Gate-Tunable Graphene-WSe₂ Heterojunctions at the Schottky-Mott Limit

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Schottky junctions are crucial for electronic devices but are often limited by defects and impurities.
• These imperfections cause Fermi level pinning, hindering control over the junction's electrical properties.

Purpose of the Study:

• To investigate a graphene-WSe2 p-type Schottky junction that overcomes Fermi level pinning.
• To explore the tunable Schottky barrier height and its implications for device characteristics.

Main Methods:

• Fabrication of a graphene-WSe2 heterostructure to form a p-type Schottky junction.
• Utilizing electrostatic gating to modulate the WSe2 channel and tune the Schottky barrier height.
• Characterization of diode characteristics, including gate tunability and leakage currents.

Main Results:

• The graphene-WSe2 Schottky junction demonstrated a lack of Fermi level pinning.
• Near-ideal diode characteristics with significant gate tunability and low leakage currents were observed.
• The study successfully probed the Schottky-Mott limit in a single device.
• A diode with a dynamically controlled ideality factor was realized.

Conclusions:

• Graphene-WSe2 heterostructures offer a promising platform for high-performance Schottky junctions free from Fermi level pinning.
• The ability to tune the Schottky barrier height opens new avenues for advanced electronic device design.
• This work paves the way for diodes with dynamically controllable electrical properties.