Novel carbon nanohorns filled with single crystalline Cu nanocones (Cu-CNHs) have been synthesized using alkali-element doped Cu catalyst by CVD. X-ray diffraction (XRD) analysis reveals that Cu nanocones have face-centered cubic structure. Selected area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM) indicate that these Cu nanocones are single crystalline in nature. Based on experimental results, a simple growth model is proposed in this paper. (c) 2007 Elsevier B.V. All rights reserved.