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HL: Fachverband Halbleiterphysik
HL 81: Graphene: Transport
HL 81.2: Vortrag
Donnerstag, 17. März 2011, 14:45–15:00, POT 151
p-type doping in graphene nanostructures and electron-phonon coupling of LO-LA phonons in graphene identified by Raman spectroscopy — •Stefanie Heydrich, Michael Hirmer, Christoph Preis, Daniel Hutzler, Jonathan Eroms, Dieter Weiss, Tobias Korn, and Christian Schüller — Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg
We present recent results on graphene etched with antidot lattices and an analysis of the LO-LA phonon around the K-point and its electron-phonon coupling constant.
We utilize fast, high-resolution scans to map graphene antidot flakes on Si/SiO2-substrates. The Raman spectrum is evaluated and height, position and FWHM of the characteristic G (1580 cm−1), D (1350 cm−1) and 2D (2700 cm−1) peaks are plotted for each point.
In flakes patterned with antidot lattices, we find a stiffening of the G-peak on the structured areas compared to unstructured parts, which is due to a p-type doping in the patterned areas [1].
Additionally, we studied the LO-LA mode at the K-point in plain graphene. When exciting with higher laser energies, the peak softens and acquires a pronounced triangular shape. We also extracted the electron-phonon coupling constant [2], which yields an experimental value of about 7x10−3.
[1] S. Heydrich, M. Hirmer, C. Preis et al., Appl. Phys. Lett. 97, 043113 (2010)
[2] V. Fal′ko, private communication