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Clarisse Fournier, Alexandre Plaud, Sébastien Roux, Aurélie Pierret, Michael Rosticher, [Kenji Watanabe](https://orcid.org/0000-0003-3701-8119), [Takashi Taniguchi](https://orcid.org/0000-0002-1467-3105), Stéphanie Buil, Xavier Quélin, Julien Barjon, Jean-Pierre Hermier, Aymeric Delteil

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[Position-controlled quantum emitters with reproducible emission wavelength in hexagonal boron nitride](https://mdr.nims.go.jp/datasets/3d3a00fd-2e84-4481-be37-0595745803e1)

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Position-controlled quantum emitters with reproducible emission wavelength in hexagonal boron nitrideARTICLEPosition-controlled quantum emitters withreproducible emission wavelength in hexagonalboron nitrideClarisse Fournier 1, Alexandre Plaud1, Sébastien Roux1, Aurélie Pierret2, Michael Rosticher2,Kenji Watanabe 3, Takashi Taniguchi 4, Stéphanie Buil1, Xavier Quélin1, Julien Barjon1,Jean-Pierre Hermier1 & Aymeric Delteil 1✉Single photon emitters (SPEs) in low-dimensional layered materials have recently gained alarge interest owing to the auspicious perspectives of integration and extreme miniaturizationoffered by this class of materials. However, accurate control of both the spatial location andthe emission wavelength of the quantum emitters is essentially lacking to date, thus hinderingfurther technological steps towards scalable quantum photonic devices. Here, we evidenceSPEs in high purity synthetic hexagonal boron nitride (hBN) that can be activated by anelectron beam at chosen locations. SPE ensembles are generated with a spatial accuracybetter than the cubed emission wavelength, thus opening the way to integration in opticalmicrostructures. Stable and bright single photon emission is subsequently observed in thevisible range up to room temperature upon non-resonant laser excitation. Moreover, the low-temperature emission wavelength is reproducible, with an ensemble distribution of width3 meV, a statistical dispersion that is more than one order of magnitude lower than thenarrowest wavelength spreads obtained in epitaxial hBN samples. Our findings constitute anessential step towards the realization of top-down integrated devices based on identicalquantum emitters in 2D materials.https://doi.org/10.1038/s41467-021-24019-6 OPEN1 Université Paris-Saclay, UVSQ, CNRS, GEMaC, Versailles, France. 2 Laboratoire de Physique de l’École Normale Supérieure, ENS, Université PSL, CNRS,Sorbonne Université, Université de Paris, Paris, France. 3 Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan.4 International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan. ✉email: aymeric.delteil@uvsq.frNATURE COMMUNICATIONS |         (2021) 12:3779 | https://doi.org/10.1038/s41467-021-24019-6 | www.nature.com/naturecommunications 11234567890():,;http://crossmark.crossref.org/dialog/?doi=10.1038/s41467-021-24019-6&domain=pdfhttp://crossmark.crossref.org/dialog/?doi=10.1038/s41467-021-24019-6&domain=pdfhttp://crossmark.crossref.org/dialog/?doi=10.1038/s41467-021-24019-6&domain=pdfhttp://crossmark.crossref.org/dialog/?doi=10.1038/s41467-021-24019-6&domain=pdfhttp://orcid.org/0000-0001-9642-581Xhttp://orcid.org/0000-0001-9642-581Xhttp://orcid.org/0000-0001-9642-581Xhttp://orcid.org/0000-0001-9642-581Xhttp://orcid.org/0000-0001-9642-581Xhttp://orcid.org/0000-0003-3701-8119http://orcid.org/0000-0003-3701-8119http://orcid.org/0000-0003-3701-8119http://orcid.org/0000-0003-3701-8119http://orcid.org/0000-0003-3701-8119http://orcid.org/0000-0002-1467-3105http://orcid.org/0000-0002-1467-3105http://orcid.org/0000-0002-1467-3105http://orcid.org/0000-0002-1467-3105http://orcid.org/0000-0002-1467-3105http://orcid.org/0000-0003-3914-3917http://orcid.org/0000-0003-3914-3917http://orcid.org/0000-0003-3914-3917http://orcid.org/0000-0003-3914-3917http://orcid.org/0000-0003-3914-3917mailto:aymeric.delteil@uvsq.frwww.nature.com/naturecommunicationswww.nature.com/naturecommunicationsThe technological control of van der Waals materials iscontinually expanding, motivated by the possibility ofrealizing increasingly complex hetero- and nanostructuresof minimal thickness. The considerable variety of impacted fieldsof physics1,2 has been including solid-state quantum optics3 sincethe discovery of single photon emission in WSe24–8 and hBN9. Inthe latter material, quantum emission is associated with pointdefects that were long thought to be of the intrinsic kind,although carbon impurities have been shown to play a role in thestructure of at least part of the observed SPEs10. Their emission isfound to be bright, stable11,12 and spectrally narrow13,14, andpersists up to room temperature and above15. They howeversuffer from large discrepancies between their emission wave-lengths, which are typically found between 550 and 850 nm16,17.Epitaxial hBN grown by chemical vapour epitaxy has beenrecently shown to lead to a narrowing of the spectral distributiondown to about 20 nm (75 meV) around a centre wavelength of585 nm10,18. Moreover, the SPEs appear in most cases at randomlocations in the crystal, although often preferentially close to theflake edges19. Effort towards controlling their position hasincluded the use of focused ion beam20, as well as strain throughexfoliation on patterned substrates21, but the emitters obtainedwith these methods exhibit large variations in their number,emission wavelength and optical properties. Moreover, the lattermethod results in limited possibilities of subsequent integration.In the 2D material MoS2, deterministic positioning with highprecision ( ~ 10 nm) has been achieved22,23 using He ion beam,but at the current stage the generated SPEs suffer from low countrates and large linewidths, which constitutes a major drawbackfor applications to photonic quantum information.Here, we demonstrate the activation of colour centres at chosenlocations using the electron beam of a commercial scanningelectron microscope (SEM). Electron irradiation has already beenshown to increase the formation probability of the SPEs16,19,24,but to date has never been the basis of a process that allows toactivate SPEs at preselected locations in hBN. We show that ourlocal irradiation process activates SPE ensembles with a sub-micrometric precision. The SPEs exhibit a strongly reducedensemble linewidth with respect to prior work on 2D materials.We investigate individual quantum emitters and demonstrateadvantageous photophysical properties, with in particular a highstability of both fluorescence intensity and centre wavelengthfluctuations. Our work paves the way to top-down fabrication ofintegrated devices based on SPEs in hBN.ResultsGeneration and characterization of SPE ensembles. We usehigh purity hBN synthesized at high pressure, high temperature(HPHT)25, of which we exfoliate single flakes of a few tens ofnanometres thickness on a silicon substrate, either with orwithout a top 285 nm SiO2 layer. The flakes are irradiated usingan electron beam of 15 keV acceleration voltage, under a cur-rent of 10 nA. We first focus on the sample with the SiO2epilayer, which we refer to as sample 1. For this sample, thebeam is adjusted to be about 33 nm diameter, to compromisebetween maximizing both the interaction cross-section and thelocalization accuracy. The irradiation time is fixed at 1000 s perirradiated spot. No additional treatment is performed on thesample. After the irradiation process, the sample is subse-quently characterized in photoluminescence (PL) in a confocalmicroscope, either at room temperature or at cryogenic tem-perature down to 5 K. The SPEs are non-resonantly excitedusing a laser at 405 nm, in pulsed or continuous wave regime.Figure 1a shows a SEM image of one of the irradiated flakes (ofthickness 60 nm), together with a low temperature (5 K)confocal fluorescence map of the irradiated zone (Fig. 1b).Emission from ensembles of colour centres is observed in allirradiated spots, within a radius close to that of the electronbeam (see Supplementary note 1) and thus showing that theemitters are localized in a volume of about 3.5 × 10−2 μm3 ≈0.4λ3, where λ ≈ 435 nm is the emission wavelength. The low-temperature spectra associated with the irradiated sites areshown Fig. 1c, d with two different resolutions. On the coarseresolution spectra (Fig. 1c; see also Supplementary note 2), theoverall common spectral shape of the SPEs can be observed:they exhibit a sharp zero-phonon line (ZPL) around 2.846 eV(435.7 nm) that concentrates about 40% of the light emission, aswell as an adjacent acoustic phonon sideband (45%) and twophonon replica, respectively red-shifted by 155 and 185 meV(15%). The high resolution spectra, centred around the ZPL, isshown Fig. 1d, where ensembles of discrete lines are observed.Keeping the above-mentioned irradiation parameters, we haveoverall realized 26 irradiation spots on 3 flakes. All of them gaverise to small ensembles of similar emission wavelength. Theensemble distribution, inferred from the PL spectra of all26 spots, has a full width at half maximum (FWHM) of 3 meV(see Supplementary note 3), which is an order of magnitudenarrower than the state of the art in 2D materials23. We esti-mate the number of emitters per site to be of order of a few tens,as confirmed by photon correlation measurements (see Sup-plementary note 4). Remarkably, no colour centre, neither at435 nm nor in the more usual wavelength range 550–850 nm,has been observed elsewhere on the flakes, although broademission can be measured near the edges or close to flakedefects. Interestingly, we note that light emission around 435nm has already been observed in hBN as reported by Shevitskiet al.26. In the latter work, however, blue emission could solelybe observed in cathodoluminescence and did neither respond tolaser excitation, nor exhibit any antibunching behaviour in thephoton statistics. Nonetheless, it is likely that the SPEs wereport here are of the same nature—we presume that, in ourcase, we are able to activate the response of the emitters tophotoluminescence owing to our electron irradiation para-meters being very different from those used in26, where theelectron irradiation dose is several orders of magnitude smaller.The necessity of a relatively high dose is compatible with thescenario of a dissociation of a pre-existing defect induced by theelectron beam, followed by a sufficient migration of the pro-duced species to lead to a stable optically active defect. We alsomention that our irradiation procedure did not lead to SPEactivation in other sources of hBN grown at atmosphericpressure (see Methods), consistently with Shevitski et al.26,suggesting a physical origin of the SPEs related either to theHPHT growth conditions or to the specific solvent precursorused during the hBN synthesis.Individual SPE photophysics. In order to investigate the indi-vidual properties of the colour centres, we have performedadditional irradiations on sample 2, with a reduced expositiontime (either 300 or 600 s) and a slightly larger electron beam (~1μm diameter) on a thinner flake (~30 nm thickness). The irra-diations yielded SPEs, some of which we could characterizeindividually (see Supplementary note 5). The emitted light iscollected by an air objective of NA 0.95, and detected usingavalanche photodiodes or a spectrometer (see Methods). Figure 2shows the typical room temperature photophysical properties of asingle representative colour centre, termed SPE1. The emissionspectrum (Fig. 2a) shows that the emission mainly occurs in aZPL centred at 440 nm, slightly red-shifted as compared with thelow temperature emission. The linewidth of the ZPL is 12 nm. AnARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-021-24019-62 NATURE COMMUNICATIONS |         (2021) 12:3779 | https://doi.org/10.1038/s41467-021-24019-6 | www.nature.com/naturecommunicationswww.nature.com/naturecommunicationsoptical phonon replica is visible around 465 nm. Figure 2b showsthe count rate as a function of the laser power. The emissionexhibits a saturation behaviour characteristic of two-level systems.We detect up to ~2.5 × 105 photons per second when the SPE isexcited above saturation. We fit the data with the standard powerdependence of a two-level system fluorescence I(P)= Isat/(1+Psat/P), yielding a saturation power of 3.7 mW and a saturationcount rate of 0.36MHz. This value is limited by the predominantemission of the SPE towards the high index absorptive siliconsubstrate and could be improved by a factor ~10 by collectingthrough a transparent substrate using an oil immersion objective,or by integrating the SPEs in a photonic structure. Figure 2cshows the emission polarization data of SPE1. The emission islinearly polarized, suggesting a single dipole transition linearlyoriented in the basal plane of the hBN crystal. We have per-formed second-order correlation measurements in pulsedregime to establish the quantum character of light emitted bySPE1. Figure 2d shows the results we obtained, with a value ofg(2)(0)= 0.12 ± 0.01 without background correction. This clearantibunching unequivocally demonstrates single photon emissionfrom the colour centre. The count rate is stable over time, as canbe observed on Fig. 2e, with no blinking or bleaching observed atFig. 1 Activation of localized ensembles of SPEs on a hBN flake. a SEM image of a high-purity hBN flake of about 15 × 20 μm and 60 nm thickness.b Confocal map of the irradiated zone (blue rectangle in a) with eight irradiation spots (orange dashed lines). (c) and (d) Low-temperature spectra of theeight spots with two different spectral resolutions, showing a reproducible ZPL within 0.7 nm.Fig. 2 Photophysical characterization of an individual SPE at room temperature. a Emission spectrum of SPE1, showing a main peak centred at 440 nm(ZPL) and a phonon replica at 465 nm. b Count rate as a function of the laser power in cw regime. The orange curve is a fit to the data, from which weextract a saturation power of 3.7 mW and a maximum photon detection rate of 3.6 × 105 Hz. c Count rate as a function of the angle of a polarizer placedbefore the detector, showing linearly polarized emission. The orange curve is a sine fit of the data. d Photon correlations in pulsed regime measured with315 μW excitation power and 80MHz repetition rate, yielding g(2)(0) = 0.12 ± 0.01 and thus demonstrating single photon emission. Inset: period-wiseintegrated coincidences (error bars: 1 standard deviation). The dashed orange line denotes the classical limit. e Time trace of the photon detection rate with100 ms binning, calculated from the same raw data as (d). f Fluorescence decay in logarithmic scale, extracted from the same raw data as (d). The orangecurve is an exponential fit to the data, yielding τ= 1.85 ns.NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-021-24019-6 ARTICLENATURE COMMUNICATIONS |         (2021) 12:3779 | https://doi.org/10.1038/s41467-021-24019-6 | www.nature.com/naturecommunications 3www.nature.com/naturecommunicationswww.nature.com/naturecommunicationstimescales ≥1 ms. The absence of blinking at shorter timescales isensured by second order correlations at intermediate timescales(see Supplementary note 7). Finally, Fig. 2f shows a fluorescencedecay measurement, together with an exponential fit of the data.The lifetime of the excited state is found to be 1.85 ns, of the sameorder of magnitude as other families of SPEs in hBN.Statistical dispersion of individual SPE properties at roomtemperature. We have performed similar measurements on 10SPEs on two flakes (labelled SPE1 to SPE10). Figure 3 shows thestatistical dispersion of the associated physical quantities. Thevalue of g(2)(0) (without background correction) is found between0.1 and 0.25, as shown Fig. 3a, mainly limited by fluorescencebackground and emission from nearby SPEs. Figure 3b shows thestatistical spread of the fluorescence lifetime, which is centredaround 1.87 ns with a standard deviation of 0.14 ns. Finally, thepolarization angle of the emission from 6 SPEs on the same flake,to ensure a common crystalline orientation, is shown Fig. 3c.Although their directions seem correlated, they do not coincidewith crystal axes. Additionally, we note that we did not observeany measurable variation of the ZPL wavelength at room tem-perature. These results show that the irradiation process yieldsSPEs with considerably homogeneous properties.Low-temperature spectroscopy of individual SPEs. The spectralproperties of individual SPEs at low temperature have been fur-ther investigated, and are depicted Fig. 4. For most SPEs, the ZPLlinewidth appears to be limited by our spectrometer resolution(~150 μeV), which is the case for SPE1 as shown Fig. 4a. Bymeasuring the emission spectrum as a function of time, we areable to observe the spectral diffusion of the ZPL. Figure 4b showsthe result in the case of SPE1. We can observe fluctuations of thecentre wavelength at timescales of a few seconds, with a standarddeviation of 45 μeV. The spectral diffusion of other SPEs is shownFig. 4c and d. The standard deviation of the line positions overtime typically lies in the range 10 to 50 μeV (2.5 to 12 GHz),although some SPEs with larger fluctuations (a few 100 s of μeV)have also been encountered. These values are in the very lowrange of values usually observed for SPEs in hBN under non-resonant excitation, and could be further improved using reso-nant excitation14,27. The spectral diffusion, attributed to chargefluctuations in the close environment of the defect, suggests thatthe emission is sensitive to static electric field, thus opening theway to dc-Stark tuning of the emission line using, for instance,graphene electrodes28. Given the natural spectral proximity of theemission from different SPEs, the possibility to electrically tunethe emission wavelength could potentially allow to bring any pairof SPEs to resonance, enabling quantum interference of photonsemitted by distinct SPEs.DiscussionIn summary, we have demonstrated the possibility to activateSPEs in high-purity hBN at deterministic locations using theelectron beam of a commercial SEM. This accessible process iswell adapted to potential large-scale or industrial applications.The photophysical properties of the SPEs are advantageous andsubstantially replicable. In particular, the reproducibility of theemission line has no equivalent in 2D materials, and couldopen the way to quantum interference between distinct emit-ters. The relatively short emission wavelength opens the way tominiaturized on-chip applications, while still lying in thetechnology-friendly visible range. At low temperature, thespectral mismatch between the ZPL and the acoustic phononsideband opens the way to the demonstration of indis-tinguishable photon emission by filtering out the incoherentcontribution. However, while we have shown that antibunchingpersists up to room temperature, the emission becomes inco-herent. Therefore, demonstration of room-temperature photonindistinguishability would imply to reach non-trivial cavityquantum electrodynamics regimes29,30 that would entail anaccurate coupling of the SPEs to a microcavity. Our workbrings fundamental questions on the precise nature of thecolour centres and on the physical mechanism that rendersthem optically active upon electron irradiation, that willmotivate both further experimental investigations and theore-tical studies. On the technological side, it will be desirable tosettle methods allowing to deterministically obtain a single SPEper irradiation spot. Such process could for instance make useof in-situ cathodoluminescence measurements31 during theirradiation process, heralding successful activation of a colourcentre. This could in turn enable deterministic coupling ofindividual SPEs to photonic32 or plasmonic33 nanostructures.We expect our research to bring new possibilities to the field ofquantum optics in 2D materials, that could yield applicationsin nanophotonics, integrated quantum optics, and quantuminformation science.MethodsSample fabrication. High-purity hBN was grown under high pressure/hightemperature using barium boron nitride (Ba3B2N4) as a solvent system. TheFig. 3 Statistical dispersion of individual SPE properties. a g(2)(0) of 10SPEs, showing single-photon emission. b Fluorescence lifetime τ of thesame 10 individual SPEs, with a mean value of 1.87 ns. c Polarization axis ofthe emission of 6 individual SPEs on the same flake, showing that mostSPEs emit with a similar polarization direction.ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-021-24019-64 NATURE COMMUNICATIONS |         (2021) 12:3779 | https://doi.org/10.1038/s41467-021-24019-6 | www.nature.com/naturecommunicationswww.nature.com/naturecommunicationshBN flakes were obtained by mechanical exfoliation of bulk material oncommercial silicon substrates. We used two different exfoliation methods forthe two samples: for sample 1, the hBN has been exfoliated using two 3 mmthick polydimethylsiloxane (PDMS) stamps on a SiO2/Si substrate (with 285nm SiO2 epilayer), and for sample 2 we used Scotch tape to exfoliate on a Sisubstrate. This allows to rule out the role of a specific residue in the SPEcreation process. Prior to the exfoliation, the substrates were cleaned usingacetone for 5 min, isopropyl alcohol for 5 min, followed by 5 min of 30 Woxygen plasma treatment. Two control samples grown at atmospheric pressurehave also been used: a APHT (atmospheric pressure, high temperature) samplegrown in KSU (Kansas, USA) using Ni/Cr solvent34, and a sample grown inLMI (Lyon, France) using PDC (polymer derived ceramics)35. Both sampleshave been exfoliated using adhesive tape on a SiO2/Si substrate. The SEMimaging and the electron irradiations were performed in a commercial SEM(JEOL 7001F). The flake thicknesses were measured with an atomic forcemicroscope.Optical characterization. For room temperature characterization, the sample wasplaced in a confocal microscope with an air objective of NA 0.95. Low-temperaturecharacterization was done in a closed-cycle cryostat and a low-T objective of NA0.8 was used. In both cases, the sample was placed on three-axis piezo positioners.A 405 nm laser diode was used to excite the SPEs, either in continuous wave or inpulsed regime (pulse length ~200 ps, repetition rate 80MHz). A dichroic mirror(cutoff wavelength 414 nm) and a fluorescence filter allowed to suppress back-reflected laser light. The signal was fibre-coupled to either a grating spectrometer(Princeton Instruments) or avalanche photodiodes (Micro Photon Devices) with30% collection efficiency in the relevant wavelength range, and the detection eventwas recorded using a time-tagged single photon counting module (PicoQuant). Inthe photon correlations measurements, only the photons emitted after the laserpulse have been recorded in order to avoid double excitation events caused by thefinite laser pulselength.Data availabilityThe data generated in this study are available at https://doi.org/10.5281/zenodo.4768457.Received: 18 May 2021; Accepted: 27 May 2021;References1. Novoselov, K. 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The standard deviation of the centre wavelength over time is found to be 45 μeV, as determinedby Lorentzian fits of the data. c Spectral diffusion of another SPE (SPE2) and d spectral diffusion of an ensemble of three SPEs, with uncorrelatedfluctuations of different magnitudes. All SPEs are excited with 1 mW cw laser light at 405 nm.NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-021-24019-6 ARTICLENATURE COMMUNICATIONS |         (2021) 12:3779 | https://doi.org/10.1038/s41467-021-24019-6 | www.nature.com/naturecommunications 5https://doi.org/10.5281/zenodo.4768457www.nature.com/naturecommunicationswww.nature.com/naturecommunications13. Li, X. et al. Nonmagnetic quantum emitters in boron nitride with ultranarrowand sideband-free emission spectra. ACS Nano 11, 6652–6660 (2017).14. Dietrich, A. et al. Observation of Fourier transform limited lines in hexagonalboron nitride. Phys. rev. B 98, 081414(R) (2018).15. Kianinia, M. et al. 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Deep ultraviolet light-emitting hexagonal boron nitride synthesized at atmospheric pressure. Science317, 932 (2007).35. Matsoso, B. et al. Synthesis of hexagonal boron nitride 2D layers using polymerderived ceramics route and derivatives. J. Phys. Mater. 3, 034002 (2020).AcknowledgementsWe acknowledge many useful discussions with Christophe Arnold. We thank BrunoBerini for atomic force microscope measurements and Christèle Vilar for technicalsupport on electron microscopy. This work is supported by funding from the FrenchInstitute of Physics (INP), and from the French national research agency (ANR) undergrant agreement No ANR-14-CE08-0018 (GoBN: Graphene on Boron Nitride Tech-nology). This work also received funding from the European Union’s Horizon 2020research and innovation program under Grant Nos. 785219 (Graphene Flagship Core 2)and 881603 (Graphene Flagship Core 3). K.W. and T.T. acknowledge support from theElemental Strategy Initiative conducted by the MEXT, Japan, Grant No.JPMXP0112101001, JSPS KAKENHI Grant No. JP20H00354 and the CREST(JPMJCR15F3), JST.Author contributionsK.W. and T.T. grew the hBN. Al.P. and J.B. discovered the SPEs in cathodoluminescence.Au.P. and M.R. fabricated the samples. Al.P., S.R., and J.B. designed the irradiationprotocol and performed the irradiations. C.F. and A.D. performed the optical mea-surements. S.B., X.Q., J.P.H., and A.D. designed the optical experiments and discussedthe data. A.D. supervised the project and wrote the paper, with input from all of us.Competing interestsThe authors declare no competing interests.Additional informationSupplementary information The online version contains supplementary materialavailable at https://doi.org/10.1038/s41467-021-24019-6.Correspondence and requests for materials should be addressed to A.D.Peer review informationNature Communications thanks the anonymous reviewers fortheir contribution to the peer review of this work.Reprints and permission information is available at http://www.nature.com/reprintsPublisher’s note Springer Nature remains neutral with regard to jurisdictional claims inpublished maps and institutional affiliations.Open Access This article is licensed under a Creative CommonsAttribution 4.0 International License, which permits use, sharing,adaptation, distribution and reproduction in any medium or format, as long as you giveappropriate credit to the original author(s) and the source, provide a link to the CreativeCommons license, and indicate if changes were made. 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To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.© The Author(s) 2021ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-021-24019-66 NATURE COMMUNICATIONS |         (2021) 12:3779 | https://doi.org/10.1038/s41467-021-24019-6 | www.nature.com/naturecommunicationshttps://doi.org/10.1038/s41467-021-24019-6http://www.nature.com/reprintshttp://creativecommons.org/licenses/by/4.0/http://creativecommons.org/licenses/by/4.0/www.nature.com/naturecommunications Position-controlled quantum emitters with reproducible emission wavelength in hexagonal boron nitride Results Generation and characterization of SPE ensembles Individual SPE photophysics Statistical dispersion of individual SPE properties at room temperature Low-temperature spectroscopy of individual SPEs Discussion Methods Sample fabrication Optical characterization Data availability References Acknowledgements Author contributions Competing interests Additional information