Suspended Monolayer Boron Nitride via Reactive Ion Etching
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Solution Overview
Problem
Current methods for isolating single layer hexagonal boron nitride (h-BN) are inefficient due to strong interplane bonding, making it difficult to obtain monolayer sheets, and conventional TEMs lack the resolution to distinguish boron from nitrogen, leading to potential instrumentation errors and misidentification of atomic sublattices.
Innovation Solution
A method involving mechanical exfoliation and reactive ion etching is used to suspend multilayer boron nitride across a support structure, followed by a reactive ion etch to produce single layer h-BN, allowing for the isolation of suspended, monolayer membranes and enabling high-resolution TEM imaging to distinguish boron and nitrogen atoms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical exfoliation is used to isolate single layer h-BN, then monolayer sheets can be obtained, but the strong interplane bonding makes it difficult to isolate single layers
Solution Approach 1:
The patent divides the multilayer h-BN into individual monolayer sheets through mechanical exfoliation, separating the strongly bonded layers into discrete, isolatable units that can be transferred to substrates for further processing
Solution Approach 2:
The patent applies reactive ion etching in a controlled manner to partially remove material from exfoliated h-BN layers, using the etching process to thin multilayer regions while preserving monolayer areas for selective processing and characterization
2Measurement precision
If conventional TEM is used for imaging, then imaging can be performed, but the resolution is insufficient to distinguish boron from nitrogen atoms
Solution Approach 1:
The patent introduces a support structure with specific structural features that act as an intermediary, providing geometric references and contrast enhancement that enable conventional TEM to distinguish boron and nitrogen atoms without requiring advanced instrumentation
Solution Approach 2:
The patent optimizes TEM imaging parameters including acceleration voltage, objective aperture settings, and focus conditions to maximize the contrast between boron and nitrogen atoms, enabling atomic distinction with conventional instrumentation
3Manufacturing precision
If reactive ion etch is applied to multilayer boron nitride, then single layer h-BN can be produced, but the etching process must be precisely controlled
Solution Approach 1:
The patent employs in-situ monitoring during reactive ion etching to provide real-time feedback on layer thickness and etching rate, enabling precise control of the etching process to achieve monolayer production while minimizing damage and variability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for the production of high-quality single layer h-BN samples, enabling accurate identification of atomic structure, defects, and edges, and overcoming the limitations of conventional TEM instrumentation errors.
Implementation Method 1
performing a reactive ion etch upon the multilayer boron nitride to produce the single layer hexagonal boron nitride
Data Source
AI summary
The present invention provides a method of fabricating at least one single layer hexagonal boron nitride (h-BN). In an exemplary embodiment, the method includes (1) suspending at least one multilayer boron nitride across a gap of a support structure and (2) performing a reactive ion etch upon the multilayer boron nitride to produce the single layer hexagonal boron nitride suspended across the gap of the support structure. The present invention also provides a method of fabricating single layer hexagonal boron nitride. In an exemplary embodiment, the method includes (1) providing multilayer boron nitride suspended across a gap of a support structure and (2) performing a reactive ion etch upon the multilayer boron nitride to produce the single layer hexagonal boron nitride suspended across the gap of the support structure.