A novel method in the gas identification by using WO_3 gas sensor based on the temperature-programmed technique

摘要

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 WO_3 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 WO_3, 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{[InσT~(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.