In this work the fabrication and characterization of boron-doped diamond (BDD) nanoelectrode arrays
are discussed. The use of boron-doped diamond electrodes is very attractive due to advantageous properties
including high reproducibility, stability, and robustness under extreme conditions, where conventional
electrode materials may undergo severe erosion. BDD electrodes have also proved to be very useful
because they show an extremely wide potential window in aqueous solutions without oxidation of the
electrode itself. This allows electrochemical detection, at tiny background currents, of a number of substances
that oxidize at very positive potentials, where other electrodic materials are not suitable. BDD
based NEAs were prepared using Si h100i substrates coated with a layer of Boron doped diamond as macroelectrode.
NEAs were obtained by creating an array of nanoholes by electron beam lithography (EBL) in
a thin film of polycarbonate deposited on top of the macroelectrode. This approach leads to the formation
of recessed nanoelectrodes. The parameters for using polycarbonate as a novel electron beam resist have
been optimized and successfully used for fabrication of NEAs. The most interesting properties of this
polymer for nanofabrication purposes are the high lithographic contrast, which allows the creation of
structures of dimensions less than 100 nm; chemical stability, which guarantees a long-term use in electrochemical
solutions and the possibility of functionalization with biological molecules (DNA and proteins).
NEAs have been characterized with cyclic voltammetry and have provided voltammetric signals
controlled by pure radial diffusion. The low background current of BDD added to the properties of NEAs
indicate that this system can be applied for the development of sensors with high sensitivity. Polycarbonate
surface of NEAs was successfully functionalized with small ss-DNA sequence, confirming the possibility
of exploiting these systems as diagnostic biosensors.
