STEMx 系统

4D STEM and virtual aperture imaging

A 4D STEM diffraction data cube collected using the Stela camera and STEMx system. Specimen: Au nanoparticles. Scan area: 176 x 218 pixels, Diffraction image size: 256 x 256 pixels. Dwell time: 5 ms. Color map showing grain orientations classified based on the angular position of the maximum diffraction peak per probe position using a DigitalMicrograph script.

4D STEM operating principle

Metro captures 4D STEM data with sharper detail and less background noise; it can collect a 128 x 128 (scan) x 512 x 512 (pattern) dataset in half a minute. This color image is a map of the brightest spot orientation and intensity from such a dataset. The material is boron nitride. The color hue in the map specifies the direction from center of the strongest spot in each diffraction pattern, while the brightness corresponds to the intensity of the peak.

The new STEMx OIM package brings orientation mapping analysis to the STEMx integrated software tools. This is done by comparing the diffraction pattern at each pixel position to a set of simulated patterns for all phases and orientations in your specimen. Orientation data can even be exported to the EDAX OIM Analysis software for further processing. Orientation map generated with STEMx OIM showing {111} texture of annealed Au thin film. Energy-filtered 4D STEM data was collected using a GIF Continuum with Stela system at 200 kV. Sample courtesy of J. Kacher, GA Tech.