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The performances of wavelength-extended In0.83Ga0.17As PIN photodetectors with 8 × 1015 or 4 × 1016 cm−3 doped absorption layers were investigated and compared at different temperatures and bias voltages. Results displayed that they showed comparable device performance around room temperature and low bias voltages, but relatively large difference at lower temperatures and higher bias voltages. At lower operation temperatures the In0.83Ga0.17As photodetectors with 8 × 1015 cm−3 doped absorption layers showed smaller dark currents and higher resistance area products R0A than those with 4 × 1016 cm−3 doped absorption layers. It was ascribed to the reduced trap-assisted tunneling dark current in the photodetector with the lower doped In0.83Ga0.17As absorber layer.

InP-based InGaAsP photodetectors targeting on 1.06 μm wavelength detection have been grown by gas source molecular beam epitaxy and demonstrated. For the detector with 200 μm mesa diameter, the dark current at 10 mV reverse bias and R 0 A are 8.89 pA (2.2 × 10 −8 A/cm 2 ) and 3.9 × 10 5 Ω cm 2 at room temperature. The responsivity and detectivity of the InGaAsP detector are 0.30 A/W and 1.45 × 10 12 cm Hz 1/2 W −1 at 1.06 μm wavelength. Comparing to the reference In 0.53 Ga 0.47 As detector, the dark current of this InGaAsP detector is about 570 times lower and the detectivity is more than ten times higher, which agrees well with the theoretical estimation.