Regensburg 2016 – scientific programme

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O: Fachverband Oberflächenphysik

O 45: Graphene: Adsorption, Intercalation and Doping

O 45.6: Poster

Tuesday, March 8, 2016, 18:15–20:30, Poster E

Near-Saturated Hydrogenation of Graphene on Ir(111) — •Clifford Murray, Ulrike Schröder, Antonio Martínez-Galera, and Thomas Michely — II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany

Hydrogen adsorption structures on graphene on Ir(111) have previously demonstrated their potential to modify the electronic properties of graphene (Gr) [1,2]. We have combined temperature programmed desorption (TPD) and scanning tunneling microscopy to further the understanding of this hydrogenation when close to saturation. We investigate dosage dependence of deuterium radical adsorption, diffusion thereof, and calculate coverages by calibrating TPD spectra. These spectra show two broad desorption peaks - at roughly 380K and 730K - representing two different adsorption states for deuterium on graphene. By growth of a Pt cluster superlattice we selectively block a specific area in the Gr moiré from adsorption. Subsequent radical exposure and the attenuation of the high temperature peak in desorption from this sample allows us to pin-point the binding area of the radicals. It is consistent with the formation of graphane-like patches in the moiré unit cell. We will speculate on the nature of the low temperature desorption peak.

[1] R. Balog et al., Nature Mater, 9, 315 (2010)

[2] R. Balog et al., ACS Nano, 7, 3823 (2013)