Polycrystalline Solar Cells From Up-graded Metallurgical Silicon.

A process to obtain solar grade polycrystalline silicon from metallurgical silicon is presented. The raw material (99% purity) is purified by chemical leaching, melted in a graphite crucible and unidirectionally solidified. Results on impurity content at each step of the process and on the final structure are presented. p-n solar cells were fabricated on selected wafers. Conversion efficiencies greater than 5% were obtained for small-area cells. Future improvements are considered.1395139