Аннотация:The present paper is devoted to the influence of the growth temperature of
multi-walled carbon nanotubes (MWCNTs) on their defective structure. The
MWCNTs obtained within the range of 610–750 C have been studied using
two methods: Raman spectroscopy and the analysis of the temperature
dependence of conductivity. This approach allows us to obtain independent
data on the concentration of the defects within the MWCNTs via the intensity
ratio of 2D and D bands, on one hand, and charge carrier concentration, on the
other hand. The results obtained using Raman spectroscopy and the analysis of
the conductivity have provided asymptotic and volcano-like curves, respectively,
of defect concentration within the temperature range studied. This can be
attributed to the difference in the probing depth of each method (50nm for
Raman spectroscopy, and 2–3 nm for conductivity measurements) providing
different sensitivity to surface impurities or defects. The secondary factors (the
size of the active component, the amount of the lateral carbon deposits) have
been shown to mask the influence of the growth temperature. Nevertheless, as
these secondary factors and the synthesis temperature independently affect the
effective nanotube defectiveness, we have shown the defect concentration to
fall with increasing MWCNT growth temperature.
