Thermally induced reaction and diffusion of carbon films on Ni(111) and Ni(100)

Thin carbon films on Ni(111) and Ni(100) and the reactive and diffusive interactions between film and substrate are investigated using X-ray photoelectron spectroscopy (XPS). The carbon films are deposited from the vapor phase with the substrates at room temperature. After deposition the films contain mainly elemental carbon. Restricted only to the carbon-nickel interface carbidic carbon is observed. Carbon films of various thicknesses between 0.4 and 3.2 nm are investigated after thermal treatments up to 970 K. The C 1s signal intensities are used for chemical analysis, both in a qualitative and quantitative way. The initially formed carbide partially decomposes between 400 and 570 K. Additional carbide formation sets in again, combined with incipient carbon diffusion, at higher temperatures. Carbon diffusion into the bulk leads to a decreasing C 1s signal intensity until the carbon is almost completely lost into the bulk.