Agradecimentos: This work was supported by the Brazilian research finance agencies FAPESP (Grant # 2012/10127-5), CNPq (Grant # 407887/2013-0), INES/INCT (Grant # 465423/2014-0) and CAPES. We are also indebted to RIMA Industrial S/A for supplying MG-Si and for the CZ growth

Abstract: Upgraded metallurgical grade silicon (UMG-Si) was obtained through metallurgical methods using two steps. First, metallurgical grade silicon was purified by the vacuum degassing technique using an electron-beam system. An ingot was then produced through Czochralski (CZ) growth. This later...

Abstract: Upgraded metallurgical grade silicon (UMG-Si) was obtained through metallurgical methods using two steps. First, metallurgical grade silicon was purified by the vacuum degassing technique using an electron-beam system. An ingot was then produced through Czochralski (CZ) growth. This later process was also used to reduce impurities through the segregation phenomenon in the CZ technique, producing a material of 99.9993% purity, one order of magnitude less pure than the minimum required for solar grade silicon. Solar cells fabricated with polycrystalline silicon with that amount of impurities are of low efficiency. Thus, the CZ technique was also adopted to supply monocrystalline silicon in order to avoid additional defects due to the grain boundary of polycrystalline wafers. Adopting this procedure, we produced solar cells with an efficiency of 13%, using a very simple fabrication process

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ

407887/2013-0

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP

2012/10127-5

COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES

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