Master of Science
Simpson, Peter J.
University of British Columbia
In the field of silicon photonics, there is an effort to bridge the gap between electrical and optical signals on a single platform, creating a need for Si-based light sources. In this project, Si quantum structures – Si quantum wells and quantum dots in SiO2 were fabricated via solid state precipitation methods. Their properties were studied using X-ray photoelectron spectroscopy, photoluminescence and I-V measurements. Rutherford backscattering spectroscopy was used for depth analysis in monitoring the Si distribution. Different electrical transport mechanisms were explored to understand how an ensemble of silicon QD’s or a silicon quantum well behaves in an SiO2 matrix, with conduction via oxide tunneling and hopping effects. Additionally, we quantified the defect density in epitaxially-grown Si and Ge thin films via RBS channeling, and correlated it with the Debye Temperature measured via low energy electron diffraction to assess the potential use of LEED as a technique for defect analysis.
Summary for Lay Audience
Conventional computers work via short-range electrical signals sent through silicon-based transistors while long distance communications primarily make use of optic fiber connections, allowing for faster communications and a much greater bandwidth. Silicon quantum dots are a known emitter of light in the near infra-red and visible range of wavelengths and while their optical characteristics are well understood, their electrical characteristics are less well documented. In this thesis, the electrical properties of silicon quantum structures were studied. A variety of experiments were done to create quantum structures within an insulating layer and then probed the sample composition and electrical and optical characteristics. Results were compared with models explaining how these quantum structures affect the characteristics of the sample. Additionally, two independent surface analysis techniques were used to probe defect structures in crystals of silicon and germanium. The results allowed us to verify a new research method for a widely used surface characterization technique. This work will enable our industrial collaborator to probe defects of these crystals during their fabrication process.
Darukhanawalla, Nazban M., "Fundamental transport properties in silicon quantum structures" (2021). Electronic Thesis and Dissertation Repository. 7608.
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