O nitreto de boro hexagonal (h-BN) tem uma estrutura cristalina similar ao grafite e é conhecido como um importante material cerâmico com propriedades interessantes, tais como a excelente estabilidade química, boa resistência à corrosão, baixa densidade, alto ponto de fusão e boa condutividade térmica. Estas características fazem do h-BN um candidato atraente para uma ampla gama de aplicações técnicas. Recentemente, muitos estudos têm relatado a preparação de estruturas de nitreto de boro (BN) com morfologias especiais, tais como nanofolhas, nanofios e nanotubos. Este trabalho apresenta uma rota de síntese de nanoestruturas de BN produzidas a partir de boro elementar, nitrato de amônio e hematita como catalisador, em forno tubular pelo método CVD (chemical vapor deposition). A mistura de pós foi aquecida a 550 C e esta temperatura foi mantida constante durante uma hora sem fluxo de gás. Em seguida a temperatura foi aumentada até 1300 C sob fluxo de gás nitrogênio; esta temperatura foi mantida por uma hora sob fluxo de nitrogênio e mais uma hora sob fluxo de gás amônia, depois disso foi feito o resfriamento da amostra sob fluxo de nitrogênio. Para avaliar a formação e a morfologia das nanoestruturas formadas em um segundo tratamento térmico, três valores de temperatura final foram estabelecidos: 900 , 950 , e 1300 C. A caracterização das amostras foi feita através de espectroscopia de infravermelho (FTIR), espectroscopia Mössbauer, difração de raios X (XRD), análise térmica (TGA/DSC), adsorção de N2, espectroscopia Raman, microscopia eletrônica de varredura (SEM), microscopia eletrônica de transmissão (TEM) e análise química elementar (CHN). A amostra que apresentou melhores resultados em relação à formação de h-BN foi purificada para remover partículas de ferro e algumas outras impurezas utilizando dois agentes distintos: ácido clorídrico e etanol. Através da análise dos resultados obtidos foi possível confirmar a formação do h-BN, e explicar as reações químicas envolvidas no processo. A partir das imagens de microscopia foi possível comprovar a formação de nanoestruturas de BN com morfologias variadas. Entre as nanoestruturas encontradas estão: nanofolhas, nanofibras, nanocones, bamboo-like, nanofios e nanotubos. Os nanotubos formados possuem diâmetro variando entre 10 e 120 nm. A presença de diversas estruturas com morfologias diferentes pode ser atribuída principalmente às variações no fluxo de gás durante a síntese. O teste inicial de citotoxicidade demonstrou que as nanoestruturas de nitreto de boro não apresentam atividade hemolítica considerável, indicando haver uma boa tolerância biológica. / Hexagonal boron nitride (h-BN) has a crystal structure similar to graphite and it is well known as one important ceramic material with interesting properties, such as excellent chemical stability, good resistance to corrosion, low density, high melting point, and outstanding thermal and electrical properties. These characteristics make h-BN an attractive candidate for a wide range of technical applications. Recently, many studies have been reporting the preparation of nanostructures of boron nitride (BN) with special morphologies, such as nanosheets and nanotubes. This paper reports a synthesis of boron nitride nanotubes produced from elemental boron powder, ammonium nitrate and hematite in tubular furnace by CVD (chemical vapor deposition) method. The powder mixture was heated at 550 C and this temperature was kept constant for one hour without gas flow. After that, the temperature was increased to 1300 C and kept constant for one hour under a nitrogen gas flow, then, another one under a flowing ammonia gas, followed by the cooling of the sample under nitrogen flow. To evaluate the formation and morphology of the nanostructures formed in a second heat treatment; three values of final temperature were established: 900, 950 and 1300 C. The Characterization of the samples was carried out by infrared spectroscopy (FTIR), Mössbauer spectroscopy, X-ray diffraction (XRD), thermal analysis (TGA/DSC), N2 adsorption, Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and elemental chemical analysis (CHN). The sample that showed better results regarding the formation of h-BN was purified to remove iron particles and some other impurities using two different agents: hydrochloric acid and ethanol. After the analysis of the results it was possible to confirm the formation of h- BN and to explain the chemical reactions involved. From microscopy images it was feasible to confirm the formation of BN nanostructures with distinct morphologies. Some different nanostructures were found: nanosheets, nanofibers, nanocones, "bamboolike", nanowires and nanotubes. The nanotubes formed have diameters ranging between 10 and 120 nm. The presence of several structures with different morphologies can be attributed mainly to variations in the flow of gas during the synthesis. Initial tests showed that the cytotoxicity of boron nitride nanostructures do not exhibit significant hemolytic activity, suggesting a good biological tolerance.

了解表面等子體和外部環境之間的相互作用對表面等子體應用的開發非常重要。我們的研究集中在表面等子體與遠場的耦合，以及表面等子體模之間的耦合。 / 首先，我們研究由表面等子體模式耦合所產生的射衰變的變化。我們以角分辨反射光譜測同孔大小的納米孔陣上的簡併表面等子體模的衰減。對於每個孔的大小，我們觀察到在發生共振耦合的光譜區，衰減速有很大的改變，顯示出暗模和模的形成。耦合模很好地解釋衰變的變化。推導出的耦合常隨著孔直徑的增加而增加。我們也對耦合模一些有趣的特性及衰減變化的微觀起源進探討。 / 第二，我們以偏振分辨反射光譜從二維屬陣射散射。我們發現，反射光譜遵循的法模型可以由耦合模和瓊斯矩陣演算推導出。通過用正交方向的偏光器和分析器，反射光譜上的谷翻轉成峰，從以能夠測定出射散射效。我們發現，射散射效與波長和孔直徑的依賴關係和單孔的瑞散射相符合。 / 最後，我們開發一個新的方法，以偏振分辨光譜在實驗中測射衰變。這方法的有效性通過時域有限差分計算得到證明。我們還將此方法應用在實驗據上作為示範。 / Understanding the interaction between surface plasmon and outer environment is crucial in development of plasmonic applications. Our study is focused on the coupling between surface plasmons and far field, and also the coupling between surface plasmon modes. / First, we studied the change in radiative decay rate due to coupling of degenerate surface plasmon modes. We measured the decay rates of two degenerate surface plasmon modes in Au nanohole arrays with different hole sizes by angle-resolved reflectivity spectroscopy. For each hole size, at the spectral region where resonant coupling occurs, we observed a large modification in decay rates, leading to the formation of dark and bright modes. The change in decay rates is well explained by coupled-mode theory. The deduced coupling constant is found to increase with increasing hole diameter. Interesting properties of the coupled modes and microscopic origin of the change in decay rate is also discussed. / Second, we measured the radiative scattering from two-dimensional metallic arrays by using polarization-resolved reflectivity spectroscopy. We found that the reflectivity spectra follow the Fano-like model which can be derived from coupled-mode theory and Jones matrix calculus. By orthogonally orienting the incident polarizer and the detection analyzer, reflectivity dips flip into peaks and the radiative scattering efficiency can be determined accordingly. The dependence of total radiative scattering efficiency on wavelength and hole diameter is found to agree well with Rayleigh scattering by single hole. / Finally, we developed a new method to measure radiative decay rates experimentally by polarization-resolved reflectivity spectroscopy. The validity of this method is proved by finite-difference time-domain simulation. We also applied this method on experimental data as a demonstration. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Lo, Hau Yung = 表面等離子體在金屬納米孔陣列的輻射衰減及耦合 / 羅孝勇. / "December 2012." / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 88-92). / Abstracts also in Chinese. / Lo, Hau Yung = Biao mian deng li zi ti zai jin shu na mi kong zhen lie de fu she shuai jian ji ou he / Luo Xiaoyong. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Basic Theory and Techniques --- p.3 / Chapter 2.1 --- Macroscopic Maxwell Equations and Boundary Conditions --- p.3 / Chapter 2.2 --- Symmetries and Band Structure --- p.4 / Chapter 2.3 --- Coupled-mode Theory --- p.10 / Chapter 2.4 --- Finite-difference Time-domain Simulation --- p.12 / Chapter 2.5 --- Preparation of Metallic Nano-hole Arrays --- p.14 / Chapter 3 --- Fundamentals of Surface Plasmons on Metallic Nanohole Array --- p.18 / Chapter 3.1 --- Confinement and Propagation Nature of SPs --- p.18 / Chapter 3.2 --- Skin Depth and Propagation Length --- p.19 / Chapter 3.3 --- Dispersion Relation and Phase-matching Conditions --- p.21 / Chapter 3.4 --- Measurement of Band Structure: Angle-resolved Reflectivity Mapping --- p.23 / Chapter 3.5 --- Red Shift of Band Structure --- p.26 / Chapter 3.6 --- Comparison of Two Presentations of Band Structure: "ω against k" versus "λ against θ" --- p.28 / Chapter 3.7 --- Resonance Peak Shape: FanoModel and Wood's Anomalus --- p.30 / Chapter 3.8 --- Resonance Peak Shape: "Fano-like" Model --- p.34 / Chapter 3.9 --- Appendix A: Derivation of Eq(3.1) --- p.36 / Chapter 4 --- Decay Rates Modification though Coupling of Degenerate Surface Plasmon modes --- p.40 / Chapter 4.1 --- Introduction --- p.40 / Chapter 4.2 --- Measurements of Degenerate Surface Plasmon Modes --- p.42 / Chapter 4.3 --- Decay rates of Coupled Modes --- p.45 / Chapter 4.4 --- Hole Diameter Dependence of Coupling Constants --- p.47 / Chapter 4.5 --- Understanding the S-polarized Surface Plasmon Modes --- p.50 / Chapter 4.6 --- TE-like Surface Plasmon Modes --- p.53 / Chapter 4.7 --- Microscopic Origin of the Modification in Decay Rate --- p.54 / Chapter 4.8 --- Summary --- p.60 / Chapter 5 --- Direct Measurement of Radiative Scattering of Surface Plasmon Resonance from Metallic Arrays by Polarization-resolved Reflectivity Spectroscopy --- p.61 / Chapter 5.1 --- Introduction --- p.61 / Chapter 5.2 --- Theory of Direct Measurement of Radiative Scattering --- p.62 / Chapter 5.3 --- Comparison with Experiment --- p.65 / Chapter 5.4 --- Comparison with Rayleigh Scattering Model --- p.71 / Chapter 5.5 --- Summary --- p.74 / Chapter 6 --- A Method of Obtaining Radiative Decay Rates From Experiment --- p.76 / Chapter 6.1 --- Introduction --- p.76 / Chapter 6.2 --- Method --- p.77 / Chapter 6.3 --- Prove of Validity --- p.78 / Chapter 6.4 --- Experimental Demonstration --- p.82 / Chapter 6.5 --- Summary --- p.85 / Chapter 7 --- Conclusion --- p.86 / Chapter 8 --- Bibliography --- p.88 / Chapter 9 --- Curriculum Vitae --- p.93

由於表面等離子體激元可以將電磁場限制在金屬表面，從而產生強烈的場強增強效果，因此在納米光子學和生物光子學方面具有廣泛的應用價值，其中包括高性能發光二級管、光伏電池、超高分辨率光學成像和超靈敏分子檢測等。尤其在單分子和醫學診斷方面，基於表面等離子體共振的生物傳感器獲得了越來越多的青睞。本論文包括兩部份。第一部份著重討論二維週期性洞陣列的表面等離子體特性，而第二部份則是研究這種洞陣列結構在表面等離子體共振傳感方面的應用。 / 在第一部份中，表面等離子體模式被分為非簡並模式(m，O) 和簡並模式(m，±n)兩種情況分別加以討論。首先，結合實驗結果和理論模型，我們對非簡並模式的衰減壽命和激發效率進行了研究。通過光干涉光刻法和薄膜沉積技術，一系列不同幾何結構的洞陣列樣品被製備出來，且這些樣品具有很高的重複性。利用角分辨色散關係進行模式識別以及確定這些模式的衰減壽命和激發效率。通過調整起偏器和檢偏器的相對方向，表面等離子體模式的非輻射和輻射衰竭均可加以研究。結果發現，衰減壽命強烈依賴於單洞的幾何結構，而且這種行為可以用簡單的靜電模型并考慮高階修正加以解釋。從非輻射衰減和輻射衰減平衡的角度出發，激發效率對幾何結構和共振波長的依賴性也可以理解。對於簡并模式，由於存在稱合，對稱模式和反對稱模式分別被p 偏振激發和S偏振激發。它們的對稱性和對於衰減壽命和共振波長的修正可以用干涉法和模式耦合理論來理解。最後，利用多模耦合方程，我們對色散關係圖譜隨著洞深度增加而演化的情況也進行了探討。 / 第二部份對基於表面等離子體共振的生物傳感器與陣列幾何結構的關係進行了研究。結果發現，激發效率和衰減壽命對表面等離子體共振傳感器的分辨率都起到了關鍵性作用。在共振中，峰值高度和帶寬主要由表面等離子體的衰減速率控制。較低的衰減速率導致較清晰的峰值線型，從而產生較高的傳感器分辨率。因此，通過調整陣列的幾何結構以產生非常低得輻射衰減速率，表面等離于體共振傳感器的品質因數可高達104.8/RIU ，這已經超過了基於梭鏡和納米粒子對應器件的性能表現。 / Surface plasmon polaritons (SPPs) generate a strong localized electromagnetic field on metal surface and thus are promising for nano- and bio-photonics including high performing light-emitting diodes and photovoltaic cells, super-high resolution optical imaging, ultra-high sensitive bimolecular detection, etc. In particular, the application of SPPs on surface plasmon resonance (SPR) biosensor has drawn much more attention recently because of the attempt to realize single molecule detection in medical diagnosis. / This thesis contains two parts. The first part focuses on studying the basic plasmonic properties of two-dimensional periodic hole arrays while the second part concentrates on the application of hole arrays on SPR sensing. / In the first part, SPPs modes on hole arrays are classified into nondegenerate mode (m, 0) and degenerate mode (m, ±n). For nondegenerate mode, its decay lifetime and generation efficiency are studied both experimentally and theoretically. By combining interference lithography and thin film deposition, a set of arrays with a wide range of geometry has been fabricated with high reproducibility. The dispersion relations of arrays are studied by angle-dependent reflectivity for mode identification and detenninations of SPP decay lifetime and generation efficiency. In particular, through orienting the polarization of the specular reflection either parallel or orthogonal to that of the incidence, we can access both the nonradiative and radiative decays of SPPs at different resonance wavelengths. As a result, it is found that decay lifetime is strongly dependent on the geometry of single hole and its behaviors can be understood by using a simple quasi-static model taking into account of the higher order correction as well as numerical simulation deduced by finite-difference timedomain. The dependence of generation efficiency on hole geometry or resonance wavelength can be understood in tenns of trade-off between nonradiative and radiative decay rates. Once these two decay rates equals to each other, the optimum generation efficiency is realized and the field enhancement gets the maximum. And the optimum parameters can be achieved by adjusting the hole geometry or the resonance wavelength. For degenerate mode, due to the coupling between (m, +n) and (m, -n) modes, a symmetric and an anti-symmetric modes are excited under pand s-polarized excitation, respectively. Their symmetries and modifications to the decay lifetime and resonance wavelength can be understood by using the interference method and coupled mode theory. Finally, generalized coupled mode equations are employed to know about the evolution of dispersion relation as hole depth increases. / The dependence of SPR biosensor on the generation and decay of SPPs are studied in the second part. Both the generation efficiency and decay lifetime of SPPs are found to be critical in governing the resolution of SPR biosensor. In SPR, the peak height and linewidth are primarily controlled by the decay rate of SPPs. Lower decay rate leads to sharper peak profile, which results in higher SPR resolution. Therefore, by tailoring the geometry of hole arrays to achieve a very low radiative decay rate, a SPR biosensor with figure of merit (FOM) reaching l04.8/RIU can be realized, which surpasses those of prism and nanoparticle counterparts. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Zhang, Lei = 表面等離子體激元對於週期性金屬納米結構幾何形狀的依賴性及其在生物傳感中的應用 / 張磊. / "November 2011." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 116-125). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Zhang, Lei = Biao mian deng li zi ti ji yuan dui yu zhou qi xing jin shu na mi jie gou ji he xing zhuang de yi lai xing ji qi zai sheng wu chuan gan zhong de ying yong / Zhang Lei. / Chapter Chapter1 --- Introduction --- p.1 / Chapter Chapter2 --- Theoretical Background --- p.7 / Chapter 2.1 --- Maxwell's equations --- p.7 / Chapter 2.2 --- Classic electromagnetic theory for dielectric properties of matter --- p.9 / Chapter 2.3 --- Surface plasmon polaritons at the dielectric/metal interface --- p.11 / Chapter 2.4 --- Excitation of surface plasmon polaritons --- p.16 / Chapter 2.4.1 --- Prism coupling --- p.17 / Chapter 2.4.2 --- Grating coupling --- p.17 / Chapter 2.5 --- lones calculus --- p.19 / Chapter 2.6 --- Finite-difference time-domain method --- p.22 / Chapter Chapter 3 --- Sample Preparation --- p.25 / Chapter 3.1 --- Interference lithography --- p.25 / Chapter 3.1.1 --- Substrate preparation --- p.26 / Chapter 3.1.2 --- Exposure --- p.27 / Chapter 3.1.3 --- Pattern development --- p.30 / Chapter 3.2 --- Thin film deposition --- p.30 / Chapter Chapter 4 --- Experimental Setups and Calibration --- p.33 / Chapter 4.1 --- Experimental setup for measuring dispersion relation --- p.33 / Chapter 4.2 --- Experimental setup calibration --- p.35 / Chapter 4.2.1 --- Calibration of spectrometer --- p.36 / Chapter 4.2.2 --- Calibration of movement stages --- p.38 / Chapter 4.3 --- Data presentation for dispersion relation --- p.40 / Chapter 4.4 --- Summary --- p.41 / Chapter Chapter 5 --- Understanding of Fundamental Properties of SPPs --- p.43 / Chapter 5.1 --- Excitation of SPPs on 2D hole arrays --- p.44 / Chapter 5.2 --- Properties of non degenerate modes and theoretical explanation --- p.53 / Chapter 5.2.1 --- Dependence of lifetime on hole geometry and theoretical explanation --- p.55 / Chapter 5.2.2 --- Dependence of generation efficiency on hole geometry and theoretical explanation --- p.63 / Chapter 5.3 --- Properties of degenerate modes and theoretical explanation --- p.70 / Chapter 5.3.1 --- Dependence of properties of degeneration modes on hole geometry by FDTD --- p.72 / Chapter 5.3.1.1 --- (0, ±l)[subscript s,a] modes --- p.72 / Chapter 5.3.l.2 --- (-1, ±l)[subscript s,a] modes --- p.76 / Chapter 5.3.2 --- Understanding of excitation of degenerate modes by using interference method --- p.79 / Chapter 5.3.3 --- Understanding of coupling between degenerate modes by using coupled mode theory --- p.85 / Chapter 5.4 --- Evolution of dispersion relation as hole depth increases --- p.90 / Chapter 5.5 --- Summary --- p.95 / Chapter Chapter 6 --- Surface Plasmon Resonance Based Label Free Biosensor --- p.98 / Chapter 6.1 --- Basics of surface plasmon resonance (SPR) based biosensor --- p.98 / Chapter 6.2 --- State-of-the-art SPR biosensor --- p.101 / Chapter 6.3 --- SPR biosensor by using 2D metallic hole arrays --- p.102 / Chapter 6.4 --- Summary --- p.111 / Chapter Chapter 7 --- Conclusions --- p.112 / References --- p.116 / Publications --- p.126

Total scattering can be used to study crystalline materials, whose structure presents a periodic arrangement of atoms, as well as disordered materials, such as liquids, glasses or nanomaterials. This thesis work reports three experimental case studies in which different analysis methods were chosen as appropriate on a case-by-case basis. This study demonstrates that total scattering combined with modelling and complementary experimental techniques can guide the understanding of the structure of complex nanostructures. X-ray and neutron total scattering data were collected on multi-walled carbon nanotubes continuously filled with iron and analysed using the program PDFgui for refinement of the pair distribution function and molecular dynamics simulations using the program DL_Poly_4. The analyses show that the iron core is mainly composed of ��-Fe and confirms the dependence of the local ordering on the orientation of the crystallographic axes of iron with respect to the nanowire axis. Prussian blue (Fe4[Fe(CN)6]3 · ��H2O) was synthesised in bulk and nanoparticulate phases using deuterated chemicals; the amount of D2O and H2O in the pores and vacancies, as well as polyvinylpyrrolidone remaining in the nanoparticle samples, were estimated, using an ad hoc modelling procedure of the first few peaks in the neutron PDF function. Models of the structure were refined using the programs PDFgui and RMCProfile. In the last case, a 50Å supercell of the bulk structure with randomly distributed stoichiometric vacancies and D2O and H2O molecules occupying both the pores and the vacancies was used as starting atomic configuration. The CaO/CaCO3 family of materials consists of a series of samples that have undergone carbonation and/or calcination. The X-ray and neutron pair distribution function data were compared to the theoretical PDF of the CaO and CaCO3 phase, generated using the program GULP, that produces PDF functions based on the spectrum of phonon frequencies of the material. The analysis shows that the carbonation is almost completed already after 2 minutes of carbonation and the structure remains stable under further carbonation.

One of the objectives of nanotechnology is to develop ways to build functional nanoscale devices from nanostructures. Whether these nanodevices will constitute the basis for new technologies rests on the ability to precisely manipulate the nanostructures in such a way that large numbers of functional devices can be built in parallel, with each nanodevice precisely located and addressed. In this work nanostructures dispersed in solution are organized onto surfaces by means of molecular-scale directed assembly. This technique combines top down high resolution lithographic patterning to bottom up self-assembly: specific molecular interactions take place at locations precisely defined by lithography, resulting in the parallel assembly of an arbitrarily large number of devices into complex and precisely ordered arrangements. While different molecules are used in this study, DNA plays a key role throughout the work due to the specificity of its interactions, its programmability and outstanding chemical flexibility. Two approaches are developed to direct the assembly of nanostructures on a surface. The first involves the patterning and selective functionalization of metallic nanodots that are used as anchors for the attachment of DNA molecules, proteins, DNA nanostructures and single-wall carbon nanotube (SWCNT) segments wrapped by DNA. Different strategies are explored to maximize the yield of the desired assembly. This platform also allows the monitoring of DNA-protein interactions with single molecule resolution, which has many potential biomedical applications. In the second approach, lithographic patterning is used to define regions of high surface energy that promote the binding of DNA origami and SWCNT segments. The high patterning resolution again allows for single nanostructure manipulation. This method facilitates the assembly of SWCNT field effect transistors from DNA-wrapped SWCNT segments. The formation of multi-component nano-objects in solution, by directing the linkage of properly functionalized nanostructures, is also studied. The products of these reactions are suitable for surface placement with the developed directed assembly techniques, thereby resulting in a hierarchical directed assembly process. Among others, the synthesis of SWCNT-dsDNA heterostructures is described. These hybrid objects can be used to electrically probe dsDNA using the SWCNTs as electrodes, by assembling solid state devices by means of the directed assembly methods, and also by conductive AFM. The results of some electrical measurements of double stranded DNA are discussed. The techniques developed in this thesis are directly applicable to fundamental studies of electron transport in molecules and other nanostructures, but they also have utility in other fields, such as chemistry and biology, where single molecule resolution is required. In addition, the approaches developed in this work may facilitate the advancement of new electronics technologies, including, but not limited to, future circuits based on single-wall carbon nanotubes with specific electronic properties.

Etanol é um combustível químico promissor como uma fonte de geração de energia in situ para a aplicação em células a combustível de baixa temperatura (25 °C). Entretanto, o desenvolvimento das células a combustível utilizando etanol no ânodo têm sido prejudicado devido à baixa eficiência na oxidação eletroquímica do etanol para dióxido de carbono. Com isso, esta tese tem como objetivo sintetizar novos eletrocatalisadores nanoestruturados e investigar a sua atividade catalítica para a eletro-oxidação do etanol; além de avançar no conhecimento do mecanismo reacional envolvido. Para o estudo em eletrólito ácido, os eletrocatalisadores foram formados por nanoestruturas do tipo casca-núcleo, core-shell, constituída de uma casca de Pt sobre núcleos de Rh, Cu e Ni, e de nanoestruturas de Pt com núcleo oco, hollow. Para o eletrólito alcalino, os catalisadores foram formados por eletrodos policristalinos de Pt, Pd e Rh. Os produtos reacionais formados durante a eletro-oxidação do etanol nos diferentes eletrocatalisadores foram monitorados por medidas de espectrometria de massas on-line, Differential Electrochemical Mass Spectrometry - DEMS. Os resultados de DEMS on-line revelaram que o catalisador constituído de uma nanoestrutura de Pt depositada sobre um núcleo de Rh/C, com recobrimento em torno de 70 %, apresentou uma maior eficiência de conversão eletroquímica do etanol para CO2 quando comparado com o eletrocatalisador de Pt/C. Neste caso, os átomos de Rh expostos atuaram como sítios atívos para a adsorção dissociativa do etanol. Por outro lado, o eletrocatalisador constituído de uma casca de Pt e uma estrutura oca no núcleo mostaram maiores taxas reacionais globais de oxidação do etanol quando comparado com o eletrocatalisador de Pt/C, o que foi atribuído à menor força de adsorção do etanol e dos intermediários formados sobre a superfície metálica. Isso é devido ao menor valor de energia (εd) do centro da banda d da Pt, que é causado pela contração da rede cristalina da Pt, devido à formação de uma nanoestrutura oca no núcleo (Efeito geométrico), e pela interação eletrônica dos átomos de Pt superficiais com átomos de Ni remanescentes nas camadas mais internas da nanopartícula (Efeito ligane). Os resultados em eletrólito alcalino mostraram que o eletrocatalisador de Pt apresenta a maior taxa reacional global de oxidação do etanol quando comparado com os eletrodos policristalinos de Pd e Rh. Os experimentos de DEMS on-line, por outro lado, mostraram que o Rh apresenta uma maior eficiência de conversão eletroquímica do etanol para CO2 e o Pd catalisa a reação, preferencialmente, pela via de formação de ácido acético. Além disso, o eletrodo policristalino de Pd revelou que a produção de CO2 ocorreu predominantemente por uma via divergente à observada para os eletrodos de Pt e Rh. Contudo, o entendimento do mecanismo de reação envovido e das propriedades eletrocatalíticas podem propulsionar, futuramente, a comercialização generalizada das células a combustível de etanol direto. / Ethanol is a promissing chemical fuel as an in situ source of energy generation for low-temperature fuel cells application (25 °C). However, due to the dominance of the paralell reaction pathway, the development of direct ethanol fuel cells (DEFC) has been impeded by the low activity of existing electrocatalysts for oxidizing ethanol to CO2. Based on this, the thesis aims to synthesize novel nanostructured electrocatalysts for ethanol electro-oxidation, besides deeper understanding of the reaction mechanism which takes place. The ethanol electro-oxidation reaction (EOR) was studied in acid electrolyte on carbon-supported core-shell electrocatalysts, consisting of Pt shell on Rh, Cu and Ni cores or on hollow-core nanostructure. On the other hand, in alkaline electrolyte, the reaction was investigated on electrodeposited polycristallines Pt, Pd, Rh electrodes. The reaction products during EOR on differents electrocatalysts were monitored by means of on-line DEMS (Differential Electrochemical Mass Spectrometry) measurements. By on-line DEMS measurements, the Pt1.0/Rh/C electrocatalysts revealed the highest efficiency for oxidizing ethanol to CO2 in acid electrolyte, which was ascribed to its faster and more extensive ethanol deprotonation on the Pt-Rh sites, producing adsorbed intermediates in which the C-C bond cleavage is facilitated. On the other hand, potentiodynamic and potentiostatic curves showed the higher overall reaction rate for ethanol oxidation on Pt hollow nanostructure than that observed for Pt1.0/Rh/C and commercial Pt/C electrocatalysts, which might be attributed to the weaker adsorption strength of ethanol and intermediate species, such as CO and CHx. This improvement is achieved by the hollow-induced lattice contraction (Geometric effect) and the presence of Ni atoms located at the underneath Pt shell (Electronic effect). Both of these structural features may result in a decrease of the Pt 5d-band center - a great way for enhancing both the catalysts\' activity and Pt mass activity for ethanol oxidation in acid fuel cells. In the case of ethanol electro-oxidation in alkaline electrolyte, the results showed that the highest overall reaction rate occurred on Pt electrocatalyst when compared with polycrystalline Pd and Rh electrodes. On-line DEMS experiments revealed that the polycrystalline Rh electrode exhibited greater efficiency for oxidizing ethanol to CO2, but Pd showed higher amounts of acetic acid (ethylacetate). Furthermore, in the case of Pt and Rh electrocatalysts, the CO2 formation proceeded via the COad and CHx,ad species oxidation, however, on Pd electrode, the reaction occured via a divergent pathway. Therefore, a deeper understanding for both catalysts\' activity and reaction mechanism seems to be a promising way for resolving the major obstacles to the widespread commercialization of low-temperature fuel cells.

Chow Chi Fai. / Thesis submitted in: August 2005. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references. / Abstracts in English and Chinese. / Abstract / Abstract (Chinese) / A cknowledgements / Table of Contents / List of Figures / List of Tables / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- The need for light emission from silicon --- p.1-1 / Chapter 1.2 --- Silicon-based light emitting material 1 - --- p.2 / Chapter 1.3 --- Literature overview --- p.1-4 / Chapter 1.4 --- Project goal --- p.1-10 / Reference --- p.1-11 / Chapter Chapter 2 --- Experimental details / Chapter 2.1 --- Introduction --- p.2-1 / Chapter 2.2 --- Sample preparation techniques --- p.2-1 / Chapter 2.2.1 --- MEVVA ion implantation --- p.2-1 / Chapter 2.2.2 --- PL samples preparation conditions --- p.2-3 / Chapter 2.2.3 --- EL samples preparation conditions --- p.2-4 / Chapter 2.3 --- Characterization techniques --- p.2-7 / Chapter 2.3.1 --- Photoluminescence spectroscopy (PL) --- p.2-7 / Chapter 2.3.2 --- Electroluminescence spectroscopy (EL) --- p.2-9 / Chapter 2.3.3 --- Rutherford backscattering spectroscopy (RBS) --- p.2-10 / Chapter 2.3.4 --- X-ray diffraction (XRD) --- p.2-12 / Chapter 2.3.5 --- Transmission electron microscopy (TEM) --- p.2-13 / Reference --- p.2-15 / Chapter Chapter 3 --- Resutls and Discussions / Chapter 3.1 --- RBS results --- p.3-1 / Chapter 3.2 --- XRD results --- p.3-8 / Chapter 3.3 --- TEM results --- p.3-12 / Chapter 3.3.1 --- Effects of the implantation energy on the microstructure of samples --- p.3-13 / Chapter 3.3.2 --- Effects of the implantation dose on the microstructure of samples --- p.3-16 / Chapter 3.4 --- Photoluminescence results --- p.3-19 / Chapter 3.4.1 --- Effect of implantation energy on the PL --- p.3-19 / Chapter 3.4.2 --- Effect of FA temperature on the PL --- p.3-24 / Chapter 3.4.3 --- Effect of FA duration on the PL --- p.3-26 / Chapter 3.4.4 --- Effect ofRTA duration on the PL --- p.3-28 / Chapter 3.4.5 --- Effect ofRTA temperature on the PL --- p.3-30 / Chapter 3.4.6 --- Effect of implantation dose on the PL --- p.3-32 / Chapter 3.4.7 --- Si band edge enhancement --- p.3-34 / Chapter 3.4.8 --- Photoluminescence spectra as a function of excitation power density --- p.3-37 / Chapter 3.4.9 --- Photoluminescence spectra as a function of measurement temperature --- p.3-45 / Chapter 3.5 --- Electroluminescence results --- p.3-52 / Chapter 3.5.1 --- EL quantum efficiency --- p.3-60 / Reference --- p.3-61 / Chapter Chapter 4 --- Conclusion and future works / Chapter 4.1 --- Conclusion --- p.4-1 / Chapter 4.2 --- Future works --- p.4-2 / Appendix I / Appendix II

基於表面等離子體的納米器件已經在近幾十年引起了十分廣泛的興趣因為其對於半波長光子器件，光學傳感，光譜學以及光學捕獲有著廣大的應用前景。表面等離子體是一種被限定於金屬和介質介面上的一種光子-電子混合模式，而且它具有許多吸引人的特質，比如對金屬表面周圍環境極其敏感，納米尺度範圍的光學電磁場局域和場增強，以及對鄰近物體極強的場強梯度捕獲力。雖然這些特性都已經分別被廣泛的研究過，但從光學捕獲的角度去實現光學傳感的方案並還沒有引起大量的關注。很明顯，在納米尺度範圍內操縱目標的可能性將使得新的納米器件具有高的光學探測性能和多功能性。為了涉及這個論題，本項目包括新穎的等離子體納米器件的研究，這些納米器件將能夠提供獨特的功能，在光學傳感，表面增強拉曼散射，以及光學捕獲方面。 / 在第一部分設計中，構建了一種基於雙層金屬納米條陣列的耦合系統。這樣的系統具有簡單的結構，易於加工和集成於微流系統的優點。由於這個系統內的光場耦合，場強可以進一步的被加強，這樣的特點有助於提高系統的敏感特性，尤其是通過強的光場來捕獲一些金屬的納米顆粒後。這個系統的光學共振條件可以從理論上進行模式分析得到。然後二維時域有限差分法證實了理論的分析而且進一步證明了利用該系統於光學傳感和捕獲的可能性。結果表明此系統的光學敏感度約為200nm/RIU，通過光學捕獲的金屬納米顆粒引起的近場調製和場增強可以使得表面增強拉曼散射的增強因數達到10⁹ 到10¹° 的高度。 / 在第二部分的設計裡，金納米環結構被證實了可以成為一個強大的工具作為表面等離子體納米光鑷來抓獲金屬納米顆粒。首先，金屬納米環具有很多優點比如對入射光的偏振不敏感，很寬的可調的共振範圍，有環的內腔周圍和內部有著均勻的光學場增強，以及很容易製備。這裡的設計著重于納米環在入射波長為785nm 的新穎的光學捕獲特性以及表面增強拉曼散射的性能。三維的時域有限差分法被用來計算結構的光學回應，以及麥克斯韋應力張量法被用來計算光學受力分佈情況。計算結果表明對於一個有20nm 大小的金納米顆粒球，納米環結構有最大的光學捕獲勢阱約32 KgT 。由於納米環結構周圍存在多個捕獲勢阱，使得其對目標捕獲顆粒具有約10⁶nm³ 的非常之大的有效體積。而且，被捕獲的顆粒會進一步的導致一些納米間隙的形成，這些納米間隙又會使得近場增強達到約160 倍的高度，這使得在實際應用中10⁸ 的表面增強拉曼散射的增強因數成為可能。 / 在第三部分的設計裡，全光納米操縱的概念被提出並證實，因為這樣的概念拓展了等離子體光鑷的一個極其重要的功能，那就是被捕獲的分子可以在捕獲和區域內被任意的操縱和轉移，而且這個區域是納米尺度的。設計的系統由梯度形金屬納米盤組成，這些納米盤具有不同的直徑，這使得它們支援不同波長的表面等離子體共振。通過改變入射光的波長和旋轉入射光的偏振態，就可以將捕獲的目標從一個納米盤轉移到另一個納米盤。三維的時域有限差分法和麥克斯韋應力張量法被用來證實了所提出的觀點。計算結果表明被捕獲的目標感受到的捕獲勢阱深度高達5000kgT/W/μm²，最大的光學轉矩約為336pN·nm/W/μm²，而且總的有效捕獲體積可達到10⁶nm³ 。在這部分的結尾，討論了所設計的系統在光學傳感方面潛在的應用前景。 / 在最後的部分裡，展示了一個實驗的證明來說明等離子體納米光鑷對目標捕獲的觀測問題，因為這樣的觀測對往後近期的相關實驗來說是首先要關心的問題。雖然兩種途徑已經在別處被證實了，分別是通過觀測系統的透射光的強度變化和系統共振波長的改變，來監測表面等離子體納米光鑷近場捕獲行為的發生，但是在這個部分裡，等離子體納米光鑷和表面增強拉曼傳感技術被結合在了一起並且被證實了這是另一種有效的方法用於觀測捕獲行為的發生。在本實驗中兩束鐳射光束被為別用來激發等離子體納米光鑷和表面增強拉曼信號，一束是633nm 的鐳射，另一束是785nm 的鐳射。表面等離子體納米光鑷簡單地由熱蒸鍍並熱退光的金顆粒納米島墊底構成，這個墊底的共振峰被調製到緊靠633nm 的位置。目標顆粒是由光化學生長合成的銀納米十面體，這些十面體被綁定了4-巰基苯甲酸分子的單分子層，且具有遠離633nm 和785nm 的共振峰。由於當等離子體納米光鑷被激勵的時候目標顆粒會被捕獲到近場的熱點內，這時近場的光場就會被極大的增強，所以表面增強拉曼的信號就會出現。這個過程也被用數值模擬的方法（三維時域有限差分法和麥克斯韋應力張量法）闡明了。更進一步的，當等離子體納米光鑷不被激勵的時候，被捕獲的目標顆粒可以被釋放掉，那樣表面增強拉曼的信號就會消失掉。所以，本設計不僅提供了一種強有力的探測等離子體光鑷捕獲行為的方法，而且能夠成為一種在生物探測方面可重複利用的“捕獲并傳感“的平臺。 / Surface plasmons (SPs) based nanodevices have attracted much research interest in recent decades due to their powerful application potentials for subwavelength optical circuits, optical sensing, spectroscopy, and optical trapping. SPs are the hybrid photon-electron modes bound at the interface of conductors and transparent materials, and they have lots of attractive properties such as sensitive to the changes of environment around the interface, strong optical field localization and enhancement in nanoscale domain, and strong field intensity gradient forces to trap the adjacent objects. Even though these properties have been widely investigated, their application in optical sensing based on the plasmonic optical trapping strategy remains largely unexplored. Clearly, the possibility of manipulating objects within the nanometer regime will enable new nanodevices that offer high optical detection performance and multiple-functionality. With the aim to address this issue, this project involves the study of novel plasmonic nanodevices that provide unique functionality in optical sensing, surface-enhanced Raman scattering (SERS), and optical trapping. / The first design is based on a coupling system involving double-layered metal nano-strips arrays. This system has the advantages of simple geometry and direct integration with microfluidic chips. The intense optical localization due to field coupling within the system can enhance detection sensitivity of target molecules, especially by virtue of the optical trapping of plasmonic nanoparticles. The optical resonant condition is obtained theoretically through analyzing the SPs modes. Numerical modeling based on two-dimensional (2D) finite-difference time-domain (FDTD) is consistent with the theoretical analysis and demonstrates the feasibility of using this system for optical sensing and trapping. Simulation results show that the refractive index sensitivity can reach ~200 nm/RIU, and a maximum SERS enhancement factor (EF) of 10⁹-10¹° is possible because of the near-field modulation and enhancement from optically trapped metal nanoparticles. / In the second design, a gold nano-ring structure is demonstrated to be an effective approach for plasmonic nano-optical tweezers (PNOTs) for trapping metallic nanoparticles. The plasmonic nano-ring structure has many interesting merits such as polarization insensitivity, wide tunable resonance range, uniform field enhancement around and inside the ring cavity, and ease of fabrication. This design has a unique feature of having large active volume for trapping. In our demonstration example, we have optimized a device for SERS operation at the wavelength of 785 nm. Three-dimensional (3D) FDTD techniques have been employed to calculate the optical response, and the optical force distribution have been derived using the Maxwell stress tensor (MST) method. Simulation results indicate that the nano-ring produces a maximum trapping potential well of ~32 kgT on a 20 nm gold nanoparticle. The existence of multiple potential well results in a very large active trapping volume of ~10⁶ nm³ for the target particles. Furthermore, the trapped gold nanoparticles further lead to the formation of nano-gaps that offer a near-field enhancement of ~160 times, resulting in an achievable EF of 10⁸ for SERS. / In the third design, we propose a concept of all-optical nano-manipulation. We show that target molecules, after being trapped, can be transferred between the trapping sites within a linear array of PNOTs. The system consists of an array of graded plasmonic nano-disks (NDs) with individual elements coded with different resonant wavelengths according to their dimensions. Thus, by switching the wavelength and rotating the polarization of the excitation source, the target nanoparticles trapped by the device can be manipulated from one ND to another. 3D FDTD simulation and MST calculation are utilized to demonstrate the operation of this idea. Our results reveal that the target experiences a trapping potential strength as high as 5000 kgT/W/μm², maximum optical torque of ~336 pN·nm/W/μm², and the total active volume may reach ~10⁶ nm³. The potential applications in terms of optical sensing are also discussed. / In the final design, for which experimental demonstration has been conducted, we show that PNOTs are achievable with random plasmonic nano-islands. Operation of the random PNOTs can be monitored by measuring the SERS enhancement factor in real time. Two laser beams having wavelengths of 633 nm and 785 nm are utilized to stimulate the PNOTs and excite the Raman signals simultaneously. The PNOTs are formed by annealing of a thermal evaporated gold film. This so-called nano-island substrate (Au-NIS) has a resonant peak close to 633 nm. The target is photochemical synthesized silver nanodecadedrons (AgNDs) functionalized with 4-Mercaptobenzoic acid (4-MBA) and the resonant peak of these AgNDs is far away from 633 nm and 785 nm. As the target is trapped to the hot-spots when the PNOTs are active, the near-field intensity is enhanced significantly, which results in the emergence of SERS signals, i.e. confirming the expected outcome of SERS upon nanotrapping by the PNOTs. This process is also elucidated numerically through 3D FDTD simulation and MST calculation. Furthermore, the target can be released as the PNOTs become inactive, i.e. disappearance of the SERS signal. Therefore, this design offers not only a robust avenue for monitoring trapping events in PNOTs, but also a reproducible “trap-and-sense“ platform for bio-detection. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Kang, Zhiwen. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 146-170). / Abstracts also in Chinese. / Abstract --- p.I / Acknowledgements --- p.VIII / List of Illustrations --- p.XIII / Chapter Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Surface Plasmon Polaritons and Localized Surface Plasmons --- p.1 / Chapter 1.2 --- Relevant Applications Based on Surface Plasmons --- p.3 / Chapter 1.3 --- Plasmonic Nano-Optical Tweezers and Relevant Applications --- p.7 / Chapter 1.4 --- Literatures Review and Objectives of this Thesis --- p.12 / Chapter 1.5 --- Structure of this Thesis --- p.17 / Chapter Chapter 2. --- Research Methodologies --- p.20 / Chapter 2.1 --- Theoretical Background of Surface Plasmons --- p.20 / Chapter 2.2 --- Numerical Simulation Techniques for Studying Complex Nanostructures --- p.30 / Chapter 2.3 --- Optical Force Calculation with the Maxwell Stress Tensor Method --- p.38 / Chapter 2.4 --- Nanostructure Fabrication and Characterization --- p.40 / Chapter Chapter 3. --- Optical Sensing Based on Double-Layered Metal Nano-Strips --- p.43 / Chapter 3.1 --- Introduction --- p.43 / Chapter 3.2 --- Theoretical Model and Analysis --- p.46 / Chapter 3.3 --- Numerical Verification and Discussion --- p.50 / Chapter 3.4 --- Optical Sensing Evaluation --- p.54 / Chapter 3.5 --- Near-Field Modulation by Optically Trapped Metal Nanoparticles --- p.58 / Chapter 3.6 --- Discussion --- p.61 / Chapter 3.7 --- Conclusion --- p.62 / Chapter Chapter 4. --- Gold Nano-Ring as Plasmonic Nano-Optical Tweezer --- p.64 / Chapter 4.1 --- Introduction --- p.64 / Chapter 4.2 --- Design and Optical Response --- p.67 / Chapter 4.3 --- Optical Force Calculation and Evaluation of Trapping Performance --- p.73 / Chapter 4.4 --- Stable Trapping Sites and Active Trapping Volume --- p.76 / Chapter 4.5 --- Near-Field Variation and Discussion --- p.81 / Chapter 4.6 --- Conclusion --- p.84 / Chapter Chapter 5. --- Graded Plasmonic Nano-Disks for Near-Field Nano-Manipulation --- p.86 / Chapter 5.1 --- Introduction --- p.86 / Chapter 5.2 --- Modeling and Optical Response --- p.89 / Chapter 5.3 --- Optical Force Distribution in the Structure --- p.91 / Chapter 5.4 --- Optical Trapping Potential and Rotational Energy --- p.96 / Chapter 5.5 --- Optical Trapping Volume and Discussion --- p.101 / Chapter 5.6 --- Conclusion --- p.104 / Chapter Chapter 6. --- Monitoring Plasmonic Nano-Optical Trapping through Detection of Surface-Enhanced Raman Scattering --- p.106 / Chapter 6.1 --- Introduction --- p.106 / Chapter 6.2 --- Numerical Investigation --- p.110 / Chapter 6.3 --- Sample Preparation and Characterization --- p.112 / Chapter 6.4 --- Experimental Implementation and Results --- p.122 / Chapter 6.5 --- Discussion --- p.134 / Chapter 6.6 --- Conclusion --- p.137 / Chapter Chapter 7. --- Conclusion and Outlook --- p.139 / References --- p.146 / Publications from this Work --- p.171

By combining experiment and theory, we believe our study shed light on developing a new method for well investigating and controlling the different plasmonic modes and open their way for some great applications in biology, chemistry and photonics. / Finally, this thesis presents an approach to quantitatively evaluate the SP-mediated light emission. Based on this consideration, efforts are taken to find the temperature effect of SP on the light emission in semiconductor. On metal/ZnO system, a more realistic picture for the light emission is depicted by experimentally measuring the temperature-dependent photoluminescence and theoretically calculating the Purcell enhancement factor. The increasing plasmonic density of states with the lower temperature has been regarded as being responsible for the enhanced light emission. / Firstly, studies are performed on finding an in-depth understanding into the optical properties of two-dimensional (2D) metallic nano-cavity structure (grating). Structures are fabricated by interference lithography and thin film techniques. Grating geometries can be easily tuned by using these versatile techniques with high reproducibility and precision. Plasmonic dispersion in the 2D grating has been mapped out by angle-dependent reflectivity measurements. Two particular nanostructures, i.e., nano-bottle array and elliptical hole array, have been chosen to investigate the dependence of plasmonic properties on geometries change. Theories are also put forward to understand the origin and electromagnetic properties of the obtained plasmonic modes. / Surface plasmons (SP), the collective oscillations of the conduction electrons between the metal/dielectric interface, strongly influence the optical properties of metallic nanostructures and are of great interest for future photonic devices. Here, this thesis mainly focuses on the experimental and theoretical investigations on the optical properties of the metallic periodic nanostructures. / With an understanding into the different plasmonic properties of the metallic nanostructures, researches are then undertaken to explore how this associated electromagnetic field interacts with the molecules adsorbed onto a sample surface. The distinct and strong correlation between the plasmonic modes and surface enhanced Raman scattering (SERS) is verified on the one-dimensional silver grating. In particular, the detailed analysis of the enhancement factor from surface plasmons excitation and de-excitation process in SERS has been performed. On the other hand, the technique used to fabricate the controllable "hot spot" for enhancing Raman scattering has been introduced on the 2D metallic grating. Complemented by the theoretical simulation, the conditions for optimizing SERS enhancement effect are proposed. / Li, Jia = 週期性金屬鈉米結構光學特性的實驗和理論研究 / 李佳. / Adviser: Ong Hock Chun. / Source: Dissertation Abstracts International, Volume: 71-01, Section: B, page: 0388. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 135-144). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / Li, Jia = Zhou qi xing jin shu na mi jie gou guang xue te xing de shi yan he li lun yan jiu / Li Jia.

I believe that my research work on the plasmonic spectroscopy of metallic nanostructures has provided an in-depth fundamental understanding of the localized surface plasmon resonance and will have a number of implications for the applications of metallic nanostructures in optics, optoelectronics, and biotechnology. / I will first describe my studies on the plasmonic properties of metallic nanostructures. Specific approaches of modifying the sizes and shapes of Au nanorods have been developed for tailoring their plasmonic properties, including surface plasmon wavelength, absorption, scattering, and extinction cross sections. Single-particle dark-field imaging and spectroscopy have proved that the scattering intensity of overgrown nanorods is larger than that of shortened nanorods from the same starting nanorods. Finite-difference time-domain (FDTD) calculations further show that the scattering-to-extinction ratio increases linearly as a function of the diameter of Au nanorods with a fixed aspect ratio. To obtain a deep understanding on the shape dependence of the localized surface plasmon resonance, I have emplyed FDTD on both Au nanorods and Au nanobipyramids. The results show that, when excited at their LSP wavelengths, Au nanobipyramids exhibit a maximal electric field intensity enhancement that is 3--6 times that of Au nanorods. Au nanorods have been further assembled into chains (end-to-end) and stacks (side-by-side). FDTD calculations have been performed on both Au nanorod chains and stacks with varying gap distances to obtain the dependence of the plasmon shift on the gap distance, which is then used as a plasmonic ruler to estimate the gap distance between assembled nanorods. Moreover, dye--Au nanorod hybrid nanostructures have also been successfully fabricated for the study of the coupling between the transition dipole resonance and the plasmonic resonance. The coupling-induced plasmon shift is found to be strongly dependent on molecular properties, the dye concentration in solutions, and the spacer thickness between dye molecules and the surface of Au nanorods. The coupling can be switched off by means of laser-induced photodecomposition of dye molecules. / Next, I will present my studies on the applications of metallic nanostructures. A SERS substrate has been constructed by assembling silver nanoparticles along silica nanofibers. The enhancement factors are found to be 2 x 10 5 for 4-mercaptobenzoic acid and 4-mercaptophenol, and 7 x 10 7 for rhodamine B isothiocyanate. A novel plasmonic optical fiber device has further been fabricated to detect small changes in the local dielectric environment. For individual Au nanorods, the index sensitivity and figure of merit (FOM) are found to be linearly dependent on the longitudinal plasmon resonance wavelength and reach 200 nm/RIU and 3.8, respectively. For nanorod ensembles, the index sensitivity and FOM of the longitudinal plasmon resonance are found to be 138 nm/RIU and 1.2, respectively. / The study of the plasmonic spectroscopy of metallic nanostructures is of great interest in nanoscale optics and photonics. Metallic nanostructures exhibit rich optical and electrical properties due to their localized surface plasmons (LSPs, collective charge density oscillations that are confined to metallic nanostructures). They can be widely used in a variety of application areas, such as surface-enhanced Raman scattering (SERS), plasmonic sensing, and metal enhanced fluorescence (MEF). In this thesis, a systematic study on the plasmonic spectroscopy of metallic nanostructures has been presented, both theoretically and experimentally. / Ni, Wei hai = 金屬納米結構的等離子體光譜 / 倪衛海. / Adviser: Jianfang Wang. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3580. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 135-154). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307. / Ni, Wei hai = Jin shu na mi jie gou de deng li zi ti guang pu / Ni Weihai.