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Proceedings Paper

Comparison of n- and p-type quantum well infrared photodetectors
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Paper Abstract

Rapid progress in quantum well IR photodetectors (QWIPs) technology has made it possible to develop large format, and high uniformity QWIP focal plane arrays (FPAs) for IR imaging sensor applications. So far, all QWIP FPAs are made of n-type GaAs/AlGaAs material systems grown on GaAs substrates due to the maturity of this material system and excellent detector performance. However, due to quantum selection rules, normal incidence absorption is forbidden in n-type QWIPs. As a result, n-type QWIP FPAs are required to use dielectric or metal gratings to efficiently couple the IR radiation into the quantum wells under normal incidence illumination. On the other hand, normal incidence absorption is allowed in p-type QWIPs without using the grating couplers. This property makes p-type QWIPs potentially more attractive for large format FPA applications. This paper will review the recent development in both n-type and p-type QWIPs for mid-wavelength, long-wavelength and very long wavelength IR detections. The basic device physics, structures, and performance parameters such as dark current, spectral responsivity, and detectivity for both n-type and p-type QWIPs will be depicted. Finally, a comparison of the advantages and drawbacks of n-type and p-type QWIPs will also be given.

Paper Details

Date Published: 11 August 1998
PDF: 15 pages
Proc. SPIE 3553, Detectors, Focal Plane Arrays, and Imaging Devices II, (11 August 1998); doi: 10.1117/12.318094
Show Author Affiliations
Sheng S. Li, Univ. of Florida (United States)
Meimei Z. Tidrow, Army Research Lab. (United States)

Published in SPIE Proceedings Vol. 3553:
Detectors, Focal Plane Arrays, and Imaging Devices II
Pingzhi Liang; Marc Wigdor; William G. D. Frederick, Editor(s)

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