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  • 201.
    Larsson, Karin
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Björkman, H
    Technology, Department of Materials Science. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Hjort, K
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Role of water and oxygen in wet- and dry-oxidation of diamond2001In: J. Appl. Phys., Vol. 90, p. 1026-1034Article in journal (Refereed)
  • 202.
    Larsson, Karin
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Carlsson, Jan-Otto
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Incorporation of C into growth steps of diamond (111)2001In: PHYSICA STATUS SOLIDI A-APPLIED RESEARCH, ISSN 0031-8965, Vol. 186, no 2, p. 319-330Article in journal (Refereed)
    Abstract [en]

    Different surface processes occuring during growth of diamond (111) have theoretically been investigated by using various quantum mechanical methods (including molecular dynamic simulations). A final incorporation of C-containing growth precursors into th

  • 203.
    Larsson, Karin
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Carlsson, Jan-Otto
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Partial electron transfer during vapor growth of diamond on a (111) surface1999In: JOURNAL OF PHYSICAL CHEMISTRY B, ISSN 1089-5647, Vol. 103, no 14, p. 2735-2739Article in journal (Other scientific)
    Abstract [en]

    During diamond growth, surface vacancies are formed and diamond grows by adding carbon-carrying species to these vacancies. In the present investigation, the correlation between adsorption energies and accompanying partial electron transfer in the newly f

  • 204.
    Larsson, Karin
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Carlsson, Jan-Otto
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Surface migration during diamond growth studied by molecular orbital calculations1999In: PHYSICAL REVIEW B-CONDENSED MATTER, Vol. 59, no 12, p. 8315-8322Article in journal (Refereed)
    Abstract [en]

    Migration of various important species (H, CH3, CH2, C2H, and C2H2) on a diamond (111) surface has been investigated theoretically, using a cluster approach and the second-order Møller-Plesset perturbation theory. The order of the energies (barriers) obtained for a single jump between two neighboring radical sites is CH2<H<C2H≈CH3 (52, 248, 350, and 353 kJ/mol, respectively). The C2H2 species is assumed to migrate by an alternating onefold and difold site adsorption to the surface. The corresponding barrier obtained for C2H2 is 186 kJ/mol, which is somewhere in between that of CH2 and H. The present type of surface migration of chemisorbed species will, with one exception, be energetically favorable in comparison to any desorption process. In the case of C2H2, a desorption process will be energetically favorable.

  • 205.
    Larsson, Karin
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Carlsson, Jan-Otto
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Surface processes in cubic boron nitride growth: A theoretical study1999In: JOURNAL OF PHYSICAL CHEMISTRY B, ISSN 1089-5647, Vol. 103, no 31, p. 6533-6538Article in journal (Other scientific)
    Abstract [en]

    Various surface processes for the system B/N/H/F occurring during CVD growth of c-BN (111) have been investigated theoretically, using quantum mechanical methods. Both F and H species were found to be efficient as surface stabilizing agents. Mainly the H-

  • 206.
    Larsson, Karin
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Ristein, Juergen
    Diamond Surface Conductivity under Atmospheric Conditions: Theoretical Approach2005In: J. Phys. Chem. B, Vol. 109, no 20, p. 10304-10311Article in journal (Refereed)
    Abstract [en]

    The electron transfer from an H-terminated diamond (100)-2 × 1 surface to a neutral or acidic water adlayer has been theoretically investigated, using quantum mechanical DFT calculations under periodic boundary conditions. A surface conductivity of p-type was found to be induced by the acidic environment. An electron transfer of 1.8 electrons per surface unit cell was observed to take place from the upper part of the diamond valence band to the lowest unoccupied molecular level of the aqueous adlayer that contains one H3O+ ion. The result is a hole delocalized over the whole diamond model slab. Also, a pronounced weakening of the H3O+ bonds by the interaction with the diamond surface is observed.

  • 207.
    Larsson, Karin
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Technology, Department of Engineering Sciences, Electronics.
    Westlinder, Jörgen
    Department of Materials Science. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Blom, Hans-Olof
    Department of Materials Science. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Olsson, Jörgen
    Department of Materials Science. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Substitutional Effects of the Dielectric Constant in Ta2O52001In: Presented at AVS, Oct, 2001Conference paper (Refereed)
  • 208.
    Larsson, Mina
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. strukturkemi.
    Lindgren, Jan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. strukturkemi.
    Ljunglöf, A
    Knuuttila, K-G
    Confocal Raman and fluorescence spectroscopy applied to polymeric chromatographic adsorbent particles2002In: Journal of Chromatography A, Vol. 954, p. 151-158Article in journal (Refereed)
  • 209.
    Lashgari, Koroush
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Westin, Gunnar
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Preparation of PZT Film on Conducting Ceramic Electrodes using Ti- and Zr-Alkoxides and Pb(NO3)2(EO3)1.52002In: 10th Internaitonal Ceramics Congress 2002 Proceedings, 2002, p. 517-Conference paper (Refereed)
  • 210. Lauridsen, J.
    et al.
    Eklund, P.
    Jensen, J.
    Ljungcrantz, H.
    Öberg, A.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Flink, A.
    Högberg, H.
    Hultman, L.
    Microstructure evolution of Ti-Si-C-Ag nanocomposite coatings deposited by DC magnetron sputtering2010In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 58, no 20, p. 6592-6599Article in journal (Refereed)
    Abstract [en]

    Nanocomposite coatings consisting of Ag and TiCx (x < 1) crystallites in a matrix of amorphous SiC were deposited by high-rate magnetron sputtering from Ti-Si-C-Ag compound targets. Different target compositions were used to achieve coatings with a Si content of similar to 13 at.%, while varying the C/Ti ratio and Ag content. Electron microscopy, helium ion microscopy, X-ray photoelectron spectroscopy and X-ray diffraction were employed to trace Ag segregation during deposition and possible decomposition of amorphous SiC. Eutectic interaction between Ag and Si is observed, and the Ag forms threading grains which coarsen with increased coating thickness. The coatings can be tailored for conductivity horizontally or vertically by controlling the shape and distribution of the Ag precipitates. Coatings were fabricated with hardness in the range 10-18 GPa and resistivity in the range 77-142 mu Omega cm.

  • 211. Lauridsen, J.
    et al.
    Eklund, P.
    Joelsson, T.
    Ljungcrantz, H.
    Öberg, Å.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Beckers, M.
    Högberg, H.
    Hultman, L.
    High-rate deposition of amorphous and nanocomposite Ti-Si-C multifunctional coatings2010In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 205, no 2, p. 299-305Article in journal (Refereed)
    Abstract [en]

    Amorphous (a) and nanocomposite Ti-Si-C coatings were deposited at rates up to 16 mu m/h by direct current magnetron sputtering from a Ti3SiC2 compound target, using an industrial pilot-plant system, onto high-speed steel. Si, and SiO2 substrates as well as NI-plated Cu cylinders, kept at a temperature of 200 or 270 degrees C. Electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction analyses showed that TiC/a-C/a-SiC nanocomposites were formed consisting of textured TIC nanocrystallites (nc) embedded in a matrix of a-C and a-SiC. Elastic recoil detection analysis showed that coatings deposited at a target-to-substrate distance of 2 cm and an Ar pressure of 10 mTorr have a composition close to that of the Ti3SiC2 compound target, as explained by ballistic transport of the species Increased target-to-substrate distance from 2 cm to 8 cm resulted in a higher carbon-to-titanium ratio in the coatings than for the Ti3SiC2 compound target, due to different gas-phase scattering properties between the sputtered species The coating microstructure could be modified from nanocrystalline to predominantly amorphous by changing the pressure and target-to-substrate conditions to 4 mTorr and 2 cm, respectively. A decreased pressure from 10 mTorr to 4 or 2 mTorr at a target-to-substrate distance of 2 cm decreased the deposition rate up to a factor of similar to 7 as explained by resputtering and an increase in the plasma sheath thickness. The coatings exhibited electrical resistivity in the range 160-800 mu Omega cm, contact resistance down to 08 m Omega at a contact force of 40 N, and nanoindentation hardness in the range of 6-38 GPa.

  • 212. Lee, SK
    et al.
    Danielsson, E
    Zetterling, CM
    Östling, M
    Palmqvist, Jens-Petter
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Högberg, H
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Jansson, Ulf
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    The formation and characterization of epitaxial titanium carbide contacts to 4H-SiC2000In: Materials Research Society Proceeings, 2000, p. T6.9-Conference paper (Other scientific)
  • 213.
    Lee, SK
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry.
    Zetterling, CM
    Danielsson, E
    Ostling, M
    Palmquist, Jens-Petter
    Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Högberg, Hans
    Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Jansson, Ulf
    Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Electrical characterization of TiC ohmic contacts to aluminum ion implanted 4H-silicon carbide2000In: APPLIED PHYSICS LETTERS, ISSN 0003-6951, Vol. 77, no 10, p. 1478-1480Article in journal (Refereed)
    Abstract [en]

    We report on the investigation of epitaxial TiC ohmic contacts to Al ion implanted 4H-SiC. TiC ohmic contacts were formed by coevaporation of Ti and C-60 at low temperature (< 500 degrees C). A sacrificial silicon nitride (Si3N4) layer was deposited on th

  • 214.
    Lee, SK
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry.
    Zetterling, CM
    Ostling, M
    Palmquist, Jens-Petter
    Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Högberg, H
    Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Jansson, Ulf
    Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Low resistivity ohmic titanium carbide contacts to n- and p-type 4H-silicon carbide2000In: SOLID-STATE ELECTRONICS, ISSN 0038-1101, Vol. 44, no 7, p. 1179-1186Article in journal (Refereed)
    Abstract [en]

    Low resistivity Ohmic contacts of epitaxial titanium carbide to highly doped n- (1.3 x 10(19) cm(-3)) and p- (>10(20) cm(-3)) type epilayer on 4H-SiC were investigated. The titanium carbide contacts were epitaxially grown using coevaporation with an e-bea

  • 215.
    Lee, S.K.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Östling, C.M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Zetterling, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Palmquist, Jens-Petter
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Jansson, Ulf
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Low resistivity ohmic contacts on 4H-silicon carbide for high power and high temperature device applications2002In: Microelectronic Engineering, Vol. 60, no 1-2, p. 261-268Article in journal (Refereed)
    Abstract [en]

    We investigated titanium based ohmic contacts using co-evaporated epitaxial titanium carbide (TiC) on highly doped n+- and p+-type epilayers as well as Al ion implanted layers for high power and high temperature device application. Epitaxially grown TiC ohmic contacts on epilayers as well as Al implanted layers of 4H-SiC were formed by UHV co-evaporation with Ti and C60 at low substrate temperature. The specific contact resistance (ρC) was as low as 5×10−6, 2×10−5, and 2×10−5 Ωcm2 for TiC contacts on n+, on p+ epilayer, and on Al implanted layer, respectively, using a linear TLM measurement. In addition to TiC, we also investigated TiW (weight ratio 30:70) ohmic contacts to p- and n-type 4H-SiC for the purpose of long-term reliability tests at high temperature. The average ρC of sputtered TiW contacts was 4×10−5 for p+ and n+ epilayer. We also found that an evaporated top layer (Au or Pt) helps to protect from degradation of the contacts under long-term reliability tests with temperatures of up to 600°C in a vacuum chamber.

  • 216.
    Leifer, Klaus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Experimental Physics.
    Jafri, Hassan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Experimental Physics.
    Blom, Tobias
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Widenqvist, E
    Carva, Karel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Sanyal, Biplab
    Eriksson, Olle
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Quinlan, R
    Holloway, B
    Luna Innovations Incorporated, NanoWorks Division,521 Bridge Street, Danville, 24541, Virginia, USA.
    Surpi, A
    Control of Conductivity in Graphene by Formation of Defects2008Conference paper (Refereed)
  • 217.
    Leopold, Sofia
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Arrayet, J.C
    Bruneel, J.L
    Herranen, Merja
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Carlsson, Jan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Argoul, F
    Servant, L
    In Situ CRM Study of the Self-Oscillating Du-(II)-Lactate and Cu-(II)-Tartrate Systems2003In: J. Electrochem. Soc., Vol. 150, no 7, p. C472-C477Article in journal (Refereed)
  • 218.
    Leopold, Sofia
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Herranen, Merja
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Carlsson, Jan-Otto
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Nyholm, Leif
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    In situ pH measurement of the self-oscillating Cu(II)-lactate system using an electropolymerised polyaniline film as a micro pH sensor2003In: Journal of Electroanalytical Chemistry, Vol. 547, p. 45-52Article in journal (Refereed)
  • 219.
    Leopold, Sofia
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Schuchert, I.U.
    Lu, J.
    Toimil Molares, M.E.
    Herranen, Merja
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Carlsson, Jan-Otto
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Electrochemical deposition of cylindrical Cu/Cu2O microstructures2002In: Electrochimica Acta, Vol. 47, p. 4393-4397Article in journal (Refereed)
  • 220.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Design of carbide-based nanocomposite coatings2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis research on synthesis, microstructure and properties of carbide-based coatings is reported. These coatings are electrically conducting, and can be tailored for high hardness, low friction and wear, along with load-adaptive behaviour. Tailoring these properties is achieved by controlling the relative phase content of the material. Coatings have been synthesised by dc magnetron sputtering, and their structures have been characterised, mainly by X-ray photoelectron spectroscopy and X-ray diffraction.

    It has been shown that nanocomposites comprising of a nanocrystalline transition metal carbide (nc-MeCx, Me = Ti, Nb or V) and an amorphous carbon (a-C) matrix can result in low contact resistance in electrical contacts. Such materials also exhibit low friction and high resistance to wear, making them especially suitable for application in sliding contacts. The lowest contact resistance is attained for small amounts of the amorphous carbon phase.

    It has been shown that specific bonding structures are present in the interface between nc-TiCx and the a-C phases in the nanocomposite.  It was found in particular that Ti3d and C2p states are involved, and that considerable charge transfer occurs across the interface, thereby influencing the structure of the carbide.

    Further design possibilities were demonstrated for TiCx-based nanocomposites by alloying them with weakly carbide-forming metals, i.e., Me = Ni, Cu or Pt.  Metastable supersaturated solid solution carbides, (T1-xMex)Cy, were identified to result from this alloying process. The destabilisation of the TiCx-phase leads to changes in the phase distribution in the deposited nanocomposites, thus providing further control over the amount of carbon phase formed. Additional design possibilities became available through the decomposition of the metastable (Ti1-xMex)Cy phase through an appropriate choice of annealing conditions, yielding either more carbon phase or a new metallic phase involving Me. This alloying concept was also studied theoretically for all 3d transition metals using DFT techniques.

    It has also been demonstrated that Ar-ion etching (commonly used in the analysis of carbide based nanocomposites) can seriously influence the result of the analysis, especially for materials containing metastable phases. This implies that more sophisticated methods, or considerable care are needed in making these analyses, and that many of the earlier published results could well be in error.

    List of papers
    1. Influence of sputter damage on the XPS analysis of metastable nanocomposite coatings
    Open this publication in new window or tab >>Influence of sputter damage on the XPS analysis of metastable nanocomposite coatings
    Show others...
    2009 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 204, no 4, p. 455-462Article in journal (Refereed) Published
    Abstract [en]

    X-ray photoelectron spectroscopy (XPS) is a standard method of determining chemical bonding in e.g. nanocomposites. We demonstrate that sputter-cleaning of the sample prior to analysis can substantially alter the attained information. We present an in-depth analysis of sputter damage on binary and ternary TiC-based coatings in the Ti–Ni–C system. XPS was performed after sputter etching with different ion energies (0.15–4 keV). Results are compared to data from the bulk of undamaged samples attained using high kinetic energy XPS. We observe substantial sputter damage, strongly dependent on sputter energies and coating stability. Metastable samples exhibit severe sputter damage after etching with 4 keV. Additional samples from other Ti–Me–C (Me = Al, Fe, Cu or Pt) systems were also examined, and notable sputter damage was observed. This suggests that accurate analysis of any metastable nanocomposite requires careful consideration of sputter damages.

    Place, publisher, year, edition, pages
    Elsevier B.V., 2009
    Keywords
    Sputtering, X-ray photoelectron spectroscopy (XPS), Nanocomposite, Metastable phases, Sputtering artifacts
    National Category
    Chemical Sciences
    Research subject
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-109019 (URN)10.1016/j.surfcoat.2009.08.006 (DOI)000271337500010 ()
    Note
    Department of Materials Chemistry, The Ångström Laboratory, Uppsala University, Box 538, SE-751 21 Uppsala, Sweden Department of Physics, The Ångström Laboratory, Uppsala University, Box 530, SE-751 21 Uppsala, Sweden Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2017-12-13
    2. On the origin of a third spectral component of C1s XPS-spectra for nc-TiC/a-C nanocomposite thin films
    Open this publication in new window or tab >>On the origin of a third spectral component of C1s XPS-spectra for nc-TiC/a-C nanocomposite thin films
    Show others...
    2008 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 202, no 15, p. 3563-3570Article in journal (Refereed) Published
    Abstract [en]

    X-ray photoelectron spectroscopy (XPS) spectra of sputter-etched nc-TiC/a-C nanocomposite thin films published in literature show an extra feature of unknown origin in the C1s region. This feature is situated between the contributions of carbide and the carbon matrix. We have used high kinetic energy XPS (HIKE-XPS) on magnetron-sputtered nc-TiC/a-C thin films to show that this feature represents a third chemical environment in the nanocomposites, besides the carbide and the amorphous carbon. Our results show that component is present in as-deposited samples, and that the intensity is strongly enhanced by Ar+-ion etching. This third chemical environment may be due to interface or disorder effects. The implications of these observations on the XPS analysis of nanocomposites are discussed in the light of overlap problems for ternary carbon based systems.

    Keywords
    X-ray photoelectron spectroscopy (XPS), Nanocomposite coatings, Sputtering, Transmission electron microscopy (TEM)
    National Category
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-16522 (URN)10.1016/j.surfcoat.2007.12.038 (DOI)000255492700016 ()
    Available from: 2008-05-28 Created: 2008-05-28 Last updated: 2017-12-08
    3. Electronic structure and chemical bonding of nanocrystalline-TiC/amorphous-C nanocomposites
    Open this publication in new window or tab >>Electronic structure and chemical bonding of nanocrystalline-TiC/amorphous-C nanocomposites
    2009 (English)In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 80, no 23, p. 235108-Article in journal (Refereed) Published
    Abstract [en]

    The electronic structure of nanocrystalline (nc-) TiC/amorphous C nanocomposites has been investigated bysoft x-ray absorption and emission spectroscopy. The measured spectra at the Ti 2p and C 1s thresholds of thenanocomposites are compared to those of Ti metal and amorphous C. The corresponding intensities of theelectronic states for the valence and conduction bands in the nanocomposites are shown to strongly depend onthe TiC carbide grain size. An increased charge transfer between the Ti 3d-eg states and the C 2p states hasbeen identified as the grain size decreases, causing an increased ionicity of the TiC nanocrystallites. It issuggested that the charge transfer occurs at the interface between the nanocrystalline-TiC and the amorphous-Cmatrix and represents an interface bonding which may be essential for the understanding of the properties ofnc-TiC/amorphous C and similar nanocomposites.

    Keywords
    Nanokomposit, RIXS, XES, XAS, TEY, TFY, XPS, XRD
    National Category
    Condensed Matter Physics Inorganic Chemistry
    Research subject
    Physics; Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-111387 (URN)10.1103/PhysRevB.80.235108 (DOI)000273228800029 ()
    Available from: 2009-12-14 Created: 2009-12-13 Last updated: 2019-06-19Bibliographically approved
    4. Nanocomposite nc-TiC/a-C thin films for electrical contact applications
    Open this publication in new window or tab >>Nanocomposite nc-TiC/a-C thin films for electrical contact applications
    2006 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 100, no 5, p. 054303-Article in journal (Refereed) Published
    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.

    Keywords
    nanocomposites, titanium compounds, carbon, thin films, wear, friction, sputter deposition, crystal microstructure, X-ray diffraction, X-ray photoelectron spectra, Raman spectra, electrical contacts, contact resistance
    National Category
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-82095 (URN)10.1063/1.2336302 (DOI)000240602500096 ()
    Available from: 2006-09-18 Created: 2006-09-18 Last updated: 2017-12-14Bibliographically approved
    5. Industrialisation Study of Nanocomposite nc-TiC/a-C Coatings for Electrical Contact Applications
    Open this publication in new window or tab >>Industrialisation Study of Nanocomposite nc-TiC/a-C Coatings for Electrical Contact Applications
    Show others...
    2009 (English)In: Plasma Processes and Polymers, ISSN 1612-8850, Vol. 6, no S1, p. S928-S934Article in journal (Refereed) Published
    Abstract [en]

    Nanocomposite nc-TiC/a-C coatings were prepared by non-reactive magnetron sputtering in industrial scale equipment, under varying deposition conditions in order to investigate upscaling and possible industrialisation. The coatings were found to have similar microstructure and performance compared to previous laboratory scale experiments. The samples were characterised with XRD, XPS and SEM as well with ball-on-disc, nanoindentation and electrical measurements. Coatings containing a small fraction of a-C matrix phase were found to have promising both electrical properties (rho < 400 mu Omega cm and contact resistances down to 0.34 m Omega at 40 N) and tribological properties (f < 0.3 for 10 000 laps).

    Place, publisher, year, edition, pages
    WILEY-VCH Verlag GmbH & Co, 2009
    Keywords
    conductivity, inorganic materials, nanocomposites, thin films, tribology
    National Category
    Chemical Sciences Inorganic Chemistry Engineering and Technology
    Research subject
    Inorganic Chemistry; Chemistry with specialization in Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-109022 (URN)10.1002/ppap.200932303 (DOI)000272302900178 ()
    Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2016-04-14
    6. Carbon Release by Selective Alloying of Transition Metal Carbides
    Open this publication in new window or tab >>Carbon Release by Selective Alloying of Transition Metal Carbides
    Show others...
    2011 (English)In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 23, no 35, p. 355401-+Article in journal (Refereed) Published
    Abstract [en]

    We have performed first principles density functional theory calculations on TiC alloyed on the Ti sublattice with 3d transition metals ranging from Sc to Zn. The theory is accompanied by experimental investigations, both as regards materials synthesis as well as characterization. Our results show that by dissolving a metal with a weak ability to form carbides, the stability of the alloy is lowered and a driving force for the release of carbon from the carbide is created. During thin film growth of a metal carbide this effect will favour the formation of a nanocomposite with carbide grains in a carbon matrix. The choice of alloying element as well as its concentration will affect the relative amount of carbon in the carbide and in the carbon matrix. This can be used to design the structures of nanocomposites and their physical and chemical properties. One example of applications is as low-friction coatings. Of the materials studied, we suggest the late 3d transition metals as the most promising elements for this phenomenon, at least when alloying with TiC.

    National Category
    Inorganic Chemistry
    Research subject
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-123136 (URN)10.1088/0953-8984/23/35/355401 (DOI)
    Available from: 2009-10-12 Created: 2009-10-12 Last updated: 2017-12-12Bibliographically approved
    7. Synthesis, structure and properties of Ni-alloyed TiCx-based thin films
    Open this publication in new window or tab >>Synthesis, structure and properties of Ni-alloyed TiCx-based thin films
    Show others...
    2010 (English)In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 20, no 28, p. 5950-5960Article in journal (Refereed) Published
    Abstract [en]

    By using non-reactive sputter deposition at low temperatures metastable solid solution phases in the Ti–Ni–C system were synthesized. Produced thin films were either single phase carbides or nanocomposite of nanocrystalline carbide and amorphous C. In the Ni-containing samples a supersaturated solid solution phase (Ti1−xNix)Cy was identified, and was present either as single phase or in a nanocomposite with amorphous C. By modification of the chemical stability of the carbide phase, the addition of Ni was found to strongly promote the formation of amorphous carbon phase in the coatings. Samples have been microstructurally analyzed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Mechanical properties have been evaluated through nanoindentation and pin-on-disc measurements; electrical properties were determined by measurement of the resistivity and the contact resistance. Alloyed nanocomposite coatings were also found to exhibit enhanced tribological and electrical properties, with a decreased resistivity and friction. This makes these thin films very interesting for application in sliding electrical contacts. The mechanisms responsible for the reductions remain to be determined.

    National Category
    Inorganic Chemistry Engineering and Technology
    Research subject
    Chemistry with specialization in Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-109034 (URN)10.1039/c0jm00592d (DOI)000279565900025 ()
    Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
    8. Friction and contact resistance of nanocomposite Ti-Ni-C coatings
    Open this publication in new window or tab >>Friction and contact resistance of nanocomposite Ti-Ni-C coatings
    2011 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 270, no 9-10, p. 555-566Article in journal (Refereed) Published
    Abstract [en]

    Ceramic nanocomposite coatings in the Ti-Ni-C were deposited using PVD and studied with respect to tribological properties and contact resistance. It was shown that coatings could be deposited combining of a low contact resistance and a low friction coefficient against silver, making them suitable for use in high performance electrical contacts.Nine coatings with different amounts of C and Ni were deposited. Coatings on flat Ni plated copper substrates were tested in a tribological ball-on-disc setup against ball bearing steel balls. Depending on primarily the amount of carbon the coatings showed very different friction coefficient and wear rate. The coatings were also deposited on cylindrical Ni plated copper substrates. Using geometrically identical silver plated cylinders as counter surface these were evaluated in a test setup better resembling a real life electrical contact. For most coatings a low electrical contact resistance was measured. The evolution of friction coefficient and contact resistance was correlated to wear marks and contact tracks, with their generated tribofilms, as examined after testing using electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy.

    Keywords
    TiC, TiNiC, Friction, Tribofilm, Electrical contacts, Contact resistance
    National Category
    Inorganic Chemistry Engineering and Technology
    Research subject
    Inorganic Chemistry; Engineering Science with specialization in Materials Science
    Identifiers
    urn:nbn:se:uu:diva-109425 (URN)10.1016/j.wear.2010.12.006 (DOI)000290132500001 ()
    Available from: 2009-10-15 Created: 2009-10-15 Last updated: 2017-12-12
    9. Carbide and nanocomposite thin films in the Ti-Pt-C system
    Open this publication in new window or tab >>Carbide and nanocomposite thin films in the Ti-Pt-C system
    Show others...
    2010 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 518, no 18, p. 5104-5109Article in journal (Refereed) Published
    Abstract [en]

    Thin films in the Ti-Pt-C system were deposited by non-reactive, DC-magnetron sputtering. Samples were characterised using X-ray photoelectron spectroscopy, X-ray diffraction, and transmission electron microscopy. A previously not reported metastable solid solution carbide, (Ti1-xPtx)C-y with a Pt/Ti ratio of up to 0.43 was observed. This solid solution phase was present both as single phase in polycrystalline samples, and together with amorphous carbon (a-C) in nanocomposite samples. Annealing of nanocomposite samples leads to the decomposition of the solid solution phase and the formation of a nc-TiCx/a-C/nc-Pt nanocomposite. Test sensors for automotive gas exhausts manufactured from such a three-phase material suffer from complete oxidation of the coating at 400 degrees C with no observed sensor activity.

    Place, publisher, year, edition, pages
    Elsevier B.V., 2010
    Keywords
    Solid solution carbide, Nanocomposite, Sputtering, Gas sensor; Annealing, Transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction
    National Category
    Inorganic Chemistry
    Research subject
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-109234 (URN)10.1016/j.tsf.2010.03.017 (DOI)000279659900013 ()
    Available from: 2009-10-12 Created: 2009-10-12 Last updated: 2017-12-12Bibliographically approved
  • 221.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Synthesis and characterisation of compositionally complex coatings: Invited presentation2016Conference paper (Other academic)
    Abstract [en]

    There is a clear tendency in the materials research to move towards more compositionally complexmaterials, using more elements in a single coating material. This is true both for entire structures,such as multi-layer coatings, but also single layers. The presentation will focus on the latter, and thechallenges such materials pose both from a synthesis / process point of view, and from a materialsanalysis point of view. Examples of such materials are complex solid solution phases, such as Cr-Al-O-N and Al-Ge-O-N, but also new classes of materials such as the high-entropy / concentratedsolid solution alloys and their nitrides, carbides and oxides.Synthesis using reactive sputter deposition offers many different possibilities to deposit multicomponentcoatings, with different types of targets (elemental, segmented, composite, alloy,compound, and powder), as well as different process modifications (dc, pulsed dc, HiPIMS, etc)and also the possibility to use one or several reactive gases. All this will influence the processes atthe target, the transport to the substrate, as well as the growth of the coating. The presentation willguide you through some basic concepts of attaining compositional control of your material, andexamples of what kind of pit-falls to avoid, and discuss the importance of understanding theatomistic processes from target to coating.From the above paragraph it is understood that it will never be obvious what is actually deposited.Therefore careful analysis of the deposited material will always be needed. This includes elementcomposition data, chemical bonding as well as structural information, which all becomes moredifficult to extract and interpret as the number of elements in the material increases. ¬Thepresentation will present some of the challenges that multi-component coatings give rise to, anddiscuss possible methods to overcome them.Examples will to a large extent be taken from the presenter’s recent research into quaternaryoxynitride materials based on AlN and high-entropy nitrides, but also from relevant literature.

  • 222.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Transparent AlN-based nitride films: keynote lecture2016Conference paper (Other academic)
    Abstract [en]

    The lecture will give an overview of recent research on AlN-based thin film materials.Focus of the lecture will be on coating structure / microstructure, the materialproperties, and their correlations. AlN is a well-known wide band gap semiconductorwhich is transparent into the UV-range. By alloying AlN new materials with modifiedoptical, mechanical and electrical properties can be attained. The alloying can lead tothree types of coating structures: solid solution phases where the alloying elementsubstitutes Al or N in the wurzite type AlN structure; nanocomposites where thealloying leads to the formation of a second phase and a two-phase microstructure; ortotally amorphous or glass-like materials. What is formed will depend on the alloyingelements, their concentrations, and the growth conditions.Specifically, structure and properties of AlN-based coatings alloyed in two directionswill be presented: alloying with group 14 elements (Si, Ge, or Sn), and with oxygen.By this double alloying, producing quaternary oxynitride materials, a wide range ofmechanical and optical properties becomes attainable, e.g. achieving hardnesses upto 32 GPa, and a continuously variable optical band gap between 2.5 and 6.9 eV.Such properties could e.g. be utilised in protective optical coatings with tuneableabsorption or decorative coating.Coatings were deposited by reactive magnetron sputtering, using elemental targetsand varied ratios of the three process gases Ar, N2 and O2. Deposition was generallycarried out at low temperatures to allow formation of metastable solid solution phases.Coatings have been characterised using mainly X-ray diffraction (XRD), photoelectronspectroscopy (XPS) and scanning electron microscopy. Optical and mechanicalproperties have been evaluated using nanoindentation and UV-vis spectroscopy.

  • 223.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    X-ray photoelectron spectroscopy: Invited lecture2017Conference paper (Other academic)
  • 224.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    X-ray photoelectron spectroscopy: Invited lecture2016Conference paper (Other (popular science, discussion, etc.))
  • 225.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    André, Benny
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Urbonaite, Sigita
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Wiklund, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Synthesis, structure and properties of Ni-alloyed TiCx-based thin films2010In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 20, no 28, p. 5950-5960Article in journal (Refereed)
    Abstract [en]

    By using non-reactive sputter deposition at low temperatures metastable solid solution phases in the Ti–Ni–C system were synthesized. Produced thin films were either single phase carbides or nanocomposite of nanocrystalline carbide and amorphous C. In the Ni-containing samples a supersaturated solid solution phase (Ti1−xNix)Cy was identified, and was present either as single phase or in a nanocomposite with amorphous C. By modification of the chemical stability of the carbide phase, the addition of Ni was found to strongly promote the formation of amorphous carbon phase in the coatings. Samples have been microstructurally analyzed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Mechanical properties have been evaluated through nanoindentation and pin-on-disc measurements; electrical properties were determined by measurement of the resistivity and the contact resistance. Alloyed nanocomposite coatings were also found to exhibit enhanced tribological and electrical properties, with a decreased resistivity and friction. This makes these thin films very interesting for application in sliding electrical contacts. The mechanisms responsible for the reductions remain to be determined.

  • 226.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Buchholt, Kristina
    Lu, Jun
    Hultman, Lars
    Lloyd Spetz, Annika
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Carbide and nanocomposite thin films in the Ti-Pt-C system2010In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 518, no 18, p. 5104-5109Article in journal (Refereed)
    Abstract [en]

    Thin films in the Ti-Pt-C system were deposited by non-reactive, DC-magnetron sputtering. Samples were characterised using X-ray photoelectron spectroscopy, X-ray diffraction, and transmission electron microscopy. A previously not reported metastable solid solution carbide, (Ti1-xPtx)C-y with a Pt/Ti ratio of up to 0.43 was observed. This solid solution phase was present both as single phase in polycrystalline samples, and together with amorphous carbon (a-C) in nanocomposite samples. Annealing of nanocomposite samples leads to the decomposition of the solid solution phase and the formation of a nc-TiCx/a-C/nc-Pt nanocomposite. Test sensors for automotive gas exhausts manufactured from such a three-phase material suffer from complete oxidation of the coating at 400 degrees C with no observed sensor activity.

  • 227.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Gorgoi, Mihaela
    Schäfers, Franz
    Svensson, Svante
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Surface and Interface Science.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Influence of sputter damage on the XPS analysis of metastable nanocomposite coatings2009In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 204, no 4, p. 455-462Article in journal (Refereed)
    Abstract [en]

    X-ray photoelectron spectroscopy (XPS) is a standard method of determining chemical bonding in e.g. nanocomposites. We demonstrate that sputter-cleaning of the sample prior to analysis can substantially alter the attained information. We present an in-depth analysis of sputter damage on binary and ternary TiC-based coatings in the Ti–Ni–C system. XPS was performed after sputter etching with different ion energies (0.15–4 keV). Results are compared to data from the bulk of undamaged samples attained using high kinetic energy XPS. We observe substantial sputter damage, strongly dependent on sputter energies and coating stability. Metastable samples exhibit severe sputter damage after etching with 4 keV. Additional samples from other Ti–Me–C (Me = Al, Fe, Cu or Pt) systems were also examined, and notable sputter damage was observed. This suggests that accurate analysis of any metastable nanocomposite requires careful consideration of sputter damages.

  • 228.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Gorgoi, M
    Schäfers, F
    Svensson, S
    Influence of sputter damage on the XPS analysis of metastable nanocomposite coatings2009Conference paper (Refereed)
  • 229.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Joelsson, T
    André, B
    Ljungcrantz, H
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Industrialisation study of nanocomposite coatings for electrical contact applications2008Conference paper (Refereed)
  • 230.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Johansson, E
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Sandell, A
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Gorgoi, M
    Schäfers, F
    Braun, W
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Stüber, M
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Svensson, S
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Eberhardt, W
    HIKE experiments at KMC-1: Recent Analysis of Thin Film Nanocomposites2007In: Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung m.b.H. (BESSY) Annual Report (2006), p. 503-504Article in journal (Other academic)
  • 231.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Olsson, Erik
    André, Benny
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Joelsson, Torbjörn
    Öberg, Åke
    Wiklund, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Ljungcrantz, Henrik
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Industrialisation Study of Nanocomposite nc-TiC/a-C Coatings for Electrical Contact Applications2009In: Plasma Processes and Polymers, ISSN 1612-8850, Vol. 6, no S1, p. S928-S934Article in journal (Refereed)
    Abstract [en]

    Nanocomposite nc-TiC/a-C coatings were prepared by non-reactive magnetron sputtering in industrial scale equipment, under varying deposition conditions in order to investigate upscaling and possible industrialisation. The coatings were found to have similar microstructure and performance compared to previous laboratory scale experiments. The samples were characterised with XRD, XPS and SEM as well with ball-on-disc, nanoindentation and electrical measurements. Coatings containing a small fraction of a-C matrix phase were found to have promising both electrical properties (rho < 400 mu Omega cm and contact resistances down to 0.34 m Omega at 40 N) and tribological properties (f < 0.3 for 10 000 laps).

  • 232.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Persson, P.O.Å
    Lattermann, M
    Stüber, M
    Gorgoi, M
    Sandell, A
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Ziebert, C
    Schäfers, F
    Braun, W
    Halbritter, J
    Ulrich, S
    Eberhard, W
    Hultman, L
    Siegbahn, H
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Svensson, S
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    On the origin of a third spectral component of C1s XPS-spectra for nc-TiC/a-C nanocomposite thin films2008In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 202, no 15, p. 3563-3570Article in journal (Refereed)
    Abstract [en]

    X-ray photoelectron spectroscopy (XPS) spectra of sputter-etched nc-TiC/a-C nanocomposite thin films published in literature show an extra feature of unknown origin in the C1s region. This feature is situated between the contributions of carbide and the carbon matrix. We have used high kinetic energy XPS (HIKE-XPS) on magnetron-sputtered nc-TiC/a-C thin films to show that this feature represents a third chemical environment in the nanocomposites, besides the carbide and the amorphous carbon. Our results show that component is present in as-deposited samples, and that the intensity is strongly enhanced by Ar+-ion etching. This third chemical environment may be due to interface or disorder effects. The implications of these observations on the XPS analysis of nanocomposites are discussed in the light of overlap problems for ternary carbon based systems.

  • 233.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Råsander, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Klintenberg, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Bergman, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Eriksson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Design of the Lattice Parameter of Embedded Nanoparticles2010In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 496, no 1-3, p. 95-99Article in journal (Refereed)
    Abstract [en]

    It is found that the bonding of nanoparticles in nancomposites can be influenced by interactions with a surrounding matrix phase. A model involving charge transfer between phases is presented, and supported by DFT-simulations. The model explains observations in nanocomposite nc-TiCx/a-C of additional interface states and lattice expansion of TiCx. It is suggested that this approach can be extended to other types of nanocomposites, and that it opens for new possibilities in materials design.

  • 234.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorgansik kemi.
    Wilhelmsson, Ola
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    A Contact Element and a Contact Arrangement2007Patent (Other (popular scientific, debate etc.))
  • 235.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Wilhelmsson, Ola
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Nanocomposite nc-MeC/a-C thin films for electrical contact applications2006Conference paper (Refereed)
  • 236.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Wilhelmsson, Ola
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Nanocomposite nc-TiC/a-C thin films for electrical contact applications2006In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 100, no 5, p. 054303-Article in journal (Refereed)
    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.

  • 237.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Wilhelmsson, Ola
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Lindquist, M
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Wiklund, U
    Råsander, M
    Sanyal, B
    Eriksson, O
    Microstructural design of ternary nc-TiC/a-C based nanocomposite coatings through alloying with a second metallic element2008Conference paper (Refereed)
  • 238.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Wilhelmsson, Ola
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Lindquist, M
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Wiklund, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Råsander, M
    Sanyal, B
    Eriksson, O
    Design of sputtered nc-MeC/a-C nanocomposite coatings through doping with a second metallic element2007Conference paper (Refereed)
  • 239.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Wilhelmsson, Ola
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry. oorganisk kemi. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Lindquist, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Wiklund, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Råsander, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Sanyal, Biplab
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Eriksson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Concept of designing sputtered low-friction nanocomposite coatings through doping2007In: IVC-17/ICSS-13 (Stockholm 2 - 6 juli) Presented orally, 2007Conference paper (Other (popular science, discussion, etc.))
  • 240.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Wilhelmsson, Ola
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Steuber, M
    Halbritter, J
    Ziebert, C
    Ulrich, S
    Schild, D
    Discussion of a possible third carbon bonding state in PVD-deposited metal carbide / amorphous carbon nanocomposite thin films and its impact on mechanical and electrical properties2006Conference paper (Refereed)
  • 241.
    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 University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    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 University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Gao, Xindong
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Boman, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    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 University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Ink-jet printed thin-film transistors with carbon nanotube channels shaped in long strips2011In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 109, no 8, p. 084915-Article in journal (Refereed)
    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.

  • 242.
    Liljegren, G
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry.
    Nyholm, Leif
    Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Electrochemically Controlled Solid Phase Microextraction and Preconcentration using Polypyrrole Coated Microarray Electrodes in a Flow System2003In: presented at the 26th International Symposium on Capillary Chromatography & Electrophoresis, Las Vegas, USA, May 18-22, 2003, 2003Conference paper (Refereed)
  • 243.
    Liljegren, Gustav
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Dahlin, Andreas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Zettersten, Camilla
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Bergquist, Jonas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Nyholm, Leif
    Department of Materials Chemistry, Inorganic Chemistry. Oorganisk kemi.
    On-line coupling of a microelectrode array equipped poly(dimethylsiloxane) microchip with an integrated graphite electrospray emitter for electrospray ionisation mass spectrometry2005In: Lab on a Chip, no 5, p. 1008-1016Article in journal (Refereed)
    Abstract [en]

    A novel method for the manufacturing of microchips for on-chip combinations of electrochemistry (EC) and sheathless electrospray ionisation mass spectrometry (ESI-MS) is described. The technique, which does not require access to clean-room facilities, is based on the incorporation of an array of gold microcoil electrodes into a poly(dimethylsiloxane) (PDMS) microflow channel equipped with an integrated graphite based sheathless ESI emitter. Electrochemical measurements, which were employed to determine the electroactive area of the electrodes and to test the microchips, show that the manufacturing process was reproducible and that the important interelectrode distance in the electrochemical cell could to be adequately controlled. The EC-ESI-MS device was evaluated based on the ESI-MS detection of the oxidation products of dopamine. The results demonstrate that the present on-chip approach enables full potentiostatic control of the electrochemical cell and the attainment of very short transfer times between the electrochemical cell and the electrospray emitter. The transfer times were 0.6 and 1.2 s for flow rates of 1.0 and 0.5 uL min-1, respectively, while the electrochemical conversion efficiency of the electrochemical cell was found to be 30% at a flow rate of 0.5 uL min-1. To decouple the electrochemical cell from the ESI-MS high voltage and to increase the user-friendliness, the on-line electrochemistry-ESI-MS experiments were performed using a wireless Bluetooth battery-powered instrument with the chip floating at the potential induced by the ESI high voltage. The described on-chip EC-ESI-MS device can be used for fundamental electrochemical investigations as well as for applications based on the use of electrochemically controlled sample pretreatment, preconcentration and ionisation steps prior to ESI-MS.

  • 244.
    Liljegren, Gustav
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Forsgard, Niklas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Zettersten, Camilla
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Pettersson, Jean
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Svedberg, Malin
    Herranen, Merja
    Department of Materials Chemistry, Inorganic Chemistry. Oorganisk kemi.
    Nyholm, Leif
    Department of Materials Chemistry, Inorganic Chemistry. Oorganisk kemi.
    On-line electrochemically controlled solid-phase extraction interfaced to electrospray and inductively coupled plasma mass spectrometry2005In: The Analyst, no 130, p. 1358-1368Article in journal (Refereed)
    Abstract [en]

    Electrochemically controlled solid-phase extractions of anions were interfaced on-line to electrospray mass spectrometry (ESI-MS) and inductively coupled plasma mass spectrometry (ICP-MS), using polypyrrole coated electrodes and a thin-layer electrochemical (EC) flow cell. The results indicate that electrochemically controlled solid-phase extraction (EC-SPE) can be used as a versatile potential controlled sample preparation technique for a range of anions and that the properties of the polypyrrole coatings can be modified by altering the electrodeposition conditions. In the present study, the influence of interfering anions (i.e., fluoride and sulfate), and the anion used during the electropolymerisation, on the bromide extraction recovery was investigated for EC-SPE interfaced to ICP-MS. The results of these experiments show that the interference due to the presence of similar concentrations of sulfate can be reduced when using a polypyrrole coating electropolymerised in the presence of bromide ions. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) measurements were also used to study the morphology of the coatings, as well as the variations in the film thickness within the coatings. The effect of different desorption techniques on the bromide preconcentration factor in the ICP-MS on-line flow system was also examined. Stopped-flow desorption was found to give rise to significantly increased preconcentration factors in comparison with desorptions in flowing solutions. While the desorption efficiency depends on the type of desorption electrolyte (the electrolyte in which the desorption takes place), due to the competing influx of cations, the influence of the pH on the switching charge of the polypyrrole coating was found to be small, at constant ionic strength. To study the applicability of the EC-SPE technique with respect to real samples, investigations were also made with tap water samples spiked with different bromide concentrations. The results of these experiments, which were carried out using a modified thin-layer EC flow cell allowing in situ polymerisation of polypyrrole yielding a polymer plug covering the cross section of the channel, demonstrate that 3 uM concentrations of bromide could be detected in the tap water sample. This demonstrates that the extraction technique allows extractions of low concentrations of ions in the presence of significantly higher concentrations of other similar ions. The fact that the extraction and desorption steps are electrochemically controlled makes EC-SPE particularly well suited for inclusion in miniaturised lab-on-a-chip systems.

  • 245. Lima, Nicola
    et al.
    Caneschi, Andrea
    Gatteschi, Dante
    Kritikos, Mikael
    Westin, Gunnar
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Validity of the Classical Monte Carlo Method To Model the Magnetic Properties of a Large Transition-Metal Cluster: Mn192006In: Inorganic Chemistry, Vol. 45, no 6, p. 2391-2393Article in journal (Refereed)
    Abstract [en]

    The susceptibility of the large transition-metal cluster [Mn19O12(MOE)14(MOEH)10]·MOEH (MOE = OC2H2O-CH3) has been fitted through classical Monte Carlo simulation, and an estimation of the exchange coupling constants has been done. With these results, it has been possible to perform a full-matrix diagonalization of the cluster core, which was used to provide information on the nature of the low-lying levels.

  • 246.
    Lindahl, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Thin Film Synthesis of Nickel Containing Compounds2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Most electrical, magnetic or optical devices are today based on several, usually extremely thin layers of different materials.  In this thesis chemical synthesis processes have been developed for growth of less stable and metastable layers, and even multilayers, of nickel containing compounds.

    A chemical vapor deposition (CVD) method for deposition of metastable Ni3N has been developed.  The deposition process employs ammonia as nitrogen precursor. An atomic layer deposition (ALD) process for deposition of both polycrystalline and epitaxial NiO and using low oxygen activity, has also been developed. Both deposition processes utilizes bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II) (Ni(thd)2) as the metal precursor. The Ni3N deposition proceeds via surface reactions. The growth rate is very sensitive to the partial pressure of ammonia, why adsorbed –NHx species are believed to be of importance for the film growth. Similar reactions can be expected between the metal precursor and H2O. For ALD of NiO a large excess of water was needed

    For the multilayered structures of Ni3N/NiO, growth processes, working at low activities of oxygen and hydrogen, are needed to avoid oxidation or reduction of the underlying layer. Chemical vapor growth methods such as CVD and ALD are often suffering from using high activities of hydrogen or oxygen to deposit metals and oxides. An alternative deposition pathway for metal deposition, without any hydrogen in the vapor, has been demonstrated. The metal has been formed by decomposition of the metastable nitride Ni3N in a post-annealing process.  Ni3N decomposes via different mechanisms, depending on environment in the annealing process. The different mechanisms result in different degrees of ordering in the resulting Ni films. From the knowledge gained about the chemical growth of NiO and Ni3N as well as the decomposition of Ni3N, well-defined multilayer structures have been produced in different combinations of NiO, Ni3N and Ni.

    List of papers
    1. Chemical Vapour Deposition of Metastable Ni3N
    Open this publication in new window or tab >>Chemical Vapour Deposition of Metastable Ni3N
    2009 (English)In: EuroCVD17/CVD17, The Electrochemical Society , 2009, Vol. 25, no 8, p. 365-372Conference paper, Published paper (Refereed)
    Place, publisher, year, edition, pages
    The Electrochemical Society, 2009
    National Category
    Inorganic Chemistry
    Research subject
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-111453 (URN)10.1149/1.3207614 (DOI)978-1-60768-095-6 (ISBN)
    Conference
    EuroCVD17/CVD17
    Available from: 2009-12-15 Created: 2009-12-15 Last updated: 2009-12-22Bibliographically approved
    2. An in-situ study of nickel formation upon decomposition of nickel nitride films
    Open this publication in new window or tab >>An in-situ study of nickel formation upon decomposition of nickel nitride films
    (English)In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559Article in journal (Refereed) Submitted
    National Category
    Inorganic Chemistry
    Research subject
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-111454 (URN)
    Available from: 2009-12-15 Created: 2009-12-15 Last updated: 2017-12-12Bibliographically approved
    3. Atomic Layer Deposition of NiO by the Ni(thd)2/H2O Precursor Combination
    Open this publication in new window or tab >>Atomic Layer Deposition of NiO by the Ni(thd)2/H2O Precursor Combination
    2009 (English)In: Chemical Vapor Deposition, ISSN 0948-1907, E-ISSN 1521-3862, Vol. 15, no 7-9, p. 186-191Article in journal (Refereed) Published
    Abstract [en]

    Polycrystalline nickel oxide is deposited on SiO2 substrates by   alternating pulses of   bis(2,2,6,6-tetramethylheptane-3,5-dionato)nickel(II) (Ni(thd)(2)) and   H2O. The deposition process shows atomic layer deposition (ALD)   characteristics with respect to the saturation behavior of the two   precursors at deposition temperatures up to 275 degrees C. The growth   of nickel oxide is shown to be highly dependent on surface hydroxide   groups, and a large excess of H2O is required to achieve saturation.   Throughout the deposition temperature range the amount of carbon in the   film, originating from the metal precursor ligand, is in the range   1-2%. Above 275 degrees C ALD growth behavior is lost in favor of   thermal decomposition of the metal precursor. The initial nucleation   process is studied by atomic force microscopy (AFM) and reveals   nucleation of well-separated grains which coalesce to a continuous film   after about 250 ALD cycles.

    Place, publisher, year, edition, pages
    WILEY, 2009
    Keywords
    ALD, growth rate, morphology, nickel oxide, Ni(thd)(2)
    National Category
    Chemical Sciences
    Research subject
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-111451 (URN)10.1002/cvde.200906762 (DOI)000270343800005 ()
    Available from: 2009-12-15 Created: 2009-12-15 Last updated: 2017-12-12Bibliographically approved
    4. Epitaxial NiO(100) and NiO(111) films grown by atomic layer deposition
    Open this publication in new window or tab >>Epitaxial NiO(100) and NiO(111) films grown by atomic layer deposition
    2009 (English)In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 311, no 16, p. 4082-4088Article in journal (Refereed) Published
    Abstract [en]

    Epitaxial NiO (1 1 1) and NiO (1 0 0) films have been grown by atomic   layer deposition on both MgO (1 0 0) and alpha-Al2O3 (0 0 1) substrates   at temperatures as low as 200 degrees C by using   bis(2,2,6,6-tetramethyl-3,5-heptanedionato)Ni(II) and water as   precursors. The films grown on the MgO (1 0 0) substrate show the   expected cube on cube growth while the NiO (1 1 1) films grow with a   twin rotated 180 degrees on the alpha-Al2O3 (0 0 1) substrate surface.   The films had columnar microstructures on both substrate types. The   single grains were running throughout the whole film thickness and were   significantly smaller in the direction parallel to the surface. Thin   NiO (1 1 1) films can be grown with high crystal quality with a FWHM of   0.02-0.05 degrees in the rocking curve measurements.

    Place, publisher, year, edition, pages
    Elsevier, 2009
    Keywords
    Atomic layer deposition, X-ray diffraction, Transmission electron microscopy, NiO (100), NiO (111), Crystallite size
    National Category
    Chemical Sciences Engineering and Technology
    Research subject
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-111450 (URN)10.1016/j.jcrysgro.2009.06.030 (DOI)000269580100018 ()
    Available from: 2009-12-15 Created: 2009-12-15 Last updated: 2017-12-12Bibliographically approved
    5. Growth and stability of CVD Ni3N and ALD NiO dual layers
    Open this publication in new window or tab >>Growth and stability of CVD Ni3N and ALD NiO dual layers
    2010 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 205, no 3, p. 710-716Article in journal (Refereed) Published
    National Category
    Inorganic Chemistry
    Research subject
    Chemistry with specialization in Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-111456 (URN)10.1016/j.surfcoat.2010.07.059 (DOI)000282997400004 ()
    Available from: 2009-12-15 Created: 2009-12-15 Last updated: 2017-12-12Bibliographically approved
  • 247.
    Lindahl, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Lu, Jun
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microstructure Laboratory.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Carlsson, Jan-Otto
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Epitaxial NiO(100) and NiO(111) films grown by atomic layer deposition2009In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 311, no 16, p. 4082-4088Article in journal (Refereed)
    Abstract [en]

    Epitaxial NiO (1 1 1) and NiO (1 0 0) films have been grown by atomic   layer deposition on both MgO (1 0 0) and alpha-Al2O3 (0 0 1) substrates   at temperatures as low as 200 degrees C by using   bis(2,2,6,6-tetramethyl-3,5-heptanedionato)Ni(II) and water as   precursors. The films grown on the MgO (1 0 0) substrate show the   expected cube on cube growth while the NiO (1 1 1) films grow with a   twin rotated 180 degrees on the alpha-Al2O3 (0 0 1) substrate surface.   The films had columnar microstructures on both substrate types. The   single grains were running throughout the whole film thickness and were   significantly smaller in the direction parallel to the surface. Thin   NiO (1 1 1) films can be grown with high crystal quality with a FWHM of   0.02-0.05 degrees in the rocking curve measurements.

  • 248.
    Lindahl, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Carlsson, Jan-Otto
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    An in-situ study of nickel formation upon decomposition of nickel nitride filmsIn: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559Article in journal (Refereed)
  • 249.
    Lindahl, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Carlsson, Jan-Otto
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Atomic Layer Deposition of NiO by the Ni(thd)2/H2O Precursor Combination2009In: Chemical Vapor Deposition, ISSN 0948-1907, E-ISSN 1521-3862, Vol. 15, no 7-9, p. 186-191Article in journal (Refereed)
    Abstract [en]

    Polycrystalline nickel oxide is deposited on SiO2 substrates by   alternating pulses of   bis(2,2,6,6-tetramethylheptane-3,5-dionato)nickel(II) (Ni(thd)(2)) and   H2O. The deposition process shows atomic layer deposition (ALD)   characteristics with respect to the saturation behavior of the two   precursors at deposition temperatures up to 275 degrees C. The growth   of nickel oxide is shown to be highly dependent on surface hydroxide   groups, and a large excess of H2O is required to achieve saturation.   Throughout the deposition temperature range the amount of carbon in the   film, originating from the metal precursor ligand, is in the range   1-2%. Above 275 degrees C ALD growth behavior is lost in favor of   thermal decomposition of the metal precursor. The initial nucleation   process is studied by atomic force microscopy (AFM) and reveals   nucleation of well-separated grains which coalesce to a continuous film   after about 250 ALD cycles.

  • 250.
    Lindahl, Erik
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    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
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