Phonon-limited carrier mobility and resistivity from carbon nanotubes to graphene

TL;DR

This study uses atomistic calculations to compare phonon-limited electrical mobility in graphene and carbon nanotubes, revealing convergence of mobility values as nanotube diameter increases, especially at high temperature and carrier density.

Contribution

It provides a detailed theoretical analysis of the transition from 1D to 2D transport properties in carbon nanotubes and graphene, highlighting the conditions for their electrical properties to become similar.

Findings

Mobility in CNTs converges to graphene's mobility with increasing diameter.

High temperature and carrier density accelerate the convergence.

Small-diameter CNTs show strong dependence on chirality, diameter, and bandgap.

Abstract

Under which conditions do the electrical transport properties of one-dimensional (1D) carbon nanotubes (CNTs) and 2D graphene become equivalent? We have performed atomistic calculations of the phonon-limited electrical mobility in graphene and in a wide range of CNTs of different types to address this issue. The theoretical study is based on a tight-binding method and a force-constant model from which all possible electron-phonon couplings are computed. The electrical resistivity of graphene is found in very good agreement with experiments performed at high carrier density. A common methodology is applied to study the transition from 1D to 2D by considering CNTs with diameter up to 16 nm. It is found that the mobility in CNTs of increasing diameter converges to the same value, the mobility in graphene. This convergence is much faster at high temperature and high carrier density. For small-diameter CNTs, the mobility strongly depends on chirality, diameter, and existence of a bandgap.