Dr. Andreas Schaefer University of Bremen Institute for Applied and Physical Chemistry (IAPC) P.O. Box 330 440 D-28334 Bremen Tel: +49-421-218 63175 eMail: andreas.schaefer@uni-bremen.de

Research interests

• Growth and characterization of oxide thin film model systems
• Rare earth oxides for catalytic and microelectronic applications
• Alternative methods for oxide preparation in UHV
• Photoelectron spectroscopy of oxide materials
• Modification and characterization of nanoporous gold in UHV

Used Methods

• X-ray Photoelectron Spectroscopy (XPS)
• Synchrotron Radiation based techniques (PES, XAS) at MAX-lab, Sweden
• Electron Diffraction (LEED, SPA-LEED, RHEED)
• Thermal Desorption Spectroscopy (TDS)
• Infrared Reflection Absorption Spectroscopy (IRAS)

Present and Past Collaborations

• Prof. Jason F. Weaver, University of Florida, Gainesville, U.S.A.
• Dr. Jan Ingo Flege, Institute of solid state phyics, University Bremen
• Prof. Thomas Schröder, IHP Microelectronics, Frankfurt (Oder), Germany
• Prof. Anders Sandell, Uppsala University, Uppsala, Sweden
• Prof. Anne Borg, Norwegian University of Science and Technology, Trondheim, Norway

Curriculum vitae

• Since 01/2012: Postdoctral researcher at the Institute for Applied and Physical Chemistry (Prof. Dr. Marcus Bäumer)
  Project coordination rare earth oxide thin film model systems for catalysis and microelectronics
• 05/2011-12/2011: Guest researcher at the Department of Physics and Astronomy, Devision of Molecular and Condensed Matter Physics, Uppsala Sweden; Group of Prof. Dr. Anders Sandell
  Surface materials from molecular precursors (TiO₂ growth on gold by CVD in UHV, preparation strategies for rare earth oxide thin films)
• 05/2010-04/2011: Postdoctoral researcher at the Department of Physics and Astronomy, Devision of Molecular and Condensed Matter Physics, Uppsala Sweden; Group of Prof. Dr. Anders Sandell
  Surface materials from molecular precursors (TiO₂ growth on gold by CVD in UHV, modification of nanoporous gold)
• 04/2006-03/2010: PhD student at the University of Bremen, Germany at the Institute for Applied and Physical Chemistry (Prof. Dr. Marcus Bäumer) and the Institute of Solid State Physics (Prof. Dr. Jens Falta)
  Thesis: “Preparation and characterization of praseodymium oxide thin films on silicon substrates as model systems for catalysis and microelectronics”
• 07/2005-03/2006: Diploma student at the University of Bremen, Germany at the Institute for Applied and Physical Chemistry; Group of Prof. Dr. Marcus Bäumer
• 10/2001-06/2005: Study of Chemistry (Diploma) at the University of Bremen, Germany

Awards

• 01/2011: Award for PhD thesis
  (Bremer Studienpreis founded by Bruker Daltronics GmbH)

List of publications

2014

¹⁹ D. Ragazzon, M. H. Farstad, A. Schaefer, L. E. Walle, P. Uvdal, A. Borg, A. Sandell, “Growth of TiO₂(B)(001) on Au(111) by Chemical Vapor Deposition”, submitted (2014)

¹⁸ W. Cartas, R. Rai, A. Sathe, A. Schaefer, J. F. Weaver, “Oxidation of a Tb₂O₃(111) Thin Film on Pt(111) by Gas-Phase Oxygen Atoms”, accepted for publication, Journal of Physical Chemistry C, DOI: 10.1021/jp505310y

¹⁷ J. Shi, A. Schaefer, A. Wichmann, M. M. Mangir, Th. Gesing, A. Wittstock, M. Bäumer, “Nanoporous Gold Supported Ceria for the Water Gas Shift Reaction: UHV Inspired Design for Applied Catalysis”, accepted for publication, Journal of Physical Chemistry C, DOI: 10.1021/jp505433a

¹⁶ H. Wilkens, S. Gevers, S. Röhe, A. Schaefer, M. Bäumer, M. Zöllner, T. Schroeder, J. Wollschlaeger, “Structural Changes of Ultra Thin cub-PrO₂(111)/Si(111) Films Due to Thermally Induced Oxygen Desorption”, The Journal of Physical Chemistry C, 118 (2014), 3056−3061, DOI: 10.1021/jp4082917

2013

¹⁵ M. H. Zoellner, G.Niu, J.-H. Jhang, A. Schaefer, P. Zaumseil, M. Bäumer, and Th. Schroeder
“Temperature-Dependent Reduction of Epitaxial Ce_1-xPr_xO_2-? (x = 0-1) Thin Films on Si(111): A Combined Temperature-Programmed Desorption, X-ray Diffraction, X-ray Photoelectron Spectroscopy, and Raman Study”, The Journal of Physical Chemistry C, 117, (2013), 24851, DOI: 10.1021/jp4082867

¹⁴ J.-H. Jhang, A. Schaefer, W. Cartas, S. Epuri, M. Bäumer, J. F. Weaver, Growth and Partial Reduction of Sm₂O₃(111) Thin Films on Pt(111): Evidence for the Formation of SmO, The Journal of Physical Chemistry C, 117, (2013), 21396 DOI: 10.1021/jp4074416

¹³ H. Wilkens, O. Schuckmann, R. Oelke, S. Gevers, M. Reichling, A. Schaefer, M. Bäumer, M. H. Zoellner, T. Schroeder, and J. Wollschläger, Structural transitions of epitaxial ceria films on Si(111), Physical Chemistry Chemical Physics, 15, (2013,) 18589

¹² D. Ragazzon, A. Schaefer, M.H. Farstad, L.E. Walle, P. Palmgren, A. Borg, P. Uvdal, and A. Sandell, Chemical Vapor Deposition of Ordered TiO_x Nanostructures on Au(111), Surface Science, 617 (2013), 211-217, DOI: 10.1016/j.susc.2013.07.019

¹¹ A. Schaefer, D. Ragazzon, L.E. Walle, M.H. Farstad, A. Wichmann, A. Borg, M. Bäumer, and A. Sandell, Controlled modification of nanoporous gold: Chemical vapor deposition of TiO₂ in ultrahigh vacuum, Applied Surface Science, 282 (2013), 439-443, DOI: 10.1016/j.apsusc.2013.05.148

¹⁰ H. Wilkens, O. Schuckmann, R. Oelke, S. Gevers, A. Schaefer, M. Bäumer, M. H. Zoellner, T. Schroeder, and J. Wollschläger, Stabilization of the ceria iota-phase (Ce₇O₁₂) surface on Si(111), Applied Physics Letters, 102 (2013), 111602, DOI: 10.1063/1.4795867

⁹ S. Röhe, K. Frank, A. Schaefer, A. Wittstock, V. Zielasek, A. Rosenauer, M. Bäumer, CO oxidation on nanoporous gold: A combined TPD and XPS study of active catalysts, Surf. Sci., 609 (2013) 106-112, DOI: 10.1016/j.susc.2012.11.011

2012

⁸ A. Schaefer, D. Ragazzon, A. Wittstock, L.E. Walle, A. Borg, M. Bäumer, and A. Sandell, Towards Controlled Modification of Nanoporous Gold. A Detailed Surface Science Study on Cleaning and Oxidation, J. Phys. Chem C, 116 (2012) 4564, DOI: 10.1021/jp207638t

2011

⁷ S. Gevers, T. Weisemoeller, A. Schaefer, V. Zielasek, M. Bäumer, and J. Wollschläger, Structure of oxygen-plasma-treated ultrathin praseodymia films on Si(111), Phys. Rev. B, 83 (2011) 193408 DOI: 10.1103/PhysRevB.83.193408

⁶ A. Schaefer, S. Gevers, V. Zielasek, T. Schroeder, J. Falta, J. Wollschläger, and M. Bäumer, Photoemission study of praseodymia in its highest oxidation state: the necessity of in-situ plasma treatment, J. Chem. Phys., 134 (2011) 054701, DOI:10.1063/1.3516953

⁵ A. Ryzhkova, U. Jarzak, A. Schaefer, M. Bäumer, and P. Swiderek, Modification of surface properties of thin polysaccharide films by low-energy electron exposure, Carboh. Polymers, 83 (2011) 608 DOI: 10.1016/j.carbpol.2010.08.029

2010

⁴ A. Schaefer, A. Sandell, L.E. Walle, V. Zielasek, M. Schowalter, A. Rosenauer, M. Bäumer, Chemistry of thin film formation and stability during praseodymium oxide deposition on Si(111) under oxygen-deficient conditions, Surf. Sci., 604 (2010) 1287 DOI: 10.1016/j.susc.2010.04.016

2009

³ A. Schaefer, V. Zielasek, Th. Schmidt, A. Sandell, M. Schowalter, O. Seifarth, L. E. Walle, Ch. Schulz, J. Wollschlager, T. Schroeder, A. Rosenauer, J. Falta, M. Bäumer, Growth of Praseodymium Oxide Films Under Oxygen Deficient Conditions, Phys. Rev. B., 80 (2009) 045414 DOI: 10.1103/PhysRevB.80.045414

² A. Wittstock, B. Neumann, A. Schaefer, K. Dumbuya, Ch. Kübel, M.M. Biener, V. Zielasek, H.-P. Steinrück, J.M. Gottfried, J. Biener, A. Hamza, M. Bäumer, Nanoporous Au: An Unsupported Pure Gold Catalyst?, J. Phys. Chem. C, 113 (2009) 5593 DOI: 10.1021/jp808185v

2007

¹ A. Schaefer, T. Schroeder, G. Lupina, Yu. Borchert, J. Dabrowski, Ch. Wenger, M. Bäumer, Heteroepitaxial praseodymium sesquioxide films on Si(111): A new model catalyst system for praseodymium oxide based catalysts, Surf. Sci., 601 (2007) 1473 DOI: 10.1016/j.susc.2006.12.080