Revealing multiple classes of stable quantum emitters in hexagonal boron nitride with correlated optical and electron microscopy


Defects in hexagonal boron nitride (hBN) exhibit high-brightness, room-temperature quantum emission, but their large spectral variability and unknown local structure challenge their technological utility. Here, we directly correlate hBN quantum emission with local strain using a combination of photoluminescence (PL), cathodoluminescence (CL) and nanobeam electron diffraction. Across 40 emitters, we observe zero phonon lines (ZPLs) in PL and CL ranging from 540 to 720 nm. CL mapping reveals that multiple defects and distinct defect species located within an optically diffraction-limited region can each contribute to the observed PL spectra. Local strain maps indicate that strain is not required to activate the emitters and is not solely responsible for the observed ZPL spectral range. Instead, at least four distinct defect classes are responsible for the observed emission range, and all four classes are stable upon both optical and electron illumination. Our results provide a foundation for future atomic-scale optical characterization of colour centres.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Correlated optical and electron characterization of quantum emitters in hBN.
Fig. 2: Cathodoluminescence mapping reveals multiple and distinct quantum-emitter species within a diffraction-limited optical spot.
Fig. 3: Correlating stable emitter PL and CL spectra reveals two types of behaviour.
Fig. 4: Correlating quantum emission with local strain.
Fig. 5: Emitter classification.

Data availability

All strain analysis data presented in Fig. 5 are included in Supplementary Information. Due to large file sizes, strain mapping and all other electron microscopy source data are available from the corresponding authors on request.


  1. 1.

    Kucsko, G. et al. Nanometre-scale thermometry in a living cell. Nature 500, 54–58 (2013).

    CAS  Article  Google Scholar 

  2. 2.

    Taylor, J. et al. High-sensitivity diamond magnetometer with nanoscale resolution. Nat. Phys. 4, 810–816 (2008).

    CAS  Article  Google Scholar 

  3. 3.

    Aslam, N. et al. Nanoscale nuclear magnetic resonance with chemical resolution. Science 357, 67–71 (2017).

    CAS  Article  Google Scholar 

  4. 4.

    Wehner, S., Elkouss, D. & Hanson, R. Quantum internet: a vision for the road ahead. Science 362, eaam9288 (2018).

    Article  Google Scholar 

  5. 5.

    Liao, S.-K. et al. Satellite-to-ground quantum key distribution. Nature 549, 43–47 (2017).

    CAS  Article  Google Scholar 

  6. 6.

    Awschalom, D. D., Hanson, R., Wrachtrup, J. & Zhou, B. B. Quantum technologies with optically interfaced solid-state spins. Nat. Photonics 12, 516–527 (2018).

    CAS  Article  Google Scholar 

  7. 7.

    Atatüre, M., Englund, D., Vamivakas, N., Lee, S.-Y. & Wrachtrup, J. Material platforms for spin-based photonic quantum technologies. Nat. Rev. Mater. 3, 38–51 (2018).

    Article  Google Scholar 

  8. 8.

    Tran, T. T., Bray, K., Ford, M. J., Toth, M. & Aharonovich, I. Quantum emission from hexagonal boron nitride monolayers. Nat. Nanotechnol. 11, 37–41 (2016).

    CAS  Article  Google Scholar 

  9. 9.

    Jungwirth, N. R. et al. Temperature dependence of wavelength selectable zero-phonon emission from single defects in hexagonal boron nitride. Nano Letters 16, 6052–6057 (2016).

    CAS  Article  Google Scholar 

  10. 10.

    Grosso, G. et al. Tunable and high-purity room temperature single-photon emission from atomic defects in hexagonal boron nitride. Nat. Commun. 8, 705 (2017).

    Article  Google Scholar 

  11. 11.

    Sontheimer, B. et al. Photodynamics of quantum emitters in hexagonal boron nitride revealed by low-temperature spectroscopy. Phys. Rev. B 96, 121202 (2017).

    Article  Google Scholar 

  12. 12.

    Exarhos, A. L., Hopper, D. A., Grote, R. R., Alkauskas, A. & Bassett, L. C. Optical signatures of quantum emitters in suspended hexagonal boron nitride. ACS Nano 11, 3328–3336 (2017).

    CAS  Article  Google Scholar 

  13. 13.

    Martínez, L. et al. Efficient single photon emission from a high-purity hexagonal boron nitride crystal. Phys. Rev. B 94, 121405 (2016).

    Article  Google Scholar 

  14. 14.

    Tran, T. T. et al. Robust multicolor single photon emission from point defects in hexagonal boron nitride. ACS Nano 10, 7331–7338 (2016).

    CAS  Article  Google Scholar 

  15. 15.

    Choi, S. et al. Engineering and localization of quantum emitters in large hexagonal boron nitride layers. ACS Appl. Mater. Interfaces 8, 29642–29648 (2016).

    CAS  Article  Google Scholar 

  16. 16.

    Chejanovsky, N. et al. Structural attributes and photodynamics of visible spectrum quantum emitters in hexagonal boron nitride. Nano Lett. 16, 7037–7045 (2016).

    CAS  Article  Google Scholar 

  17. 17.

    Jungwirth, N. R. & Fuchs, G. D. Optical absorption and emission mechanisms of single defects in hexagonal boron nitride. Phys. Rev. Lett. 119, 057401 (2017).

    Article  Google Scholar 

  18. 18.

    Schell, A. W., Svedendahl, M. & Quidant, R. Quantum emitters in hexagonal boron nitride have spectrally tunable quantum efficiency. Adv. Mater. 30, 1704237 (2018).

    Article  Google Scholar 

  19. 19.

    Reimers, J. R., Sajid, A., Kobayashi, R. & Ford, M. J. Understanding and calibrating density-functional-theory calculations describing the energy and spectroscopy of defect sites in hexagonal boron nitride. J. Chem. Theory Comput. 14, 1602–1613 (2018).

    CAS  Article  Google Scholar 

  20. 20.

    Tawfik, S. A. et al. First-principles investigation of quantum emission from hBN defects. Nanoscale 9, 13575–13582 (2017).

    CAS  Article  Google Scholar 

  21. 21.

    Feng, J. et al. Imaging of optically active defects with nanometer resolution. Nano Lett. 18, 1739–1744 (2018).

    CAS  Article  Google Scholar 

  22. 22.

    Bourrellier, R. et al. Bright uv single photon emission at point defects in h-bn. Nano Lett. 16, 4317–4321 (2016).

    CAS  Article  Google Scholar 

  23. 23.

    Meuret, S. et al. Photon bunching in cathodoluminescence. Phys. Rev. Lett. 114, 197401 (2015).

    CAS  Article  Google Scholar 

  24. 24.

    Alem, N. et al. Atomically thin hexagonal boron nitride probed by ultrahigh-resolution transmission electron microscopy. Phys. Rev. B 80, 155425 (2009).

    Article  Google Scholar 

  25. 25.

    Jin, C., Lin, F., Suenaga, K. & Iijima, S. Fabrication of a freestanding boron nitride single layer and its defect assignments. Phys. Rev. Lett. 102, 195505 (2009).

    Article  Google Scholar 

  26. 26.

    Wong, D. et al. Characterization and manipulation of individual defects in insulating hexagonal boron nitride using scanning tunnelling microscopy. Nat. Nanotechnol. 10, 949–953 (2015).

    CAS  Article  Google Scholar 

  27. 27.

    Lin, W.-H. et al. Atomic-scale structural and chemical characterization of hexagonal boron nitride layers synthesized at the wafer-scale with monolayer thickness control. Chem. Mater. 29, 4700–4707 (2017).

    CAS  Article  Google Scholar 

  28. 28.

    Barja, S. et al. Identifying substitutional oxygen as a prolific point defect in monolayer transition metal dichalcogenides. Nat. Commun. 10, 3382 (2019).

    Article  Google Scholar 

  29. 29.

    Cassabois, G., Valvin, P. & Gil, B. Hexagonal boron nitride is an indirect bandgap semiconductor. Nat. Photonics 10, 262–266 (2016).

    CAS  Article  Google Scholar 

  30. 30.

    Koperski, M., Nogajewski, K. & Potemski, M. Single photon emitters in boron nitride: more than a supplementary material. Opt. Commun. 411, 158–165 (2018).

    CAS  Article  Google Scholar 

  31. 31.

    de la Peña, F. et al. hyperspy/hyperspy v.1.4.1 (Zenodo, 2018);

  32. 32.

    Katzir, A., Suss, J., Zunger, A. & Halperin, A. Point defects in hexagonal boron nitride. I. EPR, thermoluminescence, and thermally-stimulated-current measurements. Phys. Rev. B 11, 2370 (1975).

    CAS  Article  Google Scholar 

  33. 33.

    Xue, Y. et al. Anomalous pressure characteristics of defects in hexagonal boron nitride flakes. ACS Nano 12, 7127–7133 (2018).

    CAS  Article  Google Scholar 

  34. 34.

    Vogl, T., Doherty, M. W., Buchler, B. C., Lu, Y. & Lam, P. K. Atomic localization of quantum emitters in multilayer hexagonal boron nitride. Nanoscale 11, 14362–14371 (2019).

    CAS  Article  Google Scholar 

  35. 35.

    Kotakoski, J., Jin, C., Lehtinen, O., Suenaga, K. & Krasheninnikov, A. Electron knock-on damage in hexagonal boron nitride monolayers. Phys. Rev. B 82, 113404 (2010).

    Article  Google Scholar 

  36. 36.

    Meyer, J. C., Chuvilin, A., Algara-Siller, G., Biskupek, J. & Kaiser, U. Selective sputtering and atomic resolution imaging of atomically thin boron nitride membranes. Nano Lett. 9, 2683–2689 (2009).

    CAS  Article  Google Scholar 

  37. 37.

    Weston, L., Wickramaratne, D., Mackoit, M., Alkauskas, A. & Van de Walle, C. G. Native point defects and impurities in hexagonal boron nitride. Phys. Rev. B 97, 214104 (2018).

    CAS  Article  Google Scholar 

  38. 38.

    Yin, L.-C., Cheng, H.-M. & Saito, R. Triangle defect states of hexagonal boron nitride atomic layer: density functional theory calculations. Phys. Rev. B 81, 153407 (2010).

    Article  Google Scholar 

Download references


The authors acknowledge useful discussions about strain mapping with T. Pekin (Humboldt-Universität zu Berlin) and about CL–PL correlations with C. McLellan (Stanford). TEM imaging and spectroscopy were performed at the Stanford Nano Shared Facilities and Stanford Soft & Hybrid Materials Facility. The PL, TEM experiments and theoretical modelling were supported by the DOE ‘Photonics at Thermodynamic Limits’ Energy Frontier Research Center under grant no. DE-SC0019140. F.H. gratefully acknowledges the support of the Diversifying Academia, Recruiting Excellence (DARE) Doctoral Fellowship Program by Stanford University. J.V. acknowledges the support the NSF Quantum Leap EAGER grant no. DMR 1838380. T.F.H. and L.Y. also acknowledge support from the Betty and Gordon Moore Foundation EPiQS Initiative through grant no. GBMF4545.

Author information




F.H., L.Y., T.F.H. and J.A.D. conceived the project. F.H. made the samples and performed the PL and TEM experiments. J.L.Z., L.Y. and F.H. performed the second-order correlation measurements under the supervision of J.V. C.J.C. and P.N. performed the theoretical calculations. A.F.M. assisted in strain map data collection. M.N. and I.A. assisted in sample preparation. F.H. and J.A.D. wrote the draft. J.A.D. supervised the project. All co-authors discussed the results and provided useful feedback on the manuscript.

Corresponding authors

Correspondence to Fariah Hayee or Jennifer A. Dionne.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended Data Fig. 1 Higher energy lines associated with the 580-590 nm emitters.

a, HAADF and decomposed CL spectral weight maps of the emitter with ZPL at 578 nm in Fig. 4a of main text. b, CL spectral components showing higher energy peaks similar to that in Fig. 2a. c, HAADF and CL spectral weight maps of the emitter E6 in Fig. 3a with ZPL at 590 nm. d, CL spectral components for emitter in (c). Each pixel in the CL weight maps is 15 nm. For both emitters here, the PL spectrum has two probable phonon-sidebands, a similar spectral signature to the emitter in the main text Fig. 2a. All these three emitters have four higher energy (UV-blue) peaks in their CL spectrum. For the particular emitter in panels (c-d), spectral decomposition shows that the 420 nm emitter is located 80 nm away from the 590 nm emitter. However, the 460 nm, 500 nm and 532 nm peaks are localized to the same 15 nm bright pixel as the 590 nm peak.

Supplementary information

Supplementary Information

Supplementary Figs. 1–13 and discussion sections 1–10.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Hayee, F., Yu, L., Zhang, J.L. et al. Revealing multiple classes of stable quantum emitters in hexagonal boron nitride with correlated optical and electron microscopy. Nat. Mater. 19, 534–539 (2020).

Download citation

Further reading