Selective emitter formation via single step doping through laser patterned mask oxide layer for monocrystalline silicon solar cells

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2014
Çiftpınar, Emine Hande
Selective emitter is one of the new approaches for higher efficiency solar cells. Although selective emitter cells could be processed by several different methods such as; etch back process, laser doping, ion implantation, doping paste, a different method based on diffusion through a laser patterned oxide layer was studied in this thesis. Utilization of pattern oxide layer as a diffusion barrier enables to obtain selective emitter profile via single step doping which reduces overall production cost and time significantly. In this work, selective emitter solar cells were fabricated via single step doping through a laser patterned oxide. Oxide thickness, doping recipe, laser parameters and wet cleaning steps were optimized to reach the sheet resistance values needed for an efficient cell design. In addition, surface passivation studies were also conducted to further improve cell performance. A low temperature, dry oxidation step was also added to process sequence. Then, monocrystalline-Si selective emitter and reference solar cells were fabricated. Both electrical and optical characterizations including reflection, lifetime, external quantum efficiency, Suns-Voc and current-voltage measurements were systematically carried out. It was observed that cells based on that new selective emitter structure could be used to reach higher conversion efficiency values compared to standard cell design with a proper finger design
Citation Formats
E. H. Çiftpınar, “Selective emitter formation via single step doping through laser patterned mask oxide layer for monocrystalline silicon solar cells,” M.S. - Master of Science, Middle East Technical University, 2014.