Oxygen-plasma-generated CuOx nanoparticles enhanced the carriers injection from indium-tin oxide (ITO) anode into organic materials. Atomic force microscopy images revealed that the CuOx nanoparticles appeared as high-ordered nanotip arrays on substrates. Those nanoparticles induced strong field-emission current. The analysis by X-ray diffraction pattern and Fourier transform infrared spectrum demonstrated that CuOx was actually of a mixture of copper and copper oxides (CuO, CuO2, CuO3, and CuO4).