GasFET for the detection of reducing gases

Measurements with a Kelvin probe for testing the sensitive properties of the films and with complete assembled GasFET were performed. The SnO2 thick films activated with Pd show a high sensitivity to CO, hence concentrations lower than 1 vpm can be detected. The sensor response decreases with increasing temperature. A high cross sensitivity to oxygen and humidity is found only for very low oxygen concentrations (∼0 vol.%) or low humidity (∼0% r.h.). Thick films of SnO2 show a similar behavior to changes in the gas atmosphere in measurements performed using the Kelvin probe and with completely assembled GasFET sensors.