A NONLINEAR DIFFUSION-REACTION MODEL OF ELECTRICAL-CONDUCTION IN SEMICONDUCTOR GAS SENSORS

A non-linear diffusion-reaction model of electrical conduction in homogeneous semiconductor gas sensors has been developed. It is shown that the transient response time of a device may be classified according to the relative importance of diffusion and reaction rates. Experimental results on tin oxide thick films show that the response time is predominantly diffusion limited, suggesting that an improvement in performance may be achieved through a modification in physical properties, such as film porosity, instead of the underlying chemical kinetics. © 1990.