Photophysics of blue quantum emitters in hexagonal Boron Nitride

TL;DR

This study provides a detailed photophysical characterization of blue-emitting quantum defects in hexagonal boron nitride, revealing their electronic structure and potential for scalable quantum photonic devices.

Contribution

It offers new insights into the level structure and photodynamics of blue quantum emitters in hBN, including fabrication methods and theoretical analysis of their electronic states.

Findings

Emitters exhibit narrow-band luminescence at 436 nm.

Photon statistics suggest absence of a metastable state.

Theoretical analysis indicates a fully occupied defect state in the lower band gap.

Abstract

Colour centres in hexagonal boron nitride (hBN) have emerged as intriguing contenders for integrated quantum photonics. In this work, we present detailed photophysical analysis of hBN single emitters emitting at the blue spectral range. The emitters are fabricated by different electron beam irradiation and annealing conditions and exhibit narrow-band luminescence centred at 436 nm. Photon statistics as well as rigorous photodynamics analysis unveils potential level structure of the emitters, which suggests lack of a metastable state, supported by a theoretical analysis. The potential defect can have an electronic structure with fully occupied defect state in the lower half of the hBN band gap and empty defect state in the upper half of the band gap. Overall, our results are important to understand the photophysical properties of the emerging family of blue quantum emitters in hBN as potential sources for scalable quantum photonic applications.