Looking behind the scenes: Raman spectroscopy of top-gated epitaxial graphene through the substrate

Language
en
Document Type
Article
Issue Date
2022-02-14
First published
2013-11-01
Issue Year
2013
Authors
Fromm, F
Wehrfritz, P
Hundhausen, M
Seyller, Th
Editor
Publisher
IOP Publishing
Abstract

Abstract Raman spectroscopy is frequently used to study the properties of epitaxial graphene grown on silicon carbide (SiC). In this work, we present a confocal micro-Raman study of epitaxial graphene on SiC(0001) in top-down geometry, i.e. in a geometry where both the primary laser light beam as well as the back-scattered light is guided through the SiC substrate. Compared to the conventional top-up configuration, in which confocal micro-Raman spectra are measured from the air side, we observe a significant intensity enhancement in top-down configuration, indicating that most of the Raman-scattered light is emitted into the SiC substrate. The intensity enhancement is explained in terms of dipole radiation at a dielectric surface. The new technique opens the possibility to probe graphene layers in devices where the graphene layer is covered by non-transparent materials. We demonstrate this by measuring gate-modulated Raman spectra of a top-gated epitaxial graphene field effect device. Moreover, we show that these measurements enable us to disentangle the effects of strain and charge on the positions of the prominent Raman lines in epitaxial graphene on SiC.

Journal Title
New Journal of Physics
Volume
15
Issue
11
Citation
New Journal of Physics 15.11 (2013): 113006. <https://iopscience.iop.org/article/10.1088/1367-2630/15/11/113006>
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