Influence of depletion region width on performance of solar cell under sunlight concentration

A new interpretation of high injection effect of minority carriers,np, which is happened in solar cell under sunlight concentration and imposed a limitation on its expected efficiency- has been introduced. This interpretation declare that: increasing of minority carrier, np, recombination current Irecom in deplation region when sunlight concentration C increase,s due to the depletion layer widen because the increasing of drift electric field at the junction boundary correspond to population inversion phenomena which happens at the interfaces between the base region and the depletion region. Experiments was performed with operating solar cells under high injection conditions (sunlight concentration simulator) to get I-V characteristics, then we characterize the relation between the depletion region width w and Irecom, by suggesting a new model which enable us to optimize a solar sell under sunlight concentration. In consequence we cocnlude that: Irecom is responsible of depleting a significant part of minority carrier, consequently, Irecom causes the solar cell efficiency degradation.