Doping-Free Complementary Logic Gates Enabled by Two-Dimensional Polarity-Controllable Transistors.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Electrical Engineering

Background:

• Atomically thin two-dimensional (2D) materials, particularly transition metal dichalcogenides, offer unique physical and electrical properties for advanced semiconductor devices.
• Tungsten diselenide (WSe2) exhibits ambipolar conduction, making it suitable for polarity-controllable transistors.

Purpose of the Study:

• To demonstrate a complete doping-free standard cell library on WSe2.
• To achieve dynamic control of transistor polarity (n- or p-type) using a polarity gate and electrostatic doping.
• To realize highly expressive logic gates with fewer transistors than conventional methods.

Main Methods:

• Experimental demonstration of a doping-free logic cell library on WSe2.
• Utilizing a polarity gate for electrostatic doping of Schottky junctions to control device polarity.
• Implementing complementary logic gates including INV, NAND, NOR, XOR, and MAJ.

Main Results:

• A functionally complete family of complementary logic gates was realized without chemical or physical doping.
• Highly expressive logic gates like exclusive-OR (XOR) and majority (MAJ) were achieved using fewer transistors than in complementary metal-oxide-semiconductor (CMOS) logic.
• Demonstrated dynamic, device-level control of transistor polarity.

Conclusions:

• This work paves the way for doping-free, low-power electronics based on 2D semiconductors.
• The approach moves beyond unipolar, physically doped devices, enabling higher computational densities in 2D electronics.