hBN Quantum Defect Engineering record

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NanoLet2016_Bright UV Single Photon Emission

  • Cathodoluminescence, electron injection
    • hyper-spectral imaging
    • sample on holely carbon film (for TEM?)

hBN exhibits potential for optoelectronic applications by its strong, stable, room-temperature UV emission.

Hyper-spectral cathodoluminescence imaging showed the composition of the CL spectrum

  • a boardband signal centered at 3.9 eV
  • a series of sharp lines
    • constant energy separation of about 180meV
    • ascribed to a 4.09 eV zero phonon line followed by LO-TO phonon replica
    • faint shuolders 70meV below each major line
      • addtioanl ZO phonon modes
  • Gaussians peak fitting

two main characters:

  • boardband signal at 3.9eV
    • highly localized spots of ~80nm
    • by TRPL, energy resolved PL
      • long lifetime
      • multiple decay behavior
      • donor-accpetor pairs recombination
      • intrinsic defects can be generated by electron irradiation
    • being background in $g^{(2)}(\tau)$
  • 4.09 eV major peak
    • point defect, by electron irradiation
    • associated with a carbon substitional impurity at a nitrogen site $C_N$
    • recomination mechanism unknown
    • TRPL 1.1 ns range lifetime
    • only this signal have high antibunching properties

highly localized illumination is achevied by performing HBT in a STEM+CL setup, to maximize the signal-to-background ratio (SBR). Furthermore, by subtracting the contribution from the broadband background effective photon emission, higher SBR and lower $g^{(2)}(\tau)$ was obtained.

NMater2021_Identifying carbon as the source of visible

  • test synthesis methods of hBN, intrinsic defects
    • metal-organic vapour-phase epitaxy, with varying flow rate of triethylboron (TEB, precursor)
    • high temperature MBE on sapphire
    • high temperature MBE on SiC
    • conversion of highly oriented pyrolytic graphite (HOPG) into hBN

  • ion implantation

  • peak positions
    • 585, 635 nm
    • at different sample location
  • zero phonon line (ZPL) at 585 nm is epitaxy

  • phonon sideband (PSB) peak is 176meV

  • ion implantation
    • defect creation
    • major attempt: carbon, tried: silicon, oxygen
    • pink region I: carbon implantation
      • second order correlation showed antibunching
      • most emitters 80% from ZPL peaks (585 nm)
        • narrow ZPL line, minimal phonon coupling (by computation)
      • PSB peaks almost disappeared
      • 20% SPEs diskplay similar line shapes and phonon coupling to the pre-existing SPEs in MOVPE sample
    • darker pink region II: masked, no implantation
      • masked as reference, spectrum same as MOVPE sample
      • also anitbunching
    • after annealinga in high vacuum and high temperature
      • ion scattering around the mask edges and vacancy diffusion
      • line shape characteristic of ZPL in the implanted region passed out
        • about $g^{(2)}(\tau) \approx 1$, coherent state?
      • implanted, diffused, and masked region showed similar spectrum
        • diffused region not that quantum
        • not too much variation in masked region of second order autocorrelation
  • DFT calculation
    • need time to take a look
      • phonon coupling
      • emission
      • structural

ACSApplMaterInter2016_Engineering and Localization of Quantum Emitters

  • test defect forming techniques, for large hBN layers
    • ion implantation
      • B
      • BN
      • O
      • Si
    • 515nm 230fs 1 pulse
    • electron beam 15keV

      Ultrashort laser pulses are efficient sources of free-electron acceleration because of their high peak intensities. Free electrons accelerated to energies greater than the band gap are efficient in forming defect and breaking chemical bonds. Color center formation in dielectric materials is typical under femtosecond-laser irradiation at such fluences/irradiances.

  • free electrons accelerated to energies greater than the band gap
  • defect forming
  • breaking chemical bonds
  • femtosecond laser pulse
  • full polarization behavior
  • didnt come up with any information of the defect classification

Creation and repair of luminescence defects in hexagonal boron nitride by irradiation and annealing for optical neutron detection

A quantum coherent spin in hexagonal boron nitride at ambient conditions

Atomic and Electronic Structure of Defects in hBN: Enhancing Single-Defect Functionalities