Doping-free complementary WSe₂ circuit via van der Waals metal integration

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) semiconductors are crucial for advanced ultra-thin body transistors.
• Controlling transistor polarity and achieving complementary logic in 2D materials are significant challenges.

Purpose of the Study:

• To present a doping-free strategy for modulating the polarity of WSe2 transistors.
• To demonstrate the fabrication of logic circuits using this polarity control method.

Main Methods:

• Utilized low-energy van der Waals integration of gold (Au) electrodes for WSe2 transistors.
• Compared van der Waals integrated contacts with conventionally deposited Au contacts on the same WSe2 flake.
• Fabricated doping-free logic inverters, NAND, and NOR gates.

Main Results:

• Achieved robust p-type transistor behavior with van der Waals integrated Au contacts.
• Observed pronounced n-type characteristics with conventional deposited Au contacts on identical WSe2 flakes.
• Demonstrated a doping-free logic inverter with a high voltage gain of 340 at 5.5 V.
• Successfully extended the strategy for complex logic functions (NAND, NOR).

Conclusions:

• The van der Waals integration method offers a simple yet effective way to control WSe2 transistor polarity without doping.
• This approach facilitates the development of high-performance, doping-free 2D logic circuits.
• The strategy is versatile for realizing complex integrated logic functions in 2D electronics.