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  • 1.
    Li, Youbing
    et al.
    Engineering Laboratory of Advanced Energy Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Zhejiang, Ningbo, 315201, China; Qianwan Institute of CNiTECH, Ningbo, 315336, China.
    Zhu, Shuairu
    Zhejiang Institute of Tianjin University, 85 Zhongguan West Road, Ningbo, 315201, Zhejiang, China.
    Le, Jia-Bo
    Key Laboratory of Advanced Fuel Cell and Electrolyzer Technology of Zhejiang Province, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Wang, Xue
    Key Laboratory of Advanced Fuel Cell and Electrolyzer Technology of Zhejiang Province, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.
    Chen, Lu
    Engineering Laboratory of Advanced Energy Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Zhejiang, Ningbo, 315201, China; Qianwan Institute of CNiTECH, Ningbo, 315336, China.
    Ding, Haoming
    Engineering Laboratory of Advanced Energy Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Zhejiang, Ningbo, 315201, China; Qianwan Institute of CNiTECH, Ningbo, 315336, China.
    Chen, Ke
    Engineering Laboratory of Advanced Energy Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Zhejiang, Ningbo, 315201, China; Qianwan Institute of CNiTECH, Ningbo, 315336, China.
    Li, Mian
    Engineering Laboratory of Advanced Energy Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Zhejiang, Ningbo, 315201, China; Qianwan Institute of CNiTECH, Ningbo, 315336, China.
    Du, Shiyu
    Engineering Laboratory of Advanced Energy Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Zhejiang, Ningbo, 315201, China; Qianwan Institute of CNiTECH, Ningbo, 315336, China.
    Wang, Hui
    Zhejiang Institute of Tianjin University, 85 Zhongguan West Road, Ningbo, 315201, Zhejiang, China.
    Zhang, Runnan
    Zhejiang Institute of Tianjin University, 85 Zhongguan West Road, Ningbo, 315201, Zhejiang, China.
    Persson, Per O. Å.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Kuang, Yongbo
    Key Laboratory of Advanced Fuel Cell and Electrolyzer Technology of Zhejiang Province, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China; Center of Materials Science and Optoelectronics Engineering, University of the Chinese Academy of Sciences, 19(A) Yuquan Road, Beijing, 100049, China.
    Chai, Zhifang
    Engineering Laboratory of Advanced Energy Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Zhejiang, Ningbo, 315201, China; Qianwan Institute of CNiTECH, Ningbo, 315336, China.
    Huang, Qing
    Engineering Laboratory of Advanced Energy Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Zhejiang, Ningbo, 315201, China; Qianwan Institute of CNiTECH, Ningbo, 315336, China.
    A-site alloying-guided universal design of noble metal-based MAX phases2024Ingår i: Matter, ISSN 2590-2393, E-ISSN 2590-2385, Vol. 7, nr 2, s. 523-538Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mn+1AXn (MAX) phases have attracted significant attention due to their structural diversity and potential applications. Designing MAX phases with single-atom-thick A layers featuring 4d/5d-orbital electronic elements is interesting work. Here, we present a comprehensive report on noble metal-based M2(A1-xA′x)C (M = V, Ti, Nb; A = Al, Sn, In, Ga, Ge; A′ = Ru, Rh, Pd, Ir, Pt, Au and combinations thereof; 0 < x ≤ 0.4) phases featuring A sublayers of 4d/5d-orbital electronic elements through an A-site alloying strategy. The chemical composition of MAX phases can be adjusted by selecting different M- and A-site elements, with morphology tailored by distinct C sources. Furthermore, the V2(Sn0.8Pt0.2)C (15.7 wt % Pt) catalyst showed better performance for hydrogen evolution reaction compared to the commercial Pt/C (20 wt % Pt) electrode. This study highlights the prospects of A-site alloying for the design of novel MAX phases with unique properties and promising applications in electrocatalysis and beyond.

    Publikationen är tillgänglig i fulltext från 2025-01-10 14:32
  • 2.
    Nzulu, Gabriel Kofi
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Högberg, Hans
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Nude, Prosper M.
    University of Ghana, Accra, Ghana.
    Yaya, Abu
    University of Ghana, Accra, Ghana.
    Magnuson, Martin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Chemical Reactivity and Alteration of Pyrite Mineral in the Kubi Gold Concession in Ghana2024Ingår i: Mining, Metallurgy & Exploration, ISSN 2524-3462Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Pyrite is the most common among the group of sulfide minerals in the Earth and abundant in most geological settings. This gangue mineral in association with garnet, hematite, magnetite, and other sulfide minerals acts as an indicator mineral in the Kubi concession of the Asante Gold corporation in Ghana. X-ray diffraction (XRD), air annealing in a furnace, energy-dispersive x-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) were applied to investigate the crystal structure, identify individual elements, permanence, transformation, and chemical/electronic properties of such pyrite. The study aims to identify individual elements and to gain an understanding of the surface reaction mechanisms, as well as the properties of precipitated pyrite particles observed during the hydrothermal formation of the ore deposit. XRD shows that pristine and annealed samples contain some hematite and quartz besides pyrite. Results from air annealing indicate that the relationship between pyrite and hematite-magnetite is controlled by temperature. EDX reveals that the sample has O and C as contaminants, while XPS in addition reveals Ba, Au, P, Al, and N. These elements are attributed to pyrite that bonds metallically or covalently to neighboring ligands/impurity minerals such as oxides, chalcogenide sulfides, as well as the gangue alteration minerals of magnetite and hematite in the pyrite sample.

    These findings suggest that during the hydrothermal flow regime, pyrite, pathfinder elements, and impurity minerals/metals were in contact with quartz minerals before undergoing hematite transformation, which thus becomes an indicator mineral in the Kubi gold concession.

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  • 3.
    Nzulu, Gabriel Kofi
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Högberg, Hans
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Nude, Prosper M.
    Univ Ghana, Ghana.
    Yaya, Abu
    Univ Ghana, Ghana.
    Magnuson, Martin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Correction: Chemical Reactivity and Alteration of Pyrite Mineral in the Kubi Gold Concession in Ghana (27 Feb, 10.1007/s42461-024-00932-4, 2024)2024Ingår i: MINING METALLURGY & EXPLORATION, ISSN 2524-3462Artikel i tidskrift (Övrigt vetenskapligt)
  • 4.
    Pela, Ronaldo Rodrigues
    et al.
    Zuse Inst Berlin ZIB, Germany.
    Hsiao, Ching-Lien
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Gueorguiev, Gueorgui Kostov
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Electronic and optical properties of core-shell InAlN nanorods: a comparative study <i>via</i> LDA, LDA-1/2, mBJ, HSE06, <i>G</i><sub>0</sub><i>W</i><sub>0</sub> and BSE methods2024Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Currently, self-induced InAlN core-shell nanorods enjoy an advanced stage of accumulation of experimental data from their growth and characterization as well as a comprehensive understanding of their formation mechanism by the ab initio modeling based on Synthetic Growth Concept. However, their electronic and optical properties, on which most of their foreseen applications are expected to depend, have not been investigated comprehensively. GW and the Bethe-Salpeter equation (BSE) are regarded as the state-of-the-art ab initio methodologies to study these properties. However, one of the major drawbacks of these methods is the computational cost, much higher than density-functional theory (DFT). Therefore, in many applications, it is highly desirable to answer the question of how well approaches based on DFT, such as e.g. the local density approximation (LDA), LDA-1/2, the modified Becke-Johnson (mBJ) and the Heyd-Scuseria-Ernzerhof (HSE06) functionals, can be employed to calculate electronic and optical properties with reasonable accuracy. In the present paper, we address this question, investigating how effective the DFT-based methodologies LDA, LDA-1/2, mBJ and HSE06 can be used as approximate tools in studies of the electronic and optical properties of scaled down models of core-shell InAlN nanorods, thus, avoiding GW and BSE calculations.

  • 5.
    Pingen, Katrin
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Fraunhofer Inst Organ Elect, Germany; Tech Univ Dresden, Germany.
    Hinz, Alexander M.
    Fraunhofer Inst Organ Elect, Germany; Tech Univ Dresden, Germany.
    Sandström, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Wolff, Niklas
    Univ Kiel, Germany; Univ Kiel, Germany.
    Kienle, Lorenz
    Univ Kiel, Germany; Univ Kiel, Germany.
    Scipioni, Larry
    PVD Prod Inc, MA 01887 USA.
    Greer, James
    PVD Prod Inc, MA 01887 USA.
    von Hauff, Elizabeth
    Fraunhofer Inst Organ Elect, Germany; Tech Univ Dresden, Germany.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hsiao, Ching-Lien
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    High growth rate magnetron sputter epitaxy of GaN using a solid Ga target2024Ingår i: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 220, artikel-id 112852Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Magnetron sputter epitaxy (MSE) is a promising processing route for group-III nitride semiconductors, with the potential to enable high-quality and low cost GaN growth for widespread use. However, fundamental techno-logical hurdles must be overcome to enable the adoption of MSE in industrial production. Here, we present a new UHV-compatible magnetron design with high-performance cooling, enabling high GaN growth rates at high growth temperatures using a solid Ga target. The magnetron is tested with a wide range of process parameters and a stable process is feasible while maintaining the solid state of the Ga target. High GaN growth rates of up to 5 mu m/h are achieved at room temperature and a growth rate of 4 mu m/h at high temperature, which is one order of magnitude higher compared to MSE with a liquid target. We grow GaN on c-plane sapphire substrates and show the impact of partial pressure ratio and target-to-substrate distance (TSD) on growth rate, film morphology and crystal quality of GaN films with scanning electron microscopy and X-ray diffraction. While the growth rate and film morphology are strongly impacted by the process parameter variation, the crystal quality is further impacted by the overall film thickness. For a 2 mu m thick GaN film a full width at half maximum of X-ray rocking curve (omega-FWHM) of GaN 10 1 1 reflection of 0.32 degrees is achieved. We demonstrate a process window for growth of dense and smooth GaN films with high crystal quality using low N2 flow rates and high TSD. By introducing a 20 nm AlN nucleation layer prior to the growth of 390 nm GaN, the omega-FWHM of GaN 0002 reflection of 0.19 degrees is achieved. The epitaxially grown crystalline structure is precisely examined by transmission electron microscopy.

  • 6.
    Lin, Shuyao
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska fakulteten. Tech Univ Wien, Austria.
    Casillas-Trujillo, Luis
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska fakulteten.
    Tasnadi, Ferenc
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Mayrhofer, Paul H.
    Tech Univ Wien, Austria.
    Sangiovanni, Davide
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Koutna, Nikola
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten. Tech Univ Wien, Austria.
    Machine-learning potentials for nanoscale simulations of tensile deformation and fracture in ceramics2024Ingår i: npj Computational Materials, E-ISSN 2057-3960, Vol. 10, nr 1, artikel-id 67Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Machine-learning interatomic potentials (MLIPs) offer a powerful avenue for simulations beyond length and timescales of ab initio methods. Their development for investigation of mechanical properties and fracture, however, is far from trivial since extended defects-governing plasticity and crack nucleation in most materials-are too large to be included in the training set. Using TiB2 as a model ceramic material, we propose a training strategy for MLIPs suitable to simulate mechanical response of monocrystals until failure. Our MLIP accurately reproduces ab initio stresses and fracture mechanisms during room-temperature uniaxial tensile deformation of TiB2 at the atomic scale ( approximate to 103 atoms). More realistic tensile tests (low strain rate, Poisson's contraction) at the nanoscale ( approximate to 104-106 atoms) require MLIP up-fitting, i.e., learning from additional ab initio configurations. Consequently, we elucidate trends in theoretical strength, toughness, and crack initiation patterns under different loading directions. As our MLIP is specifically trained to modelling tensile deformation, we discuss its limitations for description of different loading conditions and lattice structures with various Ti/B stoichiometries. Finally, we show that our MLIP training procedure is applicable to diverse ceramic systems. This is demonstrated by developing MLIPs which are subsequently validated by simulations of uniaxial strain and fracture in TaB2, WB2, ReB2, TiN, and Ti2AlB2.

  • 7.
    Rowe, Collin
    et al.
    Rensselaer Polytech Inst, NY 12180 USA.
    Shanmugham, Sathish Kumar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Le Febvrier, Arnaud
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Ramanath, Ganpati
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Rensselaer Polytech Inst, NY 12180 USA.
    Molecularly-induced roughness and oxidation in cobalt/organodithiol/cobalt nanolayers synthesized by sputter-deposition and molecular sublimation2024Ingår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 53, nr 14, s. 6451-6458Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Integrating interfacial molecular nanolayers (MNL) with inorganic nanolayers is of interest for understanding processing-structure/chemistry correlations in hybrid nanolaminates. Here, we report the synthesis of Co/biphenyldithiol (BPDT)/Co nanolayer sandwiches by metal sputter-deposition and molecular sublimation. The density and surface roughness of the Co layers deposited on the native oxide are invariant with the Ar pressure pAr during deposition. In contrast, the Co layer roughness rCo deposited on top of the BPDT MNL increases with pAr, and correlates with a higher degree of Co oxidation. Increased roughening is attributed to MNL-accentuated self-shadowing of low mobility Co atoms at high pAr, which consequently increases Co oxidation. These results indicating MNL-induced effects on the morphology and chemistry of the inorganic layers should be of importance for tailoring nanolayered hybrid interfaces and laminates. Co/biphenyldithiol (BPDT)/Co nanolayer sandwiches are synthesized by metal sputter deposition and molecular sublimation. These results indicate molecular-nanolayer-induced effects on the morphology and chemistry, of interest for hybrid nanolaminates.

  • 8.
    Wicher, Bartosz
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Warsaw Univ Technol, Poland.
    Pshyk, Oleksandr
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Empa Swiss Fed Labs Mat Sci & Technol, Switzerland.
    Li, Xiao
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Bakhit, Babak
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Rogoz, Vladyslav
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61801 USA.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Superhard oxidation-resistant Ti1-xAlxBy thin films grown by hybrid HiPIMS/DCMS co-sputtering diboride targets without external substrate heating2024Ingår i: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 238, artikel-id 112727Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ti1-xAlxBy films (0.40 &lt;= x &lt;= 0.76, and 1.81 &lt;= y &lt;= 2.03) combining good mechanical properties and high-temperature oxidation resistance are demonstrated. Layers are grown using a hybrid high-power impulse and dc magnetron co-sputtering employing two target configurations (AlB2-HiPIMS/TiB2-DCMS and TiB2-HiPIMS/AlB2-DCMS) and no external substrate heating. Near-stoichiometric B content are achieved by co-sputtering two diboride targets. Time-resolved ion mass spectrometry analyses reveal that the ionization of the DCMS flux (Al) is much higher during TiB2-HiPIMS/AlB2-DCMS. The effect is caused by the difference in the first ionization potentials and the ionization probabilities of sputtered metals and results in lower B/metal ratios in films grown in this configuration. The B/metal ratio in the single-phase Ti1-xAlxBy decreases with increasing Al content, which is explained by the change between angular distribution of Ti and Al atoms. Alloying with Al improves the high-temperature oxidation resistance: the thickness of the oxide-scale forming after 1 h anneal at 800 degrees C decreases more than 15 times upon increasing x from 0.36 to 0.74. Ti1-xAlxBy films with 0.58 &lt;= x &lt;= 0.67 offer the best compromise between high-temperature oxidation resistance and mechanical properties with an average oxide scale thickness 90-180 nm and the hardness of 34-38 GPa.

  • 9.
    Kashiwaya, Shun
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materialdesign. Linköpings universitet, Tekniska fakulteten.
    Shi, Yuchen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Sangiovanni, Davide Giuseppe
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Magnuson, Martin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Andersson, Mike
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensor- och aktuatorsystem. Linköpings universitet, Tekniska fakulteten.
    Rosén, Johanna
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materialdesign. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Synthesis of goldene comprising single-atom layer gold2024Ingår i: Nature Synthesis, E-ISSN 2731-0582Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The synthesis of monolayer gold has so far been limited to free-standingseveral-atoms-thick layers, or monolayers confned on or inside templates.Here we report the exfoliation of single-atom-thick gold achieved throughwet-chemically etching away Ti3C2 from nanolaminated Ti3AuC2, initiallyformed by substituting Si in Ti3SiC2 with Au. Ti3SiC2 is a renown MAX phase,where M is a transition metal, A is a group A element, and X is C or N. Ourdeveloped synthetic route is by a facile, scalable and hydrofuoric acid-freemethod. The two-dimensional layers are termed goldene. Goldene layerswith roughly 9% lattice contraction compared to bulk gold are observedby electron microscopy. While ab initio molecular dynamics simulationsshow that two-dimensional goldene is inherently stable, experiments showsome curling and agglomeration, which can be mitigated by surfactants.X-ray photoelectron spectroscopy reveals an Au 4f binding energy increaseof 0.88 eV. Prospects for preparing goldene from other non-van der WaalsAu-intercalated phases, including developing etching schemes,are presented.

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  • 10.
    Ding, Haoming
    et al.
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China; CNiTECH, Peoples R China.
    Li, Youbing
    Chinese Acad Sci, Peoples R China; CNiTECH, Peoples R China.
    Li, Mian
    Chinese Acad Sci, Peoples R China; CNiTECH, Peoples R China.
    Chen, Ke
    Chinese Acad Sci, Peoples R China; CNiTECH, Peoples R China.
    Liang, Kun
    Chinese Acad Sci, Peoples R China; CNiTECH, Peoples R China.
    Chen, Guoxin
    Chinese Acad Sci, Peoples R China; CNiTECH, Peoples R China.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Persson, Per O A
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Du, Shiyu
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China; CNiTECH, Peoples R China.
    Chai, Zhifang
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China; CNiTECH, Peoples R China.
    Gogotsi, Yury
    Drexel Univ, PA 19104 USA.
    Huang, Qing
    Chinese Acad Sci, Peoples R China; CNiTECH, Peoples R China; Adv Energy Sci & Technol Guangdong Lab, Peoples R China.
    Chemical scissor-mediated structural editing of layered transition metal carbides2023Ingår i: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 379, nr 6637, s. 1130-1135Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

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  • 11.
    Etman, Ahmed
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materialdesign. Linköpings universitet, Tekniska fakulteten.
    Halim, Joseph
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materialdesign. Linköpings universitet, Tekniska fakulteten.
    Lind, Hans
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materialdesign. Linköpings universitet, Tekniska fakulteten.
    Dorri, Megan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materialdesign. Linköpings universitet, Tekniska fakulteten.
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Persson, Per O A
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Rosén, Johanna
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materialdesign. Linköpings universitet, Tekniska fakulteten.
    Computationally Driven Discovery of Quaternary Tantalum-Based MAB-Phases: Ta4M & DPRIME;SiB2 (M & DPRIME; = V, Cr, or Mo): Synthesis, Characterization, and Elastic Properties2023Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 23, nr 6, s. 4442-4447Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Out-of-plane chemically ordered transitionmetal boride(o-MAB) phases, Ta4M & DPRIME;SiB2 (M & DPRIME; = V, Cr), and a structurally equivalent disordered solidsolution MAB phase, Ta4MoSiB2, are synthesized.DFT calculations are used to examine the dynamic stability, elasticproperties, and electronic density states of the MAB phases. We report on the synthesis of computationally predictedout-of-planechemically ordered transition metal borides labeled o-MAB phases, Ta4M & DPRIME;SiB2 (M & DPRIME; =V, Cr), and a structurally equivalent disordered solid solution MABphase Ta4MoSiB2. The boride phases were preparedusing solid-state reaction sintering of the constituting elements.High-resolution scanning transmission electron microscopy along withRietveld refinement of the powder-X-ray diffraction patterns revealedthat the synthesized o-MAB phases Ta4CrSiB2 (98 wt % purity) and Ta4VSiB2 (81 wt% purity) possess chemical ordering with Ta preferentially residingin the 16l position and Cr and V in the 4c position, whereas Ta4MoSiB2 (46wt % purity) was concluded to form a disordered solid solution. Densityfunctional theory (DFT) calculations were used to investigate thedynamic stability, elastic properties, and electronic density statesfor the MAB phases, confirming the stability and suggesting the boridesbased on Cr and Mo to be stiffer than those based on V and Nb.

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  • 12.
    Furlan, Andrej
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Jansson, Ulf
    Uppsala Univ, Sweden.
    Magnuson, Martin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Correction: Crystallization characteristics and chemical bonding properties of nickel carbide thin film nanocomposites (vol 26, 415501,2014)2023Ingår i: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 35, nr 13, artikel-id 139501Artikel i tidskrift (Övrigt vetenskapligt)
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  • 13.
    Greczynski, Grzegorz
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Critical method evaluation refutes the Ar 2p signal of implanted Ar for referencing X-ray photoelectron spectra2023Ingår i: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 635, artikel-id 157598Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Correct binding energy (BE) spectra referencing of insulating samples remains the major challenge in modern XPS analyses. Ar 2p signal of implanted Ar is sometimes used for this purpose. The method relies upon the assumption that chemically inert species such as noble gas atoms would be ideally suited as other factors affecting core level peak positions (such as chemical bonding) can be excluded. Here, we present a systematic study on the Ar 2p referencing method applied to a wide range of thin film sample materials of metals, nitrides, carbides, and borides. All specimens exhibit a well-defined Fermi edge, which serves as an independent internal reference for Ar 2p spectra of in-situ implanted Ar. Ar 2p3/2 binding energy is shown to vary by as much as 5.1 eV between samples. This is more than typical chemical shifts of interest, which obviously disqualifies Ar 2p referencing. The BE of the Ar 2p peaks shows a strong correlation to the number of valence electrons available for screening, implying that the polarization energy has a major role for the observed large spread of Ar 2p3/2 BE values. In several cases of single-phase films, an additional Ar 2p doublet is observed with the Ar 2p3/2 BE referenced to the vacuum level higher than the gas phase value of 248.6 eV, which is tentatively assigned to the formation of Ar-N and Ar-C complexes stabilized by Van der Waals forces. Ar implantation into two-phase samples, exemplified here by phase-segregated NiCrC/a-C:H and nanocomposite c-TiN/SiNx thin films, leads to complex Ar 2p spectra, which further demonstrates unreliability of the referencing method. The firm conclusion of the study is that the Ar 2p3/2 peak from implanted Ar is not a remedy for the charge referencing problem.

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  • 14.
    Li, Xiao
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61801 USA.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Determining role of W+ ions in the densification of TiAlWN thin films grown by hybrid HiPIMS/DCMS technique with no external heating2023Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 41, nr 1, artikel-id 013407Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hybrid high-power impulse and dc magnetron co-sputtering (HiPIMS/DCMS) with substrate bias synchronized to the high mass metal-ion fluxes was previously proposed as a solution to reduce energy consumption during physical vapor deposition processing and enable coatings on temperature-sensitive substrates. In this approach, no substrate heating is used (substrate temperature is lower than 150 C-o) and the thermally activated adatom mobility, necessary to grow dense films, is substituted by overlapping collision cascades induced by heavy ion bombardment and consisting predominantly of low-energy recoils. Here, we present direct evidence for the crucial role of W+ ion irradiation in the densification of Ti0.31Al0.60W0.09N films grown by the hybrid W-HiPIMS/TiAl-DCMS co-sputtering. The peak target current density J(max) on the W target is varied from 0.06 to 0.78 A/cm(2) resulting in more than fivefold increase in the number of W+ ions per deposited metal atom, eta = W+/(W + Al + Ti) determined by time-resolved ion mass spectrometry analyses performed at the substrate plane under conditions identical to those during film growth. The DCMS is adjusted appropriately to maintain the W content in the films constant at Ti0.31Al0.60W0.09N. The degree of porosity, assessed qualitatively from cross-sectional SEM images and quantitatively from oxygen concentration profiles as well as nanoindentation hardness, is a strong function of eta ( J m a x ). Layers grown with low eta values are porous and soft, while those deposited under conditions of high eta are dense and hard. Nanoindentation hardness of Ti0.31Al0.60W0.09N films with the highest density is & SIM;33 GPa, which is very similar to values reported for layers deposited at much higher temperatures (420-500 C-o) by conventional metal-ion-based techniques. These results prove that the hybrid HiPIMS/DCMS co-sputtering with bias pulses synchronized to high mass metal ion irradiation can be successfully used to replace conventional solutions. The large energy losses associated with heating of the entire vacuum chamber are avoided, by focusing the energy input to where it is in fact needed, i.e., the workpiece to be coated.

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  • 15.
    Pshyk, Oleksandr V.
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Li, Xiao
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Materials Research Laboratory, University of Illinois, Urbana, IL, United States.
    Sangiovanni, Davide Giuseppe
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Discovery of Guinier-Preston zone hardening in refractory nitride ceramics2023Ingår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 255, artikel-id 119105Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Traditional age hardening mechanisms in refractory ceramics consist of precipitation of fine particles. These processes are vital for widespread wear-resistant coating applications. Here, we report novel Guinier-Preston zone hardening, previously only known to operate in soft light-metal alloys, taking place in refractory ceramics like multicomponent nitrides. The added superhardening, discovered in thin films of Ti-Al-W-N upon high temperature annealing, comes from the formation of atomic-plane-thick W disks populating {111} planes of the cubic matrix, as observed by atomically resolved high resolution scanning transmission electron microscopy and corroborated by ab initio calculations and molecular dynamics simulations. Guinier-Preston zone hardening concurrent with spinodal decomposition is projected to exist in a range of other ceramic solid solutions and thus provides a new approach for the development of advanced materials with outstanding mechanical properties and higher operational temperature range for the future demanding applications.

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  • 16.
    Dorri, Samira
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Eriksson, Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Persson, Per O A
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Bakhit, Babak
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Ghafoor, Naureen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Effects of stoichiometry and individual layer thickness ratio on the quality of epitaxial CrBx/TiBy superlattice thin films2023Ingår i: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 228, artikel-id 111842Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Studies of single crystal artificial superlattices (SLs) of transition-metal (TM) diborides, which is instru- mental to understand hardening mechanisms at nanoscale, is lacking. Here, CrBx/TiBy (0001) diboride SLs [x,y E 1.7-3.3] are grown epitaxially on Al2O3(0001) substrates by direct-current magnetron sputter epitaxy. Growth conditions for obtaining well-defined SLs with good interface quality are found at 4 mTorr Ar pressure and 600 degrees C. 1 -mu m-thick SL films deposited with modulation periods A between 1 and 10 nm, and A=6 nm SLs with TiBy-to-A layer thickness ratios F ranging from 0.2 to 0.8 are studied. SLs with A=6 nm and F in the range of 0.2-0.4, with a near stoichiometric B/TM ratio, exhibit the high- est structural quality. The effects of F and stoichiometries (B/TM ratio) on the distribution of B in the SL structures are discussed. By increasing the relative thickness of TiBy, the crystalline quality of SLs starts to deteriorate due to B segregation in over-stoichiometric TiBy, resulting in narrow epitaxial SL columnar growth with structurally-distorted B-rich boundaries. Moreover, increasing the relative thickness of under-stoichiometric CrBx enhances the SL quality and hinders formation of B-rich boundaries. The SLs are found to exhibit hardness values in the range of 29-34 GPa.(c) 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

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  • 17.
    Pshyk, Oleksandr
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61801 USA; Natl Taiwan Univ Sci & Technol, Taiwan.
    Bakhit, Babak
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Energy-efficient physical vapor deposition of dense and hard Ti-Al-W-N coatings deposited under industrial conditions2023Ingår i: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 227, artikel-id 111753Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Decreasing the growth temperature to lower energy consumption and enable deposition on temperature-sensitive substrates during thin film growth by magnetron sputtering is crucial for sustainable develop-ment. High-mass metal ion irradiation of the growing film surface with ion energy controlled by metal-ion-synchronized biasing, allows to replace conventionally-used resistive heating, as was recently demonstrated in experiments involving a hybrid high-power impulse and dc magnetron co-sputtering (HiPIMS/DCMS) setup and stationary substrates. Here, we report the extension of the method to indus-trial scale conditions. As a model-case towards understanding the role of one-fold substrate rotation on Ti0.50Al0.50N film growth employing W irradiation, we investigate the effect of two parameters: W ion energy (controlled in the range 45 &lt;= EW &lt;= 630 eV by the amplitude of synchronized substrate bias voltage) and W ion dose per deposited metal atom (determined by the target power). We show that the efficient densification of coatings grown without external heating can be achieved by minimizing the thickness of DCMS-deposited Ti0.50Al0.50N layer that is exposed to an W ion flux, or by increasing EW, at a given Ti0.50Al0.50N thickness.(c) 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

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  • 18.
    Rogoz, Vladyslav
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Sumy State Univ, Ukraine.
    Pshyk, Oleksandr
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Medicinska fakulteten. Empa Swiss Fed Labs Mat Sci & Technol, Switzerland.
    Wicher, Bartosz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Warsaw Univ Technol, Poland.
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Primetzhofer, Daniel
    Uppsala Univ, Sweden.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61801 USA.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    High-mass metal ion irradiation enables growth of high-entropy sublattice nitride thin films from elemental targets2023Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 41, nr 6, artikel-id 063108Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Synthesis of high-entropy sublattice nitride (HESN) coatings by magnetron sputtering is typically done using custom-made alloyed targets with specific elemental compositions. This approach is expensive, requires long delivery times, and offers very limited flexibility to adjust the film composition. Here, we demonstrate a new method to grow HESN films, which relies on elemental targets arranged in the multicathode configuration with substrates rotating during deposition. TiVNbMoWN films are grown at a temperature of similar to 520(degrees)C using Ti, V, Nb, and Mo targets operating in the direct current magnetron sputtering mode, while the W target, operated by high power impulse magnetron sputtering (HiPIMS), provides a source of heavy ions. The energy of the metal ions EW+ is controlled in the range from 80 to 620 eV by varying the amplitude of the substrate bias pulses V-s, synchronized with the metal-ion-rich phase of HiPIMS pulses. We demonstrate that W(+ )irradiation provides dynamic recoil mixing of the film-forming components in the near-surface atomic layers. For EW+ &gt;= 320 eV the multilayer formation phenomena, inherent for this deposition geometry, are suppressed and, hence, compositionally uniform HESN films are obtained, as confirmed by the microstructural and elemental analysis.(c) 2023 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license(http://creativecommons.org/licenses/by/4.0/)

  • 19.
    Chang, Jui-Che
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Tseng, Eric Nestor
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Lo, Yi-Ling
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Nayak, Sanjay Kumar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Lundin, Daniel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Persson, Per O. Å.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Horng, Ray-Hua
    National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hsiao, Ching-Lien
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    HiPIMS-grown AlN buffer for threading dislocation reduction in DC-magnetron sputtered GaN epifilm on sapphire substrate2023Ingår i: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 217, artikel-id 112553Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Gallium nitride (GaN) epitaxial films on sapphire (Al2O3) substrates have been grown using reactive magnetron sputter epitaxy with a liquid Ga target. Threading dislocations density (TDD) of sputtered GaN films was reduced by using an inserted high-quality aluminum nitride (AlN) buffer layer grown by reactive high power impulse magnetron sputtering (R-HiPIMS) in a gas mixture of Ar and N2. After optimizing the Ar/N2 pressure ratio and deposition power, a high-quality AlN film exhibiting a narrow full-width at half-maximum (FWHM) value of the double-crystal x-ray rocking curve (DCXRC) of the AlN(0002) peak of 0.086° was obtained by R-HiPIMS. The mechanism giving rise the observed quality improvement is attributed to the enhancement of kinetic energy of the adatoms in the deposition process when operated in a transition mode. With the inserted HiPIMS-AlN as a buffer layer for direct current magnetron sputtering (DCMS) GaN growth, the FWHM values of GaN(0002) and (10 1‾ 1) XRC decrease from 0.321° to 0.087° and from 0.596° to 0.562°, compared to the direct growth of GaN on sapphire, respectively. An order of magnitude reduction from 2.7 × 109 cm−2 to 2.0 × 108 cm−2 of screw-type TDD calculated from the FWHM of the XRC data using the inserted HiPIMS-AlN buffer layer demonstrates the improvement of crystal quality of GaN. The result of TDD reduction using the HiPIMS-AlN buffer was also verified by weak beam dark-field (WBDF) cross-sectional transmission electron microscopy (TEM).

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  • 20.
    Li, Youbing
    et al.
    Chinese Acad Sci, Peoples R China; Qianwan Inst CNiTECH, Peoples R China.
    Zhu, Shuairu
    Tianjin Univ, Peoples R China.
    Wu, Erxiao
    Chinese Acad Sci, Peoples R China; Qianwan Inst CNiTECH, Peoples R China.
    Ding, Haoming
    Chinese Acad Sci, Peoples R China; Qianwan Inst CNiTECH, Peoples R China.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Mu, Xulin
    Beijing Univ Technol, Peoples R China.
    Chen, Lu
    Chinese Acad Sci, Peoples R China; Qianwan Institute of CNiTECH, Peoples R China.
    Zhang, Yiming
    Chinese Acad Sci, Peoples R China; Qianwan Inst CNiTECH, Peoples R China.
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Chen, Ke
    Chinese Acad Sci, Peoples R China; Qianwan Inst CNiTECH, Peoples R China.
    Li, Mian
    Chinese Acad Sci, Peoples R China; Qianwan Inst CNiTECH, Peoples R China.
    Yan, Pengfei
    Beijing Univ Technol, Peoples R China.
    Persson, Per O Å
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Du, Shiyu
    Chinese Acad Sci, Peoples R China; Qianwan Inst CNiTECH, Peoples R China.
    Kuang, Yongbo
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Chai, Zhifang
    Chinese Acad Sci, Peoples R China; Qianwan Inst CNiTECH, Peoples R China.
    Huang, Qing
    Chinese Acad Sci, Peoples R China; Qianwan Inst CNiTECH, Peoples R China.
    Nanolaminated Ternary Transition Metal Carbide (MAX Phase)-Derived Core-Shell Structure Electrocatalysts for Hydrogen Evolution and Oxygen Evolution Reactions in Alkaline Electrolytes2023Ingår i: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 14, nr 2, s. 481-488Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The development of abundant, cheap, and highly active catalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is important for hydrogen production. Nanolaminate ternary transition metal carbides (MAX phases) and their derived two-dimensional transition metal carbides (MXenes) have attracted considerable interest for electrocatalyst applications. Herein, four new MAX@MXene core-shell structures (Ta2CoC@ Ta2CTx, Ta2NiC@Ta2CTx, Nb2CoC@Nb2CTx, and Nb2NiC@Nb2CTx), in which the core region is Co/Ni-MAX phases while the edge region is MXenes, have been prepared. Under alkaline electrolyte conditions, the Ta2CoC@Ta2CTx core-shell structure showed an overpotential of 239 mV and excellent stability during the HER with MXenes as the active sites. For the OER, the Ta2CoC@Ta2CTx core- shell structure showed an overpotential of 373 mV and a small Tafel plot (56 mV dec-1), which maintained a bulk crystalline structure and generated Co-based oxyhydroxides that formed by surface reconstruction as active sites. Considering rich chemical compositions and structures of MAX phases, this work provides a new strategy for designing multifunctional electrocatalysts and also paves the way for further development of MAX phase-based materials for clean energy applications.

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  • 21.
    Nzulu, Gabriel Kofi
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Högberg, Hans
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Eklund, Per
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Nude, Prosper M.
    College of Basic and Applied Sciencs, Legon-Accra, University of Ghana.
    Yaya, Abu
    School of Engineering Sciences, CBAS, Legon-Accra, University of Ghana.
    Magnuson, Martin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Pathfinder elements and indicator minerals of Au from the Kubi Gold ore deposits in Ghana2023Ingår i: Environmental Earth Sciences, ISSN 1866-6280, E-ISSN 1866-6299, Vol. 82, nr 16, artikel-id 386Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Au mineralization in the Kubi Gold Mining Area in the Birimian of Ghana is associated with garnet (about 85 vol.%), magnetite, pyrrhotite, arsenopyrite, and sulfide minerals, as well as quartz with gold and calcite. These minerals and the included elements can act as indicator minerals or pathfinder elements. For the present work, we collected samples from drill holes at different depths, from the alluvial zone (0–45 m) to the ore zone (75–100 m). The distributions of minerals and elements in the rocks that act as indicator minerals and pathfinder elements in the concession area were investigated along the drill hole cross sections. X-ray diffraction shows that the samples contain garnet, pyrite, periclase, and quartz as the main indicator minerals. By energy-dispersive X-ray spectroscopy, Fe, Mg, Al, S, O, Mn, Na, Cu, Si, and K are identified as corresponding pathfinder elements. The results indicate that the Au mineralization in the Kubi Mine area correlates mostly with the occurrence of garnet, pyrite, goethite, and kaolinite in the host rocks, which show towards the surface increasingly hematitic and limonitic alteration in form of Fe(oxy-)hydroxides.

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  • 22.
    Ghafoor, Naureen
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Dorri, Samira
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Rogström, Lina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Bakhit, Babak
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Phase separation paths in metastable Zr1-xAlxN monolithic layers compared to multilayers with TiN: Growth versus annealing temperatures2023Ingår i: Materialia, E-ISSN 2589-1529, Vol. 28, artikel-id 101758Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Metastable super-saturated Zr1_xAlxN alloys tend to phase separate into the equilibrium cubic (c) ZrN and wurtzite (w) AlN due to a deep miscibility gap. Transformation is shown here to follow distinctly different paths depending on if Zr1_xAlxN (x = 0.3 and 0.6) is sputter deposited as a single layer or multi-layered with TiN, and further varied by post-deposition annealing. Using in situ high-energy synchrotron wide-angle X-ray scattering and analytical transmission electron microscopy, surface segregation effects are compared to secondary phase transformations occurring in as-deposited layers during thermal annealing up to 1000 degrees C. For the primary phase transformation from the vapor phase, w-AlN nucleates and an AlN-ZrN labyrinthine structure evolves at elevated deposition temperature with semi-coherent interfaces over several nanometers, where the higher Al content narrows the structure in both single and multilayers. Transformation in thinner alloy layers is governed by epitaxial forces which stabilize single-phase c-Zr0.4Al0.6N, which enables c-Zr0.4Al0.6N/TiN superlattice growth at temperatures as low as 350 degrees C. Regardless of the decomposition route, the formation of c-AlN is impeded and w-AlN instantaneously forms during transformation. In contrast, isostructural decomposition into w-AlN and w-Zr (Al)N occurs in w-Zr0.4Al0.6N alloys during annealing.

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  • 23.
    Alves Machado Filho, Manoel
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Universidade Maurício de Nassau − UNINASSAU − Unidade Vitória da Conquista, 45020-750Vitória da Conquista, Bahia, Brazil.
    Hsiao, Ching-Lien
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    dos Santos, Renato Batista
    Instituto Federal de Educação, Ciência e Tecnologia Baiano, 46880-000Itaberaba, Bahia, Brazil.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Gueorguiev, Gueorgui Kostov
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Self-Induced Core–Shell InAlN Nanorods: Formation and Stability Unraveled by Ab Initio Simulations2023Ingår i: ACS Nanoscience Au, E-ISSN 2694-2496, Vol. 3, nr 1, s. 84-93Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    By addressing precursor prevalence and energetics using the DFT-based synthetic growth concept (SGC), the formation mechanism of self-induced InAlN core–shell nanorods (NRs) synthesized by reactive magnetron sputter epitaxy (MSE) is explored. The characteristics of In- and Al-containing precursor species are evaluated considering the thermal conditions at a typical NR growth temperature of around 700 °C. The cohesive and dissociation energies of In-containing precursors are consistently lower than those of their Al-containing counterparts, indicating that In-containing precursors are more weakly bonded and more prone to dissociation. Therefore, In-containing species are expected to exhibit lower abundance in the NR growth environment. At increased growth temperatures, the depletion of In-based precursors is even more pronounced. A distinctive imbalance in the incorporation of Al- and In-containing precursor species (namely, AlN/AlN+, AlN2/AlN2+, Al2N2/Al2N2+, and Al2/Al2+ vs InN/InN+, InN2/InN2+, In2N2/In2N2+, and In2/In2+) is found at the growing edge of the NR side surfaces, which correlates well with the experimentally obtained core–shell structure as well as with the distinctive In-rich core and vice versa for the Al-rich shell. The performed modeling indicates that the formation of the core–shell structure is substantially driven by the precursors’ abundance and their preferential bonding onto the growing edge of the nanoclusters/islands initiated by phase separation from the beginning of the NR growth. The cohesive energies and the band gaps of the NRs show decreasing trends with an increment in the In concentration of the NRs’ core and with an increment in the overall thickness (diameter) of the NRs. These results reveal the energy and electronic reasons behind the limited growth (up to ∼25% of In atoms of all metal atoms, i.e., InxAl1–xN, x ∼ 0.25) in the NR core and may be qualitatively perceived as a limiting factor for the thickness of the grown NRs (typically <50 nm).

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  • 24.
    Greczynski, Grzegorz
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Pshyk, Oleksandr
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Medicinska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Toward an increased reliability of chemical bonding assignment in insulating samples by x-ray photoelectron spectroscopy2023Ingår i: Science Advances, E-ISSN 2375-2548, Vol. 9, nr 37, artikel-id eadi3192Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    X-ray photoelectron spectroscopy (XPS) spectra from solid samples are conventionally referenced to the spectrometer Fermi level (FL). While, in the case of metallic samples, alignment of the sample and the spectrometer FLs can be directly verified from the measured Fermi edge position, thus allowing to assess the surface electrical potential, this is not a workable option for insulators. When applied, it generates a large spread in reported binding energy values that often exceed involved chemical shifts. By depositing insulating amorphous alumina thin films on a variety of conducting substrates with different work functions, we show not only that FL referencing fails but also that the Al2O3 energy levels align instead to the vacuum level, as postulated in the early days of XPS. Based on these model experiments that can be repeated for all sorts of thin-film insulators, a solution to the binding energy reference problem is proposed for reliable assessment of chemical bonding.

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  • 25.
    Greczynski, Grzegorz
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61801 USA.
    Towards lowering energy consumption during magnetron sputtering: Benefits of high-mass metal ion irradiation2023Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 134, nr 14, artikel-id 140901Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The quest for lowering energy consumption during thin film growth by magnetron sputtering techniques becomes of particular importance in view of sustainable development goals. As large fraction of the process energy is consumed in substrate heating for the purpose of providing high adatom mobility necessary to grow dense films, the most straightforward strategy toward more environment-friendly processing is to find alternatives to thermally activated surface diffusion. One possibility is offered by high mass metal ion irradiation of the growing film surface, which has been recently shown to be very effective in densification of transition metal nitride layers grown with no external heating, such that Zone 2 microstructures of the structure-zone model are obtained in the substrate temperature T-s range otherwise typical for Zone 1 growth. The large mass difference between the incident ion and the atoms constituting the film results in effective creation of low energy recoils, which leads to film densification at low T-s. Due to their high mass, metal ions become incorporated at lattice sites beyond the near-surface region of intense recoil generation leading to further densification, while preventing the buildup of residual stress. The practical implementation of this technique discussed in this Perspective employs heavy metal targets operating in the high-power impulse magnetron sputtering (HiPIMS) mode to provide periodic metal-ion fluxes that are accelerated in the electric field of the substrate to irradiate layers deposited from direct current magnetron sputtering (DCMS) sources. A key feature of this hybrid HiPIMS/DCMS configuration is the substrate bias that is synchronized with heavy metal ion fluxes for selective control of their energy and momentum. As a consequence, the major fraction of process energy is used at sputtering sources and for film densification, rather than for heating of the entire vacuum vessel. Model material systems include TiN and metastable NaCl-structure Ti1-yAlyN films, which are well-known for challenges in stoichiometry and phase stability control, respectively, and are of high relevance for industrial applications. This Perspective provides a comprehensive overview of the novel film growth method. After presenting basic concepts, time-resolved measurements of ion fluxes at the substrate plane, essential for selective control of metal ion energy and momentum, are discussed. The role of metal ion mass, energy, momentum, and concentration is described in more detail. As some applications require substrate rotation for conformal coating, a section is devoted to the related complexity in the implementation of metal-ion-synchronized growth under industrial conditions.

  • 26.
    Greczynski, Grzegorz
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Haasch, Richard T.
    Univ Illinois, IL USA.
    Hellgren, Niklas
    Messiah Univ, PA USA.
    Lewin, Erik
    Uppsala Univ, Sweden.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    X-ray photoelectron spectroscopy of thin films2023Ingår i: NATURE REVIEWS METHODS PRIMERS, ISSN 2662-8449, Vol. 3, nr 1, artikel-id 40Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    X-ray photoelectron spectroscopy (XPS) is a popular analytical technique in materials science as it can assess the surface chemistry of a broad range of samples. This Primer concerns best practice in XPS analysis, aimed at both entry-level and advanced users, with a focus on thin film samples synthesized under vacuum conditions. The high surface to volume ratio of thin films means that factors such as substrate choice and air exposure time are important for the final result. Essential concepts are introduced, such as binding energy, photoelectric effect, spectral referencing and chemical shift, as well as practical aspects including surface sensitivity, probing depth, energy resolution, sample handling and sputter etching. Correct procedures for experimental planning, instrument set-up, sample preparation, data acquisition, results analysis and presentation are reviewed in connection with physical principles and common applications. Typical problems, including charging, spectral overlap, sputter damage and binding energy referencing, are discussed along with possible solutions or workarounds. Finally, a workflow is presented for arriving at high-quality results. X-ray photoelectron spectroscopy (XPS) can be used to investigate chemical bonding and elemental composition. This Primer discusses how XPS can be used to characterize thin films, including key considerations for sample preparation, experimental set-up and data analysis.

  • 27.
    Greczynski, Grzegorz
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    A step-by-step guide to perform x-ray photoelectron spectroscopy2022Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 132, nr 1, artikel-id 011101Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There is a growing concern within the surface science community that the massive increase in the number of XPS articles over the last few decades is accompanied by a decrease in work quality including in many cases meaningless chemical bond assignment. Should this trend continue, it would have disastrous consequences for scientific research. While there are many factors responsible for this situation, the lack of insight of physical principles combined with seeming ease of XPS operation and insufficient training are certainly the major ones. To counter that, we offer a comprehensive tutorial written in the form of a step-by-step guide starting from experimental planning, through sample selection and handling, instrument setup, data acquisition, spectra analysis, and results presentation. Six application examples highlight the broad range of research questions that can be answered by XPS. The topic selection and the discussion level are intended to be accessible for novices yet challenging possible preconceptions of experienced practitioners. The analyses of thin film samples are chosen for model cases as this is from where the bulk of XPS reports presently emanate and also where the authors key expertise lies. At the same time, the majority of discussed topics is applicable to surface science in general and is, thus, of relevance for the analyses of any type of sample and material class. The tutorial contains ca. 160 original spectra and over 290 references for further reading. Particular attention is paid to the correct workflow, development of good research practices, and solid knowledge of factors that impact the quality and reliability of the obtained information. What matters in the end is that the conclusions from the analysis can be trusted. Our aspiration is that after reading this tutorial each practitioner will be able to perform error-free data analysis and draw meaningful insights from the rich well of XPS. Published under an exclusive license by AIP Publishing.

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  • 28.
    Koutna, Nikola
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. TU Wien, Austria.
    Löfler, Lukas
    Dept Mat Sci, Austria; Rhein Westfal TH Aachen, Germany.
    Holec, David
    Dept Mat Sci, Austria.
    Chen, Zhuo
    Erich Schmid Inst Mat Sci, Austria.
    Zhang, Zaoli
    Erich Schmid Inst Mat Sci, Austria.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Mayrhofer, Paul H.
    TU Wien, Austria.
    Sangiovanni, Davide
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Atomistic mechanisms underlying plasticity and crack growth in ceramics: a case study of AlN/TiN superlattices2022Ingår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 229, artikel-id 117809Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Interfaces between components of a material govern its mechanical strength and fracture resistance. While a great number of interfaces is present in nanolayered materials, such as superlattices, their fundamental role during mechanical loading lacks understanding. Here we combine ab initio and classical molecular dynamics simulations, nanoindentation, and transmission electron microscopy to reveal atomistic mechanisms underlying plasticity and crack growth in B1 AlN(001)/TiN(001) superlattices under loading. The system is a model for modern refractory ceramics used as protective coatings. The simulations demonstrate an anisotropic response to uniaxial tensile deformation in principal crystallographic directions due to different strain-activated plastic deformation mechanisms. Superlattices strained orthogonal to (001) interfaces show modest plasticity and cleave parallel to AlN/TiN layers. Contrarily, B1-to-B3 or B1-to-B4(B-k) phase transformations in AlN facilitate a remarkable toughness enhancement upon in plane [110] and [100] tensile elongation, respectively. We verify the predictions experimentally and conclude that strain-induced crack growth-via loss of interface coherency, dislocation-pinning at interfaces, or layer interpenetration followed by formation of slip bands-can be hindered by controlling the thicknesses of the superlattice nanolayered components.

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  • 29.
    Bangolla, Hemanth Kumar
    et al.
    Natl Taiwan Univ Sci & Technol, Taiwan.
    Siao, Ming-Deng
    Natl Taiwan Univ Sci & Technol, Taiwan.
    Huang, Yi-Hua
    Natl Taiwan Univ Sci & Technol, Taiwan.
    Chen, Ruei-San
    Natl Taiwan Univ Sci & Technol, Taiwan.
    Zukauskaite, Agne
    Fraunhofer Inst Organ Elect Electron Beam & Plasm, Germany.
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Persson, Per O Å
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hsiao, Ching-Lien
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Composition-dependent photoconductivities in indium aluminium nitride nanorods grown by magnetron sputter epitaxy2022Ingår i: Nanoscale Advances, E-ISSN 2516-0230, Vol. 4, nr 22, s. 4886-4894Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Photoconduction (PC) properties were investigated for ternary indium aluminium nitride (InxAl1-xN) nanorods (NRs) with different indium compositions (x) from 0.35 to 0.68, as grown by direct-current reactive magnetron sputter epitaxy. Cross-sectional scanning transmission electron microscopy (STEM) reveals single-crystal quality of the vertically aligned InxAl1-xN NRs. Single-rod photodetector devices with good ohmic contacts were fabricated using the focused-ion-beam technique (FIB), where the In-rich In0.68Al0.32N NR exhibits an optimal photocurrent responsivity of 1400 A W-1 and photoconductive gain of 3300. A transition from a positive photoresponse to a negative photoresponse was observed, while increasing the In composition x from 0.35 to 0.57. The negative PC was further enhanced by increasing x to 0.68. A model based on the coexistence and competition of deep electron trap states and recombination centers was proposed to explain the interesting composition-dependent PC in these ternary III-nitride 1D nanostructures.

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  • 30.
    Li, Xiao
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Bakhit, Babak
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Joesaar, M. P. Johansson
    SECO Tools AB, Sweden.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61801 USA; Natl Taiwan Univ Sci & Technol, Taiwan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Dense, single-phase, hard, and stress-free Ti0.32Al0.63W0.05N films grown by magnetron sputtering with dramatically reduced energy consumption2022Ingår i: Scientific Reports, E-ISSN 2045-2322, Vol. 12, nr 1, artikel-id 2166Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The quest for lowering energy consumption during thin film growth, as by magnetron sputtering, becomes of particular importance in view of sustainable development goals. A recently proposed solution combining high power impulse and direct current magnetron sputtering (HiPIMS/DCMS) relies on the use of heavy metal-ion irradiation, instead of conventionally employed resistive heating, to provide sufficient adatom mobility, in order to obtain high-quality dense films. The major fraction of process energy is used at the sputtering sources rather than for heating the entire vacuum vessel. The present study aims to investigate the W+ densification effects as a function of increasing Al content in (Ti1-yAly)(1-x)WxN films covering the entire range up to the practical solubility limits (y similar to 0.67). Layers with high Al content are attractive to industrial applications as the high temperature oxidation resistance increases with increasing Al concentration. The challenge is, however, to avoid precipitation of the hexagonal wurtzite AIN phase, which is softer. We report here that (T1-yAly)(1-x)WxN layers with y= 0.66 and x= 0.05 grown by a combination ofW-HiPIMS and TiAI-DCMS with the substrate bias V-s synchronized to the W+-rich fluxes (to provide mobility in the absence of substrate heating) possess single-phase NaCl-structure, as confirmed by XRD and SAED patterns. The evidence provided by XTEM images and the residual oxygen content obtained from ERDA analyses reveals that the alloy films are dense without discernable porosity. The nanoindentation hardness is comparable to that of TiAlN films grown at 400-500 degrees C, while the residual stresses are very low. We established that the adatom mobility due to the heavy ion W+ irradiation (in place of resistive heating) enables the growth of high-quality coatings at substrate temperatures not exceeding 130 degrees C provided that the W+ momentum transfer per deposited metal atom is sufficiently high. The benefit of this novel film growth approach is not only the reduction of the process energy consumption by 83%, but also the possibility to coat temperature-sensitive substrates.

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  • 31.
    Chang, Jui-Che
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Kostov Gueorguiev, Gueorgui
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Bakhit, Babak
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Eriksson, Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Sandström, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hsiao, Ching-Lien
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Domain epitaxial growth of Ta3N5 film on c-plane sapphire substrate2022Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 443, artikel-id 128581Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Tritantalum pentanitride (Ta3N5) semiconductor is a promising material for photoelectrolysis of water with high efficiency. Ta3N5 is a metastable phase in the complex system of TaN binary compounds. Growing stabilized single-crystal Ta3N5 films is correspondingly challenging. Here, we demonstrate the growth of a nearly single-crystal Ta3N5 film with epitaxial domains on c-plane sapphire substrate, Al2O3(0001), by magnetron sputter epitaxy. Introduction of a small amount ~2% of O2 into the reactive sputtering gas mixed with N2 and Ar facilitates the formation of a Ta3N5 phase in the film dominated by metallic TaN. In addition, we indicate that a single-phase polycrystalline Ta3N5 film can be obtained with the assistance of a Ta2O5 seed layer. With controlling thickness of the seed layer smaller than 10 nm and annealing at 1000 °C, a crystalline β phase Ta2O5 was formed, which promotes the domain epitaxial growth of Ta3N5 films on Al2O3(0001). The mechanism behind the stabilization of the orthorhombic Ta3N5 structure resides in its stacking with the ultrathin seed layer of orthorhombic β-Ta2O5, which is energetically beneficial and reduces the lattice mismatch with the substrate.

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  • 32.
    Schnitter, Claudia
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61801 USA; Univ Illinois, IL 61801 USA; Natl Taiwan Univ Sci & Technol, Taiwan.
    Zhirkov, Igor
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Rosén, Johanna
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Högberg, Hans
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Effect of low-energy ion assistance on the properties of sputtered ZrB2 films2022Ingår i: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 195, artikel-id 110688Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Zirconium diboride (ZrB2) films have been deposited by direct current magnetron sputtering (DCMS) from a ZrB2 compound target on Al2O3 (0001) substrates held at 600, 700, 800, and 900 degrees C, and with two different axial magnetic field strengths, 34 and 104 G, generated using a coil surrounding the substrate. Plasma probe measurements show an increase of the ion fluxes on floating-potential substrates of the two different configurations by a factor of 2.8 for 104 G compared to 34 G, while the ion energy remained relatively constant at approximate to 12 eV. Time-of-flight elastic recoil detection analysis (ToF-ERDA) show that films deposited with a magnetic field of 34 G are highly overstoichiometric with B/Zr ratios approximate to 2.4, while films deposited with 104 G exhibit a B/Zr ratios approximate to 2.1. The levels of oxygen and carbon in the films are below 1 at. % irrespective of growth conditions. X-ray diffraction (XRD) 0/20 scans, complemented by pole figure measurements, reveal that all deposited films are 0001-oriented. XRD 0/20 scans of the 000t peak intensities and co (rocking-curve) widths show increased ZrB2 crystal quality with increasing temperature for both magnetic field strengths. Minimum electrical resistivity of approximate to 100 p omega cm is achieved for an axial magnetic field of 104 G, independent of temperature.

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  • 33.
    Pshyk, A. V.
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Adam Mickiewicz Univ, Poland; Empa Swiss Fed Labs Mat Testing & Res, Switzerland.
    Vasylenko, A.
    Univ Liverpool, England.
    Bakhit, Babak
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Schweizer, P.
    Empa Swiss Fed Labs Mat Testing & Res, Switzerland.
    Edwards, T. E. J.
    Empa Swiss Fed Labs Mat Testing & Res, Switzerland.
    Michler, J.
    Empa Swiss Fed Labs Mat Testing & Res, Switzerland.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    High-entropy transition metal nitride thin films alloyed with Al: Microstructure, phase composition and mechanical properties2022Ingår i: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 219, artikel-id 110798Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Deviation from equimolar composition in high-entropy multielement ceramics offers a possibility of fine-tuning the materials properties for targeted application. Here, we present a systematic experimental and theoretical study on the effects of alloying equimolar pentanary (TiHfNbVZr)N and hexanary (TiHfNbVZrTa)N high-entropy nitrides with Al. Although being predicted to be metastable by ab initio density-functional theory calculations, single-phase fcc NaCl-structured solid solution thin films with Al solubility limits as high as x similar to 0.51-0.61 in (TiHfNbVZr)(1-x)AlxN and x similar to 0.45-0.64 in (TiHfNbVZrTa)(1-x)AlxN are synthesised utilizing a hybrid deposition technique that offers dynamic mixing of film atoms from Al+ subplantation and non-equilibrium growth conditions leading to quenching of the desired film structure. In experimental studies supplemented with density-functional theory calculations, it is demonstrated that Al concentration in alloys with the multielement compositions of high-entropy nitride thin films determine hardness, yield strength, toughness, and ability to deform plastically up to fracture due to different deformation mechanisms arising from the electronic structure and phase compositions. (C) 2022 The Author(s). Published by Elsevier Ltd.

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  • 34.
    Greczynski, Grzegorz
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Impact of sample storage type on adventitious carbon and native oxide growth: X-ray photoelectron spectroscopy study2022Ingår i: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 205, artikel-id 111463Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The type and degree of contamination on surfaces intended for X-ray photoelectron spectroscopy (XPS) studies is considered decisive for meaningful and reliable analysis as in many cases in-situ cleaning methods are not applicable or otherwise undesired. We report on the effects of sample storage environment on predominantly carbon-and oxygen-containing species accumulating on the surfaces of fourteen types of thin film samples spanning group IVB-VIB transition metals (TMs), TM nitrides, and TM diborides. All specimens were deposited by magnetron sputtering and stored for six months in different common sample storage environments such as openly on a shelf in the office or XPS lab, or within a polypropylene wafer carrier, polystyrene box, cellulose/polyester wipers or sealed polyethylene bag. Self-consistent modelling of C 1s, O 1s, B 1s, N 1s, and metal core level spectra allowed to identify the types and quantities of surface contaminants, metal oxidation states, and thicknesses of native oxides, as well as to address influence from storage ambient type and volume, direct sample contact to other surfaces, or material release from containers. The results reveal significant differences between the various storage types and, hence, provide guidance for all sorts of studies including even those that employ Ar+ ion etch prior to analyses, as also in such cases the amount and type of surface contaminants may impact the outcome.

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  • 35.
    Wu, Zhengtao
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Guangdong Univ Technol, Peoples R China.
    Ye, Rongli
    Guangdong Univ Technol, Peoples R China.
    Bakhit, Babak
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61801 USA; Natl Taiwan Univ Sci & Technol, Taiwan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Improving oxidation and wear resistance of TiB2 films by nano-multilayering with Cr2022Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 436, artikel-id 128337Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Alternating TiB2-DCMS and Cr-HiPIMS layers are used to fabricate TiB2/Cr multilayer films with varying the Cr-interlayer thickness, 2 and 5 nm, and the substrate bias during growth of Cr interlayers from floating, to -60 V and -200 V. The effects of multilayer structure on mechanical properties, static oxidation, and tribological behavior of the TiB2/Cr multilayers are investigated. The results reveal that TiB2 nanocolumns renucleate at each Cr interface maintaining smooth film surface and film density. Interlaying with Cr with thicknesses of 2-5 nm improves the resistance to oxidation at 500-600 ?& nbsp;as compared to TiB2 monolayer. The increase of the thickness of the Cr interlayers from 2 to 5 nm decreases the hardness of the multilayer slightly but deteriorates the wear rate significantly. The friction coefficients at 500 ?& nbsp;are lower than those at RT due to boric acid liquid lubrication induced by surface oxidation. The TiB2/Cr multilayer films show higher wear resistance than TiB2 monolayer. The multilayer films with 2 nm-thick Cr deposited at -60 V have the lowest recorded wear rates. Irradiation with 200 eV Cr+ leads to interface mixing, resulting in the formation of B-deficient TiBx phase (x &lt; 2) and higher wear rates compared to multilayers grown at -60 V.

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  • 36.
    Bakhit, Babak
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Dorri, Samira
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Kosari, Ali
    Delft Univ Technol, Netherlands.
    Mol, Arjan
    Delft Univ Technol, Netherlands.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61801 USA; Natl Taiwan Univ Sci & Technol, Taiwan.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Microstructure, mechanical, and corrosion properties of Zr1-xCrxBy diboride alloy thin films grown by hybrid high power impulse/DC magnetron co-sputtering2022Ingår i: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 591, artikel-id 153164Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We study microstructure, mechanical, and corrosion properties of Zr1-xCrxBy coatings deposited by hybrid high power impulse/DC magnetron co-sputtering (CrB2-HiPIMS/ZrB2-DCMS). Cr/(Zr + Cr) ratio, x, increases from 0.13 to 0.9, while B/(Zr + Cr) ratio, y, decreases from 2.92 to 1.81. As reference, ZrB2.18 and CrB1.81 layers are grown at 4000 W DCMS. ZrB2.18 and CrB1.81 columns are continual from near substrate toward the surface with open column boundaries. We find that the critical growth parameter to achieve dense films is the ratio of Cr+- dominated ion flux and the (Zr + B) neutral flux from the ZrB2 target. Thus, the alloys are categorized in two groups: films with x &lt; 0.32 (low Cr+/(Zr + B) ratios) that have continuous columnar growth, rough surfaces, and open column boundaries, and films with x &gt;= 0.32 (high Cr+/(Zr + B) ratios) that Cr+-dominated ion fluxes are sufficient to interrupt continuous columns, resulting in smooth surface and dense fine-grain microstructure. The pulsed metal-ion irradiation is more effective in film densification than continuous Ar+ bombardment. Dense Zr0.46Cr0.54B2.40 and Zr0.10Cr0.90B1.81 alloys are hard (&gt; 30 GPa) and almost stress-free with relative nano indentation toughness of 1.3 MPa root m and 2.3 MPa root m, respectively, and remarkedly low corrosion rates (~& nbsp;1.0 x 10(-6) mA/cm(2) for Zr0.46Cr0.54B2.40 and~& nbsp; 2.1 x 10(-6) mA/cm(2) for Zr0.10Cr0.90B1.81).

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  • 37.
    Petrov, Ivan
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61820 USA.
    Desjardins, Patrick
    Polytech Montreal, Canada.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Obituary: Obituary Professor Joe Greene2022Ingår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 763, artikel-id 139599Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 38.
    Palisaitis, Justinas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Dahlqvist, Martin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materialdesign. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61801 USA; Natl Taiwan Univ Sci & Technol, Taiwan.
    Rosén, Johanna
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materialdesign. Linköpings universitet, Tekniska fakulteten.
    Persson, Per O A
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    On the nature of planar defects in transition metal diboride line compounds2022Ingår i: Materialia, E-ISSN 2589-1529, Vol. 24, artikel-id 101478Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Planar defect structures appearing in transition metal diboride (TMB2) thin films, grown by different magnetron sputtering-deposition approaches over a wide compositional and elemental range, were systematically investi-gated. Atomically resolved scanning transmission electron microscopy (STEM) imaging, electron energy loss spec-troscopy (EELS) elemental mapping, and first principles calculations have been applied to elucidate the atomic structures of the observed defects. Two distinct types of antiphase boundary (APB) defects reside on the {1(1) over bar 00} planes. These defects are without (named APB-1) or with (APB-2) local deviation from stoichiometry. APB-2 de-fects, in turn, appear in different variants. It is found that APB-2 defects are governed by the films composition, while APB-1 defects are endemic. The characteristic structures, interconnections, and circumstances leading to the formation of these APB-defects, together with their formation energies, are presented.

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  • 39.
    Dorri, Samira
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. University of Illinois at Urbana-Champaign, USA; National Taiwan University of Science and Technology, Taiwan.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Bakhit, Babak
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Oxidation kinetics of overstoichiometric TiB2 thin films grown by DC magnetron sputtering2022Ingår i: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 206, artikel-id 110493Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We systematically study the oxidation properties of sputter-deposited TiB2.5 coatings up to 700 °C. Oxide-scale thickness dox increases linearly with time ta for 300, 400, 500, and 700 °C, while an oxidation-protective behavior occurs with dox=250∙ta0.2 at 600 °C. Oxide-layer’s structure changes from amorphous to rutile/anatase-TiO2 at temperatures ≥ 500 °C. Abnormally low oxidation rate at 600 °C is attributed to a highly dense columnar TiO2-sublayer growing near oxide/film interface with a top-amorphous thin layer, suppressing oxygen diffusion. A model is proposed to explain the oxide-scale evolution at 600 °C. Decreasing heating rate to 1.0 °C/min plays a noticeable role in the TiB2.5 oxidation.

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  • 40.
    Thörnberg, Jimmy
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materialdesign. Linköpings universitet, Tekniska fakulteten.
    Mraz, Stanislav
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Klimashin, Fedor
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materialdesign. Linköpings universitet, Tekniska fakulteten.
    Ondracka, Pavel
    Rhein Westfal TH Aachen, Germany.
    Bakhit, Babak
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Polcik, Peter
    Plansee Composite Mat GmbH, Germany.
    Kolozsvari, Szilard
    Plansee Composite Mat GmbH, Germany.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61801 USA; Natl Taiwan Univ Sci & Technol, Taiwan.
    Persson, Per O A
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Schneider, Jochen M.
    Rhein Westfal TH Aachen, Germany.
    Rosén, Johanna
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materialdesign. Linköpings universitet, Tekniska fakulteten.
    Oxidation resistance and mechanical properties of sputter-deposited Ti0.9Al0.1B2-y thin films2022Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 442, artikel-id 128187Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Direct-current magnetron sputtering (DCMS) and high-power impulse magnetron sputtering (HiPIMS) were used to deposit understoichiometric Ti(1-x)Al(x)B(2-y )diboride coatings by sputtering from a segmented TiB2-AlB2 target using Ar and Kr as sputtering gas. For films with a fixed Al/(Ti + Al) ratio of x = 0.1 (Ti0.9Al0.1B2-y), the B content was varied with y & ISIN; (0.1, 0.6 and 0.7). For films with a fixed y = 0.7 (Ti1-xAlxB1.3), the Al content was varied with x & ISIN; (0.1, 0.4 and 0.7). Evaluation of the mechanical properties of the Ti1-xAlxB1.3 samples showed a reduction in both hardness and elastic modulus with increasing Al concentration, while the Ti0.9Al0.1B2-y samples showed a hardness increase with decreasing B content. Thus, Ti0.9Al0.1B1.3 films exhibited a superior hardness of 46.2 +/- 1.1 GPa and an elastic modulus of 523 & PLUSMN; 7 GPa, compared to the values for Ti0.9Al0.1B1.4 and Ti0.9Al0.1B1.9, showing a hardness of 44 +/- 1 GPa and 36 +/- 1 GPa, and an elastic modulus of 569 +/- 7 GPa and 493 +/- 6 GPa, respectively. The oxidation behavior of the mechanically most promising Ti0.9Al0.1B2-y sample series was investigated through air-annealing at 600 C for durations from 1 h to 10 h. All films formed a mixed non-conformal Al2O3-TiO2 oxide scale which acts as an inward and outward diffusion barrier, significantly reducing the oxidation rate compared to TiBz films, which form an oxide scale consisting of porous TiO2. The thinnest oxide scale after 10 h was found in the B-deficient samples, Ti0.9Al0.1B1.3 and Ti0.9Al0.1B1.4, at ~200 nm, which is significantly below that for Ti0.9Al0.1B1.9 at 320 nm. The enhanced oxidation resistance of highly understoichiometric films is due to the elimination of the B-rich tissue phase that is present at the grain boundaries for higher B content, where the latter has been shown to enhance the rate of oxidation in borides.

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  • 41.
    Malyshev, O. B.
    et al.
    STFC Daresbury Laboratory, Warrington, UK.
    Mayrhofer, P. H.
    TU Wien University, Vienna, Austria.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Sabbatini, L.
    University of Bari Department of Chemistry, Bari, Italy.
    Preface2022Ingår i: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 197, artikel-id 110818Artikel i tidskrift (Övrigt vetenskapligt)
  • 42.
    Greczynski, Grzegorz
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Referencing to adventitious carbon in X-ray photoelectron spectroscopy: Can differential charging explain C 1s peak shifts?2022Ingår i: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 606, artikel-id 154855Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    C 1s peak of adventitious carbon (AdC), often used for charge referencing XPS spectra, shows markedly large shifts from the "recommended" value of 284.8 eV that basically disqualifies its reliability. In some earlier papers we attributed this spreading effect to the vacuum level (VL) alignment at the AdC/sample interface, which makes the measured position of C 1s peak highly sensitive to the sample work function . Recently, it was suggested [M.C. Biesinger, Appl. Surf. Sci. 597 (2022) 153681] that it is instead the differential charging in the native oxide layers that sometimes accounts for C 1s shifts and that electrically isolating samples from the spectrometer would solve the problem. To evaluate this hypothesis, we performed a series of experiments with Au and Al foils electrically isolated from the spectrometer, while varying the surface potential in a relatively wide range by adjusting the charge neutralizer settings. Markedly, the C 1s peak positions recorded from Au and Al foils are distinctly different when referred to their Fermi levels, at respectively 284.80 +/- 0.05 eV and 286.31 +/- 0.06 eV, independent of the surface potential. This confirms the interpretation presented in our previous papers (experiments performed in a conventional way with samples connected to spectrometer), that the binding energy of C 1s peaks from Au and Al foils differs significantly due to the corresponding difference in their work function values, such that the sum is constant at similar to 289.6 eV, as imposed by the VL alignment. In addition, the energy separation between metal and oxide peaks in Al 2p spectra from Al foil is independent of the surface potential (controlled by the charge neutralizer settings), the photoelectron current (varied by adjusting x-ray power) and the Al oxide thickness (in the range from 0.7 to 4.7 nm). These observations disprove differential charging as the general cause of C 1s peak shifts at least for the case of Al foils with thinner oxide layers. As many thicker oxides are well-known to develop charging, a similar type of analysis can be performed on the case-tocase bases to determine the reasons for C 1s peak shifts.

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  • 43.
    Wu, Zhengtao
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Guangdong Univ Technol, Peoples R China.
    Ye, Rongli
    Guangdong Univ Technol, Peoples R China.
    Bakhit, Babak
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61801 USA; Natl Taiwan Univ Sci & Technol, Taiwan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Reprint of: Improving oxidation and wear resistance of TiB2 films by nano-multilayering with Cr*2022Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 442, artikel-id 128602Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Alternating TiB2-DCMS and Cr-HiPIMS layers are used to fabricate TiB2/Cr multilayer films with varying the Cr interlayer thickness, 2 and 5 nm, and the substrate bias during growth of Cr interlayers from floating, to -60 V and -200 V. The effects of multilayer structure on mechanical properties, static oxidation, and tribological behavior of the TiB2/Cr multilayers are investigated. The results reveal that TiB2 nanocolumns renucleate at each Cr interface maintaining smooth film surface and film density. Interlaying with Cr with thicknesses of 2-5 nm improves the resistance to oxidation at 500-600 degrees C as compared to TiB2 monolayer. The increase of the thickness of the Cr interlayers from 2 to 5 nm decreases the hardness of the multilayer slightly but deteriorates the wear rate significantly. The friction coefficients at 500 degrees C are lower than those at RT due to boric acid liquid lubrication induced by surface oxidation. The TiB2/Cr multilayer films show higher wear resistance than TiB2 monolayer. The multilayer films with 2 nm-thick Cr deposited at -60 V have the lowest recorded wear rates. Irradiation with 200 eV Cr+ leads to interface mixing, resulting in the formation of B-deficient TiBx phase (x &lt; 2) and higher wear rates compared to multilayers grown at -60 V.

  • 44.
    Magnuson, Martin
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Högberg, Hans
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Review of Transition-Metal Diboride Thin Films2022Ingår i: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 196, artikel-id 110567Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    We review the thin film growth, chemistry, and physical properties of Group 4-6 transition-metal diboride (TMB2) thin films with AlB2-type crystal structure (Strukturbericht designation C32). Industrial applications are growing rapidly as TMB2 begin competing with conventional refractory ceramics like carbides and nitrides, including pseudo-binaries such as Ti1-xAlxN. The TMB2 crystal structure comprises graphite-like honeycombed atomic sheets of B interleaved by hexagonal close-packed TM layers. From the C32 crystal structure stems unique properties including high melting point, hardness, and corrosion resistance, yet limited oxidation resistance, combined with high electrical conductivity. We correlate the underlying chemical bonding, orbital overlap, and electronic structure to the mechanical properties, resistivity, and high-temperature properties unique to this class of materials. The review highlights the importance of avoiding contamination elements (like oxygen) and boron segregation on both the target and substrate sides during sputter deposition, for better-defined properties, regardless of the boride system investigated. This is a consequence of the strong tendency for B to segregate to TMB2 grain boundaries for boron-rich compositions of the growth flux. It is judged that sputter deposition of TMB2 films is at a tipping point towards a multitude of applications for TMB2 not solely as bulk materials, but also as protective coatings and electrically conducting high-temperature stable thin films.

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  • 45.
    Hellgren, Niklas
    et al.
    Messiah Univ, PA 17055 USA.
    Sredenschek, Alexander
    Messiah Univ, PA 17055 USA; Penn State Univ, PA 16801 USA.
    Petruhins, Andrejs
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materialdesign. Linköpings universitet, Tekniska fakulteten.
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Klimashin, Fedor
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materialdesign. Linköpings universitet, Tekniska fakulteten. EMPA, Switzerland.
    Sortica, Maurico A.
    Uppsala Univ, Sweden.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Persson, Per O Å
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Rosén, Johanna
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materialdesign. Linköpings universitet, Tekniska fakulteten.
    Synthesis and characterization of TiBx (1.2 ≤ x ≤ 2.8) thin films grown by DC magnetron co-sputtering from TiB2 and Ti targets2022Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 433, artikel-id 128110Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Titanium boride, TiBx, thin films were grown by direct current magnetron co-sputtering from a compound TiB2 target and a Ti target at an Ar pressure of 2.2 mTorr (0.3 Pa) and substrate temperature of 450 ?degrees C. While keeping the power of the TiB2 target constant at 250 W, and by varying the power on the Ti target, P-Ti, between 0 and 100 W, the B/Ti ratio in the film could be continuously and controllably varied from 1.2 to 2.8, with close-tostoichiometric diboride films achieved for P-Ti = 50 W. This was done without altering the deposition pressure, which is otherwise the main modulator for the composition of magnetron sputtered TiBx diboride thin films. The film structure and properties of the as-deposited films were compared to those after vacuum-annealing for 2 h at 1100 ?degrees C. As-deposited films consisted of small (?50 nm) randomly oriented TiB2 crystallites, interspersed in an amorphous, sometimes porous tissue phase. Upon annealing, some of the tissue phase crystallized, but the diboride average grain size did not change noticeably. The near-stoichiometric film had the lowest resistivity, 122 mu omega cm, after annealing. Although this film had growth-induced porosity, an interconnected network of elongated crystallites provides a path for conduction. All films exhibited high hardness, in the 25-30 GPa range, where the highest value of similar to 32 GPa was obtained for the most Ti-rich film after annealing. This film had the highest density and was nano-crystalline, where dislocation propagation is interrupted by the off-stoichiometric grain boundaries.

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  • 46.
    Bakhit, Babak
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Wu, Zhengtao
    School of Electromechanical Engineering, Guangdong University of Technology, China.
    Sortica, Mauritio A.
    Applied Nuclear Physics, Department of Physics and Astronomy, Uppsala University, Sweden.
    Primetzhofer, Daniel
    Applied Nuclear Physics, Department of Physics and Astronomy, Uppsala University, Sweden.
    Persson, Per O. Å.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Rosén, Johanna
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Materials Research Laboratory and Department of Materials Science, University of Illinois, USA; Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taiwan.
    Greene, Joseph E.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Materials Research Laboratory and Department of Materials Science, University of Illinois, USA; Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taiwan.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Age hardening in superhard ZrB2-rich Zr1-xTaxBy thin films2021Ingår i: Scripta Materialia, ISSN 1359-6462, E-ISSN 1872-8456, Vol. 191, s. 120-125Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We recently showed that sputter-deposited Zr1-xTaxBy thin films have hexagonal AlB2-type columnar nanostructure in which column boundaries are B-rich for x < 0.2, while Ta-rich for x ≥ 0.2. As-deposited layers with x ≥ 0.2 exhibit higher hardness and, simultaneously, enhanced toughness. Here, we study the mechanical properties of ZrB2.4, Zr0.8Ta0.2B1.8, and Zr0.7Ta0.3B1.5 films annealed in Ar atmosphere as a function of annealing temperature Ta up to 1200 °C. In-situ and ex-situ nanoindentation analyses reveal that all films undergo age hardening up to Ta = 800 °C, with the highest hardness achieved for Zr0.8Ta0.2B1.8 (45.5±1.0 GPa). The age hardening, which occurs without any phase separation or decomposition, can be explained by point-defect recovery that enhances chemical bond density. Although hardness decreases at Ta > 800 °C due mainly to recrystallization, column coarsening, and planar defect annihilation, all layers show hardness values above 34 GPa over the entire Ta range.

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  • 47.
    Zhou, Jie
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Halim, Joseph
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Dahlqvist, Martin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Tao, Quanzheng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Persson, Ingemar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Persson, Per O A
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Rosén, Johanna
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Boridene: Two-dimensional Mo4/3B2-x with ordered metal vacancies obtained by chemical exfoliation2021Ingår i: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 373, nr 6556, s. 801-+Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Extensive research has been invested in two-dimensional (2D) materials, typically synthesized by exfoliation of van der Waals solids. One exception is MXenes, derived from the etching of constituent layers in transition metal carbides and nitrides. We report the experimental realization of boridene in the form of single-layer 2D molybdenum boride sheets with ordered metal vacancies, Mo4/3B2-xTz (where T-z is fluorine, oxygen, or hydroxide surface terminations), produced by selective etching of aluminum and yttrium or scandium atoms from 3D in-plane chemically ordered (Mo2/3Y1/3)(2)AlB2 and (Mo2/3Sc1/3)(2)AlB2 in aqueous hydrofluoric acid. The discovery of a 2D transition metal boride suggests a wealth of future 2D materials that can be obtained through the chemical exfoliation of laminated compounds.

  • 48.
    Bakhit, Babak
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Mráz, Stanislav
    Materials Chemistry, RWTH Aachen University, Aachen, Germany.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Rosén, Johanna
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Schneider, Jochen M.
    Materials Chemistry, RWTH Aachen University, Aachen, Germany.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Materials Research Laboratory and Department of Materials Science, University of Illinois, Urbana, IL, USA; Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Dense Ti0.67Hf0.33B1.7 thin films grown by hybrid HfB2-HiPIMS/TiB2-DCMS co-sputtering without external heating2021Ingår i: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 186, artikel-id 110057Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There is a need for developing synthesis techniques that allow the growth of high-quality functional films at low substrate temperatures to minimize energy consumption and enable coating temperature-sensitive substrates. A typical shortcoming of conventional low-temperature growth strategies is insufficient atomic mobility, which leads to porous microstructures with impurity incorporation due to atmosphere exposure, and, in turn, poor mechanical properties. Here, we report the synthesis of dense Ti0.67Hf0.33B1.7 thin films with a hardness of ∼41.0 GPa grown without external heating (substrate temperature below ∼100 °C) by hybrid high-power impulse and dc magnetron co-sputtering (HfB2-HiPIMS/TiB2-DCMS) in pure Ar on Al2O3(0001) substrates. A substrate bias potential of −300 V is synchronized to the target-ion-rich portion of each HiPIMS pulse. The limited atomic mobility inherent to such desired low-temperature deposition is compensated for by heavy-mass ion (Hf+) irradiation promoting the growth of dense Ti0.67Hf0.33B1.7.

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  • 49.
    Li, Youbing
    et al.
    Chinese Acad Sci, Peoples R China; Qianwan Inst CNiTECH, Peoples R China.
    Ma, Guoliang
    Sichuan Univ, Peoples R China.
    Shao, Hui
    Univ Toulouse III Paul Sabatier, France.
    Xiao, Peng
    Sichuan Univ, Peoples R China.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Xu, Jin
    Dongguan Univ Technol, Peoples R China.
    Hou, Jinrong
    Tongji Univ, Peoples R China.
    Chen, Ke
    Chinese Acad Sci, Peoples R China; Qianwan Inst CNiTECH, Peoples R China.
    Zhang, Xiao
    Chinese Acad Sci, Peoples R China; Qianwan Inst CNiTECH, Peoples R China.
    Li, Mian
    Chinese Acad Sci, Peoples R China; Qianwan Inst CNiTECH, Peoples R China.
    Persson, Per O A
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Du, Shiyu
    Chinese Acad Sci, Peoples R China; Qianwan Inst CNiTECH, Peoples R China.
    Chai, Zhifang
    Chinese Acad Sci, Peoples R China; Qianwan Inst CNiTECH, Peoples R China.
    Huang, Zhengren
    Chinese Acad Sci, Peoples R China; Qianwan Inst CNiTECH, Peoples R China.
    Jin, Na
    Sichuan Univ, Peoples R China.
    Ma, Jiwei
    Tongji Univ, Peoples R China.
    Liu, Ying
    Sichuan Univ, Peoples R China.
    Lin, Zifeng
    Sichuan Univ, Peoples R China.
    Huang, Qing
    Chinese Acad Sci, Peoples R China; Qianwan Inst CNiTECH, Peoples R China.
    Electrochemical Lithium Storage Performance of Molten Salt Derived V2SnC MAX Phase2021Ingår i: Nano-Micro Letters, ISSN 2311-6706, Vol. 13, nr 1, artikel-id 158Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    MAX phases are gaining attention as precursors of two-dimensional MXenes that are intensively pursued in applications for electrochemical energy storage. Here, we report the preparation of V2SnC MAX phase by the molten salt method. V2SnC is investigated as a lithium storage anode, showing a high gravimetric capacity of 490 mAh g(-1) and volumetric capacity of 570 mAh cm(-3) as well as superior rate performance of 95 mAh g(-1) (110 mAh cm(-3)) at 50 C, surpassing the ever-reported performance of MAX phase anodes. Supported by operando X-ray diffraction and density functional theory, a charge storage mechanism with dual redox reaction is proposed with a Sn-Li (de)alloying reaction that occurs at the edge sites of V2SnC particles where Sn atoms are exposed to the electrolyte followed by a redox reaction that occurs at V2C layers with Li. This study offers promise of using MAX phases with M-site and A-site elements that are redox active as high-rate lithium storage materials.

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  • 50.
    Weigel, Kai
    et al.
    Fraunhofer Inst Surface Engn & Thin Films IST, Germany.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Bewilogua, Klaus
    Fraunhofer Inst Surface Engn & Thin Films IST, Germany.
    Keunecke, Martin
    Fraunhofer Inst Surface Engn & Thin Films IST, Germany.
    Petersen, Jan
    Fraunhofer Inst Surface Engn & Thin Films IST, Germany.
    Grumbt, Gundis
    IMA Mat & Anwendungstech GmbH, Germany.
    Zenker, Rolf
    Tech Univ Bergakad Freiberg, Germany; Zenker Consult, Germany.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Electron irradiation induced modifications of Ti(1-x)AlxN coatings and related buffer layers on steel substrates2021Ingår i: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 185, artikel-id 110028Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ti(1-x )AlxN hard coatings were prepared by reactive magnetron sputtering onto steel substrates (51CrV4 - 1.8159) and subsequently exposed for a short-time (similar to 1 s) to high-flux electron beam (EB) treatment. Morphology, composition and the structure of as-deposited and EB treated coatings were investigated using transmission electron microscopy (TEM), secondary ion mass spectroscopy (SIMS) and X-ray diffraction (XRD). It was found that the EB treatment had only a minor influence on the morphology and crystallinity of the Ti(1-x)AlxN phase, however, the stress-free lattice parameter and partly the compressive stress in the coatings were clearly reduced by the treatment. On the other hand, major changes of composition profiles and structure were observed in the metallic buffer layer between substrate and Ti(1-x)AlxN. The observed modifications in the coating-substrate system are explained by rapid heat up and radiation damage due to the fast electron exposure.

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