Field emission mechanisms of graphitic nanostructures

TL;DR

This study uses first-principles calculations to explore how hydrogen termination, electric field direction, and vacancy defects influence the field emission properties of graphitic nanostructures, revealing the role of dangling bonds in emission behavior.

Contribution

It provides a detailed theoretical analysis of the electronic states and emission mechanisms in graphitic nanostructures, highlighting the impact of structural modifications on FE performance.

Findings

FE current varies with hydrogen termination and electric field direction

Vacancy defects significantly enhance FE current in graphene sheets

Dangling-bond character governs the FE behavior of graphitic nanostructures

Abstract

Field emission (FE) and the electronic-states origin of graphitic nanostructures were investigated by first-principles calculations based on time-dependent density-functional theory. We find that the FE current from graphitic ribbons changes remarkably depending on the hydrogen termination and the direction of the applied electric field. Also, the FE current from graphene sheets shows a dramatic increase around vacancy defects. We verified, through the analysis of local electronic structures and energy distributions of emitted electrons, that the dangling-bond (or $\sigma$) character is responsible for these results and governs the nature of the FE of graphitic nanostructures.