在本論文中，我們利用簡單的濕化學氧化鋅(ZnO)納米線陣列模板法成功地製備了一系列具有不同化學成份、晶體結構和形貌的準一維鋅-鐵-氧納米結構陣列。 / 垂直排列的ZnO納米線陣列首先生長在不同的襯底上，然后进一步被用作其他納米結構陣列的生長模板。ZnO納米線不僅僅起到骨架定型的作用，最終還可以为后續納米結構提供原料组分。通過控制ZnO和氯化鐵溶液的反應時間，在煅燒后，我們可以製備ZnO/鐵酸鋅(ZnFe₂O₄)納米線纜陣列，以及化學/非化學計量的ZnFe₂O₄、ZnFe₂O₄/α-三氧化二鐵(α-Fe₂O₃)和α-Fe₂O₃納米管陣列。ZnFe₂O₄和α-Fe₂O₃納米管陣列都表現出了對可見光的吸收，它們的帶隙經估算分別是2.3 eV和1.7 eV。 / 通過電子能量損失譜(EELS)，可以得到ZnFe₂O₄納米管陣列的一些細節的結構信息。我們分別研究了兩個不同系列(溫度和化學計量)的ZnFe₂O₄納米管。研究發現，樣品的磁性和它們的晶體結構有著非常緊密的關係。首先，對於溫度系列的樣品，當樣品的燒結溫度從600 °C降到400 °C時，更多的三價鐵離子(Fe³⁺)佔據了尖晶石結構中的A位置(四面體位置)而並非它們本應佔據的平衡B位置(八面體位置)。這種偏離了正常尖晶石結構的情況使得A和B位置上的Fe³⁺的超交換作用增加，進而增加了樣品的阻隔溫度(TB)，磁各向異性常數(K)，3K和300 K下的飽和磁化強度(MS)和3K下的矯頑力(HC)。同時使3K和300K下的MS的比值變小。其次，對於化學計量系列的樣品，通過比較在同一燒結溫度下製備的化學計量和非化學計量的ZnFe₂O₄納米管，我們發現在鐵鋅比大於2的納米管中，Fe³⁺佔據A和B位置的比例和化學計量的樣品是类似的。這些多出的Fe³⁺也會增加超交換作用，從而導致較大的TB, K, MS(3K和300 K)，HC(3K)和較小的MS(3 K)/MS(300 K)比值。最後，作為非化學計量的極端情況，α-Fe₂O₃納米管在小的外加磁場下表現出了典型的Morin相變，在大的外加磁場下出現了場致spin-flop轉變。 / 另一方面，我們發現，當使用羅丹明B(RhB)作為指示劑時，ZnO/ZnFe₂O₄納米線纜陣列表現出了優於纯ZnO和纯ZnFe₂O₄納米管陣列的可見光降解活性，但是它們的降解路徑各不相同。ZnO由於染料敏化機制而具有可見光降解能力，但是其降解活性最差。ZnO/ZnFe₂O₄納米線纜陣列和ZnFe₂O₄納米管陣列的基本降解原理是相同的，那就是，利用有可見光活性的ZnFe₂O₄中的光生電子和空穴所生成的活性自由基降解RhB。但是，ZnO/ZnFe₂O₄納米線纜陣列的降解能力明顯優於ZnFe₂O₄納米管陣列，這是由於ZnO與ZnFe₂O₄之間的II型能帶匹配顯著地促進了光生電子和空穴的分離。 / In the present thesis, several kinds of pseudo-one-dimensional Zn-Fe-O nanostructure arrays with tunable chemical compositions, crystal structures and morphologies are successfully synthesized via a simple wet-chemical ZnO-nanowire-array templating method. / Vertically-aligned ZnO nanowire arrays are firstly fabricated on several different substrates and then serve as templates for other nanostructured arrays growth. The ZnO nanowires not only act as morphology-defining skeleton but also contribute chemically to the final composition of the nanostructures. By controlling the reaction time between ZnO and FeCl₃ solution, ZnO/ZnFe₂O₄ nanocable arrays, stoichiometric ZnFe₂O₄ nanotube arrays, nonstoichiometric ZnFe₂O₄ nanotube arrays, ZnFe₂O₄/α-Fe₂O₃ nanotube arrays and α-Fe₂O₃ nanotube arrays can be synthesized in a controlled manner after calcination. Both ZnFe₂O₄ and α-Fe₂O₃ nanotube arrays exhibit visible light absorption and their bandgap are estimated to be ~2.3 eV and ~1.7 eV, respectively. / The detailed structural information of the ZnFe₂O₄ nanotube arrays are obtained by electron energy loss spectroscopy (EELS). In particular, EELS are carried out for two different series (i.e., temperature and stoichiometric series). The magnetic properties of these samples are found to closely correlate to their structural characteristics. Firstly, with the decrease of the calcination temperature from 600 °C to 400 °C, more Fe³⁺ions occupy A sites (tetrahedral sites in spinel structure) rather than their equilibrium B sites (octahedral sites in spinel structure). The deviation from the normal spinel structure leads to the enhancement of superexchange interactions between Fe³⁺ions in A and B sites, and thus results in an increase in blocking temperature (TB), magnetic anisotropic constant (K), saturation magnetization (MS, at 3 K and 300 K), coercivity (HC, at 3 K) and a decrease in MS(3 K)/MS(300 K) ratios. Secondly, by comparing stoichiometric and nonstoichiometric ZnFe₂O₄ nanotubes calcinated at the same temperature, we found that the nonstoichiometric nanotubes (Fe:Zn > 2) shows similar ratios of Fe³⁺in A and B sites to that of the stoichiometric one. The extra Fe³⁺in the crystal also enhances the superexchange interactions of Fe³⁺, which results in larger TB, K, MS(at 3 K and 300 K) and HC(at 3 K), and smaller MS(3 K)/MS(300 K) ratio. Lastly, α-Fe₂O₃ nanotubes, as an extreme case of the nonstoichiometric sample, show typical Morin-transition characterization under small external field, and field-induced spin-flop transition at large external field. / On the other hand, we found that the visible-light-driven photodegradation activities of ZnO/ZnFe₂O₄ nanocable arrays are superior to those of the ZnO nanowire arrays and ZnFe₂O₄ nanotube arrays using RhB as the probe molecules. All the three nanostructures show degradation of RhB molecules under visible light irradiation, but they take different degradation pathways. The degradation of RhB in the presence of ZnO nanowire arrays is attributed to the dye-sensitized mechanism, and the photodegradation activity is the worst. ZnO/ZnFe₂O₄ nanocable arrays and ZnFe₂O₄ nanotube arrays have the same degradation mechanism, that is, reactive radicals produced by photogenerated electron-hole pairs in the visible-light-active ZnFe₂O₄ are responsible for the photodegradation of RhB. However, the nanocable arrays show much higher degradation capability. This is owing to the type II band alignment between ZnO and ZnFe₂O₄, which greatly promotes the separation of photogenerated electronsand holes in ZnFe₂O₄. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Guo, Xuan = 準一維鋅-鐵-氧納米結構陣列 : 控制製備, 磁學性質以及光催化方面的應用 / 郭璇. / Thesis (Ph.D.) Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 107-117). / Abstracts also in Chinese. / Guo, Xuan = Zhun yi wei xin-tie-yang na mi jie gou zhen lie : kong zhi zhi bei, ci xue xing zhi yi ji guang cui hua fang mian de ying yong / Guo Xuan.

Chan Chun Wai = 納米鈀硅合金的熱性質 / 陳進偉. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 18-20). / Text in English; abstracts in English and Chinese. / Chan Chun Wai = Na mi ba gui he jin de re xing zhi / Chen Jinwei. / Acknowledgements --- p.III / Abstract --- p.IV / 摘要 --- p.V / Chapter Chapter One ´ؤ --- Introduction / Chapter 1.1 --- Novel materials in the 21st century --- p.1 / Chapter 1.2 --- What are Nanocrystalline Materials? --- p.1 / Chapter 1.3 --- The superior properties of Nanocrystalline Materials --- p.2 / Chapter 1.4 --- Fabrication of Nanocrystalline Materials --- p.3 / Chapter 1.5 --- Flaws of the as-produced Nanophase Materials --- p.4 / Chapter 1.6 --- Theory of Phase Separation --- p.4 / Chapter 1.7 --- Nucleation and Growth --- p.6 / Chapter 1.7.1 --- Homogeneous nucleation / Chapter 1.7.2 --- Heterogeneous nucleation / Chapter 1.8 --- Spinodal Decomposition / Chapter 1.8.1 --- How SD differs from the classical diffusion process? / Chapter 1.8.2 --- Dynamics of SD / Chapter 1.8.3 --- How can we distinguish SD from Nucleation and Growth? / Chapter 1.8.4 --- Pore-free nanophase materials produced by Liquid Phase SD / Chapter 1.9 --- Thermal properties of the pore-free nanostructured Pd82Si18 Alloy --- p.12 / Chapter 1.9.1 --- A review of grain growth in nanophase materials / Chapter 1.9.2 --- Grain growth study on LSD Pd82Si18 alloy 一 aim and prospect / References --- p.18 / Figures --- p.21 / Chapter Chapter Two 一 --- Experimental / Chapter 2.1 --- Introduction --- p.28 / Chapter 2.2 --- From preparation of samples to microstructure analysis --- p.28 / Chapter 2.2.1 --- Alloying / Chapter 2.2.2 --- Fluxing / Chapter 2.2.3 --- Rapid Solification / Chapter 2.2.4 --- Annealing / Chapter 2.2.5 --- Microstructure analysis / Figures --- p.31 / Chapter Chapter Three ´ؤ --- Results and discussions / Thermal stability of bulk nanostructured alloys prepared by liquid phase spinodal decomposition --- p.34 / References --- p.40 / Table --- p.43 / Figures --- p.44 / Chapter Chapter Four ´ؤ --- Conclusions --- p.61

by Ng Kwok Leung = 納米鈀硅合金之機械特性 / 吳國良. / Thesis submitted in 2000. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / by Ng Kwok Leung = Na mi ba gui he jin zhi ji xie te xing / Wu Guoliang. / Acknowledgements --- p.ii / Abstract --- p.iii / 摘要 --- p.iv / Chapter Chapter 0 --- Prelude- A brief history of materials --- p.1 / Chapter Chapter 1 --- Introduction --- p.4 / Chapter 1.1 --- Introduction --- p.4 / Chapter 1.2 --- How are nanostructured materials produced? --- p.5 / Chapter 1.3 --- General properties of nanostructured materials --- p.7 / Chapter 1.4 --- Mechanical behaviour of nanostructured materials --- p.8 / Chapter 1.5 --- The solution --- p.12 / References --- p.20 / Figures --- p.22 / Chapter Chapter 2 --- Experimental --- p.30 / Chapter 2.1 --- Specimen preparation --- p.30 / Chapter 2.2 --- Means of analysis --- p.32 / Figures --- p.36 / Chapter Chapter 3 --- Synthesis of large nanostructured Pd82Si18 alloy --- p.39 / Abstract --- p.39 / References --- p.44 / Table and Figures --- p.45 / Chapter Chapter 4 --- Tensile behaviour of nanocrystalline Pd82Si18 alloy --- p.54 / Introduction --- p.54 / Experimental --- p.55 / Results --- p.57 / Discussions --- p.58 / References --- p.59 / Table and Figures --- p.60

Hong Liang = 用化学气相淀积方法生长氮化物纳米材料 / 洪亮. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / Hong Liang = Yong hua xue qi xiang dian ji fang fa sheng chang dan hua wu na mi cai liao / Hong Liang. / Acknowledgements --- p.ii / Abstract --- p.iii / Contents --- p.v / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Motivation --- p.2 / Chapter 1.2.1 --- A1N and AlGaN nanowires --- p.2 / Chapter 1.2.2 --- CVD --- p.3 / Chapter 1.3 --- Our work --- p.3 / Chapter Chapter 2 --- Experiment --- p.7 / Chapter 2.1 --- CVD system --- p.7 / Chapter 2.2 --- Sources and Substrates --- p.7 / Chapter 2.3 --- Growth of A1N nanowires --- p.8 / Chapter 2.4 --- Growth of AlGaN nanowires --- p.9 / Chapter Chapter 3 --- Characterization --- p.11 / Chapter 3.1 --- Scanning Electron Microscopy --- p.11 / Chapter 3.1.1 --- Topographic images by secondary electrons --- p.11 / Chapter 3.1.2 --- Elemental Analysis by Energy Dispersive X-ray --- p.12 / Chapter 3.2 --- Transmission Electron Microscopy --- p.12 / Chapter 3.3 --- X-Ray Diffraction --- p.14 / Chapter 3.4 --- Micro-Raman --- p.15 / Chapter Chapter 4 --- Results and Discussion --- p.18 / Chapter 4.1 --- A1N nano-structures --- p.18 / Chapter 4.1.1 --- A1N nano-leaves grown on silicon substrates --- p.18 / Chapter 4.1.2 --- A1N nanowires grown on silicon substrates --- p.19 / Chapter 4.1.3 --- SiNx nanowires grown on silicon substrates --- p.22 / Chapter 4.1.4 --- A1N nanowires grown on sapphire substrates --- p.26 / Chapter 4.1.5 --- Comparison with the results of other research groups --- p.31 / Chapter 4.2 --- AlGaN nano-structures --- p.33 / Chapter 4.2.1 --- AlGaN nanowires grown on silicon substrates --- p.33 / Chapter 4.2.2 --- Temperature dependence --- p.38 / Chapter 4.2.3 --- The influence of the mass ratio (Ga/Al) in the precursor metal sources --- p.43 / Chapter 4.2.4 --- Substrate effect --- p.46 / Chapter Chapter 5 --- Suggestion of the growth mechanism --- p.51 / Chapter 5.1 --- Growth mechanisms: an introduction --- p.51 / Chapter 5.2 --- The growth mechanisms for our produced samples --- p.57 / Chapter 5.2.1 --- Growth mechanism for A1N nanowires --- p.58 / Chapter 5.2.2 --- Growth mechanism for AlGaN nanowires --- p.61 / Chapter 5.2.3 --- Substrate effect --- p.65 / Chapter Chapter 6 --- Conclusions --- p.71 / Appendix --- p.73

自從 Onnes 于1911 年發現超導現象以來，超導就一直是凝聚態領域非常熱門的一個課題。隨之而來的一個問題是超導在量子尺寸效應的影響下將如何變化。在1959 年，Anderson 提出了一個超導受尺寸影響而消失的判據：當超導體的尺寸足够小以至於超導體費米面附近電子的平均能隙大於超導能隙或與其相當時，超導便被尺寸效應破壞。基於這個判據，超導和費米面附近的電子態密度密切相關。Si(111)表面上生長的鉛島在調製費米面附近的態密度上是一個很好的系統，因為它既可以在垂直方向上通過量子阱態調節，也可以通過水平方向的尺寸限制來調節。另外，相對於其他系綜或者粉末超導體，在Si(111)表面上生長的單個鉛島系統上研究超導排除了諸如尺寸分佈，顆粒間相互耦合以及相位漲落等因素對於超導的影響。 / 在這篇論文的緒論中，我首先簡單介紹了基本的超導知識，如 BCS 理論，Eliashberg 理論以及超導在超導體-絶緣體-正常金屬形成的隧道結上的表現形式。跟著，我重點回顧了之前在系綜超導體以及金屬納米結構中進行的超導尺寸效應研究。對於目前廣泛研究的鉛島系統，我將重點談及最近發現的贗能隙，這對研究鉛島的超導至關重要。 / 在第二章，我簡單介紹了樣品的生長和掃描隧道譜的相關知識。爲了分析鉛島的超導譜，我們用了兩種方法去分析他們。一種是零電壓下電導的方法，另一種是超導譜分析方法。在這章的最後，我詳細介紹了Dynes 方程及去捲積的方法。 / 在第三章，我將介紹我博士學習期間一個非常重要的工作，提高儀器的能量分辨率。通過改造儀器結構，合理的接地，屏蔽射頻噪聲，以及清除電壓源的噪聲，我成功地將能量分辨率從0.9 meV 提高到0.2 meV。在最後我會將儀器改進后的結果與之前的結果儀器與其他組的結果進行比較。 / 在儀器改進之前，我們發現那時的測量結果非常差，由此得出的結論也是不正確的。爲了比較儀器改造的重要性，在第四章，我將簡單介紹儀器改進前的結果。在當時差的條件下，我們探測出對於9ML 厚的鉛島，3.2 K 以上不超導的鉛島尺寸，大約為30 nm²。並且鉛島經歷了一個從強電子聲子耦合到弱電子聲子耦合的轉變。 / 在儀器改進之後，我們不僅糾正了之前在九層鉛島上進行超導研究時的一些結論。此外，也觀察到了由於尺寸變化或者費米面上態密度變化導致超導的細微區別。由於尺寸效應，我們發現在一些小的鉛島上存在一個過渡區。另外，由於八層鉛島費米面上的態密度比九層的高，超導轉變溫度也因此有一個系統性的提高。對於這兩個層數的鉛島，他們的超導轉變溫度都隨尺寸減小受到一個緩慢的抑制。對於非常小的鉛島，我們發現其仍然超導。這和Anderson 判據的預期以及其他實驗結果不一致，激發我們進一步探索是否非晶化的潤濕層參與了這種非常小的鉛島的超導。 / 這些工作，對於全面理解超導的尺寸效應以及態密度影響是非常基本和關鍵的，這也將進一步激發人們在這個領域進行更多的探索。 / Superconductivity has always been a hot topic in the field of condensed matter physics since its discovery by Onnes in 1911. How the superconductivity was affected by size attracted much attention especially after P. W. Anderson proposed a criterion of the breakdown of superconductivity in 1959, where the superconductors will lose their superconductivity when the energy level spacing at Fermi level (E[subscript F]) is comparable to or larger than the superconducting energy gap. As stated in the criterion, the superconductivity correlates greatly with the density of states (DOS) at E[subscript F] within the superconducting gap. The system of individual Pb islands grown on Si(111) provides an ideal platform to modulate the DOS at EF through both the quantum size confinement and the quantum well states (QWS) effects. Moreover, this system excludes the problems of size distribution, couplings among particles and phase fluctuation of the previously studied ensembles of particles. / In my thesis, I first introduce briefly the basic knowledge of superconductivity, such as BCS theory and Eliashberg theory, as well as its behaviors in a normal metal-insulator-superconductor tunneling junction. Then the study of superconductivity by quantum size effect on ensemble superconductors and metallic nanostructures is reviewed. For the widely studied system of Pb islands, I discuss in more detail the recently discovered pseudogap which was important and critical for analyzing the superconductivity. / In chapter 2, the knowledge of sample growth is given and a simple introduction to scanning tunneling spectroscopy is presented. To study the superconductivity spectra of Pb islands, we use two methods to analyze them, one the zero bias conductance (ZBC) method and the other the superconductivity spectrum analysis. In the end of this chapter, Dynes function and deconvolution procedure are introduced in detail. / In chapter 3, I introduce one of my important works in my Phd study, to improve the instrumental energy resolution. By reconstructing the instrumental structure, grounding properly, shielding RF noise, and cleaning the voltage gap source, the instrumental energy resolution has been improved greatly from ~0.9 meV to ~0.2 meV. I compare our current results both with previous results and results from other groups. / Before the instrumental improvement, we find that the measurements were very poor and the conclusion thus obtained were incorrect. To show the importance of the instrumental improvement, I introduce briefly the previous work in chapter 4. Under the poor instrumental condition, we found that the limiting size of superconductivity above 3.2 K was determined to be ~30 nm² for 9 ML thick Pb islands and that Pb island superconductors undergo a change from strong to weak electron-phonon coupling. / After the instrumental improvement, we not only correct some conclusions of the previous studies on superconductivity of 9 ML Pb islands, but also observed the more non-trivial variation of superconductivity from the change of island size or density of state (DOS) at Fermi level (E[subscript F]) by the quantum well states (QWS). A critical regime is observed for small Pb islands. As the DOS of 8 ML Pb islands at E[subscript F] is larger than that of 9 ML Pb islands, the transition temperatures (T[subscript C]) of 8 ML Pb islands hold a systematic difference larger than those of 9 ML Pb islands. The T[subscript C] results for both 8 ML and 9 ML Pb islands follow the same gradual suppression and the ratio 2△(0)/k[subscript B]T[subscript C] remains unchanged by the size effect. Further study indicates that for very small 8 ML and 9 ML Pb islands they are still superconducting, inconsistent with the Anderson criteria and other experimental results. This observation suggests a possible role of wetting layer on superconductivity of these small Pb islands. / This work, I believe, is fundamentally interesting and beneficial to understand deeply the phenomena of superconductivity modulated by size effect and DOS change at E[subscript F] and will inspire more future studies in this field. / 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. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Liu, Jiepeng = 掃描隧道譜研究Si(111)表面上單個鉛島的超導尺寸效應及態密度影響 / 羅杰鵬. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 136-144). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Liu, Jiepeng = Sao miao sui dao pu yan jiu Si(111) biao mian shang dan ge qian dao de chao dao chi cun xiao ying ji tai mi du ying xiang / Luo Jiepeng. / Chapter 1 --- Superconductivity affected by quantum size effect --- p.2 / Chapter 1.1 --- Overview --- p.3 / Chapter 1.2 --- Basic theories to superconductivity --- p.4 / Chapter 1.2.1 --- BeS theory --- p.5 / Chapter 1.2.2 --- Eliashberg equation --- p.8 / Chapter 1.2.3 --- Superconductivity of S-I-N tunneling junction --- p.10 / Chapter 1.3 --- Size effect of superconductivity for ensemble or powder superconductors --- p.12 / Chapter 1.3.1 --- Anderson criteria --- p.13 / Chapter 1.3.2 --- Size-dependent T[subscript C] for different superconductors --- p.13 / Chapter 1.4 --- Size effect of superconductivity for metallic nanostructures --- p.17 / Chapter 1.4.1 --- Metallic nanostructures --- p.17 / Chapter 1.4.2 --- Quantum well states of metallic nanostructures --- p.18 / Chapter 1.4.3 --- Pb nanostructures on Si(111)-7 x 7 --- p.20 / Chapter 1.5 --- summary --- p.25 / Chapter 2 --- Experimental introductions and data analysis methods --- p.26 / Chapter 2.1 --- Experimental introduction --- p.27 / Chapter 2.1.1 --- Growth of Pb islands --- p.28 / Chapter 2.1.2 --- Substrates effects --- p.32 / Chapter 2.2 --- STS studies of Pb islands --- p.36 / Chapter 2.2.1 --- Basic knowledge of STS --- p.36 / Chapter 2.2.2 --- STS results of Pb islands --- p.40 / Chapter 2.3 --- Data analysis methods --- p.41 / Chapter 2.3.1 --- Zero bias conductance analysis --- p.41 / Chapter 2.3.2 --- Superconductivity spectrum analysis --- p.43 / Chapter 2.4 --- Dynes function fitting --- p.44 / Chapter 2.4.1 --- Dynes function --- p.44 / Chapter 2.4.2 --- Deconvolution --- p.47 / Chapter 2.4.3 --- BCS-like analysis --- p.49 / Chapter 2.5 --- Summary --- p.50 / Chapter 3 --- Instrument improvements --- p.51 / Chapter 3.1 --- Previously existed problems --- p.52 / Chapter 3.2 --- Problem analysis and solutions --- p.54 / Chapter 3.2.1 --- Structure and Preamplifier --- p.54 / Chapter 3.2.2 --- Grounding --- p.56 / Chapter 3.2.3 --- Bias voltage source cleaning --- p.57 / Chapter 3.2.4 --- RF noise shielding --- p.60 / Chapter 3.3 --- Tip drift in perpendicular direction when taking STS --- p.65 / Chapter 3.4 --- Improved results --- p.68 / Chapter 3.4.1 --- Comparisons with previous results --- p.68 / Chapter 3.4.2 --- Comparisons with other groups --- p.69 / Chapter 3.5 --- Summary --- p.72 / Chapter 4 --- Superconductivity of 9 ML thick Pb islands with poor energy resolution --- p.75 / Chapter 4.1 --- STS results --- p.76 / Chapter 4.1.1 --- STS results at large energy scale --- p.76 / Chapter 4.1.2 --- STS results at small energy scale Zero bias conductance analysis --- p.79 / Chapter 4.2.1 --- ZBC results --- p.79 / Chapter 4.2.2 --- Comparisons with theoretical calculations --- p.83 / Chapter 4.3 --- Superconductivity spectrum analysis --- p.85 / Chapter 4.3.1 --- Method to obtain superconductivity spectra --- p.86 / Chapter 4.3.2 --- BCS-like analysis --- p.93 / Chapter 4.4 --- Explanation and possible mechanism --- p.97 / Chapter 4.5 --- Summary --- p.99 / Chapter 5 --- DOS modulated superconductivity with improved energy resolution --- p.101 / Chapter 5.1 --- Introduction --- p.102 / Chapter 5.2 --- Experiments --- p.103 / Chapter 5.3 --- Behaviors of zero bias conductance results --- p.104 / Chapter 5.3.1 --- Power law behavior --- p.104 / Chapter 5.3.2 --- Critical regime and To determination --- p.106 / Chapter 5.4 --- Recheck previous results --- p.112 / Chapter 5.4.1 --- Pseudogap --- p.112 / Chapter 5.4.2 --- Transition temperature --- p.115 / Chapter 5.5 --- DOS modulated superconductivity --- p.121 / Chapter 5.5.1 --- Quantum well states of 8 ML and 9 ML Pb islands --- p.121 / Chapter 5.5.2 --- T[subscript C] behavior on a 8 ML and 9 ML Pb island --- p.123 / Chapter 5.5.3 --- Superconductivity behaviors for a set of 8 ML and 9 ML Pb islands --- p.124 / Chapter 5.5.4 --- Superconductivity of very small Pb islands --- p.129 / Chapter 5.6 --- Summary --- p.130 / Chapter 6 --- Conclusions and outlook --- p.132 / Chapter 6.1 --- Conclusions --- p.133 / Chapter 6.2 --- Outlook --- p.134 / Bibliography --- p.136

Nanophotonics is a fast-growing area of both scientific significance and practical value for applications. Nanophotonics studies the interaction between light and electronic systems in nanomaterials and nanostructures as well as the behavior of light in nanometer scales. It covers many hot topics such as plasmonics, two-dimensional materials, and silicon photonics. Increasing attention is given to the area and nanophotonics is expected to have significant impact on future technology advances. This thesis work focuses on three aspects of nanophotonics. The first aspect is in exploring the nonlocal effect and surface correction for nanometer-length-scale plasmonic structures. Plasmonics is the study of the interaction between electromagnetic fields and free electrons in a metal. It exploits the unique optical properties of metallic nanostructures to enable routing and manipulation of light at the nanoscale, where nonlocal effect becomes important. Here we introduce a new surface hydrodynamic model for plasmon propagation at interfaces, which incorporates both nonlocality and surface contributions. This surface correction is calculated via a discontinuity in the normal component of the electric displacement in conjunction with Feibelman's d-parameters, thus enabling rapid numerical calculation of nanostructures without requiring a full quantum calculation because of its large computational requirement. We examine numerical calculations of surface plasmon polaritons propagation at a single interface structure, and then for a more complex thin-film structures. The second aspect is investigating the third-harmonic generation in thick multilayer graphene. Graphene is the first two-dimensional material to be discovered and has attracted much interest because of its remarkable two-dimensional electronic, optical, mechanical, and thermal properties. Multilayer graphene, can be seen as stacking of monolayer graphene, and it offers an array of properties that are of interest for optical physics and devices. We describe the layer-dependent for third-harmonic generation in thick multilayer graphene on quartz substrate. The third harmonic signal of multilayer graphene exhibits a complex dependence on its layer number showing that the optimal third harmonic signal at 24 layers, in good agreement with two theoretical models. The third aspect is an exploration in silicon photonics of design and demonstration of a differential phase shift keying demodulator based on coherent perfect absorption effect. Silicon photonics is considered a potential future communication system mainly due to its compact footprint, dense integration, and compatibility with mature silicon integrated circuit manufacturing. Differential phase shift keying based system offers advantages, e.g., dispersion tolerance, improved sensitivity, and does not require coherent detection. Coherent perfect absorption uses a ring resonator works for the critical coupling condition at resonance frequency. This work shows a new compact demodulator circuit can be integrated in all optical-system.

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by Leung Kit Sum = 透過X光電子譜研究射頻濺射之銅復合物石英 / 梁潔心. / Thesis submitted in: August 2002. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 77-78). / Text in English; abstracts in English and Chinese. / by Leung Kit Sum = Tou guo X guang dian zi pu yan jiu she pin jian she zhi tong fu he wu shi ying / Liang Jiexin. / Abstract --- p.i / 論文摘要 --- p.iii / Acknowledgement --- p.iv / Table of Content --- p.v / List of Figures --- p.ix / List of Tables --- p.xi / Chapter CHAPTER 1 --- INTRODUCTION / Chapter 1.1 --- Nanoparticles and Nanophase Materials --- p.1 / Chapter 1.2 --- Nonlinear Optical Phenomena and Their Physical Origin --- p.4 / Chapter 1.2.1 --- Dielectric Confinement --- p.6 / Chapter 1.2.2 --- Quantum Confinement --- p.8 / Chapter 1.2.2.1 --- Intraband Transition --- p.9 / Chapter 1.2.2.2 --- Interband Transition --- p.9 / Chapter 1.2.2.3 --- Hot-electron Transition --- p.11 / Chapter 1.3 --- Importance of Optical Nonlinearity --- p.11 / Chapter 1.3.1 --- Self-Phase Modulation --- p.11 / Chapter 1.3.2 --- Self-Focusing/Defocusing --- p.12 / Chapter 1.4 --- Sample Preparation --- p.12 / Chapter 1.4.1 --- Sputtering --- p.13 / Chapter 1.5 --- Characterization of Nanocomposites --- p.15 / Chapter 1.6 --- Aim of the Project --- p.15 / References --- p.17 / Chapter CHAPTER 2 --- INSTRUMENTATION / Chapter 2.1 --- Introduction --- p.20 / Chapter 2.2 --- Sputter Deposition --- p.20 / Chapter 2.2.1 --- Glow Discharge --- p.21 / Chapter 2.2.2 --- Radio-Frequency Sputtering (RF Sputtering) --- p.24 / Chapter 2.2.3 --- Magnetically Enhanced Sputtering --- p.24 / Chapter 2.2.4 --- Instrumentation --- p.25 / Chapter 2.2.4.1 --- Target Assemblies --- p.27 / Chapter 2.2.4.2 --- Shutter --- p.28 / Chapter 2.2.4.3 --- Substrate Holder --- p.28 / Chapter 2.2.4.4 --- Power Supply --- p.28 / Chapter 2.2.5 --- Experimental --- p.29 / Chapter 2.3 --- X-ray Photoelectron Spectroscopy (XPS) --- p.29 / Chapter 2.3.1 --- Instrumentation --- p.31 / Chapter 2.3.2 --- Application to metal nanoclusters composite glass --- p.33 / Chapter 2.3.2.1 --- Compositional Analysis --- p.33 / Chapter 2.3.2.2 --- Depth Profiling --- p.33 / Chapter 2.3.3.3 --- Auger Parameters --- p.33 / Chapter 2.4 --- Transmission Electron Microscopy (TEM) --- p.34 / Chapter 2.4.1 --- Sample Preparation --- p.35 / Chapter 2.4.1.1 --- Sample Thickness Determination --- p.35 / Chapter 2.4.1.2 --- Ion Milling --- p.36 / Chapter 2.4.2 --- Instrumentation --- p.36 / Chapter 2.4.3 --- Contrast and Image Formation --- p.38 / Chapter 2.4.3.1 --- Bright and Dark Field Image --- p.38 / Chapter 2.4.3.2 --- Mass and Thickness Contrast --- p.40 / Chapter 2.4.3.3 --- Diffraction Contrast --- p.40 / References --- p.42 / Chapter CHAPTER 3 --- COMPOSITION AND NANUSTRUCTURE OF COPPER DOPED FUSED SILICA / Chapter 3.1 --- Introduction --- p.44 / Chapter 3.2 --- Experiment --- p.45 / Chapter 3.3 --- Results and Discussion --- p.47 / Chapter 3.3.1 --- Effect of Input RF Power on the Growth of Film --- p.47 / Chapter 3.3.2 --- Theoretical Calculation of Cluster Size by Ratio of Surface to Total Amount of Copper --- p.55 / Chapter 3.3.3 --- TEM Studies of Copper Nanoclusters --- p.57 / Chapter 3.3.4 --- Further Discussion: Effect of Current and Voltage on the Determination of Deposition Rate --- p.60 / Chapter 3.3.5 --- Atomic Distribution and Chemical State of Copper Nanocluster --- p.60 / Chapter 3.3.6 --- Effect of Pressure on the Growth of Film --- p.66 / Chapter 3.3.6.1 --- How Pressure Affects Cluster Growth --- p.70 / Chapter 3.3.7 --- Effect of Deposition time on the Growth of Film --- p.71 / Chapter 3.3.7.1 --- How Film thickness Affects Cluster Growth --- p.75 / Chapter 3.4 --- Summary --- p.75 / References --- p.77 / Chapter Chapter 4 --- CONCLUSION AND FUTURE DIRECTIONS / Chapter 4.1 --- Conclusion --- p.79 / Chapter 4.2 --- Future Directions --- p.79 / Chapter 4.2.1 --- Generation of Active Matrix Nanocomposite --- p.79

At last, a thermal evaporation method that modifies the surface of ZnO nanorods and forms core shell structure is developed, which structure constitutes the photoelectrode for solar energy application. Single crystal ZnO nanorods are uniformly covered by wurtzite polycrystalline CdxZn1-x SySe1-y layer. The band gap of the shell can be systematically tuned from 2.5 to 1.7 eV by varying its composition, as suggested by the optical extinction measured of the samples. The type II band alignment between the ZnO core and the alloy shell enables effective photo-generated charge carrier separation, and the single crystalline ZnO nanorod array provides a direct electrical pathway for the photo-injected electron transport. The nanocable solar cells exhibited short-circuit current ∼0.2 mA/cm 2 and open-circuit voltages of 0.45 V when illuminated with 100 mW/cm 2 simulated AM 1.5 spectrum. / Green emission is observed from the ZnO nanorods synthesized by both methods, which is commonly attributed to the surface defect emission from the nanostructure. We modify surface of the nanorods with SiO 2 and investigate the relation between green emission and the surface defect. However, the surface passivation fails to reduce the green emission significantly, suggesting that surface defects of ZnO are not necessarily responsible for the green emission, but the interior structure quality of the ZnO nanorods decides the luminescence behavior. / In this study, a solution chemistry based method to grow aligned ZnO nanorod arrays on Zn foil is developed at first. Effects of various growth parameters, including the temperature, solution composition and the concentration of individual components on the morphology, structural quality, and properties of the ZnO nanorods are studied. The average diameter of the nanorods in the array can be tuned from ∼20 nm to ∼150 nm by systematically changing the growth conditions. Nanorods with larger diameters are found to be of better structural quality as compared to the smaller diametered ones, as suggested by the cathodoluminescence measurement. Following similar logic, a vapor transport deposition route on controllable fabricating of the ZnO nanorod arrays is investigated. The average diameter of the ZnO nanorods can be tuned from less than 40 nm to larger than submicron, by controlling the fabrication conditions. Larger-diametered nanorods that grow on higher temperature zone are found to possess higher band edge to defect emission ratio. / One dimensional (1D) ZnO nanostructure becomes a research focus in recent years. On the one hand, ZnO itself possesses structural, electrical and optical properties that make it useful for a diverse range of technological applications. On the other hand, semiconductor nanowire owns many advantages, such as superiority in electron transport and its high surface to volume ratio. Aligned ZnO 1D nanostructures on conducting substrates are of special interests, as they are easy to be integrated into devices, directly working as functional unit. / Jiao, Yang. / Adviser: Li Quan. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 107-109). / 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. / Abstract also in Chinese. / Jiao, Yang.