TEM micrographs of raw MWNTs synthesized at CVD growth temperatures of (a) 750 °C and (b) 850 °C. These micrographs illustrate the difference in nanotube diameters present at each growth temperature. The red arrow in Fig. 1(b) points to an iron catalyst particle that has become entrapped in the hollow core of a MWNT.
MWNT diameter distributions for nanotubes synthesized at CVD growth temperatures ranging from 650 °C to 950 °C. The distributions have been normalized from the raw count data and bin size. Note the different y-axis scales of (a) 0%–16% and (b) 0%–1.6% and x-axis scales of (a) 0–50 nm and (b) 0–300 nm.
XPS spectra of the raw and acid treated MWNTs synthesized at 750 °C and 850 °C representing both p-type TEP (750 °C) and n-type TEP (850 °C) showing C 1s and O1 s peaks along with oxygen concentrations.
Seebeck coefficient versus CVD growth temperature for both raw and acid treated (AT) MWNTs, and electrical conductivity versus CVD growth temperature for raw MWNTs.
(a) Seebeck coefficient versus absolute temperature for raw and acid treated (AT) MWNTs at select CVD growth temperatures. (b) Electrical conductivity versus absolute temperature for raw MWNTs grown at 750 °C and 850 °C.
Article metrics loading...
Full text loading...