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

The thick film sensor of tungsten oxide for NO2 gas detection was fabricate d by changing the process conditions, which were firing temperature and ann ealing atmosphere. The origin of sensor property variation was interpreted by the characterization of crystallite size, specific surface area and micr ostructure. The degree of oxygen deficiency in the WO3 sensor also affected sensor properties and the optimum oxygen content of WO3 was necessary to g et high sensitivity for NO2. The WO3 thick film fired at 700 degrees C and operated at 100 degrees C showed excellent sensor properties, and its opera tion temperature is lower than that from other reports. (C) 1999 Elsevier S cience S.A. All rights reserved.