Bragg intensity oscillations were monitored, by using low-energy electron diffraction techniques, during the growth of Pt films on (100)Pd substrates. Distinct oscillations were observed even at 80K, where thermally activated surface diffusion was negligibly slow. It had previously been shown that the oscillations were consistent with the requirement of a 4-fold hollow absorption site. The experimental data suggested that surface diffusion began at about 150K. A preliminary analysis was made of master equations which incorporated diffusion, and absorption sites. The model predicted that the growth tended to become more layer-by-layer in nature, with the onset of diffusion. It was concluded that the role played by diffusion was complicated, since lateral (intralayer) diffusion led to clustering, to the creation of more adsorption sites, and to a decrease in the tendency to layer-by-layer growth. The effect of interlayer diffusion was to make the growth more layer-by-layer in nature.

J.W.Evans, D.K.Flynn, P.A.Thiel: Ultramicroscopy, 1989, 31[1], 80-6