Couplers that can couple light vertically between stacked waveguides are finding importance in the push towards higher density and lower cost optoelectronics. A compact grating coupler (12.8mum) designed by a former student is implemented in this project. The device is patterned by reactive-ion-etch into silicon-on-insulator with a 250 nm thick device layer, ensuring single mode operation. Alignment marks are patterned into the backside so that aligned bonding can be carried out. A die bonding recipe is developed using an intermediate adhesive film of SU-8-2. A novel approach to creating optically smooth input facets is included in the final steps of the process. Optical testing remains to be done.

Tiriant Frenkelio defektų dinamiką Si kristale, kai neužpildyti gardelės mazgai (vakancijos) atsiranda dėl Ožė efekto, mes pritaikėme rentgenogramas. Švitinant susidaro vakancijos taip sukariami Braggo atspindžiai ir generuojamos gardelės osciliacijos (svyravimai). / We applied soft X-rays for investigation of dynamics of Frenkel point defects in a Si crystal during the saturation with metastable vacancies generated by Auger effect. The irradiated vacancies cause the decreasing relative Bragg reflection and generates lattice oscillations.

The silicon complexes in silicon doped calcium phosphate bioceramics have been studied using $^{29}$Si magic angle spinning nuclear magnetic resonance spectroscopy. The replacement of phosphorus by silicon in these materials requires a charge compensation mechanism which is difficult to study by many experimental techniques due to the small amount of silicon added. Producing these materials using an isotopically enriched source of silicon made the use of NMR spectroscopy feasible. Three different materials have been studied: a multiphase material commercially available under the trade name Skelite$^{\rm TM}$ composed of predominantly a silicon stabilized $\alpha$-tricalcium phosphate ($\alpha$-TCP) phase as well as a silicon doped hydroxyapatite (HA) phase, a single phase Si-HA material and a single phase silicon stabilized $\alpha$-TCP material. Slight changes to the material production method were first introduced to accommodate the switch to an isotopically enriched silicon source. Characterization of the enriched materials was carried out using Rietveld refinement of X-ray powder diffraction spectra and X-ray fluorescence spectroscopy to confirm that these materials were similar to the previously studied, non-enriched, materials in terms of the silicon contents, Ca/(P+Si) molar ratios and lattice parameters. NMR Spectroscopy showed that in all three materials, the silicon formed Q$^1$ structures in which two silicate tetrahedra joined together by sharing an oxygen, creating an oxygen vacancy which compensated the substitution of two silicon for phosphorus. This is the first observation of this charge compensation mechanism in Si-HA and may explain the interesting phase evolution previously found in the system studied in this work in which the Si-HA transforms to silicon stabilized $\alpha$-TCP upon sintering. / Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2007-12-18 14:45:38.721

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Silicon-based lighting show promise for display and solid state lighting use. Here we demonstrate a novel thin film light emitting diode device using nanocrystalline silicon quantum dots as an emission layer, and metal oxides as charge transport layers. Sputtering deposition conditions for the nickel and zinc oxides were explored in order to balance deposition rate with minimal roughness, optical absorption, and electrical resistivity. Devices displaying characteristic diode current-voltage behavior were routinely produced, although most showed significant reverse saturation current due to the presence of shunts. Current-voltage behavior of devices made in the same batch showed high repeatability, however variations in device performance was observed between batches while the parameters of synthesis were kept constant. Some devices were observed to emit orange-colored light, consistent with photoluminescence behavior of the silicon quantum dots. Photomultiplier tube measurements shows a turn-on voltage of 5V and an exponential increase in light emission with voltage increase.