Long wavelength interband cascade photodetector with type II InAs/GaSb superlattice absorber
Shaolong Yan, Jianliang Huang, Ting Xue, Yanhua Zhang, Wenquan Ma
Abstract
Abstract We report on a long wavelength interband cascade photodetector with type II InAs/GaSb superlattice absorber. The device is a three-stage interband cascade structure. At 77 K, the 50% cutoff wavelength of the detector is 8.48 μ m and the peak photoresponse wavelength is 7.78 μ m. The peak responsivity is 0.93 A/W and the detectivity D * is 1.12 × 10 11 cm·Hz 0.5 /W for 7.78 μ m at –0.20 V. The detector can operate up to about 260 K. At 260 K, the 50% cutoff wavelength is 11.52 μ m, the peak responsivity is 0.78 A/W and the D * is 5.02 × 10 8 cm·Hz 0.5 /W for the peak wavelength of 10.39 μ m at –2.75 V. The dark current of the device is dominated by the diffusion current under both a small bias voltage of –0.2 V and a large one of –2.75 V for the temperature range of 120 to 260 K.