1. Fast Grain Mapping with Sub-Nanometer Resolution Using 4D-STEM with Grain Classification by Principal Component Analysis and Non-Negative Matrix Factorization
- Author
-
Allen, Frances I, Pekin, Thomas C, Persaud, Arun, Rozeveld, Steven J, Meyers, Gregory F, Ciston, Jim, Ophus, Colin, and Minor, Andrew M
- Subjects
Biochemistry and Cell Biology ,Engineering ,Materials Engineering ,Biological Sciences ,Stem Cell Research ,Bioengineering ,4D-STEM ,grain orientation mapping ,NNMF ,PCA ,scanning nanobeam electron diffraction ,physics.app-ph ,cond-mat.mtrl-sci ,Condensed Matter Physics ,Microscopy ,Biochemistry and cell biology ,Materials engineering - Abstract
High-throughput grain mapping with sub-nanometer spatial resolution is demonstrated using scanning nanobeam electron diffraction (also known as 4D scanning transmission electron microscopy, or 4D-STEM) combined with high-speed direct-electron detection. An electron probe size down to 0.5 nm in diameter is used and the sample investigated is a gold–palladium nanoparticle catalyst. Computational analysis of the 4D-STEM data sets is performed using a disk registration algorithm to identify the diffraction peaks followed by feature learning to map the individual grains. Two unsupervised feature learning techniques are compared: principal component analysis (PCA) and non-negative matrix factorization (NNMF). The characteristics of the PCA versus NNMF output are compared and the potential of the 4D-STEM approach for statistical analysis of grain orientations at high spatial resolution is discussed.
- Published
- 2021