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In-line three-dimensional holography of nanocrystalline objects at atomic resolution.

Chen FR, Van Dyck D, Kisielowski C - Nat Commun (2016)

Bottom Line: Resolution and sensitivity of the latest generation aberration-corrected transmission electron microscopes allow the vast majority of single atoms to be imaged with sub-Ångstrom resolution and their locations determined in an image plane with a precision that exceeds the 1.9-pm wavelength of 300 kV electrons.The method is compatible with low dose rate electron microscopy, which improves on signal quality, while minimizing electron beam-induced structure modifications even for small particles or surfaces.We apply it to germanium, gold and magnesium oxide particles, and achieve a depth resolution of 1-2 Å, which is smaller than inter-atomic distances.

View Article: PubMed Central - PubMed

Affiliation: Department of Engineering and System Science, National Tsing-Hua University, 101 Kuang-Fu Road, Hsin Chu 300, Taiwan.

ABSTRACT
Resolution and sensitivity of the latest generation aberration-corrected transmission electron microscopes allow the vast majority of single atoms to be imaged with sub-Ångstrom resolution and their locations determined in an image plane with a precision that exceeds the 1.9-pm wavelength of 300 kV electrons. Such unprecedented performance allows expansion of electron microscopic investigations with atomic resolution into the third dimension. Here we report a general tomographic method to recover the three-dimensional shape of a crystalline particle from high-resolution images of a single projection without the need for sample rotation. The method is compatible with low dose rate electron microscopy, which improves on signal quality, while minimizing electron beam-induced structure modifications even for small particles or surfaces. We apply it to germanium, gold and magnesium oxide particles, and achieve a depth resolution of 1-2 Å, which is smaller than inter-atomic distances.

No MeSH data available.


Related in: MedlinePlus

Atomic resolution tomograms.(a) Surface shape and atomic structure views of the Ge [110] sample. (b) Surface shape and atomic structure views of the Au[110] sample. The facets are highlighted with different colours. (c) Surface shape and atomic structure views of the MgO [100] sample. Orange atoms: Mg, blue atoms: O (the size of the atoms is intentionally enlarged to render the shape of the particle). (d) The Wulf net shows the relationship of the high-energy facets (red dots) with low indexed facets for four grains indexed with i=1… 4. In grain 1, a [02] surface facet can be formed by low energetic [010] and [00] (red symbols) surfaces as shown by the insets and observed in the tomogram.
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f4: Atomic resolution tomograms.(a) Surface shape and atomic structure views of the Ge [110] sample. (b) Surface shape and atomic structure views of the Au[110] sample. The facets are highlighted with different colours. (c) Surface shape and atomic structure views of the MgO [100] sample. Orange atoms: Mg, blue atoms: O (the size of the atoms is intentionally enlarged to render the shape of the particle). (d) The Wulf net shows the relationship of the high-energy facets (red dots) with low indexed facets for four grains indexed with i=1… 4. In grain 1, a [02] surface facet can be formed by low energetic [010] and [00] (red symbols) surfaces as shown by the insets and observed in the tomogram.

Mentions: To convert column mass values into radians, we determined experimentally the phase changes of the electron wave caused by scattering at one gold atom and one MgO molecule (Methods). Table 1 lists these phase values. It is seen that the phase of the exit wave is changed by 0.21±0.07 rad by passing through a single gold atom in an atomic column or by 0.08±0.02 rad if it is passing through a single MgO molecule. A value of 0.11 rad for scattering at one Ge atom is estimated using a Z2/3 dependence. Remarkably, it is also seen that error bars increase with increasing dose rates, suggesting that measurements with a best element differentiation can only be performed if dose rates are kept low. In addition, column locations in the beam direction can be determined to a precision 1.2–2.4 Å on an absolute scale. Consequently, depth resolution has reached interatomic distances in thickness reconstructions from single projections. It is now straightforward to create 3D tomograms from these measurements, as the focus values describe the exit surface profile of the sample and the column length is given by the number of atoms of known spacing along the column length. In this manner, we have created the tomograms (Fig. 4) that show all geometrical properties that one expects to be imprinted by the chosen sample preparation procedure. The number of atoms in each tomogram is a time average that is dose rate dependent and equals 35,389 for Ge, 4,883 for Au and 10,750 (Mg, O) for MgO.


In-line three-dimensional holography of nanocrystalline objects at atomic resolution.

Chen FR, Van Dyck D, Kisielowski C - Nat Commun (2016)

Atomic resolution tomograms.(a) Surface shape and atomic structure views of the Ge [110] sample. (b) Surface shape and atomic structure views of the Au[110] sample. The facets are highlighted with different colours. (c) Surface shape and atomic structure views of the MgO [100] sample. Orange atoms: Mg, blue atoms: O (the size of the atoms is intentionally enlarged to render the shape of the particle). (d) The Wulf net shows the relationship of the high-energy facets (red dots) with low indexed facets for four grains indexed with i=1… 4. In grain 1, a [02] surface facet can be formed by low energetic [010] and [00] (red symbols) surfaces as shown by the insets and observed in the tomogram.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4759637&req=5

f4: Atomic resolution tomograms.(a) Surface shape and atomic structure views of the Ge [110] sample. (b) Surface shape and atomic structure views of the Au[110] sample. The facets are highlighted with different colours. (c) Surface shape and atomic structure views of the MgO [100] sample. Orange atoms: Mg, blue atoms: O (the size of the atoms is intentionally enlarged to render the shape of the particle). (d) The Wulf net shows the relationship of the high-energy facets (red dots) with low indexed facets for four grains indexed with i=1… 4. In grain 1, a [02] surface facet can be formed by low energetic [010] and [00] (red symbols) surfaces as shown by the insets and observed in the tomogram.
Mentions: To convert column mass values into radians, we determined experimentally the phase changes of the electron wave caused by scattering at one gold atom and one MgO molecule (Methods). Table 1 lists these phase values. It is seen that the phase of the exit wave is changed by 0.21±0.07 rad by passing through a single gold atom in an atomic column or by 0.08±0.02 rad if it is passing through a single MgO molecule. A value of 0.11 rad for scattering at one Ge atom is estimated using a Z2/3 dependence. Remarkably, it is also seen that error bars increase with increasing dose rates, suggesting that measurements with a best element differentiation can only be performed if dose rates are kept low. In addition, column locations in the beam direction can be determined to a precision 1.2–2.4 Å on an absolute scale. Consequently, depth resolution has reached interatomic distances in thickness reconstructions from single projections. It is now straightforward to create 3D tomograms from these measurements, as the focus values describe the exit surface profile of the sample and the column length is given by the number of atoms of known spacing along the column length. In this manner, we have created the tomograms (Fig. 4) that show all geometrical properties that one expects to be imprinted by the chosen sample preparation procedure. The number of atoms in each tomogram is a time average that is dose rate dependent and equals 35,389 for Ge, 4,883 for Au and 10,750 (Mg, O) for MgO.

Bottom Line: Resolution and sensitivity of the latest generation aberration-corrected transmission electron microscopes allow the vast majority of single atoms to be imaged with sub-Ångstrom resolution and their locations determined in an image plane with a precision that exceeds the 1.9-pm wavelength of 300 kV electrons.The method is compatible with low dose rate electron microscopy, which improves on signal quality, while minimizing electron beam-induced structure modifications even for small particles or surfaces.We apply it to germanium, gold and magnesium oxide particles, and achieve a depth resolution of 1-2 Å, which is smaller than inter-atomic distances.

View Article: PubMed Central - PubMed

Affiliation: Department of Engineering and System Science, National Tsing-Hua University, 101 Kuang-Fu Road, Hsin Chu 300, Taiwan.

ABSTRACT
Resolution and sensitivity of the latest generation aberration-corrected transmission electron microscopes allow the vast majority of single atoms to be imaged with sub-Ångstrom resolution and their locations determined in an image plane with a precision that exceeds the 1.9-pm wavelength of 300 kV electrons. Such unprecedented performance allows expansion of electron microscopic investigations with atomic resolution into the third dimension. Here we report a general tomographic method to recover the three-dimensional shape of a crystalline particle from high-resolution images of a single projection without the need for sample rotation. The method is compatible with low dose rate electron microscopy, which improves on signal quality, while minimizing electron beam-induced structure modifications even for small particles or surfaces. We apply it to germanium, gold and magnesium oxide particles, and achieve a depth resolution of 1-2 Å, which is smaller than inter-atomic distances.

No MeSH data available.


Related in: MedlinePlus