Modelling of epitaxial graphene functionalization

TL;DR

This paper introduces a new model for epitaxial graphene on silicon carbide and uses density functional theory to study how different functional groups interact with it, revealing cluster formation tendencies and effects on electronic properties.

Contribution

It presents a novel model for epitaxial graphene and provides detailed DFT analysis of its functionalization with various chemical groups, highlighting differences in clustering and electronic effects.

Findings

Hydrogen and fluorine tend to form clusters at high concentrations.

Fluorine clustering induces midgap states due to graphene distortion.

Larger groups like methyl and phenyl prevent clustering, leading to uniform coverage and bandgap opening.

Abstract

A new model for graphene, epitaxially grown on silicon carbide is proposed. Density functional theory modelling of epitaxial graphene functionalization by hydrogen, fluorine and phenyl groups has been performed with hydrogen and fluorine showing a high probability of cluster formation in high adatom concentration. It has also been shown that the clusterization of fluorine adatoms provides midgap states in formation due to significant flat distortion of graphene. The functionalization of epitaxial graphene using larger species (methyl and phenyl groups) renders cluster formation impossible, due to the steric effect and results in uniform coverage with the energy gap opening.