Ambipolar Electrical Transport in Semiconducting Single-Wall Carbon Nanotubes

Ambipolar electrical transport is reported in single-wall carbon nanotube (SWNT) field-effect transistors. In particular, the properties of SWNT junctions to TiC are discussed in detail. The carbide-nanotube junctions are abrupt and robust. In contrast to planar junctions, these contacts present low resistance for the injection of both $p$- and $n$-type carriers—the apparent barrier height of the junction is modified by the gate field. Thus SWNTs offer the novel possibility of ambipolar Ohmic contacts.