Gas sensing properties of WO3 thick film for NO2 gas dependent on process condition

Abstract

The thick film sensor of tungsten-oxide for NO2 gas detection was fabricated by changing the process conditions, which were firing temperature and annealing atmosphere. The origin of sensor property variation was interpreted by the characterization of crystallite size, specific surface area and microstructure. The degree of oxygen deficiency in the WO3 sensor also affected sensor properties and the optimum oxygen content of WO3 was necessary to get high sensitivity for NO2. The WO3 thick film fired at 700 °C and operated at 100 °C showed excellent sensor properties, and its operation temperature is lower than that from other reports.