TOPIC 1.3.4 Infrared Detectors: Demonstration of Dual-Band SWIR/MWIR Mini-Arrays and FPAs Based on Type-II Superlattices

Project: Research project

Project Details

Description

High performance single-band focal plane arrays (FPAs) are sometimes unable to discriminate a target
from its background when they present similar infrared radiation, at a given wavelength, which may occur
even if the temperatures of the objects are different. Dual-band FPAs offer an additional wavelength that
allows easy identification in such circumstances, and can provide additional functionalities by
incorporating active and passive imaging capabilities in a single all-in-one camera.
Current FPAs (eg. HgCdTe or Quantum Well Infrared Photodetectors) face fundamental and
technological challenges when aiming for a hybrid active/passive imaging. InAs/GaSb/AlSb Type-II
superlattices have been proposed as a viable technology and have already shown equivalent or better
performance compare to the other state-of-the-art infrared detection material systems in single-band
detectors. In this project, we propose to continue the development of Type-II superlattices with Phase I
demonstrating dual-band mini-arrays based on Type-II superlattices, with equivalent performances as the
state-of-the-art single-band devices in the Short-wavelength Infrared (SWIR) and Mid-wavelength
Infrared (MWIR). This phase of the project will aim to understand how to manipulate the band structure
of the superlattice through theoretical investigations, followed by experimental realization through
Molecular Beam Epitaxial growth, and finally, fabricating and characterizing the functional dual-band
mini-arrays that sense in the SWIR and MWIR. This will provide the necessary data and designs for
Option II and Option III.
The Phase I of the project will focus on fabrication and delivery of dual-band SWIR/MWIR miniarrays.
Initial detectivity optimization such that the detectors perform near their theoretical limits, that is,
the detectors are background limited infrared photodetectors (BLIP), will also be studied. Concurrently,
the fabrication process for mini-arrays will be investigated and suitable etch-stop materials and substrate
removal techniques will be developed. Following the successful demonstration of high detectivity backside
illuminated mini-arrays, the effort will focus on minimizing the pixel size for future development of
high uniformity/operability focal plane arrays. Finally, the effort will focus on development of high
uniformity/operability 640×512 focal plane arrays (optional). The focal plane array will be an all-in-one
single-aperture, co-registered dual-band sensor with channels for SWIR and MWIR hybridized to a readout
integrated circuit (ROIC), and ready for system integration and testing.
StatusFinished
Effective start/end date9/1/138/31/17

Funding

  • U.S. Army RDECOM Acquisition Center, Research Triangle Park Contracting Division (W911NF-13-1-0412)

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