Nanoscale decoration of electrode surfaces with an STM

The tip of a scanning tunnelling microscope (STM) has been used to deposit nanometer-sized clusters of copper or silver on bare and thiol-covered gold electrode surfaces at predetermined positions. First, metal is deposited e lectrochemically onto the STM tip, then the clusters are formed by a jump-t o-contact between the tip and the substrate during a short and very control led approach of the tip towards the surface. When Ni is deposited onto the tip, the jump-to-contact occurs in the opposite direction leaving holes in the gold surface. The stability of the metal clusters against anodic dissol ution is discussed. Finally, it is shown how the tip approach can be used t o determine tunnel barriers at the metal-electrolyte interface. (C) 2000 El sevier Science B.V. All rights reserved.