Probing Polymorphic Stacking Domains in Mechanically Exfoliated Two-Dimensional Nanosheets Using Atomic Force...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Stacking order is a critical factor in two-dimensional (2D) layered materials, influencing interlayer interactions and electronic properties.
• Polymorphic stacking domains in transition metal dichalcogenides (TMDCs) can affect material performance.
• Understanding stacking order is crucial for tuning the optoelectronic properties of 2D materials.

Purpose of the Study:

• To systematically investigate the effect of stacking order on interlayer interactions and electrostatic screening in few-layer molybdenum disulfide (MoS2) and molybdenum diselenide (MoSe2) nanosheets.
• To establish ultralow-frequency (ULF) Raman spectroscopy and electrostatic force microscopy (EFM) as effective tools for characterizing stacking order in 2D materials.
• To explore the correlation between stacking order and the optoelectronic properties of TMDC nanosheets.

Main Methods:

• Utilized ultralow-frequency (ULF) Raman spectroscopy to identify and confirm polymorphic stacking domains.
• Employed high-resolution atomic force microscopy (HR-AFM) to visualize atomic lattice arrangements and stacking differences.
• Applied electrostatic force microscopy (EFM) phase imaging to map the distribution of stacking domains and investigate electrostatic screening.

Main Results:

• Stacking order differences in MoS2 and MoSe2 nanosheets were successfully confirmed by ULF Raman spectroscopy and HR-AFM.
• EFM phase imaging effectively revealed the spatial distribution of polymorphic stacking domains.
• The study suggests that EFM, combined with ULF Raman spectroscopy, provides a rapid and high-resolution method for probing stacking domains in 2D TMDCs.

Conclusions:

• EFM and ULF Raman spectroscopy are powerful, complementary techniques for characterizing stacking order in 2D TMDCs.
• The findings provide a foundation for correlating interlayer interactions, stacking order, and optoelectronic properties in 2D materials.
• This research offers a promising approach for the controlled engineering of TMDC properties through stacking order manipulation.