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Author Bittencourt, C.; Krüger, P.; Lagos, M.J.; Ke, X.; Van Tendeloo, G.; Ewels, C.; Umek, P.; Guttmann, P. pdf  url
doi  openurl
  Title Towards atomic resolution in sodium titanate nanotubes using near-edge X-ray-absorption fine-structure spectromicroscopy combined with multichannel multiple-scattering calculations Type A1 Journal article
  Year (down) 2012 Publication Beilstein journal of nanotechnology Abbreviated Journal Beilstein J Nanotech  
  Volume 3 Issue Pages 789-797  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Recent advances in near-edge X-ray-absorption fine-structure spectroscopy coupled with transmission X-ray microscopy (NEXAFS-TXM) allow large-area mapping investigations of individual nano-objects with spectral resolution up to E/Delta E = 104 and spatial resolution approaching 10 nm. While the state-of-the-art spatial resolution of X-ray microscopy is limited by nanostructuring process constrains of the objective zone plate, we show here that it is possible to overcome this through close coupling with high-level theoretical modelling. Taking the example of isolated bundles of hydrothermally prepared sodium titanate nanotubes ((Na,H)TiNTs) we are able to unravel the complex nanoscale structure from the NEXAFS-TXM data using multichannel multiple-scattering calculations, to the extent of being able to associate specific spectral features in the O K-edge and Ti L-edge with oxygen atoms in distinct sites within the lattice. These can even be distinguished from the contribution of different hydroxyl groups to the electronic structure of the (Na,H)TiNTs.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000311482400001 Publication Date 2012-11-23  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2190-4286; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.127 Times cited 13 Open Access  
  Notes Approved Most recent IF: 3.127; 2012 IF: 2.374  
  Call Number UA @ lucian @ c:irua:105140 Serial 3684  
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Author Navío, C.; Vallejos, S.; Stoycheva, T.; Llobet, E.; Correig, X.; Snyders, R.; Blackman, C.; Umek, P.; Ke, X.; Van Tendeloo, G.; Bittencourt, C.; pdf  doi
openurl 
  Title Gold clusters on WO3 nanoneedles grown via AACVD : XPS and TEM studies Type A1 Journal article
  Year (down) 2012 Publication Materials chemistry and physics Abbreviated Journal Mater Chem Phys  
  Volume 134 Issue 2/3 Pages 809-813  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract We have prepared tungsten oxide films decorated with gold particles on Si substrates by aerosol assisted chemical vapor deposition (AACVD) and characterized them using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). SEM shows that the films are composed of needle-like structures and TEM shows that both the needles and the gold particles are crystalline. XPS indicates the presence of oxygen vacancies, i.e. the films are WO3−x, and hence the deposited material is composed of semiconducting nanostructures and that the interaction between the gold particles and the WO3 needles surface is weak. The synthesis of semiconducting tungsten oxide nanostructures decorated with metal particles represents an important step towards the development of sensing devices with optimal properties.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Lausanne Editor  
  Language Wos 000305918200038 Publication Date 2012-04-30  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0254-0584; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.084 Times cited 52 Open Access  
  Notes Iap Approved Most recent IF: 2.084; 2012 IF: 2.072  
  Call Number UA @ lucian @ c:irua:97705 Serial 1356  
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Author Guttmann, P.; Bittencourt, C.; Rehbein, S.; Umek, P.; Ke, X.; Van Tendeloo, G.; Ewels, C.P.; Schneider, G. pdf  doi
openurl 
  Title Nanoscale spectroscopy with polarized X-rays by NEXAFS-TXM Type A1 Journal article
  Year (down) 2012 Publication Nature photonics Abbreviated Journal Nat Photonics  
  Volume 6 Issue 1 Pages 25-29  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Near-edge X-ray absorption spectroscopy (NEXAFS)1 is an essential analytical tool in material science. Combining NEXAFS with scanning transmission X-ray microscopy (STXM) adds spatial resolution and the possibility to study individual nanostructures2, 3. Here, we describe a full-field transmission X-ray microscope (TXM) that generates high-resolution, large-area NEXAFS data with a collection rate two orders of magnitude faster than is possible with STXM. The TXM optical design combines a spectral resolution of E/ΔE = 1 × 104 with a spatial resolution of 25 nm in a field of view of 1520 µm and a data acquisition time of ~1 s. As an example, we present image stacks and polarization-dependent NEXAFS spectra from individual anisotropic sodium and protonated titanate nanoribbons. Our NEXAFS-TXM technique has the advantage that one image stack visualizes a large number of nanostructures and therefore already contains statistical information. This new high-resolution NEXAFS-TXM technique opens the way to advanced nanoscale science studies.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000298416200011 Publication Date 2011-11-25  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1749-4885;1749-4893; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 37.852 Times cited 76 Open Access  
  Notes Approved Most recent IF: 37.852; 2012 IF: 27.254  
  Call Number UA @ lucian @ c:irua:94198 Serial 2272  
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Author Guttmann, P.; Bittencourt, C.; Ke, X.; Van Tendeloo, G.; Umek, P.; Arcon, D.; Ewels, C.P.; Rehbein, S.; Heim, S.; Schneider, G. pdf  url
doi  openurl
  Title TXM-NEXAFS of TiO2-based nanostructures Type P1 Proceeding
  Year (down) 2011 Publication AIP conference proceedings Abbreviated Journal  
  Volume 1365 Issue Pages 437-440  
  Keywords P1 Proceeding; Electron microscopy for materials research (EMAT)  
  Abstract In this work, electronic properties of individual TiOx-pristine nanoribbons (NR) prepared by hydrothermal treatment of anatase TiO(2) micro-particles were studied using the HZB transmission x-ray microscope (TXM) at the BESSY II undulator beamline U41-FSGM. NEXAFS is ideally suited to study TiO(2)-based materials because both the O K-edge and Ti L-edge features are very sensitive to the local bonding environment, providing diagnostic information about the crystal structures and oxidation states of various forms of titanium oxides and sub-oxides. TXM-NEXAFS combines full-field x-ray microscopy with spectroscopy, allowing the study of the electronic structure of individual nanostructures with spatial resolution better than 25 nm and a spectral resolution of up to E/Delta E = 10000. The typical image field in TXM-NEXAFS measurements is about 10 mu m. 10 mu m, which is large compared to the individual nanoparticle. Therefore, one image stack already contains statistically significant data. In addition, the directional electric field vector ((E) over bar) of the x-rays can be used as a “search tool” for the direction of chemical bonds of the atom selected by its absorption edge.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication New York Editor  
  Language Wos 000298672400103 Publication Date 2011-09-19  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited 2 Open Access  
  Notes Approved Most recent IF: NA  
  Call Number UA @ lucian @ c:irua:113071 Serial 3789  
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