Surface-enhanced infrared absorption with Si-doped InAsSb/GaSb nano-antennas.

Area of Science:

• Materials Science
• Spectroscopy
• Nanotechnology

Background:

• Surface-enhanced infrared absorption (SEIRA) spectroscopy is a powerful technique for molecular detection.
• Plasmonic nano-antennas offer enhanced light-matter interactions for improved SEIRA sensitivity.
• Tailoring nano-antenna properties is crucial for optimizing SEIRA performance at specific molecular vibrational frequencies.

Purpose of the Study:

• To demonstrate SEIRA spectroscopy using 1D Si-doped InAsSb plasmonic nano-antennas.
• To investigate the effect of doping level and nano-antenna width on SEIRA enhancement.
• To establish a pathway for manufacturing molecule fingerprint sensors.

Main Methods:

• Fabrication of 1D Si-doped InAsSb plasmonic nano-antennas with varying doping levels and widths.
• Characterization of nano-antenna optical properties and their alignment with molecular vibrational modes.
• Measurement of SEIRA signals from a ~15 nm thick organic layer on nano-antennas and unstructured samples.

Main Results:

• Localized surface plasmon resonance (LSPR) was engineered by tuning doping and nano-antenna width.
• Heavily doped nano-antennas required wider dimensions than lightly doped ones.
• Vibrational absorption was enhanced by up to two orders of magnitude compared to unstructured samples, improving sensing capabilities.

Conclusions:

• Si-doped InAsSb plasmonic nano-antennas enable highly sensitive SEIRA spectroscopy.
• Tailoring plasmonic resonators to specific vibrational modes maximizes SEIRA enhancement.
• This approach is promising for the development of advanced molecule fingerprint sensors.