Berlin 2024 – scientific programme

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O: Fachverband Oberflächenphysik

O 29: Poster: 2D Materials

O 29.4: Poster

Tuesday, March 19, 2024, 12:30–14:30, Poster A

Growth of two-dimensional hexagonal β-GeSe on Au(111) — •Dina Wilks, Veronika Blecker, Marina Hammer, Muhammad Ali Martuza, Paulus Aleksa, and Carsten Busse — Department Physik, Universität Siegen, Walter-Flex-Straße 3, 57072 Siegen

Two-dimensional group-IV monochalcogenides (general form MX with M=Sn, Ge; X=S, Se, Te) have great potential in nanotechnology due to their versatility. Theory predicts several polymorphs of these materials. For GeSe none of these have been confirmed experimentally, unlike SnSe, SnS, and SnTe.
We report the first experimental realization of β-GeSe which has a corrugated honeycomb structure. The monolayers are prepared under highly controlled conditions (molecular beam epitaxy from GeSe powder on a single crystalline Au(111) substrate under ultra-high vacuum (UHV) conditions). We find a temperature window for self-limiting monolayer growth. Low-energy electron diffraction (LEED) reveals a (5 × 5) superstructure with respect to Au(111). For sub-monolayer coverage, we find orientational disorder while the full layer is highly aligned with respect to the sample. Scanning tunneling microscopy (STM) shows that a superstructure unit cell contains (4 × 4) β-GeSe unit cells. The Au(111) herringbone reconstruction is lifted under the MX-monolayer.

Keywords: Group-IV monochalcogenides; LEED; STM; GeSe; Au(111)