Gas phase synthesis of non-bundled, small diameter single-walled carbon nanotubes with near-armchair chiralities
- Author(s)
- K. Mustonen, P. Laiho, A. Kaskela, Z. Zhu, O. Reynaud, N. Houbenov, Y. Tian, T. Susi, H. Jiang, A. G. Nasibulin, E. I. Kauppinen
- Abstract
We present a floating catalyst synthesis route for individual, i.e., non-bundled, small diameter single-walled carbon nanotubes (SWCNTs) with a narrow chiral angle distribution peaking at high chiralities near the armchair species. An ex situ spark discharge generator was used to form iron particles with geometric number mean diameters of 3-4 nm and fed into a laminar flow chemical vapour deposition reactor for the continuous synthesis of long and high-quality SWCNTs from ambient pressure carbon monoxide. The intensity ratio of G/D peaks in Raman spectra up to 48 and mean tube lengths up to 4 μm were observed. The chiral distributions, as directly determined by electron diffraction in the transmission electron microscope, clustered around the (n,m) indices (7,6), (8,6), (8,7), and (9,6), with up to 70% of tubes having chiral angles over 20°. The mean diameter of SWCNTs was reduced from 1.10 to 1.04 nm by decreasing the growth temperature from 880 to 750°C, which simultaneously increased the fraction of semiconducting tubes from 67% to 80%. Limiting the nanotube gas phase number concentration to ∼10
5cm
-3 prevented nanotube bundle formation that is due to collisions induced by Brownian diffusion. Up to 80% of 500 as-deposited tubes observed by atomic force and transmission electron microscopy were individual. Transparent conducting films deposited from these SWCNTs exhibited record low sheet resistances of 63 Ω/□ at 90% transparency for 550 nm light.
- Organisation(s)
- Electronic Properties of Materials
- External organisation(s)
- Aalto University, Peter the Great St.Petersburg Polytechnic University, Skolkovo Institute of Science and Technology
- Journal
- Applied Physics Letters
- Volume
- 107
- No. of pages
- 5
- ISSN
- 0003-6951
- Publication date
- 07-2015
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103018 Materials physics
- Keywords
- ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/b654a3e1-0be3-4b44-830b-c21a6f586c25