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Ip Kit Man = 準一維的硒化鋅納米結構的光致發光研究 / 葉潔雯. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 68-71). / Text in English; abstracts in English and Chinese. / Ip Kit Man = Zhun yi wei de xi hua xin na mi jie gou de guang zhi fa guang yan jiu / Ye Jiewen. / ACKNOWLEDGEMENTS --- p.i / ABSTRACT --- p.ii / TABLE OF CONTENTS --- p.vi / LIST OF TABLE --- p.vii / LIST OF FIGURES --- p.viii / Chapter Chapter1 --- Introduction / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Literature review --- p.2 / Chapter 1.3 --- Our study --- p.4 / Chapter 1.4 --- Growth conditions --- p.4 / Chapter Chapter2 --- Background / Chapter 2.1 --- Basic principle of PL --- p.6 / Chapter 2.2 --- Theories of excitations in semiconductor / Chapter 2.2.1 --- Bandgap and temperature effect of ZnSe --- p.8 / Chapter 2.2.2 --- Structure of ZnSe --- p.13 / Chapter 2.3 --- Surface effects --- p.16 / Chapter 2.4 --- Gas -Surface Interaction --- p.20 / Chapter Chapter 3 --- Experimental Procedures / Chapter 3.1 --- Setup of PL Spectroscopy --- p.21 / Chapter 3.2 --- Passivation and separation of ZnSe nanostructures --- p.26 / Chapter Chapter 4 --- Results and Discussions / Chapter 4.1 --- Analysis of ZnSe/Si nanostructures / Chapter 4.1.1 --- "Morphology, structure and separation of as-grown ZnSe/Si nanostructures" --- p.30 / Chapter 4.1.2 --- Temperature dependent PL of as-grown and very low density ZnSe/Si nanostructures --- p.33 / Chapter 4.1.3 --- Temperature dependent PL of ZnSe/Al203 nanowires --- p.41 / Chapter 4.1.4 --- Growth conditions dependence on PL --- p.44 / Chapter 4.1.4a --- PL result comparison: ZnSe grown on 3 different substrate --- p.45 / Chapter 4.1.4b --- PL result comparison: Silver and gold catalyst --- p.45 / Chapter 4.2 --- Analysis of the ammonium sulfide treated samples / Chapter 4.2.1 --- XPS results of ammonium sulfide treated samples --- p.47 / Chapter 4.2.2 --- Relationship between immersion time and enhancement factors of PL intensity --- p.49 / Chapter 4.3 --- Analysis of effects in PL of ZnSe/Si nanostructures in different gas ambients --- p.53 / Chapter Chapter 5 --- Conclusions --- p.66 / References --- p.68

Liu Zhuang = 硒化鋅准一維納米結構的形貌和陰極射線致發光的研究 / 劉壯. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 60-63). / Text in English; abstracts in English and Chinese. / Liu Zhuang = Xi hua xin zhun yi wei na mi jie gou de xing mao he yin ji she xian zhi fa guang de yan jiu / Liu Zhuang. / ABSTRACT --- p.i / ACKNOWLEDGMENTS --- p.iii / TABLE OF CONTENTS --- p.iv / LIST OF TABLES --- p.vi / LIST OF FIGURES --- p.vii / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Synthesizing quasi one-dimensional nanostructures of ZnSe using MOCVD --- p.1 / Chapter 1.2 --- Well-aligned nanostructures and heterocrystalline nanorods --- p.2 / Chapter 1.3 --- Advantages of CL in studying nanostructures --- p.3 / Chapter 2. --- Experimental conditions and procedures --- p.7 / Chapter 2.1 --- Information on the samples --- p.7 / Chapter 2.2 --- SEM and CL setting --- p.9 / Chapter 2.3 --- CL calibration --- p.10 / Chapter 3. --- Experimental results and data analysis --- p.14 / Chapter 3.1 --- SEM results and discussion --- p.14 / Chapter 3.1.1 --- SEM studies helping to find the optimal growth condition --- p.14 / Chapter 3.1.2 --- Morphological studies --- p.18 / Chapter 3.1.3 --- The growth direction of well-aligned nanostructure --- p.22 / Chapter 3.1.4 --- Discussion of the growth mechanisms of the nanostructures based on the morphological studies --- p.28 / Chapter 3.2 --- CL results and discussion --- p.34 / Chapter 3.2.1 --- CL spectra of nanostructures of different morphologies --- p.34 / Chapter 3.2.2 --- CL images for studying of distribution of localized radiative centers --- p.40 / Chapter 3.2.3 --- CL studies of a single nanorod --- p.44 / Chapter 3.2.3.1 --- Room temperature CL studies of a single nanorod --- p.44 / Chapter 3.2.3.2 --- Liquid Helium temperature (4.5 K) CL studies of a single nanorod --- p.50 / Chapter 4. --- Conclusions --- p.59 / Reference --- p.60

The synthesis of n-alkylamine-bound CdSe-NH2Rʹ nanocrystals from carboxylateterminated CdSe-Cd(O2CR)2/HO2CR requires the removal of acidic impurities prior to the addition of primary amine. Otherwise, the formation and subsequent tight binding of n-alkylammonium carboxylate ion pairs prevents quantitative removal of carboxylate species. Dimethylcadmium and diethylzinc were used as reagents to deprotonate acidic impurities, which either causes methylation (with a surface density of 0.04−0.22 nm−2) and photoinduced reduction of the nanocrystal core or X-type ligand exchange with ethyl species, respectively. The acid-scavenged nanocrystals could be completely isolated from displaced carboxylate ligands (≤ 0.01 carboxylates nm-2). In addition to traditional selective precipitation procedures, gel permeation and silica chromatography were investigated as alternative purification methods for the isolation of CdSe-NH2Rʹ. Both demonstrated no improvement compared to the more convenient precipitation process. Thin films fabricated from CdSe-NH2C4H9 show little to no grain growth upon thermal annealing at 250 ºC, maintaining domains (~10 nm) despite complete desorption of n-butylamine from the nanocrystal surface above 150 ºC. Despite no passivation of the surface and a high density of grain boundaries, thin film transistors of CdSe-NH2C4H9 fabricated on thermally grown silicon dioxide gate dielectrics produce field-effect transistors with an average electron mobility of 12 ± 1 cm2 V-1s-1, a low threshold voltage hysteresis (4.0 ± 0.6 Vth), and an on/off ratio of 8x104. Colloidal dispersions of amine bound nanocrystals (CdSe−NH2Rʹ) are indefinitely stable at amine concentrations of 0.1 M or higher and slowly aggregate at lower concentrations. Dissociation and evaporation of the amine ligands in 4-ethylpyridine, tri-n-butylphosphine, or molten tri-n-octylphosphine oxide solution results in nanocrystal aggregation. Greater stability can be achieved using dimethyl-n-octadecylphosphine as the L-type ligand, yielding soluble CdSe- PMe2C18H37 nanocrystals with a phosphine coverage of 1.8 nm-2. CdSe-PMe2C18H37 is the first stable nanocrystal sample bound solely by neutral phosphines. Z-type rebinding was investigated with metal oleate species (Mn+(O2CR)n, M = Cd2+, Zn2+, Pb2+, In3+), and a relative binding affinity of these complexes can be established. Rebinding of metal oleate species at 25 ºC yield lower coverages, yet can reach saturation upon heating to 100 ºC. The rebinding of cadmium chloride to aggregated CdSe-PBu3 stabilizes the particle and aids in their redissolution. L-type ligand exchange and subsequent Z-type rebinding was employed towards the synthesis of a new model compound passivated by dimethyl-n-octadecylphosphine and cadmium trifluoroacetate ligands, CdSe-Cd(O2CCF3)2/PMe2C18H37, which is characterized by UV-Vis, 1H, 19F, and 31P NMR spectroscopies. The findings of this dissertation demonstrate the importance of ion-pair species in the colloidal stabilization of colloidal nanocrystal systems. It also indicates the utility of stoichiometric, amine and phosphine-bound CdSe-L to act as both reporter complexes and as a clean reactive reagent for synthesis of novel CdSe-MX2/L systems to study the molecular interactions at nanocrystal surfaces.

Lam, Ngai Sze. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / Lam, Ngai Sze. / Abstract --- p.i / Acknowledgements --- p.iii / Table of contents --- p.iv / List of Figures --- p.viii / List of Tables --- p.xiii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.1.1 --- Properties of CdSe --- p.1 / Chapter 1.1.2 --- Synthesis of CdSe one-dimensional (ID) nanostructure --- p.5 / Chapter 1.1.3 --- Application of CdSe nanostructures --- p.8 / Chapter 1.1.4 --- Significance of surface engineering --- p.10 / Chapter 1.1.4.1 --- Surface passivation --- p.11 / Chapter 1.1.4.2 --- Surface functionalization --- p.11 / Chapter 1.1.4.3 --- Modulation of optical/electrical properties --- p.12 / Chapter 1.2 --- Present study --- p.14 / Chapter 1.2.1 --- Objective --- p.14 / Chapter 1.2.2 --- General methodology --- p.14 / Chapter Chapter 2 --- Instrumentation --- p.19 / Chapter 2.1 --- Introduction --- p.19 / Chapter 2.2 --- Setup of Sample Preparation --- p.19 / Chapter 2.2.1 --- Synthesis --- p.19 / Chapter 2.2.1.1 --- Thermal evaporation apparatus --- p.19 / Chapter 2.2.1.2 --- Microwave assisted chemical synthesis --- p.21 / Chapter 2.2.2 --- Sample handling --- p.22 / Chapter 2.2.3 --- Other treatments --- p.22 / Chapter 2.3 --- X-ray photoelectron spectrometer (XPS) --- p.22 / Chapter 2.3.1 --- Basic Principle --- p.22 / Chapter 2.3.2 --- Instrumentation --- p.24 / Chapter 2.3.3 --- Charging problem --- p.27 / Chapter 2.3.4 --- Qualitative analysis --- p.27 / Chapter 2.3.5 --- Quantitative analysis --- p.28 / Chapter 2.3.5.1 --- Curve fitting --- p.28 / Chapter 2.3.5.2 --- Atomic percentage --- p.29 / Chapter 2.3.5.3 --- Thickness determination --- p.29 / Chapter 2.4 --- Photoluminescence --- p.30 / Chapter 2.4.1 --- Basic principle --- p.30 / Chapter 2.4.2 --- Instrumentation --- p.31 / Chapter 2.5 --- Other equipments --- p.32 / Chapter Chapter 3 --- Synthesis of CdSe Nanorods --- p.34 / Chapter 3.1 --- Introduction --- p.34 / Chapter 3.2 --- Thermal evaporation --- p.34 / Chapter 3.2.1 --- Experimental procedures --- p.34 / Chapter 3.2.2 --- Characterization --- p.35 / Chapter 3.3 --- Microwave assisted method --- p.41 / Chapter 3.3.1 --- Experimental procedures --- p.41 / Chapter 3.3.2 --- Characterization --- p.42 / Chapter 3.4 --- Summary --- p.47 / Chapter Chapter 4 --- Surface Treatment of CdSe Nanorods --- p.49 / Chapter 4.1 --- Introduction --- p.49 / Chapter 4.2 --- Experimental procedures --- p.50 / Chapter 4.3 --- Results and Discussion --- p.51 / Chapter 4.3.1 --- Formation of Se-coated CdSe NRs --- p.51 / Chapter 4.3.2 --- Desorption and thinning --- p.56 / Chapter 4.3.3 --- Surface degradation --- p.67 / Chapter 4.4 --- Summary --- p.69 / Chapter Chapter 5 --- Surface Capping of CdSe Nanorods --- p.73 / Chapter 5.1 --- Introduction --- p.73 / Chapter 5.2 --- Experimental procedures --- p.73 / Chapter 5.3 --- Results and Discussion --- p.74 / Chapter 5.3.1 --- Capping of thiol with halo-functional group --- p.74 / Chapter 5.3.1.1 --- Compositional analysis --- p.75 / Chapter 5.3.1.2 --- PL analysis --- p.79 / Chapter 5.3.2 --- Capping of DNA --- p.81 / Chapter 5.3.2.1 --- Compositional analysis --- p.81 / Chapter 5.3.2.2 --- PL analysis --- p.83 / Chapter 5.4 --- Summary --- p.92 / Chapter Chapter 6 --- Conclusions and Future Work --- p.94 / Chapter 6.1 --- Conclusions --- p.94 / Chapter 6.2 --- Future work --- p.95

Graduation date: 1994

Thesis (Ph. D.)--University of Oregon, 2002. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 143-148). Also available for download via the World Wide Web; free to University of Oregon users.

Stuttgart, Univ., Diss., 1999.

A sensitive nuclear magnetic resonance spectrometer has been constructed using Field Effect Transistors in a Robinson configuration. The spectrometer has been used to study the anomalous nuclear magnetic resonance spectra of single crystals of NbSe₂. An analysis of the field dependence of the line width in the low temperature phase has demonstrated that this results from a distribution of Knight Shifts. Such a distribution is not consistent with a structural transformation involving only two nonequivalent sites as proposed by Ehrenfreund et al. In addition accurate measurements of the Knight Shift and electric field gradient tensor have been made in the high temperature phase at 77K and 300K. The Knight Shift has a very large anisotropic component but an almost zero isotropic component which is indicative of negligible s-electron character at the: Fermi surface. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

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