Electrostatic effects on contacts to carbon nanotube transistors

TL;DR

This paper uses numerical simulations to study how electrostatic effects at contacts influence the performance of carbon nanotube transistors, highlighting the importance of contact geometry and gate oxide thickness.

Contribution

It reveals how unscreened charge causes potential barriers at contacts, affecting device transport, and suggests ways to mitigate this through contact design and oxide thickness adjustments.

Findings

Unscreened charge creates potential barriers at contacts.

Barrier effects are most significant at intermediate gate voltages.

Reducing gate oxide thickness mitigates electrostatic barriers.

Abstract

We use numerical simulations to investigate the effect of electrostatics on the source and drain contacts of carbon nanotube field-effect transistors. We find that unscreened charge on the nanotube at the contact-channel interface leads to a potential barrier that can significantly hamper transport through the device. This effect is largest for intermediate gate voltages and for contacts near the ohmic-Schottky crossover, but can be mitigated with a reduction in the gate oxide thickness. These results help to elucidate the important role that contact geometry plays in the performance of carbon nanotube electronic devices.