Extended short-wavelength infrared nBn photodetectors based on type-Ⅱ InAs/AISb/GaSb superlattices with an AlAsSb/GaSb superlattice barrier

摘要

Extended short-wavelength infrared nBn photodetectors based on type-Ⅱ InAs/AISb/GaSb superlattices on GaSb substrate have been demonstrated. An AlAs_(0.10)Sb_0.90)/GaSb H-structure superlattice design was used as the large-bandgap electron-barrier in these photodetectors. The photodetector is designed to have a 100% cut-off wavelength of ~2.8 μm at 300 K. The photodetector exhibited a room-temperature (300 K) peak responsivity of 0.65 A/W at 1.9 μm, corresponding to a quantum efficiency of 41% at zero bias under front-side illumination, without any anti-reflection coating. With an R x A of 78 Q cm~2 and a dark current density of 8 x 10~(-3) A/cm~2 under -400 mV applied bias at 300K, the nBn photodetector exhibited a specific detectivity of 1.51 x 10~(10)cm Hz~(1/2)/W. At 150 K, the photodetector exhibited a dark current density of 9.5 x 10 ~(-9) A/cm~2 and a quantum efficiency of 50%, resulting in a detectivity of 1.12 x 10~(-13) cm·Hz~(1/2)/W.