Spatially confined copper dissolution by an STM tip: a new type of electrochemical reaction?

With the tip of an STM, Cu can be dissolved from an electrode at potentials at which Cu dissolution should normally not occur. The dissolution process takes place only underneath the tip allowing for a nanometer scale patterning of the Cu surface. The dissolution rate is shown to depend sensitively on the tip potential as well as on the electrode potential. The electrochemical conditions are also given at which the tip influence is negligible and surfaces can be safely imaged. An explanation for the tip-induced metal dissolution on the basis of a direct charge transfer to the tip is offered.