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Impurities in silicon solar cellsMetallic impurities, both singly and in combinations, affect the performance of silicon solar cells. Czochralski silicon web crystals were grown with controlled additions of secondary impurities. The primary electrical dopants were boron and phosphorus. The silicon test ingots were grown under controlled and carefully monitored conditions from high-purity charge and dopant material to minimize unintentional contamination. Following growth, each crystal was characterized by chemical, microstructural, electrical, and solar cell tests to provide a detailed and internally consistent description of the relationships between silicon impurity concentration and solar cell performance. Deep-level spectroscopy measurements were used to measure impurity concentrations at levels below the detectability of other techniques and to study thermally-induced changes in impurity activity. For the majority of contaminants, impurity-induced performance loss is due to a reduction of the base diffusion length. From these observations, a semi-empirical model which predicts cell performance as a function of metal impurity concentration was formulated. The model was then used successfully to predict the behavior of solar cells bearing as many as 11 different impurities.
Document ID
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Hopkins, R. H.
(Westinghouse Research and Development Center Pittsburgh, PA, United States)
Date Acquired
August 12, 2013
Publication Date
August 15, 1985
Publication Information
Publication: JPL Proceedings of the Flat-Plate Solar Array Project Workshop
Subject Category
Energy Production And Conversion
Accession Number
Distribution Limits
Work of the US Gov. Public Use Permitted.
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