Nanodot embedding based optimization of interfacial thermal conductance

Abstract

Regulating the interfacial thermal conductance is a key task in the thermal management of electronic devices, and implanting nanostructures at the interface is an effective way to improve the interfacial thermal conductance. In order to study the effect of the embedding of nanostructures on the thermal conductivity of the interface, the effect of embedding tin (Sn) nanodots at the interface on the interfacial thermal conductance of silicon-germanium (Si/Ge) composite material is investigated by using a non-equilibrium molecular dynamics simulation. It is found that the phonon transmission function of the hybrid interface with embedded nanodots is significantly larger than that of the perfect interface (there are no nanodots at interface). The enhanced transmission function plays a role in facilitating the thermal transport at the interface, which enhances the interfacial thermal conductance. The simulation results also indicate that the interfacial thermal conductance changes nonlinearly with the increase of the number of Sn nanodots, firstincreasing and then decreasing. This is attributed to the competition between two phonon transport mechanisms, which are elastic scattering of phonons and inelastic scattering of phonons. When four nanodots are inserted, the interfacial thermal conductance reaches a maximum value, which is 1.92 times that of a perfect interface. In order to reveal the reason why the interfacial thermal conductance varies nonlinearly with the number of nanodots, the transmission function and density of states of photons are calculated, and the result indicates that the increasing of interfacial thermal conductance is due to the enhancement of phonons inelastic scattering, which opens new channels for the interfacial phonons transport. As the number of nanodots increases to a certain value, the elastic scattering of phonons gradually dominates, and the interfacial thermal conductance starts to decrease. In addition, temperature is also a key factor affecting the interfacial thermal conductance. This study shows that as the temperature increases, more and more high-frequency phonons are excited, the phonons transmission function at the interface keeps increasing, and the enhanced inelastic scattering makes the interfacial thermal conductance keep increasing. This study provides theoretical guidance for improving the interfacial thermal conductance of electronic devices.