Date of Award
Master of Science (MS)
Chung Hao Chen
CIGS is a major technology in photovoltaics and depends heavily, as any other PV technology, on the capacity to achieve the highest efficiency possible to compete on the market. Alkaline elements, notably sodium and potassium, play a key role in this matter as they enhance the open circuit voltage and the fill factor of the CIGS solar cells. However, this effect exists only for very specific concentration of sodium and potassium. These impurities typically diffuse through the soda-lime glass substrate.
Via modeling of the SIMS data, we try to understand and predict the diffusion mechanisms of these impurities from the glass through the molybdenum into the CIGS absorber layer. We therefore try to understand the appropriate modeling parameters that could include: grains and grain boundaries size and geometry, diffusivity in the grain and the GBs, variation of these parameters as a function of deposition process parameters such as power, pressure, Tss, and post-deposition temperature treatment. Mathematical modeling is done using MS Excel and COMSOL Multiphysics.
Akwari, Chinedum J.. "Diffusion Modeling of Impurities Through the Molybdenum Back Contact of CIGS Solar Cells" (2017). Master of Science (MS), thesis, Electrical/Computer Engineering, Old Dominion University, https://digitalcommons.odu.edu/ece_etds/25