High precision orientation mapping from 4D-STEM precession electron diffraction data through quantitative analysis of diffracted intensities

• Published in: Ultramicroscopy Vol. 259; p. 113927
• Main Authors: Corrêa, Leonardo M., Ortega, Eduardo, Ponce, Arturo, Cotta, Mônica A., Ugarte, Daniel
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.05.2024
• Subjects: 4D-STEM; Automated crystal orientation mapping; Eshelby twisted nanowires; High angular resolution crystal orientation measurement; Precession electron diffraction; Quantitative analysis of electron diffraction intensities; Eshelby twisted nanowires; 4D-STEM; Precession electron diffraction; Quantitative analysis of electron diffraction intensities; High angular resolution crystal orientation measurement; Automated crystal orientation mapping
• ISSN: 0304-3991; 1879-2723
• DOI: 10.1016/j.ultramic.2024.113927

•New bidimensional electron detectors allow the recording of electron diffraction data with very high speeds and high dynamical range. However, most of the diffraction analysis methods do not yet exploit diffraction intensities.•We propose a methodology to perform automated crystal orientation mapping analysis with diffraction intensities from quasi-kinematical precession electron diffraction (PED) data.•PED intensity analysis provided an angular resolution of ∼ 0.03°, much lower than common template-matching method (∼ 1°).•Intensity-based orientation analysis has been used to reveal the deformation field from a screw dislocation at the center of Eshelby twisted nanowires. The association of scanning transmission electron microscopy (STEM) and detection of a diffraction pattern at each probe position (so-called 4D-STEM) represents one of the most promising approaches to analyze structural properties of materials with nanometric resolution and low irradiation levels. This is widely used for texture analysis of materials using automated crystal orientation mapping (ACOM). Herein, we perform orientation mapping in InP nanowires exploiting precession electron diffraction (PED) patterns acquired by an axial CMOS camera. Crystal orientation is determined at each probe position by the quantitative analysis of diffracted intensities minimizing a residue comparing experiments and simulations in analogy to x-ray structural refinement. Our simulations are based on the two-beam dynamical diffraction approximation and yield a high angular precision (∼0.03°), much lower than the traditional ACOM based on pattern matching algorithms (∼1°). We anticipate that simultaneous exploration of both spot positions and high precision crystal misorientation will allow the exploration of the whole potentiality provided by PED-based 4D-STEM for the characterization of deformation fields in nanomaterials.