Performance of SnO^sub 2^ Thin Films Prepared by Spray Pyrolysis

The effect of variation of annealing temperature on the gas sensing characteristics of SnO^sub 2^ thin films, which have been prepared by spray pyrolysis on alumina substrate at 350 °C, is investigated systematically for various gases at different operating temperature. The XRD, UV-visible spectroscopy and SEM techniques were employed to establish the structural, optical and morphological characteristics of the materials, resp. The X-ray diffraction results showed an increase in the crystallinity at higher annealing temperature. A high value of sensitivity is obtained for H^sub 2^S gas at an optimum temperature of 100 °C is improved considerably. A SnO^sub 2^ gas sensor annealed at 950 °C with sensitivity as high as 24 %, 4 times higher than that of sensor annealed at 550°C, are obtained for 80 ppm of H^sub 2^S. The degree of crystallinity and grain size calculated from the XRD patterns has been found increasing with annealing temp. [PUBLICATION ABSTRACT]