Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 23: Poster Monday: Nanostructures 1

O 23.7: Poster

Montag, 5. September 2022, 18:00–20:00, P4

On-surface synthesis of narrow porous graphene nanoribbons — Christoph Dobner¹, Mamun Sarker², •Adrian Ebert¹, Alexander Sinitskii², and Axel Enders¹ — ¹Physikalisches Institut, Universität Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany — ²Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE68588, USA

Fueled by the technological necessity to induce semiconducting properties in graphenic nanostructures, the search for strategies to manipulate their electronic properties has become an active field of research. Common control parameters that determine the band gap of graphene nanoribbons (GNR) are structural width, edge design and heteroatom doping. It has also been theoretically predicted that periodic vacancies can open up a band gap in to otherwise semimetallic 2D-graphene sheets. It is thus reasonable to expect that porosity could also contribute to the band structure of already semiconducting GNRs. In this work we present a strategy for the on-surface synthesis of porous GNRs using precursor. We will show that modified halogenation sites on the precursor molecules result in GNRs containing a periodic arrangement of vacancies along the ribbons backbones. Tunneling spectroscopy was used to determine the band edge locations and band gap width of such structures, revealing a increased band gap of 1.96 eV. Additional dI/dV mapping revealed that periodic electronic states are located at the edges and inside the backbone, induced by the porosity of the structures. Based on these findings a route towards considerably wider porous graphenic flakes will be discussed.