Sensitivity and selectivity enhancement in WO3 and Cr2-xTixO3 thin films deposited by pulsed laser ablation

In this work materials and thin film preparation procedures suitable for gas sensing applications have been investigated with the aim to preserve sensitivity, enhance selectivity and to reduce drift. Thin films sensing layers based on WO3 and CrTiO3 deposited by pulsed laser ablation (PLA) techniques were fabricated and comparatively characterized. Three issues were mainly addressed: the variation of the conductivity as a function of RH, the sensitivity to C6H6, CO, C2H6CO and NO2 as tracing gases for air quality, and the selectivity. Data obtained from mid-term measurements performed on the sensors will be discussed in comparison with the results of structural analyses performed by X-ray and TEM investigations and with chemical composition analyses carried out by XPS.