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  • 1.
    Amin, Gul
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Sandberg, M. O.
    Acreo AB, Printed Electronics, P.O. Box 787, 60117 Norrköping, Sweden.
    Zainelabdin, Ahmed
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zaman, Siama
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Scale-up synthesis of ZnO nanorods for printing inexpensive ZnO/polymer white light-emitting diode2012In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 47, no 11, p. 4726-4731Article in journal (Refereed)
    Abstract [en]

    In this study, possibilities of scaling up the synthesis of zinc oxide (ZnO) nanorods (NRs) by the hydrothermal method have been explored. It was found that batches yielding several grams can easily be made using common and easily available materials. Further, a printable composition was fabricated by mixing the obtained ZnO NRs into a common solvent-based screen printable varnish. Scanning electron microscope, high-resolution transmission electron microscope, X-ray diffraction, UV–vis spectroscopy analysis of the scaled up batch indicated that the ZnO nanostructures were of NRs shape, well crystalline and having less defects. Using the ZnO NRs-based printable composition a device fabrication on a flexible substrate was demonstrated, producing a flexible light-emitting device being highly tolerant to bending.

  • 2.
    Ekström, Erik
    et al.
    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.
    Fournier, Daniele
    Sorbonne Univ, France.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Ene, Vladimir-Lucian
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. Univ Politehn Bucuresti, Romania.
    Van Nong, Ngo
    Tech Univ Denmark, Denmark.
    Eriksson, Fredrik
    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.
    Paul, Biplab
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Formation mechanism and thermoelectric properties of CaMnO3 thin films synthesized by annealing of Ca0.5Mn0.5O films2019In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 54, no 11, p. 8482-8491Article in journal (Refereed)
    Abstract [en]

    A two-step synthesis approach was utilized to grow CaMnO3 on M-, R- and C-plane sapphire substrates. Radio-frequency reactive magnetron sputtering was used to grow rock-salt-structured (Ca, Mn)O followed by a 3-h annealing step at 800 degrees C in oxygen flow to form the distorted perovskite phase CaMnO3. The effect of temperature in the post-annealing step was investigated using x-ray diffraction. The phase transformation to CaMnO3 started at 450 degrees C and was completed at 550 degrees C. Films grown on R- and C-plane sapphire showed similar structure with a mixed orientation, whereas the film grown on M-plane sapphire was epitaxially grown with an out-of-plane orientation in the [202] direction. The thermoelectric characterization showed that the film grown on M-plane sapphire has about 3.5 times lower resistivity compared to the other films with a resistivity of 0.077cm at 500 degrees C. The difference in resistivity is a result from difference in crystal structure, single orientation for M-plane sapphire compared to mixed for R- and C-plane sapphire. The highest absolute Seebeck coefficient value is -350 mu VK-1 for all films and is decreasing with temperature.

  • 3.
    Garbrecht, Magnus
    et al.
    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.
    Fawey, Mohammed H.
    KIT, Germany; TUD, Germany.
    Sands, Timothy D.
    Virginia Tech, VA 24061 USA; Virginia Tech, VA 24061 USA.
    Saha, Bivas
    University of Calif Berkeley, CA 94720 USA.
    Tailoring of surface plasmon resonances in TiN/(Al0.72Sc0.28)N multilayers by dielectric layer thickness variation2018In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 53, no 6, p. 4001-4009Article in journal (Refereed)
    Abstract [en]

    Alternative designs of plasmonic metamaterials for applications in solar energy-harvesting devices are necessary due to pure noble metal-based nanostructures incompatibility with CMOS technology, limited thermal and chemical stability, and high losses in the visible spectrum. In the present study, we demonstrate the design of a material based on a multilayer architecture with systematically varying dielectric interlayer thicknesses that result in a continuous shift of surface plasmon energy. Plasmon resonance characteristics of metal/semiconductor TiN/(Al,Sc)N multilayer thin films with constant TiN and increasing (Al,Sc)N interlayer thicknesses were analyzed using aberration-corrected and monochromated scanning transmission electron microscopy-based electron energy loss spectroscopy (EELS). EEL spectrum images and line scans were systematically taken across layer interfaces and compared to spectra from the centers of the respective adjacent TiN layer. While a constant value for the TiN bulk plasmon resonance of about 2.50 eV was found, the surface plasmon resonance energy was detected to continuously decrease with increasing (Al,Sc)N interlayer thickness until 2.16 eV is reached. This effect can be understood to be the result of resonant coupling between the TiN bulk and surface plasmons across the dielectric interlayers at very low (Al,Sc)N thicknesses. That energy interval between bulk and decreasing surface plasmon resonances corresponds to wavelengths in the visible spectrum. This shows the potential of tailoring the materials plasmonic response by controlling the (Al,Sc)N interlayer thickness, making TiN-based multilayers good prospects for plasmonic metamaterials in energy devices.

  • 4.
    Garbrecht, Magnus
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Schroeder, Jeremy
    Linköping University, Department of Physics, Chemistry and Biology. 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.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Saha, Bivas
    University of Calif Berkeley, CA 94720 USA.
    Sands, Timothy D.
    Virginia Tech, VA 24061 USA; Virginia Tech, VA 24061 USA.
    Microstructural evolution and thermal stability of HfN/ScN, ZrN/ScN, and Hf0.5Zr0.5N/ScN metal/semiconductor superlattices2016In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 51, no 17, p. 8250-8258Article in journal (Refereed)
    Abstract [en]

    Nitride-based metal/semiconductor superlattices for possible applications as thermoelectric, plasmonic, and hard coating materials have been grown by magnetron sputtering. Since long-time thermal stability of the superlattices is crucial for these applications, the atomic scale microstructure and its evolution under annealing to working temperatures were investigated with high-resolution transmission electron microscopy methods. We report on epitaxial growth of three cubic superlattice systems (HfN/ScN, ZrN/ScN, and Hf0.5Zr0.5N/ScN) that show long-time thermal stability (annealing up to 120 h at 950 degrees C) as monitored by scanning transmission electron microscopy-based energy-dispersive X-ray spectroscopy. No interdiffusion between the metal and semiconductor layers could be observed for any of the present systems under long-time annealing, which is in contrast to earlier attempts on similar superlattice structures based on TiN as the metallic compound. Atomically resolved high-resolution transmission electron microscopy imaging revealed that even though the superlattice curves towards the substrate at regular interval column boundaries originating from threading dislocations close to the substrate interface, the cubic lattice continues coherently across the boundaries. It is found that the boundaries themselves are alloyed along the entire growth direction, while in their vicinity nanometer-size inclusions of metallic phases are observed that could be identified as the zinc blende phase of same stoichiometry as the parent rock salt transition metal nitride phase. Our results demonstrate the longtime thermal stability of metal/semiconductor superlattices based on Zr and Hf nitrides.

  • 5.
    Gharavi, Mohammad Amin
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Armiento, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Alling, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering. Max Planck Institute Eisenforsch GmbH, Germany.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Theoretical study of phase stability, crystal and electronic structure of MeMgN2 (Me = Ti, Zr, Hf) compounds2018In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 53, no 6, p. 4294-4305Article in journal (Refereed)
    Abstract [en]

    Scandium nitride has recently gained interest as a prospective compound for thermoelectric applications due to its high Seebeck coefficient. However, ScN also has a relatively high thermal conductivity, which limits its thermoelectric efficiency and figure of merit (zT). These properties motivate a search for other semiconductor materials that share the electronic structure features of ScN, but which have a lower thermal conductivity. Thus, the focus of our study is to predict the existence and stability of such materials among inherently layered equivalent ternaries that incorporate heavier atoms for enhanced phonon scattering and to calculate their thermoelectric properties. Using density functional theory calculations, the phase stability of TiMgN2, ZrMgN2 and HfMgN2 compounds has been calculated. From the computationally predicted phase diagrams for these materials, we conclude that all three compounds are stable in these stoichiometries. The stable compounds may have one of two competing crystal structures: a monoclinic structure (LiUN2 prototype) or a trigonal superstructure (NaCrS2 prototype; RmH). The band structure for the two competing structures for each ternary is also calculated and predicts semiconducting behavior for all three compounds in the NaCrS2 crystal structure with an indirect band gap and semiconducting behavior for ZrMgN2 and HfMgN2 in the monoclinic crystal structure with a direct band gap. Seebeck coefficient and power factors are also predicted, showing that all three compounds in both the NaCrS2 and the LiUN2 structures have large Seebeck coefficients. The predicted stability of these compounds suggests that they can be synthesized by, e.g., physical vapor deposition.

  • 6.
    Gharavi, Mohammad Amin
    et al.
    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.
    Eriksson, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Balke, B.
    Univ Stuttgart, Germany.
    Fournier, D.
    Sorbonne Univ, France.
    Le Febvrier, Arnaud
    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.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Synthesis and characterization of single-phase epitaxial Cr2N thin films by reactive magnetron sputtering2019In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 54, no 2, p. 1434-1442Article in journal (Refereed)
    Abstract [en]

    Cr2N is commonly found as a minority phase or inclusion in stainless steel, CrN-based hard coatings, etc. However, studies on phase-pure material for characterization of fundamental properties are limited. Here, Cr2N thin films were deposited by reactive magnetron sputtering onto (0001) sapphire substrates. X-ray diffraction and pole figure texture analysis show Cr2N (0001) epitaxial growth. Scanning electron microscopy imaging shows a smooth surface, while transmission electron microscopy and X-ray reflectivity show a uniform and dense film with a density of 6.6gcm(-3), which is comparable to theoretical bulk values. Annealing the films in air at 400 degrees C for 96h shows little signs of oxidation. Nano-indentation shows an elastic-plastic behavior with H=18.9GPa and E-r=265GPa. The moderate thermal conductivity is 12Wm(-1)K(-1), and the electrical resistivity is 70cm. This combination of properties means that Cr2N may be of interest in applications such as protective coatings, diffusion barriers, capping layers and contact materials.

  • 7.
    Hussain, I.
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Bano, Nargis
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Hussain, S
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Study of intrinsic white light emission and its components from ZnO-nanorods/p-polymer hybrid junctions grown on glass substrates2011In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 46, no 23, p. 7437-7442Article in journal (Refereed)
    Abstract [en]

    We report white-light luminescence from ZnO-organic hybrid light emitting diodes grown on glass substrate by low temperature aqueous chemical growth. The configuration used for the hybrid white light emitting diodes (HWLEDs) consists of two-layers of polymers (PEDOT:PSS/PFO) on glass with top ZnO nanorods. Electroluminescence spectra of the HWLEDs demonstrate the combination of emission bands arising from the radiative recombination in polymer and ZnO nanorods. In order to distinguish emission bands we used a Gaussian function to simulate the experimental data. The emitted white light was found to be the superposition of a blue line at 454 nm, a green emission at 540 nm, orange line at 617 nm, and finally a red emission at 680 nm. The transitions causing these emissions are identified and discussed in terms of the energy band diagram of the hybrid junction. Color coordinates measurement of the WLED reveals that the emitted light has a white impression with 70 color rendering index and correlated color temperature 5500 K. Comparison between ITO and aluminum top contacts and its influence on the emitted intensity is also discussed.

  • 8.
    Khan, Azam
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hussain, Mushtaque
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Ali Abbasi, Mazhar
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hussain Ibupoto, Zafar
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Analysis of junction properties of gold-zinc oxide nanorods-based Schottky diode by means of frequency dependent electrical characterization on textile2014In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 49, no 9, p. 3434-3441Article in journal (Refereed)
    Abstract [en]

    Present work is an effort to reveal the junction properties of gold/zinc oxide (ZnO) nanorods-based Schottky diode by using the frequency dependent electrical properties. The most important electrical parameters such as conductance, resistance, capacitance, and impedance were studied as function of frequency across the series of AC voltages. Moreover, current density-voltage (J-V) was measured to know the performance of present Schottky diode. The effect of native defects was also studied by using cathodoluminescence spectroscopy measured at different accelerating voltage. The textile substrate was used for the growth of ZnO nanorods by using the aqueous chemical growth method and Schottky diode fabrication. Diode fabrication on textile fabric is a step forward toward the fabrication of electronic devices on nonconventional, economical, soft, light weight, flexible, wearable, washable, recyclable, reproducible, and nontoxic substrate.

  • 9.
    Le Febvrier, Arnaud
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. University of Rennes 1, France.
    Deputier, S.
    University of Rennes 1, France.
    Demange, V.
    University of Rennes 1, France.
    Bouquet, V.
    University of Rennes 1, France.
    Galca, A. C.
    National Institute Mat Phys, Romania.
    Iuga, A.
    National Institute Mat Phys, Romania.
    Pintilie, L.
    National Institute Mat Phys, Romania.
    Guilloux-Viry, M.
    University of Rennes 1, France.
    Effect of in-plane ordering on dielectric properties of highly {111}-oriented bismuth-zinc-niobate thin films2017In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 52, no 19, p. 11306-11313Article in journal (Refereed)
    Abstract [en]

    Bi1.5-xZn0.92-yNb1.5O6.92-delta (BZN) thin films were grown by pulsed laser deposition on two different Pt-covered substrates, namely textured {111} Pt/TiO2/SiO2/(100) Si substrate (Pt/Si) and epitaxial {111} Pt/R-plane sapphire substrate (Pt/sapphire). In both cases, the BZN films present {111} and {100} out-of-plane orientations, in relative ratios of 65: 35 on Pt/Si and 80: 20 on Pt/sapphire, respectively. The film grown on Pt/Si is textured, while the film deposited on Pt/sapphire presents epitaxial-like relationships with the substrate, for both out-of-plane orientations. Dielectric measurements were taken on both types of thin films, using Pt/BZN/Pt planar capacitor structures. The BZN/Pt/sapphire film presents higher dielectric constant (245 at 100 kHz) and higher tunability (12% at 600 kV/cm) than the BZN/Pt/Si film (200; 6%), while the dielectric losses values are nearly same (similar to 0.05).

  • 10.
    Liang, S.
    et al.
    US DOE-National Energy Technology Laboratory, Pittsburgh, PA, USA and University of Pittsburgh, USA.
    Broitman, Esteban
    Carnegie Mellon University, Pittsburgh, PA, USA .
    Wang, Y.
    US DOE-National Energy Technology Laboratory, Pittsburgh, PA, USA and University of Pittsburgh, USA.
    Cao, A.
    US DOE-National Energy Technology Laboratory, Pittsburgh, PA, USA and University of Pittsburgh, USA.
    Veser, G.
    US DOE-National Energy Technology Laboratory, Pittsburgh, PA, USA and University of Pittsburgh, USA.
    Highly stable, mesoporous mixed lanthanum–cerium oxides with tailored structure and reducibility2011In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 46, no 9, p. 2928-2937Article in journal (Refereed)
    Abstract [en]

    Pure and mixed lanthanum and cerium oxides were synthesized via a reverse microemulsion-templated route. This approach yields highly homogeneous and phase-stable mixed oxides with high surface areas across the entire range of La:Ce ratios from pure lanthana to pure ceria. Surprisingly, all mixed oxides show the fluorite crystal structure of ceria, even for lanthanum contents as high as 90%. Varying the La:Ce ratio not only allows tailoring of the oxide morphology (lattice parameter, pore structure, particle size, and surface area), but also results in a fine-tuning of the reducibility of the oxide which can be explained by the creation of oxygen vacancies in the ceria lattice upon La addition. Such finely controlled syntheses, which enable the formation of stable, homogeneous mixed oxides across the entire composition range, open the path towards functional tailoring of oxide materials, such as rational catalyst design via fine-tuning of redox activity.

  • 11.
    Lundberg, Mattias
    et al.
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Saarimäki, Jonas
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Moverare, Johan
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Peng, Ru Lin
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Effective X-ray Elastic Constant of Cast Iron2018In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 53, no 4, p. 2766-2773Article in journal (Refereed)
    Abstract [en]

    X-ray diffraction is a non-destructive method used for strain measurements in crystalline materials. Conversion of strain to stress can be achieved using the X-ray elastic constants (XEC), s1 and ½s2. The sin2ψ method was used during in situ loading to determine XEC for flake, vermicular, and spherical graphite iron. A fully pearlitic steel was used as reference. Uniaxial testing was conducted on the cast iron to create a homogeneous strain field, as well as four-point bending in both tension and compression due to the tension/compression asymmetry. The commonly used XEC value ½s2 = 5.81 × 10−6 MPa−1 is theoretically derived from an α-Fe single crystal. When investigating materials that contain ferrite, such as polycrystalline cast iron, this value is not accurate. Determination of an effective XEC for polycrystalline cast iron yields a better correlation between the measured microstrains and the properties observed on a macroscopic scale. The need for an effective XEC is evident, especially when it comes to model validation of, for example, casting simulations. Effective XEC values have been determined for flake, vermicular, and spherical graphite iron. The determined value is lower than the theoretical value.

  • 12.
    Mockuté, Aurelija
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Dahlqvist, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    O A Persson, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Oxygen incorporation in Ti2AlC thin films studied by electron energy loss spectroscopy and ab initio calculations2013In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 48, no 10, p. 3686-3691Article in journal (Refereed)
    Abstract [en]

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

  • 13.
    Mockuté, Aurelija
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Persson, Per O A
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Ingason, Arni Sigurdur
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Magnus, F.
    Uppsala University, Sweden .
    Olafsson, S.
    University of Iceland, Iceland .
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Structural and magnetic properties of (Cr1-xMnx)(5)Al-8 solid solution and structural relation to hexagonal nanolaminates2014In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 49, no 20, p. 7099-7104Article in journal (Refereed)
    Abstract [en]

    Electron microscopy is used to reveal the competitive epitaxial growth of bcc structure (Cr1-x Mn (x) )(5)Al-8 and (Cr1-y Mn (y) )(2)AlC [M (n+1)AX (n) (MAX)] phase during both magnetron sputtering and arc deposition. X-ray diffraction theta-2 theta measurements display identical peak positions of (000n)-oriented MAX phase and (Cr1-x Mn (x) )(5)Al-8, due to the interplanar spacing of (Cr1-x Mn (x) )(5)Al-8 that matches exactly half a unit cell of (Cr1-y Mn (y) )(2)AlC. Vibrating sample magnetometry shows that a thin film exclusively consisting of (Cr1-x Mn (x) )(5)Al-8 exhibits a magnetic response, implying that the potential presence of this phase needs to be taken into consideration when evaluating the magnetic properties of (Cr, Mn)(2)AlC.

  • 14.
    Mouzon, Johanne
    et al.
    Luleå University of Technology.
    Glowacki, Emily
    Luleå University of Technology.
    Oden, Magnus
    Luleå University of Technology.
    Comparison between slip-casting and uniaxial pressing for the fabrication of translucent yttria ceramics2008In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 43, no 8, p. 2849-2856Article in journal (Refereed)
    Abstract [en]

    Slip casting and uniaxial pressing were compared as first consolidation stages prior to cold isostatic pressing (CIP) to produce translucent yttria ceramics. In the first step, yttria slurries suitable for slip casting were prepared. The viscosity was optimized with respect to the starting agglomeration state, amount of dispersant, milling time, and number of milling balls. Secondly, pellets were prepared either by slip casting or uniaxial pressing and then cold-isostatically pressed. Finally, the pellets were made translucent by a combination of pre-sintering and hot isostatic pressing (HIP). Although slip-cast and pressed samples exhibited similar green-body densities after CIP and pre-sintering, the samples prepared by slip casting were more homogeneous in terms of translucency and microstructure throughout their bodies. This was attributed to the ability of slip casting to minimize density gradients during packing, and to the beneficial effect of ball-milling to remove larger agglomerates before casting. Therefore, slip casting as a first consolidation stage prior to CIP appears to be more suitable than uniaxial pressing in order to prepare homogeneous optical ceramics.

  • 15.
    Nijikovsky, Boris
    et al.
    Technion Israel Institute Technology, Israel.
    Richardson, Jacob J.
    University of Calif Santa Barbara, CA 93106 USA.
    Garbrecht, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    DenBaars, Steven P.
    University of Calif Santa Barbara, CA 93106 USA.
    Kaplan, Wayne D.
    Technion Israel Institute Technology, Israel.
    Microstructure of ZnO films synthesized on MgAl2O4 from low-temperature aqueous solution: growth and post-annealing2013In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 48, no 4, p. 1614-1622Article in journal (Refereed)
    Abstract [en]

    The microstructure of ZnO films synthesized from low-temperature (90 degrees C) aqueous solution on (111) MgAl2O4 single crystal substrates was characterized by X-ray diffraction, high-resolution scanning electron microscopy, conventional and high-resolution transmission electron microscopy. To examine the thermally activated microstructural evolution of the ZnO, both as-deposited and annealed films were characterized. The ZnO films were confirmed to have a ZnO[10 (1) over bar0](0001)parallel to MgAl2O4[011](1 (1) over bar1) orientation relationship, with Zn polarity normal to the surface. Despite their highly oriented nature, the ZnO films have a columnar grain structure with low-angle (less than2.5 degrees) grain boundaries. In addition to lattice dislocations forming low-angle grain boundaries, threading dislocations were observed, emanating from the interface with the substrate. In annealed films, thermally generated voids were observed and appeared to preferentially form at grain boundaries and dislocations. Based on these characterization results, mechanisms are proposed for film growth and microstructural evolution. Finally, the diffusion coefficient of vacancies via dislocations at grain boundaries in the produced ZnO films was estimated.

  • 16.
    Nygren, Kristian
    et al.
    Uppsala University, Sweden; Impact Coatings AB, Westmansgatan 29, S-58216 Linkoping, Sweden.
    Mikaela Andersson, Anna
    ABB Corp Research, Sweden.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Jansson, Ulf
    Uppsala University, Sweden.
    Passive films on nanocomposite carbide coatings for electrical contact applications2017In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 52, no 13, p. 8231-8246Article in journal (Refereed)
    Abstract [en]

    Nanocomposite transition metal carbide/amorphous carbon coatings (Me-C/a-C) deposited by magnetron sputtering have excellent electrical contact properties. The contact resistance can be as low as that of noble metal coatings, although it is known to vary by several orders of magnitude depending on the deposition conditions. We have investigated a nanocrystalline niobium carbide/amorphous carbon (NbC (x) /a-C:H) model system aiming to clarify factors affecting the contact resistance for this group of contact materials. For the first time, the surface chemistry is systematically studied, by angle-resolved X-ray photoelectron spectroscopy, and in extension how it can explain the contact resistance. The coatings presented a mean oxide thickness of about 1 nm, which could be grown to 8 nm by annealing. Remarkably, the contact resistances covered four orders of magnitude and were found to be exponentially dependent on the mean oxide thickness. Moreover, there is an optimum in the amount of a-C:H phase where the contact resistance drops very significantly and it is thus important to not only consider the mean oxide thickness. To explain the results, a model relying on surface chemistry and contact mechanics is presented. The lowest contact resistance of a nanocomposite matched that of a gold coating at 1 N load (vs. gold), and such performance has previously not been demonstrated for similar nanocomposite materials, highlighting their useful properties for electrical contact applications.

  • 17.
    Petruhins, Andrejs
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Ingason, Arni Sigurdur
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Magnus, Fridrik
    Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden.
    Olafsson, Sveinn
    Science Institute, University of Iceland, Reykjavik, Iceland.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Synthesis and characterization of magnetic (Cr0.5Mn0.5)2GaC thin films2015In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 50, no 13, p. 4495-4502Article in journal (Refereed)
    Abstract [en]

    Growth of (Cr0.5Mn0.5)2GaC thin films from C, Ga, and compound Cr0.5Mn0.5 targets is reported for depositions on MgO (111), 4H-SiC (0001), and Al2O3 (0001) with and without a NbN (111) seed layer. Structural quality is found to be highly dependent on the choice of substrate with MgO (111) giving the best results as confirmed by X-ray diffraction and transmission electron microscopy. Phase pure, high crystal quality MAX phase thin films are realized, with a Cr:Mn ratio of 1:1. Vibrating sample magnetometry shows a ferromagnetic component from 30 K up to 300 K, with a measured net magnetic moment of 0.67 μB per metal (Cr + Mn) atom at 30 K and 5 T. The temperature dependence of the magnetic response suggests competing magnetic interactions with a resulting non-collinear magnetic ordering.

  • 18.
    Schmidt, Susann
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. European Spallat Source ERIC, Sweden.
    Höglund, Carina
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. European Spallat Source ERIC, Sweden.
    Jensen, Jens
    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.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hall-Wilton, Richard
    European Spallat Source ERIC, Sweden; Mid Sweden University, Sweden.
    Low-temperature growth of boron carbide coatings by direct current magnetron sputtering and high-power impulse magnetron sputtering2016In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 51, no 23, p. 10418-10428Article in journal (Refereed)
    Abstract [en]

    B4C coatings for B-10-based neutron detector applications were deposited using high-power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (DCMS) processes. The coatings were deposited on Si(001) as well as on flat and macrostructured (grooved) Al blades in an industrial coating unit using B4C compound targets in Ar. The HiPIMS and DCMS processes were conducted at substrate temperatures of 100 and 400 A degrees C and the Ar pressure was varied between 300 and 800 mPa. Neutron detector-relevant coating characterization was performed and the coating properties were evaluated with regard to their growth rate, density, level of impurities, and residual coating stress. The coating properties are mainly influenced by general process parameters such as the Ar pressure and substrate temperature. The deposition mode shows only minor effects on the coating quality and no effects on the step coverage. At a substrate temperature of 100 A degrees C and an Ar pressure of 800 mPa, well-adhering and functional coatings were deposited in both deposition modes; the coatings showed a density of 2.2 g/cm(3), a B/C ratio of similar to 3.9, and the lowest compressive residual stresses of 180 MPa. The best coating quality was obtained in DCMS mode using an Ar pressure of 300 mPa and a substrate temperature of 400 A degrees C. Such process parameters yielded coatings with a slightly higher density of 2.3 g/cm(3), a B/C ratio of similar to 4, and the compressive residual stresses limited to 220 MPa.

  • 19.
    Schroeder, Jeremy
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Saha, Bivas
    Purdue University, IN 47907 USA; Purdue University, IN 47907 USA.
    Garbrecht, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Schell, Norbert
    Helmholtz Zentrum Geesthacht, Germany.
    Sands, Timothy D.
    Virginia Tech, VA 24061 USA; Virginia Tech, VA 24061 USA.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Thermal stability of epitaxial cubic-TiN/(Al,Sc)N metal/semiconductor superlattices2015In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 50, no 8, p. 3200-3206Article in journal (Refereed)
    Abstract [en]

    We report on the thermal stability of epitaxial cubic-TiN/(Al,Sc)N metal/semiconductor superlattices with the rocksalt crystal structure for potential plasmonic, thermoelectric, and hard coating applications. TiN/Al0.72Sc0.28N superlattices were annealed at 950 and 1050 A degrees C for 4, 24, and 120 h, and the thermal stability was characterized by high-energy synchrotron-radiation-based 2D X-ray diffraction, high-resolution (scanning) transmission electron microscopy [HR(S)/TEM], and energy dispersive X-ray spectroscopy (EDX) mapping. The TiN/Al0.72Sc0.28N superlattices were nominally stable for up to 4 h at both 950 and 1050 A degrees C. Further annealing treatments for 24 and 120 h at 950 A degrees C led to severe interdiffusion between the layers and the metastable cubic-Al0.72Sc0.28N layers partially transformed into Al-deficient cubic-(Al,Sc)N and the thermodynamically stable hexagonal wurtzite phase with a nominal composition of AlN (h-AlN). The h-AlN grains displayed two epitaxial variants with respect to c-TiN and cubic-(Al,Sc)N. EDX mapping suggests that scandium has a higher tendency for diffusion in TiN/(Al,Sc)N than titanium or aluminum. Our results indicate that the kinetics of interdiffusion and the cubic-to-hexagonal phase transformation place constraints on the design and implementation of TiN/(Al,Sc)N superlattices for high-temperature applications.

  • 20.
    Sonestedt, Marie
    et al.
    Chalmers.
    Frodelius, Jenny
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Palmquist, Jens-Petter
    Kanthal AB.
    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.
    Stiller, Krystyna
    Chalmers.
    Microstructure of high velocity oxy-fuel sprayed Ti2AlC coatings2010In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 45, no 10, p. 2760-2769Article in journal (Refereed)
    Abstract [en]

    The microstructure formation and phase transformations in Ti2AlC-rich coatings deposited by High Velocity Oxy-fuel spraying of Maxthal 211(A (R)) powders is presented. High resolution electron microscopy analysis, using both scanning and transmission electron microscopy with energy dispersive spectrometry and energy filtering, combined with X-ray diffraction reveals that the coatings consist of Ti2AlC grains surrounded by regions of very small TiC grains embedded in Ti (x) Al (y) . The composition of the Ti (x) Al (y) depends on its surrounding and varies with size and distribution of the adjacent TiC grains. Impact of spray parameters on coating microstructure is also discussed. Two spray parameters were varied; powder size distribution and flame power. They were found to greatly affect the coating microstructure. Increasing powder size and decreasing flame power increase the amount of Ti2AlC, but produces thinner coatings with lower cohesion. Larger powder size will also decrease oxygen incorporation.

  • 21.
    Sun, Bing
    et al.
    Uppsala University, Sweden .
    Tehrani, Payman
    Inorel AB, Sweden .
    Robinson, Nathaniel D.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology. Inorel AB, Sweden .
    Brandell, Daniel
    Uppsala University, Sweden .
    Tailoring the conductivity of PEO-based electrolytes for temperature-sensitive printed electronics2013In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 48, no 17, p. 5756-5767Article in journal (Refereed)
    Abstract [en]

    This study reports an approach to tailoring the temperature-sensitive conductivity behavior of poly(ethylene oxide) (PEO)-based polymer electrolytes to match a concrete hardening model, for use in temperature-sensitive organic electronics. Plasticized PEO/MX (M = Li, Na; X = TFSI, Tf) polymer electrolytes were designed to fit a specific temperature-sensitive behavior of the ionic conductivity within a temperature range of 20-60 A degrees C. Polymer electrolytes with varying concentrations of plasticizing solvents (propylene carbonate and ethylene carbonate; PC and EC) and short-chain polyether homologs such as poly(ethylene glycol)-dimethyl ether were produced. Some of the investigated electrolytes displayed useful and stable temperature-sensitive conductivity for applications in process monitoring or quality control of temperature-sensitive products; the best being either a 40:60 PEO:PEGDME blend by w/w containing NaCF3SO3 at a Na:O ratio 1:10 and with 10 wt% PC or PEO with LiTFSI or NaTFSI at a salt:O ratio 1:25 and 30 wt% PC. Analysis of variance indicates the adequacy of temperature-sensitive poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) electrochromic monitoring devices based on these electrolytes relative to a standard model for the concrete hardening process.

  • 22.
    Wang, Lei
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Solin, Niclas
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Preparation of functionalized protein materials assisted by mechanochemistry2018In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 53, no 19, p. 13719-13732Article in journal (Refereed)
    Abstract [en]

    Herein, we investigate the suitability of hen egg-white lysozyme (HEWL) as a protein matrix for dispersal of various hydrophobic dyes. Moreover, we investigate the use of a mixer mill for grinding operation as an alternative to hand grinding by mortar and pestle. HEWL and various dyes are mixed by mechanochemistry, and the resulting composite material is dissolved in aqueous acid. The samples are then exposed to conditions promoting self-assembly of HEWL into protein nanofibrils (PNFs). The effect of PNF formation on dye photophysics is investigated by spectroscopic examination by absorption and luminescence spectroscopy, and product morphology is examined by scanning electron microscopy. The self-assembly process results in protein nanofibrils functionalized with luminescent dyes. Such structures may find future applications in various devices for light emission. In addition, we demonstrate that the anticancer drug camptothecin can be incorporated into protein nanofibrils giving materials that can find application as drug delivery agents.

  • 23.
    Xi, Wenjun
    et al.
    School of Materials Science and Engineeering, Beihang Univeristy, Beijing, China.
    Peng, Ru
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, The Institute of Technology.
    Wu, Wei
    School of Materials Science and Engineeering, Beihang Univeristy, Beijing, China.
    Li, Neng
    School of Materials Science and Engineeering, Beihang Univeristy, Beijing, China.
    Wang, Shubin
    School of Materials Science and Engineeering, Beihang Univeristy, Beijing, China.
    Johansson, Sten
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, The Institute of Technology.
    Al2O2 Nanoparticle Reinforced Fe-based Alloys Synthesized by Thermite Reaction2012In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 47, no 8, p. 3585-3591Article in journal (Refereed)
    Abstract [en]

    It is very difficult to manufacture oxide nanoparticle strengthened alloys through the conventional casting in the gravity field or even in the space microgravity environment. A thermite reaction process was used to produce molten metal that was then solidified in a graphite mold in super gravity field caused by centrifugal force; we were able to obtain Al2O3 nanoparticle reinforced Fe-based alloys. The formation of Al2O3 nanoparticles was related to the addition of TiO2 xerogel to the thermite mixture, and their uniform distribution in the alloy can be explained by their assembly in (Ni, Fe)Al intermetallics during solidification owing to the low interfacial energy between them.

  • 24.
    Yao, Y.
    et al.
    Materials and Manufacturing Technology, Chalmers University of Technology, Gothenburg 412 96, Sweden.
    Janis, A.
    Jänis, A., Division of Sensor Systems, Swedish Defence Research Agency, Linkoping 581 11, Sweden.
    Klement, U.
    Materials and Manufacturing Technology, Chalmers University of Technology, Gothenburg 412 96, Sweden.
    Characterization and dielectric properties of ß-SiC nanofibres2008In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 43, no 3, p. 1094-1101Article in journal (Refereed)
    Abstract [en]

    SiC nanofibres produced by chemical vapour reaction technique are investigated using scanning and transmission electron microscopy. The nanofibres have been found to have a crystalline core of ß-SiC sheathed with thorn-like turbostratic carbon or amorphous Si/O/C, respectively. For this material, real and imaginary part of relative permittivity is measured in a frequency range of 1-18 GHz at room temperature. The results reveal that the permittivity and dielectric loss in the SiC nanofibres are a magnitude higher compared with sub-microcrystalline SiC powder. Composition and nanostructure are held responsible for the difference in dielectric properties. The mechanisms of dielectric loss in the SiC nanofibres are discussed based on interfacial polarization, lattice defects in the SiC nanofibre cores and conduction loss of turbostratic carbon in the thorn-like sheath of SiC nanofibres. © 2007 Springer Science+Business Media, LLC.

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