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

Article

关键词: RAY PHOTOELECTRON DIFFRACTION;    SCANNING-TUNNELING-MICROSCOPY;    ENERGY ION-SCATTERING;    ATOMIC EXCHANGE;    MULTILAYER RELAXATION;    INITIAL GROWTH;    STEP DYNAMICS;    SURFACE;    RECONSTRUCTION;    DIFFUSION;   

DOI  :  10.1103/PhysRevB.59.15975

来源: SCIE

【 摘 要 】

Au films, from the submonolayer range up to 11 ML, have been deposited in situ at 300 K. The geometrical structures of these films have been investigated combining full-hemispherical x-ray photoelectron diffraction, low-energy 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 within the second substrate layer, forming inverted Ag/Au areas on the surface. The ejected Ag atoms and vacancies created during the Au-Ag exchange nucleate into elongated two-dimensional Ag islands and vacancy clusters, respectively, quickly breaking up the surface into smaller terraces. Above about 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/Au 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 terraces extend over regions large enough to yield a well-defined 1 x 2 LEED pattern. The growth model is compared to both, published thermodynamic equilibrium predictions and molecular-dynamics simulations, revealing that the Au/Ag(110) growth system is kinetically determined. [S0163-1829(99)01823-8].

【 授权许可】

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