Experimental evidence of a diffusion size effect in thin Au films on Ag(111)

The diffusion size effect, determined by near-surface thin film lattice dynamics, has been experimentally discovered. The investigation was carried out by means of Auger electron spectroscopy enabling determination of the atomic accumulation of the Ag substrate on the (111) surface of the epitaxial Au film. The authors have shown that the diffusivity D(x) depends upon the distance to the surface x as D(x) varies as exp(1/x). The size effect characteristic depth was found to be l approximately=1 nm for the pair under study.