Quasi-free Standing Epitaxial Graphene on SiC by Hydrogen Intercalation

TL;DR

This paper demonstrates a method to produce quasi-free standing epitaxial graphene on SiC by hydrogen intercalation, effectively decoupling the graphene layer from the substrate and preserving its electronic properties.

Contribution

It introduces a hydrogen intercalation technique to convert epitaxial graphene on SiC into quasi-free standing graphene with stable, reversible properties.

Findings

Hydrogen intercalation decouples graphene from SiC substrate.

The process is stable in air and reversible by annealing.

Resulting graphene exhibits typical linear pi-bands.

Abstract

Quasi-free standing epitaxial graphene is obtained on SiC(0001) by hydrogen intercalation. The hydrogen moves between the 6root3 reconstructed initial carbon layer and the SiC substrate. The topmost Si atoms which for epitaxial graphene are covalently bound to this buffer layer, are now saturated by hydrogen bonds. The buffer layer is turned into a quasi-free standing graphene monolayer with its typical linear pi-bands. Similarly, epitaxial monolayer graphene turns into a decoupled bilayer. The intercalation is stable in air and can be reversed by annealing to around 900 degrees Celsius.