Analysis of a technology for CZ bifacial solar cells

A bifacial cell technology for Cz Si and evaporated contacts is presented. A p/sup +/nn/sup +/ structure on high resistivity material gives 17.7% for n/sup +/ side illumination and 15.2% for p/sup +/ side illumination. Cell performance is analyzed by fitting experimental measurements with PC1D. Analysis shows that p/sup +/ layer puts a limit to cell performance, mainly due to a high surface recombination velocity. The boron depleted zone near the surface also enhances recombination, but its effect can be reduced by performing a boron etch-back step in the process. Cells with boron etch-back give higher short-circuit current and a reduction of open-circuit voltage of around 10 mV. These results are consistent with the PC1D model.