A gas-sensing system based on a dynamic nonlinear response is reported to improve the selectivity in the sensor response toward sample gases. A cyclic temperature composed of fundamental and second harmonics was applied to a SnO(2) semiconductor gas sensor and the resulting conductance of the sensor was analyzed by fast Fourier transformation (FFT). The dynamic nonlinear responses to the gas species were further characterized depending on the scanning profile of the temperature. These characteristic sensor responses under the application of second-harmonic perturbation were theoretically considered based on a reaction-diffusion model for the semiconductor surface.

No abstract

No abstract

A novel gas-sensing system based on a dynamic nonlinear response is reported to evaluate the effect of gaseous mixtures on the sensor response. A sinusoidal temperature perturbation was applied to a semiconductor gas sensor and the resulting conductance of the sensor was analyzed by fast Fourier transformation (FFT). The sensor response, which changed characteristically depending on the composition of the gaseous mixture, could be classified into three types (enhanced, suppressed, and preferential responses) by the mixture. To monitor the progress of the reaction of gases, the sample gas was analyzed by gas chromatography. The coexistent effect on the response to gaseous mixtures was theoretically simulated by considering the kinetics of gas molecules on the semiconductor surface.

No abstract