Directly Probing Interfacial Coupling in a Monolayer MoSe₂ and CuPc Heterostructure

Area of Science:

• Materials Science
• Nanotechnology
• Condensed Matter Physics

Background:

• Organic-inorganic van der Waals (vdW) heterostructures (HSs) are promising for next-generation flexible devices.
• Interfacial coupling strength significantly influences the properties of vdW HSs.
• Noninvasive methods are needed to evaluate this coupling for device optimization.

Purpose of the Study:

• To develop and demonstrate a noninvasive method for evaluating interfacial coupling strength in vdW HSs.
• To probe the coupling between monolayer Molybdenum Diselenide (MoSe₂) and copper phthalocyanine (CuPc) thin films.
• To utilize a novel Raman mode as an indicator of coupling strength modulation.

Main Methods:

• Combined electrical force microscopy (EFM) with Raman and photoluminescence spectroscopy.
• Investigated the MoSe₂/CuPc heterostructure.
• Identified a new Raman mode arising from Davydov splitting in CuPc due to strong interfacial coupling.

Main Results:

• Successfully probed the interfacial coupling strength between MoSe₂ and CuPc.
• Observed a new Raman mode indicative of strong vdW coupling.
• Demonstrated that this Raman mode can track changes in coupling strength with post-treatment conditions.

Conclusions:

• The developed method effectively and innovatively evaluates interfacial coupling strength in MoSe₂/CuPc HSs.
• The new Raman mode serves as a valuable probe for understanding interfacial interactions.
• Provides insights for optimizing hybrid vdW HSs for future optical and optoelectrical applications.