Large area GaInP2/GaAs tandem cell development for space power systems

The authors report the successful fabrication of single junction GaInP₂ cells with an excellent uniformity in cell performance across 2" wafers. An average efficiency of 15.1% (with the best cell efficiency at 15.3%) under 1 sun AM0 illumination have been demonstrated on total tested areas of more than 15 cm². They also report electron radiation experiment results using 0.7, 1.0 and 2.0 MeV energies at fluences as high as 1×10¹⁶ cm^-2. The results indicate excellent resistance in GaInP₂ cells. The damage coefficients of GaInP₂ single junction cell deduced from this experiment, have been used to further refine the prediction for the performance of the tandem cell. The results indicate that the GaInP₂/GaAs tandem cell is capable of producing a minimum average cell efficiency over 25% (AM0, 28°C) at the beginning-of-life (BOL) with more than 82% remaining power after 1×10¹⁵ cm^-2, 1 MeV electron irradiation