TY - JOUR

T1 - Atom-counting in High Resolution Electron Microscopy

T2 - TEM or STEM – That's the question

AU - Gonnissen, J.

AU - De Backer, A.

AU - den Dekker, A. J.

AU - Sijbers, J.

AU - Van Aert, S.

N1 - Accepted Author Manuscript

PY - 2017

Y1 - 2017

N2 - In this work, a recently developed quantitative approach based on the principles of detection theory is used in order to determine the possibilities and limitations of High Resolution Scanning Transmission Electron Microscopy (HR STEM) and HR TEM for atom-counting. So far, HR STEM has been shown to be an appropriate imaging mode to count the number of atoms in a projected atomic column. Recently, it has been demonstrated that HR TEM, when using negative spherical aberration imaging, is suitable for atom-counting as well. The capabilities of both imaging techniques are investigated and compared using the probability of error as a criterion. It is shown that for the same incoming electron dose, HR STEM outperforms HR TEM under common practice standards, i.e. when the decision is based on the probability function of the peak intensities in HR TEM and of the scattering cross-sections in HR STEM. If the atom-counting decision is based on the joint probability function of the image pixel values, the dependence of all image pixel intensities as a function of thickness should be known accurately. Under this assumption, the probability of error may decrease significantly for atom-counting in HR TEM and may, in theory, become lower as compared to HR STEM under the predicted optimal experimental settings. However, the commonly used standard for atom-counting in HR STEM leads to a high performance and has been shown to work in practice.

AB - In this work, a recently developed quantitative approach based on the principles of detection theory is used in order to determine the possibilities and limitations of High Resolution Scanning Transmission Electron Microscopy (HR STEM) and HR TEM for atom-counting. So far, HR STEM has been shown to be an appropriate imaging mode to count the number of atoms in a projected atomic column. Recently, it has been demonstrated that HR TEM, when using negative spherical aberration imaging, is suitable for atom-counting as well. The capabilities of both imaging techniques are investigated and compared using the probability of error as a criterion. It is shown that for the same incoming electron dose, HR STEM outperforms HR TEM under common practice standards, i.e. when the decision is based on the probability function of the peak intensities in HR TEM and of the scattering cross-sections in HR STEM. If the atom-counting decision is based on the joint probability function of the image pixel values, the dependence of all image pixel intensities as a function of thickness should be known accurately. Under this assumption, the probability of error may decrease significantly for atom-counting in HR TEM and may, in theory, become lower as compared to HR STEM under the predicted optimal experimental settings. However, the commonly used standard for atom-counting in HR STEM leads to a high performance and has been shown to work in practice.

KW - Data processing/image processing

KW - Electron microscope design and characterisation

KW - High-resolution (scanning) transmission electron microscopy (HR (S)TEM)

UR - http://resolver.tudelft.nl/uuid:8bb206bb-9b79-43b7-9465-e54921986c51

U2 - 10.1016/j.ultramic.2016.10.011

DO - 10.1016/j.ultramic.2016.10.011

M3 - Article

AN - SCOPUS:85014562351

VL - 174

SP - 112

EP - 120

JO - Ultramicroscopy

JF - Ultramicroscopy

SN - 0304-3991

ER -