Abstract
The electrical and gas sensing properties of the sprayed Cu doped ZnO thin layers were investigated. The main study is an analysis of the conduction mechanism based on the measurement results of the frequency dispersion of the conductivity at different temperatures performed by impedance spectroscopy. It emerges from this study that the transport mechanism of charge carriers in such thin films is a thermally activated hopping mechanism. This process is confirmed by the obtained values of the maximum barrier height Wm deduced from the study of the frequency power law of the ac conductivity. Otherwise, we have studied the response evolution of ZnO: Cu sensors ethanol versus time, working temperature and relative doping. From the measurement results of gas sensing properties of ZnO:Cu thin film, we find that a good stability and response was observed for a doping of 2%.
•This work contains theoretical and experimental aspects of electrical and gas sensing properties.•The ac conductivity of the sprayed ZnO:Cu thin layers obeys the frequency power law.•The transport mechanism of charge carriers in these layers is a thermally activated hopping mechanism.•The positive effect of doping the copper ZnO layer at a rate of 2%.•ZnO:Cu 2% is an appropriate candidate for an ethanol vapor sensor.