Investigation of defect luminescence from multicrystalline Si wafer solar cells using X-ray fluorescence and luminescence imaging

Abstract

Multicrystalline silicon wafer solar cells reveal performance- reducing defects by luminescence. X-ray fluorescence spectra are used to investigate the elemental constituents from regions of solar cells yielding reverse-bias or sub-bandgap luminescence from defects. It is found that a higher concentration of metals is present in regions yielding reverse-bias electroluminescence than in regions yielding sub-bandgap electroluminescence. This suggests, dislocations do not create strong breakdown currents in the absence of impurity precipitates. (a) Topographies of sub-bandgap (red) and reverse-bias (blue) luminescence from defects in a multicrystalline Si wafer solar cell. (b) Their distinct X-ray spectra indicate highest concentrations of metals in the blue regions. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.