Uysal, Bengü ÖzuğurTepehan, Fatma Zehra2019-06-272019-06-27201270928-07071573-48460928-07071573-4846https://hdl.handle.net/20.500.12469/887https://doi.org/10.1007/s10971-012-2783-xNanostructured silicondioxide thin films were prepared by sol-gel spin coating technique. The SiO2 films were made using a conventional mixture of tetraethoxysilane (TEOS) deionized water and ethanol with various NH3/TEOS ratios. The nanostructured silica films were made using a mixture of the SiO2 sol and regular SiO2 sol to control the enlargement of the particles inside the films. The structural morphological and optical characterizations of the as-deposited and annealed films were carried out using X-ray diffraction (XRD) atomic force microscopy scanning electron microscopy NKD spectrophotometer and ultraviolet-visible (UV-vis) spectroscopy. The transmittance data of the infrared spectra of the films were recorded using an FT-IR Spectrometer. The XRD studies showed that as-deposited films were amorphous and the formation of the alfa-cristobalite phase of the silica film was investigated at annealing temperature close to 1100 A degrees C. Optical properties of the transmittance spectra in the s and p-polarization modes were collected. Refractive indices and extinction coefficients were determined with respect to the NH3/TEOS ratios in the compositions of the films. Optical cut-off wavelength values were investigated from the extrapolation of the absorbance spectra which was estimated from the UV-vis spectroscopy measurements. A red shift in the absorption threshold indicated that the size of silica nanoparticles was increased by an increase in the NH3/TEOS volume ratio from 1:64 to 1:8.eninfo:eu-repo/semantics/openAccessMetaloxidesNanoparticlesSol-gel methodParticle sizeArticle177186163WOS:00030568400002310.1007/s10971-012-2783-x2-s2.0-84863328704N/AQ2