Dissertations / Theses on the topic 'Anodic Aluminium Oxide (AAO)'
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He, Xueying. "Characterization of Porous Anodic Aluminum Oxide Film by Combined Scattering Techniques." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1383645061.
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Romanovicz, Vanessa 1983, Deyse Elisabeth Ortiz Suman 1958 Carpenter, and Universidade Regional de Blumenau Programa de Pós-Graduação em Química. "Síntese de nanotubos de carbono utilizando caldo de cana como precursor e templates AAO (Anodic Aluminum Oxide) /." reponame:Biblioteca Digital de Teses e Dissertações FURB, 2011. http://www.bc.furb.br/docs/DS/2011/357584_1_1.pdf.
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Rafati, A. A., M. Najafi, and A. Zare. "Effect of Electrodeposition Frequency on Magnetic Properties of (Co0.97Al0.03)0.7Fe0.3 Nanowires." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35345.
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The magnetic properties of (Co0.97Al0.03)0.7Fe0.3 nanowires electrodeposited at different frequency of 50-
1000 Hz were studied. This nanowires were prepared by alternative current electrodeposition using porous
anodic aluminum oxide as template. The results show that coercivity of samples slightly increased with increasing
the frequency. Comparing the M–H hysteresis loops in different frequency shows that saturation
magnetization (Ms) per unit area decreases with increasing the frequency. Magnetic properties were also
investigated after annealing at 575 C. After annealing, a clear increase in coercivity was observed.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35345
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Chintakula, Goutam. "SCHOTTKY DIODES ON COPPER PHTHALOCYANINE NANOWIRE ARRAYS EMBEDDED IN POROUS ALUMINA TEMPLATES." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_theses/556.
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Vertically aligned nanowire arrays of copper phthalocyanine (CuPc) and CuPc-Al Schottky diodes, of controllable diameter and length were fabricated by cathodic electrodeposition of CuPc into anodized alumina (AAO) templates, followed by annealing at 300 ºC in Argon. AAO over Aluminum tape and that over ITO-glass were both used as starting templates for the device fabrication. Depending on the dimensions of the starting AAO template, diameters of CuPc nanowires ranged from 30 nm to 40 nm and the lengths ranged from 500 nm to 1 μm. The temperature dependence of the phase and the absorption spectrum of the nanowires are reported. The electrodeposited nanowires (as prepared) had the preferred crystallite orientation of the α-phase. ITO formed the ohmic contact and Schottky contacts were formed between CuPc and aluminum. Insertion of a thin layer of PEDOT:PSS between CuPc nanowires and the ITO electrode improved the contact and reduced the series resistance by an order of magnitude. Schottky diodes were characterized and analyzed at room temperature and at cryogenic temperatures.
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Moturu, Sri Harsha. "SYNTHESIS AND CHARACTERIZATION OF P-TYPE COPPER INDIUM DISELENIDE (CIS) NANOWIRES EMBEDDED IN POROUS ALUMINA TEMPLATES." UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_theses/91.
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This work focuses on a simple template assisted approach for fabricating I-III-VI semiconductor nanowire arrays. Vertically aligned nanowires of p-CIS of controllable diameter and thickness are electrodeposited, from an acidic electrolyte solution, inside porous aluminum templates using a three electrode set up with saturated calomel electrode as the reference. AAO template over ITO-glass was used as starting template for the device fabrication. The deposited CIS is annealed at different temperatures in a reducing environment (95% Ar+ 5% H2) for 30 minutes. X-ray diffraction of the nanowires showed nanocrystalline cubic phase structures with a strong orientation in the <112> direction. The effective bandgap of the deposited CIS nanowires determined using the Near Infrared (NIR) Spectrometer was found to be 1.07eV. The type of CIS electrodeposited inside the porous alumina template is determined to be p-type from the Schottky diode obtained with ITO-CIS-Au structure. Schottky diodes were characterized and analyzed at room temperature.
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Yanamanagandla, Srikanth. "SYNTHESIS AND CHARACTERIZATION OF SCHOTTKY DIODES ON N-TYPE CdTe NANOWIRES EMBEDDED IN POROUS ALUMINA TEMPLATES." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_theses/573.
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This work focuses on the growth of vertically aligned CdTe nanowire arrays of controllable diameter and length using cathodic electro deposition in anodized alumina templates. This step was followed by annealing at 250° C in a reducing environment (95% Ar + 5% H2). AAO template over ITO-glass was used as starting template for the device fabrication. The deposited nanowires showed nanocrystalline cubic phase structures with a strong preference in [111] direction. First gold (Au) was deposited into AAO using cathodic electro deposition. This was followed by CdTe deposition into the pore. Gold was deposited first as it aids the growth of CdTe inside AAO and it makes Schottky contact with the deposited n type CdTe. CdTe was determined to be n-type from the fact that back to back diode was obtained with Au-CdTe-Au test structure. Aluminum (Al) was sputtered on the top to make the ohmic contact to the n type CdTe deposited in AAO. Analysis of Schottky diodes yielded a diode ideality factor of 10.03 under dark and 10.08 under light and reverse saturation current density of 34.9μA/cm2 under dark and 39.7μA/cm2 under light.
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Gravani, Styliani. "Synthesis of nanomaterials via anodic aluminium oxide templates." Thesis, University of Surrey, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616919.
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This thesis is concerned with the synthesis of 1 D nanomaterials via a template-assisted route. Porous anodic aluminium oxide templates prepared electrochemically have been utilised with two intrinsically different deposition techniques, sol-gel and high power pulsed magnetron sputtering (HPPMS), to obtain ID metal and metal oxide nanowires and nanotubes. The resultant morphologies and crystal structures were examined via SEM, XPS, XRD, TEM and EELS. A number of porous template alumina structures have been grown via the anodisation of pure and sputtered aluminium. The effects of surface pre-treatments, etching treatments and anodisation conditions on the resultant morphologies were investigated. It has been found that pore growth is largely dependent on the surface roughness of the substrate as well as the anodisation conditions. The anodisation duration is critical in promoting and allowing self-ordering. Obtained templates, varied in thickness from a few hundred run to several tens of pu-m, with an average pore diameter of 70 nm, interpore distance of 100 nm and pore density of 4 x 1010 cm2. . The implementation of HPPMS led to the successful deposition of Ti inside the alumina template to depths of around 45-50 run. It was found that templates with highly parallel pores on a rigid substrate such as Si, are more suited if this deposition method is to be used. Control of the pressure and substrate biasing is critical in avoiding 'pinch-off and 'bridging' and leading to complete pore filling. The results have shown that HPPMS is a promising plasma technology for the synthesis of nanomaterials such as nanodots, nanopillars or nanowires, when used with porous alumina templates under appropriate conditions. The use of sol-gel deposition has led to the growth of a number of interesting materials and structures. Nanocrystalline Ce02 and Ce1-xZrx02 and Ce1-xSmx02 thin films and powders have been successfully obtained exhibiting novel micro- and nano-structures, likely to find useful applications in catalysis and gas sensing due to their redox properties and large surface to volume ratio. FUlihermore, the treatment of porous alumina templates via a sol-gel/hydrothermal method led to the formation of Ce-doped y-Ah03 nanowires. Hence, a simple, direct and cost effective method for producing large scale Ah03 (and doped Ah03) nanowires is repotied. Moreover, by annealing at temperatures above 600 DC, nanowires of different crystallographic forms such as 0-, e- and a-Ah03 can also be readily obtained. As the dopant Ce was successfully introduced through this method a wide range of doped-Ah03 nanowires (by other rare eatihs such as Y, La, Gd, Srn), at various concentrations (e.g. 1,3,5 at. %) can be readily obtained.
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Baldé, Mamadou Saliou. "Etude et développement de microtechnologies sur substrat papier : application à la structuration d'AL2O3 poreux pour la faisabilité d'un capteur d'humidité." Thesis, Montpellier 2, 2013. http://www.theses.fr/2013MON20065.
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L'objectif premier de ce projet est la mise au point de procédés de fabrication microélectroniques/microtechnologiques compatibles avec l'utilisation d'un support papier. Pour cela, des techniques comme l'évaporation thermique sous vide, la photolithographie, l'électrodéposition et l'anodisation d'aluminium ont été développées et adaptées à ce support. Des bancs de caractérisations structurels, électriques et flexibles ont été aussi mis en œuvre pour étudier la fiabilité des couches déposées sur un tel substrat. En application, un capteur d'humidité à base d'oxyde d'aluminium flexible a été fabriqué et les tests en humidité ont montré d'excellents résultats permettant de valider le travail effectuéThe primary objective of this project is the implementation of microelectronics/microtechnology processes compatible with the use of paper-based substrate. For this purpose, techniques such as thermal vacuum evaporation, photolithography, electroplating and anodizing aluminum have been developed and adapted to this substrate. Structural, electrical and flexible characterizations benches have also been implemented to study the reliability of the layers deposited on such substrate. A moisture sensor based on flexible aluminum oxide was made and humidity tests have shown excellent results which validate the work
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El-Mashri, Saleh M. "Structure of anodic-oxide and hydrated oxide films on pure aluminium." Thesis, University of Warwick, 1985. http://wrap.warwick.ac.uk/108759/.
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The technique of electron yield-EXAFS has been used to derive information about the different structures of amorphous films, formed anodically on pure aluminium when various electrolyte solutions are used. It has been found that the uniform non-porous (barrier-type) oxide films which are formed in neutralised sodium tartrate or sodium borate electrolyte are amorphous and have an average Al-0 bond length of 0.190 nm. The amorphous oxide produced in neutralised sodium oxalate gives an average Al-0 separation of 0.185 nm, while the porous oxides formed in strong aggressive electrolytes, chromic acid and phosphoric acid, have an average Al-0 bond length of 0.183 nm and 0.180 nm respectively. Both the non-porous and the porous types of films have also been examined by high resolution scanning electron microscopy. The films formed in neutralised electrolytes show a structureless morphology, while the films prepared in strong acid are shown to have a porous morphology. All these oxide films become hydrated when exposed to hot water at 85°C. The time for complete hydration varies according to whether the film is porous or not. Electron yield-EXAFS analysis of these hydrated films yields two well defined Al-0 distances, 0.205 nm and 0.280 nm, which appear to be associated with the formation of an oxy-hydroxide similar in structure to boehmite. The SEM observation of these hydrated films shows a narked change in the micromorphology during hydration. A "cornflake" structure is developed which is related to the oxy-hydroxide structure (boehmite-like phase). These measured Al—O bond lengths derived from the EXAFS differ, depending on the nature of the anodising treatment, which suggests different states of aluminium-oxygen coordination. A possible model for the structure of amorphous alumina, based on this information, is proposed. These results are also discussed in relation to the structural chemistry of the hydration process.
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Ng, King-yeung, and 吳競洋. "An investigation of the deformation of anodic aluminium oxide nano-honeycomb during nanoindentation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42841240.
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Ng, King-yeung. "An investigation of the deformation of anodic aluminium oxide nano-honeycomb during nanoindentation." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B42841240.
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Lee, Jongmin [Verfasser], Ulrich [Akademischer Betreuer] Gösele, and Peter [Akademischer Betreuer] Woias. "Thermoelectric bismuth-related nanowires based on anodic aluminium oxide membranes / Jongmin Lee. Betreuer: Ulrich Gösele ; Peter Woias." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2009. http://d-nb.info/1024895629/34.
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Meyer, Daniel. "Korrelationen zwischen Herstellungsprozess, Struktur und Eigenschaften von anodischen Aluminiumoxidschichten für Verschleißschutzanwendungen." Doctoral thesis, Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-228257.
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Das Ziel dieser Dissertation besteht darin, einen Beitrag zur technologischen, ökonomischen und ökologischen Weiterentwicklung der anodischen Verfahren zur Oberflächenkeramisierung von Aluminium zu leisten. Die Arbeit ist in zwei thematische Schwerpunkte untergliedert. Im ersten Teil wird für die Hartanodisation eine hinsichtlich eines geringeren Energieeinsatzes optimierte Elektrolytzusammensetzung identifiziert und mit einem optimierten galvanostatischen Pulsmuster simultan appliziert. Im Ergebnis kann die Gesamtleistungsaufnahme um ca. 6 % reduziert werden, ohne die mechanischen Eigenschaften der Oxidschichten zu mindern. Im zweiten Schwerpunkt werden das Lichtbogen- und das Flammspritzen mit der plasmaelektrolytischen anodischen Oxidation kombiniert, um verschleißbeständige Aluminiumoxidschichten auf Stahl-, Titan- und Magnesiumsubstraten zu applizieren. Neben einer umfangreichen Mikrostrukturanalyse (REM, EDX, XRD, EBSD) werden die mechanischen Eigenschaften der Schichten untersucht und mit atmosphärisch plasmagespritzten Al2O3-Schichten verglichen. Insbesondere Oxidschichten auf lichtbogengespritztem AlCu4Mg1 zeigen dabei eine hohe Härte sowie eine sehr gute VerschleißbeständigkeitThe aim of the present work is to contribute to the technological, economic and ecological improvement of the anodic processes for the surface ceramization of aluminum. The work is subdivided into two thematic priorities. In the first part, for the hard anodizing process an optimized electrolyte composition for a lower energy input is identified and applied simultaneously with an optimized galvanostatic pulse regime. As a result, the total power consumption can be reduced by approximately 6% without reducing the mechanical properties of the oxide coatings. In the second focus, arc and flame spraying are combined with plasma electrolytic anodic oxidation to apply wear resistant aluminum oxide coatings on steel, titanium and magnesium substrates. In addition to a comprehensive microstructural analysis (SEM, EDX, XRD, EBSD), the mechanical properties of the layers are investigated and compared with atmospheric plasma sprayed Al2O3 coatings. In particular, oxide layers formed on arc sprayed AlCu4Mg1 coatings show a high hardness as well as very good wear resistance
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Singhal, Dhruv. "Forêt de nanofils semiconducteurs pour la thermoélectricité." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAY016/document.
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La conversion thermoélectrique a suscité un regain d'intérêt en raison des possibilités d'augmenter l'efficacité tout en exploitant les effets de taille. Par exemple, les nanofils montrent théoriquement une augmentation des facteurs de puissance ainsi qu'une réduction du transport des phonons en raison d'effets de confinement et/ou de taille. Dans ce contexte, le diamètre des nanofils devient un paramètre crucial à prendre en compte pour obtenir des rendements thermoélectriques élevés. Une approche habituelle consiste à réduire la conductivité thermique phononique dans les nanofils en améliorant la diffusion sur les surfaces tout en réduisant les diamètres.Dans ce travail, la caractérisation thermique d'une forêt dense de nanofils de silicium, germanium, silicium-germanium et alliage Bi2Te3 est réalisée par une méthode 3-omega très sensible. Ces forêts de nanofils pour le silicium, le germanium et les alliages silicium-germanium ont été fabriqués selon une technique "bottom-up" suivant le mécanisme Vapeur-Liquide-Solide en dépôt chimique en phase vapeur. La croissance assistée par matrice et la croissance par catalyseurs en or des nanofils à diamètres contrôlés ont été réalisés à l'aide d'alumine nanoporeuse comme matrice. Les nanofils sont fabriqués selon la géométrie interne des nanopores, dans ce cas le profil de surface des nanofils peut être modifié en fonction de la géométrie des nanopores. Profitant de ce fait, la croissance à haute densité de nanofils modulés en diamètre a également été démontrée, où l'amplitude et la période de modulation peuvent être facilement contrôlées pendant la fabrication des matrices. Même en modulant les diamètres pendant la croissance, les nanofils ont été structurellement caractérisés comme étant monocristallins par microscopie électronique à transmission et analyse par diffraction des rayons X.La caractérisation thermique de ces nanofils a révélé une forte diminution de la conductivité thermique en fonction du diamètre, dont la réduction était principalement liée à une forte diffusion par les surfaces. La contribution du libre parcours moyen à la conductivité thermique observée dans ces matériaux "bulk" varie beaucoup, Bi2Te3 ayant une distribution en libre parcours moyen (0,1 nm à 15 nm) très faible par rapport aux autres matériaux. Même alors, des conductivités thermiques réduites (~40%) ont été observées dans ces alliages attribuées à la diffusion par les surfaces et par les impuretés. D'autre part, le silicium et le germanium ont une conductivité thermique plus élevée avec une plus grande distribution de libre parcours moyen. Dans ces nanofils, une réduction significative (facteur 10 à 15 ) a été observée avec une forte dépendance avec la taille des nanofils.Alors que les effets de taille réduisent la conductivité thermique par une meilleure diffusion sur les surfaces, le dopage de ces nanofils peut ajouter un mécanisme de diffusion par différence de masse à des échelles de longueur atomique. La dépendance en température de la conductivité thermique a été déterminée pour les nanofils dopés de silicium afin d'observer une réduction de la conductivité thermique à une valeur de 4,6 W.m-1K-1 dans des nanofils de silicium fortement dopés avec un diamètre de 38 nm. En tenant compte de la conductivité électrique et du coefficient Seebeck calculé, on a observé un ZT de 0,5. Avec l'augmentation significative de l'efficacité du silicium en tant que matériau thermoélectrique, une application pratique réelle sur les appareils n'est pas loin de la réalitéThermoelectric conversion has gained renewed interest based on the possibilities of increasing the efficiencies while exploiting the size effects. For instance, nanowires theoretically show increased power factors along with reduced phonon transport owing to confinement and/or size effects. In this context, the diameter of the nanowires becomes a crucial parameter to address in order to obtain high thermoelectric efficiencies. A usual approach is directed towards reducing the phononic thermal conductivity in nanowires by achieving enhanced boundary scattering while reducing diameters.In this work, thermal characterisation of a dense forest of silicon, germanium, silicon-germanium and Bi2Te3 alloy nanowires is done through a sensitive 3ω method. These forest of nanowires for silicon, germanium and silicon-germanium alloy were grown through bottom-up technique following the Vapour-Liquid-Solid mechanism in Chemical vapour deposition. The template-assisted and gold catalyst growth of nanowires with controlled diameters was achieved with the aid of tuneable nanoporous alumina as templates. The nanowires are grown following the internal geometry of the nanopores, in such a case the surface profile of the nanowires can be modified according to the fabricated geometry of nanopores. Benefiting from this fact, high-density growth of diameter-modulated nanowires was also demonstrated, where the amplitude and the period of modulation can be easily tuned during the fabrication of the templates. Even while modulating the diameters during growth, the nanowires were structurally characterised to be monocrystalline through transmission electron microscopy and X-ray diffraction analysis.The thermal characterisation of these nanowires revealed a strong diameter dependent decrease in the thermal conductivity, where the reduction was predominantly linked to strong boundary scattering. The mean free path contribution to the thermal conductivity observed in the bulk of fabricated nanowire materials vary a lot, where Bi2Te3 has strikingly low mean free path distribution (0.1 nm to 15 nm) as compared to the other materials. Even then, reduced thermal conductivities (~40%) were observed in these alloys attributed to boundary and impurity scattering. On the other hand, silicon and germanium have higher thermal conductivity with a larger mean free path distribution. In these nanowires, a significant reduction (10-15 times) was observed with a strong dependence on the size of the nanowires.While size effects reduce the thermal conductivity by enhanced boundary scattering, doping these nanowires can incorporate mass-difference scattering at atomic length scales. The temperature dependence of thermal conductivity was determined for doped nanowires of silicon to observe a reduction in thermal conductivity to a value of 4.6 W.m-1K-1 in highly n-doped silicon nanowires with 38 nm diameter. Taking into account the electrical conductivity and calculated Seebeck coefficient, a ZT of 0.5 was observed. With these significant increase in the efficiency of silicon as a thermoelectric material, a real practical application to devices is not far from reality
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Sieber, Maximilian. "Elektrochemisches Modell zur Beschreibung der Konversion von Aluminium durch anodische Oxidation." Doctoral thesis, Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-216761.
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Durch elektrochemische Impedanzspektroskopie während der anodischen Oxidation von Aluminium werden in der vorliegenden Arbeit die elektrochemischen Vorgänge während der Oxidbildung quantitativ und zeitabhängig untersucht. Es wird ein Modell vorgeschlagen und diskutiert, welches das Impedanzverhalten während der anodischen Oxidation in Schwefel-, Oxal- und Phosphorsäure über einen großen Bereich von Konzentrationen und Stromdichten abbilden kann. Aus den gewonnenen Ergebnissen werden die kapazitive Wirkung der Sperrschicht am Porengrund, der Eintritt von Ladungsträgern in die Sperrschicht, der Ionentransport durch die Sperrschicht sowie die Oxidbildungsreaktion selbst als wesentlich für das Impedanzverhalten identifiziert. Die ermittelten Zusammenhänge und Konstanten können als Grundlage für Modellvorstellungen dienen, welche das Verhalten elektrischer Prozessgrößen und die Ausbildung der charakteristischen Oxidstruktur bei der anodischen Oxidation von Aluminium verknüpfenIn the present work, the electrochemical subprocesses of the oxide formation on aluminium by anodic oxidation are investigated using electrochemical impedance spectroscopy. The time dependence of the impedance behaviour and the quantitative relations between the process parameters and the impedance behaviour are considered. A model for the representation of the electrochemical behaviour during the anodic oxidation in sulphuric, oxalic and phosphoric acid is proposed and discussed for a wide range of anion concentrations and current densities. On the basis of the obtained results, the capacitive effect of the barrier layer, the charge transfer resistance of the barrier layer, the ion transport within the barrier layer and the oxide formation are identified as the dominating effects for the impedance behaviour. The established relations can serve as a basis for models, which interrelate both the electrochemical behaviour and the geometrical formation of the characteristic pore structure
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Chennell, Philip. "Préparation et caractérisation de surfaces poreuses ordonnées en polymères en vue d'applications médicales." Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAS005/document.
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Les stents urétéraux et les sondes de néphrostomie sont constitués de silicone ou de polyuréthane thermoplastique (TPU). Afin de limiter les risques infectieux lors de leur implantation, une modification topographique par création de pores permettrait de limiter l’adhésion des bactéries et de former des réservoirs pour une libération in situ de substances antiinfectieuses. Ce travail vise à préparer des surfaces en polymère ayant un motif poreux tubulaire ordonné. Une réplication en deux temps à partir de surfaces ordonnées poreuses d’oxyde d’aluminium (PAAO) préparées par 2 méthodes (double anodisation douce et double anodisation dure/douce) a été mise en œuvre pour reproduire le motif initial sur des surfaces en silicone et TPU. Pour le moule intermédiaire trois matériaux ont été testés (acrylonitrile butadiène styrène, polystyrène et résine polyacrylate). Les surfaces ont toutes été caractérisées par des techniques microscopiques et spectroscopiques. Les surfaces en PAAO préparées par double anodisation douce possédaient des pores d’environ 50 nm de diamètre et 100 nm de profondeur, alors que celles obtenues après mise au point de la méthode dure/douce étaient de taille supérieure, d’environ 125 nm de diamètre et ayant des profondeurs de quelques centaines de nanomètres. La surface du moule intermédiaire est constituée de picots. Une adhésion latérale de ceux-ci a été observée pour certaines conditions. La meilleure réplication du motif a été obtenue pour le TPU. Les surfaces ainsi obtenues pourront être utilisées et optimisées lors de l'étude ultérieure de l'adhésion du biofilmUreteral stents and nephrostomy catheters are made of silicone or thermoplastic polyurethane (TPU). A topographical modification creating an ordered porous surface could limit the infectious risks during their implantation, by reducing bacterial adhesion and creating a loading platform from which anti-infectious compounds could be released.In this work, a two-steps replication method was used to create ordered porous polymer surfaces (silicone or TPU) using porous anodic aluminium oxide (PAAO) as master template. The PAAO surfaces were prepared by double mild or double hard/mild anodization. Three intermediate mould materials were tested (acrylonitrile butadiene styrene, polystyrene, polyacrylate resin). The polymer material (silicone or TPU) was then moulded onto the intermediate mould surfaces that possessed freestanding pillar arrays, to imprint pores. The obtained surfaces were characterized by microscopic and spectroscopic methods. The initial PAAO surfaces prepared by double mild anodization possessed pores of about 50 nm diameter and 100 nm depth, whereas those prepared after development of the double hard/mild anodization method were bigger, of about 125 nm diameter and several hundred nanometers deep. The intermediate mould structure possessed freestanding arrays, but instabilities (lateral adhesion) were noted for certain conditions. The best pattern replication was observed for TPU. In conclusion, these novel porous polymeric surfaces could be optimized and tested for an anti-biofilm effect
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Silva, Karina Rodrigues da. "Caracterização da alumina anódica porosa modificada por plasma." Universidade Federal de São Carlos, 2015. https://repositorio.ufscar.br/handle/ufscar/8331.
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In this study, the wettability of porous anodic alumina (PAA) surfaces modified by plasma was investigated. The porous anodic alumina films were grown on aluminum substrate using a two step anodization procedure in oxalic acid solution under potentiostatic regime. The surfaces of PAA films were modified by plasma treatment or plasma deposition techniques. Prior to surface modification, the impurities were removed by a plasma cleaning procedure. Oxygen was used in plasma treatment in order to produce hydrophilic surfaces. On the other hand, the plasma deposition (in HMDSO or HMDSO + argon mixture) was performed to produce hydrophobic surfaces or less hydrophilic surface. Electropolished aluminum without PAA film were used as reference. The influence of substrate morphology on wettability was analyzed. The morphological characterization was performed by scanning electron microscopy (SEM). The microstructural analysis was carried out using Fourier Transformed Infrared Spectroscopy (FTIR). A goniometer was used to measure the contact angle and evaluate the wettability of electroplished aluminum and PAA films. The results showed that the wettability of the samples was affect by chemical interactions of functional groups on the surface deposited after plasma treatment. The effect of the porous surface morphology on wettability was not significant compared to the plasma treated films with new chemical interactions effects.
Neste trabalho foram investigadas as propriedades de molhabilidade das superfícies nanoestruturadas da alumina anódica porosa (AAP) modificadas por plasma. Os filmes de AAP foram produzidos sobre substrato de alumínio pelo método de anodização potenciostática em duas etapas em solução de ácido oxálico. Após a fabricação, as amostras foram submetidas a um tratamento a plasma (com oxigênio) ou a deposição a plasma (em HMDSO ou em uma mistura de HMDSO e argônio). Antes das modificações das superfícies, removeram-se as impurezas das amostras através de técnicas de limpeza a plasma. No tratamento a plasma, o gás oxigênio foi utilizado para a obtenção de superfícies hidrofílicas. Por outro lado, para tornar a superfície hidrofóbica ou menos hidrofílica, foram feitas duas séries de deposição a plasma, uma contendo uma mistura de argônio e HMDSO e outra série somente com HMDSO. O tratamento ou deposição a plasma também foram feitas em amostras de alumínio eletropolido, sem a camada de AAP, a fim de verificar a influência morfológica do substrato na molhabilidade. A caracterização morfológica dos filmes de AAP foi feita por microscopia eletrônica de varredura (MEV), onde foi verificada a formação dos poros na superfície. A caracterização microestrutural foi feita por espectroscopia de absorção no infravermelho por transformada de Fourier (FTIR) com o objetivo de verificar as alterações químicas na superfície. A molhabilidade foi analisada utilizando um goniômetro, equipamento que realiza medição direta do ângulo de contato. Os resultados mostram que a molhabilidade da superfície é afetada por interações químicas dos grupos funcionais na superfície dos filmes. Por outro lado, o efeito da morfologia sobre a molhabilidade da superfície não é significativo nas condições estudadas.
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Johansson, Anders. "Template-Based fabrication of Nanostructured Materials." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7364.
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Appusamy, Boopathy Harish, and Pavan Kumar Bonthala. "Electrochemical etching and anodizing as key stages of surface treatment of aluminium foil for electrolytic capacitor industry : Application of Electro Chemical Impedance Spectroscopy as non-destructive characterization of etched anode foil with an anodized dielectric oxide layer." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Produktutveckling, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-37858.
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In the initial stage, the sample preparation was done by using the techniques of Anodic etching and anodic forming processes where a repeated trial and error method of sample preparation headed towards making out a suitable sample set for characterization. After this step, the set of 2 different industrial samples were introduced and anodic oxide forming process was carried out in different electrolytes. In the sample preparations, 4 different electrolytes were used 15% wt. Ammonium Adiphate, 1.5% wt. Ammonium Phosphate, 7% wt. Boric acid and 15% Penta Borate at different stages for performing the anodic oxide forming process. Minimum forming voltages of 20V to a maximum of 100V was employed in the sample preparation and to overcome the waiting time in forming the etched samples a higher current of 0.5A was used. After the samples preparation, Electrochemical Impedance spectroscopy was used as a tool for characterising the various groups of samples and for observing the micro structures of various samples, they were fractured and the observed on the cross section by SEM. After the analysis of the etched samples was made, an attempt to compare the results of the data of these samples to that of the 2 set of industrial samples was made and found that the resultant data wasn’t stable enough to characterize since huge scattering were occurring and whereby the simulation of the CPE circuit for the chosen circuit in the analysis was not possible. Under the analysis, a randomly chosen industrial sample was also used and the resultant data was utilised in understanding the response of the system to different electrolytes.Sammanfattning Avhandlingsarbetet har genomförts på KEMET AB i samarbete med yttekniklaboratoriet vid JTH i syfte att karakterisera den etsade anodiska aluminiumfolien som grundprov med anodisering och etsning för ytbehandling. I inledningsskedet gjordes provberedningen med användning av teknikerna för anodisk etsning och anodbildande processer där en upprepad provnings- och felmetod för provberedning ledde ut mot att utarbeta en lämplig provuppsättning med avseende på karakterisering. Efter detta steg infördes uppsättningen av 2 olika industriella prover och anodoxidbildande process utfördes i olika elektrolyter. I provpreparaten användes 4 olika elektrolyter 15 % vikt Ammoniumadiphat, 1,5 vikt% Ammoniumfosfat, 7 vikt% Borsyra och 15 % Penta-borat vid olika steg för utförande av anodoxidbildningsförfarandet. Minimala formningsspänningar på 20V till ett maximum av 100V användes i provframställningen och för att övervinna väntetiden vid bildning av de etsade proven användes en högre ström av 0,5A. Efter provberedningen användes elektrokemisk impedansspektroskopi som ett verktyg för att karakterisera de olika grupperna av prover och för att observera mikrostrukturerna i olika prover, de bröts och de observerades i tvärsnittet av SEM. Efter att analysen av de etsade proverna gjordes ett försök att jämföra resultaten av data från dessa prover till den för de två uppsättningarna av industriella prover. Det är konstaterat att de resulterande data inte var stabila nog att karakterisera eftersom stor spridning inträffade och varigenom simuleringen av CPE-kretsen för den valda kretsen i analysen inte var möjlig. Under analysen användes också ett slumpmässigt valt industriellt prov och de resulterande data användes för att förstå systemets respons till olika elektrolyter.
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Hsing, Meng-Hann, and 辛孟翰. "Application of Anodic Aluminum Oxide(AAO) in Nanoimprint Lithography." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/97224671442220669328.
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碩士中國文化大學
機械工程學系數位機電碩士班
100
The advantage of anodic aluminium oxide (AAO) is low cost, high productivity, large area, and simple fabrication. Different spacing of holes are used in every low dimension’s regular nano material. The AAO is widely applied to fabrication of low-dimension nano materials for various diameter of holes and distance between the holes. Firstly, based on Taguchi methods, we have investaged the impacts of temperature, distance between electrodes, time, and applied voltage in the anodic process. For the orthogonal table of L9 layout, the best setting of AAO process could be achieved. Secondly, We present the new mold fabrications for nanoimprint lithography for the application of ordered array of rod or pore patterning. The concave and convex types of the mold are achieved. For this technology, the master is required preparation before the mold fabrication. The master is utilized by step and repeated to achieve the structures over a large area on the mold. The master, mold, and imprint results demonstrate that the new approaches of mold fabrication could be a feasible scheme with low cost and high throughput.
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Wang, Yadong, Melissa Sander, Chen Peng, Soo-Jin Chua, and Clifton G. Jr Fonstad. "GaN Based Nanomaterials Fabrication with Anodic Aluminium Oxide by MOCVD." 2003. http://hdl.handle.net/1721.1/3664.
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A highly self-ordered hexagonal array of cylindrical pores has been fabricated by anodizing a thin film of Al on substrate and subsequent growth of GaN and InGaN in these nanoholes has been performed. This AAO template-based synthesis method provides a low cost process to fabricate GaN-based nanomaterials fabrication.Singapore-MIT Alliance (SMA)
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Su, Bo Ren, and 蘇柏任. "The research of anodic aluminum oxide(AAO) template coated strontium titanate." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/11486335791804431165.
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碩士國立勤益科技大學
機械工程系
98
In this paper, our research is that the surface of AAO naropores is coated using spin coating machine. First of all, the surface of aluminum is becomes smooth, after electrochemical polishing and machine grinding. To produce changes in the pore size controlling, we process first anodizing method using the method of oxalic acid, sulfuric acid and phosphoric acid, and the holing wall is more regular after the second anodizing method. Observing the surface diameter of the holes, it can be found in the pore size of oxalic acid is about 60 ~ 70nm, sulfuric acid pore size of about 20 ~ 30nm, phosphate pore size of about 300nm. Due to the strontium titanate cannot be directly coated to nanopores by spin coating method, so we use chemical solvents to remove the nanoporous, leaved bow-type shape is coated on the surface, Mixed with different molar concentrations (1Mole and 3Mole) for spin coating made of strontium titanate, recrystallization strontium titanate thin film is formed using liquid of strontium titanate mixed with erbium, the rotation of spin coating, the heating temperature and time parameters. By the Scanning Electron Microscopy (SEM) observation of AAO pore size, film thickness, Energy Dispersive Spectrometer (EDS), X-ray Diffraction (XRD), X-ray spectrometer around the radio frequency crystal structure and element, and PL Fluorescence Spedtrometers ( PLFS) to measure the strontium titanate peak intensity of visible light range. Experimental data show that the strontium titanate is coated on surface of AAO nanopores and aluminum, AAO template coated strontium titanate is more higher visible light intensity than aluminum, we heat 3mole strontium titanate to 650 ℃, then the film is formed, the peak intensity is 160(a.u.), in the worst case, we heat to 500 ℃, peak strength of 1 mole strontium titanate is 85 (a.u.), molar concentration and the temperature of heat treatment will also affect the peak intensity of visible light, The higher peaks increases as the temperature, so heating temperature influence the formation of crystalline thin-film luminescence intensity. Contacting angle measurement results show that the angle is 91.18 degrees, and it is greater than 90 degrees for the hydrophobic structure.
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Chen, Chin-Hsing, and 陳進興. "Fabrication of Anodic Aluminum Oxide (AAO) for Dye-Sensitized Solar Cell (DSSC)." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/66537310518597249408.
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碩士國立交通大學
理學院碩士在職專班應用科技學程
97
In this study, we used commercial aluminum 1070 sheet (99.7% Aluminum) as the substrate. After anodization process, a high quality, uniform pore size, and regular anodic aluminum oxide template was produced. Moreover, the chemical deposition method was employed to hydrolyze and deposit titanium fluoride (TiF4) into the AAO template,to make titanium dioxide(TiO2) of dye sensitized solar cells was electron transfer layer,then the coaxial nanotube structure consisting of aluminum oxide and titanium oxide was obtained. On the other hand, immersing the nanotube in dye-sensitizer solution was the first process to obtain the anode of dye sensitized solar cell (DSSC).The fundamental sandwich structure of NT-DSSCs device composes of a cathode with sputter of transparent platinum catalyst, the anode with multiaxial type titanium dioxide/N3 dye and electrolyte (I-/I3-). The fabrication of AAO was formed by anodic oxidation of aluminum in different acid-based electrolytes, such as sulfuric acid, oxalic acid and phosphoric acid, which could synthesize the nanotube diameters of 18nm, 60nm and 200nm, respectively. By widening AAO pores, the template with uniform and regular pores, which were varied from 25nm to 500nm could be produced.
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Lee, Bao-Ying, and 李寶英. "A nanoporous small Anodic Aluminum Oxide (AAO) tube for long-acting drug release." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/21211963046846832506.
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碩士國立中興大學
機械工程學系所
103
The objective of this study is to develop a long-acting and implantable drug-release device that can effectively control the release rate and concentration of the loaded drug. The proposed device consists of a tubular nanoporous anodic aluminum oxide (AAO) encapsulating a microporous chitosan/collagen composite. The nanopore size of the AAO tube can be modified by adjusting the anodization parameters, which in turn adjust the release rate and concentration, while the microporous chitosan/collagen composite provides the long-acting release feature. Fabrication results indicate that the AAO tube has a uniform pore arrangement with a pore size around 50 nm. The synthesized microporous chitosan/collagen composite containing 90% chitosan yielded the highest moisture content and was therefore used as the drug carrier. Release experiments demonstrate that the proposed long-acting drug-release device had released less than 65% of the loading drug on the 17th release day. We then applied the proposed long-acting drug-release scheme as a recombinant human-bone morphogenetic-protein 2 (rh-BMP2) release device to induce differentiation of pre-osteoblast MC3T3-E1 cells into osteoblasts. Results from alkaline phosphate (ALP) and alizarin red S assays demonstrate that the total amount of rh-BMP2 consumed by the proposed AAO tube is much less than that consumed using the conventional culture approach. Furthermore, our approach has the advantage of requiring only one-time dosing, whereas the conventional approach requires the periodic renewal of rh-BMP2. AAO’s one-time dosing feature combined with its biocompatablity and biodegradability can be beneficial in real implant applications.
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LEE, CHANG-HSUAN, and 李常鉉. "Using Anodic Aluminum Oxide (AAO) as a Template to Fabricate Nanostructured materialson Silicon Substrate." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/43667976751342365992.
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碩士國立交通大學
材料科學與工程系所
93
In this research, we fabricate the anodic aluminum oxide (AAO) templates of different parameters on the silicon substrates: In order to get nanopores with two different sizes, we use two kinds of electrolyte such as oxalic acid and sulfuric acid separately; to change the anodic voltage to adjust the inter-pore distance; to change the pore-widening time to adjust the pore size; to change the duration of the second anodic process to adjust the aspect ratio of templates. And we grow AAO templates selectively by depositing silicon oxide as the anodization barrier layer. In order to grow carbon nanotubes (CNTs) assisted by AAO templates, we deposit a Ni thin film between AAO and silicon substrate for catalyst in this research. We synthesize CNTs in the thermal CVD system using a process gas mixture of C2H4 and H2 in this template, and measure the field emission property of them. And then we study the influence of growth of CNTs and field emission properties by changing the process gas flows. Furthermore, we deposit a TaN thin film between AAO and silicon substrate. And then we synthesize TaOx nano-pillar arrays in the bottom of AAO nanopores by using the anodic oxidization process. The field emission and high dielectric properties of nano-pillar will be studied in the future.
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Chen, Feng-Lin, and 陳峰霖. "Fabrication of Anodic Aluminum Oxide (AAO) Array Using Sulfuric/Oxalic Acid Mixture as Electrolyte." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/10538957903218510195.
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碩士國立清華大學
材料科學工程學系
93
The self-organized anodic aluminum oxide mask provides low cost, high throughput, large scale and fundamentally simple processes to creat periodic nanostructures. Camparing with using the tranditional electrolytes, electropolished Al foils were anodized by two-step anodization in sulfuric/oxalic acid mixture with different proportion as electrolyte at different applied voltages to induce the ordered structure in a wilder range of interpore distance. The morphologies of these samples were examined by scanning electron microscope (SEM). In the thesis, different interpore distances (82, 78, 66, 63, and 58 nm) of ordered porous alumina were carried out by anodization in different proportional sulfuric/oxalic acid mixture solution as electrolyte at specific voltages (33, 29, 26, 24, and 21V). Other acids as electrolyte were also used in the experiment. On the other hand, the titanium oxide nanodots with 96nm interval and silicon oxide nanodots with 65nm interval were prepared successively from Al/Ti films on silicon substrate and Al film on silicon substrate by locally electrochemical anodization. Ordered Pt and Ni nanodots arrays with spacing distance of 100nm were fabricated using ultra-thin (~100nm) porous alumina as a mask by sputter deposition and evaporation deposition, respectively. After annealing Pt particles under 800°C, the shape of Pt nanostructure changes from disc to spherical-dot shape. Moreover, large ranged of highly ordered Ni nanowires with shape anisotropic magnetic properties were synthesized by electrodeposition by using high-aspect-ratio porous alumina as template. The length of appearance nanowire tips can be easily adjusted by wet etching in NaOH solution for suitable time. This approach offers considerable versatility in the choice of materials.
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Hung, Jui-Yi, and 洪瑞易. "Nanostructures Fabricated by Anodic Aluminum Oxide (AAO) Templation Method for Electron Field Emission Applications." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/96005007262383059474.
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碩士國立交通大學
材料科學與工程系所
95
For the past two decades, electron field emission devices have attracted much attention because of their potential applications for cold cathode flat panel display and vacuum microwave devices. Among various electron field emitters, the Spindt type microfabricated emitter has been extensively investigated for applications of the cold cathode field emitter. In this study, we fabricated highly ordered nanostructured field emitter array using porous anodic aluminum oxide (AAO) as the template. Two types of nanostructured field emitters were prepared: the titanium nitride (TiN) nanopillar emitter array and the iridium oxide (IrO2) coated Si nanocone emitter array. In order to fabricate ordered emitter array, a TiOx nanodot array was first prepared as the nanomask for subsequent fabrication of nanoemitters. The AAO template was used to regulate the formation arrangement of the TiOx nanomaks, with which nanoemitters were then fabricated using conventional integrated circuit process technology. For fabrication of the TiN nanopillar emitter array, TiN and Al were sequentially sputter-deposited on the Si substrate followed by electrochemical anodization of the film stack, thereby the TiOx nanodot array was produced. After reactive-ion-etching the underlying TiN layer using the TiOx nanodots as the mask, TiN nanopillars can be formed with a pattern arrangement in compliant with the AAO pattern. The TiN nanopillars had a ridge-shaped edge on the top after the removal of the TiOx nanomasks. Field emission characteristics of the TiN nanopillar array were studied under a vacuum condition of 10-6 torr. The TiN nanopillars emitters had a very low turn-on voltage while the Fowler-Nordheim plot showed a nonlinear field-emission behavior. The nonlinearity was ascribed to that the ridge-shaped top edge produced field emission before the rest of the emitting area. For fabrication of Si nanocone emitters, similar processes were performed as the fabrication processes of the TiN nanopillars excepted for the thinner thickness of the TiN film. After removal of the AAO template, the TiOx nanodots and the remanent TiN thin film were subject to reactive-ion-etching processes, and the formed TiN nanopillars were used as the mask to prepare the Si nanocone array in a high-density-plasma-reactive-ion-etching (HDP-RIE) system. In order to obtain chemically stable field emitters with a high field-emission efficiency, IrO2 was deposited on the Si nanocones by pulsed anodic electrodeposition. The tip radius and the sharpness of the field emitter were highly dependent on the electrodeposition conditions, such as the pulse waveform, period and the applied current. Field emission characteristics of the IrO2 coated Si nanocone array were also studied, and showed a better field emission performance than that of the bare Si nanocone emitter array.
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Chuang, Chih-Chen, and 莊之箴. "Characteristics of AlN Film Using DC Magnetron Sputtering on Anodic Aluminum Oxide (AAO) Substrate." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/7fh4m8.
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碩士中原大學
電子工程研究所
106
In this study, The Aluminum Nitride (AlN) was deposited by reactive DC magnetron sputtering method on Anodic Aluminum Oxide (AAO) substrates to investigate the relationship between the quality of AlN thin film and related process conditions. AAO films were fabricated by a two-step anodization process. High purity (99.9995%) aluminum foils was anodized in oxalic acid solution or phosphoric acid solution. Graphite rod as cathode. The anodizing potential and anodization time are controlled to obtain different pore diameter of AAO substrates. The AlN thin film deposited on AAO substrates has similar effect to Epitaxial Lateral Overgrowth (ELO). SEM, AFM, XRD and ellipsometry were used to study the relationship between film formation mechanism, surface morphology, crystallization characteristics and optical properties of the film and the structure of AAO substrate. In summary, AlN thin film grown on AAO substrates has been proved with high C-axis preferred orientation. Moreover, it is found that the quality of AlN film is inversely proportional to the difference between AAO pore diameter and twice pore wall thickness ( | Dp－2tw | ). The AlN thin film on AAO_50 substrate has the largest refractive index (2.106) and the minimum FWHM (0.20528°).
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Chun, Chang Kai, and 張凱鈞. "Using Anodic Aluminum Oxide (AAO) as a Template to Fabricate Carbon Nanotube Field Emitter Arrays." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/56479953918375812461.
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碩士國立交通大學
材料科學與工程系所
94
For the practical field emission display (FED) applications, growth of vertically aligned carbon nanotubes (CNTs) as field emitters is very essential. However, with the traditional synthesis methods, CNTs usually show poor arrangement and disordered direction. To grow CNTs as field emitters for FED applications, we utilize nanoporous anodic aluminum oxide (AAO) with highly ordered pore channels to template the growth of CNT field emitter arrays. The AAO template is prepared by two-step anodization of the Al film on the silicon substrate. After electro-deposition of the Co catalyst on the bottom of the AAO pore channel, multiwall CNTs were synthesized in electron-cyclotron-resonance chemical-vapor-deposition (ECR-CVD) system using the gas mixture of CH4 and H2. CNTs thus prepared were highly aligned because the nanopore channels of the AAO template constrained the CNTs growth along the axis of the pore channels, and CNTs overgrown out of the pore surface remained in the vertical growth direction due to the applied DC bias and the plasma self-bias under the ECR plasma condition. The growth rate of CNTs in the AAO template by ECR-CVD is considerably low, and therefore, the tube length can be suitably controlled by tuning the growth time. In addition, the CNTs tube number density was found to be a function of the Co electro-deposition time. The number of CNTs extending out of AAO nanopores increases linearly with the Co electro- deposition time. On the contrary, the tube number density of CNTs on the Al film decreases with reducing the Co electro-plating time. The field emission property of CNT arrays was investigated in an electrical measurement system under a vacuum condition of 10-6 torr. The electrical measurement showed that the field emission of the AAO-CNT emitter arrays followed Fowler-Nordheim (F-N) field emission behavior. In this work, the carbon nanotube field emission triode was fabricated by two methods, which will be described in the thesis. With the assistant of the AAO template, the mono-dispersed CNTs array in triode structures showed good alignment and well controlled tube number density. The fabrication methods of the CNT-triode structure used in our research are suitable for large-area substrates. The large-area fabrication capability is essential for the implementation of this AAO-CNT triode structure in the FED technology for industrial purpose.
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汪砡華. "Preparation of Different Anodic Aluminum Oxide (AAO) Templates on Silicon Substrates for the Growth of Carbon Nanotubes (CNTs)." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/xmn2rj.
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碩士國立交通大學
材料科學與工程系所
92
Recently, synthesis of CNTs using an anodic aluminum oxide (AAO) template has drawn much attention because this method allows precise and reproducible control of the dimension of CNTs. In this study, we extended two types of AAO template methods to the patterned growth of CNTs on a silicon wafer, which is desirable for a direct application to microelectronics, by electroless Ni plating in AAO pores and preparing the layered structure of AAO template on a Ni-coated wafer. The silicon wafer prevents AAO templates from warping and cracking during thermal treatment. For this purpose, three types of AAO templates, [AAO / Al / Si], [AAO / Si], and [AAO / Ni / Si] templates, uniformly without barrier layer at the bottom of the pores were formed. Moreover, for the purpose of controlling CNT density, two pore sizes of AAO were fabricated. In addition, to achieve the goal of growing CNT selectively, we have demonstrated two methods to grow AAO selectively. One is to form aluminum pads before anodization, the other method is to form an anodization barrier pattern before anodization. Based on these techniques, AAO templates would potentially offer much broader application.
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Lin, Kai-Heng, and 林楷恆. "Development of Seamless Roller with Anodic Aluminum Oxide (AAO) Nano-Structures with its Application on Roller Hot Embossing." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/18441289207523215569.
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碩士國立臺灣大學
機械工程學研究所
99
Nanostructured thin films have been widely applied for anti-reflective components and self-cleaning surfaces. The roller mold for production of nanostructured films mostly relies on expensive processes, such as e-beam or focused ion beam. This study develops an effective, fast, and low-cost method to fabricate seamless anodic aluminum oxide (AAO) roller mold, which then be employed to fabricate nanostructures on the surface of polycarbonate (PC) continuously by roller hot embossing. The alumina oxide membranes with nanopores of 80 nm, 160 nm and 430 nm in pitches were fabricated via two-step anodization, and the employed anodization voltage are 40 V, 80 V and 180 V, respectively. The SEM photos show that the fabricated nanopores are similar as observed from all degrees of the surface. However, there are microholes on the surface due to the purity of the aluminum is only 99%. The aluminum with higher purity, including a 99.999% purity aluminum foil and a roller which were sputter coated with a 99.99% purity aluminum layer, were anodized in this research. The result show that using higher purity aluminum could obtain anodic aluminum oxide with better arrangement and without microholes on surface because less impurities exist. The seamless AAO roller mold fabricated in this research has been utilized to continuous hot rolling process. Comparing to plate form hot embossing, hot rolling has the advantage of high speed, continuous, large area, and suit for mass production. Since the mold itself is seamless, in this work, the nanostructures on the AAO roller mold can be replicated onto the PC substrate with no restriction of length and seam defect, providing the nanostructured films various ways of application.
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Neubacher, Henrik. "Pore-spanning lipid membranes as a tool to study membrane permeabilization by antimicrobial peptides." Doctoral thesis, 2017. http://hdl.handle.net/11858/00-1735-0000-0023-3EF3-B.
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Mejia, Elkin. "Fabrication of a tapered porous structure in anodic aluminum oxide (AAO) tubular membrane using a two-step anodization process." 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1463951.
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Tao, Chung-Wei, and 陶仲威. "Achieving sub-wavelength imaging through a flat hyperlens composed of silver nanowires in a modified anodic aluminum oxide (AAO) template." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/85727290139518006681.
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Савченко, С. С., and S. S. Savchenko. "Люминесцентные свойства и фотометрические характеристики наноструктур с квантовыми точками InP/ZnS : магистерская диссертация." Master's thesis, 2016. http://hdl.handle.net/10995/43867.
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В работе проведено исследование оптических характеристик коллоидных квантовых точек (КТ) InP/ZnS различных размеров (QD-1, QD-2, QD-3) и композитных наноструктур анодированного оксида алюминия (AAО) с КТ методами спектрофотометрии и люминесцентной спектроскопии.
Выполнен литературный обзор, касающийся электронных состояний в идеальном нанокристалле (НК), синтеза КТ на основе InP, использования НК для создания нанокомпозитов и расчёта цветовых характеристик излучателей. Описаны методики подготовки образцов и проведения измерений спектров оптического поглощения (ОП) и фотолюминесценции (ФЛ).
По анализу спектров ОП КТ определены значения энергий оптических переходов. Полосы с наименьшей энергией соответствуют первому экситонному пику поглощения ядра InP. Другие могут быть приписаны оболочке из ZnS. По синему сдвигу осуществлена оценка размера ядер образцов КТ. Для QD-1 исследована температурная зависимость первого экситонного пика поглощения. Спектры ФЛ позволяют предположить, что полосы свечения формируются как экситонными переходами, так и дефектами кристаллической решётки ядра InP.
Синтезирован ряд структур нанопористого оксида алюминия, отожженного при различных температурах, с осаждёнными КТ и исследована их ФЛ. Показано, что после осаждения в AAО НК InP/ZnS, сохраняют свои флуоресцентные свойства, следовательно, можно говорить об успешном создании композитных люминофоров InP/ZnS@AAO. Обсуждаются цветовые характеристики изучаемых образцов.This study deals with the investigation of optical characteristics of differently sized InP/ZnS colloidal quantum dots (QD-1, QD-2, QD-3) and composite nanostrucrures of anodic aluminum oxide with QDs by means of spectrophotometry and luminescence spectroscopy techniques. The literature review concerning electronic states in an ideal nanocrystal (NC), synthesis of InP-based QDs, use of NCs for creating nanocomposites and calculating color characteristics of emitters was carried out. The methods of sample preparation and measurements of optical absorption (OA) and photoluminescence (PL) spectra are described. Values of optical transition energies are determined according to the analysis of QD OA spectra. The bands with the lowest energy correspond to the first exciton absorption peak of the InP core. The other transitions can be attributed to the ZnS shell. The core size of the QD samples was evaluated using the blue shift. The temperature dependence of the first exciton absorption peak was investigated for the QD-1. PL spectra of QDs indicate that the emission bands are formed by exciton transitions and defects of the InP crystal lattice. A series of structures of nanoporous aluminum oxide, annealed at different temperatures, with deposited QDs were synthesized and their PL were studied. Fluorescent properties of the QDs are found to be retained after the deposition, therefore, InP/ZnS@AAO composite phosphors were successfully created. Сolor characteristics of the samples under study are discussed.
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Yang, Kun-lin, and 楊昆霖. "Fabrication of Large Area Anodic Alumina Oxide (AAO) Arrays and Its Applications." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/wm94d6.
Full textAbstract:
碩士國立中山大學
光電工程研究所
95
The AAO membrane with nanopore arrays were fabricated by anodizing highly pure aluminum foils (99.9995%) in electrolyte. Ordered array have been obtained under optimized anodizing condition, and pore diameter can be controlled by different anodic voltage and electrolyte. After we got such an ordered arrangement porous alumina array, the following analysis of the material optical properties were characterized. Photoluminescence measurements showed a strong PL peak in blue. The PL peak was 420nm excited by He-Cd laser. From the transmittance spectra, the results showed that material was transparent above 400nm. The XRD spectra of AAO without and with annealing, both showed the diffraction peaks of (311)、(400)、(440), corresponding to the γ-Al2O3 phase appear. High ordered anodic porous alumina with holes interval 65nm was prepared in mixture solution of H3PO4 and H2SO4 under high temperature and high concentration. Through the use of porous anodic alumina masks, nanopore arrays were fabricated on Si、GaAs substrates by reactive ion etching. Also, metal nanodot arrays were formed through the AAO mask by evaporation. Thin AAO slabs also enhance the light extraction from the QDs, and control the PL emission wavelength.
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Chih, Hung Chung, and 鍾志鴻. "The Investigation of Growing Carbon Nanotubes (CNTs) on Anodic Alumina Oxide (AAO) with Chemical Vapor Deposition." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/88496519951080750268.
Full textAbstract:
碩士中國文化大學
材料科學與奈米科技研究所
94
In this thesis, we grow carbon nanotubes on anodic alumina oxide (AAO) substrate by electro-deposited Nickel, Iron and Lanthanum catalysts in its pores. Because anodic alumina oxide (AAO) its pores are highly ordered. We anodized the aluminum thin film two times and penetrate pores to contact with the buffer layer of substrate by reversed-bias method. By this way, it can provide the better connection for electric current and electron field emission. Carbon nanotubes, which were grown with Nickel, Iron and Lanthanum catalysts, the amounts of carbon nanotubes will increase when we prolong the time. In the all processing, the diameters of nanotubes are limited to the pores’ sizes and it is independently growing time. It means that the pores’ dimension can provide one way to control the nanotubes diameters by controlling the catalysts’ size. And this thesis is the first one that we successfully grew nanotubes with Lanthanum metal catalyst. We analyzed the Raman Spectrum of nanotubes, which are growing with three kinds of catalysts and several processing times. The spectrum data shows that the ratio of ID/IG. is decrease with the processing time. It means the crystallization of samples is better when the ratio of ID/IG. is decreasing. Comparing the several carbon nanotubes grown with three kinds catalysts, it showed the better results by using Iron and Lanthanum catalysts. We can improve the electron field emission by using these two catalysts. It can advance the efficacy of electron field emission. By using anodic alumina oxide (AAO) substrate as nanoscale templates, we electro-deposited three kinds catalysts into its pores in order to control CNTs’ diameter and distance, which can avoid the shielding effect. Because the buffer layer “titanium” can provide for electrode within refilled the catalyst and better connections for field emission, so that it can ameliorate the current density of field emission. With the basic CVD, we have successfully grown highly ordered and well-functioned CNTs’ substrate.
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Liao, Ruei-Chang, and 廖瑞章. "The Study of Growth Kinetics of Anodic Aluminium Oxide and the Analysis of Electrochemical Characteristics." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/73147783672935408443.
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Tseng, Chun-Wei, and 曾俊瑋. "Preparation, Structure and Anti-Reflective Properties of Nano-Porous Anodic Aluminium Oxide for Solar Cell Application." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/wxk58a.
Full textAbstract:
碩士國立東華大學
光電工程學系
100
While it has been known that the electrochemical behavior of the ions migration (Al3+ and O2−) for pore AAO formation can conventionally be distinguished by controlling the voltage-time curve, the effects of geometric scale dependent reflectance on the optical properties of AAO films have not been emphasized until recent years. In addition, the nano-porous AAO with pore-density/size dependent anti-reflectance (AR) at different incident angles has rarely been addressed. In particular, the alternative approach on simplifying the AR film evaporation with lower production cost is also the important key for obtaining cost-effective solar cells, whereas more than 34% of the incident light is actually reflected back from the surface of solar cells. This study demonstrates nanoporous AAO thin films with ultra-low reflectivity and hydrophobicity on glass substrate produced by two-step anodization at room temperature. The effects of various electrochemical conditions on their geometric scale and the reflectance at different incident angles are characterized. In particular, the surface energy related hydrophobicity, as well as the geometric scale of the electrochemical synthesized nanoporous AAO film, is investigated and elucidated. By electro-polishing the aluminum coating, a minimum roughened surface with an Rrms of 3.91 nm is obtained. After adjusting the applied potential, an optimum regular structure of anodic aluminum oxide (AAO) is obtained, corresponding to the pore diameter and density of 23 nm and 8.67×10^10 cm^-2. In particular, nanoporous AAO with an air/solid ratio of 58% exhibits a maximum water contact angle of 73.4° corresponding to surface energy of 40.1×10^-5 N．cm^-1. Furthermore, the TM-mode reflection analysis shows a diminishing Brewster angle shifted from 60°-54° with an increasing air/solid ratio from 37%-58% at 532 nm. The greatly reduced small-angle reflectance and surface energy reveals a nonlinear trend with an enlarging pore size and air/solid ratio, leading to a minimum surface reflectance and maximum water contact angle at the nanoporous AAO prepared with 60V. Furthermore, an optimum power efficiency of 1.13% is obtained in the nanoporous AAO anti-reflection coating glass covered semi-manufactured solar cell.
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Wang, Ye. "Synthesis of Anodic Alumina Nanotubes for Drug Delivery and Nanotoxicity Study: understanding of bio-nano interactions by a nanomaterial model." Thesis, 2015. http://hdl.handle.net/2440/119467.
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Nanomedicines, which utilize nano-sized drug-carriers so-called nanoparticles to load therapeutic drugs for selective cancer targeting and treatment, are promising therapeutics for fighting cancer. Unfortunately, although achieving commercial success, the first generation of nanomedicines only showed limited improvement of cancer therapy in clinical practice. In this situation, the fabrication of novel nanomedicines has been and will continue to be an important approach for improving cancer therapeutics. It is equally important to understand the paradigms and mechanisms of nanotoxicity in order to minimize or eliminate the potential toxicological consequence of synthetic nanomaterials to the living organism and environment. In this thesis, a new model nanomaterial, so-called anodic alumina nanotubes (AANTs) were synthesised for the study of nanotoxicity and drug delivery. Firstly, an advanced nanofabrication technique so-called pulse anodization was intensively studied in this thesis for structurally engineering anodic aluminium oxide (AAO) nanostructures. This enabled the production of AAO-based nanophotonics (i.e. microcavities) as well as AANTs. Then, systematic studies were conducted on the toxicological properties and drug delivery applicability of AANTs toward cancer therapy. This 3-year PhD project not only sheds new light on the fabrication of novel AAO-based nanostructures by pulse anodization, but also expands our knowledge and understanding in the field of nanotechnology, cancer biology, drug delivery and nanotoxicity. The AANTs-based nanotoxicity and drug delivery studies also highlight the potential of this novel nanomaterial for biomedical applications. Key word: drug delivery, nanotoxicity, cancer therapy, nanotube, anodic aluminium oxide, anodization, cancer biologyThesis (Ph.D.) -- University of Adelaide, School of Chemical Engineering & Advanced Materials, 2015
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Mohammed, Hanan. "Cylindrical Magnetic Nanowires Towards Three Dimensional Data Storage." Diss., 2018. http://hdl.handle.net/10754/630141.
Full textAbstract:
The past few decades have witnessed a race towards developing smaller, faster,
cheaper and ultra high capacity data storage technologies. In particular, this race
has been accelerated due to the emergence of the internet, consumer electronics,
big data, cloud based storage and computing technologies. The enormous increase
in data is paving the path to a data capacity gap wherein more data than can be
stored is generated and existing storage technologies would be unable to bridge this
data gap. A novel approach could be to shift away from current two dimensional
architectures and onto three dimensional architectures wherein data can be stored
vertically aligned on a substrate, thereby decreasing the device footprint. This thesis
explores a data storage concept based on vertically aligned cylindrical magnetic
nanowires which are promising candidates due to their low fabrication cost, lack of
moving parts as well as predicted high operational speed. In the proposed concept,
data is stored in magnetic nanowires in the form of magnetic domains or bits which
can be moved along the nanowire to write/read heads situated at the bottom/top of
the nanowire using spin polarized current.
Cylindrical nanowires generally exhibit a single magnetic domain state i.e. a
single bit, thus for these cylindrical nanowire to exhibit high density data storage, it
is crucial to pack multiple domains within a nanowire. This dissertation
demonstrates that by introducing compositional variation i.e. multiple segments
along the nanowire, using materials with differing values of magnetization such as
cobalt and nickel, it is possible to incorporate multiple domains in a nanowire. Since
the fabrication of cylindrical nanowires is a batch process, examining the properties
of a single nanowire is a challenging task. This dissertation deals with the
fabrication, characterization and manipulation of magnetic domains in individual
nanowires. The various properties of are investigated using electrical
measurements, magnetic microscopy techniques and micromagnetic simulations.
In addition to packing multiple domains in a cylindrical nanowire,
this dissertation reports the current assisted motion of domain walls along
multisegmented Co/Ni nanowires, which is a fundamental step towards achieving a
high density cylindrical nanowire-based data storage device.
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Meyer, Daniel. "Korrelationen zwischen Herstellungsprozess, Struktur und Eigenschaften von anodischen Aluminiumoxidschichten für Verschleißschutzanwendungen." 2016. https://monarch.qucosa.de/id/qucosa%3A20771.
Full textAbstract:
Das Ziel dieser Dissertation besteht darin, einen Beitrag zur technologischen, ökonomischen und ökologischen Weiterentwicklung der anodischen Verfahren zur Oberflächenkeramisierung von Aluminium zu leisten. Die Arbeit ist in zwei thematische Schwerpunkte untergliedert. Im ersten Teil wird für die Hartanodisation eine hinsichtlich eines geringeren Energieeinsatzes optimierte Elektrolytzusammensetzung identifiziert und mit einem optimierten galvanostatischen Pulsmuster simultan appliziert. Im Ergebnis kann die Gesamtleistungsaufnahme um ca. 6 % reduziert werden, ohne die mechanischen Eigenschaften der Oxidschichten zu mindern. Im zweiten Schwerpunkt werden das Lichtbogen- und das Flammspritzen mit der plasmaelektrolytischen anodischen Oxidation kombiniert, um verschleißbeständige Aluminiumoxidschichten auf Stahl-, Titan- und Magnesiumsubstraten zu applizieren. Neben einer umfangreichen Mikrostrukturanalyse (REM, EDX, XRD, EBSD) werden die mechanischen Eigenschaften der Schichten untersucht und mit atmosphärisch plasmagespritzten Al2O3-Schichten verglichen. Insbesondere Oxidschichten auf lichtbogengespritztem AlCu4Mg1 zeigen dabei eine hohe Härte sowie eine sehr gute Verschleißbeständigkeit.The aim of the present work is to contribute to the technological, economic and ecological improvement of the anodic processes for the surface ceramization of aluminum. The work is subdivided into two thematic priorities. In the first part, for the hard anodizing process an optimized electrolyte composition for a lower energy input is identified and applied simultaneously with an optimized galvanostatic pulse regime. As a result, the total power consumption can be reduced by approximately 6% without reducing the mechanical properties of the oxide coatings. In the second focus, arc and flame spraying are combined with plasma electrolytic anodic oxidation to apply wear resistant aluminum oxide coatings on steel, titanium and magnesium substrates. In addition to a comprehensive microstructural analysis (SEM, EDX, XRD, EBSD), the mechanical properties of the layers are investigated and compared with atmospheric plasma sprayed Al2O3 coatings. In particular, oxide layers formed on arc sprayed AlCu4Mg1 coatings show a high hardness as well as very good wear resistance.
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Sieber, Maximilian. "Elektrochemisches Modell zur Beschreibung der Konversion von Aluminium durch anodische Oxidation." Doctoral thesis, 2016. https://monarch.qucosa.de/id/qucosa%3A20624.
Full textAbstract:
Durch elektrochemische Impedanzspektroskopie während der anodischen Oxidation von Aluminium werden in der vorliegenden Arbeit die elektrochemischen Vorgänge während der Oxidbildung quantitativ und zeitabhängig untersucht. Es wird ein Modell vorgeschlagen und diskutiert, welches das Impedanzverhalten während der anodischen Oxidation in Schwefel-, Oxal- und Phosphorsäure über einen großen Bereich von Konzentrationen und Stromdichten abbilden kann. Aus den gewonnenen Ergebnissen werden die kapazitive Wirkung der Sperrschicht am Porengrund, der Eintritt von Ladungsträgern in die Sperrschicht, der Ionentransport durch die Sperrschicht sowie die Oxidbildungsreaktion selbst als wesentlich für das Impedanzverhalten identifiziert. Die ermittelten Zusammenhänge und Konstanten können als Grundlage für Modellvorstellungen dienen, welche das Verhalten elektrischer Prozessgrößen und die Ausbildung der charakteristischen Oxidstruktur bei der anodischen Oxidation von Aluminium verknüpfen.In the present work, the electrochemical subprocesses of the oxide formation on aluminium by anodic oxidation are investigated using electrochemical impedance spectroscopy. The time dependence of the impedance behaviour and the quantitative relations between the process parameters and the impedance behaviour are considered. A model for the representation of the electrochemical behaviour during the anodic oxidation in sulphuric, oxalic and phosphoric acid is proposed and discussed for a wide range of anion concentrations and current densities. On the basis of the obtained results, the capacitive effect of the barrier layer, the charge transfer resistance of the barrier layer, the ion transport within the barrier layer and the oxide formation are identified as the dominating effects for the impedance behaviour. The established relations can serve as a basis for models, which interrelate both the electrochemical behaviour and the geometrical formation of the characteristic pore structure.