Bias-selectable three-color short-, extended-short-, and mid-wavelength infrared photodetectors based on type-II InAs/GaSb/AlSb superlattices

A bias-selectable, high operating temperature, three-color short-, extended-short-, and mid-wavelength infrared photodetector based on InAs/GaSb/AlSb type-II superlattices on GaSb substrate has been demonstrated. The short-, extended-short-, and mid-wavelength channels' 50% cutoff wavelengths were 2.3, 2.9, and 4.4 μm, respectively, at 150 K. The mid-wavelength channel exhibited a saturated quantum efficiency of 34% at 4 μm under +200 mV bias voltage in a front-side illumination configuration and without any antireflection coating. At 200 mV, the device exhibited a dark current density of 8.7×10^-5 A/cm² providing a specific detectivity of ∼2×10¹¹ cm·Hz^1/2/W at 150 K. The short-wavelength channel achieved a saturated quantum efficiency of 20% at 1.8 μm. At -10 mV, the device's dark current density was 5.5×10^-8 A/cm². At zero bias, its specific detectivity was 1×10¹¹ cm·Hz^1/2/W at 150 K. The extended short-wavelength channel achieved a saturated quantum efficiency of 22% at 2.75 μm. Under -2 V bias voltage, the device exhibited a dark current density of 1.8×10^-6 A/cm² providing a specific detectivity of 6.3×10¹¹ cm·Hz^1/2/W at 150 K.