Effect of Oxygen Adsorption on the Local Properties of Epitaxial Graphene on SiC (0001)

TL;DR

This study investigates how oxygen adsorption modifies the local structure and electronic properties of epitaxial graphene on SiC(0001), revealing partial decoupling of the buffer layer and tunable charge density through controlled oxidation.

Contribution

It demonstrates that oxygen intercalation can decouple the buffer layer and modulate charge density in epitaxial graphene on SiC(0001).

Findings

Oxygen saturates Si dangling bonds and breaks Si-C bonds.

Partial decoupling of the buffer layer occurs after oxidation.

Charge density in graphene can be tuned via oxidation parameters.

Abstract

The effect of oxygen adsorption on the local structure and electronic properties of monolayer graphene grown on SiC(0001) has been studied by means of Low Energy Electron Microscopy (LEEM), microprobe Low Energy Electron Diffraction (\muLEED) and microprobe Angle Resolved Photoemission (\muARPES). We show that the buffer layer of epitaxial graphene on SiC(0001) is partially decoupled after oxidation. The monitoring of the oxidation process demonstrates that the oxygen saturates the Si dangling bonds, breaks some Si-C bonds at the interface and intercalates the graphene layer. Accurate control over the oxidation parameters enables us to tune the charge density modulation in the layer.