Interband plasmonic nanoresonators for enhanced thermoelectric photodetection

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Thermoelectric photodetectors offer robustness for extreme environments but suffer from low photosensitivity due to poor material absorptivity.
• Traditional thermoelectric materials like antimony telluride (Sb₂Te₃) and bismuth telluride (Bi₂Te₃) exhibit unexplored interband plasmonic resonance capabilities in the visible spectrum.

Purpose of the Study:

• To enhance the optical absorptance and photosensitivity of thermoelectric materials for photodetector applications.
• To leverage the combined plasmonic and thermoelectric properties within Sb₂Te₃ and Bi₂Te₃ nanostructures.

Main Methods:

• Fabrication of nanoresonators directly within Sb₂Te₃ and Bi₂Te₃ thermoelectric materials.
• Utilizing plasmonic field enhancements to improve optical absorptance and photo-thermoelectric conversion.
• Characterization of the solid-state device's optical absorptance, response time, and specific detectivity.

Main Results:

• Achieved approximately 90% optical absorptance across the visible spectrum, more than double that of unpatterned materials.
• Demonstrated a solid-state thermoelectric photodetector with a response time of 160 µs.
• The nanostructured thermoelectric materials exhibited significantly improved photo-thermoelectric conversion efficiency.

Conclusions:

• Integrating plasmonic nanostructures into thermoelectric materials effectively enhances optical absorptance and device performance.
• This approach validates the simultaneous exploitation of plasmonic and thermoelectric properties within a single material.
• The findings could drive advancements in photodetectors, biosensors, solar cells, and integrated spectrometers.