Characterization of WO3 thin films prepared by picosecond laser deposition for gas sensing

In this study we report on an investigation of the gas sensing properties of WO3 thin films deposited by ps-pulsed laser deposition. Morphological, electrical and gas sensing properties with respect to CO and NO2 are compared, for different layers with increasing porosity with increasing oxygen pressure during deposition. The base resistance under ambient conditions was investigated and found to be highly dependent on the morphology, controlled by the grain-grain contacts. We found that highly porous films show also high resistive response to NO2 and CO.