A novel method in the gas identification by using WO3 gas sensor based on the temperature-programmed technique

Selectivity has been considered as one of the most significant performances to evaluate the practical application of the metal oxide semiconductor (MOS) gas sensor. Temperature modulation is now a commonly recognized method in enhancing the sensor selectivity as it can reflect more feature reaction information. In this paper, a novel method in the gas identification by using WO3 gas sensor based on the temperature-programmed modulation is reported. This method allows us to be capable of dynamically obtaining the temperature-dependent electrical conductivity (TEC) spectra in different atmospheres. In terms of the TEC of the WO3, a rigorous method for extracting the feature parameters is presented here, which are associated with the gas adsorption/desorption and defect reaction mechanisms, from the differential curve d{[ln sigma-T-3/2]}/dT-T. According to the feature parameters, we can clearly figure out the gas species that cannot be accomplished by the conventional methods. The temperature-programmed modulation thus provides a fundamental method for accurately identifying the gas species and is expected aid in opening up a new way to investigate the selectivity of the MOS gas sensors. (C) 2014 Elsevier B.V. All rights reserved.