Low-frequency noise in top-gated ambipolar carbon nanotube field effect transistors

Low-frequency noise of top-gated ambipolar carbon nanotube field effect transistors (CNT-FETs) with aligned CNT growth onto the quartz substrate is presented. The noise of top-gated CNT-FETs in air is lower than that of back-gated devices, and is comparable to that of back-gated devices in vacuum. It shows that molecules in air act as additional scattering sources, which contribute to the noise. Different noise amplitudes in the electron-conduction and the hole-conduction regions are due to different Schottky barriers with respect to the conduction and valance bands as well as the scattering in the channel. (C) 2008 American Institute of Physics.