Spectroscopic Analysis on Different Stacking Configurations of Multilayered MoSe₂

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Transition metal dichalcogenides (TMDs) exhibit unique photoelectric properties influenced by their layer number.
• Achieving controlled layers and high quality in TMDs remains a significant challenge in materials science.

Purpose of the Study:

• To develop a method for growing layer-controlled, high-quality multilayered molybdenum diselenide (MoSe2) flakes.
• To characterize the optoelectronic properties and stacking order of MoSe2 sheets using advanced spectroscopic techniques.

Main Methods:

• Salt-assisted chemical vapor deposition (CVD) was employed to synthesize multilayered MoSe2.
• Characterization involved Raman spectroscopy, second harmonic generation (SHG), and photoluminescence (PL).
• Spectroscopic mapping was used to assess film quality and homogeneity.

Main Results:

• Continuous monolayer, bilayer, and trilayer MoSe2 sheets with varying stacking orders were successfully grown.
• Distinctive spectroscopic features were observed for different layer numbers and stacking configurations.
• The most stable stacking orders for bilayer MoSe2 were identified as AA' and AB.
• Spectroscopy maps confirmed the high quality and uniformity of the synthesized MoSe2 sheets.

Conclusions:

• Salt-assisted CVD is an effective method for producing high-quality, layer-controlled MoSe2.
• Spectroscopic techniques provide valuable insights into the stacking order and optoelectronic properties of 2D materials.
• The findings contribute to the understanding and application of TMDs in optoelectronics.