Enhanced responsivity and detectivity values of short 30-period InAs/GaSb type-II infrared photodetectors with reduced device areas

Abstract Enhanced responsivity and detectivity values are observed for a short 30-period InAs/GaSb type-II superlattice infrared photodetector with reduced device areas. With cut-off wavelength at 4 µm, the device with the smallest device area exhibits the highest 10 K responsivity value of 15 mA/W and the corresponding detectivity value of 1.9 × 10 10 cm·Hz 1/2 /W at 3.6 µm. The phenomenon is attributed to the increasing carrier recombination processes with increasing transport paths for photo-excited carriers with increasing device areas. The thermal images obtained by using a single-detector raster scan system have demonstrated the potential of the device for this application.