Processing and spectroscopic characterization of metal films and ceramics
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This thesis was divided into two major studies: emission and excitation studies of PLZT (lead lanthanum zirconate titanate) ceramics, and laser assisted formation of metal patterns from metalorganic thin films. Through spectroscopy studies, we were able to understand the electronic properties of PLZT samples and investigate the effect of thermally diffused metals in PLZT ceramics. Emission and excitation spectra of undoped as well as the chromium, iron, neodymium and/or praseodymium doped PLZT samples were recorded at 77K. The spectral characteristics were analyzed in light of the effects of doping atmosphere, types of dopant and concentrations of dopant: undoped PLZT has a visible absorption which was characterized by the presence of the iron impurity in the ceramics. Upon doping, an increase of optical absorptivity in the excitation spectrum was caused by the chemically active ions of the dopants. A large photocurrent was detected at 400-500 nm, correlated with the chemically active ions. However, dark conductivity also increased in the doped samples resulting from vacancy states. With respect to the survey of laser direct-writing processes for metal deposition from metalorganic complexes, excimer laser (248 nm, KrF) irradiating metalorganic spin coated thin film technique has been attempted. In order to improve the adhesion between thin films and substrates, a unique solvent mixture has been searched and applied in the metalorganic thin films preparation. A highly effective wetting agent and emulsifier, Triton X-100, is introduced to use in the thin films preparation. As applied to a substrate, this Triton/metalorganic solution promotes the formation of a uniform spin-coated thin film with good adhesion. The precursors, copper formate, copper acetylacetonate, copper hexafluoroacetylacetonate, copper chloride-18-crown-6, and gold chloride-triphenyl phosphine, were spin-coated on different substrates prepared from a series of various proportion of Triton-organic solvent. KrF laser direct-writing selectively deposited copper or gold patterns on glass, polyimide, and silicon substrates have been accomplished. When laser beam is imaged through a slit device, periodic copper metal structures with a linewidth of -3.0 jim are observed which may be attributed to the Fraunhofer diffraction.