Quantum Efficiency\nand Vertical Position of Quantum\nEmitters in hBN Determined by Purcell Effect in Hybrid Metal-Dielectric\nPlanar Photonic Structures

Color centers in hexagonal boron nitride (hBN) advantageously\ncombine\nexcellent photophysical properties with the potential for integration\nin highly compact devices. Progress toward scalable integration necessitates\na high quantum efficiency and an efficient photon collection. In this\ncontext, we compare the optical characteristics of individual hBN\ncolor centers generated by electron irradiation in two different electromagnetic\nenvironments. We keep track of well-identified emitters that we characterize\nbefore and after the dry transfer of exfoliated crystals. This comparison\nprovides information about their quantum efficiency, which we find\nclose to unity, as well as their vertical position in the crystal\nwith nanometric precision, which we find away from the flake surfaces.\nOur work suggests hybrid dielectric-metal planar structures as an\nefficient tool for characterizing quantum emitters in addition to\nimproving the count rate and can be generalized to other emitters\nin 2D materials or in planar photonic structures.