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Proceedings Paper

Electromagnetic modeling of QWIP FPA pixels
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Paper Abstract

Rigorous electromagnetic (EM) field modeling is applied to calculate the external quantum efficiency (QE) of various quantum well infrared photodetector (QWIP) pixel geometries with thinned substrates. We found that for a 24 × 24 × 1.5 μm3 cross-grating QWIP, the QE is peaked at 13.0, 11.0, and 8.4 μm, insensitive to the grating periods. These peaks are identified as the first three harmonic resonances associated with the pixel resonant cavity. For a regular prismshaped corrugated QWIP (C-QWIPs) with a 25-μm pitch, the QE oscillates about its classical value of 24.5% within the calculated wavelength range from 3 to 15 μm. A peaked value of 32% occurs at 9.1 μm. For pyramidal C-QWIPs, the maximum QE is 42%, and for cone-shaped C-QWIPs, it is 35%. In the presence of an anti-reflection coating, the oscillation amplitude diminishes, and the average values generally rise to near the peaks of the oscillations. The modeling results are compared with the experimental data for grating QWIP focal plane arrays (FPAs) and prismshaped C-QWIP FPAs; satisfactory agreements were achieved for both. After verifying our EM approach, we explored other detector geometries and found new types of resonator QWIPs (R-QWIPs) that can provide 30% QE at certain wavelengths on a 1.5-μm-thick active material. Combining the high QE of a resonator and the high gain of a thin material layer, the new R-QWIPs will have a conversion efficiency far higher than the existing QWIP detectors. The present resonator approach will also have an impact on other detector technologies.

Paper Details

Date Published: 20 May 2011
PDF: 14 pages
Proc. SPIE 8012, Infrared Technology and Applications XXXVII, 80120R (20 May 2011);
Show Author Affiliations
K. K. Choi, U.S. Army Research Lab. (United States)
M. D. Jhabvala, NASA Goddard Space Flight Ctr. (United States)
D. P. Forrai, L-3 Communications Cincinnati Electronics (United States)
A. Waczynski, NASA Goddard Space Flight Ctr. (United States)
J. Sun, U.S. Army Research Lab. (United States)
R. Jones, L-3 Communications Cincinnati Electronics (United States)

Published in SPIE Proceedings Vol. 8012:
Infrared Technology and Applications XXXVII
Bjørn F. Andresen; Gabor F. Fulop; Paul R. Norton, Editor(s)

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