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  • 251. Fu, Y.
    et al.
    Engström, O.
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Emission rates for electron tunneling from InAs quantum dots to GaAs substrate (vol 96, pg 6477, 2004)2005In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 98, no 5, p. 059901-Article in journal (Refereed)
  • 252.
    Fu, Y
    et al.
    Chalmers University of Technology.
    Willander, Magnus
    Chalmers University of Technology.
    Electron wave-packet transport through nanoscale semiconductor device in time domain2005In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 97, no 9Article in journal (Refereed)
    Abstract [en]

    Future low-power downscaled metal-oxide-semiconductor (MOS) devices are in a size regime that requires a quantum-mechanical approach. Two theoretical approaches, the steady-state single plane-wave transport model and the time-dependent wave-packet transport model, have been discussed to study the electron transport through model nanoscale potential profiles. It has been shown that the single plane-wave transport model at steady state neglects the coupling among different plane waves induced by the potential profile variation induced by the external bias. Thus, the model is only valid when the external bias is rather small. The electron wave-packet transport theory models the electrons by wave packets consisting of all available plane waves in the contact from where the electrons originate. The couplings among different plane waves are included in the temporal evolution of the time-dependent Schrodinger equation. This model is thus more proper when studying nanoscale devices at normal device working configurations. The effects of gate bias and the device geometry on the wave-packet transport are then studied by model potentials of future downscaled devices, which explains the experimentally reported conventional I-V characteristics of nanoscale MOS field-effect transistors (MOSFETs) at room temperature, while the normal MOSFET functioning is expected to be impossible by the single plane-wave transport model due to the independent tunneling effects of individual plane waves.

  • 253.
    Fu, Y
    et al.
    Chalmers University of Technology.
    Willander, Magnus
    Chalmers University of Technology.
    Jiang, J
    Chinese Academy of Sciences.
    Li, N
    Chinese Academy of Sciences.
    Lu, W
    Chinese Academy of Sciences.
    Liu, HC
    Chinese Academy of Sciences.
    Photocurrents of 14 mu m quantum-well infrared photodetectors2003In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 93, no 12, p. 9432-9436Article in journal (Refereed)
    Abstract [en]

    We study the factors that determine photogenerated carriers and response wavelengths of photocurrents of long wavelength (similar to14 mum) quantum well (QW) infrared photodetectors (QWIPs). The material structures of QWIPs are first characterized by the photoluminescence measurements (PL). By calculating the density of photogenerated carriers in the continuum above the energy barriers using the PL calibrated QWIP structures, we have demonstrated that due to the sample quality, the photocarriers can be either in miniband states (Bloch states in the multiple quantum wells), or they transport from one quantum well to the next in the form of running waves. By including possible scattering processes at the QWIP working temperature to link the theoretically calculated photocarrier density with the experimentally measured photocurrent, it is shown that the width of the photocurrent peaks of 14 mum GaAs/AlGaAs QWIPs under investigation is determined by the optical phonon emissions of photocarriers. We have further calculated the densities of photocarriers in the QWIPs reported in the literature. It is shown that the Bloch wave boundary conditions are appropriate for QWIPs with narrow QWs, whereas running wave boundary conditions are appropriate for wide QWs.

  • 254.
    Fu, Ying
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Energy band structure and spectral gain characteristics of dilute-nitride zinc blende InGaNAs quantum wells embedded in GaAs and GaNAs barriers2006In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 100, no 7Article in journal (Refereed)
    Abstract [en]

    The spectral gain characteristics of dilute-nitride zinc blende InxGa1-xNyAs1-y quantum wells embedded in GaNy1As1-y1 barriers have been investigated experimentally and theoretically. Two samples, both with the gain peak at 1300 nm, were studied for comparison. One has a high nitrogen concentration in the quantum well with the surrounding barriers being pure GaAs. The other has a lower and uniform nitrogen concentration in the quantum well and the barriers (GaNAs barriers). Measurements show the redshift of the gain peak induced by the incorporation of nitrogen and difference in the spectral gain characteristics. The energy band structures and spectral gain characteristics are analyzed theoretically using the standard eight-band k center dot p theory. It is shown that the introduction of nitrogen atoms in the GaAs barriers reduces the barrier height for the central quantum well so that the energy sublevels in the conduction band becomes condensed. The condensation of the conduction-band energy sublevels reduces the peak gain and makes the gain spectrum narrower, in agreement with measurements.

  • 255.
    Fu, Ying
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Photonic energy band structure of excitonic quantum dot dimer system2009In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 106, no 5Article in journal (Refereed)
    Abstract [en]

    We study the energy dispersion of a photonic crystal composed of two types of excitonic quantum dots (QD dimer system), type-I QDs at their ground states while type-II QDs are already excited. The excitation and de-excitation of the exciton states in the QDs by an external electromagnetic field contribute extra dielectric polarizations with respect to the background material, thus a contrast in the dielectric constant and the eventual formation of the photonic dispersion. By assuming periodic boundary conditions, it has been shown that the photonic dispersion of the QD dimer system is composed of modified but still characteristic dispersions of the two types of QDs in their separate photonic crystal formats. Starting from the transparent condition of type-II QDs, the photonic structure of the QD dimer system evolves from the one of type-I QDs to the composite dimer system. The modification due to the radiative interaction between the two types of the QDs is symmetric with respect to the change in the excitation degree of type-II QDs (increase/decrease the excitation degree from transparent status so that type-II QDs become optically gain/lossy). It is thus concluded that the transport of an external electromagnetic field is normal in the QD dimer system and achieving a lossless negative-dielectric material at a single frequency is possible by using the QD dimer system.

  • 256.
    Fu, Ying
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Lu, W
    Jiang, J
    Wang, MK
    Yang, XP
    Wu, G
    Fan, YH
    Li, YG
    Nonperturbative dynamic photon absorption of quantum wells2006In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 99, no 10Article in journal (Refereed)
    Abstract [en]

    Optical photoresponse of quantum wells in the nonperturbative regime has been studied by high-power and ultrafast-oscillating free-electron laser (FEL) experiments, which revealed a profound deviation of the nonlinear power from conventional perturbative multiple photon absorption processes. By combining the experimental and theoretical works we have shown that the nonperturbative solution of the time-dependent Schrodinger equation is essential to understand the experimental observations. Optical transitions of electrons are dynamic. One photon is absorbed or emitted when an electron transits from one electron state to the other. The rates of absorption and emission are proportional to the time interval in the femtosecond time scale. In the picosecond time scale, multiphoton processes emerge. The strong and fast-oscillating FEL source intensifies the dynamic photon absorption and emission processes in the quantum wells, resulting in a much enhanced nonlinearity in the photoresponse spectrum.

  • 257. Fu, Yu
    et al.
    Barsukov, I.
    Meckenstock, R.
    Lindner, J.
    Zhai, Y.
    Hjörvarsson, Björgvin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Farle, M.
    Uniaxial anisotropy and its manipulation in amorphous Co68Fe24Zr8 thin films (invited)2014In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 115, no 17, p. 172605-Article in journal (Refereed)
    Abstract [en]

    We have proven that the growth of Co68Fe24Zr8 layers under external field yields a uniaxial anisotropy, defined by the direction of the field. No magnetic coupling is present between Co68Fe24Zr8 layers when separated by a 3 nm of Al70Zr30. The anisotropy axis can therefore be manipulated at will and the direction can be tailored, layer by layer in multilayers, by the choice of the direction of the applied field during growth. The g-factor (2.13) and the anisotropy constant, obtained from ferromagnetic resonance, support the existence of short-range order. The relation between the temperature dependences of magnetic anisotropy and magnetization are partially captured by Callen-Callen power law. (C) 2014 AIP Publishing LLC.

  • 258. Fu, Yu
    et al.
    Barsukov, I.
    Raanaei, Hossein
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Spasova, M.
    Lindner, J.
    Meckenstock, R.
    Farle, M.
    Hjörvarsson, Björgvin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Tailored magnetic anisotropy in an amorphous trilayer2011In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 109, no 11, p. 113908-Article in journal (Refereed)
    Abstract [en]

    An amorphous Co68Fe24Zr8(3 nm)/Al70Zr30(3 nm)/Co68Fe24Zr8(3 nm) trilayer system has been investigated using in-plane and out-of-plane angular dependent ferromagnetic resonance at different frequencies. The in-plane magnetic anisotropy is uniaxial, retaining its value of (2.9 +/- 0.1) x 10(3) J/m(3) for each magnetic layer, whereas its direction was tailored independently in an arbitrary manner by applying an external magnetic field during the film deposition. The perpendicular anisotropy constant, supposed to reflect the interface quality, is nearly identical for both layers. Furthermore, the magnetic layers act independently upon each other due to the absence of interlayer coupling.

  • 259.
    Gabrysch, Markus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Majdi, Saman
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Twitchen, Daniel
    Element Six Ltd, Ascot Berkshire, UK.
    Isberg, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Electron and hole drift velocity in chemical vapor deposition diamond2011In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 109, no 6, p. 063719-Article in journal (Refereed)
    Abstract [en]

    The time-of-flight technique has been used to measure the drift velocities for electrons and holes in high-purity single-crystalline CVD diamond. Measurements were made in the temperature interval 83 ≤ T ≤ 460 K and for electric fields between 90 and 4 × 103 V/cm, applied in the <100> crystallographic direction. The study includes low-field drift mobilities and is performed in the low-injection regime to perturb the applied electric field only minimally.

  • 260.
    Gabrysch, Markus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Marklund, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Hajdu, Janos
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Twitchen, D. J.
    Element Six Ltd, Ascot SL5 8BP, Berks, England.
    Rudati, J.
    Stanford Linear Accelerator Ctr, PULSE Ctr, Menlo Pk, CA 94025 USA.
    Lindenberg, A. M.
    Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA; PULSE Center, Stanford Linear Accelerator Center, Menlo Park, California 94025, USA.
    Caleman, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Falcone, R. W.
    Department of Physics, University of California, Berkeley, California 94720, USA.
    Tschentscher, T.
    Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany.
    Moffat, K.
    Consortium for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, USA.
    Bucksbaum, P. H.
    PULSE Center, Stanford Linear Accelerator Center, Menlo Park, California 94025, USA.
    Als-Nielsen, J.
    Niels Bohr Institute, Copenhagen University, 2100 Copenhagen Ø, Denmark.
    Nelson, A. J.
    Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
    Siddons, D. P.
    National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973, USA.
    Emma, P. J.
    Stanford Linear Accelerator Ctr, PULSE Ctr, Menlo Pk, CA 94025 USA.
    Krejcik, P.
    Stanford Linear Accelerator Ctr, PULSE Ctr, Menlo Pk, CA 94025 USA.
    Schlarb, H.
    Stanford Linear Accelerator Ctr, PULSE Ctr, Menlo Pk, CA 94025 USA.
    Arthur, J.
    Stanford Linear Accelerator Ctr, PULSE Ctr, Menlo Pk, CA 94025 USA.
    Brennan, S.
    Stanford Linear Accelerator Ctr, PULSE Ctr, Menlo Pk, CA 94025 USA.
    Hastings, J.
    Stanford Linear Accelerator Ctr, PULSE Ctr, Menlo Pk, CA 94025 USA.
    Isberg, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Formation of secondary electron cascades in single-crystalline plasma-deposited diamond upon exposure to femtosecond x-ray pulses2008In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 103, no 6, article id 064909Article in journal (Refereed)
    Abstract [en]

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

  • 261. Gago, R
    et al.
    Jimenez, I
    Agullo-Rueda, F
    Albella, JM
    Czigany, Z
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Transition from amorphous boron carbide to hexagonal boron carbon nitride thin films induced by nitrogen ion assistance2002In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 92, no 9, p. 5177-5182Article in journal (Refereed)
    Abstract [en]

    Boron carbon nitride films (BCN) were grown by B4C evaporation under concurrent N-2 ion beam assistance. The films were characterized by x-ray absorption near-edge spectroscopy, infrared and Raman spectroscopies, and high-resolution transmission electron microscopy. The bonding structure and film composition correlate with the momentum transfer per incoming atom during deposition. As the momentum transfer is increased, the film structure evolves from an amorphous boron carbide network towards a hexagonal ternary compound (h-BCN) with standing basal planes. The growth of h-BCN takes place for momentum transfer in the window between 80 and 250 (eVxamu)(1/2). The characteristic vibrational features of the h-BCN compounds have also been studied. Finally, the solubility limit of carbon in the hexagonal BN structure, under the working conditions of this article, is found to be similar to15 at. %. (C) 2002 American Institute of Physics.

  • 262. Galeckas, A.
    et al.
    Linnros, Jan
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Breitholtz, B.
    Bleichner, H.
    Application of optical emission microscopy for reliability studies in 4H-SiC p(+)/n(-)/n(+) diodes2001In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 90, no 2, p. 980-984Article in journal (Refereed)
    Abstract [en]

    An optical emission microscopy technique with spatial and spectral resolution capabilities is applied for stability studies of 4H-SiC material properties. From the example of a 4H-SiC p(+)/n(-)/n(+) diode imaged at different stages of electrical overstress the mechanism of degrading performance is directly unveiled. We correlate this phenomenon with irreversible structural changes within the active region created by a nonuniform heating related stress. The stress-generated features are interpreted as multiple stacking faults spreading throughout the whole base region and nucleated in the vicinity of built-in defects and process-induced structural deficiencies.

  • 263.
    Gallo, Katia
    et al.
    Optoelectronics Research Centre, University of Southampton.
    Gawith, C.B.E.
    Wellington, I.T.
    Mailis, Sakellaris
    Eason, Robert
    Smith, Peter
    Richardson, David
    Kostritskii, Sergey
    Ultraviolet writing of channel waveguides in proton-exchanged LiNbO32007In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 101, no 1, p. 014110-Article in journal (Refereed)
    Abstract [en]

    We report on a direct ultraviolet (UV) writing method for the fabrication of channel waveguides at 1.55 mu m in LiNbO3 through UV irradiation of surface and buried planar waveguides made by annealed proton exchange and reverse proton exchange. A systematic study of the guidance properties as a function of the UV writing conditions is presented.

  • 264. Ganguli, Nirmal
    et al.
    Dasgupta, Indra
    Sanyal, Biplab
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Electronic structure and magnetism of transition metal doped Zn12O12 clusters: Role of defects2010In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 108, no 12, p. 123911-Article in journal (Refereed)
    Abstract [en]

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

  • 265.
    Gao, Feng
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Cai, C.
    Nanjing University, Peoples R China.
    Wang, Y.
    Nanjing University, Peoples R China.
    Dong, S.
    Nanjing University, Peoples R China.
    Qiu, X. Y.
    Nanjing University, Peoples R China.
    Yuan, G. L.
    Nanjing University, Peoples R China.
    Liu, Z. G.
    Nanjing University, Peoples R China.
    Liu, J. -M.
    Nanjing University, Peoples R China.
    Preparation of la-doped BiFeO3 thin films with Fe2+ ions on Si substrates2006In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 99, no 9, p. 094105-Article in journal (Refereed)
    Abstract [en]

    La-doped BiFeO3 thin films with Fe2+ ions have been prepared on Pt/TiO2/SiO2/Si substrates by pulsed laser deposition in order to enhance the ferroelectric and magnetic properties. The targets for the film deposition were synthesized using a rapid liquid phase sintering technique to ensure the low leakage. The dielectric properties at room temperature and above were investigated. It was observed that the La doping greatly enhances the ferroelectric polarization at room temperature by modifying the film structure from rhombohedral to monoclinic. The saturation magnetization was enhanced about two times due to the Fe2+ ions in the thin films. (C) 2006 American Institute of Physics.

  • 266.
    Gelzinyte, Kristina
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Vilnius State Univ, Inst Appl Res, Lithuania.
    Ivanov, Ruslan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Marcinkevicius, Saulius
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Zhao, Y.
    Becerra, D. L.
    Nakamura, S.
    DenBaars, S. P.
    Speck, J. S.
    High spatial uniformity of photoluminescence spectra in semipolar (20(2)over-bar1) plane InGaN/GaN quantum wells2015In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 117, no 2, p. 023111-Article in journal (Refereed)
    Abstract [en]

    Scanning near-field optical spectroscopy was applied to study spatial variations of emission spectra at room temperature in semipolar (20 (2) over bar1) InxGa(1-x)N/GaN single quantum wells (QWs) for 0:11 <= x <= 0:36. Photoluminescence (PL) was found to be highly uniform, with peak wavelength deviations and peak intensity deviations divided by average values in the range of 6-12 meV and 0.03-0.07, respectively. Near-field maps of PL parameters showed large, similar to 5 to 10 mu m size areas of similar values, as opposed to 100 nm scale variations, often reported for InGaN QWs. The near-field PL spectra were found to broaden with increasing InN molar fraction. In the low In content QWs, the broadening is primarily determined by the random cation distribution, while for larger InN molar fractions 10 nm scale localization sites with increasingly deeper band potentials are suggested as the linewidth broadening cause.

  • 267.
    Ghavanini, Farzan
    et al.
    Department of Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Göteborg, Sweden.
    Jackman, Henrik
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Lundgren, Per
    Department of Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Göteborg, Sweden.
    Svensson, Krister
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Enoksson, Peter
    Department of Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Göteborg, Sweden.
    Direct measurement of bending stiffness and estimation of Young’s modulus of vertically aligned carbon nanofibers2013In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 113, no 19Article in journal (Refereed)
    Abstract [en]

    We have measured the bending stiffness of as-grown vertically aligned carbon nanofibers using atomic force microscopy inside a scanning electron microscope. We show that the assumption of a uniform internal structure is inadequate in describing nanofibers mechanical properties and that a dual phase model is needed. We present a model in which different Young’s moduli are assigned to the inner graphitic core and the outer amorphous carbon shell and show that it provides a better fit to the measurements. We obtain values of 11±8 GPa and 63±14 GPa for the Young’s modulus of the inner core and the outer shell, respectively.

  • 268. Girt, Erol
    et al.
    Huttema, W.
    Mryasov, O. N.
    Montoya, E.
    Kardasz, B.
    Eyrich, C.
    Heinrich, B.
    Dobin, A. Yu.
    Karis, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    A method for measuring exchange stiffness in ferromagnetic films2011In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 109, no 7, p. 07B765-Article in journal (Refereed)
    Abstract [en]

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

  • 269. GISLASON, HP
    et al.
    YANG, BH
    PETURSSON, J
    LINNARSSON, M
    KTH, School of Information and Communication Technology (ICT).
    RADIATIVE RECOMBINATION IN N-TYPE AND P-TYPE GAAS COMPENSATED WITH LI1993In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 74, p. 7275-7287Article in journal (Refereed)
    Abstract [en]

    We report fundamental changes of the radiative recombination in a wide range of n-type and p-type GaAs after diffusion with the group-I element Li. These optical properties are found to be a bulk property and closely related to the electrical conductivity of the samples. In the Li-doped samples the radiative recombination is characterized by emissions with excitation-dependent peak positions which shift to lower energies with increasing degree of compensation and concentration of Li. These properties are shown to be in qualitative agreement with fluctuations of the electrostatic potential in strongly compensated systems. For Li-diffusion temperatures above 700-800-degrees-C semi-insulating conditions with electrical resistivity exceeding 10(7) OMEGA cm are obtained for all conducting starting materials. In this heavy Li-doping regime, the simple model of fluctuating potentials is shown to be inadequate for explaining the. experimental observations unless the number of charged impurities is reduced through complexing with Li. For samples doped with low concentrations of Li, on the other hand, the photoluminescence properties are found to be characteristic of impurity-related emissions.

  • 270.
    Gogova, Daniela
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Kasic, A.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Larsson, Henrik
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Hemmingsson, Carl
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Monemar, Bo
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Tuomisto, F.
    Laboratory of Physics, Helsinki University of Technology, Finland .
    Saarinen, K.
    Laboratory of Physics, Helsinki University of Technology, Finland .
    Dobos, L.
    Research Institute for Technical Physics and Materials Science of the Hungarian Academy of Science, Hungary .
    Pécz, B.
    Research Institute for Technical Physics and Materials Science of the Hungarian Academy of Science, Hungary .
    Gibart, P.
    LUMILOG, 2720, Chemin de Saint Bernard, France .
    Beaumont, B.
    LUMILOG, 2720, Chemin de Saint Bernard, France .
    Strain-free bulk-like GaN grown by hydride-vapor-phase-epitaxy on two-step epitaxial lateral overgrown GaN template2004In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 96, no 1, p. 799-806Article in journal (Refereed)
    Abstract [en]

    Crack-free bulk-like GaN with high crystalline quality has been obtained by hydride-vapor-phase-epitaxy (HVPE) growth on a two-step epitaxial lateral overgrown GaN template on sapphire. During the cooling down stage, the as-grown 270-μm-thick GaN layer was self-separated from the sapphire substrate. Plan-view transmission electron microscopy images show the dislocation density of the free-standing HVPE-GaN to be ∼2.5×107 cm−2 on the Ga-polar face. A low Ga vacancy related defect concentration of about 8×1015 cm−3 is extracted from positron annihilation spectroscopy data. The residual stress and the crystalline quality of the material are studied by two complementary techniques. Low-temperature photoluminescence spectra show the main neutral donor bound exciton line to be composed of a doublet structure at 3.4715 (3.4712) eV and 3.4721 (3.4718) eV for the Ga- (N-) polar face with the higher-energy component dominating. These line positions suggest virtually strain-free material on both surfaces with high crystalline quality as indicated by the small full width at half maximum values of the donor bound exciton lines. The E1(TO) phonon mode position measured at 558.52 cm−1 (Ga face) by infrared spectroscopic ellipsometry confirms the small residual stress in the material, which is hence well suited to act as a lattice-constant and thermal-expansion-coefficient matched substrate for further homoepitaxy, as needed for high-quality III-nitride device applications. © 2004 American Institute of Physics.

  • 271.
    Golod, Taras
    et al.
    Stockholm University, Faculty of Science, Department of Physics.
    Rydh, Andreas
    Stockholm University, Faculty of Science, Department of Physics.
    Krasnov, Vladimir M.
    Stockholm University, Faculty of Science, Department of Physics.
    Anomalous Hall effect in NiPt thin films2011In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 110, no 3, p. 033909-Article in journal (Refereed)
    Abstract [en]

    We study Hall effect in sputtered NixPt1-x thin films with different Ni concentrations. Temperature, magnetic field andangular dependencies are analyzed and the phase diagram of NiPt thin films is obtained. It is found that films with sub-critical Ni concentration exhibit cluster-glass behavior at low temperatures with a perpendicular magnetic anisotropy below the freezing temperature. Films with super-critical Ni concentration are ferromagnetic with parallel anisotropy. At the critical concentration the state of the film is strongly frustrated. Such films demonstrate canted magnetization with the easy axis rotating as a function of temperature. The magnetism appears via consecutive paramagnetic - cluster glass - ferromagnetic transitions, rather than a single second-order phase transition. But most remarkably, the extraordinary Hall effect changes sign at the critical concentration. We suggest that this is associated with a reconstruction of the electronic structure of the alloy at the normal metal - ferromagnet quantum phase transition.

  • 272. Goncharov, Alexander F.
    et al.
    Wong, Michael
    Dalton, D. Allen
    Ojwang, J. G. O.
    Struzhkin, Viktor V.
    Konopkova, Zuzana
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Thermal conductivity of argon at high pressures and high temperatures2012In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 111, no 11, p. 112609-Article in journal (Refereed)
    Abstract [en]

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

  • 273.
    Gonschorek, M.
    et al.
    Institute of Quantum Electronics and Photonics, Ecole Polytechnique F´d´rale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
    Carlin, J.-F.
    Institute of Quantum Electronics and Photonics, Ecole Polytechnique F´d´rale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
    Feltin, E.
    Institute of Quantum Electronics and Photonics, Ecole Polytechnique F´d´rale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
    Py, M.A.
    Institute of Quantum Electronics and Photonics, Ecole Polytechnique F´d´rale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
    Grandjean, N.
    Institute of Quantum Electronics and Photonics, Ecole Polytechnique F´d´rale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
    Darakchieva, Vanya
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Lorenz, M.
    Institut für Experimentelle Physik II, Fakultät für Physik und Geowissenschaften, Universität Leipzig, Linnstraße 3-5, 04103 Leipzig, Germany.
    Ramm, G.
    Institut für Experimentelle Physik II, Fakultät für Physik und Geowissenschaften, Universität Leipzig, Linnstraße 3-5, 04103 Leipzig, Germany.
    Two-dimensional electron gas density in Al1-x InMx N/AlN/GaN heterostructures (0.03=x=0.23)2008In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 103, no 9, p. 093714-Article in journal (Refereed)
    Abstract [en]

    Compared to the AlGaN alloy, which can only be grown under tensile strain on GaN, the AlInN alloy is predicted by Vegard's law to be lattice-matched (LM) on fully relaxed GaN templates for an indium content of ~17.5%, i.e., it can be grown either tensely or compressively on GaN. The effect of strain on the polarization induced sheet charge density at the Al1-x Inx N/AlN/GaN heterointerfaces is carefully investigated for 6 and 14 nm thick AlInN barriers including a 1 nm thick AlN interlayer. The barrier indium content ranges at 0.03=x=0.23 for 6 nm thick barriers and 0.07=x=0.21 for 14 nm thick barriers. It is found that the two-dimensional electron gas (2DEG) density varies between (3.5±0.1) × 1013 cm-2 and (2.2±0.1) × 1013 cm-2 for 14 nm thick barriers. Finally, a 2DEG density up to (1.7±0.1) × 1013 cm-2 is obtained for a nearly LM AlInN barrier with ~14.5% indium on GaN as thin as 6 nm. © 2008 American Institute of Physics.

  • 274. Gouvea, Paula M. P.
    et al.
    Jang, Hoon
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Carvalho, Isabel C. S.
    Cremona, M.
    Braga, Arthur M. B.
    Fokine, Michael
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Internal specular reflection from nanoparticle layers on the end face of optical fibers2011In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 109, no 10, p. 103114-Article in journal (Refereed)
    Abstract [en]

    Metal nanoparticles deposited on a dielectric substrate exhibit an absorption peak due to localized surface plasmon resonance (LSPR). Changes in the refractive index of the surrounding medium cause the LSPR band to shift in wavelength. In this paper, gold nanoparticles were placed on the end face of an optical fiber spliced to a reflection setup. As expected in reflection geometries, the back-reflected signal exhibits a dip at wavelengths in the LSPR band when the fiber tip is surrounded by ambient air (n = 1). However, as the refractive index of the surrounding medium is increased, there is a gradual inversion from a dip (n = 1.0) to a peak (n = 2.0). To explain these results, a model based on absorption and interference between the specular reflections from the fiber/nanoparticle and nanoparticle/ambient interfaces is proposed, showing that our reflection configuration can be used in sensing applications.

  • 275.
    GRANBERG, P
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    NORDBLAD, P
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    SVEDLINDH, P
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    LUNDGREN, L
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    STUBI, R
    KENNING, GG
    LESLIEPELECKY, DL
    BASS, J
    COWEN, J
    DIMENSIONALITY CROSSOVER IN CUMN SPIN-GLASS FILMS1990In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 67, p. 5252-5254Article in journal (Refereed)
  • 276.
    Granlund, T
    et al.
    Linkoping Univ, Dept Phys & Measurement Technol, Appl Phys Lab, S-58183 Linkoping, Sweden Chalmers Univ Technol, Dept Organ Chem & Polymer Technol, S-41296 Gothenburg, Sweden.
    Pettersson, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Andersson, MR
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Luminescence probing of crystallization in a polymer film2000In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 87, no 12, p. 8549-8556Article in journal (Refereed)
    Abstract [en]

    We report studies of a thin film multilayer stack including a highly emissive substituted polythiophene, poly[3-(2,5-dioctylphenyl)thiophene]. Analysis of the photoluminescence spectra revealed an inhomogeneous polymer film. X-ray diffraction studies attribute the existence of an inhomogeneous film as originating from crystallization of the polymer. We used the interference effect of light to detect the region of crystallization in the film. Photoluminescence and absorption were redshifted upon crystallization and displayed an enhanced vibronic structure. Comparison between calculated and measured photoluminescence shows that the crystallization starts from the top of the film and not from the supporting substrate. (C) 2000 American Institute of Physics. [S0021- 8979(00)08112-3].

  • 277.
    Granlund, T
    et al.
    Linkoping Univ, Dept Phys & Measurement Technol, Appl Phys Lab, S-58183 Linkoping, Sweden.
    Pettersson, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Determination of the emission zone in a single-layer polymer light-emitting diode through optical measurements2001In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 89, no 11, p. 5897-5902Article in journal (Refereed)
    Abstract [en]

    We study the emission zone in a single-layer polymer light-emitting diode. The emission zone is found by studying the angular distribution of the electroluminescence. The emission is modeled by accounting for optical interference. We account for birefringence of the anode layer in our model. The active polymer was, however, found to be isotropic. The anode consists of a single-layer of the conducting polymer complex poly(3,4-ethylenedioxythiophene) and poly(styrene sulfonate) (PEDOT-PSS), with enhanced conductivity. As a cathode we use plain aluminum. By using only PEDOT-PSS we avoid having a thin metal layer or indium-tin-oxide as the anode in the path of the escaping light. The active material is a substituted polythiophene with excellent film forming properties. A comparison between the experimental and calculated angular distribution of light emission from a single-layered polymer light-emitting diode was shown to be in good agreement for the spectral region studied. By assuming a distribution of the emission zone, we deduce the position as well as the width of the zone. (C) 2001 American Institute of Physics.

  • 278.
    Greczynski, G
    et al.
    Linkoping Univ, Dept Phys, S-58183 Linkoping, Sweden ACREO AB, Interconnect & Packaging, S-60221 Norrkoping, Sweden.
    Kugler, T
    Salaneck, William R
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry .
    Energy level alignment in organic-based three-layer structures studied by photoelectron spectroscopy2000In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 88, no 12, p. 7187-7191Article in journal (Refereed)
    Abstract [en]

    The alignment of energy band edges at interfaces in three-layer structures, important in polymer-based electroluminescent devices, have been studied using photoelectron spectroscopy. Careful choice of the materials allows investigation of the role of the substrate work function. These results are in agreement with the energy level diagram commonly assumed for the metal/polymer/metal structure, with the potential drop over the polymer layer being equal to the difference between the work functions of the metal contacts. Direct indication of the alignment of the electrochemical potential across the three-layer structure has been observed by photoelectron spectroscopy. (C) 2000 American Institute of Physics. [S0021-8979(00)06801-3].

  • 279.
    Greczynski, G.
    et al.
    Linkoping Univ, Dept Phys IFM, Thin Film Phys Div, SE-58183 Linkoping, Sweden.;Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Mraz, S.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Hans, M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lu, J.
    Linkoping Univ, Dept Phys IFM, Thin Film Phys Div, SE-58183 Linkoping, Sweden..
    Hultman, L.
    Linkoping Univ, Dept Phys IFM, Thin Film Phys Div, SE-58183 Linkoping, Sweden..
    Schneider, J. M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Unprecedented Al supersaturation in single-phase rock salt structure VAlN films by Al+ subplantation2017In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 121, no 17, article id 171907Article in journal (Refereed)
    Abstract [en]

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

  • 280.
    Greczynski, Grzegorz
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Rhein Westfal TH Aachen, Germany.
    Mraz, S.
    Rhein Westfal TH Aachen, Germany.
    Hans, M.
    Rhein Westfal TH Aachen, Germany.
    Primetzhofer, D.
    Uppsala University, Sweden.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Schneider, J. M.
    Rhein Westfal TH Aachen, Germany.
    Unprecedented Al supersaturation in single-phase rock salt structure VAlN films by Al+ subplantation2017In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 121, no 17, article id 171907Article in journal (Refereed)
    Abstract [en]

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

  • 281.
    Greczynski, Grzegorz
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Rhein Westfal TH Aachen, Germany.
    Mraz, S.
    Rhein Westfal TH Aachen, Germany.
    Ruess, H.
    Rhein Westfal TH Aachen, Germany.
    Hans, M.
    Rhein Westfal TH Aachen, Germany.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Schneider, J. M.
    Rhein Westfal TH Aachen, Germany.
    Extended metastable Al solubility in cubic VAlN by metal-ion bombardment during pulsed magnetron sputtering: film stress vs subplantation2017In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 122, no 2, article id 025304Article in journal (Refereed)
    Abstract [en]

    Dynamic ion-recoil mixing of near-film-surface atomic layers is commonly used to increase the metastable solubility limit x(max) in otherwise immiscible thin film systems during physical vapor deposition. Recently, Al subplantation achieved by irradiating the film growth surface with Al+ metal-ion flux was shown to result in an unprecedented x(max) for VAlN, far above values obtained with gas ion irradiation. However, it is reasonable to assume that ion irradiation necessary for subplantation also leads to a compressive stress sigma buildup. In order to separate the effects of Al+ bombardment on sigma and x(max), and realize low-stress high-x(max) nitride alloys, we grow metastable cubic V1-xAlxN (0.17 amp;lt;= x amp;lt;= 0.74) films using reactive magnetron sputtering under different ion irradiation conditions. Al and V targets are operated in Ar/N-2 discharges employing (i) conventional DC (Ar+, N-2(+)), (ii) hybrid High-power pulsed magnetron sputtering (HIPIMS)/DC processing with one type of metal ion present (Al+ or V+/V2+), and (iii) HIPIMS with concurrent Al+ and V+/V2+ fluxes. Comparison to the ab initio calculated Al solubility limit reveals that x(max) = 0.55 achieved with V+/V2+ irradiation is entirely accountable for by stress. In contrast, Al+ fluxes provide a substantial increase in x(max) to 0.63, which is 12% higher than that expected based on the stress-induced increase in metastable solubility. Correlative stress and atom probe tomography data confirm that the metastable Al solubility enhancement is enabled by Al+ subplantation. The here proposed processing strategy allows for growth of single-phase cubic nitride alloys with significantly increased Al concentrations embodying tremendous promise for substantial improvements in high temperature oxidation resistance and mitigates the risk of stress-induced adhesive or cohesive coating failure. Published by AIP Publishing.

  • 282.
    Grishin, A.
    et al.
    Kungliga tekniska högskolan, KTH.
    Niska, John
    Luleå tekniska universitet.
    Loberg, Bengt
    Weber, Hans
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Straightened voltage effect in high-Tc superconductors1994In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 76, no 10, p. 6947-6949Article in journal (Refereed)
    Abstract [en]

    A new effect called ``ac-current straightening'' has been observed in ceramic (Bi,Pb)-2223 slabs carrying ac current Idc+Iac cos(ωt). The current-voltage (I-V) characteristics of the ceramic were measured at 77 K at frequencies ranging from 50 to 20 000 Hz. A spectrum analyzer showed a series of high harmonics in the voltage signal as well as a constant voltage drop. The full set of experimental data has been explained theoretically using the Bean-Kim critical state model with a magnetic field dependent critical current jc(H)=jc(0)/(1+H/H0). A low transport ac current gives a voltage linearly proportional to the frequency and quadratically proportional to the ac-current amplitude Iac. It consists of odd harmonics only. If a bias dc current is switched on, then even harmonics and a dc-voltage drop appear. Their amplitudes are proportional to the small parameter Iac/cH0 and depend on the Idc/Iac ratio.

  • 283.
    Grishin, Alexander
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Khartsev, Sergey
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Dzibrou, Dzmitry
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Enhanced photoluminescence in [Er2O3/TiO2]m photonic crystals2009In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 105, no 11, p. 113122-Article in journal (Refereed)
    Abstract [en]

    We survey optical properties of [Er2O3/TiO 2]6/Er2O32/[TiO 2/Er2O3]6 photonic crystals (PCs) pulsed laser deposited on to the glass substrates. The dispersion relations of refractive indexes and extinction coefficients of the constituent materials were obtained from the comparison of experimental and simulated transmission spectra of single layer Er2O3 and TiO2 reference films. Based on these data several PCs have been designed and grown to match stop band and cavity mode resonance at wavelengths close to the 523 nm Er 3+-ion Fraunhofer 4S3/2 absorption line. Precise control of chemical composition and uniform multilayer thickness enable achievement of superior optical performance of sintered PCs. Obtained dispersion relations were combined with the 2×2 transfer matrix formalism to compute PC transmittance that appeared to be in a good agreement with the experimental spectra. Pumping PCs with 514 nm light source we observed a strong photoluminescence (PL) at 1535 nm. In PC specially designed for the resonance wavelength λres =514 nm, C-band PL intensity experiences fivefold enhancement compared to a single layer Er2 O3 film of equivalent thickness.

  • 284. Grivickas, P.
    et al.
    Grivickas, V.
    Linnros, Jan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Galeckas, A.
    Fundamental band edge absorption in nominally undoped and doped 4H-SiC2007In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 101, no 12Article in journal (Refereed)
    Abstract [en]

    Fundamental band edge absorption is investigated in nominally undoped (n < 1014 cm(-3)) and heavily doped (n similar to 8 x 10(18) cm(-3)) 4H-SiC by a spectroscopy technique based on spatially and time-resolved free-carrier absorption. The spectra are extracted over a wide absorption range (0.02-500 cm(-1)) at temperatures from 75 to 450 K. The experimental results are supported by an indirect transition theory with a unique set of dominating momentum-conserving phonons, showing good correlation with earlier findings of differential absorption measurements at 2 K. Exciton binding energy of 30 +/- 10 meV is derived from fitting the data at 75 K. The detected polarization anisotropy of absorption with respect to c axis is shown to be consistent with the selection rules for the corresponding phonon branches. An analytical model related to constant degree of involved phonons describes well the obtained energy gap variation with temperature. Finally, doping induced band gap narrowing is characterized above the impurity-Mott transition and compared with theoretical calculations in the random phase approximation. The shape of the fundamental absorption edge at high carrier concentrations is discussed in terms of excitonic enhancement above the Mott transition, as recently detected in Si.

  • 285.
    Gudmundsson, Jon Tomas
    et al.
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics. University of Iceland, Iceland.
    Snorrason, David I.
    University of Iceland.
    On electron heating in a low pressure capacitively coupled oxygen discharge2017In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 122, no 19, article id 193302Article in journal (Refereed)
  • 286.
    Gudmundsson, Jon Tomas
    et al.
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics. University of Iceland, Iceland.
    Ventejou, Bruno
    The pressure dependence of the discharge properties in a capacitively coupled oxygen discharge2015In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 118, no 15, article id 153302Article in journal (Refereed)
    Abstract [en]

    We use the one-dimensional object-oriented particle-in-cell Monte Carlo collision code oopd1 to explore the evolution of the charged particle density profiles, electron heating mechanism, and the electron energy probability function (EEPF) in a capacitively coupled oxygen discharge with pressure in the pressure range of 10-500 mTorr. We find that at higher pressure (50-500 mTorr) the electron heating occurs mainly in the sheath region, and detachment by the metastable singlet molecule O-2(a(1)Delta(g)) has a significant influence on the electron heating process. At a low pressure (10 mTorr), Ohmic heating in the bulk plasma (the electronegative core) dominates, and detachment by O-2(a(1)Delta(g)) has only a small influence on the heating process. Thus at low pressure, the EEPF is convex and as the pressure is increased the number of low energy electrons increases and the number of higher energy electrons (> 10 eV) decreases, and the EEPF develops a concave shape or becomes bi-Maxwellian.

  • 287.
    Gunnarsson, Rickard
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    Pilch, Iris
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Boyd, Robert
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    Brenning, Nils
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering. KTH Royal Institute Technology, Sweden.
    Helmersson, Ulf
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    The influence of pressure and gas flow on size and morphology of titanium oxide nanoparticles synthesized by hollow cathode sputtering2016In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 120, no 4, p. 044308-Article in journal (Refereed)
    Abstract [en]

    Titanium oxide nanoparticles have been synthesized via sputtering of a hollow cathode in an argon atmosphere. The influence of pressure and gas flow has been studied. Changing the pressure affects the nanoparticle size, increasing approximately proportional to the pressure squared. The influence of gas flow is dependent on the pressure. In the low pressure regime (107 amp;lt;= p amp;lt;= 143 Pa), the nanoparticle size decreases with increasing gas flow; however, at high pressure (p = 215 Pa), the trend is reversed. For low pressures and high gas flows, it was necessary to add oxygen for the particles to nucleate. There is also a morphological transition of the nanoparticle shape that is dependent on the pressure. Shapes such as faceted, cubic, and cauliflower can be obtained. Published by AIP Publishing.

  • 288. Gunnarsson, Rickard
    et al.
    Pilch, Iris
    Boyd, Robert D.
    Brenning, Nils
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Helmersson, Ulf
    The influence of pressure and gas flow on size and morphology of titanium oxide nanoparticles synthesized by hollow cathode sputtering2016In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 120, no 4, article id 044308Article in journal (Refereed)
    Abstract [en]

    Titanium oxide nanoparticles have been synthesized via sputtering of a hollow cathode in an argon atmosphere. The influence of pressure and gas flow has been studied. Changing the pressure affects the nanoparticle size, increasing approximately proportional to the pressure squared. The influence of gas flow is dependent on the pressure. In the low pressure regime (107 <= p <= 143 Pa), the nanoparticle size decreases with increasing gas flow; however, at high pressure (p = 215 Pa), the trend is reversed. For low pressures and high gas flows, it was necessary to add oxygen for the particles to nucleate. There is also a morphological transition of the nanoparticle shape that is dependent on the pressure. Shapes such as faceted, cubic, and cauliflower can be obtained. Published by AIP Publishing.

  • 289.
    Gunnarsson, Robert
    et al.
    Chalmers tekniska högskola, Institutionen för mikroteknologi och nanovetenskap.
    Hanson, Maj
    Chalmers tekniska högskola, Institutionen för tillämpad fysik.
    Dubourdieu, Catherine
    Laboratiore des Matériaux et du Génie Physique, CNRS, St. Martin d'Hères.
    Stoner-Wohlfarth model applied to bicrystal magnetoresistance hysteresis2004In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 96, no 1, p. 482-485Article in journal (Refereed)
    Abstract [en]

    We calculate numerically the magnetization direction as function of magnetic field in the Stoner–Wohlfarth theory and are able to reproduce the shape of the low-field magnetoresistance hysteresis observed in manganite grain boundary junctions. Moreover, we show that it is necessary to include biaxial magnetocrystalline anisotropy to fully describe the grain boundary magnetoresistance in La0.7Sr0.3MnO3/SrTiO3 bicrystal tunnel junctions.

  • 290.
    Gupta, Amita
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Cao, Hongtao
    Parekh, Kinnari
    Rao, K. Venkat
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Raju, A. R.
    Waghmare, Umesh V.
    Room temperature ferromagnetism in transition metal (V, Cr, Ti) doped In(2)O(3)2007In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 101, no 9, p. 09N513-Article in journal (Refereed)
    Abstract [en]

    Indium oxide is chosen as the host material for doping Ti, V, and Cr transition metal ions. Theoretical calculations based on density functional theory within a local spin density approximation show that V-V separation of 5.6 A is more stable with a strong ferromagnetic coupling. Our calculations clearly predict that substitution of vanadium for indium should yield ferromagnetism in In(2)O(3). Experimentally, (In(0.95)TM(0.05))O(3) (TM=Ti,V,Cr) were prepared using sol-gel as well as solid state reaction methods. Superconducting quantum interference device magnetization measurements as a function of field and temperature clearly showed that the V and Cr doped samples are ferromagnetic with Curie temperature well above room temperature. Thin films deposited by pulsed laser ablation using these materials on sapphire substrates exhibit a preferred 222 orientation normal to the plane of the film. The magnetic moment for (In(0.95)V(0.05))O(3) film deposited in 0.1 mbar oxygen pressure was estimated to be 1.7 mu(B)/V and is comparable to the theoretical value of 2 mu(B)/V.

  • 291.
    Gustafsson, Göran
    Luleå tekniska universitet.
    Experiments on shock-wave focusing in an elliptical cavity1987In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 61, no 11, p. 5193-5195Article in journal (Refereed)
    Abstract [en]

    Experimental work on reflection and focusing of weak cylindrical shock waves in a liquid-filled elliptical cavity is presented. The shocks are generated at one focus of the cavity by electrical discharges, and converge at the other focus after reflection in the cavity wall. High-speed photographs of the resulting wave system, which appears to be considerably more complex than the corresponding one in air, are shown and discussed. The results are of interest in the design of a transient water-jet generator, which utilizes the energy in the converging shock wave to produce a fast liquid jet.

  • 292.
    Gåård, Anders
    et al.
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Hirvonen Grytzelius, Joakim
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Krakhmalev, Pavel
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Zhang, Hanmin
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Bergström, Jens
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering. Karlstad University, Faculty of Technology and Science, Materials Science.
    Experimental study of the relationship between temperature and adhesive forces for low-alloyed steel, stainless steel and titanium using atomic force microscopy in ultra-high vacuum2008In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, ISSN 0021-8979, Vol. 103, no 12, article id 124301Article in journal (Refereed)
  • 293. Haddad, Noël
    et al.
    Garcia-Caurel, Enric
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Barsoum, Michel W
    Hug, Gilles
    Dielectric properties of Ti2AlC and Ti2AlN MAX phases: The conductivity anisotropy2008In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 104, no 2Article in journal (Refereed)
    Abstract [en]

    The optical properties of Ti2AlN and Ti2AlC were determined in the 2-80 eV energy range by electron energy loss spectroscopy and in the visible-ultraviolet range, from 1.6 to 5.5 eV, by spectroscopic ellipsometry. Both experimental techniques are angular resolved and in very good agreement over their overlapping energy range. We observe a dependence of the dielectric function as a function of the crystallographic orientation of the crystals. In particular, we notice a shift of the energy position of the plasmon absorption of Ti2AlC with respect to Ti2AlN. Moreover, a drastic change is also observed in the shape of the dielectric function as a function of the composition (or valence electron concentration). The dielectric functions are fitted to an empirical semiclassic Drude-Lorentz model to obtain physical parameters such as the relaxation times. These microscopic parameters are then used in a macroscopic model to yield the transport properties such as the static conductivity as function of the crystal orientation. Ti 2AlN is found to be a better conductor than Ti2AlC in all orientations, which is consistent with experimental measurements. A comparison of the electrical and optical properties of these two compounds is made in terms of different electronic properties and interband-intraband transitions deduced from our model. © 2008 American Institute of Physics.

  • 294. Hagman, H.
    et al.
    Sjolund, P.
    Petra, S. J. H.
    Nylen, M.
    Kastberg, A.
    Ellmann, H.
    Stockholm University, Faculty of Science, Department of Physics.
    Jersblad, J.
    Stockholm University, Faculty of Science, Department of Physics.
    Assessment of a time-of-flight detection technique for measuring small velocities of cold atoms2009In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 105, no 8, p. 83109-Article in journal (Refereed)
    Abstract [en]

    A low noise time-of-flight detection system for laser cooled atoms has been constructed and incrementally optimized. Here, a thorough description of the construction is presented along with an analysis of the capabilities of the system. The quality of the detection (the resolution, the reproducibility, the sensitivity, etc.) is crucial for, e.g., the ability to see details in the velocity distribution profile, which is of interest for fundamental studies of statistical physics and of the laser cooling processes, and for detection of small initial velocities of an atomic cloud, important, e.g., when studying small drifts induced by Brownian motors and ratchets. We estimate the signal-to-noise ratio of our signal to be better than 1000:1 for a typical single shot, and we discuss the effect of the initial atomic cloud size, the probe size, and the effects of the wave packet spread during the fall time on the measured quantities. We show that the shape of the velocity distribution is well conserved during the mapping done in the detection, i.e., in the convolution with the probe beam, and that velocities as small as a few percent of the single photon recoil velocity can be resolved.

  • 295.
    Hagman, Henning
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Sjölund, Peder
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Petra, Stefan J. H.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Nylén, Mats
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Kastberg, Anders
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Ellmann, Harald
    Department of Physics, Stockholm University, AlbaNova University Center, SE-106 91 Stockholm, Sweden.
    Jersblad, Johan
    Department of Physics, Stockholm University, AlbaNova University Center, SE-106 91 Stockholm, Sweden.
    Assessment of a time-of-flight detection technique for measuring small velocities of cold atoms2009In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 105, no 8, p. 083109-Article in journal (Refereed)
    Abstract [en]

    A low noise time-of-flight detection system for laser cooled atoms has been constructed and incrementally optimized. Here, a thorough description of the construction is presented along with an analysis of the capabilities of the system. The quality of the detection (the resolution, the reproducibility, the sensitivity, etc.) is crucial for, e.g., the ability to see details in the velocity distribution profile, which is of interest for fundamental studies of statistical physics and of the laser cooling processes, and for detection of small initial velocities of an atomic cloud, important, e.g., when studying small drifts induced by Brownian motors and ratchets. We estimate the signal-to-noise ratio of our signal to be better than 1000:1 for a typical single shot, and we discuss the effect of the initial atomic cloud size, the probe size, and the effects of the wave packet spread during the fall time on the measured quantities. We show that the shape of the velocity distribution is well conserved during the mapping done in the detection, i.e., in the convolution with the probe beam, and that velocities as small as a few percent of the single photon recoil velocity can be resolved.

  • 296. Hahn, Giso
    et al.
    Zechner, C.
    Rinio, Markus
    Fath, Peter
    Willeke, G.
    Bucher, E.
    Enhanced Carrier Collection observed in Mechanically Structured Silicon with Small Diffusion Length1999In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 86, no 12, p. 43-47 mflArticle in journal (Refereed)
    Abstract [en]

    The diffusion length of minority charge carriers in the silicon bulk Ldiffis an important characteristicof optoelectronic devices fabricated from low cost silicon wafers. In this study computer simulationshave been carried out to calculate the beneficial effects of a macroscopic surface texturization on thecharge carrier generation and the collection probability. Textured solar cells should be able tocollect charge carriers more effectively resulting in an increased current due to the special emittergeometry resulting from the texture, decreased reflection losses, and the inclined penetration of thelight. In order to prove this expected behavior, deeply V-textured solar cells have been processedand characterized on low cost silicon reaching an Ldiffof about 25 mm. Spatially resolved highresolution measurements of the internal quantum efficiency exhibit a strongly increased signal in thetexture tips which is the first experimental proof of the increased charge carrier collectionprobability of deeply textured solar cells. This effect can further be seen in cross sectional electronbeam induced current measurements and the mechanical texture results in an overall gain in shortcircuit current density of about 11% and in efficiency of about 8% relatively.

  • 297.
    Hai, Ling
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Svensson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Isberg, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Leijon, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. Univ Southampton, Energy & Climate Change Div, Fac Engn & Environm, Southampton, Hants, England.
    Modelling a point absorbing wave energy converter by the equivalent electric circuit theory: A feasibility study2015In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 117, article id 164901Article in journal (Refereed)
    Abstract [en]

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

  • 298. Haidar, M.
    et al.
    Ranjbar, M.
    Balinsky, M.
    Dumas, R. K.
    Khartsev, Sergiy
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Åkerman, Johan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF. University of Gothenburg, Sweden.
    Thickness- and temperature-dependent magnetodynamic properties of yttrium iron garnet thin films2015In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 117, no 17, article id 17D119Article in journal (Refereed)
    Abstract [en]

    The magnetodynamical properties of nanometer-thick yttrium iron garnet films are studied using ferromagnetic resonance as a function of temperature. The films were grown on gadolinium gallium garnet substrates by pulsed laser deposition. First, we found that the damping coefficient increases as the temperature increases for different film thicknesses. Second, we found two different dependencies of the damping on film thickness: at room temperature, the damping coefficient increases as the film thickness decreases, while at T = 8 K, we find the damping to depend only weakly on the thickness. We attribute this behavior to an enhancement of the relaxation of the magnetization by impurities or defects at the surfaces.

  • 299. Hallstedt, J.
    et al.
    Blomqvist, M.
    Persson, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Radamson, H. H.
    The effect of carbon and germanium on phase transformation of nickel on Si1-x-yGexCy epitaxial layers2004In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 95, no 5, p. 2397-2402Article in journal (Refereed)
    Abstract [en]

    The influence of germanium and carbon on the phase formation, strain relaxation and the occurrence of agglomeration of the Si1-x-yGe xCy epitaxial layers in Ni/SiGe(C) system were investigated. The defects formed by the reaction of Ni on SiGe(C) layers were investigated using cross-sectional transmission electron microscopy (XTEM). It was observed that NisiGe layers were crystalline and with strong growth orientation in the direction, but the thermal stability was decreased with increasing Ge amount due to agglomeration. It was also observed that at the interface of NiSiGe/SiGeC carbon was accumulated at low-temperature annealing which retarded the phase transformation and agglomeration of Ni/SiGeC systems.

  • 300. Hallén, A
    et al.
    Paska, Z
    Rosling, M
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Sundqvist, BUR
    Svensson, BG
    Tirén, J
    Deep level transient spectroscopy analysis of fast ion tracks in silicon1990In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 67, no 3, p. 1266-1271Article in journal (Refereed)
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