Sub-10 nm stable graphene quantum dots embedded in hexagonal boron nitride

Area of Science:

• Materials Science
• Quantum Physics
• Nanotechnology

Background:

• Graphene quantum dots (GQDs) are zero-dimensional nanomaterials with significant potential in quantum information and computing.
• Achieving sub-10 nm sizes is crucial for GQDs to exhibit intrinsic quantum properties.
• However, small GQDs are unstable due to edge effects and dangling bonds, posing a design challenge.

Purpose of the Study:

• To develop a method for fabricating stable sub-10 nm graphene quantum dot (GQD) arrays.
• To maintain the intrinsic quantum properties of GQDs while ensuring their stability.
• To enable advanced physical exploration and applications of GQD-based quantum materials.

Main Methods:

• Fabrication of sub-10 nm GQD arrays by embedding GQDs into hexagonal boron nitride (h-BN).
• Milling of sub-10 nm nanopore arrays in h-BN using a helium ion microscope.
• Growth of GQDs within the h-BN nanopores via chemical vapor deposition.
• Passivation of GQD dangling bonds by the surrounding h-BN lattice.

Main Results:

• Successfully fabricated stable sub-10 nm GQD arrays.
• Embedded GQDs demonstrated negligible property decay after 100 days of baking at 100 °C in air.
• The h-BN matrix effectively passivated dangling bonds, enhancing GQD stability.
• Intrinsic quantum properties of GQDs were preserved within the h-BN matrix.

Conclusions:

• Embedding GQDs in h-BN is an effective strategy to achieve stable, sub-10 nm GQD arrays.
• This approach overcomes the trade-off between quantum size and stability in GQD design.
• The developed method facilitates the exploration and application of zero-dimensional in-plane quantum materials.