Transparent Patternable Large-Area Graphene p-n Junctions by Photoinduced Electron Doping.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Graphene's unique electronic properties make it a promising material for next-generation electronics.
• Achieving controlled doping and creating functional p-n junctions in graphene remains a significant challenge.
• Existing doping methods often lack spatial and temporal precision.

Purpose of the Study:

• To introduce a novel photoinduced electron doping method for graphene using photobase generators (PBGs).
• To demonstrate the creation of graphene p-n junctions with controlled doping.
• To explore the potential of this method for electronic, optoelectronic, and thermoelectric applications.

Main Methods:

• Utilized photobase generators (PBGs) for light-activated, spatially selective doping of graphene.
• Employed selective light irradiation to switch graphene doping from p-type to n-type.
• Characterized doping changes via electromotive force, Seebeck, and Hall coefficient measurements.
• Fabricated transparent graphene thermocouples for temperature sensing.

Main Results:

• Achieved stable n-type doping in graphene with high electron mobility (>1000 cm² V⁻¹s⁻¹) over two months.
• Successfully created graphene p-n junctions with precise doping control.
• Demonstrated transparent graphene thermocouples with a significant electromotive force (approx. 80 μV/K).

Conclusions:

• The photoinduced electron doping method offers precise spatial and temporal control over graphene doping.
• This technique enables the fabrication of high-performance graphene-based electronic and thermoelectric devices.
• The developed method is promising for practical implementation of graphene in various technological fields.