Point defects in h-BN: Towards a two-dimensional spin–photon interface

Spin-active point defects in hexagonal boron nitride (h-BN) are emerging as a promising platform for scalable quantum technologies, both as sources of single photons and as spin–photon interfaces. As a host material, h-BN can be easily integrated into quantum photonic circuits and its two-dimensional nature means defects can be in close proximity to the surface, allowing for high-resolution quantum sensing. This review summarises recent progress in the understanding and engineering of these defects, and explores their suitability to different quantum technology applications. Key outstanding challenges, such as prolonging spin coherence and developing a method of deterministic defect creation, are identified, and comparisons are made to other solid-state platforms – particularly nitrogen–vacancy centres in diamond.