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

Christoph Neumann; Donatus Halpaap; Sven Reichardt; Luca Banszerus; Michael Schmitz; Kenji Watanabe; Takashi Taniguchi; Bernd Beschoten; Christoph Stampfer

doi:10.1063/1.4936995

arXiv · 1511.08984

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

Christoph Neumann·Donatus Halpaap·Sven Reichardt·Luca Banszerus·Michael Schmitz·Kenji Watanabe·Takashi Taniguchi·Bernd Beschoten·Christoph Stampfer

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Abstract

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 to 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 1/cm 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.

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Christoph Neumann, Donatus Halpaap, Sven Reichardt, Luca Banszerus, Michael Schmitz, Kenji Watanabe, Takashi Taniguchi, Bernd Beschoten, Christoph Stampfer. 2015-11-29. Probing electronic lifetimes and phonon anharmonicities in high-quality chemical vapor deposited graphene by magneto-Raman spectroscopy. https://doi.org/10.1063/1.4936995

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