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Updated: Aug 16, 2025
Ohmic Contact Fabrication Using a Focused-ion Beam Technique and Electrical Characterization for Layer Semiconductor Nanostructures
Published on: December 5, 2015
Non-Additive Optical Response in Transition Metal Dichalcogenides Heterostructures
Marwa A El-Sayed1,2, Andrey P Tselin1,3, Georgy A Ermolaev1
1Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, 9 Institutsky Lane, Dolgoprudny 141700, Russia.
Abstract:
Van der Waals (vdW) heterostructures pave the way to achieve the desired material properties for a variety of applications. In this way, new scientific and industrial challenges and fundamental questions arise. One of them is whether vdW materials preserve their original optical response when assembled in a heterostructure. Here, we resolve this issue for four exemplary monolayer heterostructures: MoS2/Gr, MoS2/hBN, WS2/Gr, and WS2/hBN. Through joint Raman, ellipsometry, and reflectance spectroscopies, we discovered that heterostructures alter MoS2 and WS2 optical constants. Furthermore, despite the similarity of MoS2 and WS2 monolayers, their behavior in heterostructures is markedly different. While MoS2 has large changes, particularly above 3 eV, WS2 experiences modest changes in optical constants. We also detected a transformation from dark into bright exciton for MoS2/Gr heterostructure. In summary, our findings provide clear evidence that the optical response of heterostructures is not the sum of optical properties of its constituents.
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