Synthesis of large-area multilayer hexagonal boron nitride for high material performance

Area of Science:

• Materials Science
• Nanotechnology
• Condensed Matter Physics

Background:

• Hexagonal boron nitride (h-BN) is a promising gate insulator for 2D electronic devices due to minimal substrate interaction.
• Current synthesis methods limit h-BN applications due to small flake sizes, particularly for multilayer structures.

Purpose of the Study:

• To synthesize large-area multilayer h-BN films using chemical vapor deposition (CVD).
• To evaluate the quality and performance of the synthesized multilayer h-BN in electronic devices.

Main Methods:

• Chemical vapor deposition (CVD) synthesis of multilayer h-BN on Fe foil using a borazine precursor.
• Characterization of h-BN film properties, including cathodoluminescence and mechanical strength (Young's modulus).
• Fabrication and electrical characterization of graphene and MoS2/WSe2 field-effect transistors using the synthesized h-BN.

Main Results:

• Successful synthesis of large-area multilayer h-BN films with high quality, indicated by strong cathodoluminescence and high mechanical strength (1.16 ± 0.1 TPa).
• CVD-grown graphene on multilayer h-BN exhibited significantly higher carrier mobility (∼24,000 cm(2) V(-1) s(-1)) compared to exfoliated h-BN (∼13,000 cm(2) V(-1) s(-1)).
• Integration of h-BN in MoS2 (WSe2) field-effect transistors minimized gate oxide doping and improved mobility by four (150) times.

Conclusions:

• Large-area multilayer h-BN films can be synthesized via CVD, overcoming previous size limitations.
• The synthesized h-BN films are suitable for high-performance 2D electronic devices, enhancing carrier mobility and reducing substrate effects.
• This work paves the way for advanced applications of h-BN in next-generation electronics.