Influence of surface properties on the metal oxide sensor response to a steep change in air composition

The resistance response to a steep change in composition of the atmosphere was studied in metal oxide thin film gas sensors. Deposition temperature and the doping with impurity metals were intentionally varied for the sensor parameters could be modified. Chemical composition and the morphology of the modified sensors were determined by XPS and SEM. Time dependence of the resistance change was measured in the sensors included in an array after the steep change in the composition of the atmosphere. An influence of the surface properties on the sensitivity was interpreted by a phenomenological model in which a relationship between the response kinetics and the rates of the surface catalytic reaction was defined. Based on the response kinetics of the sensor array, features of the target smell was visualised by an original method in the two-dimensional multilayer plot. The smell of bacteria infected meat was recognised by this method.