Boron vacancies in hexagonal boron nitride (hBN) are among the most extensively studied optically active spin defects in van der Waals crystals, due to their promising potential to develop two-dimensional (2D) quantum sensors. In this letter, we demonstrate the tunability of the charge state of boron vacancies in ultrathin hBN layers, revealing a transition from the optically active singly negatively charged state to the optically inactive doubly negatively charged state when sandwiched between graphene electrodes. Notably, there is a photoluminescence quenching of a few percent upon the application of a bias voltage between the electrodes. Our findings emphasize the critical importance of considering the charge state of optically active defects in 2D materials, while also showing that the negatively charged boron vacancy remains robust against external perpendicular electric fields. This stability makes it a promising candidate for integration into various van der Waals heterostructures.
@article{arxiv.2501.18206,
title = {Charge state tuning of spin defects in hexagonal boron nitride},
author = {Jules Fraunié and Tristan Clua-Provost and Sébastien Roux and Zhao Mu and Adrien Delpoux and Grégory Seine and Delphine Lagarde and Kenji Watanabe and Takashi Taniguchi and Xavier Marie and Thomas Poirier and James H. Edgar and Jeremie Grisolia and Benjamin Lassagne and Alain Claverie and Vincent Jacques and Cedric Robert},
journal= {arXiv preprint arXiv:2501.18206},
year = {2025}
}