Atomic-scale characterization of nitrogen-doped graphite: Effects of dopant nitrogen on the local electronic structure of the surrounding carbon atoms

TL;DR

This study investigates the atomic and electronic effects of nitrogen doping in graphite, revealing how different nitrogen species influence local electronic states near the Fermi level through combined experimental and theoretical approaches.

Contribution

It provides a detailed atomic-level characterization of nitrogen-doped graphite, identifying specific nitrogen species and their impact on local electronic structures using advanced microscopy, spectroscopy, and calculations.

Findings

Identification of pyridinic-N and graphitic-N at atomic level.

Localized electronic states near the Fermi level around nitrogen sites.

Correlation between nitrogen species and electronic structure modifications.

Abstract

We report the local atomic and electronic structure of a nitrogen-doped graphite surface by scanning tunnelling microscopy, scanning tunnelling spectroscopy, X-ray photoelectron spectroscopy, and first-principles calculations. The nitrogen-doped graphite was prepared by nitrogen ion bombardment followed by thermal annealing. Two types of nitrogen species were identified at the atomic level: pyridinic-N (N bonded to two C nearest neighbours) and graphitic-N (N bonded to three C nearest neighbours). Distinct electronic states of localized {\pi} states were found to appear in the occupied and unoccupied regions near the Fermi level at the carbon atoms around pyridinic-N and graphitic-N species, respectively. The origin of these states is discussed based on the experimental results and theoretical simulations.