Electrical Nanoprobing of Semiconducting Carbon Nanotubes using an Atomic Force Microscope

TL;DR

This paper demonstrates the use of an Atomic Force Microscope tip as a nanoscale probe to locally measure and analyze the electronic properties of semiconducting carbon nanotube transistors, revealing contact behaviors and device scaling.

Contribution

It introduces a novel method of using AFM tips as movable voltage and current probes for detailed nanoscale electrical characterization of carbon nanotubes.

Findings

Gold contacts form no Schottky barrier in p-region

Large contact resistance in n-region dominates transport

Device properties scale with channel length

Abstract

We use an Atomic Force Microscope (AFM) tip to locally probe the electronic properties of semiconducting carbon nanotube transistors. A gold-coated AFM tip serves as a voltage or current probe in three-probe measurement setup. Using the tip as a movable current probe, we investigate the scaling of the device properties with channel length. Using the tip as a voltage probe, we study the properties of the contacts. We find that Au makes an excellent contact in the p-region, with no Schottky barrier. In the n-region large contact resistances were found which dominate the transport properties.