Surface Disorder and Exfoliation in Lithographically Textured Molybdenum Disulfide

1986 ◽  
Vol 82 ◽  
Author(s):  
C. B. Roxlo ◽  
H. W. Deckman ◽  
J. H. Dunsmuir ◽  
A. F. Ruppert ◽  
R. R. Chianelli
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molybdenum Disulfide ◽  
Layered Structure ◽  
Single Layer ◽  
Chemical Treatments ◽  
Transmission Electron ◽  
Surface Disorder ◽  
Edge Surface

ABSTRACTLithographic techniques have been used to prepare transmission electron microscopy samples of MoS2, allowing examination of the edge surface with single-layer resolution. We observe that these surfaces are easily disordered by chemical treatments common in the catalysis industry. In some cases treatment in H2/H2S leads to an exfoliation of the layered structure, a process which can be observed as it occurs in the microscope.

Microstructure of SrTiO3 Thin Films as Single Layer and Incorporated in Yba2Cu3O7-x/SrTiO3 Multilayers

1995 ◽  
Vol 401 ◽  
Author(s):  
L. Ryen ◽  
E. Olssoni ◽  
L. D. Madsen ◽  
C. N. L. Johnson ◽  
X. Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Lattice Mismatch ◽  
Single Layer ◽  
Transmission Electron ◽  
Tilt Boundaries ◽  
Interfacial Dislocations ◽  
The Individual ◽  
Film Substrate

AbstractEpitaxial single layer (001) SrTiO3 films and an epitaxial Yba2Cu3O7-x/SrTiO3 multilayer were dc and rf sputtered on (110)rhombohedral LaAIO3 substrates. The microstructure of the films was characterised using transmission electron microscopy. The single layer SrTiO3 films exhibited different columnar morphologies. The column boundaries were due to the lattice mismatch between film and substrate. The boundaries were associated with interfacial dislocations at the film/substrate interface, where the dislocations relaxed the strain in the a, b plane. The columns consisted of individual subgrains. These subgrains were misoriented with respect to each other, with different in-plane orientations and different tilts of the (001) planes. The subgrain boundaries were antiphase or tilt boundaries.The individual layers of the Yba2Cu3O7-x/SrTiO3 multilayer were relatively uniform. A distortion of the SrTiO3 unit cell of 0.9% in the ‘001’ direction and a Sr/Ti ratio of 0.62±0.04 was observed, both in correspondence with the single layer SrTiO3 films. Areas with different tilt of the (001)-planes were also present, within each individual SrTiO3 layer.

scholarly journals Thickening of T1 Precipitates during Aging of a High Purity Al–4Cu–1Li–0.25Mn Alloy

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 30 ◽  
Author(s):  
Ines Häusler ◽  
Reza Kamachali ◽  
Walid Hetaba ◽  
Birgit Skrotzki
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Purity ◽  
External Load ◽  
Volume Fraction ◽  
Single Layer ◽  
Age Hardening ◽  
Defect Type ◽  
Transmission Electron

The age hardening response of a high-purity Al–4Cu–1Li–0.25Mn alloy (wt. %) during isothermal aging without and with an applied external load was investigated. Plate shaped nanometer size T1 (Al2CuLi) and θ′ (Al2Cu) hardening phases were formed. The precipitates were analyzed with respect to the development of their structure, size, number density, volume fraction and associated transformation strains by conducting transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) studies in combination with geometrical phase analysis (GPA). Special attention was paid to the thickening of T1 phase. Two elementary types of single-layer T1 precipitate, one with a Li-rich (Type 1) and another with an Al-rich (Defect Type 1) central layer, were identified. The results show that the Defect Type 1 structure can act as a precursor for the Type 1 structure. The thickening of T1 precipitates occurs by alternative stacking of these two elementary structures. The thickening mechanism was analyzed based on the magnitude of strain associated with the precipitation transformation normal to its habit plane. Long-term aging and aging under load resulted in thicker and structurally defected T1 precipitates. Several types of defected precipitates were characterized and discussed. For θ′ precipitates, a ledge mechanism of thickening was observed. Compared to the normal aging, an external load applied to the peak aged state leads to small variations in the average sizes and volume fractions of the precipitates.

Crystallization of Amorphous Si In Al/Si Multilayers

1991 ◽  
Vol 230 ◽  
Author(s):  
Toyohiko J. Konno ◽  
Robert Sinclair
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Layered Structure ◽  
Heat Of Reaction ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Amorphous Si

AbstractThe crystallization of amorphous Si in a Al/Si multilayer (with a modulation length of about 120Å) was investigated using transmission electron microscopy, differential scanning calorimetry and X-ray diffraction. Amorphous Si was found to crystallize at about 175 °C with the heat of reaction of 11±2(kJ/mol). Al grains grow prior to the nucleation of crystalline Si. The crystalline Si was found to nucleate within the grown Al layers. The incipient crystalline Si initially grows within the Al layer and then spreads through the amorphous Si and other Al layers. Because of extensive intermixing, the original layered structure is destroyed. The Al(111) texture is also enhanced.

Observation of a Layered Structure of Polymer Langmuir-Blodgett Films by Transmission Electron Microscopy

1995 ◽  
Vol 28 (10) ◽  
pp. 3736-3738 ◽  
Author(s):  
Shinzaburo Ito ◽  
Kenji Kawano ◽  
Masahide Yamamoto ◽  
Hirokazu Hasegawa ◽  
Takeji Hashimoto
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Layered Structure ◽  
Langmuir Blodgett ◽  
Transmission Electron ◽  
Langmuir Blodgett Films

scholarly journals Al2O3scale development on iron aluminides

2006 ◽  
Vol 21 (6) ◽  
pp. 1409-1419 ◽  
Author(s):  
X.F. Zhang ◽  
K. Thaidigsmann ◽  
J. Ager ◽  
P.Y. Hou
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
Nickel Aluminide ◽  
Single Layer ◽  
Photoluminescence Spectroscopy ◽  
Iron Aluminide ◽  
Transmission Electron ◽  
Main Components ◽  
Transient Phases

The structure and phase of the Al2O3scale that forms on an Fe3Al-based alloy Fe-28Al-5Cr (at.%) was investigated by transmission electron microscopy and photoluminescence spectroscopy. Oxidation was performed at 900 °C and 1000 °C for up to 190 min. Transmission electron microscopy revealed that single-layer scales were formed after short oxidation times. Electron diffraction was used to show that the scales are composed of nanoscale crystallites of the θ, γ, and α phases of alumina. Band-like structure was observed extending along three 120°-separated directions within the surface plane. Textured θ and γ grains were the main components of the bands, whereas mixed α and transient phases were found between the bands. Extended oxidation produced a double-layered scale structure with a continuous α layer at the scale/alloy interface and a γ/θ layer at the gas surface. The mechanism for the formation of Al2O3scales on iron aluminide alloys is discussed and compared with that for nickel aluminide alloys.

Microstructure and Current Transport Properties of YBa2Cu3O7-x/(Ba0.05, Sr0.95)TiO3 Multiple-Layer Thin Films

2003 ◽  
Vol 795 ◽  
Author(s):  
Y. Luo ◽  
R. A. Hughes ◽  
J. S. Preston ◽  
G. A. Botton
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Electrical Properties ◽  
Lattice Mismatch ◽  
Single Layer ◽  
Nanocomposite Films ◽  
Mismatch Strain ◽  
Multiple Layer ◽  
Transmission Electron

ABSTRACTYBa2Cu3O7-x (YBCO) films grown by pulsed laser deposition (PLD) on (100) LaAlO3 (LAO) substrates show a strong thickness dependence on the electrical properties. For example, for films in excess of 0.3 μm, the critical current density decreases with increasing thickness. In contrast, nano-composite films consisting of a series of multiple layers of YBa2Cu3O7-x and (Ba0.05, Sr0.95)TiO3 (BSTO) thin films having a total thickness of 5 μm show improved electrical properties. In order to understand this phenomenon, a detailed microstructural characterization has been undertaken. Transmission electron microscopy (TEM) observations show that cracks, stacking faults, c-║ crystals and secondary phase precipitates are present on the single-layer films, while a high-quality microstructure is observed for the nanocomposite multiple-layer films although defects at YBCO/BSTO interface are still present. In addition, nanocomposite films have a reduced surface roughness. In this complex microstructure, the YBCO/BSTO interfaces and the lattice mismatch strain play a crucial role in controlling the nature of the defects and stability of phases. In order to understand the role of the BSTO layer has on the microstructure, the interfacial mismatch strain and defects are analyzed by high-resolution transmission electron microscopy (HRTEM) in combination with the Moiré fringe technique.

Tem Study of Cvd‐Grown Bi‐Sr‐Ca‐Cu‐0 Thin Films on (001) Mgo Substrates

1989 ◽  
Vol 169 ◽  
Author(s):  
O. Ueda ◽  
T. Kimura ◽  
H. Yamawaki ◽  
M. Ihara ◽  
M. Ozeki
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Layered Structure ◽  
Transmission Electron ◽  
Different Thickness ◽  
Large Domains

AbstractCVD‐grown Bi‐Sr‐Ca‐Cu‐0 thin films on (OOl)MgO with T at 110 K have been investigated by transmission electron microscopy. The films are found to consist of large domains oriented along the c‐axis, with diameters of 15‐100 um. These domains exhibit incommensurate superstructures along the fa‐axis. In addition, we have observed similar superstructure spots in two equivalent directions normal to each other. It has also been found that the interface between the thin film and the substrate is very abrupt. Five different perovskite‐related layers along the c‐axis with different thickness are present. In the thin film, 80K phases are dominant and 110 K phases are less likely. Three other phases are very rarely observed. Furthermore, boundaries where the layered structure is different on both sides are often found.

Microstructural evolution during pyrolysis of triol-based sol-gel single-layer Pb(Zr0.53Ti0.47)O3 thin films

2002 ◽  
Vol 17 (8) ◽  
pp. 2066-2074 ◽  
Author(s):  
Zhaoxia Zhou ◽  
Ian M. Reaney ◽  
David Hind ◽  
Steven J. Milne ◽  
Andy P. Brown ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Microstructural Evolution ◽  
Sol Gel ◽  
Pyrochlore Phase ◽  
Single Layer ◽  
Face Centered Cubic ◽  
Analytical Transmission Electron Microscopy ◽  
Transmission Electron

Advanced analytical transmission electron microscopy has been used to investigate microstructural evolution during pyrolysis in triol-based sol-gel thin films. At pyrolysis temperatures up to 300 °C, the films remained amorphous; however, nanometer-sized precipitates were observed in films heat-treated up to 400 °C for 10 min. Analytical transmission electron microscopy indicated that the precipitates were Pb-rich, as well as deficient in O, Ti, and Zr. Films pyrolyzed up to 500 °C for 10 min were composed of a nanocrystalline pyrochlore phase; however, pores could be observed, situated in the same position as the nanometer-sized precipitates at 400 °C. Face-centered cubic Pb-rich crystallites were also present on the surface of pyrolyzed films but absent in the fully crystallized films annealed at 650 °C. A tentative mechanism is proposed to explain these observations.

Simulation Study of Aberration-Corrected High-Resolution Transmission Electron Microscopy Imaging of Few-Layer-Graphene Stacking

2010 ◽  
Vol 16 (2) ◽  
pp. 194-199 ◽  
Author(s):  
Florence Nelson ◽  
Alain C. Diebold ◽  
Robert Hull
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Random Noise ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Microscopy Imaging ◽  
Layer Graphene ◽  
Transmission Electron ◽  
Aberration Corrected

AbstractGraphene is a single layer of carbon atoms arranged in a hexagonal lattice. The high carrier mobility and mechanical robustness of single layer graphene make it an attractive material for “beyond CMOS” devices. The current work investigates through high-resolution transmission electron microscopy (HRTEM) image simulation the sensitivity of aberration-corrected HRTEM to the different graphene stacking configurations AAA/ABA/ABC as well as bilayers with rotational misorientations between the individual layers. High-angle annular dark field–scanning transmission electron microscopy simulation is also explored. Images calculated using the multislice approximation show discernable differences between the stacking sequences when simulated with realistic operating parameters in the presence of low random noise.

The sporulation process in Thermomonospora fusca as revealed by scanning and transmission electron microscopy

1977 ◽  
Vol 23 (8) ◽  
pp. 1088-1095 ◽  
Author(s):  
Don. L. Crawford ◽  
Matthew A. Gonda
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Smooth Surface ◽  
Single Layer ◽  
Spore Coat ◽  
Thermomonospora Fusca ◽  
Transmission Electron ◽  
Aerial Hyphae ◽  
Sporulation Process

The sporulation process in the thermophilic actinomycete Thermomonospora fusca was observed by scanning and transmission electron microscopy. As shown by scanning electron microscopy, spores were produced primarily on aerial hyphae and first appeared as bud-like enlargements at the tips of short multibranched sporophores. Young spores were oval to spherical in shape with a smooth surface. As they matured spores enlarged and developed a rough and globular covering, which was quite fragile and easily detached from the spore. This outer layer, as observed by transmission electron microscopy, was thought equivalent to the sheath of other Thermomonospora species. In cross section, mature spores exhibited a thick spore coat underneath the outer globular layer. This spore coat was usually observed as a single layer, but some spores produced a bilayered coat. No multilayered spore coat or spore cortex was observed in the heat-sensitive spores of T. fusca. They were, therefore, shown to be aleuriospores (microcondia), and not endospores.

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