Near-Field Radiative Heat Transfer Based On Low Dielectric Constant Materials And Its Application

With the rapid development of micro-nano scale science,the near-field radiative heat transfer has attracted wide attention in recent years.When the vacuum gap is reduced to micronano scale,the radiative heat transfer between objects would be dominated by propagative wave and evanescent wave.The radiative heat transfer can be significantly enhanced by bringing them in proximity to each other to allow the tunneling effect of evanescent modes.With the increase of thermal dissipation demand of micro-nano integrated circuit,low dielectric constant material,an universal material of micro-nano integrated circuits,is needed to be explored in near field radiation heat transfer.However,until now,people have focused more on the materials producing large wavevector in near field radiative heat transfer,and the effect of low dielectric constant materials on near field radiative heat transfer has not been discussed.The paper compares the difference of photon transmission coefficient,reflection coefficient,spectral heat flux and local density distribution between the Si C thin film structure and the Si C / low dielectric constant material structure.It is found that the low dielectric constant substrates could modify the symmetric and asymmetric resonance branches of Si C to achieve the control of heat transfer.Then,based on the dispersion relationship and photon transmission coefficient,the effects of different low dielectric constant materials on the symmetric and asymmetric modes of Si C films are discussed.And their trends are summarized and summarized.The paper firstly explores a thermal rectifier based on near-field thermal radiation between a p-type lightly doped silicon bulk?p-LDSi?and a Fabry-Perot?F-P?cavity,made of alternating metal films and low dielectric constant material films on metal substrate.These results show that the introduction of F-P cavity arouses markedly near-field thermal rectification ratio owing to the selective emittance and absorption.At the same time,due to the coupling of non-resonant evanescent waves,a good rectification ratio can still be obtained under a larger vacuum gap.Furthermore,in order to solve the multidimensional optimization difficulties often encountered in designing thermal rectifier devices,the sequential quadratic programming?SQP?is employed to build the optimal reconstruction scheme by solving the inverse problem for the thermal rectifier.These results finds that the use of optimal parameters can outperform the counterpart?a simple rectifier consisting of a hypothetical metal and p-LDSi?with a 26% improvement in rectification ratio.Finally,this paper theoretically analyzes the performance of using nanoparticle doping technology to stimulate near-field negative electroluminescence refrigeration of low dielectric constant material.The emitter consists of graphene/Si C core-shell?GSCS?nanoparticleembedded thin film of Si deposited on bulk Si.As a low dielectric constant material for the band gap frequency of semiconductors,Si cannot perform good heat transfer above the band gap frequency.By embedding graphene/Si C core-shell nanoparticles,a new surface phonon polaritons is introduced for the Si film above the bandgap frequency,thereby achieving radiative heat transfer above the bandgap frequency.This paper analyzes the performance of near-field negative electroluminescent refrigeration for various bias voltages,various cryogenic temperatures,various volume fractions and various chemical potentials of GSCS nanoparticles.Through the optimization of these parameters,for d = 10 nm and?T= 5K,the best efficiency and the best refrigerated powe can reach 1.25 and 2677.86 W·m^-2,respectively.