Afterpulsing in Ge-on-Si Single-Photon Avalanche Diodes

Xin Yi, Zoë Greener, Fiona Fleming, Jarosław Kirdoda, Derek C. S. Dumas, Lisa Saalbach, Dave A. S. Muir, Lourdes Ferre-Llin, Ross W. Millar, Douglas J. Paul, Gerald Stuart Buller

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In this letter, we investigate afterpulsing in 26 and 100 μm diameter planar geometry Ge-on-Si single-photon avalanche diode (SPAD) detectors, by use of the double detector gating method with a gate width of 50 ns. Ge-on-Si SPADs were found to exhibit a 1% afterpulsing probability at a delay time of 200 μs and temperature of 78 K, and 130 μs at a temperature of 150 K. These delay times were measured with an excess bias of 3.5% applied, which corresponded to a single-photon detection efficiency of 15% at 1.31 μm. We demonstrate that reducing the detector diameter can also be an effective way to restrict afterpulsing in this material system.
Original languageEnglish
Pages (from-to)959-962
Number of pages4
JournalIEEE Photonics Technology Letters
Issue number17
Early online date26 Jun 2023
Publication statusPublished - 1 Sept 2023


  • Delays
  • Detectors
  • Ge-on-Si
  • Logic gates
  • Plasma temperature
  • Single-photon avalanche diode
  • Single-photon avalanche diodes
  • Temperature distribution
  • Temperature measurement
  • afterpulsing
  • photon counting
  • short-wave infrared
  • time-correlated single-photon counting

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering


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