PhD subjects

29 sujets INAC

Dernière mise à jour : 19-06-2018


• Chemistry

• Electronics and microelectronics - Optoelectronics

• Materials and applications

• Mechanics, energetics, process engineering

• Mesoscopic physics

• Physical chemistry and electrochemistry

• Soft matter and complex fluids

• Solid state physics, surfaces and interfaces

• Theoretical Physics

• Thermal energy, combustion, flows

• Toxicology

• Ultra-divided matter, Physical sciences for materials

 

Synthesis and characterization of organic photochromic dyes for application in dye sensitized solar cells with variable optical transmission

SL-DRF-18-0523

Research field : Chemistry
Location :

SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé

Synthèse, Structure et Propriétés de Matériaux Fonctionnels

Grenoble

Contact :

Renaud DEMADRILLE

Starting date : 01-10-2018

Contact :

Renaud DEMADRILLE

CEA - DRF/INAC/SyMMES/STEP

04 38 78 44 84

Thesis supervisor :

Renaud DEMADRILLE

CEA - DRF/INAC/SyMMES/STEP

04 38 78 44 84

Personal web page : http://inac.cea.fr/Pisp/57/renaud.demadrille.html

Laboratory link : http://inac.cea.fr/Phocea/Vie_des_labos/Ast/ast_service.php?id_unit=1147

More : http://www.spram-solar.fr/

Among the emerging photovoltaic technologies, dye-sensitized solar cells (DSSC) show some of the required features for applications and future developments at the industrial level. The SyMMES laboratory has started to develop since 2012, new purely organic dyes for the replacement of ruthenium dyes in DSSCs. Some of these new molecules have shown high performances (above 10%) and outstanding stability (more than 5000h under continuous irradiation at 65°C) when combined to ionic-liquid based electrolytes.

In this thesis project we propose to develop a new class of organic sensitizers based on functional aromatic chromophores that will confer photochromic properties to the molecules.These molecules are expected to show reversible and tunable absorption in the visible range upon irradiation. The functional aromatic heterocycles will be developed in the first part of the project and incorporated in chemical structures of push-pull type organic dyes. Using this strategy we will develop sensitizers with variable absorption bands.

In order to develop more robust and efficient solar cells, ionic liquid electrolytes containing iodine-free redox systems will be developed. Our objective will be to obtain fully transparent and stable electrolytes to give rise to a new generation of robust and efficient dye-sensitized solar cells with variable optical transmission.

Using the research facilities of Hybrid-En and the equipment that is available in SyMMES the new molecules and electrolytes will be fully characterized (structural, electrochemical, optical properties), and they will be incorporated and tested in devices. Their photovoltaic performances and their stability will be evaluated.

System-level simulation and exploration flow for non-volatile neuromorphic architectures

SL-DRF-18-0278

Research field : Electronics and microelectronics - Optoelectronics
Location :

Spintronique et technologie des composants

Laboratoire Spintec

Grenoble

Contact :

François DUHEM

Benoît MIRAMOND

Starting date : 01-10-2018

Contact :

François DUHEM

CEA - DRF/INAC/SPINTEC/SPINTEC

04 38 78 52 98

Thesis supervisor :

Benoît MIRAMOND

Université Nice Sophia Antipolis - LEAT (Laboratoire d'Electronique, Antennes et Télécommunications) UMR CNRS 7248

04.92.94.28.84

Laboratory link : http://www.spintec.fr/

Hardware neural network implementation is a hot topic in research and is now considered as strategic for several international companies. Leading projects in neuromorphic engineering have led to powerful brain-inspired chips such as SyNAPSE, TrueNorth and SpiNNaker. Most of these technologies work well in centralized computing farms but will not fit embedded systems or Internet-of-Things (IoT) requirements, due to their energy consumption. Heterogeneous integration between CMOS and emergent technologies is seen as an opportunity to go past this limitation. In particular, Magnetoresistive Random-Access Memory (MRAM) is considered one of the most promising Non-Volatile Memory (NVM) technology expected to mitigate energy consumption when integrated in computing architectures. However, we still miss a high-level perspective on how NVM actually benefits energy efficiency and how it can be improved any further.

In this context, the aim of the thesis is to enable exploration of NVM-based neuromorphic accelerators by defining a framework for the joint, high-level modelling of digital logic and NVM-based functions. The framework will enable exploration of new architectural choices based on NVM properties to understand how they affect the performance/energy/area trade-off.

The thesis will be supervised by Professor Benoît Miramond (University Côte d’Azur, LEAT, Sophia Antipolis) and co-supervised by François Duhem (CEA/Spintec, Grenoble).

Applicants should have background in RTL development, system architecture, electronics and programming language such as C/C++ (SystemC appreciated).

MRAM-based synchronous integrated circuit design on advanced technology node for space applications

SL-DRF-18-0178

Research field : Electronics and microelectronics - Optoelectronics
Location :

Spintronique et technologie des composants

Laboratoire Spintec

Grenoble

Contact :

Gregory DI PENDINA

Lionel TORRES

Starting date : 01-10-2018

Contact :

Gregory DI PENDINA

CEA - DSM/INAC/SPINTEC/SPINTEC

0438784746

Thesis supervisor :

Lionel TORRES

Université de Montpellier - LIRMM

04 67 41 85 67

Personal web page : http://inac.cea.fr/Pisp/gregory.dipendina/index.html

Laboratory link : http://www.spintec.fr/

Nowadays, there are several methods to design microelectronics circuits adapted to space applications, meeting the radiation hardening constraints, using specific techniques or fabrication processes.

After a 3 year strong and rich experience in the framework of a Ph. D. in collaboration with CNES, LIRMM and CEA/Spintec, from 2014 to 2017, we would like to expand and reinforce this work. We want to propose novel design architectures embedding emerging non volatile technologies, such as spintronics using MRAM (magnetic memories), for harsh environment, especially for space. Several study have already been done or are currently ongoing on MRAM memories. However, we propose here to integrate MTJ (magnetic Tunnel Junctions), basic element of MRAM, into the computational logic. These MTJs can be used in sequential parts such as flip-flop and latches, or into cells such as NAND, NOR, etc. The final aim is to propose an hybrid CMOS/MRAM logic to harden integrated circuits against space environment. This subject addresses computational digital circuits such as microprocessors for instance. Moreover, STT-MRAM (Spin Transfer Torque) which is the most advanced MRAM technology which start to be commercialized will be used for this work.

On the other hand, the SOT-MRAM (Spin Orbit Torque) technology which is the most emerging MRAM one will also be considered in order to provide the most complete study and the most efficient solution. This work is very prospective and will use very advanced CMOS process. The goal is to fabricate a complete demonstrator and to perform functional and radiation tests with the CNES to validate the robustness of such an approach CMOS/MRAM against particle strikes. This Ph. D. would be mainly co-supervised by the Spintronics IC design team at CEA/Spintec Grenoble and supervised by LIRMM - Montpellier.

Development of 3D graphene/Si nanostructures nanocomposites for ultrastable supercapacitor

SL-DRF-18-0318

Research field : Materials and applications
Location :

SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé

Conception d’architectures moléculaires et processus électroniques

Grenoble

Contact :

Florence DUCLAIROIR

Lionel DUBOIS

Starting date : 01-11-2018

Contact :

Florence DUCLAIROIR

CEA - DSM/INAC/SYMMES/CAMPE

04 38 78 53 68

Thesis supervisor :

Lionel DUBOIS

CEA - DSM/INAC/SyMMES/CAMPE

04 38 78 92 57

Graphene is a material that is being widely explored for its potential applications notably in the field of energy (batteries, supercapacitor, fuel-cell catalyst…). Indeed it was described that graphene could be used as additive for the development of new negative electrodes for Li-ion batteries for example. In parallel, Si nanostructures (SiNSs) have been developed and tested in micro-supercapacitor cells and showed an amazing long cyclability (over millions of cycles) while the specific capacitance achieved could be improved.

The aim of this PhD project, conducted in collaboration between INAC/SyMMES and INAC/PHELIQS, is to develop methods to stabilize the Si nanostructures/electrolyte interface and to grow these Si NSs inside a graphene structured matrix to increase the surface area and thereby increase the capacitive properties of the micro-supercapacitor in terms of specific capacitance, power and energy densities. The growth of Si NSs inside a graphene matrix will also allow to decouple the NSs from a 2D substrate. Thus higher amount of material may be obtained, and supercapacitor rather than micro supercapacitor applications will be tested.

Production of short duration high brightness neutrons by interaction of a very high-power laser with a cryogenic target

SL-DRF-18-0828

Research field : Mechanics, energetics, process engineering
Location :

Service des Basses Températures

Laboratoire Cryogénie Fusion

Grenoble

Contact :

Denis CHATAIN

Nicolas LUCHIER

Starting date : 01-10-2018

Contact :

Denis CHATAIN

CEA - DRF/INAC/SBT/LCF

04 38 78 50 28

Thesis supervisor :

Nicolas LUCHIER

CEA - DRF/INAC/SBT/L3C

0438783068

Neutrons are very interesting tools for material sounding due to their capacity to penetrate into heavy materials and the possibility of exploiting specific diffusion resonance. Neutron sources used today are either very compact, but with a relatively low flux, or able of generating high flux, but they have then big sizes (based on particle accelerators) and their pulse duration are rather long (µs), what limits the temporal resolution of the aimed sounding. New perspectives are offered in this domain by lasers of high power. Indeed, it was demonstrated that we could, by the interaction between a laser and a suitably adapted target, generate intense neutron beams with durations lower than one nanosecond. A hard point to be validated concerns the repetition rate of these neutron sources, which should be adapted to the repetition rate (of the order of Hz) of new intense lasers.

The thesis will consist in putting together the optimal laser / target couple available today to make a neutron source. Indeed, two laboratories, world leaders in their domain: the LULI, coordinator of the installation APOLLON, expert in big laser installations and in laser / plasma interaction, and the SBT (Low Temperature Department of CEA/GRENOBLE), inventor of the target "ELISE", cryostat producing ribbons of solid Hydrogen for laser / plasma interaction join together to develop and test a neutron source based on the interaction of the laser beam APOLLON with a solid Hydrogen (or Deuterium) target.

The subject consists in characterizing and in optimizing the ribbon of solid Hydrogen, in devising the measure by neutronic imaging, and in characterizing the laser / plasma interaction to establish at best the laws of neutron generation by laser. The thesis will take place at first at the CEA/GRENOBLE, then at the LULI, with a co-supervision of both laboratories. The realized experiments should allow to determine the characteristics that should have a neutron source adapted to the non-destructive control.

Coupling CMOS silicon hole spin qubits to superconducting resonators

SL-DRF-18-0566

Research field : Mesoscopic physics
Location :

Photonique, Electronique et Ingénierie Quantiques

Laboratoire de Transport Electronique Quantique et Supraconductivité

Grenoble

Contact :

Romain MAURAND

Marc SANQUER

Starting date : 01-09-2018

Contact :

Romain MAURAND

CEA - DRF/INAC/PHELIQS/LATEQS

0438783732

Thesis supervisor :

Marc SANQUER

CEA - DRF/INAC/PHELIQS/LATEQS

04 76 38 43 67

With the miniaturization of electronic devices, the semiconductor industry has to deal with complex technical barriers and is forced to introduce novel and innovative concepts. The present project is exactly in line with this new paradigm as it proposes to divert CMOS technology to explore a new path for quantum spintronics. Concretely the project aims at using spin-orbit interaction present in the valence band of silicon to drive ultra-fast and ultra-coherent hole spin quantum bits (qubits). The project builds on the first demonstration by our Lab of a hole spin qubit electrically driven in silicon.

While spins are excellent quantum bits, their long-range coupling remains a challenge to tackle towards complex quantum computing architectures. Here we propose to take up this challenge using a microwave photon as a quantum mediator between qubits in silicon. The project presents a unique approach by leveraging a standard silicon-on-insulator CMOS process for the implementation of the qubits co-integrated with superconducting microwave resonators.

In this project you will work with silicon CMOS hole spin qubits to explore the physical limitations to hole spin coherence and to qubit gate fidelity. You will fabricate superconducting microwave resonators on silicon co-integrated eventually with the spin qubits. You will work at temperatures as low as 10 mK and magnetic fields as high as 9 Tesla. High frequency electronic measurements to manipulate the spin states and to readout the superconducting resonators will be applied.

Quantum dots connected to silver nanoparticles as redox photocatalysts working with visible light

SL-DRF-18-0393

Research field : Physical chemistry and electrochemistry
Location :

SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé

Conception d’architectures moléculaires et processus électroniques

Grenoble

Contact :

Vincent MAUREL

Jean-Marie MOUESCA

Starting date : 01-10-2018

Contact :

Vincent MAUREL

CEA - DRF/INAC/SYMMES/CAMPE

04 38 78 35 98

Thesis supervisor :

Jean-Marie MOUESCA

CEA - DRF/INAC/SYMMES/CAMPE

04 38 78 30 13

In this project we propose to investigate a new class of photocatalysts based on colloidal quantum dots that are expected to be i/ efficient with visible light and iii/ able to photocatalyze redox reactions in smooth conditions, as shown by a recent study in our laboratory.

The PhD project will consist in two mains parts. First, some well-known quantum dots systems (CdS, CdSe, ZnSe, ...) will be investigated as redox photocatalysts for new radicalar reactions recently developped for fine organic synthesis.

Second the PhD student will developp and new controlled size connection’s of quantum dots with silver nanoparticles by a click chemistry approach (Huisgen cycloaddition of azides and alkynes). Such assemblies quantum dots/ silver nanoparticles will promote the electron/hole separation by electron transfer from the quantum dots to the silver nanoparticles and should enable us to improve the efficiency of quantum dots based photocatalytic systems.

Improving DNP-enhanced NMR for the advanced study of glycopolymers

SL-DRF-18-0986

Research field : Physical chemistry and electrochemistry
Location :

Modélisation et Exploration des Matériaux

Laboratoire de Résonance Magnétique

Grenoble

Contact :

Sabine HEDIGER

Gaël DE PAEPE

Starting date : 01-10-2018

Contact :

Sabine HEDIGER

CNRS - DRF/INAC/MEM/RM

+33438786579

Thesis supervisor :

Gaël DE PAEPE

CEA - DRF/INAC/MEM/RM

04 38 78 65 70

Personal web page : http://inac.cea.fr/Pisp/gael.depaepe/

Laboratory link : http://inac.cea.fr/Phocea/Vie_des_labos/Ast/ast_visu.php?id_ast=1111

INAC (Institute for Nanoscience and Cryogenics, CEA Grenoble) has a PhD opening for a physical chemist. The PhD will deal with the development and application of a new and emerging hyperpolarization technique: high-magnetic field MAS-DNP (Magic Angle Spinning Dynamic Nuclear Polarization). This approach is used to hyperpolarize nuclei such that high-sensitivity and high-resolution solid-state NMR (Nuclear Magnetic Resonance) spectra can be obtained and used to extract important structural information at the atomic scale, such as surface functionalization and internuclear proximities/distances, as well as crystallographic data, etc.

Since the potential of this technique is beginning to be realized, the aim of this PhD is to further develop the methodology (sample preparation, new polarizing agents and radio-frequency pulse schemes) for the study of complex glycopolymers. This will be achieved through the combined use of EPR, DNP and MAS-DNP numerical simulation as well as developing advanced NMR experiments.



The thesis will mainly be performed in the DNP group of the Institute for Nanosciences and Cryogenics (CEA/University Grenoble Alpes) (http://www.dnpgrenoble.net/) in the context of international and industrial collaborations (NHMFL Tallahassee, Florida and Bruker Biospin). It will take place in a highly dynamical environment at the MINATEC campus (CEA Grenoble) within the MEM laboratory (CEA INAC) where the DNP group, in collaboration with the Bruker company (world leader in NMR instrumentation), is currently pushing the development and use of this technique (high magnetic field DNP) far beyond its state-of-the-art. The group has two high-field MAS-DNP systems and has successfully conducted instrumental and methodological developments in the subsequent years. Notably, the group has built equipment that can sustainably cool large flows of Helium gas and thus consequently has access to MAS-DNP performed at very low temperatures (10-100 K), which opens a whole realm of experimental possibilities.



This PhD work will take place within a larger ERC-funded project (PI G. De Paëpe) involving strong partnerships between academic laboratories and industrial partners.

Harvesting electricity from salinity gradients

SL-DRF-18-0874

Research field : Soft matter and complex fluids
Location :

SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé

Synthèse, Structure et Propriétés de Matériaux Fonctionnels

Grenoble

Contact :

Stefano MOSSA

Starting date :

Contact :

Stefano MOSSA

CEA - DRF/INAC/SyMMES/STEP

04 38 78 35 77

Thesis supervisor :

Stefano MOSSA

CEA - DRF/INAC/SyMMES/STEP

04 38 78 35 77

Personal web page : https://stefano-mossa.weebly.com/

New concepts in energy harvesting are the focus of a tremendous scientific activity. In particular, very recent electric power production schemes exploit electrochemical devices in the presence of gradients of different nature. In this project we intend to clarify a few aspects of the physics behind these applications employing salinity gradients by using Molecular Dynamics (MD) computer simulation.

High-resolution TEM magnetic imaging of nanotubes for spintronics

SL-DRF-18-0518

Research field : Solid state physics, surfaces and interfaces
Location :

Spintronique et technologie des composants

Laboratoire Spintec

Grenoble

Contact :

Olivier FRUCHART

Starting date : 01-09-2018

Contact :

Olivier FRUCHART

CNRS - INAC-Spintec

0684206871

Thesis supervisor :

Olivier FRUCHART

CNRS - INAC-Spintec

0684206871

Personal web page : https://cv.archives-ouvertes.fr/olivier-fruchart

Laboratory link : http://www.spintec.fr/research/spin-textures/

More : http://fruchart.eu

The objective of the internship is the study by transmission electron microscopy (TEM) of magnetic nanotubes chemically synthesized. We are studying these as model objects to explore the concept of information storage in a 3D magnetic medium, based on the propagation of magnetic walls along one-dimensional structures. Physico-chemical study of the material and magnetic imaging at the nanometer scale will be used to explore and understand the arrangement of domains and domain walls in these systems, whose synthesis has been achieved recently.

The experimental techniques that will be used will be chemical and structural analysis by electron diffraction and high-resolution imaging, magnetic imaging and electron holography, in a transmission electron microscope. The student will perform sample preparation for electron microscopy, the installation of a device for an observation in the microscope, and imaging.

Microscopy will be conducted in close collaboration with INAC-MEM-LEMMA a,d LETI. The work also includes an aspect of processing, interpretation of data and participation in micro-magnetic simulations to assist physical understanding. These will be done in collaboration with the laboratory of simulation group SPINTEC / NEEL.

Manipulation of spin currents and magnetic state at the nanoscale using the spin orbit coupling

SL-DRF-18-0058

Research field : Solid state physics, surfaces and interfaces
Location :

Spintronique et technologie des composants

Laboratoire Spintec

Grenoble

Contact :

Laurent VILA

Jean-Philippe ATTANE

Starting date : 01-10-2018

Contact :

Laurent VILA

CEA - DRF/INAC/SPINTEC/SPINTEC

0438780355

Thesis supervisor :

Jean-Philippe ATTANE

Université Grenoble Alpes - DRF/INAC/SPINTEC/SPINTEC

0438784326

Personal web page : http://inac.cea.fr/Pisp/laurent.vila/

Laboratory link : http://www.spintec.fr/research/spin-orbitronics/

The development of spin electronics, or spintronics, allows to imagine many devices taking advantage of an electronics no longer based solely on the electrical charge of the carriers but also on their spin. This new degree of freedom offers additional means of conveying information, and introduces new ways to manipulating it.

Very recently, a collection of Spin Orbit based spin- to-charge interconversion mechanisms (Spin Hall effects, Rashba and Topological Insulators) were observed experimentally. It appears in the set of non-magnetic metals, semiconductors or oxydes, and sorts the carriers according to their spin state. It allows injecting and detecting spins without necessarily using magnetic materials or a magnetic field, which is both conceptually and technologically very interesting.

In this framework, we wish to create lateral nanostructures taking advantage of pure spin current generated by harnessing the Spin Orbit coupling for both spin to charge interconversion mechanisms and the manipulation of magnetization state of nano-object (dot or magnetic domain wall) by absorption of this current and spin transfer torque. Material of interest will be metals, oxydes and topological insulators to generate or detect spin currents, and will be applied to the manipulation of the magnetic state of a nanoelement, an example of a recent realization being given on the figure.

If subjects related to the spin transfer by absorption of a pure spin current are very competitive, they are scientifically rich, and currently booming. This area of research is still largely open to exploration, and we are benefiting from our recent development of efficient injection and detection devices.

The proposed topic lies in basic research but with a clear opening towards applied research. The trainee will benefit from the technical and scientific environment of the laboratory, and the collaborations put in place with the major actors of the field at the international level. This project is supported by funding from the ANR.

Heat transport in solids, beyond the classical approximation

SL-DRF-18-0848

Research field : Solid state physics, surfaces and interfaces
Location :

SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé

Synthèse, Structure et Propriétés de Matériaux Fonctionnels

Grenoble

Contact :

Stefano MOSSA

Jean-Louis BARRAT

Starting date :

Contact :

Stefano MOSSA

CEA - DRF/INAC/SyMMES/STEP

04 38 78 35 77

Thesis supervisor :

Jean-Louis BARRAT

Université Grenoble Alpes - LiPhy

Personal web page : http://stefano-mossa.weebly.com/

Heat transport in materials is a key property for a number of applications, and significant efforts are devoted to the design of materials with high (for heat transport applications) or low (e.g., for thermoelectric conversion) heat conductivity. It may then come as a surprise, that, in spite of the many developments in microscopic modeling of materials in the last 40 years, we still lack a well established, general method for computing thermal conductivities in insulating (or poor electrical conductors) solid materials. The goal of the project is to establish such a methodology, using the formalism of path integrals that allows one to take into account accurately nuclear quantum effects in condensed systems.

Theoretical investigation of finite-temperature spin dynamics

SL-DRF-18-0324

Research field : Solid state physics, surfaces and interfaces
Location :

Photonique, Electronique et Ingénierie Quantiques

Groupe Théorie

Grenoble

Contact :

Mike ZHITOMIRSKY

Starting date : 01-10-2018

Contact :

Mike ZHITOMIRSKY

CEA - DRF/INAC/PHELIQS/GT

04.38.78.43.30

Thesis supervisor :

Mike ZHITOMIRSKY

CEA - DRF/INAC/PHELIQS/GT

04.38.78.43.30

Computer simulations play an increasingly important role in our exploration of Nature. The Monte Carlo modeling of spin systems is one of the true success stories of the computer-aided theoretical studies. At the same time, numerical and analytical investigation of the dynamic properties of magnetic systems is far less mature with the majority of theoretical works employing the phenomenological Landau-Lifshitz-Gilbert equations.

This PhD project is focused on an alternative microscopic approach based on the material-specific spin Hamiltonians that describe interactions between atomic magnetic moments. The numerical spin dynamics computations in real time have to be combined with the thermal Monte Carlo calculations. This will allow to model magnetic materials at an arbitrary temperature above and below the possible magnetic transitions. The obtained results will be of direct relevance to a wide range of experimental studies performed on neutron and synchrotron facilities as well as to the field of spintronics and nanomagnetism.

Formation and stabilization of size-controlled graphene nanopores for gas filtration application

SL-DRF-18-0519

Research field : Solid state physics, surfaces and interfaces
Location :

Modélisation et Exploration des Matériaux

Laboratoire d'Etude des Matériaux par Microscopie Avancée

Grenoble

Contact :

Hanako OKUNO

Gilles CUNGE

Starting date : 01-10-2018

Contact :

Hanako OKUNO

CEA - DRF/INAC/MEM/LEMMA

04 38 78 20 73

Thesis supervisor :

Gilles CUNGE

CNRS - CNRS/LTM

0438782408

The introduction of nanoscale pores in graphene has attracted much attention for a large variety of applications that involve water purification, gas filtration, chemical separation, and DNA sequencing. Graphene has been proposed as an effective separation membrane. Removing carbon atoms to form size-controlled nanopores, size-selective separation membrane might be possible based on the molecular sieving effects.

In this Thesis project, we aim at studying formation mechanism and edge natures of sub-nanometer size nanopores in graphene for gas filtration membrane application. The final objective is to realize size-controlled stable nanopores in graphene monolayers using plasma technology and to integrate the developed nanopore formation process into gas filtration membrane technology to test their selectivity especially on hydrogen separation.

Miniature and ultra-sensitive magnetometer for space missions

SL-DRF-18-0141

Research field : Solid state physics, surfaces and interfaces
Location :

Spintronique et technologie des composants

Laboratoire Spintec

Grenoble

Contact :

Hélène BEA

Claire BARADUC

Starting date : 01-10-2018

Contact :

Hélène BEA

UGA - DRF/INAC/SPINTEC/SPINTEC

04 38 78 08 46

Thesis supervisor :

Claire BARADUC

CEA - DRF/INAC/SPINTEC/SPINTEC

04 38 78 42 35

Laboratory link : http://www.spintec.fr/research/magnetic-sensors/

The aim is to develop a miniature and ultra-sensitive magnetometer (100 fT / Hz^1/2), using magnetic tunnel junctions and microfabrication techniques from microelectronics. This magnetometer could replace the magnetometers currently used on space missions with a mass reduction by a factor of 100. This extreme lightness (~ 1 g without electronics) would represent a competitive advantage over inductive sensors currently used in space missions (mass > 1 kg).

The proposed magnetometer combines a magnetic tunnel junction as sensing element of the sensor, a flux concentrator to amplify the field to be measured, and a magnetic field modulation system to reduce the noise of the measurement. Preliminary studies have shown the feasibility of the basic bricks of this sensor. It is now necessary to optimize the flux concentrator and the magnetic tunnel junction, in particular by developing an innovative junction that is currently the subject of a patent application.

The thesis work will mainly be experimental (microfabrication, electrical and magnetic characterization, noise measurements, magnetic imaging) but will also include analysis and micromagnetic simulations.

Theoretical study of advanced magnetocaloric materials

SL-DRF-18-0177

Research field : Solid state physics, surfaces and interfaces
Location :

Photonique, Electronique et Ingénierie Quantiques

Groupe Théorie

Grenoble

Contact :

Mike ZHITOMIRSKY

Starting date : 01-10-2018

Contact :

Mike ZHITOMIRSKY

CEA - DRF/INAC/PHELIQS/GT

04.38.78.43.30

Thesis supervisor :

Mike ZHITOMIRSKY

CEA - DRF/INAC/PHELIQS/GT

04.38.78.43.30

Laboratory link : http://inac.cea.fr/Phocea/Vie_des_labos/Ast/ast_groupe.php?id_groupe=1157

An external magnetic field affects the entropy of a magnetic system and provokes temperature variations which can be used for magnetic refrigeration. Such an alternative cooling technology is increasingly important nowadays for space telescopes, particle physics experiments and quantum computing. The existing adiabatic demagnetization refrigerators utilize paramagnetic salts, which have limited capacity for temperatures above 1 K. Recently, two new families of magnetocaloric materials suitable for applications in the 1-4 K temperature range have been proposed: geometrically frustrated spin systems and dipolar magnets. We plan to study the magnetocaloric properties of such materials using large scale Monte Carlo simulations of realistic spin models appropriate for the known, Gd3Ga5O12 and GdLiF4, as well as for the prospective, Yb2Ti2O7 and Yb3Ga5O12, magnetocaloric materials. The theoretical study will benefit from a collaboration with the on-going experimental work at INAC.

Hybrid nanowires for topological quantum computing

SL-DRF-18-1006

Research field : Solid state physics, surfaces and interfaces
Location :

Photonique, Electronique et Ingénierie Quantiques

Laboratoire de Nano Physique des Semi-Conducteurs

Grenoble

Contact :

Moïra HOCEVAR

Starting date : 01-09-2018

Contact :

Moïra HOCEVAR

CNRS - DRF/INAC/PHELIQS/NPSC

0438783513

Thesis supervisor :

Moïra HOCEVAR

CNRS - DRF/INAC/PHELIQS/NPSC

0438783513

General Scope:

One interesting and promising proposal for quantum computation relies on the so-called topological protected quantum bits. Realizing such quantum bits depends on the ability to make materials that can host Majorana bound states. In 2012, signatures of such states were reported in one-dimensional semiconductors with high spin-orbit coupling, coupled to a superconductor [1]. Since then, nanostructured hybrid materials based on superconductor/semiconductor interfaces have received increased attention. Yet, controlled formation of topological protected states can only be realized if the superconductor/semiconductor interface is of high quality. Creating those interfaces in an epitaxial fashion would have many advantages, among them better transparency, controlled interface chemistry, higher current injection and lower disorder. However, combining crystalline metals and semiconductors is challenging because of the fundamental different properties of both families of materials. Recently, in-situ epitaxial growth of InAs/Al core/shell nanowires exhibited defect free and homogeneous interfaces [2]. The devices revealed a superconducting hard gap demonstrating the high potential of in-situ shell epitaxy. Here, we propose to develop novel interfaces using a higher critical field superconductor such as vanadium to reach the Majorana regime and to perform further topological experiments.

[1] V. Mourik et al 2012 Science 336(6084) 1003

[2] P. Krogstrup et al 2015 Nature Materials 14 400



Research topic and facilities available:

In this project, the student will carry out the growth of networks of hybrid nanowires in a III-V molecular beam epitaxy reactor in CEA/INAC. In particular, she/he will focus on InAs/V core/shell nanowire fabricated using templates developed in the cleanroom. The student will perform the characterization of the samples by SEM, EDX and/or TEM. Together with partner labs in the USA, she/he will participate in several low temperature measurement campaigns throughout the course of her/his PhD, as well as perform high-end structural studies using advanced equipment and facilities.

SL-DRF-18-0072

Research field : Solid state physics, surfaces and interfaces
Location :

Photonique, Electronique et Ingénierie Quantiques

Laboratoire Silicium Nanoélectronique Photonique et Structures

Grenoble

Contact :

Emmanuel PICARD

Pierre R. MARCOUX

Starting date : 01-09-2018

Contact :

Emmanuel PICARD

CEA - DRF/INAC/PHELIQS/SINAPS

04 38 78 90 97

Thesis supervisor :

Pierre R. MARCOUX

CEA - DRT/DTBS/SBSC/LCMI

04 38 78 15 04

Antiferromagnetic spintronics

SL-DRF-18-0274

Research field : Solid state physics, surfaces and interfaces
Location :

Spintronique et technologie des composants

Laboratoire Spintec

Grenoble

Contact :

Vincent BALTZ

Starting date : 01-10-2018

Contact :

Vincent BALTZ

CNRS - DFR/INAC/SPINTEC/SPINTEC

04 38 78 03 24

Thesis supervisor :

Vincent BALTZ

CNRS - DFR/INAC/SPINTEC/SPINTEC

04 38 78 03 24

Laboratory link : http://www.spintec.fr/research/antiferromagnetic-spintronics/

More : https://arxiv.org/ftp/arxiv/papers/1606/1606.04284.pdf

Antiferromagnetic materials (antiparallel alignment of the atomic magnetic moments) could represent the future of spintronic applications thanks to the numerous interesting features they combine: they are robust against perturbation due to magnetic fields, produce no stray fields, display ultrafast dynamics and are capable of generating large magneto-transport effects. Intense research efforts are being invested in unraveling spin-dependent transport properties in antiferromagnetic materials. Whether spin-dependent transport can be used to drive the antiferromagnetic order and how subsequent variations can be detected are some of the thrilling challenges to address.

The nature of the elements constituting the antiferromagnetic material and the quality of the interfaces will be the adjustable parameters. We will consider mainly the efficiency of spin injection and the interfacial filtering, the absorption of spins in the core of the material and the absorption characteristics lengths, the order temperatures and the magnetic susceptibility, and the efficiency of the spin-orbit coupling via the spin Hall effect.

This PhD thesis work is experimental. It will build on the many techniques of fabrication (sputtering, molecular beam epitaxy, clean room nanofabrication) and characterization (magnetometry, ferromagnetic resonance, transport) at SPINTEC and benefit from the collaboration with our partner laboratories for experiments with a resonant cavity and for access to complementary materials.

Study of physical properties of magnetic skyrmions for sensing applications

SL-DRF-18-0215

Research field : Solid state physics, surfaces and interfaces
Location :

Spintronique et technologie des composants

Laboratoire Spintec

Grenoble

Contact :

Claire BARADUC

Hélène BEA

Starting date : 01-09-2018

Contact :

Claire BARADUC

CEA - DRF/INAC/SPINTEC/SPINTEC

04 38 78 42 35

Thesis supervisor :

Hélène BEA

UGA - DRF/INAC/SPINTEC/SPINTEC

04 38 78 08 46

Laboratory link : http://www.spintec.fr/research/magnetic-sensors/

Skyrmions are chiral magnetic bubbles: magnetization follows a cycloid along a line across the skyrmion. They can appear in heavy metal/ferromagnet/oxide ultrathin trilayers. Such texture results from the presence of an interfacial interaction called Dzyaloskinskii-Moriya interaction. It makes the skyrmions stable, less sensitive to defects as compared to usual domain walls and easily moveable by electrical current. They are currently very popular as they could be used as dense storage nanoscale data bits, or for magnetic logic.

Their size may be modified by a magnetic field. Moreover, using magneto-optical microscopy, we have recently shown that a gate voltage can modulate the size and density of magnetic skyrmions in ultrathin films, ultimately leading to the realization of a skyrmion switch [1]. This new degree of freedom may thus allow to create multifunctional spintronic devices or to better control the skyrmion properties.



In order to develop skyrmion based spintronic devices, the objectives of this thesis would be:

-to better understand and control the different contributions in the Dzyaloshinskii-Moriya interaction by playing on the materials thanks to a support from theoreticians at Spintec.

- to optimize the tunability of skyrmion properties with the gate voltage by performing a material study. Skyrmion behavior with temperature will also be studied as a device should operate in the -40 to 100°C range for applications.

-to characterize the electrical signature of skyrmions by using magneto-optical microscopy coupled with magnetotransport. This electrical signal is necessary to read the state of a skyrmion-based device but is still a technological challenge, the signals being usually quite small.

- finally, to assess the potential for skyrmions to be used in spintronic devices.



[1] M. Schott et al. Nano Lett., 17, 3006 (2017)

Advanced AlGaN-based 1D nanostructure growth for UV emission

SL-DRF-18-0392

Research field : Solid state physics, surfaces and interfaces
Location :

Photonique, Electronique et Ingénierie Quantiques

Laboratoire de Nano Physique des Semi-Conducteurs

Grenoble

Contact :

Christophe DURAND

Joël EYMERY

Starting date : 01-10-2018

Contact :

Christophe DURAND

UGA - DRF/INAC/PHELIQS/NPSC

04 38 78 19 77

Thesis supervisor :

Joël EYMERY

CEA - DRF/INAC/MEM/NRS

04 38 78 30 15

The growth of GaN nanowires surrounded by GaN/InGaN quantum wells grown by MOVPE (Metal-Organic Vapor Phase Epitaxy) has been studied extensively in the laboratory and is now well mastered [1]. This is an important step forward as it makes possible the manufacturing and industrial production of nanowire-based LEDs for the emission of visible light (blue, green and white).

In the same way, we wish to develop new 1D nanostructures for the emission of UV light. Pioneering and promising results have been obtained in the laboratory using GaN/InAlN quantum wells grown around the GaN wires exhibiting emission at 330 nm up to room temperature [2]. By applied a in situ annealing, we have demonstrated the possibility of etching the GaN wires core, while preserving the optical properties of the quantum wells. Thus, we made for the first time quantum well-based tubes with excellent optical properties [3].

The aim of the thesis is to develop new quantum wells, such as GaN/AlGaN or AlGaN/AlN grown on 1D nanostructures (wires, tubes, bands, etc.), in order to be able to reach far UV emission wavelengths (<280 nm) with the possibility destroying bacteria. This is a major challenge for the development of UV LEDs considering new applications such as water treatment or sterilization. The purpose of this study is to better understand the potentiality of 1D nanostructures to emit far UV. This type of quantum well grown on 1D nanostructures also makes possible the realization of IR subband detectors in the THz domain.

The development of several stages will be necessary to carry out this thesis project: (i) the realization of 1D nanostructures in Al(Ga)N by combining growth and selective etching, (ii) epitaxy of AlGaN-based quantum wells grown on these nanostructures, (iii) advanced structural and optical characterization, and (iv) the design of new devices and their favrication. The thesis will be based on a collaborator network (C2N, EPFL, Univ. Tyndall ...) in order to progress effectively.

The work is essentially experimental to explore fundamental phenomena at the nanometer scale while participating in a active research topic on the development of new LED devices for UV emission.



[1] R. Koester et al., Nano Lett. 11, 4839 (2011).

[2] C. Durand et al., ACS Photonics 1, 38 (2014).

[3] C. Durand et al., Nano Lett. 17, 3347 (2017).



Defect engineering for quantum computing

SL-DRF-18-0834

Research field : Solid state physics, surfaces and interfaces
Location :

Modélisation et Exploration des Matériaux

Laboratoire de Simulation Atomistique

Grenoble

Contact :

Damien CALISTE

Pascal POCHET

Starting date : 01-09-2018

Contact :

Damien CALISTE

CEA - DRF/INAC/MEM/L_Sim

0438783518

Thesis supervisor :

Pascal POCHET

CEA - DRF/INAC/MEM/L_Sim

04 38 78 28 60

Personal web page : http://inac.cea.fr/pisp/damien.caliste/

Laboratory link : http://inac.cea.fr/Phocea/Vie_des_labos/Ast/ast_groupe.php?id_groupe=12

More : http://mechaspin.neel.cnrs.fr/

L_Sim group in Univ. Grenoble Alpes, is opening one PhD position for a young researcher in material sciences. L_Sim is a numerical simulation group, specialized in material studies at atomistic levels, working in collaboration with experimentalist groups. The position aims at studying point defects in semi-conducting bulk compounds. The work is part of a funded experimental project (http://mechaspin.neel.cnrs.fr) which targets the elaboration of isolated defects in II-VI or III-V semi-conductors. The control of such defect should give a new platform for

quantum computing.



The applicant will base his work on DFT calculations, extracting thermodynamic and kinetic parameters, and effect on band structure.

Numerical and analytical studies on the synchronisation of spintorque oscillators

SL-DRF-18-1012

Research field : Solid state physics, surfaces and interfaces
Location :

Spintronique et technologie des composants

Laboratoire Spintec

Grenoble

Contact :

Ursula EBELS

Liliana-Daniela BUDA-PREJBEANU

Starting date : 01-10-2018

Contact :

Ursula EBELS

CEA - DRF/INAC/SPINTEC/SPINTEC

0438785344

Thesis supervisor :

Liliana-Daniela BUDA-PREJBEANU

Grenoble INP - DRF/INAC/SPINTEC/SPINTEC

04 38 78 44 19

Spintorque oscillators are based on magnetic tunnel junctions that provide a large oscillating output voltage signal in the GHz range when driving it with a DC current. The spin momentum counter-acts natural damping and can drive the magnetization into large angle steady state oscillations, which are converted into an electrical signal via the magneto-resistance. While in the past many studies have been realized on single spintorque oscillator devices, currently efforts concentrate on the coupling of different oscillators to enhance output signal levels and potentially reduce noise. Coupling and synchronisation of these oscillators can occur via electrical or dipolar interactions. This thesis will undertake a simulation study of the mutual synchronisation of such uniformly magnetized structures and will develop where possible an analytical frame work based on the descriptions we have developed within the group for injection locking to an external signal source. The different coupling mechanism are dipolar fields or the mutual rf current. The questions to address concern how the different coupling mechanisms influence the locking process, in particular the coupling phase. This will be of importance when more than two oscillators will be coupled that are not identical and that will compete with each other. Identifying the parameters that lead to stable coupling or chaotic states are of special interest.

Interaction effects on topological properties of multiterminal Josephson junctions

SL-DRF-18-0289

Research field : Theoretical Physics
Location :

Photonique, Electronique et Ingénierie Quantiques

Groupe Théorie

Grenoble

Contact :

Julia MEYER

Manuel HOUZET

Starting date : 01-10-2018

Contact :

Julia MEYER

Université Grenoble Alpes - DRF/INAC/PHELIQS/GT

04.38.78.31.46

Thesis supervisor :

Manuel HOUZET

CEA - DRF/INAC/PHELIQS/GT

04.38.78.90.44

Personal web page : http://inac.cea.fr/Pisp/manuel.houzet/

Laboratory link : http://inac.cea.fr/en/Phocea/Vie_des_labos/Ast/ast_groupe.php?id_groupe=501

There is currently an active search for new phases of matter that admit topologically protected edge states. A promising route to realize them consists in combining conventional materials into appropriate heterostructures. Multiterminal Josephson junctions between conventional superconductors may be considered as topological materials themselves. As an example, 4-terminal junctions can accommodate topologically protected zero-energy bound states, which form so-called Weyl singularities. Their existence may be revealed through a quantized transconductance, like in the quantum Hall effect, but without magnetic field. The aim of the project will be to explore further this recent idea by investigating theoretically the robustness of this prediction in the presence of local Coulomb repulsion within the junction. In particular, the fate of Weyl singularities will be analyzed within an actual quantum-dot model for the junction.

Contribution to thermal modelisation and oscillating flow dynamics applied to pulse tube cooler

SL-DRF-18-0851

Research field : Thermal energy, combustion, flows
Location :

Service des Basses Températures

Laboratoire Cryoréfrigérateurs et Cryogénie Spatiale

Grenoble

Contact :

Sylvain MARTIN

Shihe XIN

Starting date : 01-09-2018

Contact :

Sylvain MARTIN

CEA - DRF/INAC/SBT/LCCS

+ 33 4 38 78 31 71

Thesis supervisor :

Shihe XIN

INSA Lyon - CETHIL (UMR 5008 INSA/CNRS/UCBL) Groupe Transferts Convectifs

04.72.43.70.77

The Low Temperature Laboratory (SBT) from CEA/INAC is involved in technological cryogenic research in a large temperature range from 120 K down to few tens of millikelvins. CETHIL (CNRS, INSA, UCBL) has a strong expertise in numerical simulation for systems involving flow study coupled to thermal transfer.



In SBT, the LCCS team (Cryocoolers and space cryogenics lab) develops small cryocoolers ranging from 50 mK up to 50 K. Among those developments, the pulse tube is a key component in the team. Based on the Stirling thermodynamic cycle, it allows to reach temperature between 4 K and 100 K with helium. They are used in satellite for earth observation (MTG, Met-Image) around 50 K. For space observation mission (ATHENA/X-IFU), a system able to reach 15 K has been developed and a prototype demonstrates an ultimate temperature of 4 K.

In CETHIL, the involved team has a strong expertise in numerical simulation of thermal transfer in fluid media. They are using CFD simulation and have developed their own numerical simulation dedicated to thermal studies. The team is also using massive parallel computation.



Based on the expertise of the 2 laboratories, the aim of the internship is to develop a model of a pulse tube that allows to cover the temperature range of 100 K – 4 K. A better comprehension of the phenomena inside the pulse tube is expected. Hence, a faster improvement of the performances. A combination of thermal modelling and oscillating flow dynamics for real gas is needed. The tool shall also be able to size multi-stage systems (Dual stage pulse tube, 15 K PT …). The model will be compared to experimental results already available in SBT but also on dedicated test bench to validate some sub-system of a pulse tube cooler. The test bench shall be developed during the PhD.



The PhD thesis will be both in Lyon at CETHIL laboratory for numerical simulation and in Grenoble at SBT for the experimental time.



The candidate shall have a master degree in the field of the thermal study, mechanic or energetic. He shall have background in thermodynamics, thermal transfer and simulation with an interest for thermal machines and physics.

Inertial Confinement and Centimetric Cavity Collapse

SL-DRF-18-0218

Research field : Thermal energy, combustion, flows
Location :

Service des Basses Températures

Laboratoire Cryogénie Fusion

Grenoble

Contact :

Jérome DUPLAT

Starting date : 01-09-2017

Contact :

Jérome DUPLAT

Université Grenoble Alpes - DRF/INAC/SBT/LCF

04 38 78 64 89

Thesis supervisor :

Jérome DUPLAT

Université Grenoble Alpes - DRF/INAC/SBT/LCF

04 38 78 64 89

In the frame of the research on the inertial confinement to obtain the nuclear fusion, we intend to study the collapse dynamics of large nearly-void spherical bubble inside a liquid, provoking the inertial confinement of the matter trapped inside the cavity.

This process is similar to sonoluminescence experiment or to inertial confinement fusion experiement. However, our original setup allows to work at larger length and time scales,

and then allow the direct observation of all thermodynamical and hydrodynamical phenomena.



Preliminar experiments indicates that temperature higher than 20000 K can be reached, and maybe much more.



The experimental work will be a base for developing physical models.

Monitoring formation and repair of DNA damage by a non-invasive assay

SL-DRF-18-0317

Research field : Toxicology
Location :

SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé

Chimie Interface Biologie pour l’Environnement, la Santé et la Toxicologie

Grenoble

Contact :

Thierry DOUKI

Starting date : 01-10-2018

Contact :

Thierry DOUKI

CEA - DRF/INAC/SyMMES/CIBEST

0438783191

Thesis supervisor :

Thierry DOUKI

CEA - DRF/INAC/SyMMES/CIBEST

0438783191

A wide variety of physical and chemical agents may damage the chemical structure of DNA, and in particular nucleic bases. As a consequence, mutations are produced that may trigger the cancerization of the damage cell. Fortunately, all cells have developed a series of enzymatic processes that can repair the damaged portion of DNA and limit the deleterious consequences of the damage. The effect of genotoxic agents results thus from the balance between the formation and the repair of DNA damage.

Monitoring the formation of DNA damage in Human requires collection of tissues, followed by extraction of DNA and analysis. Although internal organs may sometimes be studied when biopsies are taken in patients, samples available in the general population or at the working place are limited to skin biopsies and blood cells. Biopsies is a rather invasive procedure and the nature of the damage in blood cells does not represent the whole body exposure. Some limitations are also encountered in in vitro experiments. There is thus a need for less invasive procedures and more representative data.

In the present PhD project, we want to quantify the damages bases released from DNA by the repair enzymes. In particular, we want to quantify bulky adducts and photoproducts resulting from exposure to solar light. The work will first involve extensive analytical chemistry developments, using mostly solid phase extraction and HPLC associated to mass spectrometry. On-line HPLC preparation of the samples will also be investigated. The method will be then validated on cultured cells. Last, the protocol will be extended to the detection of repair products in biological fluids like urine for in vivo investigations. The technique will be applied to three main topics: the formation of photoproducts induced by solar UV in skin and its prevention by sunscreens (collaboration with the Pierre Fabre Dermo-Cosmétique company), the induction of adducts with pollutants like polycyclic aromatic hydrocarbons, and the formation of adducts between DNA and CEES, an analog of sulfur mustard (collaboration with the Military Biomedical Research Institute).

Noninvasive assays for the assessment of exposure to chemical warfare agents

SL-DRF-18-0555

Research field : Toxicology
Location :

SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé

Chimie Interface Biologie pour l’Environnement, la Santé et la Toxicologie

Grenoble

Contact :

Thierry DOUKI

Starting date : 01-10-2018

Contact :

Thierry DOUKI

CEA - DRF/INAC/SyMMES/CIBEST

0438783191

Thesis supervisor :

Thierry DOUKI

CEA - DRF/INAC/SyMMES/CIBEST

0438783191

Personal web page : http://inac.cea.fr/Pisp/65/thierry.douki.html

Use of chemical warfare agents is a current concern shown in several recent conflicts and associate to terrorist threat. Availability of biomonitoring assays for the identification of toxic compounds and assessment of individual exposure is an important challenge. Sulphur mustard, a chemical warfare agents belonging to the vesicants family, and its simulant CEES will be the focus of this PhD work.

A first class of potential biomarkers are the damage induced to DNA bases by sulphur mustard and CEES. In order to avoid DNA extraction from exposed tissues, we will take advantage of the ability of cells to remove and release the damaged portions of DNA. We will develop an assay for the quantification of these repair products in biological fluids. The other type of biomarkers is related to the detoxification mechanisms used by cells. Electrophilic compounds like sulphur mustard and CEES react, either chemically or enzymatically, with glutathione, a tripeptide present in large amounts in cells. We will develop an analytical approach for the detection of the glutathione-sulphur mustard/CEES conjugates in urine.

For this PhD work, it will be necessary to work first in cultured cells or ex-vivo skin explants in order to define the chemical form and the excretion kinetics of the targeted biomarkers. Analytical tools for the detection these compounds are already available in the group but nothing has been optimized for their isolation from extracellular media or biological fluids. The analytical developments will thus focus on sample preparation using solid phase extraction techniques followed by quantification by HPLC associated to mass spectrometry. These approaches validated for the quantification of the biomarkers in biological fluids will be applied to animal studies in collaboration with the Military Biomedical Research Institute.

SiNW composites in high energy density lithium-ion batteries

SL-DRF-18-0291

Research field : Ultra-divided matter, Physical sciences for materials
Location :

SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé

Synthèse, Structure et Propriétés de Matériaux Fonctionnels

Grenoble

Contact :

Cédric HAON

Pascale CHENEVIER

Starting date : 01-10-2018

Contact :

Cédric HAON

CEA - DRT/DEHT//LCB

04 38 78 34 71

Thesis supervisor :

Pascale CHENEVIER

CEA - DRF/INAC/SyMMES/STEP

04 38 78 07 21

Personal web page : http://inac.cea.fr/Pisp/pascale.chenevier/

Laboratory link : http://inac.cea.fr/symmes/

More : http://liten.cea.fr/cea-tech/liten

The lithium-ion battery (LiB) technology, used for portable electronics as well as electrical vehicles, is based on continuously changing materials to improve their energy storage capacity, life span and safety. Silicon is interesting as an active material because it can absorb up to 10 times more lithium than carbon, the usual material in the negative electrode of commercial LiB. Besides silicon can be mixed with carbon in the electrode. Only silicon in the form of nanosized particles or wires can make long-standing battery electrodes, because mechanical constraints during the charge/discharge cycles induce silicon fracturing into disconnected powder. But on the other hand, nanosized silicon offers a large surface area to surface side-reactions, leading to lithium immobilization and performance loss.

In the present PhD project, two recent CEA technologies will be associated: a method for silicon nanowire growth at large scale (patents 2014-2016), and a process for making silicon-carbon composites in which nanosized silicon is embedded in carbon microparticles. The student will be in charge of material synthesis, characterization and performance tests in LiB. In order to optimize synthesis processes and LiB life span, he/she will try to understand the reactivity of all components of the composite during LiB cycling by electronic microscopy, spectroscopy and electrochemistry.

 

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