Regensburg 2010 – scientific programme

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O: Fachverband Oberflächenphysik

O 43: Graphene I

O 43.7: Talk

Wednesday, March 24, 2010, 12:00–12:15, H31

Optical detection of single graphenes on mica with a contrast as high as 14% — •Martin Dorn, Phillipp Lange, Alexei Chekushin, Nicolai Severin, and Jürgen Rabe — Humboldt-Universität zu Berlin, Department of Physics, Newtonstr. 15, 12489 Berlin, Germany

Graphene is a one atom thick material with unique properties arising from its two dimensional crystal lattice. Most of graphene devices are fabricated on silicon wafers covered with a SiO2 layer necessary for optical detection of single graphenes. Graphene adhering to a SiO2 layer follows the intrinsic roughness of the latter and therefore cannot be considered strictly two dimensional. Mica is a natural crystal with perfect atomically flat cleavage planes. We demonstrate here a simple optical microscopy method for the detection of graphenes on mica with up to 14% of single graphene optical contrast. The experimental results are rationalized with a Fresnel-law based model. The contrast is only weakly wavelength dependent, i.e. white light contrast of single graphenes is sufficiently high for easy detection. The theory predicts also a high contrast for single graphenes on different transparent substrates with refractive indices close to that of mica, e.g. lime glass and ITO.