16 May 2017 MWIR barrier infrared detectors with greater than 5μm cutoff using bulk InAsSb grown on GaSb substrates
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Abstract
Mid-wavelength infrared photodetectors incorporated into a unipolar barrier architecture with a bulk InAsxSb1-x absorber and an AlSb barrier layer are demonstrated. An extended cutoff was achieved by increasing the lattice constant from 6.09 Å of the GaSb substrate to 6.13 Å using a 1.5 μm thick AlSb buffer layer. This enabled the growth of bulk absorber material with a higher antimony content, InAs0.81Sb0.19, and a greater than 5 μm cutoff. Transitioning the lattice to 6.13 Å also enabled the implementation of a simple binary AlSb layer as a unipolar barrier to block majority carrier electrons and reduce dark current noise. Individual test devices with 4 μm thick absorbers displayed 150 K dark current density, cutoff wavelength, quantum efficiency, and specific detectivity of 3 x 10-5 A/cm2, 5.31 μm, 44 % at 3.4 μm, and 4.3 x 1011 cmHz1/2/W at 5 μm, respectively. The instantaneous dark current activation energy at a given bias and temperature was determined via Arrhenius analysis from the dark current vs. temperature and bias data, and a discussion of valence band alignment between the InAsxSb1-x absorber and AlSb barrier layers is presented. The carrier concentration, mobility, and lifetime of the bulk absorber material and the device performance will be presented and a discussed.
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Neil Baril, Neil Baril, Alexander Brown, Alexander Brown, Daniel Zuo, Daniel Zuo, Meimei Tidrow, Meimei Tidrow, Dmitri Loubychev, Dmitri Loubychev, Joel M. Fastenau, Joel M. Fastenau, Amy W. K. Liu, Amy W. K. Liu, Sumith Bandara, Sumith Bandara, } "MWIR barrier infrared detectors with greater than 5μm cutoff using bulk InAsSb grown on GaSb substrates", Proc. SPIE 10177, Infrared Technology and Applications XLIII, 101771L (16 May 2017); doi: 10.1117/12.2262503; https://doi.org/10.1117/12.2262503
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