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Proceedings Paper

Limiting dark current mechanisms in antimony-based superlattice infrared detectors for the long-wavelength infrared regime
Author(s): Robert Rehm; Florian Lemke; Johannes Schmitz; Matthias Wauro; Martin Walther
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Paper Abstract

A detailed understanding of limiting dark current mechanisms in InAs/GaSb type-II superlattice (T2SL) infrared detectors is key to improve the electrooptical performance of these devices. We present a six-component dark current analysis which, for the first time, takes account of sidewall-related dark current contributions in mesa-etched T2SL photodiodes. In a wide temperature range from 30K to 130K, the paper compares limiting mechanisms in two homojunction T2SL photodiode wafers for the long-wavelength infrared regime. While the two epi wafers were fabricated with nominally the same frontside process they were grown on different molecular beam epitaxy systems. In the available literature a limitation by Shockley-Read-Hall processes in the space charge region giving rise to generation-recombination (GR) dark current is the prevailing verdict on the bulk dark current mechanism in T2SL homojunction photodiodes around 77K. In contrast, we find that investigated photodiode wafers are instead limited by the diffusion mechanism and the ohmic shunt component, respectively. Furthermore, our in-depth analysis of the various dark current components has led to an interesting observation on the temperature dependence of the shunt resistance in T2SL homojunction photodiodes. Our results indicate that the GR and the shunt mechanism share the same dependence on bandgap and temperature, i.e., a proportionality to exp(-Eg/2kT).

Paper Details

Date Published: 4 June 2015
PDF: 11 pages
Proc. SPIE 9451, Infrared Technology and Applications XLI, 94510N (4 June 2015); doi: 10.1117/12.2177091
Show Author Affiliations
Robert Rehm, Fraunhofer Institute for Applied Solid State Physics (Germany)
Florian Lemke, Fraunhofer Institute for Applied Solid State Physics (Germany)
Johannes Schmitz, Fraunhofer Institute for Applied Solid State Physics (Germany)
Matthias Wauro, Fraunhofer Institute for Applied Solid State Physics (Germany)
Martin Walther, Fraunhofer Institute for Applied Solid State Physics (Germany)

Published in SPIE Proceedings Vol. 9451:
Infrared Technology and Applications XLI
Bjørn F. Andresen; Gabor F. Fulop; Charles M. Hanson; Paul R. Norton, Editor(s)

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