Research On Tuning The Thermal Conductivity Of Boron Nitride Based On Molecular Dynamics Simulations

Nowadays,the research and manufacturing of electronic components have been conducted at the nanoscale.The problem of heat dissipation is becoming increasingly serious.To solve this problem,scientists are devoted to discovering new nano-materials and investigating thermal properties of these materials.Among these materials,boron nitride,similar to graphene in structure,has excellent thermal properties.So,it is promising to be applied in the development of electronic components.In this paper,the non-equilibrium molecular dynamics simulation method is used to study how to tune the thermal conductivity of boron nitride.The results can provide a theoretical reference to how to achieve more efficient heat control and management when boron nitride is used in electronic devices.The influence of strain and triangular defects on the thermal conductivity of boron nitride is studied.Under the effect of tensile strain,the surface of boron nitride becomes smooth and the thermal conductivity decreases sharply with the increase of strain.Under the effect of compressive strain,the structure of boron nitride is bent and the thermal conductivity decreases slightly.Triangular defects in the boron nitride lead to temperature drops.With the number of defects increasing,thermal conductivity of boron nitride decreases gradually.When the triangle defects are located in the middle of boron nitride,the thermal conductivity in the two directions(from left to right and from right to left)is basically the same.When the defects are on one side,the thermal conductivity in the two directions is obviously different,and simulation of the transient heat flow is conducted to verify this result.The influence of two different forms of interlayer force on the thermal conductivity of boron nitride is studied by increasing the number of layers of boron nitride and constructing the interlayer covalent bonds.The thermal conductivity of boron nitride decreases with the increase of the number of layers.The stronger the van der Waals force is,the more obvious the downward trend is.In the double-layer boron nitride,as the density of the covalent bonds increases,the thermal conductivity decreases rapidly.The thermal conductivity of boron nitride decreases more quickly when the covalent bonds are distributed perpendicularly to the direction of heat flow.The thermal conductivity of boron nitride is studied when silica and graphene are used as the substrate.Besides,an oscillatory substrate is added to further adjust the thermal conductivity.The thermal conductivity of boron nitride decreases when the silica substrate is added.The thermal conductivity of boron nitride increases slightly when the graphene substrate is added.The stronger the substrate interaction is,the more obvious the change of thermal conductivity is.The dimension of the oscillatory substrate is the same as the heat bath.When the substrate vibrates in the hot bath region,the thermal conductivity increases.When the substrate vibrates in the cold bath region,the thermal conductivity decreases.The magnitude of the thermal conductivity change is related to the vibration frequency and vibration direction of the substrate.