We present a unified lifetime measurement approach that enables self-consistent parameter-free determination of two lifetimes most frequently used in solar cell manufacturing, i.e. the excess carrier decay lifetime, τeff.d and the quasi steady-state effective lifetime, τeff. The approach uses the quasi-steady-state microwave detected photoconductance decay (QSS-μPCD) technique, whereby a small perturbation laser pulse excitation is imposed on a steady-state carrier excitation up to 25 suns. Quality of decay control, QDC, is a novel element critical for reliable measurement of τeff.d. It enables precise tuning of experimental conditions to achieve practically ideal mono-exponential decay conditions. Once the illumination characteristics of τeff.d are determined, the integration procedure of Schuurmans et.al. (1997) is used to determine the corresponding steady-state effective lifetime, τeff. Results correlate very well with QSSPC. Neither the measurement of τeff.d, nor the integration requires any wafer parameters, therefore, the determination of both lifetimes shall be considered a “parameter free” method.
