A THEORETICAL-STUDY ON THE GAS SENSITIVE CHARACTERISTICS OF SEMICONDUCTIVE CERAMIC SENSORS

When adsorbed oxygen ions react with introduced reducing gas molecules , the fraction of densities of reacted oxygens and originally adsorbed oxygens was assumed to correspond to the fraction of surface occupied by introduced gas molecules used in the Langmuir equation. According to Boltzmann statistics and Langmuir equation, we obtain an analytic e xpression of sensitivity of sensor as a function of concentration of r educing gas, heating temperature and material parameters. The theoreti cal results are in good agreement with the experimental data which has been reported on ZnO and SnO2 sensor.