Thermal Conductivity Of Bilayer Graphene Sheets Coupled By Sp~3Hybrid: A Molecular Dynamics Study

Graphene excellent with optical, electrical, magnetic, and mechanicalproperties, has a great potentially application on semiconductor materials, biologicalsensors, information storage, solar batteries and hydrogen storage materials. However,those various performances are closely related with their thermal properties. Therefore,it is important to make a study of the thermal transport properties of graphene. Basedon the non equilibrium molecular dynamics method, we have studied the influence ofsp~3hybridization between the bilayer graphene on the thermal transport properties.The thesis results mainly includes the following aspects:1. Molecular dynamics (MD) simulations are performed to study on the influenceof the thermal transport properties of bilayer graphene nanobelts on the angle betweenthe sp~3hybridization chain and the direction of heat flow. When the angle is90°, thereis an obvious temperature drop at the the sp~3hybridization resulted a Kapitzaconductance. However, there is no obvious temperature drop at the angle of0°，30°and60°. The phonon densities of states show that the phonon mode of vibration ofsp~3atoms in the50-60THZ decrease gradually with the angle increasing，and highfrequency phonon mode of vibration completely disappears at90°.2. We have investigated the influence of space between two sp~3hybridizationchains with sp~3hybridization chains perpendicular and parallel to the heat flux on thethermal transport properties of bilayer graphene nanobelts, respectively. When the sp~3hybridization chains are perpendicular to the direction of heat flow, the Kapitzaconductance of bilayer graphene nanobelts is reduced gradually with the increasingspace between the two chains. When the space between the two chains is greater than9, the Kapitza conductance tends to be stable. However, when the sp~3hybridizationchains are parallel to the direction of heat flow of bilayer graphene nanobelts, thethermal conductivity have achieved stability with the smaller space between the twochains greater than3.3. We found that the number of sp~3hybridization chains has an influence on thethermal transport properties of bilayer graphene nanobelts both with sp~3hybridizationchains perpendicular and parallel to the direction of heat flow. When the sp~3hybridization chains are perpendicular to the direction of heat flow, the Kapitzaresistance linear increase gradually. However, when the sp~3hybridization chains are parallel to the direction of the heat flow, the thermal conductivity reduces graduallywith the number of chains increasing.