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We studied the optical properties of hybrid multilayer microspheres (HMMs). We prepared multilayer particles with alternating radial layers of gold nanoparticles (NPs) and poly(methyl methacrylate) and achieved control over particle size, the thickness of particle layers, and the surface coverage of gold NPs. We showed the ability to tune the spectral characteristics of the HMMs, which was based on frequency dispersion of the dielectric constant of polymer-metal NP structures. Good agreement between experimental and theoretical extinction properties of the HMMs was obtained. In comparison with multilayer structures synthesized solely from polymers, hybrid multilayer microspheres have a larger refractive layer contrast between adjacent layers, which is important for practical applications in optoelectronic devices. Key words: hybrid polymer-inorganic materials, polymer microspheres, gold nanoparticles, optical properties, extinction spectra. On a etudie les proprietes optiques de microspheres multicouches hybrides (MMH). On a prepare les particules a multicouches comportant des couches radiales alternantes de nanoparticules (NP) d'or et de poly(methacrylate de methyle) et on a pu controler la taille des particules des couches et la surface de la couverture des nanoparticules d'or. On a pu controler les caracteristiques spectrales des microspheres multicouches hybrides en ajustant la frequence de dispersion de la constante de dielectrique des structures des nanoparticules polymere-metal. On a obtenu un bon accord entre les proprietes d'extinction experiinentales et theoriques des microspheres multicouches hybrides. Par comparaison avec les structures multicouches synthetisees uniquement a partir de polymeres, les microspheres multicouches hybrides possedent un plus grand contraste de refraction par couche entre les couches, propriete importante pour les applications pratiques dans les appareils optoelectroniques. Mots-cles : materiaux hybrides polymere-inorganique, microspheres de polymere, nanoparticules d'or, proprietes optiques, spectres d'extinction. [Traduit par la Redaction] doi: 10.1139/V09-172, Introduction Polymer microspheres with a multilayer onion-like structure possess optical properties that are useful in photonic crystals, (1-2) optical data storage, (3-4) biometrics, (5,6) and, sensing and single-particle optical limiting. [...]

The relation between the various morphologies and optical properties of ZnSe nanostructures is investigated. Photoluminescence (PL) measurements on crystalline nanowires have shown that the spectrum comprises two characteristic peaks corresponding to strong near band emission and a weaker emission associated with defect states, but the PL spectra of ZnSe nanoribbons containing a high density of structural defects are dominated by defect related emission.

Research describing inductively coupled plasma etching is presented. In particular Indium Phoshide (InP)-based nanostructures are investigated for etching techniques using N2/H2 plasmas.

A new study provides a model for coherent island formation in heteroepitaxial thin films.

The clustering of chlorine chemisorbed on gallium arsenide(001)-c(8x2) surfaces was observed using scanning tunneling microscopy.

A quantum model that uses N two-level atoms within a photonic band-gap material and interacting with a single photon mode under suitable nonequilibrium boundary conditions has been developed. The solution of the eigenvalue problem of the Hamiltonian shows that the total system behaves like any two-level system with the eigenvectors existing in a dual pair of spaces. The interaction of the atoms with the single photon mode does not result in decoherence over the constructed quantum logic gates.

A study was conducted on a specific class of neural network models called quantum cellular neural networks. It employed a subdynamics formula for complex dynamic systems to investigate the eigen value problem of the Hamiltonian for a two-dimensional Ising model coupled with a local external field, regardless of whether the system is or is not in equilibrium state. A Jordan-type spectral decomposition for the hamiltonian operator and the evolution formula of the density operator are presented.

A subdynamics-based general formulation was derived for the construction of the spectral decomposition of the Hamiltonian for N excitons limited by a quantum dot with parabolic potential and mediated by an electromagnetic field. Using the formulation, the spectrum of the Hamiltonian of N excitons can be computed based on recurrence relations for the operators of creation and destruction. Then the spectral decomposition of the Hamiltonian of the system can be constructed using the intermediate operator and the intertwining relation.

GaAs-based semiconductors are useful for fabricating low-power, high-speed, high-frequency semiconductor devices and integrated circuits. However their performance is degraded by surface and interface states, and various passivation approaches are being developed. The role of O on GaAs surfaces during Ga(sub2)O(sub3) passivation has been studied, with particular focus on GaAs(100) Ga-terminated surfaces. Results showed that a reduction in surface-state density comes from the initial near-bridge-bonded O atoms.

The development of lateral interaction force is responsible for the multitude of surface reconstruction for GaAs(III) surfaces. This mechanism is proposed by studying two H3Ga3Ag3H6 and H6Ga3Ag3H3 models. The lateral force increases Ga-As-Ga band angle and reduces As-Ga-As band angle. This mechanism explains the absence of one-quarter of Ga atoms from Ga-terminated (III)A surfaces and the absence of a third of As atoms in As-terminated (III)B surfaces.

The selective area growth of InAs quantum dots (QDs) on GaAs through 20 nm Si[O.sub.2] windows prepared by block copolymer lithography is described. Highly uniform array of InAs and GaAs QDs is obtained with mean diameters and areal densities.

The excitation power dependence of photoluminescence from ZnSe nanowires fabricated via the vapor-phase growth method under excess Zn conditions is reported. The results from luminescence spectra provide insight into excitonic emission, the binding energy of the exciton, and transition states of donor-acceptor pair.

The effect of nonstoichiometric growth conditions on the optical quality of single crystal zinc selenide (ZnSe) nanowires is reported. Results reveal that nanowires grown under Zn-rich conditions had a strong band edge (BE) emission, while nanowires grown under Se-rich conditions had a strong defect related emission.

The full details of the synthesis and characterization of highly metallized polyferrocenylsilanes (PFSs) with pendant cobalt, molybdenum, and nickel clusters through macromolecular complexation of carbon-carbon triple bonds in acetylide-substituted PFSs is reported. The studies suggest that the highly metallized polymers may be useful in the fabrication of patterned arrays of alloy nanoparticles for both materials science and catalytic applications.

Ferroelectric Ba0.7Sr0.3TiO3 films are fabricated using a PbO-doped barium strontium titanate sol-gel precursor. The findings show that doping in excess of 20 at. % PbO is found to markedly decrease film porosity, while enhancing crystallization by decreasing the annealing temperature required for the formation of the perovskite phase form above 650 degree C to 500 degree C.

A method for quantum control coherence in an open quantum computing system is presented to find a suitable control sequence for maintaining coherence in a silicon-based nuclear spin quantum computing system, subject to Bose-type environmental noise, and under the Born-Markovian and rotating wave approximations. It is demonstrated that the evolution operator remains decoherence free while the three control pulses are being applied.

Chemical reactions on surfaces are important in many areas of science and technology. On metal surfaces, the electronic states of the surface atoms are spatially extended and can therefore easily [...]

A model of a two-dimensional quantum cellular neural network (QCNN) was described. The eigenvalues and eigenvectors for the Hamiltonian of a neuron were obtained. It was confirmed that the ground or memory states were approximately two polarization states of 16 possible states in a neuron. It was shown that the local external magnetic field can drive the system to a global polarization state and induce a dynamical response in the original QCNN.