Thesis (M.Phil.)--Chinese University of Hong Kong. / Includes bibliographies.

Chan Siu-pang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 45-47). / Abstract also in Chinese. / TITLE PAGE --- p.i / THESIS COMMUTE --- p.ii / ABSTRACT (English) --- p.iii / ABSTRACT (Chinese) --- p.iv / ACKNOWLEDGMENT --- p.v / TABLE OF CONTENTS --- p.vi / LIST OF FIGURES --- p.vii / LIST OF TABLES --- p.viii / Chapter CHAPTER 1. --- Introduction --- p.1 / Chapter Section 1.1. --- General Introduction --- p.1 / Chapter Section 1.2. --- Background Information --- p.2 / Chapter 1.2.1. --- Si(100) Surface --- p.2 / Chapter 1.2.2. --- Structure of Cl/Si(100) --- p.7 / Chapter Section 1.3. --- Etching of Si(100) by Chlorine --- p.9 / Chapter Section 1.4. --- Theory --- p.14 / Chapter Section 1.5. --- Computational Model --- p.17 / Chapter CHAPTER 2. --- Desorption Mechanism of SiCl4 --- p.19 / Chapter Section 2.1. --- Desorption Mechanism --- p.19 / Chapter 2.1.1. --- Trajectory1 --- p.20 / Chapter 2.1.2. --- Trajectory2 --- p.23 / Chapter 2.1.3. --- Trajectory3 --- p.26 / Chapter 2.1.4. --- Trajectory4 --- p.29 / Chapter 2.1.5. --- Trajectory5 --- p.32 / Chapter 2.1.6. --- Trajectory6 --- p.35 / Chapter Section 2.2. --- Discussion --- p.38 / Chapter Section 2.3. --- Conclusion --- p.44 / REFERENCES: --- p.45

by Chung Pui Shan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 105-110). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.iii / Table of contents --- p.v / Chapter Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Metal clusters embedded in fused silica glass --- p.2 / Chapter 1.2 --- Ion implantation of metal clusters --- p.3 / Chapter 1.3 --- Feature of MEVVA implantation --- p.5 / Chapter 1.4 --- Motivation and organization of this thesis --- p.7 / Chapter Chapter 2. --- Sample Preparation and Characterization Methods / Chapter 2.1 --- MEVVA implantation --- p.9 / Chapter 2.2 --- TRIM simulation --- p.11 / Chapter 2.3 --- Sample preparation --- p.14 / Chapter 2.4 --- Rutherford backscattering spectroscopy (RBS) --- p.16 / Chapter 2.5 --- X-ray diffraction (XRD) technique --- p.17 / Chapter 2.6 --- X-ray photoelectron spectroscopy (XPS) --- p.21 / Chapter 2.7 --- Transmission electron microscopy (TEM) technique --- p.24 / Chapter 2.8 --- Spectroscopic ellipsometry (S.E.) --- p.25 / Chapter 2.9 --- Z-scan technique --- p.32 / Chapter Chapter 3. --- Characterization of Single Implanted Samples / Chapter 3.1 --- Experimental results and discussion / Chapter 3.1.1 --- RBS --- p.35 / Chapter 3.1.2 --- XRD --- p.38 / Chapter 3.1.3 --- XPS --- p.42 / Chapter 3.1.4 --- XTEM --- p.49 / Chapter 3.1.5 --- S.E --- p.54 / Chapter 3.1.6 --- Z-scan measurements --- p.60 / Chapter 3.2 --- Summary --- p.65 / Chapter Chapter 4. --- Characterization of Sequentially Cu-Ni Implanted Samples / Chapter 4.1 --- Experimental results and discussion / Chapter 4.1.1 --- XRD --- p.66 / Chapter 4.1.2 --- XPS --- p.68 / Chapter 4.1.3 --- XTEM --- p.77 / Chapter 4.1.4 --- Z-scan measurements --- p.87 / Chapter 4.2 --- Summary --- p.91 / Chapter Chapter 5. --- Conclusion and Future Works / Chapter 5.1 --- Conclusion --- p.92 / Chapter 5.2 --- Future works --- p.93 / Appendix / Appendix I --- p.94 / Chapter ☆ --- Sample preparation procedures for XTEM / Appendix II --- p.97 / Chapter ☆ --- Alignment procedures of S.E. / Chapter ☆ --- Implementation of the Merlin system / Appendix III --- p.101 / Chapter ☆ --- Calibration of S.E. / Reference --- p.105

Chong Yuen Tung = 硅化鐵薄膜的相和微觀結構 / 莊宛曈. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 63-65). / Text in English; abstracts in English and Chinese. / Chong Yuen Tung = Gui hua tie bo mo de xiang he wei guan jie gou / Zhuang Wantong. / Abstract --- p.i / 摘要 --- p.ii / Acknowledgment --- p.iii / Table of contents --- p.iv / List of Figures --- p.viii / List of Tables --- p.x / Chapter CHAPTER 1: --- Introduction --- p.1 / Chapter CHAPTER 2: --- Background --- p.4 / Chapter 2.1 --- Phases of crystalline FeSi2 --- p.4 / Chapter 2.2 --- Electronic structure of β-FeSi2 --- p.7 / Chapter 2.3 --- Orientation relationship between β-FeSi2 and Si --- p.8 / Chapter CHAPTER 3: --- Instrumentation --- p.10 / Chapter 3.1 --- Metal vapor vacuum arc ion source implantation --- p.10 / Chapter 3.2 --- Rutherford backscattering --- p.12 / Chapter 3.3 --- Transmission Electron Microscopy (TEM) --- p.13 / Chapter 3.3.1 --- Principles of TEM --- p.13 / Chapter 3.3.2 --- Electron specimen interaction and contrast --- p.14 / Chapter 3.3.3 --- Electron Diffraction --- p.15 / Chapter 3.3.4 --- Sample Preparation --- p.17 / Chapter 3.3.4.1 --- Plan-view sample --- p.17 / Chapter 3.3.4.2 --- Cross-section sample --- p.17 / Chapter CHAPTER 4: --- FeSi2 films fabricated by ion implantation --- p.18 / Chapter 4.1 --- Introduction --- p.18 / Chapter 4.2 --- Experimental details --- p.18 / Chapter 4.3 --- Ion energy series --- p.19 / Chapter 4.3.1 --- As-implanted sample --- p.19 / Chapter 4.3.1.1 --- Results --- p.20 / Chapter 4.3.1.2 --- Discussions --- p.20 / Chapter 4.3.2 --- Annealed samples --- p.24 / Chapter 4.3.2.1 --- Morphology of the annealed samples and the damage on Si substrate --- p.24 / Chapter 4.3.2.2 --- Identification of the FeSi2 phase and their orientation relationship with the Si matrix --- p.24 / Chapter 4.3.2.3 --- Photoluminescence of the samples --- p.26 / Chapter 4.3.2.4 --- Discussions --- p.26 / Chapter 4.4 --- Ion dosage series --- p.31 / Chapter 4.4.1 --- Results --- p.31 / Chapter 4.4.2 --- Discussions --- p.32 / Chapter 4.5 --- Summary --- p.36 / Chapter CHAPTER 5: --- Effect of post annealing on the phase and microstructure of FeSi2 --- p.37 / Chapter 5.1 --- Introduction --- p.37 / Chapter 5.2 --- Experimental details --- p.37 / Chapter 5.3 --- The correlation between microstructure of FeSi2 synthesized under different annealing conditions and their PL --- p.38 / Chapter 5.3.1 --- RTA series --- p.38 / Chapter 5.3.1.1 --- Results --- p.38 / Chapter 5.3.1.2 --- Discussions --- p.39 / Chapter 5.3.2 --- FA series --- p.42 / Chapter 5.3.2.1 --- Results --- p.42 / Chapter 5.3.2.2 --- Discussions --- p.44 / Chapter 5.3.3 --- RTAFA series --- p.45 / Chapter 5.3.3.1 --- Results --- p.45 / Chapter 5.3.3.2 --- Discussions --- p.45 / Chapter 5.4 --- The existence of alpha phase and its special shape --- p.51 / Chapter 5.4.1 --- Results --- p.51 / Chapter 5.4.2 --- Discussions --- p.52 / Chapter 5.5 --- The existence of gamma phase in 1050°C furnace annealed sample / Chapter 5.5.1 --- Results --- p.56 / Chapter 5.5.2 --- Discussions --- p.57 / Chapter 5.6 --- Summary --- p.59 / Chapter CHAPTER 6: --- Conclusions --- p.61 / References --- p.63

Photonic crystals (PhCs) are periodically structured electromagnetic media, generally characterised by not permitting light of defined ranges of frequency to propagate through the structure. These disallowed ranges of frequency are known as photonic band gaps. The intentional introduction of defects into the crystal gives rise to localized electromagnetic states that provide a mechanism for the control of the propagation of photons through PhCs. In the case of one dimensional (1-D) PhCs, the introduction of a single defect into a finite PhC results in the formation of a resonant cavity structure, a so-called microcavity. The ease of fabrication and scope for integration make 1-D PhCs good candidates for the future applications of PhCs in light transmission systems and, as such, these structures are the focus of the research reported here. The aim of this thesis is to report a practical study of passive 1-D PhC devices and thereby extend the base of measurements that support and extend the results of theory and simulation. Various types of 1-D PhC structures have been fabricated using electron beam lithography and inductively coupled plasma technologies in a clean-room environment. The fabricated structures in effect demonstrate a first or primitive level of integration of 1-D PhCs with another optical device, namely a ridge waveguide. Measurements were performed by butt-coupling from a single mode fibre taper of the transmission characteristics of the resulting integrated waveguides, whilst a Side-band measurement method for very high resolution (0.2pm) microcavity characterisation was invented during the measurement process. A multiple wavelength transmission optical filter transmitting at the telecommunication wavelengths of 1310nm and 1550nm, and which could be used in a WDM system was demonstrated. The effect of introducing mode matching structures to minimize II the scattering loss and boost the quality factor value was investigated. Optimum positioning of the tapers produced a significant enhancement of Q. Finally, a narrow pass band filter constructed from coupled cavities was fabricated and characterised. A quasi-flat transmission peak with a pass band width of just 4nm was observed.

Self-assembly of nanomaterials over macroscopic dimensions and development of novel nano-electromechanical systems (NEMS) hold great promise for numerous nanotech applications. However, it has always been a great challenge to find a general route for controlled self-assembly of nanomaterials and generating electromechanical response at the nanoscale level. This work indicates that self-organized anisotropic nematic liquid crystals (LC) can be exploited for nanotemplating purposes to pattern carbon nanotubes (CNTs) and Quantum dots (QDs) over a macroscopic dimension. The pattern formed by the CNTs or QDs can be controlled by applying external electric and magnetic fields, developing novel nano-electromechanical and nano-magnetomechanical systems. Self-organizing nematic liquid crystals (LC) impart their orientational order onto dispersed carbon nanotubes (CNTs) and obtain CNT-self-assembly on a macroscopic dimension. The nanotubes-long axis, being coupled to the nematic director, enables orientational manipulation via the LC nematic reorientation. Electric field induced director rotation of a nematic LC+CNT system is of potential interest due to its possible application as a nano-electromechanical system. Electric field and temperature dependence of dielectric properties of an LC+CNT composite system have been investigated to understand the principles governing CNT-assembly mediated by the LC. In the LC+CNT nematic phase, the dielectric relaxation on removing the applied field follows a single exponential decay, exhibiting a faster decay response than the pure LC above a threshold field. Due to a strong LC-CNT anchoring energy and structural symmetry matching, CNT long axis follows the director field, possessing enhanced dielectric anisotropy of the LC media. This strong anchoring energy stabilizes local pseudo-nematic domains, resulting in nonzero dielectric anisotropy in the isotropic LC phase. These anisotropic domains respond to external electric fields and show intrinsic frequency response. The presence of these domains makes the isotropic phase electric field-responsive, giving rise to a large dielectric hysteresis effect. These polarized domains maintain local directors, and do not relax back to the original state on switching the field off, showing non-volatile electromechanical memory effect. Assembling quantum dots (QDs) into nanoscale configurations over macroscopic dimensions is an important goal to realizing their electro-optical potential. In this work, we present a detailed study of a pentylcyanobiphenyl liquid crystal (LC) and a CdS QD colloidal dispersion by probing the dielectric property  and relaxation as a function of an applied ac-electric field Eac. In principle, dispersing QDs in a nematic LC medium can direct the dots to align in nearly one-dimensional chain-like structures along the nematic director and these assemblies of QDs can be directed by external electric fields. In a uniform planar aligned cell, the Fréedericksz switching of the LC+QDs appears as a two-step process with the same initial switching field as the bulk but with the final value larger than that for an aligned bulk LC. The relaxation of  immediately following the removal of Eac follows a single-exponential decay to its original value that is slower than the bulk but becomes progressively faster with increasing Eac, eventually saturating. These results suggest that the arrangement of the QDs is mediated by the LC.

Topological photonics/phononics, inspired by the discovery of topological insulators, is a prosperous field of research, in which remarkable one-way propagation edge states are robust against impurities or defect without backscattering. This dissertation discusses the implementation of multiple topological phases in specific designed photonic and phononic crystals. First, it reports a tunable quantum Hall phase in acoustic ring-waveguide system. A new three-band model focused on the topological transitions at the Γ point is studied, which gives the functionality that nontrivial topology can be tuned by changing the strengths of the couplings and/or the broken time-reversal symmetry. The resulted tunable topological edge states are also numerically verified. Second, based on our previous studied acoustic ring-waveguide system, we introduce anisotropy by tuning the couplings along different directions. We find that the bandgap topology is related to the frequency and directions. We report our proposal on a frequency filter designed from such an anisotropic topological phononic crystal. Third, motivated by the recent progress on quantum spin Hall phases, we propose a design of time-reversal symmetry broken quantum spin Hall insulators in photonics, in which a new quantum anomalous Hall phase emerges. It supports a chiral edge state with certain spin orientations, which is robust against the magnetic impurities. We also report the realization of the quantum anomalous Hall phase in phononics.

From the alignment of magnets to the melting of ice, the transition between different phases of matter underpins our exploitation of materials. Both a quantum and a classical phase can undergo an instability into another state. In this thesis, we study the stability of matter in both contexts: topological states and crystalline solids. We start with the stability of fractional quantum Hall states on a lattice, known as fractional Chern insulators. We investigate, using exact diagonalization, fractional Chern insulators in higher Chern bands of the Harper-Hofstadter model, and examine the robustness of their many-body energy gap in the effective continuum limit. We report evidence of stable states in this regime; comment on two cases associated with a bosonic integer quantum Hall effect; and find a modulation of the correlation function in higher Chern bands. We next examine the stability of molecules using variational and diffusion Monte Carlo. By incorporating the matrix of force constants directly into the algorithms, we find that we are able to improve the efficiency and accuracy of atomic relaxation and eigenfrequency calculation. We test the performance on a diverse selection of case studies, with varying symmetries and mass distributions, and show that the proposed formalism outperforms existing restricted Hartree-Fock and density functional theory methods. Finally, we analyze the stability of three-dimensional crystals. We note that for repulsive Coulomb crystals of point nuclei, cubic systems have a zero matrix of force constants at second order. We investigate this by constructing an analytical model in the tight-binding approximation, and present a phase diagram of the most stable crystal structures, as we tune core and valence orbital radii. We reconcile our results with calculations in the nearly free electron regime, as well as current research in condensed matter and plasma physics.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Vita. / Includes bibliographical references. / by James David Hodge. / Ph.D.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE / Includes bibliographical references. / by Gretchen Lynn Kalonji. / Ph.D.