Dependence of dark current on carrier lifetime for InGaAs/InP avalanche photodiodes

Abstract

Effects of carrier lifetime of all layers on the dark current have been studied for the separate-absorption-grading-charge-multiplication InGaAs/InP avalanche photodiodes (APDs). The results indicate that the remarkably increasing of the dark current at the punch-through voltage strongly depends on the carrier lifetime of InGaAs absorption layer. According to the simulation results, we can estimate the carrier lifetime of InGaAs absorption layer and InP multiplication layer to be about 100 ns and 20 ps for our fabricated device. And we can see that the dark current of APDs near the breakdown voltage is mainly dominated by the thermal generation–recombination current from the InGaAs absorption layer and trap-assisted-tunneling current from the InP multiplication layer.