Cheng, Kai Hong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 134-141). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.iv / Table of Contents --- p.v / List of Figures --- p.viii / List of Tables --- p.xix / Chapter iii. --- Table of Contents / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Semiconductor spintronics --- p.1 / Chapter 1.1.1 --- Overview --- p.1 / Chapter 1.2 --- Dilute magnetic semiconductors (DMS) --- p.2 / Chapter 1.2.1 --- Historical background --- p.3 / Chapter 1.2.2 --- Their importance and significance --- p.4 / Chapter 1.2.3 --- Material systems showing room temperature ferromagnetism --- p.5 / Chapter 1.3 --- Cobalt (iron)-doped titanium dioxide as DMS --- p.7 / Chapter 1.3.1 --- Structures and properties of titanium dioxide --- p.8 / Chapter 1.3.2 --- Various preparation techniques of cobalt (iron)-doped titanium dioxide --- p.10 / Chapter 1.3.3 --- This thesis --- p.13 / Chapter Chapter 2 --- Sample Preparation and Characterization Techniques --- p.14 / Chapter 2.1 --- Sample preparation --- p.14 / Chapter 2.1.1 --- RF magnetron sputtering --- p.14 / Chapter 2.1.2 --- MEVVA ion implantation --- p.17 / Chapter 2.1.3 --- Sample preparation conditions --- p.19 / Chapter 2.2 --- Characterization techniques --- p.24 / Chapter 2.2.1 --- Structural characterization --- p.24 / Chapter 2.2.1.1 --- Rutherford backscattering spectrometry (RBS) --- p.24 / Chapter 2.2.1.2 --- X-ray diffraction (XRD) --- p.26 / Chapter 2.2.1.3 --- X-ray photoelectron spectroscopy (XPS) --- p.28 / Chapter 2.2.1.4 --- Transmission electron microscopy (TEM) --- p.31 / Chapter 2.2.2 --- Vibrating sample magnetometry (VSM) --- p.33 / Chapter 2.2.3 --- Temperature varying resistivity measurements --- p.35 / Chapter Chapter 3 --- Characterization of Titanium Dioxide Samples --- p.40 / Chapter 3.1 --- RBS results --- p.40 / Chapter 3.2 --- XRD results --- p.43 / Chapter 3.3 --- XPS results --- p.47 / Chapter 3.4 --- Summary --- p.51 / Chapter Chapter 4 --- Characterization of Cobalt-implanted Titanium Dioxide Sample --- p.53 / Chapter 4.1 --- Cobalt dose dependence --- p.53 / Chapter 4.1.1 --- RBS results --- p.53 / Chapter 4.1.2 --- XRD results --- p.65 / Chapter 4.1.3 --- VSM results --- p.69 / Chapter 4.1.4 --- Temperature varying resistivity measurements --- p.75 / Chapter 4.2 --- Effects of annealing temperature --- p.77 / Chapter 4.2.1 --- RBS results --- p.77 / Chapter 4.2.2 --- XRD results --- p.79 / Chapter 4.2.3 --- XPS results --- p.83 / Chapter 4.2.4 --- TEM results --- p.88 / Chapter 4.2.5 --- VSM results --- p.91 / Chapter 4.2.6 --- Temperature varying resistivity measurements --- p.97 / Chapter 4.3 --- Summary --- p.99 / Chapter Chapter 5 --- Characterization of Iron-implanted Titanium Dioxide Samples --- p.101 / Chapter 5.1 --- Iron dose dependence --- p.101 / Chapter 5.1.1 --- RBS results --- p.101 / Chapter 5.1.2 --- XRD results --- p.107 / Chapter 5.1.3 --- VSM results --- p.110 / Chapter 5.1.4 --- Temperature varying resistivity measurements --- p.114 / Chapter 5.2 --- Effects of annealing temperature --- p.116 / Chapter 5.2.1 --- RBS results --- p.116 / Chapter 5.2.2 --- XRD results --- p.117 / Chapter 5.2.3 --- VSM results --- p.119 / Chapter 5.2.4 --- Temperature varying resistivity measurements --- p.121 / Chapter 5.3 --- Summary --- p.122 / Chapter Chapter 6 --- Conclusion and future work --- p.125 / Appendices --- p.127 / Bibliography --- p.134 / Publications --- p.141 / Chapter iv. --- List of Figures / Fig. 1.1 Crystal structures for two most stable polymorphs of TiO2: (a) anatase; and (b) rutile --- p.9 / Fig. 2.1 Schematic of RF sputtering system --- p.15 / Fig. 2.2 Motion of electrons emitted for the target surface (a) in the applied magnetic field (-z direction); (b) in the applied electric field (-y direction) and magnetic field (-z direction) --- p.16 / Fig. 2.3 Schematic of the implanter with the MEVVA ion source --- p.17 / Fig. 2.4 The TRIM ion distribution profile of Co atoms in anatase TiO2 by implantation to a Co dose of 2.2 x 1016 cm-2 at an extraction voltage of 65 kV --- p.21

In addition, through a simple post-thermal treatment of TiO2 thin films on glass with trifluoroacetic acid (TFA), the thin films showed enhancement in the photocatalytic decomposition of acetone in air. XPS, FTIR and PL results revealed that the TFA complex bound on the surface of TiO 2 acted as an electron scavenger, and thus reduced the recombination of photo-generated electrons and holes. / Part I. TiO2 films on stainless steel prepared by dip coating in a nonionic microemulsion solution were investigated. These thin films have been shown to have much higher photocatalytic activity than films on glass substrates. XPS showed that Fe3+ and Fe 2+ ions, which were diffused from stainless steel substrate into TiO 2 films during high temperature calcination, behaved as dopants to significantly affect its photocatalytic activity of the films. The TiO2 films also exhibited excellent photo-induced hydrophilicity and antibacterial effect on the sterilization of Bacillus pumilus. / Part II. New approaches have been developed for the fabrication of visible light photocatalysts. MoS2 and WS2 were coupled to TiO2 by an in situ photo-reduction deposition method, taking advantage of the reducing power of TiO2 particles. The synthesis of CdSe sensitized TiO2 using an ultrasound-driven approach was also reported. The photocatalytic degradation of methylene blue and 4-chlorophenol was employed to evaluate their visible light photocatalytic activity. The small band gap semiconductors acting as photo-sensitizers not only extended the spectral response of TiO2 to the visible region but also improved their photocatalytic efficiency. The blue shift in the absorption onset confirmed the size-quantization of photosensitizers, which altered the conduction and valence band levels in the coupled semiconductor systems making it possible to utilize visible light in photocatalysis. (Abstract shortened by UMI.) / Two important aspects of the TiO2 photocatalysis were studied in this thesis. The first part reports on the improvement of photocatalytic performance of TiO2 films through approaches such as post-thermal treatment, surface modification and metal doping. The second part describes the fabrication of visible light TiO2 photocatalyts by means of coupling with small band gap semiconductor photo-sensitizers and non-metal doping. / Ho Wing-kei. / "May 2005." / Adviser: Jimmy C. Yu. / Source: Dissertation Abstracts International, Volume: 67-01, Section: B, page: 0294. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / 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, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Thesis (Ph.D.)--North Carolina State University, 2008. / Adviser: Ollis, David F. Includes bibliographical references.

Tang Hung Yuk. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 71-79). / Abstracts in English and Chinese. / ABSTRACT --- p.i / DECLARATION --- p.iii / ACKNOWLEDGEMENT --- p.iv / TABLE OF CONTENTS --- p.v / LIST OF TABLES --- p.viii / LIST OF FIGURES --- p.ix / Chapter CHAPTER ONE: --- INTRODUCTION --- p.1 / Chapter 1.1 --- Fundamentals of TiO2 --- p.1 / Chapter 1.2 --- Application of TiO2 --- p.5 / Chapter 1.3 --- Scope of Work --- p.11 / Chapter CHAPTER TWO: --- DISINFECTION BY UV IRRADIATED TiO2 --- p.14 / Chapter 2.1 --- Introduction --- p.14 / Chapter 2.2 --- Experimental --- p.19 / Chapter 2.2.1 --- Materials --- p.19 / Chapter 2.2.2 --- Preparation of TiO2 films --- p.19 / Chapter 2.2.3 --- Culture of microorganisms --- p.20 / Chapter 2.2.4 --- Bactericidal activities --- p.21 / Chapter 2.2.5 --- Photocatalytic experiment to degrade acetone in gas phase --- p.21 / Chapter 2.2.6 --- Photocatalytic experiment to degrade rhodamine B in aqueous phase --- p.22 / Chapter 2.2.7 --- Characterization --- p.23 / Chapter 2.3 --- Results and Discussions --- p.25 / Chapter 2.3.1 --- Bactericidal activity --- p.25 / Chapter 2.3.2 --- Photocatalytic activity --- p.34 / Chapter 2.3.3 --- Thickness and transmittance of Ti〇2 films --- p.37 / Chapter 2.3.4 --- Surface morphology and roughness of thin films --- p.40 / Chapter 2.3.5 --- Crystalline phase and crystallite size of thin films --- p.42 / Chapter 2.3.6 --- XPS study --- p.43 / Chapter CHAPTER THREE: --- DISINFECTION BY VISIBLE IRRADIATED TiO2 --- p.47 / Chapter 3.1 --- Introduction --- p.47 / Chapter 3.2 --- Experimental --- p.58 / Chapter 3.2.1 --- Materials --- p.58 / Chapter 3.2.2 --- Preparation of TiO2 films --- p.58 / Chapter 3.2.3 --- Culture of microorganisms --- p.59 / Chapter 3.2.4 --- Bactericidal activity --- p.60 / Chapter 3.3 --- Results and discussions --- p.61 / Chapter 3.3.1 --- Dye adsorbed TiO2 film stability --- p.61 / Chapter 3.3.2 --- Bactericidal activity of the dye-sensitized TiO2 films --- p.62 / Chapter 3.3.3 --- Bactericidal mechanism of the films under irradiation --- p.64 / Chapter CHAPTER FOUR: --- CONSLUSIONS --- p.68 / REFERENCES --- p.71

Mesoporous titania molecular-sieve thin films have been modified by incorporating guest species either in the pores or on the walls of the structure. The incorporation was realized with the aid of sonochemical processing. The structure, morphology, texture, optical properties, and stability of the resulting nanostructures were characterized by X-ray diffraction, nitrogen adsorption, UV-vis diffuse reflectance spectroscopy, infrared spectroscopy, photoluminesent spectroscopy, scanning electron microscopy, transmission electron microscopy, thermalgravimetric and differential thermal analyses. The photocatalytic and catalytic properties of the mesoporous TiO2-based nanocomposites were evaluated by photocatalytic degradation of organic pollutants, photo-assisted killing of bacteria/cancer-cells, and catalytic oxidation of carbon monoxide. / The thesis includes seven parts. The first part describes the pore-wall chemistry and photocatalytic activity of mesoporous nanocrystalline TiO 2 molecular sieve films. The ordered mesoporous TiO2 films show better photocatalytic activities than do the conventional sol-gel-derived TiO2 films toward the degradation of volatile organic pollutants. The reasons for the high activities of the mesostructural films are also discussed. The second part of the thesis reports the incorporation of highly dispersed gold nanoparticles in the mesoporous TiO2 films by a sono- and photochemical approach. The gold nanoparticles thus obtained are well-confined and stabilized in the nanopores of the TiO2 film and therefore, the intrinsic agglomeration of gold nanoparticles is prevented. This eliminates the use of potentially catalyst-poisoning organic ligands for stabilization. This method can also be used to prepare ordered mesoporous Pt/TiO2 and Ag/TiO2 nanocomposites with catalytic and photocatalytic functions as described in the third and forth parts of the thesis. In the fifth part, solid superacid molecular sieves are prepared by the wall-functionalization of the TiO2 film by sulfate groups with the aid of sonication. The resulting 3D-ordered mesoporous sulfated TiO2 superacid molecular sieve films are found to be attractive photocatalysts for environmental applications. The sixth part the thesis reported the sonodeposition of poorly dissolved phthalocyanine dyes onto the surface of the TiO2 film. The dye molecules are attached and stabilized in the pores of the film, avoiding the aggregation of the dye molecules, and consequently achieving effective photosensitization of the TiO2 film. The final part of the thesis describes the preparation of hierarchically macro/mesoporous TiO2 nanostructural photocatalysts. The existence of macroporous channels in a mesoporous TiO2 material improves the photoabsorption efficiency and matter-transfer. These enhance the photocatalytic performance of the bimodal porous TiO2 nanocomposites toward degradation organic pollutants in gas-phase. (Abstract shortened by UMI.) / Wang Xinchen. / "July 2005." / Adviser: Jimmy C. Yu. / Source: Dissertation Abstracts International, Volume: 67-01, Section: B, page: 0293. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / 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, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Thesis (M.S.)--Ohio University, June, 2003. / Title from PDF t.p. Includes bibliographical references (leaves 71-72).

Thesis (M.S.)--Ohio University, August, 1995. / Title from PDF t.p.

Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (leaves 106-116).

Cobalt doped anatase TiO2 films show room temperature ferromagnetism. Doping was provided by implantation using a MEVVA ion source. The enhancement of ferromagnetic properties was obtained by post-implantation annealing. The microstructure, magnetic properties and the dependence on the annealing conditions have being studied using various characterization techniques. Interestingly, the output referring to the saturation magnetization per Co atom with a value as high as 3.16 muB/Co atom, exceeds considerably that of the bulk cobalt which suggests that contribution to the overall magnetic behavior is not only a function of the concentration of inherently magnetic elements, but there must exist also sources of magnetisms. One of these sources are oxygen vacancies as discussed within this work. It is also interesting that instead of the more commonly observed hcp structure, the Co nanoclusters are found in fcc structure probably being stabilized by the TiO2 matrix. / In this work, we study the properties of cobalt-implanted titanium dioxide, a room temperature dilute ferromagnetic semiconductor discovered in 2001. The ferromagnetic interaction mechanism is however controversial. By using metal vapor vacuum arc (MEVVA) ion source, different doses of cobalt ions were implanted into anatase structures of titanium dioxide (TiO2) thin films. The TiO2 films which were sputtered on SiO2 (100nm)/Si (110) substrates and rutile structure of TiO2. The cobalt implanted TiO2 thin films were prepared with different atomic fraction and then thermally treated at different temperature after ion implantation. The structural properties of the anatase titanium dioxide were also studied as a comparison to rutile titanium dioxide. / Rutherford backscattering spectrometry (RBS) was performed to determine the composition of cobalt. The crystal structure of the thin films and rutile single crystal was mainly anatase as detected in XRD spectra. X-ray photoelectron spectrometry (XPS) and transmission electron microscopy (TEM) were also used in sample analysis. Vibrating sample magnetometer (VSM) was employed to study the magnetic properties of the cobalt implanted films. Ferromagnetic behaviors of these films were observed at room temperature. / Semiconductor spintronics is a promising new field of study in the ongoing quest to make electronic devices faster, cheaper, and more efficient. While current spintronics utilize the spin property of electrons to achieve greater functionally, the integration of spintronics into conventional semiconductor electronics will lead to advances optoelectronics, quantum computing, and other emerging fields of technology. This integration relies on effective generation; injection, transport, and detection of spin polarized electron current. To these end, mastering synthesis of room temperature ferromagnetic semiconductors is inevitable. / Luk, Wing Yan. / Adviser: H. P. Ho. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3730. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references. / 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, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 204-217).