Dissertations / Theses on the topic 'Thin film analysis'

A combined approach to the use of surface analysis techniques and X-ray diffraction has been introduced. In particular the development of the microstructure of UHV evaporated thin metallic films has been investigated with a view to clarifying influences on microstructure (particularly texture). This study has shown the wide range of experimental parameters which affect the final film structure, such as temperature, oblique incidence and substrate roughness. An automated energy dispersive X-ray diffractometer has been developed for the study of thin film texture. The required corrections for loss of intensity due to sample positioning have been developed and verified. Pole figures have been collected for erbium and nickel thin films (thickness 200-1200 nm) grown on molybdenum or glass substrates. Results for the erbium films show a substantial effect on the texture of the film, contributed by the temperature of the substrate during deposition. The texture varies from mixed fiber at low temperature, to a strong single fiber orientation at around 663 K, to mixed fiber at higher temperatures. The strong orientation at 663 K has been shown to vary from either (002) to (101) depending on as yet unknown experimental conditions. The effect of substrate roughness appears to be only in the degree of orientation and it does not affect the overall nature of the texture of the film. The texture of the nickel films shows a form of "granular epitaxy" at substrate temperatures above 300 K. The presence of tensile stress within one of these nickel thin film samples has been determined and is interpreted to give support to a proposed mode of granular epitaxy.

A phase-conjugate interferometric method of thin film analysis obtains three independent parameters with which to determine a film's refractive index n, absorption coefficient kappa, and thickness d. Because dimensionless intensity ratios are used, this method is self-calibrating except for light source polarization and incident angle. The use of self-pumped phase-conjugate reflectors makes the interferometer self-aligning and results in infinite spacing of fringes of equal thickness. A single layer thin film sample was analyzed by this technique, and the results compared to those of ellipsometry.

This thesis is intended to fulfill the requirements of the Math and Physics departments at Harvey Mudd College. We begin with a brief introduction to the study of surfactant dynamics followed by some background on the experimental framework our work is related to. We then go through a derivation of the model we use, and explore in depth the nature of the Equation of State (EoS), the relationship between the surface tension on a fluid and the surfactant concentration. We consider the effect of using an empirical equation of state on the results of the simulations and compare the new results against the results produced using a multilayer (EoS) as well as experimental observations. We find that the empirical EoS leads to two new behaviors - preserving of large gradients of surfactant concentration and the occurrence of dynamics in distinct regimes. These behaviors suggest that the empirical EoS improves the agreement of the model’s prediction with experiment.

Hard ceramic films of micrometric thickness deposited on a soft metallic substrate have ushered in a new era in the fabrication of structural, tribological, microelectronic and optical components. The mechanical performance of these components is however critically dependent on the strength and toughness of these films as well as on those of the film-substrate interface. Recent studies have shown that cylindrical and radial cracks can propagate through the film during nanoindentation tests with spherically tipped and pointed indenters, resulting in steps in the load versus displacement curve. In this thesis, the mechanics of fracture of thin hard films bonded to soft substrates, during nanoindentation is studied by carrying out finite element analyses. The role of plastic yielding in the substrate on the above issue is examined. Another important objective of this work is to propose a method by which finite element simulations can be employed to interpret nanoindentation test results and yield information related to the fracture behaviour of hard films. To this end, axisymmetric finite element analyses of spherical nanoindentation of a TiN film of thickness t = 1 //m, on a steel substrate are carried out. Numerical algorithms for large deformation, contact simulation and computation of energy release rate are employed in the analyses. The film is assumed to be linear elastic, whereas, an elastic-plastic constitutive model is used for the substrate. A nanoindentation analysis of the uncracked film is first carried out. The development of plastic yielding in the substrate and its influence on the load P versus penetration h characteristics is examined. The stress fields around the indenter for different depths of indentation are studied. The results show that the radial stress attains a tensile peak at the film surface, just outside the indented zone. However, it becomes compressive with increasing distance below the surface. Interestingly, a tensile radial stress prevails at the film-substrate interface at large indentation depth. The shear stress increases to a peak value at a distance of 0.052 to OAt below the film surface depending upon the radial location and then reduces. Next, circumferential cracks extending downwards from the film surface are introduced at different radial distances R from the axis of symmetry. Finite element analyses are carried out till the indented zone extends almost up to the crack surface. The energy release rate J is computed as a function of indentation depth for different crack lengths c (in the range from O.lt to 0.9t). The results show that shallow cracks are essentially under Mode II loading with closure of crack faces caused by compressive radial stresses. However, a mixed-mode state prevails if the crack length is large (c > 0.62), with crack faces opening out due to tensile radial stress near the film-substrate interface. The variation of J with c/t for cracks located at different radial distances R is examined. It is found that for small R, there is a decreasing branch in the J versus c variation between c = 0.2i to 0.75£ which indicates that crack extension in this range will be stable. On the other hand, for large R, J increases monotonically with c/t which implies that unstable fracture of the full film thickness will occur following crack initiation. A composite nomogram is generated in the P — h plane where constant J lines are plotted along with load-displacement curves for different crack lengths. If now a nanoindentation (experimental) load-displacement behaviour is superimposed on this nomogram, the initial crack length (of a pre-existing flaw), the final crack length and fracture energy of the film can be inferred. In the last part of the thesis, the effect of the substrate yield strength on the indentation mechanics is studied. It is found that upon decreasing the yield strength, the load at a given indentation depth decreases while the residual depth at unloading increases. Also, the energy release rate for a given radial location and crack length reduces considerably at large depths of indentation.

Lab-on-a-chip devices, also known as micro total analysis systems (μTAS), are implementations of chemical analysis systems on microchips. These systems can be fabricated using standard thin film processing techniques. Microfluidic and nanofluidic channels are fabricated in this work through sacrificial etching. Microchannels are fabricated utilizing cores made from AZ3330 and SU8 photoresist. Multi-channel electroosmotic (EO) pumps are evaluated and the accompanying channel zeta potentials are calculated. Capillary flow is studied as an effective filling mechanism for nanochannels. Experimental departure from the Washburn model is considered, where capillary flow rates lie within 10% to 70% of theoretical values. Nanochannels are fabricated utilizing cores made from aluminum, germanium, and chromium. Nanochannels are made with 5 μm thick top layers of oxide to prevent dynamic channel deformation. Nanochannel separation schemes are considered, including Ogston sieving, entropic trapping, reptation, electrostatic sieving, and immutable trapping. Immutable trapping is studied through dual-segment nanochannels that capture analytes that are too large to pass from one channel into a second, smaller channel. Polymer nanoparticles, Herpes simplex virus type 1 capsids, and hepatitis B virus capsids are trapped and detected. The signal-to-noise ratio of the fluorescently-detected signal is shown to be greater than 3 for all analyte concentrations considered.

EDS is a tool for quantitative and qualitative analysis of the materials. In electron microscopy, the energy of the electrons determines the depth of the region where the X-rays come from. By varying the energy of the electrons, the depth of the region where the X-rays come from can be changed. If a thin film is used as a specimen, different quantitative ratios of the elements for different electron energies can be obtained. Unique thickness of a specific film on a specific substrate gives unique energy-ratio diagram so the thickness of a thin film can be calculated by analyzing the fingerprints of the energy-ratio diagram of the EDS data obtained from the film.

Novel applications for calix[4]recorcinarene (C[4]RA) sensing membranes have been investigated. A comprehensive deposition study was carried out, encompassing casting, spin coating and Langmuir Blodgett (LB) deposition. The spin coating thickness depended on the angular velocity w, following the description of d = c.wx with coefficients of x - 0.44 and - 0.48 for concentrations of 1 mg/ml and 2mg/ml respectively. The analysis of the LB deposited films established a thickness of 0.95 nm for a monolayer. Furthermore the C[4]RA, was successfully employed as a deposition matrix for a non surface active polymer, poly-ortho-methoxy aniline (POMA), which can otherwise not be deposited by LB. The composite film showed good homogeneity and based on thickness and UV measurements a structural model for it was developed, in which two polymer strands aligned themselves per C[4]RA layer, resulting in a monolayer thickness of 2.1 - 2.2 nm. The response of the C[4]RA and the composite membranes to a variety of organic and inorganic gaseous pollutants was investigated by Surface Plasmon Resonance studies, conductivity and capacitance measurements and UV spectroscopic studies. The integration of cast films into the gate of a charge flow transistor, is the first application of pure calixarenes in a conduction based sensor. The turn on response of the transistor is modulated by a variety of organic vapours, at the saturation vapour pressure, showing selectivity between polar and non-polar solvents, i.e. chloroform, methanol, acetone and hexane, with no cross sensitivity to water vapour. The modulation lies within factors of 45 for CHCI3 and 13 for CH3OH. The conductivity increase is partially attributed to micro-condensation of the vapours inside the micro-porous membrane. A successful application of this implementation as an explosion guard sensor for acetone is demonstrated. Gold electrodes with and without C[4]RA LB films have been characterised using impedance spectroscopy and cyclic voltammography. The modification of the gold electrodes by the C[4]RA film changes their constant phase element impedance, given by 1/(w.Q)" with w being the angular velocity. The observed values were from Q =0.725-10 -5 Farad and n = 0.87 to Q = 0.828-10-6 Farad and n = 0.82. Organic analyteslike, chloroform and acetone in water can be successfully detected with these electrodes. It is shown by cyclic voltammetry, that the permeability of the C[4]RA LB films is modulated by the organic solvents.

To cope with energy requirements the utilization of renewable energies, particularly the Sun supplies the biggest and abundant energy source in Earth. Photo-voltaic and solar cell are the well advance and burning technology and a field of hot research. Majority of research centers and universities are working in this field. 1G, 2G, 3G and next generation of photo-voltaic cells have been developed and still to improve its efficiency and to decrease it 0.2 $/W cost. Our work mainly based on the theoretical and physical analysis of thin-film Photovoltaic devices. We will explore different software used for the analysis of PV cells, and will analyse different simulation related to solar cells like open circuit voltage VOC, Short circuit current JSC, Fill Factor FF (%) and external Quantum efficiency (%) for thin film solar cell including CIGS, CIS, CGS, CdTe, SnS/CdS/ZnO etc. To have different analysis for different combination and different replacement for materials used in the solar cell fabrication. To cope with the PV cost and environmental hazards we have to find alternate solutions.<br>Ullah, H. (2015). Simulation studies of photovoltaic thin film devices [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48800<br>TESIS

[ES] Desde hace una década se esta investigando intensamente la forma de mejorar la eficiencia de conversión de energía (PCE) de las células solares de silicio (Si) y reducir sus precios. Sin embargo, a pesar de las mejoras obtenidas, la fabricación de células solares de Si sigue siendo costosa y puede rebajarse usando materiales en forma de capa fina. Por ello la búsqueda de materiales absorbentes alternativos, no tóxicos, abundantes en la naturaleza y con buenos rendimientos de conversión se ha intensificado en los últimos años. Entre los diferentes materiales absorbentes el sulfuro de estaño (SnS), con una banda prohibida de 1.3 eV cercana a la óptima, es un candidato adecuado para la conversión fotovoltaica. Pero para células experimentales de SnS el rendimiento alcanzado hasta ahora es de 4.6%, que es mucho menos que el PCE para dispositivos de silicio, mientras que entre otras células híbridas (orgánicas-no orgánicas) como la perovskita de metilamonio de plomo y yodo (MAPbI3) se demuestra que es un candidato adecuado con PCE que alcanza un valor del 23%. Aparte de la estabilidad, uno de los problemas para la comercialización de células de MAPbI3 es la naturaleza tóxica del plomo (Pb). Por este motivo, se ha utilizado el análisis numérico para revisar los parámetros de diseño de las células solares de perovskita híbrida sustituyendo el absorbente MAPbI3 por MASnI3 y estudiar el efecto del resto de parámetros de diseño en el rendimiento de estas células solares. Hay varios softwares de simulación disponibles que se utilizan para el análisis numérico de células solares. En este trabajo hemos usamos un software llamado "A Solar Cell Capacitance Simulator" (SCAPS), está disponible de forma gratuita y es muy popular entre la comunidad científica y tecnológica. Para lograr un diseño efectivo para una célula solar eficiente, se propuso una aproximación numérica basada en la mejora de la PCE de una célula solar experimental. Esto se hizo reproduciendo los resultados para la célula solar diseñada experimentalmente en un entorno SCAPS con estructura p-SnS / n-CdS con una eficiencia de conversión del 1,5%. Después de la reproducción de los resultados experimentales, el rendimiento del dispositivo se optimizó ajustando el grosor de la capa absorbente y la capa tampón, la el tiempo de vida de los portadores minoritarios, la concentración del dopado en las capas absorbente, tampón y en la capa de la ventana. Mediante la optimización gradual de los parámetros del dispositivo, se alcanzó un valor de 14.01% en PCE de células solares diseñadas con SCAPS con arquitectura p-SnS / n-CdS / n-ZnO. A partir del análisis, se encontró que la PCE de una célula solar depende en gran medida de la concentración de dopaje de la capa absorbente, el espesor de la capa absorbente y los defectos de la interfaz. Sobre la base de los resultados obtenidos, se realizó un análisis para determinar el efecto de la recombinación de la interfaz en el rendimiento de las células solares y cómo se puede controlar. Para realizar esta tarea, se realizó un análisis para la selección de la capa tampón adecuada para la célula solar de perovskita metilamonio de estaño y yodo (MASnI3) y se encontró que el PCE de la célula solar también depende de la alineación de la banda entre el absorbedor y la capa de tampón. Por otra parte, se ha propuesto una nueva estructura para la célula solar de perovskita libre de Pb (contacto posterior / MASnBr3 / MASnI3 /CdZnS / FTO) con un PCE de 18.71% para un espesor del absorbedor de 500 nm y una concentración de dopado en el aceptor de 1x1016 cm-3. Los resultados obtenidos en esta tesis proporcionarán una guía para que los investigadores experimentales puedan construir células solares más eficientes.<br>[CAT] Des de fa una dècada s'està investigant intensament la forma de millorar l'eficiència de conversió d'energia (PCE) de les cèl·lules solars de silici (Si) i reduir els seus preus. No obstant això, tot i les millores obtingudes, la fabricació de cèl·lules solars de Si segueix sent costosa i pot rebaixar-se usant materials en forma de capa fina. Per això la recerca de materials absorbents alternatius, no tòxics, abundants en la naturalesa i amb bons rendiments de conversió s'ha intensificat en els últims anys. Entre els diferents materials absorbents, el sulfur d'estany (SnS), amb una banda prohibida de 1.3 eV propera a l'òptima, és un candidat adequat per a la conversió fotovoltaica. Però per a cèl·lules experimentals de SnS el rendiment assolit fins ara és de 4.6%, que és molt menor que el PCE per a dispositius de silici, mentre que entre altres cèl·lules híbrides (orgàniques-no orgàniques) com la perovskita de metilamonio de plom i iode ( MAPbI3) es demostra que és un candidat adequat amb PCE que arriba a un valor del 23%. A part de l'estabilitat, un dels problemes per a la comercialització de cèl·lules de MAPbI3 és la naturalesa tòxica del plom (Pb). Per aquest motiu, s'ha utilitzat l'anàlisi numèrica per revisar els paràmetres de disseny de les cèl·lules solars de perovskita híbrida substituint l'absorbent MAPbI3 per MASnI3 i estudiar l'efecte de la resta de paràmetres de disseny en el rendiment d'estes cèl·lules solars. Hi ha diversos programaris de simulació disponibles que s'utilitzen per a l'anàlisi numèric de cèl·lules solars. En aquest treball hem fem servir un programari anomenat "A Solar Cell Capacitance Simulator" (SCAPS), està disponible de forma gratuïta i és molt popular entre la comunitat científica i tecnològica. Per aconseguir un disseny efectiu per a una cèl·lula solar eficient, es va proposar una aproximació numèrica basada en la millora de la PCE d'una cèl·lula solar experimental. Això es va fer reproduint els resultats per a la cèl·lula solar dissenyada experimentalment en un entorn SCAPS amb estructura p-SnS / n-CdS amb una eficiència de conversió de l'1,5%. Després de reproduir els resultats experimentals, el rendiment del dispositiu es va optimitzar ajustant el gruix de la capa absorbent y de la capa tampó, el temps de vida dels portadors minoritaris, la concentració del dopatge en les capes absorbent, tampó i en la capa finestra. Mitjançant l'optimització gradual dels paràmetres del dispositiu, es va assolir un valor de 14.01% en PCE de cèl·lules solars dissenyades experimentalment en SCAPS amb arquitectura p-SnS / n-CdS / n-ZnO. A partir de l'anàlisi, es va trobar que la PCE d'una cèl·lula solar depèn en gran mesura de la concentració de dopatge de la capa absorbent, el gruix de la capa absorbent i els defectes de la interfície. D'altra banda, es va realitzar una anàlisi per determinar l'efecte de la recombinació de la interfície en el rendiment de les cèl·lules solars i com es pot controlar. Per realitzar aquesta tasca, es va realitzar una anàlisi per a la selecció de la capa tampó adequada per a la cèl·lula solar de perovskita de metilamoni d'estany i iode (MASnI3) i es va trobar que el PCE de la cèl·lula solar també depèn de l'alineació de la banda entre l'absorbidor i la capa de tampó.<br>[EN] A decade of extensive research has been conducted to enhance the power conversion efficiency (PCE) of silicon (Si) solar cells and to cut their prices short. But still, the fabrication of Si solar cells are costly. So, to reduce the fabrication cost of the solar cell search for alternate earth abundant and non-toxic absorber materials is thriving. Among different absorber materials tin sulfide (SnS) is found to be a suitable candidate for the non-organic solar cell with a band gap of 1.3 eV. But the PCE achieved for SnS is 4.6% that is far less from the PCE of (Si), whereas among other organic non-organic solar cells like methylammonium lead halide perovskite ({\rm MAPbI}_3) is proven to be a suitable candidate with PCE reaching to a value of 23%. The problem with the commercialization of {\rm MAPbI}_3 is due to the toxic nature of lead (Pb). So, in dealing with these issues of solar cell numerical analysis can play a key role as numerical analysis allows flexibility in the design of realistic problem and experimentation with different hypotheses can easily be performed. Complete set of device characteristic can often be easily generated by consuming less amount of time and effort. Because of this reason numerical analysis was used to revisit solar cells design parameters and the effect of solar cell physical parameters on solar cell performance. There are various simulation software's available that are used for solar cell numerical analysis. Here in this work, we used Solar cell capacitance simulator (SCAPS) software, it is freely available and is most popular among the research community. To achieve effective design for efficient solar cell a numerical guide was proposed based on which PCE of an experimental designed solar cell can be enhanced. This was done by reproducing results for the experimentally designed solar cell in SCAPS environment with structure p-SnS/n-CdS having a conversion efficiency of 1.5%. After reproduction of experimental results device performance was optimized by varying thickness of (absorber layer, buffer layer), minority carrier lifetime, doping concentration (absorber, buffer), and adding window layer. By stepwise optimization of device parameters, PCE of an experimental designed solar cell in SCAPS with architecture p-SnS/n-CdS/n-ZnO was reached to a value of 14.01%. From the analysis, it was found that PCE of a solar cell is highly depended upon doping concentration of the absorber layer, the thickness of the absorber layer and interface defects. Based on the results evaluated an analysis was performed for tin based organic non-organic methylammonium tin halide perovskite solar cell ({\rm MASnI}_3) to find the effect of interface recombination on solar cell performance and how it can be governed. The reason for this transition from SnS to {\rm MASnI}_3 was because {\rm MASnI}_3 can be fabricated simply by spin-coating methylammonium iodide (MAI) over SnS layer. To perform this task analysis was performed for the selection of suitable buffer layer for Pb free methylammonium tin halide perovskite solar cell ({\rm MASnI}_3) and it was found that PCE of the solar cell is also depended upon band alignment between absorber and buffer layer. Based on the results a new structure was proposed for Pb free perovskite solar cell (Back\ contact/{\rm MASnBr}_3/{\rm MASnI}_3/CdZnS/FTO) with PCE of 18.71% for absorber thickness of 500 nm and acceptor doping concentration of 1x10^{16}\ {\rm cm}^3. The results achieved in this thesis will provide an imperative guideline for researchers to design efficient solar cells.<br>Baig, F. (2019). Numerical analysis for efficiency enhancement of thin film solar cells [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/118801<br>TESIS

Thin films of organic semiconducting materials, such as copper phthalocyanine (CuPc) and C60, can be used in photovoltaic devices. The interface between these materials is the site of exciton dissociation, and thus a key region of interest in their study. The processes that occur within these films and at interfaces are governed by the local morphology and structure. Studying these films and interfaces at high spatial resolution has previously been challenging given their soft nature and scale. Using electron transparent cross-sections prepared with a focussed ion beam (FIB), high resolution transmission electron microscopy (HRTEM) has been used to probe the local crystallography of three archetypical organic photovoltaic device structures grown on silicon and indium tin oxide (ITO). In HRTEM images lattice fringes of unprecedented clarity are observed, validating the optimised FIB method. HRTEM examination of device structure cross-sections on silicon reveals lattice fringes throughout pure films of CuPc and C60. The structure of the CuPc thin film can be correlated with bulk characterisation methods however, the observation of stacking faults demonstrates film non-uniformity. Lattice fringes in C60 films show an orientation preference with respect to the interface, which allows conclusions to be made about C60 when grown on molecular films. Mixed films show no lattice fringes. Structures grown on ITO are more complex than those on silicon, which is attributed the relatively rougher growth surface. Due to this rougher surface, the morphological changes occurring result in reduced crystallinity, a conclusion supported by bulk characterisation methods. The cross-sectional methodology has been extended to thicker films, revealing the presence of structural deviations that lie parallel to the surface. Scanning transmission electron microscopy, in combination with energy dispersive X-ray spectroscopy, high resolution quantitative compositional mapping reveals the morphology of the interface for the structures studied. This been correlated with the morphology of single CuPc film surfaces, with the conclusion that morphology of the CuPc surface remains unchanged after C60 film growth.

Ballute hypersonic aerodynamic decelerators have been considered for aerocapture since the early 1980's. Recent technology advances in fabric and polymer materials as well as analysis capabilities lend credibility to the potential of ballute aerocapture. The concept of the thin-film ballute for aerocapture shows the potential for large mass savings over propulsive orbit insertion or rigid aeroshell aerocapture. Several technology hurdles have been identified, including the effects of coupled fluid structure interaction on ballute performance and survivability. To date, no aeroelastic solutions of thin-film ballutes in an environment relevant to aerocapture have been published. In this investigation, an aeroelastic solution methodology is presented along with the analysis codes selected for each discipline. Variable-fidelity aerodynamic tools are used due to the long run times for computational fluid dynamics or direct simulation Monte Carlo analyses. The improved serial staggered method is used to couple the disciplinary analyses in a time-accurate manner, and direct node-matching is used for data transfer. In addition, an engineering approximation has been developed as an addition to modified Newtonian analysis to include the first-order effects of damping due to the fluid, providing a rapid dynamic aeroelastic analysis suitable for conceptual design. Static aeroelastic solutions of a clamped ballute on a Titan aerocapture trajectory are presented using non-linear analysis in a representative environment on a flexible structure. Grid convergence is demonstrated for both structural and aerodynamic models used in this analysis. Static deformed shape, drag and stress level are predicted at multiple points along the representative Titan aerocapture trajectory. Results are presented for verification and validation cases of the structural dynamics and simplified aerodynamics tools. Solutions match experiment and other validated codes well. Contributions of this research include the development of a tool for aeroelastic analysis of thin-film ballutes which is used to compute the first high-fidelity aeroelastic solutions of thin-film ballutes using inviscid perfect-gas aerodynamics. Additionally, an aerodynamics tool that implements an engineering estimate of hypersonic aerodynamics with a moving boundary condition is developed and used to determine the flutter point of a thin-film ballute on a Titan aerocapture trajectory.

The recent developments of high resolution flat panel imagers have prompted interests in fabricating smaller on-pixel transistors to obtain higher fill factor and faster speed. This thesis presents fabrication and modeling of short channel amorphous silicon (a-Si:H) vertical thin film transistors (VTFT). <br /><br /> A variety of a-Si:H VTFTs with different channel lengths, from 100 nm to 1 &mu;m, are successfully fabricated using the discussed processing steps. Different structural and electrical characteristics of the fabricated device are measured. The results of I-V and C-V characteristics are comprehensively discussed. The 100 nm channel length transistor performance is diverged from regular long channel TFT characteristics, as the short channel effects become dominant in the device, giving rise to necessity of having a physical model to explain such effects. <br /><br /> An above threshold model for a-Si:H VTFT current characteristics is extracted. The transport mechanisms are explained and simulated for amorphous silicon material to be used in the device model. The final model shows good agreement with experimental results. However, we used numerical simulation, run in Medici, to further verify the model validity. Simulation allows us to vary different device and material parameters in order to optimize fabrication process for VTFT. The capacitance behavior of the device is extensively studied alongside with a TFT breakdown discussion.

In this master thesis, electrical characterization of thin film CuInxGa(1−x)Se2 solar cells produced by Midsummer AB were performed with the aim of determining the dominant recombination path of these cells. Current-Voltage (IV), Quantum Effinciency (QE), temperature dependent IV (IVT) and Drive-Level Capacitance Profiling (DLCP) was used with the objective to investigate the dominant recombination path as well as provide some insight of the solar cells in order to create a baseline model using the modelling software SCAPS (Solar cell CAPacitance Simulator). The IV produced mostly consistent results with slight variation, most likely due to non uniformity of equipment. The QE showed consistent results between all cells indicating a stable process for the sample preparation. Using IVT measurements were taken from a temperature of 115K −300K in order to obtain the activation energy for the dominant recombination path. By comparing it with the band gap energy from the QE measurement, it was found that the dominant recombination path is in either the space charge region or in the bulk of the CIGS and not at the hetero interface. DLCP measurement were made at both low temperature and at room temperature and revealed that the cells had a similar doping as other comparable cells at 7×1016cm−3 . The initial baseline model created in SCAPS show a good agreement with the measured IV and currently indicates a spike in the band alignment, supporting the results for the IVT measurement.

碩士<br>國立清華大學<br>電子工程研究所<br>94<br>Research work, we grew the silicon thin films with different hydrogen dilution ratio by electron cyclotron resonance chemical vapor deposition (ECR-CVD). The crystalline fraction, bonding configurations, crystalline orientation and grain size, film thickness, dark and light conductivities of the silicon thin films were measured and analyzed by the Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray Diffraction (XRD), α-STEP and I-V measurement respectively. In the experiment, we fixed the substrate temperature at 250oC, the process pressure at 20mtorr, the microwave power at 1150W, the Top/ Middle/ Bottom magnetic current at 170/170/30A and varied the hydrogen dilution ratio from 40% to 98%. Beside, we also doped the films using phosphine (PH3) and diborance(B2H6) to form the n-type and p-type silicon thin film. The four point probe was used to analyze the resistivity. From the experimental results, we find the fact that the maximum grain size was found to be about 251Ǻ and the maximum crystalline fraction was about 91% when the hydrogen dilution ratio was 92%. AFORE-HET was used to simulate the optimum thickness of the device structure and followd the simulated result to fabricate the silicon thin film solar cell. The P-type amorphous silicon was used as a window layer and microcrystalline silicon as I and N layer. From I-V characteristics of the device, the open circuit voltage obtained is 0.112mA/cm2, the short circuit current is 0.4V and the fill factor is 21.35%. The device characteristics can be improved by improving the quality of the material.

碩士<br>逢甲大學<br>自動控制工程學系<br>105<br>MEMS thin film capacitor structure, often used in a variety of different aspects, is now in the nano world view, the capacitance components are miniaturized, same size can be placed under the larger capacity, the function can be more, However, the structure of the film is different, in different circumstances will require different capacitance capacity, according to the different bearing capacity of the thin film structure will have a different process, with a smaller volume to achieve the required capacity, the tiny capacitor components market needs to grow, in this regard to the typical four kinds of thin film capacitor structure for discussion. This study presents a typical thin film capacitor element analysis, divided into three kinds of analysis, the first: four typical thin film structure, in the same conditions under which the structure of the largest capacity, the second: the same kind of film structure, there are three different electrode spacing variations in the three fixed areas, a thin film structure will have nine capacitance results, according to these data to analyze the capacitance of the thin film capacitance and capacitance growth rate, The third: to explore the reality with the simulation of the difference in capacitance, the difference in the capacitance value lies in the fringing effect of the electrode edge, which determines the effective increase in the edge length and can increase the total capacitance value per unit area. The thickness of the deep trenches in the four thin film structures is the largest, but there is a problem with high aspect ratio, step coverage process, serpentine capacitance is second only to deep trenches, but it also has drawbacks, as long as part of the damage will be the whole can not operate, relative to the cost of the risk of interdigital structure will be more suitable, because the process is relatively simple part of the structural damage, but also to maintain a large part of the capacity. Finally, the parallel plate electrode is divided into equal blocks, the more the electrode segmentation, the fringing effect increases, capacitance is also relatively increased, but there are limits, today's technology and process limits with the original area of the cutting line of the loss of capacity, to a certain extent will be with the edge effect of the increase in capacitance to eliminate.

碩士<br>國立成功大學<br>機械工程學系<br>88<br>Mechanical property in thin film structures has attracted great interest issues. The primary concern is the deleterious effects induced by stress in films. Therefore, to minimize and control the stress it is important to understand the type, magnitude and origin of various stress. The second important concern is to enhance the mechanical properties of hardness and wear resistance. The topic of stress in film is the major interest in this thesis. Essentially all films are in a state of stress after vacuum deposition. Stress of most sputtered film is compressive. In many cases, the stress is high enough that it can cause the film to fail mechanically. For example, peeling, generation of crystalline defects and formation of film surface growths such as hillocks whiskers are the typically consequence of excessive stress. Normally, the total stress of a thin film may be composed of intrinsic stress, thermal stress and water absorption induced stress. For single thin film, residual stress can be measured with a X-ray diffraction or mechanical “bending plate method”. But for multilayer, it is very important to establish a model to calculate the residual stress. In this thesis, a mathematics model is used to evaluate the distribution of stress in multilayer.

碩士<br>中華技術學院<br>電子工程研究所碩士班<br>96<br>With global energy crisis, the rising of environmental awareness, surging of oil prices, and the signing of Kyoto Protocol, as well as the subsidized use of solar energy in the U.S. and EU, the adoption and the research of solar cells have become increasingly important. Experiment One – The objective of this thesis is to use DC Sputter to deposite copper indium gallium diselenide (also known as CIGS) thin film on plastics, P-SI and glass substrates. As a I-III-VI2 quaternary compound, CIGS possesses the advantages of high absorbance, low cost and easy processing. The lattice direction of an excellent CIGS thin film should contain 112 facets. In this experiment we use X-ray diffraction (XRD) to analyze, and then choose substrate with 112 facets for further experimental analysis. Furthermore, We use DC Sputter to deposit copper indium gallium diselenide thin film onto plastic substrate, then conduct Hall Measurement with parameters of difference processes to analyze whether the CIGS thin film possesses good majority carrier content, low resistance, P/N type and majority carrier mobility. Next, we measure the thickness of the thin film with the Spectra Thick Series, analyze the thin film with spectroscope, convert and calculate the energy gap and then observe the crystalline facet structure with XRD. Combining results from all the analysis and measurements described above, we can then analyze and study the deposition time, thin film thickness, and the electrical property to determine whether the deposited CIGS thin film can act as an excellent main absorbing layer of the solar cells

碩士<br>國立成功大學<br>土木工程學系碩博士班<br>94<br>In this work we employ the finite element software, ABAQUS, to simulate the stress evolution in film-substrate system subject to intrinsic mismatch strains. The mismatch strain could be origined from surface stress, different thermal expansion coefficients, and others. In pratical situations it is difficult to measure the stress in situ. The renowned Stoney formula provides a simple analytical connection between the internal stress and the curvature of the substrate, and thus could serve as a convenient tool to estimate stress through the measured curvature. However, the derivation of the Stoney formula was based on classical plate assumptions. In addition, the energy terms associated with the film deformation are all neglected. Naturally, this formula, though simple, could only be valid under certain conditions. Here we employ the finite element analysis to examine the range of validity of Stoney formula.

碩士<br>國立中央大學<br>化學工程與材料工程學系<br>106<br>The research can be divided into two parts. The first one is Solution-processable low-voltage driven transparent oxide thin film transistor. The second is Donor Acceptor and linkage effect for transistor type memory devices application. In the first part, we use ITO glass as substrate and gate. Then, about 120 nm TSO thin film was deposited on ITO glass. Its capacitance is approximately 172 nF cm-2, dielectric constant is 27.5. The TSO/ITO glass substrate was preheated to 400 oC, and then 65 nm ZnO semiconductor layer was deposited on it by using spray coating method, followed by annealing at 400 oC for 1 min. The elecrtrode was fabricated by two steps. Firstly, we deposited AgNWs through a shadow mask by using spray coating method. Then, we deposited another PEDOT:PSS layer through the shadow mask on the same position as we deposited AgNWs. The operation voltage of the thin film transistor is only 3 V, on/off current ratio 105, threshold voltage 0.36 V, subthreshold swing 815 mv dec-1, electron mobility 9.1 cm2 V-1 s-1. The results show the thin film transistor possessed well electrical characteristics and was stable under ambient air while doing experiment. In the second part, we use SiO2/Si as substrate and deposited electret by using spin coating method. Electret layer is fabricated for the purpose of storing holes or electrons. In this work, the electrets are TPA-PIS (Triphenylamine Sulfonyl-containing polyimide)、TPA-PES (Triphenylamine Sulfonyl-containing polyether) and TPA-PETS (Triphenylamine Sulfonyl-containing polyester), respectively. By researching and analyzing the electric characteristics and structure effects, we can be told that transistor type memory devices based on the three materials are all volatile memory. Yet, different structure, energy level or other relative characteristics can influent electric characteristics of transistor type memory. Therefore, we can learn knowledge by analyzing the relationships between structure and its effects on memory characteristics.

碩士<br>國立臺灣科技大學<br>電子工程技術研究所<br>86<br>The purpose of this thesis is to analyze numerically the characteristics of about optical thin film components in Matlab language. We can use the simplest way to get accurately results. This thesis is mainly divided into 2 parts. First of all, we began with Maxwell equations and optical admittance theorem to infer optical matrix formula. And then, we design some programs to simulate optical thin film experimental results based on this theorem. We make the further analysis and research of thin film optical components : anti-reflection coatings, high-reflectance coatings, neutral beam splitters, bandpass filter, highpass filter and lowpass filter. The characteristics include reflection Secondly, we also investigate an new analytic method for calculating optical constants of weakly absorbing film, which in developed by Yanfei Zheng and Kazuo Kikuchi in 1997 . We check its accuracy by using the former programs and make a disscussion about this way, and compare the results of this analytic method with those obtained from matrix method.

碩士<br>清雲科技大學<br>電機工程研究所<br>93<br>Recently, poly silicon thin film transistors (poly-Si TFTs ) have been applied in many aspects such as such memory, active matrix liquid crystal display (AMLCDs) and so on. Main reason for this because the field effect mobility of poly-Si TFT is almost 100 times higher than that of amorphous silicon thin film transistor. Among different applications, poly Si TFT has been utilized to manufacture pixel switching devices and display-related peripheral driver circuits. It is realized that, with the technology of poly Si TFT, fabrication of large area flat panel liquid crystal display based on glass structure has been a long term trend. Thus, it is very important to focus studies on reliability and electrical characteristic of poly Si TFT. In this thesis, the aim is to study reliability of thin film transistors under different voltage conditions. Measure of reliability is based on performance at various channel dimensions. Since properties of poly Si TFT like threshold voltage, electrical mobility, subthreshold swing etc. will be degraded due to hot carrier effect, it is the main target to investigate the defect energy gap distribution raised from that effect through electricity analysis. The relationship between operation voltage and defect density will be established as well in this research. It is hoped that information resulted from this thesis can be useful for technology and product development in TFT industry.

碩士<br>國立中央大學<br>機械工程研究所<br>91<br>Microelectromechanical systems is a new field in the world now,it use micro-technology,system technology,materials and effect technology, manufacture microsensors,signal processor,and microactuators.The research I make is to study "use thermal oxidation method to form titanium dioxide and its materials character and analysis" .The experiment parameters including:temperature, oxygen flow,pressure.The main parameters are temperature,oxygen flow ,and pressure affects small.When titanium dioxide thin film is formed, furthermore,to measure resistivity,measure contact angle,analyze XRD,analyze FTIR.After resistivity measurement,if titanium deposit on silicon substrate directly,then resistivity increases when oxygen flow increases.If titanium deposit on silicon substrate directly,then resistivity increases when temperature increases,but sometimes has exception when temperature is 600℃,because has formed titanium silicide.If titanium deposit on oxide,compare with titanium deposit on silicon substrate,after oxidation,the former has higher resistivity.According to contact angle measurement ,if protein can react with titanium dioxide,the protein must be hydrophilic,otherwise,if it is hydrohobic,it can`t react with titanium dioxide. After measurement,the PVD method has smaller contact angle than CVD method.It shows PVD method has better hydrophilic.According to XRD analysis, when 2Θ=25°,it has anatase(101)peak,when 2Θ=48°,it has anatase(200)peak,when 2Θ=54°,it has anatase(105)peak.Finally,after FTIR analysis, CVD method has stronger peak than PVD method,when temperature increase,no matter PVD method or CVD method,they have stronger peak.

碩士<br>大葉大學<br>電機工程研究所<br>89<br>Abstract Recently , Poly-silicon Thin Film Transistors have received extensive attention for their potential application in the printhead , imager , large-size active-martix liquid crystal display (AMLCD) . Typically , TFT operates with a floating substrate and the operation bias is about 12V . Moreover , the characteristics of TFT are severely affected by material properties of poly-silicon . As a result , the characteristics of a TFT cannot be accurately modeled by the common bulk MOSFET model in SPICE . Quite a few circuit models for low temperature ploy-silicon TFT have been reported, but very few of them took the temperature effect into account . So far , none have been implemented into commercially available circuit simulator with temperature dependent features . The work attempt to develop a physically-based analytical current-voltage model and an instrinsic capacitance-voltage model of poly-Si TFT for circuit simulation . First , we have developed a set of programs including I-V and C-V models and parameter extraction methods . The model parameters are extracted from the experimental data and then substituted back into the developed models . The accuracy of these models were successfully implemented in MEDICI , TSUPREM4 , AIM-SPICE . The experimental data used here are measured from a AMLCD wafer with p-substrate and undergate structure . The device models are finally implemented in the AIM-SPICE circuit simulator to predict and analyze the circuit performance of poly-si TFT . A model , is described for applications from the subthreshold to saturation regions that is continuous and differentiable , is suited for MEDICI , TSUPREM4 , AIM-SPICE circuit simulator , in this thesis . Channel Length Modulation (CLM) , Velocity Saturation (VS) , Kink Effect (KE) , Temperature Dependence Effect (TDE) , Drain Induced Grain Boundary Potential Barrier Lowering (DIBL) , Gate Induced Grain Boundary Potential Barrier Lowering (GIBL) , Hot Carriers Effect (HCE) are discussed and modeled .

博士<br>國立東華大學<br>電機工程學系<br>106<br>The two-step process including the deposition of the metal precursors followed by heating the metal precursors in a vacuum environment of Se overpressure was employed for the preparation of Cu(In,Ga)Se2 (CIGS) films. The correlations among the two-step process parameters, film properties, and cell performance were studied. The results demonstrated that the CIGS films selenized at the relatively high Se flow rate of 25 Å/s exhibited the improved surface morphologies. With the given selenization conditions, the efficiency of 12.5% for the fabricated CIGS solar cells was achieved. The features of co-evaporation processes including the single-stage, bi-layer, and three-stage process were discussed. The characteristics of the co-evaporated CIGS solar cells were presented. Not only the surface morphologies but also the grading bandgap structures were crucial to the improvement of the open-circuit voltage of the CIGS solar cells. Efficiencies of over 17% for the co-evaporated CIGS solar cells have been achieved. Furthermore, the critical factors and the mechanisms governing the performance of the CIGS solar cells were addressed. In addition, a baseline model and an advanced model of CdTe solar cells with the selected semiconductor properties fitting to the performance parameters of the champion CdTe solar cells were developed. The responsible factors for the efficiency improvement of the high-performance CdTe solar cell were analyzed. The thin CdS films, and the low defect densities and high carrier mobilities of the CdS films were the crucial factors for the enhancement of the short-circuit current density. With the suppression of carrier recombination, the open-circuit voltage and the fill factor of the CdTe solar cells with the low defect densities in either CdTe films or interdiffusion layer were enhanced. Furthermore, the carrier collection was impeded for the interdiffusion layer with a high defect density, leading to a decrease in the short-circuit current density. Moreover, the simulation results revealed that the efficiency of 20-21% was achieved for the CdTe solar cells with the low defect densities and the high carrier concentrations of the CdTe films.

碩士<br>國立臺灣大學<br>應用力學研究所<br>92<br>Micro Electromechanical Technology has made great progress，using the Process-skill to manufacture Electrical-Igniting-Chip to replace an old Exploding-Bridge-Wire，Electrical-Igniting-Chip has the advantage of lower firing energy、shorter ignition time、higher exploding temperature, etc. To switch an air bag of cars，to ignite bombs and rockets，to burn blunt master explosive，to ignite fuel to push ahead and is a kind of more reliable product. When it is an military use，it is set on an ignition device which has the ignition powder Zr in it ,and the Exploding Bridge Wire must pass the military standard of low firing energy test、low ignition time test、avoiding electrostatic discharge test and avoiding electromagnetic disturbing. In the manufacture of semiconductor process,use the process of yallow light、the process of thin film、the process of lift off to manufacture the Exploding Bridge Wire. And have successfully manufacture the golden Exploding Bridge Wire, the size of it is 30μm in wedth and 600μm in lenth. The single Exploding Bridge Wire is single or is parallel connection of two、three and four Exploding Bridge Wire,and each resistences is about 14Ω、7Ω、4.5Ω、3Ω. In the respect of firing energy and ignition time, this paper use the idea of mathematical method, use the formulas for Electrical Gurney Energy and Electrical Heat to analyse the ignition time、firing energy and exploding temperature of ten kind of metal of the every Exploding Bridge Wire size. Change the parameter of RCL discharge system to get the numerical solution, from the solution to find the material and size of low firing energy and high exploding temperature, and it is a reverse engineering. In the respect of avoiding electrostatic discharge causing the accident of ignition of Zr , use the Zenor diode of backward direction and RC discharge circuit , the discharged current of low voltage of capacitance doesn’t pass the RC element connected to ground terminal, and ignite the Exploding Bridge Wire. Thousands of electrostatic voltage break down the zenor diode of backward direction , and electrostatic voltage discharge in Exploding Bridge Wire in nano seconds to avoid electrostatic voltage igniting. We analyse the electrostatic voltage discharge in 1 sec by using the numerical method,to caculate the time constant of RC circuit. It shows that the time constant of RC circuit should be about 0.26 nano second to satisfy both conditions, the temperature of Exploding Bridge Wire is lower than the ignition temperature of the powder of Zr, which is 300℃, and the voltage of Exploding Bridge Wire is lower than the military standard of the safe electrostatic voltage .

碩士<br>國立交通大學<br>管理學院碩士在職專班科技管理組<br>96<br>The solar cell industry in Taiwan has been developing since 1999. Today, in 2008, 8 suppliers exist in the upper-stream of wafer supply, 20 suppliers are devoted or planning to invest in mid-stream, solar cell technology, 20 suppliers are devoted or planning to invest in mid-stream system integration and over 50 suppliers are invested in the down-stream of product application or related accessories industries. In these few years, the number of suppliers in the solar cell industry has risen to almost one hundred and the yearly production revenue is over 10 $NT billion. Over the past nine years, the entire industry supply chain was established and the industry cluster was also strengthened. The annual revenue of the solar cell industry will exceed that of the LED industry in the near future. Additionally, Taiwan was ranked fifth in the world among solar cell producing countries. Over the past decade, wafer-based crystalline silicon solar modules have predominantly been the material of choice in production; however, due to a major material supply shortage in silicon, used to produce silicon wafers, a significant shift in production methods could be on the horizon. Amorphous silicon (a-Si), Cadmium telluride (CdTe) and copper indium diselenide (CulnSe2, CIS), used to produce thin film solar cells, have the potential to become more commercialized and have maintained a significantly higher growth rate than silicon-based solar cells. An overwhelming majority of silicon-based solar cell suppliers are planning to change to the thin film solar cell field and intend to follow the turnkey model to establish the production line more easily and smoothly. This thesis analyzes the comparative competitive advantage among main solar cell producing countries. It is comprised of historical data, comparing Taiwan’s thin film solar cell development and growth with that of other countries throughout the world, investigating competitiveness from both a global perspective and a country perspective from Taiwan to induce a competitive advantage in the thin film solar cell market. Furthermore, this thesis provides strategic suggestions for the potential manufacturers as well as government regulators.

碩士<br>中原大學<br>電子工程研究所<br>98<br>Aluminum nitride (AlN) films were grown on Si(111) and c-plane sapphire (Al2O3) substrates by atmospheric pressure metal-organic chemical vapor deposition (AP-MOCVD) using Trimethylaluminum (TMA) and ammonia (NH3) were used as Al and N sources. SiH4 as an n-type dopant gas. In this paper we investigate the effect of different growth temperature on films and different substrates and different growth temperature, different doping quantity. We measured the structure properties by powder x-ray diffraction (XRD) and scanning electron microscope (SEM). The electrical properties by Hall measurements. We can seen change of crystallographic planes on sapphire . And on the Si(111) growth temperature 900℃ increase to 1050℃. The crystallographic planes (002) intensity increase accompany growth temperature go up. And electrical of un-doped AlN thin film evaluates conductive n-type, with resistivity, Hall mobility, and electron concentration as 3.04E-2 Ω cm, 2.175E+2 cm2/Vs, and -4.377E+14 cm-3, respectively. And can seen high quality doped-AlN films, with resistivity, Hall mobility, and electron concentration as 7.704E-3 Ω-cm, 3.875E+2 cm2/Vs, and -9.435E+18 cm-3 , respectively.

碩士<br>銘傳大學<br>電子工程學系碩士班<br>99<br>In this work, metal-insulator-metal (MIM) capacitors with MgO dielectrics were fabricated and investigated for non-volatile memory application. MgO thin films were prepared by radio frequency magnetron sputtering. The dominant conduction mechanism in the dielectric thin film is the hopping conduction at electric field higher than about 0.25 MV/cm at high resistive state. Meanwhile, the dominant conduction mechanism in the dielectric is the Ohmic conduction at electric field lower than about 0.2 MV/cm at low resistive state. The reliability characteristics of Pt/MgO/Pt devices were studied including endurance, data retention and reading durability. And the resistance switching model was discussed and observed by DC electric characteristics.

碩士<br>長庚大學<br>電子工程學研究所<br>97<br>We have investigated single crystal Mg-doped InN thin films and Mg-doped InN/GaN Schottky junction. Mg-doped InN thin films were grown on sapphire substrates by metal-organic chemical vapor deposition (MOCVD) in this work. The structures of Mg-doped InN thin films were analyzed by XPS, XRD, SIMS and transport measurement, respectively. The effect of annealing temperature of Mg-doped InN thin film was studied by the measurement of their transport properties. The characteristics of Mg-doped InN/GaN Schottky junctions were studied by I-V and C-V measurement at different temperature. The properties of ohmic contact of the Mg-doped InN were analyzed by the TLM model. We obtained the following important conclusions: (1)The XPS data show the Mg+ signal in the Mg-doped InN thin film. For the sample C, the peak intensity of Mg 2p of the Mg-doped InN thin film was at 72.76 eV. The peak intensity of Mg 2s of the Mg-doped InN thin film was at 75.74 eV. For the sample D, the peak intensity of Mg 2p was at 72.74 eV. The peak intensity of Mg 2s was at 76.02 eV. (2)For the SIMS measurement, the secondary Mg ion counts are about 27350 in the sample C (Cp2Mg gas flow rate= 150sccm). The secondary Mg ion counts of the sample D(Cp2Mg gas flow rate= 200sccm) are 51700. The more of Cp2Mg gas flow rate was, the more of Mg concentration in the sample was observed in this study. (3)The Mg-doped InN thin film and InN thin film were both Wurtzite structure by the XRD measurement. The position of the InN peak(0002) from the ω-2θ diagram was not changed obviously under different annealing temperature. (4)For the annealing temperature from Hall measurement, our results show that the sample A has a best property at 400℃, with the highest mobility and the lowest sheet carrier concentration. The sample C has a best property at 25℃, with the highest mobility, the lowest sheet carrier concentration, and the lowest resistivity. The sample D has a best property at 200℃,with the highest mobility and the lowest sheet carrier concentration. (5)For Mg-doped InN/GaN Schottky junctions, the I-V measurement shows rectify behavior. We use eq(4.3) ~ eq(4.5) to analyze the rectify characteristics of sample C. At room-temperature, n is 4.333, I0 is 4.571×10-5A, RS is 3.585×104Ω, ψB0 is 4.742×10-1 eV. (6)From the I-V measurement with varying temperature, our result show that the saturation current of the Mg-doped InN thin film was small than that of InN. The ideal factor decreases with the temperature increasing, and becomes saturated approaches room temperature to be. The saturated current increases along with the temperature increasing, and series resistance decreases with increasing the temperature. The Schotty barrier height increases along with increasing the temperature. (7)For the C-V diagram, the slope of sample A does not change at -6 V ~1V. the slope of the Mg-doped InN(the sample C and D) have changed clearly at 0V ~1V. The result strongly suggests that Mg-doped InN thin film have a p-type layer under a thin n-type charge accumulation layer.

碩士<br>國立臺灣大學<br>機械工程學研究所<br>93<br>The lattice thermal conductivity of a thin film structure is a critical issue to improve the figure of merit of thermoelectric materials. The main purpose of this thesis is to re-establish a theory for calculating the in-plane lattice thermal conductivity of a thin film. The theory is constructed based on the particle-concept. The phonon Boltzmann transport equation with the relaxation time approximation is solved. For completeness and consistency, the proposed theory takes into account (i) the modification of the acoustic phonon dispersion relation due to spatial confinement, (ii) the change in the non-equilibrium phonon distribution due to partially diffuse boundary scattering, (iii) the frequency -dependence of the phonon group velocity, and (iv) the adoption of the maximum allowed wave vector in order to calculate the Debye temperature according to the modified phonon dispersion relation. From the calculations, we predict that the decrease of the phonon group velocity and the Debye temperature, the increase of the boundary roughness and the enhanced phonon scattering lead to a significant reduction of the lattice thermal conductivity. The sensitivities of the thermal conductivity on the temperature, the boundary roughness, and the film thickness agree well recent theoretical and experimental investigations.

碩士<br>國立臺北科技大學<br>能源與冷凍空調工程系碩士班<br>95<br>How to use clean energy to replace the tradition fossil fuel for avoid the pollutions will be the major topic of environment protection. Solar energy is a clean renewable energy, Easy to get and unlimited to supply are the advantages of it, and should be a greater favor for human society then using the energy effectively. Using solar cells is the only way to get the energy powerfully from the sun. They include organic solar cells, inorganic solar cells, and thin-film solar cells. If we could aim at the characteristic of all kinds of solar cells and make them perform properly, it will do the solar energy justice completely. According to resources limited and applications, it has an idea of thin-film solar cells. The efficiency of CIGS solar cells in which is the highest, even use for a long time and solar cells won’t degradation. The development of CIGS solar cells will be kept an eye in the future. Thin-film silicon solar cells eight decrease the need of silicon raw materials or also reduce the cost. Therefore, more than arising “efficiency”, “reducing the cost” is an advantage that can''t be neglected at producing solar cells in the future. Use solar cells as secondary electrical supply will decrease the damage to the environment. The research thrust of this paper is to analyze different types of thin-film solar cells to realize all the characteristics of silicon and CIGS thin-film solar cells, and compare the demand area of solar cells at the same generated power, to know which thin-film solar cell could apply solar energy effectively.

碩士<br>南台科技大學<br>奈米科技研究所<br>96<br>This research studied the titanium dioxide (TiO2) thin film, at thickness of 500nm, on ITO glass substrate, prepared by radio frequency magnetron sputtering from TiO2 target and analyzes the optical characteristics and surface morphology. The thin films were prepared at different temperatures and at two kinds of heat treatment process: (1) deposited in vacuum condition with substrate heating at temperature ranging from 100 to 400oC, (2) deposited in vacuum condition at RT and then post annealed at 100oC to 400oC in atmospheric furnace. The crystallization state of films was studied by X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). The surface morphology was evaluated with Atomic Force Microscopy (AFM), and the optical characteristics were analyzed by UV-VIS spectrometer and contact angle measurement. Analysis of the temperature and crystallization of different films were summarized as following: (1) at substrate heating below 150oC or post annealed below 250oC were amorphous. (2) at substrate heating at 150 to 300oC or post annealed at 250oC to 400oC were anatase crystalline. (3) at substrate heating from 350 to 400oC was at transitional state from anatase to rutile, above 400oC was rutile crystalline. According to the results of the SEM and XRD, the largest grain size in the film was observed on substrate heating condition at 300oC, grain size decreased above 300oC due to the transformation of crystal phase. According to the results of the AFM, the surface roughness increases with prepared temperature. In the two heat treatment process, the roughest surface occurred on thin films in anatase crystalline at 300oC. From 350 to 400oC, the roughness of films prepared by post annealing did not change too much, however for those prepared by substrate heating, the roughness decreases because of crystalline transformation. The absorptive performance was related with crystalline phase and grain size. As prepared temperature increases, the grain size increases and the band gap decreases that causes the films to absorb smaller frequency light. In the other words, the absorptive ability is red shifted to larger light wavelength. Besides, rutile phase has smaller band gap the anatase phase that resulted in red shift of absorption too. All these trends were confirmed by examining the transparency and absorptive performance of thin films between 200 nm ~600 nm on UV-VIS spectrometer. All films have good transparency about 70% above 400 nm. The hydrauphilic ability was related with crystalline phase and roughness. Better hydrauphilic ability was observed on anatase surface, however at the same temperature of different heat treatment process, the rougher surface possessed the poor hydrauphilic ability.

碩士<br>國立中興大學<br>光電工程研究所<br>99<br>This thesis simulated three solar cell structures with TCAD Tool developed by SILVACO, Inc. First, the change of HIT (hetero-junction with an intrinsic thin amorphous layer) solar cells, which combined single crystalline silicon and amorphous silicon, was probed with several variables, including thickness and carrier lifetime of single crystalline silicon, thickness, band gap and doping concentration of p-type amorphous silicon, and thickness and trap density of state of intrinsic amorphous silicon. Second, a-Si/μc-Si tandem solar cells were simulated by adding an interlayer, ITO, between top a-Si and bottom μc-Si component cells to enhanced TRJ effect and build up EQE simulation models. Finally, physical models for a-Si/a-SiGe/a-SiGe multi-junction solar cells were built up with the experiment data from ITRI.

碩士<br>國立中興大學<br>應用數學系所<br>95<br>In this study, a simple mechanical model modified from the Stoney formula is presented for the calculation of residual stresses in thin films. The Stoney formula was derived based on the assumption of equi-biaxial residual stress in thin films. According to the experiments in previous researches, this assumption is not always true. In the present analysis, the residual stresses can be different in x-axis and y-axis; thus, a set of new formulas are derived instead of a single Stoney formula. Different thin film structures are investigated to demonstrate the differences between the results obtained by the Stoney formula and those by the present method. The proposed method should be more accurate than the Stoney formula in the stress calculation of such films.

碩士<br>國立臺灣大學<br>應用力學研究所<br>92<br>Micro Electromechanical Technology has made great progress，using the Process-skill to manufacture Electrical-Igniting-Chip to replace an old Exploding-Bridge-Wire，Electrical-Igniting-Chip has the advantage of lower firing energy、shorter ignition time、higher exploding temperature, etc. To switch an air bag of cars，to ignite bombs and rockets，to burn blunt master explosive，to ignite fuel to push ahead and is a kind of more reliable product. When it is an military use，it is set on an ignition device which has the ignition powder Zr in it ,and the Exploding Bridge Wire must pass the military standard of low firing energy test、low ignition time test、avoiding electrostatic discharge test and avoiding electromagnetic disturbing. In the manufacture of semiconductor process,use the process of yallow light、the process of thin film、the process of lift off to manufacture the Exploding Bridge Wire. And have successfully manufacture the golden Exploding Bridge Wire, the size of it is 30μm in wedth and 600μm in lenth. The single Exploding Bridge Wire is single or is parallel connection of two、three and four Exploding Bridge Wire,and each resistences is about 14Ω、7Ω、4.5Ω、3Ω. In the respect of firing energy and ignition time, this paper use the idea of mathematical method, use the formulas for Electrical Gurney Energy and Electrical Heat to analyse the ignition time、firing energy and exploding temperature of ten kind of metal of the every Exploding Bridge Wire size. Change the parameter of RCL discharge system to get the numerical solution, from the solution to find the material and size of low firing energy and high exploding temperature, and it is a reverse engineering. In the respect of avoiding electrostatic discharge causing the accident of ignition of Zr , use the Zenor diode of backward direction and RC discharge circuit , the discharged current of low voltage of capacitance doesn’t pass the RC element connected to ground terminal, and ignite the Exploding Bridge Wire. Thousands of electrostatic voltage break down the zenor diode of backward direction , and electrostatic voltage discharge in Exploding Bridge Wire in nano seconds to avoid electrostatic voltage igniting. We analyse the electrostatic voltage discharge in 1 sec by using the numerical method,to caculate the time constant of RC circuit. It shows that the time constant of RC circuit should be about 0.26 nano second to satisfy both conditions, the temperature of Exploding Bridge Wire is lower than the ignition temperature of the powder of Zr, which is 300℃, and the voltage of Exploding Bridge Wire is lower than the military standard of the safe electrostatic voltage .

碩士<br>崑山科技大學<br>機械工程研究所<br>96<br>This study is to deposit the Mo/Cu-In layer by using the vacuum Sputter and Eelectron Beam Evaporation(EBE) system, then sulfur into CuInS2 thin film. This fabrication adopts PVD method under low vacuum environment except the sulfur method under atmosphere pressure. This experimental fabrication is different to the conventional method which used Coevaporation and Selenization to fabricate the CuInSe2 thin film, it can reduce the cost and fabrication time from the present method. Because Mo layer is conventionally used as a back electrode for CIS solar cell, its main function is used as Ohm contact. This experiment uses power of 100 to 600 watt to sputter the Mo layer on glass subtract. It is found from α-step (thin film thickness) analysis that the better uniformity of Mo thin film can be obtained by using power of 600 watt. And based on the electricity characteristic analysis, it is proved that the present Mo layer and CuInS2 thin film is belong to Ohm contact. For the sulfur part, use 60 and 90 minutes as well as 425℃ can obtain better uniformity of CuInS2 phase. But In will be reduced during the sulfur process, the higher the temperature and longer the sulfur time, the worse reduction of In will be. It results in the strength reduction of CuInS2 peak. This problem can be solved by adjusting bigger proportion of In of the pre-deposited Cu-In layer. The present CuInS2 thin film is measured as P-type layer. Its carrier concentration, mobility and film electric resistance are 1019~1020(cm-3), 10-2~10-1(cm2/V-sec) and 10~102 (Ω/cm2), respectively. It is not big difference from the previous results. Thus, the method shown in present investigation is feasible.

Thin-film solar cells have the potential to significantly decrease the cost of a finished device by cutting materials cost, and the characteristics of carrier transport through a thin film can concurrently increase the device performance over that of a wafer-based cell while tolerating a higher defect density in the absorbing material. However, while silicon is an attractive material for use in solar cells due to its nearly ideal band gap for single-junction cells and its relative abundance, its inefficient absorption of infrared light necessitates the development of light-trapping techniques to avoid losses in current generation. This thesis research has focused on two important goals: the development of a scalable thin-film silicon deposition method that produces high-quality material at minimal cost, and the evaluation of light-trapping mechanisms that will increase photon absorption in these films. Hot-wire chemical vapor deposition is used to fabricate silicon thin films with high crystalline fractions even on inexpensive substrates, and films grown with appropriate growth conditions exhibit initial open-circuit voltages above 450 mV, and while challenges in passivation still exist, this research illustrates the potential of this highly scalable and inexpensive deposition technique. Silver and silicon subwavelength structures were then both fabricated and simulated on ultra-thin silicon films on SiO₂ to evaluate their potential for increasing light absorption through plasmonic and physical scattering mechanisms, and spectral response measurements demonstrate over a ten-fold increase in carrier generation with a metal nanoparticle surface array. Periodic dielectric structures exhibit Bloch modes in both measurement and simulation, with an increase in overall quantum efficiency of over 11% from both a flat silicon layer and one that is randomly textured. These results highlight the significant role of scattering particle distribution in determining the light trapping characteristics in these devices. Design guidelines have been explored for exploiting resonant modes in these structures, and this thesis demonstrates the potential for both metal and dielectric surface arrays to dramatically increase light absorption in silicon thin films.