The cross section of electroluminescent (EL) porous silicon layers (LEPOS) made fromn‐ andp‐doped silicon has been investigated by means of micro‐Raman and photoluminescence (PL) spectroscopy to find the luminescence active zone in LEPOS. Special care has been taken to avoid the heating of the sample. Additionally an energy dispersive spectroscopy scan over the sample cross section has been performed forn‐LEPOS to detect the distribution of oxygen. Since thensamples display much better EL properties than thepsamples, the investigations concentrate on thensamples. Forn‐LEPOS, a layered structure has been found with SiOx/Si at the top followed by a PL active layer. There are two types of samples showing different forms of Raman spectra. Type‐I spectra are narrow and shifted by small values as compared with the Raman spectra of bulk silicon. They have a shoulder at about 510 cm−1only in the PL active layer. Type‐II spectra are broad and shifted by about 7–10 cm−1. All the electroluminescent samples show Raman spectra of type I.