In operando GISAXS studies of mound coarsening in electrochemical homoepitaxy.

Kinetic roughening during electrodeposition was studied by grazing incidence small angle x-ray scattering for the case of Au(001) homoepitaxial growth in Cl- containing electrolytes. The formation and coarsening of an isotropic mound distribution on unreconstructed Au(001) and of [110]-oriented anisotropic mounds on the "hex" reconstructed surface was observed. The lateral mound coarsening is described by a well-defined scaling law. On unreconstructed Au a transition in the coarsening exponent from ≈1/4 to ≈1/3 with increasing potential is found, which can be explained by the pronounced potential dependence of surface transport processes in an electrochemical environment.

Anomalous potential dependence in homoepitaxial Cu(001) electrodeposition: an in situ surface x-ray diffraction study.

Homoepitaxial Cu electrodeposition on Cu(001) in chloride-containing electrolyte was studied by time-resolved in situ surface x-ray diffraction at growth rates up to 38 ML/ min. With increasing Cu electrode potential, transitions from step-flow to layer-by-layer and then to multilayer growth are observed. This potential dependence is opposite to that expected theoretically and found experimentally for the Au(001) homoepitaxial electrodeposition [K. Krug et al., Phys. Rev. Lett. 96, 246101 (2006)]. The anomalous behavior is rationalized by a decisive influence of the ordered c(2 × 2)-Cl adlayer on the surface energy landscape, specifically on the effective change in dipole moment during adatom diffusion.

High-speed in situ surface X-ray diffraction studies of the electrochemical dissolution of Au(001).

We present in situ X-ray surface diffraction studies of interface processes with data acquisition rates in the millisecond regime, using the electrochemical dissolution of Au(001) in Cl-containing solution as an example. This progress in time resolution permits monitoring of atomic-scale growth and etching processes at solid-liquid interfaces at technologically relevant rates. Au etching was found to proceed via a layer-by-layer mechanism in the entire active dissolution regime up to rates of ∼20 ML/s. Furthermore, we demonstrate that information on the lateral surface morphology and in-plane lattice strain during the electrochemical process can be obtained.