Positron studies of defects in thin films and semiconductors are reviewed. The results obtained from experimental studies of Doppler broadening of annihilation radiation (DBAR) from variable energies are presented. Normalisation methods for the DBAR parameters S and W have been developed, allowing for direct comparisons of the results for different samples taken over long periods of time. The evaluation of the P:V parameter, the peak-to-valley ratio in a full annihilation spectrum, has been improved via a correction method that produced a fourfold increase in sensitivity to o-Ps annihilation. The spectrum ratio curve technique was improved and developed to investigate the chemical composition of the environment surrounding a positron-trapping defect. By fitting to multiple-element and/or defect-type responses the percentage of that particular element or defect contained within the sample could be found. Ratio curves were found to rely on the positron affinity to different vacancy types. Beam-based Doppler broadening spectroscopy, variable-energy positron annihilation spectroscopy (VEPAS), was used as a probe of oxide film and film/substrate interface characteristics. Different film growth methods were found to play a significant role in defining the features of films and their interfaces. Vacancies have a profound effect on the properties of semiconductor-type devices. A range of different structures and the effects of implantation have been investigated. VEPAS has been found to be useful in studying the more exotic types of materials, silica aerogel and niobium.

Chiral nematic thin films containing responsive dopants have previously been considered as sensors and dosimeters. Some systems have been developed, with mixed results. The investigation so far has been piecemeal, with little attention paid towards understanding the properties that govern how these sensors operate. By carefully considering these properties, we believe that it is possible to predict the effectiveness of a sensor, and therefore a framework can be established which would allow only sensors with significant potential to be investigated. The applications of a variety of chiral nematic thin films incorporating responsive dopants is modelled and then investigated experimentally. The systems chosen for investigation were selected using the criteria of commercial potential and synthetic simplicity. In each case it was found that the behaviour of these systems could be predicted well from simple experimental data. The systems chosen for investigation were judged on the basis of two key criteria: They must be systems that deal with a target that is of commercial interest, so that performance expectations for 'real-life' applications can be given at the start of the research process. They must be manufactured only using materials and processes that are commercially available. These limitations were chosen to highlight the conditions under which such a model would be expected to operate. In this work, a successful model that predicts sensors behaviour from basic experimental information was developed and shown to match well with experimental results. In the process, three new sensing systems were developed, all with potential commercial significance. Additionally, some observations regarding the methods of operation which are most likely to result in high sensitivity and low cross-sensitivity have been made.

by Hu Guangda. / "June 2000." / The numerals in the title are subscript. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (p. 131-141). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

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Lau Wai Cheung = 以低能氫離子形成具多官能團的交聯聚合物薄膜 / 劉慧璋. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / Lau Wai Cheung = Yi di neng qing li zi xing cheng ju duo guan neng tuan de jiao lian ju he wu bo mo / Liu Huizhang. / Abstract --- p.ii / Abstract (Chinese) --- p.iii / Acknowledgements --- p.iv / Table of Contents --- p.v / List of Figures --- p.xi / List of Tables --- p.xv / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.1.1 --- Polymer properties --- p.1 / Chapter 1.1.2 --- Polymer films --- p.2 / Chapter 1.2 --- Basic Idea of the study --- p.3 / Chapter 1.2.1 --- Previous works --- p.3 / Chapter 1.2.2 --- Related works --- p.4 / Chapter 1.2.3 --- Computational analysis --- p.5 / Chapter 1.2.4 --- Present studies --- p.7 / Chapter 1.3 --- Polymer surface modification techniques --- p.7 / Chapter 1.4 --- Preparation of cross-linked films --- p.9 / Chapter 1.4.1 --- Preparation of films --- p.9 / Chapter 1.4.2 --- Treatment of films --- p.10 / Chapter 1.4.3 --- Formation of the polymer network on films --- p.10 / Chapter 1.5 --- Analysis methods of films --- p.12 / Chapter 1.5.1 --- Film analysis by XPS --- p.12 / Chapter 1.5.2 --- Film analysis by AFM --- p.14 / Chapter 1.6 --- Polymer films with desired functionalities --- p.15 / Chapter 1.6.1 --- Film properties with desired functionalities --- p.15 / Chapter 1.6.2 --- Films with hydroxyl and carboxyl functionalities --- p.16 / Chapter 1.6.3 --- Films with mixed functionalities --- p.17 / Chapter 1.7 --- Goal of the present study --- p.17 / Chapter 1.7.1 --- Objective of this thesis --- p.17 / Chapter 1.7.2 --- Possible applications --- p.18 / Chapter 1.8 --- References for Chapter1 --- p.19 / Chapter CHAPTER 2 --- EXPERIMENTATION --- p.24 / Chapter 2.1 --- Introduction --- p.24 / Chapter 2.2 --- Sample preparation --- p.24 / Chapter 2.2.1 --- Preparation of polymer solutions --- p.24 / Chapter 2.2.2 --- Preparation of cleaned surfaces --- p.25 / Chapter 2.2.3 --- Spin coating --- p.26 / Chapter 2.2.4 --- Confirmation of Polymer network --- p.26 / Chapter 2.3 --- Low Energy Ion Beam (LEIB) system --- p.27 / Chapter 2.3.1 --- Principle --- p.27 / Chapter 2.3.2 --- Function of each component --- p.31 / Chapter 2.3.2.1 --- Ion source --- p.31 / Chapter 2.3.2.2 --- Einzel focusing lenses --- p.31 / Chapter 2.3.2.3 --- Deflectors --- p.32 / Chapter 2.3.2.4 --- Wien Filter --- p.32 / Chapter 2.3.2.5 --- Decelerator --- p.35 / Chapter 2.3.2.6 --- Target chamber and dose estimation --- p.35 / Chapter 2.4 --- X-ray Photoelectron Spectrometer (XPS) --- p.36 / Chapter 2.4.1 --- Principle --- p.36 / Chapter 2.4.2 --- Qualitative analysis --- p.37 / Chapter 2.4.2.1 --- Survey spectrum --- p.37 / Chapter 2.4.2.2 --- Core level spectrum --- p.38 / Chapter 2.4.2.3 --- Valence band spectrum --- p.38 / Chapter 2.4.2.4 --- Line shifts --- p.39 / Chapter 2.4.2.5 --- Lineshapes --- p.39 / Chapter 2.4.3 --- Quantitative Analysis --- p.40 / Chapter 2.4.3.1 --- Atomic concentration --- p.40 / Chapter 2.4.3.2 --- Layer thickness --- p.40 / Chapter 2.4.3.3 --- Curve fitting --- p.41 / Chapter 2.5 --- Ultrahigh Vacuum (UHV) System --- p.42 / Chapter 2.6 --- Other instruments --- p.42 / Chapter 2.7 --- References for Chapter2 --- p.43 / Chapter CHAPTER 3 --- POLY (ACRYLIC ACID) BOMBARDMENT BY LOW ENERGY H+ IONS --- p.45 / Chapter 3.1 --- Basic modeling and analysis method --- p.45 / Chapter 3.1.1 --- Peak fitting before bombardment --- p.45 / Chapter 3.1.2 --- Analysis of PVA surface after bombardment --- p.47 / Chapter 3.1.2.1 --- Peak fitting after bombardment --- p.47 / Chapter 3.1.2.2 --- Mechanism of PAA during bombardment --- p.48 / Chapter 3.1.2.3 --- Identification of the new component after bombardment --- p.50 / Chapter 3.2 --- Surface reaction with impact energy of 10 eV --- p.52 / Chapter 3.2.1 --- Cross-linking with different doses --- p.52 / Chapter 3.2.2 --- Effect of surface functionality with different ion doses --- p.57 / Chapter 3.3 --- Surface reaction with different impact energies --- p.59 / Chapter 3.3.1 --- Cross-linking with different impact energies --- p.59 / Chapter 3.3.2 --- Effect on surface functionality with different impact energies --- p.64 / Chapter 3.4 --- Surface reaction with impact energy of 1 eV --- p.66 / Chapter 3.4.1 --- Formation of a cross-linked polymer network using PAA --- p.66 / Chapter 3.4.2 --- Effect of surface functionality with different ion doses --- p.68 / Chapter 3.5 --- Chapter summary --- p.70 / Chapter 3.6 --- References for Chapter3 --- p.71 / Chapter CHAPTER 4 --- THE MECHANISM OF POLY (ACRYLIC ACID) BOMBARDMENT --- p.72 / Chapter 4.1 --- Surface reaction of PAA after bombardment --- p.72 / Chapter 4.1.1 --- Introduction --- p.72 / Chapter 4.1.2 --- Formation of ester group --- p.73 / Chapter 4.1.3 --- Loss of carbon dioxide --- p.73 / Chapter 4.1.4 --- Regeneration of carboxylic acid --- p.74 / Chapter 4.2 --- Analysis of the surface after bombardment --- p.74 / Chapter 4.2.1 --- Loss of oxygen --- p.74 / Chapter 4.2.2 --- Remaining un-reacted carboxyl acid --- p.75 / Chapter 4.3 --- Chapter summary --- p.80 / Chapter 4.4 --- References for Chapter4 --- p.81 / Chapter CHAPTER 5 --- POLY (VINYL ALCOHOL) BOMBARDMENT AND MECHANISM BY LOW ENERGY H+ IONS --- p.82 / Chapter 5.1 --- Basic modeling and analysis method --- p.82 / Chapter 5.1.1 --- Peak fitting before bombardment --- p.82 / Chapter 5.1.2 --- Analysis of PVA surface after bombardment --- p.84 / Chapter 5.1.2.1 --- Peak fitting after bombardment --- p.84 / Chapter 5.1.2.2 --- Mechanism of PVA during bombardment --- p.85 / Chapter 5.1.2.3 --- Identification of the new component after bombardment --- p.86 / Chapter 5.2 --- Surface reaction of PVA after bombardment --- p.88 / Chapter 5.2.1 --- Formation of a cross-linked polymer network using PVA --- p.88 / Chapter 5.2.2 --- Effect of dosage on the surface functionality of PVA at 10eV bombardment --- p.89 / Chapter 5.2.3 --- Remaining un-reacted hydroxyl group --- p.92 / Chapter 5.3 --- Chapter summary --- p.96 / Chapter 5.4 --- References for Chapter5 --- p.97 / Chapter CHAPTER 6 --- CONTROLLED FABRICATION OF POLYMER THIN FILMS WITH MULTIPLE FUNCTIONAL GROUPS --- p.98 / Chapter 6.1 --- Introduction --- p.98 / Chapter 6.2 --- Hydrogen bonding effect --- p.99 / Chapter 6.3 --- Analysis of mixed PVA and PAA before bombardment --- p.101 / Chapter 6.2.1 --- Peak fitting before bombardment --- p.101 / Chapter 6.2.2 --- Quantitative analysis before bombardment --- p.103 / Chapter 6.4 --- Analysis of mixed PVA and PAA after bombardment --- p.104 / Chapter 6.4.1 --- Peak fitting after bombardment --- p.104 / Quantitative analysis after bombardment --- p.107 / Chapter 6.4 --- Chapter summary --- p.110 / Chapter CHAPTER 7 --- CONCLUSION --- p.111 / Chapter 7.1 --- Summary --- p.111 / Chapter 7.2 --- Future works --- p.112

by Law Siu Wah = 超薄薄膜的應變和記憶效應 / 羅紹華. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / by Law Siu Wah = Chao bo bo mo de ying bian he ji yi xiao ying / Luo Shaohua. / Acknowledgement --- p.i / Abstract --- p.ii / 論文摘要 --- p.iv / Table of contents --- p.v / List of Figures --- p.viii / List of Tables --- p.xii / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Magnetoresistance (MR) --- p.1 / Chapter 1.1.1 --- Colossal magnetoresistance (CMR) in rare-earth manganites --- p.2 / Chapter 1.1.2 --- Double exchange mechanism --- p.3 / Chapter 1.1.3 --- Jahn-Teller effect --- p.6 / Chapter 1.1.4 --- Tolerance factor --- p.8 / Chapter 1.1.5 --- The effect of doping --- p.10 / Chapter 1.2 --- Our motivation --- p.12 / Chapter 1.3 --- Scope of this thesis work --- p.12 / References --- p.14 / Chapter Chapter 2 --- Experimental methods / Chapter 2.1 --- Thin film deposition --- p.16 / Chapter 2.1.1 --- Facing Target Sputtering (FTS) --- p.16 / Chapter 2.1.2 --- Vacuum system --- p.19 / Chapter 2.2 --- Annealing systems --- p.20 / Chapter 2.2.1 --- Oxygen annealing system --- p.20 / Chapter 2.2.2 --- Vaccum annealing system --- p.21 / Chapter 2.3 --- Characterization --- p.22 / Chapter 2.3.1 --- Profilometer --- p.22 / Chapter 2.3.2 --- X-ray diiffraction (XRD) --- p.22 / Chapter 2.3.3 --- Resistance measurement --- p.24 / References --- p.25 / Chapter Chapter 3 --- Expitaxial growth of La0.67Ca0.33MnO3 single layer thin film / Chapter 3.1 --- Fabrication and characteristics of La0.67Ca0.33MnO3 target --- p.26 / Chapter 3.2 --- Substrate materials --- p.31 / Chapter 3.3 --- Epiaxial growth of LCMO thin film --- p.33 / Chapter 3.3.1 --- Deposition conditions --- p.33 / Chapter 3.3.2 --- Deposition procedure --- p.35 / Chapter 3.3.3 --- Oxygen annealing effect --- p.36 / References --- p.41 / Chapter Chapter 4 --- Strain effect in expitaxial growth of La0. 67Ca0 .33MnO3 thin films / Chapter 4.1 --- Introduction --- p.42 / Chapter 4.2 --- Preparation of LCMO ultra-thin film on different substrates --- p.45 / Chapter 4.2.1 --- Sample preparation --- p.45 / Chapter 4.2.2 --- Oxygen annealing treatment --- p.45 / Chapter 4.3 --- Resistance measurement --- p.50 / Chapter 4.3.1 --- Thickness effect --- p.50 / Chapter 4.3.2 --- Strain effect --- p.63 / Chapter 4.4 --- Discussions --- p.68 / References --- p.69 / Chapter Chapter 5 --- Memory effect and thermal effect of ultra-thin La0.67Ca0.33MnO3 films / Chapter 5.1 --- Introduction --- p.71 / Chapter 5.2 --- Sample description and measurement method --- p.72 / Chapter 5.3 --- Memory effect and thermal effect --- p.73 / Chapter 5.4 --- Discussion --- p.77 / References --- p.80 / Chapter Chapter 6 --- Conclusion / Chapter 6.1 --- Conclusion --- p.81 / Chapter 6.2 --- Future work --- p.82

archives@tulane.edu / Silicon-based block copolymers have gained prominence because of their inherent ability to self-assemble at the low molecular weight. By utilizing this vital factor, we synthesize poly(vinylmethylsiloxane-block-methyl methacrylate) (PVMS-b-PMMA) intending to create small characteristic features with the potential application for lithography and membrane filtration. The polymer is made by a combination of anionic synthesis of PVMS, ATRP (atom radical transfer polymerization) of PMMA, and then cojoining the end-group functionalized blocks with a “click” reaction. After synthesis, thin films (10-100 nm) were self-assembled to form structures aligned perpendicular to the substrate. The morphology was observed by atomic force microscopy, grazing incidence small-angle X-ray scattering (GISAXS), and transmission electron microscopy (TEM). Additionally, the hydrophobicity of PVMS prompted us to develop a coating on microporous membrane supports for separation of water-in-oil mixtures. The PVMS was used as an effective coating to prevent fouling while maintaining high selectivity for both water-in-toluene and water-in-decane emulsion in gravity-based filtration. Finally, cyclic block copolymers (BCPs) have garnered increased attention because of their unique structure, which differs from linear BCPs due to a lack of end groups. This feature in combination with the high segregation strength of silicon-based polymers is desirable for nanolithography. Thus, we synthesized a new class of silicon-based cyclic polymer, cyclic PVMS-b-PMMA, intending to later understand the impact of topology on phase behavior, domain spacing, and nanoconfinement in thin films. / 1 / Baraka Lwoya

acase@tulane.edu / 1 / Sijun Luo

Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.