Non-epitaxial single-crystal 2D material growth by geometric confinement

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) materials and heterostructures are crucial for advanced electronics.
• Commercialization of 2D electronics is hindered by challenges in controlled growth, single-domain formation, and wafer-scale production.

Purpose of the Study:

• To introduce a deterministic, confined-growth technique for simultaneous control over 2D material growth kinetics, domain integrity, and wafer-scale uniformity.
• To enable the production of wafer-scale single-domain 2D monolayer arrays and heterostructures on diverse substrates.

Main Methods:

• A geometrically confined growth approach using patterned silicon dioxide (SiO2) masks on two-inch substrates.
• Selective growth area definition to control nucleation and growth duration at the microscale.
• Sequential growth of transition metal dichalcogenides (TMDs) to form heterostructures without epitaxial seeding.

Main Results:

• Achieved wafer-scale single-domain monolayer tungsten diselenide (WSe2) arrays on arbitrary substrates.
• Demonstrated the formation of single-domain molybdenum disulfide (MoS2)/WSe2 heterostructures using the same confined-growth principle.
• Successfully addressed challenges in kinetic control, single-domain maintenance, and layer number/crystallinity control.

Conclusions:

• The developed confined-growth technique offers a robust solution for producing large-scale, high-quality 2D materials and heterostructures.
• This method provides a strong foundation for integrating 2D materials into industrial manufacturing processes.
• The technique overcomes critical barriers to the commercialization of 2D-based electronic devices.