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Updated: May 20, 2026
13:56
Probe Type II Band Alignment in One-Dimensional Van Der Waals Heterostructures Using First-Principles Calculations
Published on: October 12, 2019
Dislocations and grain boundaries in two-dimensional boron nitride.
Yuanyue Liu1, Xiaolong Zou, Boris I Yakobson
1Department of Mechanical Engineering and Materials Science, and the Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, USA.
ACS Nano
|July 12, 2012
Summary
A novel square-octagon dislocation in two-dimensional boron nitride (h-BN) was discovered. This structure offers lower energy and unique grain boundary properties, suggesting potential electronic and optical applications.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Computational Materials Science
Background:
- Two-dimensional materials like hexagonal boron nitride (h-BN) exhibit unique properties due to their atomic structure.
- Dislocations and grain boundaries significantly influence the electronic and mechanical properties of materials.
- Understanding these defects is crucial for optimizing material performance and exploring new applications.
Purpose of the Study:
- To discover and characterize novel dislocation structures in two-dimensional boron nitride (h-BN).
- To investigate the formation and properties of grain boundaries (GBs) in h-BN based on dislocation structures.
- To explore the potential electronic and optical applications of these grain boundaries.
Main Methods:
- First-principles calculations were employed to identify and analyze dislocation structures.
- The energy of different dislocation configurations, specifically square-octagon (4|8) and pentagon-heptagon (5|7) pairs, was compared.
- The atomic structure and electronic properties of various grain boundaries in h-BN were systematically investigated.
Main Results:
- A new dislocation structure, the square-octagon pair (4|8), was discovered in h-BN.
- The 4|8 dislocation structure exhibits lower energy compared to the 5|7 pairs due to the absence of unfavorable homoelemental bonds.
- Two types of grain boundaries were identified: polar (B-rich or N-rich, composed of 5|7s) and unpolar (composed of 4|8s).
- Polar grain boundaries possess net charges and exhibit a smaller bandgap than perfect h-BN.
Conclusions:
- The discovery of the 4|8 dislocation in h-BN provides a new structural motif for understanding defects in 2D materials.
- The identified polar and unpolar grain boundaries offer distinct characteristics based on their composition and structure.
- The reduced bandgap in polar grain boundaries suggests promising avenues for novel electronic and optical device applications in h-BN.
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