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| 2. |
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| 3. |
- Giovanelli, L., et al.
(författare)
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Electronic structure of self-assembled organic/inorganic semiconductor interfaces : lead phthalocyanine on InSb and InAs(100)-4X2/c(8 X2)
- 2001
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Ingår i: Journal of Electron Spectroscopy and Related Phenomena. - 0368-2048 .- 1873-2526. ; 114, s. 375-381
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Tidskriftsartikel (refereegranskat)abstract
- The interfacial properties of ultra thin films of lead-phthalocyanine deposited in situ onto InSb and InAs(100)-4X2/c(8X2) clean surfaces have been studied by synchrotron radiation core level and valence band photoelectron spectroscopy. The interaction between the overlayers and the substrates was determined upon analyzing the changes in the photoemission spectra between room and higher annealing temperatures, leading to ordered monolayer films. While weaker than on other substrates, a reactivity is nevertheless present: the organic macrocycle preserves its integrity up to 320 degreesC but the Pb central atom first leaves the molecules most probably to be incorporated in the substrate surface, before being desorbed at higher temperatures.
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| 4. |
- Papageorgiou, N., et al.
(författare)
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High resolution synchrotron radiation PES study of PbPc deposited on Pt(111)
- 2000
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Ingår i: Applied Surface Science. - 0169-4332 .- 1873-5584. ; 162, s. 178-183
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Tidskriftsartikel (refereegranskat)abstract
- We studied lead phthalocyanine (PbPc) films sublimated under UHV conditions on a clean Pt(111) substrate. We report results from high resolution photoelectron spectra of the Pb 5d, Ph 4f, C 1s, N 1s and Pt 4f core level using synchrotron radiation. Comparison between ultra thin films and thicker films shows that the first molecular adlayer interacts strongly with the substrate and we report evidence of Pb-Pt alloy formation on the surface. For the thick films, the C Is and N Is core level spectra show usual characteristics, however in the case of ultra thin films, we note important differences with respect to some previous results.
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| 5. |
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| 6. |
- Suchodolskis, A., et al.
(författare)
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Photoemission and optical spectroscopy of i-ZnMgEr quasicrystal
- 2005
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Ingår i: Acta Physica Polonica. A. - 0587-4246 .- 1898-794X. ; 107:2, s. 412-419
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Tidskriftsartikel (refereegranskat)abstract
- The results of photoemission and optical studies of icosahedral single-grain ZnMgEr quasicrystals are presented. Synchrotron radiation photoemission measurements were performed on in situ cleaved samples at 10(-10) mbar pressure and low, 140-150 K temperature. The valence band photoemission spectra measured reveal a simple metal-type valence band of icosahedral ZnMgEr with a distinct Fermi edge cut-off and with a sharp pseudogap feature. The photoemission spectra of shallow Mg 2p and Zn 3d core levels indicate a coordination shift of Mg 2p spin-orbit doublet and an oscillating dependence of Zn 3d photoemission line components on the photon energy within the hv = 20-160 eV range investigated. The optical response of icosahedral ZnMgEr, a dispersion of the dielectric function, was measured by the spectroscopic ellipsometry technique in the 0.5-5.0 eV spectral range. The optical spectra of the quasicrystal indicate the Drude-type optical response superimposed with a peak of interband optical transitions. The interband optical transitions can be modelled with the pseudogap parameters which agree with those deduced in an analysis of the photoemission valence band spectra.
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| 7. |
- Giovanelli, L., et al.
(författare)
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Synchrotron radiation photoelectron spectroscopy study of Pb-Pc thin films on InSb(100)-(4x2)/c(8x2)
- 2001
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Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 486:02-jan, s. 55-64
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Tidskriftsartikel (refereegranskat)abstract
- The electronic properties and the thermal stability of a thin film of lead-phthalocyanine deposited on the InSb(100)-(4 x 2)/c(8 x 2) surface were studied by synchrotron radiation core level and valence band photoelectron spectroscopy. The interaction between the overlayer and the substrate was determined by analyzing the photoemission spectra of a thin film and of a single monolayer of adsorbed molecules. Subsequently the monolayer was annealed at increasing temperatures, leading first to a gradual change of the oxidation state of the central lead atom, then to a fragmentation of the macrocycle itself.
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| 8. |
- Honour, JW, et al.
(författare)
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Procedure for neonatal screening for congenital adrenal hyperplasia due to 21-hydroxylase deficiency
- 2001
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Ingår i: Hormone research. - : S. Karger AG. - 0301-0163. ; 55:4, s. 201-205
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Tidskriftsartikel (refereegranskat)abstract
- The value of screening of neonates for congenital adrenal hyperplasia is not universally accepted. Procedures for screening are recommended here in order to provide a structure to the testing and ultimately bring together data that will allow the effect of screening to be judged for benefit or dismissed as no better than clinical recognition of the disease state.
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| 9. |
- Karpus, V., et al.
(författare)
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Mg 2p shallow core-level and local atomic structure of i-ZnMgRE quasicrystals
- 2006
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 252:15, s. 5411-5414
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Tidskriftsartikel (refereegranskat)abstract
- We present a detailed analysis of the Mg 2p shallow core-levels measured on icosahedral single-grain ZnMgY, ZnMgHo, and ZnMgEr quasicrystals during a photoelectron microscopy study. The synchrotron radiation photoemission measurements were performed on in situ cleaved samples at a pressure of 10(-10) mbar and at low temperature, typically 90-150 K. The Mg 2p photoemission lines are essentially broadened as compared to those of the Mg 2p spin-orbit doublet recorded on the Zn2Mg crystalline Laves phase. The broadening is associated to the coordination shifts of the Mg 2p level due to the inequivalent magnesium sites in the quasicrystalline lattice. The coordination shifts are calculated on the basis of i-ZnMg(Ho, Y) atomic structure data, recently determined from the pair distribution function analysis. The coordination shifts obtained are up to 0.2 eV. The Mg 2p experimental spectral intensity is nicely reproduced by a superposition of coordination-shifted Mg 2p spin-orbit doublets.
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| 10. |
- Papageorgiou, N., et al.
(författare)
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Lead phthalocyanine thin films on InAs(100)-(4 x 2)/c(8 x 2) studied by synchrotron radiation photoelectron spectroscopy
- 2001
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Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 482, s. 1199-1204
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Tidskriftsartikel (refereegranskat)abstract
- We used synchrotron radiation photoelectron spectroscopy to study the interface between a thin film and an ordered single monolayer of lead phthalocyanine (PbPc) deposited on the clean InAs(1 0 0)-(4 x 2)/c(8 x 2) reconstructed surface. Analysis of the core level and valence band spectra gave information about the electronic properties of the interface, the interaction between the molecule and the substrate and the valence band offset of the heterojunction.
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| 11. |
- Sinner-Hettenbach, M., et al.
(författare)
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Electronic structure of SnO2(110)-4 x 1 and sputtered SnO2(110) revealed by resonant photoemission
- 2002
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Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 499:1, s. 85-93
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Tidskriftsartikel (refereegranskat)abstract
- The surface properties of SnO2(1 1 0)-4 x 1 and sputtered SnO2(1 1 0) were studied comparatively by resonant photoemission of the valence band states in a photon energy range of 60-130 eV. Resonating energetic levels could be observed on the 4 x I reconstructed surface and the resonance behavior could be switched off by sputter treatment. Additionally, the Sn 4d core-levels were recorded at two photon energies in order to allow a statement about the surface's stoichiometry. A tentative explanation of the observed resonance and of the discrepancy between ordered and sputtered surface is given with regard to recent STM results on similar prepared surfaces.
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| 12. |
- Sinner-Hettenbach, M., et al.
(författare)
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High resolution photoemission study on SnO2 gas sensors
- 2001
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Ingår i: Thin Solid Films. - 0040-6090 .- 1879-2731. ; 391:2, s. 192-197
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Tidskriftsartikel (refereegranskat)abstract
- Pd-, Pt-doped and undoped SnO2 gas sensors were studied by synchrotron radiation photoelectron spectroscopy (SRPES) and laboratory source UPS (ultraviolet photoelectron spectroscopy). Valence band spectra were recorded for photon energies of 60-120 eV (SRPES) and for 40.81 eV (UPS). The spectra were analyzed by factor analysis and generation of difference spectra. A comparison of the samples shows that the doping material of these sensors is not introducing additional states to the surface electronic structure within the limit of detection. This leads to the conclusion that the surfaces of the grains are not enriched with the metal additives.
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| 13. |
- Suchodolskis, A., et al.
(författare)
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Indication of van Hove singularities in the density of states of ZnMg(Y,Ho) quasicrystals
- 2003
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 68:5
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Tidskriftsartikel (refereegranskat)abstract
- We present a low-temperature synchrotron-radiation photoelectron microspectroscopy study of the valence bands of single-grain icosahedral ZnMgY and ZnMgHo quasicrystals. Their valence band photoemission spectra reveal in both cases a simple metal-type behavior with a clear metallic Fermi edge and a sharp pseudogap feature: the spectral intensity exhibits a maximum at approximate to0.7 eV below the chemical potential and a subsequent decrease as the Fermi level is approached. The analysis of the pseudogap feature, based on the band-structure hypothesis, shows that it corresponds to the van Hove singularities in the density of states (DOS), which originate from the intersections of the isoenergetic surface with the 222100 and 311111 Bragg planes. The reconstructed density of states agrees in general trends with the theoretical first-principles DOS of hexagonal ZnMgY approximants, and correctly reproduces the experimental value of i-ZnMgY electronic specific-heat coefficient.
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| 14. |
- Suchodolskis, A., et al.
(författare)
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Pseudogap structure in icosahedral ZnMgY and ZnMgHo quasicrystals
- 2003
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Ingår i: Applied Surface Science. - 0169-4332 .- 1873-5584. ; 212, s. 485-490
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Tidskriftsartikel (refereegranskat)abstract
- The results of a photoemission study of icosahedral single-grain ZnMg(Y, Ho) quasicrystals and their crystalline approximant Zn2Mg are presented. Synchrotron radiation photoemission measurements have been performed on in situ cleaved samples at low temperature of approximate to90 K and 10(-10) mbar pressure. The spectra obtained indicate simple metal-type valence bands (VB) with distinct Fermi edge cutoff. Analysis of the Fermi edge spectra reveals the presence of a pseudogap in i-ZnMg(Y, Ho) quasicrystals. The pseudogap corresponds to a rather sharp DOS dip at the Fermi level with th approximate to50% (of the normal DOS) depth and the approximate to0.8 eV width. The values of i-ZnMg(Y, Ho) pseudogap parameters are comparable with those of other quasicrystals.
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| 15. |
- Suchodolskis, A., et al.
(författare)
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Valence band structure of i-ZnMgEr quasicrystal : photoemission study
- 2004
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Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 16:50, s. 9137-9142
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Tidskriftsartikel (refereegranskat)abstract
- The results of photoemission study of icosahedral single-grain ZnMgEr quasicrystals are presented. Synchrotron radiation photoemission measurements were performed on in situ cleaved samples at 10(-10) mbar pressure and low, 140-150 K, temperature. The valence band photoemission spectra measured reveal a simple-metal type valence band of i-ZnMgEr with a distinct Fermi edge cutoff and a spectral feature at 0.7 eV below epsilon(F). Analysis of the PE spectra shows that the spectral feature observed corresponds to the van Hove singularities in the density of states, which are due to intersections of the Fermi surface with the 222100 and 311111 Bragg planes.
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