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

Abstract

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 4.4μm, respectively, at 150K. The mid-wavelength channel exhibited a saturated quantum efficiency of 34% at 4μm under +200 mV bias voltage in a front-side illumination configuration and without any antireflection coating. At 200mV, the device exhibited a dark current density of 8.7×10-5 A/cm2 providing a specific detectivity of ∼2×1011 cm·Hz1/2/W at 150K. The short-wavelength channel achieved a saturated quantum efficiency of 20% at 1.8μm. 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·Hz1/2/W at 150K. The extended short-wavelength channel achieved a saturated quantum efficiency of 22% at 2.75μm. 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·Hz1/2/W at 150K.