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Title:
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Solar cells from 120 PPMA carbon-contaminated feedstock without significantly higher reverse current or shunt
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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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24-9-2012
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ECN report number:
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Document type:
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ECN-M--12-046
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Conference Paper
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Number of pages:
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Full text:
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4
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Download PDF
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Abstract:
In a bid to drive down the cost of silicon wafers, several options for solar grade silicon feedstock have been investigated over the years. All methods have in common that the resulting silicon contains higher levels of impurities like dopants, oxygen, carbon or transition metals, the type and level of impurities depending on the raw materials and refining processes. In this work wafers from a p-type mc-Si ingot made with feedstock contaminated with 120 ppma of carbon have been processed into solar cells together with reference uncontaminated feedstock from semiconductor grade polysilicon with <0.4 ppma carbon. The results show that comparable reverse current, shunts, and efficiencies can be reached for both types of wafers. Gettering and defect hydrogenation effectiveness also did not deviate from the reference. Electroluminescence pictures do not show increased hotspot formation, even at -16V.
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