Quantification of self-sputtering and implantation during pulsed laser deposition of gold

This work reports on the quantification of self-sputtering and implantation occurring during pulsed laser deposition of Au as a function of the laser fluence used to ablate the gold target. The experimental approach includes, on one hand, in situ electrical Langmuir and optical two-dimensional imaging probes for determining, respectively, ion and excited neutral kinetic energy distributions. On the other hand, it includes determination of the density of i ions reaching a substrate, and ii gold atoms deposited on a substrate as well as of a proportion of atoms that are self-sputtered. The experimental results supported by numerical analysis show that self-sputtering and implantation are both dominated by ions having kinetic energies 200 eV. They are a fraction 0.60–0.75 of the species arriving to the substrate for ablation laser fluences 2.7– 9.0 J cm−2. Self-sputtering yields in the range 0.60–0.86 are determined for the same fluence range.Ministerio de Educación y Ciencias de España-MAT2005-06508-C02-01Unión Europea-HPRN-CT-2002-0032

Polymer-graphene composites by photocuring of a system containing benzophenone macromer

Formulations incorporating benzophenone oligodimethacrylate (BP-DMA) and graphene structures (graphene oxide/GO, reduced graphene oxide/RGO) were exposed to UV/vis irradiation or femtosecond laser beam to achieve hybrid composites. All structures were characterized through various methods including 1H NMR and FTIR spectroscopies, optical microscopy, TEM, SEM/EDAX analysis, and DSC/XRD techniques. The photopolymerization of BP-DMA in monomer compositions with and without GO or RGO was investigated by photo-DSC and FTIR methods for determining the polymerization kinetic parameters. The photopolymerization experiments revealed a good photoreactivity of the monomers (degree of conversion: 65-77%) after 1 minute exposure to UV/vis irradiation and the addition of graphene (up to 0.5%), whereas the polymerization rate varied between 0.14 and 0.1 s-1. Moreover, two-photon photopolymerization of the formulations in presence/absence of GO or RGO nanosheets (0.1 wt.%) generated 2D microstructures by direct laser writing procedure. Also, the morphology and the properties of composites materials were analyzed

Kaolinite Thin Films Grown by Pulsed Laser Deposition and Matrix Assisted Pulsed Laser Evaporation

In this work, thin films of lamellar clays were deposited by laser techniques (matrix assisted pulsed laser evaporation (MAPLE) and pulsed laser deposition (PLD)). The focus of this paper is the optimization of deposition parameters for the production of highly oriented crystalline films. The films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and scanning electron microscopy (SEM). Contact angle measurements were employed to identify the wetting properties of the deposited thin films. Hydrophobic to superhydrophilic films can be prepared by using different deposition techniques and deposition parameters. MAPLE led to superhydrophilic films with contact angles in the range 4°–8°, depending on the microstructure and surface roughness at micro and nano scale. The 1064 nm PLD had a high deposition rate and produced a textured film while at λ = 193 nm an extremely thin and amorphous layer was depicted. Oriented kaolinite films were obtained by MAPLE even at 5 wt.% kaolinite in the target