Domain formation on oxidized graphene

TL;DR

This study uses first-principles calculations to analyze how oxygen atoms adsorb on graphene, forming domain structures, affecting electronic properties, and resisting desorption without external influence.

Contribution

It reveals the domain formation mechanism of oxygen on graphene and its impact on electronic properties using first-principles and molecular dynamics calculations.

Findings

Oxygen adsorption causes charge transfer and domain formation.

Adsorption pattern influences band gap widening.

Oxygen adatoms are resistant to desorption without external agents.

Abstract

Using first-principles calculations within density functional theory we demonstrate that the adsorption of single oxygen atom results in significant electron transfer from graphene to oxygen. This strongly disturbs the charge landscape of the C-C bonds at the proximity. Additional oxygen atoms adsorbing to graphene prefer always the C-C bonds having highest charge density and consequently they have tendency to form domain structure. While oxygen adsorption to one side of graphene ends with significant buckling, the adsorption to both sides with similar domain pattern is favored. The binding energy displays an oscillatory variation and the band gap widens with increasing oxygen coverage. While a single oxygen atom migrates over the C-C bonds on graphene surface, a repulsive interaction prevents two oxygen adatoms from forming an oxygen molecule. Our first-principles study together with finite temperature ab-initio molecular dynamics calculations concludes that oxygen adatoms on graphene cannot desorb easily without influence of external agents.