Precession Electron Diffraction Applications in TEM: from crystal structure determination to orientation imaging and strain mapping at nm scale
Vrettos STELLIOU
(Area Manager/Consultant)
Questo indirizzo email è protetto dagli spambots. È necessario abilitare JavaScript per vederlo.
Precession Electron Diffraction (PED) is a new promising technique for electron diffraction patterns collection, very close to kinematical condition, allowing in this way to solve ab-initio crystal structures of nano-crystals. On the other hand, another exciting development in Electron Crystallography is the 3-dimensional diffraction tomography technique (ADT-3D) which consists in an automatic collection of a series of randomly oriented diffraction patterns in precession mode of the same crystal through the whole TEM angular range.
Another key application including use of PED is the ASTAR technique where is possible to obtain orientation and phase maps at 1-3 nm resolution (in case of FEG-TEM) for a variety of materials (metals, alloys, semiconductors, oxides etc..). ASTAR orientation imaging can be applied for in-situ TEM strain applications where is important to analyze crystal / grain size textures at different deformation cycles.
Precession diffraction has been recently successfully applied to obtain strain mapping analysis of several semiconductor materials at 1-4 nm resolution (in case of FEG-TEM, sensitivity 0.02%), based on comparison of NBD patterns from strained /reference to un-strained areas. The technique is very easy to use at any TEM and provides very fast and accurate data without any need to index diffraction patterns.
