The magnetoelectrochemical switch

In the field of spintronics, the archetype solid-state two-terminal device is the spin valve, where the resistance is controlled by the magnetization configuration. We show here how this concept of spin-dependent switch can be extended to magnetic electrodes in solution, by magnetic control of their chemical environment. Appropriate nanoscale design allows a huge enhancement of the magnetic force field experienced by paramagnetic molecular species in solutions, which changes between repulsive and attractive on changing the electrodes' magnetic orientations. Specifically, the field gradient force created within a sub-100-nm-sized nanogap separating two magnetic electrodes can be reversed by changing the orientation of the electrodes' magnetization relative to the current flowing between the electrodes. This can result in a breaking or making of an electric nanocontact, with a change of resistance by a factor of up to 103. The results reveal how an external field can impact chemical equilibrium in the vicinity of nanoscale magnetic circuits

Nanotrench for nano and microparticle electrical interconnects

We present a simple and versatile patterning procedure for the reliable and reproducible fabrication of high aspect ratio (10 4 ) electrical interconnects that have separation distances down to 20 nm and lengths of several hundreds of microns. The process uses standard optical lithography techniques and allows parallel processing of many junctions, making it easily scalable and industrially relevant. We demonstrate the suitability of these nanotrenches as electrical interconnects for addressing micro and nanoparticles by realizing several circuits with integrated species. Furthermore, low impedance metal-metal low contacts are shown to be obtained when trapping a single metal-coated microsphere in the gap, emphasizing the intrinsic good electrical conductivity of the interconnects, even though a wet process is used. Highly resistive magnetite-based nanoparticles networks also demonstrate the advantage of the high aspect ratio of the nanotrenches for providing access to electrical properties of highly resistive materials, with leakage current levels below 1 pA. © 2010 IOP Publishing Ltd

Electronique moléculaire à l'échelle de 100 nm contrôlée par une excitation lumineuse

[...] Le but de cette thèse est de réaliser et caractériser des dispositifs d'électronique moléculaire dans les domaines de taille de 10 a 100 nm, permettant d'accéder aux propriétés électriques intrinsèques aux molécules, et montrant une fiabilité et un[etc...] In the midway between bulk organic electronics and single molecule devices, are molecular electronic devices in the size range of 10-100 nm. This thesis is mostly dedicated to investigate these intermediate size devices. We envision several key

Light-triggered molecular electronics in the 100 nm size range

[...] Le but de cette thèse est de réaliser et caractériser des dispositifs d’électronique moléculaire dans les domaines de taille de 10 a 100 nm, permettant d’accéder aux propriétés électriques intrinsèques aux molécules, et montrant une fiabilité et une bonne reproductibilité des propriétés de transport électrique.[...] Une première partie du travail de thèse a consisté à mettre en place le système de mesure et de visualisation de l’échantillon, en utilisant des techniques de microscopie optique pour caractériser et exciter l’échantillon par lumière visible. Nous présentons ensuite plusieurs stratégies de réalisations d’échantillons permettant de connecter des molécules de taille nanométrique à des électrodes séparées par des distances de plusieurs dizaines de nanomètres. Nous montrons deux exemples de molécules bistables, en indiquant deux stratégies différentes pour la réalisation bottom up. Nous montrons également des résultats novateurs de conductivité d’assemblages supramoléculaires, ouvrant la voie a la réalisation de dispositifs d’électronique moléculaire à l’échelle de 100 nm.[etc...] In the midway between bulk organic electronics and single molecule devices, are molecular electronic devices in the size range of 10-100 nm. This thesis is mostly dedicated to investigate these intermediate size devices. We envision several key advantages: (1) direct top-down nanofabrication tools can be used to fabricate reliable and reproducible interconnects in the 50 – 100 nm size range, (2) we can use bottom up fabrication methodologies to create molecular-based materials of size exceeding a few tens of nanometers, (3) by targeting devices where transport occurs though a significant number of molecules, we get access to average properties, with the advantage of studying more robust and reproducible samples, with expected environmental stability making ambient conditions measurements possible. Our ambition is to convince the reader that this mid-sized devices approach is promising, with high potentials. Our ambition is to provide a solid ground for molecular electronics devices realization, where reliability and results confidence are priorities. This explains why, all along this thesis, a large number of control experiments have been performed.[etc...]

Electronique moléculaire à l'échelle de 100 nm contrôlée par une excitation lumineuse

[...] Le but de cette thèse est de réaliser et caractériser des dispositifs d'électronique moléculaire dans les domaines de taille de 10 a 100 nm, permettant d'accéder aux propriétés électriques intrinsèques aux molécules, et montrant une fiabilité et une bonne reproductibilité des propriétés de transport électrique.[...] Une première partie du travail de thèse a consisté à mettre en place le système de mesure et de visualisation de l'échantillon, en utilisant des techniques de microscopie optique pour caractériser et exciter l'échantillon par lumière visible. Nous présentons ensuite plusieurs stratégies de réalisations d'échantillons permettant de connecter des molécules de taille nanométrique à des électrodes séparées par des distances de plusieurs dizaines de nanomètres. Nous montrons deux exemples de molécules bistables, en indiquant deux stratégies différentes pour la réalisation bottom up. Nous montrons également des résultats novateurs de conductivité d'assemblages supramoléculaires, ouvrant la voie a la réalisation de dispositifs d'électronique moléculaire à l'échelle de 100 nm.[etc...] In the midway between bulk organic electronics and single molecule devices, are molecular electronic devices in the size range of 10-100 nm. This thesis is mostly dedicated to investigate these intermediate size devices. We envision several key advantages: (1) direct top-down nanofabrication tools can be used to fabricate reliable and reproducible interconnects in the 50 100 nm size range, (2) we can use bottom up fabrication methodologies to create molecular-based materials of size exceeding a few tens of nanometers, (3) by targeting devices where transport occurs though a significant number of molecules, we get access to average properties, with the advantage of studying more robust and reproducible samples, with expected environmental stability making ambient conditions measurements possible. Our ambition is to convince the reader that this mid-sized devices approach is promising, with high potentials. Our ambition is to provide a solid ground for molecular electronics devices realization, where reliability and results confidence are priorities. This explains why, all along this thesis, a large number of control experiments have been performed.[etc...]

Janus Microspheres for Visual Assessment of Molecular Interconnects

International audienc

Photoconduction in [Fe(Htrz)₂(trz)](BF₄)*H₂O nanocrystals

Sub-micron-sized [Fe(Htrz)2(trz)](BF4)*H2O nanoparticles that exhibit a spin crossover transition are positioned between Au electrodes with sub-100 nm separation. After voltage poling, samples exhibit unexpected large conductivity, with photoconductance and photovoltaic behavior

Light triggered self-construction of supramolecular organic nanowires as metallic interconnects

International audienceThe construction of soft and processable organic material able to display metallic conduction properties—a large density of freely moving charges—is a major challenge for electronics. Films of doped conjugated polymers are widely used as semiconductor devices, but metallic-type transport in the bulk of such materials remains extremely rare. On the other hand, single-walled carbon nanotubes can exhibit remarkably low contact resistances with related large currents, but are intrinsically very difficult to isolate and process. Here, we describe the self-assembly of supramolecular organic nanowires between two metallic electrodes, from a solution of triarylamine derivative, under the simultaneous action of light and electric field triggers. They exhibit a combination of large conductivity values (>5 × 103 S m−1) and a low interface resistance (<2 × 10−4 Ω m). Moreover, the resistance of nanowires in series with metal interfaces systematically decreases when the temperature is lowered to 1.5 K, revealing an intrinsic metallic behaviour