NUCLEATION AND GROWTH OF BINARY-ALLOYS ON SUBSTRATES

The nucleation and growth of silver-gold alloys on rock-salt cleavage surfaces was investigated systematically by evaporating the two metals from different sources so that the alloy was formed on the substrate surface. Measurements were carried out on the time dependences of the crystallite populations and size distributions and of the composition of the condensed material. It was found that the composition varies strongly with crystallite diameter and with the deposition time. The results were interpreted in terms of an extended kinetic nucleation model from the difference between the single atom adsorption energy and the activation energy for surface diffusion of the components. The adsorption energy for gold on rock-salt was found to be about 0.08 eV higher than for silver, whereas the activation energy for surface diffusion was about 0.02 eV lower for gold than for silver. These results were compared with data from other workers and show some discrepancies which may be due to different surface conditions. © 1979.