Copper electrodeposition on alkanethiolate covered gold electrodes

We have investigated the structure and thermal dynamics of alkanethiolate l ayers on Au(111) with variable temperature scanning tunnelling microscopy ( STM), X-ray photoelectron spectroscopy (XPS) and voltammetry. The results b uild the basis for a study of electrodeposition of copper on alkanethiolate -covered Au(111). Electrodeposition has been studied as a function of the t hiolate chain length, the deposition potential and the temperature. Time-re solved in situ STM and voltammetry, both at temperatures up to 345 K, and X PS of emersed samples showed that copper can - depending on the deposition potential - either form nanometer-sized islands or layers, both without des truction of the thiolate. We propose a mechanism where copper penetrates th e thiolate layer The slow deposition rate is determined only by kinetic fac tors since Cu/Cu2+ exchange processes cannot operate. Finally we discuss th e role of thiolates as preadsorbed surfactants.