Dresden 2014 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 121: Graphene (organized by DS)
HL 121.7: Vortrag
Freitag, 4. April 2014, 13:00–13:15, CHE 89
Tuning of structural, electronic and optical properties in twisted bilayer MoS2 — •Jens Kunstmann1, Arend M. van der Zande1, Alexey Chernikov1, Daniel A. Chenet1, YuMeng You1, XiaoXiao Zhang1, Timothy C. Berkelbach1, Pinshane Y. Huang2, Lei Wang1, Fan Zhang1, Mark Hybertsen1,3, David A. Muller2, David R. Reichman1, Tony F. Heinz1, and James C. Hone1 — 1Columbia University, New York, New York, 10027, USA — 2Cornell University, Ithaca, New York, 14853, USA — 3Brookhaven National Laboratory, Upton, New York 11973, USA
With the rise of graphene, atomically thin 2D materials have become the focus of many researchers worldwide. Among them, group 6 transition metal dichalcogenides, such as MoS2 are new 2D direct gap semiconductors, have been used as field effect transistors and are promising for applications in valleytronics. However, little is understood about the interlayer interactions between 2D materials. We measured dozens of MoS2 bilayers with well-defined twist angle by stacking single crystal monolayers using ultraclean transfer techniques. We observe that continuous changes in the interlayer twist angle lead to strong, continuous tuning in the indirect optical transitions, the Raman modes, the second harmonic generation, and the reflection spectra. We use electronic structure calculations to show that the tuning in the indirect band transitions arise from an increase of the bilayer separation caused by the van der Waals repulsion of sulfur atoms. These results indicate the possibility of producing new 2D materials with desired properties by tailoring the interlayer alignment in 2D heterostructures.