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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.
321

Processing and Properties of Encapsulated van der Waals Materials at Elevated Temperature

Hua, Xiang January 2022 (has links)
Since the first successful isolation and subsequent characterization of graphene, the interest in two dimensional (2-D) materials has expanded exponentially. Despite the dozens of graphene-like van der Waals materials that have been found and their interesting properties, a significant obstacle in realizing their promise is their instability especially for monolayer and thin layers at elevated temperature. To overcome the obstacle of passivating the 2-D materials and study their properties at elevated temperature, we take advantage of the potential improvements afforded by assembling heterostructures by stacking the atomic thick 2-D materials together hexagonal boron nitride (ℎ-BN) which possess high chemical stability and thermal stability. In this dissertation, several experiments are described in detail in which we utilized h-BN encapsulation to passivate atomically-thin transition metal dichalcogenide and studied their properties at elevated temperature. In the first project we demonstrated that chemical vapor deposition (CVD)-grown flakes of high-quality monolayers of WS₂ can be stabilized at elevated temperatures by encapsulation with only top ℎ-BN layers in the presence of ambient air, N₂ or forming gas. The best passivation occurs for ℎ-BN covered samples with flowing N₂. In the second project, we demonstrated that encapsulating monolayer MoSe₂ and WS₂ with top and bottom ℎ-BN can improve their thermal stability at high temperature and increase their photoluminescence (PL). The increased PL likely occurs because impurities are laterally expelled from the TMD stack during heating. In the third project, we demonstrated the passivation of different modes of ℎ-BN encapsulation on thin layer FeSe sample by using temperature dependent Raman scattering. The complete encapsulation showed the best protection of thin layer FeSe. Finally, we utilized the temperature dependence of the Raman mode of thin-layer FeSe with complete encapsulation and applied a noncontact method to measure the thermal conductivity of the thin-layer FeSe.
322

Exploration of the Cold-Wall CVD Synthesis of Monolayer MoS2 and WS2

January 2019 (has links)
abstract: A highly uniform and repeatable method for synthesizing the single-layer transition metal dichalcogenides (TMDs) molybdenum disulfide, MoS2, and tungsten disulfide, WS2, was developed. This method employed chemical vapor deposition (CVD) of precursors in a custom built cold-wall reaction chamber designed to allow independent control over the growth parameters. Iterations of this reaction chamber were employed to overcome limitations to the growth method. First, molybdenum trioxide, MoO3, and S were co-evaporated from alumina coated W baskets to grow MoS2 on SiO2/Si substrates. Using this method, films were found to have repeatable coverage, but unrepeatable morphology. Second, the reaction chamber was modified to include a pair of custom bubbler delivery systems to transport diethyl sulfide (DES) and molybdenum hexacarbonyl (MHC) to the substrate as a S and Mo precursors. Third, tungsten hexacarbonyl (WHC) replaced MHC as a transition metal precursor for the synthesis of WS2 on Al2O3, substrates. This method proved repeatable in both coverage and morphology allowing the investigation of the effect of varying the flow of Ar, varying the substrate temperature and varying the flux of DES to the sample. Increasing each of these parameters was found to decrease the nucleation density on the sample and, with the exception of the Ar flow, induce multi-layer feature growth. This combination of precursors was also used to investigate the reported improvement in feature morphology when NaCl is placed upstream of the substrate. This was found to have no effect on experiments in the configurations used. A final effort was made to adequately increase the feature size by switching from DES to hydrogen sulfide, H2S, as a source of S. Using H2S and WHC to grow WS2 films on Al2O3, it was found that increasing the substrate temperature and increasing the H2S flow both decrease nucleation density. Increasing the H2S flow induced bi-layer growth. Ripening of synthesized WS2 crystals was demonstrated to occur when the sample was annealed, post-growth, in an Ar, H2, and H2S flow. Finally, it was verified that the final H2S and WHC growth method yielded repeatability and uniformity matching, or improving upon, the other methods and precursors investigated. / Dissertation/Thesis / Doctoral Dissertation Physics 2019
323

Crystalline properties of gallium oxide thin films epitaxially grown by mist chemical vapor deposition / ミスト化学気相法によるエピタキシャル成長酸化ガリウム薄膜の結晶特性に関する研究

Lee, Sam-Dong 23 March 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19721号 / 工博第4176号 / 新制||工||1644(附属図書館) / 32757 / 京都大学大学院工学研究科電子工学専攻 / (主査)教授 藤田 静雄, 教授 髙岡 義寛, 准教授 須田 淳 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
324

Optoelectronic Properties of Wide Band Gap Semiconductors

Saadatkia, Pooneh 06 August 2019 (has links)
No description available.
325

Characterization of Titanium Deposition on Nickel Wires using In-situ X-ray Tomography

Bhattacharjee, Arun 06 June 2023 (has links)
No description available.
326

Vapor-Liquid-Solid Growth of Semiconductor SiC Nanowires for Electronics applications

Thirumalai, Rooban Venkatesh K G 17 August 2013 (has links)
While investigations of semiconductor nanowires (NWs) has a long history, a significant progress is yet to be made in silicon carbide (SiC) NW technologies before they are ready to be utilized in electronic applications. In this dissertation work, SiC NW polytype control, NW axis orientation with respect to the growth substrate and other issues of potential technological importance are investigated. A new method for growing SiC NWs by vapor-liquid-solid mechanism was developed. The method is based on an in-situ vapor phase delivery of a metal catalyst to the growth surface during chemical vapor deposition. This approach is an alternative to the existing seeded catalyst method based on ex-situ catalyst deposition on the target substrate. The new SiC NW growth method provided an improved control of the NW density. It was established that the NW density is influenced by the distance from the catalyst source to the substrate and is affected by both the gas flow rate and the catalyst diffusion in the gas phase. An important convenience of the new method is that it yields NW growth on the horizontal substrate surfaces as well as on titled and vertical sidewalls of 4H-SiC mesas. This feature facilitates investigation of the NW growth trends on SiC substrate surfaces having different crystallographic orientations simultaneously, which is very promising for future NW device applications. It was established that only certain orientations of the NW axes were allowed when growing on a SiC substrate. The allowed orientations of NWs of a particular polytype were determined by the crystallographic orientation of the substrate. This substrate-dependent (i.e., epitaxial) growth resulted in growth of 3C-SiC NWs in total six allowed crystallographic orientations with respect to the 4H-SiC substrate. This NW axis alignment offers an opportunity to achieve a limited number of NW axis directions depending on the surface orientation of the substrate. The ease of controlling the NW density enabled by the vapor-phase catalyst delivery approach developed in this work, combined with the newly obtained knowledge about how to grow unidirectional (wellaligned) NW arrays, offer new opportunities for developing novel SiC NW electronic and photonic devices.
327

Carbon Nanotube and Nanoparticle Materials for Electromagnetics Applications

Ruff, Bradley M. 10 October 2013 (has links)
No description available.
328

Fabrication of high yield horizontally aligned single wall carbon nanotubes for molecular electronics

Ibrahim, Imad 25 April 2013 (has links)
The extraordinary properties of the single wall carbon nanotubes (SWCNTs) have stimulated an enormous amount of research towards the realization of SWCNT-based products for different applications ranging form nanocomposites to nanoelectronics. Their high charge mobility, exceedingly good current-carrying capacities and ability to be either semiconducting or metallic render them ideal building blocks for nanoelectronics. For nanoelectronic applications, either individual or parallel aligned SWCNTs are advantageous. Moreover, closely packed arrays of parallel SWCNTs are required in order to sustain the relatively large currents found in high frequency devices. Two key areas still require further development before the realization of large-scale nanoelectronics. They are the reproducible control of the nanotubes spatial position/orientation and chiral management. In terms of nanotube orientation, different techniques have been demonstrated for the fabrication of horizontally aligned SWCNTs with either post synthesis routes (e.g. dielectrophoresis and Langmuir-Blodgett approach) or direct growth (e.g. chemical vapor deposition (CVD)). The low temperature of the production process, allowing the formation of aligned nanotubes on pretty much any substrate, is the main advantage of the post synthesis routes, while the poor levels of reproducibility and spatial control, and the limited quality of the aligned tubes due to the inherently required process steps are limitations. The simplicity, up-scalability, along with the reproducible growth of clean high quality SWCNTs with well-controlled spatial, orientation and length, make CVD the most promising for producing dense horizontally well-aligned SWCNTs. These CVD techniques suffer some drawbacks, namely, that because they are synthesized using catalyst particles (metals or non-metals) the catalyst material can contaminate the tubes and affect their intrinsic properties. Thus, the catalyst-free synthesis of aligned SWNT is very desirable. This thesis comprises detailed and systematic experimental investigations in to the fabrication of horizontally aligned SWCNTs using both post growth (Dielectrophoresis) and direct growth (CVD) methods. Both catalyst-assisted and catalyst-free SWCNTs are synthesized by CVD. While metallic nanoparticles nucleate and grow SWCNTs, opened and activated fullerene structures are used for all carbon catalyst-free growth of single wall and double wall carbon nanotubes. The systematic studies allow for a detailed understanding of the growth mechanisms of catalyst and catalyst-free grown SWCNTs to be elucidated. The data significantly advances our understanding of horizontally aligned carbon nanotubes by both post synthesis alignment as well as directly as-synthesized routes. Indeed, the knowledge enables such tubes to be grown in high yield and with a high degree of special control. It is shown, for the first time, how one can grow horizontally aligned carbon nanotubes in crossbar configurations in a single step and with bespoke crossing angles. In addition, the transport properties of the aligned tubes at room temperature are also investigated through the fabrication of devices based on these tubes.:Introduction ……………………………………………………………….…………… 11 1 Carbon nanotubes basics ……………………………………………………. 15 1.1 sp2 hybridization …………………………………………………….……… 16 1.2 Graphene basics ………………………………………………………...… 16 1.3 Single wall carbon nanotubes Basics …………………………… 18 1.4 Synthesis of single wall carbon nanotubes ………………… 24 1.4.1 Arc discharge ………………………………………………… 24 1.4.2 Laser ablation ……………………………………………… 24 1.4.3 Chemical vapor deposition …………………………… 25 1.4.4 The as-produced carbon nanotubes …………… 25 1.5 Potential applications of single wall carbon nanotubes 26 1.6 Challenges face single wall carbon nanotubes ………… 27 2 Horizontally aligned single wall carbon nanotubes: a review of fabrication and characterization ………………………………………………… 29 2.1 Introduction …………………………………………...………………………………………… 29 2.2 The requisites of horizontally aligned single wall carbon nanotubes 31 2.3 Characterization of Horizontally aligned single wall carbon nanotubes 32 2.3.1 Electron microscopy …………………………………………………………… 32 2.3.2 Scanning probe microscopy ……………………………………...…………… 34 2.3.3 Spectroscopy ……………………………………………………………………… 35 2.4 Fabrication of horizontally aligned single wall carbon nanotubes ……… 36 2.4.1 Dielectrophoresis (Growth-then-place) …………………….…………… 36 2.4.2 Chemical vapor deposition (Growth-in-place) ………...…………… 40 2.5 Transistor performance from horizontally aligned single wall carbon nanotubes ……… 67 2.5.1 Field effect transistor ……………….…………...………………………….…… 67 2.5.2 Thin film transistor …………………………….…...…………………….……… 68 3 Dielelectrophoretic deposition of single wall carbon nanotubes 69 3.1 Deposition of single wall carbon nanotubes in between metallic electrodes ………………… 69 3.1.1 Dispersion of single wall carbon nanotubes ………………………… 69 3.1.2 Dielectrophoretic alignment of single wall carbon nanotubes 70 3.2 CNTFET topographical characterization …………..………………………..……… 70 3.3 Dielectrophoresis advantages and drawbacks ………………………….....……… 72 4 Growth of catalyst-assisted horizontally aligned single wall carbon nanotubes …..………..... 75 4.1 Experimental procedure ….………………………………………………………...……… 76 4.1.1 ST-cut quartz substrates preparation ……………………….....……… 76 4.1.2 Catalyst solutions preparation ……………………………........……… 76 4.1.3 Growth of single wall carbon nanotubes ……………………………… 77 4.1.4 Single wall carbon nanotubes transfer into silicon substrates 78 4.2 Substrate thermal treatment ………………………………………………..........……… 79 4.3 Formed catalyst nanoparticles ………………………………………………...……… 82 4.4 As-grown single wall carbon nanotubes ………………...……………..…………… 84 4.5 Transferred single wall carbon nanotubes ………………...………….……...…… 91 4.6 Chapter summary ………………………………………………...…………………………… 92 5 Growth of catalyst-free horizontally aligned single wall carbon nanotubes … 93 5.1 Experimental procedure ………………………………………………………………….… 94 5.1.1 Different fullerene-based structure ……………………...……………… 94 5.1.2 Pre-treatment of fullerene structures …………………………...…….. 95 5.1.3 Growth of catalyst-free single wall carbon nanotubes ………… 96 5.2 Different fullerene structures nucleate the growth of single wall carbon nanotubes …… 97 5.3 C60 nucleated aligned single wall carbon nanotubes .……………...………… 98 5.3.1 Orientation of the as-grown nanotubes …………………………..… 98 5.3.2 Yield of the grown nanotubes ……………………………………………… 99 5.3.3 Activated sp2 caps ……………………………………………………...……….… 103 5.3.4 Type of the grown nanotubes …………………………………...………… 106 5.3.5 Growth mechanism of carbon nanotubes nucleated from fullerene … 109 6 Electrical characterization of the aligned single wall carbon nanotubes ……… 113 6.1 Device fabrication …………………………………………………………………..…………… 114 6.1.1 FET fabrication over the dielectrophoretic deposited carbon nanotubes … 114 6.1.2 Fabrication of the CVD grown nanotubes based device …………114 6.2 Electrical characterization of dielectrophoretic deposited single wall carbon nanotubes 115 6.2.1 I-V characteristics of the dielectrophoretic deposited nanotubes 115 6.2.2 Defect detection ………………………………………………………………..…… 117 6.3 Electrical characterization of the CVD grown nanotubes ……………………… 120 6.3.1 IV-Characteristics of the metal-assisted single wall carbon nanotubes ……… 120 6.3.2 Electrical behaviour of the catalyst-free single wall carbon nanotubes …………122 7 Conclusions and outlook ……………..……………………..………………………… 125 Appendix ……..……………………………………..………………………….……………. 129 Bibliography …...…………………………………..………………………….……………. 133 List of figures ….…………………………………..………………………….……………. 143 Glossary …………..…………………………………..………………………….……………. 147 Publications ………………………………………..………………………….……………. 149 Curriculum vitae ……………………………………..………………..…………………. 153 Acknowledgment ……..…………………………………..…..…………………………. 155 Declaration …………………………………………………..…..…………………………. 157 / Die außergewöhnlichen Eigenschaften von einwandigen Kohlenstoffnanoröhren (engl. single wall carbon nanotubes, SWCNTs) haben bemerkenswerte Forschungsaktivitäten zur Verwirklichung von auf SWCNTs basierenden Anwendungen für verschiedene Bereiche, die von Nanokompositen bis hin zur Nanoelektronik reichen, stimuliert. Ihre hohe Ladungsträgermobilität und die außerordentlichen hohen Ladungsdichten, die in SWCNTs erreicht werden können sowie ihre Eigenschaft, entweder halbleitend oder metallisch zu sein, machen sie zu idealen Konstituenten von nanoelektronischen Schaltkreisen. Für Anwendungen in der Nanoelektronik sind entweder einzelne oder parallel angeordnete SWCNTs vorteilhaft. Darüber hinaus sind dicht gepackte Anordnungen von SWCNTs erforderlich, um die relativ hohen Ströme in Hochfrequenzbauelementen zu transportieren. Für eine erfolgreiche Realisierung von großskaligen nanoelektronischen Bauteilen, die auf SWCNTs basieren, sind noch zwei enorm wichtige Kernprobleme zu lösen, die weitere Forschungsanstrengungen erfordern: die reproduzierbare und verlässliche Kontrolle der räumlichen Positionierung und Orientierung der Nanoröhren sowie die Kontrolle der Chiralität der einzelnen SWCNTs. Hinsichtlich der Orientierung der Nanoröhren kann die horizontal parallele Ausrichtung von SWCNTs mit verschiedenen Techniken erreicht werden. Diese setzen entweder nach dem eigentlichen Wachstum der Röhren ein (Post-Synthese-Methoden wie z.B. Dielektrophorese oder Langmuir-Blodgett-Techniken) oder erreichen direkt während des Wachstums (z.B. durch Chemical-Vapor-Deposition-Methoden (CVD)) die parallele Anordnung. Durch die niedrigen Prozesstemperaturen, die während des Herstellungsprozesses erforderlich sind, erlauben die nach der eigentlichen Synthese stattfindenden Ausrichtungsmethoden die parallele Anordnung von Nanoröhren auf nahezu jedem Substrat, jedoch stellen die geringe Reproduzierbarkeit dieser Prozesse, die schwierige Kontrollierbarkeit der räumlichen Anordnung und die limitierte Qualität der ausgerichteten Röhren aufgrund der erforderlichen Prozessschritte natürliche Beschränkungen dieser Techniken dar. Die einfache Durchführung und ihre Skalierbarkeit, zusammen mit dem reproduzierbaren Wachstum qualitativ sehr hochwertiger SWCNTs mit hoher Kontrolle von räumlicher Anordnung, Orientierung und Länge machen die CVD-Methode zur erfolgversprechendsten Technik für die Herstellung von dichtgepackten hochparallelen horizontalen Anordnungen von SWCNTs. Diese CVD-Ansätze weisen jedoch auch einige Nachteile auf, die in den bei der Synthese verwendeten Katalysatorpartikeln (metallisch oder nicht-metallisch) begründet liegen, da das Katalysatormaterial die Röhren kontaminieren und dadurch ihre intrinsischen Eigenschaften beeinflussen kann. Daher ist eine katalysatorfreie Synthesemethode für ausgerichtete SWCNTs ein höchst erstrebenswertes Ziel. Die vorliegende Arbeit beschreibt detaillierte und systematische experimentelle Untersuchungen zur Herstellung von horizontalen, parallel ausgerichteten Anordnungen von SWCNTs unter Verwendung von Methoden, die sowohl nach dem eigentlichen Wachstum der Nanoröhren (Dielektrophorese) als auch während des Wachstums ansetzen (CVD). Bei den CVD-Methoden werden sowohl solche, die auf der Verwendung von Katalysatoren basieren, als auch katalysatorfreie Techniken verwendet. Während metallische Nanopartikel den Ausgangspunkt für das Wachstum von SWCNTs darstellen, werden geöffnete und aktivierte Fullerenstrukturen verwendet, um das katalysatorfreie Wachstum von reinen ein- oder mehrwandigen Nanoröhren zu erreichen. Die systematischen Untersuchungen ermöglichen ein tiefgehendes Verständnis der Wachstumsmechanismen von SWCNTs, die unter Verwendung von Katalysatoren oder katalysatorfrei erzeugt synthetisiert wurden. Die erzielten Ergebnisse erhöhen in einem hohen Maß das Verständnis der Herstellung von horizontal parallel angeordneten Nanoröhren, die durch Post-Synthese-Methoden oder direkt während des Wachstumsprozesses ausgerichtet wurden. Die erzielten Einsichten erlauben die Herstellung solcher Strukturen mit hoher Ausbeute und mit einem hohen Maß an räumlicher Kontrolle der Anordnung. Zum ersten Male kann ein Verfahren präsentiert werden, mit dem horizontal parallel angeordnete Nanoröhren in gekreuzten Strukturen mit wohldefinierten Kreuzungswinkeln hergestellt werden können. Zusätzlich werden die Transporteigenschaften von parallel ausgerichteten Nanoröhren bei Raumtemperatur, durch die Herstellung von auf den dargestellten Strukturen basierenden Bauelementen, untersucht.:Introduction ……………………………………………………………….…………… 11 1 Carbon nanotubes basics ……………………………………………………. 15 1.1 sp2 hybridization …………………………………………………….……… 16 1.2 Graphene basics ………………………………………………………...… 16 1.3 Single wall carbon nanotubes Basics …………………………… 18 1.4 Synthesis of single wall carbon nanotubes ………………… 24 1.4.1 Arc discharge ………………………………………………… 24 1.4.2 Laser ablation ……………………………………………… 24 1.4.3 Chemical vapor deposition …………………………… 25 1.4.4 The as-produced carbon nanotubes …………… 25 1.5 Potential applications of single wall carbon nanotubes 26 1.6 Challenges face single wall carbon nanotubes ………… 27 2 Horizontally aligned single wall carbon nanotubes: a review of fabrication and characterization ………………………………………………… 29 2.1 Introduction …………………………………………...………………………………………… 29 2.2 The requisites of horizontally aligned single wall carbon nanotubes 31 2.3 Characterization of Horizontally aligned single wall carbon nanotubes 32 2.3.1 Electron microscopy …………………………………………………………… 32 2.3.2 Scanning probe microscopy ……………………………………...…………… 34 2.3.3 Spectroscopy ……………………………………………………………………… 35 2.4 Fabrication of horizontally aligned single wall carbon nanotubes ……… 36 2.4.1 Dielectrophoresis (Growth-then-place) …………………….…………… 36 2.4.2 Chemical vapor deposition (Growth-in-place) ………...…………… 40 2.5 Transistor performance from horizontally aligned single wall carbon nanotubes ……… 67 2.5.1 Field effect transistor ……………….…………...………………………….…… 67 2.5.2 Thin film transistor …………………………….…...…………………….……… 68 3 Dielelectrophoretic deposition of single wall carbon nanotubes 69 3.1 Deposition of single wall carbon nanotubes in between metallic electrodes ………………… 69 3.1.1 Dispersion of single wall carbon nanotubes ………………………… 69 3.1.2 Dielectrophoretic alignment of single wall carbon nanotubes 70 3.2 CNTFET topographical characterization …………..………………………..……… 70 3.3 Dielectrophoresis advantages and drawbacks ………………………….....……… 72 4 Growth of catalyst-assisted horizontally aligned single wall carbon nanotubes …..………..... 75 4.1 Experimental procedure ….………………………………………………………...……… 76 4.1.1 ST-cut quartz substrates preparation ……………………….....……… 76 4.1.2 Catalyst solutions preparation ……………………………........……… 76 4.1.3 Growth of single wall carbon nanotubes ……………………………… 77 4.1.4 Single wall carbon nanotubes transfer into silicon substrates 78 4.2 Substrate thermal treatment ………………………………………………..........……… 79 4.3 Formed catalyst nanoparticles ………………………………………………...……… 82 4.4 As-grown single wall carbon nanotubes ………………...……………..…………… 84 4.5 Transferred single wall carbon nanotubes ………………...………….……...…… 91 4.6 Chapter summary ………………………………………………...…………………………… 92 5 Growth of catalyst-free horizontally aligned single wall carbon nanotubes … 93 5.1 Experimental procedure ………………………………………………………………….… 94 5.1.1 Different fullerene-based structure ……………………...……………… 94 5.1.2 Pre-treatment of fullerene structures …………………………...…….. 95 5.1.3 Growth of catalyst-free single wall carbon nanotubes ………… 96 5.2 Different fullerene structures nucleate the growth of single wall carbon nanotubes …… 97 5.3 C60 nucleated aligned single wall carbon nanotubes .……………...………… 98 5.3.1 Orientation of the as-grown nanotubes …………………………..… 98 5.3.2 Yield of the grown nanotubes ……………………………………………… 99 5.3.3 Activated sp2 caps ……………………………………………………...……….… 103 5.3.4 Type of the grown nanotubes …………………………………...………… 106 5.3.5 Growth mechanism of carbon nanotubes nucleated from fullerene … 109 6 Electrical characterization of the aligned single wall carbon nanotubes ……… 113 6.1 Device fabrication …………………………………………………………………..…………… 114 6.1.1 FET fabrication over the dielectrophoretic deposited carbon nanotubes … 114 6.1.2 Fabrication of the CVD grown nanotubes based device …………114 6.2 Electrical characterization of dielectrophoretic deposited single wall carbon nanotubes 115 6.2.1 I-V characteristics of the dielectrophoretic deposited nanotubes 115 6.2.2 Defect detection ………………………………………………………………..…… 117 6.3 Electrical characterization of the CVD grown nanotubes ……………………… 120 6.3.1 IV-Characteristics of the metal-assisted single wall carbon nanotubes ……… 120 6.3.2 Electrical behaviour of the catalyst-free single wall carbon nanotubes …………122 7 Conclusions and outlook ……………..……………………..………………………… 125 Appendix ……..……………………………………..………………………….……………. 129 Bibliography …...…………………………………..………………………….……………. 133 List of figures ….…………………………………..………………………….……………. 143 Glossary …………..…………………………………..………………………….……………. 147 Publications ………………………………………..………………………….……………. 149 Curriculum vitae ……………………………………..………………..…………………. 153 Acknowledgment ……..…………………………………..…..…………………………. 155 Declaration …………………………………………………..…..…………………………. 157
329

Atmospheric Pressure Chemical Vapor Deposition of Functional Oxide Materials for Crystalline Silicon Solar Cells

Davis, Kristopher 01 January 2015 (has links)
Functional oxides are versatile materials that can simultaneously enable efficiency gains and cost reductions in crystalline silicon (c-Si) solar cells. In this work, the deposition of functional oxide materials using atmospheric pressure chemical vapor deposition (APCVD) and the integration of these materials into c-Si solar cells are explored. Specifically, thin oxide films and multi-layer film stacks are utilized for the following purposes: (1) to minimize front surface reflectance without increasing parasitic absorption within the anti-reflection coating(s); (2) to maximize internal back reflectance of rear passivated cells, thereby increasing optical absorption of weakly absorbed long wavelength photons (? > 900 nm); (3) to minimize recombination losses by providing excellent surface passivation; and (4) to improve doping processes during cell manufacturing (e.g., emitter and surface field formation) by functioning as highly controllable dopant sources compatible with in-line diffusion processes. The oxide materials deposited by APCVD include amorphous and polycrystalline titanium oxide, aluminum oxide, boron-doped aluminum oxide, silicon oxide, phosphosilicate glass, and borosilicate glass. The microstructure, optical properties, and electronic properties of these films are characterized for different deposition conditions. Additionally, the impact of these materials on the performance of different types of c-Si solar cells is presented using both simulated and experimental current-voltage curves.
330

Tribological Thin Films on Steel Rolling Element Bearing Surfaces

Evans, Ryan David January 2006 (has links)
No description available.

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