Aluminum plasmonics: optimization of plasmonic properties using liquid-prism-coupled ellipsometry.

Area of Science:

• Materials Science
• Optics
• Condensed Matter Physics

Background:

• Aluminum's plasmonic potential is hindered by fabrication challenges.
• Optimizing aluminum thin films is crucial for advanced optical applications.

Purpose of the Study:

• To establish a method for quantifying and optimizing aluminum thin film plasmonic behavior.
• To compare the plasmonic performance of aluminum fabricated via different methods.

Main Methods:

• Coupling spectroscopic ellipsometry with surface plasmon polaritons in a modified Otto configuration.
• Utilizing a liquid prism cell for precise optical measurements.
• Applying Ashcroft and Sturm theory to analyze optical conductivity.

Main Results:

• Sputter-deposited aluminum films at 350°C with chemical mechanical polishing exhibited the best plasmonic performance.
• Optimized aluminum demonstrated a higher figure of merit than gold, silver, and copper at blue and ultraviolet wavelengths.
• Extracted electron scattering times, interband transition energies, and optical mass from optical conductivity.

Conclusions:

• Fabrication methods significantly impact aluminum's plasmonic properties.
• Optimized aluminum is a highly competitive plasmonic material, especially for blue and UV applications.
• The study provides a comprehensive understanding of aluminum's plasmonic behavior and its underlying electronic properties.