Determination of the small band gap of carbon nanotubes using the ambipolar random telegraph signal.

The ambipolar random telegraph signal (RTS) (i.e., RTS in both hole conduction at negative gate biases and electron conduction at positive gate biases) is observed in an ambipolar carbon nanotube field-effect transistor (CNT-FET). Then, the ambipolar RTS is used to extract the small band gap of the SWNT. The determination of the small band gap CNT using RTS demonstrates a potentially high accuracy and stability. Other methods are provided to confirm the small band gap of the SWNT.