Effect of temperature modulation, on the gas sensing characteristics of ZnO nanostructures, for gases O2, CO and CO2

Abstract

One dimensional nanostructures of ZnO grown by microwave assisted wet-chemical growth were drop casted over inter-digitated electrodes to fabricate chemi-resistive sensors. The response of this intrinsic, intentionally undoped ZnO nanomaterial, to gases O2, CO and CO2 was measured as a function of sensor operating temperature and analyte gas concentration. The sensor resistance increases upon exposure to O2 and decreases on exposure to CO and CO2. Temperature dependence data for the three gases show the maximum sensor resistance occurring in the temperature range 300 °C to 350 °C. An analysis of the sensor resistance data in temperature range 250 °C to 350 °C demonstrate that, the modulation of sensor operating temperature alone is sufficient to tailor gas sensing response of the ZnO nanomaterial. These data are important and necessary for operating the sensor in the form of an array with an appropriate pattern recognition tool.