© ICAN 2019 | figure 1

What is photoelectron spectroscopy?

Photoelectron spectroscopy allows the determination of the elemental composition of a surface. It can distinguish between different elements as well as determine their precise bonding states. E.g. the signal of a carbon atom in a C-C bond differs from that of a carbon atom in a C-O bond.

The method is based on the detection of photoelectrons, emitted from the investigated surface under the illumination of (monochromatic) x-rays. One can distinguish between X-ray photoelectron spectroscopy (XPS, hν > 100 eV) and ultraviolett photoelectron spectroscopy (XPS, hν < 100 eV). The latter can be used to investigate the valence band of surfaces and molecular orbital energies.

The ICAN uses primarily a Versaprobe IITM by ULVAC-Phi. It offers a small minimal beam size of < 10 µm with a spectral resolution of 0.5 eV. Additionally x-ray induced electron imaging (SXI) allows for the in-situ imaging on the µm scale.

Figure 1: Schematic diagram of the excitation process in photoelectron spectroscopy. A x-ray photon an electron from a core-shell of the atom (here 1s). The photon energy is converted into kinetic energy of the electron, which is emitted into vacuum. Knowing the photon energy and measuring the kinetic energy of the electron then allows for determination of the binding energy of the electron.

© ICAN 2019 | figure 2

Chemical analysis

The kinetic energy of the emitted electron depends on the element from which it originates, as well as from the precise bonding state of that atom. Picking up the carbon example from above, an electron from a carbon 1s shell has ~3eV kinetic energy less, if the atom is in a C=O double bon, rather than a in a C-C single bond.

In figure 2 the Au 4f signal of a thin layer of gold nanoparticles is shown. A precise analysis yields, that roughly 6% of the gold atoms in the particles are oxidized, either as Au1+ or Au3+.

Figure 2: Intensity of the Au 4f peak of a thin gold nanoparticle layer. Small amounts of the gold is oxidized, which is why to additional peaks, representing the Au1+ (orange) and Au3+ (cyan) states are needed to describe the data.

© ICAN 2019 | figure 3

Illustrations using SXI

The following graph shows the detected X-ray induced secondary electrons (SXI) of a partially laser sintered TiO2 nanoparticle surface.

A laser was fired at the surface at 9 locations, varying the power of the laser. The variation of the laser power leads to a different degree of sintering of the TiO2 particles and thus to a different colour contrast.

Figure 3: An SXI of a laser-sintered TiO2 surface. The sintered surfaces are clearly visible.

Depth profiles and sputtering

With the existing system, it is possible to remove the surface of the sample to be examined by sputtering with argon ions.

On the one hand, this serves to clean the surface, as shown in Figure 4. By sputtering step by step, the antimony oxide layer that has formed on the surface of the sample is removed, leaving a pure, unoxidised antimony layer.

Furthermore, depth profiles can be recorded. After each sputtering step, the XPS intensity of the signal of the elements under investigation is determined. If the sputtering rate is known, the change in element concentration with increasing sample depth can be determined. An example is shown in Figure 5. It shows the intensity of Bi,Sb and Te of a BiSbTe3 layer as a function of the sputtering time. In this case, it can be seen that the concentration of tellurium and antimony decreases slightly with increasing depth.

© ICAN 2019 | figure 4

Figure 4: Change of the Sb 3d signal with an oxidised Sb surface and stepwise cleaning by sputtering with Ar ions.

© ICAN 2019 | figure 5

Figure 5: Depth profile of the intensity of the Sb, Te and Bi signal of a BiSbTe3 surface. By gradually removing the surface and measuring the signal intensity, a change in the composition of the layer can be detected.

© ICAN 2019 | figure 6

2D chemical maps

With the help of the high spatial resolution of the X-ray beam, it is possible to record 2-dimensional maps of the chemical composition of a surface.

Figure 6 shows an example of this. Iron oxide and silicon nitride particles were applied to the sample as powder and measured. An area of just under 0.075 mm2 is shown. The intensity of the particles is colour-coded. The red areas show the iron oxide, while the blue areas represent silicon nitride.

Figure 6: Chemical map of Fe2O3 and SiN nanoparticles. The red coloured areas consist only of Fe2O3, the blue ones of SiN.

© ICAN 2019 | figure 7

Surface and Quantum Well States

The high spectral resolution of He I light, depending on the system under investigation, combined with the smallest possible acceptance angle, enables the measurement of surface and quantum well states.

Figure 7 shows the monolayer dependence of these states of a crystalline magnesium layer on silicon. Depending on the layer thickness, one or more quantum well states and the increasingly sharp surface state can be seen.

Figure 7: UPS measurement of the surface state and quantum well states of a thin crystalline magnesium layer.

© ICAN 2019 | figure 8

Determination of the work function

With the UPS it is possible to determine the work function of a surface. This is especially possible for metallic samples that have a non-vanishing electronic density of states at the Fermi energy.

For this purpose, the width of the spectrum, i.e. the energetic distance between the insertion and Fermi edges, must be determined as precisely as possible. The work function of the surface to be examined then results from the difference between the photon energy and the width of the spectrum. In the example in Figure 8, a work function of 4.4 eV results for a 50 nm thick silver film on glass.

Figure 8: Determination of the work function of a 50 nm thick silver film on glass. The work function results from the difference between the photon energy and the width of the spectrum between the input and Fermi edges.

Your contact for XPS:

ICAN - Interdisciplinary Center for Analytics on the Nanoscale

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Functions

  • Wissenschaftliche/r Mitarbeiter/in, Center for Nanointegration Duisburg-Essen

The following publications are listed in the online university bibliography of the University of Duisburg-Essen. Further information may also be found on the person's personal web pages.

    Journal articles

  • Saddeler, Sascha; Hagemann, Ulrich; Bendt, Georg; Schulz, Stephan
    Core-shell Co₃O₄@CoO Nanoparticles for Enhanced OER Activity
    In: ChemCatChem (2024) in press
  • Sanjuán, Ignacio; Kumbhar, Vaibhav; Chanda, Vimanshu; Machado, Raíssa R. L.; Jaato, Bright N.; Braun, Michael; Mahbub, Muhammad A. A.; Bendt, Georg; Hagemann, Ulrich; Heidelmann, Markus; Schuhmann, Wolfgang; Andronescu, Corina
    Tunable Syngas Formation at Industrially Relevant Current Densities via CO₂ Electroreduction and Hydrogen Evolution over Ni and Fe-derived Catalysts obtained via One-Step Pyrolysis of Polybenzoxazine Based Composites
    In: Small (2024) in press
  • Placke-Yan, Carsten; Bendt, Georg; Salamon, Soma; Landers, Joachim; Wende, Heiko; Hagemann, Ulrich; Schulz, Stephan
    Versatile synthesis of sub-10 nm sized metal-doped MₓCo₃−ₓO₄ nanoparticles and their electrocatalytic OER activity
    In: Materials Advances (2024) CA Schulz in press
  • Luan, Chenglong; Corva, Manuel; Hagemann, Ulrich; Wang, Hongcai; Heidelmann, Markus; Tschulik, Kristina; Li, Tong
    Atomic-Scale Insights into Morphological, Structural, and Compositional Evolution of CoOOH during Oxygen Evolution Reaction
    In: ACS Catalysis Vol. 13 (2023) Nr. 2, pp. 1400 - 1411
  • Braun, Michael; Chatwani, Mohit; Kumar, Piyush; Hao, Yun; Sanjuán, Ignacio; Apostoleri, Ariadni-Aikaterini; Brix, Ann Cathrin; Morales, Dulce M.; Hagemann, Ulrich; Heidelmann, Markus; Masa, Justus; Schuhmann, Wolfgang; Andronescu, Corina
    Cobalt nickel boride as electrocatalyst for the oxidation of alcohols in alkaline media
    In: JPhys Energy Vol. 5 (2023) Nr. 2, 024005
  • Bera, Anupam; Bullert, Denise; Linke, Matthias; Franzka, Steffen; Hagemann, Ulrich; Hartmann, Nils; Hasselbrink, Eckart
    Interaction of 2-propanol with predominantly SrO- and TiO2-terminated SrTiO3(100) surfaces studied by vibrational sum frequency spectroscopy
    In: Catalysis Science and Technology Vol. 13 (2023) Nr. 17, pp. 4988 - 4995
  • Luan, Chenglong; Angona, Johanna; Bala Krishnan, Arjun; Corva, Manuel; Hosseini, Pouya; Heidelmann, Markus; Hagemann, Ulrich; Batsa Tetteh, Emmanuel; Schuhmann, Wolfgang; Tschulik, Kristina; Li, Tong
    Linking Composition, Structure and Thickness of CoOOH layers to Oxygen Evolution Reaction Activity by Correlative Microscopy
    In: Angewandte Chemie International Edition Vol. 62 (2023) Nr. 28, e202305982
  • Banko, Lars; Tetteh, Emmanuel Batsa; Kostka, Aleksander; Piotrowiak, Tobias Horst; Krysiak, Olga Anna; Hagemann, Ulrich; Andronescu, Corina; Schuhmann, Wolfgang; Ludwig, Alfred
    Microscale Combinatorial Libraries for the Discovery of High-Entropy Materials
    In: Advanced Materials Vol. 35 (2023) Nr. 9, 2207635
  • Wittmar, Alexandra; Vigneswaran, Thaarmikaa; Ranković, Nikola; Hagemann, Ulrich; Hartmann, Nils; Martínez-Hincapié, Ricardo; Čolić, Viktor; Ulbricht, Mathias
    N-Doped porous carbons obtained from chitosan and spent coffee as electrocatalysts with tuneable oxygen reduction reaction selectivity for H₂O₂ generation
    In: RSC Advances Vol. 13 (2023) Nr. 33, pp. 22777 - 22788
  • Leichtweis, Jandira; Carissimi, Elvis; Hagemann, Ulrich; Ulbricht, Mathias; Fischer, Lukas
    NiFe₂O₄/biochar decorated porous polymer membranes for the flow-through photo-Fenton degradation of tetracycline
    In: Chemical Engineering Journal Vol. 477 (2023) 147203
  • Fischer, Lukas; Volz, Anna; Hagemann, Ulrich; Ulbricht, Mathias
    Polymeric multi-composites with a tailored nickel microenvironment as catalytic flow-through membrane reactors for efficient p-nitrophenol degradation
    In: Chemical Engineering Journal Vol. 463 (2023) 142437
  • Wittmar, Alexandra S. M.; Ropertz, Marcus; Braun, Michael; Hagemann, Ulrich; Andronescu, Corina; Ulbricht, Mathias
    Preparation of N-doped carbon materials from cellulose:chitosan blends and their potential application in electrocatalytic oxygen reduction
    In: Polymer Bulletin Vol. 80 (2023) Nr. 7, pp. 7827 - 7845
  • Xiang, Weikai; Yang, Nating; Li, Xiaopeng; Linnemann, Julia; Hagemann, Ulrich; Ruediger, Olaf; Heidelmann, Markus; Falk, Tobias; Aramini, Matteo; DeBeer, Serena; Muhler, Martin; Tschulik, Kristina; Li, Tong
    3D atomic-scale imaging of mixed Co-Fe spinel oxide nanoparticles during oxygen evolution reaction
    In: Nature Communications Vol. 13 (2022) Nr. 1, 179
  • Dreyer, Maik; Hagemann, Ulrich; Heidelmann, Markus; Budiyanto, Eko; Cosanne, Nicolas; Friedel Ortega, Klaus; Najafishirtari, Sharif; Hartmann, Nils; Tüysüz, Harun; Behrens, Malte
    Beneficial Effects of Low Iron Contents on Cobalt‐Containing Spinel Catalysts in the Gas Phase 2‐Propanol Oxidation
    In: ChemCatChem Vol. 14 (2022) Nr. 18, e202200472
  • Dubey, Astita; Keat, Chin Hon; Shvartsman, Vladimir V.; Yusenko, Kirill V.; Escobar Castillo, Marianela; Buzanich, Ana Guilherme; Hagemann, Ulrich; Kovalenko, Sergey A.; Stähler, Julia; Lupascu, Doru C.
    Mono-, Di-, and Tri-Valent Cation Doped BiFe₀.₉₅Mn₀.₀₅O₃ Nanoparticles : Ferroelectric Photocatalysts
    In: Advanced Functional Materials Vol. 32 (2022) Nr. 43, 2207105
  • Brix, Ann Cathrin; Dreyer, Maik; Koul, Adarsh; Krebs, Moritz; Rabe, Anna; Hagemann, Ulrich; Varhade, Swapnil; Andronescu, Corina; Behrens, Malte; Schuhmann, Wolfgang; Morales, Dulce M.
    Structure-Performance Relationship of LaFe₁₋ₓCoₓO₃ Electrocatalysts for Oxygen Evolution, Isopropanol Oxidation, and Glycerol Oxidation
    In: ChemElectroChem Vol. 9 (2022) Nr. 4, e202200092
  • Thiemann, Fabian; Sciaini, G.; Kassen, A.; Hagemann, Ulrich; Meyer zu Heringdorf, Frank; Horn-von Hoegen, Michael
    Ultrafast transport-mediated homogenization of photoexcited electrons governs the softening of the A1g phonon in bismuth
    In: Physical Review B Vol. 106 (2022) Nr. 1, 014315
  • BalaKrishnan, Arjun; Blanc, Niclas; Hagemann, Ulrich; Gemagami, Parham; Wonner, Kevin; Tschulik, Kristina; Li, Tong
    Direct Detection of Surface Species Formed on Iridium Electrocatalysts during the Oxygen Evolution Reaction
    In: Angewandte Chemie International Edition Vol. 60 (2021) Nr. 39, pp. 21396 - 21403
  • Pollmann, Erik; Sleziona, Stephan; Foller, Tobias; Hagemann, Ulrich; Gorynski, Claudia; Petri, Oliver; Madauß, Lukas; Breuer, Lars; Schleberger, Marika
    Large-Area, Two-Dimensional MoS2 Exfoliated on Gold : Direct Experimental Access to the Metal–Semiconductor Interface
    In: ACS Omega Vol. 6 (2021) Nr. 24, pp. 15929 - 15939
  • Karlušić, Marko; Mičetić, Maja; Kresić, M.; Jakšić, Milko; Šantić, Branko; Bogdanović-Radović, Iva; Bernstorff, Sigrid; Lebius, Henning; Ban-d'Etat, Brigitte; Žužek Rožman, Kristina; O'Connell, Jacques; Hagemann, Ulrich; Schleberger, Marika
    Nanopatterning surfaces by grazing incidence swift heavy ion irradiation
    In: Applied Surface Science Vol. 541 (2021) pp. 148467
  • Omambac, Karim; Petrović, Marin; Bampoulis, Pantelis; Brand, Christian; Kriegel, Marko A.; Dreher, Pascal; Janoschka, David; Hagemann, Ulrich; Hartmann, Nils; Valerius, Philipp; Michely, Thomas; Meyer zu Heringdorf, Frank; Horn-von Hoegen, Michael
    Segregation-Enhanced Epitaxy of Borophene on Ir(111) by Thermal Decomposition of Borazine
    In: ACS Nano Vol. 15 (2021) Nr. 4, pp. 7421 - 7429
  • Angel, Steven; Tapia, Juan David; Gallego, Jaime; Hagemann, Ulrich; Wiggers, Hartmut
    Spray-Flame Synthesis of LaMnO₃₊δNanoparticles for Selective CO Oxidation (SELOX)
    In: Energy & Fuels Vol. 35 (2021) Nr. 5, pp. 4367 - 4376
  • Dreyer, Maik; Cruz, Daniel; Hagemann, Ulrich; Zeller, Patrick; Heidelmann, Markus; Salamon, Soma; Landers, Joachim; Rabe, Anna; Friedel Ortega, Klaus; Najafishirtari, Sharif; Wende, Heiko; Hartmann, Nils; Knop-Gericke, Axel; Schlögl, Robert; Behrens, Malte
    The Effect of Water on the 2-Propanol Oxidation Activity of Co-Substituted LaFe₁−CoₓO₃ Perovskites
    In: Chemistry - A European Journal Vol. 27 (2021) Nr. 68: Special Issue: Contemporary Challenges in Catalysis, pp. 17127 - 17144
  • Rabe, Anna; Büker, Julia; Salamon, Soma; Koul, Adarsh; Hagemann, Ulrich; Landers, Joachim; Friedel Ortega, Klaus; Peng, Baoxiang; Muhler, Martin; Wende, Heiko; Schuhmann, Wolfgang; Behrens, Malte
    The Roles of Composition and Mesostructure of Cobalt-Based Spinel Catalysts in Oxygen Evolution Reactions
    In: Chemistry - A European Journal Vol. 27 (2021) Nr. 68, pp. 17038 - 17048
  • Madauß, Lukas; Pollmann, Erik; Foller, Tobias; Schumacher, Jens; Hagemann, Ulrich; Heckhoff, Tobias; Herder, Matthias; Skopinski, Lucia; Breuer, Lars; Hierzenberger, Anke; Wittmar, Alexandra; Lebius, Henning; Benyagoub, Abdenacer; Ulbricht, Mathias; Joshi, Rakesh; Schleberger, Marika
    A swift technique to hydrophobize graphene and increase its mechanical stability and charge carrier density
    In: npj 2D Materials and Applications Vol. 4 (2020) Nr. 1, 11
  • Naveed-Ul-Haq, M.; Shvartsman, Vladimir; Trivedi, Harsh; Salamon, Soma; Webers, Samira; Wende, Heiko; Hagemann, Ulrich; Schröder, Jörg; Lupascu, Doru C.
    Corrigendum to ‘Strong converse magnetoelectric effect in (Ba,Ca)(Zr,Ti)O₃-NiFe₂O₄ multiferroics: A relationship between phase-connectivity and interface coupling’ (Acta Materialia (2018) 144 (305–313), (S1359645417309072), (10.1016/j.actamat.2017.10.048))
    In: Acta Materialia Vol. 187 (2020) pp. 91 - 92
  • Alkan, Baris; Medina, Danea; Landers, Joachim; Heidelmann, Markus; Hagemann, Ulrich; Salamon, Soma; Andronescu, Corina; Wende, Heiko; Schulz, Christof; Schuhmann, Wolfgang; Wiggers, Hartmut
    Cover Feature: Spray‐Flame‐Prepared LaCo1–xFexO3 Perovskite Nanoparticles as Active OER Catalysts : Influence of Fe Content and Low‐Temperature Heating (ChemElectroChem 12/2020)
    In: ChemElectroChem Vol. 7 (2020) Nr. 12, pp. 2495 - 2495
  • Dubey, Astita; Escobar Castillo, Marianela; Landers, Joachim; Salamon, Soma; Wende, Heiko; Hagemann, Ulrich; Gemeiner, Pascale; Dkhil, Brahim; Shvartsman, Vladimir; Lupascu, Doru C.
    Effect of Mn and Ba Codoping on a Magnetic Spin Cycloid of Multiferroic Bismuth Ferrite Nanoparticles
    In: Journal of Physical Chemistry C: Nanomaterials and Interfaces Vol. 124 (2020) Nr. 40, pp. 22266 - 22277
  • Saddeler, Sascha; Hagemann, Ulrich; Schulz, Stephan
    Effect of the Size and Shape on the Electrocatalytic Activity of Co₃O₄Nanoparticles in the Oxygen Evolution Reaction
    In: Inorganic Chemistry Vol. 59 (2020) Nr. 14, pp. 10013 - 10024
  • Tigges, Sebastian; Wöhrl, Nicolas; Radev, Ivan; Hagemann, Ulrich; Heidelmann, Markus; Nguyen, Thai Binh; Gorelkov, Stanislav; Schulz, Stephan; Lorke, Axel
    One-step synthesis of carbon-supported electrocatalysts
    In: Beilstein Journal of Nanotechnology Vol. 11 (2020) pp. 1419 - 1431
  • Alkan, Baris; Medina, Danea; Landers, Joachim; Heidelmann, Markus; Hagemann, Ulrich; Salamon, Soma; Andronescu, Corina; Wende, Heiko; Schulz, Christof; Schuhmann, Wolfgang; Wiggers, Hartmut
    Spray-Flame-Prepared LaCo₁–ₓFeₓO₃ Perovskite Nanoparticles as Active OER Catalysts : Influence of Fe Content and Low-Temperature Heating
    In: ChemElectroChem Vol. 7 (2020) Nr. 12, pp. 2564 - 2574
  • Tigges, Sebastian; Wöhrl, Nicolas; Hagemann, Ulrich; Ney, Marcel; Lorke, Axel
    The effect of metal-oxide incorporation on the morphology of carbon nanostructures
    In: Journal of Physics D: Applied Physics Vol. 53 (2020) Nr. 14, pp. 145206
  • Kalus, Mark; Lanyumba, Riskyanti; Lorenzo-Parodi, Nerea; Jochmann, Maik; Kerpen, Klaus; Hagemann, Ulrich; Schmidt, Torsten Claus; Barcikowski, Stephan; Gökce, Bilal
    Correction : Determining the role of redox-active materials during laser-induced water decomposition
    In: Physical Chemistry, Chemical Physics (PCCP) Vol. 21 (2019) Nr. 43, pp. 24239
  • Kalus, Mark; Lanyumba, Riskyanti; Lorenzo-Parodi, Nerea; Jochmann, Maik; Kerpen, Klaus; Hagemann, Ulrich; Schmidt, Torsten Claus; Barcikowski, Stephan; Gökce, Bilal; Lorenzo Parodi, Nerea
    Determining the role of redox-active materials during laser-induced water decomposition
    In: Physical Chemistry, Chemical Physics (PCCP) Vol. 21 (2019) Nr. 34, pp. 18636 - 18651
  • Stanchik, A.V.; Gremenok, V.F.; Juskenas, R.; Tyukhov, I.I.; Tivanov, M.S.; Fettkenhauer, Ch.; Shvartsman, Vladimir; Giraitis, R.; Hagemann, Ulrich; Lupascu, Doru C.
    Effects of selenization time and temperature on the growth of Cu₂ZnSnSe₄ thin films on a metal substrate for flexible solar cells
    In: Solar Energy Vol. 178 (2019) pp. 142 - 149
  • Beyer, Christopher; Dohmen, Ralf; Rogalla, Detlef; Becker, Hans-Werner; Marquardt, Katharina; Vollmer, Christian; Hagemann, Ulrich; Hartmann, Nils; Chakraborty, Sumit
    Lead diffusion in CaTiO₃ : A combined study using Rutherford backscattering and TOF-SIMS for depth profiling to reveal the role of lattice strain in diffusion processes
    In: American Mineralogist Vol. 104 (2019) Nr. 4, pp. 557 - 568
  • Pappert, Kevin; Loza, Kateryna; Shviro, Meital; Hagemann, Ulrich; Heggen, Marc; Dunin-Borkowski, Rafal E.; Schierholz, Roland; Maeda, Takuya; Kaneko, Kenji; Epple, Matthias
    Nanoscopic Porous Iridium/Iridium Dioxide Superstructures (15 nm) : Synthesis and Thermal Conversion by In Situ Transmission Electron Microscopy
    In: Chemistry - A European Journal Vol. 25 (2019) Nr. 47, pp. 11048 - 11057
  • Haxhiaj, Ina; Tigges, Sebastian; Firla, Damian; Zhang, Xiaorui; Hagemann, Ulrich; Kondo, Takahiro; Nakamura, Junji; Marzun, Galina; Barcikowski, Stephan
    Platinum nanoparticles supported on reduced graphene oxide prepared in situ by a continuous one-step laser process
    In: Applied Surface Science Vol. 469 (2019) pp. 811 - 820
  • Speich, Claudia; Dissinger, Frank; Liborius, Lisa; Hagemann, Ulrich; Waldvogel, Siegfried R.; Tegude, Franz-Josef; Prost, Werner
    Process Development for Wet-Chemical Surface Functionalization of Gallium Arsenide Based Nanowires
    In: Physica Status Solidi (B): Basic Solid State Physics (2019) pp. 1800678
  • Ruks, Tatjana; Beuck, Christine; Schaller, Torsten; Niemeyer, Felix; Zähres, Manfred; Loza, Kateryna; Heggen, Marc; Hagemann, Ulrich; Mayer, Christian; Bayer, Peter; Epple, Matthias
    Solution NMR Spectroscopy with Isotope-Labeled Cysteine (¹³C and ¹⁵N) Reveals the Surface Structure of l -Cysteine-Coated Ultrasmall Gold Nanoparticles (1.8 nm)
    In: Langmuir Vol. 35 (2019) Nr. 3, pp. 767 - 778
  • Hagemann, Ulrich; Huba, Kornelia; Nienhaus, Hermann
    Measuring displacement currents during fabrication of Mg/Si Schottky diodes due to band-bending evolution
    In: Journal of Applied Physics Vol. 124 (2018) Nr. 22, pp. 225302
  • Naveed-Ul-Haq, M.; Shvartsman, Vladimir; Trivedi, Harsh; Salamon, Soma; Webers, Samira; Wende, Heiko; Hagemann, Ulrich; Schröder, Jörg; Lupascu, Doru C.
    Strong converse magnetoelectric effect in (Ba,Ca)(Zr,Ti)O3 - NiFe2O4 multiferroics : a relationship between phase-connectivity and interface coupling
    In: Acta Materialia Vol. 144 (2018) pp. 305 - 313
  • Bahners, Thomas; Gebert, Beate; Prager, Andrea; Hartmann, Nils; Hagemann, Ulrich; Gutmann, Jochen Stefan
    UV-light assisted patterned metallization of textile fabrics
    In: Applied Surface Science Vol. 436 (2018) pp. 1093 - 1103
  • Waag, Friedrich; Gökce, Bilal; Kalapu, Chakrapani; Bendt, Georg; Salamon, Soma; Landers, Joachim; Hagemann, Ulrich; Heidelmann, Markus; Schulz, Stephan; Wende, Heiko; Hartmann, Nils; Behrens, Malte; Barcikowski, Stephan
    Adjusting the catalytic properties of cobalt ferrite nanoparticles by pulsed laser fragmentation in water with defined energy dose
    In: Scientific Reports Vol. 7 (2017) Nr. 1, pp. 13161
  • Lau, Marcus; Straube, Thomas; Aggarwal, A. Vikas; Hagemann, Ulrich; De Oliveira Viestel, Bernardo; Hartmann, Nils; Textor, Torsten; Lutz, Harald; Gutmann, Jochen Stefan; Barcikowski, Stephan
    Gradual modification of ITO particle's crystal structure and optical properties by pulsed UV laser irradiation in a free liquid jet
    In: Dalton Transactions Vol. 46 (2017) Nr. 18, pp. 6039 - 6048
  • Schaumann, Julian; Loor, Manuel; Ünal, Deria; Mudring, Anja; Heimann, Stefan; Hagemann, Ulrich; Schulz, Stephan; Maculewicz, Franziska; Schierning, Gabi
    Improving the zT value of thermoelectrics by nanostructuring : Tuning the nanoparticle morphology of Sb2Te3 by ionic liquids
    In: Dalton Transactions Vol. 46 (2017) Nr. 3, pp. 656 - 668
  • Rytlewski, Piotr; Bahners, Thomas; Polewski, Filip; Gebert, Beate; Gutmann, Jochen Stefan; Hartmann, Nils; Hagemann, Ulrich; Moraczewski, Krzysztof
    Laser-induced surface activation of biocomposites for electroless metallization
    In: Surface and Coatings Technology Vol. 311 (2017) pp. 104 - 112
  • Petrović, Marin; Hagemann, Ulrich; Horn-von Hoegen, Michael; Meyer zu Heringdorf, Frank
    Microanalysis of single-layer hexagonal boron nitride islands on Ir(111)
    In: Applied Surface Science Vol. 420 (2017) pp. 504 - 510
  • Loor, Manuel; Bendt, Georg; Schaumann, Julian; Hagemann, Ulrich; Heidelmann, Markus; Wölper, Christoph; Schulz, Stephan
    Synthesis of Sb2Se3 and Bi2Se3 Nanoparticles in Ionic Liquids at Low Temperatures and Solid State Structure of [C4C1Im]3[BiCl6]
    In: Zeitschrift für Anorganische und Allgemeine Chemie (ZAAC) Vol. 643 (2017) Nr. 1, Special Issue: Reactions in Ionic Liquids, pp. 60 - 68
  • Daumann, S.; Andrzejewski, Dominik; Di Marcantonio, M.; Hagemann, Ulrich; Wepfer, Svenja; Vollkommer, F.; Bacher, Gerd; Epple, Matthias; Nannen, Ekaterina
    Water-free synthesis of ZnO quantum dots for application as an electron injection layer in light-emitting electrochemical cells
    In: Journal of Materials Chemistry C: Materials for Optical and Electronic Devices Vol. 5 (2017) Nr. 9, pp. 2344 - 2351
  • Fischer, Mathias; Hormes, Josef; Marzun, Galina; Wagener, Philipp; Hagemann, Ulrich; Barcikowski, Stephan
    In Situ Investigations of Laser-Generated Ligand-Free Platinum Nanoparticles by X-ray Absorption Spectroscopy : How Does the Immediate Environment Influence the Particle Surface?
    In: Langmuir Vol. 32 (2016) Nr. 35, pp. 8793 - 8802
  • Bendt, Georg; Schiwon, Raphael; Salamon, Soma; Landers, Joachim; Hagemann, Ulrich; Limberg, Christian; Wende, Heiko; Schulz, Stephan
    Molecular design for tailoring a single-source precursor for bismuth ferrite
    In: Inorganic Chemistry Vol. 55 (2016) Nr. 15, pp. 7542 - 7549
  • Schade, Linda; Franzka, Steffen; Thomas, Marc; Hagemann, Ulrich; Hartmann, Nils
    Resonant laser processing of nanoparticulate Au/TiO2 films on glass supports : Photothermal modification of a photocatalytic nanomaterial
    In: Surface Science Vol. 650 (2016) pp. 57 - 63
  • Loor, Manuel; Bendt, Georg; Hagemann, Ulrich; Wölper, Christoph; Assenmacher, Wilfried; Schulz, Stephan
    Synthesis of Bi2Te3 and (BixSb1−x)2Te3 nanoparticles using the novel IL [C4mim]3[Bi3I12]
    In: Dalton Transactions Vol. 45 (2016) Nr. 39, pp. 15326 - 15335
  • Xiao, Lisong; Schroeder, Matthias; Kluge, Sebastian; Balducci, Andrea; Hagemann, Ulrich; Schulz, Christof; Wiggers, Hartmut
    Direct self-assembly of Fe2O3/reduced graphene oxide nanocomposite for high-performance lithium-ion battery
    In: Journal of Materials Chemistry A: Materials for Energy and Sustainability Vol. 3 (2015) Nr. 21, pp. 11566 - 11574
  • Hagemann, Ulrich; Nienhaus, Hermann
    Surface plasmon coupled chemiluminescence during adsorption of oxygen on magnesium surfaces
    In: The Journal of Chemical Physics (JCP) Vol. 143 (2015) Nr. 24, pp. 244703
  • Bendt, Georg; Sonntag, Jens; Lorke, Axel; Assenmacher, Wilfried; Hagemann, Ulrich; Schulz, Stephan
    Van der Waals epitaxial MOCVD-growth of (BixSb1-x)2Te3 (0
    In: Semiconductor Science and Technology Vol. 30 (2015) Nr. 8, pp. 085021
  • Merk, Vivian; Rehbock, Christoph; Becker, Felix; Hagemann, Ulrich; Nienhaus, Hermann; Barcikowski, Stephan
    In situ non-DLVO stabilization of surfactant-free, plasmonic gold nanoparticles : effect of Hofmeister's anions
    In: Langmuir Vol. 30 (2014) Nr. 15, pp. 4213 - 4222
  • Hagemann, Ulrich; Nienhaus, Hermann
    Quantum size effects in chemicurrent measurements during low-temperature oxidation of Mg(0001) epilayers
    In: New Journal of Physics (NJP) Vol. 16 (2014) pp. 113035
  • Becker, Felix; Krix, David; Hagemann, Ulrich; Nienhaus, Hermann
    Internal detection of surface plasmon coupled chemiluminescence during chlorination of potassium thin films
    In: The Journal of Chemical Physics (JCP) Vol. 138 (2013) Nr. 3, pp. 034710-1 - 034710-6
  • Nienhaus, Hermann; Karacuban, Hatice; Krix, David; Becker, Felix; Hagemann, Ulrich; Steeger, Doris; Bywalez, Robert; Schulz, Christof; Wiggers, Hartmut
    Low temperature diffusion of Li atoms into Si nanoparticles and surfaces
    In: Journal of Applied Physics Vol. 114 (2013) Nr. 3, pp. 034310
  • Hagemann, Ulrich; Krix, David; Nienhaus, Hermann
    Electronic excitations generated by the deposition of Mg on Mg films
    In: Physical Review Letters Vol. 104 (2010) Nr. 2, pp. 028301
  • Hagemann, Ulrich; Timmer, Matthias; Krix, David; Kratzer, Peter; Nienhaus, Hermann
    Electronic excitations in magnesium epitaxy: Experiment and theory
    In: Physical Review B: Condensed matter and materials physics Vol. 82 (2010) Nr. 15, 155420-1-9
  • Thesis

  • Hagemann, Ulrich;
    Quantum size effects in Mg epilayers on Si (111) : enhancement of photoelectron yield and oxidation rate
    Duisburg, Essen (2015) 207 S.
  • Research report

  • Hagemann, Ulrich
    Angle Resolved XPS - ARXPS
    (2021)
    (ICAN Notes ; 3)
  • Hagemann, Ulrich
    Focus Track – How to minimize and compensate z-Axis drift using the Renishaw InVia Raman microscope
    (2021)
    (ICAN Notes ; 5)
  • Lectures

  • Deike, Rüdiger; Smaha, Bartosz; Müller, Ulrich; Hagemann, Ulrich; Heidelmann, Markus; Kiesler, Dennis;
    Neue Erkenntnisse zur Keimbildung bei GJS
    Österreichische Gießereitagung ; Gurten, 27.-28. April 2017,
    Gurten, Österreich (2017)