In situ sequential STM imaging of structural changes resulting from the electrodissolution of silver crystal surfaces in aqueous perchloric acid : The roughening kinetics
Structural changes of silver terrace domains in aqueous perchloric acid solution at constant anodic current density (j) and room temperature were followed by <i>in situ</i> scanning tunneling microscopy sequential imaging. For j<15 μA cm<sup>-2</sup> silver electrodissolut...
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| Autores principales: | , , , , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
| Publicado: |
1996
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| Materias: | |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/121346 |
| Aporte de: |
| Sumario: | Structural changes of silver terrace domains in aqueous perchloric acid solution at constant anodic current density (j) and room temperature were followed by <i>in situ</i> scanning tunneling microscopy sequential imaging. For j<15 μA cm<sup>-2</sup> silver electrodissolution proceeds at step edges without roughening. Conversely, for j<15 μA cm<sup>-2</sup> the silver surface becomes progressively rougher to attain, after a certain critical time, a steady roughness. In this case, the dynamic scaling theory applied to STM images indicates that the dissolving silver surface can be described as a self-affine fractal surface with a static roughening exponent α50.9060.06, and a dynamic roughening exponent β50.3660.08. The value of a is consistent with the relevant role played by surface diffusion in the silver electrodissolution mechanism, whereas the value of b is slightly higher than those derived from growth models incorporating surface diffusion. The difference in the value of β would reflect the influence of either the electric field or energetic barriers at step edges on the rate of roughness development. |
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