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Nanopatterning of Phase Change Material Ge2SbTe5 towards Novel and Improved Reconfigurable Photonic DevicesBurrow, Joshua A. January 2021 (has links)
No description available.
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Nucleation and Growth, Defect Structure, and Dynamical Behavior of Nanostructured MaterialsHubartt, Bradley C. January 2014 (has links)
No description available.
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Performance enhancement of organic photovoltaic cells through nanostructuring and molecular dopingYu, Shuwen 05 March 2015 (has links)
Die vorliegende Arbeit beschäftigt sich mit der Leistungssteigerung organischer Solarzellen durch Änderung der Geometrie an der Donor-Akzeptor Grenzfläche und dem Einstellen der elektronischen Eigenschaften von Grenzflächen durch molekulares p-Dotieren. Kristalline und gleichmäßige Nanosäulen aus dem organischen Halbleiter Pentazen wurden durch glancing angle deposition (GLAD) hergestellt, die einen ineinandergreifenden Heteroübergang zu Methanofulleren [6,6]-Phenyl-C61-Butansäure Methylester (PCBM) als Akzeptor ermöglichten. Die Kurzschlussspannung der nanosäulenbasierten Solarzellen war signifikant erhöht im Vergleich zu planaren Heteroübergängen zwischen denselben Materialien. Die Leistungssteigerung der Solarzellen konnte maßgebend der vergrößerten Grenzfläche zugewiesen werden, wegen des verringerten Einflusses der kurzen Exciton Diffusionslänge. Molekulares p-Dotieren mit Tetrafluorotetracyanoquinodimethan (F4TCNQ) als Dotand in polyfuranbasierten Solarzellen wurde für verschiede Dotierkonzentrationen untersucht. Ultraviolettphotoelektronenspektroskopie wurde verwendet, um die Veränderungen der Energieniveaus mit zunehmender Dotierkonzentration zu analysieren, welche zu einer Vergrößerung der 0,2 V Kurzschlussspannung auf bis zu 0,4 V führte. Nach Kombination dieser Beobachtung mit Ergebnissen an dotierten Polymerfilmen, insbesondere bezüglich deren Morphologie und Absorptionsverhalten, wurde vorgeschlagen, dass ein resultierender Dipol an der Donor-Akzeptorgrenzfläche präsent ist. Zusammenfassend zeigt die vorliegende Arbeit das Potential sowohl der GLAD Technik als auch des molekularen, elektrischen Dotierens für die Leistungsverbesserung organischer Solarzellen. / The present work mainly focuses on improving the performance of OPVCs by tailoring the donor-acceptor interface geometry and by tuning the electrical properties of interfaces with p-type molecular doping. Crystalline and uniform nanocolumns of pentacene (PEN) and diindenoperylene (DIP) were fabricated by glancing angle deposition (GLAD), forming an interdigitated donor/acceptor heterojunction with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and/or fullerene as the electron acceptor. The short circuit current of nanocolumn-based OPVCs increased significantly compared to planar heterojunction OPVCs made from the same materials. The performance improvement of OPVCs had been verified to be contributed decisively by the donor-acceptor interface area enlargement because of reduced impact of short exciton diffusion length in organic materials. P-type molecular doping as applied in polyfuran (PF) based OPVCs was investigated by using tetrafluorotetracyanoquinodimethane (F4-TCNQ) as the dopant for various doping ratios. Ultraviolet photoelectron spectroscopy (UPS) was applied to analyze the energy level shift with increasing doping ratio leading to the enlargement of the open circuit voltage in OPVCs, from 0.2 V to close to 0.4 V. Combining this observation with the results of doped polymer films, their morphology and absorption behavior, a net dipole pointing towards the donor material at the donor-acceptor interface of OPVCs is proposed. Overall, this work demonstrates the potential of both the GLAD technique and molecular electrical doping for improving the performance of OPVCs.
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The Influence of Organic Coatings on Atmospheric Processes at the Air-Water InterfaceHenderson, Elyse Ann 18 March 2014 (has links)
The air-water interface is abundant in the environment, thus it is an important proxy for atmospheric processes such as the uptake and transfer of molecules, heterogeneous reactions, photochemistry, and cloud condensation. This thesis aims to elucidate the role of semi-soluble and insoluble organic coatings on atmospheric processes at the air-water interface. Using glancing-angle LIF it was found that monolayer coatings of 1-octanol and of octanoic acid have opposing effects on the ozonation rate of pyrene at the air-water interface. LIF was also coupled with a Profile Analysis Tensiometer (PAT-1) to measure the effect of stearic acid coating compression on the uptake of HCl to a water droplet. Due to preliminary issues with this novel technique, no significant uptake suppression was observed. The oxidation of benzene by OH radical was also explored briefly, as were the photophysics of photosensitizers and the angle dependence of Raman signal from a D2O pendent droplet.
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The Influence of Organic Coatings on Atmospheric Processes at the Air-Water InterfaceHenderson, Elyse Ann 18 March 2014 (has links)
The air-water interface is abundant in the environment, thus it is an important proxy for atmospheric processes such as the uptake and transfer of molecules, heterogeneous reactions, photochemistry, and cloud condensation. This thesis aims to elucidate the role of semi-soluble and insoluble organic coatings on atmospheric processes at the air-water interface. Using glancing-angle LIF it was found that monolayer coatings of 1-octanol and of octanoic acid have opposing effects on the ozonation rate of pyrene at the air-water interface. LIF was also coupled with a Profile Analysis Tensiometer (PAT-1) to measure the effect of stearic acid coating compression on the uptake of HCl to a water droplet. Due to preliminary issues with this novel technique, no significant uptake suppression was observed. The oxidation of benzene by OH radical was also explored briefly, as were the photophysics of photosensitizers and the angle dependence of Raman signal from a D2O pendent droplet.
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Ultraviolet stabilization and performance enhancement of nanostructured humidity sensorsSmetaniuk, Daniel Unknown Date
No description available.
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Příprava nanostrukturovaných a nanokompozitních vrstev s matricí plazmového polymeru / Preparation of nanostructured and nanocomposite thin films with plasma polymer matrixSolař, Pavel January 2014 (has links)
Title: Preparation of nanostructured and nanocomposite thin films with plasma polymer matrix Author: Pavel Solař Department: Department of Macromolecular Physics, MFF, UK Supervisor of the doctoral thesis Prof. RNDr. Hynek Biederman, DrSc., Department of Macromolecular Physics, Faculty of Mathematics and Physics, Charles University in Prague Abstract: This thesis is devoted to study of nanostructured thin films implementing metal and plasma polymer particles and columns. Process of formation of particles from various materials has been studied. The particles size, shape and chemical composition has been characterized relative to the deposition conditions. Transport of metal and plasma polymer particles inside the particle source and from the particle source to substrate has been investigated. The particles were used in composite films especially to produce films with controlled roughness e.g. for investigation of influence of roughness on adhesion of cells. Preparation of columnar films by Glancing Angle Deposition has been studied and the particles have been used as seeds for the columnar growth. Keywords: Nanoparticles, Glancing Angle Deposition, plasma polymer, composite thin film
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Oblique Angle Deposition of Thin Films – Theory, Modelling, and ApplicationGrüner, Christoph 24 July 2019 (has links)
With the aim to gain a deeper understanding of the role of the angle of incidence in physical vapor deposition, experimental, and computer-based studies were conducted. Electron beam evaporation and ion beam sputtering were used as deposition methods. The materials germanium, silicon, and molybdenum were deposited at different incidence angle, different temperatures and varied residual gas atmospheres. Established models could not be used to adequately explain the obtained relations between morphological parameters, as the tilt angle, with the incidence angle. To investigate the interplay of self-shadowing and competitive growth, an on-lattice simulation was developed. Care was taken to avoid any artificial anisotropy. Comparison with an, additionally developed, off-lattice simulation was used to verify this. Based on the made observations, an analytical model was deduced that combines the material properties and the deposition conditions into a single parameter. The predictions of this model were verified for the experimental observations, the results of the computer simulations, and on literature data. In the last part of the thesis, methods are shown that facilitate to modify the properties of the obliquely deposited thin films to fit requirements of various applications. This includes in situ doping of silicon nanostructures, creation of core-shell structures, as well as biochemical surface functionalization of silver nanostructures. On the example of the latter, various bio-sensing applications are presented.:1 MOTIVATION 7
2 BASIC CONCEPTS 9
2.1 Physical vapor deposition (PVD) 9
2.2 Deposition at oblique angles 14
2.3 Controlling the thin film morphology 16
3 EXPERIMENTAL METHODS 19
3.1 Sample preparation 19
3.2 Characterization techniques 32
4 EXPERIMENTAL RESULTS 37
4.1 Columnar structure and evolutionary selection 37
4.2 Tilt angles and density 42
4.3 Fan angles 45
4.4 Relevance of beam divergence 47
4.5 Summary 50
5 SIMULATION 53
5.1 Introduction 53
5.2 Off-lattice approach 54
5.3 On-lattice approach 59
5.4 Further applications of the on-lattice simulation 64
5.5 Other aspects 72
5.6 Summary 76
6 OBLIQUE ANGLE DEPOSITION MODEL 77
6.1 Semi-Empirical models 77
6.2 Tanto’s fan model 78
6.3 Development of the Competition Model 80
6.4 Verification of the model 84
6.5 Summary 89
7 FILM OPTIMIZATION FOR APPLICATIONS 91
7.1 Boron doped Si nanostructures 91
7.2 Surface functionalization for biosensors 95
7.3 Core-shell structures by pulsed electrodeposition 101
7.4 Summary 105
8 SUMMARY 107
9 BIBLIOGRAPHY 109
10 LIST OF ABBREVIATIONS 121
11 ACKNOWLEDGEMENTS 123
APPENDIX 125
PUBLICATION LIST 131
SELBSTSTÄNDIGKEITSERKLÄRUNG 133 / Mit dem Ziel ein besseres Verständnis des Einflusses des Einfallswinkels in der physikalischen Gasphasenabscheidung zu erreichen, wurden experimentell realisierte und am Computer simulierte Dünnschichten untersucht. Als Abscheidetechniken kamen sowohl Elektronenstrahl-Verdampfen als auch Ionenstrahl-Zerstäubung zum Einsatz. Es wurden die Materialien Germanium, Silicium und Molybdän verwendet, die bei verschiedenen Einfallswinkeln, verschiedenen Substrattemperaturen und variiertem Restgas abgeschieden wurden. Die beobachteten Zusammenhänge, von bspw. kolumnarer Verkippung und Einfallswinkel, konnten nicht mit den etablierten Modellen in Einklang gebracht werden. Um das genaue Zusammenspiel von Abschattung und Konkurrenz-Wachstum zu verstehen, wurde eine „on-lattice“ Computersimulation entwickelt, mit dem besonderen Augenmerk auf die Vermeidung von gitterbasierten Anisotropien. Dies wurde durch Vergleich mit einer, ebenfalls entwickelten, „off-lattice“ Simulation sichergestellt. Ausgehend von den beobachteten Effekten konnte ein analytisches Modell entwickelt werden, welches die Materialeigenschaften und Abscheidebedingungen in einen einzigen Parameter vereint. Die Vorhersagen des Modells wurden an den hergestellten Schichten, den Computersimulationen und an Literaturdaten verifiziert. Abschließend werden Methoden aufgezeigt, die schräg abgeschiedenen nanostrukturierten Schichten verschiedenen Anwendungen anzupassen. Dies umfasst die in situ Dotierung von Siliciumnanostrukturen, die Erzeugung von Kern-Schale-Strukturen, sowie die biochemische Oberflächenfunktionalisierung von Silbernanostrukturen. Am Beispiel der letztgenannten werden verschiedene Anwendungen in der Biosensorik detaillierter vorgestellt.:1 MOTIVATION 7
2 BASIC CONCEPTS 9
2.1 Physical vapor deposition (PVD) 9
2.2 Deposition at oblique angles 14
2.3 Controlling the thin film morphology 16
3 EXPERIMENTAL METHODS 19
3.1 Sample preparation 19
3.2 Characterization techniques 32
4 EXPERIMENTAL RESULTS 37
4.1 Columnar structure and evolutionary selection 37
4.2 Tilt angles and density 42
4.3 Fan angles 45
4.4 Relevance of beam divergence 47
4.5 Summary 50
5 SIMULATION 53
5.1 Introduction 53
5.2 Off-lattice approach 54
5.3 On-lattice approach 59
5.4 Further applications of the on-lattice simulation 64
5.5 Other aspects 72
5.6 Summary 76
6 OBLIQUE ANGLE DEPOSITION MODEL 77
6.1 Semi-Empirical models 77
6.2 Tanto’s fan model 78
6.3 Development of the Competition Model 80
6.4 Verification of the model 84
6.5 Summary 89
7 FILM OPTIMIZATION FOR APPLICATIONS 91
7.1 Boron doped Si nanostructures 91
7.2 Surface functionalization for biosensors 95
7.3 Core-shell structures by pulsed electrodeposition 101
7.4 Summary 105
8 SUMMARY 107
9 BIBLIOGRAPHY 109
10 LIST OF ABBREVIATIONS 121
11 ACKNOWLEDGEMENTS 123
APPENDIX 125
PUBLICATION LIST 131
SELBSTSTÄNDIGKEITSERKLÄRUNG 133
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Experimental Investigation on Mechanical Properties of Nanospring Thin Films Fabricated by Glancing Angle Deposition Technique / 斜め蒸着法で作製したナノスプリング薄膜の機械特性評価に関する研究Shaoguang, Chen 23 March 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20331号 / 工博第4268号 / 新制||工||1661(附属図書館) / 京都大学大学院工学研究科機械理工学専攻 / (主査)教授 北村 隆行, 教授 北條 正樹, 教授 西脇 眞二 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
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Optical and Microstructural Properties of Sputtered Thin Films for Photovoltaic ApplicationsAdhikari, Dipendra January 2019 (has links)
No description available.
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