Chiral-angle distribution for separated single-walled carbon nanotubes.

Sato, Yuta; Yanagi, Kazuhiro; Miyata, Yasumitsu; Suenaga, Kazu; Kataura, Hiromichi; Iijima, Sumio · Nano Lett · 2008

basic_science · Level V

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Abstract

Chiral indices (n, m) of metallic and semiconducting single-walled carbon nanotubes (SWNTs) selectively separated via the density-gradient ultracentrifugation process were individually assigned by using an aberration-corrected transmission electron microscope (TEM) operated at 80 kV. Our statistical analysis revealed that armchair (n, n) and chiral (n, n-3) SWNTs with large chiral angles (>20 degrees) are dominant metallic nanotubes in the separated samples, whereas such a noticeable preference of particular indices was not observed for semiconducting nanotubes. Some significant discrepancies were found between the TEM and spectroscopic results on the major chiral indices and the metal/semiconductor ratios in these SWNTs.

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