Work in progress

Currently at the Interdisciplinary Center for Analytics on the Nanoscale ICAN.

In the cause of my PhD Thesis I mainly work on the subject of chemicurrents. To be more precise, I study the reaction of gas molecules with epitaxial metal films in ultra high vacuum. This sounds rather simple, but in fact the growth of homogenous, epitaxial, large area metal (mostly Magnesium) films on a semiconducting substrate is far from it.

We need to achieve a high quality for the cristallinity of the metal film as well as a well functioning diodic character of the metal/semiconductor interface; two qualities that are not that easy to combine. We control the quality of the filmgrowth and the electronic properties of the diode with XPS, UPS, Auger, LEED and CV measurements.

These crystalline films show very intersting quantum size effects, for example an extremly intense electron emission from decaying plasmons during illumination with UV light.

During the final chemicurrent measurements we control the gas flow onto the sample by means of simple background filling of our UHV chamber with the gas in question or by using our newly setup, homebuild molecular beam chamber.

Other research interests are the character- and functionalization of nanoparticles in cooperation with different groups, Physics, Chemistry and Ingeneering, within CeniDE.

Curriculum vitae

Born in Best (Netherlands), school education in Essen (Germany).

Scientific Publications

Resonant laser processing of nanoparticulate Au/TiO2 films on glass supports: Photothermal modification of a photocatalytic nanomaterial
Lina Schade, Steffen Franzka, Ulrich Hagemann, Nils Hartmann, Surface Science, published online 15 January 2016

Surface plasmon coupled chemilumescence during adsorption of oxygen on magnesium surfaces
Ulrich Hagemann and Hermann Nienhaus, Journal of Chemical Physics 143, (2015) 244703.

Van der Waals epitaxial MOCVD-growth of (BixSb1−x)2Te3 (0 < x < 1) films
G. Bendt, J. Sonntag, A. Lorke, W. Assenmacher, U. Hagemann and S. Schulz, Semiconductor Science and Technology 30 (8), (2015), 085021.

Direct self-assembly of Fe2O3/reduced graphene oxide nanocomposite for high-performance lithium-ion batteries
Lisong Xiao, Matthias Schroeder, Sebastian Kluge, Andrea Balducci, Ulrich Hagemann, Christof Schulz and Hartmut Wiggers, Journal of Materials Chemistry A 3 (21), (2015), 11566.

Quantum size effects in Mg epilayers on Si(111): Enhancement of photoelectron yield and oxidation rate
Ulrich Hagemann, PhD Thesis, University of Duisburg-Essen, 2014.

Quantum size effects in chemicurrent measurements during low-temperature oxidation of Mg(0001) epilayers
Ulrich Hagemann and Hermann Nienhaus, New Journal of Physics 16 (2014) 113035.

In Situ Non-DLVO Stabilization of Surfactant-Free, Plasmonic Gold Nanoparticles: Effect of Hofmeister’s Anions
Vivian Merk, Christoph Rehbock, Felix Becker, Ulrich Hagemann, Hermann Nienhaus, Stephan Barcikowski, Langmuir 30 (15) (2014) 4213 - 4222.

Low temperature diffusion of Li atoms into Si nanoparticles and surfaces
H. Nienhaus, H. Karacuban, D. Krix, F. Becker, U. Hagemann, D. Steeger, R. Bywalez, C. Schulz, H. Wiggers, Journal of Applied Physics 114 (2013) 034310.

Internal detection of surface plasmon coupled chemiluminescence during chlorination of potassium thin films
F. Becker, D. Krix, U. Hagemann, H. Nienhaus, Journal of Chemical Physics 138, 3 (2013) 034710.

Electronic excitations generated by the deposition of Mg on Mg films,
U. Hagemann, D. Krix, and H. Nienhaus, Phys. Rev. Lett. 104 (2010) 028301.

Electronic excitations in magnesium epitaxy: Experiment and theory,
U. Hagemann, M. Timmer, D. Krix, P. Kratzer and Hermann Nienhaus, Phys. Rev. B 82, 15 (2010) 155420.