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