Wafer-scale single-crystal hexagonal boron nitride monolayers on Cu (111)

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Two-dimensional (2D) layered materials are crucial for advancing semiconductor technology beyond Moore's Law.
• Hexagonal boron nitride (hBN) serves as an excellent interface dielectric, mitigating charge scattering in 2D semiconductors.
• Existing methods for growing single-crystal hBN face industrial scalability and fabrication compatibility challenges.

Purpose of the Study:

• To develop a reliable wafer-scale method for growing single-crystal hexagonal boron nitride (hBN) films.
• To overcome the theoretical and practical barriers to achieving mono-oriented hBN growth on copper (111) surfaces.
• To demonstrate the integration of wafer-scale hBN in advanced 2D electronic devices.

Main Methods:

• Epitaxial growth of single-crystal hBN monolayers on a copper (111) thin film deposited on a sapphire wafer.
• Utilized first-principles calculations to understand the growth mechanism and surface interactions.
• Fabricated bottom-gate transistors using the grown hBN as an interface layer between MoS2 and HfO2.

Main Results:

• Successfully achieved epitaxial growth of single-crystal hBN monolayers on a Cu (111) thin film across a two-inch wafer.
• First-principles calculations confirmed that lateral docking of hBN to Cu (111) steps enhances mono-orientation.
• Transistors incorporating the single-crystal hBN interface layer exhibited enhanced electrical performance.

Conclusions:

• A novel, reliable method for wafer-scale production of single-crystal hBN has been established.
• This advancement addresses critical challenges in 2D material integration for microelectronics.
• The developed approach paves the way for the widespread industrial adoption of 2D layered materials in electronics.