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Evolution of the Raman intensity and the transport properties of SWNTs in various electrochemical doping stages – Exciton effects and functionalization‐induced DOS changes
Author(s) -
Rafailov Peter M.,
Monev Milko,
Bretzler Rita,
Evtimova Svetla,
Arnaudov Boris,
Thomsen Christian,
DettlaffWeglikowska Urszula,
Roth Siegmar
Publication year - 2010
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201000181
Subject(s) - raman spectroscopy , materials science , doping , surface modification , carbon nanotube , conductivity , exciton , scanning electron microscope , electrochemistry , analytical chemistry (journal) , nanotechnology , electrode , optoelectronics , chemistry , optics , condensed matter physics , composite material , physics , chromatography
We monitored the full sequence of electrochemical doping of a single‐walled carbon nanotube‐bundle sample (mean tube diameter 1.35 nm) in a NH 4 Cl solution from double‐layer charging to intercalation and functionalization with Raman spectroscopy, scanning electron microscopy, and transport measurements. The different doping dependences of the Raman intensity of metallic and semiconducting tubes are explained with the excitonic nature of the Raman effect in SWNTs. Temperature‐dependent conductivity measurements indicate a decreasing metallicity of the sample in the non‐covalent functionalization region where the conductivity still increases with doping level. We attribute this phenomenon to changes in the density of states of metallic SWNTs.