Dresden 2014 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 121: Graphene (organized by DS)
HL 121.5: Talk
Friday, April 4, 2014, 12:30–12:45, CHE 89
Graphene functionalisation with N and O: reversible or permanent modification of the electronic properties? — •Peter Brommer1,2, Alex Marsden1, Neil Wilson1, Gavin Bell1, and David Quigley1,2 — 1Department of Physics, University of Warwick, Coventry, UK — 2Centre for Scientific Computing, University of Warwick, Coventry, UK
For many applications it is essential to modify the electronic properties of graphene in a controlled fashion. This can be achieved via oxygen and nitrogen functionalisation in ultra-high vacuum, leading to a system in which electronic and structural properties can be systematically studied. Low dose oxygen functionalisation (< 5 atomic percent) can be reversed completely by annealing at 200 ∘C, while nitrogen permanently integrates itself into the material. Here we present insights from DFT calculations on this system, such as the low-energy configurations and simulated transmission electron microscopy (TEM) images, binding energies and effective band structures of the N and O decorated graphene sheets. We directly compare our results with experiments on CVD grown graphene. Angle-resolved photoemission spectroscopy (ARPES) resolves the band structure changes on functionalization, whilst X-ray photoelectron spectroscopy (XPS) provides information about the chemical environment of the defect atoms. Combined, the computational and experimental data can offer insights into the structural changes induced by the functionalisation process and their consequences on the electronic properties of the material.