The interfaces formed by evaporating copper, nickel, and chromium layers on polystyrene, polyvinyl alcohol, polyethylene oxide, polyvinyl methyl ether, polyvinyl acetate, and poly~ethyl methacrylate have been studied with x-ray photoemission spectroscopy (XPS). The adhesIOn strengths of the metal films to the polymers were measured by a tensile-pull test. At submonolayer coverages of the metals, the peak positions and widths of the metallic electron core levels measured with XPS vary significantly from one polymer substrate to another. 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 an oxygen-containing polymer interacts with the substrate oxygen and forms a metal-oxygen-polymer complex. The presence of this complex is verified by changes in the photoemission lineshapes of the substrate carbon and oxygen atoms. The XPS signatures ofthese various complexes are quite similar and suggest that they are chelate-like complexes. The adhesion strength of any metal on an oxygen-containing polymer is greater than on the oxygenfree polystyrene. In general, the increased adhesion strength correlates with the presence of the metal-oxygen chelate complexes. PACS numbers: 82.80.Pv, 81.60.Jw, 68.90. + g 4795

Adsorbed layers of nitrogen and oxygen in the c(2 X 2) structure and sulfur in the (2 X 2) structure on copper (100) have been studied. Ultraviolet photoemission spectroscopy (UPS) shows that each of these layers induces a resonance above the "d band" of copper at about 1.3-eV binding energy with respect to the Fermi level and below the "1 band" at about 6-eV binding energy. X-ray photoemission spectroscopy has been used to determine that the 1s electronic binding energies of adsorbed atoms of c(2 X 2) nitrogen and oxygen are 396.3 and 529.8 eV, respectively, and that the 2p electronic binding energy of adsorbed 2 X 2 sulfur is 161. 2 eV. The highest-energy Auger peaks excited by each of these core holes may be interpreted as arising from Auger transitions involving the surface electronic states measured in these UPS experiments. Good agreement with most features of the experimental Auger spectra has been obtained using measured and calculated data for the surface electronic binding energies under the assumption that Auger final-state effects are small. Therefore the evidence points to the formation of a copper-adsorbate surface complex in which these UPS-observed resonances have a high local density of states at the adsorbate atom cores and in which the final-state hole momenta are only loosely coupled.

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The reaction of a clean Cu(100) surface with atomic N has been studied with low energy electron diffraction (LEED), Auger electron spectroscopy, ultraviolet photoemission spectroscopy (UPS), and x-ray photoemission spectroscopy (XPS). Atomic nitrogen, formed by electron dissociation of N2 forms a c(2×2) overlayer on the Cu(100) surface. An analysis of LEED intensity profiles averaged over constant momentum transfer indicates that the N binds in a fourfold symmetric site, 0.145 nm above the first layer of Cu atoms. UPS data reveal small adsorbate-induced electronic levels at 1.3 and 5.8 eV below the Fermi level, in addition to rather complex changes in the Cu d band. XPS measurements yield 397.3 eV for the binding energy of the N 1s electrons with respect to the Fermi level. Our UPS and Auger data on Cu(100)/N in terms of N-induced states is shown to be plausible.