Enhancement of H2 sensing properties of NiO-based thin films with a Pt surface modification

In this paper, we present the results concerning the Pt surface modification of nickel oxide thin films deposited by dc reactive magnetron sputtering. Pt very thin overlayers; with a thickness of about 3 and 5 nm have been sputtered on the top of NiO samples. The surface structure and morphology of the samples have been analysed by X-ray diffractometer (XRD) and by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. The electrical responses of the NiO-based sensors towards different H-2 concentration (500-5000 ppm) have been also considered. The Pt-modified NiO samples showed an enhancement of the response towards H-2 as compared to the unmodified NiO sample. The thickness of the Pt thin layers seems also an important parameter in determining the properties of the NiO films as H-2 sensors. (C) 2004 Elsevier B.V. All rights reserved.