Deposition Rate Influence in O3 Sensing Response of Sputtered ZnO Thin Films

The study of semiconductor materials applied as chemical gas sensing devices is currently focused on the production of new sensing materials with the best possible properties in terms of detection limits, selectivity, work temperature and response time. Although theoretical models show the great importance of film morphology on gas detection, a direct relation between structure size/morphology and the gas sensing properties has not been experimentally established. In this work, RF-sputtering deposition technique was used for the synthesis of zinc oxide thin films, and deposition conditions are variated to achieve a remarkable difference in nanostructure size of the material. The electrical resistance variation of the air-exposed films in presence of different ozone concentrations show a strong dependence on the feature size and film morphology, demonstrating the effectiveness of use the parameters of RF sputtering deposition as tunable factors to improve the ZnO sensing properties