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Light and elevated temperature induced degradation (LeTID) has been studied in both gallium- and boron-doped high performance multicrystalline silicon wafers. By using hyperspectral photoluminescence imaging as a characterization tool, we wanted to investigate the differences in the defect-related photoluminescence with respect to boron and gallium doping. The samples were first light soaked (0,16 suns) at room temperature, to activate boron-oxygen light induced degradation (BO-LID). To degrade and regenerate with respect to LeTID, the samples were illuminated with an intensity of 1 sun at 130 °C. The results shows that the gallium doped samples degenerates less and slower than the boron doped samples with respect the band-to-band (BB) signal. Almost all DRL follow the same pattern. But for the D3 signal, at 0.934 eV, the time scale is different. In the gallium doped samples, the degradation and regeneration of the D3 luminescence happens slower than for the band-to-band signal. [ABSTRACT FROM AUTHOR]

Illumination at elevated temperature may cause an efficiency loss of more than 10 %rel. in mc-PERC cells. In this study, we have looked for changes in the photoluminescence spectrum of mc-PERC cells before and after light and elevated temperature induced degradation and, subsequently, after a following regeneration has commenced. We found that combined light and temperature treatment gave different responses depending on if the trap level state in the band gap was deep or shallow. [ABSTRACT FROM AUTHOR]