Abstract
The initial stages of Cd electrodeposition on a herringbone reconstructed Au(111) surface from sulfuric acid solution were investigated with an electrochemical scanning tunneling microscope. A novel type of site-selective nucleation of Cd clusters was observed in the underpotential region starting at 330 mV positive to the Nernst potential for Cd bulk deposition. Distinct dots of monoatomic height are formed. In this underpotential regime nucleation proceeds exclusively at the elbow sites of the Au(111) herringbone reconstruction leading to a self-organized surface patterning consisting of nanoscale Cd islands with well-defined separations between. The observation of the site-selective underpotential-controlled electrodeposition of Cd island arrays opens new perspectives for electrochemically generated quantum dots. (C) 2003 The Electrochemical Society.