AVS 51st International Symposium
    Nanometer-scale Science and Technology Tuesday Sessions
       Session NS-TuP

Paper NS-TuP12
Evolution of Single-wall Carbon Nanotubes under Atomic and Molecular Deuterium Treatments

Tuesday, November 16, 2004, 4:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: E.G. Keim, University of Twente, MESA+ Institute, The Netherlands
Authors: E.G. Keim, University of Twente, MESA+ Institute, The Netherlands
W. Lisowski, Polish Academy of Sciences, Poland
A.H.J. Van den Berg, University of Twente, MESA+ Institute, The Netherlands
M.A. Smithers, University of Twente, MESA+ Institute, The Netherlands
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Relatively little experimental activity has been devoted to the interaction of atomic hydrogen with single-walled carbon nanotubes (SWNTs). Here we present SEM, TEM and XPS data dealing with the question of how the SWNTs are affected by prolonged interaction with a gas mixture of atomic (D) and molecular deuterium (D@sub 2@) at various temperatures. The material, HiPco, was first dispersed in isopropanol in an ultrasonic bath and was subsequently deposited on Si(100). Both the heating of SWNTs and their interaction with deuterium were performed in situ in a quartz cell, part of a separate UHV glass system@footnote 1@, and maintained at 78 or 273 K. The SWNT samples were exposed to the gas mixture, produced by the thermal dissociation of D@sub 2@ on a hot W filament, its temperature, T@sub f@, being kept at 1020 and 1550 K for a deuterium pressure of 0.005 and 0.5 Torr, respectively. All gas-solid interactions were monitored in situ by Thermal Desorption Mass Spectrometry (TDMS). See Ref.@footnote 2@ for a description. The spectroscopic and microscopic examinations were performed ex situ. Prolonged interaction of the (D + D@sub 2@) gas mixture produced at T@sub f@ = 1020 K leads to a coalescence of bundles of SWNTs forming large diameter carbon ropes of square and triangular cross-section covered by nano-aggregates of graphite material. Both the coalescence of single SWNTs and a massive reconstruction of bundles of SWNTs into multi-walled nanotubes were found to occur after prolonged exposure of the SWNTs to the gas mixture produced at T@sub f@ = 1550 K. Similar evolution phenomena were observed earlier@footnote 3@, however, after annealing the SWNTs under Ar flow above 2000 K. @FootnoteText@ @footnote 1@ W. Lisowski, Vacuum 53, 13 (1999).,@footnote 2@ W. Lisowski, E.G. Keim and M.A. Smithers, J. Vac. Sci. Technol. A21, 545 (2003).,@footnote 3@ K. Méténier, S. Bonnamy, F. Béguin, C. Journet, P. Bernier, M. Lamy de La Chapelle, O. Chauvet, S. Lefrant, Carbon 40, 1765 (2002).