Formation of alumina features and cadmium chalcogenide coatings of single-walled carbon nanotubes
Barron, Andrew R.
Doctor of Philosophy
Acetate- and methoxy(ethoxyethoxy)acetate-functionalized alumina nanoparticles (A-alumoxane and MEEA-alumoxane, respectively) have been investigated as processable, water soluble precursors to 3-dimensional (3D) ceramic features. The ceramic features can be formed by slip-casting aqueous solutions of the alumoxanes into polydimethylsiloxane molds, into which negative images of the desired features are molded. The ability to form features in the range from 50 to 450 mum in width and approximately 70 mum in depth have been investigated. The formation of the 'green body' upon drying of the alumoxane solution and its sintering to ceramic have been studied with regard to shrinkage and cracking. Physical mixtures of the two alumoxanes were investigated to determine optimum conditions for the controlled fabrication of ceramic features. Doping of MEEA-alumoxanes with metals is known to form mixed-metal phases of alumina, and the ability to form the corresponding aluminate ceramic was examined. Green body and ceramic samples were characterized by SEM, XRD, BET, and Vickers hardness measurements. Single-walled carbon nanotubes (SWNTs) and cadmium chalcogenides (CdE) are two classes of materials that have been extensively researched for applications in optoelectronics-based devices. The ability to use liquid-phase deposition (LPD) to create CdE-SWNT composites and CdE-SWNT thin coatings has been investigated in both organic and aqueous solvent systems. Raman spectroscopy has been performed on CdE-SWNT coating baths during the deposition process, to examine the effects of the combination of these two materials on the previously characterized fluorescence bands resulting from individually encased semiconducting nanotubes in micelles. Liquid-phase deposition of silica has been previously been shown to be seeded by the presence of fullerenols in solution under acidic conditions. The applicability of this mechanism towards LPD of CdS under basic conditions has been examined.
Inorganic chemistry; Engineering; Materials science