High-performance short-wavelength infrared photodetectors based on type-II InAs/InAs1-xSbx/AlAs1−xSbx superlattices

A high-performance short-wavelength infrared n-i-p photodiode based on InAs/InAs1−xSbx/AlAs1−xSbx type-II superlattices on GaSb substrate has been demonstrated. The device is designed to have a 50% cut-off wavelength of ∼1.8 μm at 300 K. The photodetector exhibited a room-temperature (300 K) peak responsivity of 0.47 A/W at 1.6 μm, corresponding to a quantum efficiency of 37% at zero bias under front-side illumination, without any anti-reflection coating. With an R × A of 285 Ω cm2 and a dark current density of 9.6 × 10−5 A/cm2 under −50 mV applied bias at 300 K, the photodiode exhibited a specific detectivity of 6.45 × 1010 cm Hz1/2/W. At 200 K, the photodiode exhibited a dark current density of 1.3 × 10−8 A/cm2 and a quantum efficiency of 36%, resulting in a detectivity of 5.66 × 1012 cm Hz1/2/W.