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Proceedings Paper

Low-noise QWIPs for FPA sensors with high thermal resolution
Author(s): Harald Schneider; Martin Walther; Joachim Fleissner; Robert Rehm; E. Diwo; K. Schwarz; Peter Koidl; Guenter Weimann; Johann Ziegler; Rainer Breiter; Wolfgang A. Cabanski
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Paper Abstract

We report on novel low-noise QWIP focal plane arrays (FPAs) which allow us to improve the thermal resolution of infrared sensors in the long-wavelength infrared (LWIR) atmospheric window. Our concept uses detector structures with a small photoconductive gain in order to achieve simultaneously a high internal quantum efficiency and a small responsivity. In comparison to conventional QWIPs where each period consists of a quantum well and a thermionic barrier, our approach involves additionally a combination of a narrow quantum well and a tunnel barrier. Due to these additional layers, a high emission probability of the photoexcited carriers and an efficient capture into the ground subband of the subsequent period are simultaneously achieved. FPA cameras using these detectors show an extremely low noise- equivalent temperature difference (NE(Delta) T) and a high dynamic range. In particular, NE(Delta) Ts of only 7.2 mK and 5.2 mK (at 20 ms and 40 ms integration time, respectively) are observed for a 256x256 FPA camera system which we have realized using low-noise QWIPs. This value is the best temperature resolution ever obtained for thermal imagers operating in the LWIR.

Paper Details

Date Published: 15 December 2000
PDF: 10 pages
Proc. SPIE 4130, Infrared Technology and Applications XXVI, (15 December 2000); doi: 10.1117/12.409877
Show Author Affiliations
Harald Schneider, Fraunhofer-Institut fuer Angewandte Festkoerperphysik (Germany)
Martin Walther, Fraunhofer-Institut fuer Angewandte Festkoerperphysik (Germany)
Joachim Fleissner, Fraunhofer-Institut fuer Angewandte Festkoerperphysik (Germany)
Robert Rehm, Fraunhofer-Institut fuer Angewandte Festkoerperphysik (Germany)
E. Diwo, Fraunhofer-Institut fuer Angewandte Festkoerperphysik (Germany)
K. Schwarz, Fraunhofer-Institut fuer Angewandte Festkoerperphysik (Germany)
Peter Koidl, Fraunhofer-Institut fuer Angewandte Festkoerperphysik (Germany)
Guenter Weimann, Fraunhofer-Institut fuer Angewandte Festkoerperphysik (Germany)
Johann Ziegler, AEG Infrarot-Module GmbH (Germany)
Rainer Breiter, AEG Infrarot-Module GmbH (Germany)
Wolfgang A. Cabanski, AEG Infrarot-Module GmbH (Germany)


Published in SPIE Proceedings Vol. 4130:
Infrared Technology and Applications XXVI
Bjorn F. Andresen; Gabor F. Fulop; Marija Strojnik, Editor(s)

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