Plasmon induced thermoelectric effect in graphene.

Area of Science:

• Optoelectronics
• Materials Science
• Plasmonics

Background:

• Graphene exhibits potential for ultrafast and broad-band photodetection.
• Graphene junctions show two photocurrent mechanisms: photovoltaic and photothermoelectric (PTE) effects.
• The dominant PTE effect is linked to Seebeck coefficient variations or electronic temperature gradients.

Purpose of the Study:

• To investigate the photothermoelectric effect in homogeneous graphene channels.
• To explore plasmonic heating of graphene carriers for photocurrent generation.
• To analyze the device's function as an electronic thermometer.

Main Methods:

• Utilized strongly localized plasmonic heating of graphene carriers.
• Employed nanostructured electrical contacts to create electronic temperature gradients.
• Isolated the plasmon-induced PTE photocurrent contribution under specific conditions.

Main Results:

• Achieved electronic temperatures of approximately 2000 K through plasmonic heating.
• Demonstrated the isolation of the plasmon-induced PTE photocurrent.
• Showcased the device's sensitivity as an electronic thermometer.

Conclusions:

• The study highlights a secondary photothermoelectric effect in homogeneous graphene.
• Plasmonic heating enables efficient hot carrier generation and PTE photocurrent.
• The device is a promising platform for hot carrier plasmonic devices and sensitive thermometry.