ZnSe growth on lattice-matched InxGa1-xAs substrates

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We have synthesized Si Nps rich submicron area within a thin SiO2 layer using a new method called “stencil-masked ion implantation”. It consists in implanting silicon ions at ultra-low energy through windows (from 50nm to 2μm) opened in a stencil mask containing. After thermal annealing the implanted regions perfectly mimic the mask geometry. Energy-filtered transmission electron microscopy images and PL measurement reveal that smaller nanocrystals are formed near the edges of the implanted areas due to a d

The synthesis, solution and solid state self-assembly properties of a series of polyisoprene-b-poly(ε-benzyloxycarbonyl-L-lysine) PI-b-PZLys and polyisoprene-b-poly(L-lysine) PI-b-PLys block copolymers have been examined. The formation of stimuli-responsive micelles in water has been studied as a function of pH and ionic strength using static and dynamic light scattering, UV-circular dichroism and transmission electron microscopy. The observed change in the micelles dimensions has been directly attributed t

Single crystal copper was irradiated with 590 MeV protons to a dose of 0.01 dpa at room temperature. Irradiated and unirradiated tensile samples were deformed and relaxation tests were performed at temperatures between 77 and 293 K. The tests show a strong temperature dependence of the flow stress of irradiated samples as compared to the unirradiated case. Deformed microstructures in the unirradiated and irradiated samples were investigated by transmission electron microscopy. The plastic deformation mechan

When AxGa1-xAs layers are grown on V-grooved GaAs substrates by metal organic chemical vapour deposition (MOCVD), a Ga rich vertical quantum well (VQW) appears in the V-groove centre. The width and Ga enrichment of this structure depend on the nominal Al concentration and growth temperature. From EELS linescans and spectrum images, concentration profiles and maps of VQWs are obtained, and a subsequent bandstructure calculation shows up to three confined sublevels in the VQW. Carrier confinement in segments

Spatially resolved photoluminescence spectra of thin GaAs quantum wells are measured by near-field spectroscopy, and two-energy autocorrelation functions of the spectra are derived. We demonstrate distinctly different autocorrelation functions for a 3-nm-thick quantum well grown on a (311)A surface and for quantum wells grown on (100) substrates. The autocorrelation spectra of the (311)A GaAs quantum well are quantitatively described by a statistical disorder model with a single correlation length of 17 nm

A transmission electron microscopy (TEM) study using weak-beam imaging has been addressed in order to assess the microstructure of NiAl (100) single-crystals subsequently to irradiation at room temperature with 700 keV nickel ions up to 10(15) cm(-2) or 1.5 dpa, namely, defect cluster formation and respective depth distribution. This work shows that the incoming ions undergo channeling along the [100] crystallographic direction and that the actual projected range is approximately 500 nm instead of the 250 n

Innovative structured catalysts based on nanoparticles of gold supported on activated carbon fibers (ACF) in the form of woven fabrics are presented for low-temperature CO oxidation. Gold was deposited by adsorption from aqueous solution of ethylenediamine complex [Au(en)2]Cl3 followed by reduction in hydrogen. The catalysts were studied under transient reaction conditions and characterized by high-resolution transmission electron microscopy (HRTEM) and X-ray energy dispersive analysis (EDS). HRTEM-EDS show

Relaxor Pb(Sc1/2Nb1/2)O-3 (PSN) thin films without pyrochlore phase were processed from the modified alkoxide solution precursors. The preparation of single phase PSN thin films has a narrow processing window due to the appearance of an undesirable pyrochlore phase and volatility of PbO. Thin film processing has been improved through selection of precursor solutions, heat treatment and optimized deposition-condition are optimized. Especially, the effects of Pt substrates seeded with additional layers upper

Using time-resolved photoluminescence, we have investigated the radiative behavior of neutral and negatively charged excitons in CdTe-based quantum wells. We find that the photoluminescence of negatively charged excitons can be well reproduced by a model of delocalized and thermalized three-particle complexes. A large radiative zone in k-space results from the transfer of the charged exciton momentum to the remaining electron (recoil effect). On the other hand, the photoluminescence decay of excitons is not

Nickel-aluminium intermetallics constitute interesting systems for the study of irradiation-induced phase transformations (order → disorder, amorphization) and production of defects. Irradiation of ordered intermetallics may induce disorder or amorphization depending on the projectile characteristics, irradiation conditions and chemical and physical properties of the target. The behavior of the various intermetallic compounds of the nickel-aluminium system with respect to electron and ion irradiation has be

In YBa2Cu3O6+x the tetragonal to orthorhombic transition occurs around x equals 0.3, followed by a continuum variation of lattice parameters. Hence both, the structural and superconducting properties, depend upon the oxygen content in CuO chains. Conversely, the epitaxial stress, exerted by the substrate on YBCO films, modified the lattice parameters, influencing the oxygen stability in the chains. The understanding of this mechanism is essential when growing epitaxial films for in-situ photoemission studie

Electrode stability, interdiffusion, phase purity and deviation from stoichiometry at the PZT-electrode interface are key issues in PZT thin film integration. This article highlights the use of transmission electron imaging combined with energy dispersive spectroscopy (EDS) for the investigation of these phenomena. The accuracy of the EDS analysis is discussed. It will be shown that using a standard PZT sample and controlled conditions, reliable analysis can be performed. Diffusion mechanisms have been stud

ZnSe growth on lattice-matched InxGa1-xAs substrates

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Controlled synthesis of silicon nanocrystals into a thin SiO2 layer synthesized by stencil-masked ultra-low energy ion implantation

Self-assembled nanostructures from peptide-synthetic hybrid block copolymers: Complex, stimuli-responsive rod-coil architectures

Tensile properties of irradiated Cu single crystals and their temperature dependence

Use of quantitative EELS and cathodoluminescence for study of carrier confinement and diffusion in self organized vertical quantum wells

Near-field autocorrelation spectroscopy of disordered semiconductor quantum wells

Channeling effects in heavy-ion irradiated NiAl(100) single-crystals: a TEM assessment in cross-section geometry using weak-beam imaging

Structured Au/FeOx/C catalysts for low temperature CO oxidation

Sol-gel derived Pb(Sc0.5Nb0.5)O-3 thin films: Processing and dielctric properties

Negatively charged excitons in CdTe-based quantum wells: A time-resolved study

The order-disorder transformation and microstructure evolution in nickel-aluminium intermetallics after heavy-ion irradiation

Structural properties of strained YBa2Cu3O6+x superconducting films grown by pulsed laser deposition

Stoichiometry and interdiffusion in PZT thin films studied by transmission electron microscopy