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Charge transport in surfactant‐free single walled carbon nanotube networks
Author(s) -
Ravi Shrividya,
Kaiser Alan B.,
Bumby Christopher W.
Publication year - 2013
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.201300033
Subject(s) - carbon nanotube , materials science , variable range hopping , conductivity , thermal conduction , conductance , metal , schottky diode , schottky barrier , electrical resistivity and conductivity , condensed matter physics , chemical physics , nanotechnology , optoelectronics , composite material , chemistry , electrical engineering , physics , engineering , diode , metallurgy
Conduction in thin random networks of single‐walled carbon nanotubes (SWNTs) is typically dominated by metallic SWNT segments and limited by variable‐range hopping (VRH) in disordered junction regions. However, in our surfactant‐free networks, we show that in parallel with VRH there is another mode of conduction involving both semiconducting and metallic SWNTs. This second process showing activated behavior makes a substantial contribution to conductance at higher temperatures, with similar activation energies in different samples despite a large variation in overall magnitude of the conductivity. From the magnitude of the activation energy (0.16 0.05\,eV), we ascribe this additional term to activation across Schottky barriers between metallic and semiconducting SWNTs in conducting paths involving a small number of semiconducting SWNTs. The Mott parameters for VRH are also independent of the overall conductivity, indicating that the local structure of intertube contacts between metallic SWNTs in the most conductive paths is also similar in samples of different overall conductivity.