Selectivity and sensitivity studies on plasma treated thick film tin oxide gas sensors

This paper deals with selectivity and sensitivity studies on plasma treated tin oxide thick film gas sensors. Response of oxygen, hydrogen, nitrogen and argon plasma treated sensors has been studied upon exposure to CCl4, C3H7OH, CO, LPG, N2O and CH4. It is observed that the sensitivity of sensors treated in various gaseous plasma is much higher at room temperature in comparison to untreated sensors. The selectivity of these sensors also improves upon plasma treatment, specifically, hydrogen plasma treated sensor becomes sensitive to CO. Also, the XRD characterization of SnO2 has been carried out with respect to various plasma treatments. The structural changes obtained on plasma treatment have been analysed in terms of stoichiometric variations in tin oxide using the ionic conduction model and a thus better explanation for sensitivity of plasma treated sensors have been provided. (C) 2000 Elsevier Science Ltd. All rights reserved.