Sol–gel grown Pd modified WO3 thin film based methanol sensor and the effect of annealing temperatures

In this paper, Pd modified WO 3 thin film methanol sensor has been developed by sol–gel method. WCl 6 chemical compound is used as a precursor. Spin coating method is employed for the preparation of the WO 3 thin film on the Si substrate. The crystalline structure of the WO 3 thin film is analyzed by scanning electron microscopy and X-ray diffraction techniques. The thin film sensor is fabricated at different annealing temperatures (400, 600 and 800 °C). The response magnitude of the WO 3 thin film is studied at different operating temperatures (100–300 °C). It is observed that the operating temperature of Pd modified thin film sensor is 200 °C. It is also noticed that the maximum response magnitude of Pd modified WO 3 thin film sensor is found at the annealing temperature of 600 °C. It is found that Pd modified WO 3 thin film sensor are suitable for methanol vapour detection compare to unmodified WO 3 thin film senor.