Mode-Coupling Generation Using ITO Nanodisk Arrays with Au Substrate Enabling Narrow-Band Biosensing

Area of Science:

• Plasmonics
• Nanotechnology
• Biosensing

Background:

• Plasmonic metal nanostructures offer advanced light-matter interaction for biosensing.
• Noble metal damping leads to wide spectral widths (FWHM), limiting sensing precision.
• Novel materials are needed to overcome limitations of traditional plasmonic sensors.

Purpose of the Study:

• To develop a novel non-full-metal nanostructure sensor with improved sensing capabilities.
• To investigate the mode-coupling of surface plasmon modes in ITO-Au nanodisk arrays.
• To demonstrate the sensor's effectiveness in detecting biomolecules like immunoglobulin G (IgG).

Main Methods:

• Fabrication of periodic indium tin oxide (ITO)-Au nanodisk arrays using template transfer and vacuum deposition.
• Characterization of narrow-band spectral features resulting from mode-coupling and lattice resonance.
• Evaluation of sensing performance through the detection of IgG protein molecules.

Main Results:

• Achieved a narrow FWHM of 14 nm, a significant reduction compared to traditional full-metal nanostructures.
• Demonstrated excellent tolerance to thickness variations during nanodisk preparation.
• Successfully detected IgG protein molecules, showcasing potential for label-free biomedical applications.

Conclusions:

• The novel ITO-Au nanostructure sensor effectively reduces spectral width and enhances sensing performance.
• The proposed sensor fabrication method ensures large-area, low-cost production with high tolerance.
• This technology holds promise for advancing label-free biomedical studies and point-of-care diagnostics.