Near-IR Imaging Based on Hot Carrier Generation in Nanometer-Scale Optical Coatings

Krayer, Lisa J.; Tennyson, Elizabeth M.; Leite, Marina S.; Munday, Jeremy N.

doi:10.1021/acsphotonics.7b01021

Cited by 36 publications

(41 citation statements)

References 39 publications

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“…One of the most notable is based on the Tamm plasmon polaritons supported by a thin metal film on a multi-layer Bragg reflector stack [ 29 , 30 , 31 , 32 , 33 ]. Other useful materials include so-called black metals or plasmon super absorbers [ 33 , 34 , 35 , 36 , 37 ], which are comprised of a metal ground plate and a thin overlaying semiconductor film [ 28 , 36 , 38 ]. Absorber design can be optimized for reduced reflectivity and transmittance using the aforementioned optical impedance matching method [ 28 ], which is particularly promising when the refractive index

(where

is the permittivity) of the actual thin film is well known.…”

Section: Introductionmentioning

confidence: 99%

Kirchhoff’s Thermal Radiation from Lithography-Free Black Metals

Kumagai

Balčytis

et al. 2020

Micromachines

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Lithography-free black metals composed of a nano-layered stack of materials are attractive not only due to their optical properties but also by virtue of fabrication simplicity and the cost reduction of devices based on such structures. We demonstrate multi-layer black metal layered structures with engineered electromagnetic absorption in the mid-infrared (MIR) wavelength range. Characterization of thin SiO2 and Si films sandwiched between two Au layers by way of experimental electromagnetic radiation absorption and thermal radiation emission measurements as well as finite difference time domain (FDTD) numerical simulations is presented. Comparison of experimental and simulation data derived optical properties of multi-layer black metals provide guidelines for absorber/emitter structure design and potential applications. In addition, relatively simple lithography-free multi-layer structures are shown to exhibit absorber/emitter performance that is on par with what is reported in the literature for considerably more elaborate nano/micro-scale patterned metasurfaces.

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(where

is the permittivity) of the actual thin film is well known.…”

Section: Introductionmentioning

confidence: 99%

Kirchhoff’s Thermal Radiation from Lithography-Free Black Metals

Kumagai

Balčytis

et al. 2020

Micromachines

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“…By calculating the band structure of combined metallic elements, one can establish a library of possible mixtures with predictive optical/electronic response that are currently not available. In turn, this data could be used as a guideline for identifying the ideal combination of metals for applications ranging from (photo)electrocatalysts to superabsorbers and hot carrier devices …”

mentioning

confidence: 99%

Band Structure Engineering by Alloying for Photonics

Gong

Kaplan

Benson

et al. 2018

Advanced Optical Materials

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at deep sub-wavelengths, [2] leading to a variety of applications including nanolasers, [3] sensors, [4] bioimaging, [5] surfaceenhanced Raman spectroscopy, [6,7] color displays, [8] and others. [9][10][11][12] To improve the performance of today's photonic systems, researchers have extensively investigated the fundamental relation between the wave vector and energy of an SPP wave-named dispersion relation. This quantity describes the propagation of light within a material (i.e., medium), extremely relevant for the abovementioned optical devices. Therefore, understanding the dispersion relation can allow the design of optical materials with superior response, ranging from 2D van der Waals to oxides and metals. Concerning 2D materials, it can uncover the origin of tunable polaritons in hyperbolic metamaterials based on graphene and hexagonal boron nitride (h-BN), which is due to the hybridization of SPP and surface phonon polaritons. [13] As another example, by utilizing the band-edge mode of the dispersion relation in metallic nanocavities, [3] lasing with a 200 times enhancement of the spontaneous emission rate of the dye has been reached. [14] As a class of emerging photonic materials, noble metal alloys with permittivity and localized surface plasmon resonances not achievable by pure metals [9,15,16] have been proposed as alternative candidates for plasmonics [12,[17][18][19][20] because of their tunable dielectric functions, which make it possible to engineer the alloy composition to attain optical properties that will meet desired resonances. In turn, this tunability could be used to Surface plasmon polaritons (SPPs) enable the deep subwavelength confinement of an electromagnetic field, which can be used in optical devices ranging from sensors to nanoscale lasers. However, the limited number of metals that satisfy the required boundary conditions for SPP propagation in a metal/dielectric interface severely limits its occurrence in the visible range of the electromagnetic spectrum. We introduce the strategy of engineering the band structure of metallic materials by alloying. We experimentally and theoretically establish the control of the dispersion relation in Ag-Au alloys by varying the film chemical composition. Through X-ray photoelectron spectroscopy (XPS) measurements and partial density-of-states calculations we deconvolute the d band contribution of the density-of-states from the valence band spectrum, showing that the shift in energy of the d band follows the surface plasmon resonance change of the alloy. Our density functional theory calculations of the alloys band structure predict the same variation of the threshold of the interband transition, which is in very good agreement with our optical and XPS experiments. By elucidating the correlation between the optical behavior and band structure of alloys, we anticipate the fine control of the optical properties of metallic materials beyond pure metals. Band Structure EngineeringThe ORCID identification number(s) for the author(s) of this article can b...

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“…We attribute the loss in responsivity to the change in effective index of the metal film. As the metal is porous the liquid can fill out the voids in the film, and this changes the coupling efficiency to the metallic layer 56 . Likewise, any Fabry-Pérot cavity effect will be lessened as the higher index liquids act as an anti-reflection coating, again lowering the total coupling efficiency to the metallic absorber.…”

Section: Resultsmentioning

confidence: 99%

Giant enhancement of silicon plasmonic shortwave infrared photodetection using nanoscale self-organized metallic films

Frydendahl¹,

Grajower²,

Bar-David³

et al. 2020

Optica

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Many consumer technologies and scientific methods rely on photodetection of infrared light. We report a Schottky photodetector operating below silicon's band gap energy, through hot carrier injection from a nanoscale metallic absorber. Our design relies on simple CMOScompatible 'bottom up' fabrication of fractally nanostructured aluminium films. Due to the fractal nature of the nanostructuring, the aluminium films support plasmonically enhanced absorption over a wide wavelength range. We demonstrate two orders of magnitude improvements of responsivity, noise-equivalent-power, and detectivity as compared to bulk metal, over a broad spectral and angular range. We attribute this to momentum relaxation processes from the nanoscale fractal geometry. Specifically, we demonstrate a direct link between quantum efficiency enhancement and structural parameters such as perimeter to surface ratio. Finally, our devices also function as bulk refractive index sensors. Our approach is a promising candidate for future cost effective and robust short wave infrared photodetection and sensing applications.

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Near-IR Imaging Based on Hot Carrier Generation in Nanometer-Scale Optical Coatings

Cited by 36 publications

References 39 publications

Kirchhoff’s Thermal Radiation from Lithography-Free Black Metals

Kirchhoff’s Thermal Radiation from Lithography-Free Black Metals

Band Structure Engineering by Alloying for Photonics

Giant enhancement of silicon plasmonic shortwave infrared photodetection using nanoscale self-organized metallic films

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