Surface-Enhanced Infrared Absorption: Pushing the Frontier for On-Chip Gas Sensing

Area of Science:

• Plasmonics
• Nanophotonics
• Chemical Sensing

Background:

• Surface-enhanced infrared absorption (SEIRA) offers molecular fingerprinting via plasmonic coupling.
• On-chip SEIRA gas sensing faces challenges due to weak light-matter interaction and limited gas accumulation.
• Conventional SEIRA relies on localized plasmonic 'hot-spots', limiting sensitivity.

Purpose of the Study:

• To develop an enhanced SEIRA platform for sensitive on-chip gas sensing.
• To overcome limitations of traditional SEIRA by engineering broader optical field enhancement.
• To demonstrate effective carbon dioxide (CO2) detection using integrated plasmonic antennas and metal-organic frameworks (MOFs).

Main Methods:

• Fabrication of a suspended silicon nitride (Si3N4) nanomembrane device.
• Integration of plasmonic nanopatch gold antennas with a metal-organic framework (MOF) layer.
• Engineering coupled surface plasmon polaritons at metal-Si3N4 and metal-MOF interfaces for uniform field enhancement.

Main Results:

• Achieved over 1800× enhancement factors for on-chip carbon dioxide (CO2) sensing.
• Demonstrated strong optical field enhancement across the entire MOF film, not just localized hot-spots.
• Leveraged MOF nanoporous structure for significant CO2 adsorption and concentration.

Conclusions:

• The developed SEIRA device enables highly sensitive on-chip gas sensing.
• Engineered plasmonic field enhancement across a MOF film overcomes limitations of traditional SEIRA.
• This approach shows great promise for advanced gas detection technologies.