Pulsed laser deposited alumino-silicate thin films and amorphous chalcogenide/alumino-silicate structures P. Němec a, ⁎, V. Nazabal b , J. Vávra c , J.-P. Guin d , D. Veselý e , A. Kalendová e , M. Allix f , S. Zhang b , Č. Drašar g a Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice, Czech Republic b Equipe Verres et Céramiques, UMR-CNRS 6226, Sciences Chimiques de Rennes (SCR), Université de Rennes 1, 35042 Rennes Cedex, France c Department of Economy and Management of Chemical and Foodstuff Industries, Faculty of Chemical Technology, University of Pardubice, Stavařov 97-G, 53210 Pardubice, Czech Republic d LARMAUR ERL-CNRS 6274, Université de Rennes 1, 35042 Rennes Cedex, France e Institute of Chemistry and Technology of Macromolecular Materials, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice, Czech Republic f CEMHTI-CNRS, Site Haute Température, Orléans, France g Institute of Applied Physics and Mathematics, Faculty of Chemical Technology, University of Pardubice, Studentská 84, 53210 Pardubice, Czech Republic abstract article info Article history: Received 28 April 2010 Received in revised form 15 September 2010 Accepted 24 September 2010 Available online 1 October 2010 Keywords: Amorphous materials Alumino-silicates Chalcogenide glasses Optical properties Pulsed laser deposition X-ray diffraction Secondary Ion Mass Spectroscopy Alumino-silicate coatings and structures formed from alumino-silicate and amorphous chalcogenide submicrometer layers were prepared by pulsed laser deposition. Fabricated thin films were characterized in terms of their structure, morphology, topography, chemical composition, optical properties, and basic anticorrosive functionality. Prepared coatings are amorphous, smooth, without micrometer-sized droplets, with chemical composition close to parent targets. Spectral dependencies of refractive indices and extinction coefficients were derived from variable angle spectroscopic ellipsometry data. Amorphous chalcogenide/ alumino-silicate structures present large refractive index differences of individual layers (Δn ~ 1.2 at 1550 nm) which could be useful for optical systems working at infrared telecommunication band wavelengths. Basic anticorrosion data of alumino-silicate layers show promising anticorrosion behavior. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Silicon-based ceramics, being represented by silicon carbide and silicon nitride, are widely studied for high-temperature applications such as combustion systems and heat exchangers. At high temperatures, silicon-based ceramics naturally form a protective SiO 2 layer at the surface, which provides effective passivation of the material against dry, oxidizing atmosphere. On the other hand, the surface SiO 2 layer can be degraded and finally destroyed by the presence of water vapor or alkali salts. To eliminate the problem of hot corrosion, environmental barrier coatings, in other words additional protective coatings, are needed for effective protection of silicon-based ceramics [1–6]. Several different coating systems were investigated to protect silicon-based ceramics, for example alumina, zirconia or alumino- silicates. Alumina and zirconia possess excellent corrosion resistance, but both of them differ substantially in the coefficient of thermal expansion when compared with silicon-based ceramics to be protected [2]. Alumino-silicate coatings were shown to be suitable protecting layers having a coefficient of thermal expansion reasonably close to the underlying ceramics. Moreover, such coatings have high- temperature strength, thermal shock resistance and creep resistance, low thermal conductivity and remarkable chemical stability [2,5,6]. Inspecting the Al 2 O 3 –SiO 2 phase diagram, a dramatic increase in refractoriness or temperature resistance is observed at the composition of the incongruently melting intermediate compound mullite with ideal stoichiometry 3Al 2 O 3 –2SiO 2 . This is why mullite is a subject of research in the field of silicon-based protective coatings discussed above. It should be noted that the term mullite is often used to describe more generally the entire range of oxide solid solutions with the general formula Al 2 [Al 2+2x Si 2-2x ]O 10-x , where x is a stoichiometry factor describing the oxygen vacancy concentration in the material [3–5]. In addition to high-temperature protecting layer applications, alumino-silicates could be useful for classical anticorrosive thermally- stable coatings similar to spinels or perovskites [7,8]. It is worthy to mention also the potential use of alumino-silicate coatings as adhesion enhancing layers for organic coatings on inorganic substrates. Finally, due to the expected lower values of refractive indices in comparison with amorphous chalcogenides, it is of interest to use alumino-silicate thin films as a low refractive index layer in multilayered Thin Solid Films 519 (2010) 1341–1345 ⁎ Corresponding author. Tel.: + 420 466038502; fax: + 420 466038031. E-mail address: Petr.Nemec@upce.cz (P. Němec). 0040-6090/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.tsf.2010.09.050 Contents lists available at ScienceDirect Thin Solid Films journal homepage: www.elsevier.com/locate/tsf