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IMPROVED SIZE HOMOGENEITY OF INP-ON-GAINP STRANSKI-KRASTANOW ISLANDS BY GROWTH ON A THIN GAP INTERFACE LAYER

Coherent InP nano-sized islands, embedded into GaInP, have been grown by metal-organic vapour phase epitaxy using the Stranski-Krastanow growth mode. Photoluminescence, atomic force microscopy and transmission electron microscopy studies show that the insertion of a thin similar to 4 monolayer thick GaP layer affects the critical thickness of the subsequently deposited two-dimensional InP wetting Coherent InP nano-sized islands, embedded into GaInP, have been grown by metal-organic vapour phase epitaxy using the Stranski-Krastanow growth mode. Photoluminescence, atomic force microscopy and transmission electron microscopy studies show that the insertion of a thin ∼ 4 monolayer thick GaP layer affects the critical thickness of the subsequently deposited two-dimensional InP wetting layer, in

TRANSMISSION ELECTRON-MICROSCOPY INVESTIGATION OF THE MORPHOLOGY OF INP STRANSKI-KRASTANOW ISLANDS GROWN BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION

We have used transmission electron microscopy to determine the morphology of InP Stranski-Krastanow islands in GaInP, grown by metalorganic chemical vapor deposition at 580 degrees C. We investigated both capped and uncapped islands. It was found that the fully developed islands have the principal shape of truncated pyramids with a hexagonal base both before and after overgrowth. The planes definiWe have used transmission electron microscopy to determine the morphology of InP Stranski–Krastanow islands in GaInP, grown by metalorganic chemical vapor deposition at 580 °C. We investigated both capped and uncapped islands. It was found that the fully developed islands have the principal shape of truncated pyramids with a hexagonal base both before and after overgrowth. The planes defining the

Microdomains, Solid Solutions and the "Defect Fluorite" to C-Type Sesquioxide Transition in CeO2-RO1.5 and ZrO2-RO1.5 Systems

Satellite dark field (SDF) imaging is used to show that there is a definite change in symmetry on moving across the two-phase region separating the so-called "defect fluorite" and C-type sesquioxide solid solution regions in (1 - x)CeO2 · xRO1.5 and (1 - x )ZrO2 · xRO1.5 systems. SDF images of the "defect fluorite" side of the two-phase region are characterized by a microdomain texture on the ∼100

In-situ grown dots of InP on GaAs and GaInP - A comparison

Shape, size and density of dots of InP on GaInP and GaAs surfaces, formed in-situ by the strain-induced phase transition from a two-dimensional (Frank-Van der Merwe) into a three-dimensional layer+islands (Stranski-Krastanow) morphology, are investigated. The observations support models which include the kinetics of island formation as important ingredients to explain the rather high size homogene

Kinetics of ethylene oxidation on plane Pt/SiO2 catalysts in the viscous pressure regime: Evidence of support activity

C2H4 oxidation on plane Pt/SiO2 model catalysts with various Pt loadings was studied at T = 373-473 K and in the pressure ranges 10-6-102 Torr C2H4 and 0.3-1500 Torr O2 (1 Torr = 133.3 Pa). Mass spectrometry combined with spatially resolved gas sampling enabled kinetic data to be collected far into the viscous pressure regime. Reaction orders and activation energies were similar to those of a macr

Growth and electronic properties of epitaxial TiN thin films on 3C-SiC(001) and 6H-SiC(0001) substrates by reactive magnetron sputtering

Epitaxial TiN films were grown on cubic (3C)-SiC(001) and hexagonal (6H)-SiC(0001) substrates by ultrahigh vacuum reactive magnetron sputtering from a Ti target in a mixed Ar and N2 discharge at a substrate temperature of 700°C. Cross-sectional transmission electron microscopy, including high-resolution imaging, showed orientational relationships TiN(001) ∥ 3C-SiC(001), and TiN[110] ∥ 3C-SiC[110],

Compositional information from amorphous Si-Ge multilayers using high-resolution electron microscopy imaging and direct digital recording

A simple method for extracting compositional information from high-resolution electron microscopy images of an amorphous two-element system using a slow-scan CCD camera has been developed. The method has been evaluated on amorphous Si/Ge multilayers. The characterisation of the multilayers provided information about thickness of the layers, maximum concentrations within the layers and elemental pr

Strain relaxation and thermal stability of the 3C-SiC(001)/Si(001) interface : A molecular dynamics study

Molecular dynamics (MD) and high-resolution electron microscopy (HREM) imaging are used to investigate the mechanism of strain relaxation of a model 3C-SiC(001)/Si(001) interface. It is found that the essential atomic mechanism governing this process is the formation of undulations in planes parallel and perpendicular to the interface. The net effect is the generation of misfit-accommodating dislo

A new silicon phosphide, Si12P5 : Formation conditions, structure, and properties

The formation conditions, structure, and properties of the recently discovered phosphide, Si12P5 (initially assigned Si7P3), have been studied using x-ray diffraction, high-resolution transmission electron microscopy, photospectrometry, and a four-point probe. The phosphide formed in amorphous Si-P alloy thin films with 30, 35 and 44 at. % P after annealing at 1000°C for 30 min. During annealing a

Digital HREM imaging of yttrium atoms in YB56 with YB66 structure

The arrangement of yttrium atoms in YB56with YB66structure was determined by high-resolution electron microscopy (HREM) using a slow-scan CCD camera. Digital HREM images recorded along the [100], [110], and [111] directions of the YB56crystals showed "averaged" yttrium atom positions in the boron clusters, which were also confirmed by image simulation. Digital HREM images recorded from thin region

Trump, Clinton, and the gendering of newspaper discourse about the 2016 US presidential election debates

Electoral politics remains a much-gendered sphere, dominated by men political actors and masculine behaviors. Media coverage of politics has often reinforced gendered norms. This article uses qualitative thematic analysis of three U.S. newspapers’ coverage of the 2016 presidential debates between Donald Trump and Hillary Clinton to explore how the mediated construction of political leaders is gend

Structural and electrical properties of superconducting Nb/Si multilayers

We have found the deposition technology at which the interface roughness of Nb/Si multilayer is strongly correlated and decreases with deposited layer number. On the basis of our Nb/Si multilayer we succeeded to prepare ten-fold stacked Josephson junction (JJ). Basic electric properties of stacked JJ are presented.

The first structure determination of nanosized colloidal particles of Pd3P by high-resolution electron microscopy

The exact three-dimensional structure of a nanosized colloidal particle of Pd3P was determined directly from high-resolution transmission electron microscopy (HRTEM) images that were recorded in several crystallographic directions. An HRTEM image recorded along [011] is shown on the right. The cores of the particles were excluded from the analysis because of severe multiple diffraction.

Women, Language and Politics, Sylvia Shaw, Cambridge University Press, Cambridge (2020)

This timely book addresses the political under-representation of women and over-representation of men, both in the UK and internationally. It does so by bringing together perspectives from political science and sociolinguistics to analyse the relationship between gender and language in a variety of political spheres. Specifically, it investigates how both women and men use language and interact ac

Strain state in semiconductor quantum dots on surfaces : a comparison of electron microscopy and finite element calculations

The strain distribution in InP quantum dots, coherently grown on a GaInP substrate, was determined by image analysis of high-resolution electron microscopy images. Image simulations were used to verify the obtained results. The measured strain values were compared with values obtained from finite element calculations, using the dot shape determined by electron microscopy. The measured and calculat

Reduction of surface sulphur upon microbial devulcanization of rubber materials

Thiobacillus ferrooxidans, T. thioparus, Acidianus brierleyi and TH2 Lund, an archaeal isolate, were tested for sulphur oxidising capacity on ground rubber from spent car tyres. T. ferrooxidans converted 8% (w/w) of the sulphur in cryo-ground spent rubber to sulphate in 20 days. Desulphurization of fresh made natural rubber was studied with scanning electron microscope with energy-dispersive x-ray

Carbon nitride nanotubulite - densely-packed and well-aligned tubular nanostructures

Tubular carbon nitride (CNx, x=0.01–0.32) nanoparticles were successfully synthesized by d.c. magnetron sputtering. These tubes were grown in a highly packed form perpendicularly on a sodium chloride substrate. Their number density is estimated to be ∼1×104 per μm2 and is constant over macroscopic regions. Sub-nanometer scale chemical mapping shows that the nitrogen to carbon atomic ratio is rathe

Crystal chemistry and defect structure of ekmanite : New data from transmission electron microscopy and Mossbauer spectroscopy

Ekmanite is a member of the 2:1 type modulated layer silicates such as ganophyllite and bannisterite. Its chemical composition can be represented by K(M20)[Si32O76](OH)16 (M = Fe2+, Mg2+, Mn2+) where three of eight Si-tetrahedra are inverted across the interlayer sharing an apical oxygen with similarly inverted tetrahedra from the adjacent layers. The arrangement of the regular, D, and inverted, R

Sharp microfaceting of (001)-oriented cerium dioxide thin films and the effect of annealing on surface morphology

Cerium dioxide, CeO2, is a chemically stable oxygen-ion-conducting material, which has been extensively used as an additive or support in oxidation catalysts. The fact that catalytic behaviour is often surface structure sensitive and/or edge atom dependent suggests that different surfaces might be discernible in associated redox processes. Thus, it is desirable to realise CeO2 films with a well-de