Au-Si plasmonic platforms: synthesis, structure and FDTD simulations

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Plasmonic platforms are crucial for various optical applications.
• Gold (Au) nanostructures offer unique plasmonic properties.
• Controlling nanostructure morphology is key to enhancing performance.

Purpose of the Study:

• To synthesize homogeneous Au nanostructure plasmonic platforms.
• To investigate the effect of annealing conditions and Au film thickness on nanostructure formation.
• To validate experimental findings with theoretical simulations.

Main Methods:

• Directional solidification of Au-substrate eutectic.
• Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) for surface morphology.
• X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) for structural analysis.
• Finite-Difference Time-Domain (FDTD) simulations for electromagnetic field propagation.

Main Results:

• Au nanostructures were successfully synthesized, growing along the [111] crystallographic direction.
• Optimal homogeneity was achieved with a 2.8 nm Au film annealed at 550 °C for 15 minutes.
• FDTD simulations showed good agreement with experimental UV-vis absorbance data.

Conclusions:

• Directional solidification is an effective method for creating Au nanostructure plasmonic platforms.
• Annealing conditions and initial film thickness significantly influence nanostructure homogeneity.
• The study provides a pathway for fabricating well-defined plasmonic nanostructures for optical applications.