Epitaxial Atomic Substitution for MoS₂-MoN Heterostructure Synthesis

Area of Science:

• Materials Science
• Nanotechnology
• Condensed Matter Physics

Background:

• Integrating diverse two-dimensional (2D) crystals is crucial for next-generation electronics.
• MXenes offer high conductivity and stability for 2D electrodes, but integration with 2D semiconductors is limited by synthesis methods.
• Atomic substitution synthesis of non-van der Waals (non-vdW) transition metal nitrides (TMNs) from van der Waals (vdW) transition metal dichalcogenides (TMDs) presents new integration opportunities.

Purpose of the Study:

• To investigate the atomic substitution process converting semiconducting MoS2 to metallic MoN.
• To realize and characterize lateral and vertical MoN-MoS2 heterostructures.
• To explore the potential of these heterostructures for electronic applications.

Main Methods:

• Atomic substitution synthesis via controllable partial conversion of TMDs to TMNs.
• High-resolution transmission electron microscopy (HRTEM) for structural analysis.
• Mask-assisted synthesis for patterned heterostructures.
• Electrical measurements to determine interface properties.

Main Results:

• Successfully converted semiconducting MoS2 to metallic MoN.
• Fabricated both lateral and vertical MoN-MoS2 heterostructures with distinct interface structures (atomically bonded vs. moiré patterns).
• Demonstrated patterned lateral heterostructures using mask-assisted synthesis.
• Measured a low Schottky barrier height (meV) at the MoS2-MoN interface.

Conclusions:

• Atomic substitution synthesis enables the creation of novel MoN-MoS2 heterostructures.
• These heterostructures exhibit promising properties for advanced electronic devices.
• MoN can serve as an effective contact electrode for MoS2-based electronics.