8 April 1998 Mid-infrared photodetectors based on the InAs/InGaSb type-II superlattices
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Abstract
We report on the growth and characterization of InAs/InGaSb type-II superlattices (SLs) designed with a photoresponse cut-off wavelength of 10 micrometers . The structural parameters, layer thicknesses and compositions, were chosen to optimize the IR absorption for a superlattice with an energy band gap of 120 meV. The energy band structure and optimized absorption coefficient were determined with an 8 X 8 envelope function approximation model. The superlattices were grown by molecular beam epitaxy and comprised of 100 periods of 43.6-angstrom InAs and 17.2-angstrom In.23Ga.77Sb strain balanced to the GaSb substrates. In order to reduce the background carrier concentrations in this material, SLs grown with different substrate temperatures were compared before and after annealing. The measured photoresponse cut-off energies of 116 +/- 6 meV is in good agreement with the designed value for the SLs. The intensity of the measured mid-IR photoresponse was found to improve by an order of magnitude for the SLs grown at the lower substrate temperature and then annealed at 520 degrees C for 10 minutes. However, the x-ray diffraction spectra were very similar before and after annealing. The temperature dependent Hall measurements at low temperatures were dominated by holes with quasi 2D behavior.
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C.H. Thompson Lin, Gail J. Brown, W. C. Mitchel, Mohamad Ahoujja, Frank Szmulowicz, "Mid-infrared photodetectors based on the InAs/InGaSb type-II superlattices", Proc. SPIE 3287, Photodetectors: Materials and Devices III, (8 April 1998); doi: 10.1117/12.304487; https://doi.org/10.1117/12.304487
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