Reduced Graphene Oxide/Amorphous Carbon P-N Junctions: Nanosecond Laser Patterning.

Area of Science:

• Materials Science
• Nanotechnology
• Condensed Matter Physics

Background:

• Scalable, high-quality reduced graphene oxide (rGO) production is challenging due to high-temperature requirements (>2000 K).
• Existing methods for rGO fabrication often introduce traps and defects, limiting device performance.

Purpose of the Study:

• To develop a novel, scalable method for direct laser writing of reduced graphene oxide (rGO) films.
• To investigate the properties and potential device applications of laser-processed rGO on silicon substrates.

Main Methods:

• Direct laser writing using nanosecond laser melting of amorphous carbon on silicon (001) substrates.
• Ultrafast quenching from the undercooled melt state to form large-area rGO films.
• Characterization using temperature-dependent electrical measurements and Raman spectroscopy.

Main Results:

• Formation of large-area reduced graphene oxide (rGO) films via ultrafast quenching.
• Achieved electron mobility of 12.56 cm²/V s and charge carrier concentration of -1.2 × 10²¹ /cm³.
• Fabrication of n-type rGO/p-type amorphous carbon p-n junction diodes with a turn-on voltage of 0.3 V and rectification ratio of 110@±1.5 V.

Conclusions:

• Direct laser writing offers a scalable, low-temperature alternative for high-quality rGO production.
• The method minimizes defects, enabling high conductivity and mobility in rGO films.
• Laser-processed rGO/amorphous carbon interfaces facilitate efficient p-n junction diode fabrication.