Type-II superlattices base visible/extended short-wavelength infrared photodetectors with a bandstructure-engineered photo-generated carrier extractor

Visible/extended short-wavelength infrared photodetectors with a bandstructure-engineered photo-generated carrier extractor based on type-II InAs/AlSb/GaSb superlattices have been demonstrated. The photodetectors are designed to have a 100% cut-off wavelength of similar to 2.4 mu m at 300K, with sensitivity down to visible wavelengths. The photodetectors exhibit room-temperature (300K) peak responsivity of 0.6 A/W at similar to 1.7 mu m, corresponding to a quantum efficiency of 43% at zero bias under front-side illumination, without any anti-reflection coating where the visible cut-on wavelength of the devices is <0.5 mu m. With a dark current density of 5.3 x 10(-4) A/cm(2) under -20 mV applied bias at 300K, the photodetectors exhibit a specific detectivity of 4.72 x 10(10) cm.Hz(1/2)/W. At 150K, the photodetectors exhibit a dark current density of 1.8 x 10(-10) A/cm(2) and a quantum efficiency of 40%, resulting in a detectivity of 5.56 x 10(13) cm.Hz(1/2)/W.