Large-area single-layer MoSe2 and its van der Waals heterostructures

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Layered transition metal dichalcogenides exhibit unique properties at the monolayer limit.
• Current synthesis methods for monolayers have low yields and limited scalability.
• Van der Waals heterostructures offer potential for novel electronic and optoelectronic devices.

Purpose of the Study:

• To develop a scalable method for synthesizing large-area, high-quality molybdenum diselenide (MoSe2) monolayers.
• To investigate the properties of synthesized MoSe2 monolayers.
• To explore the characteristics of MoSe2/graphene heterostructures.

Main Methods:

• Synthesis of MoSe2 monolayers via selenization of MoO3 using chemical vapor deposition (CVD).
• Characterization of MoSe2 using photoluminescence spectroscopy.
• Fabrication and analysis of MoSe2/graphene van der Waals heterostructures.

Main Results:

• Achieved synthesis of large-area, uniform MoSe2 monolayers on various substrates (SiO2, sapphire).
• Confirmed intrinsic doping in MoSe2 monolayers through charged exciton formation.
• Observed strong photoluminescence quenching in MoSe2/graphene heterostructures, indicating rapid charge carrier transfer.

Conclusions:

• The CVD-based selenization method provides a scalable route to high-quality MoSe2 monolayers.
• MoSe2/graphene heterostructures demonstrate efficient charge transfer, promising for optoelectronics.
• Advancements in controlled heterostructure synthesis will drive progress in low-dimensional systems and applications.