Experimental evidence for kinetically determined intermixed Volmer-Weber growth in thin-film deposition of Au on Ag(110)

Au films, from the submonolayer range up to 11 ML, have been deposited in s itu at 300 K. The geometrical structures of these films have been investiga ted combining full-hemispherical x-ray photoelectron diffraction, low-energ y electron diffraction (LEED), low-energy ion-scattering spectroscopy, and scanning tunneling microscopy leading to an intermixed Volmer-Weber growth model. The results demonstrate that below 0.5 ML most Au atoms are buried w ithin the second substrate layer, forming inverted Ag/Au areas on the surfa ce. The ejected Ag atoms and vacancies created during the Au-Ag exchange nu cleate into elongated two-dimensional Ag islands and vacancy clusters, resp ectively, quickly breaking up the surface into smaller terraces. Above abou t 0.5-ML coverage, the Au-Ag exchange mechanism continues to be active. In addition,due to the reduced mobility of Au atoms deposited on inverted Ag/A u areas, one-dimensional Au stripes as well as elongated three-dimensional (1 x 3)-symmetric Au islands are observed already at submonolayer coverages on inverted Ag/Au areas. Only after the deposition of more than 8-ML Au is the Ag substrate completely covered, and missing-row reconstructed terrace s extend over regions large enough to yield a well-defined 1 x 2 LEED patte rn. The growth model is compared to both, published thermodynamic equilibri um predictions and molecular-dynamics simulations, revealing that the Au/Ag (110) growth system is kinetically determined. [S0163-1829(99)01823-8].