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HL: Fachverband Halbleiterphysik

HL 44: Poster Session I

HL 44.11: Poster

Dienstag, 15. März 2011, 18:00–21:00, P3

Magnetotransport Studies of Graphene on GaAs — •Nils Gayer, Karen Peters, Alina Tittel, Andreas Graf, Vera Paulava, Ursula Wurstbauer, and Wolfgang Hansen — Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Germany

We study graphene on GaAs substrates, the preferred material for ultrafast and optical device applications. With temperature dependent magnetotransport measurements the influence of the GaAs substrates on the properties of graphene is investigated. Our substrates contain a Si-doped GaAs backgate grown by means of molecular beam epitaxy. The investigated graphene flakes were prepared by mechanical cleavage of natural graphite. Due to the very low contrast of graphene on GaAs, we established a method to enhance the visibility of graphene that facilitates the detection of graphene on this substrate using optical microscopy. For this purpose, the prepared graphene samples are spin-coated with PMMA e-beam resists of optimized layer thickness. We demonstrate that it is possible to determine the number of layers of graphene on GaAs even through the PMMA resist layer using Raman spectroscopy. We discuss our findings as well as according calculations of the contrast of graphene on GaAs as a function of the wavelength of the incident light and the PMMA layer thickness.