Spatial and Contamination-Dependent Electrical Properties of Carbon Nanotubes.
Nano Lett
; 18(2): 695-700, 2018 02 14.
Article
in En
| MEDLINE
| ID: mdl-29257695
ABSTRACT
Two-point probe and Raman spectroscopy have been used to investigate the effects of vacuum annealing and argon bombardment on the conduction characteristics of multiwalled carbon nanotubes (MWCNTs). Surface contamination has a large effect on the two-point probe conductivity measurements which results in inconsistent and nonreproducible contacts. The electric field under the contacts is enhanced which results in overlapping depletion regions when probe separations are small (<4 µm) causing very high resistances. Annealing at 200 and 500 °C reduced the surface contamination on the MWCNT, but high resistance contacts still did not allow intrinsic conductivity measurements of the MWCNT. The high resistance measured due to the overlapping depletion regions was not observed after annealing to 500 °C. Argon bombardment reduced the surface contamination more than vacuum annealing at 500 °C but caused a slight increase in the defects concentration, enabling the resistivity of the MWCNT to be calculated, which is found to be dependent on the CNT diameter. The observations have significant implications for future CNT-based devices.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Nano Lett
Year:
2018
Document type:
Article
Affiliation country:
Reino Unido