Formation of light-emitting structure on the base of porous SIOx films

This work presents the first study of porous light-emitting nc-Si-SiO_x structures obtained by oblique evaporation of SiO in vacuum and thermal post-annealing. Characterization of the samples was done by optical (280-540 nm) ,and infrared absorption (800-1200 cm^-l) spectroscopy and photoluminescence (PL) measurements. The measurements have shown that the density of films gradually decreases from 1.90 g/cm³ to 0.91 g/cm³ and porosity increase respectively with increasing of deposition angle from 0° to 75°. Photoluminescence (PL) is observed only in annealed samples that is connected with Si nanocrystals formation in oxide matrix. Increasing of deposition angle results in the grows of PL intensity and the shift of peak position to shorter wavelengths. The size of nanocrystais and their volume fraction depends on the film´s porosity. Conclusion is made on the possibility of controlled changes of structure and light-emitting characteristics of nc-Si-SiO_x layers by its porosity changes.