Electrical properties of C4+ irradiated single-walled carbon nanotube paper

Abstract

Single-walled carbon nanotube (SWNT) networks have been irradiated with a C-12(4+) ion beam (ion energy 23 MeV) to investigate changes to their properties. Measurements of the Raman D-line show that the irradiation produces structural defects throughtout SWNT paper of thickness 40 mu m, with a linear increase in defects at the back side of the sample, but a saturating tendency occurring at the front (irradiated) side. The resistance of the samples also increases linearly with irradiation dose. The temperature dependence of the conductivity of the samples is changed progressively by the irradiation, whereas the pristine sample exhibits mixed metallic nonmetallic character consistent with the usual model of metallic conduction interrupted by thin barriers through which fluctuation-assisted tunnelling occurs, the temperature dependence loses its metallic character and follows three dimensional variable-range hopping for the most irradiated sample. (C) 2008 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim