Influence of the electrochemical potential on energy landscapes near step- and island-edges: Ag(100) and Ag(111)

Autor: Theodore L. Einstein, Michael I. Haftel
Rok vydání: 2001
Předmět:
Zdroj: Applied Surface Science. :49-54
ISSN: 0169-4332
Popis: The electrochemical cell offers the promise of enabling controlled alteration of the morphology and islanding phenomena on metallic surfaces. Different diffusion processes near step and island edges are known to profoundly affect the growth mode, island sizes, island shapes and step morphology. Using the surface-embedded-atom model (SEAM) modified for the electrolytic environment, we calculate the dependence of the activation energies for these diffusion processes on the electrochemical potential for the Ag(100) and Ag(111) surfaces. While all these processes show some degree of dependence on the potential, the step-edge barrier and the edge diffusion processes are the most sensitive. Step-edge barriers for Ag(111) increase (to over 1 eV) with a 1.0 V potential (relative to the potential of zero charge (PZC)). The variations for Ag(100) are not as large (about 0.3 eV), but the excess step-edge barrier can be negative for high positive (>+0.6 V) or negative (
Databáze: OpenAIRE