Lateral scaling in carbon nanotube field-effect transistors

TL;DR

This paper demonstrates that carbon nanotube FETs can operate via bulk switching rather than contact modulation, providing evidence for ballistic transport over hundreds of nanometers, which impacts future nanoelectronic device design.

Contribution

It introduces multi-gate CNFETs with independent gate control and reveals the transition from Schottky barrier to bulk switching, highlighting ballistic transport in semiconducting CNTs.

Findings

Device exhibits different characteristics depending on gate segment location.

Current is independent of gate length, indicating ballistic transport.

Evidence of bulk switching over hundreds of nanometers.

Abstract

We have fabricated carbon nanotube (CN) field-effect transistors with multiple, individually addressable gate segments. The devices exhibit markedly different transistor characteristics when switched using gate segments controlling the device interior versus those near the source and drain. We ascribe this difference to a change from Schottky barrier modulation at the contacts to bulk switching. We also find that the current through the bulk portion is independent of gate length for any gate voltage, offering direct evidence for ballistic transport in semiconducting CNs over at least a few hundred nanometers, even for relatively small carrier velocities.