Unification of Excess Carrier Lifetime Measurement for Silicon PV

27th European Photovoltaic Solar Energy Conference and Exhibition; 848-851
We present a small perturbation quasi-steady-state microwave detected photoconductance decay method that is significantly improved using novel quality of decay control technique. As a result, measurements of excess carrier decay lifetime, eff.d and of the steady-state effective lifetime, eff.d are unified in one parameter-free self-consistent approach. The approach shows excellent quantitative correlation with Sinton QSSPC. Advantages of the method relate to wafer mapping. The emitter saturation current, J0, maps reveal the common presence of high J0 passivation defects that can degrade cell performance. In an automated corona-charging-measuring sequence, the approach enables quantitative assessment of the state of field-effect passivation using a novel parameter; charge to saturation, Qts. It is believed that passivation defect mapping and field-effect assessment can benefit passivation engineering for high efficiency cells.