skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Title: Photophysics of Intrinsic Single‐Photon Emitters in Silicon Nitride at Low Temperatures
Abstract A robust process for fabricating intrinsic single‐photon emitters in silicon nitride is recently established. These emitters show promise for quantum applications due to room‐temperature operation and monolithic integration with technologically mature silicon nitride photonics platforms. Here, the fundamental photophysical properties of these emitters are probed through measurements of optical transition wavelengths, linewidths, and photon antibunching as a function of temperature from 4.2 to 300 K. Important insight into the potential for lifetime‐limited linewidths is provided through measurements of inhomogeneous and temperature‐dependent broadening of the zero‐phonon lines. At 4.2 K, spectral diffusion is found to be the main broadening mechanism, while spectroscopy time series reveal zero‐phonon lines with instrument‐limited linewidths.  more » « less
Award ID(s):
2015025
PAR ID:
10472396
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Advanced Quantum Technologies
Volume:
6
Issue:
11
ISSN:
2511-9044
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. A robust process for fabricating intrinsic single-photon emitters in silicon nitride has been recently established. These emitters show promise for quantum applications due to room-temperature operation and monolithic integration with the technologically mature silicon nitride photonics platform. Here, the fundamental photophysical properties of these emitters are probed through measurements of optical transition wavelengths, linewidths, and photon antibunching as a function of temperature from 4.2K to 300K. Important insight into the potential for lifetime-limited linewidths is provided through measurements of inhomogeneous and temperature-dependent homogeneous broadening of the zero-phonon lines. At 4.2K, spectral diffusion was found to be the main broadening mechanism, while time-resolved spectroscopy measurements revealed homogeneously broadened zero-phonon lines with instrument-limited linewidths. 
    more » « less
  2. Color centers in wide bandgap semiconductors are attracting broad attention for use as platforms for quantum technologies relying on room-temperature single-photon emission (SPE), and for nanoscale metrology applications building on the centers’ response to electric and magnetic fields. Here, we demonstrate room-temperature SPE from defects in cubic boron nitride (cBN) nanocrystals, which we unambiguously assign to the cubic phase using spectrally resolved Raman imaging. These isolated spots show photoluminescence (PL) spectra with zero-phonon lines (ZPLs) within the visible region (496–700 nm) when subject to sub-bandgap laser excitation. Second-order autocorrelation of the emitted photons reveals antibunching withg2(0) ∼ 0.2, and a decay constant of 2.75 ns that is further confirmed through fluorescence lifetime measurements. The results presented herein prove the existence of optically addressable isolated quantum emitters originating from defects in cBN, making this material an interesting platform for opto-electronic devices and quantum applications. 
    more » « less
  3. Abstract Single-photon defect emitters (SPEs), especially those with magnetically and optically addressable spin states, in technologically mature wide bandgap semiconductors are attractive for realizing integrated platforms for quantum applications. Broadening of the zero phonon line (ZPL) caused by dephasing in solid state SPEs limits the indistinguishability of the emitted photons. Dephasing also limits the use of defect states in quantum information processing, sensing, and metrology. In most defect emitters, such as those in SiC and diamond, interaction with low-energy acoustic phonons determines the temperature dependence of the dephasing rate and the resulting broadening of the ZPL with the temperature obeys a power law. GaN hosts bright and stable single-photon emitters in the 600–700 nm wavelength range with strong ZPLs even at room temperature. In this work, we study the temperature dependence of the ZPL spectra of GaN SPEs integrated with solid immersion lenses with the goal of understanding the relevant dephasing mechanisms. At temperatures below ~ 50 K, the ZPL lineshape is found to be Gaussian and the ZPL linewidth is temperature independent and dominated by spectral diffusion. Above ~ 50 K, the linewidth increases monotonically with the temperature and the lineshape evolves into a Lorentzian. Quite remarkably, the temperature dependence of the linewidth does not follow a power law. We propose a model in which dephasing caused by absorption/emission of optical phonons in an elastic Raman process determines the temperature dependence of the lineshape and the linewidth. Our model explains the temperature dependence of the ZPL linewidth and lineshape in the entire 10–270 K temperature range explored in this work. The ~ 19 meV optical phonon energy extracted by fitting the model to the data matches remarkably well the ~ 18 meV zone center energy of the lowest optical phonon band ($$E_{2}(low)$$ E 2 ( l o w ) ) in GaN. Our work sheds light on the mechanisms responsible for linewidth broadening in GaN SPEs. Since a low energy optical phonon band ($$E_{2}(low)$$ E 2 ( l o w ) ) is a feature of most group III–V nitrides with a wurtzite crystal structure, including hBN and AlN, we expect our proposed mechanism to play an important role in defect emitters in these materials as well. 
    more » « less
  4. Solid-state single-photon emitters (SPEs) such as the bright, stable, room-temperature defects within hexagonal boron nitride (hBN) are of increasing interest for quantum information science. To date, the atomic and electronic origins of SPEs within hBN have not been well understood, and no studies have reported photochromism or explored cross correlations between hBN SPEs. Here, we combine irradiation time-dependent microphotoluminescence spectroscopy with two-color Hanbury Brown–Twiss interferometry in an investigation of the electronic structure of hBN defects. We identify evidence of photochromism in an hBN SPE that exhibits single-photon cross correlations and correlated changes in the intensity of its two zero-phonon lines. 
    more » « less
  5. We report on the generation of single-photon emitters in silicon nitride. We demonstrate monolithic integration of these quantum emitters with silicon nitride waveguides showing a room-temperature off-chip count-rate of ~104counts/s and clear antibunching behavior. 
    more » « less