A Two-Dimensional NiS/MoS₂ Metal-Semiconductor Vertical Heterojunction for a Sub-100 nm Transistor

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Reliable electrical contacts are crucial for 2D semiconducting transition-metal dichalcogenides (TMDCs) in next-generation electronics.
• Challenges include selective doping of TMDCs and physical damage during electrode integration.

Purpose of the Study:

• To develop a method for achieving reliable contacts on 2D TMDCs.
• To improve the performance of 2D electronic devices.

Main Methods:

• A two-step chemical vapor deposition strategy was employed.
• Synthesized 2D metallic NiS on monolayer MoS₂ to form vertical heterojunctions.

Main Results:

• Achieved perfect contacts and intrinsic interfaces in 2D NiS/MoS₂ heterojunctions.
• Demonstrated high average carrier mobility (59.8 cm² V^-1 s^-1) and large on/off current ratio.
• Monolayer MoS₂ transistors showed current saturation at low bias (0.9 V) with high on-state current density (1.20 mA μm^-1).

Conclusions:

• The proposed method enables high-performance van der Waals metal-semiconductor heterojunctions.
• This work advances the integration of 2D electronics, meeting targets for future devices.