Research And Experiment On The Near-field Thermal Radiation Based On Graphene Plasmon

The object with temperature above the absolute zero degree will radiate the electromagnetic waves,the Planck's Radiation law describe the physics of thermal radiation heat transfer in the far filed regime.However,when the size of the bodies or the separation distance is comparable to or smaller than the dominant wavelength which obey the Wien's Displacement Law,it is no longer applicable directly.Near field thermal radiation plays an important role in the nanoscale heat transfer accounting for the wave characteristic of the thermal radiation,broken through the Planck's radiation limit.It has gained great attention in application scenarios such as device thermal management,TPV system,data storage and SThM for the potential in improving their performance.On the other hand,the tunability of graphene plasmon from the mid-far infrared to terahertz enables the coupling of the evanescent waves in the radiation system to enhance the near field thermal radiation.In this thesis,we study the simulation and experiment using the properties of graphene plasmon.A set of experiment devices for measuring the near field thermal radiation is designed and fabricated.Finally,we verify the mechanism of the near field thermal radiation with graphene and measure the heat radiation in the near field.Main research results can be summarized as follows:1.Maxwell's equation combined the fluctuation-dissipation theory is commonly used in the academic to describe the near-field thermal radiation between semi-infinite situation.Using this theory,we calculate the relationship between heat flow with the separation distance,the temperature of emitter,and the material parameters.We calculate the intrinsic silicon system,the doped silicon system,respectively.The near field thermal radiation enhancement from the plasmon of 2D material is also studied.Simultaneously,the corresponding mode is analyzed to make the mechanism of enhancement clear.2.We choose graphene from 2D material for its mature research.The near field thermal radiation spectrum matches the graphene plasmon well,so the single layer graphene's mode distribution is analyzed.We calculate the relationship between heat flow and the seperation and the dispersion of the heat transmission probability.We also discuss the Fermi level of graphene will affect the near field thermal radiation because of tunability of the Fermi level in the experiment.The calculation makes the mechanism of graphene plasmon enhance near field thermal radiation clear and guide the following experiment.3.The material parameters play a decisive role in describing the near filed thermal radiation under real conditions.To confirm this,we use the Drude model in the doped silicon.And the specific parameter of the doped silicon is determined by FTIR as the reference.And we use these parameters to calculate the near field thermal radiation between doped silicon.4.The experiment result verify the enhancement of near-field thermal radiation between two kind of silicon plates and two silicon-graphene samples.We measure the system's heat flux versus the input power with homemade setup under a specific gap distance.The results show that graphene has a significant contribution to the enhancement of near-field thermal radiation.Finally,we summary some experimental schemes and prospects may break through in the near future.