Berlin 2018 – scientific programme

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O: Fachverband Oberflächenphysik

O 47: Poster: Graphene - Electronic Properties, Structure, Adsorption, Intercalation and Doping (joint session O/TT)

O 47.9: Poster

Tuesday, March 13, 2018, 18:15–20:30, Poster A

Microscopic investigations of graphene-nickel interactions — •Philip Schädlich, Florian Speck, Adrian Schütze, and Thomas Seyller — Professur für Technische Physik, TU Chemnitz, Reichenhainer Straße 70, D-09126 Chemnitz

In order to realize possible applications of graphene in electronics, it is important to understand the properties of graphene - metal contact interfaces. In this study we investigate the impact of nickel as possible contact material on the underlying graphene.

Graphene samples are grown by sublimation of Si atoms from a 6H-SiC(0001) substrate in Ar atmosphere at ambient pressure [1]. The local graphene coverage is probed by photoemission electron microscopy as well as low-energy electron microscopy (LEEM) and reflectivity (LEER) spectra. The deposition process of nickel is monitored in-situ via LEEM. After deposition, LEER spectra indicate a change of the work function in the covered areas while the characteristic interlayer states [2] stay unchanged. The morphology of the deposited nickel layer is revealed by atomic force microscopy, while the thickness was determined by x-ray photoemission spectroscopy. Angle-resolved photoemission spectroscopy confirms an unchanged electronic band structure with the Dirac point located 0.4 eV below the Fermi energy, which is close to values found for bare monolayer graphene on the 6H-SiC(0001) surface.

[1] K. V. Emtsev et al., Nature Materials 8, 203 (2009).

[2] N. Srivastava et al. Phys. Rev. B 87, 245414 (2013).