Imaging of Optically Active Defects with Nanometer Resolution

Abstract

Point defects significantly influence the optical and electrical properties of solid-state materials due to their interactions with charge carriers, which reduce the band-to-band optical transition energy. There has been a demand for developing direct optical imaging methods that would allow in situ characterization of individual defects with nanometer resolution. Here, we demonstrate the localization and quantitative counting of individual optically active defects in monolayer hexagonal boron nitride using single molecule localization microscopy. By exploiting the blinking behavior of defect emitters to temporally isolate multiple emitters within one diffraction limited region, we could resolve two defect emitters with a point-to-point distance down to ten nanometers. The results and conclusion presented in this work add unprecedented dimensions toward future applications of defects in quantum information processing and biological imaging.

Wide-Field Spectral Super-Resolution Mapping of Optically Active Defects in Hexagonal Boron Nitride

“…Another interesting feature of the emitters investigated here is their blinking kinetics, also observed in several other studies 18,34,37 , but contrasting with other reports of long-term emission stability for the emitters in hBN 10,36 . To gather more insight into this blinking behavior, we plot An important question remains to understand the reasons for the spectral heterogeneity evidenced in our study and the presence of different emission lines and defects states in CVD grown hBN and irradiated bulk hBN crystals.…”

“…Continuous green laser illumination of the flakes leads to photoswitching (blinking) of the emitters between bright and dark states 18 . As shown in Fig.…”

Phonon sidebands of color centers in hexagonal boron nitride

“…35 37,38 We could not find any calculations of the expected splitting, that we measure to be ∼0.4eV, which seems large. Furthermore, the neutral boron vacancy V 0 B is predicted to have no optically active transitions below 3.5eV, 39,40 and the charge transition level for the neutral to negative state of the boron vacancy has been calculated (with reference to the valance band maxima) 1.5eV, 41 and 2.1eV 42 for bulk hBN, and 2.4eV 38 for a monolayer. This is in agreement with our model of photoionization and recharging.…”

Tunnel spectroscopy of localised electronic states in hexagonal boron nitride

“…They could also be introduced unintentionally during mechanical exfoliation of hBN and/or its incorporation within a multilayer vdW heterostructure. Electronic transitions between localised states with energies within the large band gap of hBN are also of interest, because they are single quantum emitters of visible light [28][29][30][31][32][33][34][35][36][37][38][39][40] and thus have potential for applications in nanophotonics, optoelectronics and quantum information processing. Recently, localised states have been shown to affect the electronic properties of spintronic 41 and superconducting 42 van der Waals devices.…”