Catalysts effect on single-walled carbon nanotube branching

The catalytic effect on the Y-shaped single-walled carbon nanotubes (Y-SWNTs) branching is investigated. The formation of Y-shaped branches is found to be dependent on the catalysts composition, which can be correlated to the Gibbs free energy of metal carbide formation. Easier carbide formers, like Mo or Zr, have a strong tendency to attach to the sidewall of SWNTs, enhancing the degree of carbon nanotube branching. The electrical conductance of the Y-SWNTs demonstrated rectification characteristics at room temperature, which is attributed to the Schottky barrier formed at the junction position. The Y-SWNTs can be used as a building block for future nanoelectronic, sensor and composite. (c) 2007 Elsevier B.V. All rights reserved.