Thesis (Ph. D.)--University of Alberta, 2009. / Title from pdf file main screen (viewed on Dec. 22, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Applied Mathematics, Department of Mathematical and Statistical Sciences, University of Alberta." Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (p. 133-139).

Thesis (Ph. D.)--University of Oregon, 2001. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 151-157). Also available for download via the World Wide Web; free to University of Oregon users.

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002. / Includes bibliographical references (leaves 136-146). Also available in electronic version. Access restricted to campus users.

Thesis (Ph.D.)--Drexel University, 2010. / Includes abstract. Includes bibliographical references (leaves 225-236).

Thesis (Ph.D.)--Drexel University, 2010. / Includes abstract. Includes bibliographical references (leaves 165-171).

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references. Also available in electronic version. Access restricted to campus users.

A computational investigation of some optoelectronic applications of carbon nanotubes (CNT) is presented, including CNT-based solar cells and biosensors. The results could be used to evaluate the performance of CNT devices and clarify the necessity of further experimental research in this area. A coaxially-gated CNT field-effect transistor (CNFET) forms the basic structure of the devices modeled in this thesis. Diffusive transport is present in long-channel devices, as in our case, while the quantum mechanical effects are mainly present in the form of tunneling from Schottky-barrier contacts at the metal-CNT interfaces. Band-to-band recombination of electron-hole pairs (EHP) is assumed to be the source of electroluminescence. In a first-order approximation, protein-CNT interactions are modeled as the modification of the potential profile along the longitudinal axis of CNTs due to electrostatic coupling between partial charges, in the oxide layer of the CNFET, and the nanotube. The possibility of electronic detection is evaluated. The electroluminescence of the CNT is proposed as an optical detection scheme due to its sensitivity to the magnitude and the polarity of the charge in the oxide. The validity of the model is argued for the given models. A value for the minimum required size of a computational window in a detailed simulation is derived. The structure of an electrostatically gated p-i-n diode is simulated and investigated for photovoltaic purposes. The absorbed power from the incident light and the interaction between the nanotubes is modeled with COMSOL. The results are interpreted as a generation term and introduced to the Drift-Diffusion Equation (DDE). We have observed behavior similar to that in an experimentally-realized device. The performance of CNT-based solar cells under standard AM 1.5 sunlight conditions is evaluated in the form of an individual solar cell and also in an array of such devices.

The impedance response of a quadrupolar microelectrode array was studied over a wide frequency range to determine whether particles captured at the center of the array could be detected impedimetrically. The microelectrode array (denoted as DEP chip) uses dielectrophoretic forces to concentrate particles at its center. Initial results showed that there was a large electrode-silicon-electrode (ESE) capacitance which dominated at high frequencies. This capacitance was reduced by decreasing the electrode area and increasing the insulating layer thickness. These measures however proved fruitless as this capacitance was still significantly greater then the dielectric capacitance of the chip. This ESE capacitance can be eliminated through the use of a glass substrate so that the dielectric response of the chip dominates at higher frequencies. Since the ESE capacitance prevented experimental validation of impedance spectroscopy as a signal transduction method, computer simulations were performed. These simulations indicated that capture with the current DEP chips would not have a significant impact on the impedance of the chip. Decreasing the electrode gap distance and reducing the area of the electrodes, which is recommended for future work, can remedy this. As measureable changes in the dielectric capacitance of the chip are not possible, a reaction scheme was developed to translate the capture of viral particles into a change in medium conductivity. An ELISA type system was proposed where the viral particles would be functionalized with urease. This uease would then be used to degrade non-ionic urea into ionic products thereby increasing the medium conductivity. A model was formulated to predict the conductivity increase expected for low concentrations, and validated using higher concentrations of biotinylated-urease. Urease from commercial sources proved not to be a viable option as it does not possess a high enough activity to produce a significant conductivity change given the low concentrations of viral particles expected after collection. Urease with suitable activity is produced by the organism Ureaplasma urealyticum which has an activity of 180 000 µmol urea catalyzed min-1 mg urease-1. It is not recommended that this method be pursued further due to technical challenges that would be encountered. / Thesis (Master, Chemical Engineering) -- Queen's University, 2011-05-20 02:35:15.678

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