Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 18: Semiconductor Substrates: Structure, Epitaxy and Growth
O 18.6: Vortrag
Montag, 20. März 2017, 17:15–17:30, WIL C307
Atomic scale STM and nc-AFM study of the Hematite (012) surface — •Zdenek Jakub1, Florian Kraushofer1, Magdalena Bichler2, Jan Hulva1, Martin Setvin1, Michael Schmid1, Ulrike Diebold1, Peter Blaha2, and Gareth. S. Parkinson1 — 1Institute of Applied Physics, TU Wien, Austria — 2Institute of Materials Chemistry, TU Wien, Austria
For its abundance, low cost, stability and environmental benignity, hematite (α-Fe2O3) is a promising material for utilization in a wide range of fields, including as a photoanode for photoelectrochemical water splitting [1]. Although (012) is known to be one of the most stable surfaces of hematite, the atomic-scale structure remains unknown. Here we present the first-ever atomic-scale scanning tunneling microscopy (STM) and non-contact atomic force microscopy (nc-AFM) study of the surface. Our data suggests that a bulk termination model for the oxidized (1x1) surface is plausible, but images of the reduced (2x1) surface are inconsistent with any of the previously proposed structural models. Based on the experimental data we propose a new model for the (2x1), whose plausibility is supported by our DFT calculations. We also present the results of H2O adsorption studies on the (2x1) surface and discuss the data in the context of previously published results [2].
[1] Parkinson, G.S., Surface Science Reports, 71, 272-365 (2016).
[2] Henderson, M.A. et al.. Surface Science, 417, 66-81 (1998).