Deposition of thin material films by sputtering is an increasingly common process in the field of silicon (Si)-based photovoltaics. One of the recently developed sputter-deposited materials applicable to Si photovoltaics comprises Si nanocrystals (NCs) embedded in a Si-based dielectric. The particular case of Si nanocrystals in a Silicon Dioxide (SiO2) matrix was studied by fabricating metal-insulator-semiconductor (MIS) devices, in which the insulating layer consists of a single layer of Si NCs in SiO2 deposited by sputtering (Si:NC-MIS devices). These test structures were subjected to impedance measurements. The presence of Si NCs was found to result in two distinct capacitance peaks. The first of these peaks is attributable to the small signal response of states at the insulator/substrate interface, enhanced by the presence of fixed charge associated with the NC layer. The second peak, which occurs without precedent, is due to external inversion layer coupling, in conjunction with a transition between tunnel-limited and semiconductor-limited electron current. Si:NC-MIS devices are also potential test structures for energy-selective contacts, based on SiO2/Si NC/SiO2 double barrier structures fabricated by sputtering. Using a one-dimensional model, current-voltage (I-V) curve simulations were performed for similar structures, in which the Si NCs are replaced by a Si quantum well (QW). The simulations showed that for non-degenerately doped Si substrates, the density of defects in the SiO2 layers can strongly influence the position of I-V curve structure induced by QW quasi-bound states. Passivation of crystalline Si (c-Si) surfaces by sputter-deposited dielectric films is another major application of sputtering for Si photovoltaics. This application was explored for the cases of sputtered SiO2 and hydrogenated Silicon Oxy-Carbide (SiOC:H). For the case of sputtered SiO2, an effective surface recombination velocity of 146 cm/s was achieved for an injection level of 1E15 cm???3. The investigated SiOC:H films were found to be unsuitable for surface passivation of Si, however their passivation performance could be slightly improved by first coating the Si surface with a chemically-grown or sputtered SiO2 layer. The investigations performed into specific aspects of sputter-deposited SiO2, Si NCs, and SiOC:H have highlighted important properties of these films, and confirmed the effectiveness of sputtering as a deposition technology for Si photovoltaics.

Semiconductor nanocrystals exhibit unique optical and physical properties that make them an attractive alternative to organic dyes for fluorescent bioapplications. Although significant advances have been made since their first reported use in biology a decade ago, it still remains a challenge to prepare high quality, biocompatible semiconductor nanocrystals. / In this thesis, studies are described with the aim to prepare robust, biocompatible semiconductor nanocrystals that exhibit each of the properties necessary for their implementation in biological applications. Two different approaches were investigated: ligand exchange and polymer encapsulation, and advances in each are presented. A heterobifunctional ligand suitable for bioconjugation, carboxyl terminated dihydrolipoic acid poly(ethylene glycol) (DHLA-PEG-COOH), was synthesised and characterised to prepare water-soluble, biocompatible semiconductor nanocrystals via ligand exchange. It was found that nanocrystals transferred into water using DHLA-PEG-COOH exhibit the same optical properties and colloidal stability as those prepared using DHLA-PEG. It was demonstrated that the surface charge of the nanocrystals may be controlled by altering the ratio of DHLA-PEG:DHLA-PEG- COOH ligands. In a different approach, colloidally stable, biocompatible nanocrystals were prepared via polymer encapsulation. It was found that by employing a low molecular weight polymer, biocompatible nanocrystals that exhibit a small hydrodynamic diameter could be realised. / Experimental results are presented on the conjugation of biocompatible nanocrystals to protein targets. It was found that while standard coupling chemistries yield protein-dye conjugates, these chemistries did not result in protein-nanocrystal conjugates. In order to overcome the drawbacks of standard coupling chemistries, which are susceptible to hydrolysis, a novel conjugation scheme utilising copper-free click chemistry is proposed. / Finally, the success of nanocrystals in bioapplications depends on the ability to characterise nanocrystal-protein conjugates. By means of analytical ultracentrifugation, data on the sedimentation properties of nanocrystals and nanocrystal-protein conjugates was obtained. Analysis of these data provided information on fundamental physical properties of biocompatible nanocrystals and nanocrystal-protein conjugates, in particular the core crystal size, hydrodynamic size, number of surface ligands and nanocrystal:protein stoichiometry. Such a precise, comprehensive characterisation of nanocrystals in general, and nanocrystal-protein conjugates in particular, will greatly facilitate their use in bioapplications.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (Ph.D.)--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references.

Thesis (M. Phil.)--University of Hong Kong, 2008. / Also available in print.

Thesis (Ph.D.)--Australian National University, 2005.

Thesis (Ph.D.)--University of Melbourne, School of Chemistry, 2010. / Typescript. Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 155-170).

Thesis (Ph.D)--Materials Science and Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Speyer, Robert; Committee Co-Chair: Sanders, Thomas; Committee Member: Gerhardt, Rosario; Committee Member: Sandhage, Kenneth; Committee Member: Snyder, Robert; Committee Member: Zhang, John. Part of the SMARTech Electronic Thesis and Dissertation Collection.