Structural and optical characterization of pure Si-rich nitride thin films

International audienceThe specific dependence of the Si content on the structural and optical properties of O-and H-free Si-rich nitride (SiN x>1.33) thin films deposited by magnetron sputtering is investigated. A semiempirical relation between the composition and the refractive index was found. In the absence of Si-H, N-H, and Si-O vibration modes in the FTIR spectra, the transverse and longitudinal optical (TO-LO) SiN stretching pair modes could be unambiguously identified using the Berreman effect. With increasing Si content, the LO and the TO bands shifted to lower wavenumbers, and the LO band intensity dropped suggesting that the films became more disordered. Besides, the LO and the TO bands shifted to higher wavenumbers with increasing annealing temperature which may result from the phase separation between Si nanoparticles (Si-np) and the host medium. Indeed, XRD and Raman measurements showed that crystalline Si-np formed upon 1100°C annealing but only for SiN x0.9 , demonstrating that this PL is not originating from confined states in crystalline Si-np. As an additional proof, the PL was quenched while crystalline Si-np could be formed by laser annealing. Besides, the PL cannot be explained neither by defect states in the bandgap nor by tail to tail recombination. The PL properties of SiN x>0.9 could be then due to a size effect of Si-np but having an amorphous phase

Nanoparticle Formation by Femtosecond Laser Ablation

International audienc

Nanoparticle formation by femtosecond laser ablation

International audienc

Epitaxial growth of copper oxide films by cross-beam laser deposition

International audienc

E-MRS Symposium R: “Laser processing and diagnostics for micro and nano applications”: 7–11 June 2010, Strasbourg (France)

Guest editors' preface: The primary goal of the E-MRS is to promote the materials agenda within the European Research Community, focusing on both fundamental and applied issues concerning materials development, characterisation and assessment, functionality, and applications. The Symposium addressed laser and plasma materials synthesis, processing, and diagnostics with a special emphasis on micro- and nano-scale applications across a broad range of science and technologies, directed towards both fundamental and applied end goals. It follows a long lasting tradition (more than twenty years) of topical meetings devoted to the comprehension of laser matter interaction and laser- and plasma-assisted materials processing

Optimisation de la croissance de couches minces par ablation laser

National audienc

Copper oxide phases grown by conventional and cross-beam pulsed laser deposition

International audienc