Search results for "TRANSMISSION ELECTRON"
showing 10 items of 426 documents
In-situ small-angle x-ray scattering study of nanoparticles in the plasma plume induced by pulsed laser irradiation of metallic targets
2012
Import JabRef; International audience; Small angle x-ray scattering was used to probe in-situ the formation of nanoparticles in the plasma plume generated by pulsed laser irradiation of a titanium metal surface under atmospheric conditions. The size and morphology of the nanoparticles were characterized as function of laser irradiance. Two families of nanoparticles were identified with sizes on the order of 10 and 70 nm, respectively. These results were confirmed by ex-situ transmission electron microscopy experiments.
Blistering mechanisms of atomic-layer-deposited AlN and Al2O3 films
2017
Blistering of protective, structural, and functional coatings is a reliability risk pestering films ranging from elemental to ceramic ones. The driving force behind blistering comes from either excess hydrogen at the film-substrate interface or stress-driven buckling. Contrary to the stress-driven mechanism, the hydrogen-initiated one is poorly understood. Recently, it was shown that in the bulk Al-Al2O3 system, the blistering is preceded by the formation of nano-sized cavities on the substrate. The stress-and hydrogen-driven mechanisms in atomic-layer-deposited (ALD) films are explored here. We clarify issues in the hydrogen-related mechanism via high-resolution microscopy and show that at…
Three-dimensional subnanoscale imaging of unit cell doubling due to octahedral tilting and cation modulation in strained perovskite thin films
2019
Determining the three-dimensional (3D) crystallography of a material with subnanometer resolution is essential to understanding strain effects in epitaxial thin films. A scanning transmission electron microscopy imaging technique is demonstrated that visualizes the presence and strength of atomic movements leading to a period doubling of the unit cell along the beam direction, using the intensity in an extra Laue zone ring in the back focal plane recorded using a pixelated detector method. This method is used together with conventional atomic resolution imaging in the plane perpendicular to the beam direction to gain information about the 3D crystal structure in an epitaxial thin film of La…
Ion irradiation of carbon nanotubes encapsulating cobalt crystals
2008
Abstract The response of multi-walled carbon nanotubes encapsulating Co nanorods to ion irradiation was studied. The irradiation experiments with medium ion energies (40–500 keV) were carried out at high temperatures and combined with transmission electron microscopy and Raman characterization of the irradiated samples. Contrary to electron irradiation and high-energy (100 MeV) ion irradiation, we did not see accumulation of pressure inside irradiated nanotubes. We found that nanotubes with Co nanorods inside were transformed to amorphous carbon rods encapsulating Co clusters with typical diameters of 3–6 nm. As Co is magnetic, such one-dimensional composite systems could be used for variou…
Second-harmonic Generation Microscopy of Carbon Nanotubes
2012
We image an individual single-walled carbon nanotube (SWNT) by second-harmonic generation (SHG) and transmission electron microscopy and propose that SHG microscopy could be used to probe the handedness of chiral SWNTs.
Powder metallurgy processing and deformation characteristics of bulk multimodal nickel
2014
cited By 7; International audience; Spark plasma sintering was used to process bulk nickel samples from a blend of three powder types. The resulting multimodal microstructure was made of coarse (average size ∼ 135 μm) spherical microcrystalline entities (the core) surrounded by a fine-grained matrix (average grain size ∼ 1.5 μm) or a thick rim (the shell) distinguishable from the matrix. Tensile tests revealed yield strength of ∼ 470 MPa that was accompanied by limited ductility (∼ 2.8% plastic strain). Microstructure observation after testing showed debonding at interfaces between the matrix and the coarse entities, but in many instances, shallow dimples within the rim were observed indica…
Low melting Metal Catalysed Growth of Tin Disulfide Nanotubes
2009
AbstractWe report here the synthesis of tin disulfide nanotubes by a vapour liquid solid growth using bismuth, a low melting metal, as a catalyst. The reaction was carried out in a single step process by heating SnS2 and bismuth in a horizontal tube furnace at 800oC. TEM analysis allowed proposing a plausible mechanism for the formation of SnS2 nanotubes. Pure material could be obtained by optimizing the reaction based on a product analysis using powder X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) combined with energy dispersive X-ray spectroscopy (EDX).
Influence of ZnO/graphene nanolaminate periodicity on their structural and mechanical properties
2018
International audience; Structural, electronic and mechanical properties of ZnO/Graphene (ZnO/G) nanolaminates fabricated by low temperature atomic layer deposition (ALD) and chemical vapor deposition (CVD) were investigated. We performed scanning and transmission electron microscopy (SEM/TEM), X-ray diffraction (XRD), electron energy loss spectroscopy (EELS), Raman spectroscopy, X-Ray photoelectron spectroscopy (XPS) and nanoindentation to characterize the ZnO/G nanolaminates. The main structural and mechanical parameters of ZnO/G nanolaminates were calculated. The obtained results were analyzed and interpreted taking into account mechanical interaction and charge effects occurring at the …
Structural Characterization of Organics Using Manual and Automated Electron Diffraction
2010
In the last decade the importance of transmission electron microscopic studies has become increasingly important with respect to the characterization of organic materials, ranging from small organic molecules to polymers and biological macromolecules. This review will focus on the use of transmission electron microscope to perform electron crystallography experiments, detailing the approaches in acquiring electron crystallographic data. The traditional selected area approach and the recently developed method of automated diffraction tomography (ADT) will be discussed with special attention paid to the handling of electron beam sensitive organic materials.
Surface reconstruction of the lamellar morphology in a symmetric poly(styrene-block-butadiene-block-methyl methacrylate) triblock copolymer: A tappin…
1996
The surface morphology of a symmetric poly(styrene-block-butadiene-block-methyl methacrylate) triblock copolymer (PS-b-PB-b-PMMA) with 6 wt % PB has been investigated by tapping mode scanning force microscopy (SFM). The results are compared to the bulk morphology as determined by transmission electron microscopy (TEM). In solvent-cast films PS/PMMA lamellae are formed, which are oriented nearly perpendicular to the free surface. Like in the bulk, also at the free film surface polybutadiene spheres are located at the lamellar PS/PMMA interface. However, contrary to the bulk, the surface morphology includes a large number of defects such as curved lamellar and disclinations, and the lamellar …