CC BY
0Luminescence properties of single-photon sources in hexagonal
boron nitride flakes
A. Gritsienko1'2*, M. Pugachev1'2, A. Vitukhnovsky1'2, A. Kuntsevich1
1-P.N. Lebedev Physical Institute of the Russian Academy of Sciences, 53 Leninskiy Pr., 119991 Moscow,
Russia
2- Moscow Institute of Physics and Technology, National Research University, 9 Institutskn Per., 141700
Dolgoprudnyí, Russia
* grits_alex@rambler.ru
The appearance of emitters in hexagonal boron nitride (hBN) and their use as single photon sources has recently been actively discussed in the literature [1]. A hallmark of these emitters is their stable ultrahigh brightness at room temperature as well as their high internal and external quantum yields [2,3]. It has been found that these emitters have different spectral compositions, brightnesses, and photostabilities [4]. To date, there has been no understanding of the atomic structures of most of the emitters observed in hBN.
We report on the fabrication and optical characterization of emitters in hBN flakes, with a sub-nanosecond decay time. We find that bright emitters meet most of the criteria for quantum applications, including high purity and a rate of >1 GHz at the zero-phonon line. These emitters exhibit unusual photodynamics, switching between dark and bright states and possibly deactivating completely. The dynamics suggest the presence of an excited state close to the conduction band, indicating that possible electron escape to defects may be the main mechanism for deactivation.
We also studied homostructures consisting of two separate layers of hBN, in which microbubbles form spontaneously. Heat treatment of the obtained homostructures in an oxygen-rich medium led to the formation of single-photon emitters directly at the locations where bubbles formed. These emitters had high luminescence intensities, which did not degrade during optical measurements. The spectral response varied from emitter to emitter, with individual emitters having luminescence maxima in the range of 550-750 nm. Our results demonstrate that the formation of these emitters is linked to the presence of carbon compounds and local stresses in boron nitride.
The fabrication of photonic elements and their investigation was supported by the Russian Science Foundation project No. 22-19-00324. The technical support was partly financial from Ministry of Science and Higher Education of Russian Federation in the framework of Agreement #075-03-2024117/8 -May 23, 2024.
[1] J. Caldwell, I. Aharonovich, G. Cassabois, J. Edgar, B. Gil, D. Basov, Photonics with hexagonal boron nitride, Nature Reviews Materials, vol. 4, pp. 552-567, (2019).
[2] G. Grosso, H. Moon, B. Lienhard, S. Ali, D. Efetov, M. Furchi, P. Jarillo-Herrero, M. Ford, I. Aharonovich, D. Englund, Tunable and high-purity room temperature single-photon emission from atomic defects in hexagonal boron nitride, Nature Communications, vol. 8, p. 705, (2017).
[3] N. Nikolay, N. Mendelson, E. Özelci, B. Sontheimer, F. Böhm, G. Kewes, O. Benson, Direct measurement of quantum efficiency of single-photon emitters in hexagonal boron nitride. Optica, vol. 6, pp. 1084-1088, (2019).
[4] I. Aharonovich, J. Tetienne, M. Toth, Quantum emitters in hexagonal boron nitride, Nano Letters, vol. 22, pp. 9227-9235, (2022).
