Epsilon-near-zero tunneling diodes for room-temperature infrared detectors and light sources

OBJECTIVE: Develop, optimize, and demonstrate electrical tunneling-based nanophotonic devices that can sense and emit frequency-tunable infrared light at room temperature through the epsilon-near-zero phenomenon. DESCRIPTION: The Department of Defense (DoD) has an enduring need for imaging systems that operate across infrared (IR) frequencies with low size, weight, power, and cost (SWAP-C). A critical SWAP-C requirement for future systems is the ability to operate at ambient temperature. Recent work shows that tunnel diodes based on metal-insulator-metal (MIM) rectenna structures can convert infrared light into an electrical signal, but efforts have focused on broadband light harvesting, rather than spectrally resolved IR imaging. [1 3] Compound semiconductors, such as cadmium oxide, exhibit low losses at IR frequencies and support zero-index phenomena like epsilon near-zero (ENZ) polaritonic modes. [4 6] Salient features of ENZ modes coherent perfect absorption and extreme field enhancement [6] are ideal characteristics for an absorber layer in a MIM rectenna. Through choice of material and doping, ENZ modes are tunable across the IR, from 1 30 microns [4], narrow-band [5], amenable to charge and energy transfer at ultra-fast time scales [7], and support strong non-linear optical behaviors [8]. MIM diodes run in reverse bias emit light through inelastic electron tunneling, [9 11] so ENZ-based tunnel diodes could also serve as new, tunable IR light sources. PHASE I: Develop concepts supported with feasibility modeling for ENZ-based MIM IR (1) imaging and (2) emitting devices measuring 10x10 pixels, with each pixel separately able to detect or emit four different wavelengths between 2 14 microns, each with a maximum bandwidth of 100 meV. Design for an operating temperature range of -20 50 C. The applied voltage needed to detect IR light should be less than 1V (ideally 0V). Outline the techniques and procedures to fabricate and characterize these devices. Describe a control scheme with which to achieve solid-state beam steering (e.g., phased array) for the emitter device. A highly desirable objective is to experimentally demonstrate IR detection and/or emission at a single wavelength between 2 14 microns using a single-pixel breadboard MIM device. Demonstrate operational temperature of 0 C or above (25 C desired). Characterize optoelectronic performance characteristics 100 meV maximum bandwidth and minimum 3dB minimum signal-to-noise ratio are desired. PHASE II: Based on Phase 1 results, fabricate, test, and demonstrate at least one operational ENZ-based MIM IR imaging device prototype, and at least one operational ENZ-based MIM IR emitter device prototype. Imaging and emitter shall operate fully across a temperature range of -20 50 C, with 100 meV maximum bandwidth and 3dB minimum signal-to-noise ratio at each wavelength. Response times shall be on the order of 100 ps or less. Fully characterize the optoelectronic performance of the imaging device (e.g., I-V curves, signal-to-noise ratios vs. temperature, efficiency, detectivity or D*, etc.) and of the emitter device (power and spectral output, efficiency, etc.). The emitter shall demonstrate an optical phase array that can achieve beam steering over a 60 solid angle. Compare performance against existing commercial IR detectors and emitters that operate at ambient temperatures. PHASE III DUAL USE APPLICATIONS: Demonstrate ENZ-based IR imaging and emitting devices that will be appropriate for integration with existing and/or future DoD IR imaging and signaling systems. Partner with DoD laboratories and interested industrial parties to further define necessary capabilities and metrics, as well as the research and development necessary for commercialization and adoption. Expand devices to 100-by-100 pixels or more, and 25 frequencies or more. Achieve response times of 6 50 femtoseconds for 2 14 micron light. Consideration will include SWAP-C in design. REFERENCES: 1. P. Periasamy et al., Fabrication and Characterization of MIM Diodes Based on Nb/Nb2O5 Via a Rapid Screening Technique , Adv. Mater. 23 (2011), 3080 3085. 2. J. Shank et al., Power Generation from a Radiative Thermal Source Using a Large-Area Infrared Rectenna , Phys. Rev. Applied, 9 (2018), 054040. 3. P.S. Davids et al., Electrical Power Generation from Moderate-Temperature Radiative Thermal Sources , Science, 367 (2020), 1341 1345. 4. N. Kinsey et al., Near-Zero-Index Materials for Photonics , Nat. Rev. Mats., 4 (2019), 742 760. 5. E. Sachet et al., Dysprosium-Doped Cadmium Oxide as a Gateway Material for Mid-Infrared Plasmonics , Nat. Mater., 14 (2015) 414 420. 6. S. Campione et al., Theory of Epsilon-Near-Zero Modes in Ultrathin Films , Phys. Rev. B., 91 (2015) 121408(R). 7. J.A. Tomko et al., Long-Lived Modulation of Plasmonic Absorption by Ballistic Thermal Injection , Nat. Nanotech., 16 (2021) 47 51. 8. Y. Yang et al., High-Harmonic Generation from an Epsilon-Near-Zero Material , Nat. Phys., 15 (2019) 1022 1026. 9. M. Parzefall et al., Antenna-Coupled Photon Emission from Hexagonal Boron Nitride Tunnel Junctions , Nat. Nanotech., 10 (2015) 1058 1064. 10. P. Wang et al., Reactive Tunnel Junctions in Electrically Driven Plasmonic Nanorod Metamaterials , Nat. Nanotech., 13 (2018) 159 164. 11. H. Qian et al., Efficient Light Generation from Enhanced Inelastic Electron Tunneling , Nat. Photon., 12 (2018) 485 488. KEYWORDS: Infrared sensors; nanophotonics; epsilon-near-zero materials; tunneling diodes