Numerical analysis of the effect of the cooling process on the characteristics of n-type semiconductor gas sensors.

Oxygen vacancies play an essential role in the sensing mechanism of semiconductor gas sensors, determining their performance characteristics. To investigate the behavior of oxygen vacancies during a cooling process, a diffusion equation was established based on a model of gradient-distributed oxygen vacancies. Numerical solutions of the diffusion equation were obtained by using a numerical analysis method. The results showed that the oxygen vacancy distribution profile as well as the sensor resistance and response to reducing gas depend on the temperature interval defined by the initial and final temperature of the cooling process. The properties of the sensor can thus be controlled by adjusting the cooling temperature during the fabrication process. [ABSTRACT FROM AUTHOR]