Dissertations / Theses on the topic 'Nanofabrication'
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Miles, Jessica. "Atomic Nanofabrication with Chromium." Thesis, University of Manchester, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516404.
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Rius, Suñé Gemma. "Electron beam lithography for Nanofabrication." Doctoral thesis, Universitat Autònoma de Barcelona, 2008. http://hdl.handle.net/10803/3404.
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La litografía por haz de electrones (Electron Beam Lithography, EBL) se ha consolidado como una de las técnicas más eficaces que permiten definir motivos en el rango nanométrico. Su implantación ha permitido la nanofabricación de estructuras y dispositivos para su uso en el campo de la nanotecnología y la nanociencia.La EBL se basa en la definición de motivos submicrónicos mediante el rastreo de un haz energético de electrones sobre una resina. La naturaleza de los electrones y el desarrollo the haces extremadamente finos y su control preciso establecen la plataforma ideal para los requerimientos de la Nanofabricación. El uso de la EBL para el desarrollo de un gran número de nanoestructuras, nanodispositivos y nanosistemas ha sido, y continúa siendo, crucial para las aplicaciones de producción de máscaras, prototipaje o dispositivos discretos para la investigación fundamental. Su éxito radica en la alta resolución, flexibilidad y compatibilidad de la EBL con otros procesos de fabricación convencionales.
El objetivo de esta tesis es el avance en el conocimiento, desarrollo y aplicación de la EBL en las areas de los micro/nanosistemas y la nanoelectrónica. El presente documento refleja parte del trabajo realizado en el Laboratorio de Nanofabricación del Instituto de Microelectrónica de Barcelona IMB-CNM-CSIC durante los últimos cinco años. Debido a la falta de experiencia previa en el IMB en la utilización de la EBL, ha sido necesario el desarrollo y consolidación de una serie de procesos, lo que ha condicionado parcialmente la investigación, tal y como recoge la memoria.
Entre los aspectos relevantes compilados en esta tesis, en cuanto a innovación tecnológica, cabe destacar diversos avances en procesos tecnológicos basados en la EBL. Una nueva resina de tono negativo ha sido caracterizada y disponible para su uso en nanofabricación. La optimización de la EBL se ha llevado a cabo mediante métodos de corrección del efecto de proximidad. Se ha establecido el proceso de integración de estructuras nanomecánicas en circuitos CMOS, así como la fabricación de dispositivos basados en nanotubos de carbono. En concreto, el primer FET basado en un sólo nanotubo de carbono fabricado en España. Finalmente, la compatibilidad y viabilidad de los métodos de fabricación basados en haces de partículas se ha estudiado mediante el análisis del efecto de los haces de partículas cargadas sobre dispositivos. Por otro lado, esta memoria no sólo contiene la descripción de los principales resultados obtenidos, sinó que pretende aportar información general sobre procesos de nanofabricación basados en haces de electrones para ser utilizados en futuras investigaciones de este area.
Electron beam lithography (EBL) has consolidated as one of the most common techniques for patterning at the nanoscale meter range. It has enabled the nanofabrication of structures and devices within the research field of nanotechnology and nanoscience.
EBL is based on the definition of submicronic features by the scanning of a focused energetic beam of electrons on a resist. The nature of electrons and the development of extremely fine beams and its flexible control provide the platform to satisfy the requirements of Nanofabrication. Use of EBL for the development of a wide range of nanostructures, nanodevices and nanosystems has been, and continues to be, crucial for the applications of mask production, prototyping and discrete devices for fundamental research and it relies on its high resolution, flexibility and compatibility with other conventional fabrication processes.
The purpose of this thesis is to advance in the knowledge, development and application of electron beam lithography in the areas of micro/nano systems and nanoelectronics. In this direction, this memory reflects part of the work performed at the Nanofabrication Laboratory of the IMB-CNM. Since there was no previous experience on EBL at CNM, the need for developing a set of processes has determined partially the work.
The variety of topics that concern to nanoscience and nanotechnology is enormous. Chapter 1 briefly sintetizes nanoscale related aspects. This section aims to frame the contents of this thesis, coherently. Also for completeness, it is intended to address the specific subjects under discussion or contained in the following chapters and it is based or oriented to the experimental results that will be presented.
Chapter 2 is a general overview of the EBL technique from the point of view of the system and the physical interaction of the process. In particular, the characteristics of the SEM and specifications of the lithographic capabilities of the system that is used are presented.
In chapter 3, irradiation effect on resists is studied. The chemical behaviour of different polymeric materials is correlated with theoretical simulations for two types of resists: methacrylic based positive resists and epoxy based negative resists. The first is used for validation of the modelization and to describe the general performance of EBL on different conditions. The second covers the experiments oriented to establish the performance parameters of a new resist and comparison with another existing negative electron beam resist. Proximity effect correction concludes with the correlation of theory and experimental results for both types of resists, positive and negative.
Chapter 4 is an example of the fabrication and optimization of a micro/nanosystem for sensing at the nanoscale. In particular, nanoresonators are developed with two approaches (EBL and FIB) and enhanced response is achieved by their integration on CMOS circuitry.
Chapter 5 presents carbon nanotube (CNT) based devices that are realized and implemented for applications in nanoelectronics and sensing. First, different fabrication approaches for contacting CNTs are discussed. Then, the results of electrical characterization of the devices are presented. Finally, technology development for the use of these devices for sensing is established.
The last chapter embraces all the previous sections and pays attention to the effect of electron beam on the devices. In particular, electron induced effect is studied on nanomechanical structures integrated in circuits and CNT based devices, in order to evaluate EBL based fabrication, SEM characterization or more fundamental aspects. Advanced characterization techniques are used together with simulations, both assessing a deeper understanding of the results. Electrical measurements and AFM based techniques are used to characterise the effect of the electron irradiation by changes in their performance characteristics, charging, surface potential imaging, etc.
Main results and solved challenges are summarized in the conclusive chapter 7 that finishes with this document.
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Latif, Adnan. "Nanofabrication using focused ion beam." Thesis, University of Cambridge, 2000. https://www.repository.cam.ac.uk/handle/1810/34605.
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Focused ion beam (FIB) technique uses a focused beam of ions to scan the surface of aspecimen, analogous to the way scanning electron microscope (SEM) utilizes electrons. Recent developments in the FIB technology have led to beam spot size below 10 nm,which makes FIB suitable for nanofabrication. This project investigated thenanofabrication aspect of the FIB technique, with device applications perspective inseveral directions. Project work included construction of an in-situ FIB electricalmeasurement system and development of its applications, direct measurements ofnanometer scale FIB cuts and fabrication and testing of lateral field emission devices. Research work was performed using a number of materials including Al, Cr, SiO2, Si3N4and their heterostructures. Measurements performed included in-situ resistometricmeasurements, which provided milled depth information by monitoring the resistancechange of a metal track while ion milling it. The reproducibly of this method wasconfirmed by repeating experiments and accuracy was proven by atomic force microscopy(AFM). The system accurately monitored the thickness of 50 nm wide and 400 nm thick(high aspect ratio) Nb tracks while ion milling them. Direct measurements of low aspectratio nanometer scale FIB cuts were performed using AFM on single crystal Si,polycrystalline Nb and an amorphous material. These experiments demonstrated theimportance of materials aspects for example the presence of grains for cuts at this scale. Anew lateral field emission device (in the plane of the chip) was fabricated, as FIB offersseveral advantages for these devices such as control over sharpness and decrease in anodeto-cathode spacing. FIB fabrication achieved field emission tip sharpness below 50 nm andanode-to-cathode spacing below 100 nm. For determining the field emission characteristicsof the devices, a low current (picoampere) measurement system was constructed anddevices operated in ultra high vacuum (10-9 mbar) in picoampere range. One devicefabricated using a FIB sharpening process had a turn on voltage of 57 V.
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Dibos, Alan. "Nanofabrication of Hybrid Optoelectronic Devices." Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:17463975.
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The material requirements for optoelectronic devices can vary dramatically depending on the application. Often disparate material systems need to be combined to allow for full device functionality. At the nanometer scale, this can often be challenging because of the inherent chemical and structural incompatibilities of nanofabrication. This dissertation concerns the integration of seemingly dissimilar materials into hybrid optoelectronic devices for photovoltaic, plasmonic, and photonic applications. First, we show that combining a single strip of conjugated polymer and inorganic nanowire can yield a nanoscale solar cell, and modeling of optical absorption and exciton diffusion in this device can provide insight into the efficiency of charge separation. Second, we use an on-chip nanowire light emitting diode to pump a colloidal quantum dot coupled to a silver waveguide. The resulting device is an electro-optic single plasmon source. Finally, we transfer diamond waveguides onto near-field avalanche photodiodes fabricated from GaAs. Embedded in the diamond waveguides are nitrogen vacancy color centers, and the mapping of emission from these single-photon sources is demonstrated using our on-chip detectors, eliminating the need for external photodetectors on an optical table. These studies show the promise of hybrid optoelectronic devices at the nanoscale with applications in alternative energy, optical communication, and quantum optics.Engineering and Applied Sciences - Applied Physics
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Yang, Yong. "Carbon dioxide assisted polymer micro/nanofabrication." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1117591862.
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Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xviii, 226 p.; also includes graphics (some col.). Includes bibliographical references (p. 206-226). Available online via OhioLINK's ETD Center
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Hurley, Fergus (Fergus Gerard). "Advanced nanofabrication of thermal emission devices." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44454.
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Includes bibliographical references (p. 89-91).Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.
Nanofabricated thermal emission devices can be used to modify and modulate blackbody thermal radiation. There are many areas in which altering thermal radiation is extremely useful, especially in static power conversion, lighting and sensor applications. Two specific thermal emission devices which show great promise include resonant thermal emitters and selective thermal emitters. It has been found from theory that resonant thermal emitters exhibit quasi-monochromatic and partially coherent thermal emission when fabricated with a 2-dimensional photonic crystal structure in a high-dielectric low-absorption material such as silicon. This type of fabricated resonant thermal emitter has great potential for use as near-IR and IR sensors. Theory has also shown that selective thermal emitters fabricated in tungsten with a 2-dimensional photonic crystal structure can exhibit spectrally selective thermal emission. This type of fabricated selective thermal emitter can be used to increase the efficiency of thermophotovoltaic (TPV) systems by preventing the incident thermal radiation below the band-gap of the PV diode from reaching the PV diode. This thesis explores the nanofabrication of a 2-dimensional photonic crystal silicon-on-sapphire (SOS) resonant thermal emitter which is now possible to fabricate due to advances in fabrication technology. Initially, the theory behind the SOS resonant thermal emitter which exhibits multiple resonant emission peaks is discussed. Next, an in-depth examination of the theory behind the technology used in the fabrication the resonant thermal emitter is investigated. Then, the SOS resonant thermal emitter fabrication process and characterization which was performed is discussed. The results showed that it was possible to fabricate the required 2-dimensional pattern but that there were issues with the pattern transfer into silicon, which needs to be further researched.
by Fergus Hurley.
S.M.
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Speaks, Rachel Suzanne. "High-resolution pattern transfer for nanofabrication." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616072.
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Roller, Eric Tobias. "Nanofabrication with the scanning tunnelling microscope." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624355.
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Moraes, Isabelle Gomes de. "Nanofabrication de nanocomposites magnétiques dur-doux." Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALY042.
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Cette thèse présente le développement et la caractérisation d'échantillons modèles pour l'étude des nanocomposites (NC) magnétiques dur-doux. Ces matériaux sont d'un grand intérêt, compte tenu de leurs applications potentielles en tant qu'aimants haute performance. Cependant, malgré ce grand potentiel, les propriétés des NC dur-doux rapportées dans la littérature sont modestes par rapport à celles prédites par les modèles micromagnétiques. Dans ce travail, nous utilisons des outils avancés de nanofabrication et de caractérisation pour développer des échantillons modèles, susceptibles de faire le lien de entre les simulations et les expériences. Quatre réseaux différents de nano-bâtonnets magnétiques doux allongés (FeCo ou Co) (épaisseur = 10 nm) ont été produits par lithographie électronique et évaporation. Pour étudier l'influence du contenu et des dimensions des nano-bâtonnets, la largeur (w) a été modifiée entre 25 et 120 nm, la longueur (l) entre 200 et 400 nm et la distance inter-bâtonnets (d) entre 50 et 200 nm. Le rapport volumique de la phase douce varie de 2 à 11%. Tous les nano-bâtonnets ont été couverts d'une couche de 3 nm d'Au afin d'éviter l'oxydation lors du transfert de l'échantillon de la lithographie vers les chambres de dépôt. La couche d’or a été gravée dans la chambre de pulvérisation juste avant le dépôt de la couche magnétique dure (FePt-25 ou 50 nm) au-dessus des nano-bâtonnets. Une seconde étape de lithographie a été développée pour limiter la localisation de la phase magnétique dure à l'endroit où se trouvent les réseaux de nano-bâtonnets. Une cellule élémentaire du NC a une surface d'environ 5x5 µm2, et cette cellule est répétée pour avoir une surface d'échantillon globale de quelques mm2, dont le signal magnétique est suffisant pour les mesures de magnétométrie globale. Un processus de recuit post-croissance favorise la formation de la phase magnétique dure L10 FePt . Plus la fraction volumique de nano-bâtonnets est élevée, plus la coercivité est faible et plus la rémanence est élevée. Des courbes de retournement du premier ordre (FORC) ont été obtenues pour les échantillons avec une fraction volumique comparable de phase magnétique douce, mais avec une taille de nano-bâtonnets différente. Bien que les échantillons aient des cycles d'hystérésis similaires, les diagrammes FORC montrent que les distributions de champ de retournement sont assez distinctes. La fabrication et l'analyse d'un échantillon de référence avec des nano-bâtonnets non magnétiques de Pt n'indiquent aucune influence de la topographie globale de l'échantillon sur les propriétés de la matrice dure. L'imagerie TEM et la cartographie chimique des coupes transversales préparées par FIB ont révélé une diffusion de type Kirkendall dans les NC avec les plus petits nano-bâtonnets. Une étude MFM sur la même cellule élémentaire de NC dans différents états rémanents , a été réalisée sur des réseaux de NC (dur / doux et dur / non magnétique) et un film de micro-motifs durs (.i.e. pas de nano-bâtonnets). L'évolution des motifs magnétiques a été corrélée avec les champs de fuite produits par la matrice magnétique dure et les nano-bâtonnets intégrés. Les résultats obtenus avec des méthodes de caractérisation magnétique globale (cycles d'hystérésis et FORC) et locale (MFM), combinés à une caractérisation structurale détaillée obtenue par TEM, ont permis d'analyser l'impact des dimensions, de la périodicité, de la concentration et du matériau constitutif des nano-bâtonnets intégrés dans la matrice magnétique dure. Le compromis entre réduire les dimensions de la phase douce pour favoriser le couplage d'échange et les augmenter pour minimiser la diffusion pendant le recuit pour former la formation de phase dure, est un point critique pour le développement de ces matériaux modèlesThis thesis presents the development and characterization of model samples for the study of hard-soft magnetic nanocomposites. These materials are of great interest, considering their potential applications as high performance magnets. However, even with this great potential, the properties of hard-soft nanocomposites reported in the literature are modest compared to those predicted by micromagnetic models. In this work, we use advanced nanofabrication and characterization tools to develop model samples, capable of bridging the understanding between models and experiments. Four different arrays with elongated soft magnetic nano-rods (FeCo or Co) (thickness = 10 nm) were produced by e-beam lithography and evaporation. To study the influence of the content and the dimensions of the nano-rods, the width (w) was varied between 25 and 120 nm, the length (l) between 200 and 400 nm and the inter-rod distance (d) between 50 and 200 nm. The volume content of the soft phase ranged from 2 to 11%. All the nano-rods were capped with a 3 nm layer of Au in order to prevent oxidation during sample transfer from the lithography to the deposition chambers. The Au layer was etched in the sputtering chamber just prior to deposition of the hard magnetic layer (FePt- 25 or 50 nm) on top of the nano-rods. A second lithography step was developed to limit the location of the hard magnetic phase to where the nano-rods arrays are positioned. A unit piece of the nanocomposite has a surface area of roughly 5x5 µm2, and the unit was repeated to have an overall sample surface area of a few mm2 , to have sufficient magnetic signal for global magnetometry measurements. A post-annealing process promotes the formation of the L10 FePt hard magnetic phase. The higher the volume content of nano-rods, the lower the coercivity and the higher the remanence. First Order Reversal Curves (FORC) were obtained for the samples with comparable volume content of soft magnetic phase, but with different nano-rod size. Although the samples have similar hysteresis cycles, the FORC diagrams show that the switching field distributions are quite distinct. The sample with nano-rod width = 120 nm shows switching fields extending up to 250 mT and a single peak around µ0HC = 0 T, while the sample with nano-rod width = 25 nm has two peaks in switching field, centred at µ0HC = 0 T and µ0HC = 500 mT. Fabrication and analysis of a reference sample with Pt non-magnetic nano-rods indicates no influence of the overall sample topography on the hard matrix properties. TEM imaging and chemical mapping of FIB-prepared cross sections revealed Kirkendall-like diffusion in the nanocomposites with the smallest nano-rods. An MFM study which involved probing the same nanocomposite unit in different remnant states, was carried out on nanocomposites arrays (hard/soft and hard/non-magnetic) and a micro-patterned hard film (.i.e. no nano-rods). The experimental setup included a homemade in-situ in-plane pulsed magnetic field source. The evolution in magnetic patterns was correlated with the stray fields produced by the hard magnetic matrix and the embedded nano-rods. The results obtained with global (hysteresis loops and FORC) and local (MFM) magnetic characterization methods, combined with detailed structural characterization obtained by TEM, made it possible to analyze the impact of dimensions, periodicity, concentration, and the constituent material of the nano-rods embedded in the hard magnetic matrix. A trade-off between reducing the dimensions of the soft phase to favour exchange coupling and increasing them to minimize diffusion during annealing to form the hard phase formation, is a bottleneck for the development of these model materials
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Lindblom, Magnus. "Nanofabrication of Diffractive Soft X-ray Optics." Doctoral thesis, KTH, Biomedicinsk fysik och röntgenfysik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9800.
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This thesis summarizes the present status of the nanofabrication of diffractive optics, i.e. zone plates, and test objects for soft x-ray microscopy at KTH. The emphasis is on new and improved fabrication processes for nickel and germanium zone plates. A new concept in which nickel and germanium are combined in a zone plate is also presented. The main techniques used in the fabrication are electron beam lithography for the patterning, followed by plasma etching and electroplating for the structuring of the optical materials. The process for fabricating nickel zone plates has been significantly improved. The reproducibility of the electroplating step has been increased by the implementation of an in-situ rate measurement and an end-point detection method. We have also shown that pulse plating can be used to obtain zone plates with a uniform height profile. New plating mold materials have been introduced and electron-beam curing of the molds has been investigated and implemented to increase their mechanical stability so that pattern collapse in the electroplating step can be avoided. The introduction of cold development has improved the achievable resolution of the process. This has enabled the fabrication of zone plates with outermost zone widths down to 16 nm. The nickel process has also recently been adapted to fabrication of gold structures intended for test objects and hard x-ray zone plates. For the fabrication of germanium zone plates we developed a highly anisotropic plasma-etch process using Cl2 feed and sidewall passivation. Germanium zone plates have been fabricated with zone widths down to 30 nm. The diffraction efficiency is comparable to that of nickel zone plates, but the process does not involve electroplating and thus has for potential for highyield fabrication. The combination of nickel and germanium is a new fabrication concept that provides a means to achieve high diffraction efficiency even for thin nickel. The idea is to fabricate a nickel zone plate on a germanium film. The nickel zone plate itself is then used as etch mask for a highly selective CHF3- plasma etch into the germanium layer. Proof of principle experiments showed an efficiency increase of about a factor of two for nickel zone plates with a 50- nm nickel thickness.QC 20100728
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Abdelaziz, Ramzy [Verfasser]. "Green Nanofabrication at Leidenfrost Condition / Ramzy Abdelaziz." Kiel : Universitätsbibliothek Kiel, 2015. http://d-nb.info/1069290084/34.
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Li, Chang-Peng. "Nanofabrication, nanomagnetism and other applications of nanostructures." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2007. http://wwwlib.umi.com/cr/ucsd/fullcit?p3277801.
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Thesis (Ph. D.)--University of California, San Diego, 2007.Title from first page of PDF file (viewed October 10, 2007). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 116-123).
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Gnanavel, Thirunavukkarasu. "Nanofabrication techniques for nickel and cobalt nanostructures." Thesis, University of Sheffield, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.556680.
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The aim of this work is to explore novel ways of nanofabrication for nickel and cobalt nanostructures. This has been achieved using conventional as well as new methods. Novel electron beam sculpting by ablation of atoms is utilised for two-dimensional (2D) thin film nanostructuring and three-dimensional (3D) nanostructuring as well. Electron beam lithography (EBL) is explored mainly for thin film nanostructuring for nanojunction formation. Electron beam induced phase transformation or electron beam fabrication of nanoparticles and nanobeads are shown to be innovative and successful methods for fabrication of nanopartic1e assemblies. An electron beam sculpting method was successfully tested to produce nanostructures such as nanohole arrays, nanolines, nanoelectrodes and nanojunctions on a cross-sectional transmission electron microscopy (XTEM) specimen. A novel 3D nanofabrication method (tomographic nanofabrication) has been introduced using a high-tilt tomographic holder with example on an electrochemically etched nickel nanotip sharpening. The EBL produced nanojunctions were found to be better to realise sub-25 nm sized structures while electron beam sculpting has been shown to be superior to realise sub-5 nm dimensional structures. Further, a combination of EBL and electron beam sculpting techniques is worked out for realising sub-5 nm structures. A new nanoparticle or nanobead synthesis method has been introduced using transition metal fluorides (NiF2 and CoF2) as the starting material. An electron beam of a TEM depletes tluorine from the transition metal fluoride fragment quickly compared to the metal depletion, which results in the metal end product. Depending on the beam condition (acceleration voltage, intensity of the beam and beam focusing techniques) it was possible to tune the final end product into a singular or a few nanobead(s) or a distribution of nanoparticles. The produced nanobeads of 100-1000 nm size showed stacking faults and grain boundaries. In most of the cases, these nanobeads consist of multiply twined-nanograins. On the other hand, the achieved nanopartic1es mostly consist of metallic Ni or Co nanocrystals of 1-100 nm in size. This simplest, non-hazardous, oxide-free fabrication method offers great potential for laboratory-scale research.
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Chong, Boon Keat. "Nanofabrication of magnetic scanned-probe microscope sensors." Thesis, University of Glasgow, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394955.
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Hasan, Farhan. "Conductive resists for nanofabrication on insulating substrates." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7858/.
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The purpose of this work is to support ongoing miniaturization of III-V microelectronic devices, which present a unique combination of economic and technical challenges. As miniaturization has proceeded photolithography has been able to meet required 20 nm feature sizes through the use of increasingly complex optical engineering techniques. However, this is not economically viable for low volume fabrication. The most promising low-volume technique here electron beam lithography (EBL). However, on insulating substrates, (e.g. for III-V devices), charging during EBL leads to pattern distortion and resolution is limited. Whilst charge mitigation strategies exist, they introduce process complexity, and resolution limits. A new approach using aconductive triphenylene electron beam resisthas been investigated. Triphenylenes form well-ordered hexagonal columnar discotic liquid crystals that show fast hole mobility (e.g. 10⁻³ cm²V⁻¹s⁻¹) along columns. The triphenylene based chemically amplified resist investigated here has a conductivity of ~10⁻⁶ S/m at room temperature. It has demonstrated high sensitivity in EBL, requiring a patterning dose of ~14 μC/cm² on silicon and ~10 μC/cm² on fused silica substrates at 50 keV exposure. The resist has demonstrated high-resolution patterning including 20 nm half pitch lines on silicon, and 55 nm isolated lines on glass at 30 keV exposure.
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Sabouri, Aydin. "Nanofabrication by means of focused ion beam." Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/5987/.
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Focused ion beam (FIB) systems have been used widely in micro/nano technology due to their unique capabilities. In this fabrication technique, ions are accelerated towards the sample surfaces and substrate atoms are removed. Despite the ubiquity of this method, several problems remain unsolved and are not fully understood. In this thesis, the effects of FIB machining and its halo effects on substrate are investigated. A novel detector which can perform measurements of the current density profile of the generated beam, was successfully demonstrated. The effect of ion solid interactions for 30keV Ga FIB are investigated through atomic force microscopy (AFM) and Raman spectroscopy, for various machining parameters such as current, dwell time and pixel spacing. The FIB implanted regions were also studied for use as a hard mask in plasma etching, and was found to be suitable for high speed patterning in large area fabrication of nano-featured surfaces for metamaterials. It was observed by controlling the implantation parameters, the ultra-thin structures could be made. These structures have wide range of applications such as nano-scale resonators with application of chemical and biological sensing, membranes with nano-pores for DNA translocation and fabrication of near field optical devices.
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Vicary, James Alexander. "High-speed atomic force microscopy for nanofabrication." Thesis, University of Bristol, 2006. http://hdl.handle.net/1983/b79a500e-8856-470f-a3aa-bde7f531cb0a.
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Moon, Euclid E. (Euclid Eberle) 1965. "Dynamic nanometer alignment for nanofabrication and metrology." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/41799.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (leaves 163-164).
Future generations of IC fabrication depend in part on continued improvements in lithography. To meet the lithographic challenges posed by 25- nm lithography, a novel through-the-mask, interferometric imaging alignment method is described that has demonstrated detectivity below 1 nm. Approximately x-ray alignment and exposure system was constructed which incorporates this "Interferometric Broadband Imaging" (IBBI) alignment scheme. 18BI employs complementary grating and checkerboard-type alignment marks on mask and wafer, respectively. Interference fringes are imaged onto a CCD camera when viewing the marks at a Littrow angle of 15 degrees. Alignment is signified by the spatial phase discontinuities between two identical sets of interference fringes that move in opposite directions as the mask is translated relative to the wafer. The robustness of IBBI was verified by demonstrating that the relative spatial phase is not affected when overlayers of resist, polysilicon, or aluminum cover the alignment marks. Further verification of robustness was found when the illuminating and viewing beams traversed long optical paths through air, glass, and helium. It is significant that JBBJ measurements are made external to a helium enclosure through the above optical paths, since this allows continuous observation of alignment during exposure. Feedback stabilization was developed to nullify the effects of thermal drift and mechanical disturbances during exposure. Over several hours the relative position of the mask and wafer was demonstrated to be locked to within [sigma]=1.4 nm.
by Euclid E. Moon.
S.M.
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Jang, Chang-Hyun. "AFM-Assisted Nanofabrication using Self-Assembled Monolayers." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/11103.
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This study describes the covalent and the electrostatic attachment of molecules, nano-particles, and proteins to patterned self-assembled monolayers. A scanning probe nanografting technique was employed to produce patterns of various sizes, down to 10 nm. Thus, we are able to demonstrate a degree of surface patterning which is an order of magnitude smaller than that used in the semiconductor industry.
One efficient strategy for creating chemically specific nanostructures is to use the extraordinary catalytic properties of enzymes. However, as the dimension of a catalyst patch is reduced down to nanometer scale, it is difficult to detect the very low concentration of product. This study resolves the problem by developing a new strategy: the surface trapping of a product generated by a nanometer-scale patch of surface-bound enzyme.
An array of proteins finds use when the array contains a number of different proteins. Toward this end, a new and convenient method for immobilizing enzymes is developed, which will allow the preparation of thin films containing several different catalytically-active enzymes on the nanoscale.
The disadvantage of scanning probe nanografting technique is that the AFM tip loses resolution through wear during the patterning procedure. This study examines the possibility of developing a new AFM lithographic method to avoid wear: the use of enzymes covalently attached to a tip as a site-specific catalyst.Ph. D.
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Mirza, Muhammad M. "Nanofabrication of silicon nanowires and nanoelectronic transistors." Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/6495/.
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This project developed a robust and reliable process to pattern < 5 nm features in negative tone Hydrogen silsesquioxane (HSQ) resist using high resolution electron beam lithography and developed a low damage reactive ion etch (RIE) process to fabricate silicon nanowires on degenerately doped n-type silicon-on-insulator (SOI) substrates. A process to thermally grow high quality silicon dioxide (SiO2) (between 5-15 nm) is also developed to passivate onto the etched silicon nanowire devices to serve the purposes of gate dielectric and a diffusion barrier to minimize the donor deactivation. The measured interface state trap density (Dit) of the 10 nm thermally grown oxide is 1.3x10^10 cm^−2 eV^−1 with a breakdown voltage of ~7 V. Using optimized processes for lithography, dry etch and thermal oxidation, Hall bar and Greek cross devices are fabricated with mean widths from 45 to 4 nm on SOI substrates with a doping density ~ 2x10^19, 4x10^19, 8x10^19 and 2x10^20 atoms/cm^3 and electronically characterized at room and cryogenic temperatures (from 1.4 to 300 K) to allow resistivity, mobility and carrier density to be extracted directly as a function of temperature. This allowed to probe electron transport and scattering mechanisms in degenerately doped silicon nanowires. The mean free path is theoretically calculated and directly compared with the widths of the nanowires by which it can be approximated that the electron transport is 3 dimensional (3D) for the 12 nm wide nanowire which has likely to be changed to 2D and 1D for the 7 nm and 4 nm wide nanowires respectively. Moreover the experimental mobility is directly compared with a number of theoretically calculated mobilities using Matthiessen’s rule, where it has been determined that the neutral impurity scattering is the dominant scattering mechanism limiting the performance of silicon nanowires. Using silicon nanowires, junctionless transistors are fabricated on SOI substrate with a doping density ~ 4x10^19 atoms/cm^3 and electronically characterized at room and cryogenic temperatures (from 1.4 to 300 K). It was observed that reducing the width of channel from 24 to 8 nm, the transistor changed their operation from depletion to enhancement mode due to increase in the surface depletion at smaller length scales. Since the drain current in a junctionless transistor is proportional to the doping density, a high on-state drive current ~ 1.28 mA/µm has been observed with sub-threshold slope (SS) ~ 66 mV/decade at 300 K. Moreover temperature dependent measurements revealed a low SS ~ 39 mV/decade at 70 K and single electron oscillations at 1.4 K. Finally, independent arrays of 2 terminal nanowires devices with mean widths from 45 to 4 nm are fabricated on SOI substrate with a doping density ~ 8x10^19 atoms/cm^3 to detect polyoxometalate (POM) molecules [W18O54(SeO3)2]4−. A change in resistivity has been observed ~ 3.6 m ohm-cm (corresponds to ~ 13 % increase) when POM molecules are coated around the nanowires, shown n-type behaviour of molecules. POM molecules exhibit highly redox properties, therefore side-gated FETs with mean width ~ 4 nm were fabricated on SOI substrate with a doping density ~ 4x10^19 atoms/cm^3 where side-gate was used to apply alternative ± pulses of 20 V to charge and discharge the POM molecules to demonstrate flash memory operation. The average change in the threshold voltage was ~ 1.2 V between the charging (program) and the discharging (erase) cycles. The program/erase time is currently limited to 100 ms for a reasonable single-to-noise ratio. Moreover no significant decay in the stored charge has yet been measured over a period of 2 weeks (336 hours).
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Yurchenko, Konstantin J. "Investigation of atmospheric microplasma jet for nanofabrication /." Online version of thesis, 2009. http://hdl.handle.net/1850/10627.
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CICERONI, CLAUDIO. "Nanomaterials and nanofabrication for next generation photovoltaics." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2014. http://hdl.handle.net/2108/203102.
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On December 2015, almost 200 countries were represented in Paris, discussing on the topics of climate change and Kyoto Protocol. According to the organizing committee at the outset of the talks, the expected key result was an agreement to set a goal of limiting global warming to less than 2°C compared to pre-industrial levels [1]. In order to reach this goal, huge cut on polluted emissions has to be done, finding new resources to produce energy. Photovoltaics is a sustainable and environmentally clean energy source that has the potential to become one of the main ones, in the near future. In order for this to happen, photovoltaics needs to be economically competitive with other conventional energy sources: despite the price of conventional Si solar cells dropped from ~4 USD/WP to ~0.54 USD/WP in the last 15 years [2], the use of new materials to get even more low-cost solar cells created the field of the so-called “new generation photovoltaics”.
Organic (polymeric and small molecules) solar cells have been extensively investigated, in the last years, not only for the potential low fabrication costs, but also for the possibility of building integration and for the solution process realization that allows spray, Roll-toroll and printing techniques, over rigid or flexible substrates. Moreover, perovskite solar cells, that are also compatible with the above mentioned production methods, recently outperformed multicrystalline Si, showing an impressive certified efficiency of 22.1 % [3]. This “new gen” solar cells strictly rely on research performed in the nanometric world: the typical thickness of an active layer for organic solar cell is hundreds of nanometers; phase separation between different components of polymeric solutions are investigated by the mean of Atomic Force Microscopy, which allows to see features in the order of some nanometers; perovskite is likely deposited on top of scaffold with nanometric pores. So, integrate nanomaterials and nanofabrication steps in the realization of such solar cells is of great interest.
In this work, the possible interactions of nanomaterials as Carbon Nanotubes (CNTs) and Nanoporous Alumina, as well as the integration of nanotechnology process such as
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Nanoimprint Lithography, have been investigated in the field of new gen solar cells. A thorough research on Carbon nanotubes (CNTs) has been carried out to realize semitransparent electrodes to be used as contacts in an organic solar cell. A “two temperature zone” Chemical Vapour Deposition (CVD) set-up is assembled to synthesize CNTs directly on top of Fluorine Doped Tin Oxide and standard glass. The transparency of the asprepared contacts is increased by the mean of a laser patterning technique. An additional technique used to deposit a very thin layer of Nickel, to enhance the conductivity of such semitransparent electrodes, is also presented.
The necessity of decreasing the roughness of the CNTs based electrodes, in order to prevent short circuits in organic solar cells, leads to the development of a spray deposition technique of nanotubes solutions on top of glass substrates. The use of different solutions, with and without the addition of surfactants, as well as the upgrade of the spray set-ups and the design of appropriate metal contacts for inverted organic P3HT:PCBM solar cells are shown.
The inverted architecture of bulk heterojunction solar cell is used also in combination with the Nanoimprint Lithography Technique (NILT): the creation of a pattern of nanometers size on the polymer surface, in order to realize a Photonic Crystal effect designed by optical simulations, is carried out through several technology obstacles, for each of which is given a proper solution.
Lastly, scaffolds of ordered Nanoporous Alumina, realized through the anodization of pure and evaporated Aluminium on glass, are used for the growth of perovskite active layers that are characterized by absorbance measurements.
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Conde, Rubio Ana. "Nanofabrication, simulation and optical characterization of plasmonic nanostructures." Doctoral thesis, Universitat de Barcelona, 2018. http://hdl.handle.net/10803/663481.
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This thesis is devoted to the nanofabrication, simulation and optical characterization of different plasmonic nanostructures.
When an electromagnetic wave reaches a metallic nanostructure, it can give rise to collective oscillations of the free electrons in the metal. These oscillations reach a maximum at the so-called surface plasmon resonance, whose intensity and frequency depend in the material, geometry, embedding medium, interparticle interactions, etc.
Based on the tunability of core-shell nanoparticles, hollow cylindrical gold nanostructures (nanocups) have been fabricating using a combination of nanoimprint lithography (NIL) and non-directional metallization. Besides, to overcome the high-aspect ratio limitations of NIL, a trilayer stack (resist-oxideresist) has been used in such a way that the bottom resist layer, which controls the height of the nanostructure, is not affected by the lithography, which takes place only in the top resist layer. Also, the fabrication method allows for easy changes in the geometry: the height can be changed by changing the thickness of the bottom resist layer, the thickness by modifying the amount of deposited material and the diameter by changing the etching time. By hanging the geometric parameters of the nanostructures, the plasmonic properties can be easily tuned. Besides, for certain dimensions (400 nm in diameter and height and 30 nm of Wall and base thickness), these structures present a peak in the extinction spectra in the visible range that corresponds to a concentration of the electric field within the cavity. This excitation mode has also been reported for other nanostructures with semispherical symmetry. However, the fact of being cylindrical enables a homogeneous enhancement of the electric field along the cavity while in the other case this is not possible due to the lack of symmetry.
Also, based on geometrically frustrated magnetic systems, three particular cases of hexagonal lattices of plasmonic nanoelements have been studied. All of them have been designed so that the pitch is of the order of the resonance wavelength and the gaps between elements small enough to enable near-field coupling. Besides, a metal-insulator-metal configuration has been implemented, designed to have constructive interference, which leads to high absorption peaks.
The samples have been fabricated by electron beam lithography to be able to change easily the design and study the optical response as a function of the geometries. Both simulation and spectroscopy results show that all these systems present high absorption peaks in the visible and/or near infrared. Also, they present a broad absorption peak in the NIR due to the dipolar excitation of the gaps between neighboring elements and sharper peaks in the visible that are assigned to collective modes. Moreover, these systems present an extended time response where the system fluctuates between collective and localized modes. This behavior, characteristic from magnetic frustrated systems, is induced by the frustration of the dipolar excitation of the gaps due to the geometry of the lattice. Besides, the collective modes give rise to enhancements of the electric field in large areas, making these systems of interest for enhanced spectroscopies.Esta tesis está dedicada a la nanofabricación, simulación y caracterización de las propiedades ópticas de diferentes nanoestructuras de oro. Por un lado, inspirados por las nanopartículas tipo core-shell, se han fabricado nanoestructuras de oro cilíndricas en forma de taza, combinando litografía por nanoimpresión (NIL) con metalización por pulverización catódica. Para tener la posibilidad de fabricar estructuras de una elevada altura frente a su anchura, se ha utilizado una tricapa de resina-óxido-resina, de manera que la capa inferior de resina controla la altura de las estructuras mientras que la litografía se realiza en la capa superior y por tanto se sobreponen las típicas dificultades que aparecen en NIL para estructuras de elevada relación de aspecto. Estas nanoestructuras, al igual que las nanoparticulas core-shell, presentan tambien gran capacidad de ajuste de sus propiedades como función de su geometria. Por otro lado, basados en los sistemas magnéticos con frustración geometrica, se han estudiado diferentes redes hexagonales de nanoelementos de oro. Todos los sistemas se han diseñado de modo que el periodo es del orden de la longitud de onda de resonancia y los espacios entre estructuras suficientemente pequeños para tener acoplo de campo cercano. Se ha utilizado una configuración metal-aislantemetal para obtener interferencia constructiva y, en consecuencia, picos de alta absorción. Las muestras se han fabricado utilizando litografía por haces de electrones para poder estudiar los cambios en la respuesta óptica en función de la geometría. Estos sistemas presentan un pico de absorción ancho en el infrarrojo ligado a la excitación dipolar de los huecos entre nanoestructuras y picos más estrechos en el visible que corresponden a modos donde predomina el comportamiento colectivo del sistema. Además, el estudio de la evolución temporal del sistema muestra que este tipo de redes presentan una respuesta extendida en el tiempo inducida por la frustración geométrica del sistema, característica de los sistemas magnéticos frustrados, durante la cual el sistema oscila entre modos localizados y modos colectivos. Por todo ello, consideramos que estas estructuras pueden ser de interés para aplicaciones relacionadas con la absorción de luz.
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Kostovski, Gorgi, and gorgi kostovski@rmit edu au. "Photolithographic and Replication Techniques for Nanofabrication and Photonics." RMIT University. Electrical and Computer Engineering, 2008. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20081203.161726.
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In the pursuit of economical and rapid fabrication solutions on the micro and nano scale, polymer replication has proven itself to be a formidable technique, which despite zealous development by the research community, remains full of promise. This thesis explores the potential of elastomers in what is a distinctly multidisciplinary field. The focus is on developing innovative fabrication solutions for planar photonic devices and for nanoscale devices in general. Innovations are derived from treatments of master structures, imprintable substrates and device applications. Major contributions made by this work include fully replicated planar integrated optical devices, nanoscale applications for photolithographic standing wave corrugations (SWC), and a biologically templated, optical fiber based, surface-enhanced Raman scattering (SERS) sensor. The planar devices take the form of dielectric rib waveguides which for the first time, have been integrated with long-period gratings by replication. The heretofore unemployed SWC is used to demonstrate two innovations. The first is a novel demonstration of elastomeric sidewall photolithographic mask, which exploits the capacity of elastomers to cast undercut structures. The second demonstrates that the corrugations themselves in the absence of elastomers, can be employed as shadow masks in a directional flux to produce vertical stacks of straight lines and circles of nanowires and nanoribbons. The thesis then closes by conceptually combining the preceding demonstrations of waveguides and nanostructures. An optical fiber endface is em ployed for the first time as a substrate for patterning by replication, wherein the pattern is a nanostructure derived from a biological template. This replicated nanostructure is used to impart a SERS capability to the optical fiber, demonstrating an ultra-sensitive, integrated photonic device realized at great economy of both time and money, with very real potential for mass fabrication.
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Jones, Alexandra Gemma. "Nanofabrication of Semiconductor Materials by Novel Nanolithographic Techniques." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.509046.
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Zhang, Yang. "CMOS-MEMS Probe Arrays for Tip-Based Nanofabrication." Research Showcase @ CMU, 2014. http://repository.cmu.edu/dissertations/451.
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Scanning probe microscopy (SPM) tip-based nanofabrication (TBN) is a technique that directly creates a variety of nanostructures on a substrate using the nanoscale probe tips. SPM TBN possesses superior resolution and flexibility: nanostructures with feature size under 5 nm have been achieved via SPM TBN, which is beyond what the state-of-the art optical-based lithography technique can provide. However, the inherent serial nature of SPM TBN makes it a low throughput process. Multi-probe SPM systems have therefore been developed to increase the nanofabrication efficiency. Atomic force microscopy (AFM) and scanning tunneling microscopy (STM) are two most commonly used SPM TBN techniques. Most of prior work has focused on contact-mode AFM-based TBN. This work, using CMOS MEMS technology as the design and fabrication platform, develops an active conductive probe array that aims to perform parallel surface imaging and nanofabrication in non-contact STM mode. The CMOS-MEMS process provides a monolithic integration of MEMS devices with CMOS electronics that can facilitate future automation and parallel probe operation. The CMOS-MEMS probe adopts a micro-cantilever structure and applies bimorph electrothermal actuation to control the vertical displacement of the probe tips. The cantilever is designed to be stiff, with a spring constant of 36 N/m that is larger than the force gradient of the cantilever tip-sample interaction forces in the working distance regime of STM in order to avoid the tip-to-sample “snap-in” and ensure the stability of the STM feedback system. A modified Spindt tip process, compatible with post-CMOS MEMS processing, is developed to batch fabricate Ni/Pt composite tips on CMOS-MEMS probe arrays that are used as STM end-effectors. The integrated Ni/Pt tips on the MEMS probes have a tip radius down to 50 vii nm. The Spindt tip demonstrates the capability of both imaging and nanowire fabrication in STM mode. A hierarchical dual-servo STM system is constructed for the parallel STM imaging using two CMOS-MEMS probes. The system consists of a piezoelectric actuator-driven servo and an electrothermal actuator-driven servo to control the vertical displacement of two probe tips and maintain a constant current between the tips and the sample. Both servos use a proportionalintegral controller. The dual-servo STM system is capable of parallel STM image acquisition using CMOS MEMS probe arrays. An on-chip electrothermal proximity sensor pair and probes with embedded microgoniometers are designed to assist the alignment between the CMOS-MEMS probe array and the examined sample surface. The electrothermal proximity sensor pair is used to measure the separation and the non-parallelism between the probe chip and the sample. The electrothermal proximity sensor has a positioning accuracy of around 1 μm. An electrothermal microgoniometer platform is developed to hold a one-dimensional array of active CMOS-MEMS probes and serves to provide the in situ fine adjustment of relative height among these probes. The micro-goniometer has a maximum tilt of 1.2°, which is sufficient to compensate the probe chip-sample misalignment and the possible height difference among array probes introduced by process variations.
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Cheong, Lin Lee. "Novel advancements in nanofabrication for photonic crystal applications." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/84884.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 169-174).
The progress of large-area 2D- and 3D-photonic crystals (PCs) at optical and near infra-red frequencies has been limited by fabrication challenges. Periodic nanostructures must be patterned in high-index and crystalline material such as silicon over large areas (mm² to cm²) with reasonable throughput. These patterns also must be placed coherently over the entire area, and contain controlled defects. No single conventional nanoscale patterning technique is able to fulfil all of these requirements simultaneously. Pattern placement and throughput challenges for planar lithography can be addressed by combining spatial-phase-locked electron-beam lithography (SPLEBL) with lowenergy (sub-2keV) electrons. SPLEBL obtains feedback on the electron-beam position using a reference grid placed on top of the resist. Combining low-energy lithography with SPLEBL places strict requirements on the SPLEBL reference grid. A systematic investigation on a suitable grid material is carried out, and a self-assembled monolayers (SAMs) based grid is fabricated and characterized. Another method of fabricating large area planar PCs is through interference lithography (IL). The key challenge is the inability of IL to pattern defects or non-periodic structures and thermal scanning probe lithography (TSPL) is proposed as a complementary technique to IL. Integrating TSPL with IL requires capability to transfer TSPL-fabricated patterns into underlying material and is challenging due to the thermal-mechanical nature of TSPL. A robust pattern transfer process is designed and the effects of the lithography and etch processes on resolution and line-edge roughness is studied. The membrane-stacking approach, where large-area membranes are fabricated in parallel and then stacked to form a 3D-PC, was proposed as a more efficient method of fabricating 3D-photonic crystals (3D-PCs) compared to conventional fabrication methods. There exists a need to develop techniques capable of fabricating, transferring and assembling these membranes. In this thesis, a membrane-on-carrier (MOC) strategy based on the membrane-stacking approach is proposed. Membranes are fabricated and floated on liquid, and then transferred onto a temporary rigid carrier. The key challenge is in separating the membrane from the rigid carrier onto a receiving substrate. A dissolvable separation layer is introduced between the membrane and carrier, and two membranes are stacked on top of another as proof-of-concept. Finally, azimuthal alignment is incorporated into the process.
by Lin Lee Cheong.
Ph.D.
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Kant, Rishi. "Silicon migration as a process for micro/nanofabrication /." May be available electronically:, 2009. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Sun, Chih-Hung. "Development of a scalable bottom-up nanofabrication platform." [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0041083.
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Ishii, Masaru. "Nanofabrication and STM/XPS Studies of Automotive Model Catalysts." Thesis, University of Reading, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485372.
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Scanning Tunnelling Microscopy (STM) and X-ray Photoelectron Spectroscopy (XPS) have been used in this work at various temperatures to study the mechanism of NOx storage reaction using model catalysts based mainly on the li02 (110) and the Pt (111) surfaces. The metals Pd and 8a were deposited using metal vapour deposition (MVD». The key findings of this work are summarised below. Prior to the investigation of the 8a/Pdm02 (110) model catalyst, the NOx reactivity with the clean li02 (110) surface and Sa reactivity with li02 (110) were studied. NO and N02was adsorbed on the clean li02 (110)-(1 X2) surface in the molecule state at room temperature and dissociated 'at 373 K in the XPS. However, the amount of adsorbed NO or N02 was small, - less than 0.1 ML, and there was no evidence of or~ered structure of any reactivity between NO and li02 (110) in the STM. Upon increasing the·annealing temperature, liN was formed at 873 K by reaction of dissociated N with interstitialli3 + diffused from the bulk. On the other hand, for a small amount of 8a deposition on the li02 (110) surface, the surface was disordered, but rows of 8a were seen running in the [001] direction of the li02 substrate. Upon sintering at 1073K in UHV, a (2x2) pattern was seen in LEED that originated from the Sa, although no ordering could be seen with STM. NO and O2were adsorbed on the Pd/Sarn02 (110) model catalysts, which was prepared by the 8a deposition and then Pd deposition at 673 K. However it was less reactive due to a low NO sticking probability and it was impossible to obtain atomic resolution images of model catalysts. A new approach, using inverse catalysts, was adopted, that is, Pt (111) was used as the support and Sa was deposited at room temperature. A locally ordered (2x2) structure was obtained. In the case of the annealing temperature at 1273 K, the variety of structures were formed, which these structures might be Sa overlayer, Sa/Pt alloy and BaO. One of these structures is the banded zig-zag structure on the terrace, with the unit cell can be defined as (8 ~ J. After the introduction of O2 at· 573 K, large scale images of BaO were obtained. The average spacing is - 8.6 A, twice that expected for the (111) plane of BaO, which is due to reconstruction, resulting in the formation of (2x2) structure. There was a metastable state of a top layer of BaO/Pt (111) model catalyst at 573 K in the presence of O2, which is likely to be due to the formation of Ba02 confirmed by the atomic structure of Ba02 in the STM. Upon dosing NO and O2 at 573 K, the BaO particles grew and some growth was confirmed at step edges, especially O2 rich state. This effect is observed by an approximate increase in particle volume of 100%, which is consistent with about half of the oxide being converted to the nitrate. It is therefore postulated that a film of the nitrate effectively encapSUlates the oxide. This surface is unreactive to S02' However, when both S02 and O2 were co-dosed, the , ; atomic structure of BaO has rapidly disappeared which might be converted to the SUlphate, 8aS04, Which would result in poisoning of the real catalyst.
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Marquez, Soto Daniela Trinidad. "Plasmon-Mediated Photothermal Phenomena and Nanofabrication of Applicable Devices." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36002.
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This thesis studies the different ways in which the localized plasmon heating effect of gold nanostructures -activated by plasmon excitation via visible and/or NIR irradiation- can be used to obtain different outcomes following the nanofabrication of applicable devices. Both spatial and temporal control were obtained for each one of the systems developed upon the incorporation of plasmonic gold nanostructures. Spatial control was enabled in hybrid mesoporous drug delivery systems fabricated in this thesis through the localized surface plasmon heating effect that allowed the modification of the dynamics of diffusion of the cargo being delivered, thus giving rise to different rates of release that can be controlled by plasmon excitation. At the same time, the plasmon heating effect proved to be capable of controlling the start of the release by dismantling thermo-responsive gates previously incorporated, thus enabling also a wavelength-controlled feature that enhances the versatility of these systems. Spatial control was also conferred to the photo-patterning applications presented in this dissertation by influencing the degree of motility of gold nanorods (AuNRs) embedded in polymer matrices allowing them to self-assemble when the longitudinal plasmon of the incorporated nanostructures was excited; the patterns generated were quite robust and persisted for extended periods of time. Finally, the feature of spatial heating control was also conferred to catalysis. The Friedel-Crafts alkylation of anisole by benzyl chloride using spherical gold nanoparticles (AuNPs) supported on Nb2O5-based catalysts was performed at bulk temperatures below those necessary for the reaction to occur when using bare or modified Nb2O5; this was the result of the combination of bulk and localized plasmon heating produced -both- via plasmon excitation. This also demonstrates the possibility of using plasmon excitation as an alternative heat source in this type of reactions. By combining the plasmonic properties of metallic nanostructures with those granted by mesoporous materials, polymer matrices and Nb2O5-based materials it was possible to obtain light-activated systems endowed also with temporal control and wavelength control while preserving the original properties of each systems' components. Overall, the content of this thesis describes in detail the practical aspects of combining gold nanostructures with different materials and the rationale behind the development of systems with customized and controllable properties.
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Zin, Melvin T. "Self-assembly and nanofabrication approaches towards photonics and plasmonics /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/15502.
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Burbridge, Daniel John. "Nanofabrication techniques : Novel applications of electron beam induced deposition." Thesis, University of Bath, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.522229.
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In, Hyun Jin. "Origami nanofabrication of three-dimensional electrochemical energy storage devices." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32368.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.Includes bibliographical references (p. 143-154).
The Nanostructured (TM) 3D Fabrication and Assembly Process was developed as a novel method of creating three-dimensional (3D) nanostructured devices using two- dimensional micro- and nanopatterning tools and techniques. The origami method of fabrication is a two-part process in which two-dimensional (2D) membranes are first patterned and then folded into the desired 3D configuration. This thesis presents an origami fabrication method based on the use of SU-8 membranes and elastic gold hinges. Magnetic actuation, stress-induced folding, vertical spacing, and lateral alignment of the membranes are discussed. This thesis also reports on the used of the Nanostructured OrigamiTM process to create a functional electrochemical energy storage device. An electrochemical capacitor, or a supercapacitor, is selected because its performance can be readily improved by the addition of 3D geometry and nanoarchitecture. In addition to improved performance, the origami fabrication method allows such devices to be integrated into preexisting MEMS and IC processes, thus enabling the fabrication of complete micro- and nanosystems with an integrated power supply. The supercapacitors were created by selectively depositing carbon-based electrode materials on the SU-8 membrane and then folding the structure so that oppositely-charged electrode regions face each other in a 3D arrangement. The fabrication process, electrochemical testing procedure, and analysis of the results are presented.
by Hyun Jin In.
S.M.
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Jung, Yeon Sik. "Templated self-assembly of siloxane block copolymers for nanofabrication." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/52791.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references.
Monolayer patterns of block copolymer (BCP) microdomains have been pursued for applications in below sub-30 nm nanolithography. BCP selfassembly processing is scalable and low cost, and is well-suited for integration with existing semiconductor fabrication techniques. The two critical issues are how to obtain reliable long-range ordering of features with minimum defect densities and how to successfully transfer the patterns into other functional materials. Exceptionally well-ordered and robust nanoscale patterns can be made from poly(styrene-b-dimethylsiloxane) (PS-PDMS) BCPs, which have a very large Flory-Huggins interaction parameter between the blocks compared to other commonly used BCPs. Cylinder- or sphere-forming BCP films were spincoated over silicon substrates patterned with shallow steps using optical lithography or nanoscale posts made by electron-beam lithography, and solvent-annealed to induce ordering. This generates patterns with a correlation length of at least several micrometers. The annealed film was treated with plasma to obtain oxidized PDMS patterns with a lateral dimension of 14 - 18 nm. These can be used as an etch mask or an easily removable template for patterning functional materials. Solvent vapor treatments can tune the pattern dimension and morphology. Different degrees of solvent uptake in BCP films during solvent-annealing can manipulate the interfacial interaction between the two blocks, and a mixed solvent vapor can change the effective volume fraction of each block. The self-assembled patterns can be transferred into various kinds of functional materials.
(cont.) For example, arrays of parallel lines were used as a mask to pattern poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) conducting polymer thin films. The resulting PEDOT:PSS nanowire array was used as an chemiresistive-type ethanol-sensing device. Metallic films such as Ti, Pt, Ta, W, and magnetic Co and Ni were structured using a pattern-reversal process. Coercivity enhancements were observed for the fabricated ferromagnetic nanostructures such as wires, rings, and antidots. These functional nanostructures can be utilized for a variety of devices such as high-density and high performance sensor or memory devices.
by Yeon Sik Jung.
Ph.D.
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Barwicz, Tymon. "Accurate nanofabrication techniques for high-index-contrast microphotonic devices." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33169.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2005.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 195-199).
High-refractive-index-contrast microphotonic devices provide strong light confinement allowing for sharp waveguide bends and small dielectric optical resonators. They allow dense optical integration and unique applications to optical filters and sensors but present exceptional complications in design and fabrication. In this work, nanofabrication techniques are developed to address the two main challenges in fabrication of high-index contrast microphotonic devices: sidewall roughness and dimensional accuracy. The work focuses on fabrication of optical add-drop filters based on high-index contrast microring-resonators. The fabrication is based on direct-write scanning-electronbeam lithography. A sidewall-roughness characterization and optimization scheme is developed as is the first three-dimensional analysis of scattering losses due to sidewall roughness. Writing strategy in scanning-electron-beam lithography and absolute and relative dimensional control are addressed. The nanofabrication techniques developed allowed fabrication of the most advanced microring add-drop-filters reported in the literature. The sidewall-roughness standard deviation was reduced to 1.6 nm.
(cont.) The field polarization and the waveguide cross-sections minimizing scattering losses are presented. An absolute dimensional control accuracy of 5 nm is demonstrated. Microring resonators with average ring-waveguide widths matched to 26 pm to a desired relative width-offset are reported.
by Tymon Barwicz.
Ph.D.
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Habibi, Sina. "Ultraprecise nanofabrication with extremely low dose focused ion beams." Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648795.
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Alalwan, Hasanain Kahtan Abdulkhalik. "Combining nanofabrication with natural antimicrobials to control denture plaque." Thesis, University of Glasgow, 2018. http://theses.gla.ac.uk/30751/.
Full textAbstract:
Management of fungal biofilms represents a significant challenge to oral healthcare. As a preventive approach, minimising adhesion between intra-oral devices and microorganisms would be an important step forward. Denture stomatitis (DS) is a multifactorial denture-associated inflammation of the oral mucosa where candidal biofilms are one of the contributing factors. Therefore, understanding candidal biofilms on dentures and finding novel strategies to control these biofilms are of significance. Interference with the adhesion step of biofilm formation is hypothetically effective strategy to control biofilms. To understand the relationship between denture candidal load, denture material type and C. albicans biofilm forming heterogeneity in DS, quantitative polymerase chain reaction (qPCR) molecular method and crystal violet (CV) assay were used. This study investigated two novel strategies to control C. albicans biofilms through interfering with adhesion: natural polyphenol curcumin (CUR) and modifying the topography of the denture material surface. Based on the optimised effective CUR concentrations, CUR adsorption to PMMA denture material was spectrophotometrically analysed. Based on these data, the effect of adsorbed CUR to PMMA and CUR pre-exposure on adhesion of C. albicans were assessed. The effect of CUR on Candida-Candida adhesion was investigated and the expression profile of selected adhesion and aggregation-associated genes was assessed using qPCR method. Micro/nano-fabricated polycarbonate and PMMA materials were replicated using injection and compression moulding techniques, respectively and were characterised using scanning electron microscopy (SEM). Adhesion of C. albicans on the micro and nano-scaled patterns was assessed using microscopic and qPCR molecular methods, respectively. The physical characteristics of the materials were assessed using theta tensiometer and a white light profiler. The data demonstrated that although C. albicans was detected in greater quantities in diseased individuals, it was not associated with increased biofilm biomass. Denture substrata were shown to influence biofilm biomass, with poly(methyl methacrylate) providing the most suitable environment for C. albicans to reside. Subsequent studies showed that CUR concentrations of 50 μg/ml could prevent adhesion to PMMA. This effect was enhanced by the CUR pre-treatment of yeast cells (>90% inhibition, p < 0.001). Investigation of the biological impact of CUR showed that it preferentially affected immature morphological forms (yeast and germlings), and actively promoted aggregation of the cells. Transcriptional analyses showed that CUR temporally modulated adhesion and aggregation associated genes. Finally, PMMA denture material was replicated to show nano features. These topographies influenced adhesion of C. albicans, depending on the candidal morphological form and the shape. Nano-pit spatial arrangements variably affect the adhesion of C. albicans, where SQ arrangement demonstrated a significant anti-adhesive capacity. Differential adhesin expression was observed on these surfaces, which were affected by the wettability and roughness of surfaces tested. In summary, C. albicans is an important determinant of denture disease, so preventing its adhesion and biofilm formation were worthwhile objectives. This thesis has shown that CUR molecules and SQ nano-pit topographies reduced C. albicans adhesion, demonstrating that chemical and physical inhibition strategies are useful. The data presented in this thesis showed the high potential of the novel strategies to be used against C. albicans biofilms, and encourages the further investigation of these approaches against polymicrobial denture biofilms.
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Rajagopal, Senthil Arun. "SINGLE MOLECULE ELECTRONICS AND NANOFABRICATION OF MOLECULAR ELECTRONIC DEVICES." Miami University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=miami1155330219.
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Quidant, Romain. "Dispositifs optiques submicroniques : nanofabrication et caractérisation en champ proche." Dijon, 2002. http://www.theses.fr/2002DIJOS026.
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Spinney, Patrick S. "Nanofabrication and Testing of an Instrumented Nanopore for DNA Sensing." Fogler Library, University of Maine, 2011. http://www.library.umaine.edu/theses/pdf/SpinneyP2011.pdf.
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Holzwarth, Charles W. III (Charles Willett). "Material selection and nanofabrication techniques for electronic photonic integrated circuits." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/53248.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2009.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 149-154).
Electronic-photonic integrated circuits have the potential to circumvent many of the performance bottlenecks of electronics. To achieve the full benefits of integrating photonics with electronics it is generally believed that wavelength-division multiplexing is needed; requiring an integrated optical device capable of multiplexing/demultiplexing operations. One such device is a bank of microring-resonator filters with precisely spaced resonant frequencies. In this work, a fabrication strategy based on scanning-electron-beam lithography (SEBL) is presented for precisely controlling the resonant frequency of microring-resonator filters. Using this strategy it is possible to achieve dimensional control, on the tens-of- picometer scale, as required for microring-resonator filter banks. To correct for resonant-frequency errors present after fabrication, two forms of postfabrication tuning, one dynamic and one static, are demonstrated. It is also shown that hydrogen silsesquioxane (HSQ) can be converted into a high-quality overcladding for photonic devices by optimizing the annealing process. Finally, a postfabrication technique of localized substrate removal is presented, enabling the integration of photonics with CMOS electronics. Second-order microring-resonator filter banks were fabricated using SiNx and Si as the high -index core materials. By controlling the electron-beam-exposure dose it is possible to change the average microring-waveguide width to a precision better than 75 pm, despite the 6 nm SEBL address grid. Using postfabrication tuning the remaining resonant-frequency errors can be reduced to less than 1 GHz.
(cont.) By annealing HSQ in a an 02 atmosphere using rapid thermal processing, it is possible to create thick overcladding layers that have essentially the same optical properties as SiO2 with the excellent gap-filling and planarization properties of HSQ. Using XeF2 to locally etch an underlying Si substrate, waveguides with a propagation loss of -10 dB/cm were fabricated out of polysilicon deposited on 50 nm of SiO2.
by Charles W. Holzwarth, Ill.
Ph.D.
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Bruinink, C. M. "Pattern strategies in nanofabrication from periodic patterns to functional nanostructures /." Enschede : University of Twente [Host], 2009. http://doc.utwente.nl/60764.
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Guerfi, Youssouf. "Réalisation et caractérisation de transistors MOS à base de nanofils verticaux en silicium." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30253/document.
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Afin de poursuivre la réduction d'échelle des transistors MOS, l'industrie des semiconducteurs a su anticiper les limitations de la miniaturisation par l'introduction de nouveaux matériaux ou de nouvelles architectures. L'avènement des structures à triples grilles (FinFET) a permis de maitriser les effets canaux courts et poursuivre les efforts de miniaturisation (nœud technologique 14 nm en 2014). Le cas ultime pour le contrôle électrostatique de la grille sur le canal est donné par une grille entourant totalement le canal du dispositif. A cet effet, un transistor à nanofil à grille entourante est considéré comme la structure la plus adaptée pour les nœuds technologiques en dessous de 7 nm. Au cours de cette thèse, un procédé de réalisation large échelle de transistors MOSFET miniaturisés à base de nanofils verticaux en silicium a été développé. Tout d'abord, les nanofils verticaux ont été réalisés par une approche descendante via le transfert par gravure d'un masque de résine en Hydrogène Silsesquioxane (HSQ), réalisé par lithographie électronique à basse tension d'accélération. Une stratégie de dessin inédite dite "en étoile " a été développée pour définir des nanofils parfaitement circulaires. Les nanofils en Si sont obtenus par gravure plasma puis amincis par oxydation humide sacrificielle. Ce procédé permet d'obtenir des nanofils verticaux en Si avec des parois parfaitement anisotropes, une parfaite reproductibilité et un rendement maximal. L'implémentation des MOSFETs sur les réseaux nanofils a été effectuée par l'ingénierie successive de couches minces nanométriques (conductrices et diélectriques). Dans ce cadre, un procédé innovant de réalisation de couches d'isolations en HSQ par gravure chimique contrôlée a démontré une excellente planéité associée à une rugosité de surface inférieure à 2 nm. Enfin, un procédé utilisant la photolithographie UV conventionnelle a été développé pour réaliser le transistor de longueur de grille nanométrique. Ces dispositifs ont démontré d'excellentes performances électriques avec des courants de conduction supérieurs à 600 µA/µm et une excellente maîtrise des effets de canaux courts (pente sous le seuil de 95 mV/dec et DIBL à 25 mV/V) malgré l'extrême miniaturisation de la longueur de grille (15 nm). Enfin, nous présentons une première preuve de concept d'un inverseur CMOS à base de cette technologie à nanofils verticauxIn order to further downscaling of the MOS transistors, the semiconductor industry has anticipated the limitations of miniaturization by the introduction of new materials and new architectures. The advent of triple gate structures (FinFET) allowed mastering the short channel effects and further miniaturization efforts (14 nm technology node in 2014). The ultimate case to the electrostatic control of the gate on the channel is given by a gate completely surrounding the device channel. For this purpose, Gate All Around (GAA) nanowire transistor is considered as the most suitable structure for technology nodes below 7 nm. In this thesis, a large scale process for the realization of miniaturized MOSFETs based on vertical silicon nanowires has been developed. Firstly, the vertical nanowires were made by a top down approach by the transfer by etching of hard mask made of Hydrogen silsesquioxane (HSQ) resist created at low voltage electron beam lithography. An original design strategy called "star" was developed to define perfectly circular nanowires. Si nanowires are obtained by plasma etching then thinned by sacrificial wet oxidation. This method allows obtaining vertical Si nanowires with perfectly anisotropic walls, a perfect reproducibility and a maximum yield. The implementation of the MOSFETs on the nanowire network was done by successive engineering of nanoscale thin films (conductive and dielectric). In this context, an innovative process for producing insulation layers in HSQ by controlled chemical etching showed excellent flatness associated with surface roughness of less than 2 nm. Finally, a method using conventional UV photolithography has been developed to achieve the nanometer gate length transistor. These devices have demonstrated excellent electrical performances with conduction currents superior than 600 µA/µm and excellent control of short channel effects (subthreshold slope of 95 mV/dec and DIBL of 25 mV/V) despite extreme miniaturization of the gate length (15 nm). Finally, we present a first proof of concept of a CMOS inverter based on vertical nanowires technology
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Sunter, Kristen Ann. "Optical Modeling of Superconducting Nanowire Single Photon Detectors." Thesis, Harvard University, 2014. http://nrs.harvard.edu/urn-3:HUL.InstRepos:13106421.
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Superconducting nanowire single photon detectors (SNSPDs) can detect single photons or low levels of infrared light in applications that require high speed and low timing jitter, such as integrated circuit analysis. Most applications also require a high device detection efficiency (DDE), but the DDE of SNSPDs is limited by many factors. A good optical design with an integrated optical cavity and dielectric layers can increase the absorptance of 1550-nm light in the active area to over 90%. Therefore, optical modeling using the transfer matrix method was used to guide the design and fabrication of high-efficiency detectors with a measured DDE of over 70%. In addition, finite element analysis was used to simulate the effect of adding different types of optical antennas to SNSPD designs to increase their active area without compromising their speed, and the fabrication of antennas integrated with nanowires achieved sub-10 nm gaps between features.
Thin films of niobium nitride, the starting material of the SNSPDs, were investigated using several techniques for thin film characterization, including x-ray diffraction, Auger electron spectroscopy and x-ray photoelectron spectroscopy. Optical setups based on reflectometry and transmittometry were built to determine the film thickness more accurately than deposition time for optical modeling and to provide feedback on the deposition conditions. The optical setups are able to provide reproducible and precise thickness measurements to within 0.1 nm.Engineering and Applied Sciences
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Castro, Arias Juan Manuel. "Towards a Plasmonic and Electrochemical Biosensor Integrated in a Microfluidic Platform." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS020/document.
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Au cours de ma thèse, j'ai développé un procédé de fabrication spécifique capable de produire un biocapteur qui combine deux techniques de biodétection différentes, la réponse plasmonique basée sur la résonance de plasmon de surface localisée (LSPR) et la réponse électrochimique. Les méthodes et les résultats qui sont présentés dans ce manuscrit ont été définis pour converger vers un dispositif fluidique unique combinant ces deux approches de détection différentes. Afin de trouver la configuration permettant l'excitation des résonances plasmoniques, la géométrie des nanocavités MIM (métal/isolant/métal) en réseau de lignes interdigitées a été optimisée par des simulations électromagnétiques. La fabrication par nanoimpression douce assistée UV (SoftUV-NIL) a été optimisée et, finalement, la caractérisation optique de ces nanocavités a été comparée avec succès aux simulations théoriques. Parallèlement à la réalisation de ce dispositif nanostructuré, des dispositifs électrochimiques fluidiques plus simples qui intègrent des microélectrodes classiques ont également été développés. L'objectif était d'abord de développer une chimie innovante pour le couple « biotine/streptavidine » et de comprendre ensuite comment les paramètres fluidiques peuvent affecter l'efficacité de capture des biomolécules. Ce manuscrit se termine par une discussion sur le rôle des paramètres fluidiques concernant l’efficacité de la biodétection sur la base de la théorie de SquiresDuring my thesis, I worked on the development of a specific fabrication process able to produce a device that combines two different biodetection techniques, plasmonic response based on Localized Surface Plasmon Resonance (LSPR) and electrochemical response. Methods and results that are presented in this manuscript were defined to converge towards a unique fluidic device combining these two different sensing approaches. This device integrates interdigitated array of MIM nanocavities. In order to find the easier working configuration allowing the excitation of plasmonic resonances, their geometry has been optimized through electromagnetic simulations. The fabrication of these dual devices has been optimized based on Soft-UV NIL and, finally, optical characterization of these nanocavities has been successfully compared with theoretical simulations. In parallel to this challenging goal, simpler fluidic electrochemical devices that integrate conventional microelectrodes have also been developed. The goal was first to develop an innovative chemistry for the couple biotin/streptavidin and secondly to learn how fluidic parameters can affect the capture efficiency of molecules. This manuscript ends with a discussion on the role of the fluidic parameters on the biodetection efficiency based on the theory of Squires
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Hadjikhani, Ali. "Nanofabrication and Spectroscopy of Magnetic Nanostructures Using a Focused Ion Beam." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2536.
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This research used a focused ion beam in order to fabricate record small nano-magnetic structures, investigate the properties of magnetic materials in the rarely studied range of nanometer size, and exploit their extraordinary characteristics in medicine and nano-electronics. This study consists of two parts: (i) Fabrication and study of record small magnetic tunnel junctions (ii) Introduction of a novel method for detection of magnetoelectric nanoparticles (MENs) in the tissue.
A key challenge in further scaling of CMOS devices is being able to perform non-volatile logic with near zero power consumption. Sub-10-nm nanomagnetic spin transfer torque (STT) magnetic tunneling junctions (MTJs) have the potential for a universal memory that can address this key challenge. The main problem is to decrease the switching current density. This research studied these structures in sub-10-nm size range. In this range, spin related excitations consume considerably smaller amounts of energy as compared to the larger scale. This research concluded that as predicted a decrease in switching current superior to that of the linear scaling will happen in this size range.
Magneto-electric nanoparticles (MENs) can be used to directly couple intrinsic electric-field-driven processes with external magnetic fields for controlling neural activity deep in the brain. These particles have been proven to be capable of inducing deep brain stimulation non-invasively. Furthermore, these magneto-electric nano-particles can be used for targeted drug delivery and are contenders to replace conventional chemotherapy. The circulatory system can deliver a drug to almost every cell in the body; however, delivering the drug specifically into the tumor cell and then releasing it on demand remains a formidable task. Nanomedicine can accomplish this, but ensuring that the drug is released at an appropriate rate once at the target site is an important task. In order to have a complete understanding of the behavior of these MENs when injected into the body, a comprehensive bio-distribution study was performed. This study introduced a novel spectroscopy method for tracing the nanoparticles in the bloodstream. This study investigated the post injection distribution of the MENs in vital organs throughout a period of two months.
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Crespo, Biel Olga. "Nanofabrication of two- and three-dimensional structures by multivalent supramolecular interactions." Enschede : University of Twente [Host], 2006. http://doc.utwente.nl/55441.
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Holmberg, Anders. "Nanofabrication of Zone Plate Optics for Compact Soft X-Ray Microscopy." Doctoral thesis, Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4045.
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Hildreth, Owen James. "Development of metal-assisted chemical etching as a 3D nanofabrication platform." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/49011.
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The considerable interest in nanomaterials and nanotechnology over the last decade is attributed to Industry's desire for lower cost, more sophisticated devices and the opportunity that nanotechnology presents for scientists to explore the fundamental properties of nature at near atomic levels. In pursuit of these goals, researchers around the world have worked to both perfect existing technologies and also develop new nano-fabrication methods; however, no technique exists that is capable of producing complex, 2D and 3D nano-sized features of arbitrary shape, with smooth walls, and at low cost. This in part is due to two important limitations of current nanofabrication methods. First, 3D geometry is difficult if not impossible to fabricate, often requiring multiple lithography steps that are both expensive and do not scale well to industrial level fabrication requirements. Second, as feature sizes shrink into the nano-domain, it becomes increasingly difficult to accurately maintain those features over large depths and heights. The ability to produce these structures affordably and with high precision is critically important to a number of existing and emerging technologies such as metamaterials, nano-fluidics, nano-imprint lithography, and more. Summary To overcome these limitations, this study developed a novel and efficient method to etch complex 2D and 3D geometry in silicon with controllable sub-micron to nano-sized features with aspect ratios in excess of 500:1. This study utilized Metal-assisted Chemical Etching (MaCE) of silicon in conjunction with shape-controlled catalysts to fabricate structures such as 3D cycloids, spirals, sloping channels, and out-of-plane rotational structures. This study focused on taking MaCE from a method to fabricate small pores and silicon nanowires using metal catalyst nanoparticles and discontinuous thin films, to a powerful etching technology that utilizes shaped catalysts to fabricate complex, 3D geometry using a single lithography/etch cycle. The effect of catalyst geometry, etchant composition, and external pinning structures was examined to establish how etching path can be controlled through catalyst shape. The ability to control the rotation angle for out-of-plane rotational structures was established to show a linear dependence on catalyst arm length and an inverse relationship with arm width. A plastic deformation model of these structures established a minimum pressure gradient across the catalyst of 0.4 - 0.6 MPa. To establish the cause of catalyst motion in MaCE, the pressure gradient data was combined with force-displacement curves and results from specialized EBL patterns to show that DVLO encompassed forces are the most likely cause of catalyst motion. Lastly, MaCE fabricated templates were combined with electroless deposition of Pd to demonstrate the bottom-up filling of MaCE with sub-20 nm feature resolution. These structures were also used to establish the relationship between rotation angle of spiraling star-shaped catalysts and their center core diameter. Summary In summary, a new method to fabricate 3D nanostructures by top-down etching and bottom-up filling was established along with control over etching path, rotation angle, and etch depth. Out-of-plane rotational catalysts were designed and a new model for catalyst motion proposed. This research is expected to further the advancement of MaCE as platform for 3D nanofabrication with potential applications in thru-silicon-vias, photonics, nano-imprint lithography, and more.