Enhancing the graphene photocurrent using surface plasmons and a p-n junction

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Graphene photodetectors offer compactness, ultrabroadband detection, and ultrafast response.
• Low optical absorption and responsivity limit practical graphene photodetector development.
• Enhancing light-graphene interaction via plasmonics is a key strategy.

Purpose of the Study:

• To develop a graphene photodetector with enhanced responsivity.
• To simultaneously improve optical absorption and electrical properties.
• To leverage both plasmonic enhancement and electrical junction control.

Main Methods:

• Designed a device architecture integrating a gap plasmon structure with split gates.
• Utilized the gap plasmon structure for light absorption and localized heating.
• Employed split gates to create a graphene p-n junction for enhanced photocarrier generation.

Main Results:

• Demonstrated simultaneous optical and electrical enhancements in the proposed device.
• Experimentally confirmed the dominance of the photothermoelectric (PTE) effect.
• Achieved a 25-fold increase in photocurrent compared to un-enhanced devices.

Conclusions:

• The proposed device architecture significantly enhances graphene photodetector performance.
• The combined plasmonic and electrical junction approach is effective for boosting responsivity.
• The device shows potential for practical applications in optoelectronics.