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  • 1. Azarov, A. Yu.
    et al.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Hallen, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Aggerstam, T.
    Dopant distribution in high fluence Fe implanted GaN2008In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 104, no 5, p. 053509-Article in journal (Refereed)
    Abstract [en]

    Undoped wurtzite GaN epilayers implanted at room temperature with 50-325 keV Fe+ ions in the fluence range of 10(15)-10(17) ions/cm(2) are studied by a combination of Rutherford backscattering/channeling spectrometry and time-of-flight elastic recoil detection analysis. The results show an enhanced Fe concentration close to the surface for high ion fluences (>1 X 10(16) cm(-2)), which increases with the ion fluence. Annealing at 800 degrees C for 30 min has a negligible effect on the Fe distribution in the material bulk, but further increases the Fe concentration near the surface. Our findings can be understood by radiation enhanced diffusion during ion implantation and an increased Fe diffusivity in the near surface region with distorted stoichiometry, or formation of secondary phases and precipitates for the highest doses. The simulation shows that, if enhanced diffusion is the reason for Fe buildup at the surface, both radiation enhanced diffusion and the thermal diffusion of Fe atoms near the surface, need to be at least five times larger than ordinary bulk diffusion to explain the increased Fe surface concentration.

  • 2. Azarov, Yu A
    et al.
    Hallén, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Aggerstam, T
    Lourdudoss, S
    High dose Fe implantation of GaN: damage build-up and dopant redistribution2008In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 100, no 4, p. 042036-Article in journal (Refereed)
  • 3.
    Boström, Tobias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Jensen, J
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Westin, G
    Wäckelgård, Ewa
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Proceedings of Eurosun 20062006Conference paper (Refereed)
  • 4.
    Boström, Tobias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Jensen, J
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Westin, Gunnar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Wäckelgård, Ewa
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Accelerated ageing tests of optimized solution chemically derived selective solar thermal absorbers2006Conference paper (Refereed)
  • 5.
    Boström, Tobias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Valizadeh, Sima
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Westin, Gunnar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Wäckelgård, Ewa
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    ERDA of Ni-Al2O3/SiO2 solar thermal selective absorbers2008In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 92, no 10, p. 1177-1182Article in journal (Refereed)
    Abstract [en]

    Thin film materials for the use in solar thermal absorbers have been investigated using time-of-flight energy elastic recoil detection analysis (ERDA). The ERDA measurements proved to be very efficient in detecting the elemental depth composition of a selective solar absorber. The three-layer absorber is composed of an 80% nickel-20% alumina film at the base, a 40% nickel-60% alumina layer in the middle and finally an AR film of silica or hybrid-silica film at the top. The difference between solution volume percent and actual volume percent could be investigated when studying individual nickel-alumina films with varying ratios coated on glass substrates. The result showed that there was a maximum difference of 3% between the calculated solution volume percent and the actual volume percentages in the solid films. The ERDA measurements also indicate that about 15% of the nickel found in the nickel-alumina composite films is bound in the form of NiO.

  • 6. Intarasiri, Saweat
    et al.
    Dangtip, S.
    Hallén, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Yu, L.D.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Singkarat, S.
    Activation energy of the growth of ion-beam-synthesized nano-crystalline 3C-SiC2007In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 257, no 1-2, p. 195-198Article in journal (Refereed)
    Abstract [en]

    In this experiment, carbon ions at 40 keV were implanted into (10 0) high-purity p-type silicon wafers at 400 degrees C to a fluence of 6.5 x 10(17) ions/cm(2). Subsequent thermal annealing of the implanted samples was performed in a vacuum furnace at 800-1000 degrees C. Glancing incidence X-ray diffraction (GIXRD) was used to characterize the crystalline quality and estimate the grain size of nano-crystalline 3C-SiC. Activation energy for the growth of 3C-SiC was evaluated following the annealing behaviour of the GIXRD-characteristic 3C-SiC (111) peaks. It was found that the 3C-SiC was directly formed during ion implantation at this substrate temperature and the activation energy of the process was about 0.05 eV. Such a low energy was explained in terms of ion beam induced precipitate formation.

  • 7.
    Intarasiri, Saweat
    et al.
    Institute for Science and Technology Research and Development, Chiang Mai University.
    Hallén, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Lu, Jun
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Bertilsson, K.
    Mittuniversitetet.
    Wolborski, M.
    KTH.
    Singkarat, S.
    FNRF, Department of Physics, Faculty of Science, Chiang Mai University.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Crystalline quality of 3C-SiC formed by high-fluence C+-implanted Si2007In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 253, no 11, p. 4836-4842Article in journal (Refereed)
    Abstract [en]

    Carbon ions at 40 keV were implanted into (1 0 0) high-purity p-type silicon wafers at 400 °C to a fluence of 6.5 × 1017 ions/cm2. Subsequent thermal annealing of the implanted samples was performed in a diffusion furnace at atmospheric pressure with inert nitrogen ambient at 1100 °C. Time-of-flight energy elastic recoil detection analysis (ToF-E ERDA) was used to investigate depth distributions of the implanted ions. Infrared transmittance (IR) and Raman scattering measurements were used to characterize the formation of SiC in the implanted Si substrate. X-ray diffraction analysis (XRD) was used to characterize the crystalline quality in the surface layer of the sample. The formation of 3C-SiC and its crystalline structure obtained from the above mentioned techniques was finally confirmed by transmission electron microscopy (TEM). The results show that 3C-SiC is directly formed during implantation, and that the subsequent high-temperature annealing enhances the quality of the poly-crystalline SiC.

  • 8. Intarasiri, Saweat
    et al.
    Yu, L.D.
    Singkarat, S.
    Hallén, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Lu, Jun
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Effects of low-fluence swift iodine ion bombardment on the crystallization of ion-beam-synthesized silicon carbide2007In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 101, no 8, p. 084311-Article in journal (Refereed)
    Abstract [en]

    Ion beam synthesis using high-fluence carbon ion implantation in silicon in combination with subsequent or in situ thermal annealing has been shown to be able to form nanocrystalline cubic SiC (3C-SiC) layers in silicon. In this study, a silicon carbide layer was synthesized by 40-keV C 12 + implantation of a p -type (100) Si wafer at a fluence of 6.5× 1017 ions cm2 at an elevated temperature. The existence of the implanted carbon in Si substrate was investigated by time-of-flight energy elastic recoil detection analysis. The SiC layer was subsequently irradiated by 10-30 MeV I 127 ions to a very low fluence of 1012 ions cm2 at temperatures from 80 to 800 °C to study the effect on the crystallization of the SiC layer. Infrared spectroscopy and Raman scattering measurement were used to monitor the formation of SiC and detailed information about the SiC film properties was obtained by analyzing the peak shape of the Si-C stretching mode absorption. The change in crystallinity of the synthesized layer was probed by glancing incidence x-ray diffraction measurement and transmission electron microscopy was also used to confirm the results and to model the crystallization process. The results from all these measurements showed in a coherent way that the synthesized structure was a polycrystalline layer with nanometer sized SiC crystals buried in a-Si matrix. The crystallinity of the SiC layer was enhanced by the low-fluence swift heavy ion bombardment and also favored by higher energy, higher fluence, and higher substrate temperature. It is suggested that electronic stopping plays a dominant role in the enhancement.

  • 9. Jaafar, M.
    et al.
    Asenjo, A.
    Sanz, R.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Vázquez, M.
    Schäfer, R.
    Magnetic anisotropy changes induced by high energy ion bombardment2006Conference paper (Other academic)
  • 10. Jaafar, M.
    et al.
    Sanz, R.
    Vazquez, M.
    Asenjo, A.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Flohrer, S.
    Schäfer, R.
    FePt thin film irradiated with high energy ions2007In: Physica status solidi. A, Applied research, ISSN 0031-8965, E-ISSN 1521-396X, Vol. 204, no 6, p. 1724-1730Article in journal (Refereed)
    Abstract [en]

    The changes in structural and magnetic properties of FePt thin films due to the irradiation with high energy ions (Br7+ and Cl2+) were studied. From the hysteresis loops dominating in-plane anisotropy is derived, however, the samples present a minor out-of-plane component. The structure and the magnetic properties of the films can be tuned by selecting the appropriate irradiation parameters (different ions, energies and fluencies). For the irradiation parameters used in this study an in-plane anisotropy is favoured. Irradiation with Br7+ seems to induce minor changes in the structural ordering of the thin films, whereas the Cl2+ ions promote the amorphization of the surface of the films. In addition, a magnetic thin film pattemed at the micrometer scale was obtained after irradiation through a micrometric mask.

  • 11.
    Jensen, Jens
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Experimental Physics. Avdelningen för jonfysik.
    Johansson, A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Experimental Physics.
    Skupinski, Marek
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Experimental Physics. Materialvetenskap.
    Surpi, Alessandro
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Experimental Physics. Elektronmikroskopi och Nanoteknologi.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Materialvetenskap.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Experimental Physics. Jonfysik.
    Nanostructuring by heavy ion beam-based lithography2007Conference paper (Refereed)
  • 12.
    Jensen, Jens
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Linnarsson, M.
    Aggerstam, T.
    Lourdudoss, S.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Hallén, A.
    Fe doping of GaN by ion implantation2006Conference paper (Other (popular science, discussion, etc.))
  • 13.
    Jensen, Jens
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Possnert, Göran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Razpet, Alenka
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Skupinski, Marek
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Materialvetenskap.
    Ion track formation in thin films of amorphous SiO2 using energies below 1 MeV/u2005In: Presented at the 6th International Symposium on Swift Heavy Ions in Matter (SHIM-2005) Aschaffenburg, Germany., 2005Conference paper (Other scientific)
  • 14.
    Jensen, Jens
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Sanz, Ruy
    Skupinski, Marek
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Hernandez-Velez, M.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Swift Heavy Ion Beam-Based Nanopatterning Using Self-Assembled Masks2007In: Materials Research Society, Symposium Proceedings Volume 1020: Ion-Beam-Based Nanofabrication, Warrendale, Pa: Materials Research Society , 2007, p. 55-Conference paper (Refereed)
    Abstract [en]

    Swift heavy ion beam-based lithography using masks of self-assembled materials has been applied for transferring well-ordered micro- and nanopatterns to rutile TiO2 single crystals. As the induced damage has a high etching selectivity the patterns can be developed in HF with very high contrast. Here we present resulting patterns when using a mask of self-ordered silica spheres. Since the obtained structures are replicas of the mass distribution of the applied mask, the shape and size of resulting structures depend on the geometric configuration of the silica sphere layers. In addition, the resulting pattern can be tuned by varying the applied ion energy and fluence. Direct modifications of the optical properties of TiO2 in a well-defined pattern are also presented.

  • 15. Kamalou, O.
    et al.
    Zettergren, H.
    Schmidt, H.T.
    Cederquist, H.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Tomita, S.
    Hvelplund, P.
    Manil, B.
    Rangama, J.
    Huber, B.A.
    Fullerene Collisions and Clusters of Fullerenes2006In: International Journal of Mass Spectrometry, Vol. 252, p. 117-Article in journal (Refereed)
  • 16. Khalfaoui, N.
    et al.
    Rotaru, C. C.
    Bouffard, S.
    Toulemonde, M.
    Stoquert, J. P.
    Haas, F.
    Trautmann, C.
    Jensen, Jens
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Dunlop, A.
    Characterization of swift heavy ion tracks in CaF2 by scanning force and transmission electron microscopy2005In: Nucl. Inst. Meth., Vol. B 240, p. 819-Article in journal (Refereed)
  • 17. Manil, B.
    et al.
    Boduch, P.
    Cassimi, A.
    Kamalou, O.
    Maunoury, L.
    Jensen, Jens
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Zettergren, H.
    Collision induced fragmentation of fullerene clusters2005In: Int. Journ. Modern Physics, Vol. B 19, p. 2345-2352Article in journal (Refereed)
  • 18. Manil, B.
    et al.
    Maonoury, L.
    Jensen, Jens
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Cederquist, H.
    Schmidt, H.T.
    Zettergren, H.
    Hvelplund, P.
    Tomita, S.
    Huber, B.A.
    Fragmentation of chaged fullerene dimers:: Kinetic energy release2005In: Nucl. Instr. Meth., Vol. B 235, p. 419-Article in journal (Refereed)
  • 19.
    Martin, David
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Enlund, Johannes
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Kappertz, Oliver
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Comparing XPS and ToF-ERDA measurement of high-k dielectric materials2007Conference paper (Refereed)
  • 20.
    Martin, David
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Enlund, Johannes
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Kappertz, Oliver
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Comparing XPS and ToF-ERDA measurement of high-k dielectric materials2008In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 100, no 1, p. 012036-Article in journal (Refereed)
  • 21.
    Martin, David
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Enlund, Johannes
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Kappertz, Oliver
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Compositional characterization of high-k dielectric material via XPS and ToF-ERDA2006Conference paper (Other (popular science, discussion, etc.))
  • 22. Maunoury, L.
    et al.
    Pacquet, J. Y.
    Pedersen, U. V.
    Jensen, Jens
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Tomita, S.
    Zettergren, H.
    Gustavo, F.
    Ion beams of carbon clusters and multiply charged fullerenes produced with electron cyclotron resonance ion sources2005In: Rev. Sci. Instrum., Vol. 76Article in journal (Refereed)
  • 23.
    Petersson, Per
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Bergsåker, Henric
    Hallén, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Mapping of hydrogen isotopes with a scanning nuclear microprobe2008In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 266, no 10, p. 2429-2432Article in journal (Refereed)
    Abstract [en]

    Elastic recoil detection analysis using heavy ions with a scanning nuclear microprobe was applied to determine the content of hydrogen isotopes in carbon material facing fusion plasma in the JET fusion reactor. The hydrogen and deuterium concentrations in re-deposited material were obtained by mapping a cross sectional cut of a wall sample. De-trapping and hydrogen release caused by the primary ion beam were investigated. For both the deuterium and hydrogen concentration a drop of similar to 75% was observed from an extrapolated initial value to a final steady state region. A procedure was used to determine the initial concentration. In this way a mapping of the initial deuterium concentration could be obtained.

  • 24.
    Petersson, Per
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Hallén, Anders
    Department of Microelectronics and IT, Royal Institute of Technology, Sweden .
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Measurement of hydrogen isotopes by nuclear microprobe2008In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 100, no 6, p. 062029-Article in journal (Refereed)
  • 25. Sanz, R
    et al.
    Hernández-Vélez, M
    Kubart, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Martin, David
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Magnetic behaviour of Fe implanted TiO2 thin films2008In: Book of Abstracts, Madrid, Spain, 2008Conference paper (Refereed)
  • 26. Sanz, R.
    et al.
    Jaafar, M.
    Asenjo, A.
    Rosa, W.O.
    Hernandez-Vélez, M.
    Badini-Confalonieri, G.A.
    Vázquez, M.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Effects on the Structural and Magnetic Properties of Amorphous Ribbons caused by 4 MeV Cl^2+ ion irradiations2006Conference paper (Other academic)
  • 27. Sanz, R
    et al.
    Jaafar, M
    Hernández-Vélez, M
    Asenjo, A
    Vásquez, M
    Surpi, A
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Magnetic patterns induced by restricted ion irradiation through different masks2008In: Book of Abstracts, Forth Worth, USA, 2008Conference paper (Refereed)
  • 28.
    Sanz, R.
    et al.
    Instituto de Ciencia de Materiales de Madrid.
    Jaafar, M.
    Instituto de Ciencia de Materiales de Madrid.
    Rosa, W.O.
    Instituto de Ciencia de Materiales de Madrid.
    Badini-Confalonieri, G.
    Instituto de Ciencia de Materiales de Madrid.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Hernandez-Vélez, M.
    Instituto de Ciencia de Materiales de Madrid.
    Vázquez, M.
    Instituto de Ciencia de Materiales de Madrid.
    Effects on the structural and magnetic properties of amorphous ribbons of (Co0.94Fe0.06)(72.5)Si12.5B15 caused by 4 MeV Cl2+ ion irradiation2007In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 353, no 8-10, p. 879-882Article in journal (Refereed)
    Abstract [en]

    The use of energetic ion irradiation to modify magnetic materials has attracted increasing interest in recent years. The possibility of patterning surfaces on these materials offers a wide range of potential applications particularly in technologies related to magnetic storage media, sensing devices and electromagnetic shielding materials. In this work, ultrasoft non-magnetostrictive (Co0.94Fe0.06)72.5Si12.5B15 amorphous ribbons, 50 μm thick and 0.85 mm wide, fabricated by the chilly block melt spinning technique are irradiated, in their amorphous state, by 4 MeV Cl2+ ions with a fluence of 5 × 1013 cm-2. The hysteresis properties of both irradiated and non-irradiated samples are characterized by means of a vibrating sample magnetometer while surface magnetic domain structure is observed by Bitter technique. The presence of an induced magnetic anisotropy in irradiated samples is ascribed to the local damage, caused by ion irradiation treatment, which results in modified coercive field and permeability of the samples. X-ray diffraction results are presented to confirm the amorphicity of the structure even after irradiation with ions.

  • 29.
    Sanz, Ruy
    et al.
    Material Science Institute of Madrid.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Johansson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Skupinski, Marek
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Boman, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Hernandez-Velez, Manuel
    Vazquez, Manuel
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Well-ordered nanopore arrays in rutile TiO2 single crystals by swift heavy ion-beam lithography2007In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 18, no 30, p. 305303-Article in journal (Refereed)
    Abstract [en]

    Ion track lithography has been applied for transferring the self-ordered nanopattern of porous anodic alumina to single-crystalline rutile TiO2 substrates. As a result, nanometre resolved arrays have been fabricated with an aspect ratio ranging from 5 to 16, over areas of several square millimetres. Differences in the expected aspect ratio of the resulting nanopores in rutile TiO2 single crystals are analysed and discussed. Some of these differences may be ascribed to varying densities of the mask material.

  • 30. Sanz, Ruy
    et al.
    Johansson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Skupinski, Marek
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science. Materialvetenskap.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Boman, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Vázquez, Manuel
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science. Materialvetenskap.
    Fabrication of Well-Ordered High-Aspect-Ratio Nanopore Arrays in TiO2 Single Crystals2006In: Nano Letters, Vol. 6, no 5, p. 1065-1068Article in journal (Refereed)
    Abstract [en]

    In this work a successful method for producing high-aspect-ratio nanopatterned single-crystal TiO2 is presented. The method used is based on nanolithography involving swift heavy ion bombardment through a porous anodic alumina mask. Nanopatterning of large areas allows for fabrication of new devices, for example, photonic crystals and electrodes for energy storage and conversion. Crystalline TiO2 also presents optimal characteristics for optical and catalysis applications. Samples were irradiated by MeV Br7+ ions with fluencies ranging from 7.9 × 1013 to 1.2 × 1015 cm-2. The high-energy Br7+ ions induce latent tracks of amorphous material into the TiO2 crystal suitable for selective etching by hydrofluoric acid. High-aspect-ratio (16) nanopatterned areas, up to 4 mm2, were obtained in a single radiation spot onto single-crystalline TiO2.

  • 31. Schmidt, H.T.
    et al.
    Jensen, Jens
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Reinhed, P.
    Schuch, R.
    Stöchkel, K.
    Zettergren, H.
    Cederquist, H.
    Recoil-ion momentum distributions for transfer ionization in fast proton-He collisions2005In: Phys. Rev, Vol. A72Article in journal (Refereed)
  • 32.
    Skupinski, Marek
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Materialvetenskap.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Johansson, A
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Boman, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. Oorganisk kemi.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Ion track nanolithography2006Conference paper (Refereed)
  • 33.
    Skupinski, Marek
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Johansson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Jarmar, Tobias
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Razpet, Alenka
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Boman, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Carbon nanopillar array deposition on SiO2 by ion irradiation through a porous alumina template2007In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 82, no 3, p. 359-362Article in journal (Refereed)
    Abstract [en]

    A method for producing ordered carbon nanopillar arrays is presented. The method is based on ion irradiation through a small anodic porous alumina membrane, resulting in carbon deposition within the centers of the pores on a gold covered SiO2/Si substrate. Samples were irradiated by 4 MeV Cl2+ ions with fluences of . The combined use of pick’n place positioning of the small porous alumina templates and ion beam irradiation is well suited for post-processing on silicon based integrated circuits. It provides fast local deposition at low temperature of high-density ordered carbon nanopillar arrays in larger silicon based systems, e.g., for field emitting or biosensors applications.

  • 34.
    Skupinski, Marek
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Sanz, Ruy
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Surface Patterning by Heavy Ion Lithography Using Self-Assembled Colloidal Masks2007In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 257, no 1-2, p. 777-781Article in journal (Refereed)
    Abstract [en]

    Heavy ion lithography using self-assembled colloidal particles as a mask enables micro- and nano-patterning of surfaces. The resulting patterns can be tuned by varying the mask configuration, i.e. packing geometry of the colloidal particles and number of particle layers. In this work we present several patterns, which can be transferred to rutile TiO2 single crystals by irradiating through self-assembled layers of silica micro-spheres with 25 MeV Br ions. As the induced ion tracks in TiO2 have a very high etching selectivity the patterns can be developed in HF with very high contrast. This makes it possible to prepare large patterned areas which can be of interest for e.g. optical applications.

  • 35.
    Skupiński, Marek
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Johansson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science.
    Boman, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Razpet, Alenka
    Nanopattern transfer to SiO2 by ion track lithography and highly selective HF vapor etching2007In: Journal of Vacuum Science & Technology B, ISSN 1071-1023, E-ISSN 1520-8567, Vol. 25, no 3, p. 862-867Article in journal (Refereed)
    Abstract [en]

    The authors present a method for high aspect ratio nanopatterning of high density (1010  pores/cm2) self-assembled porous alumina membrane pattern into thermally grown SiO2 on silicon. The pattern transfer is accomplished by irradiating through 2  µm thick porous alumina membrane with swift heavy ions (4  MeV Cl2+). Ions passing through the nanopores in the mask at a fairly high fluence (typically 1014  ions/cm2) are impinging on the substrate and creating a continuous volume of overlapping ion tracks of damage. The damage is sufficient to be selectively etched by HF vapor from an aqueous HF solution. From an alumina mask with pores of 70  nm diameter, a pattern of pores of 77  nm in diameter and the same distance of 100  nm between the centers of the pores was transferred. The deepest observed etched pores were 355  nm, giving an aspect ratio of 5, which is up to 40 times larger compare to earlier work where HF wet etching was used. This ion track lithography technique shows a potential to produce nanostructures with even higher aspect ratios.

  • 36. Snyders, R.
    et al.
    Music, D.
    Sigumonrong, D.
    Schelnberger, B.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Schneider, J.M.
    Experimental and ab initio study of the mechanical properties of hydroxyapatite2007In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 90, no 19, p. 193902-Article in journal (Refereed)
    Abstract [en]

    The authors have studied the elastic properties of radio frequency sputtered phase pure, stoichiometric, and dense hydroxyapatite films by nanoindentation. The measured elastic modulus values have been compared to ab initio calculated data. The calculation technique was based on the determination of all elastic constants. The calculated and measured elastic modulus values differ by ∼10%. The good agreement indicates that the elasticity of hydroxyapatite can be described using ab initio calculations, establishing the elastic modulus thereof.

  • 37. Stöchkel, K.
    et al.
    Eidem, O.
    Cederquist, H.
    Zettergren, H.
    Reinhed, P.
    Schuch, R.
    Cocke, C. L.
    Levin, S. B.
    Ostrovsky, V. N.
    Källberg, A.
    Simonsson, A.
    Jensen, Jens
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Schmidt, H. T.
    Two-center interference in fast proton-H2-electron transfer and excitation processes2005In: Phys. Rev, Vol. A87, p. 050703-Article in journal (Refereed)
  • 38. Svensk, O
    et al.
    Törmä, P T
    Suihkonen, S
    Ali, M
    Lipsanen, H
    Sopanen, M
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Reduced photoluminescence from InGaN/GaN multiple quantum well structures irradiated by low fluence high energy heavy ions2008In: Book of Abstracts, Phalaborwa, South Africa, 2008Conference paper (Refereed)
  • 39. Tomita, S
    et al.
    Andersen, J.U.
    Cederquist, H.
    Concina, B.
    Huber, B.A.
    Hvelplund, P.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Liu, B.
    Manil, B.
    Maunoury, L.
    Brøndsted Nielsen, S.
    Rangama, J.
    Schmidt, H.T.
    Zettergren, H.
    Lifetimes of C_60^2- and C_70^2- dianions in a storage ring2006In: Journal of Chemical Physics, Vol. 124, p. 024310-Article in journal (Refereed)
  • 40. Vines, L.
    et al.
    Monakhov, E.
    Maknys, K.
    Svensson, B. G.
    Jensen, Jens
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Hallén, Anders
    Scanning probe microscopy of single Au ion impacts in Si2005In: Presented at the European Material Research Society (E-MRS 2005) Spring meeting, 2005Conference paper (Other scientific)
  • 41. Vines, L.
    et al.
    Monakhov, E.
    Maknys, K.
    Svensson, B.G.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Hallén, A.
    Kuznetsov, A.Y.
    Scanning probe microscopy of single Au-ion implants in Si2006In: Materials Science and Engineering C, Vol. 26, p. 782-Article in journal (Refereed)
  • 42. Vines, L.
    et al.
    Monakhov, E.
    Maknys, K.
    Svensson, B.G.
    Kuznetsov, A.
    Jensen, Jens
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Hallén, Anders
    Scanning capacitance microscopy of Si implanted with single Au+ ions2005In: Presented at the 21st Nordic Semiconductor Meeting, Oslo, Norway, 2005Conference paper (Other (popular scientific, debate etc.))
  • 43. Vines, L.
    et al.
    Monakhov, E.
    Svensson, B.G.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Hallén, A.
    Kuznetsov, A.Y.
    Visualization of MeV ion impacts in Si2006In: Physical Review B, Vol. 73, p. 085312-Article in journal (Refereed)
  • 44. Vines, L.
    et al.
    Monakhov, E.V.
    Kuznetsov, A.Y.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Svensson, B.G.
    Correlation between divacancy acceptor states in ion implanted n+p Si diodes studied by DLTS2006Conference paper (Other (popular science, discussion, etc.))
  • 45. Vuckovic, S
    et al.
    Popok, V N
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Nanostructure formation on rutile TiO2 surfaces by low-energy cluster and high-energy ion impact2008In: Book of Abstracts, Dresden, Germany, 2008Conference paper (Refereed)
  • 46. Zettergren, H.
    et al.
    Reinhed, P.
    Stochkel, K.
    Schmidt, H.T.
    Cederquist, H.
    Jensen, Jens
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Fragmentation and Ionization of C70 and C60 – a comparison2005In: Presented at the 24rd International Conference on Photonic, Electronic and Atomic Collisions (ICPEAC 2005), Rosario, Argentina, 2005Conference paper (Other (popular scientific, debate etc.))
  • 47. Zettergren, H.
    et al.
    Reinhed, P.
    Støchkel, K.
    Schmidt, H.T.
    Cederquist, H.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Tomita, S.
    Nielsen, S.B.
    Hvelplund, P.
    Manil, B.
    Rangama, J.
    Huber, H.A.
    Fragmentation and ionization of C_70 and C_60 by slow ions of intermediate charge2006In: The European Physical Journal D, Vol. 38, p. 299-Article in journal (Refereed)
  • 48. Zettergren, H.
    et al.
    Schmidt, H. T.
    Cederquist, H.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Hvelplund, P.
    Tomita, S.
    Manil, B.
    Rangama, J.
    Huber, B.A.
    Even-odd effects in the ionization cross sections of [C60]2 and [C60C70] dimers2007In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 75, no 5, p. 051201-Article in journal (Refereed)
    Abstract [en]

    We report strong even-odd effects in multiple ionization yields of van der Waals dimers in slowXe30+ + ͓C60͔2͓͑C60C70͔͒ →  ̄ + ͓C60͔2r+͓͑C60C70͔r+͒ electron-transfer collisions as functions of r Յ 7. Thisbehavior may be due to even-odd variations in the sequences of dimer ionization energies as calculated with anelectrostatic model including an electrical fullerene-fullerene contact at the 19a0 center-center separation in͓C60͔2+. Prompt dissociations predominantly yield intact fullerenes ͓C60͔2r+ → C60r1+ + C60r2+ in the same͑r1 = r2, even r͒ or nearby ͑r1 = r2 ± 1, odd r Ͼ 1͒ charge states.

  • 49.
    Zettergren, H.
    et al.
    Stockholms universitet.
    Schmidt, H.T.
    Stockholms universitet.
    Reinhed, P.
    Stockholms universitet.
    Cederquist, H.
    Stockholms universitet.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Hvelplund, P.
    Department of Physics and Astronomy, University of Aarhus.
    Tomita, S.
    Institute of Applied Physics, University of Tsukuba.
    Manil, B.
    Centre Interdisciplinaire Recherches Ions Lasers (CIRIL).
    Rangama, J.
    Centre Interdisciplinaire Recherches Ions Lasers (CIRIL).
    Huber, B.A.
    Centre Interdisciplinaire Recherches Ions Lasers (CIRIL).
    Stabilities of multiply charged dimers and clusters of fullerenes2007In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 126, no 22, p. 224303-Article in journal (Refereed)
    Abstract [en]

    The authors find even-odd variations as functions of r (...+[C60]2(r+)([C60C70](r+)) electron-transfer collisions. This even-odd behavior is in sharp contrast to the smooth one for fullerene monomers and may be related to even-odd effects in dimer ionization energies in agreement with results from an electrostatic model. The kinetic energy releases for dimer dissociations [predominantly yielding intact fullerenes [C60]2(r+)-->C60(r1+)+C60(r2+) in the same (r1=r2) or nearby (r1=r2+/-1) charge states] are found to be low in comparison with the corresponding model results indicating that internal excitations of the separating (intact) fullerenes are important. Experimental appearance sizes for the heavier clusters of fullerenes [C60]n(r+) (n>3 and r=2-5) compare well with predictions from a new nearest-neighbor model assuming that r unit charges in [C60]n(r+) are localized to r C60 molecules such that the Coulomb energy of the system is minimized. The system is then taken to be stable if (i) two (singly) charged C60 are not nearest neighbors and (ii) the r C60(+) molecules have binding energies to their neutral nearest neighbors which are larger than the repulsive energies for the (r-1) C60(+)-C60(+) pairs. Essential ingredients in the nearest-neighbor model are cluster geometries and the present results on dimer stabilities.

  • 50.
    Zhang, Y.
    et al.
    Pacific Northwest National Laboratory.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Grove, D.A.
    Bae, I.T.
    Pacific Northwest National Laboratory.
    Weber, W.J.
    Pacific Northwest National Laboratory.
    Stopping power measurements of He ions in Si and SiC by time-of-flight spectrometry2007In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 261, no 1-2, p. 1180-1183Article in journal (Refereed)
    Abstract [en]

    A straightforward approach is introduced to determine electronic stopping powers of He ions in Si and SiC over a continuous range of energies. In transmission geometry, the energy loss of He ions in self-supporting stopping foils of Si and SiC is measured using a time-of-flight (TOF) set-up. The energy of individual ions prior to impingement on the foil is determined from its TOF data; the exit energy after the stopping foil is measured using a Si detector, for which every channel has been calibrated using the TOF data without the stopping foil present. The measured stopping powers demonstrate excellent repeatability of this experimental approach and good reliability as compared with previous data from the literature and theoretical predictions.

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