Fabrication et caractérisation électrique de résistances à base de nanofils de silicium

International audienceCet article présente des travaux pratiques sur la réalisation et la caractérisation électrique de résistances fabriquées à partir de nanofils de silicium polycristallin synthétisés à partir d'outils lithographiques conventionnels de la technologie silicium. Les résistances sont fabriquées en salle blanche puis caractérisées électriquement par mesures I-V

Visible and near-infrared photo-detector combining polysilicon TFT and PbS quantum dots

Integrated photodetector in the telecommunication range, around 1.4μm, is useful in new devices combining optics and electronics. It can be more useful if it can detect such wavelength with high detectivity and high speed. Such photodetector was developed in this work using very simple process. It uses usual polysilicon TFT where PbS quantum dots (PbS-QDs) have been embedded in the gate insulator. PbS-QDs are mixed with SU8 photoresist and the mixed solution is deposited by spin-coating on the partially fabricated polysilicon TFT. After drying, the deposition forms a layer that is used as gate insulator in place of the usual SiO2 layer. This TFT combine the high sensitivity of Quantum Dots (QDs) with the good charge transfer provided by the transistor’s structure. The absorption spectrum of the present 5.58 nm diameter PbS-QDs shows a peak at 1350nm in the telecommunication range of wavelength. The photo-TFTs present a responsivity value of 13 A/W at this wavelength. The responsivity is 1800 A/W at 760nm. The detectivity values at IR wavelength can reach a very high value 1.0×1013 Jones for N-type TFT. The answer time to an optical pulse is only some tens ms. The photo-transistor fabrication is compatible with all the present microelectronics technologies and with new flexible electronics technology. It can be directly implemented in any process without too much change. Particularly its process can be made in the last step after the fabrication of ICs. Please click Additional Files below to see the full abstract

Interpreter Training in Spain: Past and Present

Este artículo aborda la formación en interpretación en las universidades españolas desde que se inició en 1979. Se analizan los problemas asociados con el contenido en Interpretación de la Licenciatura en Traducción e Interpretación, vigente hasta hace poco, tales como la inclusión en el plan de estudios de asignaturas obligatorias que pretendían formar en las técnicas de interpretación utilizadas en Interpretación de Conferencia sin contar con la garantía de que los estudiantes cumplieran otros prerrequisitos necesarios para iniciar la formación en este género de interpretación. En la actualidad se está implantando la nueva titulación de Grado, y las universidades disfrutan de más libertad en la confección de sus planes de estudios. El panorama ahora es muy variado. Numerosas universidades han reducido sus créditos obligatorios en interpretación, al tiempo que han aumentado los créditos optativos. Aún así, sigue habiendo bastantes universidades que incluyen créditos obligatorios en interpretación simultánea. Parece que los títulos de Máster no acaban de consolidarse y otros géneros de interpretación (aparte de la interpretación de conferencia) han entrado en el plan de estudios.This paper deals with interpreter training in Spanish universities since its onset in 1979. Problems associated with the interpreting component in the recently phased out Licenciatura (4 year undergraduate course) in Translation and Interpreting are analysed. Such problems included the presence of compulsory subjects in the main conference interpreting techniques, without other prerequisites for beginning this training being guaranteed. At the current time a new degree is being introduced in the framework of the EHEA (Grado, also a 4 year undergraduate course) which affords much more freedom to the universities in the design of their syllabus. The results are very varied. Many universities have reduced their compulsory credits in interpreting and now offer more optional credits. Despite this trend, there are still a significant number of universities with compulsory credits in simultaneous interpreting. Master’s Degrees seem to be having difficulties in becoming consolidated and new genres of interpretation (other than conference interpreting) are being included in degree programmes

Effect of doping on the modification of polycrystalline silicon by spontaneous reduction of diazonium salts

International audienceThe chemical modification of doped polycrystalline silicon materials (N+, N++ and P++) and silicon (1 0 0) and (1 1 1) used as references is investigated by spontaneous reduction of diazonium salts. The effectiveness of the grafting process on all polySi surfaces is shown by AFM and XPS analyses. The effect of substrate doping on the efficiency of the electrografting process is compared by using the thicknesses of the deposited organic films. For a better accuracy, two methods are used to estimate the thicknesses: XPS and the coupling of a O2 plasma etching with AFM measurement. Structural characteristics of the poly-Si films were investigated by Scanning Electron Microscopy and X-ray diffraction to find a correlation between the structure of the material and its reactivity. Different parameters that could have an impact on the efficiency of the grafting procedure are discussed. The observed differences between differently doped silicon surfaces is rather limited, this is in agreement with the radical character of the reacting species

Matrice Active à Diodes Electroluminescentes Organiques en Technologie Silicium Microcristallin

Dans ce papier, nous analysons pour la première fois les performances d'une intégration de transistors à e¤et de champs couches minces en silicium microcristallin (c-Si TFT) sur matrice active dédiés à la technologie émergeante des a¢ cheurs à diodes électroluminescentes organiques (OLED). Les résultats obtenus à partir de notre technique de dépôt ont permis d'obtenir une amélioration signicative de l''uniformité électrique de pixel à pixel en associant à la fois un circuit pixel simple et un procédé technologique efficace

SiGe derivatization by spontaneous reduction of aryl diazonium salts

International audienceGermanium semiconductors have interesting properties for FET-based biosensor applications since they possess high surface roughness allowing the immobilization of a high amount of receptors on a small surface area. Since SiGe combined low cost of Si and intrinsic properties of Ge with high mobility carriers, we focused the study on this particularly interesting material. The comparison of the efficiency of a functionalization process involving the spontaneous reduction of diazonium salts is studied on Si(1 0 0), SiGe and Ge semiconductors. XPS analysis of the functionalized surfaces reveals the presence of a covalent grafted layer on all the substrates that was confirmed by AFM. Interestingly, the modified Ge derivatives have still higher surface roughness after derivatization. To support the estimated thickness by XPS, a step measurement of the organic layers is done by AFM or by profilometer technique after a O2 plasma etching of the functionalized layer. This original method is well-adapted to measure the thickness of thin organic films on rough substrates such as germanium. The analyses show a higher chemical grafting on SiGe substrates compared with Si and Ge semiconductors

Electron deficient dicyanovinylene-ladder-type pentaphenylene derivative for n-type Organic Field Effect Transistors

International audienceA bridged pentaphenylene derivative functionalized with dicyanovinylene units LPP([double bond, length as m-dash]C(CN)2)2 has been designed, synthesized and characterized. The optical and electrochemical properties have been carefully studied through a combined experimental and theoretical approach and compared with those of two pentaphenylene derivatives bearing methylenes (LPP) or carbonyl (LPP([double bond, length as m-dash]O)2) on the bridgeheads. LPP([double bond, length as m-dash]C(CN)2)2 which possesses a very low LUMO level, ca. −4.02 eV, has been successfully used as an active layer in n-channel OFETs using the epoxy based photoresist SU-8 as a gate insulator. LPP([double bond, length as m-dash]C(CN)2)2 based n-channel OFETs show low voltage functioning (low gate-source and drain-source voltages), high ratio between the on and the off currents (2 × 105), interesting subthreshold swing (S = 1) and excellent stability under electrical stress and in a nitrogen atmosphere. More importantly, we have also shown that LPP([double bond, length as m-dash]C(CN)2)2 based n-channel OFETs present an excellent environmental stability. This work is to the best of our knowledge the first report on bridged pentaphenylene-based semiconductors in n-type OFETs and highlights the potential of such type of material to provide air stable OFETs

Problématique du coût d’une filière énergétique

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PolySi TFT to the Flexible Substrate

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Nano-Crystalline silicon based electronics on plastics and applications

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