Fabrication of two-dimensional tungsten photonic crystals for high-temperature applications

Araghchini, Mohammad; Yeng, Yi Xiang; Jovanović, Natalija; Bermel, Peter; Kolodziejski, L. A.; Soljačić, Marin; Čelanović, Ivan; Joannopoulos, John D.

doi:10.1116/1.3646475

Cited by 30 publications

(32 citation statements)

References 12 publications

(9 reference statements)

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“…Studies of the influence of various fabrication imperfections show that in this case, the slight broadening of the cutoff and increase of the emissivity above the cutoff wavelength is mostly due to a slight tapering of the sidewalls. Sidewall disorder, i. e. random roughness of the cavity edge can be neglected due to our optimized dry etch process of the Cr hard mask, which allows for precise control of the cavity diameter and smooth edges as compared to a wet etch process (as previously used for W PhCs 24,25 ). Also, we ensured by Auger electron spectroscopy (AES) that there is no contamination from the Cr hard mask after removal of the etch mask, which would be detrimental to the desired low emissivity at long wavelengths.…”

Section: Recent Achievements: Tantalum Photonic Crystalsmentioning

confidence: 99%

“…Recent work on tungsten (W) photonic crystals 16,20,[22][23][24][25] for high temperature applications demonstrated very promising results regarding selective thermal emitters. In our most recent work however, we try to tackle some of the shortcomings of tungsten (e. g. W is extremely difficult to weld, impeding successful system integration) from a materials research point of view and broaden the range of substrate materials used for high temperature photonic applications, and demonstrate how the substrate and its properties can be tailored to meet to the specific needs of the application, including optical, mechanical, and thermo-mechanical properties.…”

Section: Recent Achievements: Tantalum Photonic Crystalsmentioning

confidence: 99%

“…To demonstrate the viability of this approach, we have fabricated Ta PhCs according to our optimized design using a process similar to that used for W PhCs 24,25 and further evolved and optimized for Ta substrates. We use large grain polycrystalline Ta, which is more affordable and readily available even as large area substrates as opposed to single crystal substrates, making large-area applications feasible.…”

Section: Recent Achievements: Tantalum Photonic Crystalsmentioning

confidence: 99%

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Recent developments in high-temperature photonic crystals for energy conversion

Rinnerbauer

Ndao

Yeng

et al. 2012

Energy Environ. Sci.

137

102

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After decades of intense studies focused on cryogenic and room temperature nanophotonics, scientific interest is also growing in high-temperature nanophotonics aimed at solid-state energy conversion. These latest extensive research efforts are spurred by a renewed interest in high temperature thermal-to-electrical energy conversion schemes including thermophotovoltaics (TPV), solar-thermophotovoltaics, solar-thermal, and solar-thermochemical energy conversion systems. This field is profiting tremendously from the outstanding degree of control over the thermal emission properties that can be achieved with nanoscale photonic materials. The key to obtaining high efficiency in this class of high temperature energy conversion is the spectral and angular matching of the radiation properties of an emitter to those of an absorber. Together with the achievements in the field of highperformance narrow bandgap photovoltaic cells, the ability to tailor the radiation properties of thermal emitters and absorbers using nanophotonics facilitates a route to achieving the impressive efficiencies predicted by theoretical studies. In this review, we will discuss the possibilities of emission tailoring by nanophotonics in the light of high temperature thermal-toelectrical energy conversion applications, and give a brief introduction to the field of TPV. We will show how a class of large area 2D metallic photonic crystals can be designed and employed to efficiently control and tailor the spectral and angular emission properties, paving the way towards new and highly efficient thermophotovoltaic systems and enabling other energy conversion schemes based on high-performance high-temperature nanoscale photonic materials.

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Section: Recent Achievements: Tantalum Photonic Crystalsmentioning

confidence: 99%

Section: Recent Achievements: Tantalum Photonic Crystalsmentioning

confidence: 99%

Section: Recent Achievements: Tantalum Photonic Crystalsmentioning

confidence: 99%

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Recent developments in high-temperature photonic crystals for energy conversion

Rinnerbauer

Ndao

Yeng

et al. 2012

Energy Environ. Sci.

137

102

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“…5,[19][20][21] The first method is expensive and limited in throughput and area; the second one is capable of exposing large areas, but is inherently limited to simple patterns such as square lattices of cylindrical cavities. In this study, nanoimprint lithography (NIL) was used as a high-throughput, high-resolution nanostructuring technique that allows for complex and dense patterns to be replicated from a master stamp with high reproducibility and uniformity over large areas.…”

mentioning

confidence: 99%

“…In the past, 2D PhCs for selective emitters and absorbers were fabricated on tungsten (W) and tantalum (Ta) substrates as well as TaW alloys [19][20][21] using electron-beam lithography (EBL) 7 or interference lithography (IL). 5,[19][20][21] The first method is expensive and limited in throughput and area; the second one is capable of exposing large areas, but is inherently limited to simple patterns such as square lattices of cylindrical cavities.…”

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confidence: 99%

Nanoimprinted superlattice metallic photonic crystal as ultraselective solar absorber

Rinnerbauer¹,

Lausecker²,

Schäffler³

et al. 2015

Optica

Self Cite

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A two-dimensional superlattice metallic photonic crystal (PhC) and its fabrication by nanoimprint lithography on tantalum substrates are presented. The superior tailoring capacity of the superlattice PhC geometry is used to achieve spectrally selective solar absorbtion optimized for high temperature and high efficiency solar energy conversion applications. The scalable fabrication route by nanoimprint lithography allows for a highthroughput and high-resolution replication of this complex pattern over large areas. Despite the high fill factor, the pattern of polygonal cavities is accurately replicated into a resist that hardens under ultra-violet radiation over an area of 10 mm 2 . In this way, cavities of 905 nm and 340 nm width are achieved with a period of 1 µm. After pattern transfer into tantalum via a deep reactive ion etching process, the achieved cavities are 2.2 µm deep, separated by 85-95 nm wide ridges with vertical sidewalls. The room temperature reflectance spectra of the fabricated samples show excellent agreement with simulated results, with a high spectral absorptance approaching blackbody absorption in the range from 300-1900 nm, and a steep cut-off. The calculated solar absorptivity of this superlattice PhC is 96% and its thermal transfer efficiency is 82.8% at an operating temperature of 1500 K and an irradiance of 1000 kW/m2. © 2015 Optical Society of America In the last decade, the field of high-temperature photonics is growing rapidly due to an increased scientific interest as well as emerging applications, especially in the field of energy conversion. In this field, the challenges photonic components have to meet are high temperature stability over long lifetimes, high tailoring capacity of the optical properties, and economic fabrication over large areas. In this study, a superlattice PhC consisting of polygonal cavities gave superior control over the spectral properties to achieve a highly selective solar absorber with low thermal emission for high temperature energy conversion applications. For the first time, a metallic superlattice PhC absorber was fabricated by nanoimprint lithography (NIL) as a highthroughput, high-resolution technique paving the way for complex high-temperature photonic components on a large scale. Selective thermal absorbers and emitters are critical components for high temperature and high-efficiency energy conversion applications, such as thermophotovoltaics (TPV), solar TPV, and solar thermal systems. TPV is a thermal-to-electrical energy conversion scheme where thermal emission from a hot radiation source (emitter) drives a suitable photovoltaic cell, promising low maintenance, scalability, high power densities as well as flexibility regarding the employed fuel. In solar TPV (STPV), the irradiation from the sun on an absorber is converted into narrow-band thermal radiation on the emitter side. 1 To reach the high efficiencies predicted by theoretical studies 2-4 it is crucial to (1) reach high operating temperatures (>1000 K) and (2) to employ spectrally select...

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Selective emitters for thermophotovoltaic applications

Pfiester¹,

Vandervelde

2016

Physica Status Solidi (a)

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Applying thermophotovoltaic (TPV) technologies to existing energy generators allows us to increase energy output while utilizing present infrastructure by reclaiming the heat lost during the production process. In order to maximize the efficiency of these sources, the conversion efficiency of the TPV system needs to be optimized. Selective emitters are often used to tailor the spectrum of incident light on the diode, blocking any undesirable light that may lead to device heating or recombination. Over the years, many different technologies have been researched to create an ideal selective emitter. Plasmas and rare‐earth emitters provided highly selective spectra early on, but their fixed peaks required tailoring the diode's band gap to the emitter's characteristic wavelength. Recent advances in engineerable materials, such as photonic crystals and metamaterials, allow the opposite to take place; an appropriate selective emitter can be designed to match the TPV diode, allowing the diode structure to be optimized independently from the emitter.

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Fabrication of two-dimensional tungsten photonic crystals for high-temperature applications

Abstract: Articles you may be interested inLarge-area fabrication of high aspect ratio tantalum photonic crystals for high-temperature selective emitters

Cited by 30 publications

References 12 publications

Recent developments in high-temperature photonic crystals for energy conversion

Recent developments in high-temperature photonic crystals for energy conversion

Nanoimprinted superlattice metallic photonic crystal as ultraselective solar absorber

Selective emitters for thermophotovoltaic applications

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