Study on thermal conductivities of Si thin films and porous Si structures based on a modified lattice Boltzmann method

Abstract

In this work, a modified lattice Boltzmann method (LBM) is developed to predict the thermal conductivity of silicon thin films and porous silicon structures, in which a probability parameter is introduced to determine whether a phonon collision event happens at a specific lattice point. The thickness dependent silicon thin film thermal conductivity calculated using this method shows a good agreement with prior experimental and simulation results. We also use this approach to study the porosity and pore-size dependent thermal conductivity of porous silicon structures. Furthermore, the simulated results about thermal conductivity of porous silicon are found to agree well with the previously reported data. The modified algorithm offers substantial computational improvement as compared to current LBM models and enables us to a clearer understanding about the meaning of collision step and streaming step in the LBM model.