Self-aligned carbon nanotube transistors with charge transfer doping

TL;DR

This paper introduces a charge transfer doping method for carbon nanotube transistors that achieves stable, unipolar operation, significantly improves performance, and demonstrates the importance of contact modification.

Contribution

It presents a novel charge transfer doping scheme enabling self-aligned, unipolar carbon nanotube transistors with enhanced performance and controlled threshold voltage.

Findings

Device drive current increased by 2-3 orders of magnitude

Achieved an Ion/Ioff ratio of six orders of magnitude

Converted ambipolar transistors to unipolar with improved stability

Abstract

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 six order of magnitude is obtained. The important role played by metal-nanotube contacts modification through charge transfer is demonstrated.