Trapping artifacts in quasi-steady-state photoluminescence and photoconductance lifetime measurements on silicon wafers

Abstract

Photoluminescence and photoconductance lifetime measurements on multicrystalline silicon wafers are presented. It is demonstrated experimentally that the large overestimation of the lifetime at low carrier concentrations due to trapping that is observed in photoconductance measurements is not found in photoluminescence data. This is explained theoretically by the dependence of photoluminescence and photoconductance on the product and the sum, respectively, of the minority and majority carrier densities. Based on this analysis, it is shown that photoluminescence lifetime measurements are not significantly affected by minority carrier trapping in most practical cases while implied current-voltage curves obtained from photoluminescence are completely unaffected.