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Efficient Near Field Charge Transfer Mediated Infrared Detectors



OBJECTIVE: Develop a scalable and low cost novel charge transfer hetero-interface architecture for high quantum efficiency infrared (IR) detector technology operating at near room temperature with response cutoff wavelengths of 5 and/or 10 micron IR radiation.

DESCRIPTION: Infrared imaging systems have been an important capability for the U.S. Army to ensure day and night situational awareness.In future conflicts, it would be necessary to deploy imaging capability to squad and individual Soldiers.While Longwave Infrared (LWIR) uncooled thermal imaging capability is gradually becoming available to Soldiers, these cameras do not offer flexibility in F/#, sensitivity, frame-rates, or range.High performance Midwave Infrared (MWIR) and LWIR quantum detector based imaging systems can solve many of these issues. However, the cooling requirements, Size, Weight and Power (SWaP) and high cost of production prevents high performance systems at the Soldier level and smaller platforms.Traditional approaches to increase operating temperature in MWIR and LWIR detectors that can operate near room temperature have been unsuccessful. A new approach whereby photon to electron transduction that take advantage of efficient charge transfer across a hetero-interface to separate electron-hole pairs is needed. A recent body of research1-3 in two-dimensional materials has demonstrated promising new optoelectronic devices based on near-field coupling via interface charge transfer.More studies are needed to understand the hetero-interfaces. The underlying concept in these studies is to implement mechanisms similar to Förster or Drexel energy transfer for electron or hole collection leading to very efficient processes.These studies also show promise to increase the operating temperature.For example, energy transfer across van-der-waals hybrids of graphene and transition metal di-chalcogenides may occur via simultaneous two‐way electron transfer via exchange interaction or near‐field non-radiative energy transfer mechanisms such as dipole‐dipole coupling.It should be noted that these studies have been mostly focused on detection of near infrared radiation. There has not been any major work in the longer wavelengths.This topic aims to understand and develop MWIR (2-5 micron) and/or LWIR (8-12 micron) detector technology that can operate near room temperature by implementing and testing the efficacy of the above-stated ideas.The goal is to demonstrate operating temperatures of greater than 250K (MWIR) and 150K (LWIR) with quantum efficiencies better than 60% in both bands. Solutions are being sought for novel innovative concepts to develop either or both bands.

PHASE I: Develop a theoretical model and optimize the optical and electronic charge transfer processes in the chosen hetero-interface structure.Understand the underpinning processes to increase the charge transfer efficiency, interface traps and loss mechanisms.Demonstrate the concept and feasibility of the proposed approach by fabricating single detectors and conducting appropriate materials and detector characterization.Demonstrate proof-of-principle to achieve the above-stated goals.

PHASE II: Based on the Phase I results, perform further development and improvement leading to demonstration of a small array (32 x 32 or larger), test device characteristics in a fan out configuration and deliver to the Government.Conduct a full trade study analysis of the array to establish the case for scalability to larger arrays.Integrate the appropriate array with available Commercial-off-the-Shelf (COTS) ROIC, and build prototype for final delivery of one unit to the Government for laboratory testing.

PHASE III: Develop a manufacturing and commercialization plan by partnering with an established IR camera manufacturing firm.Address any shortcomings in the camera design to meet military applications and requirements.These may include applications such as helmet-mounted, weapon-mounted, and Tier I and II UAS for Intelligence, Surveillance, and Reconnaissance (ISR).

KEYWORDS: MWIR, LWIR, Infrared, Detectors, Focal Plane Arrays, High Operating Temperature


1. S. Islam et al, “Ultra-sensitive graphene–bismuth telluride nano-wire hybrids for infrared detection”, Nanoscale, 2019, 11, 1579; 2. S. Islam et al, “Ultra-sensitive graphene–bismuth telluride nano-wire hybrids for infrared detection”, Nanoscale, 2019, 11, 1579; 3. Konstantatos, G.; Badioli, M.; Gaudreau, L.; Osmond, J.; Bernechea, M.; Garcia de Arquer, F. P.; Gatti, F.; Koppens, F. H., “Hybrid Graphene-Quantum Dot Phototransistors with Ultrahigh Gain”, Nat. Nanotechnol. 2012, 7, 363−368.; 4. Roy et al.“Graphene–MoS2 hybrid structures for multifunctional photoresponsive memory devices” Nat. Nanotechnol. 8, 826 (2013)

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