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ZnO and ZnO:Sb films were deposited using low pressure metal organic chemical vapor deposition on C- and R-oriented sapphire and O-polar ZnO substrates. Surface morphologies were studied using scanning electron microscopy. Whereas ZnO films grown on C-sapphire show a rough surface and hexagonal rods, the doped ZnO:Sb layers exhibit a relatively smoother surface, indicating a possible surfactant effect of antimony. The secondary ion mass spectrometry measurements permit to determine the antimony profile in the doped layers. Sb concentrations from 10 18 to 10 20 at/cm 3 were measured, depending on the growth conditions and substrate nature. Photoluminescence spectra exhibit donor-acceptor pair emission at 3.22 eV.

Until now, phosphorus is the best substitutional dopant for n-type diamond. Its incorporation is usually achieved using phosphine gas. However, organic precursors of phosphorus have been recently investigated. Among them, tertiarybutylphosphine (TBP) appears as an alternative to phosphine. In this report, we investigate the n-type doping of diamond with liquid TBP using the metal-organic chemical vapour deposition (MOCVD) technology for dopant incorporation. Our first results with liquid TBP precursor are compared with the results published for gaseous organic precursors of phosphorus.

The silicon incorporation in diamond is an important issue as silicon is widely used as a substrate for the growth of polycrystalline thin films. Incorporated silicon impurities are suspected to come from the hydrogen etching of the silicon substrate. To clearly establish this point we introduced a solid source of silicon during the growth of a homoepitaxial diamond layer on a HPHT diamond substrate. A quantitative SIMS analysis revealed concentrations of silicon up to 3 x 101 9 cm -3 in the diamond layer. Then we propose a scenario for the contamination of polycrystalline diamond grown on silicon substrates: after nucleation, the progressive paving of the silicon surface by 3D grains causes a fast decrease of its incorporation. At coalescence, the silicon substrate is completely covered by a 2D diamond film and the silicon concentration in diamond reaches a residual level. The investigated MPCVD and HFCVD diamond layers grown on silicon substrates present comparable features.

The concentration of radiative silicon centres in polycrystalline diamond films grown on silicon wafers was tentatively measured by their laser-induced luminescence (PL) at 1.681 eV. The total area under the PL line at room temperature is proportional to the amount of radiative Si point-defects in the volume excited by the laser beam. This amount was normalized to the area (expressed with the same arbitrary unit) under the diamond Raman line at 1332 cm -1 obtained simultaneously on the same set-up and compared to the absolute concentration determined by SIMS experiments. A linear relationship was obtained between the normalized PL area and the averaged SIMS values. Room temperature slope values (α laser ) of the linear relationship were obtained for the following laser lines: 632.8 nm, α 633 = 7.8 E + 15, 514.5 nm, α 514 = 2.5 E + 16 and for 488 nm, α 488 = 5.5 E + 16 at/cm 3 . SIMS profiles obtained in the different layers indicate that the distribution of silicon in the layers is a consequence of thermally activated diffusion from the silicon substrate during film growth.

Les pratiques de conduite du troupeau (femelles et produits) et de commercialisation des animaux ont été étudiées dans 21 élevages Charolais spécialisés en production de viande bovine. Il s’agissait de tester l’hypothèse selon laquelle certains éleveurs orientent leur système de production dans l’objectif de maximiser le nombre d’animaux vendus dans les filières qualité, par rapport à d’autres pour lesquels les priorités sont différentes (simplification de la conduite). Deux échantillons d’éleveurs ont été constitués selon ces deux catégories à partir d’enquêtes auprès de 4 groupements de producteurs. Trois types de résultats ressortent de l’étude: 1) les groupements ont discriminé les deux échantillons d’abord en fonction des effectifs et de la proportion d’a nimaux transitant effectivement par eux, et non en fonction du nombre d’animaux vendus dans les filières qualité , 2) le nombre d’animaux vendus dans les filières qualité ne suffit pas à rendre compte de la capacité des éleveurs à produire des animaux conformes aux cahiers des charges de ces filières, une grande partie de ceux-ci pouvant être valorisés autrement (notamment via des bouchers), 3) les éleveurs les plus impliqués dans les filières qualité n’ont pas forcément adopté des pratiques spécifiques, notamment une gestion plus minutieuse, plus ’à l’individu’ que les autres. Par contre, ils délèguent beaucoup plus la fonction de commercialisation à la structure d’aval, quitte à une moindre valorisation de chaque animal pris individuellement. Une autre classification des éleveurs combinant à la fois les pratiques et l’implication dans les filières qualité est alors proposée et discutée, plus complexe que celle correspondant à l’hypothèse de départ (5 groupes distincts).

Summary: Strontium ranelate appears to influence more than alendronate distal tibia bone microstructure as assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT), and biomechanically relevant parameters as assessed by micro-finite element analysis (μFEA), over 2years, in postmenopausal osteoporotic women. Introduction: Bone microstructure changes are a target in osteoporosis treatment to increase bone strength and reduce fracture risk. Methods: Using HR-pQCT, we investigated the effects on distal tibia and radius microstructure of strontium ranelate (SrRan; 2g/day) or alendronate (70mg/week) for 2years in postmenopausal osteoporotic women. This exploratory randomized, double-blind trial evaluated HR-pQCT and FEA parameters, areal bone mineral density (BMD), and bone turnover markers. Results: In the intention-to-treat population (n = 83, age: 64 ± 8years; lumbar T-score: −2.8 ± 0.8 [DXA]), distal tibia Cortical Thickness (CTh) and Density (DCort), and cancellous BV/TV increased by 6.3%, 1.4%, and 2.5%, respectively (all P

International audience; Heteroepitaxial growths of Zn1−xCdxO films were performed on R-oriented sapphire substrates by metal-organic chemical-vapor deposition. The authors carried out secondary ion mass spectrometry analysis, scanning electron microscopy, photoluminescence, and ellipsometric measurements to investigate the incorporation of cadmium in the layers, as well as its influence on the optical properties. Compositions up to 5.5% Cd were obtained, tuning the photoluminescence emission from 3.36 (ZnO) to 3.1 eV and increasing the refractive index at 600 nm from 1.94 to 2.

Although old generations of scleral contact lenses were totally replaced by soft and hard contact lenses, new designs and materials have recently allowed the successful use of nonfenestrated scleral contact lenses in patients who are intolerant to regular contact lenses. These new scleral contact lenses form a bridge over the cornea, which is thus permanently bathed in a saline reservoir.Retrospective study in patients suffering from corneal diseases altering the vision and/or responsible for ocular discomfort, and who are intolerant to conventional contact lenses.Fifteen eyes (10 patients) were fitted with specially designed scleral contact lenses. The mean follow-up was 16 months (range, 1-31 months). The scleral lenses were indicated for optical and/or therapeutic reasons: keratoconus (3 eyes), corneal grafts (7 eyes), refractive surgery (2 eyes), corneal dysplasia (2 eyes), and Stevens-Johnson syndrome (1 eye). Optical results and tolerance were excellent except for one eye.New nonfenestrated scleral contact lenses provide a good alternative for patients who are intolerant to conventional contact lenses.

Hydrogen (deuterium used as tracer) diffusion experiments were performed on undoped and boron doped diamond films ([B] = 1019and 1020 cm−3) grown by plasma CVD or hot-filament assisted CVD. The samples were exposed either to a radiofrequency plasma or a microwave plasma at different temperatures between 400°C and 900°C. The deuterium profiles were analysed by secondary ion mass spectrometry (SIMS). The deuterium diffusion was explained mainly in term of trapping on intergranular defects. The passivation of boron acceptors, by B-D complex formation in the deuterium diffused superficial layers of the diamond films, was followed by electrochemical and mercury probe capacitance measurements. The results suggest a strong decrease of the free carrier density, which is in accordance with passivation of free carriers by deuterium trapping on dopant.

The authors report the cases of two patients suffering of a rare long-term complication of contact lens wearing. Both patients wore daily soft contact lens for 5 and 8 years respectively. They presented with bilateral central predescemetic avascular haze associated with mild corneal stromal edema, descemetic folds in one patient and polymegethism on endothelial specular microscopic examination. The vision impairment was severe, unilateral in one patient and bilateral in the other. More than one year after removal of the contact lenses, only one patient fully recovered her initial visual acuity. The mechanisms of the onset of this corneal pseudo-dystrophy are discussed. Hypoxia and acidosis of the cornea induced by the contact lens are most probably responsible for this complication through endothelial metabolic dysfunction.

Nitrogen-doped ZnO films were grown by metal organic chemical vapor deposition using diallylamine as the doping source. Secondary ion mass spectrometry measurements attest for the incorporation of nitrogen up to 1020cm−3, and both photoluminescence and Raman characterization exhibit nitrogen related peaks. As-deposited layers have been characterized by Hall effect, and most exhibit n-type conductivity, with electron concentrations from 1017 up to a few 1019cm−3. Unstable p-type behavior is sometimes observed on low quality layers grown using a very low RVI∕II ratio. Ex situ annealing experiments in oxygen atmosphere show different tendencies depending on the growth conditions and can lead to a strong decrease in the electron concentration by three orders of magnitude. These results are discussed in relation to the structural and optical characterizations.

Homoepitaxial growths of ZnO were performed by low pressure metal organic chemical vapor deposition (MOCVD) on both bulk hydrothermal and thin film buffer layers of ZnO grown by pulsed laser deposition on c-sapphire substrates. The surface roughness, photoluminescence, and x-ray diffraction (0002) peak omega rocking-curve line widths for the bulk and thin film substrates were similar prior to MOCVD growth. After MOCVD growth, it was found that the surface morphology, crystallographic quality, and optical properties of the ZnO layers were far superior to those typically observed for heteroepitaxial growth of ZnO layers on c-sapphire by MOCVD. The MOCVD layers were comparable for growths on both the bulk substrate and the thin film buffer layer. Furthermore, no significant impact of carrier gas was observed. The quality of the ZnO layer appeared to be correlated with the surface morphology and the crystalline quality of the substrate rather than being dependent on whether the substrate was in bulk or thin f...

The fabrication of emitters may improve the quality of the base of a solar cell by a gettering process; this has been studied, using LBIC measurements, for three different phosphorous sources. The ability of these emitters to be passivated depends on their surface doping concentration; it has been possible to improve it by using etched-back emitters and also selective emitters where only the regions under the grid contact have a high doping level.