Near-Field Radiative Heat Transfer between Dissimilar Materials Mediated by Coupled Surface Phonon- and Plasmon-Polaritons

Abstract

Near-field radiative heat transfer (NFRHT) between dissimilar materials supporting surface polaritons in the infrared is of critical importance for applications such as photonic thermal rectification and near-field thermophotovoltaics. Here, we measure NFRHT between millimetersize surfaces made of 6H-SiC and doped Si, respectively supporting surface phonon-polaritons (SPhPs) and surface plasmon-polaritons (SPPs) in the infrared, separated by a 150-nm-thick vacuum gap spacing maintained via SiO2 nanopillars. For purpose of comparison, measurements are also performed between two doped Si surfaces. The measured radiative flux is in good agreement with theoretical predictions based on fluctuational electrodynamics. A flux enhancement beyond the blackbody limit of ~ 8.2 is obtained for the SiC-Si sample, which is smaller than the enhancement for the Si-Si sample (~ 12.5) owing to the spectral mismatch of the SiC and Si light lines, and SPhP and SPP resonances. However, due to lower losses in SiC than Si and weaker SPhP-SPP coupling than SPP coupling, the near-field enhancement for the SiC-Si sample exhibits a more pronounced monochromatic behavior with a resonant flux that is ~ 5 times larger than the resonant flux for the Si-Si sample. This work demonstrates that it is possible to modulate NFRHT via surface polariton coupling, and will accelerate the development of energy 2 conversion and thermal management devices capitalizing on the near-field effects of thermal radiation between dissimilar materials. KEYWORDS: near-field radiative heat transfer, radiative flux measurement, dissimilar materials, coupled surface phonon-and plasmon-polaritons, silicon carbide, doped silicon 3 Near-field radiative heat transfer (NFRHT), arising when heat sources are separated by subwavelength gap spacings, can significantly exceed Planck's blackbody limit owing to tunneling of evanescent waves. 1-6 These evanescent waves include broadband frustrated modes and narrowband surface polaritons that can lead to quasi-monochromatic radiative flux. 7 Many potential applications of NFRHT, such as near-field thermophotovoltaics, 8-12 photonic thermal rectification 13,14 and flux modulation, 15 capitalize on the coupling of surface polaritons between dissimilar materials. Measurements of NFRHT between dissimilar materials in the microsize sphere-surface (SiO2-Si, 16 SiO2-Au 17 ) and microsize mesa-surface (SiO2-Au, 18 Si- VO2 14 ) configurations have been performed. However, from an application standpoint, the ability to demonstrate NFRHT between macroscale surfaces (~ mm 2 ) is critical, since the heat transfer rate is not only proportional to the near-field enhancement of the radiative flux, but also to the size of the surfaces. NFRHT measurements between macroscale surfaces made of the same materials, namely Si, [19][20][21][22] SiO2, 23-27 Al2O3, 28 Al, 29 graphene, 30 graphene-covered SiO2 31 , and metallodielectric multilayers 32 have been reported. Only Ito et al. 33 measured NFRHT between macroscale surfaces made of dissimilar materials ...

Polariton topological transition effects on radiative heat transfer

“…Among these, the coupling of surface polaritons plays a decisive role in huge heat transfer enhancement [4]. In particular, the nearfield radiative heat transfer (NFRHT) can be far ahead of the blackbody limit, either theoretically or experimentally, via the resonant coupling of surface phonon polaritons (SPhPs) [13] or surface plasmon polaritons (SPPs) [14]. Moreover, the development in fabrication of metamaterials results in extensive studies of the coupling of surface polaritons for NFRHT between metamaterials in theory, such as hyperbolic polaritons [15], magnetoplasmon polaritons [16], ellipse polaritons [17], nonreciprocal polaritons [18], and nonreciprocal hyperbolic polaritons [19].…”

Effective Approximation Method for Nanogratings-induced Near-Field Radiative Heat Transfer

“…When the distance between two objects is comparable to or less than the thermal wavelength, the photon tunneling effect plays an essential role in the thermal radiative transfer, greatly enhancing the near-field radiative heat transfer (NFRHT) past the Planckian blackbody limit by several orders of magnitude [1][2][3][4][5][6]. Numerous theoretical studies on the NFRHT between various materials and nanostructures have been performed, such as transfer between two planar surfaces [1,7,8], two nanoparticles [8,9], two gratings [10][11][12][13][14], one sphere and plane [15], three bodies [16], and so on [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Recently, many experimental reports have indicated that the NFRHT can exceed the blackbody limit for a plane-plane configuration [33][34][35][36][37][38].…”

Toward applications of near-field radiative heat transfer with micro-hotplates

“…Near-field radiative heat transfer (NFRHT) occurs between objects separated by a distance smaller than the wavelength of thermal photons. Some materials (as or 1 ) support Surface Phonon Polaritons (SPhPs), which are electromagnetic surface waves resulting from coupling between light and crystal vibrations. These waves are strong carriers of electromagnetic energy and are confined on the interfaces.…”