Near-Field Thermal Radiation Based On Graphene-hexagonal Boron Nitride Intermediate Modulator

With the development of micro/nano manufacturing technology,electronic devices are becoming more and more integrated and the research of heat transfer based on micro/nano scale becomes more and more important.Radiation is an important form of heat transfer.Due to the tunneling of evanescent waves,the near-field radiation heat transfer between two objects can exceed the Planck blackbody radiation limit,especially when the object supports surface plasmon polarons,surface phonon polarons and hyperbolic phonon polarons.In recent years,with the in-depth study of near-field thermal radiation,the application of thermal radiation has been rapidly developed,such as near-field thermal optoelectronics,thermal imaging,radiation cooling of electronic components and micro-thermal management.In this paper,based on the fluctuation dissipation theory,dyadic green's function and Maxwell's equation,the near-field thermal radiation between three plates based on graphene,hexagonal boron nitride(hBN)and silica dioxide(SiO₂)composite heterostructures were calculated and analyzed.The main research contents include:1.The conductivity of graphene is systematically introduced,and the dielectric functions of hexagonal boron nitride and silica dioxide were calculated.The calculation method of near-field radiation heat transfer net heat flow of the three-body system is given.The Fresnel reflection coefficient and transmission coefficient of the multi-layer media stack are summarized.2.Three-body system consisting of graphene,massive silica dioxide and hexagonal boron nitride films was proposed.The near-field thermal radiation of three-body system and its corresponding two-body system is studied.The effects of physical parameters(chemical potential of graphene,volume spacing and hexagonal boron nitrided film thickness)on the near-field thermal radiation were analyzed,and it is found that the volume spacing have a significant effect on the near-field thermal radiation.In addition,by comparing the radiative heat flux under different physical parameters,the optimal parameters to enhance the near-field radiative transfer were found.At the same time,with the introduction of the modulator,the near-field radiation heat flux of the three-body system is significantly enhanced compared with that of the two-body system.3.The effect of a modulator composed of graphene and hexagonal boron nitide films periodically stacked on near-field thermal radiation was studied.The near-field radiation heat transfer characteristics of multilayer structures are obtained by comparing the multilayer structure with the sandwich structure(modulator is hexagonal boron nitrided film covered with graphene on both sides).In addition,the effects of different parameters of multilayer structures such as chemical potential of graphene,volume spacing and hexagonal boron nitrided film thickness on the thermal radiation coefficient are analyzed and discussed.When the thickness of the multilayer modulator is fixed,the near-field radiation heat flow increases as the number of layers of hexagonal boron nitrate film and graphene is gradually increased,indicating that the number of layers of hexagonal boron nitrate film and graphene in the modulator have an effect on the near-field thermal radiation.By adjusting the chemical potential of graphene of the modulator and the emitter and receiver respectively,it is found that the chemical potential of graphene can have an important influence on the near-field thermal radiation.