Copper electrodeposition on alkanethiolate covered gold electrodes

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