Destabilization of Ag nanoislands on Ag(100) by adsorbed sulfur

TitleDestabilization of Ag nanoislands on Ag(100) by adsorbed sulfur
Publication TypeJournal Article
Year of Publication2011
AuthorsShen MM, Russell SM, Liu DJ, Thiel PA
Journal TitleJournal of Chemical Physics
Date Published10
Type of ArticleArticle
ISBN Number0021-9606
Accession NumberWOS:000296516800041
Keywordsadsorption, ag(111), clusters, diffusion, diffusion barriers, evolution, film growth, initio molecular-dynamics, island structure, metal-surfaces, monolayers, nanostructured materials, oxygen, silver, sulphur

Sulfur accelerates coarsening of Ag nanoislands on Ag(100) at 300 K, and this effect is enhanced with increasing sulfur coverage over a range spanning a few hundredths of a monolayer, to nearly 0.25 monolayers. We propose that acceleration of coarsening in this system is tied to the formation of AgS(2) clusters primarily at step edges. These clusters can transport Ag more efficiently than can Ag adatoms (due to a lower diffusion barrier and comparable formation energy). The mobility of isolated sulfur on Ag(100) is very low so that formation of the complex is kinetically limited at low sulfur coverages, and thus enhancement is minimal. However, higher sulfur coverages force the population of sites adjacent to step edges, so that formation of the cluster is no longer limited by diffusion of sulfur across terraces. Sulfur exerts a much weaker effect on the rate of coarsening on Ag(100) than it does on Ag(111). This is consistent with theory, which shows that the difference between the total energy barrier for coarsening with and without sulfur is also much smaller on Ag(100) than on Ag(111). (C) 2011 American Institute of Physics. [doi:10.1063/1.3635777]

Alternate JournalJ. Chem. Phys.