Near-edge x-ray absorption fine structure investigation of graphene

TL;DR

This study uses near-edge x-ray absorption spectroscopy to analyze the electronic structure of graphene layers, revealing layer-dependent spectral features and confirming theoretical predictions about interlayer states.

Contribution

First detailed NEXAFS spectra of single-layer graphene obtained via PEEM, showing layer-dependent electronic structure changes and interlayer state signatures.

Findings

Observation of pi* resonance splitting in single-layer graphene

Detection of the predicted interlayer state

Rapid evolution of electronic structure with increasing layers

Abstract

We report the near-edge x-ray absorption fine structure (NEXAFS) spectrum of a single layer of graphite (graphene) obtained by micromechanical cleavage of Highly Ordered Pyrolytic Graphite (HOPG) on a SiO2 substrate. We utilized a PhotoEmission Electron Microscope (PEEM) to separately study single- double- and few-layers graphene (FLG) samples. In single-layer graphene we observe a splitting of the pi* resonance and a clear signature of the predicted interlayer state. The NEXAFS data illustrate the rapid evolution of the electronic structure with the increased number of layers.