In this study, the RF sputtering system has been investigated comprehensively. Firstly, the relationship among the thickness of dark space, DC bias and electrode area under RF discharge is discussed. The impedance matching network of RF sputtering system, the configuration of glow discharge and their related electrical parameters are introduced and illustrated. The network theorem is used to calculate the loading impedance of RF sputtering system and to design an impedance matching circuit. And then the equivalent circuit of sheath and plasma in parallel plate RF discharge is analyzed. The characteristics of gas discharge of RF sputtering system are discussed, which includes the capacitance, resistance and conductivity on different pressure and magnetic field. Due to RF sputtering system usually driven at 13.56 MHz (this is an open frequency), we also considered how to avoid the radio frequency interference. In addition, the electrical characteristics of parallel plate RF discharge are revealed under argon atmosphere, and some of the general relationships between the various measured and determined parameters are also described. Finally, the difference between real system and ideal system are reported, and how to design a system which is rugged and reliable and can be operated, literally, in ¡¨push-button¡¨fashion, has been described in detail.

In this thesis, we focus on the properties of Al-doped ZnO (AZO) thin films for opto-electronic applications. AZO films were prepared by radio-frequency sputtering on silicon and optical glass substrates with 98wt% ZnO and 2wt% Al2O3 alloy target. AZO films were prepared under various deposition parameters (RF power, background pressure, Ar flow, and substrate temperature). The optimal parameters for the conductive and transparent AZO films are power = 100W, pressure = 3mTorr, Ar flow = 5sccm, and substrate temperature 250¢J. The film exhibits the resistivity(£l) of 2.5¡Ñ10-3 Ω-cm and 85% transparency in the 400-1800nm range. To find out optimum substrate temperature for the AZO film on p-GaAs (p=2¡Ñ1018), the samples were deposited at various temperatures followed by annealing at 400¢J for 30sec. The current-voltage (I-V) characteristics were measured. AZO films make good ohmic contact to p-GaAs to act as an electrode layer. InGaAs quantum-dot solar cells of AZO contact layers have been fabricated. A high filling factor of 52% is achieved.

Tungsten trioxide (WO3) films are important for various optical devices and especially for electrochromic materials. Sputtered WO3 thin films were deposited on conductive glass substrate (ITO/glass) by RF sputtering from a WO3 target(diameter 2¡¨x 6 mm) in a reactive atmosphere of oxygen and argon flow ratio(0 to 1) mixture in a total gas pressure of 10m Torr. The RF power was 100W operating at 13.56MHz.We will improve the WO3 films by post-annealing in different atmosphere ambient. In addition, to prepare treatment solution of growing WO3 films were dissolved tungsten to aqueous which mixed hydrofluoric acid and nitric acid until it supersaturate. This solution was then diluted to 0.02 M of tungsten ions with distilled water. And we can get the treatment solution (WO3-HF aqueous). The WO3 thin films have been deposited at 40oC with the treatment solution (WO3-HF aqueous) which full of W ions, the 0.1M boric acid (H3BO3) solution and added aluminium metal by liquid phase deposition (LPD) technique. The deposition rate could be controlled to 45 nm/h. In our experiment, the WO3 films morphology and thickness was characterized by scanning electron microscopy(SEM), structure was characterized by X-ray diffraction(XRD), chemical properties was characterized by X-ray photoelectron spectroscopy(XPS) and Fourier transform infrared spectroscopy(FT-IR), optical properties was characterized by spectrophotometer(MP-100M), and electrochromic characterized by cyclic voltammetry(CHI627C). In our results, it will be improved the optical and electrochromic properties of sputtered-WO3 films by post-annealing in O2 ambient. we also have try a novel and very simple process for the thin films of WO3 by the LPD process. Adherent and conformal WO3 electrochromic films were prepared on ITO/glass from aqueous fluoride solution.

Lead zirconate titanate (PZT), in the form of both bulk and thin films, is used in most piezoelectric applications due to its high piezoelectric response coefficients. Strontium-doped lead zirconate titanate (PSZT) has shown improved piezoelectric response characteristics in bulk form. This work investigates the deposition and characterisation of PSZT in the form of thin films, and reports on results from the estimation of the piezoelectric response of these thin films using two new techniques. The influence of RF magnetron sputter deposition parameters on the composition and orientation of PSZT thin films has been studied. Investigation of the consequence of varying the oxygen partial pressure during deposition on thin film stoichiometry, the influence of the choice of metal-coated silicon substrates on thin film orientation, and the effect of post-deposition cooling rate have been used to identify optimal deposition conditions. The existence of a modified unit cell resulting from these deposition parameters has been verified, and the resulting lattice parameters were estimated. Extensive materials characterisation (using microscopy, diffraction, and spectroscopy) of the PSZT thin films deposited on gold and platinum coated silicon substrates is reported. The limited techniques available for quantitative estimation of d33 for piezoelectric thin films initiated an investigation into alternative possibilities, as a consequence of which two new techniques for piezoelectric coefficient estimation, under the inverse piezoelectric effect, have been developed. One technique capitalises on the measurement accuracy of the nanoindenter in following thin film displacement, while the other uses a standard atomic force microscope in contact imaging mode to estimate d33. The development, scope, and limitations of both techniques are discussed. The techniques developed have been used to estimate the piezoelectric response of PSZT thin films. Depending on the thin film deposition parameters and the analysis frequency, values of piezoelectric response higher than any measured for thin films on silicon have been estimated. PSZT thin films deposited on gold-coated silicon at low deposition temperatures resulted in d33 values up to 892 pm/V. The study of the piezoelectric response in the millihertz frequency regime resulted in colossal values (ranging in tens of thousands of pm/V) for PSZT thin films deposited at high temperatures on platinum-coated silicon. This was hypothesised to be a result of enhanced ferroelastic domain switching. This hypothesis was verified by reducing the clamping on domains by synthesising island-structured PSZT films and obtaining an increased piezoelectric response.

The electro-optical properties of the ZnO thin film are affected by the deposition parameters. In this study, we find the optimum growth parameters to grow high quality ZnO film. We change the RF power to adjust the surface roughness. The higher RF power will result in a higher deposition rate and rough surface roughness. We obtained an optimum surface roughness of 1.811nm at 50W RF power. The ZnO films have more than 80% transmittance in visible range, and obvious absorption in UV range. A significant peak in the wavelength of 385nm is observed in PL measurement. For the electric characteristics, the resistivity of as-grown ZnO films is high and decreases with post annealing treatment. We have obtained a minimum resistivity of 2.764¡Ñ10-2(£[-cm) at 700oC annealing treatment. Under the fixed 50RF power and 5sccm Ar flux, the optical characteristics and the crystal qualities are worse in the lower pressure (below 5mTorr). The ZnO films have lowest resistivity of 1.826¡Ñ10-2(£[-cm) in the 15mTorr and, strongest PL intensities in 25mTorr after 700oC annealing treatment. After the optimum growth condition, we enhance the optical characteristics through the surface Plasmon effect of the metal nanoparticles. The nano gold particles in the diameter of 50nm and 200-250nm can be obtained under the 5nm and 10nm Au film deposition and annealing at 700oC, respectively. For the optical characteristics, the PL intensity and optical transmittance are enhanced dependent on the size and position of the gold nanoparticles. For the electric characteristics, the n-ZnO/p-Si shows a good rectification effect. The mechanisms of current conduction are space charge current limit, and tunnel current. Sample with 50nm diameter has a significant space charge current limit mechanism. In the C-V measurement, we observed the hysteresis curve in the sample with gold nanoparticles. The sample with larger gold particles have larger memory window of ¡µVFB=0.23.

In this study, highly C-axis oriented AlN thin films stacked upon Al bottom electrode on Si and Glass substrate are deposited with Reactive RF magnetron sputtering Technique. Three different sputtering systems were utilized to evaluate the optimized growth parameters. Room temperature growth was applied to the all system. During thin film growing , the substrate bias condition, sputtering work pressure, sputtering power and the N2 concentration are those key parameters to be adjusted in order to gain smooth surface morphology and highly C-axis prefer orientation AlN thin films. The crystallography of the deposited films was analyzed by x-ray diffraction (XRD). Film surface morphology was characterized by scanning electron microscopy (SEM). Meanwhile, transmission electron microscopy (TEM) was adopted to observe the microstructure and determine the grain size of the film. The results of the XRD patterns showed that in a 17cm long sputtering working distance condition, the AlN (002) can be obtained and the peak intensity can be increased when the sputtering power was fixed meanwhile reduced the working pressure and applied the negative bias on the substrate. The surface morphology can be improved with long working sputtering distance. The micrography of the TEM reveals that there is a transition region between Al metal and AlN film. Fine column structures can be observed in the initial growth stage. The size of the grain increased as the film became thicker. Strong AlN (002) ring pattern was obtained from the region of the top of the film. It indicates that the AlN (002) will not appear till the thickness of the film reach the critical thickness.

Deposition of alumina thin films in the presence of fluorine as a method for reducing thehydrogen incorporation in the films was investigated in this thesis. Hydrogen incorporated in alumina thin films have been shown to cause a lower density and refractive index in amorphous films, assist electrical conduction through thin amorphous films as well as inhibiting the formation of the thermally stable α-phase. The depositions were made in a ultra high vacuum system where high vacuum conditions were simulated by leaking water vapor into the system. No substrate heating or substratebias was applied. Films were deposited at a range of fluorine partial pressures, from 2,5×10-6- 5×10-5 Torr, and were analyzed by elastic recoil detection analysis, nuclear reaction analysis, scanning electron microscopy and x-ray diffraction. Mass spectrometry measurements were done during the depositions to analyze the deposition process. The mass spectrometry investigations show that there is a trend of increasing O2 partial pressures with increasing fluorine partial pressures during the depositions. This is attributed to the well known reaction: 2H2O+F2→O2+4HF. However, no trend in the measured water partial pressures can be observed. The increase in the O2 partial pressure is therefore attributed to a reaction between water and fluorine on the chamber walls. The chemical analysis show that the hydrogen incorporation in the films were lowered from ~10 at.% when deposited in the presence of water vapor to ~3 at.% when deposited in the presence of water vapor and 2×10-5 Torr fluorine. The hydrogen incorporation stabilize at ~3 at.% at higher fluorine partial pressures. However, there is also a large amount of fluorine incorporated in the films, ~20 at.% with a fluorine partial pressure during the deposition of 2×10-5 Torr and ~46 at.% with a fluorine partial pressure of 5×10-5 Torr. There is a slight increase in the aluminum concentration in the films deposited with fluorine. This is attributed to bonding the hydrogen in aluminum hydroxide while the reminder forms Al2O3 or Al leading to an increase in the aluminum concentration in the film. A linear decrease in the deposition rate with increasing fluorinepartial pressures during the deposition was observed, this can be explained by sputter etching of AlFx and AlOxFy by energetic O- ions. The XRD investigation show that the films deposited with the highest fluorine partial pressures were x-ray amorphous, the films with deposited with lower fluorine partial pressures are therefore also assumed to be amorphous.

Innovation in photovoltaic technology may offer cost competitive options to other energy sources and become a viable solution for the energy and environmental challenges of the 21st century. One proposed innovative technology is based on all-silicon tandem cells, which are constructed using superlattices consisting of environmental friendly Si and its compounds. The well and barrier materials in superlattices are restricted to silicon and silicon oxide during the present study. Single crystalline Si/SiO2 quantum wells (QWs) have been fabricated by thermal oxidation of silicon-on-insulator (SOI) wafers. It is found that oxide properties in QWs are important for SOI wafers prepared by the SIMOX (Separation by Implantation of Oxygen) technique. However, QWs fabricated from SOI wafers prepared by the ELTRAN (Epitaxial Layer TRANsfer) approach show the effect of quantum confinement without evidence of strong oxide interfacial transitions. In these wafers, evidence for an apparently ordered silicon oxide was found with 1.92?atomic fringe spacing along the (110) direction of the Si structure and with the thickness about 17?along the (100) direction of the Si structure. Luminescence wavelength ranges are from 700nm to 918nm depending on the Si thickness. The luminescence measurements on other positions of the sample show peak and shoulder spectra, which are explained by monolayer fluctuations in QW thicknesses, previously observed in III-V QWs and II-VI QWs. Si/SiO2 superlattices are fabricated by RF magnetron sputtering. Si density is the key issue in crystallizing the superlattice. High-density Si layers crystallize either under high temperature furnace annealing or rapid thermal process annealing. However, low density Si would not crystallize even at high temperature. Crystallized nanocrystals in the Si layers are observed by high resolution transmission electron microscopy (HRTEM) when the Si layer is thicker than 3nm. When Si layers are thinner than 3nm, the Si layers are discontinuous and finally deteriorate into small nanocrystals. The suitability of such superlattices for surface passivation and antireflection coatings is reviewed. Initial attempts to fabricate heterojunctions between Si wafers and Si/SiO2 superlattices resulted in open circuit voltage of 252mV. However, it is expected that better results would be obtained if Si/SiO2 superlattices were fully crystallized.

Solid Oxide Fuel Cells (SOFCs) are devices that directly convert chemical energy into electrical energy, without proceeding through a Carnot combustion cycle. These devices are based on the usage of solid oxide electrolytes operating at relatively elevated temperatures. Two major hurdles must be overcome in order to decrease the operating temperatures of practical SOFCs. The first relates to reducing ohmic losses within solid electrolytes. The second relates to the need for developing high performance electrodes since electrolyte reaction rates at both anode and cathode are affected detrimentally as operating temperatures fall. This PhD project has focussed on addressing the first hurdle in two innovative ways: 1. the implementation of solid electrolytes with higher ionic conductivity than zirconia, 2. the development of very thin film electrolytes as thick as 5ƒÝm. Several thin films with novel electrode-electrolyte structures were fabricated and evaluated in order to demonstrate the viability of low temperature SOFC operations. Development of such thin films was innovative and challenging to achieve. The approach taken in this work involved fabricating a dense and thin gadolinia doped ceria (10GDC - Gd 10wt%, Ce 90wt%) oxide electrolyte. 10GDC is an electrolyte exhibiting higher conductivities than conventional materials during low temperature operations. A research contribution of this PhD was the demonstration of the deposition of 10GDC thin films using RF magnetron sputtering for the first time. 10GDC thin film electrolytes with thickness in a range between 0.1 to 5ƒÝm were fabricated on 10 yttrium stabilised zirconium (10YSZ) substrates by using a RF magnetron sputterer. The primary parameters controlling 10GDC thin film deposition using this method were explored in order to identify optimal conditions. The fabricated films were subsequently analysed for their morphology, composition and stoichiometry using a variety of methods, including Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectrometry (EDS), optical microscopy, X-ray Photoelectron Spectroscopy (XPS), and X-ray Diffraction (XRD). A preliminary test was conducted in order to examine the function of 10GDC thin film electrolytes together with the cathode and anode substrates at intermediate temperatures (700oC). A complete planar single cell was designed and assembled for this purpose. However, when fully assembled and tested, the cell failed to generate any voltage or current. Consequently, the remainder of the PhD work was focused on systematically exploring the factors contributing to the assembled fuel cell failure. As fabrication failure analysis is seldom reported in the scientific literature, this analysis represents a significant scientific contribution. This analysis proceeded in a series of steps that involved several different methods, including SEM, red dye analysis, surface morphology and cross section analysis of the cell. It was found that pinholes and cracks were present during the fuel cell operating test. Cathode delamination was also found to have occurred during the test operation. This was determined to be due to thermal expansion mismatch between the cathode substrate and the 10GDC electrolyte thin film. A series of suggestions for future research are presented in the conclusion of this work.

Zinc Oxide falls under the classification of transparent conductive oxides. They typical optical transmittance of Zinc Oxide is 90% in the visible wavelength region. Though stoichiometric ZnO is an insulator, due to the presence of internal defects such as Zn interstitials and Oxygen vacancies, it exists as a n-type conductor. The other important property of ZnO which could be used by the optical field is its widebandgap. ZnO has a wide bandgap of 3.2eV -3.3eV. The additional advantage of being a direct bandgap semiconductor has increased the probability of using ZnO for short wavelength applications. These practical applications are directly related to the fabrication of homostructural p-n junctions. ZnO can be readily doped n-type. Doping ZnO P-type is very difficult due to its native defects and the self-compensation that occurs during doping. But when P-type doping is obtained in ZnO it could be used in various optical applications such as light emitting diodes and laser diodes. This provided the motivation for this research. Theoretical studies have proposed nitrogen as a suitable material to achieve p-type ZnO. Literature provides a set of conditions that could be used to improve the doping in ZnO films. In this research, a set of these conditions were used to implement p-type doping in ZnO films. A sputtering system with a setup to support two Torus - 5M guns was used to deposit the ZnO films. A codoping technique using an aluminium doped zinc oxide target was the first method. Though an improvement in the nitrogen incorporation was found in this method in the beginning, a further increase in the nitrogen pressure did not show further improvement. A co-sputtering technique of a 99.999% pure ZnO target and a 99.99% pure Zn metal target was the second method. The ZnO target was rf sputtered while the Zn target was dc sputtered using the two guns provided in the deposition chamber. The extra Zinc obtained from sputtering the metallic Zn target was used to improve the incorporation of nitrogen. The films were later deposited in an oxygen ambient where the excess oxygen was used to suppress the oxygen vacancies that act as hole killers during the doping process. Four point probe measurement and Keithley 900 series Hall equipment were used for the electrical characterization of the films. An ORIEL monochromator was used to optically characterize the films. Hitachi S-800 T EDAX analysis system was used to measure the atomic weight % of nitrogen incorporated in the ZnO:N films. Deposition at an oxygen partial pressure of 0.3mT and 0.8mT of nitrogen produced p-type ZnO films. These films showed a carrier absorption in the short wavelength region. The carrier concentration and the mobility obtained for these films were 4.0 x1016 cm-3 and 0.12 cm2 /V-s respectively.