In situ STM study of homoepitaxial electrodeposition on Au(1 0 0)

We have studied by in situ scanning tunneling microscopy the homoepitaxial electrodeposition on reconstructed and partially reconstructed Au(1 0 0) surfaces from chloride-containing solutions. Layer-by-layer, but strongly anisotropic, growth is observed on a completely reconstructed surface. On a partially reconstructed surface nucleation occurs on the unreconstructed areas, but the new islands formed tend to be pinned, growing anisotropically along the borders between reconstructed and unreconstructed areas.

► There exist strong anisotropic effects during homoepitaxial growth on reconstructed Au(1 0 0) electrodes.
► On partially reconstructed Au(1 0 0) electrodes, nucleation occurs on the unreconstructed surface, but the presence of adjacent reconstructed areas has a pronounced effect on the resulting surface morphology, with elongated unreconstructed islands nucleating along trenches up to three layers deep and several reconstruction lines wide.
► When the homoepitaxial growth of Au(1 0 0) and the formation of the electrochemically induced reconstruction occur simultaneously, most of the extra atoms necessary to build up the newly formed reconstruction rows come from the solution, and not from the edges of steps or islands.