Color centers in 2-dimensional hexagonal boron nitride (h-BN) have recently emerged as stable and bright single-photon emitters (SPEs) operating at room temperature. In this study, we combine theory and experiment to show that vacancy-based SPEs selectively form at nano-scale wrinkles in h-BN with its optical dipole preferentially aligned to the wrinkle direction. By using density functional theory calculations, we find that the wrinkle's curvature plays a crucial role in localizing vacancy-based SPE candidates and aligning the defect's symmetry plane to the wrinkle direction. By performing optical measurements on SPEs created in h-BN single-crystal flakes, we experimentally confirm the wrinkle-induced generation of SPEs and their polarization alignment to the wrinkle direction. Our results not only provide a new route to controlling the atomic position

Colour centres of hexagonal boron nitride (h-BN) have been discovered as promising and practical single photon sources due to their high brightness and narrow spectral linewidth at room-temperature. In order to realize h-BN based photonic quantum communications, the ability to electrically activate the single photon fluorescence using an external electric field is crucial. In this work, we show the electrical switching of the photoluminescence from h-BN quantum emitters, enabled by the controllable electron transfer from the nearby charge reservoir. By tuning the Fermi level of graphene next to the h-BN defects, we observed luminescence brightening of a quantum emitter upon the application of a voltage due to the direct charge state manipulation. In addition, the correlation measurement of the single photon sources with the graphene’s Raman spectroscopy allows us to extract the exact charge transition level of quantum emitters, providing the information on the crystallographic nature of the defect structure. With the complete on-off switching of emission intensity of h-BN quantum emitters using a voltage, our result paves the way for the van der Waals colour centre based photonic quantum information processing, cryptography and memory applications.