Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 48: Oxide and Insulator Surfaces: Structure, Epitaxy and Growth
O 48.5: Poster
Dienstag, 21. März 2017, 18:30–20:30, P1A
Electric field induced desorption of oxygen adatoms from the MoO2+x/Mo(110) surface — •Killian Walshe1, Sergey I. Bozhko2, Olaf Lübben1, Brian Walls1, Barry E. Murphy1, and Igor V. Shvets1 — 1Trinity College Dublin, Dublin, Ireland — 2Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow District 142432, Russia
Nanoscale writing on the MoO2+x/Mo(110) surface has been demonstrated previously by Krasnikov et al. [1]. Pulsing with the scanning tunneling microscopy (STM) tip leads to the removal of oxygen adatoms. Here, in the zero tunneling current regime, STM measurements illustrate how the resolution of the nanoscale writing depends on the applied bias voltage and tip-surface distance. STM measurements and the theoretical modelling (COMSOL Multiphysics) of the electric field generated between the STM tip and metallic surface provides insight into the mechanism behind this process; the electric field generated by a negatively biased STM tip leads to anion oxygen adatoms penetrating the surface. The energetic barrier for this process has been estimated to be 0.45 eV. Density functional theory (DFT) calculations [1] demonstrate that the oxygen adatoms locally deform the underlying molybdenum oxide structure. It is suggested that this deformation, which leaves a gap below the oxygen adatom, reduces the barrier for the adatom to penetrate the surface.
1. A. Krasnikov et al., Nano Res. 2013, 6(12), 929-937