Bibliografie tematiche / Films de silice

Letteratura scientifica selezionata sul tema "Films de silice"

Autore: Grafiati

Pubblicato: 8 giugno 2024

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Articoli di riviste sul tema "Films de silice":

Bouchard, H., A. Azelmad, J. F. Currie e M. Meunier. "Variation de la contrainte des verres de silice sous cycle thermique". Canadian Journal of Physics 70, n. 10-11 (1 ottobre 1992): 830–33. http://dx.doi.org/10.1139/p92-131.

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Using an in situ technique, stress was measured as a function of annealing temperature to investigate the effect of phosphorous and boron doping of silicon dioxide glass films deposited by low-pressure chemical vapor deposition (LPCVD). It was found that the initial stress of phosphosilicate glass is independent of the amount of phosphorus present, while the boron content influences the initial stress in borophosphosilicate glass. The stress increases to a maximum, σm, corresponding to a temperature Tm, above which the onset of viscous flow reduces the stress to zero at a temperature T0. All these parameters are dependant on dopant concentrations. The observed mechanical behavior is discussed in terms of film viscosity.

Bahlawane, N., M. Charbonnier e M. Romand. "Apport des techniques XRFS et LEEIXS à l'étude de la formation de films de silice sur acier par PACVD". Le Journal de Physique IV 08, PR5 (ottobre 1998): Pr5–271—Pr5–278. http://dx.doi.org/10.1051/jp4:1998534.

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Balan, Poovarasi, Aaron Ng, Chee Beng Siang, R. K. Singh Raman e Eng Seng Chan. "Effect of Nanoparticle Addition in Hybrid Sol-Gel Silane Coating on Corrosion Resistance of Low Carbon Steel". Advanced Materials Research 686 (aprile 2013): 244–49. http://dx.doi.org/10.4028/www.scientific.net/amr.686.244.

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Chromium pre-treatments of metal have been replaced by silane pre-treatments as more environmental friendly option. Nanoparticles can be added in the silane sol-gel network have been reported to improve corrosion resistance. In this work, the electrochemical corrosion resistance of low carbon steel coated with hybrid organic-inorganic sol-gel film filled with nanoparticles was evaluated. The sol-gel films have been synthesized from 3-glycidoxy-propyl-trimethoxy-silane (3-GPTMS) and tetra-ethyl-ortho-silicate (TEOS) precursors. These films have been impregnated with 300 ppm of silica or alumina nanoparticles. The electrochemical behavior of the coated steel was evaluated by means of electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Equivalent circuit modeling, used for quantifying the EIS measurements showed that sol-gel films containing silica nanoparticles improved the barrier properties of the silane coating. The silica nanoparticle-containing films showed highest initial pore resistance over the five days of immersion in 0.05M NaCl.

Park, Hoy Yul, Dong Pil Kang, In Hye Myung e Seog Young Yoon. "Properties of Coating Films Synthesized from Nano Colloidal Silica and Alkoxy Silanes". Materials Science Forum 510-511 (marzo 2006): 222–25. http://dx.doi.org/10.4028/www.scientific.net/msf.510-511.222.

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Colloidal silica/silane sol solutions were prepared in variation with the ratio of silane to colloidal silica. Such sol solutions were synthesized from colloidal silica/tetramethoxysilane (TMOS)/methyltrimethoxysilane(MTMS). Sol solutions were prepared by sol-gel reaction through two step reactions. To understand their physical and chemical properties, dip coating of sol solutions was performed on the glass substrates. Contact angle and thickness of coating films increased with increasing the amount of MTMS. The surface free energy of coating films decreased with increasing amount of MTMS. Coating films were stable until 550°C. Thermal degradation temperature of coating films decreased with increasing amount of MTMS. Plastic hardness decreased with increasing amount of MTMS. Elastic portion increased with increasing amount of MTMS.

Tao, Yao, Feng Zheng, Zhao Chen, Shuangshuang Chen, Xuemin Lu e Qinghua Lu. "Comparison of hybrid polyimide films with silica and organosilica obtained via sol–gel process". High Performance Polymers 29, n. 9 (14 settembre 2016): 1049–57. http://dx.doi.org/10.1177/0954008316668242.

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A series of polyimide/silica (PI–S) and polyimide/organosilica (PI–OS) hybrid films were prepared via a sol–gel process from mixtures of poly(amic acid) (PAA) and tetraethoxysilane or a silane coupling agent in solution. The PAA was synthesized from bis-(3-phthalyl anhydride) ether and 1,4-bis (4-aminophenoxy) benzene. The hybrid films were produced via an imidization reaction to form silica particles or a silica network in a polymer matrix through a programmed heating process. The derived films were characterized and compared by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, thermogravimetric analysis, tensile testing, contact angle measurements, moisture absorption measurements, and dielectric property analysis. Both the PI–S and PI–OS hybrid matrixes showed strong regularity with the increasing silica content and greatly improved thermal stability and mechanical properties. Among them, the PI–OS hybrid films possessed superior interphase interactions and were found to have better physicochemical properties.

Jiang, Pei-Cheng, Yu-Ting Chow, Chi-Wei Chien, Cheng-Hsun-Tony Chang e Chii-Ruey Lin. "Silica Layer Used in Sensor Fabrication from a Low-Temperature Silane-Free Procedure". Chemosensors 9, n. 2 (4 febbraio 2021): 32. http://dx.doi.org/10.3390/chemosensors9020032.

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Silica (SiO2, silicon dioxide—a dielectric layer commonly used in electronic devices) is widely used in many types of sensors, such as gas, molecular, and biogenic polyamines. To form silica films, core shell or an encapsulated layer, silane has been used as a precursor in recent decades. However, there are many hazards caused by using silane, such as its being extremely flammable, the explosive air, and skin and eye pain. To avoid these hazards, it is necessary to spend many resources on industrial safety design. Thus, the silica synthesized without silane gas which can be determined as a silane-free procedure presents a clean and safe solution to manufactures. In this report, we used the radio frequency (rf = 13.56 MHz) plasma-enhanced chemical vapor deposition technique (PECVD) to form a silica layer at room temperature. The silica layer is formed in hydrogen-based plasma at room temperature and silane gas is not used in this process. The substrate temperature dominates the silica formation, but the distance between the substrate and electrode (DSTE) and the methane additive can enhance the formation of a silica layer on the Si wafer. This silane-free procedure, at room temperature, is not only safer and friendlier to the environment but is also useful in the fabrication of many types of sensors.

Zhou, Yingyu, e Hongling Chen. "Robust Super-Repellent Anisotropic Silica Films by Emulsion-Based Sol–Gel Growth". Nano 13, n. 01 (gennaio 2018): 1850005. http://dx.doi.org/10.1142/s1793292018500054.

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In this paper, anisotropic SiO2 with different morphologies were synthesized through an emulsion-based one-pot method by adding various silane coupling agents. Silane coupling agents affected the growth of silica nanostructures at the oil/water interfaces. Robust super-repellent film that showed great durability under different harsh conditions were obtained by bonding the self-assembled anisotropic silica nanostructures (ASN) film to substrate by the commercial acrylic adhesive. The film switched from superhydrophobic (157.1[Formula: see text] to superhydrophilic (0[Formula: see text] after being heat-treated at 500[Formula: see text]C. Further, silane treatment with addition of acid reduced the time of modification. Meanwhile, silane grafting density was improved and superhydrophobicity of calcinated ASN films was regenerated.

Na, Moon Kyong, Dong Pil Kang, Hoy Yul Park, Myeong Sang Ahn e In Hye Myung. "Properties of Nano-Hybrid Sol-Gel Materials Synthesized from Colloidal Silica-Silane Containing Epoxy Silane". Key Engineering Materials 336-338 (aprile 2007): 2278–81. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.2278.

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Three kinds of colloidal silica (CS)/silane sol solutions were synthesized in variation with parameters such as different acidity and reaction time. Sol solutions were prepared from HSA CS/ methyltrimethoxysilane (MTMS), LS CS/MTMS and LS CS/MTMS/γ -Glycidoxypropyltri methoxysilane (ES) solutions. In order to understand their physical and chemical properties, sol-gel coating films were fabricated on glass. Coating films on glass, obtained from LS/MTMS sol, had high contact angle, also, much enhanced flat surface in the case of LS/MTMS sol was observed in comparison with HSA/ MTMS sol. From all sol-gel solutions, seasoning effect of for enhancing properties of sol-gel coating layer on glass was observed while such sol-gel solutions were left for 7days. In initial stage of sol-gel reaction, all most of sol solutions used in this work seem to be unstable, formation of coating films was a little hazy and rough. However, improved coating films as observed in 4days later. LS/MTMS/ES sol solutions were synthesized with ES, adding to LS/MTMS sol. Contact angle of LS/MTMS/ES sol-gel coating films decreased, since ES played a role in forming hydrophilic hydroxyl sol. The elastic portion of coating films prepared from LS/MTMS/ES sol increased with addition of ES, but thermal stability decreased a little.

Mahdi, Billal, e Farid Rouabah. "Effect of Titanium Dioxide Nanoparticles on the Properties of Poly(Vinyl Alcohol)/Silica Hybrid Films Prepared by the Sol-Gel Method". Nano Hybrids and Composites 38 (3 febbraio 2023): 63–79. http://dx.doi.org/10.4028/p-381bv9.

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This work is focused on the preparation and characterization of poly (vinyl alcohol)/silica gel/Nano-TiO2, and the study of titanium dioxide (TiO2) nanoparticles (from 1 to 5%) on the properties of poly (vinyl alcohol) (PVA)/silica films. This new material was prepared by the sol-gel method using poly (vinyl alcohol) powder with Tetraethyl Orthosilicate (TEOS) as a precursor source of silica. TEOS was hydrolyzed and condensed in water and ethanol in the presence of hydrochloric acid (HCl) used as a catalyst. Fourier transform infrared (FT-IR), water absorption, water contact angle, ultraviolet-visible spectrometry (UV-VIS), and thermogravimetric analysis (TGA) were used to characterize the hybrid films obtained. The PVA/SiO2/Nano-TiO2 films were successfully synthesized. Owing to the FT-IR Analysis, the chemical bonds have clearly shown that the PVA backbone is linked to the (SiO2-TiO2) network. UV-VIS tests indicated that the hybrid films' UV shielding properties were drastically enhanced as a result of the addition of TiO2. According to the TGA tests, the hybrid films are more heat tolerant than neat PVA films. The water contact angle results revealed that TiO2 nanoparticles used as a doping compound possess an important influence on the hydrophilicity of PVA/SiO2 as thin films. The film's water resistance has also been enhanced.

Kurniasih, Yeti, Hasan Basri e Baiq Asma Nufida. "The Effect of Type and Concentration of Receiving Phase on Silver Separation Efficiency by Supported Liquid Membrane Technique". Jurnal Ilmiah Mandala Education 10, n. 1 (4 gennaio 2024): 53. http://dx.doi.org/10.58258/jime.v10i1.6504.

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The Effect of The Type and Concentration of The Receiving Phase on The Efficiency Of Silver Separation with Liquid Supported Membrane Techniques. The process of making negative x-ray films in a radiology laboratory produces liquid wastes containing various chemical compounds with the main content being Ag metal (in the form of Ag+ cations). This waste is categorized as a dangerous and toxic material. Therefore it is necessary to separate the Ag metal before it is discharged into the environment so as not to be harmful to life and the environment. One of the separation techniques that can be used is with supported fluid membrane technique (Supported Liquid Membrane, SLM). The supported liquid membrane has three important components: the feed phase containing the component to be separated, the membrane phase containing the carrier compound and the receiving phase containing the integral component. The three-phase composition determines the efficiency of the separation process. This study aims to identify the type and concentration of the receiving phase solution to improve silice metal separation efficiency by SLM technique. To obtain an efficient composition in the recipient phase was carried out by varying the type of acid received solution ie H3PO4, HNO3 and CH3COOH with respective concentrations of 0.01; 0.05; 0.10; 0.15; and 0.20 M. Measurement of metal ion concentration of Ag+ before and after transport was determined by Atomic Absorption Spectrophotometer (SSA) at wavelength 328,22 nm. Based on the result of research that type and concentration of acid solution in the receiving phase has an effected on separation efficiency. The optimum transport percentage has obtained on the used of H3PO4 receptor solution at a concentration of 0.1 M with a percentage of Transport Ag of 46.84%.

Più fonti

Tesi sul tema "Films de silice":

Basnig, Deomila. "Élaboration de films minces de silice pour des applications en chimie analytique". Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0102.

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Un film orienté à base de silice mésoporeuse sur une électrode FTO a été préparé par une approche d'auto-assemblage assistée par électrochimie (EASA). Un potentiel de -1,5 V a été appliqué à l'électrode FTO contenant un précurseur de silice préhydrolysée (par exemple, l'orthosilicate de tétraéthyle), en présence d'un modèle (par exemple, le bromure de cétrimonium) et d'un électrolyte. Cette approche permet de générer des nanocanaux de silice alignés verticalement avec des tailles de pores ajustables entre 2 et 3 nm, selon le modèle. Ce travail a montré le comportement voltammétrique et la sélectivité du film de silice mésoporeuse vis-à-vis de divers cations chargés positivement de nature, de taille et de charge différentes. Les résultats ont montré une accumulation et une sélectivité favorisant l'ion le moins chargé positivement : MB⁺ > PQ²⁺ > DQ²⁺ > Ru(bpy)₃²⁺ > Ru(NH₃)₆³⁺. L'augmentation des signaux voltamétriques par rapport à l'électrode FTO nue dépendait fortement du type de sonde. L'accumulation des différentes sondes redox est attribuée à l'orientation verticale du nanocanal qui favorise le transport rapide et la diffusion à la surface de l'électrode. Une caractérisation électrochimique plus poussée a montré une interaction entre le processus contrôlé par la surface et le processus contrôlé par la diffusion, où les espèces adsorbées sont plus importantes dans les milieux dilués. Les résultats ont montré que la modification de la longueur debye et du rayon électrocinétique du nanocanal de silice en raison de la force ionique ou du diamètre du nanocanal affecte également le transport et la détection électrochimique de l'analyte paraquat. Les films de silice mésoporeuse ayant des tailles de pores différentes, préparés en utilisant différents bromure d'alkylammonium comme modèle, donnent des sensibilités différentes, qui pourraient être dues à la différence de charge électrochimique de la surface de la silice, ainsi qu'à la distribution des ions dans le nanocanal. Enfin, une tentative de modification de la surface de la paroi de silice en utilisant de la zircone a également été faite pour étudier le transport des cations, ce qui pourrait ouvrir la voie à une meilleure stabilité du film mésoporeux
Oriented mesoporous silica-based film on FTO electrode was prepared via electrochemically-assisted self-assembly approach (EASA). A potential of -1.5V was applied to the FTO electrode containing a prehydrolyzed silica precursor, (e.g. tetraethyl orthosilicate), in the presence of a template (e.g. cetrimonium bromide) and electrolyte. This approach could generate vertically-aligned silica nanochannels with pore sizes adjustable between 2 and 3 nm, depending on the template. This work showed the voltammetric behavior and the selectivity of the mesoporous silica film towards various positively-charged cations of different nature, size, and charge. Results showed an accumulation and selectivity favoring the least positive charged ion: MB⁺ > PQ²⁺ > DQ²⁺ > Ru(bpy)₃²⁺ > Ru(NH₃)₆³⁺. The enhancement of the voltammetric signals relative to the bare FTO electrode was strongly dependent on the probe type. The accumulation of the different redox probe is attributed to the due to the vertical orientation of the nanochannel favoring fast transport and diffusion unto the electrode surface. Further electrochemical characterization showed an interplay of the suface-controlled and diffusion-controlled process, wherein adsorbed species is more prominent in diluted media. Results showed that changing the debye length and electrokinetic radius of the silica nanochannel due to the ionic strength or nanochannel diameter also affects the transport and electrochemical detection of the paraquat analyte. Mesoporous silica films having different pore size, prepared using different alkyl ammonium bromide as template, yield different sensitivities, which could be due to the difference in electrochemical charge of the silica surface, as well as the distribution of ions in the nanochannel. Finally, an attempt to modify the surface of silica wall using zirconia was also made to study the transport of cations, which could pave a way for an improved stability of the mesoporous film

Wora, Adeola Ganye Vergnat Michel Rinnert Hervé. "Propriétés de luminescence de films d'oxyde de silcium dopés à l'erbium". S. l. : S. n, 2007.

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CABOT, BENJAMIN. "Etudes pour l'elaboration par electrophorese de films anticorrosion a base de silice". Besançon, 1997. http://www.theses.fr/1997BESA2055.

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L'objectif de ce travail est de realiser des couches a base d'oxydes mineraux sur des pieces d'acier et d'acier zingue-chromate destinees a la protection contre la corrosion (basse et haute temperature). Pour cela nous utilisons une technique de depot par electrophorese, qui est basee sur la migration des particules, dans un champ electrique, vers l'une des electrodes. La presence de couches intermediaires sur l'acier necessite d'inverser tout d'abord la charge de surface des particules de silice. Pour cela nous adoptons trois systemes : silice-cation divalent, silice-polymere cationique, silice-oxyde mineral. L'utilisation de cations metalliques (comme le zinc) ne permet cependant pas d'inverser directement la charge des particules mais seulement de neutraliser la surface. Par contre l'adsorption de polymere cationique (polyvinylimidazole) et d'oxyde mineral (oxyde de cerium) est un moyen efficace pour produire des particules positives. L'etude de la reaction d'electrode lors du depot electrophoretique met en evidence que la formation d'une couche homogene sur la piece d'acier depend fortement de la capacite qu'ont les particules a neutraliser leur charge lorsqu'elles arrivent au voisinage de l'electrode. Cette etude met en evidence la difficulte d'elaborer un depot electrophoretique en milieu aqueux. La polarisation du substrat doit etre suffisante pour reduire electriquement la charge des particules, mais pas trop elevee pour eviter les reactions electrolytiques du solvant (degagement d'hydrogene et d'oxygene).

Sikolenko, Taisiia. "Films minces de silice mésoporeuse électrogénérée : contrôle de l’épaisseur et applications analytiques". Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0242.

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La modification d’électrodes par des films de silice mésoporeuse (FSM) ouvre des perspectives intéressantes dans le développement de capteurs électrochimiques. En particulier, la combinaison de la méthode électrochimique EASA (electrochemically-assisted self-assembly) permet d’obtenir des films fins et réguliers de silice mésoporeuse, de structure hexagonale et des pores perpendiculaire à la surface du support. Ces caractéristiques singulières contribuent à des transports de matière extrêmement rapides et indispensables aux applications type capteurs. La première partie du projet est centrée sur la réduction de l'épaisseur du FSM pour obtenir le plus fin tout en préservant sa structure hexagonale organisée et minimiser les effets négatifs du dépôt tout en ne gardant que ses bénéfices. Nous avons tout d’abord déterminé que, par la méthode de déposition EASA, l’épaisseur minimale d’un film homogène et sans défaut pouvant être atteinte dans nos conditions opératoires ([Si] = 100 mM, 32 mM CTAB) est de 80 ± 9 nm pour 10 s du potentiel -1.3V/Ag appliqué. Notre approche pour obtenir des couches plus fines que cela a consisté à dissoudre le FSM par voie humide, en utilisant le fluorure d’ammonium, NH4F, comme réactif «doux». La dissolution la plus contrôlée a été observée pour les FSMs dont le tensioactif est conservé dans la structure poreuse. La présence du CTAB favorise le transport et l’accumulation des ions fluorure dans le film accélérant ainsi la réaction (1.1 nm/min avec NH4F 0.05 M). L’épaisseur du FSM le plus fin obtenu dans ces conditions est de 28 ± 9 nm. Lorsque le traitement est mené sur des FSMs pour lesquels le tensioactif a été extrait par voie humide ou par calcination, l’épaisseur la plus petite atteinte sans créer de défaut dans le film est seulement de 57 ± 11 nm. Dans la deuxième partie de l'étude, les FSMs ont été fonctionnalisés par un complexe organométallique de ruthénium(II) dans le but d’essayer de développer une plateforme d'électrochimiluminescence pour la détection du glyphosate. L’originalité de l’approche est le choix d’immobiliser de manière covalente le complexe ruthénium(II) tris(bipyridine), Ru(bpy)₃²⁺, au sein du FSM. L’approche par chimie «click» a été privilégiée et réalisée sur un FSM modifiée par des groupements azoture préparé par co-condensation. Les premiers résultats électrochimiques obtenus en présence de glyphosate ont montré que la présence du pesticide conduit à une modification du signal électrochimique quelle que soit la nature de l’électrode utilisée. La détection de l’herbicide est ainsi possible. On remarque cependant que la nature du signal enregistré avec une électrode modifiée par un FSM où le complexe organométallique a été préalablement greffé est différent de celui obtenu avec les autres électrodes et pas encore totalement expliqué
The combination of rich surface chemistry of silica and ordered perpendicularly-standing hexagonal mesostructure of films generated by EASA makes this material a perfect choice for use as the electrode coatings. In this light, improvement of film design is a constant challenge in order to benefit from porous layer and to increase the efficiency of electrochemical sensors. The first part of project was centred around the optimisation of the film thickness towards the thinnest with preservation of the beneficial hexagonal structure. The mesoporous silica film (MSF) thickness is a parameter that can affect the mass transport through the silica coating to the electrode specifically because of the reactivity of surface silanol groups. Thinning of the MSF can facilitate the diffusion of species, while keeping the presence of the beneficial silica layer can increase the electrochemical response, hence, the sensitivity of analysis. Two approaches were used in order to decrease thickness. The first was a study of the effect of the deposition time during the modification of the electrode (EASA process). The second one was the wet etching of film after its deposition. The thinnest uniform MSFs, which can be generated on indium tin oxide (ITO) surface, require minimum 10 seconds deposition with an applied potential equal to -1.3 V and a 100 mM silane-containing sol. This gave rise to 80 ± 9 nm coating. Post-synthesis etching with the soft fluoride solution of ammonium fluoride, NH4F, allowed to control the decrease of the MSF thickness. By keeping the surfactant inside the silica pores, template agent for the synthesis, the kinetic of the etching reaction was faster, but with a more homogeneous dissolution. It was possible to obtain the thinnest ordered MSF in comparison with an etching procedure conducted on MSF after the extraction of the template. The profilometry determined thickness of well-structured film with vertical pore orientation was respectively of 28 ± 9 nm for the templated silica films and 57 ± 11 nm for films without surfactant inside their pores. In the second part of the study, MSFs were applied to modify ITO electrodes for the development of electrochemiluminescence platform for detection of amine-containing herbicide glyphosate using co-reactant system with Ru(bpy)₃²⁺. Comparison between physical and chemical immobilisation of the organometallic agent was studied. Covalent functionalisation was achievable due to introduction of azide functions on co-condensation step with their further coupling with propargyl-functionalised derivative of Ru(bpy)₃²⁺ complex by Huisgen 1,3-cycloaddition reaction. The effect of the herbicide addition was investigated using electrodes with immobilised by two approaches Ru(bpy)₃²⁺ complex as well as in solution of Ru(bpy)₃²⁺, operating bare ITO electrode and ITO electrode covered with unmodified MSF. The evolution of electrochemical signal was used to conclude on the possibility to detect glyphosate

Motos, Blanca. "Silices fonctionnalisées contenant des espèces ioniques pour la catalyse hétérogène". Thesis, Montpellier, Ecole nationale supérieure de chimie, 2011. http://www.theses.fr/2011ENCM0015.

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La catalyse hétérogène est en plein développement pour des raisons économiques, de santé et de protection environnementale. Les travaux de cette thèse s'intéressent à la préparation des silices fonctionnalisées par des sous-structures ioniques pour leur application en catalyse hétérogène. D'abord, des matériaux mésoporeux fonctionnalisés par des entités di-aryl imidazoliums ont été préparés par des réactions de post-greffage. En plus, films de type PMO contenant des entités di-aryl imidazoliums ont été synthétisés en présence d'un surfactant anionique. Ensuite, complexes carbéniques N-hétérocycliques du cuivre et du palladium supportés ont été préparés et appliqués en tant que catalyseurs organométalliques dans des réactions A3 (Cu-NHC) et de couplage de Suzuki (Pd-NHC). Les silices fonctionnalisées avec des entités imidazoliums ont également été utilisées en tant qu'organocatalyseurs des réactions de Henry et dans de cycloaddition du dioxyde de carbone aux époxydes. Des matériaux de type ‘PMO' contenant des entités amines/ammoniums ainsi que des sous-structures zwitterioniques ont été utilisés en réactions organocatalysées de Henry et Biginelli
Heterogenous catalysis is an area in continuous development due to economical, health and environmental issues. This thesis deals with the preparation of i-silica materials for the posterior application in heterogeneous catalysis. First, di-aryl imidazolium containing silica materials were synthesized by post-grafting reactions on mesoporous SBA-15. Moreover, di-alkyl imidazolium containing PMO films were prepared in presence of an anionic surfactant. Then, supported copper and palladium N-heterocyclic carbenes were synthesized from di-aryl imidazolium silica and applied to A3 reactions (Cu-NHC) and Suzuki cross-coupling reactions (Pd-NHC). Imidazolium functionalized silicas were also utilized as heterogeneous organocatalysts in Henry reactions and in reactions of cycloaddition of carbon dioxide to epoxides. Finally, PMO type materials containing amine/ammonium and zwitterionic substructures were applied to Henry and Biginelli organocatalysed reactions, respectively

JIANG, NAN. "Etude de films minces de silice deposes a basse temperature par pecvd rcer". Paris 11, 1993. http://www.theses.fr/1993PA112340.

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Les films minces dielectriques deposes a basse temperature presentent actuellement et presenteront dans le futur de multiples applications dans le domaine de l'industrie micro-electronique: les transistors tft (thin film transistor) pour les ecrans plats a matrice active, les dispositifs sur semi-conducteurs iii. V (gaas, inp, ingaas,. . . ) pour les circuits integres. Ces differentes applications necessitent, pour leur realisation, des dielectriques deposes a basse temperature. Nous presentons dans ce memoire, l'etude de l'optimisation de films minces de silice deposes, a partir d'un nouveau type de reacteur micro-onde: le reacteur a resonance cyclotronique electronique repartie (rcer). Ces films rcer, obtenus (sans chauffer intentionnellement l'echantillon), ont ete utilises avec succes pour realiser la premiere etape de fabrication des ecrans plats, c'est-a-dire plus precisement pour elaborer des transistors tft sur substrat soi (silicon ou insulator). Leurs proprietes physico-chimiques et electriques sont tres proches de celles de la silice thermique obtenue a haute temperature (1000c) jusqu'a present, et a notre connaissance, la silice rcer semble etre l'une des meilleures silices deposees a basse temperature. Nous avons etudie l'influence de la nature du gaz oxydant (o#2, n#2o), de la composition de la phase gazeuse (o#2/sih#4, n#2o/sih#4) et de la polarisation radiofrequence du substrat sur les proprietes de nos films. La maitrise du depot de silice passe par la mise en uvre de nombreux moyens de caracterisation tels que: l'ellipsometrie, la microanalyse nucleaire, l'analyse par detection des atomes de recul, la dissolution chimique, la spectroscopie d'absorption infrarouge, la microscopie a force atomique, la microscopie electronique a transmission et enfin des caracterisations electriques. Nous avons egalement etudie les proprietes du plasma rcer. Les variations du courant ionique enregistrees en fonction de la nature des gaz, de la pression dans l'enceinte et de la puissance micro-onde, nous ont permis de mieux comprendre le comportement de ce nouveau plasma

Cagnol, Florence. "Films minces mesostructures minéraux ou hybrides à base de silice : élaboration, caractérisation, mécanismes". Paris 6, 2004. http://www.theses.fr/2004PA066443.

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Sibottier, Emilie Walcarius Alain. "Génération électro-assistée de films à base de silice fonctionnalisation, mésostructuration et applications analytiques /". S. l. : S. n, 2007. http://www.scd.uhp-nancy.fr/docnum/SCD_T_2007_0101_SIBOTTIER.pdf.

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Dourdain, Sandrine. "Caractérisation structurale, poreuse et mécanique de films minces de silice mésoporeuse.Influence de la fonctionnalisation". Phd thesis, Université du Maine, 2006. http://tel.archives-ouvertes.fr/tel-00201895.

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Abstract (sommario):

Ce travail de thèse a porté sur la synthèse et la caractérisation de films minces de silice mésoporeuse. La synthèse de ces matériaux est basée sur l'auto-organisation de tensioactifs qui permettent de structurer à l'échelle nanométrique un squelette, constitué ici d'un gel de silice.
Les paramètres pertinents influençant la structuration des films minces ont été appréhendés. En particulier, des études in situ par réflectivité des rayons X et par Diffusion en incidence rasante des rayons X (Grazing Incidence Small Angle X-ray Scattering, GISAXS), ont permis de mettre en évidence le rôle prédominant de l'humidité relative. Des protocoles d'extraction par rinçage à l'éthanol ont été établis pour dégager efficacement les structures mésoporeuses sans les écraser.
Une méthode d'analyse de la porosité des films minces a ensuite été développée. Cette méthode est basée sur l'analyse quantitative des courbes de réflectivité par la méthode matricielle. Complémentée par l'analyse des clichés GISAXS, elle nous a permis de déterminer sur couche mince non seulement la porosité, la taille des pores et des murs mais aussi la surface spécifique et la distorsion des pores.
Les pores de ces films mésoporeux ont une dimension idéale pour y parfaire l'étude de la condensation capillaire de l'eau. Quand l'eau pénètre dans les pores, le contraste de densité électronique décroît fortement. Ainsi, les techniques de diffusion des rayons X (réflectivité et GISAXS) permettent de suivre les isothermes de condensation et de désorption de l'eau dans les pores. La distribution de taille des pores peut alors être obtenue. Les isothermes d'adsorption d'eau ont permis également d'estimer la porosité, mais aussi d'appréhender par le biais de l'équation de Laplace, les propriétés mécaniques des films en accédant à leur module d'Young.
Finalement nous avons conclu cette thèse par l'étude de la fonctionnalisation des films par divers groupements fonctionnels localisés à la surface des mésopores, dans l'optique de modifier leur hydrophilicité ou leur réactivité chimique.

Sibottier, Emilie. "Génération électro-assistée de films à base de silice : fonctionnalisation, mésostructuration et applications analytiques". Thesis, Nancy 1, 2007. http://www.theses.fr/2007NAN10101/document.

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L’étude menée concerne divers aspects d’une nouvelle voie de synthèse sol-gel : la génération électro-assistée de films à base de silice fonctionnalisée et/ou mésostructurée, ainsi que leurs applications en électrochimie analytique. Des films à base de silice fonctionnalisée par des groupements amine ou thiol ont été déposés sur électrode d’or par catalyse électrochimiquement assistée de la polycondensation. La formation d’une monocouche auto-assemblée partielle de mercaptopropyltriméthoxysilane permet une très bonne adhésion du film silicaté sur la surface d’or. Le processus d’électro-dépôt est caractérisé par deux étapes successives de vitesse différente. A une étape de dépôt lent et régulier succède une croissance bien plus rapide du film. L’utilisation des électrodes modifiées a été envisagée en tant que capteur de Cu2+. En introduisant un tensioactif dans le sol de synthèse, il est possible d’électrogénérer des films à base de silice mésoporeuse de structure hexagonale avec les pores orientés perpendiculairement par rapport au substrat (difficile à obtenir par d’autres méthodes). Il semblerait que l’électrochimie permette à la fois un contrôle de la structure du tensioactif à la surface de l’électrode et la croissance simultanée du film sol-gel. Cette méthode d’électrogénération permet aussi d’obtenir des films fins homogènes sur des surfaces non planes ou présentant des hétérogénéités de conductivité. Enfin, une approche préliminaire a été proposée visant à appliquer le processus d’électrogénération, couplé à la technique de microscopie électrochimique à balayage, pour déposer localement des films à base de silice sous forme de plots de taille micrométrique sur or
The study deals with various aspects of a novel method of sol-gel synthesis : the electro-assisted generation of functionalized and/or mesostructured silica thin films, and their applications in analytical electrochemistry. Sol-gel-derived silica films functionnalized with amine or thiol groups have been electrogenerated on gold electrodes. The formation of a partial self-assembled monolayer of mercaptopropyltrimethoxysilane (MPTMS) on gold led to a silica film adhering well to the electrode surface owing to the MPTMS acting as a « molecular glue ». The whole process was characterized by two successive distinct rates, starting by a slow deposition stage leading to thin deposits, which was followed by a much faster film growing in the form of macroporous coatings. The use of these modified electrodes was considered as a voltammetric sensor for copper(II). By adding a surfactant in the synthesis medium, it’s possible to electrogenerate mesostructured silica films with hexagonal structure with pore channels oriented perpendiculary to the substrate (which is difficult to get by other methods). The electrochemically-induced-self-assembly of surfactant-templated silica thin films can be applied to various conducting supports. The broad interest of the novel method was demonstrated by its ability to produce homogeneous deposits of silica on non-planar surfaces or heterogeneous substrates, what is difficult by the traditional techniques of film deposition. Finally, a preliminary approach has been proposed in order to apply the electrodeposition process coupled with a scanning electrochemical microscope in order to get localized sol-gel deposits at the micrometric size level on gold

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Libri sul tema "Films de silice":

Symposium on Silicon Nitride, Silicon Dioxide Thin Insulating Films, and Emerging Dielectrics (9th 2007 Chicago, Ill.). Silicon nitride, silicon dioxide, and emerging dielectrics 9. A cura di Sah R. E, Electrochemical Society. Dielectric Science and Technology Division. e Electrochemical Society Meeting. Pennington, N.J: Electrochemical Society, 2007.

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Symposium on Silicon Nitride and Silicon Dioxide Thin Insulating Films (8th 2005 Québec, Québec). Silicon nitride, silicon dioxide thin insulating films, and other emerging diele[c]trics VIII: Proceedings of the international symposium. A cura di Sah R. E, Electrochemical Society. Dielectric Science and Technology Division., Electrochemical Society Electronics Division e Electrochemical Society Meeting. Pennington, N.J: Electrochemical Society, 2005.

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B, Bergmann Ralf, e Research Signpost (Trivandrum India), a cura di. Growth, characterization, and electronic applications of si-based thin films. Trivandrum: Research Signpost, 2002.

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Symposium on Silicon Nitride and Silicon Dioxide Thin Insulating Films (5th 1999 Seattle, Wash.). Silicon nitride and silicon dioxide thin insulating films: Proceedings of the fifth international symposium. Pennington, NJ (10 S. Main St., Pennington 08534-2696: Electrochemical Society), 1999.

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Symposium on Silicon Nitride and Silicon Dioxide Thin Insulating Films (7th 2003 Paris, France). Silicon nitride and silicon dioxide thin insulating films VII: Proceedings of the international symposium. A cura di Sah R. E, Electrochemical Society. Dielectric Science and Technology Division., Electrochemical Society Electronics Division e Electrochemical Society Meeting. Pennington, NJ: Electrochemical Society, 2003.

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Innocenzi, Plinio. Mesoporous Ordered Silica Films. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-89536-5.

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P, Jennings J., e Hefter G. T, a cura di. Amorphous silicon thin films and devices: Results of research carried out as MERIWA Project No. E161 in the School of Mathematical and Physical Sciences, Murdoch University. East Perth, WA: Minerals and Energy Research Institute of Western Australia, 1993.

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Narayanan, V., e Martin M. Frank. Thin films on silicon. Singapore: World Scientific Publishing Co. Pte. Ltd, 2016.

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Capitoli di libri sul tema "Films de silice":

Eisele, I., J. Schulze e E. Kasper. "Films by Molecular-Beam Epitaxy". In Silicon, 95–122. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-662-09897-4_6.

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Gonçalves, M. Clara, e George S. Attard. "Nanostructured Mesoporous Silica Films". In Nanostructured Materials and Coatings for Biomedical and Sensor Applications, 159–68. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-010-0157-1_16.

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Krimmel, Eberhard F., Rudolf Hezel, Uwe Nohl e Rainer Bohrer. "Insulating Silicon Nitride Films". In Si Silicon, 72–76. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-662-09901-8_4.

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Slaoui, A., e P. Siffert. "Polycrystalline Silicon Films for Electronic Devices". In Silicon, 49–72. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-662-09897-4_4.

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Ali, Atif Mossad, e Takao Inokuma. "Nanocrystalline silicon thin films". In Silicon Nanomaterials Sourcebook, 97–106. Boca Raton, FL: CRC Press, Taylor & Francis Group, [2017] | Series: Series in materials science and engineering: CRC Press, 2017. http://dx.doi.org/10.4324/9781315153544-5.

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Abedrabbo, S., B. Lahlouh, S. Shet, A. T. Fiory e N. M. Ravindra. "Spin-Coated Erbium-Doped Silica Sol-Gel Films on Silicon". In Supplemental Proceedings, 677–84. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2012. http://dx.doi.org/10.1002/9781118356074.ch86.

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Shaikhutdinov, Shamil. "Water Adsorption on Silica Films". In Introduction to Ultrathin Silica Films Silicatene and Others, 271–91. New York: Jenny Stanford Publishing, 2022. http://dx.doi.org/10.1201/9781003088622-8.

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Shaikhutdinov, Shamil. "Ultrathin Silica Films on Metals". In Introduction to Ultrathin Silica Films Silicatene and Others, 107–65. New York: Jenny Stanford Publishing, 2022. http://dx.doi.org/10.1201/9781003088622-4.

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Morita, Mizuho. "Native Oxide Films and Chemical Oxide Films". In Ultraclean Surface Processing of Silicon Wafers, 543–58. Berlin, Heidelberg: Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/978-3-662-03535-1_42.

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Krimmel, Eberhard F., Rudolf Hezel, Uwe Nohl e Rainer Bohrer. "Specific Applications of Silicon Nitride Films". In Si Silicon, 316–20. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-662-09901-8_31.

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Atti di convegni sul tema "Films de silice":

Poulsen, Christian V., Mikael Svalgaard e Ove Poulsen. "Photosensitivity in germania-doped silica films". In The European Conference on Lasers and Electro-Optics. Washington, D.C.: Optica Publishing Group, 1994. http://dx.doi.org/10.1364/cleo_europe.1994.cmm5.

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Abstract (sommario):

Integrated optics is believed to be the key technology for future integrated optical systems. One standard method for processing planar waveguides is a combination of plasma enhanced chemical vapor deposition (PECVD) for growing glass layers and photolithography/reactive ion etch (RIE) for creating the waveguides2 (Fig. la). We present an investigation of the photosensitivity of germania-doped silica films. The results may lead to an alternate method for creating the guiding structure in planar waveguides that requires much fewer process steps. Instead of using a combination of photolithography and RIE for defining the guiding core, the index change due to photosensitivity of germanium-doped silica may be utilized (Fig. 1b). To investigate the photosensitivity, germanium-doped silica films were grown on a 4" silicon wafer in a PECVD chamber. These films were fabricated at a temperature of 300°C, a base pressure of 700 mTorr, and gas flows of 17 seem silane, 1600 sccm nitrousdioxide and up to 8 sccm germane followed by annealing at 800°C in a nitrogen atmosphere for two hours.

Coquil, Thomas, Neal Hutchinson, Laurent Pilon, Erik Richman e Sarah Tolbert. "Thermal Conductivity of Cubic and Hexagonal Mesoporous Silica Thin Films". In ASME 2009 Heat Transfer Summer Conference collocated with the InterPACK09 and 3rd Energy Sustainability Conferences. ASMEDC, 2009. http://dx.doi.org/10.1115/ht2009-88256.

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This paper reports the cross-plane thermal conductivity of highly ordered cubic and hexagonal templated mesoporous amorphous silica thin films synthesized by evaporation-induced self-assembly process. Cubic and hexagonal films featured spherical and cylindrical pores and average porosity of 25% and 45%, respectively. The pore diameter ranged from 3 to 18 nm and film thickness from 80 to 540 nm while the average wall thickness varied from 3 to 12 nm. The thermal conductivity was measured at room temperature using the 3ω method. The experimental setup and the associated analysis were validated by comparing the thermal conductivity measurements with data reported in the literature for the silicon substrate and for high quality thermal oxide thin films with thickness ranging from 100 to 500 nm. The cross-plane thermal conductivity of the synthesized mesoporous silica thin films does not show strong dependence on pore size, wall thickness, or film thickness. This is due to the fact that heat is mainly carried by very localized non propagating vibrational modes. The average thermal conductivity for the cubic mesoporous silica films was 0.30 ± 0.02 W/mK, while it was 0.20 ± 0.01 W/mK for the hexagonal films. This corresponds to a reduction of 79% and 86% from bulk fused silica at room temperature.

Fang, Jin, Laurent Pilon, Chris B. Kang e Sarah H. Tolbert. "Thermal Conductivity of Ordered Mesoporous Silicon Thin Films Made From Magnesium Reduction of Polymer Templated Silica". In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-64784.

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This paper reports the cross-plane thermal conductivity of ordered polycrystalline mesoporous silicon thin films between 30 and 320 K. The films were produced by a combination of evaporation induced self-assembly (EISA) of mesoporous silica followed by magnesium reduction. The periodic ordering of pores in mesoporous silicon was characterized by a combination of 1D X-ray diffraction, 2D small angle X-ray scattering, and direct SEM imaging. The average crystallite size, porosity, and film thickness were about 13–18 nm, 25–35%, and 140–260 nm, respectively. The pores were arranged in a face-centered cubic lattice. Finally, the cross-plane thermal conductivity of the meso-porous silicon thin films was measured using the 3ω method. The measured thermal conductivity was about 3 to 5 orders of magnitude smaller than that of the bulk dense crystalline silicon for the temperature range considered. The effects of temperature and film thickness on the thermal conductivity were investigated.

Hur, Soojung C., Laurent Pilon, Adam Christensen e Samuel Graham. "Thermal Conductivity of Cubic Mesoporous Silica Thin Films". In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-43016.

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This paper reports, for the first time, the cross-plane thermal conductivity of highly ordered cubic mesoporous silica thin films with porosity of 31% and thickness ranging between 200 and 500 nm. The mesoporous thin films are synthesized based on evaporation induced self-assembly process. The pores are spherical with average inter-pore spacing and pore diameter equal to 5.95 nm and 5 nm, respectively. The thermal conductivity is measured at room temperature using the 3ω method. The experimental setup and the associated analysis are validated by comparing the thermal conductivity measurements for the silicon substrate and for high quality thermal oxide thin films with data reported in the literature. The cross-plane thermal conductivity of the synthesized mesoporous silica thin films does not strongly depend on film thickness due to the reduction in phonon mean free path caused by the presence of nanopores. The average thermal conductivity is 0.61 ± 0.011 W/mK, which is 56% lower than that of bulk fused silica at room temperature.

Dahle, Sebastian, Lienhard Wegewitz, Fei Qi, Alfred P. Weber e Wolfgang Maus-Friedrichs. "Silicon dioxide coating of titanium dioxide nano particles from dielectric barrier discharge in a gaseous mixture of silan and nitrogen". In 13th International Conference on Plasma Surface Engineering September 10 - 14, 2012, in Garmisch-Partenkirchen, Germany. Linköping University Electronic Press, 2013. http://dx.doi.org/10.3384/wcc2.116-117.

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Titanium dioxide nanoparticles are used commonly in various applications due to their high catalytic activity. Many of these applications require subsequent treatments after the deposition of the TiO2 particles. Some of these include thermal processing at high temperatures, e.g. roof tiles. For all of these applications, the crystal structures as well as the microscopic properties are essential. Thus, sintering severely affects the catalytic activity in most of the cases. During thermal processing, the nanoparticles transform from the catalytical highly active anatas structure to the substantially less active rutil structure. This structural change has been found to be significantly retarded when coating the TiO2 nanoparticles with a closed film of SiO2. During the thermal treatment, these films break open, revealing the underlying TiO2 [i]. Thus, the film thickness has to be appropriate for the designated treatment subsequent to the nanoparticle deposition. In this study, we present an approach of SiO2 film deposition making use of silane gas. Pure silane gas is highly demanding on safety standards and technical installations, since it acts self-igniting and highly explosive when getting in contact with air or any oxygen containing gas. Thus, diluted process gases are used for most technical implementations, which contain just about 3% silane in 97% helium, neon, argon, hydrogen or nitrogen. While noble gases and hydrogen are used as dilution for a wide range of applications, the process gas consisting of nitrogen and silane is only implemented for silicon nitride deposition. Nevertheless, this gas should be the most suitable for many applications regarding economics and handling. Closed films produced by dielectric barrier discharges in such mixtures of gases consist of mainly non-stoichiometric silicon nitride, while the other diluted process gases produce metallic silicon films. The deposition of silicon dioxide films is rather complicated, since the silane reacts instantaneously with every oxygen-rich gas. Thus, both gases must not get in contact until they have arrived in front the surface that is to be coated. Most of the existing work found in the literature focuses on the implementation of this condition, to merge the silane and the oxygen right at the surface being coated. Taking a quite different approach, we divided the film deposition into two steps: In the first step, a silicon nitride film was deposited from the process gas with the silane diluted in nitrogen employing a dielectric barrier discharge plasma. As a second step, the silicon nitride film has been tried to convert into silicon dioxide by means of a second plasma discharge using either oxygen for a process gas or even environmental air. All studies have been carried out in an ultra high vacuum apparatus, while the plasma treatments have been carried out up to atmospheric pressure. During the investigations we employed Metastable Induced Electron Spectroscopy (MIES), Ultraviolet Photoelectron Spectroscopy (UPS) and X-ray Photoelectron Spectroscopy (XPS), as well as Atomic Force Microscopy (AFM). The microscopic measurements showed the deposited film to enclose the particles in a Frank van der Merwe – type growth mode. Film thicknesses determined by increased particle diameters in AFM were in good accordance to calculated film thicknesses from XPS peak intensity attenuation. Spectroscopic results show a formation of a silicon nitride film with substoichiometric nitrogen content, though free of oxynitrides. Surface impurities and adsorbates from the ex-situ preparation procedure were strongly removed and seemed to notably increase the growth rate. The second step gained a transformation of the film up to 98% silicon dioxide according to XPS. Remaining carbon impurities from the initially uncleaned surface were removed by both of the oxidizing plasmas. The transformation was found to be even more effective for the air plasma treatment than for the oxygen plasma treatment at a comparable oxygen partial pressure.

Cao, Zhiqiang, Tong-Yi Zhang e Xin Zhang. "A Nanoindentation-Based Microbridge Testing Method for Mechanical Characterization of Thin Films for MEMS Applications". In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-80288.

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Plasma-enhanced chemical vapor deposited (PECVD) silane-based oxides (SiOx) have been widely used in both microelectronics and MEMS (MicroElectroMechanical Systems) to form electrical and/or mechanical components. In this paper, a novel nanoindentation-based microbridge testing method is developed to measure both the residual stresses and Young’s modulus of PECVD SiOx films on silicon wafers. Theoretically, we considered both the substrate deformation and residual stress in the thin film and derived a closed formula of deflection versus load. The formula fitted the experimental curves almost perfectly, from which the residual stresses and Young’s modulus of the film were determined. Experimentally, freestanding microbridges made of PECVD SiOx films were fabricated using the silicon undercut bulk micromachining technique. The results showed that the as-deposited PECVD SiOx films had a residual stress of −155±17 MPa and a Young’s modulus of 74.8±3.3 GPa.

Allen, Thomas H. "Optical materials deposited using ion beam sputtering". In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1985. http://dx.doi.org/10.1364/oam.1985.fl4.

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Selected optical materials were deposited using combined ion beam sputter and ion-assisted deposition techniques. The influence of ion energy and current density on the properties of a growing film is discussed. Measured properties include optical constants, mechanical properties, microstructure, and stoichiometry. Optical materials include zirconia, titania, silica, aluminum nitride, and silicon nitride. Recent roughness measurements on ion sputter deposited over coated aluminum films are discussed.

Kobavashi, Junva, Tohru Maruno, Yasuhiro Hida, Tohru Matsuura e Shigekuni Sasaki. "Thermooptic switches using fluorinated polyimide waveguides". In Organic Thin Films for Photonic Applications. Washington, D.C.: Optica Publishing Group, 1997. http://dx.doi.org/10.1364/otfa.1997.fa.4.

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Abstract (sommario):

Thermooptic (TO) switches using polymer optical waveguides have attracted much attention because the TO effect of polymers is ten times that of silica. Therefore, using polymers instead of silica [1-2] significantly reduces the required switching power. Moreover, fabricating polymer optical waveguides is easier than fabricating silica-based ones, so large optical devices can be made more easily.

Yang, Huan, Ben Q. Li e Changhong Liu. "Enhanced Light Absorption in Thin Crystalline Silicon Solar Cells With Silica Nanoparticles". In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-52492.

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In this paper, numerical simulations are performed to investigate the effects of different configurations of dielectric SiO2 particles on the improvement of light absorption in 2-μm single crystal silicon photovoltaic solar cells. The numerical model is developed on the basis of the FDTD solution of the transient Maxwell equations and checked with analytical solutions for simple configurations and against experimental measurements of light absorption in bare Si films. The numerical model is also checked for mesh sensitivity such that the computed data are approximately mesh-insensitive. Computed results are analyzed and the short circuit current of the Si films is used as a measure of the efficiency for light trapping in Si films. Results show that with SiO2 nanoparticles closely packed atop the Si film, good improvement in light absorption efficiency is achieved if the particle is 700 nm in diameter. This is considered to be attributed to the anti-reflection effect of the particle layer and the whispering gallery mode of SiO2 particles excited by the incident light. If the closely arranged SiO2 nanoparticles are embedded half-way into a Si film through its top surface, the light absorption is enhanced by ∼120%, approaching to the Yablonovitch limit. The structured surface of the Si film can almost realize 100% anti-reflection of incident, because the use of the half embedded SiO2 particles in the top layer of the Si film creates a graded transition of the effective refractive index along the direction of incident; and as a result almost all the light with the wavelength below or near 500nm are absorbed due to the higher imaginary part of the refractive index. The improvement in light absorption with the wavelength greater than 500nm comes, however, from the resonance behavior of the SiO2 nanoparticles. Experiments are now planned and measurements of light absorption will be conducted with a photospectrometer to validate the above calculations.

Seo, Kang, Liqun Wang, Kyeongwoo Nam, Carl Bonner e Edward Gillman. "Morphology of Organic Thin Films on Silicon Substrate". In Organic Thin Films. Washington, D.C.: OSA, 2002. http://dx.doi.org/10.1364/otf.2001.otud7.

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Rapporti di organizzazioni sul tema "Films de silice":

Silcox, J., e E. J. Kirkland. Uhv-stem studies on nucleation and growth of thin metal silicide films on silicon. Office of Scientific and Technical Information (OSTI), gennaio 1992. http://dx.doi.org/10.2172/6207328.

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Kalnitsky, A., S. P. Tay, J. P. Ellul, J. W. Andrews, E. A. Irene e S. Chongsawagvirod. Measurements and Modelling of Thin Silicon Dioxide Films on Silicon. Fort Belvoir, VA: Defense Technical Information Center, maggio 1989. http://dx.doi.org/10.21236/ada207853.

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Mecholsky, Jr, Tsai J. J., Drawl Y. L. e W. R. Fracture Studies of Diamond Films on Silicon. Fort Belvoir, VA: Defense Technical Information Center, agosto 1991. http://dx.doi.org/10.21236/ada240978.

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Filip, Grażyna. SEMANTIC OF QUIET AND SILENCE BASED ON POLISH HUMAN SCIENCE. Ivan Franko National University of Lviv, marzo 2021. http://dx.doi.org/10.30970/vjo.2021.50.11103.

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Abstract (sommario):

The article is an introduction to an individual research subject called The Communicational Potential of Silence, planned – and partially already realised since 2020 – as a cycle of publications based on diversified example material. In print are already two texts: G. Filip, The Communicational Potential of Silence. Film Reviews (University of Rzeszów Publishing House) and G. Filip, The Communicational Potential of Silence. Automotive Brand Press Maria Curie-Skłodowska University of Lublin Publishing House). The presented here English-language article serves for popularization Poland-wide and local (University of Rzeszów) research in the field communications.

Martin U. Pralle e James E. Carey. Black Silicon Enhanced Thin Film Silicon Photovoltaic Devices. Office of Scientific and Technical Information (OSTI), luglio 2010. http://dx.doi.org/10.2172/984305.

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Smith, W. L., T. A. Michalske e R. R. Rye. The deposition of boron nitride and carbon films on silica glass fibers. Office of Scientific and Technical Information (OSTI), novembre 1993. http://dx.doi.org/10.2172/10110580.

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Irene, Eugene A. Silicon Oxidation Studies on Thin Film Silicon Oxidation Formation. Fort Belvoir, VA: Defense Technical Information Center, marzo 1989. http://dx.doi.org/10.21236/ada206835.

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Berman, G. P., G. D. Doolen, R. Mainieri, D. K. Campbell e V. A. Luchnikov. Molecular dynamics simulations of grain boundaries in thin nanocrystalline silicon films. Office of Scientific and Technical Information (OSTI), ottobre 1997. http://dx.doi.org/10.2172/292865.

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Gallagher, A., D. Doughty e J. Doyle. Diagnostics of glow discharges used to produce hydrogenated amorphous silicon films. Office of Scientific and Technical Information (OSTI), maggio 1990. http://dx.doi.org/10.2172/6910198.

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Keyes, Brian. National solar technology roadmap: Film-silicon PV. Office of Scientific and Technical Information (OSTI), giugno 2007. http://dx.doi.org/10.2172/1217298.

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