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HL: Fachverband Halbleiterphysik

HL 48: Two-dimensional Materials IV (joint session HL/CPP)

HL 48.1: Vortrag

Freitag, 5. April 2019, 09:30–09:45, H36

Optical Valleytronic Properties of CVD-grown Tungsten Disulfide AA' and AB Bilayers — •Lorenz Maximilian Schneider¹, Jan Kuhnert¹, Simon Schmitt¹, Ulrich Huttner¹, Lars Meckbach¹, Tineke Strouken¹, Stepan W. Koch¹, Wolfram Heimbrodt¹, Shichen Fu², Xiaotian Wang², Kyung Nam Kang², and Arash Rahimi-Iman¹ — ¹Faculty of Physics and Materials Sciences Center, Philipps-Universität Marburg, D-35032 Marburg, Germany — ²Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, New Jersey, 07030, USA

Two-dimensional semiconductors such as transition-metal dichalcogenides have attracted considerable attention due to their strong light-matter interaction as well as "valleytronic" properties. The valley-dependent polarization properties are of potential interest for future devices and, both, homojunctions as well as heterostructures of monolayer materials promise considerable valley-polarization degrees and valley coherence.

In this work, chemical-vapour-deposition-grown AA' and AB stacked tungsten-disulfide bilayers are investigated. The differences between AA' and AB stacked bilayers are characterized optically and attributed to the distinct interlayer coupling between k-space valleys. Our spectroscopic investigations are supported by calculations focusing on the difference in symmetry and interlayer electronic coupling for these bilayers. A comparably high valley polarization and valley coherence is found for the AB stacked case in contrast to the AA' case, which is in good agreement with the expectations.