Modeling macroscopic elasticity of porous silicon

In this paper we present a model able to predict the elastic properties of nano‐porous silicon (nano‐PSi). Initially developed by Keating [1] for the elastic response of nonprimitive lattices in the harmonic regime, the model accounts for near neighbors (NN) and next‐near‐neighbors (NNN) interactions and leads to numerical results in very good agreement with existent experimental data.We performed numerical tests covering a wide range of porosities between bulk silicon and 90% porosity. We also evidence the significant interplay between the cubic symmetry of the bulk silicon and the shape of the pores. This is of special interest in the case of nano‐PSi due to directional electrochemical etching process and leads, in general, to macroscopic anisotropic elastic response. Our method can be easily extended to cover other porous materials and/or more surface effects like, for example, the back‐bond oxidation (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)