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  • 1.
    Backenhamn Ohlsson, Margareta
    University of Gävle, Faculty of Engineering and Sustainable Development.
    Fysik genom musik: en introduktion av fysikaliska fenomen i förskolans vardag med stöd av ett arbetsmaterial och en lärarhandledning2013Independent thesis Basic level (professional degree), 210 HE creditsStudent thesis
  • 2.
    Bennett, J. M.
    et al.
    Physics Division, Michelson Laboratory, Naval Air Warfare Center, China Lake, CA, United States.
    Rönnow, Daniel
    Acreo AB, Kista, Sweden.
    Test of Opticlean strip coating material for removing surface contamination2000In: Applied Optics, ISSN 0003-6935, E-ISSN 1539-4522, Vol. 39, no 16, p. 2737-2739Article in journal (Refereed)
    Abstract [en]

    The strip coating material, Opticlean, which has been reformulated, has been shown to remove 1-5-mu m-diameter particles as well as contamination remaining from previous drag wipe cleaning on a used silicon wafer. In addition, no residue that produced scattering was found on a fresh silicon wafer when Opticlean was applied and then stripped off. The total integrated scattering technique used for the measurements could measure scattering levels of He-Ne laser light as low as a few ppm (parts in 106), corresponding to a surface roughness of <1 Angstrom rms.

  • 3. Order onlineBuy this publication >>
    Björling, Mikael
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Kemi för de yngre åren2016In: Ämnesdidaktiska utmaningar inom matematik, naturvetenskap och teknik / [ed] Mikael Björling, Gävle: Gävle University Press , 2016, 1, p. 109-132Chapter in book (Other academic)
    Abstract [sv]

    Detta är bakgrunden till att små barn är fascinerande av att leka Titt-ut,men som alla föräldrar vet så försvinner den lekens lockelse när barnet blir äldre. Barn utvecklas snabbt i de yngre åren, vilket skapar både möjligheter och begränsningar för hur lärande i naturvetenskap och kemi uppstår i förskolan och grundskolan. Det finns många skäl till att kemirelaterade aktiviteter bör introduceras i de yngre åren och i det här kapitlet diskuteras några av dessa skäl ur ett kemididaktiskt perspektiv. Kapitlet är uppbyggt kring några av de betydande framsteg som gjorts i den utvecklingspsykologiska forskningen under de senaste tjugo åren (Gärdenfors, 2006). Idag vet vi ganska mycket om hur våra hjärnor fungerar och utvecklas. Insprängt i denna beskrivning kommer jag att reflektera kring hur detta skulle kunna påverka valet av innehåll när det gäller naturvetenskapligt lärande för yngre barn. På slutet sammanfattar jag tankarna om innehåll med ett speciellt fokus på kemi.

  • 4.
    Bustad, Johnny
    University of Gävle, Department of Mathematics, Natural and Computer Sciences. Natur.
    Computational studies of core level XPS satellites in transition metal systems: Department of Quantum Chemistry, Uppsala University1995Doctoral thesis, monograph (Other scientific)
    Abstract [en]

    Upon core ionization of a free molecule or a molecule adsorbed on a metal surface, higher binding energy satellites are observed, so called "shake-up" satellites, which can be viewed as valence excitations simultaneously to the creation of the core hole. In this thesis, theoretical studies of such core level XPS satellites in transition metal systems are presented, as well as cluster calculations of XES spectra, using the quantum mechanical INDO method. The main motivation of these studies is to get a more detailed understanding of the bonding between the adsorbed molecules and the metal and the screening process accompanying the creation of the core hole. This interest is motivated by fundamental questions about the adsorbate-substrate interaction as well as technical applications, such as catalysis.

    It has been found that many aspects of extended adsorbate systems, where CO is coordinated to metal atoms, can be modelled by transition metal carbonyls such as Mo(CO)6, Cr(CO)6 and Ni(CO)4. The bonding between the core ionized CO group and the transition metal, consists of an interaction between, on the one hand, the sigma lone pair of the ligand and, on the other hand, the metal d-orbitals and the CO antibonding pi-star orbital of the CO-group, i.e. a sigma donation from the ligand and pi donation from the metal. It is the changes in this bonding which are responsible for the dominant features of the shake-up spectra in the studied model molecules. The main conclusion of the three abovementioned case studies is that new excitations involving charge transfer from the metal to the ionized ligand occur with significant probability in the metal carbonyls, in addition to the internal excitations present also in free CO.

    In extending the model towards larger systems, calculations of CO/Ni(100), N2//Ni(100), CO/Cu(100) and benzene/Cu(100) were undertaken, where the metal surface was modelled by clusters of 1-12 metal atoms. Many of the features from the metal carbonyls are found also in these systems. The most important added feature is the presence of high-intensity metal-metal excitations, which mainly affect the shape of the main line.

    Ground state cluster calculations were performed to explain the XES spectra of CO adsorbed on Ni(100) and Cu(100) surfaces. It was found that the calculations reproduce the important characteristics of the experimental spectra, and were used as a support for the assignments of the involved states.

  • 5.
    Cardona, M.
    et al.
    Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
    Rönnow, Daniel
    Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
    Santos, P. V.
    Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
    Ellipsometric investigations of piezo-optical effects1998In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 313-314, p. 10-17Article in journal (Refereed)
    Abstract [en]

    An introduction to the stress-induced birefringence of solids, with emphasis on cubic and amorphous materials, is given. Most available experimental data have been obtained in the frequency region below the electronic absorption edge: the corresponding coefficients of the stress-optical tensor are then real. Above the edge (and also in the IR region of the Reststrahlen) they become complex. Ellipsometry is an excellent tool for the investigation of complex stress-optical functions. It also yields the hydrostatic pressure induced changes in the dielectric functions. Data obtained recently for diamond and zincblende-type crystals and their theoretical interpretation are discussed.

  • 6.
    Carreras Bertran, Antoni
    University of Gävle, Faculty of Engineering and Sustainable Development.
    Energy System and Economic Analysis of District coolingin the city hall of Gävle2013Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • 7. Chen, R.
    et al.
    Wang, M.
    Wang, S.
    Liang, Hao
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Hu, X.
    Sun, X.
    Zhu, J.
    Ma, L.
    Jiang, M.
    Hu, J.
    Li, J.
    A low cost surface plasmon resonance biosensor using a laser line generator2015In: Optics Communications, ISSN 0030-4018, E-ISSN 1873-0310, Vol. 349, p. 83-88Article in journal (Refereed)
    Abstract [en]

    Due to the instrument designed by using a common surface plasmon resonance biosensor is extremely expensive, we established a portable and cost-effective surface plasmon resonance biosensing system. It is mainly composed of laser line generator, P-polarizer, customized prism, microfluidic cell, and line Charge Coupled Device (CCD) array. Microprocessor PIC24FJ128GA006 with embedded A/D converter, communication interface circuit and photoelectric signal amplifier circuit are used to obtain the weak signals from the biosensing system. Moreover, the line CCD module is checked and optimized on the number of pixels, pixels dimension, output amplifier and the timing diagram. The micro-flow cell is made of stainless steel with a high thermal conductivity, and the microprocessor based Proportional-Integral-Derivative (PID) temperature-controlled algorithm was designed to keep the constant temperature (25 °C) of the sample solutions. Correspondingly, the data algorithms designed especially to this biosensing system including amplitude-limiting filtering algorithm, data normalization and curve plotting were programmed efficiently. To validate the performance of the biosensor, ethanol solution samples at the concentrations of 5%, 7.5%, 10%, 12.5% and 15% in volumetric fractions were used, respectively. The fitting equation ΔRU=-752987.265+570237.348×RI with the R-Square of 0.97344 was established by delta response units (ΔRUs) to refractive indexes (RI). The maximum relative standard deviation (RSD) of 4.8% was obtained. 

  • 8.
    Granqvist, C. G.
    et al.
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Azens, A.
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Kullman, L.
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Rönnow, Daniel
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Progress in Smart Windows Research: Improved Electrochromic W Oxide Films and Transparent Ti-Ce Oxide Counter Electrodes1996In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 8, no 1-4, p. 97-106Article in journal (Refereed)
    Abstract [en]

    We review recent work on sputter deposited W-oxide-based films. Improved electrochemical durability was obtained by electron bombardment during deposition, and enhanced coloration/bleaching dynamics was obtained by fluorination. Spectrally resolved scattering measurements indicated that haze levels ≪ 1 % could be reached. Oblique angle deposition could yield angular selectivity. New results are given for sputtered Ti-Ce oxide films, showing their capacity as counter electrodes in transparent electrochromic devices.

  • 9.
    Granqvist, C.-G.
    et al.
    The Ångström Laboratory, Deptartment of Material Science, Uppsala University, Uppsala, Sweden.
    Azens, A.
    The Ångström Laboratory, Deptartment of Material Science, Uppsala University, Uppsala, Sweden.
    Hjelm, A.
    The Ångström Laboratory, Deptartment of Material Science, Uppsala University, Uppsala, Sweden.
    Kullman, L.
    The Ångström Laboratory, Deptartment of Material Science, Uppsala University, Uppsala, Sweden.
    Niklasson, G. A.
    The Ångström Laboratory, Deptartment of Material Science, Uppsala University, Uppsala, Sweden.
    Rönnow, Daniel
    The Ångström Laboratory, Deptartment of Material Science, Uppsala University, Uppsala, Sweden.
    Strömme, M.
    The Ångström Laboratory, Deptartment of Material Science, Uppsala University, Uppsala, Sweden.
    Veszelei, M.
    The Ångström Laboratory, Deptartment of Material Science, Uppsala University, Uppsala, Sweden.
    Vaivars, G.
    Institute of Solid State Physics, University of Latvia, Riga, Latvia.
    Recent advances in electrochromics for smart windows applications1998Conference paper (Other academic)
  • 10.
    Iggland, Anders
    et al.
    University of Gävle, Department of Business Administration and Economics.
    Johansson, Dan
    University of Gävle, Department of Business Administration and Economics.
    En studie om Varumärken i media - Hur ska GävleTidningar förhålla sig till Arbetarbladet och GefleDagblad?2007Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [en]

    The purpose with the study is to examine the complex problem of brands, in a competition - and cooperation situation.

  • 11.
    Ivarsson, Jenny
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Physics.
    Att lära sig ett modelltänkande: exemplet magnetism2012In: I mötet mellan vetenskap och lärande: 13 högskolepedagogiska utmaningar / [ed] Göran Fransson & Helena Hammarström, Gävle: Gävle University Press , 2012, p. 217-234Chapter in book (Other academic)
  • 12. Order onlineBuy this publication >>
    Ivarsson, Jenny
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Physics.
    Einstein för alla2016In: Ämnesdidaktiska utmaningar inom matematik, naturvetenskap och teknik / [ed] Mikael Björling, Gävle: Gävle University Press , 2016, 1, p. 75-88Chapter in book (Other academic)
    Abstract [sv]

    Varför är det så få elever som väljer att läsa fysik nuförtiden? Många citat tillskrivna Albert Einstein vittnar om en glädje att lära sig förstå naturen. Ändå är det idag många som upplever att fysik i skolan är tråkigt (Lindahl, 2003). Måste det verkligen vara så? Tänk om skolan kunde fånga något av det som lockade Einstein.

  • 13. Order onlineBuy this publication >>
    Ivarsson, Jenny
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Physics.
    Renässans för filosofisk fysik2016In: Ämnesdidaktiska utmaningar inom matematik, naturvetenskap och teknik / [ed] Mikael Björling, Gävle: Gävle University Press , 2016, 1, p. 89-108Chapter in book (Other academic)
    Abstract [sv]

    Fysik kan ge omskakande insikter om vår värld på ett filosofiskt plan. Ofta förmedlas fysik i undervisningen som en odiskutabel och färdig produkt, trots att vi fortfarande inte vet särskilt mycket om hur världen fungerar egentligen. Kanske skulle det inspirera flera att läsa fysik om undervisningen även tog upp frågor som inte har färdiga svar. Går det att väcka liv i den filosofiska diskussionen som fördes mellan Albert Einstein och Niels Bohr om tolkningen av kvantfysik?

  • 14.
    Kullman, L.
    et al.
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Rönnow, Daniel
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Granqvist, C. G.
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Elastic Light Scattering and Electrochemical Durability of Electrochromic Tungsten-oxide-based Films1996In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 288, no 1-2, p. 330-333Article in journal (Refereed)
    Abstract [en]

    Electrochromic W-oxide-based films were produced by reactive d.c. magnetron sputtering. Fluorination and substrate bias were used to modify the film properties. Spectral measurements of the total and diffuse light scattering showed that the diffuse component remained at much less than 1% in the visible, irrespective of electrochemical degradation, which is low enough for smart windows applications.

  • 15.
    Lastras-Martínez, L. F.
    et al.
    Max-Planck-Institut Festkorperforschung, Stuttgart, Germany; Instituto de Investigación en Comunicación Optica, Universidad Autonóma de San Luis Potosí, San Luis Potosí, Mexico.
    Rönnow, Daniel
    Max-Planck-Institut Festkorperforschung, Stuttgart, Germany.
    Santos, P. V.
    Max-Planck-Institut Festkorperforschung, Stuttgart, Germany; Paul-Drude-Institut für Festkörperelektronik, Berlin, Germany.
    Cardona, M.
    Max-Planck-Institut Festkorperforschung, Stuttgart, Germany.
    Eberl, K.
    Max-Planck-Institut Festkorperforschung, Stuttgart, Germany.
    Optical anisotropy of (001)-GaAs surface quantum wells2001In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 64, no 24, p. 2453031-2453038, article id 245303Article in journal (Refereed)
    Abstract [en]

    We report a reflectance difference spectroscopy (RDS) study of the optical anisotropy of GaAs:(001) surface quantum wells consisting of a thin GaAs layer (3-30 nm thick) embedded between an arsenic reconstructed surface and an AlAs barrier. The RDS spectra display anisotropic contributions from the free surface and from the GaAs/AlAs interface. By comparing RDS spectra for the c(4×4) and (2×4) surface reconstructions, we separate these two contributions, and demonstrate that the anisotropy around the E1 and E11 transitions comprises a component originating from modifications of bulk states near the surface. The latter is attributed to anisotropic strains induced by the surface reconstruction. The experimental data are well described by a model for the RDS response of the multilayer structures, which also takes into account the blue energy shifts and the changes in oscillator strength of the E1 and E11 transitions induced by quantum-well confinement.

  • 16.
    Lastras-Martí­nez, L. F.
    et al.
    Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
    Santos, P. V.
    Paul-Drude-Institut für Festkörperelektronik, Berlin, Germany.
    Rönnow, Daniel
    Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
    Cardona, M.
    Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
    Specht, P.
    Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
    Eberl, K.
    Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
    Reflectance difference spectroscopy of GaAs asymmetric surface quantum wells above the fundamental gap1998In: Physica status solidi. A, Applied research, ISSN 0031-8965, E-ISSN 1521-396X, Vol. 170, no 2, p. 317-321Article in journal (Refereed)
    Abstract [en]

    We report Reflectance Difference (RD) measurement on (001) GaAs surface quantum wells (QW) under Ultra High Vacuum (UHV) conditions from 1.7 to 5.0eV. The QW is embedded between an arsenic-rich reconstructed GaAs surface and an AlAs barrier. The samples, grown by MBE with a protective arsenic cap layer, were heated to 320 and 430°C to desorb the As layer and form c(4 x 4) and (2 x 4) surface reconstructions, respectively. By modifying the surface reconstructure, we are able to separate the contributions to the optical anisotropy from the surface region (mainly associated with the As dimers) from those originating below the surface.

  • 17.
    Lindstrom, T
    et al.
    Department of Materials Science, Ångström Laboratory, Uppspla University, Uppsala, Sweden.
    Rönnow, Daniel
    ACREO AB, Kista, Sweden.
    Total integrated scattering from transparent substrates in the infrared region: validity of scalar theory2000In: Optical Engineering: The Journal of SPIE, ISSN 0091-3286, E-ISSN 1560-2303, Vol. 39, no 2, p. 478-487Article in journal (Refereed)
    Abstract [en]

    Integrated light scattering, from thin, transparent silicon wafers with different front and backside surface roughness is investigated. The measurements are made at near normal incidence in the IR wavelength region 5 to 20 μm using an integrating sphere. A method to separate the scattering contribution from each interface for measurements on transparent samples is introduced. Scalar scattering theory is used to calculate the effective root mean square roughness from reflectance and transmittance measurements, and these values are compared to profilometer data, correcting for the different bandwidth limits. Scattering measurements are performed with both the rough and the smooth surface of the wafer oriented toward the light source, which results in additional knowledge. The maximum ratio between the root mean square roughness and the wavelength of the light, to be used in scalar theory, is found to be considerably higher for the transmittance case than for the reflectance case. In agreement with theory, the calculated root mean square roughness is found to be proportional to the refractive index of incident medium in reflectance, and to the difference in refractive indices of incident and refracting medium for the transmittance case.

  • 18.
    Lindström, T.
    et al.
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Kullman, L.
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Rönnow, Daniel
    Max-Planck-Institut für Festkörperforschung, Stuttgart ,Germany.
    Ribbing, C. G.
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Granqvist, C. G.
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Electrochromic control of thin film light scattering1997In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 81, no 3, p. 1464-69Article in journal (Refereed)
    Abstract [en]

    Total and diffuse reflectance spectra were measured on Al surfaces covered with electrochromic W oxide films in colored and bleached states. Vector perturbation theory was used for analyzing the spectra. The diffuse reflectance appeared to originate from correlated (uncorrelated) interface roughness when the W oxide film was fully colored (bleached). Assuming partially correlated interfaces led to agreement between experimental and calculated spectra. The use of an electrochromic film appears a promising method to control the relative contributions of the interfaces to the resulting scattering.

  • 19.
    Madfors, Ingela
    University of Gävle, Faculty of Education and Business Studies.
    Backward time travel and its relevance for theological study: An explorative literature study based on physics, philosophy, counterfactual thinking and theology2011Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This paper explores the possibility and relevance of theological study of backward time travel and its consequences. An examination of current research on backward time travel reveals a number of interdisciplinary topics which are not handled within physics. Some of these topics, mainly concerning free will and determination, are of interest to philosophers, whereas topics such as meaning and responsibility are left aside.   In theology, there is a general dismissal of the idea of backward time travel. This study claims that this negative stance may be the result of taking science and its methods too seriously. The result of the study is that the interdisciplinary questions connected to backward time travel makes the subject very relevant for theological reflection. Thought experiments on backward time travel can provide valuable insights on how we deal with our lives, our world, time, and God today.  

  • 20.
    Medvedik, M. Y.
    et al.
    Department of mathematics and supercomputing, Penza State University, Penza, Russia.
    Smirnov, Yu. G.
    Department of mathematics and supercomputing, Penza State University, Penza, Russia.
    Smolkin, Eugene Yu.
    University of Gävle, Faculty of Engineering and Sustainable Development.
    Tsupak, Aleksei A.
    Department of mathematics and supercomputing, Penza State University, Penza, Russia.
    Electromagnetic wave diffraction by a system of non-intersecting obstacles of various dimensions2015In: Proceedings of the 2015 International Conference on Electromagnetics in Advanced Applications: ICEAA 2015, 2015, p. 1568-1571Conference paper (Refereed)
    Abstract [en]

    The vector problem of time-harmonic electromagnetic wave diffraction by a system of non-intersecting solid inhomogeneous bodies, infinitely thin perfectly conducting screens and wire antennas is considered. The original boundary value problem for Maxwell’s equations is reduced to a system of integro-differential equations over the volume domains, the screen surfaces and antennas. To solve the integral equations approximately, the Bubnov-Galerkin method is applied; basis functions on the body, the screens and antennas are introduced as well as formulas for matrix elements in the Galerkin method. To solve the problem of diffraction by obstacles of complex shape, the subhierarchical approach is applied. © 2015 IEEE.

  • 21.
    Mirsakiyeva, Amina
    et al.
    Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, Kista, Sweden.
    Hugosson, Håkan W.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Physics.
    Linares, Mathieu
    Department Theoretical Chemistry and Biology, School of Biotechnology, KTH Royal Institute of Technology, Stockholm, Sweden; 4Swedish e-Science Research Center (SeRC), KTH Royal Institute of Technology, Stockholm, Sweden.
    Delin, Anna
    Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, Kista, Sweden; Swedish e-Science Research Center (SeRC), KTH Royal Institute of Technology, Stockholm, Sweden; Department of Physics and Astronomy, Materials Theory Division, Uppsala University, Uppsala, Sweden.
    Temperature dependence of band gaps and conformational disorder in PEDOT and its selenium and tellurium derivatives: Density functional calculations2017In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 147, no 13, article id 134906Article in journal (Refereed)
    Abstract [en]

    The conducting polymer poly(3,4-ethylenedioxythiophene), or PEDOT, is an attractive material for flexible electronics. We present combined molecular dynamics and quantum chemical calculations, based on density functional theory, of EDOT oligomers and isoelectronic selenium and tellurium derivatives (EDOS and EDOTe) to address the effect of temperature on the geometrical and electronic properties of these systems. With finite size scaling, we also extrapolate our results to the infinite polymers, i.e., PEDOT, PEDOS, and PEDOTe. Our computations indicate that the most favourable oligomer conformations at finite temperature are conformations around the flat trans-conformation and a non-flat conformation around 45° from the cis-conformation. Also, the dihedral stiffness increases with the atomic number of the heteroatom. We find excellent agreement with experimentally measured gaps for PEDOT and PEDOS. For PEDOT, the gap does not increase with temperature, whereas this is the case for its derivatives. The conformational disorder and the choice of the basis set both significantly affect the calculated gaps.

  • 22. Order onlineBuy this publication >>
    Nordlander, Edvard
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Grenholm, Jan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Teknik i skolan – en utmaning för samhället2016In: Ämnesdidaktiska utmaningar inom matematik, naturvetenskap och teknik / [ed] Mikael Björling, Gävle: Gävle University Press , 2016, 1, p. 133-151Chapter in book (Other academic)
    Abstract [sv]

    Varför är teknikyrket sällan något som ungdomar vill satsa på? Tror de att den teknik som de gärna använder – mobiltelefoner, datorer, spelkonsoler, surfplattor m.m. – utvecklas av sig själva så att man inte behöverbry sig om att bidra till detta? Kan man verkligen livnära sig på ”självförverkligande”, som tycks ha varit ledordet för tonåringar under alltför lång tid? De svenska industriföretagen som representeras av organisationen Teknikföretagen har reagerat och likaså fackföreningen Sveriges Ingenjörer. Teknikföretagen har å sin sida sedan länge alarmerat om bristerna i teknikundervisning i grundskolan och dess konsekvenser i två rapporter (Teknikföretagen, 2006, 2013) och Sveriges Ingenjörer konstaterade redan 2007 i ett pressmeddelande att ”bristen på kvalificerad arbetskraft har redan börjat visat sig och om inget görs kommer det år 2020 att fattas 50 000 ingenjörer” (Sveriges Ingenjörer, 2007). Denna siffra motsvarar ungefär 25 % av de ingenjörer, civilingenjörer, tekniker och arkitekter som Statistiska centralbyrån, SCB, redovisade i Sverige år 2006. Det är väl inte säkert att det behövs lika många ingenjörer 2020 som då, men man måste förmoda att Sverige även i framtiden har en industri som kräver kvalificerad teknisk personal. Hur skall vi annars bibehålla vårt välstånd i landet?

    I denna artikel beskrivs hur teknikundervisningen i den svenska grundskolan skall gå tillväga utifrån kursplanetexten, men frågan är om lärarna besitter kompetens i tillräcklig mån för att genomföra kursplanensintentioner. I artikeln diskuteras även möjligheten, eller svårigheten, till framtida lärarförsörjning genom att ta exempel från lärarutbildningen vid Högskolan i Gävle.

  • 23.
    Nostell, P
    et al.
    Department of Materials Science, Uppsala University, Uppsala, Sweden.
    Roos, A.
    Department of Materials Science, Uppsala University, Uppsala, Sweden.
    Rönnow, Daniel
    Max Planck Institut für Festkörperforschung, Stuttgart, Germany.
    Single-beam integrating sphere spectrophotometer for reflectance and transmittance measurements versus angle of incidence in the solar wavelength range on diffuse and specular samples1999In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 70, no 5, p. 2481-2494Article in journal (Other academic)
    Abstract [en]

    A multipurpose instrument for the measurement of reflectance and transmittance versus angle of incidence for both specular and diffuse samples in the solar wavelength range has been constructed and evaluated. The instrument operates in the single-beam mode and uses a common light source for three experimental setups. Two integrating spheres, 20 cm in diameter, are used for diffuse transmittance and reflectance measurements. The transmittance sphere can be turned around an axis through the sample to vary the angle of incidence. The reflectance sphere uses a center mounted sample and a special feature is the position of the detector, which is mounted on the sample holder at the center of the sphere. This way the detector always sees the same part of the sphere wall and no light can reach the detector directly from the sample. The third setup is an absolute instrument for specular samples. It uses a small averaging sphere as a detector. The detector is mounted on an arm which rotates around the center of the sample, and it can thus pick up both the reflected and transmitted beams including all multiply reflected components. The averaging sphere detector is insensitive to small side shifts of the detected beams and no multiple reflections between detector and optical system occur. In this report a number of calibration procedures are presented for the three experimental setups and models for the calculation of correct transmittance and reflectance values from measured data are presented. It is shown that for integrating sphere measurements, the geometry of the sphere and the diffusivity of the sample as well as the sphere wall reflectance and port losses are important factors that influence the result. For the center mounted configuration these factors are particularly important and special emphasis is given to the evaluation of the reflectance sphere model. All three instrument setups are calibrated using certified reference materials and nonscattering mirrors and substrates. The results are also compared to the results of a double-beam Beckman integrating sphere for near normal angles of incidence and Fresnel calculations. The results in this article show that good agreement is obtained between results from the different instruments if, and only if, proper evaluation procedures are applied to the measured signals.

  • 24.
    Prytz, Kjell
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    Analysis of the QCD Evolution in the Pomeron and a Search for Gluon Recombination2002Report (Other academic)
  • 25.
    Prytz, Kjell
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    Analysis of the QCD evolution in the pomeron and a search for gluon recombination2002In: Journal of Physics G: Nuclear and Particle Physics, ISSN 0954-3899, E-ISSN 1361-6471, Vol. 29, no 2, p. 285-291Article in journal (Refereed)
    Abstract [en]

    The pomeron structure function is-extracted from the HI data and is subject to a leading-order QCD analysis. We compare the results obtained from the DGLAP equations with and without corrected for gluon recombination. Both cases give good fits to data but different results for the gluon distribution.

  • 26.
    Prytz, Kjell
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Physics.
    Electrodynamics: the field-free approach: Electrostatics, magnetism, induction, relativity and field theory2015 (ed. 1)Book (Refereed)
    Abstract [en]

    This book is intended as an undergraduate textbook in electrodynamics at basic or advanced level. The objective is to attain a general understanding of the electrodynamic theory and its basic experiments and phenomena in order to form a foundation for further studies in the engineering sciences as well as in modern quantum physics.

    The outline of the book is obtained from the following principles:

    •         Base the theory on the concept of force and mutual interaction

    •         Connect the theory to experiments and observations accessible to the student

    •         Treat the electric, magnetic and inductive phenomena cohesively with respect to force, energy, dipoles and material

    •         Present electrodynamics using the same principles as in the preceding mechanics course

    •         Aim at explaining that theory of relativity is based on the magnetic effect

    •         Introduce field theory after the basic phenomena have been explored in terms of force

    Although electrodynamics is described in this book from its 1st principles, prior knowledge of about one semester of university studies in mathematics and physics is required, including vector algebra, integral and differential calculus as well as a course in mechanics, treating Newton’s laws and the energy principle.

    The target groups are physics and engineering students, as well as professionals in the field, such as high school teachers and employees in the telecom industry. Chemistry and computer science students may also benefit from the book.

  • 27.
    Prytz, Kjell
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    Electrolocation of the Weak Electric Fish2004Report (Other academic)
  • 28.
    Prytz, Kjell
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Physics.
    Elektrodynamik i nytt ljus: elektrostatik, magnetism, induktion och relativitetsteori2013 (ed. 1)Book (Refereed)
    Abstract [sv]

    Det är kanske inte helt enkelt att ge en allmänt accepterad definition av ämnet fysik. Både uppslagsböcker och fysiker ger skiftande svar på frågan. Min egen uppfattning är att fysik handlar om och utgår ifrån begreppet kra  vilket tillsammans med begreppet energi bildar dess kärna. Särskilt vill jag framhålla den definition som anges av Bonniers svenska ordbok: Fysik är "vetenskapen om naturkrafterna och energin i dess olika former". Min strävan är att låta denna definition löpa som en röd tråd i undervisningen och i denna bok.

    Innehåll

    Vi lägger därför största vikt på kraftbegreppet och dess konsekvens: växelverkningen. I första kapitlet (kapitel 2) fokuserar vi på de olika slag av kraftverkan som förekommer mellan elektriska laddningar vilka direkt kan relateras till deras rörelse, dvs. laddningar i vila, i likformig rörelse och i acceleration. Dessa krafter benämns elektrisk, magnetisk respektive induktiv. Vi behandlar alltså dessa växelverkningar sammanhållet och formulerar de kraftformler som beskriver observationer och mätningar.

    De följande kapitlen är mer eller mindre raka tillämpningar av kraftformlerna. Begreppet energi, som införs i kapitel 3, utgår ifrån och är en direkt konsekvens av kraft via begreppet arbete. Vi visar hur denna princip tillämpas för både elektrisk och magnetisk energi. Kapitel 4 behandlar makroskopiska system vars egenskaper erhålls via en summering av ömsesidiga växelverkningar mellan infinitesimala element. I tillämpningar är systemen ofta homogena och beräkningarna kan då förenklas med hjälp av de geometriska kvantiteterna kapacitans och induktans. I kapitel 5 och 6 diskuteras ledaren och elektriska kretsar vilket utgör den experimentella miljö ur vilken elektrodynamiken har utvecklats och tekniska tillämpningar har sitt ursprung. Vi behandlar först den mikroskopiska beskrivningen av elektrisk ledning, resistansens ursprung och dess relation till värmeutveckling. Vidare diskuteras resonanskretsen och de övriga två kretskomponenterna: kapacitans och induktans.

    I kapitel 7 introduceras den elektriska och magnetiska dipolen, väsentliga begrepp eftersom naturen vanligen är konstruerad eller kan åtminstone approximeras till att bestå av dylika objekt. Centralt är då uttrycken för elektrisk och magnetisk dipol-dipolväxelverkan. Dessa är fundamentala för naturens dynamik. I kapitel 8 studerar vi hur olika elektriskt och magnetiskt neutrala material responderar på elektrisk och magnetisk påverkan och utgår då ifrån att materialet är uppbyggt av dipoler. Den matematiskt strikta behandlingen av dipol-, eller generellt multipol-, växelverkan presenteras i tillhörande appendix A och B.

    I kapitel 9 visar vi konceptuellt hur den magnetiska och induktiva dynamiken följer som rörelsekonsekvenser av den elektriska under antagandet att växelverkningar tar tid, de förmedlas med ljusets fart. Alternativt kan man utifrån kännedom om elektrisk och magnetisk kraft härleda ljusets fart. Vi kommer i ett specialfall kunna härleda såväl den magnetiska kraften som Faraday- Henrys induktionslag. Vidare visas hur elektrodynamiken är relaterad till relativitetsteorin. Faktum är att magnetism är den rörelsekonsekvens på vilken den speciella relativitetsteorin baseras. Eftersom vi utgår ifrån begreppet kraft är materialet unikt för denna bok.

    I kapitel 9 introduceras också Lorentz-tranformationer i form av en handledning för att självständigt kunna utveckla denna den formella basen för speciell relativitetsteori. Förkunskaper till kapitel 9 är endast kapitel 1-3 varför dessa fyra kapitel kan utgöra en kortkurs inom basal elektrodynamik och dess relation till relativitetsteori. I kapitel 10, slutligen, introduceras fältteorin för elektrodynamiken vilket leder oss till Maxwells ekvationer, grunden för den elektrobaserade ingenjörsvetenskapen. Fälten är förvisso redan definierade genom kraftformlerna, men uttrycks i Maxwells ekvationer som sin divergens och rotation. Vi motiverar detta genom att visa att fältens randvillkor är på så sätt givna.

    Ett viktigt särdrag hos denna bok är sålunda att fältteorin introduceras det att de fysiska fenomen som utgör elektrodynamiken beskrivits, tolkats och behandlats i termer av de grundläggande krafterna.

  • 29.
    Prytz, Kjell
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    Evidence for Gluon Recombination in Deep Inelastic Scattering2001Report (Other academic)
  • 30.
    Prytz, Kjell
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    Gravitationen, Elektromagnetismen, Kvantmekaniken och Ljuset2001Report (Other academic)
  • 31.
    Prytz, Kjell
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    Gravitationen, elektromagnetismen, kvantmekaniken och ljuset2001In: Elementa : tidskrift för matematik, fysik och kemi, ISSN 0013-5933, Vol. 84, no 3, p. 13p. 103-114Article in journal (Other academic)
  • 32.
    Prytz, Kjell
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    Numerical Solution to the coupled integro-differential Equations of Quantum Chromodynamics2003Report (Other academic)
  • 33.
    Prytz, Kjell
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    Om att intressera för fysik2003Report (Other academic)
  • 34.
    Prytz, Kjell
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    Om att intressera för fysik2003In: Elementa : tidskrift för matematik, fysik och kemi, ISSN 0013-5933, Vol. 86, no 2, p. 8p. 70-79Article in journal (Other academic)
  • 35.
    Prytz, Kjell
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Physics.
    On the origin of electromagnetic induction2012In: Galilean Electrodynamics, ISSN 1047-4811, Vol. 23, no 5, p. 99-Article in journal (Refereed)
  • 36.
    Prytz, Kjell
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    Signals of Gluon Recombination in Deep Inelastic Scattering2001Report (Other academic)
  • 37.
    Prytz, Kjell
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    Signals of gluon recombination in deep inelastic scattering2001In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 22, no 2, p. 8p. 317-321Article in journal (Refereed)
    Abstract [en]

    The notion of a pomeron structure function arises in a model of electromagnetic diffractive scattering based on Regge factorization. Due to its small size we expect gluon recombination to occur significantly in the pomeron. The latest data from H1 (1999) show a Q(2) evolution in qualitative accordance with the GLR-MQ equations; these are the DGLAP (Altarelli-Parisi) equations corrected for the effect of gluon recombination.

  • 38.
    Prytz, Kjell
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Physics.
    Sources of inertia in an expanding universe2015In: OPEN PHYSICS, ISSN 2391-5471, Vol. 13, no 1, p. 130-134Article in journal (Refereed)
    Abstract [en]

    In a cosmological perspective, gravitational induction is explored as a source to mechanical inertia in line with Mach's principle. Within the standard model of cosmos, considering the expansion of the universe and the necessity of retarded interactions, it is found that the assumed dynamics may account for a significant part of an object's inertia.

  • 39.
    Råsander, Mikael
    et al.
    Department of Materials, Imperial College London, London, UK.
    Hugosson, Håkan W.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Physics.
    Delin, Anna
    Department of Applied Physics, Kungliga Tekniska Hogskolan, Stockholm, Sweden.
    Density functional study of carbon vacancies in titanium carbide2018In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 30, no 1, article id 015702Article in journal (Refereed)
    Abstract [en]

    It is well established that TiC contains carbon vacancies not only in carbon-deficient environments but also in carbon-rich environments. We have performed density functional calculations of the vacancy formation energy in TiC for C- as well as Ti-rich conditions using several different approximations to the exchange-correlation functional, and also carefully considering the nature and thermodynamics of the carbon reference state, as well as the effect of varying growth conditions. We find that the formation of carbon vacancies is clearly favorable under Ti-rich conditions, whereas it is slightly energetically unfavorable under C-rich conditions. Furthermore, we find that the relaxations of the atoms close to the vacancy site are rather long-ranged, and that these relaxations contribute significantly to the stabilization of the vacancy. Since carbon vacancies in TiC are experimentally observed also in carbon-rich environments, we conclude that kinetics may play an important role. This conclusion is consistent with the experimentally observed high activation energies and sluggish diffusion of vacancies in TiC, effectively causing a freezing in of the vacancies.&#13.

  • 40.
    Rönnow, Daniel
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Determination of interface roughness cross correlation of thin films from spectroscopic light scattering measurements1997In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 81, no 8, p. 3627-3636Article in journal (Refereed)
    Abstract [en]

    Diffuse reflectance and transmittance spectra collected in different scattering angle intervals have been analyzed in order to determine the interface roughness cross correlation of thin films. Different angle intervals correspond to different roughness length scales; the cross correlation as a function of length scale can hence be determined. Sputter deposited ZrO2 films were analyzed. The transition from correlated to uncorrelated film interfaces was found to occur at longer length scales, when the film thickness increased.

  • 41.
    Rönnow, Daniel
    Department of Technology, Uppsala University, Uppsala, Sweden; Max-Planck-Institut für , Stuttgart, Germany.
    Interface roughness statistics of thin films from angle-resolved light scattering at three wavelengths1998In: Optical Engineering: The Journal of SPIE, ISSN 0091-3286, E-ISSN 1560-2303, Vol. 37, no 2, p. 696-704Article in journal (Refereed)
    Abstract [en]

    The possibility of determining interface roughness and cross-correlation statistics of the two interfaces of a thin film from angle-resolved light scattering data at three wavelengths is investigated. It is shown that angle-resolved light scattering measurements at three wavelengths are not sufficient to determine the three power spectral density functions describing the thin film roughness. An attempt to combine reflectance and transmittance scattering to determine the roughness of a thin film on a transparent substrate appears to work and provides encouraging results.

  • 42.
    Rönnow, Daniel
    et al.
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Andersson, S. K.
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Niklasson, G. A.
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Surface Roughness Effects in Ellipsometry: Comparison of Truncated Sphere and Effective Medium Models1995In: Optical materials (Amsterdam), ISSN 0925-3467, E-ISSN 1873-1252, Vol. 4, no 6, p. 815-821Article in journal (Refereed)
    Abstract [en]

    We investigate the applicability of effective medium models for describing the effects of surface roughness on ellipsometric data. The ellipsometric parameters of a model surface composed of truncated spherical bumps on a substrate were calculated and compared to the Bruggeman effective medium theory. It is possible to fit the model calculations with the Bruggeman theory. However, the thickness and volume fraction of the effective medium layer describing the surface roughness do not correspond to the physical height and volume fraction of the bumps on the model surface.

  • 43.
    Rönnow, Daniel
    et al.
    Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
    Cardona, M.
    Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
    Lastras-Martínez, L. F.
    Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
    Piezo-optical coefficients of ZnSe and ZnTe above the fundamental gap1999In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 59, no 8, p. 5581-5590Article in journal (Refereed)
    Abstract [en]

    The piezo-optical coefficients P11-P12 and P44 have been measured for ZnSe and ZnTe above the fundamental gap (in the energy ranges 2.6-5.5 eV and 2.0-5.5 eV, respectively) by using reflectance difference spectroscopy. The measured spectra of P11-P12 and P44 show good Kramers-Kronig consistency between their real and imaginary parts. Values for the deformation potentials D1 5, D3 3, and D3 5 for the E1 and E1 + Δ1 transitions were estimated by fitting the spectral dependence of P11-P12 and P44 to analytical line shapes based on a one-electron approximation.

  • 44.
    Rönnow, Daniel
    et al.
    Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
    Christensen, N. E.
    Institute of Physics and Astronomy, Århus University, Århus, Denmar.
    Cardona, M.
    Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
    Deformation potentials of the E1 transition in Ge, GaAs, InP, ZnSe, and ZnTe from ab initio calculations1999In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 59, no 8, p. 5575-5580Article in journal (Refereed)
    Abstract [en]

    The deformation potentials D1 1, D3 3, D1 5, and D3 5, which represent the effects of strain on the E1 electronic interband transitions, have been calculated for Ge, GaAs, InP, ZnSe, and ZnTe using the full-potential linear muffin-tin orbital method within the local-density approximation. These deformation potentials exhibit no strong variations between L and Γ throughout the Brillouin zone. It is therefore legitimate to use an average to interpret strain-optical experiments. The values of these deformation potentials are approximately the same for all calculated materials. The agreement with experimental data is good for Ge, GaAs, and InP. For ZnSe and ZnTe the agreement with the few extant experimental data is poorer: The magnitude of the calculated deformation potentials is smaller than found experimentally. This may reflect a breakdown of the conventional theory of strain optical constants based on one-electron interband transitions. The corresponding deformation potentials, D1,0 5 and D3,0 5, representing the effects of optical phonons at the center of the Brillouin zone on the E1 transitions are also presented.

  • 45.
    Rönnow, Daniel
    et al.
    Department of Materials Science, Uppsala University, Uppsala, Sweden.
    Eisenhammer, T.
    TiNOX GmbH, München, Germany.
    Roos, A.
    Department of Materials Science, Uppsala University, Uppsala, Sweden.
    Surface roughness characterisation of a thin transparent dielectric-silver tandem by spectroscopic light scattering1998In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 52, no 1-2, p. 37-43Article in journal (Refereed)
    Abstract [en]

    Spectroscopic light scattering was measured on a system of a dielectric layer on top of a thin (13 nm) silver film on a glass substrate. The analysis included both forward and backward scattering and excellent agreement between measured and modelled results was achieved. The theoretical analysis showed that the film interfaces were correlated, i.e. the substrate roughness was replicated, and that the interface roughness (root mean square) was in the nanometer range.

  • 46.
    Rönnow, Daniel
    et al.
    Department of technology, Uppsala university, Uppsala, Sweden.
    Isidorsson, J.
    Department of technology, Uppsala university, Uppsala, Sweden.
    Niklasson, G. A.
    Department of technology, Uppsala university, Uppsala, Sweden.
    Surface Roughness of Sputtered ZrO2 Films Studied by Atomic Force Microscopy and Spectroscopic Light Scattering1996In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, ISSN 1063-651X, E-ISSN 1095-3787, Vol. 54, no 4 Suppl. B, p. 4021-4026Article in journal (Refereed)
    Abstract [en]

    ZrO2 films were prepared by reactive sputtering. Elastic light scattering was used to determine the cross correlation of the substrate and film interface roughness. Surface profiles were measured with atomic-force microscopy. The power spectral density functions could be fitted by the K-correlation model, suggesting self-affine fractal surfaces. The roughness of the film front surfaces was of the same order of magnitude as the substrate roughness. We have derived a replication factor from experimental data that gives information on the evolution of the contribution of the substrate roughness.

  • 47.
    Rönnow, Daniel
    et al.
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Kullman, L.
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Granqvist, C. G.
    Department of Technology, Uppsala University, Uppsala, Sweden.
    Spectroscopic Light Scattering from Electrochromic Tungsten-oxide-based Films1996In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 80, no 1, p. 423-430Article in journal (Refereed)
    Abstract [en]

    Films of W oxide and oxyfluoride were made by reactive sputtering, and electrochromic absorption modulation was obtained by subsequent electrochemical Li intercalation. Total and diffuse transmittance and reflectance were measured in the 0.4-1 μm wavelength range using a newly developed instrument. The ratio between diffuse and total optical response was <0.2% for the transmittance and <1% for the reflectance irrespective of the electrochromic absorption level. These magnitudes of the scattering are acceptable for practical smart windows applications and lend credence to a description of electrochromism in terms of localized absorption centers. Vector perturbation theory for light scattering by a film with rough interfaces could be reconciled with the data, assuming uncorrelated roughness.

  • 48.
    Rönnow, Daniel
    et al.
    Max Planck Institut für Festkörperforschung, Stuttgart, Germany.
    Lastras-Martí­nez, L. F.
    Max Planck Institut für Festkörperforschung, Stuttgart, Germany.
    Cardona, M.
    Max Planck Institut für Festkörperforschung, Stuttgart, Germany.
    Isotope effects on the electronic critical points of germanium: Ellipsometric investigation of the E1 and E1+ Delta(1) transitions1998In: European Physical Journal B: Condensed Matter Physics, ISSN 1434-6028, E-ISSN 1434-6036, Vol. 5, no 1, p. 29-35Article in journal (Refereed)
    Abstract [en]

    Within the past years the optical excitations of electrons have been measured for semiconductor samples of different isotope compositions. The isotope shift observed have been compared with calculations of the effects of electron-phonon interaction on the electronic band structure. While qualitative agreement has been obtained, some discrepancies remain especially concerning the E1 and E1 + Delta(1) transitions. We have remeasured the effect of isotope mass on the E1 and E1 + Delta(1) transitions of germanium with several isotopic compositions. The results, obtained by means of spectroscopic ellipsometry, confirm that the real part of the gap self-energies induced by electron-phonon interaction is larger than found from band structure calculations, while the imaginary part agrees with those calculations, which are based on a pseudopotential band structure and a bond charge model for the lattice dynamics. Our results agree with predictions based on the measured temperature dependence of the gaps. We compare our data for E1 and E1 + Delta(1) with results for the lowest direct (E0) and indirect (E9) gaps. The measured values of Δ0 and Δ1 increase noticeably with increasing isotope mass. Similar effects have been observed in the temperature dependence of Delta(1) in alpha-Sn and GaSb. A microscopic explanation for this effect is not available.

  • 49.
    Rönnow, Daniel
    et al.
    Max Planck Institut für Festkörperforschung, Stuttgart, Germany.
    Lindström, T.
    Department of Materials Science, Uppsala University, Uppsala, Sweden.
    Isidorsson, J.
    Department of Materials Science, Uppsala University, Uppsala, Sweden.
    Ribbing, C.-G.
    Department of Materials Science, Uppsala University, Uppsala, Sweden.
    Surface roughness of oxidised copper films studied by atomic force microscopy and spectroscopic light scattering1998In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 325, no 1-2, p. 92-98Article in journal (Refereed)
    Abstract [en]

    The interface roughness of Cu2O films produced by thermal oxidation of Cu was studied by spectroscopic elastic light scattering and atomic force microscopy. No correlation could be found between the roughness of the two interfaces, although the amplitude and the length scale of the roughness changed in the same way with film thickness for both interfaces. Both interfaces were found to have a fractal dimension of two. A first order perturbation theory was used to analyse the light scattering data; theory and experiment are in good agreement within the limits of the theory.

  • 50.
    Rönnow, Daniel
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics. Uppsala University, Department of Technology, Uppsala, Sweden.
    Roos, A.
    Uppsala University, Department of Technology, Uppsala, Sweden.
    Correction Factors for Reflectance and Transmittance Measurements of Scattering Samples in Focussing Coblentz Spheres and Integrating Spheres1995In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 66, no 3, p. 2411-2422Article in journal (Refereed)
    Abstract [en]

    The detector signals from a total integrated scatter (TIS) instrument, which uses a focusing Coblentz sphere, have been evaluated. Models for the calculation of correct reflectance and transmittance values for both scattering and nonscattering samples are presented. In particular, the correction for multiple reflections between sample and detector, the detector efficiency versus angle of incidence, and the symmetry properties of the Coblentz sphere have been investigated. Experimental results are compared with results obtained with an integrating sphere using a model for the correction of sphere asymmetry. The results show that the transmittance and reflectance values obtained with the TIS instrument and the integrating sphere agree only when the presented correction factors are properly taken into account.

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