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O: Fachverband Oberflächenphysik
O 23: Graphene: Electronic Properties and Transport (jointly with HL, MA and TT)
O 23.3: Vortrag
Montag, 11. März 2013, 16:30–16:45, H17
Effects of strain on the excitonic Fano resonance in the optical spectrum of graphene — •Daniela Ullrich1,2, Patrick Herlinger1, Harald Giessen2, Jurgen Smet1, and Markus Lippitz1,2 — 1Max Planck Institute for Solid State Research, Stuttgart — 24th Physics Institute, University of Stuttgart
Using transmission and reflection spectroscopy we examine the optical response of graphene from the visible to the UV regime. The absorbance spectrum of free-standing graphene is dominated by an asymmetric peak in the UV at about 4.7 eV. We show that this resonance can be described by a simple Fano model which includes an excitonic state beneath the saddle point of graphene's band structure [1]. When strain is applied to a graphene sheet, the symmetry of the lattice and thus also of the band structure is broken. As predicted recently [2], this should result in a splitting of the absorbance peak in the optical spectrum as well as a strong dependence on polarization and lattice orientation. Here, we present our findings on the effects of strain on the Raman and reflectivity spectra of graphene on flexible substrates.
[1] Chae et al., Nano Lett. 11, 1379 (2011)
[2] Liang et al., J. Mater. Res. 27, 403 (2012)