Kinetics and Mechanism of Gold Dendrite Electroformation on C(0001) : Activation Energy for Gold Adatom Surface Diffusion
Au electrodeposition on C(0001) from aqueous solutions with different concentrations of AuCl<sub>3</sub>·HCl, at a constant ionic mass transport rate (j<sub>L</sub>), in the temperature range 275 ≤ T ≤ 313 K, results in the initial formation of nanometer-sized Au islands cons...
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| Autores principales: | , , , , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
| Publicado: |
1999
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| Materias: | |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/121476 |
| Aporte de: |
| Sumario: | Au electrodeposition on C(0001) from aqueous solutions with different concentrations of AuCl<sub>3</sub>·HCl, at a constant ionic mass transport rate (j<sub>L</sub>), in the temperature range 275 ≤ T ≤ 313 K, results in the initial formation of nanometer-sized Au islands consisting of a central core and symmetrically distributed branches with the island fractal dimension D<sub>f</sub> = 1.6. For all values of T, the time dependence of the Au island radius fulfills a r ∝ t<sub>n</sub> relationship with n = 0.25 ± 0.05. At constant T, the density of Au islands (N<sub>s</sub>) increases according to N<sub>s</sub> ∝ j<sub>L</sub><sup>X</sup> with X = 0.69 ± 0.03. At constant j<sub>L</sub>, the value of N<sub>s</sub> decreases as T is increased, following an Arrhenius-type relationship. Kinetic data are consistent with a growth mechanism involving surface diffusion of Au adatoms from the island core towards branch tips. From the dependence of N<sub>s</sub> on T at constant j<sub>L</sub>, the activation energy for Au adatom surface diffusion results in E<sub>a</sub><sup>*</sup> ≈ 11 Kcal/mol. This figure is slightly smaller than E<sub>a</sub><sup>*</sup> ≈ 14 Kcal/mol that has been reported for Au atom surface diffusion in Cl<sup>-</sup>-ion free acid solutions. |
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