86 research outputs found

    Room temperature InGaAs/InP distributed feedback laser directly grown on silicon

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    We report an optically pumped room-temperature O-band DFB laser, based on the buffer-less epitaxial growth of high quality InGaAs/InP waveguides directly on silicon wafer

    Trap-assisted tunnelling and Shockley-Read-Hall lifetime of extended defects in In.53Ga.47As p+n junction

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    Several In.53Ga.47As p+n junctions with various extended defect densities (EDDs) have been grown by metalorganic vapor phase epitaxy (MOVPE), by carefully controlling the growth conditions. After fabrication, T-dependent J-V, C-V and double DLTS (DDLTS) are performed to extract the electrical field dependence of the extended defect levels. From this characterization, it is derived that the extended defects dominate the electrical field enhancement factor Gamma regardless of the value of the EDD and significantly increases the leakage current under reverse bias (i.e., decrease the Shockley-Read-Hall lifetime). These impacts are strongly connected to a "band-like" density of states of extended defects E2 at E-C-0.32 eV by comparing the DDLTS and T-dependent J-V characteristics. On the other hand, the reference sample (without EDs) surprisingly exhibits an even stronger field dependence with lower leakage current. Nevertheless, no straightforward candidate point defects can be found in this sample and the possible explanation are discussed

    III-V on-silicon sources for optical interconnect applications

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    Optical interconnects require efficient and flexible optical sources. This paper presents results on two technology platforms being developed for realizing these. Integration using wafer bonding technologies is well established now and the focus is on new device types including tunable lasers, multi-wavelength lasers and switching. As an alternative, we also started work on monolithic integration using heteroepitaxy directly on silicon. We here report recent results on low threshold nanowire lasers

    III-V on silicon DFB laser arrays

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    We will present our work on epitaxially grown III-V on silicon DFB laser arrays, including results of pure InP-based lasers emitting around 900nm and InGaAs-on-InP lasers emitting around 1300nm

    Gender, migration and the ambiguous enterprise of professionalizing domestic service: the case of vocational training for the unemployed in France

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    Drawing on ethnographic data concerning migrant male domestic workers, this article examines the gendered dimensions of the process of racialization in Italy and France. First, it shows that specific racialized constructions of masculinity are mobilized by the employers as well as by training and recruitment agencies. These constructions of masculinity are related to different forms of organization of the sector in each country and to different ideologies about the integration of migrants. Second, the data presented reveal the strategies used by migrant male domestic workers to reaffirm their masculinity in a traditionally feminized sector. In doing so, this article intends to explore the connections between international migration and the gendering of occupations, with regard to the construction and management of masculinities in domestic service. Finally, by examining men’s experiences, this article aims to contribute to a more complex definition of the international division of care work

    Restauration morpho-dynamique et redynamisation de la section court-circuitée du Rhin en aval du barrage de Kembs (projet INTERREG / EDF)

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    National audienceThe Upper Rhine River has been heavily impacted by channelization for flood protection and navigation, and then by damming for hydropower generation. In normal non flooding conditions, most of the flows are diverted in a canalized section whereas the regulated “old Rhine” bypassed reach runs a minimum flow. Between Huningue and Neuf-Brisach, engineering works induced simplification and stabilization of the channel pattern from a formerly braiding sector to a single incised channel, hydrological modifications, bottom armouring due to bedload decrease, and thus ecological alterations. Two complementary and interdisciplinary projects have been initiated to restore alluvial morphodynamics: i) the international “INTERREG IV - Redynamisation of the old Rhine” project (2009-2012) coordinated by the Alsace region, France; ii) the left bank “controlled erosion” project launched by Electricité de France (EDF) within Kembs hydroelectric station relicensing process since 2003-2004. The purpose of these projects is to evaluate the feasibility of an important hydro-morphological and ecological restoration plan on a 45 km long reach, through both field testing of bank erosion techniques at favourable locations, and artificial sediments input from right bank excavations. This will help define possible long term prospective scenarios, in order to restore sustainable sediment transport, morphodynamics variability and associated ecological functions. The study will involve historical analysis, hydro-morphological / hydraulic physical and numerical modelling, physical and ecological monitoring, and sociological aspectsLe Rhin alsacien-allemand a enregistré de profondes modifications morphologiques et hydrologiques à la suite de sa correction et de sa régularisation pour la protection contre les crues et la navigation, puis après la construction de barrages hydro-électriques. Les aménagements réalisés entre Huningue et Neuf-Brisach ont engendré une simplification et une stabilisation du style fluvial. Un fleuve en tresses a cédé la place à un chenal unique incisé. Le fond de chenal est devenu pavé à cause d’une diminution des apports de charge de fond et des altérations écologiques ont été observées (simplification des habitats aquatiques et riverains). Deux projets complémentaires et interdisciplinaires ont été engagés afin de restaurer une dynamique des formes alluviales : i) le projet international INTERREG IV – Redynamisation du Vieux Rhin (2009-2012) sous l’impulsion de la région Alsace ; ii) le projet d’érosion maitrisée des berges de la rive gauche conduit par Electricité de France (EDF) dans le cadre du renouvellement de la concession de l’aménagement de Kembs. L’objectif des deux projets est de définir un plan de restauration hydro-morphologique et écologique conduisant à la redynamisation d’un tronçon de 45 km. L’étude repose sur une analyse historique, l’exploitation de modèles à la fois physiques et numériques, et les suivis morphologiques in situ d’une recharge artificielle en sédiments et d’érosions de berge contrôlées. Ces études de faisabilité sont complétées par des analyses écologique et sociologique pour apprécier l’impact socio-environnemental de ces projets
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