Thickness determination of MoS2, MoSe2, WS2 and WSe2 on transparent stamps used for deterministic transfer of 2D materials

Abstract

Here, we propose a method to determine the thickness of the most common transition metal dichalcogenides (TMDCs) placed on the surface of transparent stamps, used for the deterministic placement of two-dimensional materials, by analyzing the red, green and blue channels of transmission-mode optical microscopy images of the samples. In particular, the blue channel transmittance shows a large and monotonic thickness dependence, making it a very convenient probe of the flake thickness. The method proved to be robust given the small flake-to-flake variation and the insensitivity to doping changes of MoS2. We also tested the method for MoSe2, WS2 and WSe2. These results provide a reference guide to identify the number of layers of this family of materials on transparent substrates only using optical microscopy.

4 figures in main text, 2 figures in supp. info

References in corpus (9)

• Electric Field Effect in Atomically Thin Carbon Films
• 2D materials and van der Waals heterostructures
• Boron nitride substrates for high-quality graphene electronics
• Anomalous Lattice Vibrations of Single and Few-Layer MoS2
• Phonon and Raman scattering of two-dimensional transition metal dichalcogenides from monolayer, multilayer to bulk material
• Recent progress in the assembly of nanodevices and van der Waals heterostructures by deterministic placement of 2D materials
• Fast pick up technique for high quality heterostructures of bilayer graphene and hexagonal boron nitride
• Micro-reflectance and transmittance spectroscopy: a versatile and powerful tool to characterize 2D materials
• Gate Tunable Photovoltaic Effect in MoS2 vertical P-N Homostructures

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