Field emission characteristics of CuO nanowires grown on brown-oxide-coated Cu films on Si substrates by conductive heating in air

CuO nanowires were grown on brown-oxide-coated Cu films on Si substrates by conductive heating in air and their field emission characteristics were investigated. High resolution scanning electron microscopy showed that the CuO nanowires grew perpendicularly to the substrate, and their length and radius could be controlled by varying heating temperature and time. It was found that the lengths of the CuO nanowires were saturated to a certain point with respect to the heating temperature, and the increasing heating time increased the uniformity of the CuO nanowires in length. The field emission characteristics were strongly affected by the formation of the brown-oxide layer and the morphologies of the CuO nanowires governed by heating temperature and time.