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Huang, Chun Fuk = 間層對龐磁阻多層薄膜的傳導與擴散特性的影響 / 黃真福. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / Huang, Chun Fuk = Jian ceng dui pang ci zu duo ceng bo mo de chuan dao yu kuo san te xing de ying xiang / Huang Zhenfu. / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Magnetoresistance --- p.1 / Chapter 1.1.1 --- Giant magnetoresistance (GMR) --- p.3 / Chapter 1.1.2 --- Colossal magnetoresistance (CMR) --- p.5 / Chapter 1.1.3 --- Double exchange mechanism --- p.6 / Chapter 1.1.4 --- Jahn-Teller effect --- p.10 / Chapter 1.1.5 --- Tolerance factor --- p.12 / Chapter 1.1.6 --- Effect of Doping --- p.14 / Chapter 1.1.7 --- Charge-ordering effect --- p.16 / Chapter 1.1.8 --- Phase separation and percolation theory --- p.17 / Chapter 1.2 --- Our motivation --- p.18 / Chapter 1.3 --- Review of manganite multilayer system --- p.20 / Chapter 1.4 --- Scope of this thesis --- p.21 / References --- p.22 / Chapter Chapter 2 --- Instrumentation / Chapter 2.1 --- Thin film deposition --- p.24 / Chapter 2.1.1 --- Facing-target sputtering (FTS) --- p.24 / Chapter 2.1.2 --- Vacuum system --- p.26 / Chapter 2.2 --- Oxygen annealing system --- p.28 / Chapter 2.3 --- Characterization --- p.30 / Chapter 2.3.1 --- α-step profilometer --- p.30 / Chapter 2.3.2 --- X-ray diffraction (XRD) --- p.30 / Chapter 2.3.3 --- Resistance measurement --- p.32 / References --- p.34 / Chapter Chapter 3 --- Epitaxial growth of LCMO and LSMO single layer thin films / Chapter 3.1 --- Fabrication and characterization of LCMO and LSMO targets --- p.35 / Chapter 3.2 --- Epitaxial growth of LCMO and LSMO thin films --- p.41 / Chapter 3.2.1 --- Substrate materials --- p.41 / Chapter 3.2.2 --- Deposition conditions --- p.42 / Chapter 3.2.3 --- Deposition procedures --- p.44 / Chapter 3.3 --- Characterization of single layer films --- p.45 / References --- p.50 / Chapter Chapter 4 --- Lao.67Ca0.33MnO3/La0.4Ca0.6MO3 multilayers and La0.67Ca0.33MnO3 /La0.2̐ơإSr0.75MnO3 multilayers / Chapter 4.1 --- Sample preparation --- p.51 / Chapter 4.2 --- As-grown multilayers --- p.53 / Chapter 4.2.1 --- Structural characterization of as-grown samples --- p.53 / Chapter 4.2.2 --- Transport properties of as-grown samples --- p.59 / Chapter 4.3 --- Oxygen post annealing of multilayer thin films --- p.68 / Chapter 4.3.1 --- Introduction to post annealing of manganite oxides --- p.68 / Chapter 4.3.2 --- Oxygen post annealing conditions --- p.69 / Chapter 4.4 --- Results and discussion of oxygen post-annealing samples --- p.71 / Chapter 4.4.1 --- Structural characterization of oxygen post-annealing samples --- p.71 / Chapter 4.1.1.1 --- Effect of chemical composition --- p.71 / Chapter 4.4.1.2 --- Effect of relative thickness --- p.73 / Chapter 4.4.2 --- Transport properties of oxygen post-annealing samples --- p.84 / References --- p.95 / Chapter Chapter 5 --- Conclusion --- p.97

Thesis (M.S.)--Rochester Institute of Technology, 1989. / Spine Title: Optically transparent heat mirror films. Includes bibliographical references (leaves 58-59).

Current technology has made possible the fabrication of multilayered optical elements for soft x-ray radiation. These structures find a variety of important applications. Difficulties in the design and fabrication of multilayers for soft x-rays are related to the lack of information about the properties of materials in the very thin layers (~5-100 Å) required. Imperfections cause the measured optical properties of the multilayers to deviate strongly from ideal behavior. Realistic calculations of reflectance must take these imperfections into account. We review the pertinent theory, with attention to the problem of including non-ideal properties. We also review characterization techniques suitable for the measurement of relevant structural and stoichiometric parameters of the multilayer. A detailed characterization procedure is presented. This procedure is capable of accurately determining the layer thicknesses, material densities, interfacial rms roughness or diffusion values, crystalline structure, concentration of contaminants, and extent of surface oxidation. The techniques used included low-angle x-ray θ-2θ diffraction with parallel-beam and Bragg-Brentano geometries, wide-film Debye-Scherrer ("Read") camera and Seemann-Bohlin diffractometer, Rutherford backscattering spectroscopy, and transmission electron microscopy. Si/W multilayer mirrors were designed for normal-incidence 210 Å radiation. Samples were fabricated using a magnetically-confined-plasma dc-triode sputtering technique. Our characterization procedure was applied to these samples. To our knowledge, this is the first time such a comprehensive set of characterization techniques has been applied to a multilayer x-ray optical element. The same samples were tested with synchrotron radiation over a wide spectral range, and for several incidence angles. The measured reflectance is in excellent agreement with curves calculated using the information obtained from the characterization results, with no adjustable parameters. The Si/W combination is shown to have good layering characteristics. The near-normal reflectance of the multilayers was 20 to 30 times better than the reflectivity of the best single-surface mirrors at the same wavelengths.

Theoretical considerations for the use of chalcopyrite ternary I-III-VI₂ compounds in heterojunction photovoltaic conversion devices are presented, followed by an in-depth study of the structural, optical, and electrical characteristics of multi-source evaporated CuGaSe₂ thin films as determined by processing. Film composition was identified as the primary variable for affecting the microstructure and optical-electrical behavior of the films. Film composition was in turn dependent upon elemental flux rates and substrate related effects. Films deposited on glass and bare alumina substrates were richer in selenium than films deposited on molybdenum coated substrates. Cu-poor, near stoichiometeric, and Cu-rich compositions were obtained by varying the Cu/Ga flux ratio. Cu-poor films deposited on bare ceramic substrates were characterized by secondary impurity phase content and a tendency for cubic CuGaSe₂ formation. The cubic nature of optically thin films deposited on glass was substantiated by a lack of crystal field splitting of the valence band as observed by optical absorption measurements. Cubic-tetragonal phase behavior was monitored on optically opaque samples by observation of intensity-independent (112)/(111) x-ray diffraction peak shifts. Cu-poor films on glass were also characterized by surfaces pitting at substrate temperatures in excess of 450°C which may be related to the high surface energy of gallium. Cu-poor films deposited on molybdenum coated alumina substrates exhibited less impurity phase formation and were largely single-phase tetragonal CuGaSe₂. Cu-rich films on all substrates contained CuₓSe impurities and tetragonal CuGaSe₂.

Voltammetric and spectroelectrochemical results are presented for the one-electron reduction of n-heptyl viologen on clean and silane-modified tin oxide, and on ion-beam modified, indium-tin oxide metallized plastic optically transparent electrodes (ITO MPOTE) surfaces. The use of viologens (dialkyl and diaryl 4,4' bipyridium compounds) in redox chromic displays is well known with a number of papers and patents discussing their use. The ability to vary the coloration rates of the electrochromic reaction of these compounds can be strongly influenced by the state of the electrode surface. Potential-step experiments, where the electrode potential is controlled at low overpotentials, has shown that the viologen reduction occurs through a nucleation process. The work here indicates that an "instantaneous nucleation" model appears to be the favored pathway for the n-heptyl viologen reaction. Chronoabsorptometric analysis of the nucleation process is made possible by monitoring the strongly absorbing viologen cation radical. Chronoabsorptometric data can be used to calculate the nucleation site density on an electrode surface. On silane-modified and ion-beam modified electrode surfaces, a more preferred nucleation site is found for the deposition of the first monolayers of viologen. Through the attachment of a silane or the ion-beam modification of an ITO metallized plastic film (ITO MPOTE), a nonpolar layer is created adjacent to the electrode surface. Prior to electrochemical reduction the n-heptyl viologen dication is partioned and concentrated into this nonpolar layer. The effect is a preconcentration of the viologen next to the electrode surface resulting in a fixed number of nucleation sites and an enhancement of the nucleation rate.

Orientador: Marystela Ferreira / Banca: Thiago Regis Longo Cesar da Paixão / Banca: Laura Oliveira Peres Philadelphi / Banca: Nilson Cristino da Cruz / Banca: Margarida Juri Saeki / Resumo: Neste trabalho, foram desenvolvidos biossensores eletroquímicos enzimáticos fabricados com óxido de grafeno reduzido (rGO) e funcionalizado depositados pelas técnicas LbL (Layer-by-Layer) e Langmuir-Blodgett (LB) para a detecção de glicose. Para isso, primeiramente foi sintetizado quimicamente o óxido de grafeno (GO) pela oxidação do grafite, em seguida, o GO foi reduzido para aumentar a sua condutividade elétrica e foi funcionalizado em meio estabilizante contendo cloridrato de poli(dialildimetilamônio), formando o GPDDA, ou poli(4-estireno sulfônico) PSS, formando GPSS. Com isso, foi possível formar dispersões aquosas estáveis das nanofolhas de grafeno, essencial para a fabricação de filmes LbL. Em um primeiro momento, foram fabricados biossensores com filmes LbL contendo GPDDA, GPSS e a enzima glucose oxidase (Gox). O desempenho desses biossensores na detecção de glicose foi avaliado em função do número de bicamadas contendo Gox. O melhor desempenho na detecção de glicose foi apresentado pelo biossensor com o filme LbL com a arquitetura (GPDDA/GPSS)/(GPDDA/GPSS)2. Este biossensor apresentou limite de detecção de 13,4 µmol.L-1, sensibilidade 2,47 μA.cm-2.mmol-1.L e faixa analítica entre 0,04 e 0,95 mmol.L-1. Este biossensor foi eficiente na detecção de glicose na presença de interferentes comumente encontrados em fluidos corporais, alimentos e fármacos. Quando avaliado na detecção de glicose em amostras reais, recuperou 100,8% para uma solução eletrolítica comercial e 88,8%... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In this work, enzymatic electrochemical biosensors fabricated with reduced graphene oxide (rGO) and functionalized deposited by the LbL (Layer-by-Layer) and LangmuirBlodgett (LB) techniques were developed for the detection of glucose. Firstly, to get this, graphene oxide (GO) was chemically synthesized by the oxidation of graphite and after GO was reduced to increase its electrical conductivity and it was functionalized in stabilizing medium containing the poly (diallyl dimethyl ammonium chloride) PDDA, forming the GPDDA, or poly (4-styrene sulphonic) PSS, forming GPSS. Hence, stable aqueous dispersions of graphene nanosheets were formed, essential for the fabrication of LbL films. In a first moment, biosensors with LbL films containing GPDDA, GPSS and the enzyme glucose oxidase (Gox) were fabricated. The performance of these biosensors in the detection of glucose was evaluated as a function of the number of bilayers containing Gox. The best performance in the detection of glucose was presented by the biosensor with the LbL film with the architecture (GPDDA/GPSS)/(GPDDA/GPSS)2. It presented a detection limit of 13.4 μmol.L-1, sensitivity 2.47 μA.cm-2 .mmol-1 .L and analytical range between 0.04 and 0.95 mmol.L-1 . This biosensor was efficient in detecting glucose in the presence of interferents commonly found in body fluids, foods and drugs. When evaluated in the detection of glucose in real samples, it recovered 100.8% for a commercial electrolytic solution and 88.8% for lactose-free milk. In a second moment, biosensors were fabricated from LB films containing the same materials used to fabricate the biosensors with LbL films (GPDDA, GPSS and Gox), in order to compare the two methods of films deposition in the performance of the biosensors. The performance of biosensors fabricated with LB films was evaluated in relation to the amount of deposited... (Complete abstract electronic access below) / Doutor

by Lai Yiu Wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / Abstract in English and Chinese. / Abstract / Abstract (Chinese) / Table of Contents / List of Figures / List of Tables / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Overview --- p.1-1 / Chapter 1.2 --- Conventional recording --- p.1-2 / Chapter 1.3 --- Superparamagnetism --- p.1-2 / Chapter 1.4 --- Possible solutions --- p.1-4 / Chapter 1.4.1 --- Perpendicular recording --- p.1-5 / Chapter 1.4.2 --- Patterned media --- p.1-6 / Chapter 1.4.3 --- High Ku material for recording media --- p.1-7 / Chapter 1.5 --- FePt-based material research 1 - --- p.1-8 / Chapter 1.6 --- Project goal --- p.1-11 / Reference --- p.1-12 / Chapter Chapter 2 --- Sample preparation and characterization techniques / Chapter 2.1 --- Pulsed filtered vacuum arc deposition (PFVAD) --- p.2-1 / Chapter 2.1.1 --- Sample preparation --- p.2-4 / Chapter 2.2 --- Rutherford backscattering spectroscopy (RBS) --- p.2-4 / Chapter 2.3 --- X-ray diffraction (XRD) --- p.2-6 / Chapter 2.4 --- Vibrating sample magnetometery (VSM) --- p.2-7 / Chapter 2.5 --- Transmission electron microscopy (TEM) --- p.2-9 / Reference --- p.2-10 / Chapter Chapter 3 --- Characterization of FePt-C nanocomposite thin film / Chapter 3.1 --- Experiment design --- p.3-1 / Chapter 3.2 --- Experiment detail --- p.3-1 / Chapter 3.3 --- Results and discussion --- p.3-3 / Chapter 3.3.1 --- NRBS measurements --- p.3-3 / Chapter 3.3.2 --- XRD measurements --- p.3-8 / Chapter 3.3.3 --- VSM measurements --- p.3-14 / Chapter 3.3.4 --- Some preliminary results on effects of post- deposition implantation --- p.3-23 / Chapter 3.3.5 --- TEM images --- p.3-26 / Chapter 3.3.6 --- Overall discussion --- p.3-29 / Chapter 3.3.6.1 --- Total film thickness effect --- p.3-29 / Chapter 3.3.6.2 --- Degree of ordering from XRD (001)/(002) peak intensity ratio --- p.3-33 / Chapter 3.3.6.3 --- C spacer thickness effect --- p.3-34 / Chapter 3.3.6.4 --- Implantation effect --- p.3-35 / Chapter 3.4 --- Summary --- p.3-35 / Reference --- p.3-36 / Chapter Chapter 4 --- Characterization of FePt-Cu nanocomposite thin film / Chapter 4.1 --- Experiment design --- p.4-1 / Chapter 4.2 --- Experiment detail --- p.4-1 / Chapter 4.3 --- Results and discussion --- p.4-3 / Chapter 4.3.1 --- RBS measurements --- p.4-3 / Chapter 4.3.2 --- XRD measurements --- p.4-7 / Chapter 4.3.3 --- VSM measurements --- p.4-9 / Chapter 4.3.4 --- Discussion --- p.4-12 / Chapter 4.3.4.1 --- Total film thickness effect --- p.4-12 / Chapter 4.3.4.2 --- Cu spacer thickness effect --- p.4-13 / Chapter 4.4 --- FePt films without additive --- p.4-16 / Chapter 4.5 --- Summary --- p.4-17 / Reference --- p.4-18 / Chapter Chapter 5 --- Conclusion and future works / Chapter 5.1 --- Conclusion --- p.5-1 / Chapter 5.2 --- Future works --- p.5-3 / Reference --- p.5-4 / Appendix 1 / Appendix 2

Wai, Kwai Fong = 錳氧化物 - 鈮摻雜之鈦酸鍶異構結的電流電壓關係測量 / 韋桂芳. / "Sept 2007." / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / Wai, Kwai Fong = Meng yang hua wu - ni shan za zhi tai suan si yi gou jie de dian liu dian ya guan xi ce liang / Wei Guifang. / Acknowledgement / Abstract / 論文摘要 / Table of content / List of Figures / List of Tables / Appendix A / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Structure and properties of perovskite manganites / Chapter 1.2 --- Magnetoresistance (MR) / Chapter 1.3 --- Giant Magnetoresistance (GMR) / Chapter 1.4 --- Colossal Magnetoresistance (CMR) / Chapter 1.4.1 --- Exchange interaction and CMR / Chapter 1.5 --- p-n junction / Chapter 1.5.1 --- Fundamentals of a p-n homojunction / Chapter 1.5.2 --- Deviations from the Ideal Diode / Chapter 1.5.2.1 --- Zener breakdown / Chapter 1.5.2.2 --- Avalanche / Chapter 1.5.3 --- Heterojunction / Chapter 1.6 --- Research motivation / Chapter 1.7 --- Scope of the thesis / References / Chapter Chapter 2 --- Experimental details / Chapter 2.1 --- Thin film deposition / Chapter 2.1.1 --- Facing target sputtering / Chapter 2.1.2 --- Vacuum system / Chapter 2.1.3 --- Deposition procedure / Chapter 2.2 --- Oxygen annealing system / Chapter 2.3 --- Silver electrode coating apparatus / Chapter 2.4 --- Characterization / Chapter 2.4.1 --- Alpha-step profilometer / Chapter 2.4.2 --- X-ray diffractometer / Chapter 2.4.3 --- Electrical transport property measurement / Chapter 2.4.3.1 --- Measurement of resistance as a function of temperature (RT) / Chapter 2.4.3.2 --- Measurement of I-V characteristics of a junction / References / Chapter Chapter 3 --- Epitaxial LSMO/STON heterojunction / Chapter 3.1 --- Sample preparation / Chapter 3.2 --- Results and Analysis / Chapter 3.2.1 --- Structural analysis / Chapter 3.2.2 --- R-T measurement / Chapter 3.2.3 --- I-V measurement / Chapter 3.2.3.1 --- Analysis of diffusion voltage and breakdown voltage / Chapter 3.2.3.2 --- Construction of energy band diagram of LSMO/STON at room temperature / Chapter 3.2.3.3 --- Investigating how the energy band structure varies with the temperature / Chapter 3.2.3.4 --- Further development of the energy band analyzing method to wide-p/narrow-n heteroj unction / Chapter 3.2.3.5 --- Forward-biased deviations from ideal / Chapter 3.2.3.6 --- Discussion on the reasons for deviations from ideal / Chapter 3.2.4 --- MR determination / References / Chapter Chapter 4 --- Epitaxial [LSMO/PCMO] multilayers and p-n junction / Chapter 4.1 --- [LSMO/PCMO]/NGO multi-layered thin films / Chapter 4.1.1 --- Sample preparation / Chapter 4.1.2 --- Results and analysis / Chapter 4.1.2.1 --- Structural analysis / Chapter 4.1.2.2 --- R-T measurement / Chapter 4.2 --- [LSMO/PCMO]/STON multi-layered junction / Chapter 4.2.1 --- Sample preparation / Chapter 4.2.2 --- Results and analysis / Chapter 4.2.2.1 --- Structural analysis / Chapter 4.2.2.2 --- R-T measurement / Chapter 4.2.2.3 --- I-V measurement / Chapter 4.2.2.3.1 --- Analysis of diffusion voltage and breakdown voltage / Chapter 4.2.2.3.2 --- Investigating the energy band structure as a function of temperature / Chapter 4.2.2.3.3 --- Forward-biased deviations from an ideal junction diode / Chapter 4.2.2.3.4 --- Review on MR calculation / Chapter 4.2.2.3.5 --- Analysis of MR of [LSMO(8 A ) /PCMO(8 A)]/STON and LSMO/STON / References / Chapter Chapter 5 --- [La0 4Ca0.6MnO3/La0.8Ca0.2MnO3］p-n junction / Chapter 5.1 --- Sample preparation / Chapter 5.2 --- Result and analysis / Chapter 5.2.1 --- Structural analysis / Chapter 5.2.2 --- R-T measurement / Chapter 5.2.3 --- I-V measurement / Chapter 5.2.3.1 --- Analysis of diffusion voltage and breakdown voltage / Chapter 5.2.3.2 --- Investigating the energy band structure as a function of temperature / Chapter 5.2.3.3 --- Forward-biased deviations from ideal / Chapter 5.2.3.4 --- MR analysis / Chapter Chapter 6 --- Conclusion / Chapter 6.1 --- Conclusion / Chapter 6.2 --- Future outlook

Thesis (Ph. D.)--University of California, San Diego, 2003. / Vita. Includes bibliographical references.