Photophysics of GaN single-photon emitters in the visible spectral range

Abstract

In this work, we present a detailed photophysical analysis of recently-discovered optically stable, single photon emitters (SPEs) in Gallium Nitride (GaN). Temperature-resolved photoluminescence measurements reveal that the emission lines at 4 K are three orders of magnitude broader than the transform-limited widths expected from excited state lifetime measurements. The broadening is ascribed to ultra-fast spectral diffusion. Continuing the photophysics study on several emitters at room temperature (RT), a maximum average brightness of ~(427±215) kCounts/s is measured. Furthermore, by determining the decay rates of emitters undergoing three-level optical transitions, radiative and non-radiative lifetimes are calculated at RT. Finally, polarization measurements from 14 emitters are used to determine visibility as well as dipole orientation of defect systems within the GaN crystal. Our results underpin some of the fundamental properties of SPE in GaN both at cryogenic and RT, and define the benchmark for future work in GaN-based single-photon technologies. Figure 6. Room-temperature polarization spectroscopy of emitters in GaN. a) Absorption (green) and emission (red) polarization profiles from an emitter with a ZPL at 1.818 eV, exhibiting polarization visibilities of 34% and 79%, respectively. b) Polarization visibilities of 14 emitters showing that while the emitters are strongly polarized in emission, they show variable degrees of absorption polarization. c) Histogram of the difference in orientation between absorption and emission polarization.

Coherent Control of Nitrogen-Vacancy Center Spins in Silicon Carbide at Room Temperature

“…The red line is the fit of the data using double-exponential decay function. The fluorescence lifetime is about 2.1 ± 0.1 ns which is almost the same with the short excited state lifetimes τ1 [37,38]. The lifetime is much smaller than that of the divacancy in 4H-SiC [14,16,20,39], which is also consistent with the narrower gap of the g 2 (τ) function in Fig.…”

Suppression of spectral diffusion by anti-Stokes excitation of quantum emitters in hexagonal boron nitride

“…[5][6][7][8] The energy instability is detrimental to the coherence of the emitted photons, and thus to the quality of two-or multi-photon entanglementa prerequisite for many applications in quantum information science. [9][10] Spectral diffusion affects a vast majority of solid-state-based quantum emitters, including single molecules, 5 semiconductor quantum dots, 6 color centers in diamond, 11 gallium nitride, 12 zinc oxide, 13 rare-earth materials, 14 carbon nanotubes 15 and two-dimensional materials. 16 Approaches towards mitigating this undesired phenomenon include improving the purity of the host materials to minimize foreign defect sites, 11,[17][18] or employing active energy stabilization strategies [19][20] to induce a dynamic stark shift via external electric fields.…”

Manipulating Single‐Photon Emission from Point Defects in Diamond and Silicon Carbide

“…The nitrides (e.g., GaN and AlN), on the other hand, are more inclined to exhibiting narrow emission lines. For instance, room‐temperature single‐photon emission was demonstrated for both GaN [ 144,145 ] and wurtzite AlN films, [ 146 ] and tentatively assigned to nitrogen vacancy and divacancy complexes in the latter case. However, defect levels in AlN tend to occur too close to the band edges to facilitate single‐photon emission.…”