Synthesis of carbon nanotube peapods directly on Si substrates

Carbon nanotubes encapsulating fullerenes, peapods, have been synthesized directly on Si substrates. High-density and high-quality singe-walled carbon nanotubes (SWNTs) were grown on a SiO2/Si substrate by dip-coating of metal acetate solution and alcohol chemical vapor deposition technique. The caps of SWNTs were opened by annealing in dry air. Then, fullerene doping into the SWNTs was performed by vapor phase doping technique. Encapsulations of C-60 and Gd@C-82 were confirmed by transmission electron microscopy. Raman scattering spectroscopy was performed for synthesized peapods. From Raman scattering spectroscopy of synthesized peapods, the smallest diameters of the SWNTs capable of fullerene encapsulation were estimated to be 1.28 nm for C-60 and 1.43 nm for Gd@C-82. (C) 2005 American Institute of Physics.