Thin graphite overlayers: Graphene and alkali metal intercalation
Artikel i vetenskaplig tidskrift, 2007

Using LEED and angle resolved photoemission for characterisation we have prepared graphite overlayers with down to monolayer thickness by heating SiC crystals and monitored alkali metal intercalation for the multilayer films. The valence band structure of the monolayer is similar to that calculated for graphene though downshifted by around 0.8 eV and with a small gap at the zone corner. The shift suggests that the transport properties, which are of much present interest, are similar to that of a biased graphene sample. Upon alkali metal deposition the 3D character of the pi states is lost and the resulting band structure becomes graphene like. A comparison with data obtained for ex situ prepared intercalation compounds indicates that the graphite film has converted to the stage I compounds C8K or CgRb. Advantages with the present preparation method is that the graphite film can be recovered by desorbing small amounts of alkali metal and that the progress of compound formation can be monitored. The energy shifts measured after different deposits indicate that saturation is reached in three steps. Our interpretation is that in the first the alkali atoms are dispersed while the final steps are characterized by the formation of first one and then a second (2 x 2) ordered alkali metal layer adjacent to the uppermost carbon layer. (c) Elsevier B.V. All rights reserved.

graphene

alkali metal

CHARGE-TRANSFER

ULTRAVIOLET PHOTOELECTRON-SPECTROSCOPY

C8K

angle resolved photoemission

silicon carbide

SUBMONOLAYER POTASSIUM

SCANNING-TUNNELING-MICROSCOPY

ELECTRONIC BAND-STRUCTURE

SINGLE-CRYSTAL GRAPHITE

graphite

ANGLE-RESOLVED PHOTOEMISSION

intercalation

SYNCHROTRON-RADIATION

SURFACE

Författare

Jonathan Anderson

Chalmers, Teknisk fysik, Fasta tillståndets fysik

T. Balasubramanian

Lunds universitet

Marcus Breitholtz

Chalmers, Teknisk fysik, Fasta tillståndets fysik

Theresa Kihlgren

Chalmers University of Technology

Lars Erik Gustaf Wallden

Chalmers, Teknisk fysik

Surface Science

0039-6028 (ISSN)

Vol. 601 1167-1175

Ämneskategorier

Annan teknik

DOI

10.1016/j.susc.2006.12.039