Fractal-like model of porous silicon

A geometrical model of a porous silicon structure is proposed. The resulting size distribution spectra are analyzed by their relation to photoluminescence and Raman scattering. Both experimental data are investigated and compared to those results. The model well describes the presence of a low-energy part of the photoluminescence spectra with wavelength compatible to bulk crystalline silicon. Shapes and positions of Raman and photoluminescence lines are within the frames of model flexibility and indicate similar values of parameters, especially the minimal size of crystallites where Raman scattering and radiative recombination reveal the activity.