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Title:
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Possible reduction of recombination lifetime due to compensated dopants
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Author(s):
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Published by:
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Publication date:
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ECN
Solar Energy
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24-7-2007
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ECN report number:
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Document type:
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ECN-M--07-066
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Conference Paper
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Number of pages:
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Full text:
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5
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Download PDF
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Presented at: 17th Workshop on Crystalline Silicon Solar Cells & Modules: Materials and Processes, Vail CO, USA, 5-8 augustus 2007.
Abstract:
Dopant compensation is a convenient way to use all available solar grade silicon, and still arrive at the required wafer resistivity by mixing differently doped pieces of silicon. We review the possibility that compensated dopants can be a significant source of recombination in silicon solar cells, based on a variety of results in literature. The capture cross section of the ionised dopants for minority carriers is large, and not limiting recombination. Rather, the capture cross section of the neutral dopants for majority carriers is the rate-limiting parameter. There is very large variation in literature data of this neutral dopant capture cross section, between about 10-15 and 10 22 cm2. If the higher values are correct this would mean that compensated dopants can be a very significant recombination channel in solar cells. A value below, but not much below, 10-17 cm2 is most likely based on literature results, which would mean the effect would be noticeable in strongly compensated material, but not very important.
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