In-situ studies of the catalysis and growth of single-walled nanotubes.

We are conducting a combined experimental and theory project to explore the catalytic growth of single-walled carbon nanotubes (SWCNTs).

Renu Sharma is using the state-of-the-art Tecnai F-20 in-situ TEM in the Center For Solid State Science, with a model catalytic system, made of they Ni nanoparticles deposited by in-situ Electron Beam Induced Deposition (EBID) of nickelocene on thin amorphous SiO2. Particle size is controlled by the electron dose, and the location and distribution on the substrate can be controlled. Acetylene is the precursor gas for in-situ catalytic creation of single walled carbon nanotubes on the tailor-made catalyst.

Preliminary studies show that single-walled carbon nanotubes can be synthesized in-situ while being videotaped at high resolution (see above). Those preliminary studies have revealed an exciting wealth of structural and catalytic details relating to the catalytic growth of single-walled carbon nanotubes (SWCNTs). The SWCNTs are frequently observed to be bent, sometimes resembling random walks. The density of bends is found to depend on acetylene partial pressure (up to 2 Torr), with the straightest SWCNTs occurring at the lowest partial pressures.

In addition, preliminary studies show that the EBID method for depositing controlled size arrays of monodisperse particles, such as GaN, works well in the Tecnai F-20 environmental microscope.To complement the experiments, In collaboration with Peter Rez, we are developing models of the SWCNT structures, and their growth characteristics as a function of precursor pressure, temperature and catalyst particle structure. A 64-processor, 2.8 GHz, Beowulf computer cluster is available for executing the computer-intensive ab-initio codes.

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Last updated July 3rd, 2005.

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