[en] Lead based ferroelectric thin films have been grown by pulsed laser deposition (PLD) on Si, MgO and Sapphire substrates starting from sintered targets of Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ (PMN-PT) and (Pb_1-xLa_x)(Zr_0.65Ti_0.33)O₃ (PLZT) with variable PT and La contents, respectively. A parametric study has been performed to investigate the influence of the laser wavelength (266, 355, 532 and 1064 nm), laser fluence (2-25 J/cm²), oxygen pressure (0.2-0.8 mbar), substrate temperature (400-650 deg. C) on the composition and crystallinity, and on dielectric, ferroelectric and piezoelectric properties. Dielectric measurements were done over a wide frequency and temperature range. The dielectric permittivity and loss were investigated for films obtained with different deposition parameters and diffuse-like features were identified in small-grain size microstructured films. The polarization-electric field dependence has been measured at different frequency and temperature conditions. Piezoelectric local probing has been performed and the dependence of longitudinal piezoelectric coefficient on microstructure and texture was obtained

[en] Different phases of boron nitride (BN) nano-structures are synthesized from an hBN ceramic target immersed in acetone, by ablation with a high power pulsed Nd: YAG laser. Transmission electron microscopy (TEM) and electron diffraction (ED) are used to identify the morphology and structure of the prepared colloidal suspensions. It is revealed that by varying solely a single experimental parameter, i.e. the laser pulse fluency, a large variety of BN nano-structures can be produced: nanotubes, very thin graphene-like foils, nano-curls and nano-particles, all with the hexagonal graphite-like hBN structure, as well as high pressure BN phases: orthorhombic explosion E-BN nano-rods, or cubic diamond-like cBN nano-particles.

[en] BaTiO₃ (Barium titanate, BTO) thin films were grown on Pt coated Si substrates by radiofrequency discharge assisted pulsed laser deposition (RF-PLD). A standard experimental set-up consisting in a pulsed YAG-Nd laser working at wavelength of 355 nm and incident fluence in the range of 2-3 J/cm² and assisted by a radio frequency plasma discharge (power RF of about 50-200 W in a O₂ gas flow ranged from 1 to 100 sccm) was used to produce films starting from a BTO ceramic target. Using a special configuration of radio frequency discharge, a beam of excited and/or ionized oxygen species was produced and directed toward the substrate: reactivity increases and oxygen vacancies in deposited thin films were effectively reduced, so thin films dielectric and ferroelectric properties were improved. High dielectric constant values (on the order of hundreds) with losses as low as 0.008-0.08 have been obtained: a comparison with films obtained without RF discharge has been carried out

[en] Plasma treatments of polysulfone membranes in air/monomer mixtures have been performed. The plasma process occurs via polymerization of ablated material from porous polysulfone sample. The investigations (scanning electron microscopy, permeation flux measurements, retention measurements) evidence clear changes of active layer structure. Ultrafiltration composite membranes with improved behaviour in the filtration process (one order of magnitude increase in water permeability and retention improved three times) have been obtained. (Author)

[en] We have performed plasma treatment of polysulfone porous substrates at low monomer flux values. The effects of treatments were investigated by gravimetry, gas permeation and hydrodynamic flux measurements. Measurements show that a process of polymerization of ablated material occurs. Correlation between these measurements and a model for the process of polymeric plasma deposition proposed by us evidences that energy carried by positive ions to substrate have a major role in the synthesis of crosslinked layer. (Author)

No abstract available

[en] A method for obtaining a medium pressure (p∝1 torr), how power (< 100 W), RF-generated plasma jet, suitable for chemical kinetics studies and technological applications is described. Though various supply gases can be used to create the plasma jet, only results on the properties of a nitrogen jet are given in this paper with an emphasis on some spectral and electrical characteristics. The emission spectra of the nitrogen jet are discussed and spatial distributions of the NH(A⁰Π_g, υ'=0) in the bulk of the postdischarge plasma are calculated from the intensity of their vibrational bands. Electrical space resolved double probe measurements and the spatial distributions of the electron density and temperature in the plasma jet are also presented. Possible applications are shortly discussed. (orig.)

[en] The structure and charge transport properties of the poly(ethylene terephthalate) track membrane modified by a pyrrole plasma have been studied. It was found that polymer deposition on the surface of a track membrane via the plasma polymerization of pyrrole results in the creation of a composite nanomembrane that, in the case of the formation of a semipermeable layer covering the pores, possesses conductivity asymmetry in electrolyte solutions - a rectification effect similar to that of a p-n junction in semiconductors. It is caused by presence in the membrane of two layers with different functional groups and also by the pore geometry. Such a type of membranes can be used for creation of chemical and biochemical sensors

[en] We reveal a metastable growth regime during deposition of carbon nanomaterials by PECVD in Ar/H₂/C₂H₂ plasma, characterized by a spontaneous transition of the material morphology from carbon nanofibers (CNF) to carbon nanowalls (CNW), during the same continuous experiment, while keeping constant the values of all deposition parameters (radiofrequency power, gas flow rates, pressure, substrate temperature). Thus, one step deposition of layered architectures consisting of CNW standing on the top of CNF is demonstrated. The peculiarities of the transition in the growth regime, from CNF to CNW are not known. Thus, in this study the plasma characteristics leading to single CNW layers are compared to those leading to CNW onto CNF layered architectures. Mass spectrometry is the main investigation method, confirming that comparing to single layer CNW deposition, the metastable growth proceeds at increased ratios of hydrogen ions to carbon clusters ions. (paper)

[en] SBN thin films were grown on MgO and Silicon substrates by PLD and RF-PLD (radiofrequency assisted PLD) starting from single crystal Sr_0.6Ba_0.4Nb₂O₆ and ceramic Sr_0.5Ba_0.5Nb₂O₆ stoichiometric targets. Morphological and structural analyses were performed on the SBN layers by AFM and XRD and optical properties were measured by spectroellipsometry. The films composition was determined by Rutherford Backscattering Spectrometry. The best set of experimental conditions for obtaining crystalline, c-axis preferential texture and with dominant 31 in-plane orientation relative to the MgO(100) axis is identified. (orig.)