Directed crystallisation of zinc oxide on patterned surfaces

Area of Science:

• Materials Science
• Nanotechnology
• Surface Chemistry

Background:

• Self-assembled monolayers (SAMs) are crucial for creating functionalized surfaces.
• Controlling crystal nucleation and growth on patterned substrates is essential for nanomaterial fabrication.

Purpose of the Study:

• To investigate the selective nucleation and growth of zinc oxide (ZnO) crystals on chemically patterned surfaces.
• To utilize UV-photolithography and SAMs to template ZnO crystallization.

Main Methods:

• Fabrication of patterned SAMs on gold substrates using UV-photolithography with 11-mercaptoundecanoic acid (MUA) and fluorinated decane thiol (FDT).
• Exposure of patterned surfaces to a 10 mM zinc nitrate solution to induce crystallization.
• Characterization of ZnO crystal morphology and growth orientation.

Main Results:

• Selective nucleation of ZnO occurred on low surface energy regions (FDT) of the patterned SAMs.
• Uniform growth of upright hexagonal ZnO prisms (1 µm length, 50-100 nm diameter) was observed on the low energy regions.
• Growth was attributed to crystallographic frustration on high energy regions (MUA) and hydroxide ion accumulation on low energy regions.

Conclusions:

• Chemically patterned SAMs effectively template the selective growth of ZnO nanostructures.
• Surface energy and ion accumulation play key roles in directing nucleation and crystal growth.
• This method offers precise control over ZnO nanostructure fabrication for potential applications.