Light emitters in wide band gap semiconductors are of great fundamental interest and have potential as optically addressable qubits. Here we describe the discovery of a new color center in high-quality hexagonal boron nitride (h-BN) with a sharp emission line at 435 nm. The emitters are activated and deactivated by electron beam irradiation and have spectral and temporal characteristics consistent with atomic color centers weakly coupled to lattice vibrations. The emitters are conspicuously absent from commercially available h-BN and are only present in ultra-high-quality h-BN grown using a high-pressure, high-temperature Ba-B-N flux/solvent, suggesting that these emitters originate from impurities or related defects specific to this unique synthetic route. Our results imply that the light emission is activated and deactivated by electron beam manipulation of the charge state of an impurity-defect complex.
@article{arxiv.1904.12107,
title = {Blue-Light-Emitting Color Centers in High-Quality Hexagonal Boron Nitride},
author = {Brian Shevitski and S. Matt Gilbert and Christopher T. Chen and Christoph Kastl and Edward S. Barnard and Ed Wong and D. Frank Ogletree and Kenji Watanabe and Takashi Taniguchi and Alex Zettl and Shaul Aloni},
journal= {arXiv preprint arXiv:1904.12107},
year = {2019}
}