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A method for structure analysis of nanomaterials by electron diffraction: phase identification and unit cell
Shi Honglong1, Zhang Guling, Zou Bin
1School of science, Minzu University of China, Beijing 100081, People's Republic of China. hlshi@muc.edu.cn
Microscopy Research and Technique
|April 5, 2013
Summary
This study presents a straightforward method for phase identification and unit cell determination using selected area electron diffraction (SAED) patterns from transmission electron microscopy (TEM). This technique simplifies crystallographic analysis of nanomaterials without specimen rotation.
Area of Science:
- Materials Science
- Crystallography
- Nanotechnology
Background:
- Accurate phase identification and unit cell determination are crucial for understanding nanomaterial properties.
- Traditional methods using selected area electron diffraction (SAED) often require complex specimen manipulation like rotation and tilting.
- Integrating transmission electron microscopy (TEM) with X-ray diffraction (XRD) software offers potential for simplified crystallographic analysis.
Purpose of the Study:
- To develop and validate a quick and easy method for crystallographic analysis of nanomaterials using SAED patterns.
- To perform phase identification and unit cell determination without rotating or tilting the specimen.
- To demonstrate the applicability of the method on various nanomaterials, including TiO2 and gold nanocrystals.
Main Methods:
- Acquiring two-dimensional (2D)-SAED patterns from a randomly selected area in a transmission electron microscope (TEM).
- Transforming the 2D-SAED pattern into a one-dimensional (1D) profile after precise center determination.
- Importing the 1D profile into X-ray diffraction (XRD) analysis software for peak searching and profile fitting.
Main Results:
- Successful phase identification and unit cell determination were achieved for flaky-like TiO2 nanomaterials and TiO2 nanotubes.
- The method was validated for crystallographic analysis of a single gold nanocrystal, confirming its utility for small diffraction volumes.
- The study indicates that multiple random tilt SAED patterns may be necessary for nanocrystals with smaller diffraction volumes.
Conclusions:
- The developed method offers a simplified approach to SAED pattern analysis for phase identification and unit cell determination.
- This technique eliminates the need for specimen rotation and tilting, streamlining the crystallographic analysis of nanomaterials.
- Future work can extend this method to quantitative phase analysis, structure determination, and Rietveld refinement by extracting reliable integrated intensities.
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