  We present an atomistic self-consistent study of the electronic and transport
properties of semiconducting carbon nanotube in contact with metal electrodes
of different work functions, which shows simultaneous electron and hole doping
inside the nanotube junction through contact-induced charge transfer. We find
that the band lineup in the nanotube bulk region is determined by the effective
work function difference between the nanotube channel and source/drain
electrodes, while electron transmission through the SWNT junction is affected
by the local band structure modulation at the two metal-nanotube interfaces,
leading to an effective decoupling of interface and bulk effects in electron
transport through nanotube junction devices.
