Understanding carrier lifetime measurements at nonuniform recombination

Effective lifetimes as measured via dynamic vs. steady-state techniques may drastically diverge in the presence of a highly nonuniform spatial distribution of excess carrier recombination. Based on a Green's function approach to the continuity equation, simple mode weighting rules were derived for both steady-state effective lifetime and quasi-steady-state harmonically modulated lifetime. Their validity was experimentally confirmed. Such mode weighting rules provide a full quantitative understanding of the mismatch between these two types of effective lifetime. Also, they allow the determination of individual recombination and transport properties from effective lifetimes measured at highly nonuniform configurations of recombination rate.