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  • 13

    08/2018

    Hung-Ling Chen, PhD Student at C2N, rewarded with Best Student Paper Award at the WCPEC-7 conference


      Andrea Cattoni.

    Hung-Ling Chen, PhD Student at C2N (Sunlit team), received the Best Student Paper Award for Area 1 (Fundamental Conversion Mechanisms) at the 7th World Conference on Photovoltaic Energy Conversion for his work “19.9% efficient ultrathin GaAs solar cells with nanostructured back mirror formulti-resonant absorption and enhanced luminescence extraction”.

    This Best Student Paper Award recognizes outstanding work by students in each technical area. In addition to judging the technical content of the student’s work, oral presentations and the student’s role in the work are assessed. One “Best Student Paper Award” is given out for each technical area of the WCPEC-7.


  • 27

    07/2018

    New opportunities in k-space optical microscopy


      Bernard Bartenlian.

    News from the Institute of Molecular Sciences of Orsay - July 25, 2018 (released in French)

    Researchers from ISMO and C2N publish the first comprehensive study of the effects and artifacts that form the image in optical microscopy of the Fourier plane, on periodic samples. These artifacts, used to exceed the diffraction limit, can be exploited, for example, for nano-positioning and autofocus applications in light microscopy. This work is published in the Journal of Applied Physics and the article is briefly featured on the AIP Scilight website.

    k-space optical microscopy (or Fourier-plane imaging) is a technique increasingly used in all fields of photonics including biosensing, photonic crystals, plasmonics, and single-molecule studies. It consists in the imaging of the back focal plane of a microscope objective ("k" refers to the coordinates in Fourier space). However, the performance of this technique under various illumination conditions, as well as its artifacts and the ways to overcome or even benefit from these artifacts, have rarely been addressed in the literature.

    In this article, a group from the Institute of Molecular Sciences of Orsay - ISMO (CNRS/UPSUD) and a group from the Center for Nanoscience and Nanotechnology – C2N (CNRS/UPSUD) jointly provided a detailed description of the performance and inherent artifacts of k-space optical microscopy for the study of periodic nanoparticle arrays. They used the various illumination configurations available on an inverted optical microscope, i.e., with transmitted or reflected, collimated or focused, coherent or incoherent light. The aim of this work is to help readers exploit the full potential of this technique and to foster the development of innovative applications.

    Among the most interesting results are images of k-space optical microscopy of periodic samples illuminated in reflection with a focused laser beam. These images result from the interference of the reflected and diffracted light beams. Crucial information contained in the phase of the field, which can be related either to the geometry of the sample or to the relative position of the focal point and the sample, are thus converted into intensity variations. This can be used for the accurate control of the sample position in optical microscopy, with a precision well beyond the diffraction limit of light. Possible technological spin-offs of these results include applications to autofocus and repositioning in optical devices, e.g., in writing and readout operations for optical data storage.

    Source : k-space optical microscopy of nanoparticle arrays: opportunities and artifacts,” Jean-François Bryche, Grégory Barbillon, Bernard Bartenlian, Gérald Dujardin, Elizabeth Boer-Duchemin, Eric Le Moal, Journal of Applied Physics (2018).

    Contact :

    • Eric Le Moal, Institut des Sciences Moléculaires d’Orsay (CNRS - Université Paris-Sud)
    • Bernard Bartenlian, CNRS researcher at C2N
    • Jean-François Bryche, PhD student at C2N

  • 6

    07/2018

    Quandela, a spin-off of CNRS, received a "Grand prix i-LAB 2018"


      Pascale Senellart.

    The start-up Quandela, co-founded by Valérian Giesz, Niccolo Somaschi and Pascale Senellart, CNRS Senior Researcher, received one of the 14 Grands Prix of the French national competition to support the creation of innovative technology companies "i-LAB 2018" from the hands of Frédérique Vidal, French Minister of Higher Education and Research.

    Based on a lithography technique developed at the Centre de nanosciences et de nanotechnologies – C2N (CNRS/Université Paris-Sud), Quandela manufactures and delivers sources of light delivering a single photon in each pulse. These sources of light, which operate at a cryogenic temperature, have the advantage of emitting single photons with very high efficiency and with identical characteristics, making them a tool of choice for researchers of quantum photonics in academia and industry, and more broadly for research in quantum physics.

    As a result of fundamental research of the highest level conducted for many years by Pascale Senellart, laureate of a CNRS silver medal in 2014, Quandela's singlephoton source technology now follows a robust and reproducible manufacturing process. This was made possible in particular by the prematuration program of CNRS and the Labex Nanosaclay in 2016, before the creation of Quandela in 2017. In June 2018, Quandela successfully installed a first  single photon source at the University of Brisbane in Australia.

    The Grand Prix i-Lab is ​​accompanied by significant financial support. This grant will allow Quandela to develop a new range of turnkey sources that are easier to use and to initiate their industrialization.

     

    The jury of the "I-Lab 2018", chaired by Ludovic Le Moan, General Director of Sigfox, distinguished 64 winners among 383 applications received. Among them, 14 Grands Prix reward the most outstanding projects, which are part of one of the ten societal challenges defined by the agenda France Europe 2020.

    For the first time, the Grands Prix will be accompanied by a mentor, a seasoned entrepreneur who will help them face a major challenge in their development, such as the completion of a first fundraising event or the introduction of their product on the market. Pierre Barnabé, Senior Vice President Big Data and Security at Atos France, has agreed to be the mentor of Quandela, inaugurating a rapprochement between the two companies around quantum information technologies.

     


  • 5

    07/2018

    Delphine Marris-Morini rewarded with a Fabry - de Gramont prize 2017 from the French Society of Optics (SFO)


      Service communication.

    Delphine Marris-Morini, Professor of University Paris-Sud at C2N, was rewarded with the Fabry - de Gramont prize 2017 from the French Society of Optics (SFO) during the Optique Toulouse 2018 conference.

    The prize rewards a young researcher (below 40), internationally recognized, whose research works have been noteworthy for their quality, originality and potential impact.

    Delphine Marris-Morini was rewarded for her works in the field of photonic on silicon, integrated optoelectronic devices, optical propreties of quantum well heterostructures and integrated photonic circuits in mid-infrared.


  • 18

    06/2018

    Beyond a material’s limit of conductance by controlling the interactions between electrons


      Frédéric Pierre.

    News from Institut de physique of CNRS - June 15, 2018 (released in French)

    Physicists have observed that the conductance of an electrical current can go beyond its theoretical quantum limit, by exploiting the correlations developing in the vicinity of a quantum phase transition.

    How high can the electrical conductance be? In contrast to resistance, this quantity measures the ease with which current flows. In fundamental physics, conductance is a very important characterization tool. In electronic chips, increasing the conductance of interconnects would reduce heating that limits performance.

    The standard theory of quantum transport, however, predicts an upper limit for conductance, even in the absence of defects. This limitation reflects the fact that electrons crossing a narrow conductor must pass one after the other, each with a minimal extension imposed by quantum mechanics. However, when the interactions are very strong, the electrons can no longer be considered separately. They are then in an intermediate state, between free electrons and superconductivity. The limit can then be exceeded by a collective effect between the electrons, similar to that of a viscous behavior of an electronic fluid. This phenomenon has just been observed in graphene at the University of Manchester.

    Researchers have now also observed it in a quantum circuit where the magnitude of the overshoot of the standard conductance limit, as well as the temperature range where it occurs, can be controlled in situ. To do this, physicists at the Centre de nanosciences et de nanotechnologies/Centre for Nanoscience and Nanotechnology - C2N (CNRS / UPSud / Univ Paris Diderot), in collaboration with theoreticians at the University College Dublin, University of Paris-Sud and University of Paris Diderot, are exploiting the electronic correlations that develop in the vicinity of a quantum phase transition, and which occur at a few thousandths of degrees above absolute zero.

    At the heart of the quantum circuit is a metal island tuned so that the increase of its charge by an electron does not change its energy. This is fundamental, because then the system will not be frozen in one of these two states (with or without an additional electron charge), even at the lowest temperatures. In the contrary case, the system would freeze in the state of lower energy and one would lose this degree of freedom of a charge addition. However, it is the coupling of this charge with the electrons entering and leaving the island by three small individually adjustable contacts that generates strong correlations between these electrons, and which leads to the appearance of a quantum phase transition. The very existence and magnitude of the overshoot of the standard conductance limit is then controlled by the degree of symmetry between the different contacts.

    This work published in the journal Science opens a research path for low-power electronics. The implemented device has no applications but is a model study system. More generally, this work is part of the exploration of a wide variety of unconventional phenomena associated with quantum phase transitions.

    Figure: Evolution of the conductances of 3 quantum contacts connected in parallel to a small metal island as a function of the temperature. Each colored arrow represents the variation of the conductance G2 of one of the contacts as a function of the conductance of the other two contacts (set such as G1 = G3) when the temperature varies from 55 mK to 8 mK for different initial configurations. The conductance G2 exceeds the quantum limit e2 / h (e is the charge of the electron and h the Planck constant) in the gray zone due to strong electronic correlations. The gray lines represent the theoretical predictions (NRG) for a very small asymmetry. © C2N, CNRS/UPSud/Univ. Paris Diderot

     

    Reference
    Tunable quantum criticality and super-ballistic transport in a “charge” Kondo circuit
    Z. Iftikhar, A. Anthore, A. K. Mitchell, F. D. Parmentier, U. Gennser, A. Ouerghi, A. Cavanna, C. Mora, P. Simon, F. Pierre
    Science (2018), doi:10.1126/science.aan5592

    • Read the article on ArXiv

     

    -    Centre de nanosciences et de nanotechnologies - C2N (CNRS/Université Paris-Sud-Université Paris-Saclay)
    -    Laboratoire Pierre Aigrain – LPA (CNRS/ENS Paris/Univ. Paris Diderot/Sorbonne Université)
    -    Laboratoire de physique des solides – LPS (CNRS/Univ. Paris-Sud)
    -    University College Dublin, Irlande

     

    Contact

    Frédéric Pierre, CNRS senior researcher


  • 13

    06/2018

    Olivier Dalstein, PhD Student at C2N, rewarded with a 2018 thesis prize from the Société Chimique de France


      Andrea Cattoni.

    6 thesis prizes have been attributed to young researchers during the event "Journée des Jeunes Talents de la Chimie en Ile-de-France", organised on 4th June 2018 by the Ile-de-France office of the Société Chimique de France/French Society of Chemistry (SCF), in order to reward the excellence of their work.

    Olivier Dalstein, who was a PhD Student from 2014 to 2017 at the Laboratoire de Chimie de la Matière Condensée de Paris - LCMCP (CNRS/Sorbonne Université/Collège de France) and at the Centre de Nanosciences et de Nanotechnologies / Centre for Nanoscience and Nanotechnology - C2N (CNRS/Univ. Paris-Sud) with Andrea Cattoni, was rewarded with the industrial prize, sponsored by the company Ynsect.

    The aim of his thesis, entitled « Nanoporous thin films structured by Top-Down & Bottom-Up approaches: towards smartphone-compatible optical sensors », was to apply micro/nano-fabrication techniques (Soft Nanoimprint Lithography, Crack-Patterning…) to original nanoporous materials (MOF, sol-gel) in order to fabricate photonic sensors used for the detection of atmospheric pollutants like VOC. The optical responses of the fabricated structures (e.g. diffraction gratings) were measured directly with a CCD from a camera or a smartphone. This work led to 4 publications and an international patent.


  • 25

    05/2018

    Studying thin magnetic layers using an analogy with the physics of soap bubbles


      Nicolas Vernier.

    Physicists have studied thin films of magnetic material and applied concepts of the physics of soap bubbles. With this approach, which had been barely used so far, they were able to explain new phenomena.

    There is a very interesting analogy between the physics of magnetic thin films and those of soap bubbles: in both cases, it is possible to think in terms of interfaces, in terms of energy associated with the surface area of these interfaces, and in terms of difference of pressure on both sides of an interface. In thin film physics, the soap film is replaced by the magnetic domain wall, which separates two areas in which the magnetization is uniform. The pressure of the gas contained in the soap bubbles is replaced by the action of the applied magnetic field (B), which creates a difference of pressure (with a value equal to 2MB, where M is the magnetization density). These basic concepts were used by the soap bubble specialists and allowed the researchers to explain in a simple way many properties observed so far. In the case of magnetic thin films, despite its strengths, this approach had been barely used so far.

    Researchers from the Centre de Nanosciences et de Nanotechnologies/Centre for Nanoscience and Nanotechnology - C2N (CNRS / Paris University), in collaboration with Beihang University in China and the Spintec laboratory (CEA/CNRS/Univ Grenoble Alpes), have observed phenomena similar to those known for soap bubbles in ultra-soft films of CoFeB, and they could demonstrate the soap bubble analogy. To begin, they found that magnetic domains of semicircular shape were not stable without a field. This first effect is explained by the Laplace pressure induced by the curvature of the domain wall, which tends to reduce the radius of the semicircular domain it delimits. By determining the external field that must be applied to stabilize the domain, they were able to determine the interfacial tension energy associated with the domain wall. They were also able to observe the repulsion between two domains almost in contact: in a way totally analogous to the classical experience of soap bubbles in contact, where the big bubble "eats" the little one, the big domain crushes the little one. Their work was published in the journal Physical Review Applied.

    With the approach adopted here they could also explain a very common magnetic domain wall pinning phenomenon, which occurs at an abrupt widening of the nanowire section. This trapping is explained by the interfacial tension force applied at the enlargement, which tends to hold the wall and must be overcome. The measurement of the field required to depin appears as a second method to directly measure the interfacial wall energy. This energy is a very important parameter, but remains to access because the potential experiments to measure it are likely to be distorted by formidable artifacts, which means artificial signals related to the experimental method which cause an error of analysis. The current experiments offer at last a reliable measurement method, with a simple and intuitive understanding of the phenomena.

    Figure : Kerr images (dark parts correspond to the reversed magnetization area) showing the spontaneous collapse of the half bubble after its creation using a pulse of magnetic field applied at time t=0. The time of acquiring for each picture is given at the top left of each picture. After the field pulse, during all this process, the magnetic field was zero. From X. Zhang - C2N (CNRS/Univ. Paris-Sud)
     

    Reference:
    Direct Observation of Domain-Wall Surface Tension by Deflating or Inflating a Magnetic Bubble
    X. Zhang, N. Vernier, W. Zhao, H. Yu, L. Vila, Y. Zhang and D. Ravelosona
    Physical Review Applied (2018)

    DOI: doi:10.1103/PhysRevApplied.9.024032

    - Centre de Nanosciences et de Nanotechnologies – C2N (CNRS/Université Paris-Sud/Université Paris Diderot)
    - Fert Beijing Institute, School of Electronic and Information Engineering, Beihang University, China
    - Unité Spintronique et technologie des composants - SPINTEC (CEA/CNRS/Université Grenoble Alpes)

    Contact :

    - Nicolas Vernier, Associate Professor Université Paris-Sud at C2N


  • 22

    05/2018

    Pascale Senellart-Mardon is elected as a Fellow Member 2018 of the Optical Society of America


      Service communication.

    Pascale Senellart-Mardon, CNRS senior researcher at C2N, was elected as a Fellow Member 2018 of the Optical Society of America (OSA) during the CLEO conference about laser science and their applications in photonics, that took place in May 2018 at San Jose, California.

    She was elected “for inventing in-situ optical lithography that couples quantum dots and optical cavities with nanometric precision, realising solid-state single and entangled photon sources of unsurpassed performance that are moving quantum optics towards a scalable future”.

    Photo : Pascale Senellart-Mardon elected as Fellow Member 2018 by Ursula Gibson, OSA President-Elect © OSA

  • 15

    05/2018

    "Super-thermal" emission of photons by coupled nanolasers


      Alejandro M. Yacomotti.

    News from Institut de physique of CNRS - April 27, 2018 (released in French)

    Thanks to two coupled nanolasers, physicists were able to generate an out-of-equilibrium system emitting multi-photon bursts, known as "super-thermal" light. This approach is not restricted to lasers but it can be extended to other nanoscale systems.

    Due to their small size, nanolasers have remarkable properties, including low power consumption and small footprint. They are the subject of intense research aiming at various applications, from telecommunications to quantum information. By coupling them in a compact way, it is possible to tailor the statistics of the emitted photons, producing in particular « extra noise » or « extra correlations », which is an asset for applications such as the non-linear energy conversion, the "ghost" imaging that is developed for astrophysics and the quantum information.

    When the coupling between the nanolasers is weak, the emission of each laser can be well distinguished. But if the coupling is strong enough, the photons get distributed between the two hybrid modes, and become quite insensitive to perturbations. It is the energy exchange between these modes that is studied here, when the system is excited by light pulses shorter than the electronic characteristic times involved. Such excitation places the system out of equilibrium. One of these modes behaves as a « conventional laser » mode and it is subjected to small fluctuations, while the other one undergoes a particular noisy regime. It emits flashes of photons with a so-called "super-thermal" statistics: the photons are not emitted one by one or randomly –in the sense of Poisson– , but in the form of bursts where the quanta are concentrated in short times. This demonstration was made possible thanks to an original set-up enabling the measurement of the complete statistics of the emitted photons, in spite of the very short times in play. Researchers are now aiming to mold the statistics with very few photons, in the quantum regime.

    This approach does not require the engineering of special emitters or the interaction between modes, as it has been implemented so far. Such a “generic route”, obtained by driving the system far-from-equilibrium through a rapid variation of a parameter or « quench », can be transposed to many other systems. This is for instance the case of Brownian motion experiments applied to suspended pollen. In this analogy, the pollen grains and their potential energy can be mapped to photonic states. The system gets out of equilibrium due to a sudden drop in temperature. It can therefore be observed that grain distribution in the space/time also follows a "super-thermal" statistics.

    The nascent study of out-of-equilibrium statistics in nanoscale, low photon number systems is particularly promising. This work, published in the journal Physical Review X by a team of physicists from the Centre de Nanosciences et de Nanotechnologies - C2N (CNRS / Université Paris-Sud) was produced in collaboration with the University of the Balearic Islands.

    Figure : Simulated response of coupled nanolasers under excitation of a short pulse showing the distribution of the population difference between the modes and more generally the distribution of the optical field. © A. M. Yacomotti, C2N (CNRS/Univ. Paris-Sud)
     

    Reference:
    Far-from-equilibrium route to superthermal light in bimodal nanolasers
    M. Marconi, J. Javaloyes, P. Hamel, F. Raineri, A. Levenson and A. M. Yacomotti
    Physical review X (2018)

    DOI: doi.org/10.1103/PhysRevX.8.011013

    -    Centre de Nanosciences et de Nanotechnologies – C2N (CNRS/Université Paris-Sud/Université Paris Diderot)
    -    Departament de Física, Universitat de les illes Balears, Spain

    Contact:

    -    Alejandro M. Yacomotti, CNRS researcher


  • 11

    05/2018

    C2N's participation at the Nano, Micro, and Opto-Electronic Days (JNMO)


      Service Communication.

    From Wednesday 13th to Friday 15th of June will be held at Cap Esterel-Agay the 16th JNMO (Nano, Micro, and Opto-Electronic Days) organized by the CRHEA - Research Center on Hetero-epitaxy and its Applications.

    With more than 30 years of existence these days bring together, every two years, the French scientific community concerned by the development, physics and integration of components and nanodevices whose main purpose is microelectronics or optoelectronics. The scientific fields covered are broad, ranging from the fundamental study of the material and the nanostructures to that of the components and their integration into the systems, with particular emphasis on the following topics:

    • Micro-nano-technologies and systems
    • New materials and nanostructures
    • Structural, optical and electrical characterization of semiconductors
    • Physics of low dimensionality structures
    • Micro and nanophotonics, photonic crystals, metamaterials, plasmonics
    • Photonic components, photonic and optoelectronic integration
    • Electronic components and micro-nano-electronic integration
    • THz components and technologies

    The thematic diversity that is approached offers a wide choice of presentations such as on "nanolasers semiconductors and their applications" Fabrice Raineri ( Associate Professor Université Paris Diderot at C2N) or on the growth of nanowires III-V observed in real time with the atomic resolution "of Jean-Christophe Harmand (Research Director CNRS at C2N) but also opportunity representativeness within the scientific committee where will be present number of members of C2N including Frédéric Aniel (Professor University Paris-Sud), Jean-Luc Pelouard (CNRS Research Director) and Isabelle Sagnes (CNRS Research Director). Deadline for abstracts: May 15, 2018. Learn more: http://www.crhea.cnrs.fr/jnmo2018/inscriptions.htm


  • 4

    05/2018

    A new memory resistive device developed with magnetic nanopillars surrounded by resistive silicon switches


      Dafiné Ravelosona.

    Magnetic nanopillars surrounded by resistive silicon filaments have been used to develop a novel memristive memory.

    Emerging non-volatile memories (NVMs) combined with novel computing architectures have recently been considered as the most promising solution to overcome the “memory wall” of von Neumann computing systems. For instance, in-memory computing architectures based on closely integrating fast NVMs with logic functions have been proposed to minimize the power consumption and pave the way toward normally-off/ instant-on computing. Along this direction, two of the most promising NVMs, i.e., magnetic random access memory (MRAM) and resistive random access memory RRAM have attracted increasing interest, but each of them still shows a few shortcomings.

    A collaboration between the Centre de Nanosciences et de Nanotechnologies/Centre for Nanoscience and Nanotechnology – C2N (CNRS/Université Paris-Sud) and Beihang University in China demonstrates a novel memory resistive (“memristive”) device combining the advantages of MRAM and RRAM in a single element. It is based on a magnetic tunnel junction nanopillar surrounded by resistive silicon filaments. It features spin transfer torque fast switching for computation together with multilevel resistive switching for non‐volatile memory. Their work is published in the magazine Advanced Electronic Materials and is used as a cover of the March 2018 issue.

    This work provides new functionalities that are inaccessible to conventional NVMs, e.g., for in-memory computing and neuromorphic computing as non-von Neumann computing architectures.

    Figure : This works was published in Advanced Electronic Materials (volume 4, issue 3, March 2018) and was chosen as cover picture.
     

    Reference:
    Memristors: Heterogeneous Memristive Devices Enabled by Magnetic Tunnel Junction Nanopillars Surrounded by Resistive Silicon Switches,
    Y. Zhang, X. Lin, J.-P. Adam, G. Agnus, W. Kang, W. Cai, J.-R. Coudevylle, N. Isac, J. Yang, H. Yang, K. Cao, H. Cui Deming Zhang, Y. Zhang, C. Zhao, W. Zhao, D. Ravelosona, Advanced Electronic Materials (2018)
    DOI: https://doi.org/10.1002/aelm.201870014  

    -    Centre de Nanosciences et de Nanotechnologies – C2N (CNRS/Université Paris-Sud)
    -    Fert Beijing Institute, Beihang University - Beijing, China
    -    Institute of Microelectronics, Chinese Academy of Sciences - Beijing, China

    Contact :

    -    Dafiné Ravelosona, Senior CNRS researcher at C2N


  • 23

    04/2018

    Taking a step towards intelligent miniature chips


      Damien Querlioz.

    CNRS Press Release − April 18, 2018

    Researchers from the Unité Mixte de Physique CNRS/Thales and the Centre de Nanosciences et de Nanotechnologies - C2N (CNRS/Université Paris-Sud), in collaboration with Japanese scientists, have developed a new type of sensory nano-neuron. This time1 it uses the properties of superparamagnetism2 to better mimic the properties of the sensory parts of the nervous system. The researchers used neuron assemblies for inspiration. Those can propagate learning to a larger population when they are taught to do something. Once functions are implemented, the nano-neurons can, for example, decode them and if need be reproduce cursive letters. This innovation in the domain of nanotechnologies draws inspiration from neuroscience by imitating strategies used by the visual and motor cortices. Eventually, the researchers plan to assemble, in collaboration with other laboratories, several types of nano-neurons and nano-synapses to create a single neuromorphic network, a future artificial nervous system that would involve the team developing ever more complex networks uniting sensory functions (sight, touch, etc.) and use less energy than current computers.

    This article was published on April 18, 2018 in Nature Communications.

    1 Press release “Le premier nano-neurone capable de reconnaissance vocale voit le jour” - September 19, 2017
    2 Nano-magnets which, because they are so small, exhibit an unstable, random nature

     

    Reference
    « Neural-like computing with populations of superparamagnetic basis functions » Alice Mizraahi, Tifenn Hirtzlin, Akio Fukushima, Hitoshi Kubota, Shinji Yuasa, Julie Grollier, Damien Querlioz

    Contacts
    Damien Querlioz |  (+33) 1 69 15 33 58 | Centre de nanosciences et de nanotechnologies (CNRS/Université Paris-Sud)
    Julie Grollier | +33 (0)1 69 41 58 61 | Unité mixte de physique CNRS/Thales

    Juliette Dunglas | +33 (0)1 44 96 46 34 | Press CNRS

     


  • 23

    04/2018

    Topological acoustics at the nanoscale


      Daniel Lanzillotti Kimura.

    Nanometric semiconductor structures have been used to confine ultrahigh frequency sound by exploiting their topological properties.

    The 2016 Nobel Prize in Physics was awarded to the field of topological matter. A key result was the demonstration that topology can be used to predict the behavior of solids. An example is the trapping of electrons at the interface between two topologically different crystalline insulators. Recently, similar phenomena have been observed in optics and macroscopic acoustics.

    Researchers from the Centre de Nanosciences et de Nanotechnologies/Centre for Nanoscience and Nanotechnology – C2N (CNRS/Université Paris-Sud) and the laboratory Matériaux et Phénomènes Quantiques – MPQ (CNRS/Université Paris Diderot) present a completely new platform to study confinement properties predicted by topology at the nanoscale. Their work is published in the journal Physical Review B.

    For the first time, the researchers experimentally demonstrated the topological trapping of sound at the nanoscale. Acoustic phonons with frequencies around 350 GHz are trapped in semiconductor multilayer stacks of a few nanometers thickness. The structures are formed by concatenated phononic crystals with different topological phases, i.e. their acoustic bands are inverted. They show by Raman scattering experiments that acoustic phonons are topologically confined at their interface.

    The reported robust topological interface states could become a key element in engineering nanophononic resonators for sensors and phonon lasers. Other potential applications are resonators  in optomechanics, in nanoscale thermal transport and for the control of decoherence in solid state systems.

    Figure : Spatial displacement pattern |u(z)| of the topological interface phonon at 350GHz (black) together with a sketch of the semiconductor multilayer structure. The mode envelope shows a maximum at the interface between the two topologically different structures and decays evanescently into both directions away from the interface. Green and blue color schemes denote spatial regions with different topological phase. © C2N / D. Kimura
     

    Reference:
    Topological nanophononic states by band inversion,
    M. Esmann, F. R. Lamberti, P. Senellart, I. Favero, O. Krebs, L. Lanco, C. Gomez Carbonell, A. Lemaître, and N. D. Lanzillotti-Kimura, Physical Review B (2018)
    DOI: doi.org/10.1103/PhysRevB.97.155422 

    -    Centre de Nanosciences et de Nanotechnologies – C2N (CNRS/Université Paris-Sud)
    -    Matériaux et Phénomènes Quantiques – MPQ (CNRS/Université Paris Diderot)

    Contact:

    -    Martin Esmann, Post-Doctorant au C2N
    -    Daniel Lanzillotti Kimura, Chercheur CNRS au C2N

     


  • 18

    04/2018

    Intrinsic Properties of Suspended MoS2 on SiO2/Si Pillar Arrays for Nanomechanics and Optics


      Julien Chaste.

    Since a few years, it is possible to isolate sheets with thickness of an atom and width of dozens of micrometers. It is possible to proceed with metallic, insulating, or semi-conductors materials and to assemble them in various heterostructures. One of these materials is the MoS2. However, few experiences were made on suspended membranes of this material in a controlled way and where the strain can be modulated. By taking into account the 2D confinment and the high tunability of the crystalline structure, for example by means of the mechanical stress, this interseting material possesses various surprising properties for electrons, as for photons or phonons.

    Researchers of the Centre de Nanosciences et de Nanotechnologies/Centre for Nanoscience and Nanotechnology – C2N (CNRS/Université Paris-Sud), in collaboration with the University of Pennsylvania, have studied a new sample type with large monolayer MoS2 deposited on carpets of SiO2 pillars, with electrical contacts. With the control over pillars geometry, they were able to create periodic networks of high-quality mechanical resonators. Their work is published in the journal ACS Nano.

    To reach it, it was necessary, at first, to extract by microRaman, the intrinsic properties of our system: the doping, the thermal conductivity and especially the stress engendered by pillars, and this for numerous types of geometries. The researchers demonstrated for the first time that it is possible to obtain a high-quality and homogeneous system over many periods of pillars. This type of hybrid structure of  opto-electro-mechanic (NOEMS) couples at the same time the nanomechanics with interesting properties of the MoS2 as very strong photocurrent, electronical memory effects or another localized optical emission engendered by the fold of the MoS2 by pillars.

     

    Figure: On the left, some sample of monolayer MoS2 suspended on SiO2 pillars array with a schematic. On the right, a diagram of the respective peak position obtained by Raman spectroscopy, which discriminate the strain, doping or heating. It is possible to correlate a predominant MoS2 property variation with a specific pillars array design. © C2N / J. Chaste

     

    Reference:
    Intrinsic Properties of Suspended MoS2 on SiO2/Si Pillar Arrays for Nanomechanics and Optics,
    J. Chaste1, A. Missaoui1, S. Huang1, H. Henck1, Z. Ben Aziza1, L. Ferlazzo1, C. Naylor2, A. Balan2, A. T. C. Johnson2, R. Braive1,3, A. Ouerghi1, ACS Nano (2018)
    DOI: doi:10.1021/acsnano.7b07689

    1 Centre de Nanosciences et de Nanotechnologies – C2N (CNRS/Université Paris-Sud)
    2 Department of Physics and Astronomy, University of Pennsylvania, USA
    3 Université Paris Diderot, Sorbonne Paris Cité

    Contact: Julien Chaste, CNRS researcher at C2N


  • 5

    04/2018

    Silicon light-emitting diodes : spin-dependent efficient emission


      Francesca Chiodi.

    Physicists from the Centre de Nanosciences et de Nanotechnologies, the Laboratoire de Physique des Solides, and the University of Cambridge have demonstrated efficient silicon light-emitting diodes using an original manufacturing method. The device is very simple and provides a luminescence at once strong and controllable by a magnetic field at room temperature.

    Spin-dependent recombination, where only the singlet state of an electron-hole pair can recombine radiatively, can provide a precious insight on the role of spin in low spin-orbit coupling materials, such as organic semiconductors or silicon. However, in silicon, electron-hole pair recombination is highly improbable due to its indirect gap band structure. Despite the clear potential of silicon for applications, making an efficient light emitting diode (LED) with this material is a challenge, and generally requires a complex design and engineering.

    Physicists from the Centre de Nanosciences et de Nanotechnologies/Centre for Nanoscience and Nanotechnology - C2N (CNRS / Paris-Sud University) and the Laboratoire de Physique des Solides - LPS (CNRS / Paris-Sud University), in collaboration with the Optoelectronics group of University of Cambridge, have taken up this challenge. Their work, published in the journal Nature Communications, shows the possibility of producing efficient silicon LED diodes thanks to an original fabrication method based on Gas Immersion Laser Doping (GILD).

    A specificity of this technique is that the doping levels obtained are extreme, which intensifies the emission in the LEDs consisting of a junction between boron-doped silicon, intrinsic silicon and phosphorus-doped silicon (Si:B / Si / Si:P). In addition, laser doping allows to maintain a well-defined planar geometry, necessary to be able to align the magnetic and electrical fields in the LEDs and thus to overcome conventional magnetoresistance effects. By probing the spin-dependent recombination in these silicon LEDs, a spectacular increase in electroluminescence with the magnetic field has been demonstrated: 100% at room temperature and up to 300% at 150K. The proposed model describes this phenomenon by a spin-dependent radiative recombination of weakly bound electron-hole pairs. By this optoelectronic approach, it is thus possible to study the impact of the spin statistics on the luminescent emission of silicon, which appears to be a leading candidate for large-scale quantum spin electronics.

    Figure : Diagram and infrared images of Si-LEDs polarized at I = 20mA at room temperature for different levels of doping. Magneto-EL at T=150 K and I=5 mA. © C2N / F. Chiodi

     

    Reference

    Room temperature magneto-optic effect in silicon light-emitting diodes
    F. Chiodi, S.L. Bayliss, L. Barast, D. Débarre, H. Bouchiat, R.H. Friend et A.D. Chepelianskii
    Nature Communications (January 2018)
    DOI: https://www.nature.com/articles/s41467-017-02804-6

     

    Contact


    Informations complémentaires


  • 3

    04/2018

    Participation of C2N to the event "Journées de la matière condensée" 2018


      Sylvia Matzen.

    From Monday 27 to Friday 31 August 2018, on the University Campus (Saint-Martin-d'Hères) of Grenoble, will take place the 16th edition of the "Journées de la Matière Condensée" (JMC). With more than 700 participants this conference is today the biggest congress on Physics in France.

    The plenary and semi-plenary sessions will cover the full breadth of condensed matter topics including presentations of Jacqueline Bloch (Senior CNRS researcher at C2N) about « Polaritons » and of Maria Tchernycheva (Senior CNRS researcher at C2N) about « Semi-conductor nanowires ».

    32 mini-colloquia will also be held over the 5 days of the event, including the mini-colloquium co-organized by Sylvia Matzen, Associate Professor Université Paris-Sud at C2N, about « Ferroics: fundamental aspects and applications ».

            Abstract submission deadline is: 15 avril 2018

            Learn more about the JMC 2018 : https://jmc2018.sciencesconf.org/


  • 28

    03/2018

    Quandela: ultrabright single photon sources


      Pascale Senellart.

    This article was first published in the CNRS – La lettre Innovation in March 2018, under « Start-up ».

    Based on a lithography technique developed at the Centre de nanosciences et de nanotechnologies, Quandela manufactures and delivers sources of light delivering a single photon at each pulse. Its products are of interest to academia and industry in the fields of quantum computation and cryptography, and more broadly for research in quantum physics.

    For several years, researchers at the Centre de nanosciences et de nanotechnologies (Centre for Nanoscience and Nanotechnology) – C2N1 have been developing a lithography technique that makes it possible to produce a quantum dot based emitter of single photons - a single photon per pulse. These sources of light, which operate at a cryogenic temperature, have the advantage of emitting single photons with very high efficiency and with identical characteristics, making them a tool of choice for researchers of quantum photonics in academia and industry. They are of interest for both the emerging field of quantum computers and the field of perfectly secure quantum telecommunications. The start-up Quandela, issued from the Centre de nanosciences et de nanotechnologies, was founded in June 2017 to provide sources of light for these applications and more broadly to develop the building blocks for quantum technologies.

    A prematuration program, funded by the CNRS and Labex NanoSaclay, led to a robust and reproducible manufacturing process. The goal was also to work on the integration of the transmitter component on an optical fiber, which requires a precision of alignment to the tenth of a micron. These studies will create a next generation of "plug-and-play" sources: users will no longer need to mount a complex optical system to collect the emitted photons, which should help commercializing to a widespread these sources. "Thanks to this program, the founders2, researchers from the laboratory, were also able to follow HEC Challenge Plus classes to learn about entrepreneurship" says Valerian Giesz, CEO of Quandela. The start-up registered its first order at the end of 2017, from a research laboratory abroad.

    Quandela manufactures its components and continues its development by renting premises and using equipment from the Centre de nanosciences et de nanotechnologies. The company plans eventually to invest in its own equipment, in order to increase its production and development capacity. It plans to open its capital at the end of 2018.

    1 CNRS / Université Paris-Sud
    2 Valerian Giesz, CEO of Quandela; Pascale Senellart, Scientific Advisor (Senior CNRS researcher at C2N) and Niccolo Somaschi, CTO of Quandela.

    Contact : Valerian Giesz, Quandela / Pascale Senellart, CNRS

     


  • 17

    03/2018

    The first sino-french summer school « NANO3 » will take place from 2nd to 27th July 2018 at Paris-Sud University


      Eric Cassan, scientific coordinator.

    Paris-Sud University will host from 2nd to 27th July a group of chinese students at the occasion of the first sino-french NANO3 « Nanophotonics, Nanoelectronics and Nanomagnetism », organised with a strong participation of professors and researchers from C2N.

    The NANO3 school is a 4-week intensive course in nanophotonics and nanoelectronics and nano-magnetism, an outstanding field of research developed at Paris-Sud University /Paris-Saclay University. The aim of the school is to provide Chinese students with precise information on the French research system with :

    • theoretical courses,
    • lab trainings: thanks C2N micro-nano-technology facility,
    • industrial seminars with companies based on the campus : laboratoire III / V, THALES-TRT, SILTENE,
    • research projects,
    • visits of laboratories : Centre for Nanoscience and Nanotechnology (C2N), Laboratory of Solid Physics (LPS) et Institute of Molecular Sciences of Orsay (ISMO).

    The school includes elements of French culture with language courses and visits in the region of Paris. Several networking events are organized with researchers and PhD students: buffets and cocktails, meeting with members of the association « Union des chercheurs et des étudiants chinois à Paris-Sud », meeting with current PhD students financed by the CSC programme (China Scholarship Council).

    The team of professors is composed of Professors from Paris-Sud University/Paris-Saclay University and CNRS. These professors regularly teach in the Master 2 Nanosciences and other international masters.

    Professors and researchers from C2N speaking at NANO3 :
    •    Eric Cassan, Professor at Paris-Sud University/Paris-Saclay University – organizer of the summer school NANO3
    •    Béatrice Dagens, CNRS researcher – organizer of the summer school NANO3
    •    Frédéric Aniel, Professor at Paris-Sud University/Paris-Saclay University
    •    Adel Bousseksou, Associate Professor at Paris-Sud University/Paris-Saclay University
    •    Aloyse Degiron, CNRS researcher
    •    Philippe Dollfus, CNRS researcher
    •    Juan-Ariel Levenson, CNRS researcher
    •    Delphine Marris-Morini, Associate Professor at Paris-Sud University/Paris-Saclay University
    •    Damien Querlioz, CNRS researcher
    •    Nicolas Vernier, Associate Professor at Paris-Sud University/Paris-Saclay University
    •    Navy Yam, Associate Professor at Paris-Sud University/Paris-Saclay University
     
    This summer school is organized by the International Relations Office of Paris-Sud University, with a support of Campus France Chine.
     
    •    Learn more on the website www.nano3.u-psud.fr
    •    E-mail contact : nano.3@u-psud.fr

     


  • 16

    03/2018

    C2N will host the technical workshop BEAMeeting 2018 on 21-22 March


      Edmond Cambril.

    Beamer and LAB community are welcome to join the BEAMeeting 2018 on March 21 and 22 Mars at C2N in Marcoussis (near Paris).

    BEAMeetings are a technical exchange platform for BEAMER, TRACER, LAB and our new ProSEM software packages. User presentations or discussions on applications, solutions for specific issues, needs or requirements from your side are most welcome. We will summarize some presentation from the last BEAMeetings (SPIE in USA and at GenISys in Munich) and specific subjects of interest to our users in France.

    We will update on new features and enhancements and discuss wishes, needs and suggestions for future developments.

    • Date : Wednesday, March 21st 13:00 to 17:00 and Thursday, March 22nd from 9.00 till 13:00
    • Lieu : Centre de Nanosciences et de Nanotechnologies (C2N), Route de Nozay, F-91460 Marcoussis, France (near Paris)
    • Access is free of charge. For registration just send a short e-mail to Edmond Cambril / Tel. +33 (1) 6963 60 67

  • 6

    03/2018

    Recent progress in plasmon lasers


      Claire Deeb.

    Two researchers of the Centre de Nanosciences et de Nanotechnologies – C2N (CNRS/Université Paris-Sud), have recently published an article in the journal Physical Chemistry Chemical Physics (PCCP) about plasmon lasers.

    Plasmon lasers are a new class of coherent light sources that use metals for light localization and amplification. Access to this confined light that couples to the oscillating electrons of metal enables reducing the physical size and mode volume of the laser much below the diffraction limit. The race to demonstrate new plasmon nanolasers has enabled considerable progress over the last several years regarding nanocavity design, operating temperature, pumping conditions, and material efficiency of both plasmonic nanocavity and gain medium.

    This article discusses some of the latest developments of coherent nanoscopic light sources, in metallic and dielectric lasers, with a specific focus on plasmon nanolasers. The researchers highlight recent advances in plasmon lasers through plasmonic nanoparticle arrays: beam directionality, wavelength tunability, multi-modal emission, and dark and bright modes lasing. They also discuss future prospects.

    Figure : Tunable plasmon laser based on nanoparticle arrays. Scheme of the real-time tunable laser and lasing emissions shifting to longer wavelengths and then back to shorter wavelengths. © C2N / C. Deeb
     
    • Reference:

    Plasmon lasers: coherent nanoscopic light sources
    Claire Deeb and Jean-Luc Pelouard
    Phys. Chem. Chem. Phys. 2017, 19, 29731
    DOI: http://dx.doi.org/10.1039/c7cp06780a

     


  • 28

    02/2018

    A « barcode » for the fast identification of very dilute biomolecules


      Anne-Marie Haghiri-Gosnet.

    This article was first published in the CNRS – La lettre Innovation in February 2018, under « Patents and licences ».

    A team from the Centre de Nanosciences et de Nanotechnologies/Center for Nanoscience and Nanotechnology (C2N)1 has developed a microfluidic chip integrating a series of nanochannels. Under a specific electrophoretic protocol this new nanofluidic chip produces a fluorescence « barcode », which acts as a specific signature of the target biomolecule. This new technique enables the determination of molecular concentration and identification in just a few minutes, in contrast to several hours to several days with previous techniques.

    In order to concentrate and identify very dilute molecules in a solution (biological markers, pollutants, toxins...), the techniques currently available require hours, sometimes days of manipulation. The biochip invented2 at the Centre de Nanosciences et de Nanotechnologies (C2N)1 makes it possible to perform such analyses in a few minutes. Thanks to slots of different nanometric size, this biochip concentrates molecules in focal points which are located upstream or downstream relative to each nanochannel producing a « barcode », that is simply readable by optical fluorescence.

    The microfluidic chip of C2N is based on the well-known principle of electrophoresis to separate molecules: the more or less rapid migration of ions in a solution in an electric field, according to their mass and their electric charge. But the researchers have in addition used a different phenomenon, also studied for years in the laboratory, the « electropreconcentration ». Indeed, their microfluidic device – a chip on a glass – contains an element of even smaller size: a nanochannel of a few tens of nanometers in width. This nanometric channel has a high selective permeability that creates areas in the microfluidic circuit where the investigated molecules are locally concentrated. If these molecules have been marked fluorescently, they form a spot detectable by optical reading. Better: the researchers found a way to realize several nanochannels in parallel on a single chip. These channels have different widths, so that their effect can be modulated by acting on the pressure applied in the microfluidic circuit, generating a series of fluorescent spots which form a « barcode » that is specific to the molecule to be identified. A patent has been filed for the particular geometry of the chip, with several adjacent nanometric channels in the vertical direction2.

    The principle, validated with a model molecule (fluorescein), will be further tested with real biological solutions or samples containing pollutants or toxin markers. «We want to build a compact and transportable test bench, in order to work more easily with our partners», says Anne-Marie Haghiri, CNRS researcher at C2N. Presently, the fabrication of the chips is realized using electron-beam lithography. But it may be possible to use nano-printing techniques, which are less time-consuming and better suited for mass production. In the meantime, the laboratory continues to explore the fundamental phenomena that govern the efficiency of chips with nanochannels.
     
    1 CNRS / Université Paris-sud
    2 Patent FR1660855 in CNRS proprety, registered on 9/11/2016

     
    Contact: Anne-Marie Haghiri-Gosnet, CNRS researcher at Centre de nanosciences et de nanotechnologies (C2N)

     


  • 27

    02/2018

    C2N is organizing with other partners the NanoTN conference 2018 in Marrakech


      Abdelkarim Ouerghi.

    The NanoTN-2018 (Nano-Materials: Experiment and theory) conference took place in Marrakech (Morocco) on 25-28 Feb 2018. It covered all aspects of the Nanoscience and Nanotechnology of Nano- and 2D materials. The aim of the conference was also to establish networks between participants.

    NanoTN-2018 was the third edition of the NanoTN symposium, after NanoTN-2015 in Hammamet and NanoTN-2016 in Marrakech.

    Topics covered: 2D materials, Electronic properties, Functionalization, Theory, Spectroscopy/Microscopy and Devices (PV, Sensors, Electronics…), Nanocrystals , Nanochemical, Low dimentionality, Optoelectronic, Nanosciences.


  • 9

    02/2018

    Towards the optimized generation of continuous variables triple-photon states quantum entanglement


      Kamel Bencheikh.

    Physicists have discovered an unexpected theoretical track to optimize the non-linear generation of triple-photon quantum states. The conclusion: it is better to avoid a blindly taking inspiration from the analoguous and well-controlled process of double-photon quantum states generation.

    The generation of entangled triple-photons by nonlinear optical interaction would be the most direct way of producing non-Gaussian quantum statistics, which are the key to many advanced quantum protocols. What could be more natural than to draw on the knowledge acquired over the past three decades on double-photons (or twin photons), which have enabled the most astonishing demonstrations of quantum optics, to optimize the triple-photons generation? However in the best experimental conditions, less than a triple-photon every three months could theoretically be emitted from a non-linear cristal by spontaneous emission. The third order non-linear coefficient generating the triple-photons is indeed several orders of magnitude lower than that of second order, generating the twins. Physicists from the Centre of Nanoscience and Nanotechnology – C2N (CNRS/Univ. Paris-Sud) and from Neel Institute (CNRS) have theoretically demonstrated the possibility of going beyond these limits by getting out from the analogy with the twin photons generation mechanism. Their results were published in the Physical Review Letters.

    The equations controling the continuous variables triple-photon states quantum entanglement generation process do not have known analytical solution. Physicists have proceeded by a so-called perturbative method by considering up to the fifth order terms. They solved the resulting equations by numerical methods. They demonstrated that simultaneously with pumping, triggering the non-linear effect with seed photons at the same frequency as the emitted triple-photons is necessary to reach the triple-photons continuous variable entanglement. Researchers have also shown that entanglement increases when the seeding rate increases. A singular mechanism since in the case of twin photons generation, the quantum entanglement is destroyed by the injection. The injection mechanism also makes it possible to increase by several orders of magnitude the efficiency of the third-order non-linear interaction. These theoretical results break down the barriers to an experimental realization on which the teams from C2N and Neel Institute began to work as part of a joint research project.

    This work opens the way for a deep investigation of triple-photons quantum properties, as well as the development of advanced quantum protocols for cryptography.

     

    Figure: Gain (left) and variances (right) distribution of triple-photons quautum states showing the three lobes as a function of the phase. © C2N / K. Bencheikh

     

    More about the publication

    Continuous variables triple-photon states quantum entanglement
    E. A. Rojas Gonzalez, A. Borne, B. Boulanger, J. A. Levenson, and K. Bencheikh
    Physical Review Letters (January 2018)
    DOI: https://doi.org/10.1103/PhysRevLett.120.043601

    Contact

    Kamel Bencheikh, CNRS Researcher (kamel.bencheikh@c2n.upsaclay.fr)  

    Additional informations

    - Centre for Nanoscience and Nanotechnology – C2N (CNRS/Université Paris-Sud)

    - Department of Engineering Sciences, Uppsala University, Sweden

    - Weizmann Institutes of Science, Israel

    - Neel Institute, CNRS laboratory associated to Université Grenoble Alpes and Grenoble INP


  • 22

    01/2018

    Zubair Iftikhar, PhD Student at C2N, rewarded with a C’Nano 2017 thesis prize


      Zubair Iftikhar.

    Six PhDs were awarded for the excellence of their theses during the "C’Nano, the Nanoscience Meeting", interdisciplinary congress that gathered more than 200 researchers and engineers from nanoscience and nanotechnology fieldsthat took place on 5-7 December 2017 at INSA Lyon.

    Zubair Iftikhar, PhD student from Université Paris Saclay at C2N from 2013 to 2016, was awarded the thesis prize from C'Nano - Club nanoMétrologie, for his thesis entitled "Charge quantization and Kondo quantum criticality in few-channel mesoscopic circuits", under the direction of Frédéric Pierre.


  • 15

    01/2018

    Applications open for the thematic school on Physics of Solar cells


      Stéphane Collin.

    A thematic school on Physics of Solar cells: from basics to nanoscience supported by C2N will be held from 25-30 March 2018, at "Les Houches School of Physics" in French Alps. Apply before 31 January to participate!

    This school is focused on the physics of solar cells. The goal is to cover the fundamental and basic aspects of photovoltaic devices, and the most advanced concepts that enable the highest efficiencies. It will be shown that the recent progress of the different technologies (silicon, thin-films,…) are based on similar concepts and should mutually inspire each other. A special emphasis will be given to nanoscience and nanotechnologies, which bring new tools and concepts to break the limits of conventional solar cells.

    The targeted audience is focused on young scientists (phD or post-docs), but senior scientists new to the field of PV, or wishing to enlarge their knowledge in nanoscience and nanotechnologies are also very welcome.


  • 15

    01/2018

    (in french) Des composants bio-inspirés


      Damien Querlioz.

    (in french)

    « Nous aussi, on a galéré », se souvient Damien Querlioz, chercheur CNRS au Centre de nanosciences et de ­nanotechnologies de Paris-Saclay. Il évoque les temps où ses recherches sur des composants neuromorphiques n’étaient guère à la mode, comme l’étaient celles sur le deep learning neuro-inspiré. « Dans mes projets de financement, j’évitais même le mot neurone ! Maintenant, tout le monde le fait. » C’est qu’une prise de conscience a eu lieu. « Le programme AlphaGo consomme dix fois plus d’énergie qu’un joueur de go ­humain », rappelle Julie Grollier, chercheuse CNRS dans le laboratoire commun entre l’organisme et Thales, sur le plateau de Saclay. Augmenter la taille des réseaux de neurones artificiels risque d’atteindre des limites dont les ­industriels sont conscients. En outre, il est impossible de disposer des bienfaits de cette intelligence artificielle dans les mobiles, trop peu puissants ; il faut ­recourir aux réseaux de communication et à des connexions à de grandes fermes de serveurs. D’où ce nouveau retour vers le ­vivant et la formidable efficacité du cerveau, qui consomme très peu d’énergie, même pour des ­tâches complexes. L’un de ses ­secrets, encore inimité, est de ne pas séparer la mémoire et le calcul, évitant ainsi des échanges d’informations incessants et consommateurs en énergie. Tout est codé dans les neurones et les synapses, sans pouvoir identifier des zones de mémoire ou de calcul. « Il faut tout repenser ! », constate Julie Grollier. Et le mouvement a commencé. IBM produit une puce, TrueNorth, un réseau de neurones composé de transistors classiques mais agencés de façon à consommer beaucoup moins que des équivalents sur cartes graphiques. Mais cette puce n’apprend pas : on programme le câblage de ses neurones (synapses) en fonction de calculs préliminaires effectués sur de gros serveurs. NEUROMORPHISME D’autres fabricants utilisent des composants « programmables », dits FPGA, pour essayer de faire un peu mieux qu’avec les cartes graphiques. Mais ce n’est pas encore du « vrai » neuromorphisme. Pour cela, il faut des composants dont les propriétés physiques peuvent varier, à la manière dont le poids d’une synapse change. C’est la grande famille des memristors, dont la résistance se modifie en fonction des courants électriques qui les ont parcourus dans le passé. Ainsi, on renforce ou affaiblit une ­synapse artificielle en faisant circuler plus ou moins d’électrons. Des matériaux disposant de plus de deux états magnétiques sont aussi de bons candidats. Pour l’instant, seuls des composants de laboratoires de quelques neurones et synapses ont pu être obtenus. Damien Querlioz et Julie Grollier, tous deux financés par le conseil européen de la recherche, estiment que, dans cinq ans, un composant bio-inspiré sera possible, consommant mille fois moins d’énergie et tenant sur un centimètre carré. Voir l'article du monde
    LE MONDE SCIENCE ET TECHNO | 09.01.2017 à 17h52
    Par David Larousserie

    Article dans " Le journal du CNRS"


  • 13

    12/2017

    Damien Querlioz invited to talk with science journalists about brain-inspired computation


      Simon Jumel.

    CNRS and AJSPI (the French Association of Science Journalists) organized on Tuesday, December 12 a breakfast in order to discuss "Brain-inspired computing for the development of the next generation computers". This informal meeting brought together scientists and journalists, the former sharing their research and the latter able to ask questions and enlarge their knowledge about the topic and to prepare future articles.

    It was attended by 12 journalists, who listened to Damien Querlioz from C2N and Julie Grollier from Unité Mixte de Physique CNRS/Thalès.


  • 4

    12/2017

    FORWARD project: Aloyse Degiron awarded ERC CONSOLIDATOR 2017


      Aloyse Degiron.

    To detect or generate complex light beams that are increasingly needed in biology and photonics (light with non-zero angular momentum and non-classical light), it is necessary to rely on bulky and sophisticated setups, considerably limiting their potential. The FORWARD project aims at obtaining the same functionalities with a new generation of optoelectronic components of submicron thickness in the near infrared range. This ambitious objective implies to devise radically new ways of creating and manipulating complex light at the nanoscale. In FORWARD, this challenge will be addressed by hybridizing two classes of artificial media—colloidal quantum dots (CQDs) and metamaterials—and leveraging advanced cooperative behaviours within the hybrids, which will be pumped electrically. This initiative can be seen as the first of its kind that takes a unified and multidisciplinary view at artificial media, opening new horizons for synthetic composite materials in optics, electronics and optoelectronics.

    Bio: A. Degiron received the PhD in physics from the University of Strasbourg. In 2005 he became a postdoc at Duke University (USA) and in 2008 he was appointed assistant research professor. In 2009 he returned to France and works at Centre de Nanosciences et de Nanotechnologies in Orsay as a tenured CNRS scientist ever since. His current research interests focus on metamaterials, self-assembled nanocrystals and optoelectronics at the nanoscale.


  • 27

    11/2017

    Phase Stochastic Resonance in a Forced Nanoelectromechanical Membrane


      Rémy Braive.

     

    Authors and Affiliation

    Avishek CHOWDHURY (C2N – Marcoussis)

    Sylvain BARBAY (C2N – Marcoussis)

    Marcel CLERC (Universidad de Chile - Santiago)

    Isabelle ROBERT-PHILIP (C2N – Marcoussis)

    Rémy BRAIVE (C2N – Marcoussis, Université Paris-Diderot)

     

    Abstract

    Stochastic resonance is a general phenomenon that can seem paradoxical at first, whereby noise present or injected in a system can enhance the detection of a small signal. It is usually observed in one-dimensional bistable systems subjected to a small amplitude modulated signal. In our work recently published in Phy. Rev. Lett., we show experimentally the emergence of phase stochastic resonance in the bidimensional response of a forced nano-electromechanical membrane. It results in the enhancement of a weak phase modulated signal thanks to the addition of phase noise. A theoretical model, confirmed by the experimental measurements, reveals the unusual role of phase noise that acts multiplicatively. These results may open interesting prospects for phase noise metrology or coherent signal transmission applications in nanomechanical oscillators. Moreover, our approach, due to its general character, may apply to various systems and open novel opportunities for stochastic resonance applications.

    "accepted for publication at Physical Review Letters journal, on-line available soon "

    Link to the article

     


  • 8

    11/2017

    Plasmon fingerprint in Au Nanocrystal assemblies


      Claire Deeb.

    Hydrophobic Au nanocrystal assemblies (both ordered and amorphous) were dispersed in aqueous solution via the assistance of lipid vesicles. The intertwine between vesicles and Au assemblies was made possible through a careful selection of the length of alkyl chains on Au nanocrystals. Extinction spectra of Au assemblies showed two peaks that were assigned to a scattering mode that red-shifted with increasing the assembly size and an absorption mode associated with localized surface plasmon that was independent of their size. This plasmon fingerprint could be used as a probe for investigating the optical properties of such assemblies. Our water-soluble assemblies enable exploring a variety of potential applications including solar energy and biomedicine.

     

    Published in:

    Water-Dispersed Hydrophobic Au Nanocrystal Assemblies with a Plasmon Fingerprint

    Nailiang Yang, Claire Deeb, Jean-Luc Pelouard, Nordin Felidj, and Marie-Paule Pileni

    ACS Nano, 2017, 11 (8), pp 7797–7806

     

     

     

     


  • 27

    10/2017

    Jacqueline Bloch laureate of the CNRS Silver Medal


      Jacqueline Bloch.

    Internationally recognized as an expert in quantum and non-linear optics, Jacqueline Bloch is exploring the ultimate light matter coupling in semiconductor nanostructures. Hired in 1994 as a permanent CNRS researcher (CR) at the Microstructure and Microelectronic Laboratory (L2M), she initiated experimental research on semiconductor microcavities. She is particularly interested in the strong coupling regime between light and matter, a regime which gives rise to the formation of hybrid quasi-particles named cavity polaritons. In 2008, her pioneering results on polariton condensation in microstructures, opened the way to the investigation of these quantum fluids of light in microstructures sculpted at the micron scale thanks to the technological facilities available in the clean room of her laboratory. Since then, her career has been laden with a series of original and spectacular achievements: with her research group she has studied various non-linear physical phenomena, such as superfluidity, frustrated systems, topology or quantum phase transition in open systems. Promoted as Research Director in 2011, she is now contributing to the organization of the new Center for Nanoscience and Nanotechnologies (C2N) where she is the co-director of the Photonics Department. Hired in 2015 as Professor “Chargée de cours” at Ecole Polytechnique Physics Department, she is awarded the same year the prestigious Jean Ricard Prize of the French Physical Society.

    La Médaille d'argent du CNRS distingue un chercheur pour l'originalité, la qualité et l'importance de ses travaux, reconnus sur le plan national et international. Lien vers le site du CNRS


  • 27

    10/2017

    Light on graphene: Marijana Milicevic, doctoral student of C2N laureate of a L'Oréal grant


      Marijana Milicevic.

    Graphene (2004 discovery awarded with the Nobel Prize for Physics in 2009) is the best conductor of electricity known to date. This new class of extremely thin materials consisting of a single layer of carbon atoms, has outstanding electronic, optical and mechanical properties that will potentially revolutionize the world of microelectronics. However, these innovative materials that captivate physicists remain difficult to manipulate in the laboratory because their study requires an experimental resolution on the scale of the infinitely small, the atom. Originally from Belgrade, Serbia, and currently PhD student at the Center for Nanosciences and Nanotechnology at the Marcoussis site, Marijana Milicevic has chosen to recreate this material in a new way, using light, in a photonic simulator. The objective of this tool is to use photons, constitutive particles of light, to recreate graphene in the laboratory in order to study it with better control. "The photons of the simulator are confined to micrometrically sized structures to equal or surpass the particular electronic properties of the material. Remarkably, Marijana studies particular structures of graphene, called "edge states", intrinsically very stable, to ensure transport without energy dissipation.

     


  • 25

    10/2017

    (in french) Damien Querlioz, lauréat de la médaille de bronze du CNRS


      Damien Querlioz.

    The CNRS Bronze Medal 2017 was awarded to 40 researchers, 26 women and 14 men. It rewards the first work of a researcher, who makes him a talented specialist in his field. Damien Querlioz, CNRS Research Scientist at C2N, is one of the lucky winners for his work on memories and bioinspired systems. Damien Querlioz is in charge of the C2N INTEGNANO group and is also an expert at the Observatory of Micro and Nanotechnologies, a member of the interdisciplinary GDR BIOCOMP board and a member of the management committee of the European COST MEMOCIS program. In 2016, Damien Querlioz won a European Research Council Grant (ERC) on smart memories capable of inference using the physics of nanodevices (project ERC NANOINFER).

    CNRS website

    INSIS laureate Starting Grants

    Description of the European project


  • 24

    10/2017

    Mapping in real space antiferromagnetic order at nanoscale


      Jon-von Kim.

    Using an artificial atom in diamond as an ultrasensitive magnetic field detector, physicists have for the first time imaged the leakage field radiated by a compound of the vast family of antiferromagnets. This observation allowed them to study the effect of an electric field on the sinusoidal modulation of the antiferromagnetic order in a multiferroic material.

    INP website

    NSIS website

    Image caption: (left) An artificial atom (center NV represented by the green arrow) inserted into a diamond tip is used to map the magnetic field radiated by an antiferromagnetic material. Under radiofrequency excitation, the amplitude of the magnetic field is coded on the fluorescence intensity of the NV center illuminated by a green laser. (right) Quantitative mapping of the magnetic field produced by the sinusoidal modulation of the antiferromagnetic order in a 30 nm thick BiFeO3 film.


  • 23

    10/2017

    A topological laser realized at the C2N


      Jacqueline Bloch et Philippe Saint-Jean.

    The work of researchers from the Center for Nanosciences and Nanotechnologies (CNRS - Université Paris-Sud) in Marcoussis, France, in collaboration with a researcher from the Università di Trento in Italy, has led to a major breakthrough in topological physics: the realization of the first topological laser. Such a laser implements a resonating mode that is intrinsically protected, thanks to the topological properties of its architecture, against external perturbations and fabrication defects.

     The discovery of topological phase transitions in condensed matter, which was awarded the 2016 Noble prize in physics, has profoundly influenced the field of solid-state physics. The hallmark of these phase transitions is the emergence of localized states whose properties are unaffected by the presence of defects, dislocations and other kinds of disorder. For example, topological insulators, which are one of the most notable manifestations of these exotic phases, present an electrical conductivity along their edge that is perfectly insensible to the presence of irregularities. Recently the extension of this topological physics to the realm of photonics has triggered considerable efforts to engineer novel generations of optical devices (e.g. waveguides, optical isolators, diodes, and, of course, lasers) whose performances are unaffected by perturbations of their environment.

    In the case at hand, the researchers of the C2N have built a topologically robust laser by taking profit of the physics of cavity polaritons, a half-light /half-matter quasi-particle confined in cylindrically-shaped optical cavities (see the figure on the right). By coupling these micro-cylinders together, they formed a uni-dimensional lattice that presents well-defined topological properties leading to the emergence of localized photonic modes at the edges of this lattice. Then, by using the gain associated to the matter part of polaritons, they triggered a laser emission from one of these modes, thus realizing the first topological laser.

    Legend image: Electron microscopy image of a lattice of micro-cylinders including an artificial representation of the lasing emission. A schematic image of one of these cylinders is shown on the right where a quantum well (QW) is inserted between two distributed Bragg mirrors (DBR).

    Article link


  • 23

    10/2017

    (in french) Filtrer la lumière photon par photon


      Pascale Senellart.

    Using an artificial atom capable of blocking or letting the photons of a laser pass by, CNRS researchers, in collaboration with the University of Queensland, have taken an important step towards the development of deterministic quantum optical logic gates ....

    INP website

    INSIS website


  • 23

    10/2017

    Will the computer of tomorrow be bio-inspired? Damien Querlioz enriches the debate!


      Damien Querlioz.

    As part of the cycle of conferences and debates "Dialogues - Keys to understand", taking place every 4th Thursday of the month, CNRS, CNAM and RFI propose a new conference on the computers of tomorrow, at the Museum of Arts and Crafts in Paris, on October 26, 2017 at 18:30. Damien Querlioz, C2N researcher and CNRS 2017 bronze medalist, took part in this fascinating debate with Laurent Largent, Director of the Femto-ST Institute (CNRS / University of Franche-Comté). The former, whose main research work is aimed at developing neuromorphic-type computing machines that completely question our conception of the computer as we currently perceive it, presented, during this debate, the evolutions and current and future scientific advances in this area.

    INSIS website

    CNAM website


  • 23

    10/2017

    Heat Coulomb Blockade of one Ballistic Channel


      Anne Anthore et Frédéric Pierre.

    Quantum physics rules charge and heat transport in low dimensional conductors. Exploring the new quantum laws of heat transport is a particularly challenging field of research. Indeed, there is no thermal equivalent of the ammeter and applying small but well-known temperature differences within nanoscale circuits is technically difficult.

    Physicists from C2N (CNRS-Paris Diderot University-Paris Sud University) overcomes this challenge by probing locally the temperature with ultra-sensitive noise measurements within a highly tunable hybrid metal-semiconductor nanocircuit. They have demonstrated that the classical law of heat resistance composition does not hold anymore. In particular, the heat evacuation from a small circuit node connected by perfect (ballistic) elementary quantum conductors is found systematically reduced by one thermal conductance quantum. This phenomenon results from electronic interactions. This work is published online in Nat. Phys. (https://www.nature.com/nphys/research/).


  • 25

    09/2017

    Yellow nano-bricks road for the light


      Anatole LUPU.

    For a long time optics evolution was based on the exploitation of the properties of so-called "natural" optical media, which are homogeneous and continuous on the wavelength scale. The advent of metamaterials dawned the era of new artificial media with exotic properties not encountered in the nature, leading to the demonstration of the invisibility cloak or the perfect lens based metamaterials with a negative index. However most of these demonstrations are confined to the field of microwaves.

    The two main obstacles preventing the use of metal metamaterials in the field of optics are: i) the technological difficulty of manufacturing multilayer structures; ii) the optical losses due to absorption of the metal. To circumvent these issues we consider a composite guiding structure made of a 2D plasmonic metasurface located on the top of high index silicon on insulator waveguide. The objective is to achieve an efficient control over the flow of the light in the waveguide using effective index variation induced by the metasurface resonance.

    By following this approach our team performed the demonstration of the first plasmonic metasurface based graded index lens integrated on a Silicon waveguide for operation in the near infrared domain. This enabling technology is quite generic and can be adapted to different type of planar lightwave circuits platforms: Silicon, GaN/AlN, InGaAsP/InP, doped silica glass etc.

    Figure 1 : Photography of the metasurface made of gold nanowires on silicon.

    Figure 2: Full 3D simulation of the light intensity inside the silicon at 190THz.Y. Fan, X. Le Roux, A. Korovin, A. Lupu, A. de Lustrac, “Integrated 2D graded index plasmonic lens on a Silicon waveguide for operation in the near infrared domain,” ACS Nano 11, 4599–4605 (2017).Lien vers l'article


  • 21

    09/2017

    C2N co-organizes the 9th Russian-French Workshop on Nanosciences and Nanotechnologies (RFWNN 2017), Suzdal (Russian Federation), 3-7 October 2017


      C2N.

    Since 2004, CNRS organizes, together with Russian research organizations and world-famous physics and chemistry institutes, scientific workshops covering the fields of nanosciences and nanotechnologies. The aim is to strengthen existing French-Russian collaborations, to foster new collaborations and, more generally, to propose a sample of the recent progress in France in these domains. These workshops, which take place alternatively in France and in Russia, have allowed the two partner countries to develop solid and long-lasting bilateral collaborations, a good example being the International Associated Laboratory ILNACS devoted to nanostructures of compound semiconductors, the scientific coordination of which is the task of C2N (see http://www.lpn.cnrs.fr/fr/ELPHYSE/ILNACS/).

    After the Novosibirsk (2013) and Montpellier (2015) workshops, the 9th event in this series will take place in Suzdal, near Moscow. C2N is strongly involved in this event, through the coordination of the French participation, the co-chairing of the meeting and three invited talks.

    Site de la conférence


  • 21

    09/2017

    Press release: The first artificial nano-neuron capable of voice recognition is born


      Damien Querlioz.

    Researchers from the CNRS / Thales Joint Physics Unit, the Center for Nanosciences and Nanotechnologies (CNRS / Université Paris Sud), in collaboration with American and Japanese researchers, have just developed the first artificial nano-neuron capable of recognizing figures pronounced by different speakers. Like the recent development of electronic synapses, this electronic nano-neuron, described in a Nature article, is a key breakthrough for artificial intelligence and its applications.

    CNRS press release


  • 15

    09/2017

    C2N participates in the 2017 edition of the Fête de la Science


      Communication.

    Again this year, the C2N opened its doors to schools and the public on the occasion of the Science Festival. On Sundays various workshops were offered that were supervised by scientists:

    "The nano insect": Observation of insects at the nanoscale by electron microscopy. (workshops every 45 minutes)

    "Initiation to the Nano-world": A first step towards the amazing properties of the infinitely small. Workshops and demonstrations were held about the colors of the nano-world, microscopy and the magic of nanoparticles. These open access workshops for young and old introduced the little-known world of nanoscience and nanotechnology and how it can be exploited on a daily basis.

    Nanotechnology tools Nanotechnologies? What do these terms mean to you? : This animation aimed at demystifing these concepts and demonstrating their usefulness by a guided tour of the Micro-Nano Technologies Platform.

    "Fun Physics" Experiments for young and old about magnetism, electricity, vacuum, nanoscience and many more, led by scientists. The workshops offered free access all day long.


  • 27

    07/2017

    Neuromorphic computing with nanoscale spintronic oscillators


      Damien Querlioz.

    Jacob Torrejon, Mathieu Riou, Flavio Abreu Araujo, Sumito Tsunegi, Guru Khalsa, Damien Querlioz, Paolo Bortolotti, Vincent Cros, Kay Yakushiji, Akio Fukushima,Hitoshi Kubota, Shinji Yuasa, Mark D. Stiles ,Julie Grollier

    Neurons in the brain behave as nonlinear oscillators, which develop rhythmic activity and interact to process information1. Taking inspiration from this behaviour to realize high-density, low-power neuromorphic computing will require very large numbers of nanoscale nonlinear oscillators. A simple estimation indicates that to fit 108 oscillators organized in a two-dimensional array inside a chip the size of a thumb, the lateral dimension of each oscillator must be smaller than one micrometre. However, nanoscale devices tend to be noisy and to lack the stability that is required to process data in a reliable way. For this reason, despite multiple theoretical proposals2, 3, 4, 5 and several candidates, including memristive6 and superconducting7 oscillators, a proof of concept of neuromorphic computing using nanoscale oscillators has yet to be demonstrated. Here we show experimentally that a nanoscale spintronic oscillator (a magnetic tunnel junction)8, 9 can be used to achieve spoken-digit recognition with an accuracy similar to that of state-of-the-art neural networks. We also determine the regime of magnetization dynamics that leads to the greatest performance. These results, combined with the ability of the spintronic oscillators to interact with each other, and their long lifetime and low energy consumption, open up a path to fast, parallel, on-chip computation based on networks of oscillators.

    article link


  • 24

    07/2017

    (in french) Proposition de thèse: Mise au point de procédés de structuration de l’acier par gravure sèche associée à des traitements thermochimiques


      Stephane GUILET.

    (in french)

    Cette annonce de proposition de thèse a expiré.

     

    Sujet de thèse

    Cette thèse est une co-tutelle IJL/C2N. Nous proposons au candidat de développer des procédés de gravure réactive par plasma halogéné de la surface d’aciers inoxydables austénitiques et martensitiques à l’échelle micrométrique et/ou nanométrique. Il réalisera ce travail au C2N (Centre de Nanosciences et de Nanotechnologies ; Université Paris-Saclay) où il disposera d’un équipement de gravure ICP/RIE et de moyens de caractérisation de la phase plasma et des motifs réalisés (sondes ioniques, spectroscopie optique d’émission, spectrométrie de masse, MEB, AFM, profilométrie…). Il travaillera en étroite collaboration avec un post-doctorant, recruté à l’IMN (Institut des Matériaux Jean Rouxel ; Université de Nantes), dont les activités porteront principalement sur le développement d’un modèle de gravure permettant d’appréhender de façon exhaustive les mécanismes d’interaction plasma-surface qui se produisent au cours du procédé. Les verrous technologiques et scientifiques résident dans la complexité du matériau à graver (poly-atomique, poly-cristallin, joints de grain, effets magnétiques), et l’obtention d’un masquage très sélectif adapté à la géométrie des pièces.

    A l’IJL (Institut Jean Lamour ; Université de Lorraine), le doctorant appliquera des traitements thermochimiques (nitruration, carburation) par plasma et à basse température sur les substrats d’acier structurés. La problématique est de permettre, à minima, de conserver les propriétés des motifs créés par gravure et donc les fonctionnalités visées, tout en renforçant globalement la structure afin d’améliorer la durée de vie des pièces. La résistance à la corrosion des matériaux traités est également un enjeu important. Après traitement, le doctorant devra donc s’impliquer dans la caractérisation des échantillons :

    • Topographie de surface et dimensions des motifs renforcés: profilométrie tactile, microscopie confocale, microscopie interférométrique en lumière blanche, AFM, MEB, MET
    • Aspect chimique et structural : métallographie, micro et nano-dureté, DRX, microsonde de Castaing, SIMS, SDL
    • Résistance à la corrosion : mesures électrochimiques stationnaires, spectroscopie d’impédance électrochimique
    • Mouillabilité : mesure d’angle de contact sur banc Digidrop
    • Etudes tribologiques : frottement de type pin-on-disc

  • 24

    07/2017

    H2020 Marie Curie Actions- Innovative Training Network INDEED Innovative Nanowire DEvicE Design- Doctoral Research Fellowship (PhD) Flexible nanowire light emitting diodes


      Maria Tchernycheva.

    PhD Research project

    Flexible optoelectronic devices provide an amount of new functionalities and have the potential to open up a new branch of industry. In particular, flexible light emitting diodes (LEDs), are today a topic of intense research driven by applications such as bendable displays, conformable light sources, bio-medical devices, etc. Today the flexible technology is dominated by organic semiconductors, which however exhibit low efficiency and a limited lifetime especially for the blue spectral range. For example, organic LEDs have a much lower luminance and a shorter lifetime in comparison to the LEDs based on inorganic nitride semiconductors. However, the inorganic semiconductor devices are mechanically rigid; the fabrication of flexible devices from conventional thin film structures is quite challenging and requires micro- structuring of the active layer. To avoid the micro-structuring step, it is advantageous to shrink the active element dimensions and to use bottom-up nanostructures, such as nanowires, instead of two-dimensional films. Nanowires show remarkable mechanical and optoelectronic properties stemming from their anisotropic geometry, high surface-to-volume ratio, and crystalline perfection. They are mechanically flexible and can stand high deformations without plastic relaxation. Polymer-embedded nanowires offer an elegant solution to create flexible optoelectronic devices, which combine the high efficiency and the long lifetime of

    norganic semiconductor materials with the high flexibility of polymers. The objective of this PhD project is to develop a reliable technology for red, green and bleu nanowire flexible micro-LEDs and to demonstrate a prototype of a display. Nanowire arrays embedded in a flexible film and lifted-off from their native substrate will be used as the active material. The lift-off and transfer procedure enables the assembly of free-standing layers of nanowire materials with different bandgaps without any constraint related to lattice- matching or growth conditions compatibility [1]. This concept therefore allows for a large design freedom and modularity since it enables combination of materials with very different physical and chemical properties, which cannot be achieved by monolithic growth. For RGB LEDs nanowires of different semiconductor materials (GaAsP and InGaN) will be employed.

    The PhD candidate will focus on the technological development of the displays using clean-room facilities of the C2N and on the device testing using optical spectroscopy and microscopy set-ups (photoluminescence, electroluminescence, EQE, electron beam induced current microscopy, etc).


  • 24

    07/2017

    C2N microrobot: double world champion in microrobotics competition


      Gilgueng HWANG - Laurent COURAUD.

    French team showed the strength by winning two champion titles in international mobile microrobotics challenge held at Singapore in 2017. It was held during the international conference on robotics and automation having more than 3200 participants.

    The C2N team named NOMAD participated in this year edition from 27 May to 2 June 2017. They participated in two competitions (« mobility/precision « and « best-in-show «) and the champion titles of both events went all to the C2N team. Although the team had already won in the previous editions of 2011, 2012, 2013 and 2014, it is the first time for the team won the double champions. Not participating in the edition of 2016, the team prepared and brought their new mobile microrobots having much smaller, more precise and more functional features to Singapore to compete with the other three teams came up to the final round. The team was led by Gilgueng Hwang (CNRS researcher) who has been working on the research activities of mobile microrobots in microfluidics at C2N, Marcoussis. Laurent Couraud (CNRS engineer) has been working on the development of virtual reality microrobotic simulator with force feedback joystick device which was presented in the « best-in-show » competition. This system could potentially help users the operation of microrobots. Alisier Paris (1st year PhD student) has been working on the modeling/design and control of the developed microrobots which was essential to win the « mobility/precision « competition by factor 4 higher scores than the second team. The smaller and more precise microrobots of the C2N team showed their excellent performances and advanced micro/nanotechnologies through this event. Particular thanks should be given to Dominique Decanini (CNRS research engineer) for two-photon 3D nanolithography which is essential to fabricate microrobots in the cleanroom of C2N, Marcoussis.

    Recent rapid writing module upgrade helped to accelerate the process. The team will go forward the new technical and scientific challenges. The next year edition will held in Brisbane, Austrailia.

    For more information, contact to gilgueng.hwang@c2n.upsaclay.fr

    http://www.lpn.cnrs.fr/fr/NANOFLU/Nomad.php

     


  • 26

    06/2017

    15th Nano and Micro Systems workshop Nano/Micro systems for health and safety


      GDRI NAMIS.

    NAMIS is an international research network on Nano and Micro Systems initiated by the french National Center of Scientific Research (CNRS) and the Institute of Industrial Sciences (IIS) of the University of Tokyo. NAMIS was officially founded November the 2th, 2005 by 6 European and Asian organizations: CNRS (France), IIS/University of Tokyo (Japan), EPFL (Switzerland), IMTEK (Germany), SNU (Korea) and VTT (Finland). In the 2006-2010 period, new organizations from Canada (Polytechnique Montréal), South Korea (KIMM), France (ESIEE/université Paris- Est), Japan (Tohoku University), Taiwan (NTHU) and USA (University of Washington) successively joined NAMIS. In 2016 Tohoku university left NAMIS network while MESA+ Institute of Technology (The Netherlands) was welcome as a new partner. The network now gathers 12 organizations from 10 countries representing more than 90 high rank laboratories or Institutes.

    15th Nano and Micro Systems workshop

    Nano/Micro systems for health and safety

    June 26th-28th, 2017 Interciti Hotel,Daejeon, South Korea


  • 16

    06/2017

    The C2N, 1 year already !!!


      C2N.

    Come celebrate the 1 year of C2N, Friday, June 16, Marcoussis site

  • 14

    06/2017

    (in french) IONS Paris 2017 International OSA Network of Students


      C2N.

    The Student Chapter of Optics – Paris (SCOP) will host the International OSA Network of Students (IONS) conference in its 2017 version (http://ionsparis.osahost.org/). The main goal of this event is to strengthen a worldwide network of young researchers working in optics and nanosciences. A hundred participants are expected in Paris-Saclay University (École Polytechnique and Paris-Sud-C2N) between the 14th and the 17th of June.The conference technical program contains keynote speakers as well as oral and poster presentations. The exhibition, beverage breaks, the event reception, the outreach activities and the social day will encourage and support meeting with peers and colleagues from more than 15 different countries.

    Conference web site: http://ionsparis.osahost.org/


  • 24

    04/2017

    Birth of electro-optical nanodiodes- Fabrice Raineri


      Fabrice Raineri.

    Researchers from C2N, in collaboration with STMicroelectronics and Paris-Diderot University, have designed and manufactured silicon-based integrated laser nanodiodes that are able to transfer optical electrical information very efficiently within a chip. These resultsd have been published in Nature Photonics.

    INSIS website

    Université Paris Diderot website


  • 24

    04/2017

    HYPNOTIC project carried by F. Raineri awarded with a 2016 ERC CONSOLIDATOR grant


      Fabrice Raineri.

    Fabrice Raineri is a researcher in the NanoPhotonIQ team of the Center for Nanosciences and Nanotechnologies, specialising in Nano-lasers for the optimization of telecommunications, nonlinear optics and nanotechnologies.  He is one of the 2016 ERC Consolidator award winners for the HYPNOTIC project, which focuses on the development of nano-lasers, extremely compact and efficient light sources needed for the future of information and communication technologies.

    INSIS website

    Université Paris Diderot website

    Légende photo : Photographie en microscopie électronique à balayage d’un nanolaser hybride en semiconducteur III-V sur Silicium


  • 10

    03/2017

    ERC : Damien Querlioz and Daniel Lanzillotti Kimura - INSIS laureate 2016 - Starting Grants


      Damien Querlioz.

    ERC Starting Grants from the European Research Council (ERC) support young researchers who obtained their PhDs two to seven years ago. 325 projects were selected in 2016 from all disciplines and include 46 French laureates, six of whom are researchers in INSIS laboratories.

    INSIS laureate  ERC Starting Grant

    Damien Querlioz laureate ERC Starting Grant bourse


  • 9

    03/2017

    Record de froid pour les électrons d’un circuit électrique de taille micrométrique


      Frédérique Pierre.

    Des physiciens ont refroidi des électrons au sein de circuits électriques micrométriques à une température de 6 millikelvins. Cette performance a été rendue possible par l’utilisation d’un dispositif de mesure de température in situ combinant trois techniques différentes. Lien vers l'article du CNRS

    Par où passe la chaleur dans les circuits quantiques ?

    La physique quantique régit le transport d’électricité et de chaleur à travers les conducteurs de très petites dimensions. L’étude de tels conducteurs permet d’établir la mécanique quantique à l’échelle mésoscopique, intermédiaire entre l’atome et le monde macroscopique, et également d’élucider les nouvelles lois du transport qui émergent dans les nanocircuits.

    En conséquence du double caractère à la fois ondulatoire et corpusculaire des particules, un conducteur quantique s’apparente à un guide d’onde électronique constitué de plusieurs modes élémentaires appelés canaux de conduction. Comme en transport classique, chaque canal est caractérisé par ses conductances électrique Ge et thermique Gth. La mécanique quantique se manifeste tout d’abord par les valeurs de Ge et Gth qui s’expriment simplement en fonction de la charge de l’électron et des constantes de Boltzmann et de Planck. Alors que la loi classique de composition des conductances électriques est vérifiée pour N canaux parfaitement transmis en parallèle, il est prédit qu’elle est violée pour les conductances thermiques. En effet, un unique canal parmi N est bloqué spécifiquement pour le transport de chaleur. C’est le résultat des corrélations quantiques entre canaux de conduction, induites par l’interaction coulombienne.

    La démonstration expérimentale de cette prédiction, appelée blocage de Coulomb de la chaleur, fait l’objet d’un article publié à Nature Physics par des chercheurs du CNRS et de l’université Paris-Diderot, travaillant au Centre de Nanosciences et de Nanotechnologies (CNRS-UPsud).

    Pour parvenir à ce résultat les chercheurs de l’équipe Transport Quantique ont injecté quelques femto Watts (10-15 W) de puissance dans une électrode métallique micrométrique. A des températures de quelques centièmes de degrés au-dessus du zéro absolu (-273.14°C), la puissance injectée chauffe légèrement l’électrode et est principalement évacuée par deux très petits conducteurs quantiques présentant des canaux parallèles de conduction électroniques contrôlables in-situ. La température de l’électrode est mesurée très précisément à partir des fluctuations de courant électriques associées. La conductance thermique est alors déduite du ratio entre la puissance injectée et la différence de température. Pour observer le blocage de Coulomb de la chaleur, il a fallu refroidir à l’extrême le circuit afin que seuls les canaux de conduction électronique évacuent la chaleur. 

     

    Figure 1: Image en fausse couleur au microscope électronique de l’échantillon utilisé lors de la mesure du blocage de Coulomb de la chaleur. Les conducteurs quantiques sont réalisés dans la zone colorée en bleu et contrôlés par les pistes colorées en jaune. L’électrode métallique chauffée est coloriée en marron, des canaux de conduction sont symbolisés par les lignes rouges.


  • 16

    12/2016

    Efficient light trapping in ultrathin silicon solar cells


      Stéphane COLLIN.

    Ultrathin c-Si solar cells have the potential to drastically reduce costs by saving raw material, while maintaining good efficiencies thanks to the excellent quality of monocrystalline silicon. However, efficient light trapping strategies must be implemented to achieve high short-circuit currents. We report on the fabrication of both planar and patterned ultrathin c-Si solar cells on glass using low temperature (T<275°C), low-cost and scalable techniques. Epitaxial c-Si layers are grown by PECVD at 160°C and transferred on a glass substrate by anodic bonding and mechanical cleavage. A silver back mirror is combined with a front texturation based on an inverted nanopyramid array fabricated by nanoimprint lithography and wet etching. We demonstrate a short-circuit current density of 25.3 mA/cm² for an equivalent thickness of only 2.75µm. External quantum efficiency (EQE) measurements are in very good agreement with FDTD simulations. We infer an optical path enhancement of 10 in the long wavelength range. A simple propagation model reveals that the low photon escape probability of 25% is the key factor in the light trapping mechanism. The main limitations of our current technology and the potential efficiencies achievable with contact optimization are discussed. Reference: Ultrathin epitaxial silicon solar cells with inverted nanopyramid arrays for efficient light trapping, A. Gaucher, A. Cattoni, C. Dupuis, W. Chen, R. Cariou, M. Foldyna, L. Lalouat, E. Drouard, C. Seassal, P. Roca i Cabarrocas and S. Collin, Nano Letters 16, 5358–5364 (2016). http://pubs.acs.org/doi/abs/10.1021/acs.nanolett.6b01240

  • 16

    12/2016

    Bi-periodic nanostructured waveguides for wavelength-selectivity of hybrid photonic devices


      Anne TALNEAU.

    A bi-periodic nanostructuration consisting of a super-periodicity added to a nanohole lattice of sub-wavelength pitch is demonstrated to provide both modal confinement and wavelength selectivity within a hybrid III-V on Silicon waveguide. The wavelength selective behavior stems from finely-tuned larger holes. Such bi-periodic hybrid waveguides have been fabricated by oxide-free bonding III-V material on Silicon and display well defined stopbands. Such nanostructured waveguides offer the versatility for designing advanced optical functions within hybrid devices. Moreover, keeping the silicon waveguide surface planar, such nanostructured waveguides are compatible with electrical operation across the oxide-free hybrid interface. http://dx.doi.org/10.1364/OL.40.005148

  • 16

    12/2016

    Exchange interaction-driven dynamic nuclear polarization in Mn-doped InGaAs/GaAs quantum dots


      Olivier KREBS.

    The optical spin orientation and subsequent dynamic nuclear polarization (DNP) in individual self-assembled InGaAs/GaAs quantum dots doped by a single Mn atom is shown to be strongly perturbed by the exchange interaction between a photo-created electron and the spin of the magnetic impurity. The anisotropic part of the exchange, if strong enough , significantly depolarizes the electron spin in moderate magnetic fields, preventing thus any DNP. Yet, for small anisotropies, a pronounced DNP develops in an external magnetic field and shows a remarkable succession of rises interrupted by abrupt falls (evidenced by spectral jumps in the magneto-PL image). This striking behavior reveals the contribution of the exchange interactions to the energy cost of electron-nucleus spin flip-flops which drives the DNP efficiency. http://journals.aps.org/prb/abstract/10.1103/PhysRevB.94.195412

  • 16

    12/2016

    Lasers à microdisque sur silicium fonctionnant dans l’ultra-violet profond


      Philippe BOUCAUD.

    Un consortium constitué du L2C, CRHEA, CEA-Inac et C2N a fait la démonstration de lasers à microdisque fonctionnant à température ambiante dans l’ultra-violet profond. L’originalité de ces lasers est d’être constitués d’une couche active très fine en matériau III-N directement épitaxiée sur substrat silicium. Ceci permet de fabriquer simplement des microrésonateurs (microdisques, cristaux photoniques) de faible épaisseur (< 100 nm) avec de forts facteurs de qualité. En variant la composition de la zone active, on peut ajuster la longueur d’onde d’émission des lasers de 275 nm à 470 nm. http://www.cnrs.fr/inp/spip.php?article4581 "Deep-UV nitride-on-silicon microdisk lasers" J. Sellés, C. Brimont, G. Cassabois, P. Valvin, T. Guillet, I. Roland, Y. Zeng, X. Checoury, P. Boucaud, M. Mexis, F. Semond, B. Gayral Nature Scientific Reports 6, 21650 (2016) www.nature.com/articles/srep21650 "Near-infrared III-nitride-on-silicon nanophotonic platform with microdisk resonators" I. Roland, Y. Zeng, X. Checoury, M. El Kurdi, S. Sauvage, C. Brimont, T. Guillet, B. Gayral, M. Gromovyi, J. Y. Duboz, F. Semond, M. P. de Micheli, and P. Boucaud Optics Express 24, 9602 (2016) https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-9-9602

  • 15

    12/2016

    Flexible nitride nanowires light emitting diodes


      Maria TCHERNYCHEVA.

    Presently, flexible light sources mainly use organic materials integrated on lightweight and flexible plastic substrates. However, organic LEDs present a much lower luminance and a shorter lifetime in comparison to the LEDs based on inorganic nitride semiconductors. The inorganic semiconductor devices in their bulk form are mechanically rigid. Polymer-embedded nanowires (NWs) offer an elegant solution to create flexible optoelectronic devices, which combine the high efficiency and the long lifetime of inorganic semiconductor materials with the high flexibility of polymers. In our recent work we have fabricated NW light emitters, which can sustain large deformations. NW arrays embedded in a flexible film and lifted-off from their native substrate were contacted with a silver NW mesh. The lift-off and transfer procedure enables the assembly of free-standing layers of NW materials with different bandgaps without any constraint related to lattice-matching or growth conditions compatibility [1]. This concept therefore allows for a large design freedom and modularity since it enables combination of materials with very different physical and chemical properties, which cannot be achieved by monolithic growth. NW membranes with different properties were assembled in a two-color LED [1]. Combined with nano-phosphors, white flexible LEDs were demonstrated [2]. Lien web (si disponible): [1] http://pubs.acs.org/doi/full/10.1021/acs.nanolett.5b02900 [2] http://pubs.acs.org/doi/abs/10.1021/acsphotonics.5b00696

  • 15

    12/2016

    Flexible nitride nanowires light emitting diodes


      Maria TCHERNYCHEVA.

    Presently, flexible light sources mainly use organic materials integrated on lightweight and flexible plastic substrates. However, organic LEDs present a much lower luminance and a shorter lifetime in comparison to the LEDs based on inorganic nitride semiconductors. The inorganic semiconductor devices in their bulk form are mechanically rigid. Polymer-embedded nanowires (NWs) offer an elegant solution to create flexible optoelectronic devices, which combine the high efficiency and the long lifetime of inorganic semiconductor materials with the high flexibility of polymers. In our recent work we have fabricated NW light emitters, which can sustain large deformations. NW arrays embedded in a flexible film and lifted-off from their native substrate were contacted with a silver NW mesh. The lift-off and transfer procedure enables the assembly of free-standing layers of NW materials with different bandgaps without any constraint related to lattice-matching or growth conditions compatibility [1]. This concept therefore allows for a large design freedom and modularity since it enables combination of materials with very different physical and chemical properties, which cannot be achieved by monolithic growth. NW membranes with different properties were assembled in a two-color LED [1]. Combined with nano-phosphors, white flexible LEDs were demonstrated [2]. [1] http://pubs.acs.org/doi/full/10.1021/acs.nanolett.5b02900 [2] http://pubs.acs.org/doi/abs/10.1021/acsphotonics.5b00696

  • 9

    12/2016

    le C2N est un partenaire du réseau Européen NFFA pour la nanofabrication


      C2N.

    le C2N est un partenaire du réseau Européen NFFA pour la nanofabrication

  • 1

    12/2016

    ERC Consolidator HYPNOTIC (Hybrid Indium Phosphide on Silicon nanophotonics for ultimate laser diode


      Fabrice Raineri.

    The HYPNOTIC project aims at achieving a breakthrough in Silicon laser science and technology by taking forward the III-V semiconductors on Silicon hybrid technology into the nanophotonic world to make the dream of the convergence of microelectronics and photonics on a chip come true. This project intends to take up the challenge of bringing to reality electrically powered photonic crystal nanolasers as reference sources for dense integration and logical processing in a Silicon-based optical platform by accomplishing: (i) power efficiency with extremely low activation energies of few fJ, (ii) high bandwidth beyond 40Gbits/s, (iii) compactness with footprints less than 100µm² for high integration density of 103-104 of devices per mm2. A paradigm change will be brought to Silicon photonics by laying down 3 corner stones which consist firstly in the realisation of ultimate nanolaser diode sources at telecom wavelengths using an optimised single hybrid active nanocavity. Secondly, the groundbreaking atomic physics concepts of superradiance and lasing without inversion of population resonators will be transposed to nanophotonics by coupling several active nanocavities. Besides studying them for their fundamental interest, the project will capitalise on them to drastically augment the power efficiency and the modulation bandwidth of the nanosources. Finally, the fabricated nanolaser diodes using these novel concepts will be exploited to demonstrate cutting-edge flip-flop and memory devices able to surpass current off-chip electronic random access memories in access times and bandwidth which could enable unprecedented computational power.

  • 16

    11/2016

    Remise de prix pour le projet GOSPEL


      Delphine MORINI.

    Delphine Morini s'est vu décernée le Prix de l'impact sociétal de l' ANR pour le projet GOSPEL: PROPRIÉTÉS OPTIQUES LIÉES À LA BANDE INTERDITE DIRECTE DANS LES MULTI-PUITS QUANTIQUES Ge/SiGe

  • 16

    11/2016

    GOsPEL project awarded from the Societal impact Prize from the Research National Agency ANR (2016)


      delphine MORINI.

    In the information age, the reduction of the power consumption of information systems, and especially in the data centers will have major impact. The development of high data rate and low power consumption optical links to replace electrical interconnects is among the main challenges in silicon photonics. In this context, the GOsPEL project aimed at the demonstration of new optical integrated platforms based on Ge/SiGe quantum wells. This project tackled both the theoretical and experimental study of physical properties of quantum well structure and the demonstration of high performance photonic devices. Among the main results, a compact (< 100 µm) and low power consumption (<100 fJ/bit) optical modulator was obtained, and an optical link on a chip was demonstrated. This last result, published in Nature Photonics, showed the potential of these structures as innovative and powerful low power consumption optical platform. This project was awarded from the Societal impact Prize during the “Rencontres du numérique de l’ANR” on 16-17 November 2016.

  • 28

    06/2016

    June 28th 2016 – Laying of the cornerstone of C2N


      Giancarlo Faini.

    The ceremony of the laying of the cornerstone of C2N will take place on June 28th 2016, in the presence of Thierry Mandon, State Secretary at the Ministry for Education, Higher Education and Research in charge of Higher Eduction and Research, Sylvie Retailleau, President of the University Paris-Sud, and of Alain Fuchs, President of the CNRS, Centre National de la Recherche Scientifique. This event will be the opportunity to unveil a model of « mastaba » representing the engineered structures designed to host the instruments that are the most sensitive to mechanical vibrations and require stringent conditions in terms of ground stability. https://www.universite-paris-saclay.fr/fr/actualite/premiere-pierre-du-centre-de-nanosciences-et-de-nanotechnologies

  • 20

    06/2016

    Contrôler la photoluminescence des nanotubes de carbone


      Frédérique Pierre.

    En déposant des nanotubes de carbone sur des micro-résonateurs en forme d’anneau, des chercheurs de l'Institut d'électronique fondamentale (IEF, CNRS/Université Paris-Sud) sont parvenus à contrôler finement la lumière émise par les nanotubes. Adaptés à des dispositifs complexes, cette technologie pourrait permettre de maitriser des futures applications dans les télécommunications optiques ou les circuits intégrés pour la microélectronique. Ces travaux sont publiés dans la revue Nanotechnology.

  • 2

    06/2016

    Conclusion of a cooperation agreement with the Korea Electronics Technology Institute


      Amanda Trepagny.

    On 2/6/2016, during the economic forum organized by the French Business Confederation (MEDEF) and the Federation of Korean Industries (FKI), a cooperation agreement was signed between the Paris Sud University, represented by its President Sylvie Retailleau, and the KETI (Korea Electronics Technology Institute).
    The conclusion of this agreement has been made possible, in particular due to the interest of KETI for the research activities undertaken by the team of Elie Lefeuvre in the C2N department of Microsystems and Nanobiofluidics. More details in the press release here.

  • 1

    06/2016

    Birth of C2N


      Giancarlo Faini.

    Established on June 1st 2016, the Center for Nanosciences and Nanotechnologies (C2N) was launched in the wake of the joint CNRS and Université Paris-Sud decision to merge and gather on the same campus site the Laboratory for Photonics and Nanostructures (LPN) and the Institut d’Electronique Fondamentale (IEF). Its location on the École Polytechnique district of the Paris-Saclay campus, will be completed in 2017, the new C2N buildings being under construction.

  • 1

    06/2016

    Coherent control of an artificial atom with few photons


      Pascale SENELLART.

    In an optical quantum network, the information is transferred from one node to an other through light. A possible building block for such quantum network is an atom in a cavity. Ideally, every photon sent on the node should interact with the atom. Researchers at C2N, in collaboration with Institut Néel (Grenoble, France) have demonstrated the coherent control of an artificial atom with few photons. The quantum node here is a semiconductor quantum dot deterministically positioned in a microcavity. The results also show that, the same measurement performed with single photon Fock state of light, would allow inverting the atom state with 55% probability. These results are published in Nature Communications (open access). http://www.nature.com/ncomms/2016/160617/ncomms11986/full/ncomms11986.html

  • 24

    03/2016

    Jacqueline Bloch lauréate du Prix Jean Ricard


      Jacqueline Bloch.

    Le 24 mars dernier, Jacqueline Bloch a reçu des mains de Michel Spiro, président de la Société française de physique, le prix Jean Ricard 2016, qui récompense le remarquable travail effectué et qu’elle poursuit au sein du LPN à Marcoussis, dans le domaine de la spectroscopie des nanostructures semi-conductrices, de l’optique non-linéaire et de l’optique quantique. http://www.cnrs.fr/inp/spip.php?article4447 https://www.sfpnet.fr/laureate-du-prix-jean-ricard-2015-jacqueline-bloch

  • 1

    03/2016

    Near optimal single photon sources in the solid-state


      Pascale SENNELLART.

    Researchers at C2N, in collaboration with Institut Néel (Grenoble, France) and University of Queensland (Australia), have fabricated single photon sources based on semiconductor quantum dots of unprecedented quality. They succeeded in combining a unique technique invented in 2008 to position a quantum dot at the center of a micropillar acting as an optical cavity and an electrical control to remove the charge noise. They demonstrated the controlled and reproducible fabrication of bright sources of single photons that are nearly identical (to more than 99.5%). Their work shows that, compared to current technologies, these sources are about 15 times brighter than the heralded single photon sources based on frequency conversion. These results, published in Nature Photonics, open many perspectives for the optical quantum technologies. http://www.nature.com/nphoton/journal/v10/n5/full/nphoton.2016.23.html