Low dark current density extended short-wavelength infrared superlattice photodetector with atomic layer deposited Al 2 O 3 passivation

We report on a low dark current density P-B-i-N extended short-wavelength infrared photodetector with atomic layer deposited (ALD) Al 2 O 3 passivation based on a InAs/GaSb/AlSb superlattice. The dark current density of the Al 2 O 3 passivated device was reduced by 38% compared to the unpassivated device. The cutoff wavelength of the photodetector is 1.8 µm at 300 K. The photodetector exhibited a room-temperature (300 K) peak responsivity of 0.44 A/W at 1.52 µm, corresponding to a quantum efficiency of 35.8%. The photodetector exhibited a specific detectivity (D ∗ ) of 1.08×10 11 cm⋅Hz 1/2 /W with a low dark current density of 3.4×10 −5 A/cm 2 under −50mv bias at 300 K. The low dark current density Al 2 O 3 passivated device is expected to be used in the fabrication of extended short-wavelength infrared focal plane arrays for imaging.