Quasi freestanding two-dimensional conductor with massless charge carriers

(PhysOrg.com) -- Graphene - a single layer of carbon atoms arranged in a honeycomb lattice - is one of the paradigm two-dimensional systems existing today.

Although ideal free-standing two-dimensional crystals were believed to be unstable, Novoselov et al. succeeded in preparing small flakes of single layer graphene in 2004.

Since then graphene has been renowned for its extraordinary crystalline quality, its extremely high carrier mobility, as well as for its peculiar charge carriers that behave like massless particles.

Today, graphene is among those few materials that might present an alternative to standard silicon-based electronics. In order to achieve this ambitious goal a number of obstacles have to be overcome.

One major challenge is the large scale production of high-quality graphene.

Berger et al. have shown that graphene can be grown on wafer size scale by thermal decomposition of silicon carbide.

However, graphene grown on the Si-terminated face of SiC is affected considerably by the underlying substrate resulting in e.g. reduced charge carrier mobility. We have succeeded in intercalating gold atoms between the first carbon monolayer and the silicon carbide substrate.

Thereby, the graphene-to-substrate distance is increased and the graphene layer is electronically decoupled from the substrate, approaching the promising electronic properties of quasi-freestanding graphene.

See the related publication at: prb.aps.org/abstract/PRB/v81/i23/e235408

Provided by University of Wisconsin-Madison