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  • 1.
    Abedin, Ahmad
    et al.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Moeen, Mahdi
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Cappetta, Carmine
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Radamson, Henry H.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Sensitivity of the crystal quality of SiGe layers grown at low temperatures by trisilane and germane2016In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 613, p. 38-42Article in journal (Refereed)
    Abstract [en]

    This work investigates the crystal quality of SiGe layers grown at low temperatures using trisilane, and germane precursors. The crystal quality sensitivity was monitored for hydrogen chloride and/or minor oxygen amount during SiGe epitaxy or at the interface of SiGe/Si layers. The quality of the epi-layerswas examined by quantifying noise parameter, K-1/f obtained from the power spectral density vs. 1/f curves. The results indicate that while it is difficult to detect small defect densities in SiGe layers by physical material characterization, the noise measurement could reveal the effects of oxygen contamination as low as 0.16mPa inside and in the interface of the layers.

  • 2.
    Aggerstam, Thomas
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Electrum Laboratory, ELAB.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Centres, Electrum Laboratory, ELAB.
    Radamson, Henry H.
    KTH, School of Information and Communication Technology (ICT), Centres, Electrum Laboratory, ELAB.
    Sjödin, Mikael
    KTH, School of Information and Communication Technology (ICT), Centres, Electrum Laboratory, ELAB.
    Lorenzini, P.
    CNRS-CHREA.
    Look, D.C.
    Semiconductor Research Center, Wright State University.
    Investigation of the interface properties of MOVPE grown AlGaN/GaN high electron mobility transistor (HEMT) structures on sapphire2006In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 2, p. 705-707Article in journal (Refereed)
    Abstract [en]

    We have developed a virtual GaN substrate on sapphire based on a two-step growth method. By optimizing the growth scheme for the virtual substrate we have improved crystal quality and reduced interface roughness. Our Al0.22Ga0.78N/GaN HEMT structure grown on the optimized semi-insulating GaN virtual substrate, exhibits Hall mobilities as high as 1720 and 7350 cm(2)/Vs and sheet carrier concentrations of 8.4 x 1012 and 10.0 x 1012 cm(-2) at 300 K and 20 K, respectively The presence of good AlGaN/GaN interface quality and surface morphology is also substantiated by X-Ray reflectivity and Atomic Force Microscopy measurements. A simplified transport model is used to fit the experimental Hall mobility.

  • 3. Agnarsson, Björn
    et al.
    Magnus, Fridrik
    Tryggvason, T. K.
    Ingason, Arni S.
    Leosson, K
    Olafsson, S
    Gudmundsson, Jon Tomas
    University of Iceland.
    Rutile TiO2 thin films grown by reactive high power impulse magnetron sputtering2013In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 545, p. 445-450Article in journal (Refereed)
  • 4.
    Agnarsson, Björn
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Qi, B.
    Götelid, Mats
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Olafsson, S.
    Gislason, H. P.
    The effect of hard nitridation on Al(2)O(3) using a radio frequency operated plasma cell2011In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 519, no 22, p. 7796-7802Article in journal (Refereed)
    Abstract [en]

    We report on an atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) investigation of hard nitridation of sapphire (alpha.-Al(2)O(3)) substrate, using an Epi UNI-Bulb RF plasma cell at substrate temperatures ranging from 250 to 600 degrees C. Our results show that an AlN(1-x)O(x) layer forms on sapphire after extended nitridation at all temperatures, following a Stranski-Krastanov growth mode, with less islands forming at higher temperatures. We also observe a layer-dependent charging shift in XPS, separating smooth AlN(1-x)O(x) layers from rough AlN(1-x)O(x) islands due to their different electronic coupling to the substrate. Although the island growth is suppressed at higher temperatures, the surface roughness increases at higher temperatures as seen by AFM. We also observe sputtering effects with protrusions and pits.

  • 5.
    Agnarsson, Björn
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Qi, B.
    Szamota-Leandersson, Karolina
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Olafsson, S.
    Göthelid, Mats
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Investigation on the role of indium in the removal of metallic gallium from soft and hard sputtered GaN (0001) surfaces2009In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 517, no 21, p. 6023-6026Article in journal (Refereed)
    Abstract [en]

    Cleaning of GaN by argon sputtering and subsequent annealing introduces metallic gallium on the GaN surface. Once formed, this metallic gallium can be difficult to remove. it has a strong influence on the Fermi level position in the band gap and poses a problem for subsequent epitaxial growth on the surface. We present a method of removing metallic gallium from moderately damaged GaN surfaces by deposition of indium, and formation of an In-Ga alloy that can be desorbed by annealing at similar to 550 degrees C. After the In-Ga alloy has desorbed, photoemission spectra show that the Ga3d bulk component becomes narrower indicating a smoother and more homogeneous surface. This is also reflected in a sharper low energy electron diffraction pattern. On heavily damaged GaN surfaces, caused by hard sputtering, larger amount of metallic gallium forms after annealing at 600 degrees C. This gallium readily alloys with deposited indium, but the alloy does not desorb until a temperature of 840 degrees C is reached and even then, traces of both indium and metallic gallium could be found on the surface.

  • 6. Astrath, N. G. C.
    et al.
    Bento, A. C.
    Baesso, M. L.
    da Silva, A. Ferreira
    Persson, Clas
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Photoacoustic spectroscopy to determine the optical properties of thin film 4H-SiC2006In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 4, p. 2821-2823Article in journal (Refereed)
    Abstract [en]

    The optical transitions in a range of 1.5-5.2 eV of n-type 4H-SiC have been investigated experimentally by photoacoustic spectroscopy and theoretically by a full-potential linearized augmented plane wave method. From the absorption spectrum, we found the indirect optical bandgap at 3.2 eV and the direct transitions around 4.5 eV in very good agreement with what has been predicted by theoretical calculations.

  • 7.
    Azarov, Alexander
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Zamani, Atieh
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Radamson, Henry H.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Vines, L.
    Kuznetsov, A. Yu.
    Hallén, Anders
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Dopant incorporation in thin strained Si layers implanted with Sb2010In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 518, no 9, p. 2474-2477Article in journal (Refereed)
    Abstract [en]

    The effect of tensile strain on Sb incorporation in Si and its activation during post-implantation annealing has been Studied by a combination of Rutherford backscattering/channeling spectrometry, secondary ion mass spectrometry. X-ray diffraction and 4-point probe measurements Our results show that, for Sb implanted samples a tensile strain has an important role for dopant behavior Particularly, increasing the tensile strain in the Si layer from 0 to 0 8% leads to an enhancement of the fraction of incorporated Sb atoms in substitutional sites already during implantation from similar to 7 to 30% Furthermore, 0 8% strain in antimony doped Si gives similar to 20% reduction in the sheet resistance in comparison to the unstrained sample.

  • 8. Baudin, M.
    et al.
    Wojcik, M.
    Hermansson, Kersti
    KTH, Superseded Departments, Biotechnology.
    Molecular dynamics simulations of an Al2O3(0001 +/-, 0-10(II))/CeO2 (011 +/-,01-1(II)) interface system2001In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 401, no 02-jan, p. 159-164Article in journal (Refereed)
    Abstract [en]

    Constant stress, constant temperature (10 K, 300 K) molecular dynamics simulations were carried out with shell-model potentials for an infinite composite ceria-alumina slab with two free surfaces [alpha -Al2O3 (0001) and CeO2(011) and their opposite counterparts]. The interface introduces considerable structural and dynamical changes, both at the slab surfaces and in the center of the slab. Structurally, both oxide surfaces become effectively oxygen-terminated and the surface structures become disordered close to the interface. Dynamically, in the region near the 'alumina surface/ceria surface/alumina-ceria interface' 3-phase junction the ionic motion is considerably enhanced. Thus, in the interface region, the ionic mean-square displacements increase 2-3 times compared to the pure slabs. Moreover, the ions at the interface participate in a new kind of motion, not present in the pure oxide slabs: large occasional, but frequently reoccurring, back-and-forth ionic motions take place with square-amplitudes as large as similar to0.70 Angstrom (2).

  • 9. Bennett, N. S.
    et al.
    Radamson, Henry H.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Beer, C. S.
    Smith, A. J.
    Gwilliam, R. M.
    Cowern, N. E. B.
    Sealy, B. J.
    Enhanced n-type dopant solubility in tensile-strained Si2008In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 517, no 1, p. 331-333Article in journal (Refereed)
    Abstract [en]

    The creation of highly conductive ultrashallow-doped regions in strained Si is a key requirement for future Si based devices. It is shown that in the presence of tensile strain, Sb becomes a contender to replace As in strain-engineered CMOS devices due to advantages in sheet resistance. While strain reduces resistance for both As and Sb; a result of enhanced electron mobility, the reduction is significantly larger for Sb due to an increase in donor activation. Differential Hall measurements suggest this is a consequence of a strain-induced Sb solubility enhancement following solid-phase epitaxial regrowth, increasing Sb solubility in Si to levels approaching 10(21) cm(-3). Experiments highlight the importance of maintaining substrate strain during thermal annealing to maintain this high Sb activation.

  • 10. Bexell, U.
    et al.
    Berger, R.
    Olsson, M.
    Grehk, T. M.
    Sundell, P. E.
    Johansson, Mats K. G.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Bonding of vegetable oils to mercapto silane treated metal surfaces: Surface engineering on the nano scale2006In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 2, p. 838-841Article in journal (Refereed)
    Abstract [en]

    In this paper the bonding of thin vegetable oil films on mercapto silane treated aluminium surfaces has been studied. The silane molecules are attached to the surface by metal-oxygen-silicon bonds. The coupling between the unsaturated bonds of the vegetable oil and the thiol functionalised surface was obtained through a photoinduced thiol-ene reaction. The surfaces were characterised by X-ray photoelectron spectroscopy (XPS). Vegetable oil contains both saturated and unsaturated carbon chains. For the reactions investigated in this study it is the unsaturated carbon chains that can react by a thiol-ene reaction and the results indicate that it is possible to attach a vegetable oil to a metal surface pre-treated with a thiol functionalised silane.

  • 11.
    Björck, M.
    et al.
    Uppsala Universitet.
    Soroka, Inna
    Uppsala Universitet.
    Chacon-Carillo, C.
    Universite Paris, France.
    Andersson, G.
    Uppsala Universitet.
    The asymmetric interface structure of bcc Fe82Ni18/Co superlattices as revealed by neutron diffraction2007In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 7-8, p. 3619-3623Article in journal (Refereed)
    Abstract [en]

    The interface structure of Fe82Ni18/Co (001) superlattices was studied by a combination of X-ray and neutron diffraction. The anal. revealed highly asym. interfaces with total interface widths of 10±1 ML (monolayers) for Fe82Ni18 on Co and a max. interface width of 1 ML for Co on Fe82Ni18. In addn., there was no detectable long range B2-type chem. order occurring in the interface region. These results are discussed in the context of previously measured magnetic moments of the same system.

  • 12. Bohlmark, J.
    et al.
    Lattemann, M.
    Gudmundsson, J. T.
    Ehiasarian, A. P.
    Gonzalvo, Y. Aranda
    Brenning, Nils
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Helmersson, U.
    The ion energy distributions and ion flux composition from a high power impulse magnetron sputtering discharge2006In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 4, p. 1522-1526Article in journal (Refereed)
    Abstract [en]

    The energy distribution of sputtered and ionized metal atoms as well as ions from the sputtering gas is reported for a high power impulse magnetron sputtering (HIPIMS) discharge. High power pulses were applied to a conventional planar circular magnetron Ti target. The peak power on the target surface was 1-2 kW/cm(2) with a duty factor of about 0.5%. Time resolved, and time averaged ion energy distributions were recorded with an energy resolving quadrupole mass spectrometer. The ion energy distributions recorded for the HIPIMS discharge are broader with maximum detected energy of 100 eV and contain a larger fraction of highly energetic ions (about 50% with E-i > 20 eV) as compared to a conventional direct current magnetron sputtering discharge. The composition of the ion flux was also determined, and reveals a high metal fraction. During the most intense moment of the discharge, the ionic flux consisted of approximately 50% Ti1+, 24% Ti2+, 23% Ar1+, and 3% Ar2+ ions.

  • 13. Boschloo, G.
    et al.
    Marinado, T.
    Nonomura, K.
    Edvinsson, T.
    Agrios, A. G.
    Hagberg, D. P.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Quintana, M.
    Karthikeyan, C. S.
    Thelakkat, M.
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    A comparative study of a polyene-diphenylaniline dye and Ru(dcbpy)(2)(NCS)(2) in electrolyte-based and solid-state dye-sensitized solar cells2008In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 516, no 20, p. 7214-7217Article in journal (Refereed)
    Abstract [en]

    A small organic sensitizer, the polyene-diphenylaniline dye D5, was compared with the standard sensitizer N719 (Ru(dcbPY)(2)(NCS)(2)) in a dyesensitized solar cell investigation. In solar cells with relatively thin layers of mesoporous TiO2 (< 3 mu m) D5 outperformed N719 because of its high extinction coefficient. D5 showed also better performance than N719 in the case of sensitization of mesoporous ZnO. In solid-state solar cells, where the iodide/triiodide electrolyte was replaced by an amorphous hole conductor (spiro-OMeTAD), D5 gave promising preliminary results. The hole conductivity, observed in monolayers of D5 adsorbed at TiO2, may possibly lead to improved performance in such cells.

  • 14.
    Canestraro, Carla Daniele
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Roman, Lucimara S.
    Departamento de Física, Universidade Federal do Paraná.
    Persson, Clas
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Polarization dependence of the optical response in SnO2 and the effects from heavily F doping2009In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 517, no 23, p. 6301-6304Article in journal (Refereed)
    Abstract [en]

    The optical properties of intrinsic SnO2 (TO) and fluorine doped (FTO) are characterized in terms of the dielectric function epsilon(h omega) = epsilon(1) (h omega) + i epsilon(2)(h omega) by electronic structure calculations. The intrinsic TO shows intriguing absorption characteristics in the 3.0-8.0 eV region: (i) the low energy region of the fundamental band gap (3.2<h omega<3.9 eV), the optical transitions Gamma(+)(3) -> Gamma(+)(1) (valence-band maximum to conduction-band minimum) is symmetry forbidden, and the band-edge absorption is therefore extremely weak. (ii) In the higher energy region (3.9<h omega<5.1 eV) the Gamma(-)(5) -> Gamma(+)(1), transitions (from the second uppermost valence band) is strongly polarized perpendicular to the main c axis. (iii) Transitions with polarization axis parallel to c axis are generated from Gamma(-)(2) -> Gamma(+)(1) transitions (from the third uppermost valence bands), and dominates at high energies (5.1<h omega eV). Heavily F doped TO (FTO) with doping concentrations n(F) = 4 x 10(20) cm(-3) changes the absorption significantly: (iv) Substitutional F-O generates strong inter-conduction band absorption at 0.8, 2.2, and 3.8 eV which affects also the high frequency dielectric constant epsilon(infinity). (v) Interstitial F-i is inactive as a single dopant, but act as a compensating acceptor in highly n-type FTO. This explains the measured non-linear dependence of the resistivity with respect to F concentration.

  • 15.
    Chen, Rongzhen
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Persson, Clas
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Parameterization of CuIn1-xGaxSe2 (x=0, 0.5, and 1) energy bands2011In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 519, no 21, p. 7503-7507Article in journal (Refereed)
    Abstract [en]

    Parameterization of the electronic band structure of CuIn(1-x)Ga(x)Se(2) (x=0, 0.5, and 1) demonstrates that the energy dispersions of the three uppermost valence bands [E(j)(k); j=v1, v2, and v3] are strongly anisotropic and non-parabolic even very close to the Gamma-point valence-band maximum E,(0). Also the lowest conduction band E(c1) (k) is anisotropic and non-parabolic for energies similar to 0.05 eV above the band-gap energy. Since the electrical conductivity depends directly on the energy dispersion, future electron and hole transport simulations of CuIn(1-x)Ga(x)Se(2) need to go beyond the parabolic approximation of the bands. We therefore present a parameterization of the energy bands, the k-dependency of the effective electron and hole masses m(f)(k), and also an average energy-dependent approximation of the masses m(j)(E).

  • 16.
    Douheret, Olivier
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Maknys, Kestutis
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Anand, Srinivasan
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Scanning capacitance microscopy investigations of lnGaAs/InP quantum wells2004In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 459, no 02-jan, p. 67-70Article in journal (Refereed)
    Abstract [en]

    In this work, cross-sectional scanning capacitance microscopy (SCM) is used to investigate InGaAs/InP (latticed matched) quantum wells grown by metal-organic vapor phase epitaxy. Using n-doped InP as barriers with different doping levels, different InGaAs wells structures (5, 10 and 20 nm) were investigated. The capability of SCM to detect electrons in the quantum wells is demonstrated, showing in addition, a systematic and consistent trend for the different well widths and barrier doping levels. The SCM results are qualitatively consistent with electron distribution obtained for 1D Poisson/Schrodinger simulation. Finally, resolution issues in SCM are discussed in terms of tip averaging effects.

  • 17. Dutta, Joydeep
    et al.
    Ray, S.
    Variations in structural and electrical properties of magnetron-sputtered indium tin oxide films with deposition parameters1988In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 162, no C, p. 119-127Article in journal (Refereed)
  • 18.
    Dzibrou, Dzmitry
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Grishin, Alexander
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Kawasaki, H.
    Pulsed Laser Deposited TiO2Films: Tailoring optical properties2008In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 516, no 23, p. 8697-8701Article in journal (Refereed)
    Abstract [en]

    TiO2 amorphous films have been pulsed laser deposited onto glass substrates. Film characterization by X-ray diffraction, atomic force microscopy and transmission spectroscopy was performed with the aim of extracting the information on the film crystalline structure, surface roughness and optical properties. Three methods for improving film optical performance have been employed, namely deposition at elevated temperatures, post-annealing in thermodynamically equilibrium conditions and rapid thermal annealing (RTA). The best characteristics were achieved in the case of the film subjected to RTA at 500 °C: refractive index n = 2.53, absorption coefficient α = 404 cm- 1 at λ = 550 nm and rms surface roughness as low as 0.6 nm. The results obtained were found to be one of the best published so far.

  • 19.
    Fors, Rickard
    et al.
    KTH, Superseded Departments, Materials Science and Engineering.
    Khartsev, Sergiy
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Grishin, Alexander M.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Pohl, A.
    Westin, G.
    Sol-gel derived versus pulsed laser deposited epitaxial La0.67Ca0.33MnO3 films: structure, transport and effects of post-annealing2004In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 467, no 02-jan, p. 112-116Article in journal (Refereed)
    Abstract [en]

    Epitaxial La0.67Ca0.33MnO3 films have been prepared on LaAlO3 crystals by pulsed laser deposition (PLD) and by a novel all-alkoxide sol-gel technique. Different out-of-plane lattice parameters are found for the as-prepared films, and scanning electron microscopy shows a more porous structure for sol-gel films as compared to PLD films. These differences are largely removed by post annealing at 1000 degreesC. Transport measurements show maximum temperature coefficient of resistivity of 8.2% K-1 at 258 K (PLD) and 6.1% K-1 at 241 K (sol-gel) and colossal magnetoresistance at 560 kA/m of 35% at 263 K (PLD) and 32% at 246 K (sol-gel).

  • 20.
    Fu, Ying
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Multiple-photon spectrum of CdS semiconductor quantum dot for bioimaging2006In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 2, p. 842-845Article in journal (Refereed)
    Abstract [en]

    We study the dynamic processes of multiple-photon absorption and emission in a semiconductor quantum dot. By the non-perturbative time-dependent Schrodinger equation, it is shown that electrons in the quantum dot can be optically excited from the valence band to the conduction band via multiphoton processes, leaving holes in the valence band. The radiative recombination of the conduction-band electrons with the valence-band holes results in optical emission of a single photon having an energy which is larger than the input photon energy, resulting in the high-photon-energy luminescence from the quantum dot activated by low-energy photons to emit radiation in the visible optical regime for bioimaging application.

  • 21. Ghandi, R.
    et al.
    Kolahdouz, M.
    Hållstedt, Julius
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wise, R.
    Wejtmans, Hans
    Radamson, Henry H.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Effect of strain, substrate surface and growth rate on B-doping in selectively grown SiGe layers2008In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 517, no 1, p. 334-336Article in journal (Refereed)
    Abstract [en]

    In this work, the role of strain and growth rate on boron incorporation in selective epitaxial growth (SEG) of B-doped Si1-xGex (x=0.15-0.25) layers in recessed or unprocessed (elevated) openings for source/drain applications in CMOS has been studied. A focus has been made on the strain distribution and B incorporation in SEG of SiGe layers.

  • 22.
    Grishin, Alexander M.
    et al.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Khartsev, Sergiy I.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Green and blue magneto-optical photonic crystals2012In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 520, no 9, p. 3647-3650Article in journal (Refereed)
    Abstract [en]

    A series of one-dimensional heteroepitaxial all-garnet magneto-optical photonic crystals (MOPCs) were pulsed laser deposited to operate at 550 and 470 nm wavelength. We explored the concept of blue shift of the optical absorption edge of ferric ions by substituting Fe with Ga on the tetrahedral sites as well as Bi and Y, respectively, with Ca and Ce at the dodecahedral coordinated positions. 17-layered [Y2Ce1Fe5O12/Gd3Ga5O12] MOPC with a total thickness of 968 nm demonstrates superior magneto-optical performance: Faraday rotation theta(Fmax) = + 2.0 degrees and transmittance as high as 0.35 at the resonance wavelength of 470 nm.

  • 23. Grivickas, V.
    et al.
    Galeckas, A.
    Bikbajevas, V.
    Linnros, Jan
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Tellefsen, J. A.
    Spatially and time-resolved infrared absorption for optical and electrical characterization of indirect band gap semiconductors2000In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 364, no 02-jan, p. 181-185Article in journal (Refereed)
    Abstract [en]

    The current status of the spatially and time-resolved free-carrier absorption (FCA) method is provided. The FCA technique allows monitoring carrier dynamics in a time scale from nanoseconds to miliseconds by employing either collinear or orthogonal geometry between pump and probe beams. A high spatial resolution is achieved allowing in-depth carrier profiles to be extracted. The method is particularly suited for investigation of injection-dependent optical and recombination phenomena: band gap optical absorption, Shockley-Read-Hall (SRH) lifetime, Auger recombination coefficient, and the injection-dependent surface (interface) recombination velocity. We summarize important aspects of the technique demonstrating numerous measurements that have been implemented in studies of bulk Si, epilaxial 4H-SiC and porous silicon.

  • 24.
    Gylfason, Kristinn B.
    et al.
    Lyfjathroun Biopharmaceuticals, Iceland.
    Ingason, A. S.
    Agustsson, J. S.
    Olafsson, S.
    Johnsen, K.
    Gudmundsson, J. T.
    In-situ resistivity measurements during growth of ultra-thin Cr_0.7Mo_0.32006In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 2, p. 583-586Article in journal (Refereed)
    Abstract [en]

    The growth of ultra-thin, lattice matched, Cr0.7Mo0.3 films on an MgO substrate, in a dc magnetron discharge, was investigated by in situ measurements in order to determine the minimum thickness of a continuous layer. The thickness dependence of the resistivity shows a coalescence thickness of less than two monolayers indicating layer by layer growth of the films. We compare the resistivity of the films to a combination of the Fuchs- Sondheimer and the Mayadas-Shatzkes models, assuming a thickness dependence of grain size. The model indicates that grain size increases with increasing growth temperature.

  • 25.
    Hellgren, Niklas
    et al.
    Linköpings Universitet.
    Guo, Jinghua
    Lawrence Berkeley National Laboratory.
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Såthe, Conny
    Uppsala Universitet.
    Agui, Akane
    Uppsla Universitet.
    Kashtanov, Stepan
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Nordgren, Joseph
    Uppsla Universitet.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Sundgren, Jan- Eric
    Linköpings Universitet.
    Electronic structure of carbon nitride thin films studied by X-ray spectroscopy techniques2005In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 471, no 02-jan, p. 19-34Article in journal (Refereed)
    Abstract [en]

    Magnetron-sputtered carbon nitride thin films with different structures and compositions were analyzed by X-ray and ultraviolet photoelectron spectroscopy (XPS and UPS), near-edge X-ray absorption fine structure spectroscopy (NEXAFS), as well as X-ray emission spectroscopy (XES). In all techniques, the carbon spectra are broad and featureless with little variation depending on growth conditions. The nitrogen spectra, on the other hand, show more distinct features, providing a powerful tool for structural characterization. By comparing the experimental spectra with calculations on different model systems, we are able to identify three major bonding structures of the nitrogen-N1: nitrile (C equivalent to N) bonds; N2: Pyridine-like N, i.e., N bonded to two C atoms; and N3: graphite-like N, i.e., N bonded to three C atoms as if substituted in a graphitic network, however, possibly positioned in a pentagon and/or with sp(3) carbon neighbors. The presence of N2 and N3 are best detected by XPS, while N1 is better detected by NEXAFS. The calculated XES spectra also give good indications how valence band spectra should be interpreted. Films grown at the higher temperatures ( greater than or equal to 350 degreesC) show a pronounced angular dependence of the incoming photon beam in NEXATS measurements, which suggests a textured microstructure with standing graphitic basal planes, while amorphous films grown at low temperatures show isotropic properties.

  • 26. Helmersson, Ulf
    et al.
    Latteman, M
    Bohlmark, J
    Ehiasarian, A. P.
    Gudmundsson, Jon Tomas
    University of Iceland.
    Ionized Physical Vapor Deposition (IPVD): A Review of Technology and Applications2006In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 513, p. 1-24Article in journal (Refereed)
    Abstract [en]

    In plasma-based deposition processing, the importance of low-energy ion bombardment during thin film growth can hardly be exaggerated. Ion bombardment is an important physical tool available to materials scientists in the design of new materials and new structures. Glow discharges and in particular, the magnetron sputtering discharge have the advantage that the ions of the discharge are abundantly available to the deposition process. However, the ion chemistry is usually dominated by the ions of the inert sputtering gas while ions of the sputtered material are rare. Over the last few years, various ionized sputtering techniques have appeared that can achieve a high degree of ionization of the sputtered atoms, often up to 50% but in some cases as much as approximately 90%. This opens a complete new perspective in the engineering and design of new thin film materials. The development and application of magnetron sputtering systems for ionized physical vapor deposition (IPVD) is reviewed. The application of a secondary discharge, inductively coupled plasma magnetron sputtering (ICP-MS) and microwave amplified magnetron sputtering, is discussed as well as the high power impulse magnetron sputtering (HIPIMS), the self-sustained sputtering (SSS) magnetron, and the hollow cathode magnetron (HCM) sputtering discharges. Furthermore, filtered arc-deposition is discussed due to its importance as an IPVD technique. Examples of the importance of the IPVD-techniques for growth of thin films with improved adhesion, improved microstructures, improved coverage of complex shaped substrates, and increased reactivity with higher deposition rate in reactive processes are reviewed.

  • 27. Hirschauer, B
    et al.
    Chiaia, G
    Gothelid, M
    Karlsson, U O
    Studies of highly oriented CeO2 films grown on Si(111) by pulsed laser deposition1999In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 348, no 1-2, p. 3-7Article in journal (Refereed)
    Abstract [en]

    CeO2 is an interesting buffer layer material for the growth of YBa(2)Cu(3)O(7-)delta overlayers on Si in devices, with the aim of preventing heat-diffusion due to its excellent lattice matching with Si and YBa(2)Cu(3)O(7-)delta. Epitaxial CeO2-films have been synthesised on Si(lll) by pulsed laser deposition. Stoichiometric changes of the CexOy-film depending on the ambient oxygen pressure during the deposition were studied by X-ray photoelectron spectroscopy. A method is presented for growing a sharp interface between CeO2 and Si(111). The dependence of the inplane orientation of the CeO2 film on the substrate temperature was investigated by X-ray diffraction. The best films, grown at 700 degrees C, showed full width at half maximum of the rocking curve close to 0.1 degrees, but already at room temperature very highly oriented films with less than 0.2 degrees were synthesised. (C) 1999 Elsevier Science S,A. All rights reserved.

  • 28. Hirschauer, B
    et al.
    Soderholm, S
    Chiaia, G
    Karlsson, Ulf O
    Highly oriented alpha-alumina films grown by pulsed laser deposition1997In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 305, no 1-2, p. 243-247Article in journal (Refereed)
    Abstract [en]

    Highly oriented thin films of alpha-alumina have been grown by pulsed laser deposition on Si(lll). The influence of the substrate temperature on the film growth was studied by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (MID). Ablation at temperatures between room temperature and 850 degrees C gave rise to incorporated crystalline aluminium (Al), while the stoichiometric and highly oriented alpha-Al2O3 films were obtained only at 850 degrees C. The XRD rocking curve measurements of the ablated films showed the full-width-at-half-maximum (FWHM) Of 0.2 degrees. Further annealing at 1000 degrees C in air for 26 h slightly improved out-of-plane orientation. (C) 1997 Elsevier Science S.A.

  • 29.
    Huang, Dan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Persson, Clas
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Band gap change induced by defect complexes in Cu2ZnSnS42013In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 535, p. 265-269Article in journal (Refereed)
    Abstract [en]

    Understanding the impact on the electronic and optical properties of kesterite Cu2ZnSn(S,Se)(4) due to the presence of native defects is crucial for designing and manufacturing efficient solar cells. In this work, we complement earlier published theoretical studies by investigating the change in the Cu2ZnSnS4 band gap energy induced by the dominating isovalent (Zn (Cu) + Cu-Zn) and (Zn-Cu + V-Cu) defect complexes and the corresponding larger [(Zn-Cu + Cu-Zn)+(Zn-Cu + V-Cu)] complex. The study is based on the generalized gradient approximation with corrections for on-site Coulomb interactions (GGA + U) and the Heyd-Scuseria-Ernzerh hybrid functional method (HSE06) within the first-principles density functional theory. We find that (Zn-Cu + Cu-Zn) and (Zn-Cu + V-Cu) affect the band gap energies in an opposite way: (Zn-Cu + Cu-Zn) decreases the gap whereas (Zn-Cu + V-Cu) increases the gap. However, there is a strong correlation between these two defect complexes. The presence of the Cu-poor (Zn-Cu + V-Cu) defect complex lowers the formation energy of the antisite (Zn-Cu + Cu-Zn) defect complex in close configuration, and vice versa. Thereby, and considering the opposite effect on the band gap for (Zn-Cu + Cu-Zn) and (Zn-Cu + V-Cu), our results indicate that the band gap energy will be compensated and stabilized in Cu-poor Cu2ZnSnS4. We discuss the underlying mechanisms behind the band gap physics of the considered isovalent defect complexes.

  • 30. Hummelgard, Christine
    et al.
    Gustavsson, John
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Cornell, Ann
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Olin, Hakan
    Backstrom, Joakim
    Spin coated titanium-ruthenium oxide thin films2013In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 536, p. 74-80Article in journal (Refereed)
    Abstract [en]

    Substrates of different roughness spin coated with Ti0.7Ru0.3O2 films have been evaluated as model system for fundamental studies of the industrially and scientifically interesting (Ti, Ru)O-2 based electrodes. The approach allowed for much more accurate control over the material synthesis than the traditionally used brush-, dip-, or spray-coating, on titanium-metal substrates. It moreover yielded well-defined samples suitable for basic studies of the surface properties that are of fundamental importance for understanding the electrochemical functionality of the electrode. We have compared the films on silicon substrates to films prepared by spin coating the same material on titanium-metal substrates. Samples have been characterized using atomic force microscopy (AFM), X-ray diffraction, scanning electronmicroscopy (SEM), and cyclic voltammetry. The samples displayed a uniformity of the films appropriate for AFM characterization. The smoother the substrate the less cracks in the coating. Using easily broken silicon wafers as substrate, a straightforward sample preparation technique was demonstrated for cross-section SEM. In addition, using high spinning velocities we have deposited the oxide films directly on silicon-nitride grids, thin enough to allow for studies with transmission electron microscopy without further sample preparation.

  • 31.
    Hållstedt, Julius.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Hellström, Per-Erik
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Radamson, Henry H.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Sidewall transfer lithography for reliable fabrication of nanowires and deca-nanometer MOSFETs2008In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 517, no 1, p. 117-120Article in journal (Refereed)
    Abstract [en]

    Today MOSFET devices are approaching gate lengths on the order of 10 nm. This sets extreme demands on gate patterning technique. This paper describes a side wall transfer lithography technique to pattern decananomeer MOSFETs or nanowires. A correlated line edge roughness leading to a very low line width roughness was demonstrated for the patterned gates. Moreover, the technology was shown to be robust and reproducible with high yield and uniformity suitable for mass fabrication. Finally, integration of the sidewall transfer lithography was performed in various novel MOSFET devices.

  • 32.
    Johansson, Petter
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Condensed Matter Theory.
    Khartsev, Sergiy
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Grishin, Alexander M.
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    Comparison of Bi3Fe5O12 film giant Faraday rotators grown on (111) and (001) Gd3Ga5O12 single crystals2006In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 2, p. 477-480Article in journal (Refereed)
    Abstract [en]

    Bismuth iron garnet (Bi3Fe5O12, BIG) epitaxial thin films were grown on single crystal (Gd3Ga5O12, GGG) (111) and (001) substrates by rf-magnetron sputtering technique. Processing parameters have been optimized to obtain high deposition rate (2.74 mu m/h) and the surface rms roughness less than 10 nm. X-ray diffraction reveals films epitaxial quality: exclusive (111) or (00 1) orientation with narrow rocking curves and strong in-plane texture. Films possess low optical loss and magneto-optical Faraday rotation (FR) as high as 5 deg/mu m at 677 nm wavelength. Comparative analysis of films grown on (111) and (001) substrates clearly shows significant superiority of BIG/GGG(001) film. For this film, the coercive field similar to 100 Oe appears to be 2.5 times lower while the optical transmission to be 10% higher than that for BIG/GGG(111) film. Enhanced magneto-optical performance of BIG/GGG(001) films relies upon better accommodation of the film-to-substrate mismatch strain through the tetragonal BIG lattice distortions compared to the rhombohedral one in BIG/GGG(111) films.

  • 33. Karlsson, Ulf O
    Preface: Proceedings of the Eighth International Conference on Atomically Controlled Surfaces, Interfaces and Nanostructures and the Thirteenth International Congress on Thin Films, Stockholm, Sweden, June 20-23, 20052006In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 2, p. 381-Article in journal (Refereed)
  • 34.
    Kim, Jang-Yong
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Grishin, Alexander M.
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    AgTaO3 and AgNbO3 thin films by pulsed laser deposition2006In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 2, p. 615-618Article in journal (Refereed)
    Abstract [en]

    Silver tantalate AgTaO3 (ATO) and silver niobate AgNbO3 (ANO) films have been grown on to the LaAlO3 (001) and sapphire Al2O3 (0112, r-cut) single crystals by pulsed laser deposition technique from stoichiometric ATO and ANO targets. X-ray diffraction study revealed epitaxial quality of ATO and ANO films on the LaAlO3 (00 1) Whereas on the sapphire r-cut substrate they are preferential (I 10) and (00 1) oriented. To characterize microwave films properties in the range from I to 40 GHz, coplanar line interdigital capacitors were fabricated by photolithography and lift-off technique. ANO film capacitors show superior properties: frequency dispersion was as low as 13%, voltage tunability (40 V, 200 kV/ cm) was about 4.6% at 20 GHz, loss tangent similar to 0.106 at 20 GHz, K-factor-tunability/tan delta from 49% @ 10 GHz to 33% at 40 GHz.

  • 35.
    Kim, Jang-Yong
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Grishin, Alexander M.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Niobate-tantalate thin films microwave varactors2006In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Thin solid films, Vol. 515, no 2, p. 619-622Article in journal (Refereed)
    Abstract [en]

    We present comparative characteristics of microwave variable capacitors (varactors) fabricated on Na0.5K0.5NbO3 (NKN), AgTa0.5Nb0.5O3 (ATN) and Ba0.5Sr0.5TiO3 (BST) ferroclectric films sintered by pulsed laser deposition technique. Two port 2 mu m finger gap coplanar waveguide interdigital capacitive (CPWIDC) structures were defined on ferroelectric films surface by a standard lift off technique. Results of the microwave on-wafer tests performed in frequency range 1 to 40 GHz have been examined with a de-embedding technique to extract device characteristics from the measured S-parameters. The frequency dispersion of capacitance was 37%, 4.3%, and 17%; the voltage tunability (200 kV/cm) 22%, 4.7%, and 22% at 20 GHz; loss tangent similar to 0.23, 0.068, and 0.137 at 20 GHz for NKN/Nd:YAlO3, ATN/Al2O3, and BST/Al2O3 films capacitors.

  • 36.
    Kim, Joo-Hyung
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Grishin, Alexander M.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wet and dry etching of La-0.67(Sr,Ca)(0.33)MnO3 films on Si.2006In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 2, p. 587-590Article in journal (Refereed)
    Abstract [en]

    We report etching processes of epitaxial La-0.67(Sr,Ca)(0.33)MnO3 (LSCMO) colossal magnetoresistive (CMR) films grown on Bi4Ti3O12/CeO2/YSZ oxide-buffered Si using buffered HF (BHF), potassium hydroxide (KOH) and Ar ion beam etching (IBE) methods. LSCMO films demonstrate high resistivity against the KOH etchant whereas 22 nm/min etching rate was obtained in the BHF with high selectivity over photoresist and Si. Compared to 24 nm/min for Si, Ar IBE yields 16 nni/min etching rate for the LSCMO film and the oxide-buffer layers.

  • 37.
    Kim, Joo-Hyung
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Grishin, Alexander M.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Radamson, Henry
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Properties of La0.75Sr0.25MnO3 films grown on Si substrate with Si1-xGex and Si1-yCy buffer layers2006In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 2, p. 411-415Article in journal (Refereed)
    Abstract [en]

    The structural and electrical properties of La0.75Sr0.25MnO3 (LSMO) film on Bi4Ti3O12 (BTO)/CeO2/YSZ buffered Si1-xGex/Si(0.05

  • 38. Kolahdouz, M.
    et al.
    Ghandi, R.
    Hållstedt, Julius.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Osling, M.
    Wise, R.
    Wejtmans, Hans
    Radamson, Henry H.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    The influence of Si coverage in a chip on layer profile of selectively grown Si1-xGex layers using RPCVD technique2008In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 517, no 1, p. 257-258Article in journal (Refereed)
    Abstract [en]

    The influence of chip layout (Si coverage and geometry) on the pattern dependency of selective epitaxy of SiGe layers has been investigated. The variation of Ge content and the growth rate have been investigated from a chip-to-chip (local effect) or wafer-to-wafer. The results are described by transport and diffusion of the reactant molecules over the chips during epitaxy. Our investigations are focused on the origin of pattern dependency of the deposition and also propose methods to control this growth behavior.

  • 39. Kudryavtsev, Y. V.
    et al.
    Melnyk, A. K.
    Kravets, A. F.
    Trachevskyi, V. V.
    Korenivski, Vladislav
    KTH, School of Engineering Sciences (SCI), Applied Physics, Nanostructure Physics.
    Ferromagnetic resonance evidence of spinodal decomposition of Ni-x Cu1-x (0.5 < x < 1) alloy films2016In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 603, p. 424-427Article in journal (Refereed)
    Abstract [en]

    Films of diluted ferromagnetic (FM) Ni-x Cu1 - x alloys with 0.5 < x < 1 of about 80 nm in thickness were deposited at room temperature on glass-ceramic substrates using electron-beam co-deposition from Cu and Ni sources. The temperature dependence of the ferromagnetic resonance (FMR) spectra was investigated in the 140 < T < 500 K temperature range. The FMR spectra for films of composition 0.75 <= x <= 0.89 show two absorption peaks, which can be ascribed to a formation of two different FM phases as a result of phase separation in the alloy. The observed unusual temperature dependence of the resonance magnetic fields is interpreted as potentially magnetostrictive in nature. The results are discussed and compared to those for similar Ni-Cu films obtained using magnetron sputtering.

  • 40.
    Kumar, Mukesh
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Zhao, Hanyue
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Persson, Clas
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Cation vacancies in the alloy compounds of Cu2ZnSn(S1-xSex)(4) and CuIn(S1-xSex)(2)2013In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 535, p. 318-321Article in journal (Refereed)
    Abstract [en]

    The present work analyzes theoretically the formation energy of the cation vacancies V-Cu, V-In, V-Zn, and V-Sn in Cu2ZnSn(S1-xSex)(4) and CuIn(S1-xSex)(2) alloy compounds. An atomistic first-principles study is carried out by employing a generalized gradient approximation and a hybrid functional approach within the density functional theory, using the supercell approach to model the alloy compositions x = 0.00, 0.25, 0.50, 0.75, and 1.00. We find that the Cu vacancy is the most dominant cation vacancy with the lowest formation energy Delta H-f. The formation energy of V-Cu is very similar in both types of alloy compounds, while the formation energy of V-In in CuIn(S1-xSex)(2) is roughly the average value of the formation energies of V-Zn and V-Sn in Cu2ZnSn(S1-xSex)(4). Moreover, we find that the vacancy formation energies are larger in the S-rich compounds compared with the corresponding vacancies in the Se-rich compounds. The results suggest that the concentration of especially V-Cu can, to some extent, be controlled by anion alloying.

  • 41.
    Laurell, Fredrik
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Arvidsson, G.
    Jaskorzynska, B.
    Non-linearoptical wavelength conversion in Ti:LiNbO3 waveguides1986In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731Article in journal (Refereed)
  • 42. Liang, H. L.
    et al.
    Mei, Z. X.
    Liu, Z. L.
    Guo, Y.
    Azarov, A. Yu.
    Kuznetsov, A. Yu.
    Hallén, Anders
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Du, X. L.
    Growth of single-phase Mg0.3Zn0.7O films suitable for solar-blind optical devices on RS-MgO substrates2012In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 520, no 6, p. 1705-1708Article in journal (Refereed)
    Abstract [en]

    Single-phase rock-salt Mg0.3Zn0.7O film was fabricated on MgO (100) substrate by radio-frequency plasma assisted molecular beam epitaxy. A smooth surface was observed by in-situ reflection high-energy electron diffraction and ex-situ atomic force microscopy. X-ray diffraction characterization demonstrated a high-quality single-phase structure with highly (200) orientation and cube-on-cube epitaxial relationship. Zn fraction in the single-phase rock-salt Mg0.3Zn0.7O film was determined by Rutherford backscattering spectrometry. Optical property of the film was investigated by reflectance spectroscopy, which indicated a solar-blind band gap of 255.5 nm. The reason why Zn solubility limit is greatly enhanced in non-polar (100) film compared with (111) polar epilayer is tentatively discussed in this work, suggesting MgO (100) is more suitable for the synthesis of single-phase rock-salt MgZnO with high Zn content towards solar-blind opto-device applications.

  • 43. Lu, J.
    et al.
    Hugosson, Håkan Wilhelm
    Eriksson, O.
    Nordstrom, L.
    Jansson, U.
    Chemical vapour deposition of molybdenum carbides: aspects of phase stability2000In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 370, no 02-jan, p. 203-212Article in journal (Refereed)
    Abstract [en]

    Thin films of different molybdenum carbides (delta-MoC1-x, gamma'-MoC1-x and Mo2C) have been deposited from a gas mixture of MoCl5/H-2/C2H4 at 800 degrees C by CVD. The H-2 content in the vapour has a strong influence on the phase composition and microstructure. Typically, high H-2 contents lead to the formation of nanocrystalline delta-MoC1-x films while coarse-grained gamma'-MoC1-x, is formed with an H-2-free gas mixture. This phase has previously only been synthesized by carburization of Mo in a CO atmosphere and it has therefore been considered as an oxycarbide phase stabilized by the presence of oxygen in the lattice. Our results, however, show that gamma'-MoC1-x films containing only trace amounts of oxygen can be deposited by CVD. Stability calculations using a FP-LMTO method confirmed that the gamma'-MoC1-x phase is stabilized by oxygen but that the difference in energy between e.g. delta-MoC0.75 and oxygen-free gamma'-MoC0.75 is Small enough to allow the synthesis of the latter phase in the absence of kinetic constraints. Annealing experiments of metastable delta-MoC1-x and gamma'-MoC1-x films showed two different reaction products suggesting that kinetic effects play an important role in the decomposition of these phases.

  • 44. Malmgren, Christine
    et al.
    Eriksson, Annika K.
    Cornell, Ann
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Bäckström, Joakim
    Eriksson, Sten
    Olin, Håkan
    Nanocrystallinity in RuO2 coatings-Influence of precursor and preparation temperature2010In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 518, no 14, p. 3615-3618Article in journal (Refereed)
    Abstract [en]

    The effects of precursor and calcination temperature on the nano morphology of ruthenium dioxide on titanium, prepared from thermal decomposition of aqueous salt solutions were investigated. Transmission electron microscopy. X-ray diffraction, gas porosimetry and cyclic voltammetry showed that lower calcination temperature yielded smaller crystallites. The crystallites were between 6 and 22 nm in diameter. When using ruthenium nitrosyl nitrate the firing temperature had a large impact on the grain size, but for chloride there was only a minor effect in the temperature range 350-550 degrees C.

  • 45.
    Moeen, Mahdi
    et al.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Kolahdouz, Mohammad Reza
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits. University of Tehran, Iran.
    Salemi, Arash
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Radamson, Henry
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Improved designs of Si-based quantum wells and Schottky diodes for IR detection2016In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 613, p. 19-23Article in journal (Refereed)
    Abstract [en]

    Novel structures of intrinsic or carbon-doped multi quantum wells (MQWs) and intrinsic or carbon-doped Si Schottky diodes (SD), individually or in combination, have been manufactured to detect the infrared (IR) radiation. The carbon concentration in the structures was 5 × 1020 cm− 3 and the MQWs are located in the active part of the IR detector. A Schottky diode was designed and formed as one of the contacts (based on NiSi(C)/TiW) to MQWs where on the other side the structure had an Ohmic contact. The thermal response of the detectors is expressed in terms of temperature coefficient of resistance (TCR) and the quality of the electrical signal is quantified by the signal-to-noise ratio. The noise measurements provide the K1/f parameter which is obtained from the power spectrum density. An excellent value of TCR = − 6%/K and K1/f = 4.7 × 10− 14 was measured for the detectors which consist of the MQWs in series with the SD. These outstanding electrical results indicate a good opportunity to manufacture low cost Si-based IR detectors in the near future.

  • 46. Norouzi, M.
    et al.
    Kolahdouz, M.
    Ebrahimi, P.
    Ganjian, M.
    Soleimanzadeh, R.
    Narimani, K.
    Radamson, Henry
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Thermoelectric energy harvesting using array of vertically aligned Al-doped ZnO nanorods2016In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 619, p. 41-47Article in journal (Refereed)
    Abstract [en]

    Renewable energy harvesting is an innovative research area which has attracted a great deal of efforts to find a substitute for fossil sources. This work presents processing and characterization of thermoelectric device (one leg of the nanogenerator) made of aluminum-doped zinc oxide (ZnO) nanorods on the glass substrate. The effect of aluminum-doping on the Seebeck coefficient as an important figure-of-merit for thermoelectric performance has been extensively studied. The electrical characterization was performed to examine the quality of the nanorods' contacts. For 1% Al-doped ZnO nanorods on the silicon substrate, open circuit voltage of 0.28 mV and S.C. current of 3.5 mu A were obtained. In these measurements, a constant temperature difference of 1 K between the top and bottom side of the nanorods was implemented. The Seebeck coefficient was found to be increased proportionally with the doping concentration.

  • 47.
    Persson, Clas
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Impurity induced band-gap narrowing in p-type CuIn1-xGax(S,Se)(2)2009In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 517, no 7, p. 2374-2379Article in journal (Refereed)
    Abstract [en]

    Green's functions modelling of the impurity induced effects in p-type CuIn1-xGaxS2 and CuIn1-xGaxSe2 (x = 0.0, 0.5, and 1.0) reveals that: (i) the critical active acceptor concentration for the metal non-metal transition occurs at Nc approximate to 10(17)-10(18) cm(-3) for impurities with ionization energy of E-A approximate to 30-60 meV. (ii) For acceptor concentrations N-A>N-C, the hole gas of the metallic phase affects the band-edge energies and narrows the energy gap E-g=E-g(0)=Delta E-g. The energy shift of the valence-band maximum Delta E-v1 is roughly twice as large as the shift of the conduction-band minimum Delta E-c1. (iii) Delta E-v1 depends strongly on the non-parabolicity of the valence bands. (iv) Sulfur based compounds and Ga-rich alloys have the largest shifts of their band edges. (v) A high active acceptor concentrations of N-A = 10(20) cm(-3) implies a band-gap narrowing in the order of Delta E-g approximate to 0.2 eV, thus E-g=E-g(0)-0.2 eV, and an optical band gap of E-g(opt)approximate to E-g(0)-0.1 eV.

  • 48.
    Persson, Stefan
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Isheden, Christian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Jarmar, Tobias
    Uppsala University, Ångström Laboratory, Materials Science.
    Zhang, Shi-Li
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lateral growth and three-dimensional effects in contacts between NiSi0.82Ge0.18 and p(+)-Si0.82Ge0.182005In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 489, no 1-2, p. 159-163Article in journal (Refereed)
    Abstract [en]

    Electrical contacts of NiSi0.82Ge0.18 to P+-Si0.82Ge0.18 were fabricated and characterised. Lateral growth of the NiSi0.82Ge0.18 under SiO2 isolation was observed. A three-dimensional model was employed to extract the contact resistivity by considering both the lateral growth and the presence of a recessed NiSi0.82Ge0.18 step into the Si0.82Ge0.18. The contact resistivity extracted was 5.0 x 10(-8) and 1.4 x 10(-7) Omega cm(2) for small contacts of circular geometry and large contacts of square shape, respectively. Possible causes responsible for this 3-fold difference in contact resistivity were discussed. An underestimate of the contact resistivity by 35% was found if a two-dimensional model was used without taking into account the complex interface morphology.

  • 49. Platzer-Bjorkman, C.
    et al.
    Jani, S.
    Westlinder, J.
    Linnarsson, Margareta K.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Scragg, J.
    Edoff, M.
    Diffusion of Fe and Na in co-evaporated Cu(In, Ga) Se-2 devices on steel substrates2013In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 535, p. 188-192Article in journal (Refereed)
    Abstract [en]

    In this work we study impurity diffusion into Cu(In, Ga) Se-2 from stainless steel substrates with and without Cr diffusion barriers using secondary ion mass spectrometry. For these substrate configurations we compare cases with and without adding NaF as a sodium precursor. A clear increase in impurity diffusion from the substrate is observed for samples with NaF. Devices made using our micro pilot line show the expected correlation between Fe content, Na content and efficiency, but the highest device efficiency obtained for steel substrates is still slightly below that of the glass substrate reference. We discuss reasons for the observed device performance.

  • 50. Qi, B.
    et al.
    Agnarsson, B.
    Olafsson, S.
    Gislason, H. P.
    Göthelid, Mats
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Room temperature deposition of self-assembled Al nanoclusters on stepped sapphire (0001) surface and subsequent nitridation2011In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 520, no 1, p. 64-73Article in journal (Refereed)
    Abstract [en]

    Self-assembled growth and nitridation of ultrathin Al nanoclusters on a stepped sapphire (0001) surface were studied by high-resolution X-ray photoemission spectroscopy, atomic force microscopy and low-energy electron diffraction (LEED). Upon room temperature deposition, in the coverage range of similar to 0.79 to 2.3 monolayer (ML), Al nanoclusters were uniformly nucleated over the entire surface of defect-free atomically smooth terraces as well as step edges. Subsequent nitridation at elevated temperatures by ammonia did not alter the morphology of the nanoclusters. The global morphology of the stepped sapphire (0001) surface such as terrace width, step height and facet orientation had no obvious influence on the nucleation morphology of the nanoclusters in the given Al coverage range. However, local structural defects at the joints of short facets and step edges played a noticeable role on the local morphology of the nanoclusters and subsequently the nitridation chemistry. The Al nanoclusters were uniformly nitridated from surface and downwards through the 3D structures. The LEED pattern indicated a certain degree of crystallinity on the nitridated surface at a nominal Al coverage less than 2 ML, whereas at 2.3 ML Al coverage, the nitridated surface became amorphous. Thus there is a critical coverage for good surface order.

12 1 - 50 of 70
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