Research On The Thermal Transport And Radiation Properties Of Graphene

Electrically biased graphene as a new type of thermal radiation emitter has been widely studied in experiments.Yet,there is still a lack of systematic theory to quantitatively describe the thermal transport,electrical properties and thermal radiation of electrically biased graphene.In this paper,a heat conduction model is established and developed.The heat transport,electrical properties and radiation of graphene are studied quantitatively.The temperature distribution curve and heat conductivity distribution of graphene are obtained.Finally,the I-V curve and relationship between thermal radiation power and input voltage of graphene is simulated.Our systematic theoretical work will support the design of a new type of high-efficiency wavelength tunable infrared thermal radiation source.The main research contents and results of this thesis are as follows:1.The heat conduction model of electrically biased suspended graphene was studied and deduced,and the relationship between parameters was revealed.The temperature distribution curve and heat transfer coefficient distribution curve of suspended tri-layer graphene were obtained by numerical simulation.The effects of graphene size and bias voltage on the temperature distribution of graphene were also studied.The results show that the higher the bias voltage is,and the larger the width of graphene is,the higher the temperature of graphene is when it is balanced.2.Based on Planck's blackbody radiation formula and the thermal transport properties of graphene,the thermal radiation properties and electrical properties of graphene were further studied.The numerical simulation results are in agreement with the experimental results.For graphene with a specific size,when the voltage exceeds 4V,the thermal radiation power will be significantly increased,which will lead to the phenomenon of graphene luminescence.When the voltage is less than 3.4V,the graphene current increases with the increase of bias voltage;when the voltage is more than 3.4V,the current decreases slowly with the increase of voltage,which is in good agreement with the phenomenon of negative differential conductance.