Tunable 1D van der Waals Nanostructures by Vapor-Liquid-Solid Growth

Area of Science:

• Materials Science
• Nanotechnology
• Condensed Matter Physics

Background:

• Traditional vapor-liquid-solid (VLS) growth synthesizes 3D semiconductor nanowires.
• Two-dimensional (2D) layered semiconductors offer unique anisotropic properties when structured as 1D nanostructures.
• Hexagonal 2D crystals typically form nanotubes, unlike layered monochalcogenides.

Purpose of the Study:

• To discuss achievable morphologies in 1D van der Waals (vdW) nanostructures synthesized from layered monochalcogenides.
• To explore the mechanisms governing structural features and emerging functional properties of these vdW architectures.
• To highlight the distinct nature of these nanostructures compared to traditional 3D VLS nanowires.

Main Methods:

• Vapor-liquid-solid (VLS) growth using molten metal catalysts.
• Modification of VLS catalyst via chalcogen choice or precursor additives.
• Correlated electron microscopy (imaging, nanobeam diffraction, spectroscopy) for characterization.

Main Results:

• VLS growth of layered monochalcogenides produces diverse nanowire and nanoribbon morphologies with bulk-like layered structures.
• Catalyst modification influences nanostructure morphology and vdW layering.
• Defect morphologies, including vdW bicrystals and chiral nanowires, exhibit unique properties like Eshelby twist and tunable interlayer twist.
• 1D vdW nanostructures display distinct functionalities arising from layered structure and defects, such as twist-moiré electronic modulations, chiral photonic modes, and ferroelectricity.

Conclusions:

• 1D van der Waals nanostructures represent a distinct class of materials with unique morphologies and properties.
• Defects play a crucial role, enabling novel functionalities and offering opportunities for materials design.
• These nanostructures have the potential to shift the paradigm in electronic materials science by utilizing designed defects.