Article Benchmarking the integration of hexagonal boron nitride crystals and thin films into graphene-based van der Waals heterostructures

Taoufiq Ouaj ORCID ; Christophe Arnold ORCID ; Jon Azpeitia ORCID ; Sunaja Baltic ; Julien Barjon ORCID ; José Cascales ORCID ; Huanyao Cun ORCID ; David Esteban ORCID ; Mar Garcia-Hernandez ORCID ; Vincent Garnier ; Subodh K Gautam ; Thomas Greber ORCID ; Said Said Hassani ; Adrian Hemmi ; Ignacio Jiménez ORCID ; Catherine Journet ORCID ; Paul Kögerler ORCID ; Annick Loiseau ORCID ; Camille Maestre ORCID ; Marvin Metzelaars ORCID ; Philipp Schmidt ORCID ; Christoph Stampfer ORCID ; Ingrid Stenger ORCID ; Philippe Steyer ; Takashi Taniguchi SAMURAI ORCID ; Bérangère Toury ORCID ; Kenji Watanabe SAMURAI ORCID ; Bernd Beschoten ORCID

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Taoufiq Ouaj, Christophe Arnold, Jon Azpeitia, Sunaja Baltic, Julien Barjon, José Cascales, Huanyao Cun, David Esteban, Mar Garcia-Hernandez, Vincent Garnier, Subodh K Gautam, Thomas Greber, Said Said Hassani, Adrian Hemmi, Ignacio Jiménez, Catherine Journet, Paul Kögerler, Annick Loiseau, Camille Maestre, Marvin Metzelaars, Philipp Schmidt, Christoph Stampfer, Ingrid Stenger, Philippe Steyer, Takashi Taniguchi, Bérangère Toury, Kenji Watanabe, Bernd Beschoten. Benchmarking the integration of hexagonal boron nitride crystals and thin films into graphene-based van der Waals heterostructures. 2D Materials. 2025, 12 (1), 015017. https://doi.org/10.1088/2053-1583/ad96c9

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(abstract)

We present a benchmarking protocol that combines the characterization of boron nitride crystals and films with the evaluation of the electronic quality of graphene on these substrates. Our study includes hBN crystals grown under different conditions (atmospheric pressure high temperature, pressure controlled furnace) and scalable BN films deposited by either chemical or physical vapor deposition (CVD or PVD). We explore the complete process from boron nitride growth, over its optical characterization by time-resolved cathodoluminescence (TRCL), to the optical and electronic characterization of graphene by Raman spectroscopy after encapsulation and Hall bar processing. Within our benchmarking protocol we achieve a homogeneous electronic performance within each Hall bar device through a fast and reproducible processing routine. We find that a free exciton lifetime of 1ns measured on as-grown hBN crystals by TRCL is sufficient to achieve high graphene room temperature charge carrier mobilities of 80, 000 cm2 /(Vs) at a carrier density of |n| = 1 × 1012 cm−2 , while re- spective exciton lifetimes around 100ps yield mobilities up to 30,000cm2/(Vs). For scalable PVD-grown BN films, we measure carrier mobilities exceeding 10,000cm2/(Vs) which correlates with a graphene Raman 2D peak linewidth of 22cm−1. Our work highlights the importance of the Raman 2D linewidth of graphene as a critical metric that effectively assesses the interface quality (i.e. surface roughness) to the BN substrate, which directly affects the charge carrier mobility of graphene. Graphene 2D linewidth analysis is suitable for all BN substrates and is particularly advantageous when TRCL or Raman spectroscopy cannot be applied to specific BN materials such as amorphous or thin films. This underlines its superior role in the evaluation of BN crystals and films for the use of high-mobility graphene devices.

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Keyword: Boron nitride, electronic properties, graphene

Date published: 2025-01-01

Publisher: IOP Publishing

Journal:

  • 2D Materials (ISSN: 20531583) vol. 12 issue. 1 015017

Funding:

  • European Research Council 820254
  • Graphene Flagship 881603
  • Universtiy of Zurch FK-20-206 114
  • World Premier International Research Center Initiative, MEXT, Japan
  • Deutsche Forschungsgemeinschaft 2004/1 - 390534769
  • Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung CRSK-2_220582
  • Japan Society for the Promotion of Science 21H05233

Manuscript type: Publisher's version (Version of record)

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First published URL: https://doi.org/10.1088/2053-1583/ad96c9

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Updated at: 2025-02-03 12:30:33 +0900

Published on MDR: 2025-02-03 12:30:33 +0900

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