Single-photon avalanche diode

Quantum mechanics

Avalanche diode

Detector

Voltage

Photodetector

Materials science

Infrared

Planar

Computer graphics (images)

Germanium

Computer science

Silicon

Semiconductor

Wavelength

Picosecond

Breakdown voltage

Diode

Photon

Avalanche photodiode

Laser

Physics

Optics

Optoelectronics

Nature Communications

Single-photon detection has emerged as a method of choice for ultra-sensitive measurements of picosecond optical transients. In the short-wave infrared, semiconductor-based single-photon detectors typically exhibit relatively poor performance compared with all-silicon devices operating at shorter wavelengths. Here we show a new generation of planar germanium-on-silicon (Ge-on-Si) single-photon avalanche diode (SPAD) detectors for short-wave infrared operation. This planar geometry has enabled a significant step-change in performance, demonstrating single-photon detection efficiency of 38% at 125 K at a wavelength of 1310 nm, and a fifty-fold improvement in noise equivalent power compared with optimised mesa geometry SPADs. In comparison with InGaAs/InP devices, Ge-on-Si SPADs exhibit considerably reduced afterpulsing effects. These results, utilising the inexpensive Ge-on-Si platform, provide a route towards large arrays of efficient, high data rate Ge-on-Si SPADs for use in eye-safe automotive LIDAR and future quantum technology applications.

High performance planar germanium-on-silicon single-photon avalanche diode detectors