Local and global electrochemical nanostructuring of Pt and Au single crystal electrodes

Cu deposition at stepped, Pt(111) vicinal surfaces gives rise to three dimensional clusters. Decoration of the monatomic steps decreases the size of the clusters. Furthermore, a confined nanometer scale deposition at monatomic steps has been achieved by combining step decoration and terrace masking (the residual space is masked by adsorption of ethene). The nanoclusters deposited at steps of Pt(111) are ∼7 nm in diameter and three to five monatomic layers high, while on Pt(665) the width of nanostripes is given by the terrace width of the substrate. A local nanostructuring of the electrode surface was obtained by scanning with the STM tip very closely to the substrate covered by metallic (UPD) adlayers. Such a tip induced alloy formation was found for the following systems: Pt(111)/Cu, Pt(100)/Cu, Pt(111)/As, Au(111)/Cu and Au(111)/Pd. It turns out that at the critical distance for the nanostructuring the conductance between tip and surface is given by that of a quantum nanowire