SKM 2023 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 28: Organic Molecules on Inorganic Substrates III: Adsorption and Growth I

O 28.6: Vortrag

Dienstag, 28. März 2023, 11:45–12:00, CHE 89

Adsorption of a Cyclic (Alkyl)(Amino)Carbene on Si(111)(√3×√3)R30^∘-B: Influence of the Defect Density — •Robert Zielinski¹, Mowpriya Das², Canan Kosbab¹, Mike Thomas Nehring¹, Mario Dähne¹, Norbert Esser^1,3, Martin Franz¹, and Frank Glorius² — ¹Institut für Festkörperphysik, Technische Universität Berlin, Berlin, Deutschland — ²Westfälische Wilhelms-Universität Münster, Organisch-Chemisches Institut, Münster, Deutschland — ³Leibniz-Institut für Analytische Wissenschaften - ISAS e.V., Berlin, Germany

N-Heterocyclic carbenes (NHCs) have been shown to be excellent modifiers and anchors for the functionalization of surfaces, but so far mostly on metals. Thus a controlled functionalization of semiconductor surfaces by ordered NHC layers is of great interest. In the present work we investigate the adsorption behavior of cyclohexyl cyclic (alkyl)(amino)carbene (cyCAAC) molecules on the Si(111)(√3×√3)R30^∘-B surface using scanning tunneling microscopy and X-ray photoelectron spectroscopy. We find a self-limited, well-ordered growth of a stable monolayer with large domains characterized by a 3×3 periodicity and an upright adsorption geometry of the molecules. A strong correlation between the domain size and the substrate defect density is found, revealing that the initial molecular adsorption preferentially takes place on a particular type of surface defect. Work function measurements of the cyCAAC monolayer reveal a large reduction of work function.