In thin film solar cells there is a front contact layer called TCO, transparent conducting oxide. This layer requires high conductivity and high transmittance. Different materials such as Tin doped indium oxide (ITO) and Aluminum doped zinc oxide (AZO) are current good alternatives but several other materials are investigated to find even better materials. One of them is tungsten doped indium oxide (IOW). This project was about investigating the deposition process for IOW and characterize the properties of IOW thin film to investigate the possibilities for implementing this material as a contact layer in thin film solar cells. The results from the two batches of depositions varied a lot. Some samples came out dark, but some were transparent and had a high transmittance, suitable for a TCO. The highest transmittance reached through this process was around 95 % in the infrared (IR) range and around 90 % in the visible range. When it comes to the resistivity, no IOW-samples reaches desired levels for a TCO. The lowest resistivity reached was 6.36 * 10-4 W cm. The results showed that the sample with the lowest resistivity was the undoped material, which is contradicting the current theory on the subject. The lowest resistivity for the IOW film was 6.50 * 10-3 W cm.

High-oxidation state main-group metal complexes are potential alternatives to transition metals for electrophilic C-H functionalization reactions. However, there is little known about how selection of the p-block, main-group metal and ligand impact C-H activation and functionalization thermodynamics and reactivity. Chapter 2 reports density functional theory (DFT) calculations used to determine qualitative and quantitative features of C-H activation and metal-methyl functionalization energy landscapes for reaction between high-oxidation state d10s0 InIII, TlIII, SnIV, and PbIV carboxylate complexes with methane. While the main-group metal influences the C-H activation barrier height in a periodic manner, the carboxylate ligand has a much larger quantitative impact on C-H activation with stabilized carboxylate anions inducing the lowest barriers. For metal-methyl reductive functionalization reactions, the barrier heights, are correlated to bond heterolysis energies as model two-electron reduction energies.In Chapter 3, DFT calculations reveal that arene C-H functionalization by the p-block main-group metal complex TlIII(TFA)3 (TFA = trifluoroacetate) occurs by a C-H activation mechanism akin to transition metal-mediated C-H activation. For benzene, toluene, and xylenes a one-step C-H activation is preferred over electron transfer or proton-coupled electron transfer. The proposed C-H activation mechanism is consistent with calculation and comparison to experiment, of arene thallation rates, regioselectivity, and H/D kinetic isotope effects. For trimethyl and tetramethyl substituted arenes, electron transfer becomes the preferred pathway and thermodynamic and kinetic calculations correctly predict the experimentally reported electron transfer crossover region.In Chapter 4, DFT calculations are used to understand the C-H oxidation reactions of methane and isobutane with SbVF5. SbVF5 is generally assumed to oxidize methane through a methanium-methyl cation mechanism. DFT calculations were used to examine methane oxidation by SbVF5 in the presence of CO leading to the acylium cation, [CH3CO]+. While there is a low barrier for methane protonation by [SbVF6]-[H]+ to give the [SbVF5]-[CH5]+ ion pair, H2 dissociation is a relatively higher energy process, even with CO assistance, and so this protonation pathway is reversible. The C-H activation/[]-bond metathesis mechanism with formation of an SbV-Me intermediate is the lowest energy pathway examined. This pathway leads to [CH3CO]+ by functionalization of the SbV-Me intermediate by CO, and is consistent with no observation of H2. In contrast to methane, due to the much lower carbocation hydride affinity, isobutane significantly favors hydride transfer to give tert-butyl carbocation with concomitant SbV to SbIII reduction. In this mechanism, the resulting highly acidic SbV-H intermediate provides a route to H2 through protonation of isobutane.

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<p>Measurements of thallium and indium doped Silicon-On-Insulator rib waveguidesshow optical absorption at a wavelength of 1550nm, dependent on the charge stateof the associated deep-level. Therefore, it is possible to use this effect to modulatewaveguide transmission by means of local depletion and/or injection of free-carriersto change deep-level occupancy. A one-dimensional model based on the generationand recombination process described by the modified Shockley-Read-Hall (SRH)mechanism was developed using MATLABc programming language in order to computethe optical absorption of a 1550nm wavelength as a function of the density ofneutrally-charged thallium or indium centers. This numerical model is in reasonableagreement with the experimental data for samples co-doped with low and mediumphosphorus concentrations. The values of optical absorption cross-section calculatedfor thallium are 2.9×10−17 ± 0.25cm2 and 3.2×10−17 ± 0.12cm2 for ion implantationdoses of 7.4×10−13cm−2 and 1.2×10−14cm−2, respectively. Also described is the thedesign, fabrication and characterization of an optical modulator using a four-terminalp+pnn+ diode on an indium-doped Silicon-On-Insulator rib waveguide. Modulationby controlling the charge state of deep impurity levels in silicon was thus demonstrated.Modulation bandwidth in the 2-10MHz regime was measured and the depthof modulation is approximately 0.48dB/V in forward bias and 0.25dB/V in reversebias. This is the first report of the implementation of an optical silicon-waveguidemodulator based on a periodically interleaved pn-junction configuration. In addition,the influence of indium, as a dopant in silicon (utilizing the Impurity PhotovoltaicEffect), as a means to increase the efficiency of a thin film silicon solar cell wasinvestigated using the same samples. Under certain doping conditions and geometricalconfigurations, a cell efficiency greater than 24% was measured —a somewhatremarkable result for these silicon thin films of 2.5μm</p> / Doctor of Philosophy (PhD)

<p>The development of nanocomposite materials has had significant influence on modern material design. Novel properties can be achieved and controlled for a diverse range of applications. The work presented here focused on characterization of polyurethane based coatings with ITO nano-inclusions. The coatings displayed high transparency in the visible range, and UV/IR shielding properties when studied with UV-Vis spectroscopy. UV/IR shielding improved with greater ITO density, with minor affect on visible transmittance. The effective medium approximation was successfully applied to ellipsometry modeling. Coatings with varying fractions of nanoparticles were analyzed. The modeled volume percent of the nanoparticles followed a strong linear trend with the known weight percentages. SEM and TEM imaging determined that majority of the particles existed in clusters. The nanoparticles were oblong shaped, 10-20nm big, randomly distributed, with no segregation to interfaces. Agglomerates varied in size, with the largest observed agglomerate being 250nm.</p> <p>Thermal stability was studied by TGA and DSC. No degradation occurred until 238°C. DSC revealed that the matrix continued to undergo modifications with consecutive runs. It was inconclusive whether the changes were from the polyurethane or dispersive agents in the system. Electron micrographs showed that segregation did not occur post-annealing. Average surface roughness increased from 3.5nm to 5nm after annealing at 120°C for several weeks. Ellipsometry results showed that film thickness decreased 20nm and 50nm before equilibriating for the 80°C and 120°C anneals respectively. The optical and thermal measurements demonstrated that the coating has great potential for improving the PV performance.</p> / Master of Applied Science (MASc)