Research On Near Field Radiative Heat Transfer Between Tungsten And Doped Silicon Plates

With the development of nanotechnology,nano manufacturing process and micro/nano electromechanical system(MEMS, or NEMS) in recent years, classical heat transfer theory is facing a new challenge. At micro scale or nanoscale, the radiative properties are extremely different from that at macro scale. The classical theory could not explain many phenomena at micro scale or nanoscale, such as photon tunneling, etc. Therefore, near-field thermal radiation, as a new emerging subject, gets a lot of attention.This thesis starts from Maxwell's equations and the fluctuating dissipation theory,uses electromagnetic theory to describe radiated electromagnetic fields caused by thermal motion of dipole within objects; then presents the mechanism of evanescent wave and surface polariton; then through solving Dyadic Green's function to get the expressions to calculate the near field thermal radiation flux between semi-infinite plane and thin film.The properties of near-field thermal radiation between tungsten and silicon are investigated. Both of these two materials are very common and representative. We studied the contribution of distance, polarized waves, temperature, doping level to the spectral distribution of radiative heat flux. With the doping level of silicon increasing, a new peak is presented in the spectral distribution of near-field radiative heat flux. This new peak locating at low angular frequency is caused by surface photon-polaritons(SPPs), and may have the same order of magnitude with the other peak in the high angular frequency. It's properties is analyzed.The possibility of tuning near-field radiation via thin films is afterwards investigated. Results reveal that the thickness of films affect the spectral distribution greatly. When tungsten is film, it's impacts on the calculating results are difference from the situation when silicon is film. Then we study the effect of metal substrate, which is necessary in real application. The substrate can support silicon, or as a thermal management system to adjust the temperature of silicon. The results have the guiding significance for the further research.