TECHNOLOGY AREAS: Sensors; Electronics The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 3.5 of the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws. OBJECTIVE: Development of high operating temperature (HOT), large-dynamic range mid-wave infrared (MWIR, 3-5 mm) focal plane arrays for imaging. Design, fabricate, and demonstrate high performance, mid-wavelength infrared (MWIR) detector operating at room temperature and integrate it to commercial ROICs. DESCRIPTION: Photon sensors for the MWIR band of the electromagnetic spectrum require cooling below 180 K for low dark currents and high detectivity. The requirements of smaller gap for full band absorption, thicker absorber for large quantum efficiency, flatter bands for suppressed Auger generation/recombination, and low defect densities for longer Shockley-Read-Hall lifetimes are challenging to simultaneously achieve at elevated temperatures. Several studies including photon trapping and plasmonic structures-coupled detector designs were conducted to increase the operation temperature, but the improvements were limited to 200 K in this wavelength regime. However, detailed calculations continue to predict the possibility of background-limited and thermoelectrically (TE)-cooled operation even at the long wave infrared regime if the structures are fully depleted. PHASE I: Recent advancements in the development of antimonide based Type II superlattice (T2SL) infrared detectors and focal plane arrays abound. Several studies including photon trapping and plasmonic structures-coupled detector designs were conducted to increase the operation temperature. As mercury cadmium telluride (HgCdTe) infrared detector technology continues to push boundaries to increase device operating temperature and achieve larger format arrays, addressing performance limitations in state-of-the-art p n junction photodiodes becomes critical. Decades of research and development on HgCdTe material growth and fabrication techniques have resulted in the achievement of detectors with dark current limited by intrinsic Auger thermal generation processes, rather than by extrinsic dark current mechanisms such as surface conduction, Shockley Read Hall (SRH) centers, or trap-assisted tunneling when CdZnTe substrates are used. A currently favored alternative technology involves replacement of the expensive, not readily available, and relatively small-area CdZnTe wafers with Si wafers. Si wafers offer thermal matching to the Si readout integrated circuit (ROIC), together with thermal cycling reliability, mechanical strength, and large size over CdZnTe substrates. As this is a Direct-to-Phase-II (D2P2) topic, no Phase I awards will be made as a result of this topic. To qualify for this D2P2 topic, the Government expects the applicant to demonstrate feasibility by means of a prior Phase I-type effort that does not constitute work undertaken as part of a prior SBIR/STTR funding agreement. Prior work expected to be completed in a "Phase-I type" effort, in order to qualify for this D2P2, requires demonstrated feasibility which should include work and results in the following areas: For an applicant to demonstrate that its technology is at an appropriate level for a D2P2 award, the applicant should have experience developing numerical simulations and predictive calculations for dark current (Id), quantum efficiency ( ), responsivity (R), NEDT, and detectivity (D*) at elevated operating temperatures for applications similar to the topic above. In addition, proposers need to have the requisite experience and facilities to perform electrical and optical measurements for detector performance characterization. Similar applications may include target identification and recognition, ISR, or other kinds of target detection and surveillance. PHASE II: The awardee(s) will undertake physics based theoretical analysis with metrics for frame rate, dynamic range, resolution and sensitivity architecture with single element detectors. Awardee(s) will develop a road-map for realization of focal plane arrays and obtain experimental data on single element detectors coupled with read-out architectures. Awardee(s) will demonstrate a small format 4x4 fanout of the detector architecture (year 1 deliverable) that is scalable to a 320x256 focal plane array at the end of Phase II. PHASE III DUAL USE APPLICATIONS: Phase III awardee(s) can expect further scaling of performance metrics for dual use applications; and a design for performance approach for defense system in partnership with a defense contractor and a design for cost for commercial applications. REFERENCES: 1. P.R.Guduru, A.J.R., and G.Ravichandran, Dynamic Shear Bands: An Investigation Using High Speed Optical and Infrared Diagnostics. Mechanics of Materials, 2001. 33: p. 371-402. 2. Rogalski, A., P. Martyniuk, and M. Kopytko. "Type-II superlattice photodetectors versus HgCdTe photodiodes." Progress in Quantum Electronics (2019): 100228. 3. T. Specht, Z.Taghipour, T.J. Ronningen, R.Fragasse, R. Tantawy, S. Smith, E. Fuller, W. Khalil, and S. Krishna. "Photodetector Architecture for Open Circuit Voltage Operation of MWIR InAsSb Detectors." IEEE Research and Applications of Photonics in Defense Conference (RAPID), pp. 1-4. IEEE, 2019. KEYWORDS: high operating temperature focal plane arrays; photonic infrared detectors; type II superlattices; large dynamic range; mid wave infrared imagers; enhancing coupling
