Can a thin film to be pinned at the surface by hollows?

Glass slices with a low roughness (similar to0.2 nm) irradiated with swift heavy ions were studied by atomic force microscopy (AFM). Ion impacts are materialized by the formation of hollow structures having a maximal depth of similar to3 nm. In order to investigate the role played by such modifications on the surface properties, thin gold films of similar to2 run thickness were deposited on both virgin and pre-irradiated samples. After annealing at 150 degreesC, a red shift is observed in the optical absorption of virgin samples indicating a gold cluster formation, whereas no significant modifications were observed in samples pre-irradiated with energetic Kr ions. By combining AFM observations with optical absorption spectroscopy we discuss in this paper the role played by topographic modifications on both the surface diffusion and the film wetting phenomena. (C) 2002 Published by Elsevier Science B.V.