Hydrogenated amorphous silicon oxygen alloy thin films (a-SiOx:H) were prepared on glass and crystalline silicon substrates, with two different oxygen contents: x = 0.15 and x = 0.32. The deposition was realized in an RF-PECVD reactor by using the plasma of the gas mixture SiH4 and CO2 with tunable flow rates. The optical characterization data of the single layers were received from the optical transmittance experiments. Multilayered samples were designed upon the results of the single layers. In depositing the multilayers the repetition of the a-SiO0.15:H/a-SiO0.32:H kernel-pair was used. The samples were prepared as 25-pair of lambda/4 layers, 3-pair of lambda/4 layers and 3-pair of lambda/2 layers. The inner morphologies and nanostructural contents of the films were investigated by Small-Angle X-ray Scattering (SAXS) method. (C) 2014 Elsevier B.V. All rights reserved.