Self-aligned carbon nanotube transistors with charge transfer doping

This letter reports a charge transfer p -doping scheme which utilizes one-electron oxidizing molecules to obtain stable, unipolar carbon nanotube transistors with a self-aligned gate structure. This doping scheme allows one to improve carrier injection, tune the threshold voltage Vth, and enhance the device performance in both the "ON-" and "OFF-" transistor states. Specifically, the nanotube transistor is converted from ambipolar to unipolar, the device drive current is increased by 2-3 orders of magnitude, the device OFF current is suppressed and an excellent Ion Ioff ratio of 106 is obtained. The important role played by metal-nanotube contacts modification through charge transfer is demonstrated. © 2005 American Institute of Physics.