First Principles Study of Work Functions of Single Wall Carbon Nanotubes

TL;DR

This study uses first principles calculations to analyze how the work functions of single wall carbon nanotubes vary with diameter and chirality, revealing distinct behaviors in different size classes.

Contribution

It provides a detailed first-principles analysis of work function variations in SWNTs based on diameter and chirality, highlighting the roles of surface dipoles and hybridization effects.

Findings

Work functions of larger SWNTs are narrowly distributed (~0.1 eV) and unaffected by chirality.

Smaller SWNTs show significant work function changes with diameter and chirality.

Surface dipoles and hybridization effects drive the observed work function variations.

Abstract

We performed first principles calculations on work functions of single wall carbon nanotubes (SWNTs), which can be divided into two classes according to tube diameter (D). For class I tubes (D > 1 nm), work functions lie within a narrow distribution (~0.1 eV) and show no significant chirality or diameter dependence. For class II tubes (D < 1 nm), work functions show substantial changes, with armchair tubes decrease monotonously with diameter, while zigzag tubes show opposite trend. Surface dipoles and hybridization effects are shown to be responsible for the observed work function change.