CHARACTERIZATION OF HAFNIUM OXIDE-FILMS MODIFIED BY PT DOPING

The Hf/HfO2-Pt electrodes were prepared through galvanostatic platinum deposition from H2PtCl6 solutions followed by potentiodynamic HfO2 growth in 0.5 M H2SO4 solutions. Electron transfer reactions involving a redox couple and impedance investigations were performed in order to obtain information about the electronic conductivity, dielectric properties and thickness of the oxide film as well as the kinetics of the processes taking place on it. X-ray photoelectron spectroscopy (XPS) was used to characterize the composition and dopant distribution profile within the modified film and to correlate the electrochemical behaviour with the structure and composition of the films. A transition from n-type semiconductor tb an insulator behaviour was observed at lower Pt content with increase of the final formation potential which is in agreement with platinum distribution through the oxide. At higher Pt content, on the other hand, the oxygen evolution reaction prevails over oxide growth reaction, These results are discussed in terms of a physical model for the system.