Publication

Large Band Gap Opening between Graphene Dirac Cones Induced by Na Adsorption onto an Ir Superlattice

Harald Brune, Stefano Rusponi
2012
Journal Articles

Abstract

We investigate the effects of Na adsorption on the electronic structure of bare and Ir cluster superlattice-covered epitaxial graphene on Ir(111) using angleresolved photoemission spectroscopy and scanning tunneling microscopy. At Na saturation coverage, a massive charge migration from sodium atoms to graphene raises the graphene Fermi level by ∼1.4 eV relative to its neutrality point. We find that Na is adsorbed on top of the graphene layer, and when coadsorbed onto an Ir cluster superlattice, it results in the opening of a large band gap of ΔNa/Ir/G = 740 meV, comparable to the one of Ge and with preserved high group velocity of the charge carriers.

Official source

https://infoscience.epfl.ch/entities/publication/7bedc76f-203d-45b7-af99-3da6f8da941c

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Harald Brune, Stefano Rusponi
2012
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/7bedc76f-203d-45b7-af99-3da6f8da941c

About this result

Related concepts (31)

Graphene

Graphene (ˈgræfiːn) is an allotrope of carbon consisting of a single layer of atoms arranged in a hexagonal lattice nanostructure. The name is derived from "graphite" and the suffix -ene, reflecting the fact that the graphite allotrope of carbon contains numerous double bonds. Each atom in a graphene sheet is connected to its three nearest neighbors by σ-bonds and a delocalised π-bond, which contributes to a valence band that extends over the whole sheet.

Electronic band structure

In solid-state physics, the electronic band structure (or simply band structure) of a solid describes the range of energy levels that electrons may have within it, as well as the ranges of energy that they may not have (called band gaps or forbidden bands). Band theory derives these bands and band gaps by examining the allowed quantum mechanical wave functions for an electron in a large, periodic lattice of atoms or molecules.

Potential applications of graphene

Potential graphene applications include lightweight, thin, and flexible electric/photonics circuits, solar cells, and various medical, chemical and industrial processes enhanced or enabled by the use of new graphene materials. In 2008, graphene produced by exfoliation was one of the most expensive materials on Earth, with a sample the area of a cross section of a human hair costing more than

1,000 as of April 2008 (about

100,000,000/cm2). Since then, exfoliation procedures have been scaled up, and now companies sell graphene in large quantities.

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