Cu-nanoclusters produced on AuCu-Alloys with an electrochemical scanning tunneling microscope

Abstract

Cu-nanoclusters can be produced in an electrochemical environment by tip-induced metal deposition using an electrochemical scanning tunneling microscope (EC-STM). These clusters, consisting of 100-1000 atoms only, show a surprising stability against anodic oxidation. The clusters, which are 2-3 atomic layers in height dissolve slowly when the applied potential is increased step by step to 200 mV positive of the reversible Nernst potential for ``normal{''} copper dissolution. The presented work gives evidence that the unusual stability of the clusters could be a consequence of interfacial alloying between the cluster and the underlying substrate. In order to study these effects Cu-nanoclusters have been produced on pure gold substrates and on carefully prepared Au3Cu(111)-substrates. This work compares the results obtained on both substrates