Ge-on-Si Single-Photon Avalanche Diode Detectors with Low Noise Equivalent Power in the Short-Wave Infrared

Single-Photon Avalanche Diode (SPAD) detectors are of significant interest for a range of applications [1] , in particular for quantum technologies (e.g. quantum-key distribution, quantum information processing), and light detection and ranging (LIDAR) for defence, terrain mapping, and autonomous vehicles. These applications either require, or benefit from, operation at wavelengths in the short-wave infrared (SWIR). Previous SWIR single-photon LIDAR has typically used InGaAs/InP SPAD detector technology, which has relatively low efficiency and suffers from afterpulsing. Previously, a pseudo-planar design for a Ge-on-Si SPAD was demonstrated [2] , yielding a huge improvement in performance for Ge-on-Si SPADs at 1310 nm and demonstrating the potential for Si foundry compatible SWIR SPADs. Furthermore, reduced afterpulsing was demonstrated compared to a commercial InGaAs/InP device when measured in nominally identical conditions. Here we present a further step change in performance, with reduced dark count rate (DCR), record low noise-equivalent-power (NEP) and low jitter by scaling the technology and developing 26 µm diameter pixels [3]