All-electrical detection of the spin-charge conversion in nanodevices based on SrTiO3 two-dimensional electron gases

The Magnetoelectric Spin-Orbit (MESO) technology aims to bring logic into memory by combining a ferromagnet with a magnetoelectric (ME) element for information writing, and a spin-orbit (SO) element for information read-out through spin-charge conversion. Among candidate SO materials to achieve a large MESO output signal, oxide Rashba two-dimensional electron gases (2DEGs) have shown very large spin-charge conversion efficiencies, albeit mostly in spin-pumping experiments. Here, we report all-electrical spin-injection and spin-charge conversion experiments in nanoscale devices harnessing the inverse Edelstein effect of SrTiO3 2DEGs. We have designed, patterned and fabricated nanodevices in which a spin current injected from a cobalt layer into the 2DEG is converted into a charge current. We optimized the spin-charge conversion signal by applying back-gate voltages, and studied its temperature evolution. We further disentangled the inverse Edelstein contribution from spurious effects such as the planar Hall effect, the anomalous Hall effect or the anisotropic magnetoresistance. The combination of non-volatility and high energy efficiency of these devices could potentially lead to new technology paradigms for beyond-CMOS computing architectures

Room Temperature‐Integrated Photodetector between 5 μm and 8 μm Wavelength

Mid-infrared (mid-IR) optics has a great importance for a large number of applications in sensing, imaging, or even telecommunication. However, high-speed and room-temperature-integrated photodetector (PD) operating in a wide spectrum of the mid-IR is a critical device that is currently missing for the development of compact and efficient spectroscopic systems exploiting synchronous detection. Herein, a waveguide-integrated PD based on a Schottky diode embedded in a graded silicon germanium waveguide is demonstrated. Photodetection is obtained in a wide spectral range from 5 to 8 μm wavelength, with responsivity reaching up to 0.1 mA W−1. Photodetection performed in pulsed regime with laser pulse width between 50 and 200 ns indicates an operation beyond 20 MHz. Interestingly, the achieved performances indicate that this device is already suitable for on-chip signal monitoring, while further improvement can pave the way toward advanced compact and fully integrated spectroscopic systems operating in long-wave infrared regions

1 GHz electro-optical silicon-germanium modulator in the 5-9 µm wavelength range

: Spectroscopy in the mid-infrared (mid-IR) wavelength range is a key technique to detect and identify chemical and biological substances. In this context, the development of integrated optics systems paves the way for the realization of compact and cost-effective sensing systems. Among the required devices, an integrated electro-optical modulator (EOM) is a key element for advanced sensing circuits exploiting dual comb spectroscopy. In this paper, we have experimentally demonstrated an integrated EOM operating in a wide wavelength range, i.e. from 5 to 9 µm at radio frequency (RF) as high as 1 GHz. The modulator exploits the variation of free carrier absorption in a Schottky diode embedded in a graded silicon germanium (SiGe) photonic waveguide

Revisiting micro hot-embossing with moulds in non-conventional materials

International audienceManufacturing moulds in non-metallic tooling materials using non conventional structuring techniques is explored for rapid and/or alternative tooling for hot embossing of polymers. Some challenges and advantages of producing embossing tools by deep reactive ion etching (DRIE) in silicon and/or replica-casting in poly(dimethylsiloxane) (PDMS) and utilizing them in the replication process are highlighted

Design, development and applications of etched multilayers for soft X-ray spectroscopy

An etched multilayer, a 2D structure fabricated by etching a periodic multilayer according to the pattern of a laminar grating, is applied in the soft X-ray range to improve the spectral resolution of wavelength dispersive spectrometers. The present article gathers all the successive stages of the development of such a device optimized to analyze the characteristic emission of light elements: design, structural and optical characterization and applications to X-ray spectroscopy. The evolution of the shape of the C Kα emission band of highly oriented pyrolytic graphite (HOPG), as a function of the angle between the emission direction and the (0 0 0 1) planes, is measured. These results, compared to those with a grating, demonstrate that the achieved spectral resolution enables disentangling σ → 1s and π → 1s transitions within the C K emission band

Microfabricated silicon array of microneedles : prediction of its behaviour during insertion through the skin

Transdermal drug delivery is a novel alternative painless way to inject medicine and therapic agents through skin. Our study investigates an array of out-of-plane microneedles to pierce the permeability barrier without reaching the nerves in the deeper layers. To the best of our knowledge, the skin behavior during the insertion of a microneedle array through its different layers has not up to now been fully dealt with. In this paper, we assume skin to be similar to a stratified material, and approximate it as composed of three layers: the stratum corneum is described by a linear isotropic material model while a hyperelastic material model (Ogden) is used for the two deeper layers. The choice of the model is all the more important since we work at a microscopic scale. We prove that differences exist between the insertion of one microneedle and the insertion of an array of microneedles in terms of the skin deformation and value of the insertion force due to the interaction among microneedles. We simulate the insertion of a micro needles array using a finite element method and the results show a relation between the microneedle diameter, the array density and the microneedle length. Our arrays of microneedles are fabricated by deep reacting ion etching (DRIE) and coated by titanium out of biocompatibility concerns. In this paper, the dimensions of the microneedles are: 500 microns in length, 30-60 microns in inner channel diameter and 100-150 microns in outer diameter in order to be in agreement with our analytically analysis. Some experimental validations are given

Recent progress in GeSi electro-absorption modulators

Electro-absorption from GeSi heterostructures is receiving growing attention as a high performance optical modulator for short distance optical interconnects. Ge incorporation with Si allows strong modulation mechanism using the Franz–Keldysh effect and the quantum-confined Stark effect from bulk and quantum well structures at telecommunication wavelengths. In this review, we discuss the current state of knowledge and the on-going challenges concerning the development of high performance GeSi electro-absorption modulators. We also provide feasible future prospects concerning this research topic

Comparaison de procédés de lithographie, une initiative du groupe Euronanolab Lithographies

National audienceThe document presents the approach taken by the lithography expert group of the EUROnanoLAB network, which has 91 members in 14 countries and 40 academic laboratories. The aim of this initiative is to encourage technical and scientific exchanges on the various lithography techniques. We begin with a presentation of the EUROnanoLAB Lithography group and its various activities, such as the organisation of videoconferences and face-to-face meetings, staff exchanges and the establishment of databases on equipment and processes. Next, we detail the initiative centred on the comparison of lithography processes. Each participating laboratory tests a lithography process using a predefined design imposed on all. Two types of resin are tested: a 1 µm thick resist (+/-20%) and a 50 µm thick resist (+/-20%). Participants must achieve the best results based on criteria such as resolution, verticality of resin profiles, aspect ratio, exposure time and ease of processing. Laboratories have a choice of resins, polarity and techniques (contact lithography, stepper, electronic, laser, etc.), as well as equipment. The aim of this presentation is to provide participants with an in-depth understanding of the different lithography techniques, to help them choose the methods best suited to their specific projects. By sharing the knowledge and experience of the members of the EUROnanoLAB group, this initiative hopes to foster increased collaboration and continued innovation in the field of lithography.Le document présente une démarche du groupe d'experts lithographie du réseau EUROnanoLAB, qui compte 91 membres répartis dans 14 pays et 40 laboratoires académiques. Cette initiative vise à encourager les échanges techniques et scientifiques autour des différentes techniques de lithographie. Nous débutons par une présentation du groupe EUROnanoLAB Lithographies et de ses diverses actions, telles que l'organisation de rencontres en visioconférences ou en présentiel, les échanges de personnels, et l'établissement de bases de données sur les équipements et procédés.Ensuite, nous détaillons l'initiative centrée sur la comparaison des procédés de lithographie. Chaque laboratoire participant teste un procédé de lithographie en utilisant un design prédéfini et imposé à tous. Deux types de résines sont testés : une résine de 1 µm d'épaisseur (+/-20%) et une résine de 50 µm d'épaisseur (+/-20%). Les participants doivent obtenir les meilleurs résultats en fonction de critères tels que la résolution, la verticalité des profils de résine, le rapport de forme, le temps d'exposition et la facilité de mise en œuvre. Les laboratoires ont le choix des résines, de la polarité et des techniques utilisées (lithographie par contact, stepper, électronique, laser, etc.), ainsi que des équipements. Cette présentation a pour objectif d'offrir aux participants une compréhension approfondie des différentes techniques de lithographie, afin de les aider à choisir les méthodes les plus adaptées à leurs projets spécifiques. En partageant les connaissances et les expériences des membres du groupe EUROnanoLAB, cette initiative espère favoriser une collaboration accrue et une innovation continue dans le domaine de la lithographie

Comparaison de procédés de lithographie, une initiative du groupe Euronanolab Lithographies

National audienceThe document presents the approach taken by the lithography expert group of the EUROnanoLAB network, which has 91 members in 14 countries and 40 academic laboratories. The aim of this initiative is to encourage technical and scientific exchanges on the various lithography techniques. We begin with a presentation of the EUROnanoLAB Lithography group and its various activities, such as the organisation of videoconferences and face-to-face meetings, staff exchanges and the establishment of databases on equipment and processes. Next, we detail the initiative centred on the comparison of lithography processes. Each participating laboratory tests a lithography process using a predefined design imposed on all. Two types of resin are tested: a 1 µm thick resist (+/-20%) and a 50 µm thick resist (+/-20%). Participants must achieve the best results based on criteria such as resolution, verticality of resin profiles, aspect ratio, exposure time and ease of processing. Laboratories have a choice of resins, polarity and techniques (contact lithography, stepper, electronic, laser, etc.), as well as equipment. The aim of this presentation is to provide participants with an in-depth understanding of the different lithography techniques, to help them choose the methods best suited to their specific projects. By sharing the knowledge and experience of the members of the EUROnanoLAB group, this initiative hopes to foster increased collaboration and continued innovation in the field of lithography.Le document présente une démarche du groupe d'experts lithographie du réseau EUROnanoLAB, qui compte 91 membres répartis dans 14 pays et 40 laboratoires académiques. Cette initiative vise à encourager les échanges techniques et scientifiques autour des différentes techniques de lithographie. Nous débutons par une présentation du groupe EUROnanoLAB Lithographies et de ses diverses actions, telles que l'organisation de rencontres en visioconférences ou en présentiel, les échanges de personnels, et l'établissement de bases de données sur les équipements et procédés.Ensuite, nous détaillons l'initiative centrée sur la comparaison des procédés de lithographie. Chaque laboratoire participant teste un procédé de lithographie en utilisant un design prédéfini et imposé à tous. Deux types de résines sont testés : une résine de 1 µm d'épaisseur (+/-20%) et une résine de 50 µm d'épaisseur (+/-20%). Les participants doivent obtenir les meilleurs résultats en fonction de critères tels que la résolution, la verticalité des profils de résine, le rapport de forme, le temps d'exposition et la facilité de mise en œuvre. Les laboratoires ont le choix des résines, de la polarité et des techniques utilisées (lithographie par contact, stepper, électronique, laser, etc.), ainsi que des équipements. Cette présentation a pour objectif d'offrir aux participants une compréhension approfondie des différentes techniques de lithographie, afin de les aider à choisir les méthodes les plus adaptées à leurs projets spécifiques. En partageant les connaissances et les expériences des membres du groupe EUROnanoLAB, cette initiative espère favoriser une collaboration accrue et une innovation continue dans le domaine de la lithographie

Ge-rich silicon germanium as a new platform for optical interconnects on silicon

We propose germanium-rich silicon-germanium (SiGe) as a new platform for optical interconnects. The platform viability is experimentally and theoretically investigated through the realization of main building blocks of passive circuitry. Germanium-rich Si1-xGex guiding layer on a graded SiGe layer is used to experimentally show 12μm radius bends by light confinement tuning at a wavelength of 1550nm. As a next step, Mach Zehnder interferometer with 10 dB extinction ratio is demonstrated. High Ge content of the proposed platform allows the coupling with Ge-based active devices, relying on a high quality epitaxial growth. Hence, the integration on Silicon of high speed and low power consumption Ge-rich active components is possible, despite the high lattice mismatch between silicon and germanium