Gas sensing properties of tungston oxide thin films in Methane and Nitric oxide gases
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Date
2009
Authors
Samarasekara, P.
Journal Title
Journal ISSN
Volume Title
Publisher
University of Peradeniya,
Abstract
Tungsten oxide (WO3 ) thin films, which were synthesized between micro-patterned gold electrodes and annealed at 500 o C in air for 2 hours, were developed as methane (CH4 ) and nitric oxide (NO) gas sensors. The as-deposited films exhibited an amorphous structure and annealed films indicated crystalline WO3 with the average grain size of 40 nm. The structure of films was determined by means of X-ray diffraction (XRD) methods. The highest sensitivity for 10 ppm NO gas in air at 255 o C was 0.9 and 1.6 for thin and thick WO3 films, respectively. The respond and recovery times of thinner films were faster than thicker films. The sensitivity was also measured for high concentration level of methane gas for comparison. The highest methane gas sensitivity was 6.5 for 6% methane in air at 355 o C. The origin of this gas sensitivity can be explained using grain boundary control model
Description
Keywords
Gas sensing properties , Tingston oxide , Thin films , Methane , Nitric oxide
Citation
Georgian Electronic scientific Journal: Physics Vol. 2, No. 2, 2009 pp. 44-50