Nanostructuring of a sodium dodecyl sulfate-covered Au(111) electrode

Abstract

In situ scanning tunneling microscopy (STM) and electrochemical measurements were used to investigate the properties of adsorbed sodium dodecyl sulfate (SDS) on Au(111) in sulfuric acid solutions and the effect of this adlayer on the copper deposition. The results confirm former studies by Burgess et al. that SDS molecules are adsorbed in hemimicellar aggregates (state I) at potentials between E_SCE = −0.2 and +0.3 V and they form a condensed layer at E_SCE > +0.45 V (state II). The adsorbed SDS film represents a kinetic barrier for the copper deposition. With the tip of the STM it is possible to remove the tarnishing SDS film in a predetermined area and thus make this area available for copper bulk deposition. In this way, the electrode was nanostructured with copper clusters and copper lines without harming the gold surface. In this preliminary study, the influence of the tunneling current and other parameters, which affect the nanostructuring process, is presented.