Calibration factors for lifetime measurements on Si ingots with alocalized PCD method solar cell fabrication

摘要

The relationship between measured effective lifetime τ_e and bulk lifetime τ_b of minority carriers insilicon ingots by a localized photoconductance decay method has beendetermined with a full 3-dimensional and transient finite-elementanalysis. For an excitation light with a spot size of 3 mm ×1 mmand an absorption coefficient of 100 cm^-1, the ratio of τ_e to τ_b ranges from 0.95 atτ_b=1 μs and a surface recombination velocityS=10² cm/s to 0.573 at τ_b=100 μs and S=10⁸ cm/s. This effect originates from both surfacerecombination and carrier diffusion from a localized light excitation