Dresden 2026 – scientific programme

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O: Fachverband Oberflächenphysik

O 95: 2D Materials: Stacking and heterostructures (joint session O/HL/TT)

O 95.12: Talk

Friday, March 13, 2026, 12:15–12:30, HSZ/0401

STEM Investigation of Entropy Forbidden Ordering in CVD Grown WSe₂-MoSe₂ Alloys — •Max Bergmann¹, Matvei Kislitsyn¹, Julian Picker², Jürgen Belz¹, Robin Günkel¹, Badrosadat Ojaghi Dogahe¹, Shamail Ahmed¹, Andrey Turchanin², and Kerstin Volz¹ — ¹mar.quest | Marburg Center for Quantum Materials and Sustainable Technologies, Philipps-Universität Marburg, 35032 Marburg, Germany — ²Faculty of Chemistry and Earth Sciences, Friedrich-Schiller-Universität, 07743 Jena, Germany

2D transition metal dichalcogenides have gained significant interest due to their optoelectronic properties, which can be tailored by structural variation. However, controllable production, namely growth, of such tailored structures still remains a key challenge towards large-scale production. In this study, we show lateral heterostructures of 2D MoSe₂ and WSe₂, grown on a SiO₂ TEM grid by chemical vapor deposition, that at the interface show a highly ordered structure of W and Mo atoms at the TMD positions, as observed by scanning transmission electron microscopy. This is in contrast to ab initio calculations, which ascribe unordered alloys as the preferred configuration, since entropy is the main driving force compared to formation enthalpy. We link this unexpected phenomenon to the initial nucleation of the material on a clean MoSe₂ crystal edge, present before the alloy growth, together with special precursor chemistry. Furthermore, we show ab initio results in conjunction with the special quasirandom structure method on the bandstructure and optical properties of this structure.

Keywords: 2D Heterostructure; Ordering; STEM; CVD; TMDs