Noise spectroscopy measurements in metallic oxide gas microsensors

Noise spectroscopy is one of the solutions to enhance the selectivity of metal oxide sensors. This experimental technique is based on analysis of the power spectral density of noise fluctuations measured at the terminals of sensors in the presence of one or more gas. A specific noise measurement system has been developed to characterize the low frequency noise behavior of SnO₂ gas microsensors under various gases. The noise voltage spectral density can be interpreted in terms of number fluctuations of the adsorbed molecules called adsorption-desorption noise. Our experimental results confirmed that noise spectroscopy could be used as a mean of improving gas sensors selectivity.