Tunable ambipolar Coulomb blockade characteristics in carbon nanotubes-gated carbon nanotube field-effect transistors

Abstract

A single-walled carbon nanotube field-effect transistor has been fabricated with two single-walled carbon nanotube bundles as its top gates and a heavily doped p-type silicon substrate as its global back gate. The channel conductance is found to oscillate significantly as a function of the top- and back-gate voltages when the device is measured at 100 K or below. “Diamond”-shaped current forbidden regions can be clearly observed under both positive and negative top-gate voltages. A single-electron transistor model is proposed to qualitatively explain the observations.