ZnO nanoparticles or ZnO films: A comparison of the gas sensing capabilities

Zinc oxide is an interesting material for bio and chemical sensors. It is a semiconducting metal oxide with potential as an integrated multisensing sensor platform, which simultaneously detects parameters like change in field effect, mass and surface resistivity. In this investigation we have used resistive sensor measurements regarding the oxygen gas sensitivity in order to characterize sensing layers based on electrochemically produced ZnO nanoparticles and PE–MOCVD grown ZnO films. Proper annealing procedures were developed in order to get stable sensing properties and the oxygen sensitivity towards operation temperature was investigated. The ZnO nanoparticles showed a considerably increased response to oxygen as compared to the films. Preliminary investigations were also performed regarding the selectivity to other gases present in car exhausts or flue gases.