Characterization of hydrogen plasma defined graphene edges

Mirko K. Rehmann, Yemliha B. Kalyoncu, Marcin Kisiel, Nikola Pascher, Franz J. Giessibl, Fabian Müller, Kenji Watanabe, Takashi Taniguchi, Ernst Meyer, Ming-Hao Liu, Dominik M. Zumbühl

Research output: Contribution to journalArticle

Abstract

We investigate the quality of hydrogen plasma defined graphene edges by Raman spectroscopy, atomic resolution AFM and low temperature electronic transport measurements. The exposure of graphite samples to a remote hydrogen plasma leads to the formation of hexagonal shaped etch pits, reflecting the anisotropy of the etch. Atomic resolution AFM reveals that the sides of these hexagons are oriented along the zigzag direction of the graphite crystal lattice and the absence of a D-peak within the noise background in the Raman spectra seems to suggest rather high quality zigzag edges. In a second step of the experiment, we investigate hexagon edges created in single layer graphene on hexagonal boron nitride and find a substantial D-peak intensity. Polarization dependent Raman measurements reveal that hydrogen plasma defined edges consist of a mixture of zigzag and armchair segments. Furthermore, electronic transport measurements were performed on hydrogen plasma defined graphene nanoribbons which indicate a high quality of the bulk but a relatively low edge quality, in agreement with the Raman data. These findings are supported by tight-binding transport simulations. Hence, further optimization of the hydrogen plasma etching technique is required to obtain pure crystalline graphene edges.

Original languageEnglish
Pages (from-to)417-424
Number of pages8
JournalCarbon
Volume150
DOIs
Publication statusPublished - 2019 Sep 1

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Graphite
Graphene
Hydrogen
Plasmas
Nanoribbons
Plasma etching
Boron nitride
Carbon Nanotubes
Crystal lattices
Raman spectroscopy
Raman scattering
Anisotropy
Polarization
Crystalline materials
Experiments
Temperature

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)

Cite this

Rehmann, M. K., Kalyoncu, Y. B., Kisiel, M., Pascher, N., Giessibl, F. J., Müller, F., ... Zumbühl, D. M. (2019). Characterization of hydrogen plasma defined graphene edges. Carbon, 150, 417-424. https://doi.org/10.1016/j.carbon.2019.05.015
Rehmann, Mirko K. ; Kalyoncu, Yemliha B. ; Kisiel, Marcin ; Pascher, Nikola ; Giessibl, Franz J. ; Müller, Fabian ; Watanabe, Kenji ; Taniguchi, Takashi ; Meyer, Ernst ; Liu, Ming-Hao ; Zumbühl, Dominik M. / Characterization of hydrogen plasma defined graphene edges. In: Carbon. 2019 ; Vol. 150. pp. 417-424.
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Rehmann, MK, Kalyoncu, YB, Kisiel, M, Pascher, N, Giessibl, FJ, Müller, F, Watanabe, K, Taniguchi, T, Meyer, E, Liu, M-H & Zumbühl, DM 2019, 'Characterization of hydrogen plasma defined graphene edges', Carbon, vol. 150, pp. 417-424. https://doi.org/10.1016/j.carbon.2019.05.015

Characterization of hydrogen plasma defined graphene edges. / Rehmann, Mirko K.; Kalyoncu, Yemliha B.; Kisiel, Marcin; Pascher, Nikola; Giessibl, Franz J.; Müller, Fabian; Watanabe, Kenji; Taniguchi, Takashi; Meyer, Ernst; Liu, Ming-Hao; Zumbühl, Dominik M.

In: Carbon, Vol. 150, 01.09.2019, p. 417-424.

Research output: Contribution to journalArticle

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AU - Giessibl, Franz J.

AU - Müller, Fabian

AU - Watanabe, Kenji

AU - Taniguchi, Takashi

AU - Meyer, Ernst

AU - Liu, Ming-Hao

AU - Zumbühl, Dominik M.

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N2 - We investigate the quality of hydrogen plasma defined graphene edges by Raman spectroscopy, atomic resolution AFM and low temperature electronic transport measurements. The exposure of graphite samples to a remote hydrogen plasma leads to the formation of hexagonal shaped etch pits, reflecting the anisotropy of the etch. Atomic resolution AFM reveals that the sides of these hexagons are oriented along the zigzag direction of the graphite crystal lattice and the absence of a D-peak within the noise background in the Raman spectra seems to suggest rather high quality zigzag edges. In a second step of the experiment, we investigate hexagon edges created in single layer graphene on hexagonal boron nitride and find a substantial D-peak intensity. Polarization dependent Raman measurements reveal that hydrogen plasma defined edges consist of a mixture of zigzag and armchair segments. Furthermore, electronic transport measurements were performed on hydrogen plasma defined graphene nanoribbons which indicate a high quality of the bulk but a relatively low edge quality, in agreement with the Raman data. These findings are supported by tight-binding transport simulations. Hence, further optimization of the hydrogen plasma etching technique is required to obtain pure crystalline graphene edges.

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Rehmann MK, Kalyoncu YB, Kisiel M, Pascher N, Giessibl FJ, Müller F et al. Characterization of hydrogen plasma defined graphene edges. Carbon. 2019 Sep 1;150:417-424. https://doi.org/10.1016/j.carbon.2019.05.015