The controlled construction of nanostructures on solid surfaces for
technological applications depends primarily on a deep understanding of
the physical chemistry of the interface. Several methods have been
devised to grow metallic nanostructures on solid surfaces, notably
physical vapor deposition and electrodeposition. The electrochemical
method led to the creation of a very promising technology called
Electrochemical Step Edge Decoration (ESED) by the Penner group in
Irvine, Ca. In this method, metallic nano and mesowires are built
through electrochemical deposition on the step edges of the basal plane
of Highly Oriented Pyrolytic Graphite (HOPG) [1]. The proposed growth
mechanism is based on the Terrace-Ledge-Kink (TLK) model [2], in which
the foreign adatoms nucleate the electrochemically induced growth of
nanoparticles in the lower plane of step edges. White and collaborators
[3], while studying the stability of gold nanoparticles electrodeposited
on HOPG, noticed the preferential nucleation on the upper plane of step
edges in stark opposition to the TLK model. They proposed that this
preferential deposition is associated with a slippage of the atomic
layer near the edge. This proposition indicates that the surface in the
upper plane near the edge will present a decrease in the atomic distance
in the plane, disrupting the registry with the underlying plane. To
further assess this proposition we have devised another experimental
approach where, instead of electrodepositing foreign adatoms for
nucleation and growth, we deposited fully formed silver nanoparticles on
HOPG through a Self Assembly mechanism and studied its spatial
distribution. Through this approach, we intend to study the surface
mobility of nanoparticles, as opposed to atomic species as studied in
electrochemical deposition.