Abstract
A method to measure the thickness of a single-crystal nanoparticle in the direction parallel to the incident beam from annular dark field scanning transmission electron microscope (ADF-STEM) images is reported, providing a map of thickness versus position across the nanoparticle-a 'thickness profile' image. The method is rapid and hence suitable for surveying large numbers of nanoparticles. The method measures the intensity scattered to a characterised ADF detector and compares this to the incident beam intensity, to obtain a normalized ADF image. The normalised intensity is then converted to thickness via dynamical ADF image simulations. The method is accurate within 10% and the precision is dominated primarily by 'shot noise'. Merits and limitations of this method are discussed. A method to calibrate the response function of the ADF detector without external equipment is also described, which is applicable to the entire range of gain and background settings.
Original language | English (US) |
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Pages (from-to) | 61-70 |
Number of pages | 10 |
Journal | Ultramicroscopy |
Volume | 124 |
DOIs | |
State | Published - Jan 1 2013 |
Externally published | Yes |
Keywords
- Annular dark field (ADF) detector Characterisation
- Gold nanorods
- Nanoparticles
- Quantitative ADF-STEM
- Thickness profile determination
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Instrumentation