High-temperature metal coating for modification of photonic band edge position

Enabling high-temperature nanophotonics for energy applications

“…We further show how the bandgap edge of our PhC can be tailored to theoretically any wavelength of interest, limited only by intrinsic material properties and fabrication limits, by virtue of controlling the cavity's resonant frequency. Using this, we present PhC designs capable of an emission contrast of about 4∶1 over 10% wavelength separation, a marked improvement to previously reported work with an approximate emission contrast of 2∶1 (12,(24)(25)(26)(27)(28). We further show how we are able to achieve designs with maximum emission at larger wavelengths previously unattainable with this material platform.…”

“…However, these designs cannot operate at high temperatures (>1;000 K) due to thermomechanical stresses between layers and interfaces, and chemical reactions between the constituent elements that are initiated at elevated temperatures. Even 3D layer-by-layer structures, such as W woodpile PhC (12,25,28), contain multiple interfaces, thus making them fragile. To overcome the aforementioned shortcomings while still maintaining large index contrast, we select a material platform consisting of robust, single-element, broadband tunable spectrally selective infrared emitters composed of a 2D square array of cylindrical holes with period a, radius r, and depth d etched through a large area metallic surface.…”

“…In this report, we focus on the design, optimization, fabrication, and characterization of the high performance broadband selective emitter with critical emphasis on obtaining optimized optical response providing the necessary bandwidth that translates into higher power density imperative for large scale solid-state energy conversion, high-temperature performance, and long-range fabrication precision over large areas. In this respect, notable experimental efforts include two-dimensional (2D) square cavities fabricated on tungsten (W) using e-beam lithography and fast atom beam etching (26) and the three-dimensional woodpile stacked W PhC fabricated using a layer-by-layer modified silicon process (12,25,28).However, in order to effectively apply nanophotonic materials in emerging high-temperature large scale energy conversion systems, it is imperative to simultaneously achieve high-temperature stability, uniquely sharp contrast between regions of enhanced and suppressed emission, and precise fabrication of periodic nanostructures over large areas while maintaining macroscopic correlation lengths and ensuring a contamination free surface. Our proposed design overcomes these challenges, thus paving the way to what is an emerging new field of high-temperature nanophotonics for energy conversion applications.…”

“…In this report, we focus on the design, optimization, fabrication, and characterization of the high performance broadband selective emitter with critical emphasis on obtaining optimized optical response providing the necessary bandwidth that translates into higher power density imperative for large scale solid-state energy conversion, high-temperature performance, and long-range fabrication precision over large areas. In this respect, notable experimental efforts include two-dimensional (2D) square cavities fabricated on tungsten (W) using e-beam lithography and fast atom beam etching (26) and the three-dimensional woodpile stacked W PhC fabricated using a layer-by-layer modified silicon process (12,25,28).…”

Chemical vapour deposition of Ir-based coatings: chemistry, processes and applications

“…The iridium growth cycle was repeated 1000 times. 60 have implemented ALD thin lm iridium to three-dimensional tungsten woodpile photonic crystals to modify the optical properties of the 3D structure. Iridium coatings were deposited in a custom-built vacuum chamber utilizing computer-controlled gas ow with a base pressure of approximately 10 À3 torr.…”