Study on influence of Fe doping into ZnO film for ethanol sensing

Abstract

In recent times, the importance of nanostructure of metal oxide semiconductor (MOS) as a gas sensing material is rising tremendously. Among various metal oxide semiconductors ZnO has potential to be used as a sensor for several toxic gases. In this work, we investigated the influence of Fe doping into ZnO to detect various concentrations of ethanol vapour. Pristine and Fe doped ZnO (Fe-ZnO) films were deposited on glass substrates using a spin coating technique wherein the concentration of Fe can be easily controlled. The crystallite size and surface morphology of ZnO samples were characterized by XRD, SEM and EDX techniques. The sensor performance in terms of gas response (R) of ZnO and Fe-ZnO gas sensors towards ethanol vapour were measured in the 100 to 300 C temperature range using DC electrical resistance. Fe doped ZnO samples showed enhancement in gas response due to increase in specific surface area originated from reducing grain size after doping. The 2% Fe-ZnO sample showed the good response of 40.9 for 400 ppm of ethanol vapour exposure at 260 C. This was found to be better than reported values for ZnO prepared by different methods.