Abstract:The primary objective of this study is the development of transparent thin film materials in the IR enabling strong infrared absorption of organic compounds in the vicinity of metal nanoparticles by the surface plasmon effect. For developing these optical micro-sensors, heterostructures combining gold nanoparticles and chalcogenide planar waveguides are fabricated and adequately characterized. Single As 2 S 3 and Ge 25 Sb 10 Se 65 amorphous chalcogenide thin films are prepared by radiofrequency magnetron sputtering. For the fabrication of gold nanoparticles on a chalcogenide planar waveguide, direct current sputtering is employed. Fabricated single layers or hetero-structures are characterized using various techniques to investigate the influence of deposition parameters. The nanoparticles of gold are functionalized by a self-assembled monolayer of 4-nitrothiophenol. Finally, the surface enhanced infrared absorption spectra of 4-nitrothiophenol self-assembled on fabricated Au/Ge-Sb-Se thin films hetero-structures are measured and analyzed. This optical component presents a ~24 enhancement factor for the detection of NO 2 symmetric stretching vibration band of 4-nitrothiophenol at 1336 cm −1 . 232-239 (1999). 19. L. Tichý, H. Ticha, P. Nagels, R. Callaerts, R. Mertens, and M. Vlcek, "Optical properties of amorphous As-Se and Ge-As-Se thin films," Mater. Lett. 39(2), 122-128 (1999). 20. J. Charrier, M. L. Anne, H. Lhermite, V. Nazabal, J. P. Guin, F. Charpentier, T. Jouan, F. Henrio, D. Bosc, and J. L. Adam, "Sulphide GaxGe25-xSb10S65(x=0,5) sputtered films: Fabrication and optical characterizations of planar and rib optical waveguides," J. Appl.

Semiconductor materials have received substantial attention as photocatalysts for controlling water pollution. Among these materials, perovskite-structured SrSnO 3 is a promising candidate for this application, whereas BaSnO 3 exhibits very low activity. In the present work, Sr 1-x Ba x SnO 3 (x = 0, 0.25, 0.50, 0.75 and 1) was synthesized by solid-state reaction and was applied in the photocatalytic discoloration of the organic dye Remazol Golden Yellow. The perovskite structure was obtained for all compositions of the solid solutions with both Sr The two materials appear to feature different mechanisms of photodegradation: the direct mechanism prevails in the case of BaSnO 3 , whereas the indirect mechanism appears to play a key role in the case of SrSnO 3 .

We have used a set of complementary experimental techniques to characterize an epitaxial structure (25 nm Fe)/GaAs(001) annealed at 450 °C under ultrahigh vacuum conditions. The solid state interdiffusion leads to the formation of an epitaxial reaction layer made of Fe2As patches embedded in a Ga rich Fe3Ga2−XAsX ternary phase. The epitaxial character of this layer explains how the usually reported epitaxial growth of Fe on GaAs performed in the temperature range of 175 to 225 °C is possible in spite of the species intermixing occurring at the interface. Moreover, the observed grains of Fe2As explain the decrease of magnetization at the interface in such contact, since Fe2As is an antiferromagnetic alloy.