Tuning interlayer coupling in large-area heterostructures with CVD-grown MoS2 and WS2 monolayers

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Monolayer transition metal dichalcogenides (TMDs) offer unique electronic properties due to band offsets.
• Developing large-area TMD heterostructures is challenging due to synthesis and interlayer coupling issues.
• These heterostructures are key for atomically thin devices and exploring 2D physics.

Purpose of the Study:

• To demonstrate large-area heterostructures of chemical vapor deposition (CVD)-grown WS2 and MoS2 monolayers.
• To externally tune and investigate the interlayer interaction from noncoupling to strong coupling.
• To study the evolution of luminescence spectra as a function of interlayer coupling.

Main Methods:

• Synthesis of large-area (>tens of micrometers) WS2 and MoS2 monolayer heterostructures using CVD.
• External tuning of interlayer coupling strength.
• Characterization of heterostructure properties via luminescence spectroscopy.

Main Results:

• Successfully fabricated large-area WS2/MoS2 monolayer heterostructures.
• Demonstrated external control over interlayer coupling, ranging from noncoupling to strong coupling.
• Observed a transition in luminescence spectra from independent layer contributions to a coupled profile driven by charge transfer and band alignment.

Conclusions:

• The study successfully demonstrates tunable interlayer coupling in large-area TMD heterostructures.
• The observed spectral evolution confirms charge transfer and band normalization effects.
• These findings pave the way for new material systems with advanced functionalities and novel physical phenomena in 2D electronics.