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In recent years, there has been considerable interest in media which exhibit significant non-linear physical properties. The non-linear optical response of many materials has attracted a great deal of attention from the telecommunications industry owing to their possible use for signal processing applications. Also, applications such as thermal imaging depend ultimately upon the proficient operation of the active material within the device structure. Traditionally, inorganic materials such as lithium niobate and strontium barium niobate have been used for non-linear optics and infra-red detection. However, the last decade or so has exposed the potentially high efficiency offered by organic materials which, coupled to the ability to engineer their physical properties by subtle modifications at the molecular level, suggests an exciting and productive future. In order to maintain compatibility with existing integrated optics and display technologies, it is often useful to process the active compound in thin film form. The stringent symmetry requirements imposed upon the molecules and their organisation in the macroscopic structure necessitates the existence of non-centrosymmetric molecular structures for second-order non-linear applications such as those mentioned above. The Langmuir-Blodgett deposition technique enables such assemblies to be constructed by the sequential transfer of organic monomolecular layers from a liquid-air interface onto a solid substrate. The precise control of film thickness and molecular architecture afforded by the technique allow polar multilayer structures to be produced which possess the properties required for highly efficient second-order non-linear physical operation. This thesis describes the development of a series of novel organo-metallic complexes which possess the necessary molecular properties for LB deposition in addition to those required for the observation of a large non-linear response. The complexes offer substantially improved thermal stability over other LB materials, and are thus appealing to the industrial device engineer. Their physical properties have been systematically studied and related to their detailed molecular structure. In particular, optical second-harmonic generation studies have shown that they possess high molecular coefficients and have provided a launching stage for further development. Their high pyroelectric response has attracted much enthusiasm from both industry and academia because of their potential commercial exploitation in thermal imaging devices.

This thesis is a comparative study of nickel oxide based thin films for use as a counter electrode in a variable transmittance electrochromic device. Coatings have been prepared using anodic electrodeposition, colloidal precipitation and radio frequency (r.f.) sputtering. Systematic studies of the effect of deposition process parameters on optical and electrochromic properties of such films have been undertaken. Optimum conditions for the deposition of coatings deposited by colloidal and anodic deposition have been determined. A novel process for the colloidal deposition of electrochromic a-Ni(OH)2 coatings using a simple one dip process is reported. Also the electrochromic properties of coatings anodically deposited from aqueous solutions containing NiS04 and NH40H were improved by the addition of the non-ionic surfactant polyoxyethylene sorbitan monolaurate. Spectroscopic and electrochemical analytical techniques were used to identify the chemical composition of the coloured and bleached states. It was found using Fourier transform infra-red spectrophotometry (FTIR) that coatings deposited by anodic and colloidal deposition contained f3-Ni(OH)2 and a-Ni(OH)2 respectively in the as-deposited and transparent states. For coatings deposited by both techniques 13 or y-NiOOH was detected in the coloured state using FTIR. Using Raman spectroscopy, y-NiOOH was detected in the coloured state for coatings deposited by anodic deposition from solutions containing the additive polyoxyethylene sorbitan monolaurate. I3-Ni(OH)2 was also detected in the transparent state of r.f. sputtered coatings that were electrochemically cycled in 1M KOH(aq). Using cyclic voltammetry the oxidation of nickel hydroxide to the oxyhydroxide was detected during colouration for coatings produced using anodic electrodeposition, colloidal precipitation and r.f. sputtering (after cycling sputtered films for 1 hour in 1M KOH(aq)). This information has been compared for films prepared using the different deposition techniques to enable the respective colouration mechanisms to be elucidated. Prototype electrochromic devices have been constructed and their performances assessed. It can be concluded that nickel oxide based coatings can be used as suitable counter electrodes for hydrated electrochromic devices.

This thesis deals with electrical conductivity in thin films. Classical and quantum size effects in conductivity are discussed including some experimental evidence of quantum size effects. The component conductivity along the applied electric field of a thin film in a transverse magnetic field is developed in a density matrix method.

The deposition of WOx and FeOx thin films by reactive PLD and post-deposition annealing in an oxygen environment have been investigated. The influence of the deposition parameters on the growth and structure of WOx as well as the electronic and structural properties of FeOx thin films are presented. WOx thin films have been deposited onto native oxide Si (100) and SrTiO3 (100) substrates, whilst FeOx films were deposited onto glass and MgO (100). The films have been analysed using X-ray diffraction (XRD), texture pole figure analysis, X-ray reflectivity (XRR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM) and resistance vs temperature measurements. The WOx films deposited on both Si and SrTiO3 substrates were found to exhibit a dependence on the primary texture with fluence in the range of 5.3 J cm-2 to 14.7 J cm-2. The WOx films deposited on SrTiO3 were observed to exhibit a biaxial texture whilst the films on Si displayed a (002) WO3 out of plane fibre texture. The primary texture of the WOx films on SrTiO3 was observed to evolve from (200)/(020) WO3 to a single (002) WO3 texture with increasing fluence. The FeOx films deposited via reactive PLD onto glass substrates were found to exist in the Fe2O3 oxidation state for all parameters used. The production of Fe3O4 by post-deposition annealing of Fe films on glass and MgO (100) substrates in an oxygen environment is also presented. On both substrates it was necessary to use a two-stage anneal process to produce Fe3O4; an initial 175 °C oxygen anneal followed by a 500 °C vacuum anneal. The presence of Fe3O4 was confirmed by the existence of the Verwey transition at close to 120 K, during resistance vs temperature scans. The anneal parameters required to produce Fe3O4 are shown to be different for MgO substrates in comparison to glass.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfillment of the academic requirements for the degree of Master of Science. Johannesburg, March 2016. / Zinc oxide (ZnO) continues to receive widespread attention due to its excellent optical and electronic properties; it demonstrates the combined characteristics of high transmittance and electrical conductivity. Despite the tremendous drive for its application in optoelectronic devices, the full nature of the point defects and defect complexes have not been characterised comprehensively. In this work, luminescence characteristics of the intrinsic defects in ZnO thin films and the rare-earth ions Eu3+ and Tb3+ in ZnO powders are investigated under blue-laser excitation. The thin films used in this study were deposited using the radio-frequency magnetron sputtering method over a 2 hour duration under varied power and substrate bias conditions. The powders were synthesized by the chemical bath deposition method with dopant concentrations of 1.0 mol%. Grazing incidence X-ray diffraction (XRD) was used to determine the lattice properties of the samples. Photoluminescence studies were primarily conducted at room temperature (300 K) with the 457.9 nm, 476.5 nm and 488.0 nm laser lines as excitation sources. For the ZnO thin films, XRD patterns of a hexagonal wurtzite structure with a c/a ratio of about 1.60 and a u-parameter of 0.38 were obtained. Photoluminescence measurements show a broad emission band in the 500.0-900.0 nm range, centred at 656.0 nm. Annealed films yielded relatively more intense photoluminescence spectra than the as-prepared films. The intrinsic point defects and defect level transitions responsible for the broad emission are discussed. For the ZnO powders, the XRD patterns of the annealed samples of pristine ZnO, ZnO:Eu3+ and ZnO:Tb3+ are similarly consistent with a hexagonal wurtzite ZnO phase. Energy dispersive spectroscopy (EDS) confirmed the presence of the Eu3+ and Tb3+ dopants in the respective ZnO host while scanning electron microscopy (SEM) measurements showed the morphology of the sample powders. Photoluminescence spectra of pelletized samples, obtained in the 460.0-900.0 nm range, exhibit relatively intense Eu3+ and Tb3+ emission bands superimposed on a broad emission background. The RE3+ emission bands are attributed to the 5D0 → 7FJ (J = 0, 1, 2, 3, 4) and the 5D4 → 7FJ (J = 0, 1, 2, 3, 4, 5, 6) electronic transitions of Eu3+ and Tb3+, respectively, while the background emission is attributed to intrinsic defects. Crystal-field energy levels for the Eu3+ ion and the Tb3+ ion occupying a C3v symmetry site were deduced from fitting Gaussian curves to the RE3+ emission bands. Possible channels for transfer of energy from the intrinsic defects to Eu3+ and Tb3+ are discussed. / LG2017

by Au Wing Shing. / Parallel title in Chinese characters. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1992. / Includes bibliographical references (leaves 56-58). / Acknowledgements --- p.i / Abstract --- p.ii / Table of Content --- p.iii / Chapter CHATPER 1 : --- INTRODUCTION --- p.1 / Chapter CHAPTER 2 ： --- EXPERIMENTAL SET-UP / Chapter A. --- General Description --- p.4 / Chapter B. --- Vacuum System and Chamber --- p.6 / Chapter C. --- Target Rotation and Motor Connection --- p.7 / Chapter D. --- Substrate Heating and Temperature Control --- p.8 / Chapter E. --- Pressure and Flow Control --- p.9 / Chapter CHAPTER 3 ： --- THICKNESS AND COMPOSITION DISTRIBUTIONS OF FILMS DEPOSITED AT ROOM TEMPERATURE / Chapter A. --- Experimental Details --- p.10 / Chapter B. --- Shape of the Plume --- p.12 / Chapter C. --- Effect of Laser Fluence --- p.15 / Chapter D. --- Investigation of the Pb Deficiency in the Deposited Film --- p.24 / Chapter E. --- Effect of Oxygen Pressure --- p.27 / Chapter CHAPTER 4 ： --- TARGET MODIFICATION AND DEPOSITION RATE / Chapter A. --- Introduction --- p.34 / Chapter B. --- Experimental Details --- p.40 / Chapter C.i. --- Result 1 : Normal Incidence Case --- p.41 / Chapter ii. --- Result 2 : 45° Incidence Case --- p.42 / Chapter D. --- Discussion --- p.43 / Chapter CHAPTER 5 : --- HIGH TEMPERATURE GROWTH ON DIFFERRENT KINDS OF SUBSTRATES / Chapter A. --- Introduction --- p.45 / Chapter B. --- Experimental Details --- p.47 / Chapter C. --- High Temperature Growth / Chapter i. --- Films grown on MgO (100) --- p.49 / Chapter ii. --- Films grown on Spinel --- p.50 / Chapter iii. --- Films grown on c-plane Sapphire --- p.51 / Chapter D. --- Discussion --- p.52 / Chapter CHAPTER 6 ： --- OVERALL CONCLUSION AND FURTHER WORKS --- p.54 / References --- p.56 / Appendix1 --- p.59 / Appendix2 --- p.61

by Yun-hung Ng. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / by Yun-hung Ng. / Abstract --- p.ii / 論文摘要 --- p.iii / Acknowledgements --- p.iv / Table of Contents --- p.v / List of Figures --- p.ix / List of Tables --- p.xi / Chapter Chapter 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Background of Study --- p.1 / Chapter 1.2 --- General Properties of a-SiNx and a-SiOxNy --- p.1 / Chapter 1.3 --- Common Preparation Methods of a-SiNx and a-SiOxNy --- p.2 / Chapter 1.4 --- Applications of a-SiNx in Microelectronics --- p.4 / Chapter 1.5 --- Applications of a-SiOxNy in Microelectronics --- p.6 / References --- p.8 / Chapter Chapter 2 --- METHODOLOGY --- p.10 / Chapter 2.1 --- Introduction --- p.10 / Chapter 2.2 --- Mott Rule --- p.10 / Chapter 2.3 --- Random Mixture Model --- p.11 / Chapter 2.4 --- Random Bonding Model --- p.12 / Chapter 2.5 --- Hasegawa Model --- p.15 / References --- p.20 / Chapter Chapter 3 --- INSTRUMENTATION --- p.21 / Chapter 3.1 --- X-ray Photoelectron Spectroscopy (XPS) --- p.21 / Chapter 3.1.1 --- Fundamental Theory of XPS --- p.21 / Chapter 3.1.2 --- Qualitative Analysis using XPS --- p.25 / Chapter 3.1.2.1 --- Chemical Shift --- p.25 / Chapter 3.1.2.2 --- Angular Effect on XPS --- p.28 / Chapter 3.1.2.3 --- Valence Band Investigation --- p.28 / Chapter 3.1.3 --- Quantitative Analysis using XPS --- p.30 / Chapter 3.1.4 --- Instrumental Setup of XPS --- p.33 / Chapter 3.2 --- Ultraviolet Photoelectron Spectroscopy --- p.37 / Chapter 3.2.1 --- Basic Theory of UPS --- p.37 / Chapter 3.2.2 --- Instrumentation --- p.38 / References --- p.41 / Chapter Chapter 4 --- SHORT RANGE ORDER OF a-SiNx --- p.42 / Chapter 4.1 --- Sample Preparation --- p.42 / Chapter 4.2 --- XPS Analysis of a-SiNx --- p.43 / Chapter 4.2.1 --- Angle Resolved XPS Analysis --- p.43 / Chapter 4.2.2 --- RB Model and RM Model Simulation of a-SiNx --- p.43 / Chapter 4.2.3 --- Intermediate Mixture (IM) Model --- p.50 / Chapter 4.2.4 --- Valence Band Structure of a-SiNx --- p.51 / Chapter 4.3 --- Raman Measurements --- p.54 / Chapter 4.4 --- Photoluminescence of a-SiNx --- p.54 / Chapter 4.5 --- Large Scale Potential Fluctuations in a-SiNx --- p.56 / Chapter 4.6 --- Conclusion --- p.61 / References --- p.62 / Chapter Chapter 5 --- MOTT RULE VERIFICATION OF a-SiOxNy --- p.65 / Chapter 5.1 --- Sample Preparation --- p.65 / Chapter 5.2 --- Validity of Mott Rule on a-SiOxNy --- p.66 / Chapter 5.3 --- Conclusion --- p.73 / References --- p.74 / Chapter Chapter 6 --- SHORT RANGE ORDER OF a-SiOxNy --- p.75 / Chapter 6.1 --- Angle Resolved XPS Analysis --- p.75 / Chapter 6.2 --- Random Bonding Model Simulation of a-SiOxNy --- p.75 / Chapter 6.3 --- Conclusion --- p.79 / References --- p.82 / Chapter Chapter 7 --- CONCLUSIONS --- p.83

by Leung Chi Hung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / by Leung Chi Hung. / Acknowledgments --- p.i / Abstract --- p.ii-iii / Table of Contents --- p.iv-v / Figures Caption --- p.vi-xii / Tables Caption --- p.xiii / Chapter 1. --- Introduction / Chapter 1.1 --- "Magnetoresistance (MR),Giant Magnetoresistance (GMR),Colossal Magnetoresistance (CMR) and Their Applications" --- p.1-1 / Chapter 1.2 --- Colossalmagnetoresistance Effect in LCMO --- p.1-5 / Chapter 1.3 --- Significance of Ultra-Sharp Metal-Semiconductor Transition LCMO Thin Film --- p.1-12 / Chapter 1.4 --- The Use of Silver in the YBCO --- p.1-14 / Chapter 1.5 --- Previews --- p.1-15 / Chapter 1.6 --- References --- p.1-17 / Chapter 2. --- Epitixial Growth of Single-Crystal LCMO Thin Film by FTS method / Chapter 2.1 --- Facing-Target Sputtering Method --- p.2-1 / Chapter 2.2 --- Fabrication of LCMO Targets --- p.2-4 / Chapter 2.3 --- Deposition of the LCMO Thin Film / Chapter 2.3.1 --- Deposition Condition --- p.2-6 / Chapter 2.3.2 --- Deposition Process --- p.2-9 / Chapter 2.4 --- X-ray Diffraction Studies and Surface Morphology --- p.2-11 / Chapter 2.5 --- M-S Transition of LCMO Thm Film --- p.2-15 / Chapter 2.6 --- Discussions --- p.2-19 / Chapter 3. --- The Role of Silver in LCMO / Chapter 3.1 --- Reaction between Ag and LCMO --- p.3-1 / Chapter 3.2 --- Grain Size and Transition Temperature in Bulk LCMO --- p.3-9 / Chapter 3.3 --- Improving the Sharpness of Metal - Semiconductor Transition and Crystallinity of LCMO Film --- p.3-15 / Chapter 3.4 --- Stabilization of the LCMO Structure --- p.3-21 / Chapter 3.5 --- Discussions --- p.3-25 / Chapter 4 --- Epitaxial Growth of the Ultra-Sharp Metal-Semiconductor Transition LCMO Thin Film / Chapter 4.1 --- Synthesis Process of the Ultra-Sharp Metal-Semiconductor Transition LCMO Thin Films --- p.4-1 / Chapter 4.2 --- Resistivity and Magnetoresistance --- p.4-6 / Chapter 4.3 --- Thermal Annealing Effects / Chapter 4.3.1 --- Oxygen Annealing Effect --- p.4-15 / Chapter 4.3.1 --- High Pressure Annealing Effect --- p.4-20 / Chapter 4.3.2 --- Vacuum Annealing Effect --- p.4-23 / Chapter 4.4 --- Surface Morphology and Characterization --- p.4-27 / Chapter 4.5 --- Discussions --- p.4-37

Throughout this work several thin film resists have been studied with substantial focus on HafSOx and SU-8. The study of HafSOx has granted more insight into how inorganic, spin coated films form and react under the electron beam. These films have been shown to form a thin dense crust at the surface that could have interesting implications in the interaction of the electrons. Continuing to further understand the electron interactions within the resist, low voltage patterns were created allowing the accelerating voltage to be matched to the film. With this general knowledge, higher resolution films can be constructed with shorter patterning times. Both resists complement each other in that HafSOx produces incredibly thin, dense structures to be formed with features below 10 nm in all dimensions. SU-8 allows micron thick features to be created over several millimeters. This flexibility in feature size enabled the creation of large fractals that could improve neuron binding to artificial retina down to the smallest fractals reported that are interesting for their applications as antennas. The final facet of this work involved looking at other methods of making structures. This was done through adding differing salts to organic molecules that stack into unique crystals. This dissertation includes previously published co-authored material.