Tunable Nanoplasmonic Photodetectors.

Area of Science:

• Optoelectronics
• Plasmonics
• Nanotechnology

Background:

• Broadband photodetection typically relies on the internal photoeffect.
• Plasmonic nanostructures (nanoantennas) offer wavelength selectivity and advanced functionalities like polarization detection.
• Previous plasmonic photodetectors required large arrays for detectable photocurrents.

Purpose of the Study:

• To demonstrate a single nanoantenna capable of broadband photodetection.
• To achieve ultrasmall photodetector dimensions.
• To integrate electrical switching of color sensitivity and polarization detection into a single nanoantenna device.

Main Methods:

• Fabrication of a single electrically connected plasmonic nanoantenna.
• Coating the nanoantenna with a wide-bandgap semiconductor.
• Utilizing hot carrier injection for photodetection in the visible/near-infrared spectrum.
• Characterizing the device for broadband response, electrical switching, and polarization sensitivity.

Main Results:

• Demonstrated broadband photodetection in the visible/near-infrared range using a single nanoantenna.
• Achieved detector dimensions significantly smaller than the resonance wavelength.
• Successfully implemented electrical switching of color sensitivity.
• Showcased polarization detection capabilities at the single antenna level.

Conclusions:

• A single plasmonic nanoantenna can serve as an ultrasmall photodetector with broadband response.
• The developed device offers tunable color sensitivity and polarization detection.
• This work paves the way for highly miniaturized optical detectors with advanced functionalities.