Research And Simulation Analysis Of The Influence Of Temperature On The Radiation Degradation Of Solar Cells

Nowadays,GaAs solar cells are the main energy source for spacecraft.Researches indicated that space radiation caused gradual degradation of solar cell performance.And radiation and temperature can both effect the reliability of solar cells in space.Based on this fact,the performance of irradiated GaAs solar cells and the effect of temperature on the irradiated solar cells have been studied in this paper.Results shows that:（1）The output power of solar cells is controlled by the properties of semiconductor materials,such as band gap,carrier concentration,carrier mobility,and minority carrier lifetime,which vary with temperature.Irradiation reduces the minority carrier lifetime by introducing deep-level traps.And point defects tend to complex into clusters with increasing temperature.In addition,defects disappear by thermal annealing.（2）When the short-circuit current of solar cell decays to 90%,the non-ionizing energy deposition near the space charge region,generated by electronic,proton and Au ion are 1.44×10¹¹Me V cm^-3,1.8×10¹¹Me V cm^-3 and 1.01×10¹¹Me V cm^-3,respectively.It means that under the condition of same NIED by different irradiation,the attenuation of solar cell is larger with Au ion irradiating.After proton irradiation,the solar cells were annealed at 120°C.Result shows the electrical performance was partially recovered.The larger the irradiation flux,the lower the ratio of defect recovered.The thermal annealing speed at 120°C is 5.167×10^-4s^-1.When the Au ion irradiation is performed with temperature of 77K and 378K,the former has fewer defect clusters.During the temperature increase from 77K to room temperature after irradiation,some of isolated point defect disappeared by room temperature annealing.（3）Radiation damage in GEO is most severe compared to radiation damage in PEO and LEO.Simulation model of a single-junction GaAs solar cell was established.Geant4 and COMSOL Multiphysics were used to simulate the electrical degradation of solar cells operating in GEO at different temperatures.The result shows that the higher the temperature,the less the degradation of solar cell output.However,because the negative power temperature coefficient has a greater impact,the maximum power at high operating temperature is still smaller than lower temperature.