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SFB1238 | Ursula Wurstbauer

On 08 May at 14:30 - 15:30 in Seminar Room of the Institute of Physics II

Ursula Wurstbauer, Universität Münster

 

Light matter interaction in tunable 2D materials and artificial van der Waals solids

 

Atomically thin two-dimensional layered materials receive great interest because of their unique properties. Particularly, monolayers of semiconducting transition metal dichalcogenides (SC-TMDs), such as MoS2, excel due to their strong light-matter interaction that is dominated by exciton phenomena [1-3]. Key to the integration of SC-TDM and related artificial van der Waals solids into circuitries is the possibility to tune and engineer their properties on demand and on-chip e.g. by defects, dielectric environment or doping [4-8].

We apply inelastic light scattering together with emission and absorption to study the manifold coupling mechanism in van der Waal hetero- and hybrid structures. We introduce the influence of the dielectric environment, the charge carrier density as well as defects on the optical properties of these atomically thin materials. Moreover, interlayer excitons (IX) in vdW hetero-bilayers are intriguing systems to explore classical and quantum phases of interacting bosonic ensembles due to their enhanced lifetimes. We observe multiplet IX emission lines for MoSe2/WSe2 and MoS2/WS2 hetero-bilayers that are interpreted in terms of multi-valley excitons [3, 9]. All-2D stark effect devices allows for the manipulation of the excitons by external electric fields [9]. Our results provide fundamental insights into long-lived interlayer states in van der Waals heterostructures with possible bosonic many-body interactions.

 

We acknowledge support by the Deutsche Forschungsgemeinschaft (DFG) via excellence cluster Nanosystems Initiative Munich (NIM), e-conversion as well as DFG project WU 637/4-1.

 

[1] U. Wurstbauer, et al. J. Phys. D: Appl. Phys. 50, 173001 (2017).

[2] S. Funke, et al., J. Phys.: Condens. Matter 28, 385301 (2016).

[3] B. Miller, et al., Nano Lett. 17(9), 5229–5237 (2017).

[4] E. Parzinger, et al., Nature 2D material 1, 40 (2017).

[5] S. Diefenbach, et al., J. Phys. Chem. C, 122 (17), 9663–9670 (2018).

[6] J. Klein, et al., 2D Materials 5, 011007 (2018), J. Klein et al., arXiv:1901.01042 (2019).

[7] B. Miller, et al., Appl. Phys. Lett. 106, 122103 (2015).

[8] B. Miller et al. Nature Commun. 10, 807 (2019).

[9] J. Kiemle et al. arXiv:1901.01042 (2019).

 

Contact Person: Alexander Grüneis