Charge transfer tunneling contacts for n-type monolayer semiconductor toward high performance electronics

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) semiconductors, like transition metal dichalcogenides (TMDs), offer revolutionary potential for electronics.
• Contact engineering challenges, including Fermi-level pinning and metal-induced gap states (MIGS), impede high-performance 2D material devices.

Purpose of the Study:

• To propose a novel strategy for establishing quasi-one-dimensional tunneling contacts in 2D materials.
• To overcome limitations in traditional contact engineering for 2D semiconductor devices.

Main Methods:

• Utilizing high-electron-affinity transition metal oxides (TMOs) to locally modulate the electronic properties of monolayer MoS₂.
• Introducing MoO₃ to induce charge-transfer anti-doping, creating an insulating tunneling layer.
• Fabricating field-effect transistors with Au/MoO₃-contacted monolayer-MoS₂.

Main Results:

• Achieved near-ideal ohmic characteristics with an exceptionally low Schottky barrier height (SBH) of 1.6 meV.
• Demonstrated a field-effect mobility of 559.5 cm²/V·s at 10 K.
• Showcased tunability of SBH by substituting MoO₃ with V₂O₅, confirming the strategy's versatility.

Conclusions:

• The proposed tunneling contact strategy effectively overcomes SBH limitations in 2D electronics.
• This approach offers a promising pathway for advancing next-generation high-performance 2D electronic devices.
• The method's versatility allows for tuning contact properties for diverse applications.