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  • 1.
    Alami, Jones
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating 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.
    Andersson, Jon M.
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics . Linköping University, The Institute of Technology.
    Lattemann, Martina
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Wallin, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics . Linköping University, The Institute of Technology.
    Böhlmark, Johan
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating 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.
    Helmersson, Ulf
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics . Linköping University, The Institute of Technology.
    Phase tailoring of Ta thin films by highly ionized pulsed magnetron sputtering2007In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 7-8, p. 3434-3438Article in journal (Refereed)
    Abstract [en]

    Ta thin films were grown on Si substrates at different inclination angles with respect to the sputter source using high power impulse magnetron sputtering (HIPIMS), an ionized physical vapor deposition technique. The ionization allowed for better control of the energy and directionality of the sputtered species, and consequently for improved properties of the deposited films. Depositions were made on Si substrates with the native oxide intact. The structure of the as deposited films was investigated using X-ray diffraction, while a four-point probe setup was used to measure the resistivity. A substrate bias process-window for growth of bcc-Ta was observed. However, the process-window position changed with changing inclination angles of the substrate. The formation of this low-resistivity bcc-phase could be understood in light of the high ion flux from the HIPIMS discharge.

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  • 2.
    Alami, Jones
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating 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.
    Emmerlich, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Wilhelmsson, O.
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Uppsala, Sweden.
    Jansson, U.
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Uppsala, Sweden.
    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.
    Helmersson, Ulf
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, The Institute of Technology.
    High-power impulse magnetron sputtering of Ti-Si-C thin films from a Ti3SiC2 compound target2006In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 4, p. 1731-1736Article in journal (Refereed)
    Abstract [en]

    We have deposited Ti-Si-C thin films using high-power impulse magnetron sputtering (HIPIMS) from a Ti3SiC2 compound target. The as-deposited films were composite materials with TiC as the main crystalline constituent. X-ray diffraction and photoelectron spectroscopy indicated that they also contained amorphous SiC, and for films deposited on inclined substrates, crystalline Ti5Si3Cx. The film morphology was dense and flat, while films deposited with dc magnetron sputtering under comparable conditions were rough and porous. Due to the high degree of ionization of the sputtered species obtained in HIPIMS, it is possible to control the film composition, in particular the C content, by tuning the substrate inclination angle, the Ar process pressure, and the bias voltage.

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  • 3.
    Ali, Sharafat
    et al.
    Linnaeus Univ, Sweden.
    Magnusson, Roger
    Linnaeus Univ, Sweden.
    Pshyk, Oleksandr
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Empa Swiss Fed Labs Mat Sci & Technol, Switzerland.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Le Febvrier, Arnaud
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Effect of O/N content on the phase, morphology, and optical properties of titanium oxynitride thin films2023In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 58, p. 10975-10985Article in journal (Refereed)
    Abstract [en]

    Phase formation, morphology, and optical properties of Ti(O,N) thin films with varied oxygen-to- nitrogen ration content were investigated. The films were deposited by magnetron sputtering at 500 & DEG;C on Si(100) and c-plane sapphire substrate. A competition between a NaCl B1 structure TiN1-xOx, a rhombohedral structure Ti-2(O1-yNy)(3), and an anatase structure Ti(O1-zNz)(2) phase was observed. While the N-rich films were composed of a NaCl B1 TiN1-xOx phase, an increase of oxygen in the films yields the growth of rhombohedral Ti-2(O1-yNy)(3) phase and the oxygen-rich films are comprised of a mixture of the rhombohedral Ti-2(O1-yNy)(3) phase and anatase Ti(O1-zNz)(2) phase. The optical properties of the films were correlated to the phase composition and the observation of abrupt changes in terms of refractive index and absorption coefficient. The oxide film became relatively transparent in the visible range while the addition of nitrogen into films increases the absorption. The oxygen rich-samples have bandgap values below 3.75 eV, which is higher than the value for pure TiO2, and lower than the optical bandgap of pure TiN. The optical properties characterizations revealed the possibility of adjusting the band gap and the absorption coefficient depending on the N-content, because of the phases constituting the films combined with anionic substitution.

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  • 4.
    Ali, Sharafat
    et al.
    Linnaeus University, Sweden; Corning Inc, NY 14831 USA.
    Paul, Biplab
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Magnusson, Roger
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Broitman, Esteban
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Jonson, Bo
    Linnaeus University, Sweden.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Synthesis and characterization of the mechanical and optical properties of Ca-Si-O-N thin films deposited by RF magnetron sputtering2017In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 315, p. 88-94Article in journal (Refereed)
    Abstract [en]

    Ca-Si-O-N thin films were deposited on commercial soda-lime silicate float glass, silica wafers and sapphire substrates by RF magnetron co-sputtering from Ca and Si targets in an Ar/N-2/O-2 gas mixture. Chemical composition, surface morphology, hardness, reduced elastic modulus and optical properties of the films were investigated using X-ray photoelectron spectroscopy, scanning electron microscopy, nanoindentation, and spectroscopic ellipsometry. It was found that the composition of the films can be controlled by the Ca target power, predominantly, and by the reactive gas flow. Thin films in the Ca-Si-O-N system are composed of N and Ca contents up to 31 eq. % and 60 eq. %, respectively. The films thickness ranges from 600 to 3000 nm and increases with increasing Ca target power. The films surface roughness varied between 2 and 12 nm, and approximately decreases with increasing power of Ca target. The hardness (4-12 GPa) and reduced elastic modulus (65-145 GPa) of the films increase and decrease with the N and Ca contents respectively. The refractive index (1.56-1.82) is primarily dictated by the N content. The properties are compared with findings for bulk glasses in the Ca-Si-(Al)-O-N systems, and it is concluded that Ca-Si-O-N thin films have higher values of hardness, elastic modulus and refractive index than bulk glasses of similar composition. (C) 2017 Elsevier B.V. All rights reserved.

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  • 5.
    Ali, Sharafat
    et al.
    Linnaeus Univ, Sweden.
    Paul, Biplab
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Magnusson, Roger
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Ekström, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Pallier, Camille
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. RISE IVF, S-58188 Linkoping, Sweden.
    Jonson, Bo
    Linnaeus Univ, Sweden.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Optical and mechanical properties of amorphous Mg-Si-O-N thin films deposited by reactive magnetron sputtering2019In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 372, p. 9-15Article in journal (Refereed)
    Abstract [en]

    In this work, amorphous thin films in Mg-Si-O-N system typically containing amp;gt; 15 at.% Mg and 35 at.% N were prepared in order to investigate especially the dependence of optical and mechanical properties on Mg composition. Reactive RF magnetron co-sputtering from magnesium and silicon targets were used for the deposition of Mg-Si-O-N thin films. Films were deposited on float glass, silica wafers and sapphire substrates in an Ar, N-2 and O-2 gas mixture. X-ray photoelectron spectroscopy, atomic force microscopy, scanning electron microscopy, spectroscopic ellipsometry, and nanoindentation were employed to characterize the composition, surface morphology, and properties of the films. The films consist of N and Mg contents up to 40 at.% and 28 at.%, respectively and have good adhesion to substrates and are chemically inert. The thickness and roughness of the films increased with increasing content of Mg. Both hardness (16-21 GPa) and reduced elastic modulus (120-176 GPa) are strongly correlated with the amount of Mg content. The refractive index up to 2.01 and extinction coefficient up to 0.18 were found to increase with Mg content. The optical band gap (3.1-4.3) decreases with increasing the Mg content. Thin film deposited at substrate temperature of 100 degrees C shows a lower value of hardness (10 GPa), refractive index (1.75), and higher values of reduced elastic modulus (124 GPa) as compared to the thin film deposited at 310 degrees C and 510 degrees C respectively, under identical synthesis parameters.

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  • 6.
    Ali, Sharafat
    et al.
    Linnaeus University, Sweden.
    Paul, Biplab
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Magnusson, Roger
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, Faculty of Science & Engineering.
    Greczynski, Grzegorz
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Broitman, Esteban
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Jonson, Bo
    Linnaeus University, Sweden.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Novel transparent Mg-Si-O-N thin films with high hardness and refractive index2016In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 131Article in journal (Refereed)
    Abstract [en]

    There is an increasing demand for glass materials with better mechanical and optical properties for display and electronic applications. This paper describes the deposition of novel thin films of Mg-circle divide-Si-O-N onto float glass substrates. Amorphous thin films in the Mg-Si-O-N system with high nitrogen and magnesium contents were deposited by reactive RF magnetron co-sputtering from Mg and Si targets in Ar/N-2/O-2 gas mixtures. The thin films studied span an unprecedented range of compositions up to 45 at% Mg and 80 at% N out of cations and anions respectively. Thin films in the Mg-Si-O-N system were found to be homogeneous and transparent in the visible region. Mechanical properties like hardness (H) and reduced elastic modulus (Er) show high values, up to 21 GPa and 166 GPa respectively. The refractive index (1.87-2.00) increases with increasing magnesium and nitrogen contents. (C) 2016 Elsevier Ltd. All rights reserved.

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  • 7.
    Alijan Farzad Lahiji, Faezeh
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Bairagi, Samiran
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Magnusson, Roger
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Sortica, Mauricio A.
    Uppsala Univ, Sweden.
    Primetzhofer, Daniel
    Uppsala Univ, Sweden.
    Ekström, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Paul, Biplab
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Le Febvrier, Arnaud
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Growth and optical properties of NiO thin films deposited by pulsed dc reactive magnetron sputtering2023In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 41, no 6, article id 063402Article in journal (Refereed)
    Abstract [en]

    NiO thin films with varied oxygen contents are grown on Si(100) and c-Al2O3 at a substrate temperature of 300 degrees C using pulsed dc reactive magnetron sputtering. We characterize the structure and optical properties of NiO changes as functions of the oxygen content. NiO with the cubic structure, single phase, and predominant orientation along (111) is found on both substrates. X-ray diffraction and pole figure analysis further show that NiO on the Si(100) substrate exhibits fiber-textured growth, while twin domain epitaxy was achieved on c-Al2O3, with NiO(111) k Al2O3(0001) and NiO[1 (1) over bar0]k Al2O3[10 (1) over bar0] or NiO[(1) over bar 10]k Al2O3[2 (1) over bar(1) over bar0] epitaxial relationship. The oxygen content in NiO films did not have a significant effect on the refractive index, extinction coefficient, and absorption coefficient. This suggests that the optical properties of NiO films remained unaffected by changes in the oxygen content.

  • 8.
    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 solutionsManuscript (preprint) (Other academic)
    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 favorable 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 a have 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.

  • 9.
    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.

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  • 10.
    Anasori, Babak
    et al.
    Drexel University, PA 19104 USA; Drexel University, PA 19104 USA.
    Dahlqvist, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Halim, Joseph
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Drexel University, PA 19104 USA.
    Ju Moon, Eun
    Drexel University, PA 19104 USA.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hosler, Brian C.
    Drexel University, PA 19104 USA.
    Caspi, Elad N.
    Drexel University, PA 19104 USA; Nucl Research Centre Negev, Israel.
    May, Steven J.
    Drexel University, PA 19104 USA.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Barsoum, Michel W.
    Drexel University, PA 19104 USA.
    Experimental and theoretical characterization of ordered MAX phases Mo2TiAlC2 and Mo2Ti2AlC32015In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 118, no 9, p. 094304-Article in journal (Refereed)
    Abstract [en]

    Herein, we report on the phase stabilities and crystal structures of two newly discovered ordered, quaternary MAX phases-Mo2TiAlC2 and Mo2Ti2AlC3-synthesized by mixing and heating different elemental powder mixtures of mMo:(3-m) Ti:1.1Al:2C with 1.5 less than= m less than= 2.2 and 2Mo: 2Ti:1.1Al:2.7C to 1600 degrees C for 4 h under Ar flow. In general, for m greater than= 2 an ordered 312 phase, (Mo2Ti) AlC2, was the majority phase; for mless than 2, an ordered 413 phase (Mo2Ti2)AlC3, was the major product. The actual chemistries determined from X-ray photoelectron spectroscopy (XPS) are Mo2TiAlC1.7 and Mo2Ti1.9Al0.9C2.5, respectively. High resolution scanning transmission microscopy, XPS and Rietveld analysis of powder X-ray diffraction confirmed the general ordered stacking sequence to be Mo-Ti-Mo-Al-Mo-Ti-Mo for Mo2TiAlC2 and Mo-Ti-Ti-Mo-Al-Mo-Ti-Ti-Mo for Mo2Ti2AlC3, with the carbon atoms occupying the octahedral sites between the transition metal layers. Consistent with the experimental results, the theoretical calculations clearly show that M layer ordering is mostly driven by the high penalty paid in energy by having the Mo atoms surrounded by C in a face-centered configuration, i.e., in the center of the Mn+1Xn blocks. At 331 GPa and 367 GPa, respectively, the Youngs moduli of the ordered Mo2TiAlC2 and Mo2Ti2AlC3 are predicted to be higher than those calculated for their ternary end members. Like most other MAX phases, because of the high density of states at the Fermi level, the resistivity measurement over 300 to 10K for both phases showed metallic behavior. (C) 2015 AIP Publishing LLC.

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  • 11.
    Azina, Clio
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Rhein Westfal TH Aachen, Germany.
    Mraz, Stanislav
    Rhein Westfal TH Aachen, Germany.
    Greczynski, Grzegorz
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hans, Marcus
    Rhein Westfal TH Aachen, Germany.
    Primetzhofer, Daniel
    Uppsala Univ, Sweden.
    Schneider, Jochen M.
    Rhein Westfal TH Aachen, Germany.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Oxidation behaviour of V2AlC MAX phase coatings2020In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 40, no 13, p. 4436-4444Article in journal (Refereed)
    Abstract [en]

    We report on the oxidation behaviour of V2AlC coatings up to 800 degrees C, in air. The coatings were deposited at 580 degrees C using magnetron sputtering from a powder metallurgical composite V2AlC target and were subsequently oxidised for 5, 15 and 30 min. The microstructural evolution of the samples was investigated, and X-ray diffraction patterns were collected to track the formation of oxides. The first indications of oxidation appear after just 15 min at 500 degrees C, as V-based oxides grew on the surface of the coatings. Later, the presence of mostly V-based oxides and ternary (V, Al)-oxides was observed starting after 5 min at 600 degrees C. Further analyses confirmed outward diffusion of V and inward diffusion of O, while Al tends to sublimate. alpha-A12O3 was only indexed after 5 min at 800 degrees C. Ex-situ electrical resistivity measurements allowed tracking the oxidation progress of the V2AlC coating.

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  • 12.
    Azina, Clio
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Tunca, Bensu
    Katholieke Univ Leuven, Belgium.
    Petruhins, Andrejs
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Xin, Binbin
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Yildizhan Özyar, Melike
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Persson, Per O A
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Vleugels, Jozef
    Katholieke Univ Leuven, Belgium.
    Lambrinou, Konstantina
    SCK CEN, Belgium; Univ Huddersfield, England.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Deposition of MAX phase-containing thin films from a (Ti,Zr)(2)AlC compound target2021In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 551, article id 149370Article in journal (Refereed)
    Abstract [en]

    This work reports on sputter depositions carried out from a compound (Ti,Zr)(2)AlC target on Al2O3(0 0 0 1) substrates at temperatures ranging between 500 and 900 degrees C. Short deposition times yielded 30-40 nm-thick Al-containing (Ti,Zr)C films, whereas longer depositions yielded thicker films up to 90 nm which contained (Ti,Zr)C and intermetallics. At 900 degrees C, the longer depositions led to films that also consisted of solid solution MAX phases. Detailed transmission electron microscopy showed that both (Ti,Zr)(2)AlC and (Ti,Zr)(3)AlC2 solid solution MAX phases were formed. Moreover, this work discusses the growth mechanism of the thicker films, which started with the formation of the mixed (Ti,Zr)C carbide, followed by the nucleation and growth of aluminides, eventually leading to solid state diffusion of Al within the carbide, at the highest temperature (900 degrees C) to form the MAX phases.

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  • 13.
    Buchholt, Kristina
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied 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.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Ghandi, R
    Royal Institute Technology, KTH.
    Domeij, M
    Royal Institute Technology, KTH.
    Zetterling, C M
    Royal Institute Technology, KTH.
    Behan, G
    Trinity College Dublin.
    Zhang, H
    Trinity College Dublin.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied 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.
    Growth and characterization of epitaxial Ti3GeC2 thin films on 4H-SiC(0001)2012In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 343, no 1, p. 133-137Article in journal (Refereed)
    Abstract [en]

    Epitaxial Ti3GeC2 thin films were deposited on 4 degrees off-cut 4H-SiC(0001) using magnetron sputtering from high purity Ti, C, and Ge targets. Scanning electron microscopy and helium ion microscopy show that the Ti3GeC2 films grow by lateral step-flow with {11 (2) over bar0} faceting on the SiC surface. Using elastic recoil detection analysis, atomic force microscopy, and X-Ray diffraction the films were found to be substoichiometric in Ge with the presence of small Ge particles at the surface of the film.

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  • 14.
    Buchholt, Kristina
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied 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.
    Lu, Jun
    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 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.
    Step-flow growth of nanolaminate Ti3SiC2 epitaxial layers on 4H-SiC(0 0 0 1)2011In: SCRIPTA MATERIALIA, ISSN 1359-6462, Vol. 64, no 12, p. 1141-1144Article in journal (Refereed)
    Abstract [en]

    Epitaxial Ti3SiC2(0 0 0 1) films were deposited on 4 degrees off-cut 4H-SiC(0 0 0 1) wafers using magnetron sputtering. A lateral step-flow growth mechanism of the Ti3SiC2 was discovered by X-ray diffraction, elastic recoil detection analysis, atomic force microscopy and electron microscopy. Helium ion microscopy revealed contrast variations on the Ti3SiC2 terraces, suggesting a mixed Si and Ti(C) termination. Si-rich growth conditions results in Ti3SiC2 layers with pronounced {1 1 (2) over bar 0) faceting and off-oriented TiSi2 crystallites, while stoichiometric growth yields truncated {1 (1) over bar 0 0) terrace edges.

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  • 15.
    Buchholt, Kristina
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Ghandi, R
    Royal Institute of Technology.
    Domeij, M
    Royal Institute of Technology.
    Zetterling, C-M
    Royal Institute of Technology.
    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.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Ohmic contact properties of magnetron sputtered Ti3SiC2 on n- and p-type 4H-silicon carbide2011In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 98, no 4, p. 042108-Article in journal (Refereed)
    Abstract [en]

    Epitaxial Ti3SiC2 (0001) thin film contacts were grown on doped 4H-SiC (0001) using magnetron sputtering in an ultra high vacuum system. The specific contact resistance was investigated using linear transmission line measurements. Rapid thermal annealing at 950 degrees C for 1 min of as-deposited films yielded ohmic contacts to n-type SiC with contact resistances in the order of 10(-4) Omega cm(2). Transmission electron microscopy shows that the interface between Ti3SiC2 and n-type SiC is atomically sharp with evidence of interfacial ordering after annealing.

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    ApplPhysLett
  • 16.
    Bugnet, M
    et al.
    University of Poitiers, France .
    Mauchamp, V
    University of Poitiers, France .
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Jaouen, M
    University of Poitiers, France .
    Cabioch, T
    University of Poitiers, France .
    Contribution of core-loss fine structures to the characterization of ion irradiation damages in the nanolaminated ceramic Ti3AlC22013In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 61, no 19, p. 7348-7363Article in journal (Refereed)
    Abstract [en]

    The effect of low-energy ion irradiation on the nanolaminated Ti3AlC2 is investigated by means of X-ray diffraction, transmission electron microscopy, electron energy loss and X-ray absorption spectroscopy. The chemical sensitivity and local order probing from core-loss edges provide new insights into the structural modifications induced under irradiation. From the analysis of the C K energy loss near-edge structure and Al K X-ray absorption near-edge structure by ab initio calculations, the influence of the layered structure of this compound on the irradiation damage is demonstrated, and damage is found to be preferentially localized in the aluminum planes of the structure. On the basis of comparisons between calculations and experimental spectra, a structural model is proposed for the irradiated state. This study emphasizes the utility of core-loss fine structure analysis to enhance understanding of ion irradiation-induced damage in complex crystalline materials.

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  • 17.
    Burcea, Razvan
    et al.
    Univ Poitiers, France.
    Barbot, Jean-Francois
    Univ Poitiers, France.
    Renault, Pierre-Olivier
    Univ Poitiers, France.
    Eyidi, Dominique
    Univ Poitiers, France.
    Girardeau, Thierry
    Univ Poitiers, France.
    Marteau, Marc
    Univ Poitiers, France.
    Giovannelli, Fabien
    Univ Tours, France.
    Zenji, Ahmad
    Univ Bordeaux, France.
    Rampnoux, Jean-Michel
    Univ Bordeaux, France.
    Dilhaire, Stefan
    Univ Bordeaux, France.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    le Febvrier, Arnaud
    Univ Poitiers, France.
    Correction: Influence of Generated Defects by Ar Implantation on the Thermoelectric Properties of ScN (vol 5, pg 11025, 2022)2023In: ACS Applied Energy Materials, E-ISSN 2574-0962Article in journal (Other academic)
  • 18.
    Burcea, Razvan
    et al.
    Univ Poitiers ENSMA, France.
    Barbot, Jean-Francois
    Univ Poitiers ENSMA, France.
    Renault, Pierre-Olivier
    Univ Poitiers ENSMA, France.
    Eyidi, Dominique
    Univ Poitiers ENSMA, France.
    Girardeau, Thierry
    Univ Poitiers ENSMA, France.
    Marteau, Marc
    Univ Poitiers ENSMA, France.
    Giovannelli, Fabien
    Univ Tours, France.
    Zenji, Ahmad
    Univ Bordeaux, France.
    Rampnoux, Jean-Michel
    Univ Bordeaux, France.
    Dilhaire, Stefan
    Univ Bordeaux, France.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Le Febvrier, Arnaud
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Influence of Generated Defects by Ar Implantation on the Thermoelectric Properties of ScN2022In: ACS Applied Energy Materials, E-ISSN 2574-0962, Vol. 5, no 9, p. 11025-11033Article in journal (Refereed)
    Abstract [en]

    Nowadays, making thermoelectric materials more efficient in energy conversion is still a challenge. In this work, to reduce the thermal conductivity and thus improve the overall thermoelectric performances, point and extended defects were generated in epitaxial 111-ScN thin films by implantation using argon ions. The films were investigated by structural, optical, electrical, and thermoelectric characterization methods. The results demonstrated that argon implantation leads to the formation of stable defects (up to 750 K operating temperature). These were identified as interstitial-type defect dusters and argon vacancy complexes. The insertion of these specific defects induces acceptor-type deep levels in the band gap, yielding a reduction in the free-carrier mobility. With a reduced electrical conductivity, the irradiated sample exhibited a higher Seebeck coefficient while maintaining the power factor of the film. The thermal conductivity is strongly reduced from 12 to 3 W.m(-1). K-1 at 300 K, showing the influence of defects in increasing phonon scattering. Subsequent high-temperature annealing at 1573 K leads to the progressive evolution of these defects: the initial dusters of interstitials evolved to the benefit of smaller dusters and the formation of bubbles. Thus, the number of free carriers, the resistivity, and the Seebeck coefficient are almost restored but the mobility of the carriers remains low and a 30% drop in thermal conductivity is still effective (k(total) similar to 8.5 Wm(-1).K-1). This study shows that control defect engineering with defects introduced by irradiation using noble gases in a thermoelectric coating can be an attractive method to enhance the figure of merit of thermoelectric materials.

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  • 19.
    Burcea, Razvan
    et al.
    Univ Poitiers, France.
    Bouteiller, Hugo
    Univ Poitiers, France.
    Hurand, Simon
    Univ Poitiers, France.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Barbot, Jean-Francois
    Univ Poitiers, France.
    Le Febvrier, Arnaud
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Effect of induced defects on conduction mechanisms of noble-gas-implanted ScN thin films2023In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 134, no 5, article id 055107Article in journal (Refereed)
    Abstract [en]

    Noble-gas implantation was used to introduce defects in n-type degenerate ScN thin films to tailor their transport properties. The electrical resistivity increased significantly with the damage levels created, while the electron mobility decreased regardless of the nature of the ion implanted and their doses. However, the transport property characterizations showed that two types of defects were formed during implantation, named point-like and complex-like defects depending on their temperature stability. The point-like defects changed the electrical conduction mode from metallic-like to semiconducting behavior. In the low temperature range, where both groups of defects were present, the dominant operative conduction mechanism was the variable range hopping conduction mode. Beyond a temperature of about 400 K, the point-like defects started to recover with an activation energy of 90 meV resulting in a decrease in resistivity, independent of the incident ion. The complex-like defects were, therefore, the only remaining group of defects after annealing above 700 K. These latter, thermally stable at least up to 750 K, introduced deep acceptor levels in the bandgap resulting in an increase in the electrical resistivity with higher carrier scattering while keeping the metallic-like behavior of the sample. The generation of both types of defects, as determined by resistivity measurements, appeared to occur through a similar mechanism within a single collision cascade.

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  • 20.
    Cabioch, Thierry
    et al.
    University of Poitiers, France.
    Alkazaz, Malaz
    University of Poitiers, France.
    Beaufort, Marie-France
    University of Poitiers, France.
    Nicolai, Julien
    University of Poitiers, France.
    Eyidi, Dominique
    University of Poitiers, France.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. University of Poitiers, France.
    Ti2AlN thin films synthesized by annealing of (Ti plus Al)/AlN multilayers2016In: Materials research bulletin, ISSN 0025-5408, E-ISSN 1873-4227, Vol. 80, p. 58-63Article in journal (Refereed)
    Abstract [en]

    Single-phase Ti2AlN thin films were obtained by annealing in vacuum of (Ti + Al)/AIN multilayers deposited at room temperature by magnetron sputtering onto single-crystalline (0001) 4H-SiC and (0001) Al2O3 substrates. In-situ X-ray diffraction experiments combined with ex-situ cross-sectional transmission electron microscopy observations reveal that interdiffusion processes occur in the multilayer at a temperature of similar to 400 degrees C leading to the formation of a (Ti, Al, N) solid solution, having the hexagonal structure of alpha-Ti, whereas the formation of Ti2AlN occurs at 550-600 degrees C. Highly oriented (0002) Ti2AlN thin films can be obtained after an annealing at 750 degrees C. (C) 2016 Elsevier Ltd. All rights reserved.

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  • 21.
    Cabioch, Thierry
    et al.
    University of Poitiers.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Mauchamp, Vincent
    University of Poitiers.
    Jaouen, Michel
    University of Poitiers.
    Structural investigation of substoichiometry and solid solution effects in Ti2Al(C-x,N1-x)(y) compounds2012In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 32, no 8, p. 1803-1811Article in journal (Refereed)
    Abstract [en]

    The milling, cold compaction and thermal annealing (4 h-1400 degrees C-Ar flow) of Ti, TiC, Al and AlN powders were used to produce Ti2Al(CxN(1-x))(y) compounds with x = 0, 0.25, 0.5, 0.75, 1 and 0.7 andlt;= y andlt;= 1. X-ray diffraction analysis, scanning electron microscopy observations combined with microanalysis confirmed the formation of the almost pure Ti(2)A/CxN(1-x) carbonitrides for y=1 whereas increasing amounts of titanium aluminides were formed when y decreases. Proportions of the different phases deduced from Rietveld refinements of the X-ray diffractograms indicate that no or very poor substoichiometry in carbon was possible in carbide whereas C and N deficiency can be achieved in nitrides and carbonitrides Ti2AlCxN(1-x). Electron Energy Loss Spectroscopy investigations confirm that carbonitrides can have at least 20% of vacancies on the C or N site. The a lattice parameter varies linearly with x whereas it is not the case for the c lattice parameter, its values being lower for the carbonitrides. Furthermore, a strong broadening of the carbonitrides XRD peaks is observed, a phenomenon that can be mainly attributed to C and N concentration gradients inside the samples.

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  • 22.
    Cabioch, Thierry
    et al.
    Université de Poitiers, France.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Mauchamp, Vincent
    Université de Poitiers, France.
    Jaouen, Michel
    Université de Poitiers, France.
    Barsoum, Michel W.
    Université de Poitiers, France and Drexel University, Philadelphia, USA.
    Tailoring of the thermal expansion of Cr2(Alx,Ge1−x)C phases2013In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 33, no 4, p. 897-904Article in journal (Refereed)
    Abstract [en]

    We report thermal expansion coefficients of the end members and solid-solution compounds in the Cr2(Alx,Ge1−x)C system. All samples studied were essentially phase-pure Cr2AlxGe1−xC except the Cr2GeC sample, which contained a substantial fraction of Cr5Ge3Cx. X-ray diffraction performed in the 25–800 °C temperature range shows that the in-plane thermal expansion remains essentially constant at about 14 ± 1 × 10−6 K−1 irrespective of Al content. The thermal expansion of the c axis decreases monotonically from 17 ± 1 × 10−6 K−1 for Cr2GeC to ∼12 ± 1 × 10−6 K−1 with increasing Al content. At around the Cr2(Al0.75,Ge0.25)C composition, the thermal expansion coefficients along the two directions are equal; a useful property to minimize thermal residual stresses. This study thus demonstrates that a solid-solution approach is a route for tuning a physical property like the thermal expansion. For completeness, we also include a structure description of the Cr5Ge3Cx phase, which has been reported before but is not well documented. Its space group is P63/mcm and its a and c lattice parameters are 7.14 Å and 4.88 Å, respectively. We also measured the thermal expansion coefficients of the Cr5Ge3Cx phase. They are found to be 16.3 × 10−6 K−1 and 28.4 × 10−6 K−1 along the a and c axes, respectively. Thus, the thermal expansion coefficients of Cr5Ge3Cx are highly anisotropic and considerably larger than those of the Cr2(Alx,Ge1−x)C phases.

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  • 23.
    Calamba, Katherine
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. Univ Lorraine, France.
    Pierson, J. F.
    Univ Lorraine, France.
    Bruyere, S.
    Univ Lorraine, France.
    Le Febvrier, Arnaud
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Barrirero, Jenifer
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. Saarland Univ, Germany.
    Muecklich, F.
    Saarland Univ, Germany.
    Boyd, Robert
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    Jöesaar Johansson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. SECO Tools AB, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Dislocation structure and microstrain evolution during spinodal decomposition of reactive magnetron sputtered heteroepixatial c-(Ti-0.37,Al-0.63)N/c-TiN films grown on MgO(001) and (111) substrates2019In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 125, no 10, article id 105301Article in journal (Refereed)
    Abstract [en]

    Heteroepitaxial c-(Ti-0.37,Al-0.63)N thin films were grown on MgO(001) and MgO(111) substrates using reactive magnetron sputtering. High resolution high-angle annular dark-field scanning transmission electron micrographs show coherency between the film and the substrate. In the as-deposited state, x-ray diffraction reciprocal space maps show a strained epitaxial film. Corresponding geometric phase analysis (GPA) deformation maps show a high stress in the film. At elevated temperature (900 degrees C), the films decompose to form iso-structural coherent c-Al- and c-TiN-rich domains, elongated along the elastically soft amp;lt;100amp;gt; directions. GPA analysis reveals that the c-TiN domains accommodate more dislocations than the c-AlN domains. This is because of the stronger directionality of the covalent bonds in c-AlN compared with c-TiN, making it more favorable for the dislocations to accumulate in c-TiN. The defect structure and strain generation in c-(Ti,Al)N during spinodal decomposition is affected by the chemical bonding state and elastic properties of the segregated domains.

  • 24.
    Charalampopoulou, Evangelia
    et al.
    SCK CEN, Belgium; Univ Antwerp, Belgium.
    Lambrinou, Konstantina
    SCK CEN, Belgium; Univ Huddersfield, England.
    Van der Donck, Tom
    Katholieke Univ Leuven, Belgium.
    Paladino, Boris
    Ist Italiano Tecnol, Italy.
    Di Fonzo, Fabio
    Ist Italiano Tecnol, Italy.
    Azina, Clio
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Mraz, Stanislav
    Rhein Westfal TH Aachen, Germany.
    Schneider, Jochen M.
    Rhein Westfal TH Aachen, Germany.
    Schryvers, Dominique
    Univ Antwerp, Belgium.
    Delville, Remi
    SCK CEN, Belgium.
    Early stages of dissolution corrosion in 316L and DIN 1.4970 austenitic stainless steels with and without anticorrosion coatings in static liquid lead-bismuth eutectic (LBE) at 500 degrees C2021In: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 178, article id 111234Article in journal (Refereed)
    Abstract [en]

    This work addresses the early stages (<= 1000 h) of the dissolution corrosion behavior of 316L and DIN 1.4970 austenitic stainless steels in contact with oxygen-poor (C-O < 10(-8) mass%), static liquid lead-bismuth eutectic (LBE) at 500 degrees C for 600-1000 h. The objective of this study was to determine the relative early-stage resistance of the uncoated steels to dissolution corrosion and to assess the protectiveness of select candidate coatings (Cr2AlC, Al2O3, V2AlxCy). The simultaneous exposure of steels with intended differences in microstructure and thermomechanical state showed the effects of steel grain size, density of annealing/deformation twins, and secondary precipitates on the steel dissolution corrosion behavior. The findings of this study provide recommendations on steel manufacturing with the aim of using the steels to construct Gen-IV lead-cooled fast reactors.

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  • 25.
    Chowdhury, Susmita
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hjort, Victor
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Shu, Rui
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Greczynski, Grzegorz
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Le Febvrier, Arnaud
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Magnuson, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Thermoelectric properties and electronic structure of Cr(Mo,V)Nx thin films studied by synchrotron and lab-based x-ray spectroscopy2023In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 108, no 20, article id 205134Article in journal (Refereed)
    Abstract [en]

    Chromium-based nitrides are used in hard, resilient coatings and show promise for thermoelectric applications due to their combination of structural, thermal, and electronic properties. Here, we investigate the electronic structures and chemical bonding correlated to the thermoelectric properties of epitaxially grown chromium-based multicomponent nitride Cr(Mo,V)Nx thin films. The small amount of N vacancies causes Cr 3d and N 2p states to appear at the Fermi level and reduces the band gap in Cr0.51N0.49. Incorporating holes by alloying of V in N-deficient CrN results in an enhanced thermoelectric power factor with marginal change in the charge transfer of Cr to N compared with Cr0.51N0.49. Further alloying of Mo, isoelectronic to Cr, increases the density of states at the Fermi level due to hybridization of the (Cr, V) 3d and Mo 4d-N 2p states in Cr(Mo,V)Nx. This hybridization and N off-stoichiometry result in more metal-like electrical resistivity and reduction in Seebeck coefficient. The N deficiency in Cr(Mo,V)Nx also depicts a critical role in reduction of the charge transfer from metal to N site compared with Cr0.51N0.49 and Cr0.50V0.03N0.47. In this paper, we envisage ways for enhancing thermoelectric properties through electronic band engineering by alloying and competing effects of N vacancies.

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  • 26.
    Ding, Haoming
    et al.
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China; CNiTECH, Peoples R China.
    Li, Youbing
    Chinese Acad Sci, Peoples R China; CNiTECH, Peoples R China.
    Li, Mian
    Chinese Acad Sci, Peoples R China; CNiTECH, Peoples R China.
    Chen, Ke
    Chinese Acad Sci, Peoples R China; CNiTECH, Peoples R China.
    Liang, Kun
    Chinese Acad Sci, Peoples R China; CNiTECH, Peoples R China.
    Chen, Guoxin
    Chinese Acad Sci, Peoples R China; CNiTECH, Peoples R China.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Palisaitis, Justinas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Persson, Per O A
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Du, Shiyu
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China; CNiTECH, Peoples R China.
    Chai, Zhifang
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China; CNiTECH, Peoples R China.
    Gogotsi, Yury
    Drexel Univ, PA 19104 USA.
    Huang, Qing
    Chinese Acad Sci, Peoples R China; CNiTECH, Peoples R China; Adv Energy Sci & Technol Guangdong Lab, Peoples R China.
    Chemical scissor-mediated structural editing of layered transition metal carbides2023In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 379, no 6637, p. 1130-1135Article in journal (Refereed)
    Abstract [en]

    Intercalated layered materials offer distinctive properties and serve as precursors for important two-dimensional (2D) materials. However, intercalation of non-van der Waals structures, which can expand the family of 2D materials, is difficult. We report a structural editing protocol for layered carbides (MAX phases) and their 2D derivatives (MXenes). Gap-opening and species-intercalating stages were respectively mediated by chemical scissors and intercalants, which created a large family of MAX phases with unconventional elements and structures, as well as MXenes with versatile terminals. The removal of terminals in MXenes with metal scissors and then the stitching of 2D carbide nanosheets with atom intercalation leads to the reconstruction of MAX phases and a family of metal-intercalated 2D carbides, both of which may drive advances in fields ranging from energy to printed electronics.

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  • 27.
    Ding, Haoming
    et al.
    State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an, People’s Republic of China; bEngineering Laboratory of Advanced Energy Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, People’s Republic of China.
    Li, Youbing
    Engineering Laboratory of Advanced Energy Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, People’s Republic of China; University of Chinese Academy of Sciences, Beijing, People’s Republic of China.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Luo, Kan
    Engineering Laboratory of Advanced Energy Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, People’s Republic of China.
    Chen, Ke
    Engineering Laboratory of Advanced Energy Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, People’s Republic of China.
    Li, Mian
    Engineering Laboratory of Advanced Energy Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, People’s Republic of China.
    Persson, Per O. Å.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Du, Shiyu
    Engineering Laboratory of Advanced Energy Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, People’s Republic of China.
    Huang, Zhengren
    Engineering Laboratory of Advanced Energy Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, People’s Republic of China.
    Chai, Zhifang
    Engineering Laboratory of Advanced Energy Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, People’s Republic of China.
    Wang, Hongjie
    State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an, People’s Republic of China.
    Huang, Ping
    aState Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an, People’s Republic of China.
    Huang, Qing
    Engineering Laboratory of Advanced Energy Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, People’s Republic of China.
    Synthesis of MAX phases Nb2CuC and Ti2(Al0.1Cu0.9)N by A-site replacement reaction in molten salts2019In: Materials Research Letters, E-ISSN 2166-3831, Vol. 7, no 12, p. 510-516Article in journal (Refereed)
    Abstract [en]

    New MAX phases Ti2(AlxCu1−x)N and Nb2CuC were synthesized by A-site replacement by reacting Ti2AlN and Nb2AlC, respectively, with CuCl2 or CuI molten salt. X-ray diffraction, scanning electron microscopy, and atomically resolved scanning transmission electron microscopy showed complete A-site replacement in Nb2AlC, which lead to the formation of Nb2CuC. However, the replacement of Al in Ti2AlN phase was only close to complete at Ti2(Al0.1Cu0.9)N. Density-functional theory calculations corroborated the structural stability of Nb2CuC and Ti2CuN phases. Moreover, the calculated cleavage energy in these Cu-containing MAX phases are weaker than in their Al-containing counterparts.

    The preparation of MAX phases Nb2CuC and Ti2(Al0.1Cu0.9)N were realized by A-site replacement in Ti2AlN and Nb2AlN, respectively.

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  • 28.
    Du, Hao
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering. Guizhou Univ, Peoples R China; Guizhou Univ, Peoples R China.
    Shu, Rui
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Boyd, Robert
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    Le Febvrier, Arnaud
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Helmersson, Ulf
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Lundin, Daniel
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    Evolution of microstructure and properties of TiNbCrAlHfN films grown by unipolar and bipolar high-power impulse magnetron co-sputtering: The role of growth temperature and ion bombardment2023In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 459, article id 129389Article in journal (Refereed)
    Abstract [en]

    Growth temperature (Ts) and ion irradiation energy (Ei) are important factors that influence film growth as well as their properties. In this study, we investigate the evolution of crystal structure and residual stress of TiNb-CrAlHfN films under various Ts and Ei conditions, where the latter is mainly controlled by tuning the flux of sputtered Hf ions using bipolar high-power impulse magnetron (BP-HiPIMS). The results show that TiNbCrAlHfN films exhibit the typical FCC NaCl-type structure. By increasing Ts from room temperature to 600 degrees C, the film texture changes from high-surface-energy (111) to low-surface-energy (100) accompanied by a higher crystal-linity in the out-of-plane direction and a more disordered growth tilt angle to the surface plane. In addition, compressive stress decreases with increasing Ts, which is ascribed to changes in the film growth both in the early and post-coalescence stages and more tensile thermal stress at elevated Ts. In contrast, a clear texture transition window is seen under various Ei of Hf+ ions, i.e., high-surface-energy planes change to low-surface-energy planes as Ei exceeds-110 eV, while low-surface-energy planes gradually transform back to high-surface-energy planes when Ei increases from 210 to 260 eV, indicating renucleation events for Ei > 210 eV. Compressive stress in-creases with increasing Ei but is still lower than that of a reference series with DC substrate bias UDC =-100 V. The study shows that it is possible to tailor properties of FCC-structured high-entropy nitrides by varying Ts and Ei in a similar fashion to conventional transition metal nitrides using the approach of unipolar and bipolar HiPIMS co-sputtering.

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  • 29.
    Du, Hao
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering. Guizhou Univ, Peoples R China; Guizhou Univ, Peoples R China.
    Shu, Rui
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Boyd, Robert
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    Le Febvrier, Arnaud
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Sortica, Mauricio A.
    Uppsala Univ, Sweden.
    Primetzhofer, Daniel
    Uppsala Univ, Sweden; Uppsala Univ, Sweden.
    Helmersson, Ulf
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Lundin, Daniel
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    Corundum-structured AlCrNbTi oxide film grown using high-energy early-arriving ion irradiation in high-power impulse magnetron sputtering2023In: Scripta Materialia, ISSN 1359-6462, E-ISSN 1872-8456, Vol. 234, article id 115578Article in journal (Refereed)
    Abstract [en]

    Multicomponent or high-entropy oxide films are of interest due to their remarkable structure and properties. Here, energetic ion irradiation is utilized for controlling the phase formation and structure of AlCrNbTi oxide at growth temperature of 500 degrees C. The ion acceleration is achieved by using a high-power impulse magnetron sputtering (HiPIMS) discharge, accompanied by a 10 & mu;s-long synchronized substrate bias (Usync), to minimize the surface charging effect and accelerate early-arriving ions, mainly Al+, O+, Ar2+, and Al2+. By increasing the magnitude of Usync from-100 V to-500 V, the film structure changes from amorphous to single-phase corundum, followed by the formation of high-number-density stacking faults (or nanotwins) at Usync =-500 V. This approach paves the way to tailor the high-temperature-phase and defect formation of oxide films at low growth temperature, with prospects for use in protective-coating and dielectric applications.

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  • 30.
    Du, Yong
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Shanghai Inst Technol, Peoples R China.
    Chen, Jiageng
    Shanghai Inst Technol, Peoples R China.
    Liu, Xin
    Shanghai Inst Technol, Peoples R China.
    Lu, Chun
    Shenyang Aerosp Univ, Peoples R China.
    Xu, Jiayue
    Shanghai Inst Technol, Peoples R China.
    Paul, Biplab
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Flexible n-Type Tungsten Carbide/Polylactic Acid Thermoelectric Composites Fabricated by Additive Manufacturing2018In: Coatings, ISSN 2079-6412, Vol. 8, no 1, article id 25Article in journal (Refereed)
    Abstract [en]

    Flexible n-type tungsten carbide/polylactic acid (WC/PLA) composites were fabricated by additive manufacturing and their thermoelectric properties were investigated. The preparation of an n-type polymer-based thermoelectric composite with good stability in air atmosphere via additive manufacturing holds promise for application in flexible thermoelectric devices. For WC/PLA volume ratios varying from similar to 33% to 60%, the electrical conductivity of the composites increased from 10.6 to 42.2 S/cm, while the Seebeck coefficients were in the range -11 to -12.3 V/K. The thermal conductivities of the composites varied from similar to 0.2 to similar to 0.28 Wamp;lt;boldamp;gt;mamp;lt;/boldamp;gt;-1amp;lt;boldamp;gt;Kamp;lt;/boldamp;gt;-1 at similar to 300 K.

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  • 31.
    Du, Yong
    et al.
    Shanghai Inst Technol, Peoples R China.
    Chen, Jiageng
    Shanghai Inst Technol, Peoples R China.
    Meng, Qiufeng
    Shanghai Inst Technol, Peoples R China.
    Xu, Jiayue
    Shanghai Inst Technol, Peoples R China.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Paul, Biplab
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Flexible Thermoelectric Double-Layer Inorganic/Organic Composites Synthesized by Additive Manufacturing2020In: Advanced Electronic Materials, E-ISSN 2199-160X, Vol. 6, no 8, article id 2000214Article in journal (Refereed)
    Abstract [en]

    This study shows an approach to combine a high electrical conductivity of one composite layer with a high Seebeck coefficient of another composite layer in a double-layer composite, resulting in high thermoelectric power factor. Flexible double-layer-composites, made from Bi2Te3-based-alloy/polylactic acid (BTBA/PLA) composites and Ag/PLA composites, are synthesized by solution additive manufacturing. With the increase in Ag volume-ratio from 26.3% to 41.7% in Ag/PLA layers, the conductivity of the double-layer composites increases from 12 S cm(-1)to 1170 S cm(-1), while the Seebeck coefficient remains approximate to 80 mu V K(-1)at 300 K. With further increase in volume ratio of Ag until 45.6% in Ag/PLA composite layer, the electrical conductivity of the double-layer composites increases to 1710 S cm(-1), however, with a slight decrease of the Seebeck coefficient to 64 mu V K-1. The electrical conductivity and Seebeck coefficient vary only to a limited extent with the temperature. The high Seebeck coefficient is due to scattering of low energy charge carriers across compositionally graded interfaces. A power factor of 875 mu W m(-1) K(-2)is achieved at 360 K for 41.7 vol.% Ag in the Ag/PLA layers. Solution additive manufacturing can directly print this double-layer composite into intricate geometries, making this process is promising for large-scale fabrication of thermoelectric composites.

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  • 32.
    Du, Yong
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Shanghai Inst Technol, Peoples R China.
    Chen, Jiageng
    Shanghai Inst Technol, Peoples R China.
    Meng, Qiufeng
    Shanghai Inst Technol, Peoples R China.
    Xu, Jiayue
    Shanghai Inst Technol, Peoples R China.
    Paul, Biplab
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Flexible ternary carbon black/Bi2Te3 based alloy/polylactic acid thermoelectric composites fabricated by additive manufacturing2020In: Journal of Materiomics, ISSN 2352-8478, E-ISSN 2352-8486, Vol. 6, no 2, p. 293-299Article in journal (Refereed)
    Abstract [en]

    Flexible ternary carbon black/Bi2Te3 based alloy/polylactic acid (CB/BTBA/PLA) composites were fabricated by additive manufacturing and their thermoelectric properties were investigated from 300 K to 360 K. At 300 K, as the mass ratios of BTBAs in the composites increased from 38.5% to 71.4%, both the electrical conductivity and Seebeck coefficient of the composites increased from 5.8 S/cm to 13.3 S/cm, and from 60.2 mV/K to 119.9 mV/K, respectively, and the thermal conductivity slightly increased from 0.15 W m(-1)K(-1) to 0.25 W m(-1)K(-1), as a result, the ZT value of the composites increased from 0.004 to 0.023. As the temperature increased from 300 K to 360 K, the electrical conductivity of all the composites slightly decreased, while the thermal conductivity slowly increased, and a highest ZT value of 0.024 was achieved for the composites with 71.4% BTBAs at 320 K. Unlike traditional sterolithography, fused deposition modeling, selective laser melting, etc., this additive manufacturing process can directly print the solutions which contain inorganic fillers and polymer matrixes into almost any designed intricate geometries of thermoelectric composites, therefore this process has great potential to be used for fabrication of flexible polymer based thermoelectric composites and devices. (C) 2020 The Chinese Ceramic Society. Production and hosting by Elsevier B.V.

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  • 33.
    Du, Yong
    et al.
    Shanghai Inst Technol, Peoples R China.
    Li, Haixia
    Shanghai Inst Technol, Peoples R China.
    Jia, Xuechen
    Shanghai Inst Technol, Peoples R China.
    Dou, Yunchen
    Shanghai Inst Technol, Peoples R China.
    Xu, Jiayue
    Shanghai Inst Technol, Peoples R China.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Preparation and Thermoelectric Properties of Graphite/poly(3,4-ethyenedioxythiophene) Nanocomposites2018In: Energies, E-ISSN 1996-1073, Vol. 11, no 10, article id 2849Article in journal (Refereed)
    Abstract [en]

    Graphite/poly(3,4-ethyenedioxythiophene) (PEDOT) nanocomposites were prepared by an in-situ oxidative polymerization process. The electrical conductivity and Seebeck coefficient of the graphite/PEDOT nanocomposites with different content of graphite were measured in the temperature range from 300 K to 380 K. The results show that as the content of graphite increased from 0 to 37.2 wt %, the electrical conductivity of the nanocomposites increased sharply from 3.6 S/cm to 80.1 S/cm, while the Seebeck coefficient kept almost the same value (in the range between 12.0 V/K to 15.1 V/K) at 300 K, which lead to an increased power factor. The Seebeck coefficient of the nanocomposites increased from 300 K to 380 K, while the electrical conductivity did not substantially depend on the measurement temperature. As a result, a power factor of 3.2 Wm(-1) K-2 at 380 K was obtained for the nanocomposites with 37.2 wt % graphite.

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  • 34.
    Du, Yong
    et al.
    Shanghai Inst Technol, Peoples R China.
    Li, Jia
    Shanghai Inst Technol, Peoples R China.
    Xu, Jiayue
    Shanghai Inst Technol, Peoples R China.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Thermoelectric Properties of Reduced Graphene Oxide/Bi2Te3 Nanocomposites2019In: Energies, E-ISSN 1996-1073, Vol. 12, no 12, article id 2430Article in journal (Refereed)
    Abstract [en]

    Reduced graphene oxide (rGO)/Bi2Te3 nanocomposite powders with different contents of rGO have been synthesized by a one-step in-situ reductive method. Then, rGO/Bi2Te3 nanocomposite bulk materials were fabricated by a hot-pressing process. The effect of rGO contents on the composition, microstructure, TE properties, and carrier transportation of the nanocomposite bulk materials has been investigated. All the composite bulk materials show negative Seebeck coefficient, indicating n-type conduction. The electrical conductivity for all the rGO/Bi2Te3 nanocomposite bulk materials decreased with increasing measurement temperature from 25 degrees C to 300 degrees C, while the absolute value of Seebeck coefficient first increased and then decreased. As a result, the power factor of the bulk materials first increased and then decreased, and a power factor of 1340 mu Wm(-1)K(-2) was achieved for the nanocomposite bulk materials with 0.25 wt% rGO at 150 degrees C.

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  • 35.
    Du, Yong
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Shanghai Inst Technol, Peoples R China.
    Xu, Jiayue
    Shanghai Inst Technol, Peoples R China.
    Paul, Biplab
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Flexible thermoelectric materials and devices2018In: APPLIED MATERIALS TODAY, ISSN 2352-9407, Vol. 12, p. 366-388Article, review/survey (Refereed)
    Abstract [en]

    Thermoelectric generators (TEGs) can directly convert waste heat into electrical power. In the last few decades, most research on thermoelectrics has focused on inorganic bulk thermoelectric materials and corresponding devices, and their thermoelectric properties have been significantly improved. An emerging topic is flexible devices, where the use of bulk inorganic materials is precluded by their inherent rigidity. The purpose of this paper is to review the research progress on flexible thermoelectric materials and generators, including theoretical principles for TEGs, conducting polymer TE materials, nanocomposites comprised of inorganic nanostructures in polymer matrices and fully inorganic flexible TE materials in nanostructured thin films. Approaches for flexible TEGs and components are reviewed, and remaining challenges discussed. (C) 2018 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

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  • 36.
    Edström, Daniel
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Orebro Univ, Sweden.
    Sangiovanni, Davide Giuseppe
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering. Ruhr Univ Bochum, Germany.
    Landälv, Ludvig
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Sandvik Coromant AB, Sweden.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Greene, Joseph E
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Univ Illinois, IL 61801 USA; Univ Illinois, IL 61801 USA; Natl Taiwan Univ Sci and Technol, Taiwan.
    Petrov, Ivan
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Univ Illinois, IL 61801 USA; Univ Illinois, IL 61801 USA.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Chirita, Valeriu
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Mechanical properties of VMoNO as a function of oxygen concentration: Toward development of hard and tough refractory oxynitrides2019In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 37, no 6, article id 061508Article in journal (Refereed)
    Abstract [en]

    Improved toughness is a central goal in the development of wear-resistant refractory ceramic coatings. Extensive theoretical and experimental research has revealed that NaCl-structure VMoN alloys exhibit surprisingly high ductility combined with high hardness and toughness. However, during operation, protective coatings inevitably oxidize, a problem that may compromise material properties and performance. Here, the authors explore the role of oxidation in altering VMoN properties. Density functional theory and theoretical intrinsic hardness models are used to investigate the mechanical behavior of cubic V0.5Mo0.5N1-xOx solid solutions as a function of the oxygen concentration x. Elastic constant and intrinsic hardness calculations show that oxidation does not degrade the mechanical properties of V0.5Mo0.5N. Electronic structure analyses indicate that the presence of oxygen reduces the covalent bond character, which slightly lowers the alloy strength and intrinsic hardness. Nevertheless, the character of metallic d-d states, which are crucial for allowing plastic deformation and enhancing toughness, remains unaffected. Overall, the authors results suggest that VMoNO oxynitrides, with oxygen concentrations as high as 50%, possess high intrinsic hardness, while still being ductile. Published by the AVS.

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  • 37. Order onlineBuy this publication >>
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Multifunctional nanostructured Ti-Si-C thin films2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this Thesis, I have investigated multifunctional nanostructured Ti-Si-C thin films synthesized by magnetron sputtering in the substrate-temperature range from room temperature to 900 °C. The studies cover high-temperature growth of Ti3SiC2 and Ti4SiC3, low-temperature growth of Ti-Si-C nanocomposites, and Ti-Si-C-based multi¬layers, as well as their electrical, mechanical, and thermal-stability properties. Ti3SiC2 and Ti4SiC3 were synthesized homoepitaxially onto bulk Ti3SiC2 from individual sputtering targets and heteroepitaxially onto Al2O3(0001) substrates from a Ti3SiC2 target at substrate temperatures of 700 – 900 °C. In the latter case, the film composition exhibits excess C compared to the nominal target composition due to differences between species in angular and energy distribution and gas-phase scattering processes. Ti buffering is shown to compensate for this excess C. The electrical-resistivity values of Ti3SiC2 and Ti4SiC3 thin films were measured to 21-32 uOhmcm and ~50 uOhmcm, respectively. The good conductivity is because the presence of Si layers enhances the relative strength of the metallic Ti-Ti bonds. The higher density of Si layers in Ti3SiC2 than in Ti4SiC3 explains why Ti3SiC2 is the better conductor of the two. Ti3SiC2 thin films are shown to be thermally stable up to 1000 – 1100 °C. Annealing at higher temperature results in decomposition of Ti3SiC2 by Si out-diffusion to the surface with subsequent evaporation. Above 1200 °C, TiCx layers recrystallized. Nanocomposites comprising nanocrystalline (nc-)TiC in an amorphous (a-)SiC matrix phase were deposited at substrate temperatures in the range 100 – 300 °C. These nc-TiC/a-SiC films exhibit low contact resistance in electrical contacts and a ductile deformation behavior due to rotation and gliding of nc-TiC grains in the matrix. The ductile mechanical properties of nc-TiC/a-SiC are actually more similar to those of Ti3SiC2, which is very ductile due to kinking and delamination, than to those of the brittle TiC. Epitaxial TiC/SiC multilayers deposited at ~550 °C were shown to contain cubic SiC layers up to a thickness of ~2 nm. Thicker SiC layers gives a-SiC due to the corresponding increase in interfacial strain energy leading to loss of coherent-layer growth. Nanoindentation of epitaxial Ti3SiC2/TiC0.67 nanolaminates showed inhibition of kink-band formation in Ti3SiC2, as the lamination with the less ductile TiC effectively hindered this mechanism.

    List of papers
    1. Homoepitaxial growth of Ti-Si-C MAX-phase thin films on bulk Ti3SiC2 substrates
    Open this publication in new window or tab >>Homoepitaxial growth of Ti-Si-C MAX-phase thin films on bulk Ti3SiC2 substrates
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    2007 (English)In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 304, no 1, p. 264-269Article in journal (Refereed) Published
    Abstract [en]

    Ti3SiC2 films were grown on polycrystalline Ti3SiC2 bulk substrates using DC magnetron sputtering. The crystallographic orientation of the film grains is shown to be determined by the respective substrate-grain orientation through homoepitaxial MAX-phase growth. For a film composition close to Ti:Si:C=3:1:2, the films predominantly consist of MAX phases, both Ti3SiC2 and the metastable Ti4SiC3. Lower Si content resulted in growth of TiC with Ti3SiC2 as a minority phase. Thus, MAX-phase heterostructures with preferred crystallographic relationships can also be realized.

    Keywords
    Scanning electron microscopy, Transmission electron microscopy, X-ray diffraction, Physical vapor deposition processes, Carbides, Nanomaterials
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-14471 (URN)10.1016/j.jcrysgro.2007.02.014 (DOI)
    Available from: 2007-05-14 Created: 2007-05-14 Last updated: 2017-12-13
    2. Magnetron sputtering of Ti3SiC2 thin films from a Ti3SiC2 compound target
    Open this publication in new window or tab >>Magnetron sputtering of Ti3SiC2 thin films from a Ti3SiC2 compound target
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    2007 (English)In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 25, no 5, p. 1381-1388Article in journal (Refereed) Published
    Abstract [en]

    Ti3 Si C2 thin films were synthesized by magnetron sputtering from Ti3 Si C2 and Ti targets. Sputtering from a Ti3 Si C2 target alone resulted in films with a C content of ∼50 at. % or more, due to gas-phase scattering processes and differences in angular and energy distributions between species ejected from the target. Addition of Ti to the deposition flux from a Ti3 Si C2 target is shown to bind the excess C in Ti Cx intergrown with Ti3 Si C2 and Ti4 Si C3. Additionally, a substoichiometric Ti Cx buffer layer is shown to serve as a C sink and enable the growth of Ti3 Si C2.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-14472 (URN)10.1116/1.2757178 (DOI)
    Available from: 2007-05-14 Created: 2007-05-14 Last updated: 2019-01-28
    3. Structural, electrical, and mechanical properties of nc-TiC/a-SiC nanocomposite thin films
    Open this publication in new window or tab >>Structural, electrical, and mechanical properties of nc-TiC/a-SiC nanocomposite thin films
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    2005 (English)In: Journal of Vacuum Science & Technology B, ISSN 1071-1023, E-ISSN 1520-8567, Vol. 23, no 6, p. 2486-2495Article in journal (Refereed) Published
    Abstract [en]

    We have synthesized Ti–Si–C nanocomposite thin films by dc magnetron sputtering from a Ti3SiC2 compound target in an Ar discharge on Si(100), Al2O3(0001), and Al substrates at temperatures from room temperature to 300  °C. Electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy showed that the films consisted of nanocrystalline (nc-) TiC and amorphous (a-) SiC, with the possible presence of a small amount of noncarbidic C. The growth mode was columnar, yielding a nodular film-surface morphology. Mechanically, the films exhibited a remarkable ductile behavior. Their nanoindentation hardness and E-modulus values were 20 and 290  GPa, respectively. The electrical resistivity was 330  µ  cm for optimal Ar pressure (4  mTorr) and substrate temperature (300  °C). The resulting nc-TiC/a-SiC films performed well as electrical contact material. These films' electrical-contact resistance against Ag was remarkably low, 6  µ at a contact force of 800  N compared to 3.2  µ for Ag against Ag. The chemical stability of the nc-TiC/a-SiC films was excellent, as shown by a Battelle flowing mixed corrosive-gas test, with no N, Cl, or S contaminants entering the bulk of the films.

    Keywords
    titanium compounds, silicon compounds, wide band gap semiconductors, nanocomposites, amorphous semiconductors, thin films, sputter deposition, electron microscopy, X-ray diffraction, X-ray photoelectron spectra, surface morphology, ductility, indentation, hardness, electrical resistivity, electrical contacts, contact resistance
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-14473 (URN)10.1116/1.2131081 (DOI)
    Available from: 2007-05-14 Created: 2007-05-14 Last updated: 2021-12-29
    4. Microstructure and electrical properties of Ti-Si-C-Ag nanocomposite thin films
    Open this publication in new window or tab >>Microstructure and electrical properties of Ti-Si-C-Ag nanocomposite thin films
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    2007 (English)In: Surface and Coatings Technology, ISSN 0257-8972, Vol. 201, no 14, p. 6465-6469Article in journal (Refereed) Published
    Abstract [en]

    Ti–Si–C–Ag nanocomposite coatings consisting of nanocrystalline TiC in an amorphous Si matrix with segregated Ag were deposited by dual magnetron sputtering from Ti3SiC2 and Ag targets. As evidenced by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, for Ag contents below 10 at.%, the Ag forms 10 nm large crystallites that are homogeneously distributed in the films. For higher Ag contents, coalescence during growth results in the formation of >  100 nm Ag islands on the film surface. The electrical resistivity of the coatings was measured in a four-point-probe setup, and ranged from 340 μΩcm (for Ti–Si–C coatings without Ag) to 40 μΩcm (for high Ag content).

    Keywords
    Sputtering, Titanium carbide, Silver; Resistivity, X-ray diffraction, Electron microscopy
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-14474 (URN)10.1016/j.surfcoat.2006.12.016 (DOI)
    Available from: 2007-05-14 Created: 2007-05-14 Last updated: 2016-08-31
    5. High-power impulse magnetron sputtering of Ti-Si-C thin films from a Ti3SiC2 compound target
    Open this publication in new window or tab >>High-power impulse magnetron sputtering of Ti-Si-C thin films from a Ti3SiC2 compound target
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    2006 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 4, p. 1731-1736Article in journal (Refereed) Published
    Abstract [en]

    We have deposited Ti-Si-C thin films using high-power impulse magnetron sputtering (HIPIMS) from a Ti3SiC2 compound target. The as-deposited films were composite materials with TiC as the main crystalline constituent. X-ray diffraction and photoelectron spectroscopy indicated that they also contained amorphous SiC, and for films deposited on inclined substrates, crystalline Ti5Si3Cx. The film morphology was dense and flat, while films deposited with dc magnetron sputtering under comparable conditions were rough and porous. Due to the high degree of ionization of the sputtered species obtained in HIPIMS, it is possible to control the film composition, in particular the C content, by tuning the substrate inclination angle, the Ar process pressure, and the bias voltage.

    Place, publisher, year, edition, pages
    Institutionen för fysik, kemi och biologi, 2006
    Keywords
    HIPIMS, Titanium silicon carbide
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:liu:diva-10437 (URN)10.1016/j.tsf.2006.06.015 (DOI)000242931900079 ()
    Note

    Original publication: J. Alami, P. Eklund, J. Emmerlich, O. Wilhelmsson, U. Jansson, H. Högberg, L. Hultman, & U. Helmersson, High-power impulse magnetron sputtering of Ti-Si-C thin films from a Ti3SiC2 compound target, 2006, Thin Solid Films, (515), 4, 1731-1736. http://dx.doi.org/10.1016/j.tsf.2006.06.015. Copyright: Elsevier B.V., http://www.elsevier.com/.

    Available from: 2007-12-14 Created: 2007-12-14 Last updated: 2017-12-14Bibliographically approved
    6. Electrical resistivity of Tin+1ACn (A = Si, Ge, Sn, n = 1–3) thin films
    Open this publication in new window or tab >>Electrical resistivity of Tin+1ACn (A = Si, Ge, Sn, n = 1–3) thin films
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    2007 (English)In: Journal of Materials Research, ISSN 0884-2914, E-ISSN 2044-5326, Vol. 22, no 8, p. 2279-2287Article in journal (Refereed) Published
    Abstract [en]

    We have investigated the electrical resistivity of (0001)-oriented Tin+1ACn (A = Si, Ge, Sn, n = 1–3) thin films deposited by magnetron sputtering onto Al2O3(0001) substrates at temperatures ranging from 500 to 950 °C. Four-point-probe measurements show that all films are good conductors with resistivity values of ∼21–51 μΩ cm for Ti–Si–C films, ∼15–50 μΩ cm for Ti–Ge–C films, and ∼46 μΩ cm for Ti2SnC. We find a general trend of decreasing resistivity with decreasing n for the Ti–Si–C and Ti–Ge–C systems due to the increased metallicity obtained with increasing density of A-element layers. We also show that crystalline quality and competitive growth of impurity phases affect the measured resistivity values. The effect of a given impurity phase largely depends on its location in the sample. Specifically, a TiCx layer in the center of the film constricts the current flow and results in an increased measured resistivity value. However, TiCx transition or seed layers at the substrate–film interface as well as surface segregation of Ge and Ti5Ge3Cx (for Ti–Ge–C) have only little effect on the measured resistivity values. For the Ti–Sn–C system, the resistivity is mainly influenced by the segregation of metallic Sn, yielding a wide spread in the measured values ranging from 20–46 μΩ cm, in the order of increased film purity.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-14476 (URN)10.1557/jmr.2007.0284 (DOI)
    Available from: 2007-05-14 Created: 2007-05-14 Last updated: 2017-12-13
    7. Photoemission studies of Ti3SiC2 and nanocrystalline-TiC/amorphous-SiC nanocomposite thin films
    Open this publication in new window or tab >>Photoemission studies of Ti3SiC2 and nanocrystalline-TiC/amorphous-SiC nanocomposite thin films
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    2006 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 74, no 4, p. 045417-Article in journal (Refereed) Published
    Abstract [en]

    Photoemissionstudies using synchrotron radiation have been performed on epitaxial Ti3SiC2(0001)and compound nanocrystalline (nc-)TiC/amorphous (a-)SiC thin films deposited by magnetronsputtering. As-introduced samples were found to be covered by surfaceoxides, SiOx and TiOx. These oxides could be removed byin-situ annealing to ~1000  °C. For as-annealed Ti3SiC2(0001), surface Si wasobserved and interpreted as originating from decomposition of Ti3SiC2 throughSi out-diffusion. For nc-TiC/a-SiC annealed in situ to ~1000  °C, thesurface instead exhibited a dominant contribution from graphitic carbon, alsowith the presence of Si, due to C and Siout-diffusion from the a-SiC compound or from grain boundaries.

    Keywords
    titanium compounds, silicon compounds, wide band gap semiconductors, nanocomposites, amorphous state, epitaxial layers, sputtered coatings, photoelectron spectra, surface composition, annealing, decomposition, surface diffusion, grain boundaries
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-14477 (URN)10.1103/PhysRevB.74.045417 (DOI)
    Available from: 2007-05-14 Created: 2007-05-14 Last updated: 2017-12-13
    8. Thermal stability of Ti3SiC2 thin films
    Open this publication in new window or tab >>Thermal stability of Ti3SiC2 thin films
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    2007 (English)In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 55, no 4, p. 1479-1488Article in journal (Refereed) Published
    Abstract [en]

    The thermal stability of Ti3SiC2(0 0 0 1) thin films is studied by in situ X-ray diffraction analysis during vacuum furnace annealing in combination with X-ray photoelectron spectroscopy, transmission electron microscopy and scanning transmission electron microscopy with energy dispersive X-ray analysis. The films are found to be stable during annealing at temperatures up to ∼1000 °C for 25 h. Annealing at 1100–1200 °C results in the rapid decomposition of Ti3SiC2 by Si out-diffusion along the basal planes via domain boundaries to the free surface with subsequent evaporation. As a consequence, the material shrinks by the relaxation of the Ti3C2 slabs and, it is proposed, by an in-diffusion of O into the empty Si-mirror planes. The phase transformation process is followed by the detwinning of the as-relaxed Ti3C2 slabs into (1 1 1)-oriented TiC0.67 layers, which begin recrystallizing at 1300 °C. Ab initio calculations are provided supporting the presented decomposition mechanisms.

    Keywords
    Ti3SiC2 thin films, Phase transformations, X-ray diffraction, Transmission electron microscopy, Ab initio electron theory
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-14478 (URN)10.1016/j.actamat.2006.10.010 (DOI)
    Available from: 2007-05-14 Created: 2007-05-14 Last updated: 2017-12-13
    9. Epitaxial TiC/SiC multilayers
    Open this publication in new window or tab >>Epitaxial TiC/SiC multilayers
    2007 (English)In: Physica status solidi (RRL): rapid research letters, ISSN 1862-6254, Vol. 1, no 3, p. 113-115Article in journal (Refereed) Published
    Abstract [en]

    Epitaxial TiC/SiC multilayers were grown by magnetron sputtering at a substrate temperature of 550 °C, where SiC is normally amorphous. The epitaxial TiC template induced growth of cubic SiC up to a thickness of ~2 nm. Thicker SiC layers result in a direct transition to growth of the metastable amorphous SiC followed by renucleation of nanocrystalline TiC layers

    Keywords
    61.10.Nz, 68.37.Lp, 68.55.-a, 81.05.Je, 81.07.Bk, 81.15.Kk
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-14479 (URN)10.1002/pssr.200701027 (DOI)
    Available from: 2007-05-14 Created: 2007-05-14 Last updated: 2016-08-31
    10. Intrusion-type deformation in epitaxial Ti3SiC2/TiCx nanolaminates
    Open this publication in new window or tab >>Intrusion-type deformation in epitaxial Ti3SiC2/TiCx nanolaminates
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    2007 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 91, no 12, p. 123124-Article in journal (Refereed) Published
    Abstract [en]

    We investigate the deformation of epitaxial Ti3 Si C2 (0001) Ti Cx (111) (x∼0.67) nanolaminates deposited by magnetron sputtering. Nanoindentation and transmission electron microscopy show that the Ti3 Si C2 layers deform via basal plane slip and intrusion into the TiC layers, suppressing kink-band and pile-up deformation behaviors analogous with monolithic Ti3 Si C2. This remarkable response to indentation is due to persistent slip in the TiC layers and prevention of gross slip throughout the nanolaminate by the interleaving Ti3 Si C2 layers. Hardness and Young's modulus were measured as ∼15 and ∼240 GPa, respectively.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-14480 (URN)10.1063/1.2789710 (DOI)
    Available from: 2007-05-14 Created: 2007-05-14 Last updated: 2017-12-13
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  • 38.
    Eklund, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Novel ceramic Ti-Si-C nanocomposite coatings for electrical contact applications2007In: Surface Engineering, ISSN 0267-0844, E-ISSN 1743-2944, Vol. 23, no 6, p. 406-411Article in journal (Refereed)
    Abstract [en]

    Nanocomposite coatings consisting of TiC nanocrystallties embedded in an amorphous SiC matrix (nc-TiC/a-SiC) have been produced using magnetron sputtering from a Ti3SiC2 target onto electrical contact components at a temperature below 300°C. The as deposited nanocomposites were employed as electrical contact materials. Results show that when contacted against Ag, they exhibit somewhat higher contact resistance than Ag against Ag, while preventing welding and potentially minimising wear. This is due to an adequate resistivity coupled with beneficial mechanical properties. The design of the nanoscale materials produced coatings with a relatively high nanoindentation hardness of 20 GPa, but with a ductile deformation behaviour. The ductility is explained by rotation and gliding of nc-TiC grains in the matrix. Therefore, the nanocomposite material can minimise problems with wear and welding while retaining low contact resistance. Consequently, this type of novel coating with appropriate mechanical properties offers a solution to problems in many electrical applications. Moreover, the use of physically vapour deposited coatings is promoted in some previously relatively unexploited areas of electrical contact applications. © 2007 Institute of Materials, Minerals and Mining.

  • 39.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Thin film growth and characterization of Ti-(Si,Ge)-C compounds2005Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis describes growth by de magnetron sputtering of thin film Ti-Si-C and Ti-Ge-C materials, with an emphasis on the deposition conditions for nanocomposite and epitaxial growth at low and high temperature processing, respectively. In the Ti-Si-C materials system, I have synthesized nanocomposite thin films from a Ti3SiC2 compound target in an Ar discharge on Si(100), Al2O3(0001), and Al substrates at low substrate temperature (300 oC and below). The films consisted ofnanocrystalline (nc-) TiC and amorphous (a-) SiC, with possible presence of a small amount of non-carbidic C. Mechanically, the films exhibited a remarkable ductile behavior. Their nanoindentation hardness and E-modulus values were 20 GPa and 290 GPa, respectively. The electrical resistivity was 330 μΩcm for optimal Ar pressure (4 mTorr) and substrate temperature (300 °C). The resulting nc-TiC/a-SiC films performed well as electrical contact material, exhibiting contact resistances against Ag as low as 6μΩ at a contact force of 800 N compared to 3.2 μΩ for Ag against Ag. The chemical stability of the nc-TiC/a-SiC films was excellent, as shown by a Battelle flowing mixed corrosive gas test, with no N, Cl, or S contaminants entering the bulk of the films. Furthermore, the thesis describes epitaxial growth on Al2O3(0001) substrates of single- crystal thin films of the Mn+1AXn phases Ti2GeC and Ti3GeC2, and a new phase Ti4GeC3 as well as two new intergrown MAX structures, Ti5Ge2C3 and Ti7Ge2C5. X-ray diffraction shows that Ti-Ge-C MAX-phases require somewhat higher deposition temperatures (1000 oC) in a narrower window than their Ti-Si-C correspondences do, while there are similarities in phase distribution. Nanoindentation reveals a Young's modulus of 300 GPa, lower than that of Ti3SiC2, 320 GPa. Four point probe measurements yield resistivity values of 50-200 μΩcm. The lowest value is obtained for phase-pure Ti3GeC2(0001) films.

    List of papers
    1. Structural, electrical, and mechanical properties of nc-TiC/a-SiC nanocomposite thin films
    Open this publication in new window or tab >>Structural, electrical, and mechanical properties of nc-TiC/a-SiC nanocomposite thin films
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    2005 (English)In: Journal of Vacuum Science & Technology B, ISSN 1071-1023, E-ISSN 1520-8567, Vol. 23, no 6, p. 2486-2495Article in journal (Refereed) Published
    Abstract [en]

    We have synthesized Ti–Si–C nanocomposite thin films by dc magnetron sputtering from a Ti3SiC2 compound target in an Ar discharge on Si(100), Al2O3(0001), and Al substrates at temperatures from room temperature to 300  °C. Electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy showed that the films consisted of nanocrystalline (nc-) TiC and amorphous (a-) SiC, with the possible presence of a small amount of noncarbidic C. The growth mode was columnar, yielding a nodular film-surface morphology. Mechanically, the films exhibited a remarkable ductile behavior. Their nanoindentation hardness and E-modulus values were 20 and 290  GPa, respectively. The electrical resistivity was 330  µ  cm for optimal Ar pressure (4  mTorr) and substrate temperature (300  °C). The resulting nc-TiC/a-SiC films performed well as electrical contact material. These films' electrical-contact resistance against Ag was remarkably low, 6  µ at a contact force of 800  N compared to 3.2  µ for Ag against Ag. The chemical stability of the nc-TiC/a-SiC films was excellent, as shown by a Battelle flowing mixed corrosive-gas test, with no N, Cl, or S contaminants entering the bulk of the films.

    Keywords
    titanium compounds, silicon compounds, wide band gap semiconductors, nanocomposites, amorphous semiconductors, thin films, sputter deposition, electron microscopy, X-ray diffraction, X-ray photoelectron spectra, surface morphology, ductility, indentation, hardness, electrical resistivity, electrical contacts, contact resistance
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-14473 (URN)10.1116/1.2131081 (DOI)
    Available from: 2007-05-14 Created: 2007-05-14 Last updated: 2021-12-29
    2. Epitaxial Ti2GeC, Ti3GeC2, and Ti4GeC3 MAX-phase thin films grown by magnetron sputtering
    Open this publication in new window or tab >>Epitaxial Ti2GeC, Ti3GeC2, and Ti4GeC3 MAX-phase thin films grown by magnetron sputtering
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    2005 (English)In: Journal of Materials Research, ISSN 0884-2914, E-ISSN 2044-5326, Vol. 20, no 4, p. 779-782Article in journal (Refereed) Published
    Abstract [en]

    We have grown single-crystal thin films of Ti2GeC and Ti3GeC2 and a new phase Ti4GeC3, as well as two new intergrown MAX-structures, Ti5Ge2C3 and Ti7Ge2C5. Epitaxial films were grown on Al2O3(0001) substrates at 1000 °C using direct current magnetron sputtering. X-ray diffraction shows that Ti–Ge–C MAX-phases require higher deposition temperatures in a narrower window than their Ti–Si–C correspondences do, while there are similarities in phase distribution. Nanoindentation reveals a Young’s modulus of 300 GPa, lower than that of Ti3SiC2. Four-point probe measurements yield resistivity values of 50–200 μΩcm. The lowest value is obtained for phase-pure Ti3GeC2(0001) films.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-28436 (URN)10.1557/JMR.2005.0105 (DOI)13576 (Local ID)13576 (Archive number)13576 (OAI)
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2021-12-29
  • 40.
    Eklund, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Beckers, Manfred
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Frodelius, Jenny
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    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.
    Magnetron sputtering of Ti3SiC2 thin films from a Ti3SiC2 compound target2007In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 25, no 5, p. 1381-1388Article in journal (Refereed)
    Abstract [en]

    Ti3 Si C2 thin films were synthesized by magnetron sputtering from Ti3 Si C2 and Ti targets. Sputtering from a Ti3 Si C2 target alone resulted in films with a C content of ∼50 at. % or more, due to gas-phase scattering processes and differences in angular and energy distributions between species ejected from the target. Addition of Ti to the deposition flux from a Ti3 Si C2 target is shown to bind the excess C in Ti Cx intergrown with Ti3 Si C2 and Ti4 Si C3. Additionally, a substoichiometric Ti Cx buffer layer is shown to serve as a C sink and enable the growth of Ti3 Si C2.

  • 41.
    Eklund, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Beckers, Manfred
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Jansson, Ulf
    Uppsala University.
    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.
    The M(n+1)AX(n) phases: Materials science and thin-film processing2010In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 518, no 8, p. 1851-1878Article, review/survey (Refereed)
    Abstract [en]

    This article is a Critical review of the M(n + 1)AX(n) phases ("MAX phases", where n = 1, 2, or 3) from a materials science perspective. MAX phases are a class of hexagonal-structure ternary carbides and nitrides ("X") of a transition metal ("M") and an A-group element. The most well known are Ti2AlC, Ti3SiC2, and Ti4AlN3. There are similar to 60 MAX phases with at least 9 discovered in the last five years alone. What makes the MAX phases fascinating and potentially useful is their remarkable combination of chemical, physical, electrical, and mechanical properties, which in many ways combine the characteristics of metals and ceramics. For example, MAX phases are typically resistant to oxidation and corrosion, elastically stiff, but at the same time they exhibit high thermal and electrical conductivities and are machinable. These properties stem from an inherently nanolaminated crystal structure, with M1 + nXn slabs intercalated with pure A-element layers. The research on MAX phases has been accelerated by the introduction of thin-film processing methods. Magnetron sputtering and arc deposition have been employed to synthesize single-crystal material by epitaxial growth, which enables studies of fundamental material properties. However, the surface-initiated decomposition of M(n + 1)AX(n) thin films into MX compounds at temperatures of 1000-1100 degrees C is much lower than the decomposition temperatures typically reported for the corresponding bulk material. We also review the prospects for low-temperature synthesis, which is essential for deposition of MAX phases onto technologically important substrates. While deposition of MAX phases from the archetypical Ti-Si-C and Ti-Al-N systems typically requires synthesis temperatures of similar to 800 degrees C, recent results have demonstrated that V2GeC and Cr2AlC can be deposited at similar to 450 degrees C. Also, thermal spray of Ti2AlC powder has been used to produce thick coatings. We further treat progress in the use of first-principle calculations for predicting hypothetical MAX phases and their properties. Together with advances in processing and materials analysis, this progress has led to recent discoveries of numerous new MAX phases such as Ti4SiC3, Ta4AlC3. and Ti3SnC2. Finally, important future research directions are discussed. These include charting the unknown regions in phase diagrams to discover new equilibrium and metastable phases, as well as research challenges in understanding their physical properties, such as the effects of anisotropy, impurities, and vacancies on the electrical properties, and unexplored properties such as Superconductivity, magnetism, and optics.

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    FULLTEXT01
  • 42.
    Eklund, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Bugnet, Matthieu
    University of Poitiers.
    Mauchamp, Vincent
    University of Poitiers.
    Dubois, Sylvain
    University of Poitiers.
    Tromas, Christophe
    University of Poitiers.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Piraux, Luc
    Catholic University Louvain.
    Gence, Loiek
    Catholic University Louvain.
    Jaouen, Michel
    University of Poitiers.
    Cabioch, Thierry
    University of Poitiers.
    Epitaxial growth and electrical transport properties of Cr(2)GeC thin films2011In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 84, no 7, p. 075424-Article in journal (Refereed)
    Abstract [en]

    Cr(2)GeC thin films were grown by magnetron sputtering from elemental targets. Phase-pure Cr(2)GeC was grown directly onto Al(2)O(3)(0001) at temperatures of 700-800 degrees C. These films have an epitaxial component with the well-known epitaxial relationship Cr(2)GeC(0001)//Al(2)O(3)(0001) and Cr(2)GeC(11andlt;(2) overbarandgt;0)//Al(2)O(3)(1andlt;(1)over barandgt;00) or Cr(2)GeC(11andlt;(2) over barandgt;0)//Al(2)O(3)(andlt;(1) over barandgt;2andlt;(1) over barandgt;0). There is also a large secondary grain population with (10andlt;(1)overbarandgt;3) orientation. Deposition onto Al(2)O(3)(0001) with a TiN(111) seed layer and onto MgO(111) yielded growth of globally epitaxial Cr(2)GeC(0001) with a virtually negligible (10andlt;(1) over barandgt;3) contribution. In contrast to the films deposited at 700-800 degrees C, the ones grown at 500-600 degrees C are polycrystalline Cr(2)GeC with (10andlt;(1) over barandgt;0)-dominated orientation; they also exhibit surface segregations of Ge as a consequence of fast Ge diffusion rates along the basal planes. The room-temperature resistivity of our samples is 53-66 mu Omega cm. Temperature-dependent resistivity measurements from 15-295 K show that electron-phonon coupling is important and likely anisotropic, which emphasizes that the electrical transport properties cannot be understood in terms of ground state electronic structure calculations only.

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  • 43.
    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.

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  • 44.
    Eklund, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Emmerlich, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    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.
    Wilhelmsson, Ola
    Uppsala universitet.
    Jansson, Ulf
    Uppsala universitet.
    Isberg, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Synthesis and characterization of Ti-Si-C compounds for electrical contact applications2005In: IEEE Holm Conference on Electrical Contacts,2005, Piscataway: IEEE , 2005, p. 277-283Conference paper (Refereed)
  • 45.
    Eklund, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Emmerlich, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Wilhelmsson, Ola
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Sweden.
    Isberg, Peter
    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 O. Å.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Jansson, Ulf
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Sweden.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Structural, electrical, and mechanical properties of nc-TiC/a-SiC nanocomposite thin films2005In: Journal of Vacuum Science & Technology B, ISSN 1071-1023, E-ISSN 1520-8567, Vol. 23, no 6, p. 2486-2495Article in journal (Refereed)
    Abstract [en]

    We have synthesized Ti–Si–C nanocomposite thin films by dc magnetron sputtering from a Ti3SiC2 compound target in an Ar discharge on Si(100), Al2O3(0001), and Al substrates at temperatures from room temperature to 300  °C. Electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy showed that the films consisted of nanocrystalline (nc-) TiC and amorphous (a-) SiC, with the possible presence of a small amount of noncarbidic C. The growth mode was columnar, yielding a nodular film-surface morphology. Mechanically, the films exhibited a remarkable ductile behavior. Their nanoindentation hardness and E-modulus values were 20 and 290  GPa, respectively. The electrical resistivity was 330  µ  cm for optimal Ar pressure (4  mTorr) and substrate temperature (300  °C). The resulting nc-TiC/a-SiC films performed well as electrical contact material. These films' electrical-contact resistance against Ag was remarkably low, 6  µ at a contact force of 800  N compared to 3.2  µ for Ag against Ag. The chemical stability of the nc-TiC/a-SiC films was excellent, as shown by a Battelle flowing mixed corrosive-gas test, with no N, Cl, or S contaminants entering the bulk of the films.

  • 46.
    Eklund, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Frodelius, Jenny
    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.
    Magnfält, Daniel
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, The Institute of Technology.
    Epitaxial growth of gamma-Al2O3 on Ti2AlC(0001) by reactive high-power impulse magnetron sputtering2014In: AIP Advances, E-ISSN 2158-3226, Vol. 4, no 1, p. 017138-Article in journal (Refereed)
    Abstract [en]

    Al2O3 was deposited by reactive high-power impulse magnetron sputtering at 600 degrees C onto pre-deposited Ti2AlC(0001) thin films on alpha-Al2O3(0001) substrates. The Al2O3 was deposited to a thickness of 65 nm and formed an adherent layer of epitaxial gamma-Al2O3(111) as shown by transmission electron microscopy. The demonstration of epitaxial growth of gamma-Al2O3 on Ti2AlC (0001) open prospects for growth of crystalline alumina as protective coatings on Ti2AlC and related nanolaminated materials. The crystallographic orientation relationships are gamma-Al2O3(111)//Ti2AlC(0001) (out-of-plane) and gamma-Al2O3(2 (2) over bar0)//Ti2AlC(11 (2) over bar0) (in-plane) as determined by electron diffraction. Annealing in vacuum at 900 degrees C resulted in partial decomposition of the Ti2AlC by depletion of Al and diffusion into and through the gamma-Al2O3 layer.

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  • 47.
    Eklund, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    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.
    Epitaxial TiC/SiC multilayers2007In: Physica status solidi (RRL): rapid research letters, ISSN 1862-6254, Vol. 1, no 3, p. 113-115Article in journal (Refereed)
    Abstract [en]

    Epitaxial TiC/SiC multilayers were grown by magnetron sputtering at a substrate temperature of 550 °C, where SiC is normally amorphous. The epitaxial TiC template induced growth of cubic SiC up to a thickness of ~2 nm. Thicker SiC layers result in a direct transition to growth of the metastable amorphous SiC followed by renucleation of nanocrystalline TiC layers

  • 48.
    Eklund, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Joelsson, Torbjörn
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Ljungcrantz, Henrik
    Impact Coatings AB, Linköping, Sweden.
    Wilhelmsson, Ola
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Uppsala, Sweden.
    Czigany, Zsolt
    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.
    Microstructure and electrical properties of Ti-Si-C-Ag nanocomposite thin films2007In: Surface and Coatings Technology, ISSN 0257-8972, Vol. 201, no 14, p. 6465-6469Article in journal (Refereed)
    Abstract [en]

    Ti–Si–C–Ag nanocomposite coatings consisting of nanocrystalline TiC in an amorphous Si matrix with segregated Ag were deposited by dual magnetron sputtering from Ti3SiC2 and Ag targets. As evidenced by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, for Ag contents below 10 at.%, the Ag forms 10 nm large crystallites that are homogeneously distributed in the films. For higher Ag contents, coalescence during growth results in the formation of >  100 nm Ag islands on the film surface. The electrical resistivity of the coatings was measured in a four-point-probe setup, and ranged from 340 μΩcm (for Ti–Si–C coatings without Ag) to 40 μΩcm (for high Ag content).

  • 49.
    Eklund, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Kerdsongpanya, Sit
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Alling, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Max Planck Institute Eisenforsch GmbH, Germany.
    Transition-metal-nitride-based thin films as novel energy harvesting materials2016In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 4, no 18, p. 3905-3914Article in journal (Refereed)
    Abstract [en]

    The last few years have seen a rise in the interest in early transition-metal and rare-earth nitrides, primarily based on ScN and CrN, for energy harvesting by thermoelectricity and piezoelectricity. This is because of a number of important advances, among those the discoveries of exceptionally high piezoelectric coupling coefficient in (Sc,Al)N alloys and of high thermoelectric power factors of ScN-based and CrN-based thin films. These materials also constitute well-defined model systems for investigating thermodynamics of mixing for alloying and nanostructural design for optimization of phase stability and band structure. These features have implications for and can be used for tailoring of thermoelectric and piezoelectric properties. In this highlight article, we review the ScN-and CrN-based transition-metal nitrides for thermoelectrics, and drawing parallels with piezoelectricity. We further discuss these materials as a models systems for general strategies for tailoring of thermoelectric properties by integrated theoretical-experimental approaches.

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    fulltext
  • 50.
    Eklund, Per
    et al.
    University of Aarhus, Denmark.
    Mikkelsen, Niels-Jörgen
    CemeCon Scandinavia A/S, Åbyhøj, Denmark.
    Sillassen, Mikael
    University of Aarhus, Denmark.
    Bienk, Ewa
    CemeCon Scandinavia A/S, Åbyhøj, Denmark.
    Böttiger, Jörgen
    University of Aarhus, Denmark.
    Chromium oxide-based multilayer coatings deposited by reactive magnetron sputtering in an industrial setup2008In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 203, no 1, p. 156-159Article in journal (Refereed)
    Abstract [en]

    Chromium oxide-based multilayers were deposited by reactive magnetron sputtering in an industrial setup by employing one-fold substrate rotation and cyclic variation of the O2 flow. This simple method allows deposition of multilayers comprising alternating layers of ~ 1 μm thickness of columnar α-Cr2O3 and mixed layers consisting of ~ 50 nm-thick sublayers of amorphous CrOx and nanocrystalline Cr2O3.

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