Visualizing Individual Nitrogen Dopants in Monolayer Graphene

TL;DR

This paper combines experimental and computational techniques to visualize and analyze individual nitrogen dopants in monolayer graphene, revealing their local electronic effects and potential for tuning graphene's properties.

Contribution

It provides the first detailed visualization and characterization of single nitrogen dopants in graphene using multiple methods, highlighting their electronic influence.

Findings

Nitrogen atoms are incorporated as graphitic dopants.

A fraction of the extra electron delocalizes into the lattice.

Electronic modifications are localized within a few lattice spacings.

Abstract

In monolayer graphene, substitutional doping during growth can be used to alter its electronic properties. We used scanning tunneling microscopy (STM), Raman spectroscopy, x-ray spectroscopy, and first principles calculations to characterize individual nitrogen dopants in monolayer graphene grown on a copper substrate. Individual nitrogen atoms were incorporated as graphitic dopants, and a fraction of the extra electron on each nitrogen atom was delocalized into the graphene lattice. The electronic structure of nitrogen-doped graphene was strongly modified only within a few lattice spacings of the site of the nitrogen dopant. These findings show that chemical doping is a promising route to achieving high-quality graphene films with a large carrier concentration.