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Nanomaterials

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Carbon- or nitrogen-containing nanostructured thin films

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The focus of this proposal is on multifunctional thin films. It continues the successful story of previous E-MRS Meeting Symposia. The major objective is to provide a fruitful exchange platform for scientists and engineers working in the multidisciplinary research field of design, synthesis, characterization and application of these films.

 

Scope:

Carbon- or Nitrogen-Containing Nanostructured Thin Films exhibit multifunctional properties, different from those of the constituents. These films offer a wealth of structures, e.g. based on metastable phases, nanocomposites or nanosized multilayers, giving rise to unique combinations of optical, optoelectronic, magnetic, electrical and mechanical properties. Metastable films can be designed consisting of plasma polymers, diamond-like carbon or CNx phases. Nanocomposite films can be tailored by adding either metallic (e.g. Ti), non-metallic (e.g. Si) elements with high C or N affinity, or metallic elements with no C or N affinity (e.g. Cu) in an amorphous or crystalline matrix.

The objective of this symposium is to highlight the experimental and theoretical progress in development of carbon- or nitrogen-containing nanostructured films consisting of nanocrystalline particles embedded in an inorganic and/or organic matrix. A multitude of matrixes can be imagined, e.g. C or Si based. Nanolaminated structures such as MAX-phases, plasma polymers, as well as carbon nanotubes, graphene or other low-dimensional structures embedded into a matrix, are also in the scope of this symposium. Contributions investigating plasma composition – material structure - films property – relationships by experimental and theoretical means will be considered. Films’ synthesis by advanced processes, such as high power impulse magnetron sputtering, atmospheric plasma processes, and hybrid techniques are of interest. Papers elucidating mechanical, tribological, thermal, electrical, optical, optoelectronic and magnetic properties, biomedical compatibility, and correlations between these properties and deposition parameters, structure or films’ composition are also encouraged.

Topics such as process modeling and diagnostic techniques, surface interaction and nucleation phenomena, investigation of degradation mechanisms e.g. phase and microstructure stability under different environments and coating-substrate interdiffusion, are also welcomed.

Engineering-oriented contributions including automotive, chemical, electrical, optical, magnetic/optical data storage, pharmaceutical or biomedical applications, and emerging applications as in energy systems, will also be considered.

 

Hot topics to be covered by the symposium:

  • Physical/chemical vapor deposition of thin films
  • Novel fabrication and synthesis routes
  • Modeling of growth processes and film properties
  • Relations between synthesis conditions, plasma composition, material microstructure and thin films properties
  • Mechanical, tribological, thermal, electrical, dielectric, optical, optoelectronic and magnetic properties as well as biomedical compatibility of thin films and coated materials
  • Degradation mechanisms linked to phase and microstructure stability and interdiffusion
  • Development of reliable characterization procedures
  • Automotive, chemical, electrical, magnetic storage data, optical, energy-saving, pharmaceutical, biomedical and energy-relevant applications.

 

Publication:

The proceedings will be published as a special issue of the journal Thin Solid Film (Elsevier).

 

Sponsors:

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Symposium organizers:

 

Mariana Braic
National Institute for Optoelectronics
409 Atomistilor Str.
Magurele-Bucharest
Romania
Phone: + 40(0)214575759
Fax: + 40(0)214575759
mariana_braic@inoe.ro

 

Jochen M. Schneider
RWTH Aachen University
Kopernikusstr.10
D-52066 Aachen
Germany
Phone: +49(0)2418025966
Fax: +49(0)241802295
schneider@mch.rwth-aachen.de

 

Rony Snyders
Mons University
23, Place du Parc
7000 Mons
Belgium
Phone: +32(0)65554955
Fax: +32(0)65554941
rony.snyders@umons.ac.be

 

Thien-Phap Nguyen
Laboratoire de Physique des Matériaux et Nanostructures
Institut des Matériaux Jean Rouxel
2, rue de la Houssinière
44322 Nantes Cedex 3
France
Phone: +33 (0)2 40373976
Fax: +33(0)2 40373991
Thien-Phap.Nguyen@cnrs-imn.fr

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09:15
Authors : C. NİTA, L. DUTA, G.E. STAN*, C POPESCU, V. CRACİUN, M. HUSANU*, B. BİTA**, R. GHİSLENİ***, C. HİMCİNSCHİ****, A. C. POPESCU
Affiliations : National Institute for Lasers, Plasma and Radiation Physics, Magurele, Romania, * National Institute for Materials Physics, Magurele, Romania, **National Institute for Research and Development in Microtechnologies, Bucharest, Romania ***EMPA, Swiss Federal Laboratories for Materials Science and Technology, Thun, Swizerland **** Institute of Theoretical Physics, TU Bergakademie Freiberg, Freiberg, Germany

Resume : Hard carbon thin films were synthesized on Si (100) and fused silica substrates by Pulsed La-ser Deposition in vacuum or methane ambient in view of studying their suitability for applica-tions requiring high mechanical resistance to shock and friction in high temperatures and harsh environments. The deposited layers were investigated in terms of surface morphology by AFM and SEM, crystalline status by XRD, packing and density measurements by XRR and bonding architecture by Raman spectroscopy and XPS. The films adherence was determined by pull-out tests, the surface energy was inferred from contact angle measurements, hardness (H) end elastic modulus (E) were assessed by nanoindentation and wear resistance by nanotribology. The films had a high tendency to exfoliate on fused silica, requiring special optimizations of the deposition process in terms of laser fluence and substrate temperature for stabilization, while being adherent on Si in all deposition conditions. The deposition gas pressure played a crucial role in films thickness, structure and mechanical properties. All films were smooth, amorphous and composed of a mixture of sp3-sp2 carbon, with sp3 content ranging between 50-90%. The load-displacement curves resulted from nanoindentation evidenced that the approximately equal ratios of sp3-sp2 in films content induced a higher hardness (30 GPa vs 5 GPa) and elasticity (E=190 GPa vs E=70 GPa) as compared to structures composed mainly of sp3 bonds (>85%).

G.G.I.2
14:45
Authors : Anton Manakhov, Lenka Zajickova, Marek Elias, Jan Cechal, Josef Polcak, Stepanka Bittnerova, David Necas, Adrian Stoica, Petr Klapetek
Affiliations : Masaryk University, Brno, Czech Republic; Masaryk University, Brno, Czech Republic; Masaryk University, Brno, Czech Republic; Brno University of Technology, Brno, Czech Republic; Brno University of Technology, Brno, Czech Republic; Masaryk University, Brno, Czech Republic; Masaryk University, Brno, Czech Republic; Masaryk University, Brno, Czech Republic; Czech Metrology Institute, Brno, Czech Republic

Resume : Amine-rich films prepared by plasma polymerization have a great potential for biomolecule immobilization, microfiltration membranes, enzyme electrodes, adhesion enhancement or biosensor applications. The bioapplications require good stability in water. However, increased plasma polymer cross-linking, leading to improved film stability, is achieved on the expenses of the amine-group density. Cyclopropylamine (CPA) is a promising monomer recently used for the deposition of amine-rich thin films but the stability of CPA plasma polymers in the contact with water was not yet reported. In this work, low pressure capacitively coupled plasma polymerization of CPA is studied with respect to the discharge mode, continuous wave and pulsed, and CPA flow rate. The analyses reveal complex structure of cyclopropylamine plasma polymers containing hydrocarbon chains, primary and secondary amines, nitriles and possibly imines. In pulsed discharges, it is possible to deposit films with the N/C ratio above 0.24 using higher monomer flow rate. At the optimized monomer flow rate the film exhibits only 20 % thickness loss after 48 hours of immersion in water and still contains about 5 at.% of the NHx environment. It is found that immersion in water lead to the formation of complex nano- and microstructures due to a compressive stress induced by the interaction of the layer with water molecules and the mechanism of chemical changes and amine-rich film degradation is reported.

G.G.II.3
16:00
Authors : Yongtae Kim, Hyun-Soo Kim
Affiliations : Semiconductor Materials & Devices Lab., Korea Institute of Science and Technology, Seoul, Korea

Resume : We have doped carbon atoms in the InSbTe (IST) alloys and investigated phase change mechanism and electrical performance of multi level cell (MLC) phase change random access memory (PRAM). Among Te-based chalcogenide materials, the IST has been already reported as a promising candidate for MLC-PRAM. However, during the phase transformation process migrations of vacancies and atom generate voids and volume change in the IST, which may result in failure of retention and resistance drift. Increasing the C concentration from 0 to 8.4, and 12.5 at.% glass transition temperature increases from 300 to 370, and 440℃, respectively. The activation energy is also increased from 5.138, to 5.278 and 5.398 eV. High resolution transmission electron microscopy shows that the C atoms form C graphite planes, which interrupts inter-diffusion between the the InSb and the InTe planes to form the InSbTe phase since the C atoms prevent the atomic migrations via the vacancy sites while changing the crystal structure from amorphous to metastable FCC structure. Therefore, it is plausible that the phase transformation needs more energy as increasing the C concentration, and volume change of the C doped IST is reduced by about 30 % comparing the undoped IST. In addition, the resistance drift is completely prevented by the C doping, and switching speed of the C doped IST-PRAM is also not sensitive to the C doping. The reason is ascribed to the micro spherical InSb grains distributed along the bottom to the top phase change volume because switching takes place through these 7-15nm size InSb crystalline grains. In this work, we will discuss the atomic lattice image in detail and electrical performance of MLC-PRAM.

G.G.PI..3
16:00
Authors : Yong Tae Kim, Young Hwan Kim
Affiliations : Semiconductor Materials and Devices Lab. Korea Institute of Science and Technology P.O.Box 131, Cheongryang, Seoul 130-760, Republic of Korea

Resume : Carbon doped WN (C-WN) thin films have been deposited by atomic layer deposition (ALD) method and the diffusion barrier performance for Cu interconnect has been investigated. the C-WN prepared with WF6-CH4-B2H6-NH3 gas system has very low resistivity of 100 μΩ-cm, which is normally 5~7 times as low as the WN, TiN and other diffusion barrier thin films. Rutherford backscattering spectroscopy and leakage current measurement for the Cu/C-WN/inter layer dielectric (ILD)/Si interconnect structure show excellent thermal stability to prevent the Cu diffusion even at 700℃ for 30 min. Electromigration failure of the Cu interconnect obtained at an acceleration of 102 A/cm2 clearly shows that life time of the Cu/C-WN interconnect is 4 times as long as that of the Cu/TiN. The excellent life time is explained by the low film stress of the Cu interconnect. The stress measurement indicates that the Cu/C-WN/ILD/Si interconnect has the lowest film stress even at the higher annealing temperature. When high current density flows through the Cu interconnect, high tensile film stress causes voiding in the interconnect line and the stress induced voids lead to the open circuit failure. Therefore, it is plausible that the nucleation of void may be sup-pressed by reducing the film stress. We will discuss the ALD mechanism, influences of the film stress and mechanical hardness in detail.

G.G.PI..4
16:00
Authors : ILHEM. R. KRIBA1*; K. BENOUMSAAD1; A. DJEBAILI2
Affiliations : 1 Plasma Laboratory - Faculty of Sciences – Department of Physics- University of Batna- Algeria 2 Laboratory of chemistry and environmental chemistry L.C.C.E - University of Batna- Algeria,

Resume : Titanium and titanium alloys have been used in a number of applications in industry ranging from aircraft components, chemical processing facilities to gas turbine engines due to their high strength to weight ratio, high corrosion resistance and relatively high melting temperature. However, further application of titanium and titanium alloys is considerably restricted by their low surface hardness, high friction coefficient and poor wear resistance. Therefore, the surface characteristics of titanium and titanium alloys need to be improved. Thermal spray coating is one of the most common ways to improve the surface characteristics of materials. The plasma-sprayed Al2O3 and Al2O3–TiO2 ceramic coatings have been extensively used in many applications as surface coating to protect components against wear and corrosion due to their thermal, chemical and mechanical stability. Recently, nanostructured Al2O3–13 wt.%TiO2 coating demonstrate novel and attractive properties such as bond strength, toughness, abrasive wear and thermal shock resistance. In this paper, numerical model is developed using the finite volume method, based on Navier-Stokes equations and (VOF) method to simulate the impact, spreading and flattening of the Al2O3–13 wt.%TiO2 droplets impacting onto a solid surface . The model simultaneously takes into account the fluid flow and heat transfer in the liquid particle and the surrounding gas, and the heat transfer in the substrate. To understand the effect of solidification on the droplet impact dynamics and splat morphology, the simulations were run with smoothed and roughened surfaces considering different roughness magnitude. The results show a substantial build up of temperature at the surface and large temperature gradients throughout the thickness, which are due to the differences in the melting point, specific heat and latent heat of fusion of alumina and titania, as well as the difference in their particle sizes. Also, the increase in magnitude of the mean substrate roughness promotes splat instability (jetting and/or satellite break-up) and formation of radial fingers. It was also observed that the increase in general surface roughness may result in the lower spreading ratio (Dfinal / Dinitial) of thermally sprayed ceramic particles. The spreading process of a droplet is governed not only by the inertia and viscous forces, but also by the thermal contact resistance in the substrate surface.

G.G.PI..11
16:00
Authors : N.C. Zoita1, M. Braic1, V. Braic1, M. Danila2, C.E.A. Grigorescu1, C. Logofatu3
Affiliations : 1) National Institute for Research and Development in Optoelectronics, 409 Atomistilor Str., 077125 Magurele, Romania 2) National Institute for Research and Development in Microtechnology, 126A Erou Iancu Nicolae Str., 077190 Bucharest, Romania 3) National Institute for Materials Physics, 105bis Atomistilor Str., 077125 Magurele, Romania

Resume : Titanium carbide (TiC), as a member of the early transition-metal carbides, presents interesting combination of properties which are usually assigned either to metals or to ceramics. Attributes such as high hardness, chemical inertness, high melting point and wear and corrosion resistance in combination with high electric and heat conductivities make TiC very attractive for a wide area of technological applications. In this work, epitaxial TiCx films were fabricated by DC reactive magnetron sputtering of a Ti target in Ar + CH4 atmosphere on MgO(001) substrates. The influence of substrate temperature (150 °C - 800 °C) and film thickness (50 nm – 600 nm) on the structural, electrical and mechanical properties were investigated by AES, XPS, HR-XRD, micro-Raman spectroscopy, AFM, nanoindentation and Hall effect measurements. The epitaxial growth was observed for substrate temperatures as low as 150 °C, and the same epitaxial relationship was preserved over the entire range of film thickness investigated. The films grown at temperatures larger than 400 °C present electrical resistivities comparable with those of slightly substoichiometric bulk TiCx single-crystals, the lowest one, ~160 µΩ•cm, being obtained for the thinnest film deposited at the highest temperature. The films are partially subjected to compressive strain, which relaxes with increasing of the film thickness by developing low aspect ratio nanoislands/nanocolumns on their surface.

G.G.PI..13
16:00
Authors : N. C. Zoita1, V. Braic1, M. Braic1, M. Danila2, A. Kiss1
Affiliations : 1) National Institute for Research and Development in Optoelectronics, 409 Atomistilor Str., 077125 Magurele, Romania 2) National Institute for Research and Development in Microtechnology, 126A Erou Iancu Nicolae Str., 077190 Bucharest, Romania

Resume : Aluminum nitride (AlN), as one of the III-nitride materials, has some outstanding physical properties that have attracted a lot research interests. AlN exhibits interesting optical, thermal, dielectric and acoustic properties that make it suitable for various fields and applications, some of them requiring single-crystal or high crystalline quality material with specific texture. Reactive magnetron sputtering method demonstrated to be a promising candidate for fabricating highly c-axis orientated AlN films at relatively low substrate temperature. The High Power Impulse Magnetron Sputtering (HiPIMS) technique offers the possibility to better control the energy and direction of the sputtered species at the film’s growing surface due to its capability to generate high plasma densities with a high ionization degree of the sputtered particles. The film growth is assisted by an intense ion flux resulting in energic adspecies. Therefore, HiPIMS can be beneficial for growing high crystalline quality thin films at low substrate temperature. In this work, the HiPIMS technique was used for deposition of epitaxial AlN thin films on α-Al2O3 substrates in reactive atmosphere (Ar + N2) using an Al target. The effect of sputtering gas pressure (3 – 10 mtorr) and substrate temperature (100 – 600 °C) on the structural, optical and mechanical properties of AlN epilayers are investigated by HR-XRD, Auger electron spectroscopy, optical transmission, nanoindentation and AFM measurements.

G.G.PI..14
16:00
Authors : M.Balaceanu, M.Braic, A.Parau, V.Braic, C.Vitelaru, A. Vladescu
Affiliations : National Institute for Optoelectronics, 409 Atomistilor, POBox - MG 05, 077125, Magurele- Bucharest, Romania

Resume : Nanometer – scale multilayer coatings comprising alternating layers made of different metals and metallic compounds revealed a great potential to be used as protective coatings due to their excellent resistance to wear, corrosion and oxidation. In this paper, preparation and characterization of a novel type of carbide based multilayer, namely TiSiC/NiC, is discussed. The layers in the film structure were selected to produce a non-isostructural multilayer. The coatings were prepared by the cathodic arc technique in a CH4 atmosphere. Different bilayer thicknesses, ranging from 6 to 80 nm, were obtained. The multilayers were analyzed for elemental and phase composition, microstructure, morphology, modulation periodicity, mechanical properties (residual stress, hardness, adhesion) and tribological behavior (friction, wear). For comparison, TiSiC single layer coatings were also investigated. The properties of the multilayers were found to significantly depend on the bilayer period. Typical X-ray diffraction patterns for superlattice coatings (a main (111) Bragg peak surrounded by satellite peaks) were recorded for multilayers with low bilayer thicknesses. The best mechanical and tribological characteristics were obtained for the multilayers with bilayer periods of 10-16nm. As compared to the TiSiC monolayer, reduced residual stress and improved adhesion were found for the multilayers, while the highest hardness was measured to be 1.8 time the “rule of mixture” value.

G.G.P28I..22
16:00
Authors : C.N.Zoita1, M. I. Rusu1, A.E. Kiss1, M. Stchakowsky2, C.E.A.Grigorescu1,
Affiliations : 1. National Institute R&D Optoelectronics INOE 2000, 409 Atomistilor Str, PO Box MG-5, 77125 Magurele, Ilfov, Romania; 2.HoribaHORIBA Jobin Yvon S.A.S. Z.A. de la Vigne aux Loups - 5 Avenue Arago - 91380 Chilly Mazarin - France

Resume : Germanium carbide (Ge1−xCx) films are extremely attractive due to the low stress, low light absorption and good adhesion on many substrates. In addition, these films allow the band gap tunability over a wide range in conjunction with a high thermostability. Some optical, electrical and structural properties have already been reported for the Ge1-xCx films prepared by CVD, ARE, glow discharge and reactive sputtering methods.The aim of this work is to study the influence of carbon content on the properties of germanium carbide films obtained by the RF magnetron sputtering method. The films were obtained on Si(001) and quartz substrates at three deposition temperatures (2000C, 400oC and 7000C) and two substrate bias values (100 V and 300 V). A pure Ge target was used in a deposition atmosphere consisting of a mixture of Ar and CH4, at different partial pressure ratios. The films were analyzed by quantitative AES for the elemental composition, XRD for structural characterisation, AFM for surface morphology, mechanical profilometry for thickness and film stress measurements. Optical investigations (UV-Vis-NIR, FTIR, and Raman spectroscopies as well as spectroscopic ellipsometry) and Hall mobility measurements were also carried out. The films with low Ge content present a reduced crystalline quality, the high deposition temperature promotes growth of larger grains, while higher methane partial pressures determine the reduction of the observed grain size. The ellipsometry measurements show evidence of strong substrate dependency of optical properties of the films. Germanium carbide films with tuned properties can be obtained by a careful selection of combinations of substrates and deposition parameters.

G.G.PI..23
16:00
Authors : Stanislav Novak (1), Rudolf Hrach (1, 2), Martin Svec (1)
Affiliations : (1) Department of Physics, Faculty of Science, J. E. Purkinje University, Ceske mladeze 8, 400 96 Usti nad Labem, Czech Republic; (2) Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, V Holesovickach 2, 180 00 Prague 8, Czech Republic

Resume : The paper presents a novel very efficient tool to research morphological properties of various composite structures. It focuses on the composites/nanocomposites that are created by metal particles (e.g. Ti) in a dielectric (e.g. Carbon-containing) matrix. Nevertheless, the results could be used for other two-phase systems, too. Computer experiments are used for morphological analysis both homogeneous and graded composite/nanocomposite films. The particles are assumed to be more or less randomly distributed in the matrix. A low metal volume fraction is supposed. The hard-sphere method for generation of the composite structures is used. The Voronoi tessellation was chosen as the very efficient method of mathematical morphology to describe the morphology. It is able to describe three-dimensional composite structure morphology using just one two-dimensional section in the given structure. To evaluate the disorder degree of the structure, a scalar measure is introduced. Results for the homogeneous and graded composite/nanocomposite structures are presented. It is shown that the scalar measure gives the possibility to precisely evaluate the disorder degree of the composite structures. The sensitivity of the method is very well and its noise is low. The method developed is section-independent. The computer tool enables a subsequent analysis of electrical properties of the films and their dependence on the morphology.

G.G.PI..25
16:00
Authors : M. Braic, M. Balaceanu, A. Vladescu, C.N. Zoita, V. Braic, A.Parau, M. Dinu
Affiliations : National Institute for Optoelectronics, 409 Atomistilor Str., 077125 Magurele-Bucharest, Romania

Resume : Multi-principal-element (CuSiTiYZr)C coatings were prepared by co-sputtering of pure Cu, Si, Ti, Y and Zr targets in an Ar + CH4 atmosphere, for different CH4/(CH4 + Ar) flow rate ratios (0.25; 0.35; 0.50). The films were analyzed for elemental and phase composition, crystalline structure, morphology, mechanical characteristics, corrosion resistance and tribological performance. Ternary (TiZr)C coatings were also examined for comparison. The (CuSiTiYZr)C coatings were found to be amorphous, whatever the CH4/(CH4 + Ar) ratio. For all the coatings, an increase in the carbon content led to an improvement of corrosion resistance, mechanical and tribological film characteristics, mainly due to the formation and development of an amorphous free-carbon phase. The (CuSiTiYZr)C coatings exhibited superior corrosion and wear behaviour, when comparing to (TiZr)C reference coatings with similar carbon content. The highest hardness (29.5 GPa), the lowest friction coefficient (∼0.15) and the best wear-corrosion resistance were measured for the (CuSiTiYZr)C coating with carbon/metal ratio of about 1.3 (CH4/(CH4 + Ar) flow rate = 0.50).

G.G.PI..26
16:00
Authors : Mariana BRAIC, Nicolae-Catalin ZOITA, Mihaela DINU, Iulian PANA, Anca PARAU
Affiliations : National Institute for Optoelectronics, 409 Atomistilor Str., Bucharest, Romania

Resume : Multi-principal-element (AlCrNbSiTi)C coatings were prepared by co-sputtering of pure Al, Cr,Nb,Si and Ti targets in an Ar + CH4 atmosphere, at two different CH4/(CH4 + Ar) flow rate ratios (0.05; 0.1). The films were analyzed for elemental composition, crystalline structure, morphology, mechanical characteristics and tribological performance. Ternary (TiSi)C coatings were also examined for comparison. The (AlCrNbSiTi)C coatings exhibited superior corrosion and wear behaviour, when comparing to (TiSi)C reference coatings with similar carbon content. The highest hardness (22 GPa), the lowest friction coefficient (∼0.1) and the best wear-corrosion resistance were measured for the coating with the highest carbon/metal ratio.

G.G.PI..29
16:00
Authors : N.Radić1, K. Salamon2, M. Očko2, I. Bogdanović-Radović1, S. Bernstorff3
Affiliations : 1Rudjer Boskovic Institute, Bijenicka 54, Zagreb, Croatia; 2Institute of Physics, Bijenicka 46, Zagreb, Croatia; 3Elettra, Basovizza, Italy

Resume : Beside being already used in microelectronics, the TaxN thin films hold promise to be applied in certain superconducting devices, as well. The TaxN thin films for that purpose are usually deposited on sapphire, or on SiO2 in order to decrease the cost of a final product. Here we report an interim investigation of the thin TaxN films prepared by reactive magnetron deposition in a wide range of composition deposited on SiO2. Pure tantalum target and Ar + N2 working gas were used. Films (cca 100 nm) were deposited at room temperature and 550 degC, respectively. A selected samples deposited at room temperature were subsequently annealed at intermediate temperatures in a protective atmosphere. The chemical composition of the films was determined by ERDA (0.5

G.G.PI..31
16:00
Authors : G. Abadias1, I.A. Saladukhin2, V.V. Uglov2, S.V. Zlotski2, S.N. Dub3, G. N. Tolmachova4
Affiliations : 1Institut P’, Poitiers, France; 2Belarusian State University, Minsk, Belarus; 3Institute for Superhard Materials, Kiev, Ukraine; 4Kharkov Institute of Physics and Technology, Kharkov, Ukraine

Resume : The structural and phase state of hard coatings based on transition metal nitrides as well as mechanical properties can be modified by a variation of elemental composition. In the present work we investigate the structural and phase transformations in (Ti,Zr)1-x-ySixNy films depending on Si content and deposition temperature. (Ti,Zr)1-x-ySixNy films have been deposited onto Si (001) wafers by a reactive unbalanced magnetron sputtering method at the temperatures of 270 and 600°C. Ti, Zr and Si targets were co-sputtered under mixed Ar+N2 plasma discharges. Varying the RF power of the Si target from 60 to 200 W resulted in silicon concentration, x, to increase from 0.06 to 0.22 in films. Ti:Zr concentration ratio was kept constant to ~1.0. The synthesized films are the multiphase systems consisting of (Ti,Zr)N nanocrystals surrounded by X-ray amorphous SiNy matrix. When forming at 270°C the (Ti,Zr)N nanocrystals are characterized by (200) preferred orientation. Transformation of nanocrystalline structure of the films into X-ray amorphous state is observed when Si content reaches the value of 0.22. The maximum hardness values, up to 29 GPa, are observed when 0.06 ≤ x ≤ 0.09. For (Ti,Zr)1-x-ySixNy films the friction coefficient is less than for TiZrN film and values are in the range of 0.15-0.26. There is a clear tendency of wear resistance increase with x rise up to x=0.11. Correlation of the mechanical properties of the coatings with their structural state is discussed.

G.G.PI..32
16:00
Authors : D. Valerini, D. Lorenzo, L. Tapfer, and A. Rizzo
Affiliations : ENEA - Italian National Agency for New Technologies, Energy and Sustainable Economic Development - Technical Unit for Brindisi Material Technologies, Laboratory of Materials Technology (UTTMATB-TEC), Brindisi Research Center, S.S. 7 Appia km. 706, 72100 Brindisi, Italy

Resume : Recently, high-power pulsed magnetron sputtering (HPPMS) is a widely studied PVD technique, due to its potential benefits over conventional sputtering deposition. The high power of pulses applied to the target material during HPPMS processes results in high plasma densities and increased ionization rates of the sputtered species, thus producing films with high density, low content of defects, strong adhesion, good smoothness and high hardness. As a result, through the proper choice of deposition parameters, HPPMS-deposited films can exhibit enhanced properties with respect to films deposited by conventional sputtering. These properties can be exploited in several applications, like e.g. in the case of nitride films used as protective hard coatings. Here we report the HPPMS deposition of titanium aluminum nitride (TiAlN) films at different process parameters, comparing the film properties with those of TiAlN films deposited by RF magnetron sputtering. The influence of pulse peak power (up to 300 kW) and length (up to 3 ms), on structural, morphological and tribological (hardness and adhesion) properties was analyzed. X-ray diffraction measurements revealed how the different nitride phases inside the films were tuned by changing the pulse parameters, while scanning electron microscopy showed the corresponding variations in surface morphology and film section. Nanoindentation and microscratch measurements were used to evaluate the improvement in tribological responses.

G.G.PI..35
16:00
Authors : R. Vladoiu, A. Mandes, V. Dinca
Affiliations : Department of Plasma Physics, Faculty of Physics Chemistry Electronics and Oil Technology, Ovidius University, Mamaia 124, Constanţa, 900527, Romania

Resume : With the expanding use of magnesium materials in numerous new applications within the automotive and consumer goods sectors, there is currently growing interest in developing new applications. For this reason, there is a great demand for joining of Mg in composites such as carbon containing nanostructured thin films, giving rise to unique combination of properties. The aim of the present work is to achieve the controlled synthesis of pure magnesium and nanocrystalline magnesium embedded in hydrogen-free amorphous carbon (a-C) matrix. The films with compact structure and extremely smooth are prepared using the Thermionic Vacuum Arc (TVA) method in one electron gun configuration on glass and OLC 45 special substrate, demanded by industrial area. Nanostructured coatings with homogenous and dense surface without any faults (pinholes and cracks) were achieved at low temperatures to not affect the materials properties. The results of deposition conditions on the morphology, composition and wettability of the coatings were investigated in terms of Transmission Electron Microscopy (HRTEM), XPS, AFM, scanning electron microscopy with energy-dispersive X-ray detection (SEM/EDX) and free surface energy (See System). Reports on optimized coatings by a graded structure and adjusting stress level were also discussed.

G.G.PI..36
16:00
Authors : VLADOIU Rodica1, DINCA Virginia1, MANDES Aurelia1, PRODAN Gabriel1
Affiliations : 1 Dep. of Plasma Physics, Faculty of Applied Science and Engineering, Ovidius University, Mamaia 124, Constanta, 900527, Romania

Resume : Modern engineering applications demand development of hard coatings with improved wear resistance combined with low friction and high toughness. Titanium carbide is one of the most widely used hard coating materials. Interestingly, its chemical bonding is similar as transition metal showing mixed covalent, metallic and ionic characters. A wide variety of techniques have been used to synthesize TiC metal carbide thin films. Among these, a well-established technique is the Thermionic Vacuum Arc (TVA) method. This method uses an electron beam emitted by an externally heated cathode that will evaporate the anode materials, found inside a crucible. The paper reports relations between synthesis conditions, material nanostructure and thin films properties of Ti added in carbon matrix. The surface morphology, wettability and strength of the obtained TiC multifunctional thin films were investigated. The thin films were characterized using: transmission electron microscope (TEM, Phillips CM 120 ST, 100 kV) and SEE SYSTEM contact angle device. Nanocomposite coatings of obtained TiC consisting of crystalline phase embedded into an amorphous matrix constitute a multifunctional coating architecture due to its combination of properties, suitable for emerging applications in metallurgical industry, yielding an enhanced corrosion resistance.

G.G.PI..37
16:00
Authors : Ph.V. Kiryukhantsev-Korneev1, J.F. Pierson2,3
Affiliations : 1- National University of Science and Technology MISIS,Moscow 119049, Russia 2- Institut Jean Lamour, Université de Lorraine, UMR 7198, Nancy, F-54000, France 3- CNRS, Institut Jean Lamour, UMR 7198, Nancy, F-54000, France

Resume : Nanostructured nc-CrB2 and nanocomposite nc-CrB2/a-BN films were deposited by DC magnetron sputtering of CrB2 target in Ar and Ar+(10, 15, and 25)%N2 gas mixtures. The structure, chemical and phase composition of films were studied before [1]. The films were characterised by scratch-test, micro- and nanoindentation. Behaviour of films in sliding condition was investigated in “pin-on-disk” configuration. Steel and cemented carbide were used as the counter-part materials. The impact wear of films were studied by “ball-on-plate” cyclic impact machine. Three groups of tests with 103, 104, 105 cycles were performed. Abrasive resistance was estimated by calowear-tester. Rotation speed and load were varied in the experiments. Failure zones on the film surface after all tests were investigated by optical profilometry, optical and scanning electron microscopy. Results obtained show that the wear resistance of the films increased significantly with raising of nitrogen content in the films due to strong structure modification. Influence of hardness, plasticity index, resistance to the plastic deformation, adhesion strength, crack resistance on the tribological characteristics are discussed. [1] Ph.V. Kiryukhantsev-Korneev, J.F. Pierson, M.I. Petrzhik et al. Thin Solid Films 517 (2009) 2675

G.G.PI..38
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Recent advances in polymer based thin films : Yi DAN, Lenka ZAJICKOVA
08:30
Authors : Dirk Hegemann
Affiliations : Empa, Swiss Federal Laboratories for Materials Science and Technology

Resume : Plasma polymer deposition enables the controlled modification of material’s surfaces such as e.g. polymers (including textiles and fibers) at the nanoscale. Industrial applications based on plasma polymer deposition require reliable processes that can be transferred to production-scale reactors. For this purpose, both gas phase and surface processes should be well controlled during plasma polymerization. While gas phase processes are governed by the energy invested per particle (plasma chemistry), surface processes also depend on the energy flux and on the momentum transfer during film growth (plasma physics). For the deposition of a-C:H:N plasma polymers gaseous mixtures of NH3/C2H4 as well as N2/H2/C2H4 are examined using RF discharges both in a batch reactor and in a pilot plant (at low pressure). The gas composition and energy input are found to determine the incorporation of nitrogen into the hydrocarbon network, while ion bombardment during film growth supports the formation of nucleation sites, surface diffusion, chemical bond opening and cross-linking. The amine-functional group density thus depends both on gas phase and surface processes. Moderate energetic conditions favor the formation of voids during film growth due to steric hindrance of incorporated amino groups resulting in a nanoporous film structure. Such a-C:H:N films are used for the attachment of molecules (e.g. thermoresponsive PEGs enabling controlled drug release through membranes) as well as for improved adhesion (e.g. light-weight fiber-reinforced composites). Plasma polymers containing more than 2 at% of amino groups, however, undergo hydrolysis and show leaching of polyamines in aqueous environments which has to be considered for biomedical applications (e.g. tissue engineering). The remnant films (after washing the leachable products) are found to be very stable enabling for example superhydrophilic surfaces due to the remaining nanostructure.

G.G.III.1
09:30
Authors : Damien Thiry (1), Remy Francq (1,2), Maxime Guillaume (3), Jérôme Cornil (3), Rony Snyders (1, 2)
Affiliations : (1) Chimie des Interactions Plasma Surface, CIRMAP, University of Mons, Place du Parc 23, B-7000 Mons, Belgium (2) Materia Nova Research Center, Parc Initialis, Avenue N. Copernic 1, B-7000 Mons, Belgium (3) Service de Chimie des Matériaux Nouveaux, CIRMAP, University of Mons, Place du Parc 23, B-7000 Mons, Belgium

Resume : Plasma polymerization of sulfur-based molecules such as propanethiol is a promising approach to grow thiol (-SH) supporting surfaces that can serve as nucleation centers for gold nanoparticles or for the immobilization of DNA molecules. However, despite the potential of such a kind of thin films, it is still necessary to get a deeper understanding of the plasma polymerization of sulfur-based precursors. In this work, propanethiol plasma polymers (Pr-PPF) were synthesized varying the mean power (

) dissipated in the discharge in pulsed and continuous modes. The –SH density ([SH]) is measured by means of XPS combined with a recently developed derivatization method. As a function of

, nearly constant values of [SH] of the Pr-PPF are observed. This peculiar behavior is explained considering (i) mass spectrometry data revealing a similar relative concentration of condensable SH-bearing species in the plasma and (ii) similar energetic conditions at the growing film/plasma interface. On the other hand, it has been observed that the low

synthesized Pr-PPF are not chemically stable in aqueous solutions likely due to the release of trapped sulfur-based species supported by mass spectrometry measurements. In addition, DFT calculations have been employed to assist the interpretation of the experimental data. The whole set of our data allows drawing a clear picture of the growth mechanism of Pr-PPF which is essential in view of the optimization of the layers properties.

G.G.III.5
 
Recent advances in transition metal nitrides-I : Christian MITTERER, JF PIERSON
10:30
Authors : Ivan Petrov
Affiliations : University of Illinois, USA and Linköping University, Sweden

Resume : Polycrystalline TiN and related transition-metal nitride (TMN) thin films are typically deposited by reactive magnetron sputter deposition and employed as diffusion barriers in microelectronics as well as hard, wear-, and corrosion-resistant coatings in mechanical and optical applications. We use a combination of HR-XRD, TEM, HR-XTEM, AFM, and STM analyses to characterize micro- and nanostructures. We will review the fundamental film growth processes - nucleation, coalescence, competitive growth, and recrystallization - and their role in thin film microstructure evolution as a function of substrate temperature. Special attention will paid to in-situ substrate treatment by ion-irradiation and its effect on film microstructure and adhesion. Using spontaneous natural patterning processes, we show that self-organized nanostructures consisting of commensurate nanolamellae, nanocolumns, nanospheres, and nanopipes can be synthesized to further extend the range of achievable properties. All of these structures are a result of kinetic limitations and require low growth temperatures combined with low-energy (less than the lattice atom displacement potential), very high flux, ion irradiation during deposition. Quantitative information of adatom transport and surface site energies required for the models are obtained from in-situ high-temperature STM and LEEM analyses. In addition, we use classical molecular dynamics and the modified embedded atom method formalism to investigate the dynamics of atomic-scale transport and film growth on a low-index model compound surface, TiN(001). This approach allows us to gain insight in kinetics of the pathways of Ti, N, and TiNx (x = 1 – 3) adspecies on terraces and single-atom-high TiN(001) in the picosecond regime which are not accessible by state of the art atomistic experimental techniques or by static DFT calculations. We will also review recent advances in the selective use of metal ions during HIPIMS co-sputtering to extend the attainable structures and properties in metastable TMN with examples of Ti(1-x)AlxN, Ti(1-x)SixN, ad Ti(1-x)TaxN.

G.G.IV..1
11:00
Authors : G. Abadias (1), Ph. Djemia (2), L. Belliard (3)
Affiliations : 1. Institut P', CNRS-UPR 3346, Université de Poitiers, France; 2. LSPM, CNRS-UPR 3407, Université Paris 13, Sorbonne Paris Cité, France; 3. INSP, CNRS-UMR 7788, Université Pierre et Marie Curie, France

Resume : Since the pioneering materials selection concept of Holleck [1] to design multi-component hard coatings, efforts have been made to synthesize new ternary or multinary transition metal nitride (TMN)-based alloys, which offer the possibility of fine tuning the mechanical and physical properties by an appropriate choice of metal or non-metal alloying elements and by optimizing deposition process parameters. Recent ab initio calculations by Sangiovanni et al. [2] have shown that Mo and W alloying into TiN decisively induced a ductile behaviour, which corresponds to a shear modulus to bulk modulus (G/B) ratio lower than 0.5, while retaining high hardness. However, there exists little experimental evidence of such improved ductility, as the elastic properties of such metastable compounds are scarcely studied. In an effort to address this issue, we have carried out a thorough investigation of the elastic properties of various ternary TMN systems, by combining thin film growth experiments and computational modeling. Three systems will be comparatively reviewed, TiZrN, TiTaN and TaZrN, for which the valence electron concentration spans the region of interest from 9 to 10 and which corresponds as well as to iso- and non-isostructural cases. All ternary films were obtained by reactive magnetron co-sputtering in Ar+N2 atmosphere, with the composition covering the whole range from binary counterparts. The transverse and longitudinal sound velocities were determined by Brillouin Light scattering (BLS) and picoseconds acoustics (PA), while the hardness was measured by nanoindentation. The evolution with composition of polycrystalline (effective) elastic constants , deduced from BLS and PA, will be compared to that of single-crystal elastic constants cij derived from ab initio calculations (on ordered and disordered alloys with cubic structure). The influence of phase composition, crystal structure, preferred orientation and film morphology on the elastic and mechanical properties will be discussed. Rather complex variations of and elastic constants with alloy composition are reported for both TiTaN and TaZrN systems. First, the evolution of and does not reflect in a direct way the evolution of sound velocities due to the large increase in mass density as TaN fraction increases. Another important contribution arises from the change in texture and phase composition observed for TaN-rich films. Interestingly, for TaN atomic fractions ranging from 0.5 to 0.8, the formation of a nanocomposite structure, with cubic and hexagonal grains, results in enhanced hardness (>30 GPa). [1] H. Holleck, J. Vac. Sci. Technol. A 4, 2661 (1986) [2] D. G. Sangiovanni, L. Hultman, V. Chirita, Acta Mater. 59, 2121 (2011)

G.G.IV..2
 
Modeling : Valeriu CHIRITA, Stanislav NOVAK
14:00
Authors : G. Hadjisavvas1, G. Tritsaris2, C. Mathioudakis1, E. Kaxiras2, and P. C. Kelires1
Affiliations : 1 Research Unit for Nanostructured Materials Systems, Department of Mechanical and Materials Science Engineering, Cyprus University of Technology, P.O. Box 50329, 3603 Lemesos, Cyprus; 2 Department of Physics, Harvard University, Cambridge, Massachusetts02138, USA

Resume : Carbon-based materials, including diamond-like carbon (DLC), have been suggested as promising materials for solar energy harvesting. The properties of DLC may be tuned by the incorporation of transition metal atoms, either dispersed or forming nanoparticles. In a recent work [1], we studied DLC/metal nanocomposites, with metal atoms (Ag, Cu) dispersed in the matrix at substitutional sites. We used 64-atom computational cells and density functional theory (DFT) calculations. We found that metal inclusions enhance the optical absorption in the visible, but lower the sp3 fraction and thus the strength and hardness of the DLC matrix. Here, we extend these studies to the nanoparticle case. We start with metal atoms inserted in the DLC matrix interstitially, which eventually grow into larger nanocrystals. We use larger cells of 512 atoms. The initial DLC networks are generated with tight-binding calculations. The final structures with metals are relaxed with DFT and then properties are calculated. The first results indicate that the reduction of sp3 fraction is less drastic than in the dispersed case, which is beneficial for the mechanical properties. Also, the optical absorption is enhanced. By decomposing the absorption coefficient into site contributions, we aim to identify the strong absorbing atoms in the system, especially in the metal nanocrystals. [1] G. Tritsaris, C. Mathioudakis, P. C. Kelires, and E. Kaxiras, J. Appl. Phys. 112, 103503 (2012).

G.G.V..1
14:15
Authors : Bo Lü, Viktor Elofsson, Daniel Magnfält, Peter Münger and Kostas Sarakinos
Affiliations : Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83, Linköping, Sweden

Resume : Deposition of metal vapour on insulating substrates commonly proceeds in the so-called Volmer-Weber growth mode, in which isolated islands nucleate, grow in size, coalesce, form an electrically conducting network (percolation) and eventually form a continuous structure. The initial formation stages, i.e., island nucleation, growth and coalescence set characteristic length scales on the growing surface. Therefore, fundamental understanding of the dynamics of those formation stages and of their complex interplay is paramount of knowledge-based design and synthesis of thin films and nanostructures. By establishing the effect of growth conditions on the scaling behaviour of characteristic transition thicknesses, e.g., the percolation transition thickness, theoretical research has suggested the existence of two regimes; one in which growth is dominated by coalescence and a second one in which growth behaviour is determined by island growth and impingement. Here we use kinetic Monte-Carlo growth simulations and analytical expressions to derive the universal condition for the transition from one regime to another as a function of adatom arrival rate, adatom surface diffusivity and coalescence completion rate. Experimental evidence for the existence of both regimes is provided by monitoring in-situ the growth of Ag on SiO2 both by continuous and pulsed vapour fluxes. The implications of our findings for surface science and surface engineering communities are discussed.

G.G.V..2
17:00
Authors : V. Craciun1, C. Martin2, G. Socol1, D. Tanner3, and D. Craciun1
Affiliations : 1Lasers Department, National Institute for Lasers, Plasma and Radiation Physics, Magurele-Bucharest, Romania 2Ramapo College of New Jersey, NJ 3Physics Department, University of Florida, Gainesville, FL

Resume : ZrC thin films were grown on Si substrates by the Pulsed Laser Deposition technique. By changing the substrate temperature and ambient gas nature and pressure during deposition, films having a wide range of crystal grain sizes, mass densities and C/Zr ratios were obtained. We investigated the IR optical properties of ZrC films by measuring the optical reflectance from 30 cm-1 (4 meV) to 30 000 cm-1 (4 eV), using a Bruker-113v FTIR spectrometer and a Carl Zeiss microscope photometer. The resistivity values extracted from the optical data were similar to those measured using a four point probe technique. The results indicated that ZrC films exhibited high reflectivity in the mid IR range regardless of the structure and composition. Very low resistivity values of around 5×10-5 .cm and slightly lower wear rates were measured for films having the highest ratio of C/Zr, while higher hardness values were measured for films having the largest crystal grains. These excellent qualities recommend the ZrC films for applications as thermal radiators working at very high temperatures in the outer space.

G.G.VI..2
17:30
Authors : M. Alcaire, F.J. Aparicio, L. Cerdán, F. Lahoz, A. Borras, I.García-Moreno, A. Costela, A.R. González-Elipe, A. Barranco.
Affiliations : M. Alcaire; F.J. Aparicio; A. Borras; A.R. Gonzalez-Elipe; A. Barranco, nstituto de Ciencia de Materiales de Sevilla (CSIC-Universidad de Sevilla). c/Américo Vespucio 49, 41092 Sevilla, Spain. L. Cerdán; I. García-Moreno; A. Costela, Instituto de Química Fïsica Rocasolano, (CSIC),c/ Serrano 119, 28006 Madrid. Spain. F. Lahoz, Dpto. Física Fundamental y Experimental, Electrónica y Sistemas, Universidad de La Laguna. C/ Astrofísico Francisco Sanchez s/n, 38206 La Laguna.Santa Cruz de Tenerife, Spain

Resume : Remote plasma assisted vacuum deposition is a novel a versatile deposition methodology, which permits the fabrication of organic films from non-chemically polymerizable organic or organometallic molecules.[1-3] The technique is based in the effective control of the interaction between the sublimated precursor molecules and a remote glow discharge. Thus, the technique has some similarities with the vacuum deposition and the plasma polymerization processes. Once formed, the films are solid cross-linked organic structures typically insoluble in organic solvents and thermally stable at temperatures higher than the sublimation temperatures of the precursor molecules. The technique also permits the direct fabrication of microstructures and low dimensional nanostructures. The optical properties of the films (light absorption, luminescence, sensor response, etc) depend on the precursor molecules and on the particular thin film nanostructures and final composition. Examples of multifunctional films and microstructures deposited from laser dyes and other relatively complex molecules for the fabrication of photonic structures, gas sensors, optical films, lasing media and optoelectronic components will be presented and studied. [1] A. Barranco, P. Groening, Langmuir 22 (2006) 6719. [2] I. Blaszczyk-Lezak et al. J. Phys. Chem. 113 (2009) 431. [3] F.J. Aparicio et al. Adv. Mater. 23 (2011) 761.

G.G.VI..5
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09:00
Authors : D. Edstr?m, D.G. Sangiovanni, V. Chirita and L. Hultman
Affiliations : Thin Film Physics, IFM, Link?ping University, Sweden

Resume : Enhanced toughness in hard and superhard thin films is a primary requirement for present day ceramic hard coatings, known to be prone to brittle failure during in-use conditions, in modern applications. In our previous Density Functional Theory (DFT) investigations, we predicted significant improvements in the hardness/ductility ratio of several pseudobinary B1 NaCl structure transition-metal nitride alloys, obtained by alloying TiN or VN with NbN, TaN, MoN and WN [1, 2]. The initial calculations, which were carried out on model, highly ordered configurations with Cu-Pt ordering on the cation sublattice, reveal that the electronic mechanism responsible for toughness enhancement stems from the high valence electron concentration (VEC) of these alloys, and ultimately allows a selective response to tetragonal and trigonal deformations. Recently, these results have been validated experimentally. Single-crystal V0.5Mo0.5N/MgO(001) [3] and V0.6W0.4N/MgO(001) [4] alloys, were grown by dual-target reactive magnetron sputtering, together with VN/MgO(001) and TiN/MgO(001) reference samples. The V0.5Mo0.5N films exhibit hardness >50% higher than that of VN, and, in contrast to nanoindented VN and TiN reference samples, which suffer from severe cracking, the V0.5Mo0.5N films do not crack. No ordering on the cation sublattice is observed in the V0.5Mo0.5N films, however, the onset of W ordering on adjacent {111} planes of the metal sublattice, is observed in V0.6W0.4N alloys. Here we present new DFT results, which address the issue of lattice ordering effects on the mechanical properties of these pseudobinary alloys. Our investigations concentrate on V0.5Mo0.5N, V0.5W0.5N, Ti0.5Mo0.5N and Ti0.5W0.5N alloys obtained by alloying TiN and VN with WN and MoN. Our calculations, carried out for structures with increasing levels of disorder, reveal that while the degree of electronic structure layering, i.e. the formation of alternating layers of high and low charge density upon shearing, becomes less pronounced in disordered configurations, the overall VEC effect is not affected. The essential feature in the disordered alloys, as initially predicted for highly ordered configurations, remains the increased occupancy of electronic d-t2g metallic states, which allows the selective response to tensile/shearing stresses, and explains the enhanced toughness confirmed experimentally for V0.5Mo0.5N films. [1] D. G. Sangiovanni et. al. Phys. Rev. B 81 (2010) 104107. [2] D. G. Sangiovanni et. al. Acta Mater. 59 (2011) 2121. [3] H. Kindlund et. al. Appl. Phys. Lett. Materials, 1 (2013) 000000. [4] H. Kindlun et. al. J. Vac. Sci. Technol. A 31 (2013) 040602.

G.G.VII..2
09:15
Authors : A. Rizzo, L. Mirenghi, D. Valerini, R. Terzi, L. Tapfer
Affiliations : ENEA - Italian National Agency for New Technologies, Energy and Sustainable Economic Development - Technical Unit for Brindisi Material Technologies, Laboratory of Materials Technology (UTTMATB-TEC), Brindisi Research Center, S.S. 7 Appia km. 706, 72100 Brindisi, Italy

Resume : A comprehensive study on the influence of the Al content on TiAlN coating microstructure and related mechanical and tribological properties are presented. A layered structure of TiAlN and AlN is obtained applying an average power density of 2.468 W/cm2 and 1.234 W/cm2 to a TiAl and Al target respectively, by the RF modulated pulse power. X-ray diffraction reveals fcc single-phase coatings at low Al contents and dual-phase or hcp phase at higher Al contents. As-deposited TiAlN and TiAlN/AlN film compositions are determined by X-ray Photoelectron Spectroscopy (XPS). The single TixAl1-xN film has x = 0.36 which remains unchanged even in the multilayer. The Ti 2p 3/2 peak can be fitted with two components, whose relative areas vary along the sample depth, and are ascribed to the fcc and hcp phase of the ternary compound. The peak at lower B.E. is shifted respect to the TiN peak at about 455.3 eV. The second peak is associated to a ternary structure like hcp-TiAlN. The presence of two different chemical states on Ti 2p does not induce any variation on Al 2p and N 1s spectra. Hardness measurements show high values for x=0.36, decreasing with increasing Al to values of 17 GPa at x=0.76. Friction coefficients are around 1.5 at room temperature but decrease significantly at higher temperatures to 0.88 at 700 °C. This investigation clearly shows the relations between coating composition and the resulting structure explains their mechanical and tribological properties.

G.G.VII..3
11:15
Authors : M. Scardamaglia 1, F.J. Aparicio Rebollo 1, C. Struzzi 2, P. Mudimela 4, J.-F. Colomer 4, L. Gregoratti 2, L. Petaccia 2, R. Snyders 1, and C. Bittencourt 1
Affiliations : 1 Chemistry of Interaction Plasma Surface (ChIPS), University of Mons, Belgium; 2 Elettra Sincrotrone Trieste S.C.p.A., AREA Science Park, Italy; 3 Institut des Mat?riaux Jean Rouxel, Universit? de Nantes, CNRS, Nantes, France; 4 Research Centre in Physics of Matter and Radiation, University of Namur, Belgium;

Resume : The electronic properties of sp2 carbon nanostructures are very sensitive to local perturbations, such as surface charges and adsorbed gas molecules, so that the grafting of functional groups in a controllable way has been proposed as a feasible reproducible solution for band gap engineering and controllable doping, in order to exploit and tailor the extraordinary properties of these materials. Plasma-based functionalization methods have the advantage to be solvent-free, time efficient and flexible. Within this context, we will discuss the functionalization of vertical aligned carbon nanotubes (v-CNTs) via nitrogen plasma treatment. Valence band (UPS) and scanning X-ray photoelectron spectromicroscopy (SPEM) measurements were performed at ELETTRA Synchrotron. The creation of defects induced by ions drives the grafting of nitrogen species (pyridinic, pyrrolic and graphitic) on the CNTs. A depth of functionalization up to 4 μm was evaluated by SPEM, beyond which the properties of the v-CNTs remain unperturbed. Furthermore, an intriguing different behavior of the grafting at the CNT tips with respect to the sidewalls was observed. This indicates a different reactivity of the CNT tip, where the presence of natural defects may be involved in different bonding formations between carbon and nitrogen. The effect of the temperature has been evaluated both during the plasma treatment and with post synthesis annealing, showing variations in the ratio between the nitrogen species.

G.G.VIII..3
11:30
Authors : Vladimir Baryshevsky 1, Nikolai Belous 1, Alexandra Gurinovich 1, Evgeny Gurnevich 1, Polina Kuzhir 1, Sergey Maksimenko 1, Pavel Molchanov 1, Mikhail Shuba 1, Tommi Kaplas 2, Yuri Svirko 2
Affiliations : 1 Research Institute for Nuclear Problems, Belarusian State University 2 University of Eastern Finland

Resume : We report high current density explosive electron emission from a copper cathode with diameter of 50 mm with pre-deposited pyrolytic carbon (PyC) films being from 70 to 150 nm thick. In the diode configuration, we demonstrate the current density as high as 300A/cm2 under applied voltage below 400 kV. The Raman measurements reveal that the PyC film survives after 7 shots. In order to study the cathode degradation we compared optical microscope images of the cathode before and after shots. We observed that the pre-deposited PyC film cathode prevents copper evaporation and oxidation. This property ensures a higher explosion emission stability and longer lifetime of the PyC/Cu-cathodes in comparison with conventional graphitic/Cu ones. Our results show that PyC/Cu cathodes are most promising for applications that require electric field strengths from 50 to 60 kV/cm.

G.G.VIII..4
13:30
Authors : A. Aghdaie 1, H. Haratizadeh 1, S.H. Mousavi 1,2
Affiliations : 1. Physics Department, Shahrood University of Technology, Shahrood, Iran 2. INM– Leibniz Institute for New Materials, 66123 Saarbrücken, Germany

Resume : Undoped, Cu and Mn doped aluminium nitride (AlN) nanostructures were synthesized using a chemical vapour condensation (CVC) method. The raw materials were a mixture of Al and NH4Cl powder with different weight ratios and Cu and Mn powders, which were used as a dopant. Field emission scanning electron microscopy (FE-SEM) results showed different nanostructures, including nanowires and nanoparticles of different sizes. Photoluminescence (PL) spectroscopy of as-prepared samples show intense peaks in red, blue-green and blue regions in the Mn doped, Cu doped and undoped samples, respectively. These results are important for optoelectronical applications.

G.G.PII..9
13:30
Authors : M. Scardamaglia 1, B. Aleman 2, M. Amati 2, C. Ewels 3, P. Pochet 4, N. Reckinger 5, J.-F. Colomer 5, T. Skaltsas 6, N. Tagmatarchis 6, R. Snyders 1, L. Gregoratti 2, and C. Bittencourt 1 and C. Bittencourt 1
Affiliations : 1 Chemistry of Interaction Plasma Surface (ChIPS), University of Mons, Belgium; 2 Elettra Sincrotrone Trieste S.C.p.A., AREA Science Park, Italy; 3 Institut des Matériaux Jean Rouxel, Université de Nantes, CNRS, Nantes, France; 4 Laboratoire de simulation atomistique (L_Sim), SP2M, INAC, CEA-UJF, Grenoble F-38054, France; 5 Research Centre in Physics of Matter and Radiation, University of Namur, Belgium; 6 Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constaninou Avenue, 116 35Athens, Greece;

Resume : Achive the fine tuning of the graphene electronic properties is one of the main challenges for optimal fabrication of graphene-based nano-devices. Notably the low carrier density in pristine graphene at the Fermi level means that charge carrier doping is very attractive for nanoelectronics applications. Among these, the introduction of nitrogen atoms into the hexagonal carbon lattice of graphene has attracted interest in the recent years. Within this context, we present an experimental report that combines scanning photoemission microscopy analysis with in-situ nitrogen ion casting on suspended graphene. Nitrogen doping was performed by N2 ions bombardment in ultra-high vacuum. Inclusion of up to 20 at. % nitrogen can be reached through this clean technique with absence of oxygen species in the final product, while maintaining a largely sp2-carbon network. The inclusion was observed by scanning X-ray photoelectron microscopy which can be used to follow the evolution of nitrogen species: pyridinic, graphitic, and pyrrolic, at different doping stages and annealing temperatures. Variations in the ratio between sp2 nitrogen species was observed for increasing treatment time; annealing results in quenching of the sp3 component, suggesting graphitic nitrogen as the most thermal stable species. The occurrence of graphitic species together with the absence of pyrrolic is indicative of N-incorporation into a hexagonal graphene-based lattice.

G.G.PII..12
13:30
Authors : Yuda Zhao, Yang Chai
Affiliations : Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Hong Kong.

Resume : Ag thin film is an efficient surface enhanced Raman spectroscopy (SERS) substrate because its quality factor of localized surface plasmon resonance (LSPR) is much larger than other materials, e.g., 10 times larger than that of Au at the wavelength of 500 nm. However, the chemical instability of Ag in ambient environment significantly degrades the SERS properties, and hinders the practical applications. Although conventional protective structures (e.g., silica and alumina barrier) can inhibit the Ag corrosion in ambient, they usually have large light absorption and reduce the plasmonic enhancement. In this work, we transfer monolayer graphene onto Ag SERS substrate, on one hand, to protect Ag from corrosion, and on the other hand, to prevent the photo-induced damages (photocarbonization, photobleaching and metal-catalyzed reaction) on the probed molecules. Firstly, we comparatively study morphological characteristic of the Ag SERS substrates with and without graphene protective barrier, revealing high corrosion-resistance of monolayer graphene to the oxidizing gas and liquid. We further demonstrate the graphene coated Ag thin films as stable SERS substrate. After 35-day exposure in air, the graphene coated Ag thin film maintains high SERS sensitivity. Secondly, we systematically study the resistance to photo-induced damages with graphene barrier. Our results show that Ag SERS substrate with graphene coating significantly improves the SERS reproducibility, and simultaneously inhibits metal-catalyzed reaction. In addition, the graphene layer can form strong interaction with the probed R6G molecules through π-π bonding stack, reducing the possibility of photo-induced desorption. In summary, our results show that graphene coating on Ag substrate effectively enhances the resistance to the corrosion and photo-induced damages.

G.G.PII..17
13:30
Authors : Han Gil Na, Hong Yeon Cho, Yong Jung Kwon, Hyoun Woo Kim*
Affiliations : Department of Materials Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-Gu, Seoul, 133-791, Korea

Resume : We have fabricated reduced graphene oxide (RGO) and functionalized them with metal nanoparticls. To obtain uniform metal-RGO sheets, the supernatant was centrifuged to remove small graphene pieces and water-soluble by product, repeatedly washed with distilled water until the pH = 7. Due to their outstanding physical and chemical properties, graphene and its derivatives have attracted tremendous attention for both fundamental science and possible technological applications. RGO can be efficiently prepared by reducing (i.e. annealing) graphene oxides. Although RGO has irreversible defects, disorder and residual functional groups, it exhibits a sufficient conductivity. Transmission electron microscopy results exhibited the deposition of metal nanoparticles on RGOs. The NO2 gas sensing test was carried out to demonstrate the ability of the metal functionalization to attain the higher sensitivity than bare RGO sheet. We have discussed the possible mechanisms for improvement of the sensing properties by metal-functionalization. We suppose that spillover effect induced by metal nanopartitcles play a significant role in enhancing the sensing properties.

G.G.PII..18
13:30
Authors : S. M. Iordache, A.-M. Iordache, A. Balan, L. Popovici, Ioan Stamatin*
Affiliations : University of Bucharest, Faculty of Physics, 3Nano-SAE Research Center, Atomistilor 405, P.O. Box 38, Bucharest-Magurele, Romania, 077125 *Corresponding author: istarom@3nanosae.org

Resume : We report the codeposition of three conjugated polymers, with π molecular orbitals delocalized along the polymer chain, (polyaniline, polypyrrole, polythiophene) and poly-1,4-dichloro-2-butyne from suitable monomers on silicon substrate by plasma polymerization that is aiming to identify the range of negative differential resistance (NDR) behavior in I-V characteristics and their correlation with the conduction mechanisms and space charge distribution. The deposited thin films were characterized by UV-VIS (e.g. band gap), FT-IR-Raman (e.g. structural identification of the structural units) spectroscopy and AFM/STM topography. The polyaniline-poly-1,4-dichloro-2-butyne and polythiophene-poly-1,4-dichloro-2-butyne systems show NDR ranged in 0.5 – 1 V, values that are close to requirements in designing of smart card devices based on tunnel diodes.

G.G.PII..22
13:30
Authors : W. W. Wang1,2, P. Le Rendu1, Y. Dan2, T. P. Nguyen1*
Affiliations : 1Institut des Matériaux Jean Rouxel, University of Nantes, CNRS, 2 rue de la Houssinière, 44322 Nantes, France 2State Key Laboratory of Polymer Materials Engineering of China (Sichuan University), Polymer Research Institute of Sichuan University, Chengdu 610065, China

Resume : Composites made by polymer blending is an attractive alternative to produce materials with tailored properties intended to industrial applications. Chitosan and polylactide (PLA) are both biodegradable and biocompatible polymers with potential use in medical applications. Their combination to provide new materials with controllable composition and properties is very interesting and promising for specific applications in the medical field. In this work, we present the synthesis of the blends for fabrication of nanocomposite thin films and their characterization by optical spectroscopies. Because of their different polarities, the polymers need to be dissolved in a solvent blends in defined conditions for obtaining a homogeneous solution. We have successfully established a ternary phase diagram using chloroform, acetic acid and water and defined the conditions for obtaining controlled compositions of PLA/chitosan composites. Analysis of the optical spectra of PLA, chitosan and their composites shows that the structure of the polymers is preserved in their blends. This observation suggests that chitosan is fully incorporated to PLA without significant interactions. Degradation study of the blends under prolonged UV irradiation reveals that chitosan is more stable in composites but is decomposed before PLA .

G.G.PII..23
13:30
Authors : S.D. Stoica, S. Vizireanu, C.R. Luculescu, B. Mitu, G. Dinescu
Affiliations : National Institute for Laser, Plasma and Radiation Physics, Magurele, 077125, Romania

Resume : Nanostructured carbon materials based on graphene are among the most studied materials nowadays, due to interesting properties which allow their utilization in various applications. Previously, we have developed a method for carbon nanowalls (CNW) growth based on downstream deposition from an expanding radiofrequency argon plasma beam discharge injected with acetylene in the presence of hydrogen. So-called ?standard? conditions were defined as: RF power = 300 W, Ar:H2:C2H2 = 1050:25:1 sccm, pressure = 1 mbar, distance from the injection = 5 cm, substrate temperature = 700 ?C. The present study aims to investigate the effect of the nozzle geometry (diameter 2-16 mm) on the material characteristics and to correlate them with the plasma species present during the synthesis process. The main investigation technique was Scanning Electron Microscopy (SEM) for revealing the obtained morphologies and structures, in combination with statistical processing of SEM images for determination of specific length/width ratio of individual CNW. The plasma process was analyzed regarding the excited species by Optical Emission Spectroscopy (OES) performed both at the injection level and on the deposition level. We show that either CNW, or combined nanofibers/nanowalls architectures with various aspect ratios can be obtained, and the OES technique may provide information which allows a correlation between the material characteristics and the internal plasma parameters.

G.G.PII..24
13:30
Authors : V. Satulu(1), B. Mitu (1), V. Ion(1), I. Sarbu(2), D. Pelinescu (2), G. Dinescu (1)
Affiliations : (1) National Institute for Laser, Plasma and Radiation Physics, Magurele, 077125, Romania (2) University of Bucharest, Centre for Research, Education and Consulting in Microbiology, Genetics and Biotechnology (MICROGEN),, Bucharest, Romania

Resume : Organic-inorganic nanocomposites have found extensive range of application in various fields, from energy storage to catalysis or biomedical materials. In particular, metallic nanoparticles embedded in polymeric matrices are of high interest for biomedicine. Plasma polymerized polyethylene glycol films present antifouling properties and low water solubility, while the silver particles are well known for their antimicrobial effect as well as for generation of plasmon resonance effect. This work proposes the deposition of polyethylene glycol ?silver (PEG-Ag) nanocomposites with tunable composition by using low pressure RF plasma system. The study aims the obtainment of a synergistic effect by means of proper control of the composition and density of each component through experimental parameters. The morphology, chemical composition and optical properties of the material were determined by means of Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Spectroscopic ellipsometry, respectively. The antimicrobial effect against various strains as S. aureus, E. coli and C. albicans was demonstrated.

G.G.PII..25
13:30
Authors : Eva Kedronova1, Lenka Zajickova2, Dirk Hegemann3, Miroslav Michlicek2, Anton Manakhov2, Milos Klima2, Eliska Mikmekova4
Affiliations : 1 Department of chemistry, Faculty of Science, Masaryk University Brno, Czech Republic; 2 Department of Physical Electronics, Faculty of Science, Masaryk University Brno, Czech Republic; 3 EMPA St. Gallen, Switzerland; 4 Institute of Scientific Instruments, Academy of Sciences of the Czech Republic, Brno, Czech Republic

Resume : Electrospinning is commonly used for preparation of polymer nanofibers but the application of the nanofibers usually requires an additional surface treatment. Plasma enhanced chemical vapor deposition (PECVD) is a versatile technique used for surface modification and it is interesting to test it also for highly porous materials such as electrospun nanofibers. Organic/inorganic composites were prepared by PECVD of organosilicon plasma polymers deposited on PVA and PA6 electrospun nanofibers from HMDSO/Ar mixtures. Low pressure RF discharges with capacitive coupling and by cold RF plasma multi-jet working at atmospheric pressure were used. Deposition conditions were varied to get samples with different structure and wettability and their influences on chemical composition of the resulting layers were investigated by IR spectroscopy and the XPS. The values of the WCA were strongly influenced by both chemical composition of deposited layers and overall surface structure. Significant variations in microstructure of resulting composites were revealed by AFM and SEM analysis of composites prepared by different plasma sources.

G.G.PII..26
13:30
Authors : D.V. Savchenko(1),(2), B.D. Shanina(1), E.N. Kalabukhova(1), A.A. Sitnikov(1), V.S. Lysenko(1), V.A. Tertykh(3)
Affiliations : (1)V.E. Lashkaryov Institute of Semiconductor Physics, NASU, Kyiv, 03028, Ukraine (2)Institute of Physics, AS CR, Praha 8, 18221, Czech Republic (3)A.A. Chuiko Institute of Surface Chemistry, NASU, Kyiv, 03164, Ukraine

Resume : Fumed silica A-300 was carbonized by means of pyrolysis of CH2Cl2. The obtained initial SiO2:C nanopowders of black color (d~14-16 nm, carbon concentration 7 wt%) subjected to the oxidation and passivation treatment were studied by electron paramagnetic resonance (EPR) at 4.2-400 K. Two EPR signals of Lorentzian lineshape with nearly equal g-factors and different linewidth were observed in all samples. The two-component EPR spectrum was explained by the presence of the C clusters of different sizes resulting in EPR line of different linewidth due to the spin exchange interaction between paramagnetic centers. The intensive narrow EPR signal was attributed to the carbon related defect (CRD) with non-localized electron hopping between neighboring C-dangling bonds. From the temperature dependence of resonance field position of the CRD EPR signal, caused by exchange interaction between conduction electrons and localized spin system, the parameters of the localized spin system has been determined in oxidized and passivated samples. It was supposed that the conduction electrons are coupled with electrons localized at interface defect. The observed peaks in temperature dependence of the conduction electron EPR signal integral intensity at 200-440 K was explained by ejection of electrons from the confinement energy levels of carbon quantum dots when the temperature become comparable with the confinement energy. The work supported by STCU №5513 and SAFMAT CZ.2.16/3.1.00/22132 projects.

G.G.PII..29
13:30
Authors : D. Gallach1,2, L. Le Brizoual3, N. Gautier4, M.D. Ynsa Alcalá1,5, V Torres Costa1,2, JP Landesmann6, M Manso Silván1,2
Affiliations : 1 Departamento de Física Aplicada, Universidad Autónoma de Madrid, Madrid, Spain 2 Instituto de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, Madrid, Spain 3 Institut d'Electronique et de Télécommunications de Rennes - UMR 6164. Université de Rennes 1.35042 Rennes, France. 4 Institut de Materiaux de Nantes, UMR 6502, Nantes , France. 5 Centro de Microanálisis de Materiales, Universidad Autónoma de Madrid, Madrid, Spain. 6 Institut de Physique de Rennes, UMR 6251, Rennes , France.

Resume : ZnO- porous Silicon (ZnO-PSi) nanostructured composite films have been prepared exploiting the low wettability of freshly prepared anodized porous silicon towards ZnO sols based on zinc acetate. Upon thermal annealing the ZnO sols diffuse through the columnar PSi and give rise, as evidenced by transmission electron microscopy, to a surface decorated by hexagonal ZnO crystallites. Relevantly, at temperatures as high as 800ºC the crystallites become void presumably as an effect of C impurities. In fact, X-ray photoelectron spectroscopy and C-resonant Rutherford backscattering spectroscopy show that Integrated C species are observed to continuously diminish for increasing annealing temperatures. The so formed structures present relevant optical properties as derived from ellipsometry measurements, which could be useful for the design of optical filters and other interferential or angular dependent optical devices.

G.G.PII..30
13:30
Authors : I.C. Vasiliu1, I. Ionita2, A. Matei3, M.Elisa1, R. Iordanescu1, I. Feraru1, A. Emandi1
Affiliations : 1INOE 2000 - National Institute for Optoelectronics, 409 Atomistilor Str., Magurele RO-077125, Bucharest, Romania, icvasiliu@inoe.inoe.ro 2UB - University of Bucharest, 405 Atomistilor Str., Magurele RO-077125, Bucharest, Romania 3INFLPR - National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Street, Magurele, RO-077125 Bucharest, Romania

Resume : We investigate the SHG behavior of SiO2-P2O5 thin films doped with some polyazo dye molecules comprising D – donor (NH2) ant A – acceptor (NO2) moieties, which change under illumination with visible light. Our data show that photoisomerisation, phototautomerization reactions and light-induced polar orientation are dependent on the molecular structure of the guest molecules. Polar structure and molecular size, as well as the chemical structure of SiO2-P2O5, are the dominant parameters that determine SHG. Two forms of azo-based dyes ( trans ant cis forms) are responsible for the interaction with irradiating laser light and forming an anisotropic structure inside the SiO2-P2O5 /dye thin films

G.G.PII..32
13:30
Authors : P.A.Karaseov1, A.I.Titov1, M.V.Mishin1, V.S.Protopopova2, A.Ya.Vinogradov3, O.A.Podsvirov1, P.G.Gabdullin1, E.N.Shubina1
Affiliations : State Polytechnic University, St. Petersburg, Russia; Aalto University, Helsinki, Finland; Ioffe Institute, St. Petersburg, Russia

Resume : It is well known that different varieties of carbon-based nanostructures demonstrate facilitated field-induced electron emission, even if they have no high-aspect-ratio surface morphology elements, such as sharp tips or ribs. Macroscopic properties of DLC films strongly depend on relative content of sp3- and sp2-hybridized carbon bonds and hydrogen content. The quality of DLC films and hence their properties can be tailored by tuning the ratio of sp2/sp3 carbon atoms and stress in the films, both of which can be changed by doping metals or non-metals in DLC matrix. In this contribution we report growth and study of properties of sandwich structures comprising layers of both Ni-C nanocomposite and α-C:H layers on (100) crystalline silicon substrates. α-C:H layers were grown using RF plasma of methane and methane-hydrogen mixtures. Process of deposition of α-C:H layers was carried out in the PECVD method. ncNi-carbon layers were grown by the MOCVD technique using bis-(ethylcyclopentadienyl) nickel (EtCp)2Ni as a precursor. The deposition process was carried out in low-pressure tube silica reactor in the temperature range 350-650°C. Nanocomposite layers contained 10-20 nm Ni particles presumably coated by nickel carbide shells were obtained. Results of investigation of DLC films and different sandwich structures by AFM, SEM, XPS and other techniques will be presented. This work was supported by RFBR grants № 12-08-01197 and 13-02-92709.

G.G.PII..33
13:30
Authors : P.A.Karaseov, A.I.Titov, K.K.Karabeshkin
Affiliations : State Polytechnic University, St.Petersburg, Russia

Resume : Structural damage formation in Si irradiated at room temperature by atomic (P+) and molecular (PF4+) ions is experimentally studied in a wide energy range (0.6-3.2 keV/amu). Strong molecular effect, caused by overlapping of collision cascades created by atoms comprising molecular ion, is revealed close to the sample surface in all cases considered. Theoretical assessments of depths where nonlinear processes are possible have shown good agreement with experimental data. Primary defect generation enhancement in the vicinity of Si surface is estimated about factor of 5. This work was supported by RFBR (grants 13-08-00666 and 14-08-01256).

G.G.PII..34
13:30
Authors : Š. Meškinis, A. Čiegis, A. Vasiliauskas, K. Šlapikas, S. Tamulevičius, G. Niaura
Affiliations : Institute of Materials Science of Kaunas University of Technology, Savanorių 271, 50131 Kaunas, Lithuania

Resume : Diamond like carbon (DLC) is a metastable form of the amorphous carbon consisting from the sp2 bonded (graphite like) carbon clusters embedded into the sp3 bonded (diamond like) carbon matrix. DLC films remains under considerable interest of the researchers due to the high optical transmittance in visible light and IR ranges, high hardness and wear resistance, corrosion resistance, biocompatibility. Additional control of DLC properties can be achieved by doping with different metals. Particularly surface plasmon resonance effect was observed in group I metal containing DLC films. In addition good hemocompatibility and antibacterial properties were reported for group I metal containing DLC films. Taking into account interesting properties of DLC films mentioned above group I metal containing DLC films can become interesting material for fabrication of the advanced plasmonic biomedical sensors. In present study copper containing diamond like carbon films (DLC:Cu) films were deposited by using reactive high power pulsed magnetron sputtering. High power pulsed magnetron sputtering is novel high density plasma deposition method. High plasma density of the high power pulsed magnetron sputtering is advantageous for deposition of DLC films containing high amount of sp3 bonded carbon. Effects of the acetylene and argon gas flow ratio as well as pulse current density were studied. The dependence of the optical properties of DLC:Cu films on structure and composition was investigated.

G.G.PII..35
13:30
Authors : Asta Tamulevičienė*, Vitoldas Kopustinskas*, Gediminas Niaura**, Šarūnas Meškinis*, Sigitas Tamulevičius*
Affiliations : *Institute of Materials Science of Kaunas University of Technology, Savanorių Ave. 271, LT-50131 Kaunas, Lithuania **Center for Physical Sciences and Technology, Institute of Chemistry, A. Goštauto 9, LT-01108 Vilnius, Lithuania

Resume : Amorphous diamond like carbon films can be modified by introducing doping compounds during deposition process. As potential candidates for modification usually Si, O, N, Ag, Cu are used. In case of Si, O and N incorporation, organosilicone compounds such as hexamethyldisiloxane (HMDSO) and hexamethyldisilazane (HMDSN) are used. Incorporation of SiOx gives better adhesion and optical properties (transparency, optical band gap) of the films. Using HMDSN one can form silicon carbonitride thin films with high hardness, low friction coefficient, etc. Even though these films show interesting properties, the structure of these films employing multiwavelength Raman scattering was not investigated. In the current research thin a-C:H:SiOx and a-C:H:SiN films were deposited on crystalline silicon and fused silica from HMDSO and HMDSN compounds respectively, using closed drift ion beam source and different ion beam energy. The structure of these films was studied employing multiwavelength (325 nm – 785 nm) Raman analysis. From the Raman spectra analysis, the characteristic parameters such as the positions of D and G peaks, D/G peak ratio as well as dispersion of G peak showing topological disorder of sp2 phase in doped a-C:H films were determined. Optical properties of the films were analysed versus composition and structure as well as doping conditions during deposition.

G.G.PII..36
13:30
Authors : I. Karbovnyk (1), P.Savchyn (1), A. Huczko (2), M. Cestelli Guidi (3), C Mirri (3), A. I. Popov (4,5)
Affiliations : (1) Dept of Electronics, Ivan Franko National University of Lviv, 79005, Lviv, Ukraine, (2) Department of Chemistry, Warsaw University, Poland (3) INFN-Laboratori Nazionali di Frascati, Italy (4) Institute of Solid State Physics, University of Latvia, LV-1063, Riga, Latvia; (5) Institute Laue-Langevin, F-38042 Grenoble, France;

Resume : The renewed interest in silicon carbide is connected with the synthesis of various one-dimensional nanostructures, which can be interesting in different applications. Stable 1D silicon carbide nanostructures have been obtained via combustion synthesis route. FTIR spectroscopy analysis has been done Daphne Light synchrotron facility of LNF INFN, Frascati. Infrared reflectivity spectra for unpurified and purified nano-SiC were compared with the spectra of commercially available SiC nanomaterials (experiments were carried out at 20 K and at room temperature). The performed measurements have proved that FTIR technique is very sensitive for silicon carbide nanomaterials. The manifestation of the fundamental Si and C sublattice was observed in the range of 770 to 1000 cm-1. In case of the synthesized 1D structures (nanowires) a different profile of the reflectivity peak was observed. This peak is strongly dependent on the purity of the investigated nanomaterial. For the raw synthesis product the main peak is strongly damped by background absorption. Generally, SiC nanowires show sharper reflectivity maximum than those of the nanoparticles. Small shift of the exact position of the main IR peak was also detected for 1D SiC, indicating the nanometric confinement effect.

G.G.PII..37
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Recent advances in transition metal nitrides-III : Jochen SCHNEIDER, Vladimir UGLOV
08:30
Authors : Christoph LEYENS
Affiliations : Technische Universität Dresden, Institute of Materials Science, Chair of Materials Engineering, Helmholtzstraße 7, 01062 Dresden, Germany

Resume : In aero engines, coatings are facing severe attack under multiple loading conditions. Sand erosion, e.g., can cause great damage to turbine hardware in the compressor, while hot corrosion and oxidation are of concern in the hotter parts of the engines. Today, coatings are widely applied to protect high pressure turbine airfoils, however, their use in the compressor and the low pressure turbine is scarce yet. The paper will review recent developments in the field of erosion protection of aerospace alloys such as titanium and nickel alloys indicating that Cr2AlC nanolaminate MAX phase coatings can substantially improve the component lifetimes under erosion attack. It has been shown that the Cr2AlC MAX phase exhibits good erosion protection due to its combination of metallic and ceramic properties. Furthermore, Cr2AlC has excellent oxidation resistance, particularly if doped with Y. Recently, for this MAX phase autonomous self-healing behaviour was demonstrated which fostered significant research efforts in this area. The current aim of ongoing research is to assess the potential of Cr2AlC MAX phase coatings as erosion resistant autonomous self-healing material by understanding the basic physical and chemical principles governing multiple crack closure to heal erosion damage.

G.G.IX..1
09:30
Authors : L. Major- 1, J.M. Lackner- 2, M. Kot- 3, M. Janusz- 1, J. Morgiel- 1
Affiliations : 1- Institute of Metallurgy and Materials Science, Polish Academy of Sciences, PL30-059 Cracow, 25 Reymonta Street, Cracow, Poland; 2- JOANNEUM RESEARCH- Materials- Institute for Surface Technologies and Photonics, Leobner Strasse 94, 8712 Niklasdorf, Austria; 3- AGH University of Science and Technology, Faculty of Mechanical Engineering and Robotics, Laboratory of Surface Engineering and Tribology, Al. Mickiewicza 30, PL-30059 Cracow, Poland

Resume : Nanotechnology is the ability to manipulate atoms and molecules to produce nano- structured materials and functional nano- coatings on biomedical devices and surgical tools. The use of carbon fiber composites (CFC) for surgical applications is widespread due to the exceptional physical properties of this material. Carbon fiber structures provide strength, stiffness, and fatigue resistance. Carbon fiber components are also radiolucent and clinical-chemical resistant. Carbon-based materials show, however, significant oxidative degradation in air beginning at temperatures in the region of 400 degree C. The reinforcement of carbon with carbon fibers, complicates the anti- oxidative coating problem, due to the thermal and elastic anisotropy of the carbon fibers. Therefore, a coating concept for carbon–carbon composites should consist of an inner part, which serves as structural link with stress compensation ability to the carbon substrate, and an outer part, which acts as a diffusion barrier. In the presented paper, as the inner part chromium/ chromim nitride (Cr/CrN) multilayer structure has been selected. The literature data indicates the particular meaning of Cr and CrN multilayer coatings. They are characterized by an appropriate crystallographic adjustment of subsequent constituent layers of Cr and CrN and by the creation of a transition layer between them with a thickness of several dozen of nanometers. This ensures a good connection between particular constituent layers and as a result also good maintenance properties: high adhesion, wear and corrosive resistance. The CrN and Cr lattice parameters, 4.14Å and 2.88Å, respectively, allow a cube-on-cube, close to epitaxial growth with a low mismatch (1.6%). With this idea, Cr/CrN multilayers have been designed and deposited on CFC substrates. The outer part of the coating, in the presented paper, was hydrogenated amorphous carbon (a-C:H). It is well-known that a-C:H coatings have low- friction coefficients and low-specific wear rates. Thus, the amorphous carbon coatings are very promising tribo-materials. However, the poor adhesion strength to substrate, high residual stress and weak thermal stability would limit their application. Currently, many metallic elements (Ti, W, Ag, Cr etc.) have been utilized to modify their structure, and it has been proved that the metal doping is an effective method to reduce residual stress and enhance adhesion strength of the film. Among those doping metals, Cr as one of carbide formed elements possesses an attractive combination of properties (corrosion resistance, wear resistance, etc.). Thus, in the presented paper a-C:H part of the coating was implanted by Cr nanocrystals. Coatings were subjected to complex investigations. Influence of deposition conditions on bio- tribological properties were studied. Mechanisms of a mechanical wear of analyzed systems were presented focusing on the cracking propagation revealed in ball- on- disc and scratch tests. Cell-material interaction was analyzed in the direct cell deposition. Complex microstructure analysis of presented, nano- multilayer coatings, before and after mechanical and biological tests, were performed by means of transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). The bio- tribological investigation in connection with detailed microstructure interpretation were used as a screening tool before coatings could be deposited on medical tools.

G.G.IX..4
11:00
Authors : C. Nouvellon1, N. Britun?, M. Michiels1, R. Snyders1,2
Affiliations : 1 Materia Nova Research Center - Parc Initialis, 1, Avenue Copernic, B-7000 Mons, Belgium 2Chimie des Interactions Plasma-Surface, CIRMAP, Universit? de MONS - 20, Place du Parc, B-7000 Mons, Belgium

Resume : CNx are extensively studied for tribological applications because of their high hardness and low friction coefficients. Considering the need to increase the nitrogen content in the today grown CNx films, increasing the dissociation of the nitrogen molecules in the plasma could be a promising strategy. Compared to other magnetron techniques, HiPIMS (High Power Impulse Magnetron Sputtering) enables a high ionization of the sputtered material and a strong dissociation of reactive molecules. Films have been synthesized using reactive HiPIMS of a graphite target in Ar-N2 and Ne-N2. Ne has been used because of its high ionization energy in order to increase the electronic temperature, and in turn the ionization rate. The results are compared to those obtained with a conventional DC reactive magnetron discharge at identical mean power (PD). We discuss the influence of the gas mixture on the peak current and therefore on the film chemistry, determined by XPS. Optical emission spectroscopy was performed in order to address the evolution of the plasma chemistry and temperature with respect to the gas mixture. In HiPIMS, the deposition rate increases with N2 content in Ne-N2 and is lower than in Ar-N2. In DC, the behaviour, with an opposite trend for the two gas mixtures, can be explained by the variation of the sputtering yield for the different gases. The chemical composition of the film reaches a saturation value in all cases.

G.G.X..2
11:30
Authors : Brigitte Bouchet-Fabre1, Marie-Christine Hugon 2, Mathieu Pinault 1, Eddy Foy 3, Martine Mayne-L’Hermite 1; Cécile Reynaud 1; Tibériu Minéa 2
Affiliations : 1 IRAMIS/NIMBE/LEDNA, CEA-Saclay, F- 91191 Gif / Yvette Cedex 2 LPGP, U-Psud-CNRS, Université Paris-Sud, F-91401 Orsay Cedex 3 IRAMIS/SIS2M/LAPA CEA-Saclay, F- 91191 Gif / Yvette Cedex

Resume : The comprehensive study focuses on the interplay interfaces Ta-Nx, x= [0,1.8] coating/ CNT during the growth by assisted catalyst CVD at 850°C, while using ferrocene as catalyst source. We show that the use of Ta-Nx buffer films grown by High Power Pulsed Magnetron Sputtering HIPPIMS is of special interest because it allows a larger incorporation of nitrogen inside the films and generates specific nanostructures. The CCVD process promotes reactions among C, N, O on one side, Ta, Fe on the other side. The abundant evidences collected in our experiments confirm the strong influence of these chemical reactions occurring during the CVD process, thus justifying a close scrutiny of the chemical and structural changes due to the temperature and the CCVD process. Therefore, we present here the interfaces modifications studied by grazing incidence X-ray scattering GIWAXS, high resolved electron scanning microscopy SEM-Feg and XPS. The together techniques are very helpful for exanimating the temperature effect on the morphology of the interface, giving a good picture of the nanocrystalline evolution of the buffers involved in the CNTs growth process. The CNT morphology and nanostructure is followed by TEM and Raman spectroscopy. We conclude on the huge impact of the nanostructure an surface morphology of tantalum nitride on the CNT morphology and growth, and then its influence on potential applications.

G.G.X..4
14:30
Authors : B. Krause, M. Kaufholz, S. Kotapati, T. Baumbach
Affiliations : (1) IPS, Karlsruhe Institute of Technology (KIT) (2) ANKA Synchrotron Radiation Facility, Karlsruhe Institute of Technology (KIT)

Resume : Off-normal deposition offers very interesting possibilities to tailor the nanostructure of sputter deposited thin films. Under certain deposition conditions, transition metal carbides and nitrides exhibit columnar growth. The orientation, size, and porosity of these columnar structures depend on the deposition angle. The direction of the incoming flux influences also the texture formation and can lead to tilted or biaxial textures. Both the texture and the shape of the columns allow for the control of the mechanical properties of the coating. However, for the prediction of these properties a detailed understanding of the growth process is required. Here we present an in situ X-ray study during reactive magnetron sputtering of VN under various deposition angles. The structure formation of thin films with thicknesses up to 200 nm was followed with sub-nm resolution using in situ X-ray reflectivity (XRR) and X-ray diffraction (XRD) measurements performed at the synchrotron radiation source ANKA (Karlsruhe). The XRR measurements give access to the time-dependent thickness and roughness increase of the coating, while the XRD measurements show the development of the (111) texture. The results were compared with SIMTRA simulations. The in situ study was complemented by ex situ measurements including nanoindentation, atomic force microscopy and pole figure measurements.

G.G.XI..3
15:00
Authors : D. Savchenko(1), V. Kulikovsky(1),(2), V. Vorlíček(1), J. Lančok(1), E. Kalabukhova(3)
Affiliations : (1) Institute of Physics, AS CR, Praha, Czech Republic (2) Institute for Problems of Materials Science, NASU, Kiev, Ukraine (3) V.E. Lashkaryov Institute of Semiconductor Physics, NASU, Kiev, Ukraine

Resume : Amorphous silicon carbonitride (a-SiCxNy) thin films deposited on the SiO2 substrates by reactive magnetron sputtering from SiC target without and with different nitrogen (N) incorporation have been studied by Raman and electron paramagnetic resonance (EPR) spectroscopy. Raman analysis indicates the presence of C-N, Si-N, C-C bonds in a-SiCxNy films. Three EPR signals were revealed in a-SiCxNy/SiO2. One of them with isotropic g factor at g=2.0033 and Lorentzian lineshape was attributed to the carbon-dangling bonds (CDB) located within a-SiCxNy film. Based on the lineshape and linewidth (~ 1.2 mT) the EPR signal was attributed to the unpaired electron delocalized over the sp2 carbon cluster. With increase of the N content the spin density of the CDB significantly increases. From the temperature dependence of the linewidth and integral intensity of the CDB EPR signal which obey Curie-Weiss law it was concluded that antiferromagnetic ordering occurs in the spin system. The value of the antiferromagnetic exchange constant between dangling bonds was found to be J=–32 K. The second EPR signal having g=2.009 was attributed to the interface defect representing threefold-coordinated Si dangling bond which may appear due to the formation of the oxidized silicon on the top surface of the film. The third EPR signal with g=2.05 was tentatively attributed to the trapped holes at Si atom. The work was supported by GA ČR 13-06697P and SAFMAT project CZ.2.16/3.1.00/22132.

G.G.XI..5
15:15
Authors : C. Pardanaud1, C. Martin1, G. Giacometti1, P. Roubin1, B. Pégourié2, C. Hopf3, T. Schwarz-Selinger3, W. Jacob3
Affiliations : 1 Aix-Marseille Université-CNRS, PIIM, 13397 Marseille cedex 20, France; 2 CEA, IRFM, 13108 Saint-Paul-lez-Durance, France; 3 Max-Planck-Institute für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching, Germany

Resume : Hydrogen isotopes plasma/walls interactions in carbon tokamaks lead to a severe safety issue avoiding carbon use in the future ITER project. A complete analysis of the D retention in the Tore Supra tokamak, including both in-situ gas balance measurements and ex-situ post-mortem characterizations, has revealed that deuterium was depleted in the deep layers of the deposits, indicating that an unexpected long term D-release occurs. To mimic the variety of hydrogenated deposits found in Tore Supra, we used several reference samples and heated them to relevant temperatures (120-1000°C). These samples had various C(sp2)/C(sp3)/H content and were PECVD layers with properties ranging from soft to hard films (DC bias from -100 to -300 V corresponding respectively to H/(H+C) equal to 37 and 29 at.%). We have studied the thermal stability of these samples using in-situ Raman microspectroscopy under argon atmosphere, recording their evolution during hours or days. Ultra High Vacuum thermal desorption spectroscopy and ion beam analysis were done separately for comparison. We have identified selected Raman parameters as C(sp3)-H and/or C(sp2)-H sensitive. For example, for the -300 V DC bias sample, carbon reorganization with aromatization and loss of C(sp3) occurs in the first 100 minutes at 500 °C. A similar reorganization is detected in the temperature range of 450 - 600°C. H release occurs on a longer timescale of about 10 hours at 500 °C and H release from C(sp2) is only partial, even after several days. These processes occur more rapidly with higher initial H content. Similar analyses have been done for deposits produced in the Tore Supra tokamak to get insights into their structure and on the long term D release processes.

G.G.XI..6
 
Energy related applications : Gregory ABADIAS, Thien-Phap NGUYEN
16:30
Authors : J.F. Pierson1, S. Bouhtiyya1, R. Lucio Porto2, F. Capon1, T. Brousse2
Affiliations : 1 Institut Jean Lamour, Université de Lorraine, Nancy, France 2 Institut des Matériaux Jean Rouxel, Université de Nantes, Nantes, France

Resume : The high hardness and the low friction coefficient of transition metal nitride (TMN) films allow their use as protective coatings. These materials exhibit also functional properties that make TMN films suitable for applications in energy storage devices. This talk aims to screen the potential use of nitride thin films in supercapacitors. TMN films were deposited on glass substrates by reactive magnetron sputtering of TM targets (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Nb and Ru). Only Cu- and Ni-based films crystallized in a TM3N-like structure while most of the deposited films exhibit a metal to nitrogen atomic ratio of 1. Only limited information about the structure of MnN and RuN is available in the literature. Subsequently, the structure of these two nitrides is described for the first time. X-ray diffraction analyses and the Rietveld’s method evidence that both RuN and MnN thin films crystallize in a ZnS-like structure with lattice constant of 0.451 and 0.428 nm, respectively. The electrochemical properties of the deposited films were determined by cyclic voltammetry in electrolytes KOH. ScN, Ni3N, FeN, CrN have shown a poor capacitance suggesting that only double layer is involved in the charge storage mechanism. The large capacitance of MnN, RuN and VN and the nearly rectangular shape of the voltammograms suggest a pseudofaradaic process. These electrochemical results are discussed in connection with the film structure and composition.

G.G.XII..1
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Graphenes - I : Bodgana MITU, Pierre-Yves TESSIER
08:30
Authors : C. Mathioudakis, P. C. Kelires
Affiliations : Research Unit for Nanostructured Materials Systems, Department of Mechanical and Materials Science Engineering, Cyprus University of Technology, P.O. Box 50329, 3603 Lemesos, Cyprus

Resume : In the low-density regime of carbon materials, nanoporous formation along with nanostructuring and coexistence of various hybridizations give rise to three-dimensional (3D) structures with outstanding properties. Carbon nanofoams (CNFs) belong to this class of materials. They are open, random and light structures resembling a foam. We have recently studied [1] CNFs made up of schwarzites, nanostructures with negative Gaussian curvature. Here, we investigate two other forms of this exciting material. One is made of carbon nanotubes (CNT) and the other of graphene nanoflakes (GNF). These 3D randomly interconnected structures offer an alternative route for promising applications. Our studies are based on Monte Carlo simulations for the network formation, followed by tight-binding molecular dynamics simulations for full relaxation and calculation of the mechanical and optoelectronic properties. We find that both foam types are rigid, despite their porous nature, so they can be utilized in applications (catalysis, tribology, energy storage) as thin films. The GNF foams exhibit high conductivity, approaching that of single-layer graphene, and high optical absorptivity. Similar properties are exhibited by the CNT foams. This makes these 3D manifestations invaluable for applications in electronics and optics. [1] C. Mathioudakis and P. C. Kelires, Phys. Rev. B 87, 195408 (2013).

G.G.XIII..1
08:45
Authors : Ehsan Rezvani1, Niall McEvoy2, Hugo Nolan1,2, Clive Downing, Toby Hallam and Georg Duesberg1
Affiliations : 1) School of Chemistry, Trinity College Dublin, Dublin 2, Ireland, 2) CRANN, Trinity College Dublin, Dublin 2, Ireland.

Resume : Graphene, an atomically thin sheet of sp2-hybridised carbon atoms arranged in a honeycomb lattice, has attracted a great deal of interest among the scientific community primarily because of its extraordinary electronic properties. The introduction of dopants has been proposed for applications in nanoelectronics and sensing. In particular, nitrogen dopants can act as electron donors in nitrogen-doped (N-doped) graphitic systems. N-doping of graphene is advantageous for high frequency semiconductor device applications and this material is considered an excellent candidate for energy storage and solar cell applications. Most recently, N-doped graphene has been reported to act as a catalyst in oxygen reduction reactions (ORR) which are crucial in energy conversion. For chemical functionalisation there are several sub-categories, namely surface doping and substitutional doping which can both give rise to either p-type or n-type electronic behaviour. Substitutional nitrogen doping of graphene has been reported by means of different techniques such as chemical vapour deposition, annealing under ammonia atmosphere, arc-discharge of graphite under pyridine/ammonia ambient, wet chemical routes and nitrogen plasma treatment. In spite of its crucial importance, details on the mechanism of incorporation of heteroatoms into graphene remain unclear. We have developed a downstream plasma doping technique using a custom-built apparatus in which the samples are placed at a location remote from the plasma source, thereby minimising the destructive effect of plasma species. Using this approach, an initial oxygen plasma treatment is performed on the pristine sample creating active sites for accommodating further functional groups. A subsequent plasma treatment is then carried out with a mixture of hydrogen and ammonia which simultaneously reduces and N-dopes the graphene. Elsewhere, a similar approach has been shown to simultaneously reduce and N-dope graphene oxide powder. Here we report on the TEM and energy-filtered TEM characterisation of plasma functionalised CVD graphene. Comparative TEM/EELS studies were performed on three different CVD-grown graphene sample types. Namely pristine graphene, O2 plasma treated graphene and O2 followed by H2+NH3 plasma treated graphene. The results show the evolution of pristine untreated graphene to a disordered oxygenated graphene upon O2 plasma treatment and subsequent partial restoration of crystallinity of the graphene lattice following H2+NH3 plasma. This study further probes our N-doped graphene using several spectroscopic techniques, thus offering further information on the nature of doping in graphene. In conclusion, we report on the application of EELS in conjunction with two other spectroscopic techniques for full characterisation of remote plasma-treated CVD-grown graphene. This allowed for a highly detailed analysis of nitrogen-doped graphene; elucidating the structural evolution, along with the nature and bonding states of dopants present. TEM and EELS studies show distortion of the graphene lattice upon oxygen-plasma treatment which is further confirmed by Raman spectroscopy via the emergence of defect related peaks; as well as XPS, with an increased contribution from sp3 carbon bonds and oxygen functional groups. A subsequent H2+NH3 plasma treatment results in partial lattice restoration which is evident from the electron diffraction pattern; this is further corroborated by the better defined peaks and additional features and shoulders in the EEL spectrum. Again, these results are supported via Raman spectroscopy with the re-emergence of long range order and suppression of defect-related peaks. XPS indicates the restoration of the lattice to a graphitic structure with the removal of oxygen groups and the introduction of nitrogen as a dopant. The nature of the nitrogen functional groups was also established. These results show that EELS can be applied to chemically and crystallographically monitor the chemical changes in graphene and its derivatives and, hence, shed light on an established technique as a new avenue for better understanding of the structural variations of graphene upon chemical treatments. Furthermore, the restoration of the graphene crystalline lattice in conjunction with the introduction of nitrogen dopants following the two-step plasma treatment suggests that this plasma treatment technique is a viable method of producing nitrogen-doped CVD graphene for incorporation into further device applications.

G.G.XIII..2
09:00
Authors : S. Kaciulis, A . Mezzi, S.K. Balijepalli, M. Lavorgna, H. Xia
Affiliations : Institute for the Study of Nanostructured Materials, ISMN – CNR, Roma, Italy; Institute of Composite and Biomedical Materials, IMCB – CNR, Napoli, Italy; State Key Laboratory of Polymer Materials Engineering, Sichuan University, China

Resume : Composite materials with 2D carbon (graphene and/or single wall carbon nanotubes) are very promising due to their extraordinary electrical and mechanical properties. Graphene and natural rubber composites, which may be used for gaskets or sealants, were prepared by ultrasonically assisted latex mixing exfoliation and in-situ reduction process, varying the distribution of the filler in the samples. They present a low electrical conductivity and barrier properties, in spite of excellent spatial distribution. On the other hand, natural rubber composites, prepared by latex mixing and co-coagulation, exhibit a segregated 3D graphene network where the graphene sheets are stacked within the interstices of the coagulated latex particles. These vulcanized composites exhibit good electrical conductivity and high mechanical strength together with excellent barrier properties. The standards for the compositional characterization of these materials still are not established. In addition to the mostly used techniques, such as Raman spectroscopy and electron microscopy, also Auger electron spectroscopy (AES) can be employed for the identification of graphene. In this study, the shape of C KVV peak, excited by electron beam (AES) and X-ray photons (XAES), has been investigated in different composite materials containing graphene and SWCNTs. A new method for 2D carbon recognition, based on the D parameter, determined from C KVV spectra excited by X-ray photons, was proposed and verified.

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