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Nitrogen controlled iron catalyst phase during carbon nanotube growth

Autor(en)
Bernhard C. Bayer, Carsten Baehtz, Piran R. Kidambi, Robert S. Weatherup, Clemens Mangler, Jani Kotakoski, Caroline J. L. Goddard, Sabina Caneva, Andrea Cabrero-Vilatela, Jannik C. Meyer, Stephan Hofmann
Abstrakt

Close control over the active catalyst phase and hence carbon nanotube structure remains challenging in catalytic chemical vapor deposition since multiple competing active catalyst phases typically co-exist under realistic synthesis conditions. Here, using in-situ X-ray diffractometry, we show that the phase of supported iron catalyst particles can be reliably controlled via the addition of NH3 during nanotube synthesis. Unlike polydisperse catalyst phase mixtures during H2 diluted nanotube growth, nitrogen addition controllably leads to phase-pure γ-Fe during pre-treatment and to phase-pure Fe3C during growth. We rationalize these findings in the context of ternary Fe-C-N phase diagram calculations and, thus, highlight the use of pre-treatment- and add-gases as a key parameter towards controlled carbon nanotube growth.

Organisation(en)
Physik Nanostrukturierter Materialien
Externe Organisation(en)
University of Cambridge, Helmholtz-Zentrum Dresden-Rossendorf
Journal
Applied Physics Letters
Band
105
Anzahl der Seiten
5
ISSN
0003-6951
DOI
https://doi.org/10.1063/1.4897950
Publikationsdatum
10-2014
Peer-reviewed
Ja
ÖFOS 2012
210006 Nanotechnologie, 103008 Experimentalphysik, 103009 Festkörperphysik
Schlagwörter
ASJC Scopus Sachgebiete
Physics and Astronomy (miscellaneous)
Link zum Portal
https://ucrisportal.univie.ac.at/de/publications/8140e3eb-bd25-4772-9e36-8b21c33c9cb7