Determination of carrier collection length and prediction of fill factor in amorphous silicon solar cells

Abstract
Using a carrier collection length lc, defined for penetrating light, a convenient technique for measuring lc, in pin cells is demonstrated. We show experimentally that lc, predicts the fill factor measured with white light under AM1 conditions for a wide variety of pin cells. A simple model is presented which fits the experimental results. The implications of these results on the carrier collection loss for strongly absorbed light are discussed.