Displacement Damage Characterization of Electron Radiation in Triple-Junction GaAs Solar Cells

Abstract

The effect of space radiation environments on the degradation of triple-junction InGaP2/GaAs/Ge cells was studied to provide the reference for solar array design. The irradiationswere performedby the irradiation line-based unit-6 electron radiation facility. The solar cells were irradiated at room temperature with 0.8, 1, and 2 Mev electrons. For a given degradation level, the fluence level decreases for an increasing energy, indicating the higher energy electrons do relatively more damage. Degradation at different electron energies has been correlated with displacement damage dose. The performance of the triple-junction cells with various thicknesses of silica coverglass in a geostationaryEarth orbit radiation environment is presented. The power of the triple-junction cells will decrease to about 60%of the original value if uncovered by silica glass, while the use of a 500m-thick glass will decrease the endpower of the 15-yearmission by 30%of the original power. A 100m-thick silica glass (thickness usually used in space solar array) is not enough for blocking the electron radiation on the solar cells.