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Proceedings Paper

Aspects of nanoparticle formation during pulsed laser ablation
Author(s): Richard F. Wood; Jean-Noel G. LeBoeuf; David B. Geohegan; Alexander A. Puretzky; Kuan-Ren Chen
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Paper Abstract

Laser ablation is one of the most effective ways of making single-wall carbon nanotubes. Although the process is poorly understood, the importance of nanoparticle formation to initiate tube growth is evident. While some groups have concluded that nanoparticles can form in vacuum, we have argued that this is unlikely because the expansion of the plume is so rapid that the 'freezing limit' is reached too rapidly for nucleation and growth to the observed size. A background gas changes the dynamics completely. Calculations show that in a few microseconds the ablated plume is dramatically slowed by the 'snowplowing' of the background gas into a peak whose density is much greater than its initial density. The ablated material is trapped within this peak. The question then arises as to how this peak dissipates by diffusion. A simple calculation shows that it is at this point that a drastic change in the timescale of the process occurs so that there is ample time (milliseconds) for nanoparticles to nucleate and grow.

Paper Details

Date Published: 23 March 2000
PDF: 9 pages
Proc. SPIE 3935, Laser Plasma Generation and Diagnostics, (23 March 2000); doi: 10.1117/12.380807
Show Author Affiliations
Richard F. Wood, Oak Ridge National Lab. (United States)
Jean-Noel G. LeBoeuf, Univ. of California/Los Angeles (United States)
David B. Geohegan, Oak Ridge National Lab. (United States)
Alexander A. Puretzky, Oak Ridge National Lab. (United States)
Kuan-Ren Chen, National Cheng Kung Univ. (Taiwan)


Published in SPIE Proceedings Vol. 3935:
Laser Plasma Generation and Diagnostics
Richard F. Haglund; Richard F. Wood, Editor(s)

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