XPS and atomic force microscopy analyses of thin Au and Cu films on Pd

The surface properties of bimetallic systems have been studied recently due to possible applications in different areas, such as electrochemistry, magnetism, and catalysis. Understanding of the atomic and electronic structures is crucial for designing metallic devices. In this work, thin films of gold and copper were grown on a polycrystalline palladium substrate by sputtering. For both films, the thickness was estimated to be 10 nm. The morphology of the films was investigated by atomic force microscopy (AFM). XPS was employed in order to verify the possibility of alloy formation. Oxide formation was observed for the Cu film, but not for the Au film. The copper oxide (CuO) was removed by argon ion sputtering. Alloying was not observed in the Au/Pd or Cu/Pd films. Copyright © 2004 John Wiley & Sons, Ltd.