STM-SEM and impedance characterization of columnar structured gold electrodes
The impedance spectra of thin gold electrodeposits with 10<sup>−6</sup>−10<sup>−5</sup> cm average columnar radius and 4×10<sup>−6</sup>−3×10<sup>−4</sup> cm average height have been measured in acid solutions. Frequency dispersion has been observed fo...
| Authors: | , , , , |
|---|---|
| Format: | article |
| Status: | Published version |
| Publication Date: | 1991 |
| Country: | Argentina |
| Institution: | Universidad Nacional de La Plata |
| Repository: | SEDICI (UNLP) |
| Language: | English |
| OAI Identifier: | oai:sedici.unlp.edu.ar:10915/122609 |
| Online Access: | http://sedici.unlp.edu.ar/handle/10915/122609 |
| Access Level: | Open access |
| Keyword: | Ciencias Exactas Química Impedance Gold electrodes |
| Summary: | The impedance spectra of thin gold electrodeposits with 10<sup>−6</sup>−10<sup>−5</sup> cm average columnar radius and 4×10<sup>−6</sup>−3×10<sup>−4</sup> cm average height have been measured in acid solutions. Frequency dispersion has been observed for film thicknesses greater than 3 × 10<sup>−5</sup> cm and electrolyte resistivities larger than 300 Ω cm<sup>−1</sup>. STM-SEM observations reveal a self-affine surface structure with a size distribution of pores ranging from 10<sup>−6</sup> to 10<sup>−4</sup> cm between the columnar elements. In diluted solutions the contribution of the smallest pores to the sampled electrode area decreases as ω increases explaining the observed frequency dispersion. This result confirms that self-affine surfaces exhibit a fractional-power-law impedance. However, no simple correlation was found between the α value and the D value of the self-affine surface measured by an independent method. The present results also show that the electrolyte resistivity plays a certain role in determining the α value. |
|---|