A comparative study of front- and back-illuminated planar InGaAs/InP avalanche photodiodes

Abstract In this work, a planar In0.53Ga0.47As/InP avalanche photodiode (APD) working in both front- and back-illumination modes is fabricated for a comparative study. The great differences in the electrical and spectral performances between the two operating approaches can be originated from the PIN junction in the InP cap layer with high electric field, which plays the role of short-wavelength photoelectric conversion before the InP multiplication layer punches through under front-illumination.