by Chiah Man Fat. / Thesis submitted in: September 1999. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 94-97). / Abstracts in English and Chinese. / Acknowledgements --- p.2 / Abstract --- p.3 / Table of Contents --- p.5 / List of Figures --- p.7 / List of Tables --- p.13 / Chapter Chapter 1 --- Introduction --- p.14 / Chapter 1.1. --- Overview --- p.14 / Chapter 1.2. --- Giant Magnetoresistance (GMR) --- p.15 / Chapter 1.3. --- Application of GMR Materials --- p.20 / Chapter 1.4. --- Preparation Methods --- p.22 / Chapter 1.5. --- This Thesis --- p.23 / Chapter Chapter 2 --- Sample Preparation and Experimental Methods --- p.24 / Chapter 2.1. --- MEVVA Ion Source Implanter --- p.24 / Chapter 2.2. --- The Pulsed Filtered Cathodic Arc Co-deposition System --- p.26 / Chapter 2.3. --- Sample Preparation --- p.29 / Chapter 2.3.1 --- Implantation Condition --- p.29 / Chapter 2.3.2 --- Co-deposition Conditions --- p.31 / Chapter 2.4. --- Characterization methods --- p.32 / Chapter 2.4.1 --- Magnetoresistance Measurement --- p.32 / Chapter 2.4.2 --- Atomic Force Microscopy and Magnetic Force Microscopy --- p.34 / Chapter 2.4.3 --- Rutherford Backscattering Spectroscopy (RBS) --- p.37 / Chapter 2.4.4 --- SQUID Magnetometer --- p.38 / Chapter Chapter 3 --- Characterization of Implanted Samples --- p.39 / Chapter 3.1. --- Introduction --- p.39 / Chapter 3.2. --- Results and Discussion --- p.39 / Chapter 3.2.1 --- Ag Film Thickness Dependence --- p.39 / Chapter 3.2.2 --- Dose Dependence --- p.44 / Chapter 3.2.3 --- Extraction Voltage Dependence --- p.46 / Chapter 3.2.4 --- Annealing Temperature Dependence --- p.49 / Chapter 3.2.5 --- Thicker Layer Formation --- p.56 / Chapter 3.2.6 --- AFM and MFM Measurements --- p.58 / Chapter 3.3. --- Summary --- p.64 / Chapter Chapter 4 --- Characterization of Co-deposited Samples --- p.65 / Chapter 4.1. --- Introduction --- p.65 / Chapter 4.2. --- Results and discussion --- p.65 / Chapter 4.2.1 --- RBS Measurement --- p.65 / Chapter 4.2.2 --- Magnetoresistance Measurement --- p.66 / Chapter 4.2.3 --- AFM Measurement --- p.69 / Chapter 4.2.4 --- MFM Measurement --- p.76 / Chapter 4.3. --- Summary --- p.84 / Chapter Chapter 5 --- Conclusion --- p.85 / Chapter 5.1. --- Main Results of This Work --- p.85 / Chapter 5.2. --- Suggestions on Future Works --- p.87 / Appendix --- p.89 / Reference --- p.94 / Publications --- p.97

Lau Wing Fai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 101-105). / Abstracts in English and Chinese. / Abstract --- p.i / Abstract (Chinese version) --- p.iii / Acknowledgement --- p.iv / Content --- p.v / List of figure caption --- p.vii / List of table caption --- p.xi / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Nomenclature --- p.1 / Chapter 1.2 --- Comparison of diamond and DLC --- p.2 / Chapter 1.3 --- Comparison of the amorphous hydrogenated and hydrogen free amorphous carbon --- p.4 / Chapter 1.4 --- Application of DLC --- p.7 / Chapter 1.5 --- ta-C growth mechanism --- p.9 / Chapter 1.6 --- Recent activities on ta-C films --- p.11 / Chapter 1.7 --- Goal of this project and organization of this thesis --- p.11 / Chapter Chapter 2 --- Deposition of ta-C films / Chapter 2.1 --- Ta-C film deposition systems --- p.12 / Chapter 2.1.1 --- Direct ion beam deposition --- p.13 / Chapter 2.1.2 --- Laser ablation --- p.14 / Chapter 2.1.3 --- Mass selected ion beam deposition (MSIBD) --- p.15 / Chapter 2.1.4 --- Arc discharge and filtered arc discharge (FAD) methods --- p.16 / Chapter 2.2 --- The pulsed filtered vacuum arc deposition system --- p.18 / Chapter 2.2.1 --- Working principle --- p.18 / Chapter 2.2.2 --- Film thickness control --- p.20 / Chapter 2.3 --- System modification --- p.22 / Chapter 2.3.1 --- Cathode erosion improvement --- p.22 / Chapter 2.3.2 --- Enhancement of stabilization of the cathodic arc --- p.23 / Chapter 2.4 --- Sample preparation --- p.24 / Chapter 2.4.1 --- Film deposition --- p.24 / Chapter 2.4.2 --- Thermal treatments --- p.24 / Chapter Chapter 3 --- Characterization methods / Chapter 3.1 --- Raman spectroscopy --- p.25 / Chapter 3.2 --- IR Photoelasticity (PE) --- p.27 / Chapter 3.2.1 --- Basic principle --- p.27 / Chapter 3.2.2 --- Senarmont method --- p.30 / Chapter 3.3 --- Ellipsometry --- p.33 / Chapter 3.3.1 --- Principle of ellipsometry --- p.33 / Chapter 3.3.2 --- Mathematical representation --- p.37 / Chapter 3.3.2a --- Bulk layer --- p.37 / Chapter 3.3.2b --- Single layer structure --- p.38 / Chapter 3.3.3 --- Spetroscopioc rotating analyzer ellipsometer --- p.39 / Chapter 3.3.4 --- Analysis method --- p.42 / Chapter 3.3.5 --- Forouhi and Bloomer (F.B.) model --- p.43 / Chapter 3.4 --- Tribology --- p.44 / Chapter 3.4.1 --- The definition of friction --- p.44 / Chapter 3.4.2 --- Tribometer --- p.46 / Chapter Chapter 4 --- Results / Chapter 4.1 --- As-deposited samples --- p.47 / Chapter 4.1.1 --- Sp3 fraction --- p.47 / Chapter 4.1.2 --- Stress --- p.52 / Chapter 4.1.3 --- Optical properties --- p.57 / Chapter 4.1.3.1 --- Optical model for ta-C film --- p.57 / Chapter 4.1.3.2 --- Figure of merit --- p.59 / Chapter 4.1.3.3 --- Result and discussion --- p.59 / Chapter 4.1.4 --- Mechanical properties --- p.70 / Chapter 4.1.4.1 --- Hardness --- p.70 / Chapter 4.1.4.2 --- Friction --- p.76 / Chapter 4.2 --- Annealed samples --- p.81 / Chapter 4.2.1 --- Thermal stability of the ta-C film --- p.81 / Chapter 4.2.2 --- Stress relaxation --- p.85 / Chapter 4.2.3 --- Stress and G peak shift --- p.92 / Chapter Chapter 5 --- Future work / Chapter 5.1 --- Film roughness and thickness profile improvement --- p.95 / Chapter 5.2 --- Pulsed substrate bias --- p.97 / Chapter 5.3 --- Field emission and doping possibility --- p.97 / Chapter Chapter 6 --- Conclusion --- p.98 / Reference --- p.101 / Conference / publications --- p.105

Au Yeung Yue Fung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / Au Yeung Yue Fung. / Abstract --- p.i / 論文摘要 --- p.ii / Acknowledgements --- p.iii / Table of Contents --- p.iv / List of Figures --- p.vi / List of Tables --- p.viii / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Genesis --- p.1-1 / Chapter 1.2 --- Aims and Objectives --- p.1-2 / Chapter 1.3 --- Layout of thesis --- p.1-3 / References --- p.1-4 / Chapter Chapter 2 --- Literature review / Chapter 2.1 --- Introduction to superconductor --- p.2-1 / Chapter 2.2 --- MgB2 --- p.2-3 / Chapter 2.2.1 --- Significance of MgB2 --- p.2-3 / Chapter 2.2.2 --- Structure and properties of MgB2 --- p.2-4 / Chapter 2.2.3 --- Superconducting mechanism of MgB2 --- p.2-5 / Chapter 2.2.4 --- Physical properties of boron and boride --- p.2-7 / Chapter 2.2.5 --- Physical properties of magnesium --- p.2-7 / Chapter 2.2.6 --- Formation of MgB2 --- p.2-8 / Chapter 2.2.7 --- MgB2 thin films --- p.2-9 / Chapter 2.2.7.1 --- Substrate --- p.2-11 / Chapter 2.2.7.2 --- Substrate temperature --- p.2-12 / Chapter 2.3 --- Contradictions as revealed by existing literatures --- p.2-13 / References --- p.2-14 / Chapter Chapter 3 --- Preparation and characterization of bulk MgB2 / Chapter 3.1 --- Bulk MgB2 fabrication / Chapter 3.2 --- Measurement and analysis techniques of bulk MgB2 --- p.3-4 / Chapter 3.2.1 --- XRD --- p.3-4 / Chapter 3.2.2 --- Meissner effect measurement --- p.3-5 / Chapter 3.3 --- Sintering time of MgB2 --- p.3-6 / Chapter 3.4 --- Concentration of Mg in sintering MgB2 --- p.3-8 / Chapter 3.5 --- Sintering temperature of MgB2 --- p.3-11 / Chapter 3.6 --- Thermal stability of MgB2 --- p.3-13 / Chapter 3.7 --- MgB2 in water --- p.3-17 / References --- p.3-19 / Chapter Chapter 4 --- Preparation and characterization of MgB2thin films / Chapter 4.1 --- Thin film deposition --- p.4-1 / Chapter 4.1.1 --- Facing-target sputtering (FTS) --- p.4-2 / Chapter 4.1.2 --- Vacuum system --- p.4-4 / Chapter 4.1.3 --- Asymmetric bipolar pulsed DC power source --- p.4-6 / Chapter 4.2 --- Fabrication of MgB2 targets --- p.4-10 / Chapter 4.3 --- Substrates --- p.4-11 / Chapter 4.4 --- Deposition procedure --- p.4-12 / Chapter 4.5 --- Deposition condition --- p.4-13 / Chapter 4.5.1 --- Deposition power --- p.4-15 / Chapter 4.5.2 --- Deposition pressure --- p.4-13 / Chapter 4.5.3 --- Annealing temperature --- p.4-18 / Chapter 4.5.4 --- Substrate temperature --- p.4-21 / Chapter 4.5.5 --- Conclusion --- p.4-26 / References --- p.4-29 / Chapter Chapter 5 --- Failed attempts of MgB2 films fabrication by in situ method / Chapter 5.1 --- In-situ method --- p.5-1 / Chapter 5.2 --- Additional FTS guns with Mg target --- p.5-2 / Chapter 5.3 --- Diode sputtering --- p.5-4 / Chapter 5.4 --- Co-evaporating fabrication --- p.5-6 / Chapter Chapter 6 --- Conclusion --- p.6-1

Orientador: Silvia Azucena Nebra de Perez / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-07-23T05:59:33Z (GMT). No. of bitstreams: 1 GuarineloJunior_FlavioFernando_M.pdf: 13289619 bytes, checksum: 071272a1f97f1b5a7cc53461f4f94b0e (MD5) Previous issue date: 1997 / Resumo: Este trabalho trata da aplicação de conceitos da termoeconomia à um estudo preliminar de um sistema de cogeração baseado em turbina a gás aeroderivativa e caldeira de recuperação, que visa suprir as demandas térmica e elétrica de um pólo industrial situado na cidade de Cabo -PE. É introduzida a análise energética, exergética e termoeconomica, para avaliar as eficiências segundo métodos e critérios específicos à sistemas de potência, para duas situações hipoteticamente admitidas quanto ao nível de geração de eletricidade - com e sem injeção de vapor na turbina a gás, que representam os perfis médios de demanda, segundo o fator de capacidade apresentado. Na análise termoeconôrnica são introduzidos alternativas de financiamento que possibilitam avaliar os reflexos dos custos de capital e combustível na composição dos custos da eletricidade e do vapor, segundo os métodos de alocação passíveis de serem aplicados a sistemas de cogeração. As alternativas de financiamento são ainda submetidas à técnicas conhecidas de análise de investimentos / Abstract: The main purpose of this work is to apply the Thermoeconomics concepts to a preliminary study of a cogeneration system, based on a gas turbine and HRSG, which objects to attend the thermal and electrical demand of an industrial complex, sited in Cabo-PE. The power plant is evaluated on the basis of the First and Second Law. Also the Thermoeconomic analysis, was applied for two hypothetical operation conditions, as regards the leveI of electric power generation - with and without steam injection in the gas turbine, which represents the middle demand outline, according to presented capacity factor. In the thermoeconomic analysis is introduced project finance options generally used in Brasil, what permits an evaluation of capital and fuel costs considering in the electricity and steam costs, according to allocation methods susceptible to be applied in cogeneration systems. The financirtg options, are subjected to known technics of investments analysis / Mestrado / Energia / Mestre em Engenharia Mecânica

The vapor phase photochemistry of the three isomeric cyanopyridines and the three methylpyridines was studied by irradiating their vapors at 254 nm. It was found that direct irradiation of any one cyanopyridine isomer resulted in the formation of the other two isomers of cyanopyridine or methylpyridines respectively. The reactivity of each isomer was found to be different. This was suggested to be based on the stability of their azaprefulvene intermediates formed during interconversion. The phototransposition of these molecules was suggested to result from 2,6-bonding, nitrogen migration around the five sides of cyclopentenyl ring followed by rearomatization. This mechanism was found to be consistent with the results of deuterium labeling studies of cyanopyridines These result suggest that cyanopyridines undergo phototransposition via the intermediacy of azaprefulvenes instead of Dewar-pyridine and azaprismane. Thus, photochemical studies showed that the six trideuteriopyridine isomers constitute two separate photochemical triads. Each triad consists of three isomers that are photointerconverting upon irradiation at 254 nm in the vapor phase. Similary, it was found that the three isomeric tetradeuteriopyridine isomers also constitute a photochemical triad and are interconverting upon irradiation at 254 nm in the vapor phase. These phototranspositions are best explained by the cyclization, nitrogen migration, and rearomatization mechanism. These results are in contrast to the long-held belief that pyridine is photostable in the vapor phase. Instead, unlabeled pyridine undergoes a hidden phototransposition leading back to itself.

"In the past decade nanomaterials have attracted the interest of scientists and engineers all over the world due to their unique properties. Through their devoted experimental efforts, limited advances have been made on the synthesis of nanomaterials, the integration of nanomaterials into the structures of larger scales, and the property study of nanomaterials to explore possible applications. Despite the huge amount of money, resources, and effort invested in nanomaterials, several challenges still remain as obstacles on the way towards the successful large scale use of nanomaterials to benefit human life and society. For example, the need for low-cost, robust, and highly productive manufacturing methods and the demand for efficient integration of nanomaterials with materials and devices of larger length scales are still left unmet. The objective of this work was to utilize cost-efficient nanofabrication methods such as template-assisted fabrication, electrodeposition, and chemical vapor deposition to fabricate nanomaterials, integrate nanomaterials with larger structures to form a hierarchical composite, and explore the application of unique nanostructured electrode in lithium-ion batteries. Thus the thesis consists of three main parts: (1) fabrication of one-dimensional inorganic nanomaterials such as metal nanowires, metal nanorods, and carbon nanotubes with good control over shape and dimension; (2) synthesis of hierarchical carbon nanofibers on carbon microfibers and/or glass microfibers; and (3) development of nanostructured anodes to improve high-rate capability of lithium-ion batteries by adapting nanorod arrays as miniature current collectors. "

Thermal barrier coatings (TBCs) of ZrO2-7wt% Y2O3 were deposited by electron beam physical vapor deposition (EB-PVD) onto stationary flat plates and cylindrical surfaces in a multiple ingot coater. Crystallographic texture, microstructure, and deposition rate were investigated in this thesis. The crystallographic texture of EB-PVD TBCs deposited on stationary flat surfaces has been experimentally determined by comparing pole figure analysis data with actual column growth angle data. It was found that the TBC coating deposited directly above an ingot exhibits <220> single crystal type crystallographic texture. Coatings deposited between and off the centerline of the ingots the exhibited a <311>-type single crystal texture. For coatings deposited in the far corners of the coating chamber either a <111> fiber texture or a <311> single crystal type texture existed. The crystallographic texture of EB-PVD TBCs deposited on cylindrical surfaces was characterized using x-ray diffraction (XRD) at different angular positions on the cylinder substrate. XRD results revealed that crystallographic texture changes with angular position. Changes in crystallographic texture are attributed to the growth direction of the columns and substrate temperature. Growth direction is controlled by the direction of the incoming vapor flux (i.e. vapor incidence angle), in which competition occurs between crystallites growing at different rates. The fastest growing orientation takes over and dominates the texture. Substrate temperature variations throughout the coating chamber resulted in different growth rates and morphology. Morphology differences existed between cylindrical and flat plate surfaces. Flat cross sectional surfaces of the coatings exhibited a dense columnar structure in which the columns grew towards the closest vapor source. Surface features were found to be larger for coatings deposited directly above an ingot than coatings deposited away from the ingots. Morphological differences result from substrate temperature changes within the coating chamber, which influences growth kinetics of the coating. Cylindrical surfaces revealed a columnar structure in which columns grew towards the closest vapor. Porosity of the coating was found to increase when the angular position changed from the bottom of the cylinder. Change in angular position also caused the column diameter to decreases. Morphology changes are attributed to self-shadow effects caused by the surface curvature of the cylinder and vapor incidence angle changes. Overall, the microstructure and crystallographic texture of EB-PVD coatings was found to depend on the position in the coating chamber which was found to influence substrate temperature, growth directions, and shadowing effects. The coating thickness profiles for EB-PVD TBCs deposited on stationary cylinders have been experimentally measured and theoretically modeled using Knudsen's cosine law of emissions. A comparison of the experimental results with the model reveals that the model must to be modified to account for the sticking coefficient as well as a ricochet factor. These results are also discussed in terms of the effects of substrate temperature on the sticking coefficient, the ricochet factor, and coating density.

A presença de sais no petróleo ocasiona grandes problemas operacionais relacionados à corrosão, uma vez que estes acabam formando ácido clorídrico no processo de separação do óleo bruto. Com o intuito de amenizar os efeitos de corrosão ácida, aminas podem ser adicionadas no topo das colunas para agir como neutralizantes. Porém, dependendo das condições operacionais e da quantidade de amina adicionada, pode ocorrer a deposição de cloridratos de aminas, promovendo a corrosão sob depósito. Assim, o conhecimento da pressão de sublimação desses sólidos é de extrema importância para especificar as condições de operação e o melhor desempenho destes aditivos no processo. Dentro desse contexto, o objetivo deste trabalho é determinar as pressões e entalpias de sublimação de cloridratos de aminas com a técnica termogravimétrica. Devido às dificuldades encontradas para obtenção de dados precisos de pressão em baixas temperaturas, uma extensão ao método termogravimétrico foi proposta, tornando possível medir pressões na ordem de 1 0,5 Pa. As substâncias estudadas foram: brometo de amônio, cloreto de amônio, cloridrato de etanolamina, cloridrato de metilamina, cloridrato de piridina, cloridrato de trimetilamina e dicloridrato de n-(1- naftil)etilenodiamina. Resultados de pressão e entalpia de sublimação alcançados com ácido benzoico, brometo de amônio e cloreto de amônio foram validados com dados da literatura Para os demais sólidos estudados, não há muitos dados disponíveis na literatura. No entanto, como a reação de sublimação do cloreto de amônio é análoga à dos demais cloridratos de amina, as entalpias de sublimação puderam ser comparadas e os resultados encontrados foram satisfatórios. Por fim, para uma melhor aplicabilidade dos resultados obtidos, uma equação de Clausius-Clapeyron modificada foi utilizada para correlacionar os dados medidos. Uma ótima correlação foi possível para todos os sais estudados, com coeficiente de correlação sempre superior a 0,97. / The presence of salts in petroleum causes operational problems related to corrosion, due to the fact that they end up forming hydrochloric acid in the crude oil separation process. In order to mitigate the effects of acid corrosion, amines can be added at the top of the columns to act as neutralizers. However, depending on the operational conditions and the amount of amine added, a deposition of amine hydrochlorides may occur, promoting under-deposit corrosion. Thus, the knowledge of the sublimation pressure of these salts has an extreme importance in trying to predict and to optimize the performance of the additives in the process. Within this context, the purpose of this study is to determine pressure and enthalpy of sublimation of amine hydrochlorides with the thermogravimetric technique. Due to the difficulties encountered to obtain precise pressure data at low temperatures, an extension of the thermogravimetric method was proposed, enabling to measure sublimation pressures in the order of 1 0,5 Pa. The substances studied were: ammonium bromide, ammonium chloride, ethanolamine hydrochloride, methylamine hydrochloride, pyridine hydrochloride, trimethylamine hydrochloride and n-(1-naphthyl)ethylenediamine dihydrochloride. Results of pressure and enthalpy of sublimation obtained with benzoic acid, ammonium bromide and ammonium chloride were validated using literature data. For other solids investigated in this study, experimental data is scarce in the literature. However, as the sublimation reaction of ammonium chloride is analogous to the others amine hydrochlorides, enthalpies of sublimation could be compared with the results found. Since similar values were observed, the results were considered satisfactory. Finally, the measured data were correlated using a modified Clausius-Clapeyron equation. A good correlation was possible for all salts studied, with correlation coefficient always higher than 0.97.

O presente trabalho estuda a produção e modificações físico-químicas do grafeno frente a tratamentos térmicos. Em uma primeira etapa, foi investigada a síntese de grafeno pela técnica de Deposição Química a partir da fase Vapor (CVD) sobre fitas de cobre. Nós variamos quatro parâmetros que influenciam no crescimento de grafeno: fluxo de metano (CH4), fluxo de hidrogênio (H2), tempo de crescimento e grau de pureza do cobre. Usando as técnicas de caracterização de espectroscopia Raman e microscopia óptica, observamos que fluxo menor de H2 e fluxo intermediários de CH4 favorecem o crescimento de grafeno de alta qualidade. Além disso, vimos que 15 minutos de crescimento de grafeno é suficiente para cobertura do substrato de cobre com grafeno. Por fim, foi visto que o maior grau de pureza do cobre permite a produção de monocamadas de grafeno mais homogêneas. Numa segunda etapa, foi realizado um estudo com objetivo de entender a interação de hidrogênio com monocamadas de grafeno. Nós usamos amostras de grafeno depositadas em filmes de SiO2 (285 nm)/Si e tratadas termicamente em atmosfera controlada de deutério (99,8%) em temperaturas entre 200 e 800 °C. Nós também investigamos a dessorção de hidrogênio do grafeno usando amostras previamente tratadas em deutério a 600 °C e depois tratadas em atmosfera controlada de nitrogênio em temperaturas entre 200 e 800 °C. Após os tratamentos, análise por reação nuclear (NRA) foi realizada para quantificar o deutério, onde nós observamos uma grande incorporação de deutério no grafeno acima de 400 °C, tendo um aumento moderado até 800 °C. Nós também observamos que a dessorção do deutério do grafeno ocorre apenas em 800 °C, embora a dessorção de deutério do óxido de silício ocorra a partir de 600°C. Espectroscopia Raman também foi realizada após cada tratamento térmico. Os resultados mostram que os defeitos na estrutura do grafeno têm um grande aumento para as etapas de maior temperatura na incorporação de deutério. Análises realizadas com Espectroscopia de Fotoelétrons Induzidos por Raios X (XPS) mostraram que a incorporação de deutério para maiores temperaturas causa o "etching" do grafeno. Por fim, caracterizações usando Espectroscopia de Absorção de Raios X (NEXAFS) mostraram que o deutério liga-se ao grafeno sem orientação preferencial. / The present work studies the production and physical-chemical modifications of the graphene under thermal annealings. In a first study, the graphene synthesis by Chemical Vapor Deposition (CVD) on copper foils was investigated. We varied four parameters that influence the growth of graphene: methane flow (CH4), hydrogen flow (H2), growth time and copper purity. Using Raman spectroscopy and optical microscopy, we observed that lower flux of H2 and intermediate flux of CH4 leads to the growth of high quality graphene. In addition, we observed that 15 minutes growth of graphene is sufficient to cover the copper substrate. A higher copper purity allows the production of homogeneous graphene monolayers. In a second step, a study was carried out to understand the interaction of hydrogen with graphene monolayers. We used graphene samples deposited on SiO2 (285 nm)/Si films and annealed in a controlled atmosphere of deuterium (99.8%) at temperatures between 200 and 800 °C. We also investigated the hydrogen desorption of graphene using samples previously treated in deuterium at 600 °C and then annealed in a controlled atmosphere of nitrogen at temperatures between 200 and 800 °C. After the annealings, nuclear reaction analysis (NRA) was performed to quantify the deuterium, where we observed a large incorporation of deuterium in graphene above 400 °C, with a moderate increase up to 800 °C. We also observed that desorption of deuterium occurs only at 800 °C, although deuterium desorption from silicon oxide occurs at 600 °C. Raman spectroscopy was also performed after each annealing. The results show that defects in the structure of graphene have a large increase for deuterium incorporation. Analyzes carried out with X-ray Photoelectron Spectroscopy (XPS) showed that the deuterium incorporation at higher temperatures leads to graphene etching. Finally, characterizations using X-ray Absorption Spectroscopy (NEXAFS) showed that deuterium binds to graphene without preferential orientation.

"August 1999." / Thesis (Ph.D.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.