Regensburg 2019 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 61: Semiconductor Surfaces: Adsorption and Reactivity
O 61.7: Vortrag
Mittwoch, 3. April 2019, 16:30–16:45, H25
Electronic and Field Induced Manipulation of Diethyl Ether on Si(001) — •Tamam Bohamud1, Alexa Adamkiewicz1, Marcel Reutzel1, Michael Dürr1,2, and Ulrich Höfer1 — 1Philipps-Universität, 35037 Marburg — 2Justus-Liebig-Universität Giessen, 35392 Giessen
Scanning tunneling microscopy is an effective tool to manipulate single atoms and molecules on surfaces. Typical excitation processes involved are direct electronic excitation or vibrational excitation via inelastic tunneling. Here we show for diethyl ether fragments on Si(001) that, depending on the tunneling bias, both direct excitation as well as field-induced hopping of the molecular fragments can be observed.
Adsorption of diethyl ether on Si(001) leads to covalently bound ethoxy and ethyl entities on the surface[1]. At room temperature, tip-induced hopping of the ethyl entity on one dimer is observed at relatively low tunneling bias. For this process, no dependence on the tunneling current is observed. On the other hand, for the same parameters but at 50 K surface temperature, no such tip-induced hopping is observed at all. We interpret these experimental results in terms of a field-assisted, thermally activated hopping process. At increased bias voltage, hopping events along the dimer rows were also observed. For this process, a linear dependence of the hopping rate on the tunneling current indicates a direct electronic excitation as origin of the tip-induced hopping process.
[1] M. Reutzel et al., J. Phys. Chem. C. 119, 6018(2015).