Temperature Effect of the Semiconducting Gas Sensor

Abstract

Nonstoichiometric, n-type semiconducting SnO₂ is commercially applied to a gas sensor material utilizing the phenomenon that its electrical conductivity is affected by the kind and concentration of inflammable gas in air. The gas sensing mechanism has been studied from the viewpoint of chemisorption and electrical conduction, while improvement of the sensor stability has also been attempted. In the present study, the method for gas sensing by measuring the sensor temperature was investigated based on the fact that the temperature of a SnO₂ sensor changes appreciably when in contact with reducing gases. The steady state equation of heat balance made it possible to evaluate the temperature deviation of a sensor, and satisfactory explanation was given to an abnormal self-heating phenomenon which led to an abrupt increase in sensor temperature. Possibility of designing and fabricating a temperature-compensation type gas sensor was proposed.