Web Release Date: November 21,
Coaxial Nanocables of AlN Nanowire Core and Carbon/BN Nanotube Shell
and
Institute of New Energy Material Chemistry, Institute of Scientific Computing, Nankai University, Tianjin 300071, People's Republic of China, and Department of Theoretical Molecular Science, Institute for Molecular Science, Myodaiji, Okazaki 444-8585, Japan
Received: August 3, 2007
In Final Form: October 1, 2007
Abstract:
Using density functional theory (DFT), we investigated the nanocable models comprised of AlN crystalline nanowires as cores and single-walled carbon nanotubes (SWCNTs) or BN nanotubes (BNNTs) as shells. The AlN@SWCNT nanocable is assembled by a weak van der Waals interaction. The optimum tube-wire distance is ~0.35 nm with an insertion energy of 0.07 eV per AlN. Accordingly, the band structures are superpositions of those of their separate components. The insertion of the AlN nanowire inside BNNTs is more favorable than that inside SWCNTs with comparable diameters. The most favorable case for AlN@BNNT shows that the tube-wire distance is ~0.30 nm and that the insertion energy is 0.09 eV per AlN. The insertion narrows the band gap of AlN nanowires by ~0.21 eV. Exothermic insertion can also be realized at the tube-wire distance of ~0.22 nm by the formation of strong bonding between AlN nanowires and BNNTs, and this nanocable is changed into a p-type semiconductor. The interaction revealed in the present nanocable models is helpful for understanding other inorganic compound nanowire-nanotube hybrid systems.
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