Detection of CO and NO using low power metal oxide sensors

Abstract

Abstract In this work we present the fabrication and characterization of low power SnO 2 gas sensors based on Porous Silicon micro‐hotplates for the detection of toxic gases, like CO and NO. The response of the SnO 2 gas sensors was measured for various gas concentrations (100‐500 ppm). Analysis was performed in isothermal operation mode, by keeping constant the micro‐hotplate temperature and in pulsed temperature mode, by applying voltage pulses to the heater. In both cases, the response of the sensors increased as the temperature and the concentration of the detecting gases increased. Comparison between the two different operation modes, shows that the sensors exhibit higher sensitivity in pulsed temperature mode. In addition, with this technique, a significant reduction of power consumption can be achieved. Moreover, the sensors show significant selectivity in detecting NO, so discrimination between the two gases can be achieved. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)