TY - JOUR
T1 - Advanced electron crystallography through model-based imaging
AU - Van Aert, Sandra
AU - De Backer, Annick
AU - Martinez, Gerardo T.
AU - Den Dekker, Arnold J.
AU - Van Dyck, Dirk
AU - Bals, Sara
AU - Van Tendeloo, Gustaaf
PY - 2016
Y1 - 2016
N2 - The increasing need for precise determination of the atomic arrangement of non-periodic structures in materials design and the control of nanostructures explains the growing interest in quantitative transmission electron microscopy. The aim is to extract precise and accurate numbers for unknown structure parameters including atomic positions, chemical concentrations and atomic numbers. For this purpose, statistical parameter estimation theory has been shown to provide reliable results. In this theory, observations are considered purely as data planes, from which structure parameters have to be determined using a parametric model describing the images. As such, the positions of atom columns can be measured with a precision of the order of a few picometres, even though the resolution of the electron microscope is still one or two orders of magnitude larger. Moreover, small differences in average atomic number, which cannot be distinguished visually, can be quantified using high-angle annular dark-field scanning transmission electron microscopy images. In addition, this theory allows one to measure compositional changes at interfaces, to count atoms with single-atom sensitivity, and to reconstruct atomic structures in three dimensions. This feature article brings the reader up to date, summarizing the underlying theory and highlighting some of the recent applications of quantitative model-based transmisson electron microscopy.
AB - The increasing need for precise determination of the atomic arrangement of non-periodic structures in materials design and the control of nanostructures explains the growing interest in quantitative transmission electron microscopy. The aim is to extract precise and accurate numbers for unknown structure parameters including atomic positions, chemical concentrations and atomic numbers. For this purpose, statistical parameter estimation theory has been shown to provide reliable results. In this theory, observations are considered purely as data planes, from which structure parameters have to be determined using a parametric model describing the images. As such, the positions of atom columns can be measured with a precision of the order of a few picometres, even though the resolution of the electron microscope is still one or two orders of magnitude larger. Moreover, small differences in average atomic number, which cannot be distinguished visually, can be quantified using high-angle annular dark-field scanning transmission electron microscopy images. In addition, this theory allows one to measure compositional changes at interfaces, to count atoms with single-atom sensitivity, and to reconstruct atomic structures in three dimensions. This feature article brings the reader up to date, summarizing the underlying theory and highlighting some of the recent applications of quantitative model-based transmisson electron microscopy.
KW - experimental design
KW - quantitative analysis
KW - statistical parameter estimation
KW - structure refinement
KW - transmission electron microscopy
UR - http://resolver.tudelft.nl/uuid:6016a04b-3a45-440b-a456-c43513d659e3
UR - http://www.scopus.com/inward/record.url?scp=84953886973&partnerID=8YFLogxK
U2 - 10.1107/S2052252515019727
DO - 10.1107/S2052252515019727
M3 - Article
AN - SCOPUS:84953886973
SN - 2052-2525
VL - 3
SP - 71
EP - 83
JO - IUCrJ
JF - IUCrJ
IS - 1
ER -