Avalanche-Induced Current Enhancement in Semiconducting Carbon Nanotubes

TL;DR

This paper investigates how high electric fields cause avalanche-induced current enhancement in semiconducting carbon nanotubes, revealing a diameter-dependent process involving multi-band transport and providing a new method to measure phonon emission length.

Contribution

It introduces a novel understanding of avalanche processes in 1D quantum wires and presents a method to determine the inelastic optical phonon emission length from experimental data.

Findings

Current increases exponentially at high electric fields due to avalanche effects.

Avalanche process involves access to the third sub-band in nanotubes.

The phonon emission length scales with diameter as ~15d nm.

Abstract

Semiconducting carbon nanotubes under high electric field stress (~10 V/um) display a striking, exponential current increase due to avalanche generation of free electrons and holes. Unlike in other materials, the avalanche process in such 1D quantum wires involves access to the third sub-band, is insensitive to temperature, but strongly dependent on diameter ~exp(-1/d^2). Comparison with a theoretical model yields a novel approach to obtain the inelastic optical phonon emission length, L_OP,ems ~ 15d nm. The combined results underscore the importance of multi-band transport in 1D molecular wires.