Synthesis of nanostructures in nanowires using sequential catalyst reactions

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Physics

Background:

• The vapour-liquid-solid (VLS) process is a key method for nanowire fabrication, offering control over composition, diameter, and crystal structure.
• VLS-grown nanowires have diverse applications, including solid-state lighting, single-photon sources, and thermoelectric devices.

Purpose of the Study:

• To demonstrate a novel method for tailoring nanowire morphology and composition.
• To enable the controlled incorporation of new phases within nanowires using the catalytic droplet as a 'mixing bowl'.

Main Methods:

• Sequential supply of growth materials to the liquid catalyst droplet during VLS nanowire growth.
• Nucleation and growth of new crystalline phases within the liquid droplet.
• Epitaxial incorporation of these nucleated nanocrystals into the growing nanowire.

Main Results:

• Demonstrated the ability to sequentially introduce different materials into the VLS growth process.
• Successfully incorporated metal-silicide nanocrystals into silicon (Si) nanowires.
• Achieved defect-free epitaxial interfaces between the incorporated nanocrystals and the Si nanowire.

Conclusions:

• The liquid droplet in VLS growth can serve as a 'mixing bowl' to create complex nanowire heterostructures.
• This approach offers a versatile route for designing advanced nanostructures with tailored properties.
• The method is generalizable for creating complex nanowire-based heterostructures for various applications.