Copper surfaces influence the growth of copper oxide nanowires

Scientists of the Material Center Leoben, the Department of Material Physics of the Montanuniversitaet Leoben, and Gerhard Popovski of the Institute of Physics have shown that different copper surfaces will influence the growth of copper oxide nanowires. Small copper grains and high surface roughness promote the growth of these important structures, which are used for example in solar cells or sensors.


Cupric oxide (CuO) nanowires were produced by thermal oxidation of copper surfaces at temperatures up to 450 °C. Three different surfaces, namely a copper foil as well as evaporation deposited copper and an application relevant sputtered copper film on Si(100) substrates were characterized ex-situ before and after the experiment. The development of oxide layers and nanowires were monitored in-situ using grazing incidence small angle X-ray scattering. The number density of nanowires is highest for the sputtered surface and lowest for the surface prepared by evaporation deposition. This can be linked to different oxide grain sizes and copper grain boundary diffusions on the different surfaces. Small grains of the copper substrate and high surface roughness thereby lead to promoted growth of the nanowires.

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