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Advances on photoconductive InAs/GaSb type-II superlattice long-wavelength infrared detectors for high operating temperature

: Müller, Raphael; Niemasz, Jasmin; Daumer, Volker; Janaszek, Andrzej; Jureńczyk, Jarosław; Rehm, Robert


Jiang, Shibin (ed.) ; Society of Photo-Optical Instrumentation Engineers -SPIE-, Bellingham/Wash.:
Optical Components and Materials XVI : 2-7 February 2019, San Francisco, California, United States
Bellingham, WA: SPIE, 2019 (Proceedings of SPIE 10914)
Paper 1091416, 8 pp.
Conference "Optical Components and Materials" <16, 2019, San Francisco/Calif.>
Conference Paper
Fraunhofer IAF ()
HOT; TEC; InAs/GaSb; T2SL; photoconductor; immersion; Infrared detector; LWIR

The fabrication and characterization of InAs/GaSb type-II superlattice long-wavelength infrared (LWIR) photodetectors for high operating temperature (HOT) are assessed regarding possible device yield. We investigate laterally-operated photoconductors with a detector cutoff wavelength in the LWIR at an operating temperature accessible with 3-stage thermoelectric cooling, realized by suitably tailoring the layer composition. Type-II superlattices with a layer composition of 14 monolayers InAs and 7 monolayers GaSb are grown on semi-insulating 3-inch GaAs substrates. We report on the growth of three different buffer layer variants that serve as growth templates for GaSb-based layers on GaAs substrates. The characterization of 75 nominally equal single element detectors per sample evidences the reliability of device processing. The electro-optical evaluation of a randomly chosen subset indicates a high uniformity of responsivity and noise of LWIR InAs/GaSb HOT photoconductors. At 210 K, the devices operate at a cutoff wavelength of 10.5 μm and achieve a mean peak spectral detectivity of 3.3 × 108 Jones.