First Principles Study of Work Functions of Double Wall Carbon Nanotubes

TL;DR

This study uses first-principles calculations to analyze how the work functions of double-walled carbon nanotubes vary with diameter, revealing significant differences from single-walled nanotubes and implications for nanoelectronic devices.

Contribution

It provides the first detailed analysis of work function variations in double-walled nanotubes using density functional theory and a charge equilibration model.

Findings

Work function varies up to 0.5 eV within 1-1.5 nm diameter range.

Significant work function change contrasts with single-walled nanotubes.

Charge redistribution explains work function variation.

Abstract

Using first-principles density functional calculations, we investigated work functions (WFs) of thin double-walled nanotubes (DWNTs) with outer tube diameters ranging from 1nm to 1.5nm. The results indicate that work function change within this diameter range can be up to 0.5 eV, even for DWNTs with same outer diameter. This is in contrast with single-walled nanotubes (SWNTs) which show negligible WF change for diameters larger than 1nm. We explain the WF change and related charge redistribution in DWNTs using charge equilibration model (CEM). The predicted work function variation of DWNTs indicates a potential difficulty in their nanoelectronic device applications.