Waveguide-Integrated, Plasmonic Enhanced Graphene Photodetectors

Area of Science:

• Photonics and Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Graphene photodetectors (GPDs) are promising for optical communication due to their unique electronic properties.
• Existing GPDs often suffer from dark current and limited bandwidth, hindering their practical application.
• Enhancing light-matter interaction is crucial for improving photodetector performance.

Purpose of the Study:

• To present a micrometer-scale, on-chip integrated, plasmon-enhanced graphene photodetector (GPD).
• To achieve zero dark current operation for telecom wavelengths.
• To improve responsivity and bandwidth using plasmonic effects and a photothermoelectric mechanism.

Main Methods:

• Fabrication of a GPD using chemical vapor deposited single-layer graphene.
• Integration of gold split-gates to create an electrostatic p-n junction.
• Utilizing a surface plasmon polariton gap-mode to enhance light-graphene interaction.
• Leveraging the photothermoelectric effect for photovoltage generation.

Main Results:

• Achieved zero dark current operation at telecom wavelengths.
• External responsivity of approximately 12.2 V/W.
• 3 dB bandwidth of approximately 42 GHz.
• Enhanced optical absorption and electronic temperature due to plasmonic effects.

Conclusions:

• The developed GPD demonstrates high performance and zero dark current, suitable for telecom applications.
• Plasmonic enhancement and the photothermoelectric effect are effective strategies for high-performance GPDs.
• This technology paves the way for compact, power-efficient graphene-based photodetectors for tele- and datacom modules.