Effect of Sulfur Evaporation Rate on Screw Dislocation Driven Growth of MoS2with High Atomic Step Density

2016 ◽  
Vol 16 (12) ◽  
pp. 7145-7154 ◽  
Author(s):  
Pawan Kumar ◽  
B. Viswanath
Keyword(s):  
Screw Dislocation ◽  
Evaporation Rate ◽  
Atomic Step ◽  
Step Density

Dependence of Process Characteristics on Atomic-Step Density in Catalyst-Referred Etching of 4H–SiC(0001) Surface

2011 ◽  
Vol 11 (4) ◽  
pp. 2928-2930 ◽  
Author(s):  
Takeshi Okamoto ◽  
Yasuhisa Sano ◽  
Kazuma Tachibana ◽  
Kenta Arima ◽  
Azusa N. Hattori ◽  
...  
Keyword(s):  
Atomic Step ◽  
Process Characteristics ◽  
Step Density

Atomic-Step-Induced Screw-Dislocation-Driven Spiral Growth of SnS

2020 ◽  
Author(s):  
Yih-Ren Chang ◽  
Naoki Higashitarumizu ◽  
Hayami Kawamoto ◽  
Fu-Hsien Chu ◽  
Chien-Ju Lee ◽  
...  
Keyword(s):  
Screw Dislocation ◽  
Spiral Growth ◽  
Atomic Step

scholarly journals Screw-Dislocation-Driven Hierarchical Superstructures of Ag-Ag2O-AgO Nanoparticles

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1084
Author(s):  
Hua Yang ◽  
Jing Ru Zhang ◽  
Wentao Cao ◽  
Jin Zhen ◽  
Ji Hong Wu
Keyword(s):  
Screw Dislocation ◽  
Uv Irradiation ◽  
Growth Mechanism ◽  
Irradiation Time ◽  
Structural Evolution ◽  
Physiochemical Properties ◽  
Promising Strategy ◽  
Photochemical Method ◽  
Step Density ◽  
Average Size

Constructing multi-dimensional hierarchical superstructures has been, for a longtime, regarded as a promising strategy for modifying the physiochemical properties of nanomaterials. Guided by this rule, this work reports the synthesis of hierarchical superstructures of Ag-Ag2O-AgO nanoparticles (HSANs) using a convenient and surfactant-less photochemical method under 254 nm UV-irradiation. The formation of the HSANs superstructures is dominated by screw-dislocation-driven growth mechanism at low supersaturation condition. The structural evolution of the HSANs superstructures has been systematically investigated. The average size of the HSANs superstructures increased with prolonged 254 nm UV-irradiation. The step density on the superstructure surfaces also increased along with the 254 nm UV-irradiation time.

Comparative Study of Interface Structure in GaAs/AlAs Superlattices By Tem and Raman Scattering

1987 ◽  
Vol 102 ◽  
Author(s):  
T. Nakamura ◽  
M. Ikeda ◽  
S. Muto ◽  
S. Komiya ◽  
I. Umebu
Keyword(s):  
Raman Scattering ◽  
Interface Structure ◽  
Atomic Step ◽  
Transition Layers ◽  
Bright Spots ◽  
Transmission Electron ◽  
Scattering Measurements ◽  
Step Density ◽  
Raman Characterization ◽  
Growth Temperature Dependence

ABSTRACTTransition layers in GaAs/AlAs superlattices were studied by high resolution transmission electron microscopy (HRTEM) observations and Raman scattering measurements. We clarified that arrays of bright spots at the interface in the TEM image is a good indicator of the interfacial configuration and that a high atomic step density with intervals of less than 10 nm is necessary for Raman characterization using confined LO phonons.We characterized the growth temperature dependence of the transition layers at the GaAs/AlAs interfaces. For a sample grown at 500'C, the extent of the transition layers is about one monolayer and that of the interfacial step intervals is more than 10 nm. For a sample grown at 700 0 C, these values are about two monolayers and less than 3 nm, respectively.

Surface and Interfacial Topography of Oxides on Si(111) With Ultra-Low Atomic Step Density

1999 ◽  
Vol 592 ◽  
Author(s):  
Antonio C. Oliver ◽  
Jack M. Blakely
Keyword(s):  
Initial Step ◽  
Oxide Thickness ◽  
Interface Roughness ◽  
Oxide Surface ◽  
Atomic Step ◽  
Layer By Layer ◽  
Initial Oxidation ◽  
Atomic Steps ◽  
Si Substrates ◽  
Step Density

ABSTRACTAtomic force microscopy has been used to study the morphology of the oxide surface and the Si-SiO2 interface after oxidation of Si(111) surfaces that are either totally free of atomic steps or have well characterized low step density. The step-free areas were formed by thermally processing a patterned Si surface in which flat areas are enclosed by a square array of ridges; flow of the atomic steps into the surrounding ridge barriers produces a regular array of step-free areas each of which can be up to ∼50µm×50µm. Arrays of widely spaced steps (e.g. 5µm) can also be produced in the step-free areas. AFM scans of the same areas were taken prior to (dry) oxidation, after oxidation, and after chemical removal of the oxide. It was found that at an oxide thickness in the 5-13nm range, the initial step structure of the underlying Si substrates is translated through the oxide to the surface after oxidation with the oxide surface being somewhat rougher than the initial substrate. Furthermore, the initial step morphology of the substrate remains at the Si-SiO2 interface after etching away the oxide by HF. The interface roughness is less than that of the oxide surface. The results suggest that the initial oxidation of silicon proceeds in a ‘layer by layer’ manner and not through a preferential step-flow oxide growth mode.

A New Defect in Polyethylene Single Crystals

1973 ◽  
Vol 31 ◽  
pp. 70-71
Author(s):  
E. L. Thomas ◽  
S. L. Sass
Keyword(s):  
Single Crystals ◽  
Screw Dislocation ◽  
Small Distance ◽  
Dipole Model ◽  
Dislocation Dipole ◽  
Chain Folding ◽  
Black And White ◽  
Polymer Crystal ◽  
Different Types

In polyethylene single crystals pairs of black and white lines spaced 700-3,000Å apart, parallel to the [100] and [010] directions, have been identified as microsector boundaries. A microsector is formed when the plane of chain folding changes over a small distance within a polymer crystal. In order for the different types of folds to accommodate at the boundary between the 2 fold domains, a staggering along the chain direction and a rotation of the chains in the plane of the boundary occurs. The black-white contrast from a microsector boundary can be explained in terms of these chain rotations. We demonstrate that microsectors can terminate within the crystal and interpret the observed terminal strain contrast in terms of a screw dislocation dipole model.

Hole Formation in Gold Films

1972 ◽  
Vol 30 ◽  
pp. 510-511
Author(s):  
R. W. Vook ◽  
R. Cook ◽  
R. Ziemer
Keyword(s):  
Deposition Rate ◽  
Quartz Crystal ◽  
Evaporation Rate ◽  
Gold Films ◽  
Hole Density ◽  
Hole Formation ◽  
Microscope Slide ◽  
Crystal Film ◽  
Glass Microscope Slide ◽  
Glass Microscope

During recent experiments on Au films, a qualitative correlation between hole formation and deposition rate was observed. These early studies were concerned with films 80 to 1000A thick deposited on glass at -185°C and annealed at 170°C. In the present studies this earlier work was made quantitative. Deposition rates varying between 5 and 700 A/min were used. The effects of deposition rate on hole density for two films 300 and 700A thick were investigated.Au was evaporated from an outgassed W filament located 10 cm from a glass microscope slide substrate and a quartz crystal film thickness monitor. A shutter separating the filament from the substrate and monitor made it possible to obtain a constant evaporation rate before initiating deposition. The pressure was reduced to less than 1 x 10-6 torr prior to cooling the substrate with liquid nitrogen. The substrate was cooled in 15 minutes during which the pressure continued to drop to the mid 10-7 torr range, where deposition was begun.

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