The Sensing Mechanism in a Semiconducting Humidity Sensor with Pt Electrodes

The sensitivity of semiconducting humidity sensors increased with a rise in firing temperature when Pt electrodes were used; such enhancement of sensitivity was not observed for sensors with electrodes. From these results, a sensitization model based on variations in the amount of oxygen adsorbed on the Pt particles, which were deposited on the surface of grain boundaries in the interior part of the by thermal diffusion, with the firing temperatures of the Pt electrodes has been presented. The validity of this model was confirmed by the fact that enhancement of the sensitivity was achieved even at a low firing temperature of the electrodes by depositing Pt on the specimen prior to the firing.