Electrical characteristics of CNFETs with asymmetric gating structures

We demonstrated a straightforward technique, including device structures and associated fabrication processes to produce carbon nanotube field-effect transistors (CNFETs) which have different gate oxide thickness at two terminal junctions. Since a thinner oxide layer induces stronger gate field at one junction terminal than a thicker one, robust unipolar CNFETs were carried out. The blockage of one type of carriers is due to a Schottky barrier at the terminal junction with the thicker bottom oxide. The high ON/OFF ratios, up to 104, in such asymmetric gating devices show that the gate field is equally effective as the devices with uniformly thin oxide layer, and the ensuring unipolar behavior is much feasible toward nanotubes based electronics.