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  • 1.
    Alami, J.
    et al.
    Sulzer Metaplas GmbH, Germany.
    Sarakinos, Kostas
    Institute of Physics (IA), RWTH Aachen University, Germany.
    Uslu, F.
    RWTH Aachen University, Germany.
    Klever, C.
    RWTH Aachen University, Germany.
    Dukwen, J.
    RWTH Aachen University, Germany.
    Wuttig, M.
    RWTH Aachen University, Germany.
    On the phase formation of titanium oxide films grown by reactive high power pulsed magnetron sputtering2009Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 42, nr 11, s. 115204-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High power pulsed magnetron sputtering is used for the growth of titanium dioxide (TiO(2)) films at different working pressures and orientations of the substrate with respect to the target surface. In the case of substrates oriented parallel to the target surface, the increase in the working pressure from 0.5 to 3 Pa results in the growth of crystalline TiO(2) films with phase compositions ranging from rutile to anatase/rutile mixtures. When depositions are performed on substrates placed perpendicularly to the target surface, rutile films that consist of TiO(2) nanocrystals embedded in an amorphous matrix are obtained at 0.5 Pa. Increase in the working pressure leads to the deposition of amorphous films. These findings are discussed in the light of the energetic bombardment provided to the growing film at the various deposition conditions.

  • 2.
    Alami, J.
    et al.
    University of Aachen, Germany.
    Sarakinos, Kostas
    Institute of Physics (IA), RWTH Aachen University, Germany.
    Uslu, F.
    University of Aachen, Germany.
    Wuttig, M.
    University of Aachen, Germany.
    On the relationship between the peak target current and the morphology of chromium nitride thin films deposited by reactive high power pulsed magnetron sputtering2009Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 42, nr 1, s. 015304-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High power pulsed magnetron sputtering (HPPMS) is used to deposit CrN films without external heating at different peak target currents, while the average current is kept constant. Films are also grown by dc magnetron sputtering (dcMS), for reference. The plasma properties, the deposition rate and the morphology of the films are investigated. The plasma analysis reveals that HPPMS provides higher fluxes of ionized species (both gas and sputtered) to the growing film, as compared with dcMS. In addition, the ionic bombardment during HPPMS increases, when the peak target current is increased. The HPPMS films exhibit changes of the density and the surface roughness as the peak target current increased, while the deposition rate decreases drastically. Furthermore, it is found that different thin-film morphologies are obtained starting from a porous columnar morphology for the dcMS films, which turns to a dense columnar one at low peak target currents and ends up to a featureless morphology at high peak target currents for the films grown by HPPMS. A new structure zone model specific for high ionization sputtering is, therefore, outlined.

  • 3.
    Ben Sedrine, Nabiha
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan. University of Aveiro, Portugal; University of Aveiro, Portugal.
    Zukauskaite, Agne
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska fakulteten. Fraunhofer Institute Appl Solid State Phys, Germany.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Jensen, 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.
    Schoeche, S.
    University of Nebraska, NE 68588 USA.
    Schubert, M.
    University of Nebraska, NE 68588 USA.
    Darakchieva, Vanya
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Infrared dielectric functions and optical phonons of wurtzite YxAl1-xN (0 less than= x less than= 0.22)2015Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 48, nr 41, s. 415102-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    YAlN is a new member of the group-III nitride family with potential for applications in next generation piezoelectric and light emitting devices. We report the infrared dielectric functions and optical phonons of wurtzite (0001) YxAl1-xN epitaxial films with 0 less than= x less than= 0.22. The films are grown by magnetron sputtering epitaxy on c-plane Al2O3 and their phonon properties are investigated using infrared spectroscopic ellipsometry and Raman scattering spectroscopy. The infrared-active E-1(TO) and LO, and the Raman active E-2 phonons are found to exhibit one-mode behavior, which is discussed in the framework of the MREI model. The compositional dependencies of the E-1(TO), E-2 and LO phonon frequencies, the high-frequency limit of the dielectric constant, epsilon(infinity), the static dielectric constant, epsilon(0), and the Born effective charge Z(B) are established and discussed.

    Fulltekst (pdf)
    fulltext
  • 4.
    Beyer, Franziska
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hemmingsson, Carl
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Isoya, J
    University of Tsukuba, Japan .
    Morishita, N
    Japan Atom Energy Agency, Japan .
    Ohshima, T
    University of Tsukuba, Japan .
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Capacitance transient study of a bistable deep level in e(-)-irradiated n-type 4H-SiC2012Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 45, nr 45Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Using capacitance transient techniques, a bistable centre, called FB centre here, was observed in electron irradiated 4H-SiC. In configuration A, the deep level known as EH5 (E-a = E-C - 1.07 eV) is detected in the deep level transient spectroscopy spectrum, whereas for configuration B no obvious deep level is observed in the accessible part of the band gap. Isochronal annealing revealed the transition temperatures to be T-A -andgt; B andgt; 730K and for the opposite process T-B -andgt; A approximate to 710 K. The energy needed to conduct the transformations were determined to be E-A(A -andgt; B) = (2.1 +/- 0.1) eV and E-A(B -andgt; A) = (2.3 +/- 0.1) eV, respectively. The pre-factor indicated an atomic jump process for the opposite transition A -andgt; B and a charge carrier-emission dominated process in the case of B -andgt; A. Minority charge carrier injection enhanced the transformation from configuration B to configuration A by lowering the transition barrier by about 1.4 eV. Since the bistable FB centre is already present after low-energy electron irradiation (200 keV), it is likely related to carbon.

    Fulltekst (pdf)
    fulltext
  • 5.
    Cemin, Felipe
    et al.
    Univ Paris Saclay, France.
    Tsukamoto, Makoto
    Tokyo Metropolitan Univ, Japan.
    Keraudy, Julien
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Antunes, Vinicius Gabriel
    Univ Estadual Campinas, Brazil.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Alvarez, Fernando
    Univ Estadual Campinas, Brazil.
    Minea, Tiberiu
    Univ Paris Saclay, France.
    Lundin, Daniel
    Univ Paris Saclay, France.
    Low-energy ion irradiation in HiPIMS to enable anataseTiO(2) selective growth2018Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 51, nr 23, artikkel-id 2353011Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High power impulse magnetron sputtering (HiPIMS) has already demonstrated great potential for synthesizing the high-energy crystalline phase of titanium dioxide (rutile Ti-O2) due to large quantities of highly energetic ions present in the discharge. In this work, it is shown that the metastable anatase phase can also be obtained by HiPIMS. The required deposition conditions have been identified by systematically studying the phase formation, microstructure and chemical composition as a function of mode of target operation as well as of substrate temperature, working pressure, and peak current density. It is found that films deposited in the metal and transition modes are predominantly amorphous and contain substoichiometric TiOx compounds, while in compound mode they are well-crystallized and present only O2- ions bound to Ti4+, i.e. pure TiO2. Anatase TiO2 films are obtained for working pressures between 1 and 2 Pa, a peak current density of similar to 1 A cm(-2) and deposition temperatures lower than 300 degrees C. Rutile is favored at lower pressures (amp;lt; 1 Pa) and higher peak current densities (amp;gt;2 A cm(-2)), while amorphous films are obtained at higher pressures (greater than or similar to 5 Pa). Microstructural characterization of selected films is also presented.

  • 6.
    Delavari, Najmeh
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Tybrandt, Klas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Piro, Benoit
    Univ Paris, France.
    Noel, Vincent
    Univ Paris, France.
    Mattana, Giorgio
    Univ Paris, France.
    Zozoulenko, Igor
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Nernst-Planck-Poisson analysis of electrolyte-gated organic field-effect transistors2021Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 54, nr 41, artikkel-id 415101Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electrolyte-gated organic field-effect transistors (EGOFETs) represent a class of organic thin-film transistors suited for sensing and biosensing in aqueous media, often at physiological conditions. The EGOFET device includes electrodes and an organic semiconductor channel in direct contact with an electrolyte. Upon operation, electric double layers are formed along the gate-electrolyte and the channel-electrolyte interfaces, but ions do not penetrate the channel. This mode of operation allows the EGOFET devices to run at low voltages and at a speed corresponding to the rate of forming electric double layers. Currently, there is a lack of a detailed quantitative model of the EGOFETs that can predict device performance based on geometry and material parameters. In the present paper, for the first time, an EGOFET model is proposed utilizing the Nernst-Planck-Poisson equations to describe, on equal footing, both the polymer and the electrolyte regions of the device configuration. The generated calculations exhibit semi-qualitative agreement with experimentally measured output and transfer curves.

    Fulltekst (pdf)
    fulltext
  • 7.
    dos Santos, R. B.
    et al.
    University of Federal Bahia, Brazil.
    Rivelino, R.
    University of Federal Bahia, Brazil.
    de Brito Mota, F.
    University of Federal Bahia, Brazil.
    Kostov Gueorguiev, Gueorgui
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Kakanakova-Gueorguie, Anelia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Dopant species with Al-Si and N-Si bonding in the MOCVD of AlN implementing trimethylaluminum, ammonia and silane2015Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 48, nr 29, artikkel-id 295104Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have investigated gas-phase reactions driven by silane (SiH4), which is the dopant precursor in the metalorganic chemical vapor deposition (MOCVD) of aluminum nitride (AlN) doped by silicon, with prime focus on determination of the associated energy barriers. Our theoretical strategy is based on combining density-functional methods with minimum energy path calculations. The outcome of these calculations is suggestive for kinetically plausible and chemically stable reaction species with Al-Si bonding such as (CH3)(2)AlSiH3 and N-Si bonding such as H2NSiH3. Within this theoretical perspective, we propose a view of these reaction species as relevant for the actual MOCVD of Si-doped AlN, which is otherwise known to be contributed by the reaction species (CH3)(2)AlNH2 with Al-N bonding. By reflecting on experimental evidence in the MOCVD of various doped semiconductor materials, it is anticipated that the availability of dopant species with Al-Si, and alternatively N-Si bonding near the hot deposition surface, can govern the incorporation of Si atoms, as well as other point defects, at the AlN surface.

  • 8.
    Eklund, Per
    et al.
    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.
    Persson, Per O A
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Layered ternary M(n+1)AX(n) phases and their 2D derivative MXene: an overview from a thin-film perspective2017Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 50, nr 11, artikkel-id 113001Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Inherently and artificially layered materials are commonly investigated both for fundamental scientific purposes and for technological application. When a layered material is thinned or delaminated to its physical limits, a two-dimensional (2D) material is formed and exhibits novel properties compared to its bulk parent phase. The complex layered phases known as MAX phases (where M = early transition metal, A = A-group element, e.g. Al or Si, and X = C or N) are an exciting model system for materials design and the understanding of process-structure-property relationships. When the A layers are selectively etched from the MAX phases, a new type of 2D material is formed, named MXene to emphasize the relation to the MAX phases and the parallel with graphene. Since their discovery in 2011, MXenes have rapidly become established as a novel class of 2D materials with remarkable possibilities for composition variations and property tuning. This article gives a brief overview of MAX phases and MXene from a thin-film perspective, reviewing theory, characterization by electron microscopy, properties and how these are affected by the change in dimensionality, and outstanding challenges.

    Fulltekst (pdf)
    fulltext
  • 9.
    Gharavi, Mohammad Amin
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Kerdsongpanya, Sit
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Rensselaer Polytech Inst, NY 12180 USA.
    Schmidt, Susann
    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.
    Nong, N. V
    Tech Univ Denmark, Denmark.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Balke, B.
    Johannes Gutenberg Univ Mainz, Germany.
    Fournier, D.
    UPMC Univ Paris 06, France.
    Belliard, L.
    UPMC Univ Paris 06, France.
    Le Febvrier, Arnaud
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Pallier, Camille
    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.
    Microstructure and thermoelectric properties of CrN and CrN/Cr2N thin films2018Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 51, nr 35, artikkel-id 355302Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    CrN thin films with an N/Cr ratio of 95% were deposited by reactive magnetron sputtering onto (0001) sapphire substrates. X-ray diffraction and pole figure texture analysis show CrN (111) epitaxial growth in a twin domain fashion. By changing the nitrogen versus argon gas flow mixture and the deposition temperature, thin films with different surface morphologies ranging from grainy rough textures to flat and smooth films were prepared. These parameters can also affect the CrN(x )system, with the film compound changing between semiconducting CrN and metallic Cr2N through the regulation of the nitrogen content of the gas flow and the deposition temperature at a constant deposition pressure. Thermoelectric measurements (electrical resistivity and Seebeck coefficient), scanning electron microscopy, and transmission electron microscopy imaging confirm the changing electrical resistivity between 0.75 and 300 m omega cm, the changing Seebeck coefficient values between 140 and 230 mu VK-1, and the differences in surface morphology and microstructure as higher temperatures result in lower electrical resistivity while gas flow mixtures with higher nitrogen content result in single phase cubic CrN.

    Fulltekst (pdf)
    fulltext
  • 10. Gogova, D.
    et al.
    Hemmingsson, Carl
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Monemar, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Talik, E.
    Kruczek, M.
    Tuomisto, F.
    Saarinen, K.
    Investigation of the structural and optical properties of free-standing GaN grown by HVPE2005Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 38, nr 14, s. 2332-2337Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The potential of the high-growth rate hydride vapour phase epitaxy technique and laser lift-off for the fabrication of free-standing GaN substrates is explored. Structural and optical properties of 300 νm thick free-standing GaN have been investigated employing different analytical techniques. The x-ray diffraction (XRD) measurements prove good crystalline quality of the material grown. A comparatively low value of (3 ± 1) × 1016 cm-3 of Ga vacancy-related defects is inferred from positron annihilation spectroscopy data. Complete strain relaxation is observed on the Ga-polar face of the free-standing GaN by XRD and Raman spectroscopy measurements. The strain-free homoepitaxy will significantly reduce the defect density, and thus an improvement of the device performance and lifetime can be realized. © 2005 IOP Publishing Ltd.

  • 11.
    Greczynski, Grzegorz
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Rhein Westfal TH Aachen, Germany.
    Mraz, S.
    Rhein Westfal TH Aachen, Germany.
    Schneider, J. M.
    Rhein Westfal TH Aachen, Germany.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Substantial difference in target surface chemistry between reactive dc and high power impulse magnetron sputtering2018Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 51, nr 5, artikkel-id 05LT01Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The nitride layer formed in the target race track during the deposition of stoichiometric TiN thin films is a factor 2.5 thicker for high power impulse magnetron sputtering (HIPIMS), compared to conventional dc processing (DCMS). The phenomenon is explained using x-ray photoelectron spectroscopy analysis of the as-operated Ti target surface chemistry supported by sputter depth profiles, dynamic Monte Carlo simulations employing the TRIDYN code, and plasma chemical investigations by ion mass spectrometry. The target chemistry and the thickness of the nitride layer are found to be determined by the implantation of nitrogen ions, predominantly N+ and N-2(+) for HIPIMS and DCMS, respectively. Knowledge of this method-inherent difference enables robust processing of high quality functional coatings.

    Fulltekst (pdf)
    fulltext
  • 12.
    Gunnarsson, Rickard
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Brenning, Nils
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten. KTH Royal Inst Technol, Sweden.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Nucleation of titanium nanoparticles in an oxygen-starved environment. I: experiments2018Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 51, nr 45, artikkel-id 455201Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A constant supply of oxygen has been assumed to be necessary for the growth of titanium nanoparticles by sputtering. This oxygen supply can arise from a high background pressure in the vacuum system or from a purposely supplied gas. The supply of oxygen makes it difficult to grow metallic nanoparticles of titanium and can cause process problems by reacting with the target. We here report that growth of titanium nanoparticles in the metallic hexagonal titanium (alpha Ti) phase is possible using a pulsed hollow cathode sputter plasma and adding a high partial pressure of helium to the process instead of trace amounts of oxygen. The helium cools the process gas in which the nanoparticles nucleate. This is important both for the first dimer formation and the continued growth to a thermodynamically stable size. The parameter region, inside which the synthesis of nanoparticles is possible, is mapped out experimentally and the theory of the physical processes behind this process window is outlined. A pressure limit below which no nanoparticles were produced was found at 200 Pa, and could be attributed to a low dimer formation rate, mainly caused by a more rapid dilution of the growth material. Nanoparticle production also disappeared at argon gas flows above 25 sccm. In this case, the main reason was identified as a gas temperature increase within the nucleation zone, giving a too high evaporation rate from nanoparticles (clusters) in the stage of growth from dimers to stable nuclei. These two mechanisms are in depth explored in a companion paper. A process stability limit was also found at low argon gas partial pressures, and could be attributed to a transition from a hollow cathode discharge to a glow discharge.

    Fulltekst (pdf)
    fulltext
  • 13.
    Gunnarsson, Rickard
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Brenning, Nils
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten. KTH Royal Inst Technol, Sweden.
    Ojamäe, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Kalered, Emil
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Raadu, Michael Allan
    KTH Royal Inst Technol, Sweden.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Nucleation of titanium nanoparticles in an oxygen-starved environment. II: theory2018Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 51, nr 45, artikkel-id 455202Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The nucleation and growth of pure titanium nanoparticles in a low-pressure sputter plasma has been believed to be essentially impossible. The addition of impurities, such as oxygen or water, facilitates this and allows the growth of nanoparticles. However, it seems that this route requires such high oxygen densities that metallic nanoparticles in the hexagonal alpha Ti-phase cannot be synthesized. Here we present a model which explains results for the nucleation and growth of titanium nanoparticles in the absent of reactive impurities. In these experiments, a high partial pressure of helium gas was added which increased the cooling rate of the process gas in the region where nucleation occurred. This is important for two reasons. First, a reduced gas temperature enhances Ti-2 dimer formation mainly because a lower gas temperature gives a higher gas density, which reduces the dilution of the Ti vapor through diffusion. The same effect can be achieved by increasing the gas pressure. Second, a reduced gas temperature has a more than exponential effect in lowering the rate of atom evaporation from the nanoparticles during their growth from a dimer to size where they are thermodynamically stable, r*. We show that this early stage evaporation is not possible to model as a thermodynamical equilibrium. Instead, the single-event nature of the evaporation process has to be considered. This leads, counter intuitively, to an evaporation probability from nanoparticles that is exactly zero below a critical nanoparticle temperature that is size-dependent. Together, the mechanisms described above explain two experimentally found limits for nucleation in an oxygen-free environment. First, there is a lower limit to the pressure for dimer formation. Second, there is an upper limit to the gas temperature above which evaporation makes the further growth to stable nuclei impossible.

    Fulltekst (pdf)
    fulltext
  • 14.
    Gylfason, K. B.
    et al.
    Science Institute, University of Iceland, Reykjavik, Iceland.
    Alami, Jones
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska högskolan.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska högskolan.
    Gudmundsson, J. T.
    Science Institute, University of Iceland, Reykjavik, Iceland.
    Ion-accoustic solitary waves in a high power pulsed magnetron sputtering discharge2005Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 38, nr 18, s. 3417-3421Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on the creation and propagation of ion-acoustic solitary waves in a high power pulsed magnetron sputtering discharge. A dense localized plasma is created by applying high energy pulses (4–12 J) of length 70 µs, at a repetition frequency of 50 pulses per second, to a planar magnetron sputtering source. The temporal behaviour of the electron density, measured by a Langmuir probe, shows solitary waves travelling away from the magnetron target. The velocity of the waves depends on the gas pressure but is roughly independent of the pulse energy.

  • 15.
    Huo, Chunqing
    et al.
    KTH Royal Institute Technology, Sweden; Hainan University, Peoples R China.
    Lundin, D.
    University of Paris Saclay, France.
    Gudmundsson, J. T.
    KTH Royal Institute Technology, Sweden; University of Paris Saclay, France; University of Iceland, Iceland.
    Raadu, M. A.
    KTH Royal Institute Technology, Sweden.
    Bradley, J. W.
    University of Liverpool, England.
    Brenning, Nils
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten. KTH Royal Institute Technology, Sweden.
    Particle-balance models for pulsed sputtering magnetrons2017Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 50, nr 35, artikkel-id 354003Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The time-dependent plasma discharge ionization region model (IRM) has been under continuous development during the past decade and used in several studies of the ionization region of high-power impulse magnetron sputtering (HiPIMS) discharges. In the present work, a complete description of the most recent version of the IRM is given, which includes improvements, such as allowing for returning of the working gas atoms from the target, a separate treatment of hot secondary electrons, addition of doubly charged metal ions, etc. To show the general applicability of the IRM, two different HiPIMS discharges are investigated. The first set concerns 400 mu s long discharge pulses applied to an Al target in an Ar atmosphere at 1.8 Pa. The second set focuses on 100 mu s long discharge pulses applied to a Ti target in an Ar atmosphere at 0.54 Pa, and explores the effects of varying the magnetic field strength. The model results show that Al2+-ions contribute negligibly to the production of secondary electrons, while Ti2+-ions effectively contribute to the production of secondary electrons. Similarly, the model results show that for an argon discharge with Al target the contribution of Al+-ions to the discharge current at the target surface is over 90% at 800 V. However, at 400 V the Al+-ions and Ar+-ions contribute roughly equally to the discharge current in the initial peak, while in the plateau region Ar+-ions contribute to roughly 2/3 of the current. For high currents the discharge with Al target develops almost pure self-sputter recycling, while the discharge with Ti target exhibits close to a 50/50 combination of self-sputter recycling and working gas-recycling. For a Ti target, a self-sputter yield significantly below unity makes working gas-recycling necessary at high currents. For the discharge with Ti target, a decrease in the B-field strength, resulted in a corresponding stepwise increase in the discharge resistivity.

  • 16.
    Hänninen, Tuomas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Schmidt, Susann
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Wissting, Jonas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Jensen, 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.
    Högberg, Hans
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Stoichiometric silicon oxynitride thin films reactively sputtered in Ar/N2O plasmas by HiPIMS2016Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 49, nr 13, artikkel-id 135309Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Silicon oxynitride (SiOxNy, x = 0.2 − 1.3, y = 0.2 − 0.7) thin films were synthesized by reactive high power impulse magnetron sputtering from a pure silicon target in Ar/N2O atmospheres. It is found that the composition of the material can be controlled by the reactive gas flow and the average target power. X-ray photoelectron spectroscopy (XPS) shows that high average powers result in more silicon-rich films, while lower target powers yield silicon-oxide-like material due to more pronounced target poisoning. The amount of nitrogen in the films can be controlled by the percentage of nitrous oxide in the working gas. The nitrogen content remains at a constant level while the target is operated in the transition region between metallic and poisoned target surface conditions. The extent of target poisoning is gauged by the changes in peak target current under the different deposition conditions. XPS also shows that varying concentrations and ratios of oxygen and nitrogen in the films result in film chemical bonding structures ranging from silicon-rich to stoichiometric silicon oxynitrides having no observable Si−Si bond contributions. Spectroscopic ellipsometry shows that the film optical properties depend on the amount and ratio of oxygen and nitrogen in the compound, with film refractive indices measured at 633 nm ranging between those of SiO2 and Si3N4.

  • 17.
    Jiang, Kaiyun
    et al.
    RWTH Aachen University, Germany.
    Sarakinos, Kostas
    Materials Chemistry, RWTH Aachen University, Germany.
    Konstantinidis, Stephanos
    RWTH Aachen University, Germany.
    Schneider, Jochen M.
    RWTH Aachen University, Germany.
    Low temperature synthesis of alpha-Al(2)O(3) films by high-power plasma-assisted chemical vapour deposition2010Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 43, nr 32, s. 325202-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, we deposit Al(2)O(3) films using plasma-assisted chemical vapour deposition (PACVD) in an Ar-H(2)-O(2)-AlCl(3) atmosphere. A novel generator delivering approximately 4 times larger power densities than those conventionally employed in PACVD enabling efficient AlCl(3) dissociation in the gas phase as well as a more intense energetic bombardment of the growing film is utilized. We demonstrate that these deposition conditions allow for the growth of dense alpha-Al(2)O(3) films with negligible Cl incorporation and elastic properties similar to those of the bulk alpha-Al(2)O(3) at a temperature of 560 +/- 10 degrees C.

  • 18.
    Katnagallu, Shyam
    et al.
    Max Planck Inst Eisenforsch GmbH, Germany.
    Dagan, Michal
    Univ Oxford, England.
    Parviainen, Stefan
    Normandie Univ, France.
    Nematollahi, Ali
    Max Planck Inst Eisenforsch GmbH, Germany.
    Grabowski, Blazej
    Max Planck Inst Eisenforsch GmbH, Germany.
    Bagot, Paul A. J.
    Univ Oxford, England.
    Rolland, Nicolas
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska fakulteten.
    Neugebauer, Joerg
    Max Planck Inst Eisenforsch GmbH, Germany.
    Raabe, Dierk
    Max Planck Inst Eisenforsch GmbH, Germany.
    Vurpillot, Francois
    Normandie Univ, France.
    Moody, Michael P.
    Univ Oxford, England.
    Gault, Baptiste
    Max Planck Inst Eisenforsch GmbH, Germany.
    Impact of local electrostatic field rearrangement on field ionization2018Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 51, nr 10, artikkel-id 105601Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Field ion microscopy allows for direct imaging of surfaces with true atomic resolution. The high charge density distribution on the surface generates an intense electric field that can induce ionization of gas atoms. We investigate the dynamic nature of the charge and the consequent electrostatic field redistribution following the departure of atoms initially constituting the surface in the form of an ion, a process known as field evaporation. We report on a new algorithm for image processing and tracking of individual atoms on the specimen surface enabling quantitative assessment of shifts in the imaged atomic positions. By combining experimental investigations with molecular dynamics simulations, which include the full electric charge, we confirm that change is directly associated with the rearrangement of the electrostatic field that modifies the imaging gas ionization zone. We derive important considerations for future developments of data reconstruction in 3D field ion microscopy, in particular for precise quantification of lattice strains and characterization of crystalline defects at the atomic scale.

  • 19.
    Khan, Azam
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Hussain, Mushtaque
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Mechanical and piezoelectric properties of zinc oxide nanorods grown on conductive textile fabric as an alternative substrate2014Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 47, nr 34, s. 345102-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The present research is devoted to understanding the mechanism and causes of variation in the piezoelectric potential generated from vertically aligned zinc oxide (ZnO) nanorods (NRs), which were grown on a conductive textile fabric as an alternative substrate by using the aqueous chemical growth method. The piezoelectric voltage was harvested from vertically aligned ZnO NRs having different physical parameters by using atomic force microscopy in contact mode and the variation in the generated piezoelectricity was investigated. The generated output potential indicates that different physical parameters such aspect ratio, crystal size and lattice internal crystal strain have a strong influence on the piezoelectric properties of vertically aligned ZnO NRs, which were grown on a textile fabric. Presented results indicate that textiles can be used as an alternative substrate just like the other conventional substrates, because our results are similar/better than many reported works on conventional substrates.

  • 20.
    Kimel, Alexey
    et al.
    Radboud Univ Nijmegen, Netherlands.
    Zvezdin, Anatoly
    Russian Acad Sci, Russia.
    Sharma, Sangeeta
    Max Born Inst Nichtlineare Opt & Kurzzeitspektros, Germany.
    Shallcross, Samuel
    Max Born Inst Nichtlineare Opt & Kurzzeitspektros, Germany.
    de Sousa, Nuno
    Donostia Int Phys Ctr DIPC, Spain.
    Garcia-Martin, Antonio
    CEI UAM CSIC, Spain.
    Salvan, Georgeta
    Tech Univ Chemnitz, Germany.
    Hamrle, Jaroslav
    Charles Univ Prague, Czech Republic.
    Stejskal, Ondrej
    Charles Univ Prague, Czech Republic.
    McCord, Jeffrey
    Univ Kiel, Germany.
    Tacchi, Silvia
    Univ Perugia, Italy.
    Carlotti, Giovanni
    Univ Perugia, Italy.
    Gambardella, Pietro
    Swiss Fed Inst Technol, Switzerland.
    Salis, Gian
    IBM Res Zurich, Switzerland.
    Muenzenberg, Markus
    Univ Greifswald, Germany.
    Schultze, Martin
    Graz Univ Technol, Austria.
    Temnov, Vasily
    CNRS, France.
    Bychkov, Igor V
    Chelyabinsk State Univ, Russia.
    Kotov, Leonid N.
    Syktyvkar State Univ, Russia.
    Maccaferri, Nicolo
    Umea Univ, Sweden; Univ Luxembourg, Luxembourg.
    Ignatyeva, Daria
    Russian Quantum Ctr, Russia; VI Vernadsky Crimean Fed Univ, Russia; Lomonosov Moscow State Univ, Russia.
    Belotelov, Vladimir
    Russian Quantum Ctr, Russia; VI Vernadsky Crimean Fed Univ, Russia; Lomonosov Moscow State Univ, Russia.
    Donnelly, Claire
    Max Planck Inst Chem Phys Solids, Germany.
    Rodriguez, Aurelio Hierro
    Univ Oviedo, Spain; Univ Oviedo, Spain.
    Matsuda, Iwao
    Univ Tokyo, Japan.
    Ruchon, Thierry
    Univ Paris Saclay, France.
    Fanciulli, Mauro
    CY Cergy Paris Univ, France; Sorbonne Univ, France.
    Sacchi, Maurizio
    Synchrotron SOLEIL, France.
    Du, Chunhui Rita
    Univ Calif San Diego, CA 92093 USA; Univ Calif San Diego, CA 92093 USA.
    Wang, Hailong
    Univ Calif San Diego, CA 92093 USA.
    Armitage, N. Peter
    Johns Hopkins Univ, MD 21210 USA.
    Schubert, Mathias
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten. Univ Nebraska, NE 68588 USA.
    Darakchieva, Vanya
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten. Lund Univ, Sweden.
    Liu, Bilu
    Tsinghua Univ, Peoples R China; Tsinghua Univ, Peoples R China.
    Huang, Ziyang
    Tsinghua Univ, Peoples R China; Tsinghua Univ, Peoples R China.
    Ding, Baofu
    Tsinghua Univ, Peoples R China; Tsinghua Univ, Peoples R China; Chinese Acad Sci, Peoples R China.
    Berger, Andreas
    CIC nanoGUNE BRTA, Spain.
    Vavassori, Paolo
    CIC nanoGUNE BRTA, Spain; IKERBASQUE, Spain.
    The 2022 magneto-optics roadmap2022Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 55, nr 46, artikkel-id 463003Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Magneto-optical (MO) effects, viz. magnetically induced changes in light intensity or polarization upon reflection from or transmission through a magnetic sample, were discovered over a century and a half ago. Initially they played a crucially relevant role in unveiling the fundamentals of electromagnetism and quantum mechanics. A more broad-based relevance and wide-spread use of MO methods, however, remained quite limited until the 1960s due to a lack of suitable, reliable and easy-to-operate light sources. The advent of Laser technology and the availability of other novel light sources led to an enormous expansion of MO measurement techniques and applications that continues to this day (see section 1). The here-assembled roadmap article is intended to provide a meaningful survey over many of the most relevant recent developments, advances, and emerging research directions in a rather condensed form, so that readers can easily access a significant overview about this very dynamic research field. While light source technology and other experimental developments were crucial in the establishment of todays magneto-optics, progress also relies on an ever-increasing theoretical understanding of MO effects from a quantum mechanical perspective (see section 2), as well as using electromagnetic theory and modelling approaches (see section 3) to enable quantitatively reliable predictions for ever more complex materials, metamaterials, and device geometries. The latest advances in established MO methodologies and especially the utilization of the MO Kerr effect (MOKE) are presented in sections 4 (MOKE spectroscopy), 5 (higher order MOKE effects), 6 (MOKE microscopy), 8 (high sensitivity MOKE), 9 (generalized MO ellipsometry), and 20 (Cotton-Mouton effect in two-dimensional materials). In addition, MO effects are now being investigated and utilized in spectral ranges, to which they originally seemed completely foreign, as those of synchrotron radiation x-rays (see section 14 on three-dimensional magnetic characterization and section 16 on light beams carrying orbital angular momentum) and, very recently, the terahertz (THz) regime (see section 18 on THz MOKE and section 19 on THz ellipsometry for electron paramagnetic resonance detection). Magneto-optics also demonstrates its strength in a unique way when combined with femtosecond laser pulses (see section 10 on ultrafast MOKE and section 15 on magneto-optics using x-ray free electron lasers), facilitating the very active field of time-resolved MO spectroscopy that enables investigations of phenomena like spin relaxation of non-equilibrium photoexcited carriers, transient modifications of ferromagnetic order, and photo-induced dynamic phase transitions, to name a few. Recent progress in nanoscience and nanotechnology, which is intimately linked to the achieved impressive ability to reliably fabricate materials and functional structures at the nanoscale, now enables the exploitation of strongly enhanced MO effects induced by light-matter interaction at the nanoscale (see section 12 on magnetoplasmonics and section 13 on MO metasurfaces). MO effects are also at the very heart of powerful magnetic characterization techniques like Brillouin light scattering and time-resolved pump-probe measurements for the study of spin waves (see section 7), their interactions with acoustic waves (see section 11), and ultra-sensitive magnetic field sensing applications based on nitrogen-vacancy centres in diamond (see section 17). Despite our best attempt to represent the field of magneto-optics accurately and do justice to all its novel developments and its diversity, the research area is so extensive and active that there remains great latitude in deciding what to include in an article of this sort, which in turn means that some areas might not be adequately represented here. However, we feel that the 20 sections that form this 2022 magneto-optics roadmap article, each written by experts in the field and addressing a specific subject on only two pages, provide an accurate snapshot of where this research field stands today. Correspondingly, it should act as a valuable reference point and guideline for emerging research directions in modern magneto-optics, as well as illustrate the directions this research field might take in the foreseeable future.

    Fulltekst (pdf)
    fulltext
  • 21.
    Kyutt, R N
    et al.
    Ioffe Physico-Technical Institute of RAS, St. Petersburg.
    Shubina, T V
    Ioffe Physico-Technical Institute of RAS, St. Petersburg.
    Sorokin, S V
    Ioffe Physico-Technical Institute of RAS, St. Petersburg.
    Solnyshkov, DD
    RAS.
    Ivanov, S V
    Ioffe Physico-Technical Institute of RAS, St. Petersburg.
    Willander, Magnus
    Chalmers.
    X-ray diffraction determination of the interface structure of CdSe/BeTe superlattices2003Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 36, nr 10A, s. A166-A171Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Structural study of CdSe/BeTe superlattices (SLs) grown by molecular beam epitaxy on GaAs substrate was performed by using double and triple crystal x-ray diffractometry. The period of the studied structures was about 5 nm, while the thickness of thin CdSe insertions varied from 0.4 to 1.5 monolayer. It is shown that new Be-Se bonds arise at the BeTe-CdSe interfaces in addition to the Be-Se bonds expected at the CdSe-BeTe interfaces. From the analysis of the diffraction curves of 002-reflection the complex composition of interfaces and thin insertions has been determined and contribution of all types of bonds in each SL period calculated. The diffraction curves of 004-reflection were used for the specification of the fine structure of the interfaces.

  • 22.
    Le Febvrier, Arnaud
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Tureson, Nina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Stilkerich, Nina
    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.
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Effect of impurities on morphology, growth mode, and thermoelectric properties of (111) and (001) epitaxial-like ScN films2019Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 52, nr 3, artikkel-id 035302Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    ScN is an emerging semiconductor with an indirect bandgap. It has attracted attention for its thermoelectric properties, use as seed layers, and for alloys for piezoelectric application. ScN and other transition metal nitride semiconductors used for their interesting electrical properties are sensitive to contaminants, such as oxygen or fluorine. In this present article, the influence of depositions conditions on the amount of oxygen contaminants incorporated in ScN films were investigated and their effects on the electrical properties (electrical resistivity and Seebeck coefficient) were studied. Epitaxial-like films of thickness 125 +/- 5 nm to 155 +/- 5 nm were deposited by DC-magnetron sputtering on c-plane Al-2, O-3(111) and r-plane Al2O3 at substrate temperatures ranging from 700 degrees C to 950 degrees C. The amount of oxygen contaminants in the film, dissolved into ScN or as an oxide, was related to the adatom mobility during growth, which is affected by the deposition temperature and the presence of twin domain growth. The lowest values of electrical resistivity of 50 mu Omega cm were obtained on ScN(1 1 1)/ MgO(111) and on ScN(001)/r-plane Al2O3 grown at 950 degrees C with no twin domains and the lowest amount of oxygen contaminant. At the best, the films exhibited an electrical resistivity of 50 mu Omega cm with Seebeck coefficient values maintained at -40 mu V K-1, thus a power factor estimated at 3.2 x 10(-3) W m(-1) K-2 (at room temperature).

    Fulltekst (pdf)
    fulltext
  • 23.
    Magnfält, Daniel
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska högskolan.
    Elofsson, Viktor
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska högskolan.
    Abadias, G
    Institut P', Département Physique et Mécanique des Matériaux, Université de Poitiers-CNRS-ENSMA, SP2MI, Téléport 2, Bd M. et P. Curie, F-86962 Chasseneuil-Futuroscope, France.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska högskolan.
    Sarakinos, Kostas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska högskolan.
    Time-domain and energetic bombardment effects on the nucleation and coalescence of thin metal films on amorphous substrates2013Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 46, nr 21, artikkel-id 215303Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Pulsed, ionized vapour fluxes, generated from high power impulse magnetron sputtering (HiPIMS) discharges, are employed to study the effects of time-domain and energetic bombardment on the nucleation and coalescence characteristics during Volmer–Weber growth of metal (Ag) films on amorphous (SiO2) substrates. In situ monitoring of the film growth, by means of wafer curvature measurements and spectroscopic ellipsometry, is used to determine the film thickness where a continuous film is formed. This thickness decreases from ~210 to ~140 Å when increasing the pulsing frequency for a constant amount of material deposited per pulse or when increasing the amount of material deposited per pulse and the energy of the film forming species for a constant pulsing frequency. Estimations of adatom lifetimes and the coalescence times show that there are conditions at which these times are within the range of the modulation of the vapour flux. Thus, nucleation and coalescence processes can be manipulated by changing the temporal profile of the vapour flux. We suggest that other than for elucidating the atomistic mechanisms that control pulsed growth processes, the interplay between the time scales for diffusion, coalescence and vapour flux pulsing can be used as a tool to determine characteristic surface diffusion and island coalescence parameters.

    Fulltekst (pdf)
    fulltext
  • 24. Mayrhofer, P H
    et al.
    Willmann, Herbert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Hultman, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Mitterer, C
    Influence of different atmospheres on the thermal decomposition of Al-Cr-N coatings2008Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 41, nr 15Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Metastable cubic (c) AlCrN coatings decompose during thermal annealing into their stable phases Cr and hexagonal (h) AlN under the release of N 2. We show that the onset temperature To and amount of N2 release depend on the ambient atmosphere. For c-Al 0.56Cr0.44N only a partial dissociation into h-AlN and h-Cr2N with To ∼ 1180°C occurs during annealing in N2 up to 1450°C. Experiments in synthetic air to 1450°C yield a complete oxidation to (Al0.56Cr0.44) 2O3. © 2008 IOP Publishing Ltd.

  • 25.
    Muhammad, Junaid
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Sandström, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Darakchieva, Vanya
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hsiao, Ching-Lien
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Persson, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Stress Evolution during Growth of GaN (0001)/Al2O3 (0001) by Reactive DC Magnetron Sputter Epitaxy2014Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 47, nr 14, s. 145301-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We study the real time stress evolution, by in-situ curvature measurements, during magnetron sputter epitaxy of GaN (0001) epilayers at different growth temperatures, directly on Al2O3 (0001) substrates. The epilayers are grown by sputtering from a liquid Ga target in a mixed N2/Ar discharge. For 600 °C, a tensile biaxial stress evolution is observed, while for 700 °C and 800 °C, compressive stress evolutions are observed. Structural characterization by crosssectional transmission electron microscopy, and atomic force microscopy revealed that films grew at 700 °C and 800 °C in a layer-by-layer mode while a growth temperature of 600 °C led to an island growth mode. High resolution Xray diffraction data showed that edge and screw threading dislocation densities decreased with increasing growth temperature with a total density of 5.5×1010 cm-2. The observed stress evolution and growth modes are explained by a high adatom mobility during magnetron sputter epitaxy at 700 - 800 °C. Also other possible reasons for the different stress evolutions are discussed.

  • 26.
    Nilsson, Daniel
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Kakanakova-Georgieva, Anelia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Lattice parameters, structural and optical properties of AlN true bulk, homoepitaxial and heteroepitaxial material grown at high temperatures of up to 1400 °C2016Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 49, nr 17Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The lattice parameters and residual strain of homo- and heteroepitaxial AlN layers grown at elevated process temperatures (1200-1400 °C) by hot-wall MOCVD are studied. The average lattice parameters for the homoepitaxial AlN layers grown on true bulk AlN substrates are determined to be a = 3.1113 ± 0.0001 Å and c = 4.9808 ± 0.0001 Å are discussed in relation to previously published data. The lattice parameters measured from biaxially strained AlN layers grown on SiC are used to determine the biaxial strain relaxation coefficient to be RB = -0.556 ± 0.021. The structural and optical quality of the heteroepitaxial layers improved with increasing layer thickness and at a thickness of 1.3 μm, crack-free AlN of high crystalline quality with full widths at half maximum of the (0002) and (1012) rocking curves of 25 arc sec and 372 arc sec, respectively, were obtained. Tensile strain developed with increasing layer thickness despite the higher crystalline quality of these layers. This can be explained by the thermal mismatch between the AlN and SiC in combination with island coalescence at the initial stage and/or during the growth.

  • 27.
    Pilch, Iris
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Caillault, L.
    University of Paris 11, France.
    Minea, T.
    University of Paris 11, France.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Tal, Alexey
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten. National University of Science and Technology MISIS, Russia.
    Abrikosov, Igor
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten. National University of Science and Technology MISIS, Russia.
    Münger, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Brenning, Nils
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten. KTH Royal Institute Technology, Sweden.
    Nanoparticle growth by collection of ions: orbital motion limited theory and collision-enhanced collection2016Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 49, nr 39, s. 395208-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The growth of nanoparticles in plasma is modeled for situations where the growth is mainly due to the collection of ions of the growth material. The model is based on the classical orbit motion limited (OML) theory with the addition of a collision-enhanced collection (CEC) of ions. The limits for this type of model are assessed with respect to three processes that are not included: evaporation of the growth material, electron field emission, and thermionic emission of electrons. It is found that both evaporation and thermionic emission can be disregarded below a temperature that depends on the nanoparticle material and on the plasma parameters; for copper in our high-density plasma this limit is about 1200 K. Electron field emission can be disregarded above a critical nanoparticle radius, in our case around 1.4 nm. The model is benchmarked, with good agreement, to the growth of copper nanoparticles from a radius of 5 nm-20 nm in a pulsed power hollow cathode discharge. Ion collection by collisions contributes with approximately 10% of the total current to particle growth, in spite of the fact that the collision mean free path is four orders of magnitude longer than the nanoparticle radius.

    Fulltekst (pdf)
    fulltext
  • 28.
    Popok, V.N.
    et al.
    Department of Physics, University of Gothenburg, Sweden.
    Jensen, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Vuckovic, S.
    Department of Physics, University of Gothenburg, Sweden.
    Mackova, A.
    Nuclear Physics Institute of ASCR, Czech Republic.
    Trautmann, C.
    GSI Helmholtzzentrum, Darmstadt, Germany.
    Formation of surface nanostructures on rutile (TiO2): comparative study of low-energy cluster ion and high-energy monoatomic ion impact2009Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 42, nr 20, s. 205303-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The formation of nanostructures on rutile (TiO2) surfaces formed after the implantation of kiloelectronvolt-energy Ar+n cluster ions and megaelectronvolt- to gigaelectronvolt-energy multiply charged heavy ions (Iq+, Taq+ and Uq+) is studied. Despite the differences in stopping and energy transfer mechanisms between the kiloelectronvolt-energy cluster ions and megaelectronvolt-energy monoatomic ions, their impacts lead to a similar type of surface damage, namely craters. For the cluster ion implantation the craters are caused by the multiple-collision effect (dominated by nuclear stopping) and the high density of energy and momentum transferred to the target, while for the case of megaelectronvolt multiply charged ions the craters are probably formed due to the Coulomb explosion and fast energy transfer caused by the electronic stopping. At ion energies in the gigaelectronvolt range, nanosize protrusions, so-called hillocks, are observed on the surface. It is suggested that electronic stopping leads to the formation of continuous tracks and the transferred energy is high enough to melt the material along the whole projectile path. Elastic rebound of the tension between the molten and solid state phases leads to liquid flow, expansion and quenching of the melt, thus forming the hillocks. Atomic force microscopy measurements carried out under different environmental conditions (temperature and atmosphere) suggest that the damaged material at the nanosize impact spots has very different water affinity properties (higher hydrophilicity or water adsorption) compared with the non-irradiated rutile surface.

  • 29.
    Ratnikov, VV
    et al.
    RAS, Ioffe Inst, St Petersburg 194021, Russia Linkoping Univ, S-58183 Linkoping, Sweden.
    Kyutt, RN
    RAS, Ioffe Inst, St Petersburg 194021, Russia Linkoping Univ, S-58183 Linkoping, Sweden.
    Shubina, Tatiana
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Paskova, Tanja
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Monemar, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Determination of microdistortion components and their application to structural characterization of HVBE GaN epitaxial layers2001Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 34, nr 10A, s. A30-A34Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The dislocation structure of hydride vapour phase epitaxial thick GaN layers grown on sapphire is studied by analysis of the microdistortion tenser components. Symmetrical reflections (including reflections from planes forming large angles with the basal plane) with two modes of scanning (theta and theta -2 theta) in two geometries (Bragg and Lane) are used to obtain the tenser components. The instant connections between the tenser components and major dislocation types are specified. Different types of dislocation distributions have been identified in the thick GaN films grown on sapphire without and with undoped and Si-doped metal-organic chemical vapour deposited templates.

  • 30.
    Rosen, Johanna
    et al.
    Rhein Westfal TH Aachen.
    Anders, A
    Lawrence Berkeley Laboratory.
    Time and material dependence of the voltage noise generated by cathodic vacuum arcs2005Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 38, nr 23, s. 4184-4190Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The high frequency fluctuations of the burning voltage of cathodic vacuum arcs have been investigated in order to extract information on cathode processes, especially concerning evolution in time after arc ignition. Eight cathode materials (W, Ta, Hf, Ti, Ni, An, Sn, Bi) were selected covering a wide range of cohesive energy. The voltage noise was recorded using both a broad-band voltage divider and an attenuator connected to a fast oscilloscope (limits 1 GHz analog and 5 GS s(-1) digital). Fast Fourier transform revealed a power spectrum that is linear in log-log presentation, with a slope of 1/f(2), where f is the frequency (brown noise). The amplitude of the spectral power of the voltage noise was found to scale with the cohesive energy, in agreement with earlier measurements at lower resolution. These basic results do not depend on the time after arc initiation. However, lower arc current in the beginning of the pulse shows greater voltage noise, suggesting an inverse relation between the noise amplitude and number of emission sites (cathode spot fragments).

  • 31.
    Rudolph, M.
    et al.
    Leibniz Inst Surface Engn IOM, Germany.
    Brenning, Nils
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten. KTH Royal Inst Technol, Sweden.
    Hajihoseini, H.
    Univ Twente, Netherlands.
    Raadu, M. A.
    KTH Royal Inst Technol, Sweden.
    Minea, T. M.
    Univ Paris Saclay, France.
    Anders, A.
    Leibniz Inst Surface Engn IOM, Germany; Univ Leipzig, Germany.
    Gudmundsson, J. T.
    KTH Royal Inst Technol, Sweden; Univ Iceland, Iceland.
    Lundin, Daniel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Influence of the magnetic field on the discharge physics of a high power impulse magnetron sputtering discharge2022Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 55, nr 1, artikkel-id 015202Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The magnetic field is a key feature that distinguishes magnetron sputtering from simple diode sputtering. It effectively increases the residence time of electrons close to the cathode surface and by that increases the energy efficiency of the discharge. This becomes apparent in high power impulse magnetron sputtering (HiPIMS) discharges, as small changes in the magnetic field can result in large variations in the discharge characteristics, notably the peak discharge current and/or the discharge voltage during a pulse. Here, we analyze the influence of the magnetic field on the electron density and temperature, how the discharge voltage is split between the cathode sheath and the ionization region, and the electron heating mechanism in a HiPIMS discharge. We relate the results to the energy efficiency of the discharge and discuss them in terms of the probability of target species ionization. The energy efficiency of the discharge is related to the fraction of pulse power absorbed by the electrons. Ohmic heating of electrons in the ionization region leads to higher energy efficiency than electron energization in the sheath. We find that the electron density and ionization probability of the sputtered species depend largely on the discharge current. The results suggest ways to adjust electron density and electron temperature using the discharge current and the magnetic field, respectively, and how they influence the ionization probability.

    Fulltekst (pdf)
    fulltext
  • 32.
    Sarakinos, Kostas
    et al.
    Institute of Physics (IA), RWTH Aachen University, Germany.
    Alami, J.
    University of Aachen, Germany.
    Dukwen, J.
    University of Aachen, Germany.
    Woerdenweber, J.
    University of Aachen, Germany.
    Wuttig, M.
    University of Aachen, Germany.
    A semi-quantitative model for the deposition rate in non-reactive high power pulsed magnetron sputtering2008Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 41, nr 21, s. 215301-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A theoretical treatment of the deposition process in a non-reactive high power pulsed magnetron sputtering discharge is presented. This leads to the development of a semi-quantitative model that describes the deposition rate as a function of process parameters, such as the target voltage, the peak target current density, the pulse frequency and the pulse duty cycle. The effect of these parameters on the deposition rate is studied experimentally using carbon, chromium and copper targets. The implementation of the model on the experimental results enables the estimation of the relative fractions of the sputtering gas ions (Ar(+)) and the sputtered metal ions (M(+)) in the total ion flux at the target. The M(+) content in the target ion current is calculated to adopt values up to similar to 72% and similar to 98% for the chromium and the copper targets, respectively. In contrast, the target ion current is found to consist mostly of Ar(+) species in the case of the carbon target. The significantly higher fractions of M(+) ions for chromium and copper are attributed to their higher ionization probability and their higher sputtering yield in comparison with carbon.

  • 33.
    Sarakinos, Kostas
    et al.
    Institute of Physics (IA), Aachen University of Technology, Germany.
    Alami, J.
    Aachen University of Technology, Germany.
    Karimi, P. M.
    Aachen University of Technology, Germany.
    Severin, D.
    Aachen University of Technology, Germany.
    Wuttig, M.
    Aachen University of Technology, Germany.
    The role of backscattered energetic atoms in film growth in reactive magnetron sputtering of chromium nitride2007Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 40, nr 3, s. 778-785Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work the impact of backscattered energetic atoms on film growth in reactive sputtering of CrNx (x less than= 1) is manifested. We use film and plasma characterization techniques, as well as simulations in order to study the dynamics of the target-discharge-film interactions. The results show that the primary bombarding species of the growing film are N-2(+) plasma ions, which are neutralized and backscattered by the target in the form of atomic N. It is shown that the backscattered N atoms have energies which are significantly higher than those of other bombarding species, i.e. the backscattered Ar atoms, the sputtered atoms and the plasma ions. Moreover, it is found that CrN films exhibit compressive stresses of 2.6 GPa and a density close to the bulk value. We attribute these properties to the bombardment by backscattered energetic atoms, in particular N. Pure Cr films are also studied for reference.

  • 34.
    Sarakinos, Kostas
    et al.
    Institute of Physics (IA), Aachen University of Technology, Germany.
    Alami, J.
    Aachen University of Technology, Germany.
    Wuttig, M.
    Aachen University of Technology, Germany.
    Process characteristics and film properties upon growth of TiOx films by high power pulsed magnetron sputtering2007Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 40, nr 7, s. 2108-2114Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work TiOx (x greater than 1.8) films are grown reactively from a ceramic TiO1.8 target employing high power pulsed magnetron sputtering (HPPMS) at a constant average target current. The effect of the pulse on/off time configuration on the target and the discharge characteristics as well as on the film properties is investigated. The target voltage (V-T) increases from 480 to 650V and the peak target current (I-Tp) increases from 2 to 40A when the pulse off-time is increased from 200 to 2450 mu s, while the on-time is kept constant at 50 mu s. This is accompanied by an increase in the number of Ti atoms sputtered from the target, as manifested by time-resolved optical emission spectroscopy (OES) measurements. OES also manifests an increase in the ionization of the sputtered Ti atoms with increasing I-Tp. The above changes in the target and discharge characteristics affect the deposition rate so that the latter increases with increasing I-Tp up to a value of 14 A, above which the deposition rate drops. In all the cases the deposition rates are up to similar to 40% higher compared to the rates achieved for films grown by dc magnetron sputtering (dcMS) which are also studied for reference. The increase in I-Tp from 2 to 40A also affects the films properties. It is shown that a drop in the surface roughness from 1.1 to 0.5 nm takes place. These values are lower than the surface roughness of films grown by dcMS (1.35 nm). Moreover, films grown by HPPMS are found to have higher densities (up to 3.83 g cm(-3)) and higher refractive indices (up to 2.48) in comparison to the films grown by dcMS (3.71 g cm(-3) and 2.38, respectively).

  • 35.
    Schneider, Jochen
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Rohde, S
    Linkoping Univ, Dept Phys, Thin Film Phys Div, S-58183 Linkoping, Sweden Univ Nebraska, Dept Mech Engn, Lincoln, NE 68588 USA React Sputtering Inc, Santa Barbara, CA 93111 USA Univ Hull, Res Ctr Surface Engn, Hull HU6 7RX, N Humberside, England.
    Sproul, WD
    Linkoping Univ, Dept Phys, Thin Film Phys Div, S-58183 Linkoping, Sweden Univ Nebraska, Dept Mech Engn, Lincoln, NE 68588 USA React Sputtering Inc, Santa Barbara, CA 93111 USA Univ Hull, Res Ctr Surface Engn, Hull HU6 7RX, N Humberside, England.
    Matthews, A
    Linkoping Univ, Dept Phys, Thin Film Phys Div, S-58183 Linkoping, Sweden Univ Nebraska, Dept Mech Engn, Lincoln, NE 68588 USA React Sputtering Inc, Santa Barbara, CA 93111 USA Univ Hull, Res Ctr Surface Engn, Hull HU6 7RX, N Humberside, England.
    Recent developments in plasma assisted physical vapour deposition2000Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 33, nr 18, s. R173-R186Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Recent developments in plasma assisted physical vapour deposition (PAPVD) processes an reviewed. A short section on milestones in advances in PAPVD covering the time period from 1938 when the first PAPVD system was patented to the end of the 1980s is followed by a more detailed discussion of some more recent advances, most of which have been related to increases in plasma density. It has been demonstrated that the state of the art PAPVD processes operate in a plasma density range of 10(11) to 10(13) cm(-3). In this range a substantial fraction of the plasma consists of ionized film forming species. Hence, the energy of the condensing film forming species can be directly controlled, as opposed to utilizing indirect energy control with, for example, ionized inert gas bombardment. For a large variety of applications ranging from ceramic film synthesis at conditions far from thermodynamic equilibrium to state of the art metallization technology, such direct energy control of the condensing film forming species is of critical importance, and offers the possibility to engineer the coating microstructure and hence the coating properties.

  • 36.
    Shi, Yuchen
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Jokubavicius, Valdas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Höjer, Pontus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Ivanov, Ivan Gueorguiev
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Yazdi, Gholamreza
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Yakimova, Rositsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Syväjärvi, Mikael
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Sun, Jianwu W.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    A comparative study of high-quality C-face and Si-face 3C-SiC(1 1 1) grown on off-oriented 4H-SiC substrates2019Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 52, nr 34Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a comparative study of the C-face and Si-face of 3C-SiC(111) grown on off-oriented 4H-SiC substrates by the sublimation epitaxy. By the lateral enlargement method, we demonstrate that the high-quality bulk-like C-face 3C-SiC with thickness of ~1 mm can be grown over a large single domain without double positioning boundaries (DPBs), which are known to have a strongly negative impact on the electronic properties of the material. Moreover, the C-face sample exhibits a smoother surface with one unit cell height steps while the surface of the Si-face sample exhibits steps twice as high as on the C-face due to step-bunching. High-resolution XRD and low temperature photoluminescence measurements show that C-face 3C-SiC can reach the same high crystalline quality as the Si-face 3C-SiC. Furthermore, cross-section studies of the C- and Si-face 3C-SiC demonstrate that in both cases an initial homoepitaxial 4H-SiC layer followed by a polytype transition layer are formed prior to the formation and lateral expansion of 3C-SiC layer. However, the transition layer in the C-face sample is extending along the step-flow direction less than that on the Si-face sample, giving rise to a more fairly consistent crystalline quality 3C-SiC epilayer over the whole sample compared to the Si-face 3C-SiC where more defects appeared on the surface at the edge. This facilitates the lateral enlargement of 3C-SiC growth on hexagonal SiC substrates.

    Fulltekst (pdf)
    fulltext
  • 37.
    Shi, Yuchen
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Zakharov, Alexei A.
    MAX IV Lab, Sweden.
    Ivanov, Ivan Gueorguiev
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Vinogradov, Nikolay A.
    MAX IV Lab, Sweden.
    Yazdi, Gholamreza
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Syväjärvi, Mikael
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Yakimova, Rositsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Sun, Jianwu
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    A patterning-free approach for growth of free-standing graphene nanoribbons using step-bunched facets of off-oriented 4H-SiC(0001) epilayers2020Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 53, nr 11, artikkel-id 115102Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The tunable electronic structure of graphene nanoribbons (GNRs) has attracted much attention due to the great potential in nanoscale electronic applications. Most methods to produce GNRs rely on the lithographic process, which suffers from the process-induced disorder in the graphene and scalability issues. Here, we demonstrate a novel approach to directly grow free-standing GNRs on step-bunched facets of off-oriented 4H-SiC epilayers without any patterning or lithography. First, the 4H-SiC epilayers with well-defined bunched steps were intentionally grown on 4 degree off-axis 4H-SiC substrates by the sublimation epitaxy technique. As a result, periodic step facets in-between SiC terraces were obtained. Then, graphene layers were grown on such step-structured 4H-SiC epilayers by thermal decomposition of SiC. Scanning tunneling microscopy (STM) studies reveal that the inclined step facets are about 13-15 nm high and 30-35 nm wide, which gives an incline angle of 23-25 degrees. LEEM and LEED results showed that the terraces are mainly covered by monolayer graphene and the buffer layer underneath it. STM images and the analysis of their Fourier transform patterns suggest that on the facets, in-between terraces, graphene is strongly buckled and appears to be largely decoupled from the surface.

    Fulltekst (pdf)
    fulltext
  • 38.
    Shimizu, Tetsuhide
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten. Tokyo Metropolitan University, Japan.
    Villamayor, Michelle M
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten. University of Philippines Diliman, Philippines.
    Lundin, D.
    University of Paris 11, France.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Process stabilization by peak current regulation in reactive high-power impulse magnetron sputtering of hafnium nitride2016Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 49, nr 6, s. 065202-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A simple and cost effective approach to stabilize the sputtering process in the transition zone during reactive high-power impulse magnetron sputtering (HiPIMS) is proposed. The method is based on real-time monitoring and control of the discharge current waveforms. To stabilize the process conditions at a given set point, a feedback control system was implemented that automatically regulates the pulse frequency, and thereby the average sputtering power, to maintain a constant maximum discharge current. In the present study, the variation of the pulse current waveforms over a wide range of reactive gas flows and pulse frequencies during a reactive HiPIMS process of Hf-N in an Ar-N2 atmosphere illustrates that the discharge current waveform is a an excellent indicator of the process conditions. Activating the reactive HiPIMS peak current regulation, stable process conditions were maintained when varying the N-2 flow from 2.1 to 3.5 sccm by an automatic adjustment of the pulse frequency from 600 Hz to 1150 Hz and consequently an increase of the average power from 110 to 270 W. Hf-N films deposited using peak current regulation exhibited a stable stoichiometry, a nearly constant power-normalized deposition rate, and a polycrystalline cubic phase Hf-N with (1 1 1)-preferred orientation over the entire reactive gas flow range investigated. The physical reasons for the change in the current pulse waveform for different process conditions are discussed in some detail.

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  • 39.
    Sun, Jianwu
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Kamiyama, Satoshi
    Meijo University, Nagoya, Japan.
    Jokubavicius, Valdas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Peyre, H.
    Universite Montpellier 2, France .
    Yakimova, Rositsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Juillaguet, S.
    Universite Montpellier 2, France .
    Syväjärvi, Mikael
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Fluorescent silicon carbide as an ultraviolet-to-visible light converter by control of donor to acceptor recombinations2012Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 45, nr 23, s. 235107-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As an alternative to the conventional phosphors in white LEDs, a donor and acceptor co-doped fluorescent 6H-SiC can be used as an ultraviolet-to-visible light converter without any need of rare-earth metals. From experimental data we provide an explanation to how light can be obtained at room temperature by a balance of the donors and acceptors. A steady-state recombination rate model is used to demonstrate that the luminescence in fluorescent SiC can be enhanced by controlling the donor and acceptor doping levels. A doping criterion for optimization of this luminescence is thus proposed.

    Fulltekst (pdf)
    fulltext
  • 40.
    Svavarsson, HG
    et al.
    Univ Iceland, Inst Sci, IS-107 Reykjavik, Iceland Linkoping Univ, Thin Film Phys Grp, S-58183 Linkoping, Sweden.
    Olafsson, S
    Hellgren, N
    Univ Iceland, Inst Sci, IS-107 Reykjavik, Iceland Linkoping Univ, Thin Film Phys Grp, S-58183 Linkoping, Sweden.
    Helmersson, Ulf
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik.
    Electrostatic powder impact deposition (EPID) of Ge on Si and Cu substrates, microstructure and morphology study2000Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 33, nr 10, s. 1155-1160Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electrostatic powder impact deposition (EPID) is a novel method to deposit thin films by electrostatic acceleration of powder material between charged plates in vacuum. The EPID method has been used to deposit Ce films on Si and Cu substrates at room temperature. Surface morphology and microstructure as studied by SEM showed a very rough surface. XRD and RES measurements revealed that the films were mostly nanocrystalline or amorphous ae oxide. The grain size distribution of the Ge powder was measured before and after deposition. Initial distribution showed a median grain size of 32 mu m and distribution width of 80 mu m. After the deposition the median grain size had decreased to 16 mu m acid the width decreased to 55 mu m. The grain size of the deposited film was less than 1 mu m.

  • 41.
    Vasiliauskas, Remigijus
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Mekys, A.
    Institute of Applied Research, Vilnius University, LT 10222, Vilnius, Lithuania.
    Malinovskis, P.
    Institute of Applied Research, Vilnius University, LT 10222, Vilnius, Lithuania.
    Juillaguer, Sandrine
    CNRS and Université Montpellier 2, Laboratoire Charles Coulomb, Montpellier, France.
    Syväjärvi, Mikael
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Storasta, J.
    Institute of Applied Research, Vilnius University, LT 10222, Vilnius, Lithuania.
    Yakimova, Risitza
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Impact of extended defects on Hall and magnetoresistivity effects in cubic silicon carbide2012Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 45, nr 22, s. 225102-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    From magnetoresistivity effect measurements the carrier mobility at room- temperature is 200 cm2/Vs in heteroepitaxially grown 3C-SiC on 6H-SiC by sublimation epitaxy. The main scattering mechanisms are found to be scattering by neutral impurities at low temperature and by phonons at higher temperature. The carrier concentration is in the range of 1016  cm-3, which corresponds to the concentration of residual doping by nitrogen acquired  from  photoluminescence  measurements.  Using  magnetoresistance  and  Hall mobility data we have created a simple model which quantifies the volume of the samples influenced by extended defects. A higher doping near extended defects is either not present in the samples or might be screened by the electrostatic field created by these defects.

  • 42.
    Vukajlovic Plestina, Jelena
    et al.
    Ecole Polytech Federal Lausanne, Switzerland.
    Derek, Vedran
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten. Rudjer Boskovic Institute, Croatia.
    Francaviglia, Luca
    Ecole Polytech Federal Lausanne, Switzerland.
    Amaduzzi, Francesca
    Ecole Polytech Federal Lausanne, Switzerland.
    Potts, Heidi
    Ecole Polytech Federal Lausanne, Switzerland.
    Ivanda, Mile
    Rudjer Boskovic Institute, Croatia.
    Fontcuberta i Morral, Anna
    Ecole Polytech Federal Lausanne, Switzerland.
    Nanoporous silicon tubes: the role of geometry in nanostructure formation and application to light emitting diodes2017Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 50, nr 26, artikkel-id 265101Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Obtaining light emission from silicon has been the holy grail of optoelectronics over the last few decades. One of the most common methods for obtaining light emission from silicon is to reduce it to a nanoscale structure, for example by producing porous silicon. Here, we present a method for the large-area fabrication of porous silicon microtubes by the stain etching of silicon micropillar arrays. We explain and model how the formation of the microtubes is influenced by the morphology of the substrate, especially the concave or convex character of the 3D features. Light emission is demonstrated at the micro- and nanoscale respectively by photo- and cathodoluminescence. Finally, we demonstrate a 0.55 cm(2) device that can work as a photodetector with 2.3% conversion efficiency under one sun illumination, and also as a broadband light emitting diode, illustrating the applicability of our results for optoelectronic applications.

  • 43.
    Yakimova, Rositsa
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Petoral, Rodrigo Jr
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Yazdi, Gholamreza
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Vahlberg, Cecilia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Lloyd Spetz, Anita
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik.
    Uvdal, Kajsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Surface functionalization and biomedical applications based on SiC2007Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 40, nr 20, s. 6435-6442Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The search for materials and systems, capable of operating long term under physiological conditions, has been a strategy for many research groups during the past years. Silicon carbide (SiC) is a material, which can meet the demands due to its high biocompatibility, high inertness to biological tissues and to aggressive environment, and the possibility to make all types of electronic devices. This paper reviews progress in biomedical and biosensor related research on SiC. For example, less biofouling and platelet aggregation when exposed to blood is taken advantage of in a variety of medical implantable materials while the robust semiconducting properties can be explored in surface functionalized bioelectronic devices. © 2007 IOP Publishing Ltd.

  • 44.
    Zhang, Hongpeng
    et al.
    Xidian Univ, Peoples R China.
    Yuan, Lei
    Xidian Univ, Peoples R China.
    Jia, Renxu
    Xidian Univ, Peoples R China.
    Tang, Xiaoyan
    Xidian Univ, Peoples R China.
    Hu, Jichao
    Xian Univ Technol, Peoples R China.
    Zhang, Yimen
    Xidian Univ, Peoples R China.
    Zhang, Yuming
    Xidian Univ, Peoples R China.
    Sun, Jianwu
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Stress-induced charge trapping and electrical properties of atomic-layer-deposited HfAlO/Ga2O3 metal-oxide-semiconductor capacitors2019Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 52, nr 21, artikkel-id 215104Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electrical properties and trapping characteristics of an atomic layer deposited Al-rich HfAlO/beta-Ga2O3 capacitor were evaluated via constant-voltage stress (CVS), capacitance-voltage (C-V), and current-voltage (I-V) measurements. The magnitude of the stress-induced charge trapping increases with increasing voltage and time. The effective charges (N-eff) including the border traps located in near-interface oxide, interface traps (D-it) of HfAlO/beta-Ga2O3 interface, and fixed charges contribute significantly to the observed charge trapping, and it is found that interface traps contribute more under a large stress bias, compared with border traps. In addition, the effective charge density is increased with stress time, implying that the contribution of negative sheet charges during the CVS process might not be negligible. Measurements of oxide permittivity (10.74), interface state density (D-it similar to 1 x 10(12) eV(-1) cm(-2)), and gate leakage current (1.18 x 10( -5) A cm(-2) at +10 V) have been extracted, suggesting the great electrical properties of Al-rich HfAlO/beta-Ga203 MOSCAP. According to the above analysis, Al-rich HfAlO is an attractive candidate for normally off Ga2O3 transistors.

    Fulltekst (pdf)
    fulltext
  • 45.
    Žukauskaitė, Agnė
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Tholander, Christopher
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Pališaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Persson, Per O. Å.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Darakchieva, Vanya
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Ben Sedrine, Nebiha
    Instituto Tecnológico e Nuclear, 2686-953 Sacavém and CFNUL, Lisbon 1649-003, Portugal.
    Tasnádi, Ferenc
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Alling, Björn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    YxAl1-xN Thin Films2012Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 45, nr 42, s. 422001-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Reactive magnetron sputtering was used to deposit YxAl1-xN thin films, 0≤x≤0.22, onto Al2O3(0001) and Si(100) substrates. X-ray diffraction and analytical electron microscopy show that the films are solid solutions. Lattice constants are increasing with Y concentration, in agreement with ab initio calculations. Spectroscopic ellipsometry measurements reveal a band gap decrease from 6.2 eV (x=0) down to 4.9 eV (x=0.22). Theoretical investigations within the special quasirandom structure approach show that the wurtzite structure has the lowest mixingenthalpy for 0≤x≤0.75.

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