Evaluation of the Minority-Carrier Lifetime of IMM3J Solar Cells under Proton Irradiation Based on Electroluminescence

Abstract

The shortening of the minority carrier lifetime is the main reason for the degradation of the electrical performance of solar cells; therefore, it is particularly important to evaluate the minority carrier lifetime of inverted metamorphic triple junction (IMM3J) GaInP/GaAs/InGaAs solar cells. We evaluate the minority carrier lifetime of each subcell of IMM3J solar cells before and after 2 MeV proton irradiation by the electroluminescence (EL) method. Before proton irradiation, the minority carrier lifetimes of the GaInP, GaAs, and InGaAs subcells were 6.99 × 10−9 s, 3.09 × 10−8 s, and 2.31 × 10−8 s, respectively. After proton irradiation, the minority carrier lifetime of GaInP, GaAs, and InGaAs subcells degraded significantly. When the proton fluence was 2 × 1012 cm−2, the minority carrier lifetimes of the GaInP, GaAs, and InGaAs subcells degraded to 1.63 × 10−10 s, 1.56 × 10−11 s, and 1.65 × 10−10 s, respectively. These results provide a reference for predicting the degradation of the short-circuit current and open-circuit voltage of each subcell.