Electroluminescence analysis of VOC degradation of individual subcell in GaInP/GaAs/Ge space solar cells irradiated by 1.0 MeV electrons

The open-circuit voltage (VOC) degradation for individual subcell in 1.0 MeV electrons-irradiated GaInP/GaAs/Ge solar cells has been analyzed using electroluminescence (EL) measurements. By using the relationship between VOC degradation and electron fluence, the capture cross section of the defects induced by electron irradiation in individual subcells were determined. Furthermore, by comparing the thermal activation energy and capture cross section, a defect located at Ev+0.55 ​eV styled H2 hole trap is nonradiative recombination centre in GaInP subcell, a defect located at EC-0.96 eV styled E5 electron trap is nonradiative recombination centre in GaAs subcell, and a defect located at EC-0.38 eV styled E-center electron trap is nonradiative recombination centre in Ge subcell. •Electroluminescence measurements can analyze subcells' open-circuit voltage.•Determination of the relationship between open-circuit voltage and electron fluence.•Electroluminescence measurements can determine the capture cross section of nonradiative recombination center.•The H2 defect in top-cell, E5 defect in mid-cell and E-center in bot-cell are primary nonradiative recombination centres.