STM OBSERVATIONS OF 2-DIMENSIONAL CONDENSED LAYERS ON SOLID ELECTRODES

Two-dimensional condensed monolayers formed electrochemically on highly oriented pyrolitic graphite (HOPG) have been imaged using STM techniques. The formation Process involves electrochemical adsorption followed by a phase transition to the condensed state which is controlled by the electrode potential. The resulting layered structures are well ordered and free of defects. In this work, the electrochemistry of condensed layers is briefly reviewed from a thermodynamic perspective. Recent STM studies are discussed and shown to confirm some of the earlier conclusions about condensed monolayer structures. It is also shown that the structure and the composition of a single phase of a condensed layer change, with electrode potential and the composition of the electrolyte for the cases of adenine and guanine on HOPG. Possible applications in the formation of structured films for nanotechnology are discussed.