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Chủ đề: Học bổng và thảo luận về việc xin học bổng ngành vật lý

  1. #1
    svBK's Member Avatar của tungsin
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    Mặc định Học bổng và thảo luận về việc xin học bổng ngành vật lý

    mọi người có thông tin gì vào đây trao đổi nhé

  2. #2
    svBK's Member Avatar của tungsin
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    Mar 2007
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    57

    Mặc định

    Research field

    Solid state physics, surfaces and interfaces / Solid state physics, chemistry and nanosciences
    Physical chemistry and electrochemistry / Solid state physics, chemistry and nanosciences
    Title

    Grafted graphene for electronic nanocontacts
    Abstract

    This thesis project aims at studying the conductivity mechanisms within a nanocontact involving graphene sheets chemically anchored on various surfaces, in a junction metal/graphène/organic primer/metal. The electrical investigations will mainly be performed using original techniques deriving from the Atomic Force Microscope (AFM) thanks to the "Resiscope" module developed at Supelec/LGEP. That tool allows measuring local resistance among 11 orders of magnitude simultaneously with standard topology or friction analysis. That approach has already been validated very recently within a close collaboration between Supelec/LGEP and the Chemistry of Surfaces and Interfaces Lab at CEA Saclay (LCSI). The graphène sheets are anchored on the docking surfaces thanks to an organic ultrathin self-adhesive primer developed at CEA/LCSI. The junction will then be studied using a classical conducting tip, or using a microdot at the apex of the tip. Hence, model micro- and nano-contacts can be defined with good accuracy in terms of geometry and mechanics.

    The electrical characterization of the micro- or nano-junction will be performed through I(V) recording. The role of the covalent grafting between the organic primer layer and the graphène sheet on the final electrical properties of the junction will be evaluated, together with the influence of the pressure applied by the conducting AFM tip. Other parameters will also be studied, including conduction threshold effects connected to percolation phenomena (i.e. when the junction works as a molecular-sized switch without any contact opening).

    This project belongs clearly to the molecular electronics field, which intends to propose alternative solutions to the silicon-based microelectronics. Graphene is obviously a very promising material for that purpose

    Location

    Institut rayonnement et matière de Saclay
    Service de Physique et de Chimie des Surfaces et Interfaces
    Laboratoire de Chimie des Surfaces et Interfaces
    Centre : Saclay
    Starting date : 01/10/2010
    Contact person
    Pascal Viel
    CEA / DSM/IRAMIS/SPCSI/LCSI
    CEA Saclay

    DSM-IRAMIS-SPCSI

    Batiment 466 p10

    91 191 Gif sur yvette
    Phone : +33 169 084 147
    More about
    http://iramis.cea.fr/spcsi/Phocea/Pi...id=pascal.viel
    http://iramis.cea.fr/spcsi/
    University / Graduate School

    Paris XI
    Sciences et Technologies de l'Information, des Télécommunications et des Systèmes (STITS) - Paris XI -
    Thesis supervisor
    Sophie NOEL
    Supelec/LGEP / Contacts Electriques
    Laboratoire de Génie Électrique de Paris Plateau du Moulon

    11 rue Joliot Curie

  3. #3
    svBK's Member Avatar của tungsin
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    Mặc định

    Research field

    Electronics and microelectronics - Optoelectronics / Engineering science
    Solid state physics, surfaces and interfaces / Solid state physics, chemistry and nanosciences
    Title

    Carrier transport in Si nanowire MOSFETs
    Abstract

    Context of the work :

    The silicon nanowire MOSFETs (single wire or 3D stack) are a promising alternative to carry on the scaling and to further increase the integration density on chip, as well as the transistors performance. The surrounding gate and a diameter of only tenth of nanometers provide a better electrostatic control of the conduction channel, by reducing the short channel effects. These new architectures come along with the introduction of new materials (high permittivity oxide, metal gate ?) in order to optimize the electrical properties of the devices. The specificity of the nanowire FETS relies mainly on the surrounding gate and the 2D quantum confinement. The complexity of these structures (1D carrier transport, interface roughness, multiple crystallographic orientations), added to the impact of the gate materials (defects and charges due to the high-k oxide and nitrided gate), leads to a strong modification of the electronic properties as compared to standard planar architectures. The challenge is to achieve a better understanding of the device operation and to build physical models to describe it, in order to evaluate the potentialities and the performance of nanowire transistors.



    Objectives:

    The aim of the thesis is to study the transport properties of the nanowire (NWs) MOSFETs, in particular to understand the scattering mechanisms limiting the drain current in linear and in saturation regime.

    The work relies on electrical measurements ? to develop or to adapt to the specific NW MOSFETs archtitecture ?, and the extraction of fundamental parameters from the experimental data (equivalent oxide thickness, access resistance, inversion carrier density?). Advanced measurement techniques, such as pulsed drain current, low temperature measurements or magnetoresistance measurements, will help to achieve the more complete characterization as possible of the these innovative devices (mobility extraction, interface traps density in the gate oxide, ballisticity rate evaluation?). The originality of the work consists in the possibility of exploring the piezoresistivity properties of these devices, by studying the impact of a mechanical strain (applied by a four-point bending fixture for example) on the electronic properties. A special attention will be given to parameters like the carrier mobility or the mean free path in the channel, the access resistance, or the injection velocity, which are determinant in order to optimize the electrical performance.

    Analytical models will be built from experimental data, to describe the different physical effects evidenced in NW MOSFETS. The models will include the quantum effects inherent to the 2D confinement of these devices. Numerical transport simulations (like MONTE-CARLO,?) could be used to support the results and to deal with some scattering mechanisms such as the interface roughness scattering which plays an important role. These analytical models, based on physics, will provide the starting material for TCAD and compact modelling, needed for circuit simulation.

    Comparison with more simple fully-depleted silicon-on-insulator (FD-SOI) planar structures will bring physical mechanisms occurring in NW to light, such as the effect of the crystallographic orientation or the impact of the technological processes, and will also help to rate the performance of the NW FETs.



    The work will be done within the electrical characterization and simulation laboratory, in strong collaboration with the device integration team of CEA-Léti, and in collaboration with external simulation labs (CNRS). Solid knowledge in solid-state physics and in semiconductor physics is required.

    Location

    Département Nanotec (LETI)

    Laboratoire Simulation et Caractéristisation Electriques
    Centre : Grenoble
    Starting date : 01/10/2010
    Contact person
    Mikaël CASSÉ
    CEA / DRT/D2NT//LSCDP
    CEA-Léti - MINATEC

    LETI/D2NT/LSCE

    17, rue des Martyrs

    38054 Grenoble Cedex 9

    FRANCE


    Phone : +33 438 784 491
    University / Graduate School

    Aix-Marseille I
    Sciences pour l'Ingénieur : Mécanique, Physique, Micro et Nanoélectronique - Aix-Marseille I -
    Thesis supervisor
    Daniela MUNTEANU
    CNRS / IM2NP - UMR CNRS 6242
    IM2NP - UMR CNRS 6242

    Bâtiment IRPHE

    49, rue Joliot-Curie - BP 146

    13384 MARSEILLE Cedex 13

  4. #4
    svBK's Member Avatar của tungsin
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    Mặc định

    Research field

    Solid state physics, surfaces and interfaces / Solid state physics, chemistry and nanosciences
    Materials and applications / Engineering science
    Title

    Influence of alloying elements on properties of defects in ferritic steels
    Abstract

    Ferritic/martensitic steels are potential candidate materials for generation-IV fission reactor applications. Dispersion of nano size oxide particles of Y and Ti by mechanical alloying is one of the possible solutions adopted to improve the irradiation creep and void swelling problems. Additional minor alloying elements like W and Zr are also used to improve the mechanical properties of these structural steels. The main components of these nano-sized oxide particles are often introduced through ball milling, which induces a high concentration of solutes in the iron matrix forming solute-vacancy complexes. The nano-cluster formation occur during subsequent high temperature and high pressure processing (hot isostatic processing ? HIP) However, significant amount of solutes may stay in the solid solution during and after such heating process. At fundamental research level, stability and migration of the solute atoms like Y, Ti, Zr and W along with O in the presence of supersaturated vacancies in alpha-Fe need to be understood in detail by combining controlled experiments and multiscale modeling.

    On the experimental side, binary alloys FeX, (X = Y, Ti, Zr, W, O) of various compositions will be prepared and characterized. Point defects will be introduced by various means like plastic deformation, quenching, electron irradiation and ion beam irradiation. Defect evolution will be studied using electrical resistivity, positron annihilation. Energetics of vacancy-solute complexes such as effective formation and migration energies of solute-vacancy complexes will be experimentally deduced.

    In parallel, multiscale modeling will be developed to interpret the experimental observations. Ab initio calculations within Density Functional Theory (DFT) allow us to understand and quantitatively estimate solute-vacancy and solute-solute interactions. Also, the stability and mobility of solute-vacancy complexes can be studied by coupling first principles and Kinetic Monte Carlo or Rate Theory simulations. In addition, positron annihilation parameters such as positron lifetimes will be computed using DFT results, which will allow a direct comparison with experimental data.



    This thesis is within a French-Indian collaboration framework, which may consist in a larger modeling part complemented with experimental activities or vice versa, depending on interest and profile of the candidate.

    Location

    Département des Matériaux pour le Nucléaire
    Service de Recherches Métallurgiques Physiques
    Service de Recherches de Métallurgie Physique
    Centre : Saclay
    Starting date : 01/10/2010
    Contact person
    Chu Chun FU
    CEA /
    CEA/Saclay, Bat. 520, piece 116
    Phone :
    University / Graduate School

    Paris VI
    Thesis supervisor

  5. #5
    svBK's Member Avatar của tungsin
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    Mặc định

    Research field

    Solid state physics, surfaces and interfaces / Solid state physics, chemistry and nanosciences
    Materials and applications / Engineering science
    Title

    Silicon dioxide direct bonding : basic mechanisms
    Abstract

    For more than fifteen years, CEA-LETI is involved in the development and the use of direct bonding processes of silicon oxides with diverse surface preparations. We notice that the bonding results vary strongly according to the oxides realization modes or according to the bonding processes. Today, the associated mechanisms are not regrettably enough understood. The problem is all the more sensitive as new structures constituted by diverse materials are piled more and more often thanks to the direct bonding and thanks to the use of silicon oxide layers, which can be deposited on these new materials to facilitate bonding. It appears clearly the need to understand the mechanisms of involved direct bonding in particular by taking into account the characteristics of these oxides and the constraints connected to these new structures.

    The objective of this study is to establish the physical and chemical mechanisms involved during processes of direct bonding. Diverse natures of silicon oxides (SiO2), connected to their elaboration, will be studied. Bonding will be performed with surfaces of the same nature or different natures. The direct bonding processes differing by the surface preparation or the surface cleaning techniques, the atmospheres of bonding (atmospheric or under vacuum), the heat treatments used before andor after the bonding, the sizes to be bonded and the surface topology will be analyzed. Applications implying heterostructure bonding for microelectronics or microtechnologies, 3D integration, sensors, biotechnologies, photovoltaic? will be looked for.

    Location

    Département Nanotec (LETI)

    Laboratoire de Transfert de films et Circuits
    Centre : Grenoble
    Starting date : 01/09/2010
    Contact person
    Hubert MORICEAU
    CEA / DRT/D2NT//LTFC
    CEA/Grenoble
    Phone : +33 438 784 823
    University / Graduate School

    Grenoble INP
    IMEP2: Ingénierie - Matériaux - Environnement - Energétique - Procédés - Production - Grenoble INP
    Thesis supervisor
    François RIEUTORD
    CEA / DSM/INAC
    CEA/Grenoble

    17 rue des Martyrs

    38054 GRENOBLE

  6. #6
    svBK's Member Avatar của tungsin
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    57

    Mặc định

    Research field

    Materials and applications / Engineering science
    Solid state physics, surfaces and interfaces / Solid state physics, chemistry and nanosciences
    Title

    Study of the degradation mechanisms of the electrode nanomaterials used in lithium batteries.
    Abstract

    Lithium batteries are now a strategic issue for car industry. The development of nanomaterials and the control of the chemistry at nanometer scale have lead to a dramatic improvement of the capabilities. However, one of the main problems for the use of high performances materials is their low cyclability due to damaging mechanisms. The thesis will be devoted to the understanding of such mechanisms by using advanced characterization equipments such as transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and nano-Auger imaging. The Ph.D student will work at CEA-Grenoble in the laboratory of energy components for the elaboration of the electrode nanomaterials and for electrical measurements, and in the nanocharacterization platform of Minatec for the fine microstructural observations. The thesis will lead the understanding of the different types of degradation mechanisms and, in some cases, to proposals of optimised materials.
    Location

    Département de l'Electricité et de l'Hydrogène pour les Transports (LITEN)

    Laboratoire des Composants PEM
    Centre : Grenoble
    Starting date : 01/10/2010
    Contact person
    Cyril CAYRON
    CEA / DRT/DTH
    CEA/Grenoble
    Phone : +33 438 789 329
    More about
    http://www-liten.cea.fr/index.htm
    University / Graduate School

    Grenoble I
    Ecole Doctorale de Physique de Grenoble - Grenoble I -
    Thesis supervisor
    Pascale BAYLE-GUILLEMAUD
    CEA / DSM/INAC
    CEA/Grenoble

    17, rue des Martyrs

    38054 Grenoble cedex 9

  7. #7
    svBK's Member Avatar của tungsin
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    Mar 2007
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    57

    Mặc định

    Research field

    Radiation-matter interactions / Solid state physics, chemistry and nanosciences
    Solid state physics, surfaces and interfaces / Solid state physics, chemistry and nanosciences
    Title

    Modeling, Elaboration and Characterization of Diffractive Gratings for Light Trapping Optimization in Solar Cells
    Abstract

    Location

    Département des Technologies des NanoMatériaux (LITEN)

    Laboratoire Technologies des Surfaces
    Centre : Grenoble
    Starting date : 01/10/2010
    Contact person
    Alexandre PEREIRA
    CEA / DRT/DTNM//LTS
    17 rue des Martyrs

    Bât 4005 P. 5217

    38054 Grenoble
    Phone : +33 438 782 977
    University / Graduate School

    Grenoble INP
    Electronique, Electrotechnique, Automatique, Traitement du Signal (EEATS) - INP Grenoble -

  8. #8
    svBK's Member Avatar của tungsin
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    Mar 2007
    Bài gửi
    57

    Mặc định

    Research field

    Solid state physics, surfaces and interfaces / Solid state physics, chemistry and nanosciences
    Materials and applications / Engineering science
    Title

    Spin polarized current induced Domain Wall motion
    Abstract

    Location

    Institut nanosciences et cryogénie
    Spintronique et technologie des composants
    Laboratoire Spintec
    Centre : Grenoble
    Starting date : 01/10/2010
    Contact person
    Gilles GAUDIN
    CNRS / INAC/SPINTEC
    Bât 1005, CEA Grenoble
    Phone : +33 438 782 384
    University / Graduate School

    Grenoble I
    Ecole Doctorale de Physique de Grenoble - Grenoble I -
    Thesis supervisor
    Alain SCHUHL
    UJF / SPINTEC/Laboratoire Spintec
    Spintec (URA 2512 CEA/CNRS)

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