Selective sputtering and atomic resolution imaging of atomically thin boron nitride membranes

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Atomically thin materials offer unique properties.
• Hexagonal boron nitride (h-BN) is a 2D material with potential applications.
• Understanding material behavior under electron beam irradiation is crucial for characterization.

Purpose of the Study:

• To investigate the preparation and atomic resolution imaging of few-layer boron nitride.
• To elucidate the element selective damage mechanisms under high-energy electron beam irradiation.
• To compare defect formation in h-BN with that in graphene.

Main Methods:

• Mechanical exfoliation of hexagonal boron nitride (h-BN) flakes.
• Thinning of h-BN flakes to single layers using a high-energy electron beam.
• Atomic resolution imaging using transmission electron microscopy (TEM).

Main Results:

• Successful preparation and imaging of atomically thin h-BN membranes.
• Observation of highly element-selective sputtering, predominantly at the exit surface.
• Formation of triangular holes aligned with crystallographic orientation and defect-driven atom removal.

Conclusions:

• Hexagonal boron nitride can exist as a stable quasi-two-dimensional allotrope.
• High-energy electron beams induce selective damage in h-BN, revealing specific sputtering mechanisms.
• h-BN is a viable substrate-free 2D material, similar to graphene.