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Del A: Polyetylentereftalat fibrer I detta arbete presenteras olika metoder för att framställa monofilament av polyetylentereftalat (PET) (diameter: 30-50 µm) med en radiell gradient. Nyutvecklad Raman-spektroskopiteknik har använts för att kartlägga dessa inducerade radiella gradienter i t.ex. kristallinitet. På liknande sätt har FTIR-ATR teknik modifierats och anpassats för att studera ytegenskaperna hos dessa filament. Industriella filamentprover och egna smältspunna PET-filament har framgångsrikt modifierats med användning av olika termiska och kemiska behandlingar för att erhålla fibrer med förbättrade mekaniska egenskaper och minskad fibrillering. De strukturella förändringar som uppträdde i filamenten på mikroskopisk nivå karakteriserades med bl a infraröd analys, termisk analys, Raman-mikroskopi och röntgenteknik (SAXS och WAXD). Tester av fibrilleringsegenskaper utfördes av industriella partners med egenutvecklad teknik följt av testning av masterbatch-fibrer på en vävningssimulator. Resultaten i laboratorieskala avslöjade fibrernas strukturella anisotropi och radiella gradienter, vilka visade en minskad fibrillering med en viss inverkan på de mekaniska egenskaperna.  Del B: Poly(3-hydroxybutyrat) fibrer Detta arbete presenterar studier av poly(3-hydroxybutyrat) (P3HB) fibrer med reversibla strukturförändringar. Tidigare studier har visat att kristallisationen hos P3HB fibrer i huvudsakligen sker i ortorombisk α-kristallform. Stress-anlöpning resulterar dock i en förändring i beteendet hos P3HB-materialet. Strukturen hos P3HB fibrer består av amorfa och kristallina regioner samt en mesofas. Mesofasen antas vara belägen mellan α-kristallerna och uppträder som starkt orienterade bindningskedjor, s k “tie-chains”. Denna studie syftar till att observera effekten av stress-anlöpning på mesofasen och dess beroende av anlöpningsförhållandena. Förändringarna i mesofasen observeras med en anpassad och polariserad Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR) samt med Differential Scanning Calorimetry (DSC). Resultaten från ATR-FTIR visar att mesofasen är närvarande i spunna och högt stress-anlöpta fibrer, medan den är frånvarande i fibrer som är lågt stress-anlöpta. Mesofasen kan emellertid återupptas i lågt stress-anlöpta fibrer genom dragning. In situ ATR-FTIR användes för att studera förändringarna i materialbeteendet under en dragningsprocess för att observera periodiciteten i förekomsten av mesofasen. Det visade sig att förekomsten av mesofasen är en starkt reversibel process som observeras som en funktion av topparnas intensitet i ATR-FTIR. / Part A: Poly(ethylene terephthalate) fibres In this work, various methods to produce Poly(ethylene terephthalate) (PET) monofilaments (diameter: 30-50µm) with a radial gradient are presented along with a newly developed Raman spectroscopy technique to map these induced radial gradients in e.g. crystallinity. On similar lines, FTIR-ATR technique has been modified and adapted to study the surface properties of these fine filaments. Industrial filament samples and in-house melt-spun PET filaments have been successfully modified using various thermal and chemical treatments to obtain fibres with improved mechanical properties and reduced fibrillation. The structural changes occurring in the filaments on the microscopic level were characterized using infrared analysis, thermal analysis, Raman microscopy and X-ray techniques (SAXS and WAXD) among others. The fibrillation properties were tested by the industrial partners using a technique developed in-house followed by testing of masterbatch fibres on a weaving simulator. Lab-scale results revealed the structural anisotropy and radial gradient maps of the fibres which also demonstrated reduced fibrillation with some impact on mechanical properties also being observed. Part B: Poly(3-hydroxybutyrate) fibres This work presents studies on poly(3-hydroxybutyrate) (P3HB) fibres with reversible structural changes. Previously reported literature shows that crystallization of P3HB fibres takes place majorly in the orthorhombic α-crystal form. However, the stress-annealing results in a change of the material behaviour of P3HB. P3HB fibres compose of amorphous regions, crystalline regions and mesophase in their structure. The mesophase is supposed to be located in between the α-crystals of the material as highly oriented tie-chains. This study targets to observe the effect of stress-annealing of the mesophase present in the P3HB fibres and its dependence on the annealing conditions. The changes in the mesophase content are observed with the help of a highly adapted polarized Attenuated Total Reflection Fourier Transform Infrared spectroscopy (ATR-FTIR) and Differential Scanning Calorimetry (DSC). The presented results from polarized ATR-FTIR show that the mesophase is present in as-spun and high stress annealed fibres while it is absent in fibres annealed with low stress. However, the mesophase can be re-obtained in low stress annealed fibres through tensile drawing. In-situ ATR-FTIR was utilized to study the changes in the material behaviour during a tensile drawing process to observe the cyclicity in the occurrence of the mesophase. It was found that the existence of mesophase is a highly reversible process observed as a function of the peak intensities of the polarized ATR-FTIR spectroscopy.

Integration of high-K Metal-Insulator-Metal (MIM) capacitors in the Back-end-of-line (BEOL) is a topic of interest for the further development of the process at KTH Royal Institute of Technology. MIM-capacitors benefit from having constant capacitance values over a range of voltages and/or frequencies. One significant limitation in the development of better MIM-capacitors is the temperature consideration for BEOL processes. For the process at KTH Institute of Technology the temperature should not exceed 600 °C, as this would damage underlying devices. This work aims to fabricate aluminium oxide MIM-capacitors as a standard BEOL process performed at low temperature, which has been achieved via atomic layer deposition (ALD). The fabricated aluminium oxide MIM-capacitors had a good quality factor, series resistance and low dissipation. The capacitance for a 10 nm thick aluminium oxide insulator layer was 1 µF/cm2, which exceeds the set requirement. This work also aimed to make ferroelectric aluminium doped hafnium oxide MIM-capacitors using ALD. The doping ratio was varied in ALD as this had been found to affect formation of the ferroelectric crystal phase after a rapid thermal annealing step. Three wafers of 20 nm thick hafnium oxide and differing ratios were found to not be ferroelectric. The intermediate doping ratio was found to appear slightly anti-ferroelectric. A 10 nm thick doped hafnium oxide of intermediate doping was also fabricated and was found to be ferroelectric with a remnant polarisation of 1 µC/cm2. Though this polarisation is relatively small, it shows that top electrode induced strain due to lattice mismatch could be responsible for the ferroelectric properties of the capacitor. The quality of the hafnium based capacitors seemed worse in comparison to the aluminium oxide capacitors, which is suspected to be due to oxygen vacancies, resulting in a high loss tangent. While this first experiment showed promising results, the ferroelectric remnant polarisation should be increased by an order of magnitude and the electrical benchmark values should be improved before these hafnium oxide MIM-capacitors can be used in the BEOL process. / Integratie van high-K MIM-condensatoren in de Back-end-of-line (BEOL) is een onderwerp van belang voor de ontwikkeling van het proces bij de KTH. MIM-condensatoren profiteren van een constante capaciteitswaarde over een reeks spanningen en/of frequenties. Een belangrijke beperking bij de ontwikkeling van betere MIM-condensatoren is het temperatuur limiet voor BEOL-processen. Bij de KTH moet de temperatuur niet hoger zijn dan 600 °C, omdat dit de onderliggende apparaten zou beschadigen. Dit werk heeft tot doel aluminiumoxide MIM-condensatoren te fabriceren als een standaard BEOL-proces met lage temperatuur, en heeft dit inderdaad bereikt via atomaire laagafzetting (ALD). De gefabriceerde aluminiumoxide MIM-condensatoren hadden een goede kwaliteitsfactor, serieweerstand en lage dissipatie. De capaciteit voor een 10 nm dikke aluminiumoxide-isolatorlaag was 1µF/cm2, hoger dan de gestelde eisen. Dit werk was ook gericht op het maken van ferro-elektrische aluminium gedoteerde hafniumoxide MIM-condensatoren met behulp van ALD. De doteringsverhouding werd gevarieerd in ALD, aangezien bleek dat dit de vorming van de ferro-elektrische kristalfase faciliteerde na een snelle thermische gloeistap. Drie wafers van 20 nm dik hafniumoxide en verschillende verhoudingen bleken niet ferro-elektrisch te zijn. De tussenliggende doteringsverhouding bleek enigszins anti-ferro-elektrisch te zijn. Een 10 nm dik gedoteerd hafniumoxide met intermediaire dotering werd ook gefabriceerd en bleek ferro-elektrisch te zijn met een restpolarisatie van 1 µC/cm2. Hoewel deze polarisatie relatief klein is, toont het aan dat de door de topelektrode geïnduceerde spanning als gevolg van roostermismatch verantwoordelijk zou kunnen zijn voor de ferro-elektrische eigenschappen van de condensator. De kwaliteit van de op hafnium gebaseerde isolator leek slechter in vergelijking met die van aluminiumoxide, hetgeen kan worden toegeschreven aan gebrek van zuurstof in het rooster, wat in een groot verlies resulteert. De ferro-elektriciteit moet met een orde van grootte worden verhoogd en de elektrische benchmarks moeten ook verhoogd worden voordat deze hafniumoxide MIM-condensatoren kunnen worden gebruikt in het BEOLproces. Sleutelwoorden: atomaire laagafzetting (ALD), Ferro-elektrisch, Metaal-Isolator- Metaal (MIM) condensator, lage temperatuur, snelle thermische gloeiing.

Quantum computing is a form of computation that exploits quantum mechanical phenomena for information processing, with promising applications (among others) in optimization and machine learning. Indeed, quantum machine learning is currently one of the most popular directions of research in quantum computing, offering solutions with an at-least-theoretical advantage compared to the classical counterparts. Nevertheless, the quantum devices available in the current Noisy Intermediate-Scale Quantum (NISQ) era are limited in the number of qubits and significantly affected by noise. An interesting alternative to the current prototypes of general-purpose quantum devices is represented by quantum annealers, specific-purpose quantum machines implementing the heuristic search for solving optimization problems known as quantum annealing. However, despite the higher number of qubits, the current quantum annealers are characterised by very sparse topologies. These practical issues have led to the development of hybrid classical-quantum schemes, aiming at leveraging the strengths of both paradigms while circumventing some of the limitations of the available devices. In this thesis, several hybrid classical-quantum algorithms for optimization and machine learning are introduced and/or empirically assessed, as the empirical evaluation is a fundamental part of algorithmic research. The quantum computing models taken into account are both quantum annealing and circuit-based universal quantum computing. The results obtained have shown the effectiveness of most of the proposed approaches.

L’agriculture verticale permet de contrôler presque totalement les conditions pour croître des plantes, qu’il s’agisse des conditions météorologiques, des nutriments nécessaires à la croissance des plantes ou même de la lutte contre les parasites. Il est donc possible de trouver et de définir des paramètres susceptibles d’augmenter le rendement et la qualité des récoltes et de minimiser la consommation d’énergie dans la mesure du possible. À cette fin, ce mémoire présente des algorithmes d’optimisation tels qu’une version améliorée du recuit simulé qui peut être utilisée pour trouver et donner des lignes directrices pour les paramètres de l’agriculture verticale. Nous présentons égalementune contribution sur la façon dont les algorithmes de contrôle, p. ex. l’apprentissage par renforcement profond avec les méthodes critiques d’acteurs, peuvent être améliorés grâce à une exploration plus efficace en prenant en compte de l’incertitude épistémique lors de la sélection des actions. cette contribution peut profiter aux systèmes de contrôle conçus pour l’agriculture verticale. Nous montrons que notre travail est capable de surpasser certains algorithmes utilisés pour l’optimisation et le contrôle continu. / Vertical farming provides a way to have almost total control over agriculture, whether it be controlling weather conditions, nutrients necessary for plant growth, or even pest control. As such, it is possible to find and set parameters that can increase crop yield, and quality, and minimize energy consumption where possible. To that end, this thesis presents optimization algorithms such as an enhanced version of Simulated Annealing that can be used to find and give guidelines for those parameters. We also present work on how real-time control algorithms such as Actor-Critic methods can be made to perform better through more efficient exploration by taking into account epistemic uncertainty during action selection which can also benefit control systems made for vertical farming. We show that our work is able to outperform some algorithms used for optimization and continuous control.

Oxygen in single crystalline antimony triselenide (Sb₂Se₃) is addressed by infrared (IR) absorption spectroscopy. Measurements conducted on Sb₂Se₃ samples doped—during growth, post-growth annealing in the O₂ ambient, or by O ion implantation—with ¹⁶O reveal an IR absorption line at 527 cm⁻¹ (10 K). Substitution of ¹⁶O by ¹⁸O “red”-shifts the signal down to 500 cm⁻¹ based on which the line is assigned to a local vibrational mode of an isolated oxygen defect. Annealing of O-enriched samples in hydrogen atmosphere at temperatures above 380 °C results in the suppression of the 527-cm⁻¹ line and concurrent appearance of the signals due to hydroxyl groups, suggesting formation of oxygen-hydrogen complexes. The configuration of the 527-cm⁻¹ oxygen center is discussed.