Improving data quality for 3D electron diffraction (3D ED) by Gatan Image Filter and a new crystal tracking method

TL;DR

This paper enhances 3D electron diffraction by integrating a Gatan Energy Filter and introducing a novel crystal tracking method, resulting in improved data quality and larger tilt range collection.

Contribution

It details the implementation of energy-filtered 3D ED with a Gatan GIF and proposes a live HAADF image-based crystal tracking method in STEM mode, expanding capabilities.

Findings

Energy-filtered 3D ED improves R1 by 20-30%.

Structures become more reasonable with filtering.

Method enables larger tilt range data collection.

Abstract

3D ED is an effective technique to determine the structures of submicron- or nano-sized crystals. In this paper, we implemented energy-filtered 3D ED using a Gatan Energy Filter (GIF) in both selected area electron diffraction mode and micro/nanoprobe mode. We explained the setup in detail, which improves the accessibility of energy-filtered 3D ED experiments as more electron microscopes are equipped with a GIF than an in-column filter. We also proposed a crystal tracking method in STEM mode using live HAADF image stream. This method enables us to collect energy-filtered 3D ED datasets in STEM mode with a larger tilt range without foregoing any frames. In order to compare the differences between energy-filtered 3D ED and normal 3D ED data, three crystalline samples have been studied in detail. We observed that the final R1 will improve 20% to 30% for energy-filtered datasets compared with unfiltered datasets and the structure became more reasonable. We also discussed the possible reasons that lead to the improvement.