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 nonequilibrium energy transport in Au/SiO 2 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/SiO 2 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.

Large-Area Fabrication of Laser-Induced Periodic Surface Structures on Fused Silica Using Thin Gold Layers

“…Consequently, hot electrons excited by the deposited laser energy can penetrate deep into the material before an interaction with the lattice takes place, which is why L c can noticeably exceed l α . As the energy transport across the metallic–dielectric interface can occur via electron–phonon and phonon–phonon coupling [ 35 , 36 ], the increased interfacial electron density resulting from the diffusion of the hot electrons leads to an increased interfacial energy transfer [ 24 , 28 ]. In contrast to the energy coupling to the uncoated glass surface, which is solely based on strongly non-linear multiphoton processes, this leads to a stronger, more uniform deposition of the energy to the fused silica substrate and thus to the significant reduction of the LIPSS formation threshold.…”

Phonon transport in aluminum and silicon film pair: laser short-pulse irradiation at aluminum film surface

“…They demonstrated that that the temporal evolution of electron and phonon temperatures in nanometre sized gold films was very different from macro-scale films. The effect of thermal boundary resistance on nonequilibrium energy transport in metal-dielectric thin films because of femtosecond pulse laser heating was examined by Lee and Lee [13]. Their findings indicated that the thermal boundary resistance rapidly increased the thermal conductivity at the interface, and it became dominant at an early stage of laser irradiation over a very short period.…”

Ablation area quasiperiodic oscillations in semiconductors with femtosecond laser double-pulse delay

“…And at the same total fluence, the oscillation amplitudes in Au-plated ZnO are much larger. Electrons in Au film are heated to a high temperature during irradiation, and the fast hot-electron diffusion by the Au film increases the interfacial carrier density and enhances the interfacial electron-phonon coupling [24,25]. The higher interfacial carrier density in the Au-plated ZnO can lead to a shorter oscillation period of ablation areas.…”