The Property Degradation Of Triple Junction Amorphous Silicon Solar Cells Under Irradiation Of Proton And Electron

On the basis of ground-based simulation for space irradiation environment, the damage effect of the100keV proton, electron single irradiation and co-irradiation on triple-junction amorphous silicon solar cells is investigated. Meanwhile, 1MeV electron irradiation test was also carried out.I-V curves of solar cells under standard testing situation were studied to find how the electrical properties change after irradiation. Dark I-V curve, quanta efficiency, optical reflectance and surface morphology were tested to investigate the changes of PN junctions and surface materials properties after particle irradiation. According to the simulation of electron and proton irradiation on solar cells by the usage of software Casino and SRIM, with changes of solar cell properties, the mechanism of irradiation damage of solar cells was analyzed.The results show that: serious damage is produced in solar cells after 100keV electron irradiation. When the electron fluence is 5×10¹⁵/cm², the solar cell becomes invalid. After 1MeV electron irradiation, the properties degradate much, but less than 100keV electron. As for 100keV proton, the decline of properties is not much. After combined irradiation, the performance degradates more than 100keV electron. After electron irradiation, the series resistance (Rs) of solar cell increase, while the parallel resistance (Rsh) decreases as the electron fluence increases. But for proton radiation, the change of Rs and Rsh is not obvious. After 1MeV electron irradiation, the quanta efficiency (QE) decreases as fluence increase. Under the maxium fluence, the QE of solar cell after 100keV electron irradiation decreases more comparing with 1MeV electron. The results of optical reflectance test indicate that, after electron and combined irradiation, reflectance increase as radiation fluence increases; while reflectance increases as proton radiation fluence increase initially, then decreases. By using atom force microscopy, nearly no change of surface morphology is found after electron radiation; while zigzag structure can be found after proton and combined radiation.Damage caused by 100keV and 1MeV electron to the solar cells is serious, and moreover, the degradation induced by 100keV electron is more serious than 1MeV. Because of the strong penetrating power of electron, damages produce both in surface materials and PN junction region. However, most of the energies of 1MeV electron consume in substrate material, 100keV electron causes more damages in PN junctions than 1MeV electron. After 100keV proton irradiation, the degradation of solar cell performance is not so much as 100keV electron. Due to the weak penetrating ability, most of the protons stop in the surface materials, only part of them causing damages in the first PN junction, the change of solar cell properties is not so obvious. 100keV electron and proton combined radiation causes more degradation than 100keV electron single radiation, but less than the sum of degradations caused by electron and proton irradiation alone.