Deterministic Quantum Emitter Formation in Hexagonal Boron Nitride via Controlled Edge Creation

Quantum emitters (QEs) in 2D hexagonal boron nitride (hBN) are extremely bright, stable under harsh conditions, and have the potential for strong coupling to hybrid devices due to their 2D host crystal. However, due to the difficulty of precisely creating these QEs, this potential for coupling into hybrid devices has been difficult to utilize. Motivated by recent studies showing that QEs in hBN tend to form at edges, we use a focused ion beam (FIB) to mill patterns in hBN. We optically characterize these milled hBN sheets and find that optimal FIB parameters create single QEs with a nearly Poisson-limited yield of 35%, and a 94% chance of creating at least one QE. We use atomic force microscopy to understand why these parameters are optimal and find that single QE yield is highest with a smooth milling profile on smooth hBN. This technique dramatically broadens the usefulness and convenience of hBN QEs – enabling facile integration into optoelectronic devices to fully take advantage of the appealing hBN QEs.