Large-area arrays of copper oxide (CuO) nanorods were self-catalyzed and selectively grown on a Cu/TaN/Si assembly by combining vacuum-arc Cu deposition and vapor-solid reaction. X-ray-diffraction spectra showed the peaks of Cu films and CuO nanorods, respectively. Field-emission scanning electron microscopy images showed semialigned CuO nanorods with diameters of ∼40–80 nm. High-resolution transmission electron microscopy images showed the structure of individual CuO nanorods and their  growth direction. Auger electron spectroscopy depth profiles showed the elemental distribution of the CuO/a-TaN/Si assembly. X-ray photoelectron spectrometry identified the chemical nature of the CuO nanorods. Their electron field-emission properties are discussed from the current-density–voltage curves and Fowler-Nordheim plots.