Visible cathodoluminescence from carbon nanotubes: the role of impurities

Abstract

Abstract Luminescence spectra obtained by electron bombardment (cathodoluminescence, CL) on bundles of pristine single walled (SWCNT) and multi walled carbon nanotubes (MWCNT) show several common peaks at 1.76, 1.94, 2.06, and 2.22 eV which disappear after heating the samples up to 1300 K. We show that these transitions are extrinsic to nanotubes and originate from nickel oxide impurities, residual catalyst material used in the growth processes. Our conclusions are confirmed by X‐ray photoelectron spectroscopy (XPS) and energy dispersed X‐ray analysis measurements. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)