Thin films and nanowires of Co-Pt have been prepared by means of electrodeposition. Composition, structure, microstructure and magnetic properties have been intensively studied using X-ray diffraction, scanning electron microscopy and vibrating sample magnetometry and correlated to the deposition parameters such as electrolyte composition, deposition current and/or potential. Co rich Co-Pt films have been deposited at various current densities. A nearly constant composition of Co70Pt30 was achieved for current densities between 18 and 32 mA/cm². Detailed texture measurements confirmed an increasing fraction of the hexagonal phase with its c-axis aligned perpendicular to the film plane with increasing current density. Accordingly, magnetic properties are strongly affected by the magnetocrystalline anisotropy of the hexagonal phase that competes with the shape anisotropy of the thin film geometry. Co-Pt nanowires have been prepared within alumina templates at different deposition potentials between -0.6 and -0.9VSCE changing the composition from nearly pure Pt to Co. The composition Co80Pt20 was observed at a deposition potential of -0.7VSCE. Co-Pt nanowires are nanocrystalline in the as-deposited state. Magnetic measurements reveal changing fcc and hcp phase fractions within the wires as the effective anisotropy significantly differs from the expected shape anisotropy for nanowires with high aspect ratio. This change in effective anisotropy is attributed to the preferential alignment of the c-axis of hcp Co-Pt phase perpendicular to the nanowires axis. A promising alternative with much smaller feature sizes is the diblock copolymer template. Electrodeposition of Co and Co-Pt into these templates has been carried out. Inhomogeneities in the template thickness as well as a certain substrate roughness have been identified to be the reasons for inhomogeneous template filling. Thus magnetic properties are dominated by large deposits found on top of the template. Additionally, rolled-up tubes of several nm thick Au/Co/Au films have been characterized magnetically. Temperature dependent measurements show an exchange bias behaviour that is explained in terms of induced stresses during cooling. Changes of magnetic properties in the investigated samples are finally discussed in terms of competing effects of different magnetic anisotropies in various geometries. / Co-Pt Dünnschichten und Nanodrähte wurden mittels elektrochemischer Abscheidung hergestellt. Zusammensetzung, Struktur, Mikrostruktur und magnetische Eigenschaften wurden intensiv mit Röntgenbeugung, Rasterelektronenmikroskopie und Magnetometrie untersucht und mit den Depositionsparametern wie Elektrolytzusammensetzung, Abscheidestrom und/oder-potential korreliert. Co reiche Co-Pt-Filme wurden mit verschiedenen Stromdichten hergestellt. Eine nahezu konstante Zusammensetzung im Bereich Co70Pt30 wurde für Stromdichten zwischen 18 und 32 mA/cm² erreicht. Detaillierte Texturmessungen bestätigen einen zunehmenden Anteil an hexagonaler Phase mit senkrecht zur Filmebene ausgerichteter c-Achse mit zunehmender Stromdichte. Dementsprechend werden die magnetischen Eigenschaften stark von der magnetokristallinen Anisotropie der hexagonalen Phase beeinflusst, die mit der Formanisotropie der Dünnschicht-Geometrie konkurriert. Co-Pt-Nanodrähte wurden in nanoporöse Aluminiumoxidmembranen bei verschiedenen Potentialen zwischen -0,6 und -0.9 VSCE abgeschieden, wobei sich die Zusammensetzung von nahezu reinem Pt zu Co verändert. Die Zusammensetzung Co80Pt20 wurde bei einem Abscheidepotential von -0.7 VSCE erhalten. Die so hergestellten Co-Pt Nanodrähte sind nanokistallin. Magnetische Messungen weisen jedoch auf veränderte Phasenanteile der fcc und hcp Phase innerhalb der Drähte hin, da die effektive Anisotropie erheblich von der für Nanodrähte mit hohem Aspektverhältnis erwarteten Formanisotropie abweicht. Diese Änderung der effektiven Anisotropie ist auf die bevorzugte Ausrichtung der hexagonalen c-Achse des Co-Pt senkrecht zur Drahtachse zurückzuführen. Vielversprechende Template mit deutlich kleineren Dimensionen sind Diblockcopolymertemplate. Es wurden Versuche zur Abscheidung von Co und Co-Pt in diese Template durchgeführt. Als Gründe für die inhomogene Templatfüllung wurden Inhomogenitäten in der Schichtdicke sowie eine gewisse Rauhigkeit der Substrate identifiziert. Aufgrund der ungleichmäßigen Fülleg werden die magnetischen Eigenschaften durch große, halbkugelförmige Abscheidunge auf der Oberfläche des Templates bestimmt. Darüber hinaus wurden aus wenige nm dicken Au/Co/Au Filmen hergestellte Mikroröhren magnetisch charakterisiert. Temperaturabhängige Messungen zeigen ein Exchange Bias Verhalten, das durch beim Abkühlen induzierte Spannungen erklärt wird. Unterschiede im magnetischen Verhalten der untersuchten Proben werden abschließend im Hinblick auf die verschiedenen konkurrierenden magnetischen Anisotropien in verschiedenen Geometrien diskutiert.

Title: Theoretical studies of rolled-up and wrinkled nanomembranes Author: Mgr. Peter Cendula Department: Department of Condensed Matter Physics Thesis Supervisors: Prof. Dr. Oliver G. Schmidt, Prof. RNDr. Václav Holý, CSc. Abstract : The thesis is devoted to three similar topics from the field of rolled-up and wrinkled nanomembranes. We start by recalling classical theory of thin plates, which will be used to describe deformation of nanomembranes. In the first topic, relaxation of internal strain is studied when a flat film is partially released from the substrate by etching the sacrificial layer underneath. Energetic competition of the tube and wrinkle shape is quantitatively investigated. Similar model is used to investigate the limiting maximum value of tube rotations. In the second topic, roll-up of initially wrinkled film is shown to favor tubes forming on the flat edge of rectangular wrinkled pattern, enabling precise control of tube position. Experiment is provided to justify our theoretical predictions. In the third topic, quantum well is assumed inside a wrin- kled nanomembrane. Shift of transition energy induced by lateral modulation due to bending strain is quantified, being of interest for strain-sensitive optical detectors and emitters. In addition, lateral localization of electron and hole due to...

No / A method for measuring the evaporation kinetics of pure solvents and solutions containing Cd3P2 quantum dots (QDs) in SiO/SiO2 rolled-up microtube (RUT) resonators is reported. The QDs serve as wavelength-tunable fluorescent sources for the RUT resonator. The first-order kinetic constant (295 K) of the evaporation of toluene embedded in a RUT (D = 9.10 μm) is evaluated (0.055 min−1). / Doctoral Program Education of China. Grant Number: 20110111120008; Alexander von Humboldt Foundation

Lithium ion batteries (LIBs) have attracted considerable interest due to their wide range of applications, such as portable electronics, electric vehicles (EVs) and aerospace applications. Particularly, the emergence of a variety of nanostructured materials has driven the development of LIBs towards the next generation, which is featured with high specific energy and large power density. Herein, rolled-up nanotechnology is introduced for the design of strain-released materials as anodes of LIBs. Upon this approach, self-rolled nanostructures can be elegantly combined with different functional materials and form a tubular shape by relaxing the intrinsic strain, thus allowing for enhanced tolerance towards stress cracking. In addition, the hollow tube center efficiently facilitates electrolyte mass flow and accommodates volume variation during cycling. In this context, such structures are promising candidates for electrode materials of LIBs to potentially address their intrinsic issues. This work focuses on the development of superior structures of Si and SnO2 for LIBs based on the rolled-up nanotech. Specifically, Si is the most promising substitute for graphite anodes due to its abundance and high theoretical gravimetric capacity. Combined with the C material, a Si/C self-wound nanomembrane structure is firstly realized. Benefiting from a strain-released tubular shape, the bilayer self-rolled structures exhibit an enhanced electrochemical behavior over commercial Si microparticles. Remarkably, this behavior is further improved by introducing a double-sided carbon coating to form a C/Si/C self-rolled structure. With SnO2 as active material, an intriguing sandwich-stacked structure is studied. Furthermore, this novel structure, with a minimized strain energy due to strain release, exposes more active sites for the electrochemical reactions, and also provides additional channels for fast ion diffusion and electron transport. The electrochemical characterization and morphology evolution reveal the excellent cycling performance and stability of such structures.

Thin films and nanowires of Co-Pt have been prepared by means of electrodeposition. Composition, structure, microstructure and magnetic properties have been intensively studied using X-ray diffraction, scanning electron microscopy and vibrating sample magnetometry and correlated to the deposition parameters such as electrolyte composition, deposition current and/or potential. Co rich Co-Pt films have been deposited at various current densities. A nearly constant composition of Co70Pt30 was achieved for current densities between 18 and 32 mA/cm². Detailed texture measurements confirmed an increasing fraction of the hexagonal phase with its c-axis aligned perpendicular to the film plane with increasing current density. Accordingly, magnetic properties are strongly affected by the magnetocrystalline anisotropy of the hexagonal phase that competes with the shape anisotropy of the thin film geometry. Co-Pt nanowires have been prepared within alumina templates at different deposition potentials between -0.6 and -0.9VSCE changing the composition from nearly pure Pt to Co. The composition Co80Pt20 was observed at a deposition potential of -0.7VSCE. Co-Pt nanowires are nanocrystalline in the as-deposited state. Magnetic measurements reveal changing fcc and hcp phase fractions within the wires as the effective anisotropy significantly differs from the expected shape anisotropy for nanowires with high aspect ratio. This change in effective anisotropy is attributed to the preferential alignment of the c-axis of hcp Co-Pt phase perpendicular to the nanowires axis. A promising alternative with much smaller feature sizes is the diblock copolymer template. Electrodeposition of Co and Co-Pt into these templates has been carried out. Inhomogeneities in the template thickness as well as a certain substrate roughness have been identified to be the reasons for inhomogeneous template filling. Thus magnetic properties are dominated by large deposits found on top of the template. Additionally, rolled-up tubes of several nm thick Au/Co/Au films have been characterized magnetically. Temperature dependent measurements show an exchange bias behaviour that is explained in terms of induced stresses during cooling. Changes of magnetic properties in the investigated samples are finally discussed in terms of competing effects of different magnetic anisotropies in various geometries. / Co-Pt Dünnschichten und Nanodrähte wurden mittels elektrochemischer Abscheidung hergestellt. Zusammensetzung, Struktur, Mikrostruktur und magnetische Eigenschaften wurden intensiv mit Röntgenbeugung, Rasterelektronenmikroskopie und Magnetometrie untersucht und mit den Depositionsparametern wie Elektrolytzusammensetzung, Abscheidestrom und/oder-potential korreliert. Co reiche Co-Pt-Filme wurden mit verschiedenen Stromdichten hergestellt. Eine nahezu konstante Zusammensetzung im Bereich Co70Pt30 wurde für Stromdichten zwischen 18 und 32 mA/cm² erreicht. Detaillierte Texturmessungen bestätigen einen zunehmenden Anteil an hexagonaler Phase mit senkrecht zur Filmebene ausgerichteter c-Achse mit zunehmender Stromdichte. Dementsprechend werden die magnetischen Eigenschaften stark von der magnetokristallinen Anisotropie der hexagonalen Phase beeinflusst, die mit der Formanisotropie der Dünnschicht-Geometrie konkurriert. Co-Pt-Nanodrähte wurden in nanoporöse Aluminiumoxidmembranen bei verschiedenen Potentialen zwischen -0,6 und -0.9 VSCE abgeschieden, wobei sich die Zusammensetzung von nahezu reinem Pt zu Co verändert. Die Zusammensetzung Co80Pt20 wurde bei einem Abscheidepotential von -0.7 VSCE erhalten. Die so hergestellten Co-Pt Nanodrähte sind nanokistallin. Magnetische Messungen weisen jedoch auf veränderte Phasenanteile der fcc und hcp Phase innerhalb der Drähte hin, da die effektive Anisotropie erheblich von der für Nanodrähte mit hohem Aspektverhältnis erwarteten Formanisotropie abweicht. Diese Änderung der effektiven Anisotropie ist auf die bevorzugte Ausrichtung der hexagonalen c-Achse des Co-Pt senkrecht zur Drahtachse zurückzuführen. Vielversprechende Template mit deutlich kleineren Dimensionen sind Diblockcopolymertemplate. Es wurden Versuche zur Abscheidung von Co und Co-Pt in diese Template durchgeführt. Als Gründe für die inhomogene Templatfüllung wurden Inhomogenitäten in der Schichtdicke sowie eine gewisse Rauhigkeit der Substrate identifiziert. Aufgrund der ungleichmäßigen Fülleg werden die magnetischen Eigenschaften durch große, halbkugelförmige Abscheidunge auf der Oberfläche des Templates bestimmt. Darüber hinaus wurden aus wenige nm dicken Au/Co/Au Filmen hergestellte Mikroröhren magnetisch charakterisiert. Temperaturabhängige Messungen zeigen ein Exchange Bias Verhalten, das durch beim Abkühlen induzierte Spannungen erklärt wird. Unterschiede im magnetischen Verhalten der untersuchten Proben werden abschließend im Hinblick auf die verschiedenen konkurrierenden magnetischen Anisotropien in verschiedenen Geometrien diskutiert.

The physical limitations of miniaturization of the traditional silicon-based electronic devices have motivated growing interest in molecular electronics due to its promising potential in transcending Moore's Law. Since the concept of molecular rectifier was first proposed by Ratner and Aviram in 1974, a lot of efforts have been devoted to realizing nondestructive electrical contacts to the individual or ensemble molecules, such as liquid metal contact, break junctions, cross wire junctions, etc. Among them, rolled-up nanotechnology is compatible with the conventional photolithography processes and can provide an efficient strategy to fabricate fully integrated functional molecular devices on a chip via an array of damage-free soft contacts. This nanotechnology takes an important step towards implementing the miniaturization of molecular devices and promotes the development of molecular electronics. In this doctoral thesis, rolled-up nanotechnology is employed to develop functional molecular devices on chips. Enabled by these rolled-up soft contacts, fully integrated molecular rectifiers based on ultrathin molecular heterojunctions are developed for the first time, and they are able to convert alternating current to direct current with frequencies up to 10 MHz. This is also the first time that a nanoscale organic rectifier with an operating frequency exceeding 1 MHz has been fabricated. The remarkable unidirectional current behavior of the molecular devices mainly originates from the intrinsically different surfaces of bottom planar and top microtubular gold electrodes. While the excellent high-frequency response is guaranteed by the charge accumulation in the phthalocyanine molecular heterojunction, which not only improves the charge injection but also increases the carrier density. Then this rolled-up nanotechnology is further employed to explore multi-functional molecular devices. In this thesis, fully integrated process-programmable molecular devices are achieved for the first time, which can switch between photomultiplication photodiodes and bipolar memristors. The transition depends on the release of mobile ions initially stored in the bottom polymeric electrode and can be controlled by modulating the local electric field at the interface between the ultrathin molecular layer and the bottom electrode. Photogenerated-carrier trapping at a low interfacial electric field leads to photomultiplication with an ultrahigh external quantum efficiency (up to 104%). In contrast, mobile-ion polarization triggered by a high interfacial electric field results in ferroelectric-like memristive behaviour with both remarkable resistive on/off ratios and rectification ratios. The combination of the “soft-contact” enabled by rolled-up nanotechnology and the “ion reservoir” provided by the polymeric electrode opens up a novel strategy for integrating multi-functional molecular devices based on the synergistic electronic-ionic reaction to various stimuli.:List of abbreviations 6 Chapter 1 Introduction 8 1.1 Molecular electronics: a brief history 8 1.2 Motivation: why molecular electronics? 9 1.3 Objectives: developing integrated functional molecular devices 14 1.4 Dissertation structure 15 Chapter 2 Fabrication and characterization methods 17 2.1 Core nanotechnology adopted in this thesis: rolled-up nanomembrane contacts 17 2.2 Fabrications 18 2.2.1 Photolithography 18 2.2.2 Spin-coating 23 2.2.3 Electron-beam deposition 24 2.2.4 Sputter deposition 25 2.2.5 Atomic layer deposition 27 2.2.6 Low-temperature evaporation 28 2.3 Characterizations 30 2.3.1 Atomic force microscopy 30 2.3.2 Photoelectron spectroscopy 32 2.3.3 X-ray diffraction 35 Chapter 3 Integrated molecular rectifiers 37 3.1 Introduction 37 3.2 Construction of the organic heterojunction 39 3.3 Microfabrication of the molecular diode 46 3.4 Origination of the rectification 54 3.5 Frequency performance 61 3.6 Discussion 63 Chapter 4 Integrated process-programmable molecular devices 66 4.1 Introduction 66 4.2 Design and microfabrication of the molecular devices 69 4.2.1 Top tubular metallic electrodes 69 4.2.2 Bottom finger polymer electrodes 71 4.3 Function I: Molecular photomultiplication photodiodes 75 4.3.1 Traditional photodiodes and photomultiplication photodiodes 75 4.3.2 Performance of molecular photomultiplication photodiodes 78 4.3.3 Transition voltage spectroscopy 84 4.4 Function II: Molecular bipolar memristors 86 4.4.1 Ion doping-assisted injection 86 4.4.2 Performance of the molecular bipolar memristors 88 4.4.3 Mechanism of the resistance switching 97 4.5 Mechanism of the electric-field-driven transition 106 4.6 Conclusions 108 Chapter 5 Conclusions and outlook 110 5.1 Conclusions 110 5.1.1 Fully integrated molecular rectifiers 110 5.1.2 Fully integrated process-programmable molecular devices 111 5.2 Outlook 111 5.2.1 Improve the yield of the integrated molecular devices 111 5.2.2 Develop integrated molecular functional devices 112 References 113 List of figures and tables 129 Selbständigkeitserklärung 134 Theses 135 Acknowledgments 138 Research achievements 140 Curriculum-vitae 142

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No. of bitstreams: 1 torikai_K_me_bauru.pdf: 9782713 bytes, checksum: 3775eee15d15983b2b404989e8170b7b (MD5) Previous issue date: 2018-12-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A eletrônica orgânica mostrou-se comercialmente viável e competitiva, já sendo integrada em diversas tecnologias, e.g., displays flexíveis de OLED, painéis solares de grande área, dispositivos biocompatíveis/vestíveis, entre outras. A utilização de materiais orgânicos na fabricação de dispositivos eletrônicos explora vantagens como: flexibilidade mecânica, baixas temperaturas de processamento e possibilidade de se implementar melhorias e ajustes por meio de sínteses químicas. Entretanto, a eletrônica inorgânica já bem estabelecida ainda se destaca na área da eletrônica robusta, uma vez que os semicondutores orgânicos (OSCs) são bastante suscetíveis a condições mais extremas, como exposição a gases e radiação. Nesse sentido, a tecnologia de nanomembranas autoenroladas (NM) tem mostrado, nos últimos anos, um grande potencial na fabricação de dispositivos híbridos ultracompactos em uma arquitetura inédita para transistores orgânicos de filmes finos (OTFTs). A partir das técnicas tradicionais de microfabricação—fotolitografia, deposição de filmes finos—fabricou-se OTFTs sobre NMs que, uma vez liberadas do substrato através da remoção sistemática de uma camada de sacrifício, remodelam os dispositivos em uma arquitetura tubular tridimensional, reduzindo a área ocupada em aproximadamente 90% e protegendo os OSCs da área ativa do OTFT entre as múltiplas voltas das NMs. Assim, mostrou-se que a arquitetura confere novas propriedades aos OTFTs sem prejudicar as propriedades elétricas, suportando centenas de ciclos de compressão mecânica e mostrando-se resistentes a radiação ultravioleta e a vapores agressivos, como a amônia. Por fim, para validar a arquitetura de OTFT inédita, mostra-se que a estratégia utilizada é válida para diferentes OSCs e pode ser utilizada na fabricação de circuitos eletrônicos mais complexos a partir da associação de múltiplos dispositivos, como o inversor aqui apresentado. / In the recent years, the organic electronics’ commercial viability and competitiveness became apparent, integrating a diversity of technologies, e.g., OLED flexible displays, large-area solar panels and biocompatible and wearable devices. The manufacturing of electronic devices with organic materials aims at exploiting inherent characteristics— mechanical flexibility, low processing temperatures and the potential of boosting and tailoring specific properties through chemical synthesis. However, there’s still a gap between the well-established inorganic and the organic electronics concerning applications on rugged electronics, since the organic semiconductors (OSCs) are very susceptible to harsh conditions, e.g., exposition to UV radiation and gases. In this sense, recent advances on strained nanomembrane (NM) technology has shown enormous potential in the manufacturing of hybrid ultracompact devices in a novel organic thin-film transistor (OTFT) architecture. Through traditional microfabrication techniques—photolithography, thin-film deposition—OTFTs were fabricated on top of strained NMs, which promotes a reshaping of the devices into a 3D tubular architecture when released from the substrate. This process promotes a reduction in about 90% of the footprint area while protecting the OSC in the active area in between the multiple device windings. Therefore, the OTFTs have been endowed with new proprieties without loss of electric performance, while enduring hundreds of mechanical compression cycles and showing increased resilience against UV radiation and hazardous vapors, such as ammonia. Finally, to validate this novel OTFT architecture, this strategy has been shown to be valid for different OSCs and can be used to manufacture electronic circuits through the association of multiple devices, such as the inverter reported in this study. / CAPES: Código de financeamento 001 / FAPESP: Jovem Pesquisador 2014/25979-2

Over the past two decades, organic semiconductors played a growing part as active layers in several electronic systems such as sensors, field‑effect transistors or light emitting diodes to cite a few. In fact, organic materials offer a high versatility and flexibility. However, pure organic systems often lack stability and robustness, which can be overcome by combining them with inorganic scaffolds. In this work, a conducting polymer, polypyrrole (PPy) is employed to create new sensor elements based on the combination of both inorganic and organic layers. Electrical measurements, infrared spectroscopy and current sensing atomic force microscopy provides a better understanding of the polymer behavior upon immersion in aqueous solutions. The observed discharge in water leads to a straightforward application of the device as an in‑flow sensor for several acids like HCl, H2SO4 and H3PO4. The wide range of sensing concentrations as well as the low detection limit place the present detector among the best reported so far in the literature. In a further step to turn towards lab‑in‑a‑tube devices, tubular‑shaped‑integrated microelectrodes are developed by using the rolled‑up technology. As a proof of concept, the successful integration of PPy as an active layer and its use as a gas sensor for volatile organic compounds (VOCs) is demonstrated. Finally, by adapting the rolled‑up top electrodes, as developed by Bof Bufon et al. for self‑assembled monolayers (SAMs), thin PPy films (<50 nm) are vertically contacted and their electrical characteristics measured as a function of temperature and electric field. From the transport investigations, it is observed that an insulating‑to‑metallic transition occurs in the polymeric film by increasing the bias voltage. Other molecular layers like CuPc can be incorporated in these platforms, opening the way towards emerging organic devices.

Miniaturization is a key technological approach in current times. The most prominent examples of miniaturization are personal computers and mobile phones, but we observe miniaturization in other aspects of life, with the most recent example being small portable corona test kits. In science a big part of miniaturization focuses on detectors: to make them portable, to make them integrable into bigger, multi-function systems or to enable detection of smaller and smaller samples. For many experimental techniques highly sensitive and compact devices are already available, one of the extreme examples being single photon detectors. Compared to that, miniaturization of nuclear magnetic resonance (NMR) has still a long way to go in terms of both size and sensitivity. Recently, the successful miniaturization of an NMR coil was presented: on top of a flat polymeric bilayer a metallic layout is patterned. In an aqueous solution, one polymer layer absorbs water and swells, which induces strain between the two polymeric layers. This strain is released by a self-rolling-up of the bilayer, and the metal layer transforms into a microcoil. Such microcoils were successfully used for impedimetric measurements, as antennas, and as mentioned for NMR, but their performance in the latter was far from optimal. This thesis focuses on the optimization of rolled-up microcoils (RUMs) for NMR spectroscopy, with the goal to produce high-resolution and, most importantly, high-sensitivity microcoils. The performance of the microcoil can be expressed in three parameters, namely the spectral linewidth, the (normalized) limit of detection and the damping of a nutation curve, which was not a key parameter for this thesis. Both the microcoil design and the roll-up process have an influence on the quality of a RUM. For an optimal roll-up process, the polymeric bilayer layout needed some adjustment. The rolling process itself was improved through an addition of supporting structures on top of the bilayer, which resulted in tightly rolled tubes with a well-defined diameter. The coil layout was selected from several simple layouts. This layout was then optimized with the help of experiments and simulations. For example, an improvement in resolution was achieved through a reduction of the susceptibility of the metal. Finally, the coil was embedded into a microfluidic chip. This chip allows an easy sample supply into the coil interior and protects the coil from damage. As a side effect, the chip has a positive influence on the resolution of the detector. The best RUMs have a volume of only 1.5 nl, show a linewidth of only 8 ppb and a normalized limit of detection of 0.6 nmol√Hz at 600 MHz. The achieved resolution and sensitivity allow to resolve a 1H ethanol spectrum fully in a single measurement of 6 s duration. Compared to a standard shimmed NMR detector, where the linewidth is 0.65 ppb and the nLOD 10 nmol√Hz, the RUMs linewidth still needs some improvement, but the limit of detection is already an order of magnitude smaller. Combined with the fact that the limit of detection improves with linewidth, this shows the far superior sensitivity of RUMs compared to standard setups. A comparison with literature is also very promising, where optimized RUMs compete with the best published microcoils. Additionally, RUMs can be produced en masse, with, at the moment, four coils fitting on a single 50 x 50 mm2 glass substrate, while the best other microcoils were all made for single, specific experiments one at a time. And finally, the here presented recipe for self-assembled, RUMs is easily adaptable to even smaller sample volumes and to other coil layouts. It can be used to produce matching gradient coil systems and is a guideline on how to combine NMR and other techniques while maintaining a high NMR performance.:Introduction Nuclear magnetic resonance 1 NMR principle 1.1 A single nucleus in a magnetic field 1.2 Multiple spins in external field 1.3 Spins in natura 1.4 Typical liquid state spectrum 1.5 Typical NMR setup 2 Properties of an NMR detector 2.1 Quality of rf-field 2.2 Resolution 2.3 Signal-to-noise ratio 2.4 How to optimize a microcoil 3 Existing microdetectors 3.1 Solenoids 3.2 Saddle coils 3.3 Flat coils 3.4 Striplines/Microslots 4 Comparing microdetectors 4.1 The limit of detection 4.2 Performance of published microcoils Self-assembly 5 What is self-assembly? 6 Self-assembly in microfabrication 6.1 Macroscopic self-assembly 6.2 Self-rolled tubes 7 Self-assembly of rolled-up microcoils 7.1 Working principle 7.2 Experimental methods for self-assembly 8 Encapsulating rolled-up tubes 8.1 Microfluidics 8.2 Microfluidic chip 8.3 Experimental methods for encapsulation Rolled-up microcoils 9 Fabrication 9.1 Bilayer 9.2 Coil geometry 9.3 Metal stack 9.4 Supporting elements 9.5 Rolling process 9.6 Final layout 9.7 Microfluidic integration 10 Reducing susceptibility-induced field distortions 10.1 Simulating field distortions 10.2 Influence of the coil shape 10.3 Susceptibility matching 11 NMR performance 11.1 Measurement setup 11.2 Quality of rf-field 11.3 Resolution and sensitivity 11.4 Comparison to published microcoils 12 Outlook 12.1 Further improvements to rf-field, FWHM and nLOD 12.2 New coil shapes 12.3 New applications Summary Appendix A Simulation and maths A.1 Filling factor and rf-homogeneity A.2 Nutation and rf-homogeneity A.3 FT of one-sided exponential A.4 DFT A.5 Programs B Protocols B.1 Polymeric platform B.2 Metal layers C Test protocols C.1 Wet etching D Calculations for nLODs

Gegenwärtige Bestrebungen materialwissenschaftlicher Forschung beschäftigen sich unter anderem mit der Überführung zweidimensionaler Elemente elektronischer, optischer, plasmonischer oder magnetischer Funktionalität in den dreidimensionalen (3D) Raum. Dieser Ansatz vermag mittels Krümmung und struktureller Topologie bereits vorhandene Eigenschaften abzuändern beziehungsweise neue Funktionalitäten bereitzustellen. Vor allem Vektoreigenschaften wie die Magnetisierung kondensierter Materie lassen sich aufgrund der Brechung der Inversionssymmetrie in gekrümmten Flächen stark beeinflussen. Neben der Entwicklung diverser Vorgänge zur Herstellung 3D magnetischer Gegenstände sind geeignete Untersuchungsmethoden wie beispielsweise tomografische Abbildungen der Magnetisierung von Nöten, die maßgeblich die physikalischen Eigenschaften bestimmen. Die vorliegende Dissertationsschrift befasst sich mit der Abbildung von magnetischen Domänen in 3D gekrümmten Dünnschichten beruhend auf dem Effekt des zirkularen magnetischen Röntgendichroismus (XMCD). Die in diesem Zusammenhang entwickelte magnetische Röntgentomografie (MXT) basierend auf weicher Röntgenmikroskopie stellt eine zu Elektronenholografie und Neutronentomografie komplementäre Methodik dar, welche großes Anwendungspotential in der elementspezifischen Untersuchung magnetischer gekrümmter Flächen mit örtlicher Auflösung im Nanometerbereich aufweist. Die Schwierigkeit der Interpretation von Abbildungen magnetischer Strukturen in gekrümmten Flächen rührt von der Dreidimensionalität und der Vektoreigenschaft der Magnetisierung her. Die hierzu notwendigen Kenntnisse sind anhand von zwei topologisch verschiedenen Flächen in Form hemisphärischer Kappen und hohler Zylinder erschlossen worden. Die praktische Anwendung von MXT ist abschließend anhand der Rekonstruktion magnetischer Domänen in aufgerollten Dünnschichten mit zylindrischer Form verdeutlicht. / One of the foci of modern materials sciences is set on expanding conventional two-dimensional electronic, photonic, plasmonic and magnetic devices into the third dimension. This approach provides means to modify conventional or to launch novel functionalities by tailoring curvature and three-dimensional (3D) shape. The degree of effect is particularly high for vector properties like the magnetization due to an emergent inversion symmetry breaking. Aside from capabilities to design and synthesize 3D magnetic architectures, proper characterization methods, such as magnetic tomographic imaging techniques, need to be developed to obtain a thorough understanding of the system’s response under external stimuli. The main objective of this thesis is to develop a visualization technique that provides nanometer spatial resolution to image the peculiarities of the magnetic domain patterns on extended 3D curved surfaces. The proposed and realized concept of magnetic soft X-ray tomography (MXT), based on the X-ray magnetic circular dichroism (XMCD) effect with soft X-ray microscopies, has the potential to become a powerful tool to investigate element specifically an entirely new class of 3D magnetic objects with virtually any shape and magnetization. Imaging curved surfaces meets the challenge of three-dimensionality and requires a profound understanding of the recorded XMCD contrast. These experiences are gained by visualizing magnetic domain patterns on two distinct 3D curved surfaces, namely magnetic cap structures and rolled-up magnetic nanomembranes with cylindrical shape. The capability of MXT is demonstrated by reconstructing the magnetic domain patterns on 3D curved surfaces resembling hollow cylindrical objects.