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

• VLWIR and LWIR interband cascade infrared photodetectors are grown and fabricated.
• High temperature operation of LWIR and VLWIR interband cascade infrared photodetectors is demonstrated.
• Characteristics of detectors in a wide temperature range are discussed.
• Bias-dependent behavior of these detectors is presented.

We report our recent studies of interband cascade infrared photodetectors (ICIPs) with 100% cutoff wavelengths of 16.0 μm and 9.2 μm 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 μm) were able to operate at higher temperatures (up to 250 K) with an extended cutoff wavelength of ∼12 μm. At 78 K, these LWIR detectors had a bias-independent photocurrent, with an R0A of 115 Ω cm2. This corresponded to a Johnson-noise-limited D∗ of 3.7 × 1010 cm Hz1/2/W at 8.0 μm.