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Exploring the possibilities of graphene functionalization using the physi-, chimi-sorption of molecules and metal intercalation - Laurent Simon

Institut de science des Matériaux de Mulhouse

Au Parc-Club - bât 23/25 - Orsay - Salle 215 - 1er étage

We have explored different possibilities to functionalize graphene. By working essentially with epitaxial graphene on SiC(0001) substrates, three approaches have been studied : The organization of self-assembled molecules with (1) the study of the molecule-graphene interaction, (2) the research of new strategies and molecular design to improve the reactivity of graphene in order to create chemical bonds with the possibility to control the reactive site, (3) the functionalization of graphene by the intercalation of metal atoms. In this talk we will focus on the covalent grafting of a new class of molecules for which a Diels Alder reaction was expected (fluorinated maleimide) and the intercalation of metal atoms.

We have combined the scanning probe microscopy techniques STM, STS and Fourier transform scanning tunneling spectroscopy, and more global electronic spectroscopic techniques such as the X-ray photo-emission and ARPES.

For the covalent grafting, we present a direct visualization of a cycloaddition reaction performed for some specific fluorinated maleimide molecules deposited on graphene. In the course of covalently grafting the molecules to graphene, the sp2 conjugation of carbon atoms was broken and local sp3 bonds were created. The grafted molecules perturbed the graphene lattice, generating a standing-wave pattern evidenced by STM, with an anisotropy, which was attributed to a (1,2) cycloaddition. ARPES measurements indicate a modification of the Fermi velocity and an opening of an electronic gap in graphene.
In the second part of this talk, we will show how it is possible to modify the electronic band structure of graphene by the intercalation of metal atoms (Au, Tb) between the graphene layer and the substrate. These studies have shown the possibility to modify the graphene band structure : the modification of the Fermi level position, and strong renormalization effect near Dirac point or the Fermi level in the case of heavily n-doped graphene.

L. Daukiya et al arXiv:1604.03125 (submitted)


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