Defect Redistribution by Low Temperature Annealing in Ingot Silicon Solar Cells
| Autor: | Rinio, M., Yodyunyong, A., Pirker, M., Keipert-Colberg, S., Wang, P., Buonassisi, T., Borchert, D. |
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| Jazyk: | angličtina |
| Rok vydání: | 2008 |
| Předmět: | |
| DOI: | 10.4229/23rdeupvsec2008-2ao.2.1 |
| Popis: | 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 1014-1017 The influence of an annealing step at about 500 °C after emitter diffusion on multicrystalline ingot cast silicon solar cells is investigated. In 2007, Buonassisi et al. reported an increase in the whole cell efficiency due to such an anneal for 30 min. Our work now shows where on the solar cell this improvement takes place. Neighbouring wafers out of a silicon ingot were processed with and without this annealing step and were investigated by the light beam induced current (LBIC) technique. The high resolved topograms show that mainly areas with high contents of precipitates are affected by the anneal. Typically, these are areas from positions near the crucible walls. Here, also decorated grain boundaries and dislocations are improved. Therefore the positive effect is significantly seen on wafers from ingot edges and corner positions. Since more than 50 % of all wafers come from such positions, the impact of the anneal could be noticeable, even if not all of these wafers contain a deteriorated border. For future cells made of purified metallurgical grade silicon, such an anneal could significantly improve the whole cell area. |
| Databáze: | OpenAIRE |
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