ELECTROCHEMICAL NANOFABRICATIONS: A GENERAL REVIEW - Electrochemical Nanofabrication: Principles and Applications - page 43

route for nanopatterning metal, alloys and oxide surfaces with
high resolution in a simple and inexpensive way. This method
involves electrodeposition onto a conducting master covered by a
alkanethiolate SAMs. This molecular film enables direct surface-relief
pattern transfer from the conducting master to the inner face of the
electrodeposit, and also allows an easy release of the electrodeposited
film due to their excellent anti-adherent properties. Replicas of the
original conductive master can be also obtained by a simple two-
step procedure. SAM quality and stability under electrodeposition
conditions combined with the formation of smooth electrodeposits
are crucial to obtain high-quality pattern transfer with sub-50 nm
resolution. Figure 1. 20 demonstrates the steps involved in metal
electrodeposition on SAMs covered substrates. Further in-depth
investigations are required for improving SAM quality reducing
the defect size and density, and accordingly increasing the lateral
resolution of the method.
Electrochemical work comprised mainly copper deposition
onto alkanethiol SAMs. Under UPD, Cu would go down on the
bare substrate only [212]. The chain length of the alkane thiol
on gold has an influence on the deposition over potential [213].
The long-chain alkane thio (C18) on Au (111) is demonstrated to
have a high blocking power [214]. However, it appears to remain
one of the challenges for the near future to find the experimental
conditions under which metal can be deposited on top of a SAM,
preferably as a 2D overlayer. On the other hand, electrochemistry
can induce self-assembly of surface-templated (organo)silica thin
films on various conducting supports, with mesopore channels
oriented perpendicular to the solid surface over wide areas [215].
This method is intrinsically simple and fast and does not require
any pretreatment of the support. It consists of combining the
electrochemically driven self-assembly of surfactants at solid-liquid
interfaces and an electroassisted generation method to produce sol-
gel films. The method of electrochemically assisted self-assembly of
mesoporous silica thin films involves the application of a suitable
cathodic potential to an electrode immersed in a surfactant-
containing hydrolyzed sol solution to generate the hydroxyl ions that
are necessary to catalyse polycondensation of the precursors and
self-assembly of hexagonally packed one-dimensional channels that