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The 15th International Conference on

Vibrations at Surfaces

June 22-26, 2015 ▪ Donostia-San Sebastián, Spain

Donostia Igeldotik

Program

OverviewMondayTuesdayWednesdayThursdayFriday

Tuesday June 23

09:00-10:40 Tu1: Transport in electronic devices
10:40-11:20 Coffee break
11:20-13:00 Tu2: Surface diffusion and migration
13:00-15:30 Lunch break (on your own)
15:30-16:40 Tu3: Chemistry and growth of graphene
16:40-17:20 Coffee break
17:20-18:50 Tu4: Electron-phonon coupling in graphene
19:00-21:30 Poster session A

Tu3: Chemistry and growth of graphene

Chair: H. Hedgeland, London, UK

15:30-16:00 M.-L. Bocquet, Paris, France
Cycloaddition of metal-supported graphene interfaces: a first principles investigation
16:00-16:20 A. I. Shkrebtii, Toronto, Canada
Vibrations, optics and bonding in graphene based heterosystems functionalised with hydrogen
16:20-16:40 D. Farías, Madrid, Spain
Helium diffraction from graphene grown by chemical vapor deposition on copper catalysts

Contributed talk

Helium diffraction from graphene grown by chemical vapor deposition on copper catalysts

A. Al Taleb1, H. Ki Yu2,3, G. Anemone1, A. M. Wodtke2,3, and D. Farías1,4,5

1Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Spain

2Institute for Physical Chemistry, University of Göttingen, 37077 Göttingen, Germany

3Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany

4Instituto "Nicolás Cabrera", Universidad Autónoma de Madrid, Spain

5Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Spain

In this work we use Helium atom scattering (HAS) as a sensitive probe of the crystallinity of graphene grown by chemical vapor deposition (CVD) on Cu, and as a probe of its interactions with its substrate. The high sensitivity of HAS to surface defects [1] precluded its use with current available graphene/Cu foils. Our current results have been obtained using graphene/Cu(111) grown on sapphire samples and graphene grown on a peeled-off epitaxial Cu(111) foil using a recently developed scheme [2]. We have measured the structure and the acoustic phonon modes of CVD graphene grown on these two samples. The observation of high reflectivities and clear diffraction peaks demonstrates the presence of high-quality graphene, with both long-range order and a very low density of defects over a surface area of the order of 1mm2. The shape of elastic and quasi-elastic scattering features proves that, surprisingly, graphene grown on a peeled-off epitaxial Cu(111) foil exhibits a much higher crystallinity than the one grown on Cu(111)/Al2O3 samples. The graphene lattice parameter was found to remain constant in the temperature range between 110-500 K, which proves that graphene is decoupled from the Cu substrate. A parabolic dispersion phonon branch has been measured along ΓM, as expected for the acoustic ZA mode in free-standing graphene.

[1] B. Poelsema and G. Comsa, Scattering of Thermal Energy Atoms from Disordered Surfaces. Springer Tracts in Modern Physics 115. Springer, Berlin, (1989)

[2] H. K. Yu, K. Balasubramanian, K. Kim, J.-L. Lee, M. Maiti, C. Ropers, J. Krieg, K. Kern, and A. M. Wodtke, ACS Nano 8, 8636 (2014)