Seeding and controlling colloidal self-assembly through focused ion beam deposition.

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Colloidal self-assembly often requires seeding for high-yield structure formation.
• Prior seeding studies primarily focused on quasi-planar substrates, limiting applications on curved surfaces.
• Controlling crystal nucleus orientation is critical for defect-free 2D crystal growth on curved substrates.

Purpose of the Study:

• To develop a novel method for seeding colloidal self-assembly on both flat and curved surfaces.
• To investigate the influence of seeding nanostructures on nucleation and growth dynamics.
• To demonstrate the control of crystal orientation on a curved surface using the developed seeding method.

Main Methods:

• Focused ion beam (FIB) deposition to create triangular well nanostructures for seeding.
• Confocal microscopy to observe depletion-mediated colloidal self-assembly dynamics.
• Application of the seeding method to both flat surfaces and a 5 μm glass fiber.

Main Results:

• Nucleation control (direct or indirect) by FIB-deposited seeds, dependent on supersaturation and interaction strength.
• Observation of both particle attachment and oriented attachment growth mechanisms.
• Successful demonstration of controlled crystal orientation on a highly curved glass fiber.

Conclusions:

• FIB deposition offers precise spatial control for seeding colloidal crystals on diverse surfaces.
• The developed method enables control over crystal orientation, essential for defect-free assembly on curved substrates.
• This approach has potential applications in geometrically frustrated systems and functional device modification.