Thermal Boundary Resistance Effect on Non-Equilibrium Energy Transport in Metal-Dielectric Thin Films Heated by Femtosecond Pulse Lasers

Abstract

The aim of this study is to investigate the effect of interfacial thermal boundary resistance (TBR) at a metal-dielectric interface on non-equilibrium energy transport in Au/SiO2 films heated by femtosecond pulse lasers. In this paper we suggest a combined set of numerical models that include the two-temperature model (TTM) for a metal side and the heat conduction equation for a dielectric layer. In addition, the TBRs between metal and nonmetal layers are calculated using thermal conductance, which is closely associated with the electron-phonon resistance and phonon-phonon resistance. Herein we present the transient and spatial distributions of TBR for a Au/SiO2 film irradiated by a 100-fs pulse laser with a 1053 nm wavelength, which are substantially affected by the phonon temperature and electron-phonon coupling. We also discuss the effect of laser fluence on the TBR and energy transport. The TBR rapidly increases the thermal conductivity at the interface, and becomes dominant at an early stage of laser irradiation over a very short period and then drastically decreases with time. Moreover, the TBR is substantially affected by the electron-phonon coupling and it should be considered for more accurate prediction of the lattice temperature drop at the interface. [doi:10.2320/matertrans.M2011021]