The structure of porous Si samples prepared by conventional photoexcited electrochemical etching in hydrofluoric acid solution is presented. Strain enhanced cracking was evidenced at the surface of the sample, which was synthesized at higher incidence angle of light. Combined modes of carbon-fluorine and/or oxygen related impurities, and silicon-oxides are revealed from Fourier transform infrared investigation. A resonant feature at ∼467 nm, originating from a strong coupling of localized excitons at the Si/SiO2 interfacial states and Si–O vibrational modes, is examined during photoluminescence measurements for an excitation wavelength of 320 nm. Furthermore, the appearance of luminescence bands in the range 378–412 nm is discussed in the light of a quantum confinement assisted radiative recombination of electrons and holes at impurity related defects or at the vacancies of neutral oxygen.