Interband cascade infrared photodetectors with long and very-long cutoff wavelengths

We report our recent studies of interband cascade infrared photodetectors (ICIPs) with 100% cutoff wavelengths of 16.0 mu m and 9.2 mu m at 78 K. The very-long-wavelength infrared (VLWIR) detectors were able to operate at temperatures up to 143 K. Relatively high dark current densities were observed from these VLWIR detectors. This was attributed to the very narrow bandgap and possibly to defects in the materials. In addition, the photo-response of these detectors was strongly dependent on bias, indicating that further research and device optimization are necessary. Two-stage ICIPs in the long-wavelength infrared (LWIR) spectrum (8-12 mu m) were able to operate at higher temperatures (up to 250 K) with an extended cutoff wavelength of 12 mu m. At 78 K, these LWIR detectors had a bias-independent photocurrent, with an R(0)A of 115 Omega cm(2). This corresponded to a Johnson-noise-limited D* of 3.7 x 1(10) cm Hz(1/2)/W at 8.0 mu m. (C) 2014 Elsevier B.V. All rights reserved.