Epitaxial Ferroelectric Hexagonal Boron Nitride Grown on Graphene

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Ferroelectricity in van der Waals (vdW) materials is key for 2D electronic devices.
• Achieving desired non-centrosymmetric stacking for ferroelectricity during epitaxial growth is challenging.
• Heteroepitaxy on vdW substrates is difficult for creating scalable ferroelectric building blocks.

Purpose of the Study:

• To develop a method for stacking-controlled heteroepitaxy of ferroelectric vdW materials.
• To enable large-area, atomic-scale ferroelectric films for 2D devices.
• To investigate ferroelectricity in hexagonal boron nitride (h-BN) multilayer films grown on graphene.

Main Methods:

• Epitaxial growth of multilayer h-BN films on single-crystal graphene/SiC substrate.
• Theoretical calculations to understand interface polarization and stacking.
• Experimental validation using layer-dependent band dispersion measurements.

Main Results:

• Successfully grew epitaxial multilayer h-BN films on graphene.
• Demonstrated intrinsic polarization at the h-BN/graphene interface due to moiré patterns.
• Observed robust, homogeneous ferroelectricity with switchable out-of-plane polarization in h-BN films via interlayer sliding.

Conclusions:

• Established an effective route for stacking-controlled heteroepitaxy.
• Enabled large-scale integration of vdW materials with ferroelectricity.
• Provided a promising platform for next-generation 2D ferroelectric devices.