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Proceedings Paper

Two-color infrared focal plane array based on InAs/InGaAs/GaAs quantum dots in a well detectors design
Author(s): Senthil Annamalai; Philip Dowd; Darren Forman; Petros Varangis; Tom Tumolillo; Allen Gray; Kathy Sun; Mingguo Liu; Joe Campbell; Daniel Carothers; Sanjay Krishna
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Paper Abstract

We report the first two-color 320 x 256 infrared Focal Plane Array (FPA), based on a voltage-tunable InAs/InGaAs/GaAs DWELL structure. The detectors, grown by solid source molecular beam epitaxy (MBE) comprise of a 15-stack asymmetric DWELL structure sandwiched between two highly doped n-GaAs contact layers, grown on a semi-insulating GaAs substrate. The DWELL region consists of a 2.2 monolayer deposition of n-doped InAs quantum dots (QDs) in an In0.15GaAs0.85As well, itself placed in GaAs. The well widths below and above the dots are 50Å and 60Å, respectively. The absorption region asymmetry results in a bias dependent spectral response, with the peak wavelength varying from 5.5 to 10 μm. Using calibrated black body measurements, mid-wavelength and long wavelength specific detectivities (D*) of top-illuminated test pixels at 78K were estimated to be 7.1 x 1010 cmHz1/2/W (Vb= 1.0V) and 2.8 x 1010 cmHz1/2/W (Vb= 2.5V), respectively. Subsequently, a 320 x 256 QDIP FPA array was fabricated on a 30 μm pitch and was hybridized with an Indigo 9705 ROIC. Thermal imaging was successfully carried out at an estimated FPA temperature of 80K, using different optical filters between 3-5 μm, and 8-12 μm, so as to demonstrate two-color operation. The operability of the FPA was greater than 99%, and the noise-equivalent temperature difference was estimated to be less than 100 mK for f#1 (3-5 μm) and f#2 (5-9 μm) optics.

Paper Details

Date Published: 24 August 2005
PDF: 4 pages
Proc. SPIE 5897, Photonics for Space Environments X, 58970P (24 August 2005); doi: 10.1117/12.617775
Show Author Affiliations
Senthil Annamalai, Ctr. for High Technology Materials, Univ. of New Mexico (United States)
Philip Dowd, Ctr. for High Technology Materials, Univ. of New Mexico (United States)
Darren Forman, Ctr. for High Technology Materials, Univ. of New Mexico (United States)
Petros Varangis, Zia Laser Inc. (United States)
Tom Tumolillo, Zia Laser Inc. (United States)
Allen Gray, Zia Laser Inc. (United States)
Kathy Sun, Zia Laser Inc. (United States)
Mingguo Liu, Univ. of Texas (United States)
Joe Campbell, Univ. of Texas (United States)
Daniel Carothers, BAE Systems (United States)
Sanjay Krishna, Ctr. for High Technology Materials, Univ. of New Mexico (United States)

Published in SPIE Proceedings Vol. 5897:
Photonics for Space Environments X
Edward W. Taylor, Editor(s)

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