Abstract
One-dimensional well-ordered CuO nanofibers have been synthesized by electrodposition followed by the self-catalytic growth. Firstly, the nuclei sites of copper were distributed uniformly on copper substrate, using polycarbonate (PC) template and high operation-voltage input (electric field is 15 V/cm) in a copper sulphate solution. According to pore diameter of PC membrane, two different sizes of copper nuclei could be well controlled at 50-60 and 100-150 nm.With after-treatment in oxidation reaction, the electrodeposited copper nuclei have been transformed into the nanofibers of the copper oxide. The characteristics of nanofibers were examined by X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Results showed that the highly ordered CuO nanofibers had a mean length of 6-8 μm, and their average diameters were accorded with pore size of PC membrane. The band gap of the CuO nanofibers was calculated to be 1.67 eV from the photoluminescence (PL) absorption spectrum, which is apparently smaller than the reported value for the bulk CuO (Eg = 1.85 eV)Typical turn-on voltage for the CuO nanofiber arrays was detected at about 6-7 V/μm with an emission area of 1 mm2. The Fowler-Nordheim model was employed to analyze the I-V data obtained. The work function of the nanofibers was estimated in range of 3.1-4.3 eV. Based on the above analyses, the highly-ordered CuO nanofiber array can be a promising candidate as field emission emitters.