Thick porous silicon layers were prepared by electrochemical etching on n- and p-type single-crystalline silicon substrate, and characterised by spectroscopic ellipsometry and complementary techniques. The layers were thicker than the penetration depth of light for all wavelengths, so the samples were assumed to be bulk porous material. Best fit was obtained using two-layer models taking into account the surface inhomogeneity. The microstructure of the porous material was characterised using effective medium models with dielectric function reference spectra from the literature or calculated by model dielectric functions (MDF). Using the MDF model, reference dielectric function spectra were generated with different broadening parameters. A good agreement was found between the porosity obtained by ellipsometry and Brillouin scattering.
ASJC Scopus subject areas
- Condensed Matter Physics