Identifying carbon as the source of visible single-photon emission from hexagonal boron nitride

Abstract

Single-photon emitters (SPEs) in hexagonal boron nitride (hBN) have garnered increasing attention over the last few years due to their superior optical properties. However, despite the vast range of experimental results and theoretical calculations, the defect structure responsible for the observed emission has remained elusive. Here, by controlling the incorporation of impurities into hBN via various bottom-up synthesis methods and directly through ion implantation, we provide direct evidence that the visible SPEs are carbon related. Room-temperature optically detected magnetic resonance is demonstrated on ensembles of these defects. We perform ion-implantation experiments and confirm that only carbon implantation creates SPEs in the visible spectral range. Computational analysis of the simplest 12 carbon-containing defect species suggest the negatively charged \({\rm{V}}_{\rm{B}}{\rm{C}}_{\rm{N}}^ -\) defect as a viable candidate and predict that out-of-plane deformations make the defect environmentally sensitive. Our results resolve a long-standing debate about the origin of single emitters at the visible range in hBN and will be key to the deterministic engineering of these defects for quantum photonic devices.

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Fig. 1: Photoluminescence from MOVPE hBN samples.
Fig. 2: Photoluminescence from hBN samples fabricated by MBE and HOPG conversion.
Fig. 3: MOVPE hBN (TEB 10) samples implanted with carbon.
Fig. 4: Wide-field imaging of ion-implanted MOVPE and exfoliated hBN.
Fig. 5: Computational modelling.

Data availability

Source data for most experimental and theoretical data for this work are provided. Confocal maps and wide-field images are available from the corresponding author upon request due to their size. Source data are provided with this paper.

References

  1. 1.

    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 

  2. 2.

    Lukin, D. M. et al. 4H-silicon-carbide-on-insulator for integrated quantum and nonlinear photonics. Nat. Photon. 14, 330–334 (2020).

    CAS  Article  Google Scholar 

  3. 3.

    Evans, R. E. et al. Photon-mediated interactions between quantum emitters in a diamond nanocavity. Science 362, 662–665 (2018).

    CAS  Article  Google Scholar 

  4. 4.

    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 

  5. 5.

    Caldwell, J. D. et al. Photonics with hexagonal boron nitride. Nat. Rev. Mater. 4, 552–567 (2019).

    CAS  Article  Google Scholar 

  6. 6.

    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 

  7. 7.

    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 

  8. 8.

    Proscia, N. V. et al. Near-deterministic activation of room temperature quantum emitters in hexagonal boron nitride. Optica 5, 1128–1134 (2018).

    CAS  Article  Google Scholar 

  9. 9.

    Mendelson N., Doherty M., Toth M., Aharonovich I., Tran T. T. Strain-induced modification of the optical characteristics of quantum emitters in hexagonal boron nitride. Adv. Mater. 32, 1908316 (2020).

  10. 10.

    Noh, G. et al. Stark tuning of single-photon emitters in hexagonal boron nitride. Nano Lett. 18, 4710–4715 (2018).

    CAS  Article  Google Scholar 

  11. 11.

    Nikolay, N. et al. Very large and reversible Stark-shift tuning of single emitters in layered hexagonal boron nitride. Phys. Rev. Appl. 11, 041001 (2019).

    CAS  Article  Google Scholar 

  12. 12.

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

    CAS  Article  Google Scholar 

  13. 13.

    Kianinia, M. et al. Robust solid-state quantum system operating at 800 K. ACS Photon. 4, 768–773 (2017).

    CAS  Article  Google Scholar 

  14. 14.

    Dietrich A., Doherty M. W., Aharonovich I., Kubanek A. Solid-state single photon source with Fourier transform limited lines at room temperature. Phys. Rev. B 101, 081401 (2020).

  15. 15.

    Konthasinghe K. et al. Rabi oscillations and resonance fluorescence from a single hexagonal boron nitride quantum emitter. Optica 6, 542–548 (2019).

  16. 16.

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

  17. 17.

    Gottscholl A. et al. Initialization and read-out of intrinsic spin defects in a van der Waals crystal at room temperature. Nat. Mater. 19, 540–545 (2020).

  18. 18.

    Chejanovsky N. et al. Single spin resonance in a van der Waals embedded paramagnetic defect. Preprint at https://arxivorg/abs/190605903 (2019).

  19. 19.

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

    CAS  Article  Google Scholar 

  20. 20.

    Mackoit-Sinkevičienė M., Maciaszek M., Van de Walle C. G., Alkauskas A. Carbon dimer defect as a source of the 4.1 eV luminescence in hexagonal boron nitride. Appl. Phys. Lett. 115, 212101 (2019).

  21. 21.

    Sajid, A., Reimers, J. R. & Ford, M. J. Defect states in hexagonal boron nitride: assignments of observed properties and prediction of properties relevant to quantum computation. Phys. Rev. B 97, 064101 (2018).

    CAS  Article  Google Scholar 

  22. 22.

    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 

  23. 23.

    Abdi, M., Chou, J.-P., Gali, A. & Plenio, M. B. Color centers in hexagonal boron nitride monolayers: a group theory and ab initio analysis. ACS Photon. 5, 1967–1976 (2018).

    CAS  Article  Google Scholar 

  24. 24.

    Breitweiser, S. A. et al. Efficient optical quantification of heterogeneous emitter ensembles. ACS Photon. 7, 288–295 (2019).

    Article  Google Scholar 

  25. 25.

    Vogl, T., Campbell, G., Buchler, B. C., Lu, Y. & Lam, P. K. Fabrication and deterministic transfer of high-quality quantum emitters in hexagonal boron nitride. ACS Photon. 5, 2305–2312 (2018).

    CAS  Article  Google Scholar 

  26. 26.

    Onodera, M. et al. Carbon-rich domain in hexagonal boron nitride: carrier mobility degradation and anomalous bending of the Landau fan diagram in adjacent graphene. Nano Lett. 19, 7282–7286 (2019).

    CAS  Article  Google Scholar 

  27. 27.

    Chugh D. et al Flow modulation epitaxy of hexagonal boron nitride. 2D Mater. 5, 045018 (2018).

  28. 28.

    Mendelson, N. et al. Engineering and tuning of quantum emitters in few-layer hexagonal boron nitride. ACS Nano 13, 3132–3140 (2019).

    CAS  Article  Google Scholar 

  29. 29.

    Stern, H. L. et al. Spectrally resolved photodynamics of individual emitters in large-area monolayers of hexagonal boron nitride. ACS Nano 13, 4538–4547 (2019).

    CAS  Article  Google Scholar 

  30. 30.

    Wigger D. et al. Phonon-assisted emission and absorption of individual color centers in hexagonal boron nitride. 2D Mater. 6, 035006 (2019).

  31. 31.

    Feldman M. A. et al. Phonon-induced multicolor correlations in hBN single-photon emitters. Phys. Rev. B 99, 020101 (2019).

  32. 32.

    Cheng T. S. et al. High-temperature molecular beam epitaxy of hexagonal boron nitride layers. J. Vac. Sci. Technol. B Nanotechnol Microelectron 36, 02D103 (2018).

  33. 33.

    Hernández-Mínguez A., Lähnemann J., Nakhaie S., Lopes J. M. J., Santos P. V. Luminescent defects in a few-layer h-BN film grown by molecular beam epitaxy. Phys. Rev. Appl. 10, 044031 (2018).

  34. 34.

    de Heer, W. A. et al. Large area and structured epitaxial graphene produced by confinement controlled sublimation of silicon carbide. Proc. Natl Acad. Sci. USA 108, 16900–16905 (2011).

    Article  Google Scholar 

  35. 35.

    Rousseas, M. et al. Synthesis of highly crystalline sp2-bonded boron nitride aerogels. ACS Nano 7, 8540–8546 (2013).

    CAS  Article  Google Scholar 

  36. 36.

    Schué L., Stenger I., Fossard F., Loiseau A., Barjon J. Characterization methods dedicated to nanometer-thick hBN layers. 2D Mater. 4, 015028 (2016).

  37. 37.

    Orwa, J. O. et al. An upper limit on the lateral vacancy diffusion length in diamond. Diam. Relat. Mater. 24, 6−10 (2012).

    CAS  Article  Google Scholar 

  38. 38.

    Casida M. E. in Recent Advances in Density Functional Methods (ed. Chong, D. P.) Part 1, 155–192 (World Scientific, 1995).

  39. 39.

    Yanai, T., Tew, D. P. & Handy, N. C. A new hybrid exchange-correlation functional using the Coulomb-attenuating method (CAM-B3LYP). Chem. Phys. Lett. 393, 51–57 (2004).

    CAS  Article  Google Scholar 

  40. 40.

    Heyd, J., Scuseria, G. E. & Ernzerhof, M. Hybrid functionals based on a screened Coulomb potential. J. Chem. Phys. 118, 8207–8215 (2003).

    CAS  Article  Google Scholar 

  41. 41.

    Stanton, J. F. & Bartlett, R. J. The equation of motion coupled‐cluster method. A systematic biorthogonal approach to molecular excitation energies, transition probabilities, and excited state properties. J. Chem. Phys. 98, 7029–7039 (1993).

    CAS  Article  Google Scholar 

  42. 42.

    Cornell, W. D. et al. A second generation force field for the simulation of proteins, nucleic acids, and organic molecules. J. Am. Chem. Soc. 117, 5179–5197 (1995).

    CAS  Article  Google Scholar 

  43. 43.

    Nikolay N. et al. Direct measurement of quantum efficiency of single-photon emitters in hexagonal boron nitride. Optica 6, 1084–1088 (2019).

  44. 44.

    Korona, T. & Chojecki, M. Exploring point defects in hexagonal boron-nitrogen monolayers. Int J. Quantum Chem. 119, e25925 (2019).

    Article  Google Scholar 

  45. 45.

    Cesar Jara T. R. et al. First-principles identification of single photon emitters based on carbon clusters in hexagonal boron nitride. Preprint at https://arxivorg/abs/200715990 (2020).

  46. 46.

    Frisch, M. J. et al. Gaussian 16 revision C.01 (Gaussian Inc., 2016).

Download references

Acknowledgements

We thank L. Bassett and A. Alkauskas for fruitful discussions. This work at Nottingham was supported by the Engineering and Physical Sciences Research Council (grant numbers EP/K040243/1, EP/P019080/1). We also thank the University of Nottingham Propulsion Futures Beacon for funding towards this research. We also acknowledge financial support from the Australian Research Council (via DP180100077, DE180100810, DP160104621 and DP190101058, CECE200100010) and the Asian Office of Aerospace Research & Development (FA9550-19-S-0003). Access to the epitaxial growth facilities is made possible through the Australian National Fabrication Facility, ACT Node. Ion implantation was performed at the Australian Facility for Advanced Ion Implantation Research (AFAiiR), RSP (ANU). This work was supported in part by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division under contract number DE-AC02-05-CH11231, within the sp2-Bonded Materials Program (KC2207), which provided for synthesis and structural characterization of hBN converted from carbon. The computational work was supported by National Computational Infrastructure (NCI), Intersect, the Shanghai University ICQMS high-performance computing facility and Chinese National Natural Science Foundation grant number 11674212. This work was supported in part by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy–EXC2147 ‘ct.qmat’ (project id 390858490).

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Contributions

N.M. and I.A designed the experiments. N.M., J.R.R., C.B. and I.A. wrote the manuscript with contributions from all co-authors. N.M. performed experimental measurements and data analysis. J.R.R. and M.J.F. performed the computational calculations. D.C., C.J. and H.H.T performed ion implantation and MOVPE growth. T.S.C., C.J.M., P.H.B. and S.V.N. performed MBE growth. H.L. and A.Z fabricated the HOPG to hBN conversion samples. A.G. and V.D. performed ODMR experiments. I.A., C.B. and M.T. supervised the project. All authors discussed the results and contributed to the manuscript.

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Correspondence to Igor Aharonovich.

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Peer review information Nature Materials thanks the anonymous reviewers for their contribution to the peer review of this work.

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Extended data

Extended Data Fig. 1 MOVPE hBN ensemble ZPL/PSB detuning.

a, An ensemble spectrum taken from MOVPE hBN (TEB 30) showing the energy separation between the ensemble of ZPLs to the resolved phonon sidebands. The detuning from the ZPL centroid at 2.122 eV to the LO1 phonon mode at 1.961 eV is 161 meV. While the detuning from the ZPL to the LO2 mode at 1.927 eV is 195 meV. b, An ensemble spectrum taken from a different confocal spot of the MOVPE hBN (TEB 30) sample where both the first and second order PSBs can be observed. The ZPL ensemble centroid is positioned at 2.116 eV, and the first PSB (which appears as a single peak due to the convolution of the LO1 and LO2 modes) is centered at 1.937 eV, a detuning of 179 meV. Additionally, a dimmer broad peak can be observed at lower energy spanning from roughly 1.789 eV to 1.725 eV, corresponding to the second order phonon modes which are comprised of three independent emissions, 2LO1, LO1 + LO2, and 2LO2. Source data

Extended Data Fig. 2 XPS C1s spectra from MOVPE hBN TEB series.

MOVPE hBN samples with increasing TEB flow. a, MOVPE hBN (TEB 10). b, MOVPE hBN (TEB 20). c, MOVPE hBN (TEB 30). d, MOVPE hBN (TEB 60). Source data

Extended Data Fig. 3 PL intensity of MOVPE hBN with increasing TEB flow vs the B-C + B-N Bonding %.

The integrated intensity of the ZPL peak from each MOVPE sample (as plotted in Fig. 1a) is plotted against the bonding percentage of C-B + C-N as determined by XPS. For TEB 10,20,30 we see an almost perfectly linear trend. For TEB 60 we observe a slightly reduced intensity increase, likely the result of non-radiative decay pathways induced by an increasingly defective material. Source data

Extended Data Fig. 4 Extraction of g value from room temperature ODMR (TEB 60).

ODMR resonance frequencies as a function of applied magnetic field, extracted from Fig. 1e. The data points are fit with equation S1 and yield an extracted g value of ~ 2.09. Source data

Extended Data Fig. 5 Temperature dependent ODMR of MOVPE (TEB 60) hBN.

We recorded the ODMR contrast from the highly carbon doped MOVPE (TEB 60) sample at four temperatures between 295-13 K. A similar FWHM of the resonance suggests the broadening is dominated by unresolved hyperfine interactions. Source data

Extended Data Fig. 6 Histograms of ZPL positions from various epitaxial sources.

a, 77 SPEs characterized in MOVPE hBN (TEB 10) display ZPLs clustered around 585 ± 10 nm. b, 248 SPEs characterized from CVD hBN on copper display ZPLs clustered around 580 ± 10 nm, reproduced with permission from ref. 28. c, 65 SPEs characterized in carbon doped MBE hBN on sapphire display ZPLs ranging across the visible spectrum. d, 26 SPEs characterized in undoped MBE hBN on silicon carbide displaying ZPLs ranging across the visible spectrum. Source data

Extended Data Fig. 7 ZPL FWHM comparison of SPEs located inside the C implanted region to as-grown single photon emitters in MOVPE hBN (TEB 10).

Blue triangles correspond to SPEs analyzed from as-grown MOVPE hBN (TEB 10). Red triangles correspond to SPEs located within the C implanted region of the same sample. The implantation created SPEs show a nearly 4 fold reduction in average linewidth. Source data

Extended Data Fig. 8 Spectra of MOVPE hBN (TEB 10) samples implanted with oxygen and silicon.

Implantations were done at a dose of 1013 cm−2 and an energy of 10 keV, using a TEM grid with 50 µm2 apertures as a mask. a, Typical spectra observed in the oxygen-implanted region pre-annealing, showing only background emission the VB- peak ~ 800 nm are observed. b, Characteristic spectrum from oxygen implanted region post annealing, where the only spectral signature observed is a broad peak at ~ 630 nm. c, Typical spectra observed in the silicon-implanted region pre-annealing, showing only background emission the VB- peak ~ 800 nm are observed. d, Characteristic spectrum from silicon implanted region post annealing, with the only spectral signature observed is a broad peak at ~ 630 nm. Source data

Extended Data Fig. 9 Wide-field imaging and spectral analysis of exfoliated hBN implanted with carbon prior to annealing.

The scale bar in each is 2 µm. a, Un-implanted exfoliated hBN reference sample. b, Exfoliated hBN implanted with carbon at a fluence of 1*1011ions/cm2. c, Exfoliated hBN implanted with carbon at a fluence of 1*1012ions/cm2. d, Exfoliated hBN implanted with carbon at a fluence of 1*1013ions/cm2. e, Exfoliated hBN implanted with carbon at a fluence of 1*1014ions/cm2. f-j samples were annealed at 1000 °C for 2 hours under vacuum (<1*106mbar). f, Un-implanted MOVPE hBN reference sample. g, MOVPE hBN implanted with carbon at a fluence of 1*1011ions/cm2. h, MOVPE hBN implanted with carbon at a fluence of 1*1012ions/cm2. i, MOVPE hBN implanted with carbon at a fluence of 1*1013ions/cm2. j, MOVPE hBN implanted with carbon at a fluence of 1*1014ions/cm2. Source data

Extended Data Fig. 10 Wide-field imaging and spectral analysis of MOVPE hBN implanted with carbon.

The scale bar in each is 2 µm. a, Un-implanted MOVPE hBN reference sample. b, MOVPE hBN implanted with carbon at a fluence of 1*1011ions/cm2. c, MOVPE hBN implanted with carbon at a fluence of 1*1012ions/cm2. d, MOVPE hBN implanted with carbon at a fluence of 1*1013ions/cm2. e, MOVPE hBN implanted with carbon at a fluence of 1*1014ions/cm2. f-j samples were annealed at 1000 °C for 2 hours under vacuum (<1*106mbar). f, Un-implanted MOVPE hBN reference sample. g, MOVPE hBN implanted with carbon at a fluence of 1*1011ions/cm2. h, MOVPE hBN implanted with carbon at a fluence of 1*1012 ions/cm2. i, MOVPE hBN implanted with carbon at a fluence of 1*1013ions/cm2. j, MOVPE hBN implanted with carbon at a fluence of 1*1014ions/cm2. Source data

Supplementary information

Supplementary Information

Supplementary Figs. 1–18, Tables 1–6, Discussion.

Computational Data 1

The normal modes, Duschinsky matrices and displacement vectors are provided for the spectral simulations shown in Fig. 5 .

Computational Data 2

Optimized Cartesian coordinates and basic characterization (including the lowest vibration frequencies when available).

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Mendelson, N., Chugh, D., Reimers, J.R. et al. Identifying carbon as the source of visible single-photon emission from hexagonal boron nitride. Nat. Mater. 20, 321–328 (2021). https://doi.org/10.1038/s41563-020-00850-y

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