High quantum efficiency long-/long-wave dual-color type-Ⅱ InAs/GaSb infrared detector

A long-/long-wave dual-color detector with N-M-π-B-π-M-N structure was developed based on a type-Ⅱ InAs/GaSb superlattice. The saturated responsivity was achieved under low bias voltage for both channels. The device could be operated as a single detector for sequential detection and showed high quantum efficiencies. The peak quantum efficiencies of long-wavelength infrared band-1 (blue channel) and long-wavelength infrared band-2 (red channel) were 44% at 6.3 μm under 20 mV and 57% at 9.1 μm under -60 mV, respectively. The optical performance for each channel was achieved using a 2μm thickness absorber. Due to the high QE, the specific detectivities of the blue and red channels reached 5.0×10¹¹ cm·Hz^1/2/W at 6.8 μm and 3.1×10¹¹ cm·Hz^1/2/W at 9.1 μm, respectively, at 77 K.