Ultra-precise measurement of optical aberrations for Sub-Ångström transmission electron microscopy

Quantitative investigations of material structures on an atomic scale by means of high-resolution transmission electron microscopy (HRTEM) impose not only extreme demands on the mechanic and electromagnetic stability of the applied instruments but require also their precise electron-optical adjustment. Today a physical resolution well below one Ångström can be achieved with commercially available microscopes on a daily basis. However, the achieved resolution can often not be reliably exploited for the interpretation of the resulting microscopical data due to the presence of so-called higher-order lens aberrations. At the starting time of this work, a sufficiently accurate procedure to measure higher-order aberrations was urgently missing. Since aberration measurement is a mandatory prerequisite for any technique of aberration control enabling quantitative high-resolution microscopy, the goal of this work is to develop such a measurement procedure for the Sub-Ångström regime. The measurement procedures developed in the course of this work are based on the numerical evaluation of a series of images taken from an amorphous object under electron-beam illumination with varying tilt. New techniques have been developed for the evaluation of single images as well as for the optimised evaluation of the whole series. These procedures allow microscope users to perform quantitative HRTEM even at a resolution of 0.5 Ångström. The precision reached with the newly developed measurement procedures is unprecedented and surpasses existing solutions by at least one order of magnitude in any respect. All the concepts and procedures for aberration measurement developed in this work have been implemented in a software package which satisfies professional demands with respect to robustness, precision, speed and user-friendliness. The new automatic aberration-measurement procedures are suitable to establish HRTEM as a quantitative technique for material science investigations in the Sub-Ångström regime.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2007

Author dc:creator

• Barthel, Juri

Contributors dc:contributor

• Urban, Knut

• info:eu-repo/classification/ddc/530
• Abbildungsfehler
• Durchstrahlungselektronenmikroskopie
• Hochauflösendes Verfahren
• Physik
• Aberrationsmessung
• Aberrationskontrolle
• Atomare Auflösung
• Sub-Ångström Auflösung
• aberration measurement
• transmission electron microscopy
• Sub-Ångström resolution

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

eng

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-112619%22

OAI record oai:identifier

https://publications.rwth-aachen.de/oai2d?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai%3Apublications.rwth-aachen.de%3A50055