Electrochemical fabrication of nano- and micrometric Cu particles: in situ investigation by electroreflectance and optical second harmonic generation

In this paper the electrochemical fabrication of nano- and micrometric Cu particles from an acidic sulphate electrodeposition bath is reported. The particles were formed directly in the bulk by an electrochemical chemical route, implying electrochemical reduction of Cu(II) to Cu(I) and subsequent disproportionation. Growth of the nuclei present in the catholyte into nano- or micrometric dimensions can proceed either by catalysing Cu(I) disproportionation or by bipolar electrode effects. Observations using TEM highlighted the formation of spheroidal nanoparticles and kinetically faceted micrometric crystals. The initial stages of particle nucleation and growth were monitored by in situ linear (electroreflectance) and non-linear (second harmonic generation) optical spectroelectrochemical measurements carried out during the electrochemical process.