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Optical modeling of amorphous and metal induced crystallized silicon with an effective medium approximation

Philosophiae Doctor - PhD / In this thesis we report on the metal-mediated-thermally induced changes of the structural and optical properties of hydrogenated amorphous silicon deposited by hot-wire CVD, where aluminium and nickel were used to induce crystallization. The metal-coated amorphous silicon was subjected to a thermal annealing regime of between 150 and 520°C. The structural measurements, obtained by Raman spectroscopy, show partial crystallization occurring at 350 °C. At the higher annealing temperatures of 450°C and 520°C complete crystallization occurs. Reflection and transmission measurements in the UV-visible range were then used to extract the optical properties. By adopting the effective medium approximation a single optical model could be constructed that could successfully model material that was in different structural phases, irrespective of metal contamination. Changes in the absorption of the material in various stages of transition were confirmed with a directly measured absorption technique, and the modelled absorption closely followed the same trends This study forms part of the larger overall solar cell research project, of which the primary aim is to eventually develop a silicon solar panel that optimises the characteristics for best performance. / South Africa

Identiferoai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uwc/oai:etd.uwc.ac.za:11394/2515
Date January 2009
CreatorsMuller, Theophillus Frederic George
ContributorsKnoesen, Dirk, Arendse, Christopher, Dept. of Physics, Faculty of Science
PublisherUniversity of the Western Cape
Source SetsSouth African National ETD Portal
LanguageEnglish
Detected LanguageEnglish
TypeThesis
RightsUniversity of the Western Cape

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