Heat transfer in two-layered systems excited by a pulsed laser

In this work the temperature distribution in a two-layered material subjected to pulse- laser heating at the front surface is solved analytically. The interfacial contact conductivity, the reciprocal of thermal resistance, existing at the interface between the two layers is included in the analysis. The temperature distribution is calculated in each layer by using the time-dependent one-dimensional heat diffusion equation with appropriate boundary conditions according to the experimental conditions together with the Fourier integral. Within this approximation, we found that the evolution of the temperature at the front surface depend significantly on the interfacial thermal resistance, the thickness and thermal parameters of each layer. In addition, we showed that, in general, the effective thermal diffusivity and thermal conductivity of the layered system cannot be defined. In particular, for the two-layer material composed by Si and GaAs films, the effective thermal parameters can only be defined when the laser pulse duration is short as compared with the characteristic time response of each layer. Our results are in agreement with previous experimental and numerical calculation reported in the scientific literature. (C) 2011 Elsevier Masson SAS. All rights reserved.