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

Shen, Mingmin
Russell, Selena
Thiel, Patricia
Liu, Da-Jiang
Thiel, Patricia
Journal Title
Journal ISSN
Volume Title
Research Projects
Organizational Units
Organizational Unit
Journal Issue

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 AgS2 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).

<p>Reprinted with permission from <em>The Journal of Physical Chemistry C</em> 135, no. 15 (2011): 154701, doi:<a href="" target="_blank">10.1063/1.3635777</a>. Copyright 2011 American Chemical Society.</p>
Ames Laboratory, Materials Science and Engineering, adsorption, diffusion barriers, island structure, monolayers, nanostructured materials, silver, sulphur