Hall effect and magnetoresistance of carbon nanotube films

We report Hall coefficient (RH ) and magnetoresistance ({Δ}{ρ}/{ρ}) measurements on thin films of aligned carbon nanotubes. RH is positive in the whole temperature range (1.7--300 K) showing the predominance of hole transport in the electronic conduction. The upper limit of the carrier concentration is 1.6×{}10¹⁹ cm^-3 . The resistance of the thin-film samples is governed mainly by the loose tube-tube contacts and this shows up in the {Δ}{ρ}/{ρ}0 at low fields, suggesting a noncoherent transport between the nanotubes.