Facile and Reliable Thickness Identification of Atomically Thin Dichalcogenide Semiconductors Using Hyperspectral...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Mechanical exfoliation is crucial for researching novel 2D materials like transition metal dichalcogenides (TMDCs).
• Identifying flakes of specific thicknesses from exfoliated samples is a time-consuming challenge.
• Existing characterization methods like Raman spectroscopy and atomic force microscopy can be destructive or slow.

Purpose of the Study:

• To develop a rapid, non-destructive method for determining the thickness of few-layer 2D materials.
• To facilitate the in-situ searching of 2D material flakes with desired thicknesses.
• To extend the technique for analyzing tin dichalcogenides (SnS2, SnSe2).

Main Methods:

• Utilizing hyperspectral wide-field microscopy to capture differential reflectance and transmittance spectra.
• Analyzing excitonic resonance features for unambiguous material and thickness identification.
• Developing an algorithm for automated searching of flakes based on optical contrast.

Main Results:

• Demonstrated single-step, non-destructive thickness determination for typical TMDCs.
• Successfully applied the method to tin dichalcogenides (SnS2, SnSe2), observing unique layer-dependent excitonic features.
• Validated an algorithm for in-situ, automated flake selection.

Conclusions:

• Hyperspectral microscopy offers a fast and non-destructive approach for characterizing 2D material thickness.
• The developed technique is suitable for quality control and mass production in the semiconductor industry.
• This method advances the characterization of van der Waals materials, including indirect bandgap semiconductors.