Growth of Monolayer WS₂ Lateral Homojunctions via In Situ Domain Engineering

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanoscience

Background:

• Two-dimensional (2D) lateral homojunctions offer unique properties for next-generation electronics beyond silicon.
• Challenges exist in growing these homojunctions due to limited elemental choices and maintaining crystal integrity.

Purpose of the Study:

• To report the epitaxy growth of semiconducting monolayer WS2 lateral homojunctions.
• To demonstrate the integration of D-/E-mode field-effect transistors within a single channel.
• To explore the potential of these homojunctions in constructing advanced logic devices.

Main Methods:

• Utilized in situ domain engineering during chemical vapor deposition (CVD) for WS2 growth.
• Employed domain-selective defects to modulate electronic structures.
• Performed comprehensive characterizations to analyze interface properties and device performance.

Main Results:

• Achieved optimized band alignment and ideal lattice match at the homojunction interface, resulting in strong diode-like characteristics.
• Successfully constructed homo-NMOS logic devices using the monolayer homojunctions.
• Demonstrated a sub-1 nm-thick inverter with rail-to-rail operation, a voltage gain of 12, and low power consumption (1.3 nW).

Conclusions:

• The developed approach enables in situ engineering of defect configurations and distributions in atomic layers.
• This work provides a new pathway for understanding and utilizing 2D lateral homojunctions.
• The findings accelerate the potential applications of 2D materials in nanoelectronics.