¡@In this thesis, we have studied the growth of M-plane GaN thin film on LiGaO2 (100) substrate by Plasma-Assisted Molecular Beam Epitaxy. We found that the growth of GaN thin films on as-received LiGaO2 substrates is poly-crystalline by analysis of X-ray diffraction, and these of GaN thin films were peeled off after thin film process. Using atomic force microscopy (AFM) to scan the surface of as-received LiGaO2 substrate, we found that many particles which are Ga2O3 existed on the surface of as-received LiGaO2. The annealing ambient for LiGaO2 substrates in vacuum and air ambient has been studied in order to improve the surface of LiGaO2. The scanning results of AFM shows that the crystal quality and stress of M-plane GaN grown on LiGaO2 (100) substrate pre-annealed in air ambient is significantly improved. We conclude that the reason of GaN peeling off from LiGaO2 substrate is attributed to stress between GaN/ LiGaO2. The measurement of polarization-dependent PL shows that the luminescence intensity of growing sample increases and reaches a maximum at £p = 90¢X (E¡æc), which indicates the growing samples is M-plane GaN as well. The microstructure of growing samples was characterized by transmission electron microscopy. We found that the formation of stacking fault in GaN is attributed to the growth of GaN on cubic-Ga2O3 nano-particles. The formation of Ga2O3 nano-particles can be suppressed by pre-annealing LiGaO2 substrate in air. It revealed that the thermal annealing LiGaO2 substrate in air ambient can improve the surface of LiGaO2 substrate effectively, and then one can grow a high quality M-plane GaN thin film on the LiGaO2 substrate.

In this thesis, we fabricate the quantum dots (QDs) micro-pillar of metal-coated by E-beam lithography, and analyze the optical and electrical properties of micro-pillar cavity devices. For the sample materials, we use S-K mode to grow 3-layer In0.75Ga0.25As QDs structures sandwiched by up and down Al0.5Ga0.5As cladding layer on GaAs substrate by molecular-beam epitaxy (MBE). 40nm GaAs spacer layers with 2nm p-modulation doping in the central barrier are adopted in this study. The micro-pillar with diameter of 2 m, metal coated on top (p-type) and down (n-type) facet are designed. The good reflectivities of metal contacts provide more energy extraction inside the cavity. We expect the device lasing while the current injection. First, we design the morphology and size of patterns by AutoCAD software. Then, we use e-beam lithography with proper exposure condition to define the patterns, and thermal evaporation to deposit metals. The superfluous metal is lifted off and the defined area metal is served as dry etching mask to transfer the pattern to the dielectric layer and epi-layer. Finally, we use SiO2 layer to prevent current leakage, and the p-n contact on each facet to complete the devices. Micro-pillar samples with/without metal coated are analyzed by micro-PL system. The emission wavelength of 1282nm and the calculated Q-value of 100 are obtained for the sample with metal coated, an increase of 500%. From the EL measurement results, the device of micro-pillar samples with metal coated generate three peaks, 1149nm, 1221nm and 1291nm. Besides, it can efficiently improve the emission intensities. The measured result matched the simulation result.

Abstract Negative index structures could be implemented through surface Plasmon polariton waves generated by nanostructures. We are interested in PMMA grating structure on curved metal surface. In order to fabricate this kind of samples, a series process parameters have been tested and also the lift-off process has been developed. Our results show superlens effect under optical microscope(OM). The sub-wavelength grating image is reconstructed in the non-grating region where the PMMA dielectric layer is not uniform. Surface Plasmon(SPP) waves generated in the grating region propagate to the non-grating region and are scattered out through the non-uniform PMMA layer. The grating information is not resolvable under OM but clear in the reconstructed region. It shows that SPP waves can show super resolution and a simple batch process should be developed in the future.

New measuring methods continue to be developed in the field of wind anemometry for various environments subject to low-speed and high-speed flows, turbulent-present flows, and ideal and non-ideal flows. As a result, anemometry has taken different avenues for these environments from the traditional cup model to sonar, hot-wire, and recent developments with sphere anemometers. Several measurement methods have modeled the air drag force as a quadratic function of the corresponding wind speed. Furthermore, by incorporating non-drag fluid forces in addition to the main drag force, a dynamic set of equations of motion for the deflection and strain of a spherical anemometer's beam can be derived. By utilizing the equations of motion to develop a direct relationship to a measurable parameter, such as strain, an approximation for wind speed based on a measurement is available. These ODE's for the strain model can then be used to relate directly the fluid speed (wind) to the strain along the beam’s length. The spherical anemometer introduced by the German researcher Holling presents the opportunity to incorporate the theoretical cantilevered Euler-Bernoulli beam with a spherical mass tip to develop a deflection and wind relationship driven by cross-area of the spherical mass and constriction of the shaft or the beam's bending properties. The application of Hamilton's principle and separation of variables to the Lagrangian Mechanics of an Euler-Bernoulli beam results in the equations of motion for the deflection of the beam as a second order partial differential equation (PDE). The boundary conditions of our beam's motion are influenced by the applied fluid forces of a relative drag force and the added mass and buoyancy of the sphere. Strain gauges will provide measurements in a practical but non-intrusive method and thus the concept of a measuring strain gauge is simulated. Young's Modulus creates a relationship between deflection and strain of an Euler-Bernoulli system and thus a strain and wind relation can be modeled as an ODE. This theoretical sphere anemometer's second order ODE allows for analysis of the linear and non-linear accuracies of the motion of this dynamic system at conventional high speed conditions.

Aluminum nitride (AlN) thin film is a promising material as buffer layer in GaN-based optoelectronic and electronic devices or as a substrate to fabricate Surface Acoustic Wave (SAW) and Film Bulk Acoustic wave Resonant (FBAR) devices in high frequency in wireless (>1GHz) communication technology. Aluminum nitride, thin film with the c-axis normal to the film is favored in a low energy deposition condition because it places the packed hexagonal basal plane parallel to the substrate surface. Grains of this orientation have a low surface energy which favors rapid growth in a columnar structure. In this experiment r.f. dual ion beam sputtering (DIBS) system is used to prepare the AlN films on Si (100) substrate. Various processing variable were tested to deposit AlN films with desirable properties. After systematic testing, a high quality film with preferred c-axis orientation was grown successfully on Si (100) substrate with Al target under the process parameters of 700 ev energy flux; 55% N2 / (N2+Ar) ratio; 4X10 - 4 torr working pressure with no heating of substrate. The AlN target is also used. The results show the great sensitivity of the films to oxygen-containing environments. Only under low residual oxygen pressure, could aluminum nitride be grown well. The deposited AlN thin film characteristic were studied by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM), Secondary Ion Mass Spectrometry (SIMS) and Electron Spectroscopy for Chemical Analysis (ESCA).

Ti nano-films are deposited on a NaCl(001) single crystal substrate by ion beam sputtering from a Ti target, and then annealed. Ti crystallites on a NaCl(001) substrate with increase in the substrate temperature and annealing have the preferred orientation (1-101) and (0001).

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Nanocrystalline £\-Zr condensates deposited by ion beam sputtering on the NaCl (100) surfaces and then annealed at 100 ¢J to 750 ¢J in air. The phases present were identified by transmission electron microscopy to be nanometer-size £\-Zr+ZrO¡B£\-Zr+ZrO+c-ZrO2¡Bc-ZrO2¡Bc-+t-ZrO2¡Bt-ZrO2¡Band t-+m-ZrO2 phase assemblages with increasing annealing temperature. The zirconia showed strong {100} preferred orientation due to parallel epitaxy with NaCl (100) when annealed between 150 ¢J and 500 ¢J in air. The c- and t-zirconia condensates also showed (111)-specific coalescence among themselves. The c- and/or t-ZrO2 formation can be accounted for by the small grain size, the presence of low-valence Zr cation and the lateral constraint of the neighboring grains. (Part 1) Nanocrystalline £\-Zr condensates were deposited on the NaCl (100) plane at 25 to 450 ¢J by radio frequency ion beam sputtering from a pure 99.9¢H Zr disk. The nano condensates were identified by transmission electron microscopy to be quasiamorphous, £\-Zr, £\-Zr+ZrO and £\-Zr+ZrO+c-ZrO2 phase assemblages with increasing substrate temperature. At 400 ¢J and under 1-20 sccm oxygen, c- and t-ZrO2 nanocondensates were assembled on NaCl (100) as monolayer nanocrystalline material and showed strong preferred orientation. The c- and/or t-ZrO2 were retained by small grain size, low-valence Zr cation and 2-D matrix constraint of the film. (Part 2) Nanosized c- and t-ZrO2 were formed as monolayer nanocrystalline film on NaCl (100) plane by radio frequency ion beam sputtering. The microstructure and the epitaxy relationship with the NaCl (100) plane were studied by a high resolution transmission electron microscope. The epitaxy orientation was found to be [001]Z//[001]N, [100]Z//[1 0]N (group A), and [011]Z//[001]N, [100]Z//[100]N (group B) between zirconia (Z) and NaCl (N). Group B has two variants and is the dominant type. The possible causes for the epitaxy relationship are discussed. Crystallites within the same group can merge by rotation and coalesce into a single crystal, whereas crystallites in different groups can form high-angle grain boundaries. (Part 3) Special interfaces were formed for the c- and/or t-ZrO2 (Z) nano-crystals when deposited on the NaCl (N) (100) cleavage plane by ion beam sputtering to follow the epitaxy relationships of [001]Z//[001]N, (100)Z//(1 0)N (group A); and [011]Z//[001]N, (100)Z//(100)N (group B1) or (100)Z//(010)N (group B2). The nanoparticles in group A and B were impinged and coalesced to form {220}A/{200}B and {200}A/{111}B interfaces; with anchored dislocation whereas those in group B1 and B2 form {220}B1/{200}B2 interface. The {220}A/{200}B interface is found to be of especially low energy due to good match O2¡V lattice sites, and smoothly joints {200} and {220} planes across the interfaces without mismatch strain and dislocations. The special interfaces may shed light on the epitaxial mechanism of nanocrystalline materials in general. (Part 4)

Due to the property of the photonic crystal, like bandgap, many researches on them are discussed. Photons with wavelength within the bandgap cannot propagate through the crystal. Then placing some defects in the crystal, because the periodic arrangement is destroyed, it is possible to build a waveguide to guide light along certain path. One kind is coupled cavity waveguide. The photons can propagate in a coupled-cavity waveguide by coupling without radiation losses. So it is widely used to implement a variety of optical devices. In this thesis, we use coupled cavity waveguide to construct devices. And the characteristics of Mach-Zehnder interferometer and power splitter are discussed. Then we propose two logic gate structures with an input port and two control ports. The state of control port determines the electric field at the output port. Besides, the four-port channel drop filter is proposed. It will make the three wavelengths ¢w1310, 1490 and 1550 nm¢w propagate in different waveguides. So it could be used as a wavelength demultiplexer for FTTH. Finally, the property of the PC-based rat-race circuit is investigated. By adjusting the phase of the control signal, we could decide the input signal to exit from output 1 or output 2. In this way, we could use it to function as a switch.

In this thesis the methods of optical beam induced current (OBIC), multi-photon excitation, and confocal microscopy were employed to study InGaN LED¡¦s. Recently, important breakthrough and achievement have been made in the developments of InGaN based opto-electronic components. As a result, it is important to characterize the properties and the performance of InGaN based devices with various techniques. In this thesis, we have used 2-photon OBIC microscopy to observe various such LED¡¦s. We found that the LED¡¦s exhibit dotted pattern which can not be seen under 1-photon excitation. In addition, we have employed micro-spectroscopy to characterize the active layer of these LED¡¦s. These results will be discussed in this thesis in detail.