Near-ideal van der Waals rectifiers based on all-two-dimensional Schottky junctions.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Metal-semiconductor interfaces are critical for 2D semiconductor devices but are often limited by Fermi pinning and defect states.
• Conventional metal contacts lead to significant Fermi level pinning, hindering device performance.
• Developing effective strategies to control these interfaces is crucial for advancing 2D electronics.

Purpose of the Study:

• To engineer a near-ideal Schottky rectifier using all-2D materials.
• To investigate the role of van der Waals integration in overcoming Fermi pinning effects.
• To demonstrate a method for enhancing Schottky barrier height and width in 2D heterojunctions.

Main Methods:

• Fabrication of all-2D Schottky junctions using 1T omino-MoTe2 (2D metal) and monolayer MoS2 (semiconductor).
• Utilizing van der Waals integration to form the heterostructure.
• Employing defect healing techniques on MoS2 to reduce intrinsic defect doping and enlarge Schottky barrier width.

Main Results:

• Achieved a near-ideal rectifier with an ideality factor of ~1.6.
• Demonstrated a high rectifying ratio exceeding 5 × 10^5.
• Observed a significant 59% enlargement of the Schottky barrier width.
• Reported high external quantum efficiency over 20%.

Conclusions:

• Van der Waals integration of 1T omino-MoTe2 and MoS2 effectively mitigates Fermi pinning and enhances Schottky barrier properties.
• Defect healing in MoS2 is a viable strategy to improve device performance by increasing barrier width.
• The developed barrier optimization strategy offers a general solution for enhancing performance in various 2D-material-based Schottky junctions and electronic devices.