Probing electronic lifetimes and phonon anharmonicities in high-quality chemical vapor deposited graphene by magneto-Raman spectroscopy

We present a magneto-Raman study on high-quality single-layer graphene grown by chemical vapor deposition (CVD) that is fully encapsulated in hexagonal boron nitride by a dry transfer technique. By analyzing the Raman D, G, and 2D peaks, we find that the structural quality of the samples is comparab...

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Veröffentlicht in:Applied physics letters 2015-12, Vol.107 (23)
Hauptverfasser: Neumann, Christoph, Halpaap, Donatus, Reichardt, Sven, Banszerus, Luca, Schmitz, Michael, Watanabe, Kenji, Taniguchi, Takashi, Beschoten, Bernd, Stampfer, Christoph
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Sprache:eng
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Zusammenfassung:We present a magneto-Raman study on high-quality single-layer graphene grown by chemical vapor deposition (CVD) that is fully encapsulated in hexagonal boron nitride by a dry transfer technique. By analyzing the Raman D, G, and 2D peaks, we find that the structural quality of the samples is comparable with state-of-the-art exfoliated graphene flakes. From B-field dependent Raman measurements, we extract the broadening and associated lifetime of the G peak due to anharmonic effects. Furthermore, we determine the decay width and lifetime of Landau level (LL) transitions from magneto-phonon resonances as a function of laser power. At low laser power, we find a minimal decay width of 140 cm−1 highlighting the high electronic quality of the CVD-grown graphene. At higher laser power, we observe an increase of the LL decay width leading to a saturation, with the corresponding lifetime saturating at a minimal value of 18 fs.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4936995