Unveiling the complexity of nanodiamond structures
Abstract
Understanding nanodiamond structures is of great scientific and practical interest. It has been a long-standing challenge to unravel the complexity underlying nanodiamond structures and to resolve the controversies surrounding their polymorphic forms. Here, we use transmission electron microscopy with high-resolution imaging, electron diffraction, multislice simulations, and other supplementary techniques to study the impacts of small sizes and defects on cubic diamond nanostructures. The experimental results show that common cubic diamond nanoparticles display the (200) forbidden reflections in their electron diffraction patterns, which makes them indistinguishable from new diamond (n-diamond). The multislice simulations demonstrate that cubic nanodiamonds smaller than 5 nm can present the d -spacing at 1.78 Å corresponding to the (200) forbidden reflections, and the relative intensity of these reflections increases as the particle size decreases. Our simulation results also reveal that defects, such as surface distortions, internal dislocations, and grain boundaries can also make the (200) forbidden reflections visible. These findings provide valuable insights into the diamond structural complexity at nanoscale, the impact of defects on nanodiamond structures, and the discovery of novel diamond structures.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- May 30, 2023
- Source ID
- 10.1073/pnas.2301981120
Entities
People
- Hai Wang
- Haimei Zheng
- Haiyan Mao
- Jeffrey Reimer
- Jinyang Jiang
- Nicholas Montes
- Nikolaos Kateris
- Qi Zheng
- Xian Shi
Organizations
- Air Force Office of Scientific Research
- Lawrence Berkeley National Laboratory
- National Natural Science Foundation of China
- National Science Foundation
- Southeast University
- Stanford University
- United States Department of Energy