Heterogeneous metasurface for high temperature selective emission

Abstract

We demonstrate selective emission from a heterogeneous metasurface that can survive repeated temperature cycling at 1300 K. Simulations, fabrication, and characterization were performed for a cross-over-a-backplane metasurface consisting of platinum and alumina layers on a sapphire substrate. The structure was stabilized for high temperature operation by an encapsulating alumina layer. The geometry was optimized for integration into a thermophotovoltaic (TPV) system, and was designed to have its emissivity matched to the external quantum efficiency spectrum of 0.6 eV InGaAs TPV material. We present spectral measurements of the metasurface that result in a predicted 22% optical-to-electrical power conversion efficiency in a simplified model at 1300 K. Furthermore, this broadly adaptable selective emitter design can be easily integrated into full-scale TPV systems.

Selective emitters for thermophotovoltaic applications

“…Metamaterial samples are often made of gold, aluminum, or copper with a dielectric as the spacer, such as alumina. The desire to use these samples in high temperature applications has led to the use of a tungsten and other refractory metals as the conductor and exploration of alternate dielectrics such as spin‐on glass , aluminum nitride , strontium titanate , or Ge 2 Sb 1 Te 4 . Metamaterials were first used as perfect absorbers in 2008, when Landy et al fabricated and analyzed an ERR and wire pattern sized to correspond to a peak wavelength in the microwave regime .…”

“…Recent work by Shemelya et al has measured selective emittance at up to 615 °C utilizing platinum as the conducting metal . Further research of these patterns has looked at performance when changing dielectrics and using capping layers and other groups have looked to even higher temperature cycling . Introduction of a thin dielectric capping layer resulted in a slight red shift of the peak in the NIR, though this effect was less apparent as the pattern size increased .…”

“…Introduction of a thin dielectric capping layer resulted in a slight red shift of the peak in the NIR, though this effect was less apparent as the pattern size increased . Heat testing has shown stability of the nanostructures as high as 1300 K in a purely argon atmosphere and 750 °C, or 1023 K, in air . SEM images of the Pt NIR features before and after heating at 750 °C can be seen in Fig.…”

MEMS switchable infrared metamaterial absorber

“…kind of applications demands that the material used for the devices are high temperature stable. [24,25] Refractory materials are been looked into as the potential candidate for absorbers and plasmonics devices to withstand extremely high temperature. [26] The previous report uses Al as a structural layer and hence cannot be used for these applications due to lower melting point and large thermal coefficient mismatch between Al and Al2O3.…”

Low Bandgap InAs-Based Thermophotovoltaic Cells for Heat-Electricity Conversion

“…The main differences between TPV and conventional solar cells are the lower temperature sources found in a TPV system and the much closer proximity of the cell and the extended source. Excellent progress has been made in TPV development 2 covering a wide range of activities including fundamental and applied research into high-temperature nanophotonics 3 and metamaterials 4 to engineer the selective emitter as well as development of heteroepitaxial III-V semiconductor devices 5,11 and micron-gap or near-field heat transfer methods, 6 as well as complete system demonstrations. 7 In this work we are concerned only with the development of the TPV cell.…”