First Principle Study of Electron Transport in Single-Walled Carbon Nanotubes of 2 to 22 nm in Length

TL;DR

This study employs an ab initio elongation method to analyze electron transport in single-walled carbon nanotubes up to 22nm, revealing oscillating energy gaps and confirming ballistic transport properties at certain lengths.

Contribution

It introduces a novel elongation method based on density functional theory for studying large-scale SWCNTs at an all-electron level.

Findings

Oscillating energy gap behavior with nanotube length

Excellent agreement of I-V characteristics with experiments

Confirmation of ballistic transport in 15nm SWCNTs

Abstract

An elongation method based on ab initio quantum chemistry approaches is presented. It allows to study electronic structures and coherent electron transportation properties of single-walled carbon nanotubes (SWCNTs) up to 22nm in length using the hybrid density functional theory. The 22nm long SWCNT, consisting of more than ten thousands electrons, is the largest carbon nanotube that has ever been studied at such a sophisticated all-electron level. Interesting oscillating behaviour of the energy gap with respect to the length of the nanotube is revealed. The calculated current-voltage characteristics of SWCNTs are in excellent agreement with recent experimental results. It confirms the experimental observation that a 15nm long SWCNT is still largely a ballistic transport device. The proposed elongation method opens up a new door for the first principle study of nano- and bio-electronics.