Tunable and scalable fabrication of plasmonic dimer arrays with sub-10 nm nanogaps by area-selective atomic layer deposition
Abstract
Nanogaps in metallic nanostructures produce local field enhancements with potential applications in surface enhanced spectroscopy, solar energy conversion, and photocatalysis. Atomic layer deposition is applied as a conformal coating to modify nanogap sizes and tune the optical properties of plasmonic dimer arrays with sub-10 nm nanogaps. Nanostructures are fabricated using layers of gold and palladium to combine features of plasmonics and area-selective atomic layer deposition, where copper metal is deposited on palladium-covered surfaces. Direct measurements of optical extinction for successive smaller nanogaps and thicker copper coatings show that spectral features become broadened at first due to heating-induced shape changes but subsequently sharpen as copper coatings form on palladium structures. Furthermore, longitudinal resonances of plasmonic dimers blue shift for thin coatings due to heating and decreasing aspect ratio, but thicker coatings lead to red shifts due to narrowing nanogaps. Together, these results show that area-selective atomic layer deposition is a promising tool for achieving large area arrays of plasmonic dimers with sub-10 nm nanogaps.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 30, 2021
- Source ID
- 10.1116/6.0001205
Entities
People
- Brian G. Willis
- Chengwu Zhang
- Donal Sheets
- Jason N. Hancock
- Jason Tresback
- Tuo Gao
Organizations
- Harvard University
- National Science Foundation
- Office of Naval Research
- United States Department of Energy
- University of Connecticut