|
|
ELECTROCHEMICAL CHARACTERIZATION OF THE ELECTRODEPOSITION OF GOLD IN NANOPORES AND THEIR SUITABILITY AS NANOELECTRODE ARRAYS
Belen Bello-Rodriguez and Achim Walter Hassel
Max-Planck-Institut für Eisenforschung, Max-Planck-Str. 1
40237 Düsseldorf, Germany
E-mail: bello@mpie.de
|
|
The use of nanoelectrodes offers a great number of advantages in electroanalytical chemistry. Nanoelectrodes are
usually fabricated by template-directed synthesis, involving the chemical or electrochemical deposition of the wires.
Alternatively, an effective route for the fabrication of self-organised nanostructures has been demonstrated with the
use of directionally solidified eutectics [1, 2]. NiAl-X (X = Re, W, Mo) eutectics were used as templates for the
electrodeposition of gold micro- and nano-structures. In these eutectics, the minor components (Re, W, Mo) are
present as fibres uniformly distributed in a stable NiAl matrix. A polarization of the samples at a neutral pH
allows the dissolution of the fibres alongside the passivation of the matrix due to the formation of stable Al2O3
for all three systems studied. The mechanism of gold deposition was studied by examining the current transients
recorded after the application of reverse pulses of different lengths to the passivated samples. In an initial stage,
the nucleation takes place in the pores, until their complete filling. The application of further pulses results in a
diffusion controlled growth of the gold structures [3]. By carefully controlling the duration of the pulses, it is
possible to control the electrodeposition of gold to take place exclusively in the pores, thus enabling the
fabrication of arrays of gold nanoelectrodes. Gold microelectrodes can be obtained after longer deposition times
(Fig.1).
1. A. W. Hassel, B. Bello Rodriguez, S. Milenkovic, A. Schneider, Electrochim. Acta. 50 (2005) 3033-3039.
2. A. W. Hassel, B. Bello Rodriguez, S. Milenkovic, A. Schneider, Electrochim. Acta. 51 (2005) 795-801.
3. B. Bello Rodriguez, A. Schneider, A. W. Hassel. J. Electrochem. Soc. In press.
Fig. 1: Au microelectrodes obtained by electrodeposition on Re nanowires.
|
|