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Local measurement of charge density in carbon nanotubes by Raman spectroscopy
Author(s) -
Freitag Marcus,
Tsang James,
Avouris Phaedon
Publication year - 2008
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.200879588
Subject(s) - raman spectroscopy , carbon nanotube , phonon , materials science , fermi level , density of states , condensed matter physics , doping , laser linewidth , spectroscopy , nanotube , electron , nanotechnology , optoelectronics , physics , optics , laser , quantum mechanics
The energies of the Raman G‐band transitions in both metallic and semiconducting CNTs are renormalized by the electron‐phonon interaction, leading to energy shifts in Raman spectra of gated CNT devices. In addition in metallic CNTs, the linewidth decreases sharply upon electrostatic doping because the Γ‐point phonon can no longer decay into electron‐hole pairs when the Fermi level is removed by more than 1/2 the phonon energy from the K‐point. Raman spectroscopy can therefore be used to locally measure charge density and capacitance of individual CNTs in a nanotube field‐effect transistor. Experiments under bias reveal breaks in nanotubes and depleted nanotube segments close to the contacts. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)