Chromatic Aberration Correction by Combination Concave Lens

Sawada, Hidetaka; Hosokawa, Fumio; Sasaki, Takeo; Yuasa, Shinji; Kawazoe, M; Terao, Mitsuhisa; Kaneyama, T.; Kondo, Yukihito; Kimoto, Koji; Suenaga, Kazu

doi:10.1017/s1431927610059507

Cited by 3 publications

(3 citation statements)

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“…In recent years, significant progress has been made in transmission electron microscopy (TEM), driven by the development of aberration correctors (Haider et al, 1998; Kabius et al, 2009; Sawada et al, 2010) and other electron optical components such as monochromators and high brightness guns (Freitag et al, 2008; Tiemeijer et al, 2012). Leading-edge equipment allows now for single atom detection across the Periodic Table of Elements at an ultimate resolution limit around 0.5 Å, which is set by the Coulomb scattering process itself (Kisielowski et al, 2008, 2009; Alem et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

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Atomic Resolution Phase Contrast Imaging and In-Line Holography Using Variable Voltage and Dose Rate

Barton

Jiang²,

Cheng

et al. 2012

Microsc Microanal

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The TEAM 0.5 electron microscope is employed to demonstrate atomic resolution phase contrast imaging and focal series reconstruction with acceleration voltages between 20 and 300 kV and a variable dose rate. A monochromator with an energy spread of ≤0.1 eV is used for dose variation by a factor of 1,000 and to provide a beam-limiting aperture. The sub-Ångstrøm performance of the instrument remains uncompromised. Using samples obtained from silicon wafers by chemical etching, the [200] atom dumbbell distance of 1.36 Å can be resolved in single images and reconstructed exit wave functions at 300, 80, and 50 kV. At 20 kV, atomic resolution <2 Å is readily available but limited by residual lens aberrations at large scattering angles. Exit wave functions reconstructed from images recorded under low dose rate conditions show sharper atom peaks as compared to high dose rate. The observed dose rate dependence of the signal is explained by a reduction of beam-induced atom displacements. If a combined sample and instrument instability is considered, the experimental image contrast can be matched quantitatively to simulations. The described development allows for atomic resolution transmission electron microscopy of interfaces between soft and hard materials over a wide range of voltages and electron doses.

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Section: Introductionmentioning

confidence: 99%

“…In recent years, significant progress has been made in transmission electron microscopy~TEM!, driven by the development of aberration correctors~Haider et al., 1998;Kabius et al, 2009;Sawada et al, 2010! and other electron optical components such as monochromators and high brightness guns~Freitag et Tiemeijer et al, 2012!.…”

Section: Introductionmentioning

confidence: 99%

Atomic Resolution Phase Contrast Imaging and In-Line Holography Using Variable Voltage and Dose Rate

Barton

Jiang²,

Cheng

et al. 2012

Microsc Microanal

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“…The recent past has witnessed tremendous gains in the capabilities of transmission electron microscopy (TEM) for exploring the atomic configuration of materials, largely because of dramatic improvements in the correction of lens aberrations. − It is now possible to obtain atomic-resolution images even of light-element materials, with a reduction in radiation damage effected by the utilization of reduced acceleration voltages (see, for example, refs – ). Our understanding of carbon systems, such as graphene or carbon nanotubes, has significantly benefitted from these instrumental developments.…”

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confidence: 99%

Transformations of Carbon Adsorbates on Graphene Substrates under Extreme Heat

et al. 2011

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We describe new phenomena of structural reorganization of carbon adsorbates as revealed by in situ atomic-resolution transmission electron microscopy (TEM) performed on specimens at extreme temperatures. In our investigations, a graphene sheet serves as both a quasi-transparent substrate for TEM and as an in situ heater. The melting of gold nanoislands deposited on the substrate surface is used to evaluate the local temperature profile. At annealing temperatures around 1000 K, we observe the transformation of physisorbed hydrocarbon adsorbates into amorphous carbon monolayers and the initiation of crystallization. At temperatures exceeding 2000 K the transformation terminates in the formation of a completely polycrystalline graphene state. The resulting layers are bounded by free edges primarily in the armchair configuration.

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