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Iowa State University

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Materials Science and Engineering

Silver

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Articles 1 - 4 of 4

Full-Text Articles in Physics

Communication: Structure, Formation, And Equilibration Of Ensembles Of Ag-S Complexes On An Ag Surface, Selena M. Russell, Yousoo Kim, Da-Jiang Liu, James W. Evans, Patricia A. Thiel Jan 2013

Communication: Structure, Formation, And Equilibration Of Ensembles Of Ag-S Complexes On An Ag Surface, Selena M. Russell, Yousoo Kim, Da-Jiang Liu, James W. Evans, Patricia A. Thiel

Chemistry Publications

We have utilized conditions of very low temperature (4.7 K) and very low sulfur coverage to isolate and identify Ag-S complexes that exist on the Ag(111) surface. The experimental conditions are such that the complexes form at temperatures above the temperature of observation. These complexes can be regarded as polymeric chains of varying length, with an Ag4S pyramid at the core of each monomeric unit. Steps may catalyze the formation of the chains and this mechanism may be reflected in the chain length distribution.


Creating Nanoscale Ag Patterns On The Si(111)–(√3 × √3)R30°-Ag Surface Via Guided Self-Assembly, Alex Belianinov, Barış Ünal, Michael C. Tringides, Patricia A. Thiel Jul 2012

Creating Nanoscale Ag Patterns On The Si(111)–(√3 × √3)R30°-Ag Surface Via Guided Self-Assembly, Alex Belianinov, Barış Ünal, Michael C. Tringides, Patricia A. Thiel

Chemistry Publications

Patterns of Ag nanostructures can be created on the Si(111)–(√3 × √3)R30°-Ag surface, using a simple two-step process in ultrahigh vacuum. First, patterns are created using the tip of a scanning tunneling microscope. Second, Ag is deposited at room temperature. The Ag diffuses over long distances on the surface and selectively aggregates at the patterned regions. The size of the Ag features is ∼3–4 nm.


Destabilization Of Ag Nanoislands On Ag(100) By Adsorbed Sulfur, Mingmin Shen, Selena M. Russell, Da-Jiang Liu, Patricia A. Thiel Jan 2011

Destabilization Of Ag Nanoislands On Ag(100) By Adsorbed Sulfur, Mingmin Shen, Selena M. Russell, Da-Jiang Liu, Patricia A. Thiel

Chemistry Publications

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-Temperature Adsorption Of H2s On Ag(111), Selena M. Russell, Da-Jiang Liu, Maki Kawai, Yousoo Kim, Patricia A. Thiel Jan 2010

Low-Temperature Adsorption Of H2s On Ag(111), Selena M. Russell, Da-Jiang Liu, Maki Kawai, Yousoo Kim, Patricia A. Thiel

Chemistry Publications

H2S forms a rich variety of structures on Ag(111) at low temperature and submonolayer coverage. The molecules decorate step edges, exist as isolated entities on terraces, and aggregate into clusters and islands, under various conditions. One type of island exhibits a (×)R25.3° unit cell. Typically, molecules in the clusters and islands are separated by about 0.4 nm, the same as the S–S separation in crystalline H2S. Density functional theory indicates that hydrogen-bonded clusters contain two types of molecules. One is very similar to an isolated adsorbed H2S molecule, with both ...