Characteristics of non-annealed λ = 1.35 μm closely lattice-matched GaInNAs/GaAs p-i-n photodetector structures grown by solid-source molecular beam epitaxy

The electrical and optical characteristics of planar non-annealed GaInNAs/GaAs p-i-n photodetector structures with 0.5 μm thick GaInNAs i-layer with nitrogen composition higher than 3% and detection wavelength up to 1.35 μm are reported. Soft-breakdown behavior in the reverse biased characteristic was observed under non-illuminated condition. Analysis of the reverse biased current dependence on detector diameter under non-illuminated condition shows a more significant contribution from the bulk generation current compared to surface recombination current. Under forward bias, the ideality factor value of 1.35 is found to be temperature independent. This suggests that the recombination current in the depletion region contributes significantly to the forward biased current besides the diffusion current. Low-temperature (4 K) photoluminescence (PL) from the GaInNAs layer shows an emission peak at λ = 1.29 μm. From curve fitting of the photoresponsivity spectrum, the room-temperature bandgap of Eg,RT = 0.92 eV (or λ = 1.35 μm) is deduced. The room-temperature photoresponsivity spectrum shows a broad wavelength detection range of up to λ = 1.4 μm.