17 September 2014 High operating temperature midwave infrared (MWIR) photodetectors based on type II InAs/GaSb strained layer superlattice
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Midwave infrared (MWIR) photodetectors that do not require cryogenic cooling would significantly reduce the complexity of the cooling system, which would lead to a reduction in the size, weight, and cost of the detection system. The key aspect to realize high operating temperature (HOT) photodetectors is to design device structures that exhibit significantly lower levels of dark current compared to the existing technologies. One of the most attractive material systems to develop HOT photodetectors is InAs/GaSb Type II Strained layer Superlattice (SLS). This is due the ability of Type II SLS materials to engineer the band structure of the device, which can be exploited to make devices with unipolar barriers. It has been shown that, compared to the traditional homojunction SLS devices, band-gap engineered unipolar barrier SLS devices can obtain significantly lower levels of dark current. In this work, we report on the design, growth, and fabrication of mid wave infrared detectors based on type-II InAs/GaSb strained layer superlattice for high operating temperatures. The device architecture is the double-barrier heterostructure, pBiBn design. Under an applied bias of -10 mV and an operating temperature of 200 K, the tested devices show a dark current density of 4 x 10-3 A/cm2 and a quantum efficiency of 27%. At 4.5 μm and 200 K, the devices show a zero-bias specific detectivity of 4.4 x 1010 Jones.
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David A. Ramirez, David A. Ramirez, Elena A. Plis, Elena A. Plis, Stephen Myers, Stephen Myers, Laura A. Treider, Laura A. Treider, Eli Garduno, Eli Garduno, Christian P. Morath, Christian P. Morath, Vincent M. Cowan, Vincent M. Cowan, Sanjay Krishna, Sanjay Krishna, "High operating temperature midwave infrared (MWIR) photodetectors based on type II InAs/GaSb strained layer superlattice", Proc. SPIE 9226, Nanophotonics and Macrophotonics for Space Environments VIII, 92260Q (17 September 2014); doi: 10.1117/12.2064045; https://doi.org/10.1117/12.2064045

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