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Updated: May 20, 2025
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Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
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Charge State Tuning of Spin Defects in Hexagonal Boron Nitride
J Fraunié1, T Clua-Provost2, S Roux1
1Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France.
Nano Letters
|March 27, 2025
Summary
Optically active boron vacancies in hexagonal boron nitride (hBN) can change charge states when placed between graphene electrodes. This tunability is crucial for developing advanced 2D quantum sensors.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Information Science
Background:
- Optically active spin defects in two-dimensional (2D) van der Waals crystals, such as boron vacancies in hexagonal boron nitride (hBN), are key candidates for quantum sensing applications.
- Understanding and controlling the charge state of these defects is crucial for their effective utilization in quantum technologies.
Purpose of the Study:
- To investigate the tunability of the charge state of boron vacancies in ultrathin hBN layers.
- To explore the impact of external electrical fields on the optical properties of these defects.
Main Methods:
- Fabrication of hBN layers sandwiched between graphene electrodes.
- Application of bias voltage across the graphene electrodes to tune the charge state of boron vacancies.
- Photoluminescence measurements to monitor changes in defect charge state and optical activity.
Main Results:
- Demonstrated a transition of boron vacancies from a singly negatively charged (optically active) to a doubly negatively charged (optically inactive) state upon electrical biasing.
- Observed a photoluminescence quenching of a few percent when a bias voltage was applied.
- Confirmed the robustness of the negatively charged boron vacancy against external perpendicular electric fields.
Conclusions:
- The charge state of boron vacancies in hBN is tunable via electrical gating, impacting their optical properties.
- The negatively charged boron vacancy's stability in electric fields makes it a promising defect for integration into van der Waals heterostructures for quantum applications.
- Findings highlight the importance of charge state control for optically active defects in 2D materials.
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