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  • 51.
    Gabrysch, Markus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Marklund, Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi, Molekylär biofysik.
    Hajdu, Janos
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi, Molekylär biofysik.
    Twitchen, D. J.
    Element Six Ltd, Ascot SL5 8BP, Berks, England.
    Rudati, J.
    Stanford Linear Accelerator Ctr, PULSE Ctr, Menlo Pk, CA 94025 USA.
    Lindenberg, A. M.
    Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA; PULSE Center, Stanford Linear Accelerator Center, Menlo Park, California 94025, USA.
    Caleman, Carl
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi, Molekylär biofysik.
    Falcone, R. W.
    Department of Physics, University of California, Berkeley, California 94720, USA.
    Tschentscher, T.
    Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany.
    Moffat, K.
    Consortium for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, USA.
    Bucksbaum, P. H.
    PULSE Center, Stanford Linear Accelerator Center, Menlo Park, California 94025, USA.
    Als-Nielsen, J.
    Niels Bohr Institute, Copenhagen University, 2100 Copenhagen Ø, Denmark.
    Nelson, A. J.
    Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
    Siddons, D. P.
    National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973, USA.
    Emma, P. J.
    Stanford Linear Accelerator Ctr, PULSE Ctr, Menlo Pk, CA 94025 USA.
    Krejcik, P.
    Stanford Linear Accelerator Ctr, PULSE Ctr, Menlo Pk, CA 94025 USA.
    Schlarb, H.
    Stanford Linear Accelerator Ctr, PULSE Ctr, Menlo Pk, CA 94025 USA.
    Arthur, J.
    Stanford Linear Accelerator Ctr, PULSE Ctr, Menlo Pk, CA 94025 USA.
    Brennan, S.
    Stanford Linear Accelerator Ctr, PULSE Ctr, Menlo Pk, CA 94025 USA.
    Hastings, J.
    Stanford Linear Accelerator Ctr, PULSE Ctr, Menlo Pk, CA 94025 USA.
    Isberg, Jan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Formation of secondary electron cascades in single-crystalline plasma-deposited diamond upon exposure to femtosecond x-ray pulses2008Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 103, nr 6, artikel-id 064909Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Secondary electron cascades were measured in high purity single-crystalline chemical vapor deposition (CVD) diamond, following exposure to ultrashort hard x-ray pulses (140 fs full width at half maximum, 8.9 keV energy) from the Sub-Picosecond Pulse Source at the Stanford Linear Accelerator Center. We report measurements of the pair creation energy and of drift mobility of carriers in two CVD diamond crystals. This was done for the first time using femtosecond x-ray excitation. Values for the average pair creation energy were found to be 12.17 +/- 0.57 and 11.81 +/- 0.59 eV for the two crystals, respectively. These values are in good agreement with recent theoretical predictions. The average drift mobility of carriers, obtained by the best fit to device simulations, was mu(h)= 2750 cm(2)/V s for holes and was mu(e)= 2760 cm(2) / V s for electrons. These mobility values represent lower bounds for charge mobilities due to possible polarization of the samples. The results demonstrate outstanding electric properties and the enormous potential of diamond in ultrafast x-ray detectors.

  • 52. Ganguli, Nirmal
    et al.
    Dasgupta, Indra
    Sanyal, Biplab
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Electronic structure and magnetism of transition metal doped Zn12O12 clusters: Role of defects2010Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 108, nr 12, s. 123911-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present a comprehensive study of the energetics and magnetic properties of ZnO clusters doped with 3d transition metals (TMs) using ab initio density functional calculations in the framework of generalized gradient approximation + Hubbard U (GGA+U) method. Our results within GGA+U for all 3d dopants except Ti indicate that antiferromagnetic interaction dominates in a neutral, defect-free cluster. Formation energies are calculated to identify the stable defects in the ZnO cluster. We have analyzed in details the role of these defects to stabilize ferromagnetism when the cluster is doped with Mn, Fe, and Co. Our calculations reveal that in the presence of charged defects the TM atoms residing at the surface of the cluster may have an unusual oxidation state, that plays an important role to render the cluster ferromagnetic. Defect induced magnetism in ZnO clusters without any TM dopants is also analyzed. These results on ZnO clusters may have significant contributions in the nanoengineering of defects to achieve desired ferromagnetic properties for spintronic applications.

  • 53. Girt, Erol
    et al.
    Huttema, W.
    Mryasov, O. N.
    Montoya, E.
    Kardasz, B.
    Eyrich, C.
    Heinrich, B.
    Dobin, A. Yu.
    Karis, Olof
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Yt- och gränsskiktsvetenskap.
    A method for measuring exchange stiffness in ferromagnetic films2011Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 109, nr 7, s. 07B765-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An exchange stiffness, A(ex), in ferromagnetic films is obtained by fitting the M(H) dependence of two ferromagnetic layers antiferromagnetically coupled across a nonmagnetic spacer layer with a simple micromagnetic model. In epitaxial and textured structures this method allows measuring A(ex) between the crystallographic planes perpendicular to the growth direction of ferromagnetic films. Our results show that A(ex) between [0001] planes in textured Co grains is 1.54 +/- 0.12 x 10(-11) J/m.

  • 54. Goncharov, Alexander F.
    et al.
    Wong, Michael
    Dalton, D. Allen
    Ojwang, J. G. O.
    Struzhkin, Viktor V.
    Konopkova, Zuzana
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Berggrundsgeologi.
    Lazor, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Berggrundsgeologi.
    Thermal conductivity of argon at high pressures and high temperatures2012Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 111, nr 11, s. 112609-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Knowledge of the thermal conductivity of Ar under conditions of high pressures and temperatures (P-T) is important for model calculations of heat transfer in the laser heated diamond anvil cell (DAC) as it is commonly used as a pressure transmitting medium and for thermal insulation. We used a modified transient heating technique utilizing microsecond laser pulses in a symmetric DAC to determine the P-T dependent thermal conductivity of solid Ar up to 50 GPa and 2500 K. The temperature dependent thermal conductivity of Ar was obtained by fitting the results of finite element calculations to the experimentally determined time dependent temperature of a thin Ir foil surrounded by Ar. Our data for the thermal conductivity of Ar are larger than that theoretically calculated using the Green-Kubo formalism, but they agree well with those based on kinetic theory. These results are important for ongoing studies of the thermal transport properties of minerals at pressures and temperatures native to the mantle and core.

  • 55.
    GRANBERG, P
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    NORDBLAD, P
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    SVEDLINDH, P
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    LUNDGREN, L
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    STUBI, R
    KENNING, GG
    LESLIEPELECKY, DL
    BASS, J
    COWEN, J
    DIMENSIONALITY CROSSOVER IN CUMN SPIN-GLASS FILMS1990Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 67, s. 5252-5254Artikel i tidskrift (Refereegranskat)
  • 56.
    Greczynski, G.
    et al.
    Linkoping Univ, Dept Phys IFM, Thin Film Phys Div, SE-58183 Linkoping, Sweden.;Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Mraz, S.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Hans, M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Primetzhofer, Daniel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Tillämpad kärnfysik.
    Lu, J.
    Linkoping Univ, Dept Phys IFM, Thin Film Phys Div, SE-58183 Linkoping, Sweden..
    Hultman, L.
    Linkoping Univ, Dept Phys IFM, Thin Film Phys Div, SE-58183 Linkoping, Sweden..
    Schneider, J. M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Unprecedented Al supersaturation in single-phase rock salt structure VAlN films by Al+ subplantation2017Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 121, nr 17, artikel-id 171907Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Modern applications of refractory ceramic thin films, predominantly as wear-protective coatings on cutting tools and on components utilized in automotive engines, require a combination of excellent mechanical properties, thermal stability, and oxidation resistance. Conventional design approaches for transition metal nitride coatings with improved thermal and chemical stability are based on alloying with Al. It is well known that the solubility of Al in NaCl-structure transition metal nitrides is limited. Hence, the great challenge is to increase the Al concentration substantially while avoiding precipitation of the thermodynamically favored wurtzite-AlN phase, which is detrimental to mechanical properties. Here, we use VAlN as a model system to illustrate a new concept for the synthesis of metastable single-phase NaCl-structure thin films with the Al content far beyond solubility limits obtained with conventional plasma processes. This supersaturation is achieved by separating the film-forming species in time and energy domains through synchronization of the 70-mu s-long pulsed substrate bias with intense periodic fluxes of energetic Al+ metal ions during reactive hybrid high power impulse magnetron sputtering of the Al target and direct current magnetron sputtering of the V target in the Ar/N-2 gas mixture. Hereby, Al is subplanted into the cubic VN grains formed by the continuous flux of low-energy V neutrals. We show that Al subplantation enables an unprecedented 42% increase in metastable Al solubility limit in V1-xAlxN, from x-0.52 obtained with the conventional method to 0.75. The elastic modulus is 325 +/- 5GPa, in excellent agreement with density functional theory calculations, and approximately 50% higher than for corresponding films grown by dc magnetron sputtering. The extension of the presented strategy to other Al-ion-assisted vapor deposition methods or materials systems is straightforward, which opens up the way for producing supersaturated single-phase functional ceramic alloy thin films combining excellent mechanical properties with high oxidation resistance.

  • 57.
    Hai, Ling
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Svensson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Isberg, Jan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Leijon, Mats
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära. Univ Southampton, Energy & Climate Change Div, Fac Engn & Environm, Southampton, Hants, England.
    Modelling a point absorbing wave energy converter by the equivalent electric circuit theory: A feasibility study2015Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 117, artikel-id 164901Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There is a need to have a reliable tool to quickly assess wave energy converters (WECs). This paper explores whether it is possible to apply the equivalent electric circuit theory as an evaluation tool for point absorbing WEC system modelling. The circuits were developed starting from the force analysis, in which the hydrodynamic, mechanical, and electrical parameters were expressed by electrical components. A methodology on how to determine the parameters for electrical components has been explained. It is found that by using a multimeter, forces in the connection line and the absorbed electric power can be simulated and read directly from the electric circuit model. Finally, the circuit model has been validated against the full scale offshore experiment. The results indicated that the captured power could be predicted rather accurately and the line force could be estimated accurately near the designed working condition of the WEC.

  • 58. Hallén, A
    et al.
    Paska, Z
    Rosling, M
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Sundqvist, BUR
    Svensson, BG
    Tirén, J
    Deep level transient spectroscopy analysis of fast ion tracks in silicon1990Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 67, nr 3, s. 1266-1271Artikel i tidskrift (Refereegranskat)
  • 59. Hans, M.
    et al.
    Baben, M. To
    Music, D.
    Ebenhoech, J.
    Primetzhofer, Daniel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Tillämpad kärnfysik.
    Kurapov, D.
    Arndt, M.
    Rudigier, H.
    Schneider, J. M.
    Effect of oxygen incorporation on the structure and elasticity of Ti-Al-O-N coatings synthesized by cathodic arc and high power pulsed magnetron sputtering2014Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 116, nr 9, s. 093515-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ti-Al-O-N coatings were synthesized by cathodic arc and high power pulsed magnetron sputtering. The chemical composition of the coatings was determined by means of elastic recoil detection analysis and energy dispersive X-ray spectroscopy. The effect of oxygen incorporation on the stress-free lattice parameters and Young's moduli of Ti-Al-O-N coatings was investigated by X-ray diffraction and nanoindentation, respectively. As nitrogen is substituted by oxygen, implications for the charge balance may be expected. A reduction in equilibrium volume with increasing O concentration is identified by X-ray diffraction and density functional theory calculations of Ti-Al-O-N supercells reveal the concomitant formation of metal vacancies. Hence, the oxygen incorporation-induced formation of metal vacancies enables charge balancing. Furthermore, nanoindentation experiments reveal a decrease in elastic modulus with increasing O concentration. Based on ab initio data, two causes can be identified for this: First, the metal vacancy-induced reduction in elasticity; and second, the formation of, compared to the corresponding metal nitride bonds, relatively weak Ti-O and Al-O bonds.

  • 60.
    Hirt, Ann M.
    et al.
    ETH, Dept Earth Sci, Inst Geophys, CH-8092 Zurich, Switzerland..
    Sotiriou, Georgios A.
    ETH, Dept Mech & Proc Engn, Inst Proc Engn, Particle Technol Lab, CH-8092 Zurich, Switzerland.;Harvard Univ, Dept Environm Hlth, Boston, MA 02115 USA..
    Kidambi, Piran R.
    ETH, Dept Mech & Proc Engn, Inst Proc Engn, Particle Technol Lab, CH-8092 Zurich, Switzerland.;Univ Cambridge, Dept Engn, Cambridge CB3 0FA, England..
    Teleki, Alexandra
    ETH, Dept Mech & Proc Engn, Inst Proc Engn, Particle Technol Lab, CH-8092 Zurich, Switzerland.;DSM Nutr Prod Ltd, CH-4002 Basel, Switzerland..
    Effect of size, composition, and morphology on magnetic performance: First-order reversal curves evaluation of iron oxide nanoparticles2014Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 115, nr 4, artikel-id 044314Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Superparamagnetic nanoparticles are employed in a broad range of applications that demand detailed magnetic characterization for superior performance, e. g., in drug delivery or cancer treatment. Magnetic hysteresis measurements provide information on saturation magnetization and coercive force for bulk material but can be equivocal for particles having a broad size distribution. Here, first-order reversal curves (FORCs) are used to evaluate the effective magnetic particle size and interaction between equally sized magnetic iron oxide (Fe2O3) nanoparticles with three different morphologies: (i) pure Fe2O3, (ii) Janus-like, and (iii) core/shell Fe2O3/SiO2 synthesized using flame technology. By characterizing the distribution in coercive force and interaction field from the FORC diagrams, we find that the presence of SiO2 in the core/shell structures significantly reduces the average coercive force in comparison to the Janus-like Fe2O3/SiO2 and pure Fe2O3 particles. This is attributed to the reduction in the dipolar interaction between particles, which in turn reduces the effective magnetic particle size. Hence, FORC analysis allows for a finer distinction between equally sized Fe2O3 particles with similar magnetic hysteresis curves that can significantly influence the final nanoparticle performance. (C) 2014 AIP Publishing LLC.

  • 61. Hu, Qing-Miao
    et al.
    Kádas, Krisztina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen, Kondenserade materiens teori (Fysik IV).
    Hogmark, Sture
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Yang, Rui
    Johansson, Börje
    Vitos, Levente
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen, Kondenserade materiens teori (Fysik IV).
    Hardness and elastic properties of covalent/ionic solid solutions from first-principles theory2008Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 103, nr 8, s. 083505-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Most of the engineering materials are alloys (solid solutions) and inevitably contain some impurities or defects such as vacancies. However, theoretical predictions of the hardness of this kind of materials have rarely been addressed in literature. In this paper, a hardness formula for multicomponent covalent solid solution is proposed based on the work of Simunek and Vackar [Phys. Rev. Lett. 96, 085501 (2006)]. With this formula, the composition dependence of the hardness is investigated for titanium nitrogencarbide (TiN1-xCx), off-stoichiometric transition-metal nitrides (TiN1-x and VN1-x), and B-doped semiconductors. The predicted hardness is in good agreement with experiments. To investigate the most frequently quoted correlation between hardness and elastic modulus, the elastic moduli of the systems involved in this paper have also been calculated. The results show that the elastic moduli cannot be used for rigorous predictions of the hardness of the solid solutions.

  • 62. HUDNER, J
    et al.
    OSTLING, M
    OHLSEN, H
    STOLT, L
    NORDBLAD, P
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    OTTOSSON, M
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    VILLEGIER, JC
    MORICEAU, H
    WEISS, F
    THOMAS, O
    PREPARATION OF YBA2CU3O7-X FILMS AND YBA2CU3O7-X/Y2O3 MULTILAYERS USING COEVAPORATION AND ATOMIC OXYGEN1993Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 73, s. 3096-3098Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thin layers of YBa2Cu3O7-x (YBCO) deposited on LaAlO3 substrates have been prepared in situ by coevaporation of Y, Ba, and Cu. Incorporation of oxygen was accomplished by an atomic oxygen beam source with high cracking efficiency. The total oxygen flow at the substrate could be kept low enough to permit the use of a quadrupole mass spectrometer for evaporation rate monitoring. Films were strongly c-axis oriented with rocking curve full width at half-maximum values of 0.6-degrees. Transport measurements on patterned films yielded critical current densities of 6 x 10(6) A/cm2 at 77 K. The deposition method was demonstrated to be feasible for preparation of Y2O3/YBCO heterostructures.

  • 63.
    Hultqvist, Adam
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Salomé, Pedro M. P.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Fjällström, Viktor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Edoff, Marika
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Aitken, B.
    Zhang, K.
    Shi, Y.
    Fuller, K.
    Williams, C. Kosik
    Performance of Cu(In,Ga)Se-2 solar cells using nominally alkali free glass substrates with varying coefficient of thermal expansion2013Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 114, nr 9, s. 094501-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this report, Cu(In,Ga)Se-2, CIGS, solar cell devices have been fabricated on nominally alkali free glasses with varying coefficients of thermal expansion (CTE) from 50 to 95* 10(-7)/degrees C. A layer of NaF deposited on top of the Mo was used to provide Na to the CIGS film. Increasing the glass CTE leads to a change of stress state of the solar cell stack as evidenced by measured changes of stress state of the Mo layer after CIGS deposition. The open circuit voltage, the short circuit current density, and the fill factors, for solar cells made on the various substrates, are all found to increase with CTE to a certain point. The median energy conversion efficiency values for 32 solar cells increases from 14.6% to the lowest CTE glass to 16.5% and 16.6%, respectively, for the two highest CTE glasses, which have CTE values closest to that of the soda lime glass. This is only slightly lower than the 17.0% median of soda lime glass reference devices. We propose a model where an increased defect density in the CIGS layer caused by thermal mismatch during cool-down is responsible for the lower efficiency for the low CTE glass substrates.

  • 64.
    Hunold, Oliver
    et al.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Chen, Yen-Ting
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Music, Denis
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Persson, Per O. A.
    Linkoping Univ, Dept Phys Chem & Biol IFM, S-58183 Linkoping, Sweden..
    Primetzhofer, Daniel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Tillämpad kärnfysik.
    Baben, Moritz
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Achenbach, Jan-Ole
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Keuter, Philipp
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Schneider, Jochen M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Correlative theoretical and experimental investigation of the formation of AIYB(14) and competing phases2016Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 119, nr 8, artikel-id 085307Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The phase formation in the boron-rich section of the Al-Y-B system has been explored by a correlative theoretical and experimental research approach. The structure of coatings deposited via high power pulsed magnetron sputtering from a compound target was studied using elastic recoil detection analysis, electron energy loss spectroscopy spectrum imaging, as well as X-ray and electron diffraction data. The formation of AlYB14 together with the (Y,Al)B-6 impurity phase, containing 1.8 at. % less B than AlYB14, was observed at a growth temperature of 800 degrees C and hence 600 degrees C below the bulk synthesis temperature. Based on quantum mechanical calculations, we infer that minute compositional variations within the film may be responsible for the formation of both icosahedrally bonded AlYB14 and cubic (Y,Al)B-6 phases. These findings are relevant for synthesis attempts of all boron rich icosahedrally bonded compounds with the space group: Imma that form ternary phases at similar compositions.

  • 65. Intarasiri, Saweat
    et al.
    Yu, L.D.
    Singkarat, S.
    Hallén, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Jonfysik.
    Lu, Jun
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Ottosson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi.
    Jensen, Jens
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Jonfysik.
    Possnert, Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Jonfysik.
    Effects of low-fluence swift iodine ion bombardment on the crystallization of ion-beam-synthesized silicon carbide2007Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 101, nr 8, s. 084311-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ion beam synthesis using high-fluence carbon ion implantation in silicon in combination with subsequent or in situ thermal annealing has been shown to be able to form nanocrystalline cubic SiC (3C-SiC) layers in silicon. In this study, a silicon carbide layer was synthesized by 40-keV C 12 + implantation of a p -type (100) Si wafer at a fluence of 6.5× 1017 ions cm2 at an elevated temperature. The existence of the implanted carbon in Si substrate was investigated by time-of-flight energy elastic recoil detection analysis. The SiC layer was subsequently irradiated by 10-30 MeV I 127 ions to a very low fluence of 1012 ions cm2 at temperatures from 80 to 800 °C to study the effect on the crystallization of the SiC layer. Infrared spectroscopy and Raman scattering measurement were used to monitor the formation of SiC and detailed information about the SiC film properties was obtained by analyzing the peak shape of the Si-C stretching mode absorption. The change in crystallinity of the synthesized layer was probed by glancing incidence x-ray diffraction measurement and transmission electron microscopy was also used to confirm the results and to model the crystallization process. The results from all these measurements showed in a coherent way that the synthesized structure was a polycrystalline layer with nanometer sized SiC crystals buried in a-Si matrix. The crystallinity of the SiC layer was enhanced by the low-fluence swift heavy ion bombardment and also favored by higher energy, higher fluence, and higher substrate temperature. It is suggested that electronic stopping plays a dominant role in the enhancement.

  • 66.
    Isaev, Eyvaz I.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Simak, S. I.
    Abrikosov, I. A.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Vekilov, Yu. Kh.
    Katsnelson, M. I.
    Lichtenstein, A. I.
    Johansson, Börje
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Phonon related properties of transition metals, their carbides, and nitrides: A first-principles study2007Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 101, nr 12, s. 123519-Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Lattice dynamics of body-centered cubic (bcc) V-b-VIb group transition metals (TM), and B1-type monocarbides and mononitrides of IIIb-VIb transition metals are studied by means of first-principles density functional perturbation theory, ultra soft pseudopotentials, and generalized gradient approximation to the exchange-correlation functional. Ground state parameters of transition metals and their compounds are correctly reproduced with the generated ultrasoft pseudopotentials. The calculated phonon spectra of the bcc metals are in excellent agreement with results of inelastic neutron scattering experiments. We show that the superconductivity of transition metal carbides (TMC) and transition metal nitrides (TMN) is related to peculiarities of the phonon spectra, and the anomalies of the spectra are connected to the number of valence electrons in crystals. The calculated electron-phonon interaction constants for TM, TMC, and TMN are in excellent agreement with experimentally determined values. Phonon spectra for a number of monocarbides and mononitrides of transition metals within the cubic NaCl- and hexagonal WC-type structures are predicted. Ideal stoichiometric B1 crystals of ScC, YC, and VC are predicted to be dynamically stable and superconducting materials. We also conclude that YN is a semiconductor.

  • 67.
    Iusan, Diana
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Sanyal, Biplab
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Eriksson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Influence of defects on the magnetism of Mn-doped ZnO2007Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 101, nr 9, s. 09H101-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The properties of dilute magnetic semiconductors are usually strongly influenced by the defects present in the system. Ab initio calculations may provide valuable insight for the microscopic understanding of the interactions with defects. Here, we present studies of Mn-doped ZnO in the presence of several defects by a combined approach of ab initio electronic structure calculations using Korringa-Kohn-Rostoker-coherent potential approximation and Monte Carlo simulations (MCSs). Electronic structure and magnetic interactions have similar trends for wurtzite and zinc-blende crystal structures. A weak antiferromagnetic interaction has been found for 5% Mn doping in defect-free ZnO. Defects such as O vacancies and Zn interstitials lead to antiferromagnetic interactions between the Mn atoms, while Zn vacancies and oxygen substitution by nitrogen yield ferromagnetic interactions. As the concentration of Mn is low and the exchange interactions are short ranged, MCSs show small values of Curie temperatures (not more than 50 K). However, for a few cases with codoping of Mn and defects, we obtained higher Curie temperatures (around 130 K). Estimates of the Curie temperatures, assuming an average separation of the Mn atoms in the mean-field solution of Heisenberg model, are in very good agreement with the results obtained from MCS.

  • 68. Jahnel, F
    et al.
    Biersack, J
    d'Heurle, F
    Fink, D
    Isaac, R
    Lucchese, C
    Petersson, CS
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    The behaviour of B (also As) in bilayers of polysilicon and SWi21982Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 53, s. 7372-Artikel i tidskrift (Refereegranskat)
  • 69.
    Johansson, Malin B.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Zietz, Burkhard
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Niklasson, Gunnar A
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Österlund, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Optical properties of nanocrystalline WO3 and WO3-x thin films prepared by DC magnetron sputtering2014Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 115, nr 21, s. 213510-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The optical properties of tungsten trioxide thin films prepared by DC magnetron sputtering, withdifferent oxygen vacancy (Vo) concentration, have been studied by spectrophotometry andphotoluminescence (PL) emission spectroscopy. Absorption and PL spectra show that the filmsexhibit similar band gap energies, Eg 2.9 eV. The absorption spectra of the films show twopronounced absorption bands in the near-infrared region. One peak (P1) is located atapproximately 0.7 eV, independent of Vo concentration. A second peak (P2) shifts from 0.96 eV to1.16 eV with decreasing Vo concentration. Peak P1 is assigned to polaron absorption due totransitions between tungsten sites (W5þ!W6þ), or an optical transition from a neutral vacancystate to the conduction band, Vo0!W6þ. The origin of peak P2 is more uncertain but may involveþ1 and þ2 charged vacancy sites. The PL spectra show several emission bands in the range 2.07 to3.10 eV in the more sub-stoichiometric and 2.40 to 3.02 eV in the less sub-stoichiometric films.The low energy emission bands agree well with calculated optical transition energies of oxygenvacancy sites, with dominant contribution from neutral and singly charged vacancies in the lesssub-stoichiometric films, and additional contributions from doubly charged vacancy sites in themore sub-stoichiometric films.

  • 70. Johansson, S
    et al.
    Schweitz, J-Å
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Tenerz, L
    Tirén, J
    Fracture testing of silicon microelements in situ in a scanning electron microscope1988Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 63, nr 10Artikel i tidskrift (Refereegranskat)
  • 71.
    Josefsson, Gabriella
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Ahvenainen, Patrik
    Department of Physics, University of Helsinki, Helsinki, Finland.
    Ezekiel Mushic, Ngesa
    Department of Fibre and Polymer Technology and Wallenberg Wood Science Centre, Royal Institute of Technology (KTH).
    Gamstedt, Kristofer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Fibril orientation redistribution induced by stretching of cellulose nanofibril hydrogels2015Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 117, nr 21, artikel-id 214311Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The mechanical performance of materials reinforced by cellulose nanofibrils is highly affected by the orientation of these fibrils. This paper investigates the nanofibril orientation distribution of films of partly oriented cellulose nanofibrils. Stripes of hydrogel films were subjected to different amount of strain and, after drying, examined with X-ray diffraction to obtain the orientation of the nanofibrils in the films, caused by the stretching. The cellulose nanofibrils had initially a random in-plane orientation in the hydrogel films and the strain was applied to the films before the nanofibrils bond tightly together, which occurs during drying. The stretching resulted in a reorientation of the nanofibrils in the films, with monotonically increasing orientation towards the load direction with increasing strain. Estimation of nanofibril reorientation by X-ray diffraction enables quantitative comparison of the stretch-induced orientation ability of different cellulose nanofibril systems. The reorientation of nanofibrils as a consequence of an applied strain is also predicted by a geometrical model of deformation of nanofibril hydrogels. Conversely, in high-strain cold-drawing of wet cellulose nanofibril materials, the enhanced orientation is promoted by slipping of the effectively stiff fibrils.

  • 72.
    Kaewmaraya, Thanayut
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ramzan, Muhammad
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Löfås, Henrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Hybrid density functional study of electronic and optical properties of phase change memory material: Ge2Sb2Te52013Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 113, nr 3, s. 033510-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this article, we use hybrid density functional (HSE06) to study the crystal and electronic structures and optical properties of well known phase change memory material Ge2Sb2Te5. We calculate the structural parameters, band gaps, and dielectric functions of three stable structures of this material. We also analyze the electron charge distribution using the Bader's theory of charge analysis. We find that hybrid density functional slightly overestimates the value of "c" parameter. However, overall, our results calculated with the use of hybrid density functional (HSE06) are very close to available experimental values than calculated with the use of Perdew Burke-Ernzerhof functional. Specifically, the electronic band gap values of this material calculated with HSE06 are in good agreement with the available experimental data in the literature. Furthermore, we perform the charge analysis and find that naive ionic model fails to explain the charge distribution between the constituent atoms, showing the complex nature of this compound.

  • 73. Kapilashrami, M.
    et al.
    Conti, G.
    Zegkinoglou, I.
    Nemsak, S.
    Conlon, C. S.
    Törndahl, Tobias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Fjällström, Viktor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Lischner, J.
    Louie, Steven G.
    Hamers, R. J.
    Zhang, L.
    Guo, J. -H
    Fadley, C. S.
    Himpsel, F. J.
    Boron Doped diamond films as electron donors in photovoltaics: An X-ray absorption and hard X-ray photoemission study2014Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 116, nr 14, s. 143702-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Highly boron-doped diamond films are investigated for their potential as transparent electron donors in solar cells. Specifically, the valence band offset between a diamond film (as electron donor) and Cu(In,Ga)Se-2 (CIGS) as light absorber is determined by a combination of soft X-ray absorption spectroscopy and hard X-ray photoelectron spectroscopy, which is more depth-penetrating than standard soft X-ray photoelectron spectroscopy. In addition, a theoretical analysis of the valence band is performed, based on GW quasiparticle band calculations. The valence band offset is found to be small: VBO = VBMCIGS -VBMdiamond = 0.3 eV +/- 0.1 eV at the CIGS/Diamond interface and 0.0 eV +/- 0.1 eV from CIGS to bulk diamond. These results provide a promising starting point for optimizing the band offset by choosing absorber materials with a slightly lower valence band maximum. 

  • 74. Kazakova, Olga
    et al.
    Hansson, Maj
    Blixt, Anna Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Hjörvarsson, Björgvin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Magnetic properties of submicron permalloy elements: Effects of heat treatment2003Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 93, nr 10, s. 7334-7336Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present the results of the effect of annealing in hydrogen atmosphere on the magnetic properties of continuous magnetic films and patterned structures. Rectangular and elliptical particles, with lateral dimensions in the range 150–900 nm, were made of 24 and 66 nm thick permalloy films. The domain structure and the magnetization reversal processes were investigated by magnetic force microscopy and alternating gradient magnetometry. While the performed annealing at 200 °C during 48 h did not noticeably change the properties of the continuous films, it influenced the patterned structures significantly. The difference between patterned elements and the continuous films can be explained by enhanced relaxation and vacancy diffusion in the particles

  • 75.
    KING, AR
    et al.
    UCSB.
    BELANGER, DP
    UCSB.
    NORDBLAD, P
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    JACCARINO, V
    UCSB.
    CAPACITANCE MEASUREMENT OF MAGNETIC SPECIFIC-HEAT1984Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 55, s. 2410-2412Artikel i tidskrift (Refereegranskat)
  • 76. Kiran, M. S. R. N.
    et al.
    Tran, Tuan
    Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University, Canberra, Australia.
    Smillie, L. A.
    Haberl, B.
    Subianto, D.
    Williams, J.S.
    Bradby, J.E.
    Temperature-dependent mechanical deformation of silicon at the nanoscale: Phase transformation versus defect propagation2015Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 117, artikel-id 205901Artikel i tidskrift (Refereegranskat)
  • 77.
    Kiran, Mangalampalli
    et al.
    Canberra, Australien.
    Tran, Tuan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Tillämpad kärnfysik.
    Temperature-dependent mechanical deformation of silicon at the nanoscale: Phase transformation versus defect propagation2015Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 117, nr 20, s. 205901-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study uses high-temperature nanoindentation coupled with in situ electrical measurements to investigate the temperature dependence (25-200 degrees C) of the phase transformation behavior of diamond cubic (dc) silicon at the nanoscale. Along with in situ indentation and electrical data, ex situ characterizations, such as Raman and cross-sectional transmission electron microscopy, have been used to reveal the indentation-induced deformation mechanisms. We find that phase transformation and defect propagation within the crystal lattice are not mutually exclusive deformation processes at elevated temperature. Both can occur at temperatures up to 150 degrees C but to different extents, depending on the temperature and loading conditions. For nanoindentation, we observe that phase transformation is dominant below 100 degrees C but that deformation by twinning along {111} planes dominates at 150 degrees C and 200 degrees C. This work, therefore, provides clear insight into the temperature dependent deformation mechanisms in dc-Si at the nano

  • 78. Klimashin, F. F.
    et al.
    Riedl, H.
    Primetzhofer, Daniel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Tillämpad kärnfysik.
    Paulitsch, J.
    Mayrhofer, P. H.
    Composition driven phase evolution and mechanical properties of Mo-Cr-N hard coatings2015Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 118, nr 2, artikel-id 025305Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Although many research activities concentrate on transition metal nitrides, due to their excellent properties, only little is known about Mo-N based materials. We investigate in detail the influence of Cr on the structural evolution and mechanical properties of Mo-N coatings prepared at different nitrogen partial pressures. The chemical composition as well as the structural development of coatings prepared with N-2-to-total pressure ratios (p(N2)/p(T)) of 0.32 and 0.44 can best be described by the quasi-binary Mo2N-CrN tie line. Mo2N and CrN are face centered cubic (fcc), only that for Mo2N half of the N-sublattice is vacant. Consequently, with increasing Cr content, also the N-sublattice becomes less vacant and the chemical composition of fcc single-phase ternaries can be described as Mo1-xCrxN0.5(1+x). These coatings exhibit an excellent agreement between experimentally and ab initio obtained lattice parameters of fcc Mo1-xCrxN0.5(1+x). When increasing the N-2-to-total pressure ratio to pN(2)/p(T) = 0.69, the N-sublattice is already fully occupied for Cr-additions of x >= 0.4, as suggested by elastic recoil detection analysis and lattice parameter variations. The latter follows the ab initio obtained lattice parameters along the quasi-binary MoN-CrN tie line for x >= 0.5. The single-phase fcc coating with Cr/(Mo+Cr) of x similar to 0.2, prepared with pN(2)/p(T) = 0.32, exhibits the highest hardness of similar to 34 GPa among all coatings studied. (C) 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.

  • 79.
    Knut, Ronny
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Lindblad, Rebecka
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Grachev, Sergey
    Faou, Jean-Yvon
    Gorgoi, Mihaela
    Rensmo, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Søndergård, Elin
    Karis, Olof
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Reactive ZnO/Ti/ZnO interfaces studied by hard x-ray photoelectron spectroscopy2014Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 115, nr 4, s. 043714-043714-7Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The chemistry and intermixing at buried interfaces in sputter deposited ZnO/Ti/ZnO thin layers were studied by hard x-ray photoelectron spectroscopy. The long mean free path of the photoelectrons allowed for detailed studies of the oxidation state, band bending effects, and intrinsic doping of the buried interfaces. Oxidation of the Ti layer was observed when ZnO was deposited on top. When Ti is deposited onto ZnO, Zn Auger peaks acquire a metallic character indicating a strong reduction of ZnO at the interface. Annealing of the stack at 200 °C results in further reduction of ZnO and oxidation of Ti. Above 300 °C, oxygen transport from the bulk of the ZnO layer takes place, leading to re-oxidation of ZnO at the interface and further oxidation of Ti layer. Heating above 500 °C leads to an intermixing of the layers and the formation of a ZnxTiOy compound.

  • 80.
    Konôpková, Zuzana
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet.
    Peter, Lazor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet.
    Faramarz, Tutti
    Thermal pressure and displacements in the laser heated diamond anvil cellIngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550Artikel i tidskrift (Övrigt vetenskapligt)
  • 81.
    Kosyak, Volodymyr
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Postnikov, A. V.
    Univ Lorraine, ICPM, Inst Jean Barriol, LCP A2MC, 1 Bd Arago, F-57078 Metz, France..
    Scragg, Jonathan J.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Scarpulla, M. A.
    Univ Utah, Mat Sci & Engn, Salt Lake City, UT 84112 USA.;Univ Utah, Elect & Comp Engn, Salt Lake City, UT 84112 USA..
    Platzer Björkman, Charlotte
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Calculation of point defect concentration in Cu2ZnSnS4: Insights into the high-temperature equilibrium and quenching2017Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 122, nr 3, artikel-id 035707Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Herein, we study the native point defect equilibrium in Cu2ZnSnS4 (CZTS) by applying a statistical thermodynamic model. The stable chemical- potential space (SCPS) of CZTS at an elevated temperature was estimated directly, on the basis of deviations from stoichiometry calculated for the different combinations of chemical potential of the components. We show that the SCPS is narrow due to high concentration of (V-Cu(-) Zn-Cu(+)) complex which is dominant over other complexes and isolated defects. The CZTS was found to have p-type conductivity for both stoichiometric and Cu-poor/Zn-rich composition. It is established that the reason for this is that the majority of donor-like Zn-Cu(+) antisites are involved in the formation of (V-Cu(-) Zn-Cu(+)) complex making Cu-Zn dominant and providing p- type conductivity even for Cu-poor/Zn-rich composition. However, our calculation reveals that the hole concentration is almost insensitive to the variation of the chemical composition within the composition region of the single-phase CZTS due to nearly constant concentration of dominant charged defects. The calculations for the full equilibrium and quenching indicate that hole concentration is strongly dependent on the annealing temperature and decreases substantially after the drastic cooling. This means that the precise control of annealing temperature and post-annealing cooling rate are critical for tuning the electrical properties of CZTS.

  • 82. Kotmool, Komsilp
    et al.
    Bovornratanaraks, Thiti
    Chakraborty, Sudip
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    The effect of morphology and confinement on the high-pressure phase transition in ZnO nanostructure2015Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 117, nr 11, artikel-id 114309Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The transition pressure (Pt) of the B4-to-B1 phase transformation of zinc oxide nanoparticle (n-ZnO) structures was investigated in terms of their size and morphology. Nanorods, nanopencils, nanopyramids, nanowires, and nanotubes of the B4 phase in various sizes were directly built up by accounting for the atomic basis of the core and surface regions. The previously proposed transformation path was performed for constructing shapes and sizes compatible with B1 phases. Using systematic density functional theory, the surfaces were cleaved from the optimized crystal structures at different pressures in both the B4 and B1 phases. A method for calculating the surface energy at different pressures is proposed using an asymmetric slab model. Using the proposed model, the transition pressure of n-ZnO structures was found to significantly depend on their morphology and size, which is in good agreement with the available experimental reports.  

  • 83.
    Kovacs, A
    et al.
    Center for Electron Nanoscopy, Technical University of Denmark, Kongens Lyngby, Danmark.
    Sadowski, J
    MAX-Lab, Lund University, och Institute of Physics, Polish Adacemy of Sciences, Warszawa, Polen.
    Kasama, T
    Center for Electron Nanoscopy, Technical University of Denmark, Kongens Lyngby, Danmark.
    Domagala, J
    Institute of Physics, Polish Adacemy of Sciences, Warszawa, Polen.
    Mathieu, Roland
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Dietl, T
    Institute of Physics, Polish Adacemy of Sciences, Warszawa, Polen, and, Center for Electron Nanoscopy, Technical University of Denmark, Kongens Lyngby, Danmark.
    Dunin-Borkowski, R E
    Center for Electron Nanoscopy, Technical University of Denmark, Kongens Lyngby, Danmark.
    Voids and Mn-rich inclusions in a (Ga,Mn)As ferromagnetic semiconductor investigated by transmission electron microscopy2011Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 109, nr 8, s. 083546-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Voids adjacent to cubic (ZnS-type) and hexagonal (NiAs-type) Mn-rich nanocrystals are characterized using aberration-corrected transmission electron microscopy in an annealed Ga0.995Mn0.005As magnetic semiconductor specimen grown by molecular beam epitaxy. Nanobeam electron diffraction measurements suggest that the nanocrystals exhibit deviations in lattice parameter as compared to bulk MnAs. After annealing at 903 K, the magnetic transition temperature of the specimen is likely to be dominated by the presence of cubic ferromagnetic nanocrystals. In situ annealing inside the electron microscope is used to study the nucleation, coalescence, and grain growth of individual nanocrystals.

  • 84. Krysztopa, Adam
    et al.
    Igalson, Małgorzata
    Aida, Yasuhiro
    Larsen, Jes K
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Gütay, Levent
    Siebentritt, Susanne
    Defect levels in the epitaxial and polycrystalline CuGaSe2 by photocurrent and capacitance methods2011Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 110, nr 10, s. 103711-Artikel i tidskrift (Refereegranskat)
  • 85.
    Kubart, Tomas
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Aijaz, Asim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Evolution of sputtering target surface composition in reactive high power impulse magnetron sputtering2017Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 121, nr 17, artikel-id 171903Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The interaction between pulsed plasmas and surfaces undergoing chemical changes complicates physics of reactive High Power Impulse Magnetron Sputtering (HiPIMS). In this study, we determine the dynamics of formation and removal of a compound on a titanium surface from the evolution of discharge characteristics in an argon atmosphere with nitrogen and oxygen. We show that the time response of a reactive process is dominated by surface processes. The thickness of the compound layer is several nm and its removal by sputtering requires ion fluence in the order of 1016 cm−2, much larger than the ion fluence in a single HiPIMS pulse. Formation of the nitride or oxide layer is significantly slower in HiPIMS than in dc sputtering under identical conditions. Further, we explain very high discharge currents in HiPIMS by the formation of a truly stoichiometric compound during the discharge off-time. The compound has a very high secondary electron emission coefficient and leads to a large increase in the discharge current upon target poisoning.

  • 86. Kukli, Kaupo
    et al.
    Ritala, Mikko
    Sundqvist, Jonas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Aarik, Jaan
    Lu, Jun
    Sajavaara, Timo
    Leskelä, Markku
    Hårsta, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Properties of hafnium oxide films grown by atomic layer deposition from hafnium tetraiodide and oxygen2002Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 92, nr 10, s. 5698-5703Artikel i tidskrift (Refereegranskat)
  • 87. Kuz'min, M. D.
    et al.
    Skokov, K. P.
    Radulov, I.
    Schwoebel, C. A.
    Foro, S.
    Donner, W.
    Werwinski, M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    Rusz, Jan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Delczeg-Czirjak, Erna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Gutfleisch, O.
    Magnetic anisotropy of La2Co72015Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 118, nr 5, artikel-id 053905Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A magnetization study of a La2Co7 single crystal has obtained the following anisotropy constants: K-1 = 1.4 MJ/m(3) and K-2 = 0.02 MJ/m(3) (at room temperature). The corresponding anisotropy field is 6.7 T; an earlier report of a much higher value (17 T) has not been confirmed. A significant (10%) magnetization anisotropy has been observed. Density-functional calculations are in qualitative agreement with the new data. (C) 2015 AIP Publishing LLC.

  • 88.
    Kádas, Krisztina
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Eriksson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Skorodumova, Natalia V.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Highly anisotropic sliding at TiN/Fe interfaces: A first principles study2010Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 108, nr 11, s. 113511-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    By means of first principles density functional theory, we investigate the properties of the TiN(001)/fcc Fe(111) and TiN(001)/bcc Fe(110) interfaces. We demonstrate that along certain directions Fe slides with negligible energy barriers against TiN at both interfaces, whereas sliding along other directions is involved with significant energy barriers. The interface between bcc Fe and TiN has a low energy barrier for sliding along the [110] direction of the TiN lattice, as does sliding along the [010] direction at TiN(001)/fcc Fe(111). For fcc Fe on TiN, a large energy barrier is found for sliding along the [100] direction of the TiN lattice. We show that this phenomenon and the stability of these interfaces are determined by the interplay between N–Fe bonding and Ti–Fe antibonding interactions.

  • 89.
    Landström, Lars
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi.
    Márton, Zs.
    Arnold, N.
    Högberg, Hans
    Boman, Mats
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi.
    Heszler, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    In-situ monitoring and characterization of Nanoparticles During W Ablation in N2 Atmosphere2003Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 94, nr 3, s. 2011-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    ABSTRACT Nanoparticles were generated by pulsed laser ablation of tungsten in a N[sub 2] ambient at atmospheric pressure. Size distributions and concentrations were monitored in situ versus laser fluence, repetition rate, and ablated spot size, by a differential mobility analyzer and a particle counter. The multishot ablation threshold was determined to be ∼6 J/cm² for the laser used (ArF excimer, δ = 193 nm). Mostly small, nonlognormally, distributed particles (<20 nm in diameter) were generated below the ablation threshold (Φ[sub th]), and the relative concentration of larger particulates (>20 nm in diameter) increased above Φ[sub th]. Modeling of the temperature and ablated depth dependence on fluence showed that the formation of clusters below Φ[sub th] could not be assigned to a thermal process, but are connected to particle condensation from a photochemically desorbed thin layer. X-ray diffraction and x-ray photoelectron spectroscopy analysis performed on polydisperse nanoparticles revealed an amorphous phase of the particles, and the elemental composition was found to be WN[sub 0.3].

  • 90.
    Larsen, Jes K
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Li, Shuyi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Scragg, Jonathan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Ren, Yi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Hägglund, Carl
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Heinemann, Marc
    Kretzschmar, Steffen
    Unold, Thomas
    Platzer-Björkman, Charlotte
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Interference effects in photoluminescence spectra of Cu2ZnSnS4 and Cu(In,Ga)Se2 thin films2015Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 118, nr 3, artikel-id 035307Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Photoluminescence (PL) is commonly used for investigations of Cu2ZnSnS(e)4 [CZTS(e)] and Cu(In,Ga)Se2 (CIGS) thin film solar cells. The influence of interference effects on these measurements is, however, largely overlooked in the community. Here, it is demonstrated that PL spectra of typical CZTS absorbers on Mo/glass substrates can be heavily distorted by interference effects. One reason for the pronounced interference in CZTS is the low reabsorption of the PL emission that typically occurs below the band gap. A similar situation occurs in band gap graded CIGS where the PL emission originates predominantly from the band gap minimum located at the notch region. Based on an optical model for interference effects of PL emitted from a thin film, several approaches to reduce the fringing are identified and tested experimentally. These approaches include the use of measured reflectance data, a calculated interference function, use of high angles of incidence during PL measurements as well as the measurement of polarized light near the Brewster angle.

  • 91.
    Lawniczak-Jablonska, Krystyna
    et al.
    Polish Academy of Sciences, Warsaw.
    Wolska, Anna
    Polish Academy of Sciences, Warsaw.
    Bak-Misiuk, Jadwiga
    Polish Academy of Sciences, Warsaw.
    Dynowska, Elzbieta
    Polish Academy of Sciences, Warsaw.
    Romanowski, Przemyslaw
    Polish Academy of Sciences, Warsaw.
    Domagala, Jaroslaw Z.
    Polish Academy of Sciences, Warsaw.
    Minikayev, Roman
    Polish Academy of Sciences, Warsaw.
    Wasik, Dariusz
    University of Warsaw.
    Klepka, Marcin T.
    Polish Academy of Sciences, Warsaw.
    Sadowski, Janusz
    Polish Academy of Sciences, Warsaw.
    Barcz, Adam
    Polish Academy of Sciences, Warsaw.
    Dluzewski, Piotr
    Polish Academy of Sciences, Warsaw.
    Kret, Sławomir
    Polish Academy of Sciences, Warsaw.
    Twardowski, Andrzej
    University of Warsaw.
    Kamińska, Maria
    University of Warsaw.
    Persson, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Yt- och gränsskiktsvetenskap.
    Arvanitis, Dimitri
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Yt- och gränsskiktsvetenskap. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Holub-Krappe, Elisabeth
    Helmholtz Centre Berlin for Materials and Energy.
    Kwiatkowski, Adam
    University of Warsaw.
    Structural and magnetic properties of the molecular beam epitaxy grown MnSb layers on GaAs substrates2009Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 106, nr 8, s. 083524-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The structural and magnetic properties of MnSb layers grown on two   differently oriented GaAs substrates are reported. The MnSb compounds   grow nonhomogenously both on GaAs (111) B and on GaAs (100) substrates.   In x-ray diffraction studies the formation of two epitaxial domains is   observed depending on the crystallographic orientation of the   substrate. The observed diffusion of Ga atoms from the substrate to the   layers results in the formation of an additional Mn-rich cubic phase of   GaMnSb. In the case of the (100) oriented substrate, the diffusion of   Mn into the substrate was additionally found. Traces of other phases   were also noticed. The complex morphology of the layers is found to   influence their magnetic properties. Magnetic force microscopy images   revealed an inhomogenous distribution of the magnetic force gradient on   the surface and the formation of magnetic domains in the samples. X-ray   absorption studies of the chemical bonding and local atomic structure   around Mn atoms confirmed high structural and chemical disorder in the   samples. The chemical bonding of the dominating fraction of Mn atoms is   found, however, similar to that in the reference MnSb powder. The x-ray   magnetic circular dichroism measurements reveal an enhanced orbital   moment and a reduced spin moment, which is most likely caused by the   presence of different phases and a Mn-rich surface in the investigated   samples.

  • 92. Legut, D.
    et al.
    Tesch, M. F.
    Mertins, H. -Ch.
    Gilbert, M. C.
    Jansing, C.
    Buergler, D. E.
    Schneider, C. M.
    Gaupp, A.
    Hamrle, J.
    Oppeneer, Peter. M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Influence of the crystal structure of thin Co films on X-ray magnetic linear dichroism-Comparison of ab initio theory and reflectometry experiments2014Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 115, nr 17, s. 17E132-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report an investigation of the influence of the crystal structure of Co thin films on the X-ray magnetic linear dichroism (XMLD) spectrum. We compare XMLD spectra measured in reflection at the 3p-edges for two distinct orientations of the magnetization in the crystalline Co film with ab initio calculated spectra. The latter was computed for the face-centered cubic as well as the hexagonal-close packed crystal structures of Co. We find that the XMLD signal is strongly dependent on the magnetization direction with respect to the crystal axes as well as strongly influenced by the crystal structure. (C) 2014 AIP Publishing LLC.

  • 93.
    Lewin, Erik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Wilhelmsson, Ola
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Jansson, Ulf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Nanocomposite nc-TiC/a-C thin films for electrical contact applications2006Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 100, nr 5, s. 054303-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thin film nanocomposites of nanocrystalline TiC embedded in a matrix of amorphous carbon have been prepared by nonreactive unbalanced dc-magnetron sputtering. These samples have been tested as coating materials for electrical contacts and show great potential as an alternative to traditional metallic coatings for contacts subjected to wear and friction. Through variation of composition and deposition temperature different microstructures have been attained. The coatings have been characterized using x-ray diffraction, x-ray photoelectron spectroscopy, and Raman spectroscopy. The performance of the coatings has been coupled to the microstructure whereby tuning and optimization possibilities have been identified.

  • 94.
    Li, Guijiang
    et al.
    KTH Royal Inst Technol, Dept Mat Sci & Engn, Appl Mat Phys, SE-10044 Stockholm, Sweden..
    Eriksson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Johansson, Börje
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. KTH Royal Inst Technol, Dept Mat Sci & Engn, Appl Mat Phys, SE-10044 Stockholm, Sweden..
    Vitos, Levente
    KTH Royal Inst Technol, Dept Mat Sci & Engn, Appl Mat Phys, SE-10044 Stockholm, Sweden.;Wigner Res Ctr Phys, Res Inst Solid State Phys & Opt, POB 49, H-1525 Budapest, Hungary..
    Thermodynamic-state and kinetic-process dependent dual ferromagnetic states in high-Si content FeMn(PSi) alloys2015Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 118, nr 21, artikel-id 213903Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have found that thermodynamic state and kinetic process co-determine the dual ferromagnetic (FM) orders in high-Si content FeMnP1-xSix (0.25 < x < 0.5). Alloys undergoing high temperature annealing and quenching process prefer a high magnetic moment FM state in a chemically partial disordered structure with low c/a ratio. This mechanism is suggested to be responsible for the often discussed virgin effect as well. A chemically ordered structure obtained by a slow cooling process from a relatively low annealing temperature and the increase in Si content stabilize a metastable lattice with high c/a ratio and FM order with low magnetic moment. The non-simultaneity of the magnetic and structural transitions can be responsible for the occurrence of FM state in the high c/a range. Thus, a c/a ratio that changes from high to low is physically plausible to stabilize the metastable FM order at low temperature. Our theoretical observations indicate that suitable thermodynamic state and kinetic diffusion process is crucial for optimizing magnetocaloric properties and exploring feasible magnetocaloric materials.

  • 95.
    Li, Hu
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap. Shandong Univ, Sch Mech Engn, Minist Educ, Key Lab High Efficiency & Clean Mech Manufacture, Jinan 250061, Shandong, Peoples R China;Univ Manchester, Sch Elect & Elect Engn, Manchester M13 9PL, Lancs, England.
    Liu, Jiangwei
    Shandong Univ, Sch Mech Engn, Minist Educ, Key Lab High Efficiency & Clean Mech Manufacture, Jinan 250061, Shandong, Peoples R China.
    Papadakis, Raffaello
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Direct measurement of the surface energy of single-walled carbon nanotubes through atomic force microscopy2019Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 126, nr 6, artikel-id 065105Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Surface energy in nanomaterials is an essential parameter demonstrating a key role in their surface interactions and their functionalization aptitude. In this work, a new and facile methodology based on atomic force microscopy for the measurement of the surface energy of single-walled carbon nanotubes (SWCNTs) is reported. The proposed approach starts with the calibration based on a well-studied material, graphite, and the precision of the technique is confirmed by the measurement of the surface energy of multiwalled carbon nanotubes. Our measurements show that SWCNTs display a surface energy of 52.8mJ/m(2), which is in very good agreement with theoretical predictions of the measured property. Our experimental approach is essentially applicable to other nano-objects in contrast to conventional wet angle methods which are currently employed mainly in bulk materials.

  • 96.
    Li, Jiantong
    et al.
    School of Information and Communication, KTH, Kista.
    Unander, Tomas
    Dept of Information Technology and Media, Mid Sweden University, Sundsvall.
    Cabezas, Ana Lopez
    School of Information and Communication, KTH, Kista, and , iPack Vinn Excellent center, KTH, Kista.
    Shao, Botao
    School of Information and Communication, KTH, Kista, and , iPack Vinn Excellent center, KTH, Kista.
    Liu, Zhiying
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Feng, Yi
    School of Information and Communication, KTH, Kista, and , iPack Vinn Excellent center, KTH, Kista.
    Forsberg, Esteban Bernales
    School of Information and Communication, KTH, Kista.
    Zhang, Zhi-Bin
    School of Information and Communication, KTH, Kista, and , iPack Vinn Excellent center, KTH, Kista.
    Jogi, Indrek
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Gao, Xindong
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Boman, Mats
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Zheng, Li-Rong
    School of Information and Communication, KTH, Kista, and , iPack Vinn Excellent center, KTH, Kista.
    Östling, Mikael
    School of Information and Communication, KTH, Kista.
    Nilsson, Hans-Erik
    Dept of Information Technology and Media, Mid Sweden University, Sundsvall.
    Zhang, Shi-Li
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Ink-jet printed thin-film transistors with carbon nanotube channels shaped in long strips2011Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 109, nr 8, s. 084915-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present work reports on the development of a class of sophisticated thin-film transistors (TFTs) based on ink-jet printing of pristine single-walled carbon nanotubes (SWCNTs) for the channel formation. The transistors are manufactured on oxidized silicon wafers and flexible plastic substrates at ambient conditions. For this purpose, ink-jet printing techniques are developed with the aim of high-throughput production of SWCNT thin-film channels shaped in long strips. Stable SWCNT inks with proper fluidic characteristics are formulated by polymer addition. The present work unveils, through Monte Carlo simulations and in light of heterogeneous percolation, the underlying physics of the superiority of long-strip channels for SWCNT TFTs. It further predicts the compatibility of such a channel structure with ink-jet printing, taking into account the minimum dimensions achievable by commercially available printers. The printed devices exhibit improved electrical performance and scalability as compared to previously reported ink-jet printed SWCNT TFTs. The present work demonstrates that ink-jet printed SWCNT TFTs of long-strip channels are promising building blocks for flexible electronics.

  • 97.
    Li, Shuyi
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Namura, Kyoko
    Kyoto University - Katsura.
    Suzuki, Motofumi
    Kyoto University - Katsura.
    Niklasson, Gunnar A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Thermochromic VO2 nanorods made by sputter deposition: Growth conditions and optical modeling2013Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 114, nr 3, s. 033516-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Reactive dc magnetron sputtering onto glass-based substrates yielded deposits of thermochromic VO2 with well-developed nanorods and nanowires. Their formation was promoted by high substrate temperature (above similar to 500 degrees C), sufficient film thickness, proper inlet of the reactive gas, dispersed gold "seeds," and pronounced substrate roughness. Rutherford back scattering ascertained mass thicknesses, scanning electron microscopy depicted the nanostructures, and glancing incidence X-ray diffraction proved that single-phase VO2 was normally formed. Spectrophotometric measurements of total and diffuse transmittance and reflectance on VO2 thin films, at room temperature and similar to 100 degrees C, allowed us to determine complex dielectric functions below and above the "critical" temperature for thermochromic switching (similar to 68 degrees C). These data were then used in computations based on the Bruggeman effective medium theory applied to randomly oriented prolate spheroidal structural units to derive the optical properties of the deposits. Experimental and computed data on spectral absorptance were found to be in good qualitative agreement.

  • 98.
    Li, Shuyi
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Niklasson, Gunnar A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Nanothermochromics: Calculations for VO2 nanoparticles in dielectric hosts show much improved luminous transmittance and solar energy transmittance modulation2010Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 108, nr 6, s. 063525-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    VO2-based films are thermochromic and show infrared reflectance above a "critical" temperature in the vicinity of room temperature. Implementations on energy efficient windows have been discussed for decades but have been severely curtailed since the luminous absorptance is undesirably large and the solar energy transmittance modulation is too small. Here we show by calculations based on effective medium theory that dilute composites with VO2 nanoparticles embedded in hosts with properties mimicking glass or polymer can yield significantly decreased luminous absorption jointly with much enhanced transmittance modulation of solar energy. These results demonstrate that VO2-based nanothermochromics opens new avenues toward energy efficient fenestration.

  • 99.
    Li, Shuyi
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Niklasson, Gunnar A
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Nanothermochromics with VO2-based core-shell structures: Calculated luminous and solar optical properties2011Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 109, nr 11, s. 113515-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Composites including VO2-based thermochromic nanoparticles are able to combine high luminous transmittance T-lum with a significant modulation of the solar energy transmittance Delta T-sol at a "critical" temperature in the vicinity of room temperature. Thus nanothermochromics is of much interest for energy efficient fenestration and offers advantages over thermochromic VO2-based thin films. This paper presents calculations based on effective medium theory applied to dilute suspensions of core-shell nanoparticles and demonstrates that, in particular, moderately thin-walled hollow spherical VO2 nanoshells can give significantly higher values of Delta T-sol than solid nanoparticles at the expense of a somewhat lowered T-lum. This paper is a sequel to a recent publication [S.-Y. Li, G. A. Niklasson, and C. G. Granqvist, J. Appl. Phys. 108, 063525 (2010)].

  • 100.
    Li, Shu-Yi
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Niklasson, Gunnar A
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Thermochromic undoped and Mg-doped VO2 thin films and nanoparticles: Optical properties and performance limits for energy efficient windows2014Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 115, nr 5, s. 053513/1-/10Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Undoped and Mg-doped thermochromic VO2 films with atom ratios z equivalent to Mg/(Mg + V) of 0 <= z < 0.21 were deposited by reactive DC magnetron sputtering onto heated glass and carbon substrates. Elemental compositions were found by Rutherford backscattering spectrometry. Optical constants were determined from transmittance and reflectance measurements and were used for modeling the optical properties of thin films and dilute nanoparticle composite layers below and above the critical temperature for thermochromic switching between a low-temperature infrared transparent state and a high-temperature infrared reflecting or absorbing state. Mg-doped films showed superior luminous transmittance T-lum and solar transmittance modulation Delta T-sol compared to undoped VO2 films, and both of these parameters could be further enhanced by anti-reflection. VO2-containing nanocomposites had much larger values of T-lum and Delta T-sol than VO2-based films. Mg-doping was found to erode the properties of the nanocomposites. Approximate performance limits are given on T-lum and Delta T-sol for thermochromic VO2 films, with and without Mg doping and antireflection coating, and also for VO2-containing dilute nanocomposites.

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