Nanoindentation for Tailored Single-Photon Emitters in hBN: Influence of Annealing on Defect Stability

Quantum emitters in multilayer hexagonal boron nitride (hBN) are created by nanoindentation by using atomic force microscopy (AFM). Carbon-coated AFM tips are pushed into hBN flakes, creating localized carbon-based defects with spectrally tailored optical emission. We identify four predominant classes of single-photon emitters (SPEs) and show that our fabrication technique provides a high yield of bright emitters with narrow line widths and common dipole orientation, most of which exhibit a weak electron-phonon interaction because the SPEs are decoupled from the local atomic environment. We demonstrate that high-temperature annealing causes etching of hBN even in an inert environment. This defect engineering offers a controlled pathway for the creation of SPEs in hBN as a prerequisite for scalable quantum photonic applications.