Substrate effects on the electronic structure of metal overlayers—an XPS study of polymer-metal interfaces

Abstract

The electronic structures of copper, nickel, and chromium overlayers on polystyrene and polyvinyl alcohol have been investigated with x-ray photoemission spectroscopy. At submonolayer coverages, the peak position and width of the metallic-core levels vary significantly from one substrate to the other. Most of these variations can be accounted for in terms of changes in the atomic and extra-atomic relaxation energies during the photoemission process. Much of this change is brought about when the metal atom deposited on polyvinyl alcohol interacts with the substrate oxygen and forms a metal-oxygen-polymer complex. The presence of this complex is verified by changes in the photoemission line shapes of the substrate carbon and oxygen atoms.