Photo-recovery of electron-irradiated GaAs solar cells

摘要

The first long-term (3000 hours) UV testing of unirradiated and 1 MeV electron-irradiated GaAs/Ge solar cells, with multilayer-coated coverslides to reduce operating temperature, has produced some unexpected results. The cells used for this series of tests displayed a much higher radiation degradation than that predicted based on JPL Solar Cell Radiation Handbook data. Covered cells degraded more than did bare cells and use of multilayer coated coverslides further increased the radiation degradation in short-circuit current (Isc). Electron radiation damage to these GaAs solar cells anneals at 40 C when exposed to approximately 1 sun AM0 UV light sources. The effect appears to be linear with time (approximately 1% of Isc per 1000 UVSH), has not yet saturated (at 3000 hours), and may not saturate until recovery of electron damage is complete. If electron, and perhaps proton damage, to GaAs solar cells recovers totally with extended exposure to sunlight, the financial implications to the satellite community are immense. This effect must be confirmed by further laboratory and flight data.