Hollow to bamboolike internal structure transition observed in carbon nanotube films

Y. Y. Wang, S. Gupta, R. J. Nemanich, Z. J. Liu, L. C. Qin

Research output: Contribution to journalArticle

24 Scopus citations

Abstract

The transition of the internal structure in microwave chemical-vapor- deposited carbon nanotubes is investigated using scanning electron microscopy and high-resolution transmission electron microscopy. By controlling the thickness of the iron catalyst layer, a sequence of carbon nanotube films was obtained with diameters ranging from a few nanometers to over 100 nm. Experiments have established that by continuous reduction of the Fe layer thickness to <1 nm, single- and double-wall carbon nanotube films can be produced, whereas for an Fe film thickness <1 nm, multiwall carbon nanotube films can be synthesized. It was also found that for an Fe thickness ≥5 nm, interlayers (i.e., bamboolike or periodically compartmentalized nanotubes) were formed, while for an iron thickness <2 nm the tubes were primarily hollow. For an intermediate Fe thickness the internal structure of the carbon nanotubes was a mixture of hollow and bamboolike. A growth model which considers bulk and surface diffusions of carbon into andor onto the Fe catalyst surface is proposed to describe this transition and the internal periodic structure.

Original languageEnglish (US)
Article number014312
JournalJournal of Applied Physics
Volume98
Issue number1
DOIs
StatePublished - Jul 1 2005
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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