Graphene p-n vertical tunneling diodes.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Graphene p-n junctions are crucial building blocks for electronic and photonic systems.
• Previous studies primarily focused on lateral graphene p-n junctions, which often lack rectification.
• The development of functional graphene p-n junctions with rectifying properties is highly desirable.

Purpose of the Study:

• To fabricate and characterize a new type of vertical graphene p-n junction.
• To investigate the electrical properties and rectification behavior of these vertical junctions.
• To explore potential applications in electronic and photonic devices.

Main Methods:

• Fabrication of two-terminal vertical graphene p-n junctions.
• Characterization of junction properties using electrical measurements.
• Analysis of doping concentration effects on junction behavior.

Main Results:

• Vertical graphene p-n junctions demonstrated asymmetric rectifying behavior with an on/off ratio of approximately 10^3 below ±10 V at higher n doping concentrations.
• At lower n doping concentrations, the junctions exhibited ohmic behavior, consistent with the Klein tunneling effect.
• The observed rectification is attributed to the formation of corrugated insulating or semiconducting interlayers, creating a metal-insulator-metal or metal-semiconductor-metal tunneling diode structure.
• The diode properties remained stable for at least 6 months post-fabrication.

Conclusions:

• Vertical graphene p-n junctions can be fabricated with significant rectifying properties.
• The observed rectification mechanism suggests a tunneling diode behavior, distinct from typical lateral junctions.
• These findings offer a promising pathway for developing advanced graphene-based electronic and photonic devices.