Here is a list of Internship Training, PhDs and Post-Docs proposals. You can also refer to current Internship Training and past Internship Training.

Post-docs

• Dynamic DNA nanotechnology within microfluidic devices (Post-Doc)

Contact : A. Estevez-Torres , J.-C. Galas
Group : Nanotechnology and Microfluidic Devices (NANOFLU)
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Living cells process information and make decisions relying on chemical reaction networks that are out of thermodynamic equilibrium. Our objective is to study engineered, time-responsive networks outside of cells, in particular synthetic oscillators, using microfluidics. This research seeks to changing the paradigm in molecular computing and providing tools for building time-responsive materials. We engineer networks using a molecular toolbox reliying on short DNA strands and 3 enzymes and we design microfluidic reactors for studying the dynamics of such networks. Depending on the interests of the candidate, different topics may be explored: stochasticity effects in small volumes, behavior in an open reactor, or emergence of spatial patterns. See our project webpage for further information.


• Multiphysics Characterizations and Modelings for Cavity Nanooptomechanics and Nanoswimmers

Contact : G. Hwang , R. Braive
Group : Nanotechnology and Microfluidic Devices (NANOFLU)
            Photonics and Quantum Electronic (PEQ)
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CNRS (National Center for Scientific Research, France) invites applications for a post-doctoral researcher in micro/nanorobotic manipulations to work with Rémy Braive and Gilgueng Hwang in CNRS-LPN (Laboratory for Photonics and Nanostructures). Research will involve developing, implementing, and evaluating micro/nanorobotic manipulation systems under scanning electron microscope for characterizing electro/opto/mechanical properties of our nanomembranes and nanohelices. Candidates should have a PhD in mechanical engineering or physics related area. We are especially interested in candidates with hands on experience with micro/nanoromanipulations, electron microscopy, finite element simulations, or force sensing. For more details, http://www.lpn.cnrs.fr/fr/NANOFLU/NANOROBUST/index.php

PhDs

• Selective detection of biomolecules in complex mixtures, developing a microdevice and label free strategy based on the dynamics of interaction between a targeted protein and a ligand

Contact : C. Gosse
Group : Nanotechnology and Microfluidic Devices (NANOFLU)
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Research at the interface between microsystems and biology is today a priority at the Laboratory for Photonics and Nanostructures. We are working on the proposed subject since 2006 and our consortium involves two other teams, made of both theoreticians and experimentalists. With these physical-chemists of the Ecole Normale Supérieure and of Université Pierre et Marie Curie we were already granted on 3 national calls and we welcomed 4 PhDs. A first thermal microdevice has been produced, a technique for on-chip thermometry has been described, and first demonstration experiments on selective detection in a mixture have been published using oligonucleotides. Today, our goal is to implement this analytical strategy with real samples made of proteins. * Most often, we search for a species At by titrating it with an other species P, with which it forms a complex Ct (cf. DNA chips, Elisa tests). The other Ai species present in the sample yield Ci adducts which are less stable and thus supposed to be ‘invisible’. However it is not the case and methods based on thermodynamic discrimination reach their limits when dealing with complex mixtures (e.g. non-specific interactions induce an important background noise, selectivity is weak). In addition to the Ki equilibrium constant, each Ai + P = Ci reaction is characterized by two kinetic constants, the one related with association k+i and the one related with dissociation k-i. To emphasize one the signal coming from At and thus make it much more important than the contributions issued from the various Ai, it is in fact more relevant to use kinetic criteria than thermodynamic ones, i.e. it is advantageous to work in the 2D (k+i, k-i) space rather in the 1D Ki space.* In practice, we are using a microfabricated heater able to induce oscillations of the sample temperature T at angular frequency w, the liquid to be analyzed being contained in various microfluidic channels. The k+i and k-i rate constants also depend on T and consequently the concentrations in Ai start to oscillate. The mixture response is mainly the targeted species one when acquisition of the first harmonic signal is performed in quadrature and when w/2 = k+t = k-t. Therefore it is possible to precisely titrate At even if Ai≠t contaminants are present. A first validation has been achieved using a laboratory setup and model analytes made of DNA. * The goal of the present thesis is to demonstrate the relevance of approach for samples that are closer to real ones. We plan to determine the concentration of a protein in a complex mixture without any labeling and without reagent grafting on surfaces. The available w range will be extended up to the kilohertz to enhance the number of species that can be detected. Furthermore, biomolecules will be observed using their intrinsic UV-fluorescence, which will bypass any preliminary chemical sample treatment (i.e. any labeling reaction). A proof of principle is planed using ovalbumin, a small and well studied protein, for which ligand are numerous. * During its work the student will thus design microdevices relying on finite element model simulations and fabricate them in the laboratory clean-room. He will also perform experiments on an optical microscope equipped with all the necessary apparatus enabling both thermal excitation and fluorescence detection, he will update the setup if necessary. Finally he will select and study the biophysics of the relevant biomolecules.


• Nucleation and growth mechanisms of III-V semiconductor nanowires

Contact : F. Glas , J.-C. Harmand
Group : Elaboration and Physics of Epitaxial Structures (ELPHYSE)
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FP7 Marie Curie Actions - Initial Training Network

Job title: Doctoral Research Fellowship (PhD)

Title: Nucleation and growth mechanisms of III-V semiconductor nanowires

Location: CNRS - Laboratoire de Photonique et de Nanostructures, Marcoussis, France

Duration: 3 years

Closing date: 15 July 2013

Contacts:
Dr Frank Glas, , +33 1 6963 6079
Dr Jean-Christophe Harmand, , +33 1 6963 6081

Gross living allowance: 44 118 € per year plus mobility allowance. Salary is subject to deduction of social contributions and to taxes.

For more details read this document.




• Optical biodetection: integration of plasmonic nanostructures in nanofluidic devices.

Contact : S. Collin , A.-M. Haghiri-Gosnet
Group : Nanotechnology and Microfluidic Devices (NANOFLU)
            Physique des Dispositifs (PHYDIS)
More

Détecter des biomolécules à l’état de traces, c’est-à-dire à des concentrations inférieures au pico-molaire, dans des solutions biologiques complexes est l’un des enjeux des biopuces. Les capteurs bases sur la résonance à plasmons de surface localisés (LSPR) permettent une détection sans marquage préalable de la biomolécule cible de haute sensibilité grâce au confinement du champ électromagnétique. Ces dernières années, nous avons développé un savoir-faire aussi bien théorique qu’expérimental, qui a permis de proposer des nanostructures originales. Ces réseaux de nanoantennes sont obtenus par nanoimpression dite " douce " assistée au UV, qui permet des réplications de haute résolution sur de grandes surfaces à bas coût. Le biocapteur LSPR, qui intègre ces nanocavités plasmoniques à très faibles volumes de détection, présente une absorption quasi-parfaite (>90%) avec un haut facteur de qualité pour le mode de 2ème ordre. Nous avons ainsi obtenu une sensibilité record en indice de réfraction de 405 nm/RIU (figure de mérite >21). Nous souhaitons maintenant intégrer ce capteur de très haute sensibilité dans des dispositifs fluidiques pour des études de détection en temps réel de solutions biologiques complexes. Au cours du stage M2R, l’étudiant développera de nouvelles structures plasmoniques qu’il intègrera dans des dispositifs micro/nanofluidiques avec des chambres réduites en volume. Des simulations seront menées pour prédire les meilleures géométries des nanocavités et des canaux fluidiques. Développer des outils optofluidiques pour la détection de biomarqueurs spécifiques très faiblement concentrés est donc l’objectif majeur de ce projet. Références: [1] A. Cattoni, P. Ghenuche, A-M. Haghiri-Gosnet, D. Decanini, J. Chen, J-L. Pelouard, S. Collin, Nano Letters, 11 (2011) 3557–3563 Ce stage peut déboucher sur une thèse (financement CIFRE en cours de demande)

Internship Training

DEA/Master 2

• Plasmonics for Hot Carrier Solar Cells

Level : Master2
Contact : A. Cattoni , S. Collin
Group : Physique des Dispositifs (PHYDIS)
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In order to make photovoltaics a sustainable way to produce energy, the research community is still facing two main challenges: increase the solar cell conversion efficiency and reduce the fabrication costs. A possible solution to both these challenges may come from the emerging field of Plasmonics which provides methods for guiding and localizing light at the nanoscale (well below the scale of the wavelength of light in free space) providing for the possibility of a drastic reduction of the semiconductor material consumption and at the same time for the possibility to develop solar cells based on new concepts for higher efficiencies.

The main energy loss mechanisms in a solar cell is the rapid cooling of high-energy photo-generated carriers to the bandgap edges, through the emission of phonons. The possibility to collect photo-generated carriers before their cooling (“hot carriers”) would allow to reduce this energy loss by extraction of carriers with energies much higher than the bandgap. Slowing of carriers cooling by the so-called “phonon bottleneck effect” has been observed in bulk and quantum confined semiconductors but only under high intensities laser excitation, otherwise impossible to achieve with the sunlight. Both high optical intensities and fast extraction of hot carriers are only possible by reducing the absorption volume and the collection path to the electrodes. We have recently experimentally demonstrated the possibility to obtain the confinement of the light in a sub-wavelength volume (< λ3/1000) by using plasmonic nanocavities, fabricated over large surfaces area (1 cm²) by Nanoimprint Lithography [Cattoni et al., Nano Letters 11, 3557 (2011)]. Because the absorption is omnidirectional and independent of the polarization of the light, these structure are ideal for the design of efficient photovoltaic devices, in particular for investigating the concept of a nanoscale hot carrier solar cell.

The candidate will carry out the fabrication and the characterization of a proof-of-concept hot carrier absorber in which the a low dimensional semiconductor (thin film or nanowire) is placed inside a plasmonic nanocavity opportunely designed for multi-resonance absorption in the visible spectrum. The first task of the project will be the development an original process for the transfer of a semiconductor thin-film/nanowires-array over an host substrate. This proof-of-concept hot carrier absorber will be developed by using state of the art III-V semiconductors heterostructures grown at LPN. Full characterization of the device (spectral and angular response, photoluminescence) will allow to determine the contribution of the plasmonic structures to the temperature of the carriers. This project will be carried out at LPN in close collaboration with the IRDEP (Institut de Recherche et Développement sur l'Énergie Photovoltaïque), already partners in the “Fédération de Recherche Photovoltaïque d'Ile-de-France” and in the new “Institut photovoltaïque d’Ile-de-France”.


• Integration of blue nanoemitters for biological imaging: GaN-based active substrates for the local excitation of biomolecules

Level : Master2
Contact : A. Giacomotti
Group : Nonlinear Photonic and Quantum Information (PHOTONIQ)
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The goal of this internship is both the realization and study of nano-structured active substrates based on gallium nitride (GaN/InGaN) for the localized excitation of biomolecules, such as the green fluorescent protein (GFP). GFP is a commonly used marker in fluorescence microscopy, a major technique in biological imaging.
The integration of nano-emitters onto the surface of a substrate, together with the spatial confinement of the emission due to nanostructures, allow to locally enhance the excitation of fluorescent markers and improve the spatial resolution of the imaging technique. The proposed structures are "photonic crystals" operating at wavelengths in the visible range (λ ~ 450 nm). Specifically, periodic arrays of holes (diameter ~ 60 nm, period ~ 110 nm) etched in a GaN/InGaN thin layer on a transparent substrate will be realized.
The student will be involved both in the fabrication and the characterization of structures by scanning electron microscopy on the one hand, and their optical study through micro-photoluminescence (μ-PL) experiments on the other hand. This internship will be carried out in the framework of a collaboration between the CRHEA (design and realization of epitaxial structures) and the LPN (design, photonic crystal fabrication, optical studies). Ultimately, the active substrates will be tested on fluorescence microscopes from our biologists and biophysicists partners (M. Coppey, Institut Jacques Monod; E. Gratton, Laboratory for Fluorescence Dynamics, University of California, Irvine; L. Estrada, Quantum Electronics Lab, University of Buenos Aires). PhD thesis on this subject also possible.
Expected starting date : march/April 2013. Expected duration: 4 to 6 monthsMain contact: A. Giacomotti (LPN). Main Collaborators: S. Bouchoule (LPN), A. Cattoni (LPN) - B. Damilano (CRHEA), F. Semond (CRHEA)


• Unraveling molecular interaction dynamics by application of a thermal perturbation and collection of the intrinsic fluorescence of proteins

Level : Master2
Contact : C. Gosse
Group : Nanotechnology and Microfluidic Devices (NANOFLU)
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Consider a simple reactive system made of a biological macromolecule and of a ligand. This A + B = C system is characterized by an equilibrium constant K but also by two rate constants, one for association k+ and one for dissociation k-. Interestingly, it seems that the residence time of a drug on its target is as important as affinity. * To access chemical dynamics, the reactive system is driven out-of-equilibrium by application of a modulation of the temperature T at the frequency w. As the constants k+ and k- depend on T, concentrations also oscillate. By scanning w and by recording the amplitude and phase for the first and second harmonic we could prove that it is possible to validate the obeyed chemical mechanism and to extract the various thermokinetic parameters (K, k+, k- but also the enthalpy and the activation energies) [Gosse2011,Lemarchand2012]. Practically, to modulate the temperature of the mixture we have to analyze we make use of a microfabricated thin film resistor. Molecule concentrations are measured by epifluorescence. Several demonstrations have been performed relying on DAN strands labeled with fluorophores [Zrelli2011]. * Today we would like to study proteins and achieve detection thanks to the intrinsic fluorescence. This absence of labeling is very interesting while considering pharmaceutical screening and biodetection. * The trainee will work on the LPN experimental bench. He will study two different systems, one made of a model of toxin and of a dye that can bind it, the other one made of a therapeutic target and of potential drugs. Knowledge in photophysics and in chemical thermodynamics and kinetics will be involved. Instrumentation and microfluidic will also be slightly used. * Research will be undertaken in collaboration with Annie Lemarchand from the Laboratoire de Physique Théorique de la Matière Condensée of Université Pierre et Marie Curie and Ludovic Jullien from the Département de Chimie of the Ecole Normale Supérieure. * Opportunities to be engaged for a PhD.


• Ultra-low noise cryogenic Field-Effect Transistors

Level : Master2
Contact : Y. Jin
Group : Physique et Technologie des Nanostructures (PHYNANO)
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It is well known that most ultra-sensitive detectors such as for searching dark-matter operate at tens of mK in order to reduce their thermal noise – the fundamental noise which can only be decreased by lowering the operating temperature. Since decades, low-frequency and high impedance readout electronics are essentially based on Si JFETs with a noise benchmark of about 1nV/√Hz at 1kHz. However, due to the charge freeze-out, Si JFETs cannot operate below 100K. The use of these JFETs for amplifying signals from detectors requires thus a long cable. The cable capacitance slows the readout rate, and in addition the potential microphonic noise degrades the signals’ quality. To overcome the lack of high performance FETs (Field-Effect Transistors) for high impedance, low-power and low-frequency deep cryogenic readout electronics and to meet the needs of various experiments from space electronics to low-temperature STM, a long-term investigation was conducted at the LPN and significant progress has been realized. Research training of this proposal is flexible according to the candidate’s interest. It comprises different aspects from the material, device fabrication and characterization to the theoretical understanding. Molecular beam epitaxy and electron beam lithography will be used to realize HEMTs with different AlGaAs/GaAs heterostructures and gate configurations. Electrical and noise characterizations will be performed under cryogenic conditions. Then, noise performance for different HEMTs will be analyzed and compared in terms of the 1/f noise and white noise by taking into account different experimental parameters. Finally, the achievable lowest noise limit for each kind of HEMTs will be evaluated in-depth. This investigation will contribute to SuperCDMS project, in close collaboration with teams at Berkeley University and SLAC Stanford University, for realizing the deep cryogenic readout electronics to detect dark-matter or WIMPs (Weakly Interacting Massive Particles).


• Dual-wavelength VECSEL source at 1.55 µm for fiber-optics based sensors

Level : Master2
Contact : J.-L. Oudar , S. Bouchoule
Group : Photonic devices for telecom applications (PHOTEL)
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Temperature and strain remote sensors based on Brillouin scattering in optical fibres are presently subject to an intense scientific investigation. Their principle relies upon the spectral and temporal analysis of the Brillouin Stokes wave, backscattered all along the fibre from an injected optical pulse of high spectral purity. This analysis and measurement is currently done in the radiofrequency domain around 10 GHz. The objective of the research project is to study a novel solution better suited to a low-cost implementation, relying upon a measurement of the Brillouin shift at lower frequencies (<1GHz), thanks to optical heterodyning. This can be achieved through the development of a dual-frequency laser source, with a frequency difference close to the magnitude of the Brillouin shift. The advantage of using a single laser source in this context is that the beat note at the frequency difference is intrinsically more stable than the optical carrier frequency of each lasing line. During the internship, the student will participate to the development of a dual-frequency laser source of the VECSEL type emitting at 1.55 µm. This work will benefit from the technological development of efficient 1.55 µm VECSELs performed at LPN. Besides a theoretical (design) work required for obtaining adequate characteristics from the laser source, the essential part of the work will be experimental (participation to the fabrication of VECSELs in the clean room, assembling a first prototype of the dual frequency laser cavity). On this project it will be possible to go on with a thesis work, on the development of dual-frequency VECSELs at 1.55µm and their use for the detection of Brillouin signals via optical heterodyning, in collaboration with IFSTTAR and ANDRA. Expected starting date: March 2013– Contact jean-louis.oudar@lpn.cnrs.fr


• Fast detection of pathogenic agents: nanofluidic devices for selective pre-concentration. (Master)

Level : Master2
Contact : A.-M. Haghiri-Gosnet
Group : Nanotechnology and Microfluidic Devices (NANOFLU)
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One of the most challenging problems in immunoassays is to detect low abundance analytes in complex samples. If filtration through nanoporous membrane was first proposed as an efficient preconcentrator, recent theoretical studies1-2 of perm-selective transport through nanochannel have predicted high rate of pre-concentration (up to 103). In this context nanofluidics appears as a very promising route for studying the preconcentration of pathogenic agents in the field of bio-risk. During the last 4 years, our group has developed a double theoretical and experimental expertise on the mechanisms of preconcentration in such a nanofluidic device. Based on an original process in pure glass chip3, selective preconcentration can be monitored to spatially isolate the low abundant protein in the anodic chamber. One top view of the nanoslit device is shown in the figure where the location of preconcentration corresponds to the fluorescent point. Further work is now needed to implement such demonstrator in a more applicative biochip that has to be adapted for multiplex detection of complex samples. The Master/PhD work will focus on the development of new nanofluidic preconcentrator devices for a multiplex detection of pathogenic agents (such as ovalbumine for the threat of toxins). To modulate the volumic surface charge (VSC)2 different geometries for the selective nanofilter will be studied: (1) integration of polarisable electrode and (2) integration of original nanostructures by 3D Lithography. Simulations1-2 will be performed to study and predict the electrokinetic transport under high field and hydrodynamic pressure. Developing fast sensitive analytic methods for the detection of “fluorescent antibodies/bioagents of the threat” is our main goal. The final direction of this work will strongly depend on the candidate's ambitions. This work is financial supported by French army (DGA). Acquired skills: This is a highly multidisciplinary research topic at the interface between physics, analytical chemistry and biology. You will work with people skilled in these three disciplines including the 3rd year PhD (A-C Louër) engaged on this subject. At the end of your PhD, you should have acquired a large experience in microfluidics (fluorescent microscopy, numerical simulations) with a specific know-how on micro- and nanofabrication processes in a clean room environment.


• Optical biodetection: integration of plasmonic nanostructures in nanofluidic devices (Master)

Level : Master2
Contact : S. Collin , A.-M. Haghiri-Gosnet
Group : Nanotechnology and Microfluidic Devices (NANOFLU)
            Physique des Dispositifs (PHYDIS)
More

Détecter des biomolécules à l’état de traces, c’est-à-dire à des concentrations inférieures au pico-molaire, dans des solutions biologiques complexes est l’un des enjeux des biopuces. Les capteurs bases sur la résonance à plasmons de surface localisés (LSPR) permettent une détection sans marquage préalable de la biomolécule cible de haute sensibilité grâce au confinement du champ électromagnétique. Ces dernières années, nous avons développé un savoir-faire aussi bien théorique qu’expérimental, qui a permis de proposer des nanostructures originales. Ces réseaux de nanoantennes sont obtenus par nanoimpression dite « douce » assistée au UV, qui permet des réplications de haute résolution sur de grandes surfaces à bas coût. Le biocapteur LSPR, qui intègre ces nanocavités plasmoniques à très faibles volumes de détection, présente une absorption quasi-parfaite (>90%) avec un haut facteur de qualité pour le mode de 2ème ordre. Nous avons ainsi obtenu une sensibilité record en indice de réfraction de 405 nm/RIU (figure de mérite >21). Nous souhaitons maintenant intégrer ce capteur de très haute sensibilité dans des dispositifs fluidiques pour des études de détection en temps réel de solutions biologiques complexes. Au cours du stage M2R, l’étudiant développera de nouvelles structures plasmoniques qu’il intègrera dans des dispositifs micro/nanofluidiques avec des chambres réduites en volume. Des simulations seront menées pour prédire les meilleures géométries des nanocavités et des canaux fluidiques. Développer des outils optofluidiques pour la détection de biomarqueurs spécifiques très faiblement concentrés est donc l’objectif majeur de ce projet. Références: [1] A. Cattoni, P. Ghenuche, A-M. Haghiri-Gosnet, D. Decanini, J. Chen, J-L. Pelouard, S. Collin, Nano Letters, 11 (2011) 3557–3563 Ce stage peut déboucher sur une thèse (financement CIFRE en cours de demande)


• Toward controlled swimming of artificial bacteria based on helical nanobelts for microfluidic applications

Level : Master2
Contact : G. Hwang
Group : Nanotechnology and Microfluidic Devices (NANOFLU)
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Swimming micro/nano agents at low Reynolds number could open new biomanipulation tools for biomedical applications. However it is challenging due to the increased viscosity of liquid. To propose controlled nanoswimmers which can overcome this low Reynolds dynamics, the study of biomimetic nanoswimmers based on InGaAs/GaAs helical nanobelts (HNBs) was initiated in April 2009. We fabricated and more recently achieved controlled nanohelices swimming in the liquid using both electro-osmotic and electromagnetic force. Concerning the swimming performance, the HNBs could swim in the velocity of 24 times of their body lengths per second which even surfasses the performance of nature's bacteria propulsion (e. g. E. coli bacteria 5-10 times of body length per second). The high-speed camera analyses at the the frame rate of 342 fps further revealed the discontinuous swimming propulsion. It implies that passive motions such as compression and rotation of HNBs can reduce viscous drag during their swimming. It is also proved that surface coating of HNBs could enhance the swimming performances by improving hydrodynamic interaction. External electromagnetic field could enhance their manueverability by adding active rotation and/or oscillation. This particularly interesting result opens the way for a variety applications which require fast swimming performance at low Reynolds number liquid medium. From our experiences, experiments under open channels pose difficulties of their swimming performance characterizations due to the non-controlled environmental parameters. The controlled environment with the channel surface should be incorporated to observe and characterize the HNB swimming propulsions. The subject of this stage is the study of the swimming performances in microfluidic chamber with electromagnetic field. This approach should allow us to control the environment and simulate the swimming propulsion through blood vessels in vivo biomedical applications. This approach requires much technological steps especially in particular the use of soft lithography to define microfluidic channels with different geometries. Different geometries and designs of microfluidic chips will be fabricated to study the swimming behaviors of HNBs through the closed channels. Then the optimal (minimized the surface effect) dimension of the microfluidic chanels for HNBs will be applied to characterize the pure hydrodynamic contribution by active oscillations and/or rotations. We eventually intend to develope microfluidic chips consisting of single or multiple HNBs as nanoswimmers for the remotely controlled biomanipulation tools. For more details, http://www.lpn.cnrs.fr/fr/NANOFLU/Nomad.php

Master 1

• Development of closed-loop control for a Microswimmer in Microfluidics

Level : Master1
Contact : G. Hwang
Group : Nanotechnology and Microfluidic Devices (NANOFLU)
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Cargo transport microrobotic swimmers inside micro?uidic channels could become useful tools for wide applications for biology and transducers technology, though their swimming performances are largely limited by low Reynolds number dynamics and surface phenomenon perturbations from the con?ned fluidic environments. Working on new mobile microrobotic swimmers has shown outstanding dynamic performances and simple process for several different designs and we now aim to develop a closed-loop manipulation strategy, involving fast-framerate camera and electromagnetic generator (4-8 axis generating signals up to 5 kHz). Automated in-plane trajectories are now a major challenge in our community and it has become a yearly event at ICRA, one of the major conferences in robotics. It will be held this year on May 6-10 in Karlsruhe, Germany. Winning in 2009 and 2010 the speed contest, this conference is now the opportunity to develop the controllability part of our setup. LPN facilities include a whole clean room complex allowing us to run in parallel our process and the characterization and experimentation on our test-bench. With more than a hundred people from different background, LPN provides an international context with rare resources and diversity, with fields from quantum physics to biology. It would constitute an excellent first experience in academic research. Expected work: The student will have to achieve the following tasks: • Getting in touch with the setup, software and physics: - Short bibliography - Comparing current real-time tracking performances to post-treatment with Tracker soft - Eventual update of the algorithm on our C# program using Visual Studio IDE • Implementation of closed-loop control - Definition of the model and parameters of the PID control - Implementation and analysis of performance in post-treatment - Define a tuning protocole, and if possible, an algorithm Depending on how the project evolves, different perspective could be planned such as the adaptation of the closed loop control to a haptic interface for smooth control and precise micromanipulation. Publications are highly desired on this project. The student will work with Hugo Salmon (2nd year Ph.D student). Website: http://www.lpn.cnrs.fr/fr/NANOFLU/Nomad.php

DUT

• Détermination de propriétés physiques de dépôts de couches minces diélectriques (Avril-Juin 2013)

Level : DUT
Contact : X. Lafosse
Group : Service de Technologie (TECHNO)
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L’objet de ce stage de 3 mois porte sur la détermination de caractéristiques physiques sur des dépôts de matériaux diélectriques (Oxydes, nitrures..), en couches minces, usuels, effectués au laboratoire. Ces matériaux sont principalement utilisés pour leurs propriétés isolantes (passivation, grille), mécaniques (cantilever, micro-membranes) ou optiques (filtres miroirs ou antireflets). Les dépôts en couches minces diélectriques sont réalisés, au laboratoire, par différentes techniques principalement situées en salle blanche : Pulvérisation cathodique, évaporation assistée par ions, PECVD, oxydation thermique du Silicium. Un certain nombre de matériaux déposés par ces techniques nécessitent des caractérisations complémentaires afin d’évaluer leur qualité pour les applications internes ou demandes externes au laboratoire. Typiquement, seront elaborés et mesurés lors de ce stage, plusieurs types de dépôts de matériaux tels que le SiO2, Si3N4, TiO2 et HfO2. Ces matériaux seront déposés soit par pulvérisation cathodique radiofréquence magnétron ou par évaporation assistée par ions. Les caractérisations qui seront menées sur les échantillons permettront de mesurer : - Les rugosités RMS (par Microscopie à Force Atomique - Les contraintes mécaniques (par Profilométrie mécanique - Les indices optiques (par Ellipsométrie Spectroscopique - Les permittivités relatives εr (par la réalisation d’une capacité en couche mince, Mesure C(V) et microscopie optique - Quelques observations par Microscopie électronique à Balayage seront menées pour étoffer l’étude et y apporter un volet « Structural ».

Nous ferons varier plusieurs paramètres de dépôt de ces couches afin d’en mesurer l’impact sur les caractéristiques précitées.

Outre les dépôts de couches minces et les caractérisations, le/la stagiaire sera potentiellement amené à utiliser d’autres techniques d’élaboration / mise en forme de couches minces comme la photolithographie ainsi que la gravure sèche (RIE). Les informations qui seront obtenues permettront de faire évoluer certains procédés afin d’obtenir les couches et revêtements les plus adaptés en fonction des demandes. Ce travail se deroulera essentiellement en Salle Blanche.