Carrier velocity in carbon nano tube field effect transistor

Abstract

The fact that there are no dangling bond states at the surface of CNT allows for a wide choice of gate insulators. There fore the CNT are being considered as viable candidates for high-speed applications. The mobility and saturation velocity are the two important parameters that control the charge transport in a conducting MOSFET channel. It is shown that the high mobility does not always lead to higher carrier velocity. The ultimate drift velocity in carbon nanotube due to the high electric-field streaming are based on the asymmetrical distribution function that converts randomness in zero-field to streamlined one in a very high electric field. The limitation drift velocity is found to be appropriate thermal velocity for non-degenerate regime, increasing with the temperature, but independent of carrier concentration. However, the limitation drift velocity is the Fermi velocity for degenerate regime increasing with carrier concentration but independent of the temperature.