Discharge Behavior And Minority Carrier Life Analysis Of GaAs Speac Solar Cells Based On Ultra-fast Spectral

In this paper,GaAs/Ge single junction solar cells and GaIn P/GaAs/Ge triple junction solar cells are taken as research objects.First,based on the ultrafast spectrum,the open circuit voltage method is used to analyze the discharge behavior of the cells,and the attenuation curves of the open circuit voltage of the cells with time are obtained,and the minority carriers' lifetime analysis is performed.On this basis,the influence of test parameters(incident light wavelength,intensity,duty ratio and strobe frequency)on the discharge behavior of solar cells is studied,and then the optimal test parameters for analyzing the minority carriers' lifetime are obtained.In addition,the optimal test parameters are used to test the minority carriers' lifetime of the space GaAs/Ge single junction solar cells and GaInP/GaAs/Ge triple junction solar cells before and after 1MeV electron irradiation,respectively.The basic law of the changes of minority carriers' lifetime of the space solar cells with electron irradiation fluence is established,and then reveal the irradiation damage mechanism of space GaAs solar cells under 1MeV electron irradiation.1.Analyzing the influence of test parameters on the minority carriers' test life of GaAs/Ge single-junction solar cells,it is found that the incident light wavelength and strobe frequency have no effect on minority carriers' test life of single-junction cells when the incident light intensity and duty ratio are constant.Under the condition that the incident light wavelength,strobe frequency and duty ratio fixed,the test life of the minority carriers GaAs/Ge single-junction solar cells decreases with the increasing of light intensity.Under the condition of certain wavelength,strobe frequency and light intensity fixed,the test life of minority carriers decreases with the increasing of duty ratio.After the duty ratio reaches 3%,the minority carriers' test life tends to be a fixed value,indicating that the test life of the minority carriers under this test condition is closer to the true life of the minority carriers.2.Based on the analysis of the influence of test parameters on the minority carriers' test lifetime of GaInP/GaAs/Ge three-junction solar cells,the results shows that the open-circuit voltages obtained by different wavelengths of incident light source are different under certain conditions of incident light intensity,duty ratio and strobe frequency.This is because incident light with wavelengths of 450 nm,800 nm,and1050 nm are mainly absorbed by GaInP top cells,GaAs intermediate cells,and Ge bottom cells,respectively.The 500 nm and 850 nm are closer to the center absorptionwavelength of GaIn P top cells and GaAs intermediate cells.With other parameters fixed,the minority carriers' test life of the three-junction cells decreases with the increasing of the incident light intensity and tends to a fixed value.And the strobe frequency of the incident light has no effect on the life of the minority carriers test.3.The test life of the minority carriers of the GaAs/Ge single-junction solar cells shortens with the increasing of electron irradiation fluence under 1 MeV electron irradiation.This is mainly because with the increase of irradiation fluence,the concentration of irradiation damage defects in the battery increases,which enhances the recombination of photo-generated carriers and leads to the gradual shortening of the life of minority carriers.In addition,with the increase of electron irradiation fluence,the open-circuit voltage of GaAs/Ge single-junction solar cells gradually decreased,which was mainly due to the enhancement of majority carriers removal effect caused by the increase of irradiation damage defect concentration.4.Under 1 MeV electron irradiation,the lifetime of the minority carriers in the GaInP/GaAs/Ge three-junction solar cells decreases with the increase of the electron irradiation fluence.When light intensity,strobe frequency and duty ratio are fixed,500 nm and 850 nm pulse spectroscopy are selected to test the minority carriers' lifetime and open circuit voltage electron irradiation before and after.It is found that the attenuation of the minority carriers' lifetime and open circuit voltage before and after electron irradiation of the three-junction solar cells is greater using 850 nm pulsed light.This shows that the irradiation of 1 MeV electrons mainly caused the damage of the GaAs intermediate battery of the GaInP/GaAs/Ge triple junction solar cells,and the resistance to irradiation of the GaInP top battery is higher than that of the GaAs intermediate battery.