A 2-2-2 200kv Field Emission STEM/TEM System

Boyes, E.D.; Ringnalda, J.; Stam, M.; Fliervoet, T F; Cappellen, E. Van

doi:10.1017/s1431927600027239

Cited by 6 publications

(4 citation statements)

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“…We carried out HRTEM studies of the pristine and doped samples using a novel Tecnai high resolution HR(S)TEM instrument equipped with a 200 kV field emission gun (FEG). 19,20 This HR(S)TEM instrument has an objective lens spherical aberration coefficient (C s ) of 0.5 mm and an electron wavelength (l) of 0.0025 nm. A double-tilt sample stage in the HRTEM provides tilting of crystals in the sample to 124u or 224u and crystals can be oriented to specific crystallographic zone axes for imaging and electron diffraction.…”

Section: Methodsmentioning

confidence: 99%

Structural systematics in boron-doped single wall carbon nanotubes

et al. 2004

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We report atomic level high resolution transmission electron microscopy (HRTEM), electron nanodiffraction and nano-electron energy loss spectroscopy (nano-EELS) of boron-doped carbon nanostructures obtained by laser ablation of Co/Ni/B-doped carbon targets. The observations provide direct evidence for structural systematics and atomic structural defects as a function of the B content in the target. Targets with low B concentration (below 3 at%), produced ropes of single wall carbon nanotubes (SWCNTs) with no detectable boron present in the SWCNT ropes. However, unintended N-doping of the curved honeycomb lattice was observed in the 2.5 at% B sample (which is attributed to the possible presence of small amounts of N in the targets or reaction environments), with striking consequences for doping of heteroatoms within the hexagonal lattice of the graphene layer. At higher B concentration (3.5 at% and higher), there are significant changes in the nanostructure, which exhibits defective graphite layers and a small number of double wall carbon nanotubes (DWCNTs). At the higher B concentration, boron-doping is evidenced in the form of very small amorphous B clusters trapped in graphite-like defective sites.

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Section: Methodsmentioning

confidence: 99%

Structural systematics in boron-doped single wall carbon nanotubes

et al. 2004

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“…22 Both the atomic resolution ETEM in controlled gas and liquid environments and the 2-2-2 FE(S)TEM are providing new opportunities in the atomic structural and chemical studies of nanomaterials. [22][23][24] Samples of Au nanorods were supported on carbon filmed Cu grids for electron microscopy. In addition to atomic structures, we carried out complex nanodiffraction studies from single nanorods using nanoelectron probes in the FE(S)TEM.…”

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confidence: 99%

“…We investigated atomic structures of the surfaces of the nanorods using a novel atomic resolution environmental transmission electron microscope (ETEM) capable of operating in gas/vacuum/liquid environments and at different temperatures − attached with a scanning-TEM (STEM) system, and a novel field emission gun Tecnai (FE-(S)TEM), using electron accelerating voltage of 200 keV. Powerful FE STEM/TEM, the so-called 2-2-2 200 keV field emission Tecnai STEM/TEM, combines atomic resolution imaging with atomic level chemical and crystallographic analyses with 2 Å (0.2 nm) resolution in each of the TEM, STEM, and chemical analyses modes (hence 2-2-2) . Both the atomic resolution ETEM in controlled gas and liquid environments and the 2-2-2 FE(S)TEM are providing new opportunities in the atomic structural and chemical studies of nanomaterials. − Samples of Au nanorods were supported on carbon filmed Cu grids for electron microscopy.…”

mentioning

confidence: 99%

“…Powerful FE STEM/TEM, the so-called 2-2-2 200 keV field emission Tecnai STEM/TEM, combines atomic resolution imaging with atomic level chemical and crystallographic analyses with 2 Å (0.2 nm) resolution in each of the TEM, STEM, and chemical analyses modes (hence 2-2-2) . Both the atomic resolution ETEM in controlled gas and liquid environments and the 2-2-2 FE(S)TEM are providing new opportunities in the atomic structural and chemical studies of nanomaterials. − Samples of Au nanorods were supported on carbon filmed Cu grids for electron microscopy. In addition to atomic structures, we carried out complex nanodiffraction studies from single nanorods using nanoelectron probes in the FE(S)TEM.…”

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confidence: 99%

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Surface Atomic Defect Structures and Growth of Gold Nanorods

2002

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We present atomic and defect structural studies of technologically important gold nanorods synthesized by a wet chemical process. Our surface atomic structural studies and electron nanodiffraction from single nanorods have provided the first direct evidence of the stabilization of the highly unstable (110) surface by surfactant molecules. The insights into surface defect structures have important implications in the applications of nanorods in the molecular device technology. The origin and the development of the growth process of nanorods have been inferred from the results.

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Benefits of microscopy with super resolution

Kisielowski

Principe

Freitag³

et al. 2001

Physica B: Condensed Matter

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Transmission Electron Microscopy developed from an imaging tool into a quantitative electron beam characterization tool that locally accesses structure, chemistry, and bonding in materials with sub Angstrom resolution. Experiments utilize coherently and incoherently scattered electrons. In this contribution, the interface between gallium nitride and sapphire as well as thin silicon gate oxides are studied to understand underlying physical processes and the strength' of the different microscopy techniques. An investigation of the GaN/sapphire interface benefits largely from the application of phase contrast microscopy that makes it possible to visualize dislocation core structures and single columns of oxygen and nitrogen at a closest spacing of 85 pm. In contrast, it is adequate to investigate Si/SiO x N y /poly-Si interfaces with incoherently scattered electrons and electron spectroscopy because amorphous and poly crystalline materials are involved. Here, it is demonstrated that the SiO x N y /poly-Si interface is rougher than the Si/SiO x interface, that desirable nitrogen diffusion gradients can be introduced into the gate oxide, and that a nitridation coupled with annealing increases its physical width while reducing the equivalent electrical oxide thickness to values approaching 1.2 nm. Therefore, an amorphous SiN x O y gate dielectric seems to be a suitable substitute for traditional gate oxides to further increase device speed by reducing dimensions in Si technology.

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A 2-2-2 200kv Field Emission STEM/TEM System

Cited by 6 publications

References 0 publications

Structural systematics in boron-doped single wall carbon nanotubes

Structural systematics in boron-doped single wall carbon nanotubes

Surface Atomic Defect Structures and Growth of Gold Nanorods

Benefits of microscopy with super resolution

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