Interaction of solid organic acids with carbon nanotube field effect transistors

TL;DR

This study investigates how different solid organic acids interact with carbon nanotube FETs, revealing that acid strength and type influence doping effectiveness, device threshold shifts, and hysteresis reduction, with implications for device fabrication.

Contribution

It demonstrates that solid organic acids can effectively p-dope carbon nanotube FETs, with doping efficiency depending on acid pKa and type, and that in-solution doping is compatible with standard fabrication processes.

Findings

Highly fluorinated acids effectively shift threshold voltage.

Doping reduces hysteresis in transfer characteristics.

In-solution doping maintains good transport properties.

Abstract

A series of solid organic acids were used to p-dope carbon nanotubes. The extent of doping is shown to be dependent on the pKa value of the acids. Highly fluorinated carboxylic acids and sulfonic acids are very effective in shifting the threshold voltage and making carbon nanotube field effect transistors to be more p-type devices. Weaker acids like phosphonic or hydroxamic acids had less effect. The doping of the devices was accompanied by a reduction of the hysteresis in the transfer characteristics. In-solution doping survives standard fabrication processes and renders p-doped carbon nanotube field effect transistors with good transport characteristics.