Heat recovery mechanism in the excitation of radiative polaritons by broadband infrared radiation in thin oxide films

Abstract

This work probes radiative polaritons in thin oxide layers as a mean to capture and absorb broadband infrared radiation and transform it into heat. A heat recovery mechanism, based on the Seebeck effect, is used as the tool of the investigation. Heat production challenges the current understanding which views the excitation of radiative polaritons as only accompanied by the emission of electromagnetic radiation. The heat recovery mechanism presented here can inspire the design of infrared energy harvesting devices, similar to photovoltaic cells, and other devices to convert energy from a wide range of the electromagnetic radiation spectrum using thermoelectric power generators. V

Excitation of radiative polaritons by polarized broadband infrared radiation in thin oxide films deposited by atomic layer deposition

“…The RPs appear in IR spectra between approximately 100 and 1200 cm À1 , depending upon oxide chemistry. In a previous work, 1 it was found that the 0TH type-RP plays a crucial role in the HRM. The 0TH type-RP is the solution of the tangent equation (T) in the Fuchs-Kliewer model 3 with frequency closer (0th order) to that of the longitudinal optical (LO) phonon (H, because the x LO is the high frequency, whereas x TO is the low (L) frequency phonon mode).…”

“…1 The temperature difference DT is due to the heat produced by the IR radiation absorbed in the thin oxide film and dissipated in the excitation of RPs. 1 A polariton is a mixed excitation resulting from the strong coupling between the transverse optical (TO) phonons and the IR photon field in dielectric (oxide or semiconductor) layers. 3 Different than nonradiative polaritons, 3 the RPs have a phase velocity such that ðx=jkjÞ 2 > ðcÞ 2 , 1,3 where x is the angular frequency, jkj the modulus of the wave-vector, and c the speed of light in vacuum.…”

“…The ability of radiative polaritons (RPs) 3 to absorb IR radiation in thin planar oxide films deposited by atomic layer deposition (ALD) on a metallic substrate was recently proposed through the heat recovery mechanism (HRM). 1 The HRM is the exploitation of the Seebeck effect in thermoelectric (TEC) power generators to produce an electromotive force (EMF) from the temperature difference DT between the "hot" and the "cold" junctions induced by the excitation of RPs in thin dielectric films. 1 The temperature difference DT is due to the heat produced by the IR radiation absorbed in the thin oxide film and dissipated in the excitation of RPs.…”

“…1 The HRM is the exploitation of the Seebeck effect in thermoelectric (TEC) power generators to produce an electromotive force (EMF) from the temperature difference DT between the "hot" and the "cold" junctions induced by the excitation of RPs in thin dielectric films. 1 The temperature difference DT is due to the heat produced by the IR radiation absorbed in the thin oxide film and dissipated in the excitation of RPs. 1 A polariton is a mixed excitation resulting from the strong coupling between the transverse optical (TO) phonons and the IR photon field in dielectric (oxide or semiconductor) layers.…”

Infrared and thermoelectric power generation in thin atomic layer deposited Nb-doped TiO2 films

“…These phenomena in which the Seebeck effect is violated is IR power generation. [11][12][13] The goal of the research presented here is to determine whether the violations summarized above apply in a nanometric power generator (NPG) device in which the active element is a thin TE film deposited by atomic layer deposition (ALD). If the violation of the Seebeck effect applies, then voltage production is not limited by the Seebeck coefficient.…”