Conditions for the formation of nanostructures on electrode surfaces during atomic scale scratching

Abstract

A nanoscale place selective electrochemical deposition of foreign metals on different single crystal electrodes induced by a scanning tunnelling microscope (STM) tip was achieved by scanning with the STM tip very closely to an electrode surface which is covered by a monolayer of a foreign metal by underpotential deposition (UPD). Measuring the minimal conductance G, which is necessary for generating nanostructures, shows that a point contact between the STM tip and the UPD covered surface is formed. This is considered to be responsible for the tip-induced deposition. On Au(1 1 1) in Cu 2+ containing solutions at potentials positive of submonolayer formation, nanoscale scratches are achieved in this way, whereas in the absence of any foreign metal ions only large defects are introduced under the same conditions.