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Discusses Lorentz microscopy and its application to the study of laser-written domains in amorphous rare-earth/transition-metal-type materials. Conditions needed to obtain good quality images; Discussion on Lorentz imaging with magneto-optical films; Example of correlation between the field dependence of the microstructure and measurements of magneto-optical signal.

Résumé Objectifs de l’étude Le traitement conservateur des carcinomes canalaires in situ du sein repose sur la tumorectomie suivie d’une irradiation mammaire. L’impact d’un complément d’irradiation au niveau du lit opératoire est en cours d’évaluation. Patientes et méthodes Étude rétrospective d’une cohorte monocentrique incluant l’ensemble des patientes atteintes d’un carcinome canalaire in situ traité par tumorectomie suivie de radiothérapie externe de 45 Gy et complément de 15 Gy entre 1990 et 2008. Résultats Cent soixante et onze patientes ont été incluses. Le suivi médian était de 95,1 mois. Le complément d’irradiation du lit opératoire a été administré par une technique de curiethérapie interstitielle pour 66 patientes (39 %), par un faisceau direct d’électrons pour 86 (50 %) et par des faisceaux tangentiels de photons pour 19 (11 %). Huit rechutes locales (4,6 %) ont été observées. Le taux de survie sans rechute locale était de 97 % à 10 ans. Le taux de survie globale à 10 ans était de 98 %. Après analyse multifactorielle, la curiethérapie ( p = 0,05 ; hazard ratio = 5,15 ; intervalle de confiance = 1–26,3) était un facteur significatif de réduction du taux de survie sans rechute locale. Conclusion Dans notre expérience, l’irradiation mammaire suivie d’un complément dans le lit opératoire a permis d’obtenir un taux de survie sans rechute locale à 10 ans élevé. Purpose Women with ductal carcinoma in situ are treated with breast-conserving surgery and radiation therapy. The impact of an additive boost radiation is under evaluation. Patients and methods All women treated for ductal carcinoma in situ with breast-conserving surgery and whole breast radiation therapy at a total dose of 45 Gy with a boost radiation from 1990 to 2008 have been included in this retrospective monocentric retrospective study. Results We included 171 patients. Boost radiation to the surgical bed was delivered by brachytherapy in 66 patients (39%), by direct en-face electron beam in 86 patients (50%), and by tangential fields using photon beams in 19 patients (11%). Median follow-up was 95.1 months. Eight local relapses (4.6%) have occurred. The 10-year local recurrence-free survival rate was 97%. The 10-year overall survival rate was 98%. On multivariable analysis, brachytherapy ( P = 0.05; HR = 5.15; IC = 1–26.3) was associated with a reduction risk of local recurrence-free survival. Conclusion In our experience, women treated for a ductal carcinoma in situ with breast-conserving surgery and whole breast radiation therapy with a boost radiation have a high 10-year local recurrence-free survival rate. [ABSTRACT FROM AUTHOR]

Catalyst-free GaN nanowires with InGaN quantum disks (QDs) were characterized by scanning/transmission electron microscopy (S/TEM) and photoluminescence. A variety of structures, from QDs with large strain fields to apparently strain free QDs were observed. TEM lattice imaging revealed dislocations in the QD regions of the samples. Stacking faults were also observed and appear to be associated with the GaN growth temperature rather than the presence of indium. Energy dispersive X-ray spectroscopy in the TEM revealed indium concentrated in stacking faults but not always localized in the QD regions. Photoluminescence spectra show a red-shift, possibly associated with indium concentration. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

We report on the light propagation in a one-line-defect photonic crystal waveguide (W1 PhC WG) patterned into a 450 nm thick free-standing lithium niobate membrane by ion-beam enhanced etching. The Bloch wave vectors and transmission spectrum of this PhC WG were retrieved from optical near-field images. The experimental data show good agreement with simulations performed with the three-dimensional (3D) finite-element method and the 3D finite-difference time-domain method. Those results are promising for the development of integrated optics devices operating at telecom wavelengths and based on free-standing lithium niobate PhC membranes. [ABSTRACT FROM AUTHOR]

High resolution images of laser-written magnetic domains in thin sputtered films of terbium iron have been obtained using Lorentz microscopy. The domains, written with a GaAs diode laser, are generally circular in shape with diameters in the range 0.9–2.2 μm. Conditions necessary for the observation of highly detailed images are described. It was found that with certain values of laser power and applied magnetic field, smaller irregular domains appear within the principal domains. [ABSTRACT FROM AUTHOR]

Presents the detailed micromagnetics of magnetization reversal in amorphous terbium-iron films by Lorentz microscopy. Nucleation and growth behavior of reverse domains; Method used to avoid the formation of oxidized surface layers; Types of magnetization reversal behavior.

This paper presents two new experimental observations on electrodeposited copper: unusual morphology as seen in the scanning electron microscope at high magnification, and mechanical properties, as measured by tensile testing. We report detailed characterization of a 2.6 μm thick copper electrodeposit, made on silicon using laboratory procedures and similar to materials now widely used in advanced electronic interconnect structures. The microstructure was characterized by X-ray diffraction, electron backscattered diffraction, imaging in a field emission scanning electron microscope (FESEM), and microtensile testing. Initial observations indicated microstructural dimensions and mechanical properties in the expected ranges. However, using high-magnification, high resolution imaging in the FESEM, we found a surprising result: the morphology of this electrodeposit resembled an agglomeration of round balls or spheres approximately 30–50 nm in diameter. Both X-ray and electron diffraction results showed grain and subgrain sizes much larger than the individual spheres. Molecular dynamics (MD) simulations of spheres of copper atoms were carried out to interpret the observations, and produced a degree of interpenetration of the spheres that was consistent with the observations. However, in MD simulations of two initially misoriented spheres of up to a thousand atoms, with diameters up to 3 nm and for durations up to 30 ps, the spheres readily agglomerated but remained misoriented. So, the mechanism and rate of crystallographic grain growth within the agglomeration of spheroids remains unknown. This unusual spheroidal morphology may be related to the unusual room-temperature grain growth observed in electrodeposited copper. [Copyright &y& Elsevier]

We experimentally investigated the role of background signal in time resolved photoluminescence experiments with single quantum dots on substrates. We show that the background fluorescence signal from thin gold films fabricated by electron-beam evaporation and from AlO layers fabricated by atomic layer deposition have to be taken into consideration in experiments on the single photon level. Though all investigated components can be distinguished by their photoluminescence decay rates, the presence of the background signal prevents the observation of photon antibunching from single quantum dots. Moreover, a single quantum dot acts as a hot spot enabling the plasmon supported fluorescence enhancement of gold. [ABSTRACT FROM AUTHOR]

Brillouin-light-scattering measurements and finite-element modeling of vibrational spectra in the range of 5–40 GHz are presented for an array of monocrystalline GaN nanowires with hexagonal cross sections. Analysis of the spectra is substantially complicated by the presence of a distribution of nanowire diameters. The measurements and calculations reveal a variety of modes with simple flexural, higher-order flexural, approximately ‘plane-strain’, approximately longitudinal and torsional displacement patterns that are similar to the corresponding modes of isotropic cylinders. The largest peaks in the spectra with acoustic angular wavenumbers in the range of 4 to ∼15 μm−1 were determined to arise from modes with relatively large transverse displacements, consistent with inelastic light scattering arising predominantly from surface ripple. These dominant modes have finite frequencies in the limit of zero wavenumber, corresponding to transverse standing waves. At higher wavenumbers, the spectra provide evidence for increased scattering through elasto-optic coupling, especially with respect to the emergence of a peak from a mode analogous to the longitudinal guided modes of thin films. [ABSTRACT FROM AUTHOR]

Electron scattering mechanisms in copper lines were investigated to understand the extendibility of copper interconnects when linewidth or thickness is less than the mean free path. Electron-beam lithography and a dual hard mask were used to produce interconnects with linewidths between 25 and 45 nm. Electron backscatter diffraction characterized grain structure. Temperature dependence of the line resistance determined resistivity, which was consistent with existing models for completely diffused surface scattering and line-edge roughness, with little contribution from grain boundary scattering. A simple analytical model was developed that describes resistivity from diffuse surface scattering and line-edge roughness. [ABSTRACT FROM AUTHOR]

Atomic layer deposition (ALD) can be used to deposit ultra-thin and conformal films on flat substrates, high aspect ratios structures and particles. In this paper, we demonstrate that insulating, multilayered and functionalized ALD coatings can also be deposited conformally on carbon nanotubes. Multilayered coatings consisting of alternating layers of dielectric and conductive materials, such as Al2O3 and W, respectively, are deposited on conductive multi-walled carbon nanotubes. This coated carbon nanotube can function as a nanoscale coaxial cable. Thin layers of Al2O3 ALD are also used as a seed layer to functionalize nanotubes. A carbon nanotube was made highly hydrophobic using an Al2O3 ALD seed layer followed by the attachment of perfluorinated molecules. [ABSTRACT FROM AUTHOR]

Spatially resolved photoluminescence properties of semi-insulating, liquid encapsulated Czochralski-grown GaAs substrates are analyzed with a laser scanning microscope. The improved resolution of the laser scanning microscope results in the observation of single dislocations within the subgrain boundaries of the polyganized dislocation cell network for the first time by photoluminescence. Both the cell structure and the Cottrell cloud are clearly resolved. [ABSTRACT FROM AUTHOR]