Gas sensing properties of WO3 thin films deposited by rf sputtering

WO3 thin films were deposited by reactive radio frequency (rf) sputtering from a pure tungsten target. The deposition process was conducted with three interruptions and the interruption time was 30, 90 and 300 s. On the basis of these films, sensing layers were prepared and their responses to NO2, ammonia and ethanol were investigated. It was found that the sensing layers prepared with an interruption time of more than 90 s showed the best sensing properties.