Advances in carbon nanotube electronics

State-of-the-art carbon nanotube field-effect transistors (CNFETs) behave as Schottky barrier (SB)-modulated transistors. In order to address the disadvantages of a SB-CNFET, e.g. drain-dependent OFF states, ambipolar behaviors, and a large inverse subthershold slope, two improved CNFET structures are studied here. Through gate structure engineering, we have fabricated high-performance, enhancement-mode CNFETs exhibiting n or p-type unipolar behavior, tunable by electrostatic and/or chemical doping, with excellent OFF-state performance and a steep subthreshold swing (S = 63 mV/dec).