Measurements have been made on CIGS cells from ZSW, Germany to estimate minority diffusion lengths (L-n) using the photocurrent-capacitance method. An XY recorder was employed in the place of the earlier point-by-point method to measure dark and illuminated current with variation of reverse voltage to minimize drift effects. However, the obtained, L-n-values on the same cell had a wider spread of values than usual, with magnitudes too large to be acceptable. Nevertheless, it was found that pre-exposure of the cell to the light used during the measurements had a. stabilizing effect on the variation of dark current with reverse bias. As a result, part of the variation of the illuminated-to-dark current change with reciprocal capacitance was made more reproducible. Using different optical filters on light pre-soaked CIGS cells, L-n was estimated to be about 2.5 mum +/-40%.
