Radiation Damage Analysis of Individual Subcells for GaInP/GaAs/Ge Solar Cells Using Photoluminescence Measurements**Supported by the National Natural Science Foundation of China under Grant Nos 10675023, 11075018, 11375028 and 11675020, and the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No 20120003110011.

Abstract

The radiation damage of three individual subcells for GaInP/GaAs/Ge triple-junction solar cells irradiated with electrons and protons is investigated using photoluminescence (PL) measurements. The PL spectra of each subcell are obtained using different excitation lasers. The PL intensity has a fast degradation after irradiation, and decreases as the displacement damage dose increases. Furthermore, the normalized PL intensity varying with the displacement damage dose is analyzed in detail, and then the lifetime damage coefficients of the recombination centers for GaInP top-cell, GaAs mid-cell and Ge bottom-cell of the triple-junction solar cells are determined from the PL radiative efficiency.