19 September 2013 Hetero-engineering infrared detectors with type-II superlattices
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InAs/GaSb type-II superlattices (T2-SLs) are of great interest as they provide a lot of band engineering flexibility. A wide variety of unipolar barrier structures have been investigated with this material system. In this report, we will present our recent work on the development of low noise long-wave infrared (LWIR) InAs/GaSb T2-SLs photodetectors. By adopting a so-called pBiBn design, the dark current of LWIR photodetectors is greatly suppressed. The LWIR pBiBn device has demonstrated a dark current density as low as 1.42×10-5 A/cm2 at -60 mV, and R0A of 5365 Ωcm2 at 76 K. A peak detectivity at 7.8 μm of 7.7×1011 cmHz1/2W-1 is obtained at 76 K. Further effort to reduce the operating bias is also reported. By refining the energy-band alignment, a 2-μm-thick LWIR pBiBn device has demonstrated a single pass (no AR coating) quantum efficiency of 20% at 10 μm under zero-bias at 77 K. We have recently extended our efforts to further reduce the dark current by using an interband cascade (IC) photodetector structure. Some further details about the device operation and results will be discussed.
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Z.-B. Tian, Z.-B. Tian, E. A. DeCuir, E. A. DeCuir, N. Gautam, N. Gautam, S. Krishna, S. Krishna, P. S. Wijewarnasuriya, P. S. Wijewarnasuriya, J. W. Pattison, J. W. Pattison, N. Dhar, N. Dhar, R. E. Welser, R. E. Welser, A. K. Sood, A. K. Sood, "Hetero-engineering infrared detectors with type-II superlattices", Proc. SPIE 8868, Infrared Sensors, Devices, and Applications III, 88680L (19 September 2013); doi: 10.1117/12.2032205; https://doi.org/10.1117/12.2032205

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