Direct Oxidation Growth of CuO Nanowires from Copper‐Containing Substrates

Abstract

Controlling the growth of semiconducting nanowires with desired properties on a reproducible basis is of particular importance in realizing the next‐generation electronic and optoelectronic devices. Here, we investigate the growth of cupric oxide (CuO) nanowires by direct oxidation of copper‐containing substrates at 500 ∘ C for 150 minutes at various oxygen partial pressures. The substrates considered include a low‐purity copper gasket, a high‐purity copper foil, compacted CuO and Cu 2 O thin layers, and layered Cu/CuO and Cu/Cu 2 O substrates. The morphology, composition, and structure of the product CuO nanowires were analyzed using scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, transmission electron microscopy, selected area electron diffraction, X‐ray diffraction, and UV‐Visible absorption. Selected oxidation processes have been monitored using a thermogravimetric analyzer. The layering structure of the substrate after oxidation was analyzed to elucidate the growth mechanism of CuO nanowires.