Regensburg 2022 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 42: 2D Materials 6 (joint session HL/CPP/DS)

HL 42.3: Talk

Friday, September 9, 2022, 10:00–10:15, H36

Atomic layer deposition of ternary MoWS₂ — •Christian Tessarek, Tim Grieb, Andreas Rosenauer, and Martin Eickhoff — Institut für Festkörperphysik, Universität Bremen

Two-dimensional (2D) monolayers of binary molybdenum disulfide (MoS₂) and tungsten disulfide (WS₂) belong to the transition metal dichalcogenide (TMDC) material family and are direct band gap semiconductors. The optical band gap of monolayer MoS₂ and WS₂ is ∼1.9 and 2.0 eV, respectively. Ternary Mo_xW_1−xS₂ enables tuning of excitonic transition energy dependent on the concentration x.

Atomic layer deposition (ALD) is used to deposit MoWS₂ in the whole composition range between pure MoS₂ and WS₂. The concentration x is determined by the frequency position of the A_1g Raman mode. The distribution of W and Mo atoms in the crystal lattice of MoWS₂ is studied by high resolution scanning transmission electron microscopy. Additional annealing is performed to improve structural and optical properties. Photoluminescence spectroscopy measurements show concentration dependent spectral position of A and B excitonic emission.