Research On The Influence Of Interface Structure On Thermal Properties Of Nanomaterials

Nanomaterials are currently the most promising emerging materials and are widely used in various fields such as energy,microelectronics,and bioengineering.With the innovation of manufacturing technology,the miniaturization and integration of electronic components have also been improved.At the same time,the application of nanotechnology has brought the size and characteristic length of the thermal components of microelectronic devices into the nanometer level,thus the thermal management of electronic devices has gradually become the main factor in the service life of electronic components.Nanomaterials offer unprecedented opportunities for thermal management and energy conversion due to their diversification and ease of operation.Due to the high surface-to-volume ratio of nanostructured components and devices,the heat transfer at the interface of nanomaterials usually dominates the overall thermal behavior.Therefore,the interface is extremely crucial to the performance of nanostructured materials.They are the scattering centers of the heat carrier.By changing the interface properties(such as roughness,atomic composition,and chemical bonds),the thermal conduction at the interface can be effectively enhanced.In this paper,two nano-interface structures are constructed based on silicon-based nanomaterials and the interface heat transfer properties are simulated.In this paper,Atomsk is used to construct the structure of introducing Si/Sn atomic mixing layer and Ge intermediate layer at the smooth interface of Si/Sn.The non-equilibrium molecular dynamics simulation method is used to calculate the interface thermal conductance under different layers and different temperatures.And the phonon density of state and phonon participation ratio are calculated.The simulation results show that the interface thermal conductance of the interface introduced the Si/Sn mixing layer increases at first and then decreases with the increase of the number of layers.The interface thermal conductance reaches the peak value when the number of layers is 2.The results of phonon density of states show that the introduced atomic mixing layer enhances the inelastic scattering of phonons at the interface,thus improving the interface thermal conductance.The phonon participation ratio is used to analyze the structure that introduced 2 and 10 mixing layers.As the number of layers increases,the number of phonons showing localized characteristics in the system gradually increases,and the contribution of thermal transport mainly comes from delocalized modes rather than localized modes,thus the thermal conductance gradually decreases.The thermal conductance calculation results show that the introduction of a Ge intermediate layer to the Si/Sn interface cannot effectively improve the interface thermal conductance.The interface introduced Ge intermediate layer can easily scatter high-frequency phonons and low-frequency ones,which leads to a decrease in thermal conductance.The calculation results of the phonon participation ratio show that with the introduction of the intermediate Ge layer,the phonon localization effect is more serious than that of the smooth interface,which further confirms that the decrease in thermal conductance is due to the phonon interface scattering.