Near-field Radiation Heat Transfer Of Graphene-covered Silicon And Silicon Carbide In A Non-vacuum Environment

In the micro/nanoscale,if the distance between two objects is smaller than the characteristic wavelength,the photon tunneling effect will play an essential role in the thermal radiation,greatly enhancing the near-field radiation heat transfer.Therefore,near-field thermal radiation is of great significance in engineering applications such as micro-electro-mechanical system or heat transfer enhancement.Possessing unique physical properties such as mechanics and optics,graphene has attracted the great attention of researchers in many fields.Surface plasmon polariton of graphene has wide spectral ranges from terahertz to mid-infrared.In addition,because of the great potential of tunable properties and near-field coupling,graphene exhibited the great advantages of near-field thermal radiation enhancement.In this work,the application of composite structure based graphene in enhancing near-field radiation heat transfer was studied.Based on the background of experimental and engineering applications,the effects of air and other factors on radiation heat transfer were studied,and the controlling and manufacturing method of micro/nano spacing between parallel plates were also indicated.First,from the basic surface electromagnetic wave and fluctuational electrodynamics theory in nano/microscale heat transfer filed,the radiation heat transfer between graphenesilicon composite structure and graphene-silicon carbide composite structure were calculated.The results show that due to the influence of graphene surface plasmon polariton,near-field radiation heat transfer of both structure is obviously improved compared with purely doped silicon plate or pure silicon carbide plate.At the same time,the relevant parameters such as the doping concentration of doped silicon,the vacuum spacing and the chemical potential of graphene,were analyzed and discussed.In the following work,considering the background of experiments and engineering applications,the changes of ratio between air conduction and radiation heat transfer caused by gas pressure and plate spacing parameters were analyzed by the gas dynamics theory.The results show that only when the environment is under high vacuum,air conduction could be ignored.At the same time,the support column structure for controlling the spacing of the plates is designed.Based on the size effect,the influence of the support structure heat conduction on the dominant position of the radiant heat flow were analyzed,and the structural stability of the design scheme was also simulated on a 1 cm × 1 cm substrate.It indicates that the designs of 2 ?m diameter and 1000 ?m array or 1 ?m diameter and 600 ?m array are more suitable.Moreover,according to the existing instruments and equipment of the laboratory,the experimental scheme of support pattern structure between the plates was designed.Through repeated experiments,we determined experimental process parameters which could be reproduced for subsequent near-field experiments,and the problems that may occur in each process were also summarized.