Optical properties of porous silicon

We have measured the absorption spectra and the dispersion of refractive in dex for porous silicon samples with different porosities in the energy rang e 1.5-3.5 eV at room temperatures. The experimental data are compared with the dependences calculated by using Bruggeman's theory for the dielectric c onstant of a multicomponent system composed of crystal silicon, SiO2 , amor phous silicon, and voids (pores). The best agreement between the experiment al and theoretical dependences is achieved for a significant percentage of SiO2 in the porous silicon samples. (C) 2001 MAIK "Nauka/Interperiodica".