Arenal, Raul and Stephan, Odile and Cochon, Jean-Lou and Loiseau, Annick (2007) Root-growth mechanism for single-walled boron nitride nanotubes in laser vaporization technique. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 129 (51). pp. 16183-16189.
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Official URL: http://dx.doi.org/10.1021/ja076135n
We present a detailed study of the growth mechanism of single-walled boron nitride nanotubes synthesized by laser vaporization, which is the unique route known to the synthesis of this kind of tube in high quantities. We have performed a nanometric chemical and structural characterization by transmission electron microscopy (high-resolution mode (HRTEM) and electron energy loss spectroscopy) of the synthesis products. Different boron-based compounds and other impurities were identified in the raw synthesis products. The results obtained by the TEM analysis and from the synthesis parameters (temperature, boron, and nitrogen sources) combined with phase diagram analysis to provide identification of the fundamental factors determining the nanotube growth mechanism. Our experiments strongly support a root-growth model that involves the presence of a droplet of boron. This phenomenological model considers the solubility, solidification, and segregation phenomena of the elements present in this boron droplet. In this model, we distinguish three different steps as a function of the temperature: (1) formation of the liquid boron droplet from the decomposition of different boron compounds existing in the hexagonal boron nitride target, (2) reaction of these boron droplets with nitrogen gas present in the vaporization chamber and recombination of those elements to form boron nitride, and (3) incorporation of the nitrogen atoms at the root of the boron particle at active reacting sites that achieves the growth of the tube.
|Subjects:||Physical Science > Nano objects|
Material Science > Nanostructured materials
Material Science > Nanochemistry
|Deposited By:||Anuj Seth|
|Deposited On:||13 Jan 2009 09:41|
|Last Modified:||20 Jan 2009 14:24|
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