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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
161

Towards Development of Smart Nanosensor System To Detect Hypoglycemia From Breath

Sanskar S Thakur (8816885) 08 May 2020 (has links)
<div>The link between volatile organic compounds (VOCs) from breath and various diseases and specific conditions has been identified since long by the researchers. Canine studies and breath sample analysis on Gas chromatography/ Mass Spectroscopy has proven that there are VOCs in the breath that can detect and potentially predict hypoglycemia. This project aims at developing a smart nanosensor system to detect hypoglycemia from human breath. The sensor system comprises of 1-Mercapto-(triethylene glycol) methyl ether functionalized goldnanoparticle (EGNPs) sensors coated with polyetherimide (PEI) and poly(vinylidene fluoride -hexafluoropropylene) (PVDF-HFP) and polymer composite sensor made from PVDF-HFP-Carbon Black (PVDF-HFP/CB), an interface circuit that performs signal conditioning and amplification, and a microcontroller with Bluetooth Low Energy (BLE) to control the interface circuit and communicate with an external personal digital assistant. The sensors were fabricated and tested with 5 VOCs in dry air and simulated breath (mixture of air, small portion of acetone, ethanol at high humidity) to investigate sensitivity and selectivity. The name of the VOCs is not disclosed herein but these VOCs have been identified in breath and are identified as potential biomarkers for other diseases as well. </div><div> </div><div> The sensor hydrophobicity has been studied using contact angle measurement. The GNPs size was verified using Ultra-Violent-Visible (UV-VIS) Spectroscopy. Field Emission Scanning Electron Microscope (FESEM) image is used to show GNPs embedded in the polymer film. The sensors sensitivity increases by more than 400% in an environment with relative humidity (RH) of 93% and the sensors show selectivity towards VOCs of interest. The interface circuit was designed on Eagle PCB and was fabricated using a two-layer PCB. The fabricated interface circuit was simulated with variable resistance and was verified with experiments. The system is also tested at different power source voltages and it was found that the system performance is optimum at more than 5 volts. The sensor fabrication, testing methods, and results are presented and discussed along with interface circuit design, fabrication, and characterization.</div>
162

Synthese photoreaktiver Polymere zur optischen Strukturierung dünner Schichten

Georgi, Ulrike 09 May 2014 (has links)
Diese Arbeit beschäftigt sich mit der Synthese neuer photoreaktiver Polymere, die bei Bestrahlung mit Licht (Hg-Dampflampe, fs-gepulster Ti:Sa-Laser) definierte Reaktionen durchlaufen. Mittels kontrolliert-radikalischer Polymerisation und anschließender polymeranaloger Reaktion wurden verschiedene Azobenzen-Derivate, Arylazosulfonat-Derivate und photolabil geschützte Aminogruppen (Nitroveratryloxycarbonyl, Nvoc) in Methacrylat-Polymere eingeführt. Diese Strukturen wurden ausführlich hinsichtlich ihrer Struktur und vor allem ihrer photochemischen Eigenschaften (Extinktionskoeffizienten, Zerfallskinetik) untersucht. Dünne Schichten (d<30nm) der so hergestellten Materialien wurden bei der Entwicklung einer neuen photolithographischen Methode, der plasmonischen Nanolithographie, eingesetzt.:INHALTSVERZEICHNIS ABBILDUNGSVERZEICHNIS TABELLENVERZEICHNIS ABKÜRZUNGS- UND SYMBOLVERZEICHNIS 1 EINLEITUNG UND ZIELSTELLUNG 2 THEORETISCHE GRUNDLAGEN 2.1 PHOTOREAKTIVE POLYMERE 2.1.1 Azobenzenhaltige Polymere und deren Anwendungen 2.1.2 Arylazosulfonathaltige Polymere und deren Anwendungen 2.1.3 Photolabil geschützte Amine in Polymeren und zur Oberflächenstrukturierung 2.2 NICHT-LINEAR OPTISCHE EFFEKTE - FREQUENZVERDOPPLUNG 2.3 OBERFLÄCHENPLASMONENRESONANZ UND SHG AN METALLISCHEN NANOPARTIKELN 2.4 PHOTOCHEMISCHE STRUKTURIERUNG DÜNNER SCHICHTEN 2.5 NANOLITHOGRAPHISCHE STRUKTURIERUNG MITTELS PLASMONISCHER EFFEKTE AN METALLNANOSTRUKTUREN 3 ERGEBNISSE UND DISKUSSION 3.1 AZOBENZENHALTIGE POLYMERE 3.1.1 Synthese niedermolekularer Azobenzen-Derivate 3.1.2 Anbindung an Polymermatrix 3.1.3 Photochemische matrixabhängige Untersuchung der Isomerisationskinetik 3.1.4 Bestrahlung in dünnen Schichten mit gepulstem Femtosekunden-Laser 3.2 ARYLAZOSULFONATHALTIGE POLYMERE 3.2.1 Kontrolliert-radikalische Polymerisation von Arylazosulfonat-Monomeren 3.2.1.1 Synthese der arylazosulfonathaltigen Monomere 3.2.1.2 RAFT-Polymerisation von (AS-Mon2) 3.2.2 Polymeranaloge Einführung von Arylazosulfonateinheiten 3.2.3 Präparation und Bestrahlung dünner Schichten 3.3 PHOTOLABIL GESCHÜTZTE AMINOPOLYMERE 3.3.1 Synthese von statistischen Nvoc-geschützten Aminocopolymeren 3.3.1.1 Anbindung des Nvoc-geschützten Amins über Esterbindung 3.3.1.2 Anbindung des Nvoc-geschützten Amins über Reaktion mit Nvoc-Cl 3.3.2 Nvoc-haltige Diblockcopolymere 3.3.2.1 Synthese von P(MMA-co-GMA)-b-P(MMA-co-NvocCMS) 3.3.2.2 Synthese von P(MMA-co-MAA)-b-P(MMA-co-NvocAEMA) 3.3.3 Präparation dünner Schichten der (Block-)Copolymere 3.3.4 Bestrahlung mit gepulstem Femtosekunden-Laser 4 ZUSAMMENFASSUNG UND AUSBLICK 5 EXPERIMENTALTEIL 5.1 ANALYTISCHE METHODEN 5.2 AUFBAU FÜR DIE FS-LASER-BESTRAHLUNG 5.3 VERWENDETE CHEMIKALIEN 5.4 SYNTHESEN 5.4.1 Azobenzen-Derivate 5.4.1.1 Niedermolekulare Verbindungen 5.4.1.2 Polymerisationen und polymeranaloge Reaktionen 5.4.2 Arylazosulfonate 5.4.2.1 Niedermolekulare Verbindungen 5.4.2.2 Freie radikalische Polymerisation 5.4.2.3 RAFT-Polymerisationenen 5.4.2.4 Polymeranaloge Reaktion 5.4.3 Nvoc-geschützte (Block-)Copolymere 5.4.3.1 Niedermolekulare Verbindungen 5.4.3.2 Polymerisationen 5.4.3.3 Polymeranaloge Reaktionen 5.5 WAFERREINIGUNG UND PRÄPARATION DÜNNER SCHICHTEN LITERATURVERZEICHNIS DANKSAGUNG VERSICHERUNG
163

Advances in Organic Displays and Lighting: Towards Planar Lithographic Integration of Organic Light-Emitting Diodes

Krotkus, Simonas 31 May 2017 (has links)
This work focusses on the advances of organic light-emitting diodes (OLEDs) for large area display and solid-state-lighting applications. OLED technology has matured over the past two decades, aided by the rapid advances in development of the novel material and device concepts. State-of-the-art OLEDs reach internal efficiencies of 100% and device lifetimes acceptable for commercial display applications. However, further improvements in the blue emitter stability and the device performance at the high brightness are essential for OLED technology to secure its place in the lighting market. As the current passing through the device increases, a rapid decrease in OLED efficiency, so-called efficiency roll-off, takes place, which hinders the use of OLEDs wherever high brightness is required. In addition, white OLEDs comprising multiple emitter molecules suffer from the emission colour change as the operating conditions are varied or as the devices age. Despite side-by-side structuring of the monochrome OLEDs could in principle circumvent most of bespoke issues, the limitations imposed by the shadow mask technique, employed to structure vacuum deposited films, renders such approach impractical for fabrication of the devices on a large scale. In order to address these issues, photolithographic patterning of OLEDs is implemented. Highly efficient state-of-the-art devices are successfully structured down to tens of micrometers with the aid of orthogonal lithographic processing. The latter is shown to be a promising alternative for the shadow mask method in order to fabricate the full-colour RGB displays and solid-state-lighting panels. Photo-patterned devices exhibit a virtually identical performance to their shadow mask counterparts on a large scale. The high performance is replicated in the microscale OLEDs by a careful selection of functional layer sequence based on the investigation of the morphological stability and solubility of vacuum deposited films. Microstructured OLEDs, fabricated in several different configurations, are investigated and compared to their large area counterparts in order to account for the observed differences in charge transport, heat management and exciton recombination in bespoke devices. The role of the Joule heat leading to the quenching of the emissive exciton states in working devices is discussed. Structuring the active OLED area down to 20 micrometer is shown to improve the thermal dissipation in such devices, thus enabling the suppression of the efficiency roll-off at high brightness in white-emitting electroluminescent devices based on side-by-side patterned OLEDs.:List of Publications 1 1 Introduction 5 2 Organic Semiconductors 9 2.1 Molecular Bonding 9 2.1.1 Intramolecular Interactions 10 2.1.2 Intermolecular Interactions 17 2.2 Optical Properties of Organic Semiconductors 23 2.2.1 Excited State Dynamics 26 2.3 Energy Transfer in Organic Solids 27 2.3.1 Förster Energy Transfer 29 2.3.2 Dexter Energy Transfer 30 2.4 Charge Transport Phenomena 31 2.4.1 Polarization and Energetic Disorder 31 2.4.2 Charge Transport Models 33 3 Electromagnetic Field Propagation in Layered Media 35 3.1 Maxwell's Equations 35 3.1.1 Wave Character of Electromagnetic Field 37 3.1.2 Energy of Electromagnetic Field 38 3.1.3 Boundary Conditions of Electromagnetic Fields 39 3.2 Reflection and Refraction of Plane Waves 40 3.2.1 Total Internal Reflection 43 3.3 Guided Optical Waves 44 3.3.1 Modes of Planar Waveguide 45 3.3.2 Multilayer Waveguides 49 3.3.3 Mode Coupling 53 3.4 EM Field in Presence of Charges 55 3.4.1 Volume Plasmons 58 3.4.2 Surface Plasmon Polaritons 58 3.4.3 Localized Plasmons 62 4 Organic Light-Emitting Diodes 65 4.1 Principle of Operation 65 4.1.1 Electroluminescence Efficiency 66 4.1.2 Charge Injection and Transport 66 4.1.3 Radiative Efficiency 68 4.1.4 Excited State Formation 69 4.1.5 Organic Emitters 71 4.1.6 Light Extraction 73 4.1.7 Efficiency Loss Mechanisms 74 4.2 Applications of OLEDs 76 4.2.1 Information Displays 76 4.2.2 Solid-State Lighting 77 4.2.3 OLED Based Sensors 77 4.3 OLED Structuring 79 4.3.1 Shadow Mask Patterning 79 4.3.2 Serial Printing 80 4.3.3 Unconventional Patterning Techniques 80 4.3.4 Photolithographic Patterning of OLEDs 81 4.3.5 Orthogonal Processing of Organic Semiconductors 83 5 Materials and Methods 87 5.1 Organic Functional Materials . 87 5.1.1 Hole Injection/Transport Layers 87 5.1.2 Electron Blocking Materials 88 5.1.3 Hole Blockers and Electron Transport Materials 88 5.1.4 Emitter Systems 90 5.1.5 Substrate and Electrodes 90 5.2 Device Fabrication 92 5.2.1 Vacuum Deposition 92 5.2.2 Photolithographic Structuring 92 5.3 Measurements 94 5.3.1 OLED Characterisation 94 5.3.2 Optical and Morphological Inspection 95 5.3.3 Calcium Conductance Test 95 5.3.4 Time-of-flight Spectroscopy 96 6 Orthogonal Patterning of Organic Semiconductor Films and Devices 97 6.1 Patterned Organic Films 97 6.2 Patterned Alq3 Based OLEDs 100 6.2.1 Direct Emitter Patterning 100 6.2.2 Cathode as Protection Layer 102 6.2.3 Impact of O2 Plasma Treatment 104 6.3 Summary 107 7 Photolithographic Structuring of State-of-the-Art p-i-n OLEDs for Full-Colour RGB Displays 109 7.1 Studied OLED Structures 109 7.2 HFE Compatibility Study 110 7.2.1 HFE Immersion Study 110 7.2.2 LDI-TOF-MS Analysis 112 7.3 Large area OLEDs 114 7.4 Microscale Devices 118 7.5 Bilayer Processing on p-i-n OLEDs 122 7.6 Summary 126 8 White Light from Photo-structured OLED Arrays 129 8.1 Fabrication of Micro-OLED Array 129 8.1.1 Structuring Procedure 130 8.1.2 Optical Device Optimisation 130 8.1.3 Choice of Hole Blocking and Electron Transport Layers 134 8.2 Performance of Microstructured Devices 143 8.2.1 Colour Temperature Tuning 143 8.2.2 Compatibility with Photo-patterning 145 8.2.3 Colour Stability 150 8.3 Summary 154 9 Efficiency Roll-off and Emission Colour of Microstructured OLEDs 155 9.1 Photolithographic Control of the Subunit Dimension 155 9.2 Control of the Emission Colour 156 9.3 Suppression of Efficiency Roll-off in Microscale Devices 157 9.4 Thermal Management in OLEDs 159 9.5 Modelling Impact of Joule Heat on Roll-off Characteristics 162 9.6 Summary 164 10 Conclusions and Outlook 165 10.1 Conclusions 165 10.2 Outlook 167 List of Abbreviations 171 List of Figures 173 List of Tables 177 Acknowledgements 179 Bibliography 181 / Die vorliegende Arbeit beschäftigt sich mit den neusten Errungenschaften von organischen Licht-emittierenden Dioden (OLEDs) für großflächige Beleuchtungs- und Displayanwendungen. Die OLED-Technologie hat sich in den letzten zwei Jahrzehnten, begünstigt von neuartigen Material- und Bauteilkonzepten, weit entwickelt. Im aktuellen Stand der Technik erreichen OLEDs sowohl interne Effizienzen von 100% als auch Lebensdauern die für die kommerzielle Nutzung in Displays ausreichend sind. Nichtsdestotrotz sind weitere Verbesserungen für die Stabilität blauer Emitter und die Leistungsfähigkeit bei hohen Leuchtstärken erforderlich, damit die OLED Technologie ihren Platz auf dem Markt behaupten kann. Mit steigender Stromstärke, die durch ein solches Bauteil fließt, sinkt die Effizienz rapide (der sogenannte Effizienz-Roll-Off), was die Nutzung von OLEDs verhindert, wann immer hohe Leuchtstärken erforderlich sind. Zusätzlich verändern weiße OLEDs ihre Farbkomposition durch die unterschiedliche Alterung der unterschiedlichen Emittermoleküle oder veränderte Einsatzbedingungen. Obwohl die laterale Strukturierung nebeneinander aufgebrachter, monochromer OLEDs diese Probleme umgehen könnte, ist diese Herangehensweise durch die aktuelle Schattenmasken-Technologie limitiert, welche zur Strukturierung vakuumprozessierter Dünnschichten eingesetzt wird, und somit unpraktikabel für die Massenproduktion. Um diese Problemstellungen zu umgehen, wird hier die photolithographische Strukturierung von OLEDs angewendet. Mithilfe der orthogonalen Lithographie können hocheffiziente Bauteile damit erfolgreich auf Größenordnungen von 10 Mikrometer strukturiert werden. Dies zeigt, dass die orthogonale Prozessierung eine vielversprechende Alternative für die Schattenmasken-Technologie darstellt und für die Herstellung von RGB-Displays und Beleuchtungspanelen geeignet ist. Photostrukturierte Bauteile zeigen dabei eine nahezu identische Leistungsfähigkeit zu solchen, die großffächig mittels Schattenmasken hergestellt wurden. Diese hohe Leistungsfähigkeit kann hierbei durch eine sorgfältige Auswahl der einzelnen funktionellen Schichten erreicht werden, welche auf Untersuchung von morphologischer Stabilität und Löslichkeit dieser Schichten basiert. Mikrostrukturierte OLEDs in verschiedenen Konfigurationen werden mit ihren großflächigen Gegenstücken verglichen, um beobachtete Abweichungen im Ladungstransport, der Wärmeverteilung, sowie der Exzitonenrekombination zu erklären. Die Rolle der Joule'schen Wärme, die zur Auslöschung der emittierenden Exzitonenzustände führt, wird hier diskutiert. Die thermische Dissipation kann dabei verbessert werden, indem die aktive Fläche der OLED auf 20 Mikrometer herunterstrukturiert wird. Folglich kann der Effizienz-Roll-Off bei hohen Leuchtstärken in lateral strukturierten weißen elektrolumineszenten Bauteilen unterdrückt werden.:List of Publications 1 1 Introduction 5 2 Organic Semiconductors 9 2.1 Molecular Bonding 9 2.1.1 Intramolecular Interactions 10 2.1.2 Intermolecular Interactions 17 2.2 Optical Properties of Organic Semiconductors 23 2.2.1 Excited State Dynamics 26 2.3 Energy Transfer in Organic Solids 27 2.3.1 Förster Energy Transfer 29 2.3.2 Dexter Energy Transfer 30 2.4 Charge Transport Phenomena 31 2.4.1 Polarization and Energetic Disorder 31 2.4.2 Charge Transport Models 33 3 Electromagnetic Field Propagation in Layered Media 35 3.1 Maxwell's Equations 35 3.1.1 Wave Character of Electromagnetic Field 37 3.1.2 Energy of Electromagnetic Field 38 3.1.3 Boundary Conditions of Electromagnetic Fields 39 3.2 Reflection and Refraction of Plane Waves 40 3.2.1 Total Internal Reflection 43 3.3 Guided Optical Waves 44 3.3.1 Modes of Planar Waveguide 45 3.3.2 Multilayer Waveguides 49 3.3.3 Mode Coupling 53 3.4 EM Field in Presence of Charges 55 3.4.1 Volume Plasmons 58 3.4.2 Surface Plasmon Polaritons 58 3.4.3 Localized Plasmons 62 4 Organic Light-Emitting Diodes 65 4.1 Principle of Operation 65 4.1.1 Electroluminescence Efficiency 66 4.1.2 Charge Injection and Transport 66 4.1.3 Radiative Efficiency 68 4.1.4 Excited State Formation 69 4.1.5 Organic Emitters 71 4.1.6 Light Extraction 73 4.1.7 Efficiency Loss Mechanisms 74 4.2 Applications of OLEDs 76 4.2.1 Information Displays 76 4.2.2 Solid-State Lighting 77 4.2.3 OLED Based Sensors 77 4.3 OLED Structuring 79 4.3.1 Shadow Mask Patterning 79 4.3.2 Serial Printing 80 4.3.3 Unconventional Patterning Techniques 80 4.3.4 Photolithographic Patterning of OLEDs 81 4.3.5 Orthogonal Processing of Organic Semiconductors 83 5 Materials and Methods 87 5.1 Organic Functional Materials . 87 5.1.1 Hole Injection/Transport Layers 87 5.1.2 Electron Blocking Materials 88 5.1.3 Hole Blockers and Electron Transport Materials 88 5.1.4 Emitter Systems 90 5.1.5 Substrate and Electrodes 90 5.2 Device Fabrication 92 5.2.1 Vacuum Deposition 92 5.2.2 Photolithographic Structuring 92 5.3 Measurements 94 5.3.1 OLED Characterisation 94 5.3.2 Optical and Morphological Inspection 95 5.3.3 Calcium Conductance Test 95 5.3.4 Time-of-flight Spectroscopy 96 6 Orthogonal Patterning of Organic Semiconductor Films and Devices 97 6.1 Patterned Organic Films 97 6.2 Patterned Alq3 Based OLEDs 100 6.2.1 Direct Emitter Patterning 100 6.2.2 Cathode as Protection Layer 102 6.2.3 Impact of O2 Plasma Treatment 104 6.3 Summary 107 7 Photolithographic Structuring of State-of-the-Art p-i-n OLEDs for Full-Colour RGB Displays 109 7.1 Studied OLED Structures 109 7.2 HFE Compatibility Study 110 7.2.1 HFE Immersion Study 110 7.2.2 LDI-TOF-MS Analysis 112 7.3 Large area OLEDs 114 7.4 Microscale Devices 118 7.5 Bilayer Processing on p-i-n OLEDs 122 7.6 Summary 126 8 White Light from Photo-structured OLED Arrays 129 8.1 Fabrication of Micro-OLED Array 129 8.1.1 Structuring Procedure 130 8.1.2 Optical Device Optimisation 130 8.1.3 Choice of Hole Blocking and Electron Transport Layers 134 8.2 Performance of Microstructured Devices 143 8.2.1 Colour Temperature Tuning 143 8.2.2 Compatibility with Photo-patterning 145 8.2.3 Colour Stability 150 8.3 Summary 154 9 Efficiency Roll-off and Emission Colour of Microstructured OLEDs 155 9.1 Photolithographic Control of the Subunit Dimension 155 9.2 Control of the Emission Colour 156 9.3 Suppression of Efficiency Roll-off in Microscale Devices 157 9.4 Thermal Management in OLEDs 159 9.5 Modelling Impact of Joule Heat on Roll-off Characteristics 162 9.6 Summary 164 10 Conclusions and Outlook 165 10.1 Conclusions 165 10.2 Outlook 167 List of Abbreviations 171 List of Figures 173 List of Tables 177 Acknowledgements 179 Bibliography 181
164

Photostructuration de matériaux nanocomposites à propriétés magnéto-optiques : vers la réalisation de composants pour l'optique intégrée / Photostructuration of nanocomposite materials with magneto-optical properties : towards realization of integrated devices in optical chips

Bidaud, Clémentine 14 November 2018 (has links)
L’objectif principal de ce travail de thèse est de formuler un matériau nanocomposite doté de propriétés magnéto-optiques (MO) et photostructurable pour, in fine, réaliser des dispositifs optiques non-réciproques pouvant être intégrés au sein de puces optiques. Le matériau nanocomposite MO est obtenu en dispersant des nanoparticules magnétiques (NP) de ferrite de cobalt dans une matrice sol-gel d’alcoxydes de silicium et de titane. Les NP confèrent au matériau ses propriétés MO. La formulation du matériau est photostructurable en UV profond (193, 266 nm) sans ajout de photoamorceur et se comporte comme une photo-résine négative. La formulation est flexible en termes de ratio molaire Si/Ti et de dopage en NP pouvant atteindre 20 %vol. La photochimie du matériau en films minces a été étudiée par ellipsométrie spectroscopique, FTIR et spectroscopie UV-visible. Les techniques de photolithographies UV interférométriques et par masques binaires ont permis de réaliser des réseaux périodiques de lignes bien définis et couvrant une large gamme de périodes, de 500 nm à 100 µm. Les propriétés optiques et MO (rotation Faraday) du matériau ont été étudiées. En couches minces, l’indice de réfraction peut être modulé entre 1,4 et 1,7 selon la composition du matériau. Il a été établi que l’ensemble des NP introduites dans le matériau contribuent à la rotation Faraday. Des dispositifs microstructurés ont été réalisés en espace libre et en configuration guidée en se basant sur les dimensionnements opto-géométriques déterminés par des simulations optiques et MO. Leurs caractérisations démontrent l’intérêt de ce matériau et son caractère prometteur pour réaliser des dispositifs intégrés. / The main objective of this PhD work is to formulate a nanocomposite material with magneto-optical (MO) properties which is also photostructurable, in order to ultimately create non-reciprocal optical devices that can be integrated into optical chips. The nanocomposite MO material is obtained by homogenously dispersing magnetic nanoparticles (NP) of cobalt ferrite in a sol-gel matrix based on silicon and titanium alkoxides. NP confer the material its MO properties. The material is photostructurable with deep UV wavelengths (193, 266 nm) without any addition of photoinitiator and behaves like a negative photoresist. The formulation is versatile in terms of Si/Ti molar ratio and NP doping, up to 20 %vol. The photochemistry of this material as thin films has been studied by spectroscopic ellipsometry, FTIR and UV-visible spectroscopy. UV photolithography techniques using interferometry setups and binary masks have achieved well-defined periodic lines patterns over a wide range of periods, from 500 nm to 100 microns. The optical and MO (Faraday rotation) properties of the material were studied. In thin layers, the refractive index can be modulated between 1.4 and 1.7 depending on the Si/Ti material stoichiometry and its NP doping. It has been established that all the NP introduced in the material contribute to the Faraday rotation. Micro-structured devices in free space and in guided configuration have been realized using the opto-geometrical features determined using optical and MO simulations. Their characterizations demonstrate the high interest of this material and clearly show its promising character to realize integrated devices.
165

Growth Techniques and Optical and Electrical Characterization of Quantum Confined Zero-Dimensional and Two-Dimensional Device Structures

Wickramasinghe, Thushan E. January 2019 (has links)
No description available.
166

Development of a Microfluidic Platform for Cell-Cell Communication

Watson, Craig 23 May 2022 (has links)
No description available.
167

Micropatterning Neuronal Networks on Nanofiber Platforms

Malkoc, Veysi 27 August 2013 (has links)
No description available.
168

PIV Measurements of Turbulent Flow in a Rectangular Channel over Superhydrophobic Surfaces with Riblets

Perkins, Richard Mark 01 September 2014 (has links) (PDF)
In this thesis I investigate characteristics of turbulent flow in a channel where one of the walls has riblets, superhydrophobic microribs, or a hybrid surface with traditional riblets built on a superhydrophobic microrib surface. PIV measurements are used to find the velocity profile, the turbulent statistics, and shear stress profile in the rectangular channel with one wall having a structured test surface. Both riblets and superhydrophobic surfaces can each provide a reduction in the wall shear stress in a turbulent channel flow. Characterizing the features of the flow using particle image velocimetry (PIV) is the focus of this research. Superhydrophobicity results from the combination of a hydrophobic coating applied to a surface with microrib structures, resulting in a very low surface energy, such that the fluid does not penetrate in between the structures. The micro-rib structures are aligned in the streamwise flow direction. The riblets are larger than the micro-rib structure by an order of magnitude and protrude into the flow. All the test surfaces were produced on silicon wafers using photolithographic techniques. Pressure in the channel is maintained below the Laplace pressure for all testing, creating sustainable air pockets between the microribs. Velocity profiles, turbulent statistics, shear stress profiles, and friction factors are presented. Measurements were acquired for Reynolds numbers ranging from 4.5x10^3 to 2.0x10^4. Modest drag reductions were observed for the riblet surfaces. Substantial drag increase occurred over the superhydrophobic surfaces. The hybrid surfaces showed the greatest drag reduction. Turbulence production was strongly reduced during riblet and hybrid tests.
169

From Macro to Nano : Electrokinetic Transport and Surface Control

Pardon, Gaspard January 2014 (has links)
Today, the growing and aging population, and the rise of new global threats on human health puts an increasing demand on the healthcare system and calls for preventive actions. To make existing medical treatments more efficient and widely accessible and to prevent the emergence of new threats such as drug-resistant bacteria, improved diagnostic technologies are needed. Potential solutions to address these medical challenges could come from the development of novel lab-on-chip (LoC) for point-of-care (PoC) diagnostics. At the same time, the increasing demand for sustainable energy calls for the development of novel approaches for energy conversion and storage systems (ECS), to which micro- and nanotechnologies could also contribute. This thesis has for objective to contribute to these developments and presents the results of interdisciplinary research at the crossing of three disciplines of physics and engineering: electrokinetic transport in fluids, manufacturing of micro- and nanofluidic systems, and surface control and modification. By combining knowledge from each of these disciplines, novel solutions and functionalities were developed at the macro-, micro- and nanoscale, towards applications in PoC diagnostics and ECS systems. At the macroscale, electrokinetic transport was applied to the development of a novel PoC sampler for the efficient capture of exhaled breath aerosol onto a microfluidic platform. At the microscale, several methods for polymer micromanufacturing and surface modification were developed. Using direct photolithography in off-stoichiometry thiol-ene (OSTE) polymers, a novel manufacturing method for mold-free rapid prototyping of microfluidic devices was developed. An investigation of the photolithography of OSTE polymers revealed that a novel photopatterning mechanism arises from the off-stoichiometric polymer formulation. Using photografting on OSTE surfaces, a novel surface modification method was developed for the photopatterning of the surface energy. Finally, a novel method was developed for single-step microstructuring and micropatterning of surface energy, using a molecular self-alignment process resulting in spontaneous mimicking, in the replica, of the surface energy of the mold. At the nanoscale, several solutions for the study of electrokinetic transport toward selective biofiltration and energy conversion were developed. A novel, comprehensive model was developed for electrostatic gating of the electrokinetic transport in nanofluidics. A novel method for the manufacturing of electrostatically-gated nanofluidic membranes was developed, using atomic layer deposition (ALD) in deep anodic alumina oxide (AAO) nanopores. Finally, a preliminary investigation of the nanopatterning of OSTE polymers was performed for the manufacturing of polymer nanofluidic devices. / <p>QC 20140509</p> / Rappid / NanoGate / Norosensor
170

Etude de la stabilité et de la précision des modèles utilisés dans la correction des effets de proximité optique en photolithographie / Study of the impact of different physical parameters during OPC model creation for 65nm and 45nm technologies

Saied, Mazen 30 September 2011 (has links)
À l’heure actuelle, les modèles photochimiques utilisés dans la correction des effets de proximitéoptique (OPC) en photolithographie sont devenus complexes et moins physiques afin de permettre decapturer rapidement le maximum d’effets optiques et chimiques. La question de la stabilité de tels modèlespurement empiriques est devenue d’actualité. Dans ce mémoire, nous avons étudié la stabilité desmodèles photochimiques actuels en examinant les différentes causes d’instabilité vis-à-vis des paramètresdu procédé. Dans la suite, nous avons développé une méthode perturbative permettant d’évaluer le critèrede la stabilité. L’obtention de modèles simples et stables nous conduit à séparer les effets optiques desautres effets chimiques. De plus, les approximations utilisées dans la modélisation des systèmes optiquesopérant à grande ouverture numérique entraînent des erreurs résiduelles pouvant dégrader la précisionet la stabilité des modèles OPC. Ainsi, nous nous sommes intéressés à étudier les limites de validitéde l’approximation de Kirchhoff, méthode qui, jusqu’à présent, est la plus utilisée dans la modélisationdu champ proche d’un masque. D’autres méthodes semi-rigoureuses, permettant de modéliser les effetstopographiques, ont été également évaluées. Ces méthodes approchées permettent de gagner en précisionmais dégradent le temps de calcul. Nous avons ainsi proposé différentes façons de corriger les effetstopographiques du masque, tout en gardant l’approximation de Kirchhoff dans la modélisation de la partieoptique. Parmi les méthodes proposées, nous exploitons celle permettant de réduire les erreurs liéesaux effets topographiques du masque par l’intermédiaire d’un second modèle empirique. Nous montronsque pour garantir une précision adéquate, il est nécessaire d’augmenter la complexité du modèle en rajoutantdes termes additionnels. Enfin, pour garantir la stabilité numérique du modèle empirique, nousintroduirons une nouvelle méthode approchée hybride rapide et précise, la méthode des multi-niveaux,permettant d’inclure les effets topographiques par décomposition multi-niveaux du masque fin et discuteronsses avantages et ses limites. / At present, common resist models utilized in photolithography to correct for optical proximity effects(OPC) became complex and less physical in order to capture the maximum of optical and chemical effectsin shorter times. The question on the stability of such models, purely empirical, become topical. In thisthesis, we study the stability of existing OPC models by examining the origins of model instability towardsprocess parameters. Thus, we have developed a perturbative method in order to evaluate the stabilitycriterion. However, achieving stable and simple models needs a separation between optical and otherchemical effects. Besides, multiple approximations, widely utilized in the modeling of optical systemsoperating at high numerical aperture, lead to residual errors which can degrade OPC model accuracyand stability. Thus, we were interested to study the limits of validity of the Kirchhoff approximation,a method which, so far, is the most commonly used in mask near-field modeling. Other semi-rigorousmethods for mask topography effect modeling were also evaluated. These approximate methods canimprove the accuracy but degrades the run time. We then suggested different techniques to correct formask topography effects, while keeping the Kirchhoff approximation in the modeling of the optical part.Among them, we showed that errors due to mask topography effects can be partially captured by asecond empirical model. However, in order to ensure a good accuracy, it is necessary to increase themodel complexity by using more additional empirical terms. Finally, in order to achieve a numericalstability of the empirical model, we introduced a new hybrid fast and accurate method, the multi-levelmethod, which allows us to correct for mask topography effects through a multi-level decomposition ofthe thin mask and discussed its advantages and drawbacks.

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