Berlin 2015 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 73: Graphene: Structure (O with HL/TT)
HL 73.4: Vortrag
Donnerstag, 19. März 2015, 11:15–11:30, MA 041
A route to free-standing graphene by removal of the Ni substrate by a gas phase reaction — •Ann-Kathrin Henß1, Patrick Zeller1, Michael Weinl2, Matthias Schreck2, and Joost Wintterlin1 — 1Ludwig-Maximilians-Universität, Munich, Germany — 2Universität Augsburg, Augsburg, Germany
An essential step for the use of graphene in electronic devices is the removal of the underlying metal substrate after graphene growth. We have tested a new route to free-standing graphene grown on thin single crystalline Ni(111) films. The 150 nm thick metal films were epitaxially grown on a Si(111) wafer separated by a 120 to 150 nm thick yttria-stabilized zirconia (YSZ) buffer layer. Aligned monolayer graphene was grown by chemical vapor deposition using ethylene as precursor gas under ultra high vacuum conditions. The graphene quality was monitored by scanning tunneling microscopy and low energy electron diffraction. The subsequent removal of the nickel substrate was performed in a pure gas phase reaction. In the so called Mond process, a chemical transport reaction, nickel reacts with carbon monoxide to gaseous nickel tetracarbonyl at 350 K. By applying a temperature gradient in the reaction furnace the formed carbonyl complex is transported to areas with higher temperature leaving graphene on the isolating YSZ buffer layer of the substrate. X-ray photoelectron spectroscopy, scanning electron microscopy and Raman spectroscopy were used to study the samples after this process.