High-field Current-carrying Capacity of Semiconducting Carbon Nanotubes

TL;DR

This paper demonstrates that semiconducting carbon nanotubes exhibit current saturation behavior similar to metallic ones at high carrier densities, influenced by band structure and phonon interactions, with implications for nanoelectronic device performance.

Contribution

It reveals that current saturation in semiconducting nanotubes is governed by carrier density and bandgap effects, providing a unified understanding of their high-field transport properties.

Findings

Current saturation in semiconducting nanotubes matches metallic behavior above a critical carrier density.

Saturation velocity at high fields depends on carrier density but not on bandgap.

The results explain recent experimental observations of high-field transport in nanotubes.

Abstract

It is shown that current saturation in semiconducting carbon nanotubes is indistinguishable from metallic nanotubes if the carrier density is above a critical value determined by the bandgap and the LO phonon energy. This feature stems from the higher number of current-carrying states in the semiconducting tubes due to the van-Hove singularity at the band-edge. Above this critical carrier density, the ensemble saturation velocity at high-fields is found to be independent of the bandgap, but strongly dependent on the carrier density, explaining recent observations.