Switching behavior of semiconducting carbon nanotubes under an external electric field

We investigate theoretically the switching characteristics of semiconductin g carbon nanotubes connected to gold electrodes under an external (gate) el ectric field. We find that the external introduction of holes is necessary to account for the experimental observations. We identify metal-induced gap states (MIGS) at the contacts and find that the MIGS of an undoped tube wo uld not significantly affect the switching behavior, even for very short tu be lengths. We also explore the miniaturization limits of nanotube transist ors, and, on the basis of their switching ratio, we conclude that transisto rs with channels as short as 50 Angstrom would have adequate switching char acteristics. (C) 2001 American Institute of Physics.