Strain relief during metal-on-metal electrodeposition: a scanning tunneling microscopy study of copper growth on Pt(100)

The galvanic deposition of copper on Pt(100)-(1 × 1) was studied in sulfate electrolyte by means of time-resolved in situ STM and voltammetry. Surprisingly, copper grows layer-by-layer in the absence of strongly adsorbing additives. This behavior persists beyond the deposition of two layers and is thus different from that found in analogous vacuum studies. After deposition of 5 to 10 layers, the deposit relaxes to the copper bulk structure. Due to the CuPt misfit and the geometry of the Pt substrate, this results in a square-shaped moirépattern. For thick layers, the growth proceeds in the usual way, i.e. via three-dimensional clusters.