INFLUENCE OF ROOM TEMPERATURE ON THICK-FILM GAS SENSORS

Nanostructured semiconductor gas sensors are notoriously very sensitive to a huge number of environmental parameters, such as humidity and ambient temperature. It can be noticed that even if we keep the film temperature constant through an electronic feedback, variations of the ambient temperature lead to conductance variations. In this work we try to understand the nature of this dependence. In order to study the correlation between the response and the temperature of the film, of the air near the film and of the ambient temperature a thermal exchange mathematical model has been developed. A simple experimental configuration has been taken into account, with the heated film placed inside the protection cap, the whole sensor inside the test box and the test box subjected to environmental temperature, and the model was solved numerically and compared with the experimental data.