On the Impact of Bulk Lifetime on the Quantification of Recombination at the Surface of Semiconductors

Recombination of excess charge carriers in semiconductors occurring in emitter layers or at the interface to dielectric layers is typically assessed via injection-dependent lifetime measurements exploiting its specific injection dependence. A key assumption is that recombination in the bulk is negligible. Within this contribution it is shown in theory and experiment how neglected recombination in the bulk and its specific injection dependence can interfere with the correct assessment of surface passivation quality, in particular in the context of studies on lifetime degradation phenomena. The role of substrate doping, lifetime limitation by bulk defects and their specific properties is discussed.