InGaAsP/InP single photon avalanche diodes with ultra-high photon detection efficiency

We describe a planar front-illuminated InGaAsP/InP single-photon avalanche diode that is made in a separate absorption, grading, charge and multiplication heterostructure. By controlling the electric field in the center and periphery of the active area, the photoexcited carriers are mainly concentrated in the active area, especially in the center. Deep level defects are not obviously observed, and the dominated generation recommendation current and the trap assisted tunneling current are greatly suppressed. When operated in gated-mode, a photon detection efficiency (PDE) of 70% is achieved, with the DCR of 48 kHz at 226 K. And the afterpulse probability remains below 2.2% for PDEs up to 62.7%.