Single photon avalanche diodes (SPADs) for 1.5 μm photon counting applications

The paper reports on the design and characterization of InGaAs/InP single photon avalanche diodes (SPADs) for photon counting applications at wavelengths near 1.5 µm. It is shown how lower internal electric field amplitudes can lead to reduced dark count rates, but at the expense of degraded afterpulsing behaviour and larger timing jitter. Dark count rate behaviour provides evidence of thermally assisted tunnelling with an average thermal activation energy of ∼0.14 eV between 150 K and 220 K. Afterpulsing behaviour exhibits a structure-dependent afterpulsing activation energy, which quantifies how carrier de-trapping varies with temperature. SPAD performance simultaneously exhibits a dark count rate of 10 kHz at a detection efficiency of 20% with timing jitter of 100 ps at 200 K, and with appropriate performance tradeoffs, we demonstrate a 200 K dark count rate as low as 3 kHz, a detection efficiency as high as 45%, and a timing jitter as low as 30 ps.