Propriétés structurales, optiques et électriques des couches minces de TiO2 dopé Cu obtenues par voie Sol-gel

Des couches minces de TiO<sub>2</sub> dope au cuivre ont ete preparees par la methode Sol-Gel et deposees selon le procede dip-coating sur des substrats en verre. Les proprietes structurales, optiques et electriques des echantillons monocouches dopes 0, 3 et 7 % at. cuivre ont ete analysees par diffraction des rayons X (DRX), microscopie a force atomique (AFM), la spectroscopie ellipsometrique (SE) et spectroscopie UV-Visible. La structure des films est celle d¡¦une phase anatase avec une orientation preferentielle suivant l¡¦axe (101). La transmittance est de l¡¦ordre de 75 % dans le visible et l¡¦energie de la bande optique interdite varie de 3,3 a 2,97 eV. Les valeurs de l¡¦indice de refraction et de la densite de remplissage augmentent avec l¡¦augmentation du dopage en cuivre qui se situe dans l¡¦intervalle 0 a 7 % at. La caracterisation  electrique, realisee a l'aide de la technique de deux pointes, a donne une conductivite electrique maximale de 1,29 (ƒÇcm)-1 obtenue pour le film dope a 7 % Cu.Mots-cles : TiO<sub>2</sub>, anatase, indice de refraction, gap optique, sol-gel

TiO2 waveguides thin films prepared by sol-gel method on glass substrates with and without ZnO underlayer

TiO2 thin films have been deposited on glass substrates with and without ZnO underlayer by sol-gel dip coating process. XRD patterns show the formation of anatase phase with the diffraction lines (1 0 1) and (2 0 0) in TiO2/glass sample. In TiO2/(ZnO/glass) sample, TiO2 is composed of anatase phase with the diffraction line (2 0 0) but the diffraction peaks of ZnO wurtzite are also well-defined. The determination of the refractive index and the thickness of the waveguiding layers has been performed by m-lines spectroscopy. The thickness of TiO2 thin films deduced by Rutheford Backscattering Geometry (RBS) agrees well with that obtained by m-lines spectroscopy. TiO2/glass sample exhibits one guided TE0 and TM0 polarized modes. In TiO2/(ZnO/glass) sample, only, TE0 single mode has been excited due to cutoff condition

A study of nickel and cobalt silicides formed in the Ni/Co/Si(1 0 0) system by thermal annealing

In this work, the Ni/Co/Si system was annealed at temperatures ranging from 300 °C to 800 °C. The samples were characterized by means of X-ray diffraction (XRD), Raman spectroscopy, Rutherford backscattering spectroscopy (RBS), atomic force microscopy (AFM) and sheet resistance measurement. The XRD and Raman spectroscopy results showed that the formation of nickel and cobalt silicides (CoSi, Co2Si, Ni2Si, NiSi, NiSi2, CoSi2) is an annealing temperature dependent diffusion process. The diffusion phenomenon was evidenced by RBS. The low values of the sheet resistance which were correlated with the films surface roughness were attributed to the formation of both CoSi and NiSi phases