Analysis Of Gaas Solar Cells Performance Attenuation Caused By Space Radiation And Temperature

As it is well known that,space radiation induces degradation for solar arrays.The temperature in space also effects the power supply of solar arrays.In this paper,the electrical performances of GaAs solar cells under space radiation and temperature environment are discussed in detail.Firstly,the electrical parameters of GaAs solar cell change with its material parameters are analyzed.The results show that:the forbidden band width and carrier mobility of GaAs solar cells decrease with the increasing temperature,while the intrinsic carrier concentration and minority carrier lifetime increase,resulting in a slight increase in short-circuit current,and an decrease in open circuit voltage,maximum power,fill factor and conversion efficiency.the minority carrier lifetime of GaAs solar cells decrease with the increasing radiation,resulting in a decrease in the electrical performance parameters of the GaAs solar cell.Secondly,radiation experiments were carried out on GaAs solar cells with 150 keV protons to test the performance attenuation and the electrical performance parameters of the GaAs solar cell under different temperature conditions before and after irradiation.And the physical model was established by using COMSOL Multiphysics software.The model obtained good results in the calculation of short-circuit current and open-circuit voltage,and the calculated maximum power,fill factor and conversion efficiency were consistent with the experimental trend.The simulation and experimental results show that:with the increase of radiation,the short-circuit current of the solar cell decays more severely than the open circuit voltage.With the increase of temperature,the open circuit voltage of the irradiated solar cell decreases more than that of the unirradiated solar cell,the short-circuit current of the irradiated solar cell rises less than that of the unirradiated solar cell.For the unirradiated GaAs solar cell,the short-circuit current increased by 13.5%and the open-circuit voltage decreased by 52.6%in the space temperature of 100K to 400K.Finally,Determining the defect concentration change rate,ie the defect introduction rate under irradiation conditions and the defect generation rate under annealing conditions,as a key parameter for the combined action of radiation and temperature,and the performance degradation of solar cells under radiation and temperature conditions is analyzed.The annealing rate constants of GaAs solar cells at 50℃,70℃and 120℃were:3.55×10^-10s^-1,1.38×10^-8s^-11 and 2.53×10^-5s^-1,respectively.Taking the orbit of China space station as an example,it is calculated that the defect introduction rate in the solar cell is 4.14×10³cm^-3s^-11 in the solar maximum year and 1.02×10⁴cm^-3s^-11 in the solar minimum year respectively.Combined with the annealing rate constants at different temperatures obtained by GaAs solar cell annealing experiments,the defect generation rate of space station solar cells at different temperatures after 10 years of the solar maximum year or the solar minimum year operation is calculated.The results show that,the defect generation rate is much higher than the recombination rate at 50℃;the defect generation rate is close to the recombination rate at 70℃;the defect generation rate is significantly lower than the recombination rate at 120℃.