In situ imaging and spectroscopy of single-wall carbon nanotube synthesis by laser vaporization
- Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
The synthesis of single-wall carbon nanotubes by Nd:YAG laser vaporization of a graphite/(Ni, Co) target is investigated by laser-induced luminescence imaging and spectroscopy of Co atoms, C{sub 2} and C{sub 3} molecules, and clusters at 1000 degree sign C in flowing 500 Torr Ar. These laser-induced emission images under typical synthesis conditions show that the plume of vaporized material is segregated and confined within a vortex ring which maintains a {approx}1 cm3 volume for several seconds. Using time-resolved spectroscopy and spectroscopic imaging, the time for conversion of atomic and molecular species to clusters was measured for both carbon (200 {mu}s) and cobalt (2 ms). This rapid conversion of carbon to nanoparticles, combined with transmission electron microscopy analysis of the collected deposits, indicate that nanotube growth occurs over several seconds in a plume of mixed nanoparticles. By adjusting the time spent by the plume within the high-temperature zone using these in situ diagnostics, single-walled nanotubes of controlled length were grown at an estimated rate of 0.2 {mu}m/s. (c) 2000 American Institute of Physics.
- OSTI ID:
- 20215030
- Journal Information:
- Applied Physics Letters, Vol. 76, Issue 2; Other Information: PBD: 10 Jan 2000; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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