Regensburg 2010 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 61: Poster II: Materials, Interfaces and Heterostructures
HL 61.7: Poster
Donnerstag, 25. März 2010, 18:00–20:00, Poster D1
Raman analysis of manipulated graphene — •Stefanie Heydrich, Michael Hirmer, Jonathan Eroms, Dieter Weiss, Tobias Korn, and Christian Schüller — Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg
We present recent results of Raman spectroscopy on unstructured graphene, gated graphene and graphene etched with anti-dot lattices.
We utilize fast, high-resolution scans to map graphene flakes on Si/SiO2-substrates. The Raman spectrum, acquired by a Triple Raman System, optimized for maximum stray light suppression, 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. Thus, a Raman image of both the flake and its structured areas is created and the chirality of a flake‘s edges can be extracted.
In unstructured flakes, the D peak is observed only at the edges, while the G peak is present everywhere on the graphene sheet.
In flakes patterned with anti-dot lattices, both D and G peak are observed everywhere on the flake. We find a stiffening of the G-peak on the structured areas compared to unstructured parts. This could be due to the strain effect. The shift is dependent on diameter and distance of the anti-dot holes.
Additionally, we study the G peak in a gated graphene flake. The gate voltage influences the charge-carrier density in the material and thus the LO-Phonon in graphene, which is coupled to this density. Therefore, by varying gate voltage, one can manipulate the G-peak position.