Berlin 2015 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 73: Graphene: Structure (O with HL/TT)
HL 73.6: Vortrag
Donnerstag, 19. März 2015, 11:45–12:00, MA 041
Graphene Membranes as Electron Transparent Windows for Photoelectron Spectroscopy — •Jürgen Kraus1, Robert Reichelt1, Sebastian Günther1, Luca Gregoratti2, Matteo Amati2, Maya Kiskinova2, Alexander Yulaev4, Ivan Vlassiouk3, and Andrei Kolmakov4 — 1TU München Chemie Department, Lichtenbergstr. 4, D-85748 Garching — 2Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy — 3Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA — 4Center for Nanoscale Science and Technology, NIST, Gaithersburg, MD 20899, USA
The high mechanical stability of graphene (g) allows the construction of ultrathin gas tight membranes. Transferred few layer thick g covering the orifice of an environmental cell could be used to seal a water droplet inside the cell from the surrounding vacuum of the ultra-high vacuum chamber into which the cell was introduced. The used membranes were transparent even for slow photoelectrons (PEs), so that the sealed water could be characterized by x-ray photoelectron spectroscopy (XPS). We also measured the electron attenuation length of monolayer g on Cu for PEs of 200-1000 eV kinetic energy. We were able to produce free standing monolayer g by locally electrochemically etching the Cu-substrate underneath the as-grown g. After deposition of gold on the membrane backside and acquiring Au 4f PEs from the opposite site, we proved that < 1% of a monolayer Au can be detected through the suspended g membrane. This pushes the applicability of our membrane based XPS technique towards surface characterization under ambient conditions.