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Title:
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Comparison of high efficiency solar cells on n-type and p-type silicon wafers using identical processing
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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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4-2-2008
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ECN report number:
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Document type:
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ECN-M--08-006
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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: 23rd European Photovoltaic Solar Energy Conference and Exhibition, Valencia, Spain, 1-5 september 2008.
Abstract:
A low-cost, high-efficiency process on large area n-type base silicon cells is reported which is based on a screen printed aluminium-alloyed rear junction concept and phosphorus-diffused front surface field. The cell process uses fabrication techniques which are very close to the current industry-standard screen-printed mc-Si cell process for p-type wafers. An independently confirmed record-high efficiency of 17.4% (140 cm²) is achieved on n-type floatzone (FZ) silicon wafers. We compare, by experimental tests and modeling, the differences of using n-type wafers and p-type wafers with this identical process sequence. On p-type FZ wafers, with the same process 17.6% is obtained (FF of 79%), and 16.8% on p-type CZ wafers (FF of 76%). 1D-model calculations allow us to identify the potential for further enhancement of the n-type cell efficiency to above 18.0% by improving front surface passivation. We also discuss experimental characteristics and typical limitations of cells produced by this process from n-type multicrystalline wafers.
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