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  • 251.
    Zhu, Jianqiang
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Johansson Jöesaar, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology. Seco Tools, Fagersta, Sweden.
    Polcik, Peter
    PLANSEE Composite Materials GmbH.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Greczynski, Grzegorz
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Influence of Ti-Si cathode grain size on the cathodic arc process and resulting Ti-Si-N coatings2013In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 235, no 25, p. 637-647Article in journal (Refereed)
    Abstract [en]

    The influence of the Ti-Si cathode grain size on cathodic arc processes and resulting Ti-Si-N coating synthesis has been studied. 63 mm Ti-Si cathodes containing 20-25 at % Si with four dedicated grain size of ~8 µm, ~20 µm, ~110 µm, and ~600 µm were fabricated via spark plasma sintering or hot isostatic pressing. They were evaporated in 2 Pa nitrogen atmosphere in an industrial-scale arc deposition system and the Ti-Si-N coatings were grown at 50 A, 70 A, and 90 A arc current. The composition and microstructure of the virgin and worn cathode surfaces as well as the resulting coatings were characterized using optical and electron microscopy, x-ray diffraction, elastic recoil detection analysis, x-ray photoelectron spectroscopy, and nanoindentation. The results show that the existence of multiple phases with different work function values directly influences the cathode spot ignition behavior and also the arc movement and appearance. Specifically, there is a preferential erosion of the Ti5Si3-phase grains. By increasing the grain size of the virgin cathode, the preferential erosion is enhanced, such that the cathode surface morphology roughens substantially after 600 Ah arc discharging. The deposition rate of the Ti-Si-N coating is increased with decreasing grain size of the evaporated Ti-Si cathodes. The composition, droplet density, and droplet shape of the coatings are influenced by the arc movement, which is also shown to depend on the cathode grain size.

  • 252.
    Olsson, Simon
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Garbrecht, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Eriksson, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Ion-assisted Growth of Quasicrystalline Cu-Al-Sc Directly from the Vapor Phase2013Manuscript (preprint) (Other academic)
    Abstract [en]

    Ion assisted depositions have been used to grow the Al38Cu46Sc16 quasicrystalline phase directly from the vapor phase in thin film form. Diffraction experiments reveal that amorphous films are formed at room temperature. The quasicrystalline phase formed at a substrate temperature of 340 °C with an improved quality at higher temperatures up to 460 °C. The quasicrystal film quality is improved by increasing the ion flux during ion-assisted growth with ion energies of 26.7 eV. Increasing the ion energy further was however found to cause resputtering and defects in the film. Electron microscopy reveals a polycrystalline microstructure with crystal grains in the shape of thin needles.

  • 253.
    Kodambaka, S
    et al.
    University of Calif Los Angeles, CA USA.
    Ngo, C
    University of Calif Los Angeles, CA USA.
    Palisaitis, Justinas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Mayrhofer, P H.
    Vienna University of Technology, Austria.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Persson, Per O A
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Kinetics of Ga droplet decay on thin carbon films2013In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 102, no 16Article in journal (Refereed)
    Abstract [en]

    Using in situ transmission electron microscopy, we investigated the kinetics of liquid Ga droplet decay on thin amorphous carbon films during annealing at 773 K. The transmission electron microscopy images reveal that liquid Ga forms spherical droplets and undergo coarsening/decay with increasing time. We find that the droplet volumes change non-linearly with time and the volume decay rates depend on their local environment. By comparing the late-stage decay behavior of the droplets with the classical mean-field theory model for Ostwald ripening, we determine that the decay of Ga droplets occurs in the surface diffusion limited regime.

  • 254.
    Monemar, Bo
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Khromov, Sergey
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Pozina, Galia
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Paskov, Plamen
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hemmingsson, Carl
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Amano, Hiroshi
    Nagoya University, Japan.
    Avrutin, Vitaliy
    Virginia Commonwealth University, VA USA.
    Li, Xing
    Virginia Commonwealth University, VA USA.
    Morkoc, Hadis
    Virginia Commonwealth University, VA USA.
    Luminescence of Acceptors in Mg-Doped GaN2013In: Japanese Journal of Applied Physics, ISSN 0021-4922, E-ISSN 1347-4065, Vol. 52, no 8Article in journal (Refereed)
    Abstract [en]

    Recent photoluminescence (PL) data for Mg-doped GaN at 2 K are discussed, with reference to published theoretical calculations of the electronic level structure. It is concluded that the typical PL peaks at 3.466 eV (acceptor bound exciton ABE1) and the broader 3.27 eV donor-acceptor pair (DAP) PL are the expected standard PL signatures of the substitutional Mg acceptor. Additional broader peaks at 3.455 eV (ABE2) and 3.1 eV are suggested to be related to the same acceptors perturbed by nearby basal plane stacking faults. The low temperature metastability of PL spectra is assigned to a nonradiative metastable deep level.

  • 255.
    Pettersson, M
    et al.
    Uppsala University, Sweden.
    Tkachenko, S
    Uppsala University, Sweden.
    Schmidt, Susann
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Berlind, Torun
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Jacobson, S
    Uppsala University, Sweden.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Engqvist, H
    Uppsala University, Sweden.
    Persson, C
    Uppsala University, Sweden.
    Mechanical and tribological behavior of silicon nitride and silicon carbon nitride coatings for total joint replacements2013In: Journal of The Mechanical Behavior of Biomedical Materials, ISSN 1751-6161, E-ISSN 1878-0180, Vol. 25, p. 41-47Article in journal (Refereed)
    Abstract [en]

    Total joint replacements currently have relatively high success rates at 10–15 years; however, increasing ageing and an active population places higher demands on the longevity of the implants. A wear resistant configuration with wear particles that resorb in vivo can potentially increase the lifetime of an implant. In this study, silicon nitride (SixNy) and silicon carbon nitride (SixCyNz) coatings were produced for this purpose using reactive high power impulse magnetron sputtering (HiPIMS). The coatings are intended for hard bearing surfaces on implants. Hardness and elastic modulus of the coatings were evaluated by nanoindentation, cohesive, and adhesive properties were assessed by micro-scratching and the tribological performance was investigated in a ball-on-disc setup run in a serum solution. The majority of the SixNy coatings showed a hardness close to that of sintered silicon nitride (∼18 GPa), and an elastic modulus close to that of cobalt chromium (∼200 GPa). Furthermore, all except one of the SixNy coatings offered a wear resistance similar to that of bulk silicon nitride and significantly higher than that of cobalt chromium. In contrast, the SixCyNz coatings did not show as high level of wear resistance.

  • 256.
    Knutsson, Axel
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Ullbrand, Jennifer
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Rogström, Lina
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Norrby, Niklas
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Johnson, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Almer, J.
    Advanced Photon Source, Argonne National Laboratory, Argonne, USA.
    Johansson, M.P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology. Seco Tools AB, Fagersta, Sweden.
    Jansson, B.
    Seco Tools AB, Fagersta, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Microstructure evolution during the isostructural decomposition of TiAlN: a combined in-situ small angle x-ray scattering and phase field study2013In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 113, no 21Article in journal (Refereed)
    Abstract [en]

    This paper describes details of the spinodal decomposition and coarsening in metastable cubic Ti0.33Al0.67N and Ti0.50Al0.50N coatings during isothermal annealing, studied by in-situ small angle x-ray scattering, in combination with phase field simulations. We show that the isostructural decomposition occurs in two stages. During the initial stage, spinodal decomposition, of the Ti0.50Al0.50N alloy, the phase separation proceeds with a constant compositional wavelength of ∼2.8 nm of the AlN- and TiN-rich domains. The time for spinodal decomposition depends on annealing temperature as well as alloy composition. After the spinodal decomposition, the coherent cubic AlN- and TiN-rich domains coarsen. The coarsening rate is kinetically limited by diffusion, which allowed us to estimate the diffusivity and activation energy of the metals to 1.4 × 10−6 m2 s−1 and 3.14 eV at−1, respectively.

  • 257.
    Ghafoor, Naureen
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Johnson, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Klenov, Dmitri
    FEI Company, Eindhoven, The Netherlands.
    Demeulemeester, Jelly
    École Polytechnique de Montréal, Canada.
    Desjardins, Patrick
    École Polytechnique de Montréal, Canada.
    Petrov, Ivan
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology. University of Illinois, Urbana, USA.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Nanolabyrinthine ZrAlN thin films by self-organization of interwoven single-crystal cubic and hexagonal phases2013In: APL Materials, ISSN 2166-532X, Vol. 1, no 2, p. 022105-1-022105-6Article in journal (Refereed)
    Abstract [en]

    Self-organization on the nanometer scale is a trend in materials research. Thermodynamic driving forces may, for example, yield chessboard patterns in metal alloys[Y. Ni and A. G. Khachaturyan, Nature Mater. 8, 410–414 (2009)] or nitrides [P. H.Mayrhofer, A. Horling, L. Karlsson, J. Sj ¨ ol¨ en, T. Larsson, and C. Mitterer, Appl. ´Phys. Lett. 83, 2049 (2003)] during spinodal decomposition. Here, we explore theZrN-AlN system, which has one of the largest positive enthalpies of mixing amongthe transition metal aluminum nitrides [D. Holec, R. Rachbauer, L. Chen, L. Wang,D. Luefa, and P. H. Mayrhofer, Surf. Coat. Technol. 206, 1698–1704 (2011); B.Alling, A. Karimi, and I. Abrikosov, Surf. Coat. Technol. 203, 883–886 (2008)].Surprisingly, a highly regular superhard (36 GPa) two-dimensional nanolabyrinthinestructure of two intergrown single crystal phases evolves during magnetron sputter thin film synthesis of Zr0.64Al0.36N/MgO(001). The self-organization is surfacedriven and the synergistic result of kinetic limitations, where the enthalpy reductionbalances both investments in interfacial and elastic energies.

  • 258.
    Broitman, Esteban
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Yousuf Soomro, Muhammad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Nanoscale piezoelectric response of ZnO nanowires measured using a nanoindentation technique2013In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 15, no 26, p. 11113-11118Article in journal (Refereed)
    Abstract [en]

    We report the piezoelectric properties of ZnO nanowires (NWs) obtained by using a nanoindenter with a conductive boron-doped diamond tip. The direct piezoelectric effect was measured by performing nanoindentations under load control, and the generated piezoelectric voltage was characterized as a function of the applied loads in the range 0.2-6 mN. The converse piezoelectric effect was measured by applying a DC voltage to the sample while there was a low applied force to allow the tip being always in physical contact with the NWs. Vertically aligned ZnO NWs were grown on inexpensive, flexible, and disposable paper substrates using a template-free low temperature aqueous chemical growth method. When using the nanoindenter to measure the direct piezoelectric effect, piezopotential values of up to 26 mV were generated. Corresponding measurement of the converse piezoelectric effect gave an effective piezoelectric coefficient d(33)(eff) of similar to 9.2 pm V-1. The ZnO NWs were also characterized using scanning electron microscopy, X-ray diffraction, and high-resolution transmission electron microscopy. The new nanoindentation approach provides a straightforward method to characterize piezoelectric material deposited on flexible and disposable substrates for the next generation of nanodevices.

  • 259.
    Naguib, Michael
    et al.
    Drexel University, PA USA .
    Halim, Joseph
    Drexel University, PA USA .
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Cook, Kevin M:
    Drexel University, PA USA .
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Gogotsi, Yury
    Drexel University, PA USA .
    Barsoum, Michel E.
    Drexel University, PA USA .
    New Two-Dimensional Niobium and Vanadium Carbides as Promising Materials for Li-Ion Batteries2013In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 135, no 43, p. 15966-15969Article in journal (Refereed)
    Abstract [en]

    New two-dimensional niobium and vanadium carbides have been synthesized by selective etching, at room temperature, of Al from Nb2AlC and V2AlC, respectively. These new matrials are promising electrode materials for Li-ion batteries, demonstrating good capability to handle high charge-discharge rates. Reversible capacities of 170 and 260 mA.h.g(-1) at 1 C, and 110 and 125 mA.h.g(-1) at 10 C were obtained for Nb2C and V2C-based electrodes, respectively.

  • 260.
    Pearce, Ruth
    et al.
    National Physical Laboratory, Teddington, UK.
    Eriksson, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, The Institute of Technology.
    Iakimov, Tihomir
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, The Institute of Technology.
    Yakimova, Rositza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    On the Differing Sensitivity to Chemical Gating of Single and Double Layer Epitaxial Graphene Explored Using Scanning Kelvin Probe Microscopy2013In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 7, no 5, p. 4647-4656Article in journal (Refereed)
    Abstract [en]

    Using environmental scanning Kelvin probe microscopy we show that the position of the Fermi level of single layer graphene is more sensitive to chemical gating than that of double layer graphene. We calculate that the difference in sensitivity to chemical gating is not entirely due to the difference in band structure of 1 and 2 layer graphene. The findings are important for gas sensing where the sensitivity of the electronic properties to gas adsorption are monitored and suggest that single layer graphene could make a more sensitive gas sensor than double layer graphene. We propose that the difference in surface potential between adsorbate-free single and double layer graphene, measured using scanning kelvin probe microscopy, can be used as a non-invasive method of estimating substrate-induced doping in epitaxial graphene.

  • 261.
    Mockuté, Aurelija
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Dahlqvist, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    O A Persson, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Oxygen incorporation in Ti2AlC thin films studied by electron energy loss spectroscopy and ab initio calculations2013In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 48, no 10, p. 3686-3691Article in journal (Refereed)
    Abstract [en]

    Substitution of C with O in hexagonal inherently nanolaminated Ti2AlC has been studied experimentally and theoretically. Ti2Al(C1−x O x ) thin films with x ≤ 0.52 are synthesized by both cathodic arc deposition with the uptake of residual gas O, and solid-state reaction between understoichiometric TiC y and Al2O3(0001) substrates. The compositional analysis is made by analytical transmission electron microscopy, including electron energy loss spectroscopy. Furthermore, predictive ab initio calculations are performed to evaluate the influence of substitutional O on the shear stress at different strains for slip on the (0001) basal plane in the [−1010] and [1−210] directions.

  • 262.
    Olsson, Simon
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Garbrecht, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Eriksson, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Phase Evolution of Multilayered Al/Cu/Co Thin Films into Decagonal Al-Cu-Co and Al-Cu-Co-Si Quasicrystalline Phases2013Manuscript (preprint) (Other academic)
    Abstract [en]

    Multilayered Al/Cu/Co thin films have been prepared by magnetron sputtering on Al2O3(0001) and Si(001) substrates and the phase evolution has been investigated. The decagonal d-Al-Cu-Co and d-Al-Cu-Co-Si phases were found to form at 500 °C, and at 600 °C these were the only phases. At increasing temperatures, the quasicrystals grew larger in size, up to 500 nm, although always smaller for the d-Al-Cu-Co-Si, and obtained a texturing with the 10-fold periodic axis aligned with the substrate normal. The d-Al-Cu-Co phase persisted to more than 850 °C, with a complete texturing, while the d-Al-Cu-Co-Si phase was replaced by other crystalline phases at 800 °C.

  • 263.
    Frodelius, Jenny
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Paul, Dennis
    Phys Elect USA, USA .
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Phase stability and initial low-temperature oxidation mechanism of Ti2AlC thin films2013In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 33, no 2, p. 375-382Article in journal (Refereed)
    Abstract [en]

    Ti2AlC thin films deposited onto Al2O3 by magnetron sputtering were used as model for studying the early stages (andlt; 15 min) of relatively low-temperature (500 degrees C) oxidation of Ti2AlC. The well-defined microstructure of these films forms a surface of valleys, hillocks and plateaus comprised of basal-plane-oriented grains with a fraction of nonbasal-plane-oriented grains with out-of-plane orientation of (1 0 (1) over bar 3) and (1 0 (1) over bar 6) as shown by X-ray diffraction and s electron microscopy. During oxidation, Al2O3 clusters and areas of C-containing titania (TiOxCy) are formed on the surface. A mechanism is proposed in which the locations of the Al2O3 clusters are related to the migration of Al atoms diffusing out of Ti2AlC. The Al2O3 is initially formed in valleys or on plateaus where Al atoms have been trapped while TiOxCy forms by in-diffusion of oxygen into the Al-deficient Ti2AlC. At 500 degrees C, the migration of Al atoms is faster than the oxidation kinetics; explaining this microstructure-dependent oxidation mechanism.

  • 264.
    Petruhins, Andrejs
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Ingason, Arni Sigurdur
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Dahlqvist, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Mockuté, Aurelija
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Junaid, Muhammad
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Persson, Per O A
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Phase stability of Crn+1GaCn MAX phases from first principles and Cr2GaC thin-film synthesis using magnetron sputtering from elemental targets2013In: Physica Status Solidi. Rapid Research Letters, ISSN 1862-6254, E-ISSN 1862-6270, Vol. 7, no 11, p. 971-974Article in journal (Refereed)
    Abstract [en]

    Ab-initio calculations have been used to investigate the phase stability and magnetic state of Crn+ 1GaCn MAX phase. Cr2GaC (n = 1) was predicted to be stable, with a ground state corresponding to an antiferromagnetic spin configuration. Thin-film synthesis by magnetron sputtering from elemental targets, including liquid Ga, shows the formation of Cr2GaC, previously only attained from bulk synthesis methods. The films were deposited at 650 degrees C on MgO(111) substrates. X-ray diffraction and high-resolution transmission electron microscopy show epitaxial growth of (000) MAX phase.

  • 265.
    Mei, A B
    et al.
    University of Illinois, IL 61801 USA .
    Howe, B M
    Air Force Research Lab, OH 45433 USA .
    Zhang, C
    University of Illinois, IL 61801 USA .
    Sardela, M
    University of Illinois, IL 61801 USA .
    Eckstein, J N
    University of Illinois, IL 61801 USA .
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Rockett, A
    University of Illinois, IL 61801 USA .
    Petrov, I
    University of Illinois, IL 61801 USA .
    Greene, J E
    University of Illinois, IL 61801 USA .
    Physical properties of epitaxial ZrN/MgO(001) layers grown by reactive magnetron sputtering2013In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 31, no 6, p. 061516-Article in journal (Refereed)
    Abstract [en]

    Single-crystal ZrN films, 830 nm thick, are grown on MgO(001) at 450 degrees C by magnetically unbalanced reactive magnetron sputtering. The combination of high-resolution x-ray diffraction reciprocal lattice maps, high-resolution cross-sectional transmission electron microscopy, and selected-area electron diffraction shows that ZrN grows epitaxially on MgO(001) with a cube-on-cube orientational relationship, (001)(ZrN)parallel to(001)(MgO) and [100](ZrN)parallel to[100](MgO). The layers are essentially fully relaxed with a lattice parameter of 0.4575 nm, in good agreement with reported results for bulk ZrN crystals. X-ray reflectivity results reveal that the films are completely dense with smooth surfaces (roughness = 1.3 nm, consistent with atomic-force microscopy analyses). Based on temperature-dependent electronic transport measurements, epitaxial ZrN/MgO(001) layers have a room-temperature resistivity rho(300K) of 12.0 mu Omega-cm, a temperature coefficient of resistivity between 100 and 300K of 5.6 x 10(-8) Omega-cm K-1, a residual resistivity rho(o) below 30K of 0.78 mu Omega-cm (corresponding to a residual resistivity ratio rho(300K)/rho(15K) = 15), and the layers exhibit a superconducting transition temperature of 10.4 K. The relatively high residual resistivity ratio, combined with long in-plane and out-of-plane x-ray coherence lengths, xi(parallel to) = 18 nm and xi(perpendicular to) = 161 nm, indicates high crystalline quality with low mosaicity. The reflectance of ZrN(001), as determined by variable-angle spectroscopic ellipsometry, decreases slowly from 95% at 1 eV to 90% at 2 eV with a reflectance edge at 3.04 eV. Interband transitions dominate the dielectric response above 2 eV. The ZrN(001) nanoindentation hardness and modulus are 22.7 +/- 1.7 and 450 +/- 25 GPa.

  • 266.
    Schmidt, Susann
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Goyenola, Cecilia
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Gueorguiev, Gueorgui Kostov
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Greczynski, Grzegorz
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Gueorguiev Ivanov, Ivan
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Czigany, Zs
    Hungarian Academic Science, Hungary .
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Reactive high power impulse magnetron sputtering of CFx thin films in mixed Ar/C4F4 and Ar/C4F8 discharges2013In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 542, p. 21-30Article in journal (Refereed)
    Abstract [en]

    The reactive high power impulse magnetron sputtering processes of carbon in argon/tetrafluoromethane (CF4) and argon/octafluorocyclobutane (c-C4F8) have been characterized. Amorphous carbon fluoride (CFx) films were synthesized at deposition pressure and substrate temperature of 400 mPa and 110 degrees C, respectively. The CFx film composition was controlled in the range of 0.15 andlt; x andlt; 0.35 by varying the partial pressure of the F-containing gases from 0 mPa to 110 mPa. The reactive plasma was studied employing time averaged positive ion mass spectrometry and the resulting thin films were characterized regarding their composition, chemical bonding and microstructure as well as mechanical properties by elastic recoil detection analysis, X-ray photoelectron spectroscopy, transmission electron microscopy, nanoindentation, and water droplet contact angle measurements, respectively. The experimental results were compared to results obtained by first-principles calculations based on density functional theory. The modeling of the most abundant precursor fragment from the dissociation of CF4 and C4F8 provided their relative stability, abundance, and reactivity, thus permitting to evaluate the role of each precursor during film growth. Positive ion mass spectrometry of both fluorine plasmas shows an abundance of CF+, C+, CF2+, and CF3+ (in this order) as corroborated by first-principles calculations. Only CF3+ exceeded the Ar+ signal in a CF4 plasma. Two deposition regimes are found depending on the partial pressure of the fluorine-containing reactive gas, where films with fluorine contents below 24 at.% exhibit a graphitic nature, whereas a polymeric structure applies to films with fluorine contents exceeding 27 at.%. Moreover, abundant precursors in the plasma are correlated to the mechanical response of the different CFx thin films. The decreasing hardness with increasing fluorine content can be attributed to the abundance of CF3+ precursor species, weakening the carbon matrix.

  • 267.
    Fallqvist, Amie
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Ghafoor, Naureen
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Fager, Hanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Persson, Per O A
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Self-organization during Growth of ZrN/SiNx Multilayers by Epitaxial Lateral Overgrowth2013In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 114, no 224302Article in journal (Refereed)
    Abstract [en]

    ZrN/SiNx nanoscale multilayers were deposited on ZrN seed layers grown on top of MgO(001) substrates by dc magnetron sputtering with a constant ZrN thickness of 40 Å and with an intended SiNx thickness of 2, 4, 6, 8, and 15 Å at a substrate temperature of 800 °C and 6 Å at 500 °C. The films were investigated by X-ray diffraction, high-resolution scanning transmission electron microscopy, and energy dispersive X-ray spectroscopy. The investigations show that the SiNx is amorphous and that the ZrN layers are crystalline. Growth of epitaxial cubic SiNx – known to take place on TiN(001) – on ZrN(001) is excluded to the monolayer resolution of this study. During the course of SiNx deposition, the material segregates to form surface precipitates in discontinuous layers for SiNx thicknesses ≤ 6 Å that coalesce into continuous layers for 8 and 15 Å thickness at 800 °C, and for 6 Å at 500 °C. The SiNx precipitates are aligned vertically. The ZrN layers in turn grow by epitaxial lateral overgrowth on the discontinuous SiNx in samples deposited at 800 °C with up to 6 Å thick SiNx layers. Effectively a self-organized nanostructure can be grown consisting of strings of 1-3 nm large SiNx precipitates along apparent column boundaries in the epitaxial ZrN.

  • 268.
    Greczynski, Grzegorz
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Kindlund, Hanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Petrov, Ivan
    University of Illinois, Urbana, Illinois, USA.
    Greene, Joseph E
    University of Illinois, Urbana, Illinois.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Sputter-cleaned Epitaxial VxMo(1-x)Ny/MgO(001) Thin Films Analyzed by X-ray Photoelectron Spectroscopy: 2. Single-crystal V0.47Mo0.53N0.922013In: Surface Science Spectra, ISSN 1055-5269, E-ISSN 1520-8575, Vol. 20, p. 74-79Article in journal (Refereed)
    Abstract [en]

    Epitaxial Vx Mo (1-x)Ny thin films grown by ultrahigh vacuum reactive magnetron sputter deposition on MgO(001) substrates are analyzed by x-ray photoelectron spectroscopy (XPS). This contribution presents analytical results for 300-nm-thick single-crystal V0.47 Mo 0.53N0.92/MgO(001) films deposited by reactive cosputtering from V (99.95% purity) and Mo (99.95% purity) targets. Film growth is carried out in a UHV chamber with base pressure 2 × 10−9 Torr at 700 °C in mixed Ar/N2 atmospheres at a total pressure of 5 mTorr, with a N2 partial pressure of 3.2 mTorr; a bias of −30 V is applied to the substrate. Films composition is determined by Rutherford backscattering spectrometry (RBS). XPS measurements employ monochromatic Al K α radiation (hν = 1486.6 eV) to analyze V0.47 Mo 0.53N0.92(001) surfaces sputter-cleaned in-situ with 4 keV Ar+ ions incident at an angle of 70° with respect to the surface normal. XPS results show that the ion-etched sample surfaces have no measurable oxygen or carbon contamination; film composition, obtained using XPS sensitivity factors, is V0.34 Mo 0.66N0.81. All core level peaks, including the nearby Mo 3p3/2 (binding energy of 394.1 eV) and N 1s (at 397.5 eV) peaks, are well-resolved. Comparison to the V0.48 Mo 0.52N0.64 single-crystal film, submitted separately to Surface Science Spectra, indicates that with decreasing growth temperature from 900 to 700 °C (and increasing nitrogen concentration in Vx Mo (1-x)Ny from y = 0.64 to 0.81) the N 1s core level peak shifts towards lower binding energy by 0.1 eV while all metal atom peaks move in the opposite direction by the same amount.

  • 269.
    Greczynski, Grzegorz
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Kindlund, Hanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Petrov, Ivan
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology. Department of Materials Science and the Fredrick Seitz Materials Research Laboratory, University of Illinois, Urbana, USA.
    Greene, Joseph
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology. Department of Materials Science and the Fredrick Seitz Materials Research Laboratory, University of Illinois, Urbana, USA.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Sputter-cleaned Epitaxial VxMo(1-x)Ny/MgO(001)Thin Films Analyzed by X-ray PhotoelectronSpectroscopy: 1. Single-crystal V0.48Mo0.52N0.642013In: Surface Science Spectra, ISSN 1055-5269, E-ISSN 1520-8575, Vol. 20, no 1, p. 68-73Article in journal (Refereed)
    Abstract [en]

    Epitaxial VxMo(1-x)Ny thin films grown by ultrahigh vacuum reactive magnetron sputter deposition on Mg(001) substrates are analyzed by x-ray photoelectron spectroscopy (XPS). This contribution presents analytical results for 300-nm-thick single-crystal V0.48Mo0.52N0.64 films deposited by reactive cosputtering from V (99.95 % purity) and Mo (99.95 % purity) targets. Film growth is carried out at 900 °C in mixed Ar/N2 atmospheres at a total pressure of 5 mTorr, with a N2 partial pressure of 3.2 mTorr; a bias of −30 V is applied to the substrate. Films composition is determined by Rutherford backscattering spectrometry (RBS). XPS measurements employ monochromatic Al K α radiation (hν = 1486.6 eV) to analyze V0.48Mo0.52N0.64(001) surfaces sputter-cleaned in-situ with 4 keV Ar+ ions incident at an angle of 70° with respect to the surface normal. XPS results show that the ion-etched sample surfaces have no measurable oxygen or carbon contamination; film composition, obtained using XPS sensitivity factors, is V0.33Mo0.67N0.64. All core level peaks, including the nearby Mo 3p3/2 (binding energy of 394.0 eV) and N 1s (at 397.6 eV) peaks, are well-resolved.

  • 270.
    Greczynski, Grzegorz
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Kindlund, Hanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Petrov, Ivan
    University of Illinois, Materials Science Department and Frederick Seitz Materials Research.
    Greene, Joseph E
    University of Illinois, Materials Science Department and Frederick Seitz Materials Research.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Sputter-cleaned Epitaxial VxMo(1-x)Ny/MgO(001)Thin Films Analyzed by X-ray PhotoelectronSpectroscopy: 3. Polycrystalline V0.49Mo0.51N1.022013In: Surface Science Spectra, ISSN 1055-5269, E-ISSN 1520-8575, Vol. 20, p. 80-85Article in journal (Refereed)
    Abstract [en]

    Vx Mo (1-x)Ny thin films grown by ultrahigh vacuum reactive magnetron sputter deposition on MgO(001) substrates are analyzed by x-ray photoelectron spectroscopy (XPS). This contribution presents analytical results for 300-nm-thick 002-textured polycrystalline V0.49 Mo 0.51N1.02 films deposited by reactive cosputtering from V (99.95 % purity) and Mo (99.95 % purity) targets. Film growth is carried out at 500 °C in mixed Ar/N2 atmospheres at a total pressure of 5 mTorr, with a N2 partial pressure of 3.2 mTorr; a bias of −30 V is applied to the substrate. Films composition is determined by Rutherford backscattering spectrometry (RBS). XPS measurements employ monochromatic Al K α radiation (hν = 1486.6 eV) to analyze V0.49 Mo 0.51N1.02 surface sputter-cleaned in-situ with 4 keV Ar+ ions incident at an angle of 70° with respect to the surface normal. XPS results show that the ion-etched sample surfaces have no measurable oxygen or carbon contamination; film composition, obtained using XPS sensitivity factors, is V0.34 Mo 0.66N1.00. All core level peaks, including the nearby Mo 3p3/2 (binding energy of 394.3 eV) and N 1s (at 397.4 eV) peaks, are well-resolved. Comparison to V0.33 Mo 0.67N0.64 and V0.34 Mo 0.66N0.81 single-crystal film surfaces, submitted separately to Surface Science Spectra, indicates that with decreasing growth temperature from 900 to 700 and 500 °C (and increasing nitrogen concentration in Vx Mo (1-x)Ny from y = 0.64 to 0.81 and 1.00) the N 1s core level peak shifts from 397.6 eV to 397.5 eV to 397.4 eV while metal atom peaks move towards higher binding energy by 0.2-0.4 eV.

  • 271.
    Alling, Björn
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultberg, L
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Abrikosov, Igor
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Strong electron correlations stabilize paramagnetic cubic Cr1-xAlxN solid solutions2013In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 102, no 3Article in journal (Refereed)
    Abstract [en]

    The stability of rock salt structure cubic Cr1-xAlxN solid solutions at high Al content and high temperature has made it one of the most important materials systems for protective coating applications. We show that the strong electron correlations in a material with dynamic magnetic disorder is the underlying reason for the observed stability against isostructural decomposition. This is done by using the first-principles disordered local moments molecular dynamics technique, which allows us to simultaneously consider electronic, magnetic, and vibrational degrees of freedom.

  • 272.
    Khatibi, Ali
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Genvad, Axel
    Sandvik Coromant AB, Materials and Processes R&D, Stockholm, Sweden.
    Göthelid, Emmanuelle
    Sandvik Coromant AB, Materials and Processes R&D, Stockholm, Sweden.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Structural and Mechanical Properties of (AlxCr1-x)2+yO3-y Coatings Grown by Reactive Cathodic Arc Evaporation in As-deposited and Annealed States2013In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 61, no 13, p. 4811-4822Article in journal (Refereed)
    Abstract [en]

    Coatings of (AlxCr1-x)2+yO3-y with 0.51≤x≤0.84 and 0.1≤y≤0.5 were deposited on hard cemented carbides substrates in an industrial cathodic arc evaporation system from powder-metallurgy prepared Cr/Al targets in pure O2 and O2+N2 atmospheres. The substrate temperature and bias in all the deposition runs were 575 °C and -120 V, respectively. The composition of the coatings measured by energy dispersive x-ray spectroscopy and elastic recoil detection analysis was the same as that of the targets. Microstructure analyses performed by symmetrical X-ray diffraction and transmission electron microscopy showed that corundum, cubic or mixed-phase coatings formed depending on the Cr/Al ratio of the coatings and O2 flow per activetarget during deposition. The corundum phase was promoted by high Cr content and high O2 flow per target, while the cubic phase was mostly observed for high Al content and low O2 flow per active target. In situ annealing of the cubic coatings resulted in phase transformation from cubic to corundum completed in the temperature range of 900-1100 °C, while corundum coatings retained their structure in the same range of annealing temperatures. Nanoindentation hardness of the coatings with Cr/Al ratio < 0.4 was 26-28 GPa, regardless of the structure. Increasing the Cr content of the coatings resulted in increased hardness of 28-30 GPa for corundum coatings. Wear resistance testing in a turning operation showed that coatings of Al-Cr-O have improved resistance to crater wear at the cost of flank wear compared to TiAlN coatings.

  • 273.
    Pettersson, Maria
    et al.
    Uppsala University, Sweden.
    Berlind, Torun
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Schmidt, Susann
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Jacobsson, Staffan
    Uppsala University, Sweden.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Persson, Cecilia
    Uppsala University, Sweden.
    Engqvist, Håkan
    Uppsala University, Sweden.
    Structure and composition of silicon nitride and silicon carbon nitride coatings for joint replacements2013In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 235, no 25, p. 827-834Article in journal (Refereed)
    Abstract [en]

    SiNx and SiCxNy coatings were fabricated with high power impulse magnetron sputtering (HiPIMS). The coatings microstructure, growth pattern, surface morphology, composition, and bonding structure were investigated by AFM, SEM, GIXRD, TEM, EDS as well as XPS, and related to the deposition parameters target powers and substrate temperature. Cross-sections of SiCxNy coatings showed either dense and laminar, or columnar structures. These coatings varied in roughness (Ra between 0.2 and 3.8 nm) and contained up to 35 at.% C. All coatings were substoichiometric (with an N/Si ratio from 0.27 to 0.65) and contained incorporated particles (so called droplets). The SiNx coatings, in particular those deposited at the lower power on the silicon target, demonstrated a dense microstructure and low surface roughness (Ra between 0.2 and 0.3 nm). They were dominated by an (X-ray) amorphous structure and consisted mainly of Si–N bonds. The usefulness of these coatings is discussed for bearing surfaces for hip joint arthroplasty in order to prolong their life-time. The long-term aim is to obtain a coating that reduces wear and metal ion release, that is biocompatible, and with wear debris that can dissolve in vivo.

  • 274.
    Furlan, Andrej
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Gueorguiev, Gueorgui Kostov
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Czigány, Zsolt
    Research Institute for Technical Physics and Materials Science, P.O. Box 49, Budapest, H-1525, Hungary.
    Darakchieva, Vanya
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Correia, Rosario
    I3N and Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Structure and properties of phosphorus-carbide thin solid films2013In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 548, no 2, p. 247-254Article in journal (Refereed)
    Abstract [en]

    Phosphorus-carbide (CPx) thin films have been deposited by unbalanced reactive magnetron sputtering and investigated by TEM, XPS, SEM, ERDA, Raman scattering spectroscopy, nanoindentation testing, and four-point electrical probe techniques. As-deposited films with x=0.1 are electron amorphous with elements of FL structure and high mechanical resiliency with hardness of 34.4 GPa and elastic recovery of 72%. The electrical resistivity of the films are in the range 0.4-1.7 Ωcm for CP0.027, 1.4-22.9 Ωcm for CP0.1, and lower than the minimal value the four-point probe is able to detect for CPx with x≥0.2.

  • 275.
    Junesand, Carl
    et al.
    KTH Royal Institute Technology, Sweden .
    Kataria, Himanshu
    KTH Royal Institute Technology, Sweden .
    Metaferia, Wondwosen
    KTH Royal Institute Technology, Sweden .
    Julian, Nick
    University of Calif Santa Barbara, CA USA .
    Wang, Zhechao
    KTH Royal Institute Technology, Sweden .
    Sun, Yan-Ting
    KTH Royal Institute Technology, Sweden .
    Bowers, John
    University of Calif Santa Barbara, CA USA .
    Pozina, Galia
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Lourdudoss, Sebastian
    KTH Royal Institute Technology, Sweden .
    Study of planar defect filtering in InP grown on Si by epitaxial lateral overgrowth2013In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 3, no 11, p. 1960-1973Article in journal (Refereed)
    Abstract [en]

    InP thin films have been grown on InP/Si substrate by epitaxial lateral overgrowth (ELOG). The nature, origin and filtering of extended defects in ELOG layers grown from single and double openings in SiO2 mask have been investigated. Whereas ELOG layers grown from double openings occasionally exhibit threading dislocations (TDs) at certain points of coalescence, TDs are completely absent in ELOG from single openings. Furthermore, stacking faults (SFs) observed in ELOG layers grown from both opening types originate not from coalescence, but possibly from formation during early stages of ELOG or simply propagate from the seed layer through the mask openings. A model describing their propagation is devised and applied to the existent conditions, showing that SFs can effectively be filtered under certain conditions. ELOG layers grown from identical patterns on InP substrate contained no defects, indicating that the defect-forming mechanism is in any case not inherent to ELOG itself.

  • 276.
    Mockuté, Aurelija
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Dahlqvist, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Emmerlich, Jens
    Rhein Westfal TH Aachen, Germany .
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Schneider, Jochen M
    Rhein Westfal TH Aachen, Germany .
    Persson, Per O A
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Synthesis and ab initio calculations of nanolaminated (Cr,Mn)2AlC compounds2013In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 87, no 9Article in journal (Refereed)
    Abstract [en]

    We present an ab initio theoretical analysis of the temperature-dependent stability of inherently nanolaminated (Cr1−xMnx)2AlC. The results indicate energetic stability over the composition range x = 0.0 to 0.5 for temperatures ≥600 K. Corresponding thin film compounds were grown by magnetron sputtering from four elemental targets. X-ray diffraction in combination with analytical transmission electron microscopy, including electron energy-loss spectroscopy and energy dispersive x-ray spectroscopy analysis, revealed that the films were epitaxial (0001)-oriented single-crystals with x up to 0.16.

  • 277.
    Alling, Björn
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Khatibi, Ali
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Simak, Sergey
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Theoretical investigation of cubic B1-like and corundum (Cr1−xAlx)2O3 solid solutions2013In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 31, no 3Article in journal (Refereed)
    Abstract [en]

    First-principles calculations are employed to investigate the stability and properties of cubic rock-salt-like (Cr1−xAlx)2O3 solid solutions, stabilized by metal site vacancies as recently reported experimentally. It is demonstrated that the metal site vacancies can indeed be ordered in a way that gives rise to a suitable fourfold coordination of all O atoms in the lattice. B1-like structures with ordered and disordered metal site vacancies are studied for (Cr0.5Al0.5)2O3 and found to have a cubic lattice spacing close to the values reported experimentally, in contrast to fluorite-like and perovskite structures. The obtained B1-like structures are higher in energy than corundum solid solutions for all compositions, but with an energy offset per atom similar to other metastable systems possible to synthesize with physical vapor deposition techniques. The obtained electronic structures show that the B1-like systems are semiconducting although with smaller band gaps than the corundum structure.

  • 278.
    Palisaitis, Justinas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hsiao, Ching-Lien
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Persson, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Thermal stability of Al1−xInxN (0 0 0 1) throughout the compositional range as investigated during in situ thermal annealing in a scanning transmission electron microscope2013In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 61, no 12, p. 4683-4688Article in journal (Refereed)
    Abstract [en]

    The thermal stability of Al1−xInxN (0 ⩽ ⩽ 1) layers was investigated by scanning transmission electron microscopy (STEM) imaging, electron diffraction, and monochromated valence electron energy loss spectroscopy during in situ annealing from 750 to 950 °C. The results show two distinct decomposition paths for the layers richest in In (Al0.28In0.72N and Al0.41In0.59N) that independently lead to transformation of the layers into an In-deficient, nanocrystalline and a porous structure. The In-richest layer (Al0.28In0.72N) decomposes at 750 °C, where the decomposition process is initiated by In forming at grain boundaries and is characterized by an activation energy of 0.62 eV. The loss of In from the Al0.41In0.59N layer was initiated at 800 °C through continuous desorption. No In clusters were observed during this decomposition process, which is characterized by an activation energy of 1.95 eV. Finally, layers richest in Al (Al0.82In0.18N and Al0.71In0.29N) were found to resist thermal annealing, although the initial stages of decomposition were observed for the Al0.71In0.29N layer.

  • 279.
    Vishnyakov, V
    et al.
    Manchester Metropolitan University, UK.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Colligon, J
    Manchester Metropolitan University, UK.
    Ti3SiC2-formation during Ti–C–Si multilayer deposition by magnetron sputtering at 650 °C2013In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 93, p. 56-59Article in journal (Refereed)
    Abstract [en]

    Titanium Silicon Carbide films were deposited from three separate magnetrons with elemental targets onto Si wafer substrates. The substrate was moved in a circular motion such that the substrate faces each magnetron in turn and only one atomic species (Ti, Si or C) is deposited at a time. This allows layer-by-layer film deposition. Material average composition was determined to Ti0.47Si0.14C0.39 by energy-dispersive X-ray spectroscopy. High-resolution transmission electron microscopy and Raman spectroscopy were used to gain insights into thin film atomic structure arrangements. Using this new deposition technique formation of Ti3SiC2 MAX phase was obtained at a deposition temperature of 650 °C, while at lower temperatures only silicides and carbides are formed. Significant sharpening of Raman E2g and Ag peaks associated with Ti3SiC2 formation was observed.

  • 280.
    Kindlund, Hanna
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Sangiovanni, Davide
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Martínez-de-Olcoz, L.
    Grupo de Capas Finas e Ingeniería de Superficies, Facultad de Física, Dep. Física Aplicada y Óptica, Universidad de Barcelona, Barcelona, Spain.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Petrov, Ivan
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology. Department of Materials Science and the Fredrick Seitz Materials Research Laboratory, University of Illinois, Urbana, USA.
    Greene, Joseph
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology. Department of Materials Science and the Fredrick Seitz Materials Research Laboratory, University of Illinois, Urbana, USA.
    Chirita, Valeriu
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Toughness Enhancement in Hard Ceramic Thin Films by Alloy Design2013In: APL MATERIALS, ISSN 2166-532X, Vol. 1, no 4, p. 042104-Article in journal (Refereed)
    Abstract [en]

    Hardness is an essential property for a wide range of applications. However, hardness alone, typically accompanied by brittleness, is not sufficient to prevent failure in ceramic films exposed to high stresses. Using VN as a model system, we demonstrate with experiment and density functional theory (DFT) that refractory VMoN alloys exhibit not only enhanced hardness, but dramatically increased ductility. V0.5Mo0.5N hardness is 25% higher than that of VN. In addition, while nanoindented VN, as well as TiN reference samples, suffer from severe cracking typical of brittle ceramics, V0.5Mo0.5N films do not crack. Instead, they exhibit material pile-up around nanoindents, characteristic of plastic flow in ductile materials. Moreover, the wear resistance of V0.5Mo0.5N is considerably higher than that of VN. DFT results show that tuning the occupancy of d-t2g metallic bonding states in VMoN facilitates dislocation glide, and hence enhances toughness, via the formation of stronger metal/metal bonds along the slip direction and weaker metal/N bonds across the slip plane.

  • 281.
    Broitman, Esteban
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Tribology of Carbon-Based Coatings: Past, Present, and Future2013In: Proceeding of the 2nd International Workshop of Tribology Tribaries 2013, 2013, p. 7-10Conference paper (Other academic)
    Abstract [en]

    In this talk, the development of carbon-based coatings will be reviewed. The most recent findings in the synthesis, characterization and application of carbon-based coatings will be highlighted. Future perspectives of new fullerene-like carbon-based tribological coatings will be discussed. Novel applications of fullerene-like CNx, CPx, and CFx will be envisioned.

  • 282.
    Tholander, Christopher
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Abrikosov, Igor
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Tasnadi, Ferenc
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Volume matching condition to establish the enhanced piezoelectricity in ternary (Sc,Y)0.5(Al,Ga,In)0.5N alloys2013In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 87, no 9Article in journal (Refereed)
    Abstract [en]

    Recently, ScAlN alloys attracted attention for their giant piezoelectric moduli. In this study the piezoelectric response of the wurtzite group-III nitrides AlN, GaN, and InN mixed with 50 mol% of ScN or YN is investigated using ab initio calculations. We confirm that the energy flattening phenomenon gives rise to the simultaneous appearance of elastic softening and local structural instability, and explains the enhanced piezoelectricity of the alloys. Furthermore, we present a volume matching condition for an efficient search of new piezoelectric materials. It states that alloys in which the parent components show close volume matching exhibit a flatter potential-energy landscape and higher increase of piezoelectric moduli. We suggest YInN, beyond ScAlN, as a promising material for piezoelectric energy harvesting with its enhanced ≈400% piezoelectric moduli.

  • 283.
    Bigault, Thierry
    et al.
    Institut Laue Langevin, Grenoble, Cedex 9, France.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Buffet, J. C.
    Institut Laue Langevin, Grenoble, Cedex 9, France.
    Correa, Jonathan
    Institut Laue Langevin, Grenoble, Cedex 9, France.
    Hall-Wilton, Richard
    European Spallation Source ESS AB, Lund, Sweden.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Höglund, Carina
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Guérard, Bruno
    Institut Laue Langevin, Grenoble, Cedex 9, France.
    Khaplanov, Anton
    Institut Laue Langevin, Grenoble, Cedex 9, France.
    Piscitelli, Fransesco
    Institut Laue Langevin, Grenoble, Cedex 9, France.
    van Esch, P.
    Institut Laue Langevin, Grenoble, Cedex 9, France.
    10B multi-grid proportional gas counters for large area thermal neutron detectors2012In: Neutron News, ISSN 1044-8632, E-ISSN 1931-7352, Vol. 23, no 4, p. 20-24Article in journal (Refereed)
  • 284.
    Broitman, Esteban
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Adhesion improvement of carbon-based coatings through a high ionization deposition technique2012In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 370, no 012009Article in journal (Refereed)
    Abstract [en]

    The deposition of highly adherent carbon nitride (CNx) films using a pretreatment with two high power impulse magnetron sputtering (HIPIMS) power supplies in a master-slave configuration is reviewed. SKF3 (AISI 52100) steel substrates were pretreated in the environment of a high ionized Cr+Ar plasma in order to sputter clean the surface and implant Cr metal ions. CNx films were subsequently deposited at room temperature by DC magnetron sputtering from a high purity C target in a N-2/Ar plasma discharge. All processing was done in an industrial-scale CemeCon CC800 coating system. A series of depositions were obtained with samples pretreated at different bias voltages (DC and pulsed). The adhesion of CNx films, evaluated by the Daimler-Benz Rockwell-C test, reaches strength quality HF1. Adhesion results are correlated to high resolution transmission electron microscopy observations confirming the formation of an optimal interfacial mixing layer of Cr and steel. The throwing power increase for HIPIMS coatings is associated to the higher ionization in the plasma discharge.

  • 285.
    Eriksson, Anders
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Ghafoor, Naureen
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Näslund, Lars-Åke
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Johansson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Sjölen, J.
    Seco Tools AB, Fagersta, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Arc deposition of Ti–Si–C–N thin films from binary and ternary cathodes — Comparing sources of C2012In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 213, p. 145-154Article in journal (Refereed)
    Abstract [en]

    Ti–Si–C–N thin films with composition of 1–11 at.% Si and 1–20 at.% C have been deposited onto cemented carbide substrates by arcing Ti–Si cathodes in a CH4 + N2 gas mixture and, alternatively, through arcing Ti–Si–C cathodes in N2. Films of comparable compositions from the two types of cathodes have similar structure and properties. Hence, C can be supplied as either plasma ions generated from the cathode or atoms from the gas phase with small influence on the structural evolution. Over the compositional range obtained, the films were dense and cubic-phase nanocrystalline, as characterized by X-ray diffraction, ion beam analysis, and scanning and transmission electron microscopy. The films have high hardness (30–40 GPa by nanoindentation) due to hardening from low-angle grain boundaries on the nanometer scale and lattice defects such as growth-induced vacancies and alloying element interstitials.

  • 286.
    Höglund, Carina
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Andersen, Ken
    European Spallat Source ESS AB, Sweden .
    Bigault, Thierry
    Institute Max Von Laue Paul Langevin, France .
    Buffet, Jean-Claude
    Institute Max Von Laue Paul Langevin, France .
    Correa, Jonathan
    Institute Max Von Laue Paul Langevin, France .
    van Esch, Patrick
    Institute Max Von Laue Paul Langevin, France .
    Guerard, Bruno
    Institute Max Von Laue Paul Langevin, France .
    Hall-Wilton, Richard
    European Spallat Source ESS AB, Sweden .
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Khaplanov, Anton
    European Spallat Source ESS AB, Sweden Institute Max Von Laue Paul Langevin, France .
    Piscitelli, Francesco
    Institute Max Von Laue Paul Langevin, France .
    Vettier, Christian
    European Spallat Source ESS AB, Sweden European Synchrotron Radiat Facil, France .
    Vollenberg, Wilhelmus
    CERN, Switzerland .
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    B4C thin films for neutron detection2012In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 111, no 10, p. 104908-Article in journal (Refereed)
    Abstract [en]

    Due to the very limited availability of He-3, new kinds of neutron detectors, not based on 3He, are urgently needed. Here, we present a method to produce thin films of (B4C)-B-10, with maximized detection efficiency, intended to be part of a new generation of large area neutron detectors. B4C thin Films have been deposited onto Al-blade and Si wafer substrates by dc magnetron sputtering from (B4C)-B-nat and (B4C)-B-10 targets in an Ar discharge, using an industrial deposition system. The films were characterized with scanning electron microscopy, elastic recoil detection analysis, x-ray reflectivity, and neutron radiography. We show that the film-substrate adhesion and film purity are improved by increased substrate temperature and deposition rate. A deposition rate of 3.8 angstrom/s and substrate temperature of 400 degrees C result in films with a density close to bulk values and good adhesion to film thickness above 3 mu m. Boron-10 contents of almost 80 at. % are obtained in 6.3 m(2) of 1 mu m thick (B4C)-B-10 thin films coated on Al-blades. Initial neutron absorption measurements agree with Monte Carlo simulations and show that the layer thickness, number of layers, neutron wavelength, and amount of impurities are determining factors. The study also shows the importance of having uniform layer thicknesses over large areas, which for a full-scale detector could be in total similar to 1000 m(2) of two-side coated Al-blades with similar to 1 mu m thick (B4C)-B-10 films.

  • 287.
    Lane, Nina J
    et al.
    Drexel University, USA .
    Naguib, Michael
    Drexel University,USA .
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Barsoum, Michel W
    Drexel University, USA .
    Comment on "Ti5Al2C3: A New Ternary Carbide Belonging to MAX Phases in the Ti-Al-C System"2012In: Journal of The American Ceramic Society, ISSN 0002-7820, E-ISSN 1551-2916, Vol. 95, no 10, p. 3352-3354Article in journal (Refereed)
    Abstract [en]

    n/a

  • 288.
    Sun, Jianwu W.
    et al.
    Université Montpellier 2 and CNRS, France.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Mexis, M.
    Université Montpellier 2 and CNRS, France .
    Eriksson, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Tsiaoussis, I.
    Aristotle University of Thessaloniki, Greece.
    Yazdi, Gholamreza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Peyre, H.
    Université Montpellier 2 and CNRS, France.
    Juillaguet, S.
    Université Montpellier 2 and CNRS, France.
    Camassel, J.
    Université Montpellier 2 and CNRS, France.
    Holtz, Per-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Comparative micro-photoluminescence investigation of ZnO hexagonal nanopillars and the seeding layer grown on 4H-SiC2012In: Journal of Luminescence, ISSN 0022-2313, E-ISSN 1872-7883, Vol. 132, no 1, p. 122-127Article in journal (Refereed)
    Abstract [en]

    We report on a comparative micro-photoluminescence investigation of ZnO hexagonal nanopillars (HNPs) and the seeding layer grown on the off-axis 4H-SiC substrate. Transmission electron microscope (TEM) results establish that a thin seeding layer continuously covers the terraces of 4H-SiC prior to the growth of ZnO HNPs. Low temperature photoluminescence (LTPL) shows that ZnO HNPs are only dominated by strong donor bound exciton emissions without any deep level emissions. Micro-LTPL mapping demonstrates that this is specific also for the seeding layer. To further understand the recombination mechanisms, time-resolved micro-PL spectra (micro-TRPL) have been collected at 5 K and identical bi-exponential decays have been found on both the HNPs and seeding layer. Temperature-dependent TRPL indicates that the decay time of donor bound exciton is mainly determined by the contributions of non-radiative recombinations. This could be explained by the TEM observation of the non-radiative defects in both the seeding layer and HNPs, like domain boundaries and dislocations, generated at the ZnO/SiC interface due to biaxial strain.

  • 289.
    Alling, Björn
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Steneget, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Tholander, Christopher
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Tasnádi, Ferenc
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Petrov, Ivan
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Greene, Joseph E
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Configurational disorder effects on adatom mobilities on Ti1-xAlxN(001) surfaces from first principles2012In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 85, no 24, p. 245422-Article in journal (Refereed)
    Abstract [en]

    We use metastable NaCl-structure Ti0.5Al0.5N alloys to probe effects of configurational disorder on adatom surface diffusion dynamics which control phase stability and nanostructural evolution during film growth. First-principles calculations were employed to obtain energy potential maps of Ti and Al adsorption on an ordered TiN(001) reference surface and a disordered Ti0.5Al0.5N(001) solid-solution surface. The energetics of adatom migration on these surfaces are determined and compared to isolate effects of configurational disorder. The results show that alloy surface disorder dramatically reduces Ti adatom mobilities. Al adatoms, in sharp contrast, experience only small disorder-induced differences in migration dynamics.

  • 290.
    Gunnarsson Sarius, Niklas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Lauridsen, Jonas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Lewin, E.
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Sweden.
    Jansson, U.
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Sweden.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Öberg, Å.
    ABB Corporate Research, Forskargränd 7, SE-721 78 Västerås, Sweden.
    Leisner, P.
    SP Technical Research Institute of Sweden, Box 857, 501 15 Borås, Sweden/School of Engineering Jönköping University, Sweden.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Contact resistance of Ti-Si-C-Ag and Ti-Si-C-Ag-Pd nanocomposite coatings2012In: Journal of Electronic Materials, ISSN 0361-5235, E-ISSN 1543-186X, Vol. 41, no 3, p. 560-567Article in journal (Refereed)
    Abstract [en]

    Ti-Si-C-Ag-Pd and Ti-Si-C-Ag nanocomposite coatings were deposited by magnetronsputtering on Cu substrates with an electroplated Ni layer. Analytical electronmicroscopy and x-ray diffraction show that the nanocomposites consist of TiC,Ag:Pd, and amorphous SiC. The contact resistance of these coatings against aspherical Au-Co surface was measured for applied contact force up 0 to 5 N. Ti-Si-CAg-Pd coatings with a Ag:Pd strike coating has ~10 times lower contact resistance atcontact forces below 1 N (~10 mΩ at ~0.1N), and ~2 times lower for contact forcesaround 5 N (<1 mΩ at 5 N), compared to the Ti-Si-C-Ag coating.

  • 291.
    Zainelabdin, Ahmed
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Amin, Gul
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zaman, Siama
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    CuO/ZnO Nanocorals synthesis via hydrothermal technique: growth mechanism and their application as Humidity Sensor2012In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 22, no 23, p. 11583-11590Article in journal (Refereed)
    Abstract [en]

    We demonstrate hydrothermal synthesis of coral-like CuO nanostructures by selective growth on ZnO nanorods (NR) at low temperatures. During the hydrothermal processing the resultant hydroxylated and eroded surface of ZnO NR becomes favorable for the CuO nanostructures growth via oriented attachments. Heterojunction p-n diodes fabricated from the CuO/ZnO nanocorals (NC) reveal stable and high rectification diode properties with a turn-on voltage ~1.52 V and negligible reverse current. The humidity sensing characteristics of the CuO/ZnO NC diodes exhibit a remarkable linear (in a semilogarithmic scale) decrease in the DC resistance by more than three orders when the relative humidity is changed from 30 – 90 %. The NC humidity sensor is also found to reveal the highest sensitivity factor ~6045 among available data for the constituent material’s and a response and recovery time of 6 s and 7 s, respectively.

  • 292.
    Hsiao, Ching-Lien
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Magnusson, Roger
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Palisaitis, Justinas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Sandström, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Valyukh, Sergiy
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Persson, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Järrendahl, Kenneth
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Curved-lattice epitaxial growth of chiral AlInN twisted nanorods for optical applications2012Manuscript (preprint) (Other academic)
    Abstract [en]

    Despite of using chiral metamaterials to manipulate light polarization states has been demonstrated their great potential for applications such as invisible cloaks, broadband or wavelength-tunable circular polarizers, microreflectors, etc. in the past decade [1-6], operating wavelength in ultraviolet-visible range is still a challenge issue. Since these chiral structures often consist of metallic materials, their operation is designed for the infrared and microwave regions [2-4]. Here, we show how a controlled curved-lattice epitaxial growth (CLEG) of wide-bandgap AlInN semiconductor curved nanocrystals [7] can be exploited as a novel route for tailoring chiral nanostructures in the form of twisted nanorods (TNRs). The fabricated TNRs are shown to reflect light with a high degree of polarization as well as a high degree of circular polarization (that is, nearly circularly polarized light) in the ultravioletvisible region. The obtained polarization is shown to be dependent on the handedness of the TNRs.

  • 293.
    Pearce, Ruth
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, Faculty of Science & Engineering.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Eriksson, Johan
    Linköping University, Department of Physics, Chemistry and Biology, Surface and Semiconductor Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Andersson, Mike
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Development of FETs and resistive devices based on epitaxially grown single layer graphene on SiC for highly sensitive gas detection2012In: Materials Science Forum Vols 717 - 720, Trans Tech Publications Inc., 2012, Vol. 717-720, p. 687-690Conference paper (Refereed)
    Abstract [en]

    Epitaxially grown single layer graphene on silicon carbide (SiC) resistive sensors were characterised for NO2 response at room and elevated temperatures, with an n-p type transition observed with increasing NO2 concentration for all sensors. The concentration of NO2 required to cause this transition varied for different graphene samples and is attributed to varying degrees of substrate induced Fermi-level (E-F) pinning above the Dirac point. The work function of a single layer device increased steadily with increasing NO2 concentration indicating no change in reaction mechanism for high and low concentrations despite a change in sensor response direction. Epitaxially grown graphene device preparation is challenging due to poor adhesion of the graphene layer to the substrate. A field effect transistor (FET) device is presented which does not require wire bonding to contacts on graphene.

  • 294.
    Eklund, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Dahlqvist, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Tengstrand, Olof
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Nedfors, Nils
    Uppsala University, Sweden .
    Jansson, Ulf
    Uppsala University, Sweden .
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Discovery of the Ternary Nanolaminated Compound Nb2GeC by a Systematic Theoretical-Experimental Approach2012In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 109, no 3, p. 035502-Article in journal (Refereed)
    Abstract [en]

    Since the advent of theoretical materials science some 60 years ago, there has been a drive to predict and design new materials in silicio. Mathematical optimization procedures to determine phase stability can be generally applicable to complex ternary or higher-order materials systems where the phase diagrams of the binary constituents are sufficiently known. Here, we employ a simplex-optimization procedure to predict new compounds in the ternary Nb-Ge-C system. Our theoretical results show that the hypothetical Nb2GeC is stable, and excludes all reasonably conceivable competing hypothetical phases. We verify the existence of the Nb2GeC phase by thin film synthesis using magnetron sputtering. This hexagonal nanolaminated phase has a and c lattice parameters of similar to 3.24 angstrom and 12.82 angstrom.

  • 295.
    Sangiovanni, Davide
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Edström, Daniel
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Chirita, Valeriu
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Petrov, Ivan
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Greene, Joseph E
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Dynamics of Ti, N, and TiNx (x=1-3) admolecule transport on TiN(001) surfaces2012In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 86, no 15, p. 155443-Article in journal (Refereed)
    Abstract [en]

    We use classical molecular dynamics and the modified embedded atom method formalism to investigate the dynamics of atomic-scale transport on a low-index model compound surface, TiN(001). Our simulations, totaling 0.25 mu s for each case study, follow the pathways and migration kinetics of Ti and N adatoms, as well as TiNx complexes with x = 1-3, which are known to contribute to the growth of TiN thin films by reactive deposition from Ti, N-2, and N precursors. The simulations are carried out at 1000 K, within the optimal range for TiN(001) epitaxial growth. We find Ti adatoms to be the highest-mobility species on TiN(001), with the primary migration path involving jumps of one nearest-neighbor distance d(NN) between adjacent fourfold hollow sites along in-plane andlt; 100 andgt; channels. Long jumps, 2d(NN), are also observed, but at much lower frequency. N adatoms, which exhibit significantly lower migration rates than Ti, diffuse along in-plane andlt; 110 andgt; directions and, when they intersect other N atoms, associatively form N-2 molecules, which desorb at kinetic rates. As expected, TiN and TiN3 complexes migrate at even lower rates with complex diffusion pathways involving rotations, translations, and rototranslations. TiN2 trimers, however, are shown to have surprisingly high diffusion rates, above that of N adatoms and almost half that of Ti adatoms. TiN3 motion is dominated by in-place rotation with negligible diffusion.

  • 296.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Editorial2012In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 86, no 8, p. 1013-1013Article in journal (Other academic)
    Abstract [en]

    n/a

  • 297.
    Junesand, Carl
    et al.
    KTH, Sweden .
    Hu, Chen
    KTH, Sweden .
    Wang, Zhechao
    KTH, Sweden .
    Metaferia, Wondwosen
    KTH, Sweden .
    Dagur, Pritesh
    KTH, Sweden .
    Pozina, Galia
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Lourdudoss, Sebastian
    KTH, Sweden .
    Effect of the Surface Morphology of Seed and Mask Layers on InP Grown on Si by Epitaxial Lateral Overgrowth2012In: Journal of Electronic Materials, ISSN 0361-5235, E-ISSN 1543-186X, Vol. 41, no 9, p. 2345-2349Article in journal (Refereed)
    Abstract [en]

    Heteroepitaxy of InP on Si by epitaxial lateral overgrowth (ELOG) using a thin seed layer of InP as starting material is investigated, with special attention given to the effect of the surface morphology of the seed and the mask layers on the quality of the ELOG layers. Chemical mechanical polishing (CMP) has been used to improve the morphological and optical quality of InP grown by hydride vapor-phase epitaxy (HVPE) using ELOG. Two approaches have been investigated: polishing the InP seed layer on Si before depositing the SiO2 mask and polishing the SiO2 mask after its deposition on the unprocessed seed layer. For polishing the InP (seed)/Si, a two-step process with an aluminum oxide- and sodium hypochlorite-containing slurry as well as a slurry based on sodium hypochlorite mixed with citric acid was used. For SiO2 mask polishing, a slurry with colloidal silica as an abrasive was employed. In both cases, the SiO2 mask was patterned with double line openings and ELOG carried out in an HVPE reactor. Morphology and crystal quality of the resulting ELOG layers were studied with atomic force microscopy (AFM) and room-temperature panchromatic cathodoluminescence (PC-CL) in situ in a scanning electron microscope (SEM), respectively. The results show that, whereas both polishing approaches result in an ELOG InP layer with good morphology, its surface roughness is lower when the InP (seed)/Si is subjected to CMP prior to deposition of the SiO2 mask, than when only the SiO2 mask is polished. This approach also leads to a decrease in the number of defects generated during coalescence of the ELOG layers.

  • 298.
    Lauridsen, Jonas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Furlan, A.
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, P.O. Box 538, SE-751 21 Uppsala, Sweden.
    Flink, A.
    Impact Coatings AB, Westmansgatan 29, SE-582 16 Linköping, Sweden.
    Andersson, A. M.
    ABB Corporate Research, Forskargränd 7, SE-721 78, Västerås, Sweden.
    Jansson, U.
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, P.O. Box 538, SE-751 21 Uppsala, Sweden.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Effects of A-elements (A = Si, Ge or Sn) on the structure and electrical contact properties of Ti-A-C-Ag nanocomposites2012In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 520, no 16, p. 5128-5136Article in journal (Refereed)
    Abstract [en]

    Ti-A-C-Ag (A is Si, Ge or Sn) nanocomposite coatings have been deposited by dc magnetron sputtering in an ultra high vacuum chamber. Electron microscopy, energy-dispersive x-ray spectroscopy, xray photoelectron spectroscopy, and x-ray diffraction show that all coatings contain nanocrystalline TiC and Ag grains in a matrix of mainly amorphous C. A C/Ti ratio above unity yields a homogenous distribution of Ag with a reduced grain size. From a chemical point of view, the addition of Ge and Sn to the Ti-C-Ag system should increase the conductivity of the coatings since the formation of more metallic phases than Si. We demonstrate that Si can be replaced with Ge and Sn and still yield a homogeneous distribution of Ag. The incorporation of Ge and Sn to the Ti-C-Ag system results in elemental precipitation and intermetallic phases, respectively. This gives improved electrical properties compared to Ti-Si-C-Ag coatings, and a contact resistance at loads of ~1 N against an Au probe (radius of 0.7 mm) that is comparable to that of Ag.

  • 299.
    Xie, Mengyao
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Tasnadi, Ferenc
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Abrikosov, Igor
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Darakchieva, Vanya
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Elastic constants, composition, and piezolectric polarization in InxAl1-xN: From ab initio calculations to experimental implications for the applicability of Vegards rule2012In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 86, no 15, p. 155310-Article in journal (Refereed)
    Abstract [en]

    We present a theoretical analysis on the applicability of Vegards linear rule in InxAl1-xN alloys in relation to strain related elastic and piezoelectric properties. We derive the elastic stiffness constants and biaxial coefficients, as well as the respective deviations from linearity (Vegards rule) by using ab initio calculations. The stress-strain relationships to extract composition from the lattice parameters are derived in different coordinate systems for InxAl1-xN with an arbitrary surface orientation. The error made in the composition extracted from the lattice parameters if the deviations from linearity are not taken into account is discussed for different surface orientations, compositions and degrees of strain in the InxAl1-xN films. The strain induced piezoelectric polarization is analyzed for InxAl1-xN alloys grown pseudomorphically on GaN. The polarization values are compared with those obtained from our experimental data for the lattice parameters. We establish the importance of the deviation from linearity to correctly determine the piezoelectric polarization and also a smooth, not particular piezoelectric response at GaN lattice matched conditions.

  • 300.
    Magnuson, Martin
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Andersson, Matilda
    Uppsala University.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Jansson, Ulf
    Uppsala University.
    Electronic Structure and Chemical Bonding of AmorphousChromium Carbide Thin Films2012In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 24, p. 225004-Article in journal (Refereed)
    Abstract [en]

    The microstructure, electronic structure, and chemical bonding of chromium carbidethin films with different carbon contents have been investigated with high-resolutiontransmission electron microscopy, electron energy loss spectroscopy and soft x-rayabsorption-emission spectroscopies. Most of the films can be described as amorphousnanocomposites with non-crystalline CrCx in an amorphous carbon matrix. At highcarbon contents, graphene-like structures are formed in the amorphous carbon matrix.At 47 at% carbon content, randomly oriented nanocrystallites are formed creating acomplex microstructure of three components. The soft x-ray absorption-emissionstudy shows additional peak structures exhibiting non-octahedral coordination andbonding.

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