D.Ing. (Electrical And Electronic Engineering ) / Please refer to full text to view abstract

M.Sc. / Please refer to full text to view abstract

An automated ellipsometer was used to study field-induced optical anisotropy in anodic niobium oxide films. The oxide films were found to change from the optically isotropic state to the optically anisotropic state when an electric field was applied normal to the film surface. The anisotropic refractive indices of the oxide films decreased quadratically while the thickness of the films increased quadratically with the applied field. The quadratic electro-optic coefficients were determined. The changes in refractive indices and in thickness of the oxide films were found to be independent of time. Field recrystallization of the anodic niobium oxide films was investigated using a scanning electron microscope. The results are compared with those reported for anodic tantalum oxide films in the published literature. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

The optical propagation losses resulting from the internal microstructure of ZnS thin films were investigated using a wavelength technique. Waveguide losses were determined by measuring the scattered light as a function of propagation distance along the film. Accurate measurements were obtained by using a technique we developed that employees a coherent fiber bundle to transfer the scattered light streak to a remote image plane that was scanned with an apertured photomultiplier tube. Microstructure effects on losses were found to dominate effects caused by substrate surface finish. The magnitude of the loss was found to depend upon two independent parameters: the average grain size of the polycrystalline films and the refractive index difference between ZnS and the interstitial material. Increasing the H₂O partial pressure led to lower losses as a result of reduced crystallite size, and a change in preferential crystallite orientation. A similar change in orientation was observed for films deposited onto heated substrates. Increasing the O₂ partial pressure during deposition also resulted in slightly lower waveguide losses, possibly as a result of void filling with ZnO. The modal dependence of the losses for ZnS films deposited at ambient temperature suggests that volume losses dominate surface losses for the lowest order mode while the ratio of surface to volume losses increases for higher order modes. By depositing ZnS onto substrates cooled with liquid nitrogen, adatom surface mobility was reduced which resulted in amorphous films. Losses were minimized (≤0.5 dB/cm at λ = 633 nm) for a substrate temperature of -50°C. These losses are lower than any previously reported for ZnS. However, further reduction of the substrate temperature resulted in an increase in tensile stress which eventually led to higher waveguide losses and crazing. The films deposited onto cooled substrates exhibited a low refractive index which indicates a low packing density and increased porosity. Differential water desorption, which is further evidence of increased porosity, was most noticeable in films with lower refractive indices when nonlinear prism coupling was attempted.

M.Ing. / This work comprises the implementation and comparison of five design techniques for the design of gradient-index thin film optical filters: classical rugate, inverse Fourier transform, a wavelet-based design procedure, as well as the flip-flop and the genetic optimization techniques. Designs for a high-reflectance filter, a beamsplitter, a discrete level filter, a distributed filter, and an anti-reflection coating were used to compare the various filter synthesis techniques. The optical thickness of the various examples was maintained below 30 and the refractive index excursion limits were between 1.5 and 3.2. The overall performance of a specific design was evaluated by a weighted merit function. The classical rugate filter uses a sinusoidal refractive index modulation that produces a single reflection band. More complex filters are realized by linear superposition of these elementary profiles. Sidelobe and ripple suppression are obtained by applying quintic windowing functions to the refractive index profile and adding matching layers at the edges of the filter. This filter design procedure has the best figure of merit of 3.73 for the discrete level filter, and the second best of 3.09 for the high-reflectance filter. The inverse Fourier transform links the refractive index profile and reflection spectrum of an optical filter by an approximate relation. It is self-correcting and iterative in nature. It produces filters with the highest optical density. The procedure excels in the design of the distributed filter with a figure of merit of 4.17. Mortlett's wavelet is used as the basis of the wavelet design technique. A single wavelet yields a single reflection band, similar to the classical rugate filter. Sidelobe suppression is an inherent property of the method, but matching layers are needed for passband ripple suppression. The optical density of the high reflection filter is larger for a filter designed with this method than for the equivalent classical rugate filter. The figure of merit of 1.75 for the high-reflectance filter is the best for any of the designs. Flip-flop refinement is a brute force approach to filter design. The layers of a starting design are flipped between two values of refractive index, the change in figure of merit evaluated and the best case saved. This process is repeated for a fixed number of iterations. It is computationally intensive and lacks ripple suppression characteristics. The flip-flop method does not compare well with any of the other techniques. It yields filters with the worst figures of merit for most of the design examples. However, it was applied successfully to the anti-reflection coating. The peak ripple for the anti-reflection filter in the 400 nm to 1100 nm wavelength band is 9.62 % compared to the inverse Fourier transform's 57.30 %. The genetic algorithm operates on the principle of "survival of the fittest". It is a stochastic procedure and yields quasi-random refractive index profiles. It excels with the antireflection coating. The peak ripple in the passband of the anti-reflection coating is 3.29%. The figure of merit for the anti-reflection coating designed with the genetic algorithm is 2.09.

Zhao, Lei = 介孔材料的光學應用和表面等離子體-熒光分子之間相互作用 / 趙磊. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Zhao, Lei = Jie kong cai liao de guang xue ying yong he biao mian deng li zi ti - ying guang fen zi zhi jian xiang hu zuo yong / Zhao Lei.

by Fung Chi Keung = 採用脈衝直流電源對靶濺射技術製備銦錫氧化物薄膜的硏究 / 馮志強. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / by Fung Chi Keung = Cai yong mai chong zhi liu dian yuan dui ba jian she ji shu zhi bei yin xi yang hua wu bo mo de yan jiu / Feng Zhiqiang. / Acknowledgements --- p.i / Abstract --- p.ii / 論文摘要 --- p.iii / Table of contents --- p.iv / List of figures --- p.viii / List of tables --- p.xii / Chapter Chapter 1 --- Introduction --- p.1-1 / Chapter 1.1 --- Genesis --- p.1-1 / Chapter 1.2 --- Aims and Objectives --- p.1-1 / Chapter 1.3 --- Layout of Thesis --- p.1-3 / References --- p.1-4 / Chapter Chapter 2 --- Literature Review --- p.2-1 / Chapter 2.1 --- Introduction to transparent conducting oxides (TCOs) --- p.2-1 / Chapter 2.2 --- Indium tin oxide (ITO) --- p.2-2 / Chapter 2.2.1 --- Use of ITO --- p.2-2 / Chapter 2.2.2 --- Structure and properties of ITO --- p.2-3 / Chapter 2.3 --- Properties of ITO films deposited by different growth techniques --- p.2-8 / Chapter 2.3.1 --- Sputtering --- p.2-9 / Chapter 2.3.2 --- Vacuum evaporation --- p.2-11 / Chapter 2.3.3 --- Spray pyrolysis --- p.2-11 / Chapter 2.3.4 --- Chemical vapor deposition (CVD) --- p.2-12 / Chapter 2.3.5 --- Reactive ion plating --- p.2-12 / Chapter 2.4 --- Contradictions in existing literature --- p.2-13 / References --- p.2-15 / Chapter Chapter 3 --- Thin Film Fabrication and Process --- p.3-1 / Chapter 3.1 --- Facing-target sputtering (FTS) --- p.3-1 / Chapter 3.2 --- Asymmetric bipolar pulsed DC power source --- p.3-3 / Chapter 3.2.1 --- Target poisoning --- p.3-3 / Chapter 3.2.2 --- Preferential sputtering --- p.3-4 / Chapter 3.2.3 --- Discussion --- p.3-4 / Chapter 3.3 --- Substrates --- p.3-6 / Chapter 3.3.1 --- Microscopic glass --- p.3-7 / Chapter 3.3.2 --- Corning 7059 glass --- p.3-8 / Chapter 3.3.3 --- Epitaxial growth --- p.3-8 / Chapter 3.3.3.1 --- Epitaxial lattice matching --- p.3-8 / Chapter 3.3.3.2 --- Yttrium stabilized zirconia (YSZ) --- p.3-9 / Chapter 3.3.3.3 --- Sapphire --- p.3-9 / Chapter 3.3.3.4 --- Silicon wafer --- p.3-11 / Chapter 3.3.4 --- Substrate cleaning --- p.3-11 / Chapter 3.4 --- Targets for the reactive sputtering of ITO films --- p.3-13 / Chapter 3.4.1 --- Indium Tin Oxide target (90wt% ln203 : 10wt% Sn04) --- p.3-14 / Chapter 3.4.2 --- Indium Tin alloy target (90wt% In : 10wt% Sn) --- p.3-14 / Chapter 3.5 --- Deposition conditions --- p.3-16 / Chapter 3.5.1 --- Sputter atmosphere --- p.3-16 / Chapter 3.5.2 --- Deposition pressure --- p.3-16 / Chapter 3.5.3 --- Deposition power --- p.3-17 / Chapter 3.5.4 --- Target to substrate distance --- p.3-17 / Chapter 3.5.5 --- Pulse frequency and pulse width --- p.3-17 / Chapter 3.6 --- Deposition --- p.3-17 / References --- p.3-19 / Chapter Chapter 4 --- Measurement and Analysis Techniques --- p.4-1 / Chapter 4.1 --- Resistivity measurement --- p.4-1 / Chapter 4.2 --- "Transmittance, reflectivity and absorption measurements" --- p.4-3 / Chapter 4.3 --- Thickness measurement --- p.4-4 / Chapter 4.4 --- "Crystal structure, surface morphology and roughness measurements" --- p.4-4 / Chapter 4.5 --- Photolithography --- p.4-7 / Chapter 4.6 --- Hall effect measurements --- p.4-8 / References --- p.4-10 / Chapter Chapter 5 --- Experimental results and discussions --- p.5-1 / Chapter 5.1 --- Effect of O2 partial pressure --- p.5-1 / Chapter 5.1.1 --- Deposition rate --- p.5-2 / Chapter 5.1.2 --- Electrical and optical properties --- p.5-4 / Chapter 5.1.3 --- Structure and orientation --- p.5-16 / Chapter 5.1.4 --- Surface morphology and roughness --- p.5-22 / Chapter 5.1.5 --- Conclusion --- p.5-29 / Chapter 5.2 --- Effect of substrate temperature --- p.5-29 / Chapter 5.2.1 --- Electrical and optical properties --- p.5-29 / Chapter 5.2.2 --- Structure and orientation --- p.5-44 / Chapter 5.2.3 --- Surface morphology and roughness --- p.5-49 / Chapter 5.2.4 --- Conclusion --- p.5-54 / Chapter 5.3 --- Effect of vacuum annealing --- p.5-54 / Chapter 5.3.1 --- Electrical and optical properties --- p.5-54 / Chapter 5.3.2 --- Conclusion --- p.5-59 / Chapter 5.4 --- Effect of different substrates --- p.5-59 / Chapter 5.4.1 --- Comparison of heteroepitaxial and polycrystalline ITO films --- p.5-60 / Chapter 5.4.2 --- Conclusion --- p.5-63 / Chapter 5.5 --- Effect of film thickness --- p.5-64 / Chapter 5.5.1 --- Film thickness calibration --- p.5-64 / Chapter 5.5.2 --- Electrical properties --- p.5-64 / Chapter 5.5.3 --- Conclusion --- p.5-67 / Chapter 5.6 --- Effect of deposition pressure --- p.5-68 / Chapter 5.6.1 --- Deposition rate --- p.5-68 / Chapter 5.6.2 --- Electrical properties --- p.5-70 / Chapter 5.6.3 --- Conclusion --- p.5-70 / Chapter 5.7 --- Effect of target pre-conditioning --- p.5-72 / Chapter 5.8 --- Conclusion --- p.5-72 / References --- p.5-74 / Chapter Chapter 6 --- Further works --- p.6-1 / Appendix I

by Yeung Mei Ki. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 122-127). / Text in English; abstracts in English and Chinese. / by Yeung Mei Ki. / Abstract --- p.i / 論文摘要 --- p.iii / Acknowledgements --- p.iv / Table of Contents --- p.v / List of Figures --- p.viii / List of Tables --- p.xi / Abbreviations --- p.xii / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Polymer light emitting devides --- p.1 / Chapter 1.1.1 --- Development history of PLEDs --- p.3 / Chapter 1.1.2 --- Basic structure of the PLEDs --- p.4 / Chapter 1.1.3 --- Operation principle of the PLEDs --- p.7 / Chapter 1.1.4 --- Electroluminescent (EL) polymers --- p.9 / Chapter 1.2 --- Research motivation and aim of study --- p.11 / Chapter 1.3 --- Thesis outline --- p.16 / Chapter Chapter 2 --- Instrumentation / Chapter 2.1 --- Thermal analysis --- p.18 / Chapter 2.1.1 --- Thermogravimetry (TG) --- p.19 / Chapter 2.1.2 --- Differential scanning calorimetry (DSC) --- p.22 / Chapter 2.2 --- Spectroscopic analysis --- p.27 / Chapter 2.2.1 --- Fourier transform infrared spectroscopy (FTIR) --- p.27 / Chapter 2.2.2 --- X-ray photoelectron spectroscopy (XPS) --- p.32 / Chapter 2.2.3 --- Photoluminescence spectroscopy (PL) --- p.36 / Chapter Chapter 3 --- Experimental metods to charaterize the elimination of / Chapter 3.1 --- Introduction --- p.41 / Chapter 3.2 --- Synthesis of the PPV precursor polymer --- p.43 / Chapter 3.3 --- Average molecular weight of the PPV precursor --- p.46 / Chapter 3.4 --- Thermal elimination of the precursor polymer --- p.48 / Chapter 3.5 --- Thermal stability of the PPV precursor polymer --- p.50 / Chapter 3.5.1 --- Sample preparation --- p.50 / Chapter 3.5.2 --- Experimental --- p.51 / Chapter 3.5.3 --- Results and discussion --- p.52 / Chapter 3.6 --- Structural changes of the precursor polymer during elimination --- p.57 / Chapter 3.6.1 --- Sample preparation --- p.57 / Chapter 3.6.2 --- Experimental --- p.58 / Chapter 3.6.3 --- Results and discussion --- p.58 / Chapter 3.7 --- Chemical composition of the precursor polymer upon elimination --- p.67 / Chapter 3.7.1 --- Sample preparation --- p.67 / Chapter 3.7.2 --- Experimental --- p.67 / Chapter 3.7.3 --- Results and discussion --- p.68 / Chapter 3.8 --- Effect of the conjugation length of the polymer on photoluminescence --- p.74 / Chapter 3.8.1 --- Sample preparation --- p.76 / Chapter 3.8.2 --- Experimental --- p.78 / Chapter 3.8.3 --- Results and discussion --- p.79 / Chapter 3.9 --- Conclusions --- p.89 / Chapter Chapter 4 --- Experimental methods to characterize the water absorption by PEDOT:PSS / Chapter 4.1 --- Introduction --- p.90 / Chapter 4.2 --- Determination of the water content of PEDOT:PSS at different relative humidity using TG --- p.93 / Chapter 4.2.1 --- Experimental --- p.94 / Chapter 4.2.2 --- Results and discussion --- p.96 / Chapter 4.3 --- Determination of bounded water content of PEDOT:PSS at different RH by DSC --- p.98 / Chapter 4.3.1 --- Experimental --- p.98 / Chapter 4.3.2 --- Results and discussion --- p.100 / Chapter 4.4 --- Determination of bounded water content of PEDOT:PSS at different RH by FTIR --- p.108 / Chapter 4.4.1 --- Experimental --- p.109 / Chapter 4.4.2 --- Results and discussion --- p.112 / Chapter 4.5 --- Conclusions --- p.118 / Chapter Chapter 5 --- Conclusions --- p.120 / References --- p.122

Chan Jacklynn = 摻近紅外染料溶凝膠薄膜之光學及激光性質研究 / 陳在琳. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 137-152). / Text in English; abstracts in English and Chinese. / Chan Jacklynn = Shan jin hong wai ran liao rong ning jiao bo mo zhi guang xue ji ji guang xing zhi yan jiu / Chen Zailin. / Abstract --- p.i / Acknowledgements --- p.v / Publications --- p.vii / Table of Contents --- p.viii / List of Figures --- p.xi / List of Tables --- p.xiv / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Sol-gel Glass Waveguides --- p.3 / Chapter 1.2 --- Ellipsometry --- p.7 / Chapter 1.3 --- Aim of this Research Work and Organization of Thesis --- p.12 / Chapter 2 --- Basics on Ellipsometry --- p.16 / Chapter 2.1 --- Principle of Ellipsometry --- p.17 / Chapter 2.1.1 --- Definition of Ellipsometric Parameters --- p.17 / Chapter 2.1.2 --- Configurations of an Ellipsometer --- p.22 / Chapter 2.2 --- Mathematical Representation of Ellipsometry --- p.26 / Chapter 2.2.1 --- Bulk Material Structure --- p.26 / Chapter 2.2.2 --- Single Layer Structure --- p.28 / Chapter 2.3 --- Parameterization of Optical Functions --- p.31 / Chapter 2.3.1 --- Optical Functions --- p.34 / Chapter 2.3.2 --- Regression Analysis --- p.38 / Chapter 3 --- Modification of Rotating-Polarizer-Analyzer Ellipsometer --- p.40 / Chapter 3.1 --- Principle of RPA System --- p.41 / Chapter 3.2 --- Optical Setup of RPA System --- p.45 / Chapter 3.3 --- Components of the System and Modification for Infrared Measurement --- p.47 / Chapter 3.3.1 --- Light Source --- p.47 / Chapter 3.3.2 --- Monochromator --- p.52 / Chapter 3.3.3 --- Polarizers and Analyzer --- p.53 / Chapter 3.3.4 --- Detector and Data Reduction --- p.54 / Chapter 3.4 --- Optical Alignment --- p.59 / Chapter 3.5 --- Alignment of the Azimuthal Angles of the Polarizers --- p.61 / Chapter 3.6 --- Calibration Procedure --- p.63 / Chapter 3.6.1 --- Calibration by Gold Film on Silicon --- p.63 / Chapter 3.6.2 --- Calibration by Silicon Dioxide Film on Silicon --- p.67 / Chapter 4 --- Near Infrared Dyes in Sol-gel Waveguides --- p.72 / Chapter 4.1 --- Sol-gel Process --- p.73 / Chapter 4.2 --- Near Infrared Dyes in Sol-gel Waveguides --- p.77 / Chapter 4.2.1 --- Development of Near Infrared Dyes --- p.77 / Chapter 4.2.2 --- Studies on Near Infrared Dye Solid State Laser --- p.79 / Chapter 5 --- Optical Properties of Dye-doped Sol-gel Waveguides --- p.83 / Chapter 5.1 --- Experimental Procedure --- p.84 / Chapter 5.1.1 --- Preparation of Samples --- p.84 / Chapter 5.1.1.1 --- Materials --- p.84 / Chapter 5.1.1.2 --- Procedure --- p.86 / Chapter 5.1.2 --- Discussion on Synthesis of Infrared Dye-doped Sol-gel Waveguides --- p.88 / Chapter 5.1.2.1 --- Choice of Solvents --- p.89 / Chapter 5.1.2.2 --- Thermal Treatment and Lifetime --- p.93 / Chapter 5.1.2.3 --- Necessity of Addition of GLYMO --- p.94 / Chapter 5.1.3 --- Sample Characterization --- p.96 / Chapter 5.2 --- Surface Morphology --- p.97 / Chapter 5.3 --- Optical Properties of Dye-doped Zirconia Organically Modified Silicate Waveguides --- p.100 / Chapter 5.3.1 --- Modeling of Ellipsometric Values --- p.101 / Chapter 5.3.2 --- Interpretation of the Modeling Results --- p.107 / Chapter 6 --- Amplified Spontaneous Emission Based on Sol-gel Waveguides --- p.109 / Chapter 6.1 --- Experimental Setup --- p.110 / Chapter 6.2 --- Features of ASE and Fluorescence --- p.112 / Chapter 6.3 --- Prolonged Thermal Treatment Effect on Light Emission --- p.119 / Chapter 6.3.1 --- Difference in Preparation of Samples --- p.121 / Chapter 6.3.2 --- Light Emission of Samples under Extended Thermal Treatment --- p.123 / Chapter 6.3.3 --- Directionality of the Emission --- p.125 / Chapter 6.3.4 --- Some Features of the Emission --- p.127 / Chapter 7 --- Conclusion and Recommendation --- p.133 / Chapter 7.1 --- Conclusion --- p.133 / Chapter 7.2 --- Recommendation --- p.135 / Bibliography --- p.137

Over the last 5 decades, the semiconductor industry has been well served by Si based technology due to its abundant availability, lower manufacturing cost, large wafer sizes and less complexity in fabrication. Over this period, electronic devices and integrated systems have been miniaturized by downscaling of the transistors. The miniaturization has been guided by the Moore's law where the numbers of transistors have doubled over every two years. However, the trend of transistor miniaturization is fast approaching its limit. Hence, alternate and innovative solutions are necessary to tackle this problem and this propels the research for finding novel materials with unique properties. The isolation of graphene, a single layer of graphite in 2004 had dramatically pioneered a new regime of research and investigation as a potential material to replace traditional Si. Graphene is the most widely studied two dimensional (2D) material exhibiting fascinating electronic, optoelectronic and electrochemical properties. Room temperature graphene has very high carrier mobility, a hundred times larger than that of Si, but it lacks a bandgap preventing its application in digital electronics. However, the advent of graphene initiated exploration of other 2D materials as a possible replacement for Si for future generation of electronic devices. Other 2D layered materials include transition metal dichalcogenides (TMDs), other layered metal chalcogenides, black phosphorus (BP), boron nitride (BN) etc which are also attractive due to fascinating electronic band structure and layer dependent properties that have demonstrated potential applications in optoelectronics and semiconductor devices. Metal chalcogenides are among the well-studied layered materials that have been isolated as high-quality and two-dimensional crystals. Among the 2D layered metal chalcogenide materials is tin selenide (SnSe), which belongs to group IV--VI that has attracted considerable attention due to its interesting structural and optical properties, hence it has potential applications in optoelectronics, photovoltaics, memory, energy storage, and catalysis. To date, SnSe films have been produced by exfoliation or chemical vapor deposition that produces flaky films. In this research, uniform, smooth and high quality SnSe thin films were grown over large area (5cm x 5cm) Si/SiO2 substrates using Atomic Layer Deposition (ALD). Films were grown over a temperature range of 350°C to 450°C, which exhibit p- type semiconductor characteristics. ALD is perfect for the growth of layered materials due to its precise controllability of film composition and thickness as the growth proceeds layer by layer. Structural and optical properties of the as-grown films were investigated using X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). These analyses show growth of 2 dimensional, orthorhombic phase films. Magnetic analysis shows a paramagnetic behavior. Back-gated transistors were fabricated for electrical characterization which showed p-type conductance, with an average hole mobility of 10 cm2/V.s and Ion/Ioff ratio of ~105.