posted 27 Jul 2015, 00:15 by info admin
Cassidy, Mikkel Kongsfelt, Jakob Jørgensen, Steen Pederson, Jan Knudsen, Kim Daasbjerg,
for Physics and Astronomy, Aarhus University
Creating sp3 defect sites in an otherwise perfect sp2 graphene lattice, in a controlled manner, has been shown to introduce a band gap in the electronic structure of graphene . Here, we exploit the Moire lattice which emerges following the epitaxial growth of graphene on an Ir(111) surface to create sp3 defect sites, in patterned formation, on the graphene basal plane. Significantly, these sp3 defects are created by attaching functional groups such as aryl rings to the graphene lattice. We have used a clean, surface science approach, under ultra-high vacuum conditions, to functionalize the graphene basal plane. This allows us to follow the progress of the reaction with cryo-scanning tunnelling microscopy, x-ray photoelectron spectroscopy and mass spectrometry. We deposit triazene moieties (1), to form a molecular monolayer on a graphene sheet prepared under ultra-high vacuum conditions. This layer is then heated to force a reaction with the under lying graphene (3). The results provide a detailed spatial and electronic profile of the chemically functionalised graphene sheet. X-ray photoemission spectroscopy confirms that new bonds are formed while scanning tunnelling microscopy data shows that new bonds are selectively formed at preferred sites on the Moire pattern.
1. R. Balog et al., Nat Mat., 2010, 9, pp. 315-319
Andrew Cassidy is a post doc at the Institute
for Physics and Astronomy at Aarhus University. He is primarily interested in
the chemical interactions between a surface and its environment, and in
particular the chemistry of graphene on various substrates. He received his
B.Sc. in Chemistry from University College Dublin (2006) and a Ph.D. in
Chemistry (2010) from the University of Cambridge where he studied the
interfacial chemistry of organic crystal surfaces. Since finishing his Ph.D, he
has been a postdoctoral researcher in Aarhus, working with Prof. David Field
and Assoc. Prof.