Anne Pépin

• PhD
• Senior Policy Officer at European Commission

A “program” is an organized effort to improve delivery of a practice or service to a population. In the context of this volume, the central goal of programs is the participation of women (and girls) in a series of planned activities, which taken together, place or keep them on a path toward a science-based degree or career. To be sustained over tim...

d a Mission pour la place des femmes au CNRS, Centre National de la Recherche Scientifique (France), b Trinity College Dublin (Ireland), c Šiauliai University (Lithuania), d GESIS-Leibniz Institute for the Social Sciences (Germany) ABSTRACT This paper draws upon baseline evidence compiled for the FP7 Project "INstitutional Transformation for Effect...

This talk is intended to give an overview of research in Nanoscience and Nanotechnology (N&N) in France and especially at the French National Center for Scientific Research (CNRS), which has made research in N&N one of its five priorities. In the first part we list the main scientific issues at stake, as they were identified in a recent scientific...

Contains reports on twenty research projects and a list of publications.

Contains reports on the nanostructures laboratory, eighteen research projects and a list of publications.

We present statistics on the underrepresentation of females entering scientific studies and on the persistence of a glass ceiling for women physicists-and female scientists in general-in France. We also examine actions taken by French research institutions, associations, companies, and professional societies since 2005 to improve these situations.

We report on a mix-and-match method based on a combination of soft UV nanoimprint lithography, contact optical lithography, and reactive-ion-etch techniques, which is applicable for high throughput manufacturing of nanostructure integrated microfluidic devices. We demonstrate the integration of high density and high aspect ratio nanopillars into mi...

Soft UV nanoimprint lithography and reactive ion etch techniques have been used to pattern high density and high aspect ratio nanostructures on the surface of a plastic plate such as Plexiglas. A thin film of photo-curable resist is first spin coated on the plastic plate, with or without deposition of a 10nm thick germanium intermediate layer. Then...

Today, the microelectronics industry can produce transistors with features of critical size close to 100nm on 8-inch wafers. By developing new lithographic methods, such as extreme UV lithography, it will be possible to achieve a critical dimension around 20nm [35]. To reach still smaller sizes, a further technological breakthrough will be required...

Control of the establishment of cell polarity is an essential function in tissue morphogenesis and renewal that depends on spatial cues provided by the extracellular environment. The molecular role of cell–cell or cell–extracellular matrix (ECM) contacts on the establishment of cell polarity has been well characterized. It has been hypothesized tha...

Hydrodynamic dispersion in shallow microchannels with almost parabolic cross-sectional shapes and with heights much less than their widths is studied experimentally. Both long serpentine channels and rotary mixers are used. The experimental results demonstrate that the dispersion depends on the width rather than the height of the channel. The resul...

Cells display a large variety of shapes when plated in classical culture conditions despite their belonging to a common cell type. These shapes are transitory, since cells permanently disassemble and reassemble their cytoskeleton while moving. Adhesive micropatterns are commonly used to confine cell shape within a given geometry. In addition the mi...

Soft imprinting lithography assisted by UV light (soft UV-NIL) takes advantage of both, UV-nanoimprint and soft lithography. This technique, which can be applied for the replication of nanometer size features over large areas, is suitable for the patterning of nanostructures like photonic crystals with high throughput and high accuracy. In this wor...

Nanoimprint lithography assisted by ultraviolet photopolymerization through a soft elastomer-based mold is applied to the fabrication of silicon-on-insulator slab photonic crystals for optical wavelengths. Variable angular reflectance is used to measure the dispersion of the photonic leaky modes. Experimental results are in good agreement with both...

The cell division axis determines the future positions of daughter cells and is therefore critical for cell fate. The positioning of the division axis has been mostly studied in systems such as embryos or yeasts, in which cell shape is well defined. In these cases, cell shape anisotropy and cell polarity affect spindle orientation. It remains uncle...

The natural hydrophobicity of surfaces can be enhanced if they are micro-textured. This is due to air trapped in the structure, which provides the deposited drop with a composite surface made of solid and air on which it is resting. Here, we give evidence for this effect using a forest of micro-pillars which allows us to control the micro structure...

We report on experiments demonstrating the possibility to pump electrolyte solutions in closed microchannel loops using asymmetric arrays of micro-electrodes addressed with AC voltages. Velocities of a few mm/s can be obtained with voltages of a few Volts in this integrable pumping scheme. The variation of pumping velocity with frequency, amplitude...

We report a detailed study of a low voltage AC electrokinetic micropump, performed in a dedicated microfluidic chip. The micropump consists of an array of interdigitated micro-electrodes and is integrated in a closed microfluidic loop. We show that such a device pumps continuously and reproducibly at velocities up to 500 mu m/s in 20 mu m-deep and...

We have built a dedicated lab on a chip to study the performance of an integrated electrokinetic micropump, driven by a low voltage AC signal. This micropump consists of an array of interdigitated electrodes and is here integrated in a microfluidic loop. We demonstrate that this device can pump continuously and reproducibly electrolyte solutions of...

We report on the development of microfluidic devices for single mammalian cell sorting and manipulation. These microfluidic devices are fabricated out of polydimethylsiloxane (PDMS) by multilayer soft lithography. They consist of several active units (mixer, pumps) pneumatically actuated by monolithic soft microvalves. Using this fabrication method...

We have explored the feasibility of using negative epoxy novolak-based SU-8 2002 resist as an electron beam lithography resist for ultra high speed fabrication of large areas of high resolution patterns. 75 nm-wide lines have been obtained in thin-layered SU-8 films, using a 50 keV electron beam system, and the required exposure dose was found to b...

We have explored the feasibility of using negative epoxy novolak-based SU-8 2002 resist as an electron beam lithography resist for ultra high speed fabrication of large areas of high resolution patterns. 75 nm-wide lines have been obtained in thin-layered SU-8 films, using a 50 keV electron beam system, and the required exposure dose was found to b...

Considerable efforts are currently under way to construct microfluidic devices for advanced chemical and biological applications. We have developed a dynamic imaging tool that enables visualisation of microflows in various geometries. Streamlines were obtained by recording a sequential image of particle positions, for example those of fluorescent o...

In the past decade, microfabrication has become increasingly important to biology and biomedical applications. The fabrication techniques initially developed for the microelectronics industry, e.g. photolithography and associated material processing, along with the silicon micromachining methods later developed for micro-electromechanical systems (...

Two techniques for the fabrication of novel microfluidic devices for electrokinetic fluid pumping are presented. Both consist of forming a micro-channel and reservoirs on a transparent cover sheet and patterning an array of interdigitated asymmetric micro-electrodes on a flat substrate. The two techniques differ from each other in their building ma...

We describe the fabrication of microfluidic devices for bio-molecule separation using an array of well-defined nanostructures. Two types of pattern replication of the same device configuration are considered, based on different material processing. In the first approach we use a tri-layer nanoimprint lithography process to pattern a silicon dioxide...

We demonstrate that room-temperature and low-pressure nanoimprint lithography techniques can be achieved by using Hybrane HS2550, a semi-crystalline hyperbranched resist polymer with a glass transition temperature below and a melting point above room temperature. Nanoimprint lithography at room temperature is possible with sub-100 nm resolution, as...

We present a method for the fabrication of plastic microfluidic devices based on nanoembossing and thermal bonding. By nanoembossing of thermoplastic polymer pellets, both microfluidic deep channels and high resolution features can be formed using a silicon mold fabricated by electron beam lithography and reactive ion etching. By thermal bonding wi...

Micron/nano scale Co dot and wire arrays have been fabricated by soft lithography patterning with a resolution of 100nm. Magneto-optic Kerr effect magnetometry combined with micromagnetic calculation is used to study, in detail, the vortex-single domain transition in the Co dots. A metastable single-domain state, which is stabilized by a local mini...

Nanofabrication is playing an ever increasing role in science and technology on the nanometer scale and will soon allow us to build systems of the same complexity as found in nature. Conventional methods that emerged from microelectronics are now used for the fabrication of structures for integrated circuits, microelectro-mechanical systems, microo...

Replication of patterns at a nanometer scale is a challenge for both advanced optical lithography and post-optical techniques. Considerable industrial effort has been devoted to the so-called leading-edge optical methods and the next generation lithography techniques. In parallel, a number of low-cost techniques such as nanoimprint and micro-con...

We present our results in the design and development of a multiple-beam x-ray pattern generator based on an array of Fresnel zone plates (FZPs). Exposures have been carried out using a synchrotron source at SuperACO (France), a PC-controlled piezoelectric scanning stage, and an array of FZPs fabricated by high resolution electron-beam lithography a...

We report on the resolution limits of Electron Beam Lithography (EBL) in the conventional polymethylmethacrylate (PMMA) organic resist. We show that resolution can be pushed below 10 nm for isolated features and how dense arrays of periodic structures can be fabricated at a pitch of 30 nm, leading to a density close to 700 Gbit/in2. We show that in...

The fabrication of a lateral single electron memory (LSEM) based on the integration of a metallic multiple tunnel junction (MTJ) and a memory node (MN) on a Si metal oxide semiconductor field effect transistor (MOS) has been investigated. High resolution electron beam lithography (HREBL) was used to fabricate devices presenting good morphological c...

Nanometer-sized multijunction arrays are expected to exhibit a large Coulomb blockade effect. However, up to now, only highly disordered arrays can be fabricated. In this article, we evaluate the consequences of disorder on the dispersion of the device characteristics. We show that, as observed for regular arrays, the threshold voltage Vth increase...

The temperature behavior of multiple tunnel junction (MTJ) devices made with sub-5-nm gold islands is investigated. A smooth decrease of the Coulomb gap with increasing temperatures is observed. The critical temperature beyond which the Coulomb blockade effect is suppressed is found to change as a function both of the average size of the islands an...

The fabrication of two-dimensional multiple tunnel junction (MTJ) devices by deposition of Au droplets from a liquid metal ion source is reported. By adjusting the emission parameters of the source and the final landing voltage of the droplets we have been able to deposit 1 nm size islands with a good reproducibility and with a sufficient density t...

Coulomb blockade devices using wet coating with a colloidal Pd/Sn solution have been fabricated and characterised. The colloidal film was found to grow preferentially between the metallic contacts patterned on the sample surface. This preferential adsorption between the electrodes can lead to colloidal films of only one monolayer thick while in oth...

A reproducible fabrication method for Coulomb blockade devices which combines Electron Beam Lithography and granular gold film deposition is presented. The deposition parameters are optimised to produce gold grains of n nm diameter with distances between grains around 1 nm. Nanofabrication techniques developed to fully control the size of the dot a...

We measure the dissolution rate of poly(methylmethacrylate) (PMMA) as a function of height above substrates of silicon and thin films suitable as bases for gold electroplating: a “thick-gold” film (10 nm Ti/10 nm Au), and a “thin-gold” film (10 nm Ti/1.8 nm Au). For the thick-gold film, a dramatic increase is seen in the PMMA dissolution rate start...

Spatial selectivity of layer disordering induced in GaAs/AlGaAs quantum well heterostructures using SiO 2 and Si 3 N 4 capping and annealing was investigated using low temperature photoluminescence in conjunction with cross-sectional transmission electron microscopy. Comparative study reveals opposite behaviors for patterned Si 3 N 4 covered with S...

We have investigated intermixing enhancement in GaAs/AlGaAs quantum well heterostructures achieved by SiO2 capping obtained by rapid thermal chemical vapor deposition. Evidence of fast Ga pumping inside the SiO2 layer during anneal and simultaneous generation of excess Ga vacancies under the SiO2/GaAs interface is presented. A simple model involvin...

We demonstrate that selective intermixing of GaAs/AlGaAs quantum well heterostructures induced by SiO2 capping and subsequent annealing can be spatially localized on a length scale compatible with the lateral confinement of carriers into quantum wires. Low temperature optical spectroscopy measurements including linear polarization anisotropy analys...

Intermixing of GaAs/AlGaAs single quantum well heterostructures by SiO2 capping and subsequent annealing was investigated using low‐temperature photoluminescence. In this letter we report the observation of the conservation of splittings related to one‐monolayer thickness variations in the emission of quantum wells after an intermixing process. Hig...

We present experimental results on the selective interdiffusion of GaAs/GaAlAs quantum well heterostructures induced by SiO₂ and Si₃N₄ capping and annealing. Comparative studies show that interdiffusion occurs under SiO₂ in the case of patterned Si₃N₄ strips coated with SiO<sub>2</su...

Results are presented demonstrating that selective intermixing of GaAs/AlGaAs quantum well heterostructures by SiO2 capping and subsequent annealing can be spatially localized with a length scale compatible with the observation of lateral quantum confinement effects. Patterning of a 400 nm-thick SiO2 encapsulation layer deposited by rapid thermal c...

A new versatile procedure combining conventional lithography and focused ion beam coupled to scanning electron microscopy to micromachine high‐quality cross‐sectional transmission electron microscopy (TEM) samples is proposed. Electron transparent areas are generated with a high degree of localization, within 0.1 μm, over distances of several milli...

Two new productive techniques, one combining electron lithography and reactive ion etching and the other based on focused ion beam micromachining to thin high quality cross-sectional TEM samples are proposed. Electron transparent areas are generated with a high degree of localization, within 0.1 mu m, over distances of several mm in GaAs/GaAlAs het...

Intermixing of AlGaAs-based structures is known to be enhanced by capping samples with a layer of SiO2. Experiments on undoped single quantum well structures capped with rapid thermal chemical vapour deposition SiO2 performed by transmission electron microscopy in conjunction with low temperature photoluminescence indicated a strong, homogeneous in...

We present a novel approach to control internal organization and polarity of individual adherent cells in culture. To control cell adhesion, we used micro-contact printing with two basic features: 1) the proper adhesive surfaces for a given convex envelope were reduced in order to impose more stringent adhesive conditions than a fully adhesive patt...