abstract

• Defect centers in hexagonal boron nitride represent room-temperature single-photon sources in a layered van der Waals material. These light emitters appear with a wide range of transition energies ranging over the entire visible spectrum, which renders the identification of the underlying atomic structure challenging. In addition to their eminent properties as quantum light emitters, the coupling to phonons is remarkable. Their photoluminescence exhibits significant side band emission well separated from the zero phonon line (ZPL) and an asymmetric broadening of the ZPL itself. In this combined theoretical and experimental study we show that the phonon side bands can be well described in terms of the coupling to bulk longitudinal optical (LO) phonons. To describe the ZPL asymmetry we show that in addition to the coupling to longitudinal acoustic (LA) phonons also the coupling to local mode oscillations of the defect center with respect to the entire host crystal has to be considered. By studying the influence of the emitter%27s wave function dimensions on the phonon side bands we find reasonable values for the size of the wave function and the deformation potentials. We perform photoluminescence excitation measurements to demonstrate that the excitation of the emitters is most efficient by LO-phonon assisted absorption. © 2019 IOP Publishing Ltd.
• Defect centers in hexagonal boron nitride represent room-temperature single-photon sources in a layered van der Waals material. These light emitters appear with a wide range of transition energies ranging over the entire visible spectrum, which renders the identification of the underlying atomic structure challenging. In addition to their eminent properties as quantum light emitters, the coupling to phonons is remarkable. Their photoluminescence exhibits significant side band emission well separated from the zero phonon line (ZPL) and an asymmetric broadening of the ZPL itself. In this combined theoretical and experimental study we show that the phonon side bands can be well described in terms of the coupling to bulk longitudinal optical (LO) phonons. To describe the ZPL asymmetry we show that in addition to the coupling to longitudinal acoustic (LA) phonons also the coupling to local mode oscillations of the defect center with respect to the entire host crystal has to be considered. By studying the influence of the emitter's wave function dimensions on the phonon side bands we find reasonable values for the size of the wave function and the deformation potentials. We perform photoluminescence excitation measurements to demonstrate that the excitation of the emitters is most efficient by LO-phonon assisted absorption. © 2019 IOP Publishing Ltd.

authors

• Bratschitsch R.
• De Vasconcellos S.M.
• Del Pozo Zamudio Osvaldo
• Kern J.
• Khodaei Y.
• Kuhn T.
• Preuß J.A.
• Schmidt R.
• Schneider R.
• Sperling J.
• Steeger P.
• Tonndorf P.
• Wigger D.

publication date

• 2019-01-01

published in

• 2D Materials  Journal

keywords

• color center; hexagonal boron nitride; phonon coupling; single photon emitter; spectroscopy Boron nitride; Color centers; Crystal atomic structure; III-V semiconductors; Nitrides; Particle beams; Photoluminescence; Photons; Spectroscopy; Van der Waals forces; Wave functions; Asymmetric broadening; Hexagonal boron nitride; Longitudinal acoustic phonons; Longitudinal optical phonons; Phonon coupling; Photoluminescence excitation measurements; Quantum light emitters; Single photon emitters; Phonons

Digital Object Identifier (DOI)

• 10.1088/2053-1583/ab1188

start page

end page

volume

• 6

issue

• 3