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lowed by the further gallium deposition at B on the just-formed
phase. The first process (A) is presumably correlated with the for-
mation of a Au–Ga surface alloy. XPS of bulk layers exhibits gallium,
carbon and fluorine due to some residues from the ionic liquid and
some oxygen due to exposure to air. In situ STM images evidence
that Ga is electroless deposited on the Au surface. When the initial
OCP (−0.2 V) is kept constant the gold surface is completely cov-
ered by Ga. The deposit consists of small islands of 50–100 nm in
width and 2–5 nm in height. If the electrode potential is reduced
the deposit grows further. An in situ I/U tunneling spectrum of
the deposit gives typical metallic behavior. The gallium electro-
less deposition was found to depend on the nature of the electrode.
No Ga deposit was observed when glassy carbon or platinum was
employed as electrodes. However Ga electroless deposition took
place on gold. This suggests that the anodic reaction involves gold
oxidation although the oxidation of the ionic liquid can currently
not be excluded totally. Further experiments have to be carried out
in order to elucidate the mechanism of the electroless deposition
of gallium on Au(1 1 1).
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Acknowledgements
L.H.S. Gasparotto thanks Coordenac¸ ão de Aperfeic¸ oamento de
Pessoal de Nível Superior (CAPES) and Fundac¸ ão de Amparo à
Pesquisa do Estado de São Paulo (FAPESP) for a scholarship.
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