Sensing characteristics of nio thin films as NO2 gas sensors

In this paper we present the results concerning the characterisation of nickel oxide thin films deposited by d.c. reactive magnetron sputtering. Different NiO thin films have been prepared by changing some deposition parameters, as the oxygen content in the reactive plasma and the sputtering mode (metal- or oxide-sputtering mode). The structure and surface morphology of the samples have been analysed by XRD and by atomic force microscopy and scanning electron microscope, respectively. The electrical responses of the NiO films towards NO2 have been also considered. NiO thin films showed good responses to low NO2 concentrations (1–10 ppm) with a maximum at 160 °C operating temperature.