Investigation of the thermal-transport properties for silicon nanofilm covered with graphene via nonequilibrium molecular dynamics

Nonequilibrium molecular dynamics (NEMD) is used to investigate the thermal-transport properties of a silicon nanofilm covered with graphene (Gr/Si/Gr nanofilm). The investigation results demonstrate that graphene can enhance the thermal-transport properties and weaken the ballistic characteristics of silicon nanofilm. Under the action of a small strain, the thermal conductivity decreases with the growth of tensile and compressive strain, respectively. In addition, the higher-frequency phonons in graphene give more contributions to the variation of thermal conductivity of Gr/Si/Gr nanofilm under strain. The thermal conductivity of Gr/Si/Gr nanofilm increases linearly with the increase of temperature in the lower-temperature regime due to the quantum effect, and begins to clearly decrease when the temperature exceeds a definite value.