Gas-sensing system based on the cyclic temperature Further characterization by the second harmonic perturbation

A novel gas-sensing system based on a dynamic nonlinear response is reported to improve the selectivity toward sample gases in the sensor response. A periodic temperature perturbation, which was composed of fundamental and second harmonic temperature changes, was applied to a semiconductor gas sensor and the resulting conductance of the sensor was analyzed by fast Fourier transformation. The dynamic nonlinear response, which changed characteristically depending on the gas species, was enhanced with the application of the second harmonic temperature change. The sensor response under the application of temperature perturbation was theoretically simulated by considering the kinetics of gas molecules on the semiconductor surface.